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WORKS OF DR. THURSTON.
Materials of Engineering.
A work designed for Engineers, Students, and Artisans in Wood, Metal, and
Stone. Also as a TEXT-BOOK in scientific schools, showing the properties
of the subjects treated. Well illustrated. In three parts.
Part I. The Non-Metallic Materials of Engineering and
Metallurgy*
With Measures in British and Metric Units, and Metric and Reduction
Tables. 8vo, cloth $2 OO
Part II. Iron and Steel.
The Ores of Iron ; Methods of Reduction ; Manufacturing Processes ; Chemi-
cal and Physical Properties of Iron and Steel ; Strength, Ductility, Elasticity,
and Resistance ; Effects of Time, Temperature, and Repeated Strain ; Meth-
ods of Test ; Specifications. 8vo, cloth . 3 50
Part III. The Alloys and their Constituents.
Copper, Tin, Zinc, Lead, Antimony, Bismuth, Nickel, Aluminum, etc.; The
Brasses, Bronzes ; Copper-Tin-Zinc Alloys ; Other Valuable Alloys ; Their
Qualities, Peculiar Characteristics ; Uses and Special Adaptations ; Thur-
ston's "Maximum Alloys"; Strength of the Alloys as Commonly Made, and as
Affected by Conditions ; The Mechanical Treatment of Metals. 8vo, cloth, 2 5Q
"As intimated above, this work will form one of the most complete
as well as modern treatises upon the materials used in all sorts of building
constructions. As a whole it forms a very comprehensive and practical
book for engineers, both civil and mechanical." — American Machinist.
" We regard this as a most useful book for reference in its departments;
it should be in every engineer's library."— Mechanical Engineer.
Materials of Construction.
A Text-book for Technical Schools, condensed from Thurstom's " Materials
of Engineering." Treating of Iron and Steel, their ores, manufacture,
properties, and uses ; the useful metals and their alloys, especially brasses
and bronzes, and their "kalchoids": strength, ductility, resistance, and
elasticity, effects of prolonged and oft-repeated loading, crystallization and
granulation ; peculiar metals : Thurston's "maximum alloys"; stone; tim-
ber: preservative processes, etc., etc. Many illustrations. Thick Svo,
cloth ^ .
" Prof. Thurston has rendered a great service to the profession by the
publication of this thorough, yet comprehensive, text-book. . . . The
book meets a long-felt want, and the well-known reputation of its author is
a sufficient guarantee for its accuracy and thoroughness." — Building.
Stationary Steam-Engines.
Especially adapted to Electric-Lighting Purposes. Treating of the Develop-
ment of Steam-engines — the principles of Construction and Economy, with
descriptions of Moderate and High Speed and Compound Engines. Revised
and enlarged edition. Svo, cloth 2 50
* "This work must prove to be of great interest to both manufacturers and
users of steam-engines." — Builder and Wood-Worker.
OTHER WORKS OF DR. THURSTON.
A Manual of the Steam-Engine.
A Companion to the Manual of Steam-Boilers. By Prof. Robt. H. Thurs-
ton. 2 vols. 8vo, cloth $10.00
Part I. History, Structure, and Theory.
For Engineers and Technical Schools. (Advanced Courses.) Nearly noo
pages. Fourth edition, revised and enlarged. 8vo, cloth 6.00
Part II. Design, Construction, and Operation.
For Engineers and Technical Schools. (Special courses in Steam-Engineer-
ing.) Nearly icoo pages. Third edition, revised and enlarged. 8vo, cloth. 6.00
Those who desire an edition of this work in French (Demoulin's trans-
lation) can obtain it at Baudry et Cie., Rue des Saints-Peres, 15, Paris.
44 We know of no other work on the steam-engine which fills the field which
this work attempts, and it therefore will prove a valuable addition to any
steam-engineer's library. It differs from other treatises by giving, in addi.
tion to the thermo-dynamic treatment of the ideal steam-engine, with which
the existing treatises are filled ad nauseam, a similar treatise of the real
engine." — Engineering and Mining Journal, New York City.
44 In this important work the history of the steam-engine, its theory, prac-
tice, and experimental working are set before us. The theory of the steam-
engine is well treated, and in an interesting manner. The subject of cylinder
condensation is treated at great length. The question of friction in engines
is carefully handled, etc., etc. Taken as a whole, these volumes form a
valuable work of reference for steam-engine students and engineers." — Engi-
neering, London, England.
" The hope with which we concluded the notice of the first volume of this
work has been realized, and our expectations in regard to the importance of
the second have not been disappointed. The practical aim has been fully
carried out, and we find in the book all that it is necessary to know about
the designing, construction, and operation of engines ; about the choice of
the model, the materials and the lubricants ; about engine and boiler trials ;
about contracts. The volume, which closes with an original and important
study of the financial problem involved in the construction of steam-engines,
is necessary to constructors, useful to students, and constitutes a collection
of matter independent of the first part, in which the theory is developed.
77ie publication is a success worthy of all praise.'" — Prof. FRANCESCO SINI-
GAGLIA, Bollettino del Collegia degli Ingegneri ed Architetti, Naples.
Treatise on Friction and Lost Work in Machinery
and Mill Work.
Containing an explanation of the Theory of Friction, and an account of the
various Lubricants in general use, with a record of various experiments to
deduce the laws of Friction and Lubricated Surfaces, etc. Copiously illus-
trated. 8vo, cloth 3OO
44 It is not top high praise to say that the present treatise is exhaustive, and
a complete review of the whole subject." — American Engineer.
Development of the Philosophy of the Steam-
Engine.
I2mo, cloth O 75
44 This small book of forty-eight pages, prepared with the care and precision
one would expect from the scholarly director of the Sibley College of Engi-
neering, contains all the popular information that the general student would
want, and at the same time a succinct account covering so much ground as
to be of great value to the specialist." — Public Opinion.
OTHER WORKS OF DR. T HURST ON.
A Manual of the Steam- Boiler: Design, Construction,
and Operation.
Containing: — History; Structure; Design — Materials: Strength and other
Characteristics — Fuels and Combustion — Heat : Its Production, Measure-
ment and Transfer ; Efficiencies of Heating-Surfaces — Heat as Energy ;
Thermodynamics of the Boiler — Steam ; Vaporization ; Superheating ;
Condensation — Conditions Controlling Boiler-Design — Designing the
Steam-Boiler — Accessories ; Settings ; Proportioning Chimneys — Construc-
tion of Boilers — Specifications ; Contracts ; Inspection and Tests — Opera-
tion and Care of Boilers— The Several Efficiencies of the Steam-Boiler—
Steam-Boiler Trials— Steam-Boiler Explosions— Tables and Notes ; Sample
Specifications, etc.; Reports on Boiler-Trials. Fifth edition, revised. 8vo,
879 pages $500
Steam-Boiler Explosions in Theory and in Practice.
Containing Causes of — Preventives — Emergencies — Low Water — Conse-
quences— Management — Safety — Incrustation — Experimental Investigations,
etc., etc. With many illustrations, 1 2mo, cloth . -Q
" Prof. Thurston has had exceptional facilities for investigating the causes 3
of boiler explosions, and throughout this work there will be found matter of
peculiar interest to practical men." — American Machinist.
" It is a work that might well be in the hands of every one having to do
with staam boilers, either in design or use." — Engineering News.
A Hand-Book of Engine and Boiler Trials, and the
Use of the Indicator and the Prony Brake.
Nearly 600 pages. Fourth edition, revised. 8vo, cloth 5 oo
(Published also in French, as translated by M. Roussel ; Paris, Baudry
et Cie.)
•• laken altogether, this book is one which every engineei will find of
value, containing, as it does, much information in regard to Engine and
Boiler Trials which has heretorore been available only in the form of
scattered papers in the transactions of engineering societies, pamphlet re-
ports, note-books, etc." —Railroad Gazette.
Conversion Tables
Of the Metric and British or United States WEIGHTS AND MEAS-
URES. 8vo, cloth I OO
" Mr. Thurston's book is an admirably useful one, and the very difficulty
and unfamiliarity of the metric system renders such a volume as this almost
indispensable to Mechanics, Engineers, Students, and in fact all classes of
people." —Mechanical News.
Reflections on the Motive Power of Heat,
And on Machines fitted to develop that Power. From the original French of N.
L. S. Carnot. i2mo, cloth 2 OO
From Mons. Haton de la Goupilliere, Director of the EcoU National*
Superieure des Mines de France, and President of La Societe d"1 Encourage*
ment pour r Industrie Nationale :
" I have received the volume so kindly sent me, which contains the trans- ^
lation of the work of Carnot. You have rendered tribute to the founder
of the science of thermodynamics in a manner that will be appreciated by
the whole French people."
History of the Growth of the Steam-Engine.
(Pub. by D. Appleton & Co., N. Y.) i2mo, cloth I 75
Heat as a Form of Energy.
(Pub. by Houghton, Mifflin & Co., N. Y.) i2mo, cloth J 25
Life of Robert Fulton.
(Pub. by Dodd, Mead & Co., N. Y.) i2mo, cloth 75
/(
'*DEC4 1913*
A TREATISE
BRASSES, BRONZES,
AND OTHER
ALLOYS,
AND THEIR
CONSTITUENT METALS.
PART III.
MATERIALS OF ENGINEERING.
BY
ROBERT H. THURSTON, M.A., LL.D., DR. ENG'G,
LAT« DIRECTOR OF SIBLEY COLLEGE, CORNELL UNIVERSITY ; FIRST PRESIDENT AMERICAN
SOCIETY OF MECHANICAL ENGINEERS; MEMBER OF AMERICAN SOCIETY CIVIL ENGINEERS;
AMERICAN INSTITUTE MINING ENGINEERS; SOCIETE DES INGENIEURS CIVILS;
VERKIN DEUTSCHER INGENIEURE ; OESTERREICHISCHER INGENIBUR-
UND ARCHITEKTEN VEREIN ; BRITISH INSTITUTION OF NAVAL
ARCHITECTS ; FELLOW OF AM. Assoc. FOR ADVANCE-
MENT OF SCIENCE; SWEDISH ACADEMY OF
SCIENCES, ETC., ETC., ETC.
FOURTH EDITION, REVISED.
SECOND THOUSAND-
NEW YORK:
JOHN WILEY & SONS.
LONDON : CHAPMAN & HALL, LIMITED.
1910.
COPYRIGHT, 1884, 1889, 1897, 1900,
BY
ROBERT H. THURSTON.
PRESS OF
BRAUNWORTH & CO.
BOOKBINDERS AND PRINTERS
BROOKLYN, N. Y.
~A
3
PREFACE TO THE THIRD, REVISED,
EDITION. ~
THE Author and the Publishers of this work have been
agreeably surprised to find that the sale of the several vol-
umes of the treatise has been such as to compel the publica-
tion of, now, three editions of the part which, it was at the
first supposed, would find least demand. They take the
opportunity, while issuing this revised edition, to express
gratification and appreciation. The work has apparently
come to be accepted as standard, and it has become their
duty to see that it is kept fully up to the requirements of
the profession of engineering, and of those architects and
those metallurgists who find a place for it in their libraries
and on the list of their reference books.
The present edition has been improved by the correction
of every error as yet discovered by the writer, the publishers
or the readers, both professional and critical; many of whom
have taken much trouble to comply with the request printed
in the inserted slip, which will be found in every copy, asking
for such aid. It has also been given greater value, it is
thought, by the introduction of much new matter in the body
of the work, under appropriate heads, and by the extension
of the appendix ; where will be found some valuable matter
relating to recent discoveries and developments in the metal-
lurgy of the rarer of the useful metals, such as aluminium
and magnesirm, and their alloys.
It has been a source of gratification to all interested in the
work to observe that its contents have proved useful to
writers of other treatises 0:1 this and allied subjects, and that
it has furnished so large a proportion, especially, of the infor-
mation given in later publications, relative to the alloys. The
very general scrupulousness and courtesy of the authors of
such works in crediting their quotations and abstracts to this
source is a credit to such writers and a gratification to the
Author which is here heartily acknowledged.
SIBLEY COLLEGE, CORNELL UNIVERSITY,
November 10, 1897.
PREFACE TO NEW EDITION.
IN the revision of this volume for an " end of the century
edition " the author and the publishers have sought to bring
the work fully up to date in contents and make-up. The data
and statistics have been checked by reference to the latest
official reports relative to production, manufacture, and use of
the " Useful Alloys and their Constituents " ; new illustrations
have been introduced ; new and improved processes are de-
scribed, and the development of the manufacture of recently
introduced and formerly rare metals and their alloys has been
traced. The Appendix will be found to contain matter of
hardly less value than the body of the book.
Advantage has been taken of this opportunity to correct all
errors of composition which have been detected, and to repair
a\, known errors of omission as well as of commission. The
aim of author and of publishers alike has been to main-
tain the standing of this treatise on the materials of engineer-
ing as a work of reference, and to constantly improve it as a
standard in its class.
The attention of the reader unfamiliar with the older edi-
tions is particularly called to the unexampled collection of
statistics here compiled relative to the useful properties of
these materials ; the tables, especially, containing, it is be-
lieved, all needed data relative to all known metals and alloys
finding important place in the field of engineering. The
metals and compositions employed for bearings and rubbing
surfaces generally in machinery of all kinds will be seen to in-
clude those now adopted as standards in all departments of
VI PREFA CE.
construction, and by the engineers and constructors in all parts
of the world. The enormously extensive, yet by no means
complete, work of the U. S. Board appointed to test the mate,
rials of construction, of which Board the author was secretary
and editor, as well as member, is fully exhibited and all im-
portant facts reported by its committees are here recorded in
the most compact form possible, and the index to the volume
permits prompt discovery of every desired detail of information.
The author and publishers desire to express their full ap-
preciation of the favor with which this work has been received
by the profession of engineering and by constructors generally,
and will endeavor to continue to justify that favor in future
editions, should new issues be called for in the future.
They reiterate their earlier and repeated request to every
reader to assist their work by reporting promptly any error de-
tected, and any suggestion that may lead to still further im-
provement.
CONTENTS.
CHAPTER I.
HISTORY AND PROPERTIES OF THE METALS AND THEIR ALLOYS.
ART. PACK
1. Ancient knowledge of Metals 3
2. Metallurgy, Schedule of Chemical Processes 5
3. Calcination and Roasting 9
4. Smelting 1 1
5. Fluxes 12
6. Fuels 13
7. Mechanical Processes 13
8. Working of Metals 14
9. Metal defined 16
10. Useful Metals 16
1 1. Laws of Ore Distribution 17
12. Requirements of the Engineer 17
13. Special Properties of Metals 1 8
14. Non-Ferrous Metals 19
15. Relative Tenacities 19
16. Hardness 20
1 7. Conductivity 21
1 8. Lustre 24
19. Densities and Weights 25
20. Ductility and Malleability 27
21. Odor and Taste 28
22. Characteristics in General 30
23. Crystallization , 30
24. Specific Heats 31
25. Expansion by Heat 34
26. Fusibility, Latent Heat 36
27. Chemical Character 39
28. Alloys 39
Viii CONTENTS.
CHAPTER II.
THE NON-FERROUS METALS.
ART. PAG»
29. Copper, History and Distribution 42
30. Qualities of Copper 43
31. Ores and Sources 44
32. Processes of Reduction 47
33. Details 47
34. Properties of Copper 54
35. Commercial Copper 55
36. Sheet and Bar Copper 59
37. Tin, Sources and Distribution 64
38. Reduction of Ores 64
39. Commercial Tin 66
40. Zinc, History and Sources 40
41. Ores of Zinc, Smelting 41
42. Metallic Zinc 73
43- Lead 77
44. Ores of Lead , 78
45. Smelting Galena 79
46. Commercial Lead 8 1
4 7. Antimony 82
48. Bismuth and its Ores 83
49. Nickel and its Ores 84
50. Uses of Nickel 86
5 1 . Aluminium . . « 88
52. Mercury 90
53. Platinum 92
54. Magnesium 94
55. Arsenic 95
56. Indium 96
57. Manganese 97
58. Rare Metals 98
59. Commercial Metals, Prices » . . . . 99
CHAPTER III.
PROPERTIES OF ALLOYS.
60. General Characteristics IO2
61. Chemical Nature of Alloys 104
CONTENTS. IX
\RT. PAGE
62. Specific Gravity . 108
63. Fusibility no
64. Liquation 113
65. Specific Heat 1 1 6
66. Expansion by Heat 1 1 6
67. Thermal Conductivity 1 1 8
68. Electric " 120
69. Crystallization 123
70. Oxidation 1 24
71. Mechanical Properties 126
CHAPTER IV.
THE BRONZES.
72. Copper Alloys ; Bronze and Brass defined 130
73. History of Bronze 131
74. Copper-Tin Alloys 134
75. Properties 136
76. Principal Bronzes 137
77. Early Bronzes 139
78. Oriental Bronzes 140
79. Density of Bronze 141
80. Quality of Ordnance Bronze 141
81. Phosphor-Bronze 143
82. Uses of Phosphor-Bronze 145
83. Table of the Bronzes 149
CHAPTER V.
THE BRASSES.
84. Brass defined 158
85. Composition of Brass 158
86. Mallett's Classification 159
87. Uses of Brass 159
88. Muntz Metal -. 160
89. Special Properties 1 6 1
90. Application in the Arts 162
91. Working Brass 163
92. Properties of Brass 165
X CONTENTS.
CHAPTER VI.
THE KALCHOIDS AND MISCELLANEOUS ALLOYS.
A*1"- PAGB
93. Use of various Alloys 172
94. Copper-Tin-Zinc Alloys 172
95. " Iron and Zinc 174
96. " " " Tin 174
97. Manganese-Bronze 175
98. " " Preparation 176
99. Aluminium " 178
100. « " Uses 1 80
101. Copper-Nickel Alloys 181
102. " " and Zinc (German Silver) 182
103. " andiron 183
104. " Antimony 185
105. " " Bismuth 186
106. " Bismuth ; Bismuth-Bronze 186
107. " " Cadmium 186
108. " " Lead 187
109. " " Silicon 187
no. " " " ; Silicon-Bronze 188
in. " Tin and Lead 188
112. " " Antimony and Bismuth 188
113. " " Zinc and Iron 189
1 14. " and Mercury ; Dronier's Alloy 189
115. Complex Copper Alloys 189
1 1 6. Bismuth Alloys 190
117. " Tin and Lead ; Fusible Alloys 193
1 1 8. Lead and Antimony 193
119. Tin " " 198
120. " " Lead ; Fusible Alloys 198
121. " " Zinc 201
122. Antimony, Bismuth and Lead 202
123. « Tin " " 202
124. " " " Zinc 202
125 " " Bismuth and Lead * 202
126. Pewter and Britannia Metal 205
127. Iron and Manganese 202
128. Platinum and Iridium 203
129. Spence's " Metal " , 204
CONTENTS. xi
CHAPTER VII.
MANUFACTURE AND WORKING OF ALLOYS.
ART. PAGE
130. Alloy of General Use ; Brass Working 205
131. The Brass Foundry 207
132. Melting and Casting 207
133. Furnace Manipulation 209
134. Preparation of Alloys 210
135. Effect of Small Doses of Metal 212
136. Art Castings in Bronze 212
137. Stereotyping 214
138. German Silver 215
139. Babbitt's Anti- friction Metal 515
140. Solders 216
141. Standard Compositions 218
142. Special Recipes 221
143. Classified Lists 226
144. Bronzing 237
I45» Lacquering 239
CHAPTER VIII.
STRENGTH AND ELASTICITY OF NON-FERROUS METALS.
146. Strength of Non-Ferrous Metals 242
147. Resistances Classified 242
148. Factors of Safety 244
149. Measures of Resistance 246
1 50. Methods of Resistance 247
151. Equation of Resistance Curves 248
152. The Elastic Limits 249
153. Impact, Shock 251
154. Resilience 252
155. Proportioning for Shock , 255
156. Methods of Test 255
157. Compression 255
158. Structure and Composition 256
159. Transverse Stress 256
160. Distribution of Resistances 258
161. Theory of Rupture 259
Xii CONTENTS.
ART. PAGE
162. Formulas for Transverse Loading 260
163. Modulus of Rupture 262
164. Elastic Resistance 263
165. Torsional " 267
166. Strength of Shafts 268
167. Tenacity of Copper 270
1 68. Tests " " 271
169. " " Commercial Copper 272
1 70. Shearing Resistance " 277
171. Resistance to Compression 278
172. Compression by Impact 281
1 73. Transverse Tests of Copper 284
1 74. Modulus of Elasticity 286
1 75. Copper in Torsion 287
176. Mean of Results of Tests of Copper 287
177. Strength of Tin 288
178. Transverse Resistance of Tin 292
179. Modulus of Elasticity of Tin » 294
1 80. Tin in Torsion , 294
181. Strength of Zinc 296
182. Tests of Zinc 297
183. Various Metals 298
1 84. Wertheim on Elasticity 300
185. Bischoff s Tests 3°3
CHAPTER IX.
STRENGTH OF BRONZES AND OTHER COPPER-TIN ALLOYS.
186. The Bronzes denned 3°6
187. Tenacity of Gun Bronze; Wade's Experiments 3°6
188. " " " " Anderson 3°8
189. " " Bell Metal, Mallett 308
1 90. Ordnance Bronze in Compression 3°9
191. Hardness of " (Riche) 31*
192. Tenacity of Phosphor-Bronze 312
193. Resistance " " to Abrasion 3*6
194. Strength of Manganese- Bronze. S1^
195. Manganese-Bronze under Impact 3 1 7
196. Strength of Ferrous Copper 3*9
CONTENTS. Xlli
ART. PAGB
197. Copper-Tin Alloys, U. S. Board 320
198. Metals used in Research 322
199. Alloys tested 322
200. Temperatures of Casting 324
201. External appearance of Test Pieces 325
202. Behavior under Test 326
203. Appearance of Fractures 330
204. Records of Test 335
205. Final Results 341
206. Strain- diagrams of Bronzes in Tensions 344
207. Tenacities of Bronzes 344
208. Strain-diagrams of Bronzes in Compression 346
209. Transverse Strain- diagrams 348
210. Comparison of Resistances 350
211. " Resiliences 353
212. " Specific Gravities 355
213. " " Elastic Limits 358
214. " Moduli of Elasticity 361
215. " " Ductilities 361
216. " Conductivities 363
217. " Hardness, etc 363
CHAPTER X.
STRENGTH OF BRASSES AND OTHER COPPER-ZINC ALLOYS.
218. The Brasses defined 366
219. Earlier Experiments 367
220. Strength of Sterro-metal 368
221. Moduli of Elasticity 368
222. Copper-Zinc Alloys tested for the U. S 369
223. Alloys tested 370
224. Appearance of Test-pieces 371
225. " Fractures 373
226. Temperatures of Casting 275
227. Mixtures and Analyses 376
228. Results of Tests 378
229. Conclusions from Tests 379
230. Notes on Tests , 383
231. Tenacity of Brasses 384
xiv CONTENTS.
ART. FACT
232. Resistance to Compression 385
233- " " Transverse Stress 387
230- " Torsion 391
233. " of Shafts 392
336. Records of Tests 393
5*37. Strain-diagrams of Tension 404
238. " " " Transverse Tests 406
239. Resistances compared 406
240. Resiliences 409
241. Elastic Limits " 409
242. Moduli 411
243. Specific Gravities compared 412
244* Ductilities 412
245. Summary 413
CHAPTER XI.
STRENGTH OF THE KALCHOIDS AND OTHER COPPER-TIN-ZINC ALLOYS.
246. The Kalchoids 4 14
247. Sterro-metal 415
248. Copper-Tin-Zinc Alloys 416
249. Plan of Research 416
250. Selected Alloys 418
251. Details of Investigation 419
252. Method of Registry 425
353. General Deductions 427
254. Strain Diagrams 429
255. Tenacities 43°
256. Ductility 434
257. Improvement 437
258. Thurston's " Maximum " Bronzes 44°
259. Results of Tests 442
260. Discussion 443
261. Conclusions 44^
262. Other Researches 447
CHAPTER XII.
THE STRENGTH OF ZINC-TIN AND OTHER ALLOYS.
•63. Zinc-Tin Alloys 449
264. Strength and Density 45°
CONTENTS. xv
ART. PAGB
265. Grey Ternary Alloys 450
266. Earlier Investigations A 45 1
267 Records of Tests 452
CHAPTER XIII.
CONDITIONS AFFECTING STRENGTH.
268. Conditions modifying Tenacity of Non-Ferrous Metals. . . 476
269. Heat " " Copper 476
270. " " " " Bronze 477
271. " " " Various Metals 480
272. " " Elasticity 480
273. Stress produced by Change of Temperature 481
274. Effect of Sudden Variation " " 482
275. " " Chill-Casting 483
276. " " Tempering and Annealing; on Density 484
277- " " " on Tenacity 487
278. " " Temperature of Casting 488
279. " " Time of Loading 489
280. . " " Prolonged Stress on Tin and Zinc... 492
281. Effect of Prolonged Stress on Bronze 497
282. Fluctuation of Resistance 498
283. Effects of Intermitted and Steady Stress on Resistance. . 500
284. " " Stress on Deflection 502
285. « " " « " Elastic Limits 508
286. " " Variable " " " « 512
287. « « Repeated " " Strength 515
CHAPTER XIV.
MECHANICAL TREATMENT OF METALS AND ALLOYS.
288. Qualities affected by Mechanical Treatment 517
289. The Whitworth Process 519
290. The Lavroff Process 523
291. Rolling and Forging 524
292. Hydraulic Forging ; Drop Forging 525
293. Thermo-Tension ; Annealing 526
294. Cold- Working 527
295. Wire-Drawing 527
XVI CONTENTS.
ART. PACT
296. Cold-Rolling Iron; Lauth's Process 529
297. The Dean Process, applied to Bronze 530
298. Uchatius' Method 531
299. Experiments on Compressed Bronze 538
300. Uchatius' Deductions 540
301 . Frigo-Tension 540
302 . Comparison of Methods 541
303. Effect of Rolling and Hammering , 543
304. Historical ; Discoveries 546
305 . History of Experiments 548
306. " " Exaltation of Elastic Limits 552
307. " " Strain Diagrams 55 1
308. " " Processes 552
309. Cold-Working Iron 555
310. " " Bronze 556
311. Conclusions 557
APPENDIX.
Aluminium 559
Magnesium as Constructive Material 561
Production of Aluminium 567
THE MATERIALS OF ENGINEERING
PART III.
NON-FERROUS METALS.
NON-FERROUS METALS.
CHAPTER I.
HISTORY AND CHARACTERISTICS OF THE METALS AND
THEIR ALLOYS.*
I. The knowledge of metals possessed by the early
races of mankind was of the most inexact and unsatisfactory
character. They were probably led to seek a method of
utilizing them, first, by the demands of their fighting classes.
Their structures, their implements of agriculture and war, and
their domestic utensils were, in the earliest stages of their race-
history, of wood, bone, and stone. All races are found to
have advanced to their present condition of civilization from
a primitive state of barbarism, in which they were entirely
ignorant of the use of metals, and knew nothing of even the
simplest processes of reduction.
The weapons of mankind, in prehistoric times, were at h'rst
made of hard wood, of bone, or of stone, fashioned with long
and patient labor into rude and inefficient forms. As the
race advanced in knowledge and intelligence, they acquired,
by some fortunate circumstance, a knowledge of the methods
of reducing from the ores the more easily deoxidized metals,
and, still later, those which cling with tenacity to oxygen,
and require considerable knowledge and skill, and special
apparatus for their reduction to the metallic state ; and at a
still very early period, they applied the more common and
more generally useful metals in their rude manufactures.
* This introduction has been in part prefaced to Part II. on Iron and Steel,
as the volumes are published and sold separately.
4 MA TERIA LS OF ENGINEERING— NON-FERRO US ME TALS.
It has thus happened, that mankind has passed through
what are designated by the geologists as the ages of stone,
of bronze, and of iron, and may be considered as having just
entered upon an age of steel.
The ancients, at the commencement, and immediately
before the Christian era, were familiar with but seven metals.
The earliest of historical records indicate that, long pre-
vious to their date, some metals were worked, although with
rude apparatus, and in an exceedingly unintelligent manner.
Tubal Cain was an artificer in brass and in iron ; and several
sacred writers refer to the use of these metals and of gold
and silver, in very early times. Profane writers also present
similar testimony ; and the discovery of implements of metal
among the ruins of the ancient cities of Asia and Africa, and
in the copper mines and other localities of North America,
indicate that some knowledge of metallurgy was acquired
many centuries before our era.
The Hebrews were familiar with gold, silver, brass
(bronze ?), iron, tin, and lead, and possibly copper and other
metals.
Bronze and brass were not always distinguished by ancient
writers, but both alloys were known at a very early date.
Phillips gives analyses * of a number of samples of the latter
dating from B.C. 20 to B.C. 165, and bronze was certainly
made much earlier. Zinc was known in the metallic state
at some early date, while tin was known in the earliest his-
toric times.
The Chinese, at a time far back of even their oldest his-
torical records and traditions, seem to have been workers in
iron and in bronze.
Evidence has been found, in Hindostan, that the inhabit-
ants of the Indian peninsula, at an era of their history of
which we have lost every trace, were able not only to reduce
these metals from their ores by rude metallurgical processes,
but that they actually constructed in metal, works which are
looked upon as remarkable for their magnitude.
The Chaldeans, four thousand years ago, the Persians, the
* Metallurgy, 1874, p. 6.
HISTORY OF THE METALS AND THEIR ALLOYS. 5
Egyptians, and the Aztec inhabitants of America, if not an
earlier race, had some knowledge of the reduction and of the
manufacture of metals.
The " Bronze Age," in Europe, is supposed to have origi-
nated in the south of England, and to have gradually spread
over Europe, a knowledge of the methods of working copper
and bronze finally becoming very general. The bronze age
of Central America antedated that of Northern America,
where the contemporaneous age was that of copper.
It is probable that copper may have been the first metal
worked by these early metallurgists, and that tin was next
discovered and used to harden the copper, as is done at the
present time. In the manufacture of bronze, the ancients
became very skilful, probably long before the discovery and
use of iron. The bronze implements discovered on both con-
tinents have sometimes nearly the hardness and sharpness of
our steel tools.
It is only within a comparatively recent period, however,
that metallurgy has become well understood. To insure its
rapid and uninterrupted progress, it was necessary that the
science of chemistry should be first placed upon a solid basis,
and this was only done when, about a century ago, Lavoi-
sier introduced the use of the balance, and by his example
led his brother chemists to employ exact methods of re-
search.
2. The valuable qualities of the metals used in con-
struction are very greatly influenced by the presence of
impurities, and by their union with exceedingly minute
quantities of the other elements, both metallic and non-
metallic.
In the processes by which the metals are reduced from
their ores and prepared for the market, there is always
greater or less liability of producing variations of quality and
differences of grade, in consequence of the impossibility of
always avoiding contamination by contact with injurious ele-
ments during these operations, even where the ore was origi-
nally pure.
In the time of Lavoisier, but seventeen substances were
6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
classed as metals, and of these the characteristics upon which
the classification was based were principally physical, and the
place of newly discovered elements was long uncertain ;
potassium and sodium were at first (1807) classed as non-
metals.
The distinction between metals and metalloids remains
somewhat indefinite, and the type metal is considered, neces-
sarily, ideal. The metals are usually solid, mercury being an
exception ; they are usually liquefiable by heat, but arsenic
is volatile without fusing; they are generally opaque, but
gold is, in very thin leaves, translucent ; they are nearly all
malleable and ductile, but in very variable degrees. The
metals are good conductors ; the metalloids are not. The
metals are electro-positive, as a rule ; the metalloids electro-
negative.
Metallurgy is the art of separating the metals from the
chemical combinations in which they are met in nature,
freeing them from impurities with which they may be
mechanically mingled, and reducing them to the state in
which they are found in our markets, and in which they are
adapted for application in construction.
The chemical combinations from which the useful metals
are obtained, are usually either the sulphides or the oxides.
The common ores of iron are peroxides, either hydrated or
anhydrous, and copper is generally, except in the Lake Su-
perior mining region of the United States, reduced from the
state of sulphide.
Lead is usually found combined with sulphur, forming a
sulphide known as galena.
Zinc is found and mined as an oxide, as a sulphide, and
also as carbonate and silicate.
The sulphide of iron is rarely or never mined as an ore
of iron, although abundantly distributed in the form of
pyrites.
The following table * illustrates the general character of
the chief chemical processes employed for the purpose of
reducing metals of ordinary occurrence from their ores.
* Metals and Applications. G. A. Wright, London, 1878.
HISTORY OF THE METALS AND THEIR ALLOYS.
TABLE I.
REDUCTION PROCESSES IN USE.
I.— NATIVE METALS.
By mechanical means e.g. gold washing.
By simple fusion (liquefaction) e.g. bismuth.
By solution in mercury e.g. gold-quartz.
By solution in aqueous chemicals. . e.g. gold-quartz.
II. — SIMPLE ORES; i. e., containing only one metal.
A.— OXIDES.
Analytic By simple heating e.g. mercury, silver.
f By heating in hydrogen eg. nickel, iron.
Single decom- J By heating in carbon oxide e.g. iron (blast furnace).
position ... 1 By heating with carbon (coal, ) v j tin, arsenic, zinc, iron,
[ coke, etc.) \ 'a* ( antimony.
B.— CHLORIDES, FLUORIDES, ETC.
Analytic By heating alone e.g. platinum, gold.
(By heating in hydrogen e.g. silver.
By action of cheaper metal, etc.
By (a) wet processes e.g. copper, gold.
By (b) dry processes e.g. magnesium, aluminium.
By (c) amalgamation processes .... e.g. silver.
C. — SULPHIDES.
Single decom- j By heating with air e.g. mercury, copper, lead.
position ... ( By heating with cheaper metal, etc. e.g. mercury, antimony, lead.
D°comeposit?oen [ B? rofing to oxide and reducinS e.g. iron, zinc, antimony.
r 11 j i <*S 3.OOVC ............. .....••
±T <£ I B? — erting into chloride and ^
& c . . treating as above 6
composition ^
D.— CARBONATES.
Sln option0"1" By heatinS with carbon *•& zinc» sodium, potassium.
DOUe to oxide and e.g. ron.
<i-"
III. — COMPLEX ORES; \. e., containing more than one metal.
I. Alloy extracted by some or ) j silver-lead alloy,
other process, as above j" '«* \ geleisen.
II. Special processes adopted for )
extraction of metals sepa- >• e.g. cupriferous pyrites,
rately )
8 MA TERIALS OF ENGINEERING— NON-FERROUS METALS.
It is not the purpose of the Author to describe these proc-
esses at length.
In the reduction of metallic ores, the earthy impurities
are separated as completely as possible by selection, and by
mechanical methods, and the operation of smelting follows,
during which, by chemical processes, the remaining impuri-
ties, whether mechanically or chemically united with the
metal are removed. Earthy matters are removed in the
furnace, by the use of properly selected and skilfully pro-
portioned fluxes.
The ores, in their then purified condition, are deoxidized
by the action of carbon, or of carbonic oxide, at high tem-
peratures. The sulphides are decomposed by burning out
their sulphur, as it is usually found that the affinity of sul-
phur for the oxygen of the atmosphere is greater than for
the metal with which it is found in combination.
In these processes, high temperatures are requisite, as
the chemical reaction to be secured can usually only occur
satisfactorily when one or all of the substances treated are
in either the liquid or the gaseous state.
In the reduction of ores, the flux must be melted, as must
be the silica with which it is to unite, and which it is to
remove from the ore, before this desired union can take place ;
and also in order that the silicate formed may flow to the
bottom and out of the tap hole of the furnace.
The oxide left after the removal of earthy matters must
usually be brought in contact with carbon in the gaseous
state as carbonic oxide, to insure its reduction ; and the
finally reduced metal must be retained liquid, in order that it
may be conveniently removed from the furnace.
The temperatures required and allowable in reducing the
various ores are widely different. Iron, copper, bismuth,
lead, and nickel are reduced at a bright red heat ; while ores
of tin, zinc, and manganese must be made white hot — zinc
being volatilized in the process of smelting.
The process of reduction of a metal from its ores, and its
separation from earthy or metallic impurities, sometimes con-
sists of a single operation, sometimes of two or more.
HISTORY OF THE METALS AND THEIR ALLOYS. 9
3. Calcination or Roasting. — The first process to which
the ore is subjected, after leaving the mine, is frequently that
of Calcination or of Roasting, by which the ore is disintegrated,
and during which sulphur, carbonic acid, and other volatile
elements and compounds are eliminated.
In this process the ores are not mixed with a flux, and
the temperature is not raised so high as to produce either
fusion or reduction. This is found to be an economical proc-
ess with nearly all ores of iron, and it is also adopted in the
reduction of lead and zinc. The operation is performed either
in the open air or in kilns. The former method is adopted
with ores capable of withstanding somewhat elevated tem-
peratures, such as the ores of iron.
Roasting in heaps in the open air is conducted as follows :
The ground selected is first covered with a layer of wood, or
of coal six inches or more in depth. Over this is spread a
layer of ore from one to two feet thick, the quantity being
determined for each case by experience, and varying with the
character of the ore. Another layer of fuel is added, and
this is covered with another layer of ore. Alternate layers
are thus added to the pile, until it has reached the desired
height. The pile is then fired, and the ore, under the action
of the moderate temperature produced by the smouldering
fire, is slowly roasted and becomes well prepared for the suc-
ceeding process of reduction.
It loses its water, whether of combination or free, gives
up its carbonic acid, loses a portion, if not all, of the sulphur
which may have been united with it, and the disintegration
produced fits it for more thorough intermixture with fluxes,
and for more rapid and complete reduction.
The second, and the most usually satisfactory, method,
with iron ores, is that of roasting in kilns.
The fuel and the ore are charged alternately into the kilns
in such a manner as to become intimately mixed, and the
process is similar in all respects to that which goes on in
the previously described method. With kilns, however, the
operation can be carried on continuously, the roasted ore
being removed at the bottom, and new material supplied at
10 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
the top as required. This method requires comparatively
little space, and does not necessitate the accumulation of
immense masses of ore " in stock," as does calcination by the
other method. The expense of the construction of the kilns
is an objection which is usually more than counterbalanced
by the advantages of the process.
Roasting to produce oxidation is a common process in
the ordinary work of reduction of sulphides and of protoxides
in special cases. The sulphides are usually converted either
into sulphates or into a mixture of sulphate and oxide, of
which the former often decomposes at high temperature into
sulphurous acid and oxide, or oxide and basic sulphate, as
with iron or zinc ores. Arsenides and phosphides are simi-
larly treated.
Roasting to volatilize the sulphur is a common method
of treatment of iron pyrites, which yield sulphur freely by
partial decomposition. Carbonates and hydrated ores are
also thus treated to drive off carbonic acid and water. The
most common process of reduction of ores is a refined method
of reducing by roasting in a deoxidizing atmosphere, and in
contact with other reducing agents, as carbon.
The metals which are treated of in this work are all usually
found only in a state of combination with either oxygen or
sulphur, with the single exception of copper, which is often
found native, and deposits of which are sometimes very
extensive, furnishing the market with large quantities of that
metal. These oxides and sulphides are mixed with other
minerals of less valuable, of valueless, or even often of in-
jurious, character. It becomes usually necessary to melt the
" ores," as these minerals are called, to effect the separation
and reduction of the metal. This operation is called " smelt-
ing." The " wet " or " humid " processes of reduction are
but little practised in ordinary metallurgical work, although
those methods and electrolysis are occasionally found useful
and commercially economical.
The melting of common ores is not usually practised,
except as a sequel to an earlier roasting process, except in
the case of oxides of iron, which are often smelted without
HISTORY OF THE METALS AND THEIR ALLOYS. II
calcination or roasting except such as occurs within the furnace
previous to fusion. When melting does take place, it results
in reduction of the metal and its separation from the gangue
that may have accompanied it. This separation is usually
accomplished partly by the formation of a fusible slag, by
union of the gangue with a flux, which is either siliceous,
aluminous or calcareous, according to circumstances.
Melting to reduce the ore is effected by the combined
action of heat and of chemical affinity, and by the use, with
oxides generally, of carbon both as a fuel and as a reducing
agent. Sulphides of other metals than iron are reduced by
melting with that metal. Smelting with oxidation some-
times takes place, as in separating metals, or removing sulphur,
or in the manufacture of litharge, a lead oxide ; this sub-
stance is also used as an oxidizing agent with sulphides of
other metals.
Melting to effect solution is sometimes practised to secure
a separation of compounds into constituent elements or com-
pounds. Thus fused lead oxide dissolves some of the sul-
phides and many oxides. Lead itself is used in dissolving
silver and gold out of some of their ores. The alkaline car-
bonates dissolve the oxides of the metals, and borax, fluor-
spar, and other substances similarly used as fluxes act in the
same manner when employed in the production of slags.
The silicates of alkalies and alkaline earths perform the same
office as the other fluxes, and are especially valuable in the
treatment of oxides, as solvents both of some oxides and of
the gangue ; the most easily reduced oxides are dissolved by
the silicate, and go into the slag, while the less readily reduci-
ble oxides of the compound give up the metal.* Slags are
necessarily more fusible than the metal to be reduced.
Melting is often a process preliminary to volatilization, as
in the reduction of ores of arsenic and of zinc, or to separa-
tion by liquefaction and crystallization.
4. Smelting". — The final process of reduction, that of
Smelting, which usually requires still higher temperature,
and which immediately succeeds calcination, is conducted in
12 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
various ways, the outlines of which will be given in those
chapters relating to the several metals.
5. Fluxes are used in nearly all of the metallurgical
processes, and their characteristics are determined by the
special requirements of each case.
Fluxes are, as the name (from fluo, to flow) indicates, sub-
stances which assist in reducing the solid materials in the
smelting furnace to the liquid state, forming a compound
known as slag, or sometimes as cinder.
It frequently happens that two substances, having a pow-
erful arBnity for each other, will unite chemically, when
brought in contact, and fuse into a new compound at a much
lower temperature than that at which either will melt alone.
Silica fuses only at an extremely high temperature, if iso-
lated, or if heated in contact with bodies for which it has no
affinity ; but, if mixed with an alkali, as potash, soda, of
lime, the mixture fuses readily. The two first-named alkalies
are too expensive for general use in metallurgy ; but the lat-
ter is plentifully distributed, as a carbonate, and it is, there-
fore, the flux generally used in removing silica from ores, by
fusion.
Borax similarly unites with oxide of iron to produce a
readily fusible glass ; and it is, therefore, often used by the
blacksmith as a flux when welding iron.
Quartz sand is also used by the blacksmith for precisely
the same purpose. Being composed almost purely of silicic
acid, it forms a readily fusible silicate with the oxides of iron,
and it is used wherever the mass of iron is of considerable size,
and is capable of bearing, without injury, the high temperature
necessary for its fusion.
Fluor-spar, a native fluoride of calcium, has been fre-
quently and extensively used as a flux. Its name was given
to it in consequence of that fact. It is a very valuable fluxing
material, and is used where the expense of obtaining it does
not forbid its application. It has special advantages arising
from the fact that it is composed of two elements, both of
which perform an active and a useful part in the removal of the
non-metallic constituents of ores. In the removal of sulphur
HISTORY OF THE METALS AND THEIR ALLOYS. l\
and phosphorus from iron, it also possesses the great advan.
tage that the resulting compounds produced by its union with
those elements are gaseous, and pass off up the chimney, in-
stead of remaining either solid or liquid in the furnace and
contaminating the iron by their contact.
Since the aim, in selecting a flux, is usually to form, with
the impurities to be removed, a readily fusible glass, such
materials are selected, in each case, as are found, by analysis
or by trial, to unite in those proportions which produce such
a compound.
The "slag" thus formed should usually be a compound
silicate of lime and alumina, as free as possible from refractory
substances, like magnesia, and from the oxides of the metal
treated.
The flux used, therefore, where an ore contains excess of
silex, is a mixture of lime and alumina — as, for example,
limestone and clay.
Where the ore already contains alumina, limestone only
may be needed. In the reduction of iron ores, limestone is
very generally the only material added as a flux.
6. The Fuels used in engineering and metallurgy are con-
sidered very fully in Chapter IV., Part L, of this work.
7. Mechanical Processes. — Metallurgy includes both
mechanical and chemical processes. The former consist in
crushing and washing ores, or the gangue with which they
are associated, to render the processes of reduction or of
separation more easy, complete, and economical. The " stone-
breaker," or " rock-crusher," is the form of crushing apparatus
used for breaking rock into pieces of fixed size. It often
consists of an arrangement of vibrating jaw, J (Fig. i), hung
from the centre, K, and operated by a knee-joint, GEG, the
connecting-rod of which, £, is raised and depressed by a
crank, C, driven by a steam engine. A fly-wheel, B, gives
regularity of motion, and stores energy needed at the instant
when the squeeze occurs. Steel or cast-iron faces, PP,
receive the wear. The breadth of opening at /, which de-
termines the maximum size of pieces crushed, is adjusted by
a wedge at OW, set by a screw at N. The jaw is pulled back
14 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
by a spring R. Many modifications of this, the Blake crusher,
are now made.
Stamps consist of heavy weights carried at the ends of
vertical rods, which are lifted either by cams on a continuously
revolving shaft, or by the ac-
tion of a steam piston. The
former are the older, and
for many kinds of work the
most effective style ; the
latter are, however, found
vastly more economical for
other cases, as in the crush-
ing of some of the copper-
bearing rock of the Lake
Superior district.
Washing machinery is largely used in silver mining and
reduction, and less generally in working the ores of the " use-
ful " metals. It takes many forms, according to the kind of
work to be done; this is usually the washing of earthy matter
from harder ores or the separation of heavy masses from
an earthy mass in which it is imbedded.
8. The Working of Metals, as an art, antedated, un-
questionably, the very earliest historic periods, and introduced
the " age of bronze." The first metal-work was done in gold,
silver, copper, bronze, brass, lead, and iron, and possibly tin.
The East Indians, the Egyptians, the early Greeks, and per-
haps other nations, were familiar with methods of working
these metals and alloys, and are said to have been conversant
with a now unknown art of hardening and tempering bronze,
to give cutting edges on knives and weapons, which were
only equalled by those of steel. Copper was much used
during the Middle Ages, and from A.D. noo to 1500 espe-
cially, for a great variety of objects. Bronze was the most
common material for works in art among the older nations.
The metals were worked both by casting and by the
" repoussj" method. The earliest castings were solid, and
the art of economizing cost and weight by " coring out "
the inner portions was one of later introduction. The first
HISTORY OF THE METALS AND THEIR ALLOYS. 1 5
" cores " in bronzes were of iron, and were left in in the cast*
ing ; still later, removable clay and wax cores were used.
The finest Greek art-castings and those of the Romans,
and later the Italian artists, were made by the method called,
by French workers in bronze, that " a cire perdue" The
statue or other object was first roughly modelled in clay, and
in size slightly less than that proposed for the finished piece.
On this clay model was laid a coating of wax, which was
worked to exactly the intended finished size and form, and
was frequently even given the smoothness of surface desired
in the finished casting ; this formed a thin skin over the clay.
A clay, or earthy, wash was next applied, covering the wax
surface, and over this was placed a thick and strong mass of
clay, worked on in soft state and allowed to dry and set.
The whole was then baked slowly; the wax melted and
flowed out from between the two masses of clay, leaving a
space into which molten bronze was finally poured to form
the casting. The two parts of the clay mould were secured
together by stays of bronze which were built, or afterward
driven, into both parts, and thus connected them together.
When the casting had cooled, the clay was torn away from
the outside and removed from the interior of the bronze ; the
surface was finished up as required, and the work was done.
The finest antique bronzes were thus made.
The hammered, or " repousse" work of the Greeks was
wonderfully perfect at a date which is supposed to have been
earlier than that of their large castings. The first efforts in
this direction were rude ; the sheet metal was hammered into
shape over blocks of wood, which had been roughly given
the desired form. Later, a bed of pitch, or of soft kinds of
cement, was prepared, and the sheets hammered into form by
striking them on the back side, the bed yielding to the blow
and thus allowing the metal to assume the desired shape
without being broken by the hammer or by the punch used.
The work was often reversed and the final finish given on
the front side. This method produced some of the largest
and the finest of the ancient Asiatic bronzes, and fine work
in gold, silver, and copper. The Greeks excelled in this
1 6" MATERIALS OF ENGINEERING— NON-FERROUS METALS.
method of metal-working. In many cases, the thickness of
the metal was reduced nearly to that of paper, without injury
to its surface. The Siris bronzes of about B.C. 400 are of this
kind.
Tin was probably worked into vessels for domestic use by
the natives of Cornwall before the settlement of the country
by the Romans. Lead was used throughout Europe, in the
mediaeval period, in sheets for roof-coverings, and cast into
objects of complicated form. Specimens remain of the
former, exhibiting its great durability when exposed to the
weather.
Like the modern Chinese and Japanese artists, the ancient
workers in metal used gold and silver to adorn and give
relief to their castings in bronze. Mirrors, of fine surface
and thus ornamented, are common among collections of the
products of Greek art. The bronzes of the Italian artists of
the Middle Ages are remarkable for their beauty as art work
in metal, as well as for their beauty of design ; even their
work in iron is famous for its unexcelled beauty and the skill
exhibited in forging it. Modern work has not equalled that
of the Middle Ages, or even that of the early Greeks.
9. Metal is the name applied to above fifty of the chem-
ical elements. The larger number of the metals are but
little known, and many are found in such extremely minute
quantities, that we are not well acquainted with either their
chemical or their physical characteristics. Some approach
the non-metallic elements so nearly in their properties, that
they are placed, sometimes in the one class, and sometimes in
the other. Very few of the metals are well fitted for use in
construction; but, fortunately, those few are comparatively
widely distributed, and are readily reduced from their oxides
or sulphides, in which states of combination they are almost
invariably found in nature.
10. The " Useful Metals " are iron — in its various forms
of cast iron, malleable or wrought iron, and steel — copper,
lead, tin, zinc, antimony, bismuth and nickel, and occasionally
aluminium and rarer metals are used for similar purposes.
From this list of metals, and from their alloys, the engi-
HISTORY OF THE METALS AND THEIR ALLOYS. 1 7
neer can almost invariably obtain precisely the quality of
material which he requires in construction. He finds here
substances that exceed the stones in strength, in durability
under the ordinary conditions of mechanical wear, and in the
readiness and firmness with which they maybe united. They
are superior to timber of the best varieties in strength, hard-
ness, elasticity and resilience, and have, in addition, the im-
portant advantages, that they may be given any desired form
without sacrificing strength, and may be united readily and
firmly to resist any kind of stress.
By proper selection or combination, the engineer may
secure any desired strength, from that of lead, at the lower,
to the immense tenacity of tempered steel, at the upper
limit. He obtains any degree of hardness, or fusibility, and
almost any desired immunity from injury by natural destroy-
ing agencies. Elasticity, toughness, density, resonance, and
varying shades of color, smoothness, or lustre, may also be
secured.
11. The Laws Governing Distribution of the Ores of
the metals are comprehended in the science of geology. The
detection of their presence in any locality, and bringing them
to the surface of the ground, free from the foreign earthy
substances which accompany them, is the work of the min-
ing engineer, and of the miner. The " reduction" of the
metals from ores, by chemical and mechanical processes, con-
stitutes the business of the metallurgist. The engineer takes
the metals as they are brought into the market, and makes
use of them in the construction of permanent or movable
structures.
12. The Requirements of the Engineer include some
acquaintance with the general principles, and with the ex-
perimental knowledge, which are to be obtained by the study
of geology, of mining, and of metallurgy, to aid him in select-
ing the metals used in his constructions ; since their quali-
ties cannot always be determined by simple inspection, and
it is not always possible to subject them to such tests as he
may consider desirable before purchasing. In such cases, a
knowledge of the localities whence the ores were obtained,
2
1 8 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
familiarity with the processes of manufacture, and with the
nature of the materials employed by the metallurgist, coupled
with a knowledge of the effects of various foreign substances
upon the quality of the metal, may enable the engineer to
judge with some accuracy what metal will best suit his pur-
poses, and what will be likely to prove valueless. He is also
thus enabled to judge, should the purchased material prove
defective, where the defect in quality originated, and to place
the responsibility where it belongs.
The student will seek this knowledge in special works on
geology and metallurgy. But brief reference can be made to
these subjects here.
All the metals possess, as a whole, a number of properties
which define the class, although few of these properties are
common to all. The metals all unite chemically with oxygen
to form basic oxides, and some of them take higher proportions
of oxygen, forming acids. All metals are capable of similarly
uniting with chlorine. All are capable of fusion and lique-
faction at certain temperatures, fixed for each, which are
usually high. Mercury, however, is liquid at ordinary tem-
peratures. The metals are also capable of vaporization, and
their vapors have some physical characteristics quite different
from those of the solid metal. Thus, silver, white when solid
or liquid, becomes blue as a vapor ; mercury vapor is color-
less, potassium is green. All are opaque, except in exceed-
ingly thin films, when some become apparently translucent.
Gold transmits green light, mercury blue, and silver remains
opaque in the thinnest leaf yet made.
13. The Special Qualities of the Useful Metals which
give them their importance as materials of construction are :
their strength, hardness, density, ductility, malleability, fusibil-
ity, lustre, and conductivity.
Strength, or the resistance offered to distortion and fract-
ure, is their most valuable quality. The strength of metals
and alloys in general use has been very carefully determined
by experiment, and will be given hereafter.
Of the metals in our list, lead is the least tenacious, and
steel is the strongest.
HISTORY OF THE METALS AND THEIR ALLOYS. 1 9
14. The Non-Ferrous Metals, which are to-day of com-
paratively little importance to the engineer in the construction
of machines or of structures, and which have been so generally
superseded by iron and steel in every department of art, were,
in earlier times, in some cases, as copper, tin, lead, the most
common materials,.of construction. The three just mentioned
were known in prehistoric times, and the Greeks were also
familiar with mercury, as well as with iron. Valentinus dis-
covered and described antimony in the I5th century, and
bismuth and zinc became known at about the same time or a
little later. Brande discovered arsenic and cobalt about the
middle of the i8th century, and Ward discovered cobalt.*
Cronstedt discovered nickel and Scheele manganese in 1774,
and tungsten was prepared in 1783 by the brothers D'Elhu-
jart. Palladium, rhodium, iridium and osmium were isolated
and described by Wollaston and others in 1803. The alkaline
earths, recognized as oxides by Davy in 1807-8, were soon
after deoxidized, and potassium and sodium became known.
Aluminium and magnesium were separated in 1828 and 1829,
respectively by Wohler and by Bussy, and cadmium had
already been discovered by Stromeyer in 1818. The rarer
and more unfamiliar metallic elements were found later.
The properties of these metals have been referred to in a
general way in an abridged account of them given in Part II.
of this work. A more detailed account of those used in con-
struction will occupy the greater part of this volume. The
following is a resumt of the general characteristics of these
metals.
15. The Relative Tenacities are approximately as below,
lead being taken as the standard.
TABLE II.
RELATIVE TENACITIES OF METALS.
Lead i.o
Tin 1.3
Zinc 2.0
Worked copper 12 to 20
Cast iron 7 to 12
Wrought iron 20 to 40
Steel 40 to 100
* Encyclopaedia Britannica, 1883, art. Metals.
2O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
No two* pieces of metal, even nominally of the same grade,
have precisely the same strength. The figures can therefore
only represent approximate ratios, as every variation of
purity, structure, or even of temperature, is found to affect
their strength.
Cast metal is usually weaker than the same metal after
having passed through the rolls or under the hammer ; those
which can be drawn into wire are still more considerably
strengthened by that process. Metals are stronger at ordi-
nary temperatures than when highly heated, and " annealing "
is found to reduce the strength of iron and steel, although
frequently increasing their ductility, and produces an op-
posite effect on copper and its alloys. " Hardening," pro-
duces the contrary effect. The presence of impurities and
the formation of alloys produce changes of strength, some-
times increasing, sometimes diminishing it.
Copper alloyed with tin or zinc, in certain proportions, is
strengthened ; and the addition of a small percentage of
phosphorus to the alloy has a marked effect in increasing its
tenacity and ductility.
16. Hardness varies in the metals as considerably as their
tenacity, and, like the latter quality, is greatly influenced in
the same metal by very slight changes, either physical or
chemical.
Thus metals are hardened by cold hammering and softened
by sudden change of temperature. The addition of scarcely
more than a trace of impurity often produces a marked
change in the degree of hardness of metals.
The scale of hardness, according to Gollner,* is as follows:
Soft lead i
Tin 2
Hard lead 3
Copper 4-5
Alloy for bearings
(C.,85; T., io;Z.,5). 6
Soft cast iron 7
Wrought iron 8
Cast iron lo-n
Mild steel 12-13
Tool " blue 14
" violet 15
" " straw 16
Hard bearings
(C., 83; Z., 17) 17
Very hard steel 18
* Tech. Blaetter; London Engineering, June i, 1883, p. 519.
QUALITIES OF THE METALS AND THEIR ALLOYS. 21
The hardness of metals, as determined by Dumas, is
exhibited in the following table of their order.
TABLE III.
HARDNESS OF THE METALS.
Titanium ',
Manganese
Scratch steel.
Chromium
Rhodium
Scratch glass.
Platinum
Nickel
Palladium
Cobalt
Copper
Iron
- Scratched by
Gold
Silver
Tellurium
Bismuth
Scratched by
' CalcSpar.
Antimony
Zinc
Lead
Scratched by
the nail.
Cadmium
Potassium ) c (,
Tin J
Sodium \ Softaswax.
Mercury, Liquid.
17. Conductivity, or their power of transmitting molecu-
lar vibrations of either heat or electricity, is another property
of the metals, upon which is founded many useful applications.
Of the " useful " metals, copper has by far the highest
conductivity, and is only second in this respect to gold and
silver, the best known conductors. Its conductivity is greatly
reduced by the presence of foreign substances.
The powers of conduction for heat and electricity seem
to have very similar relative values. Conductivity is reduced
by increase of temperature and by presence of impurities.
The following table of relative conductivities was deter-
mined by the experiments of Despretz, and very closely con-
firmed by Forbes.
TABLE IV.
RELATIVE THERMAL CONDUCTIVITIES .OF METALS.
Gold 1,000
Silver 973
Copper 878
Iron 374
Zinc 360
Tin 304
Lead 180
Marble 25
The electric conductivities obtained by Becquerel, and the
22 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
thermal conductivities given by Wiedmann and Franz, are as
below : *
TABLE IVa.
CONDUCTIVITIES OF METALS.
ELECTRIC.
THERMAL.
In Vacuo.
In Air.
Silver
1,000
I,OOO
'748
548
240
154
84
79
1,000
'736
532
236
145
840
85
18
" commercial . . . .
915
649
Gold
Brass . « . ...
Tin
140
79-3
82.7
Lead . .
The resistance to the voltaic current has been found by
Mr. K. H edges \ as follows, wire and foil being used, and
strength of the current so adjusted that on increasing it 20
per cent, the metal would fuse. The experiments continued
24 hours and the temperature was 69° F. (21° C.)
TABLE V.
RESISTANCES OF METALS TO ELECTRIC CURRENTS.
METAL,
Before Heating.
Change in
24 Hours.
0.815 Ohms.
— 0.003
0-835
— 0.005
0.810
+ 0.000
0.860
+ o.ooo
0.800
— 0.160
0.8^
+ o ooo
7o Aluminium and tin . . .
0.820
+ 0.0008
RESISTANCES AS MEASURED.
* Part II., p. 8, § 10.
f Brit. Assoc. Reports, 1883, Sec. G.
QUALITIES OF THE METALS AND THEIR ALLOYS. 2$
Commercial copper (Rio Tinto), has been found to have,
in some cases, but one-seventh the conductivity of pure
copper.
Conductivity is reduced by increase of temperature, ac-
cording to Forbes, and at rates varying with the character of
the metal.
M. Benoit has measured the electrical resistance of various
metals at temperatures from o° to 860° C. The mean of the
figures obtained is given in the following table, the second
column giving the resistance in ohms of a wire 39.37 inches
(i metre) long, and having a cross section of 0.03 inch (i sq.
cm.), and column three the same quantity in Siemens
units. Column four gives the conductivity compared with
silver :
TABLE V*.
METAL.
OHMS.
SIEMENS.
Silver A . • ....
.Om4
0161
IOO
Copper A
OI7I
OI7Q
oo
Silver A.(i)
.OIQ^
O2OI
yo
80
Gold, A
.O2I7
.O227
71
Aluminium A . . . .
O3OQ
O324
4Q 7
Magnesium H
.04.23
O443
on 4
Zinc, A , at 350°
.(x6<?
.(XQI
27 ^
Zinc, H
.(KQ4
.0621
2C .Q
Cadmium, H
.068^
0716
22 ^
Brass, A. (2)
.O6oi
.0723
22 3
Steel, A
. IOQQ
. II4Q
14
Tin
iwVV
1161
1214
TO 0
Aluminium bronze A (3) . .
IlSg
12/17
1 3
Iron, A
. 1216
1272
12 7
.1-284
1447
III
Platinum A
IC7C
l6d7
977
Thallium . .
iS'U
IQI4
8 41
Lead
.1085
.2O7«;
77 60
German silver, A. (4)
»ywj
.2654
.2775
5. 80
.Q564
I . OOOO
I.6l
A, annealed; H. hardened; (i) silver .75; (2) copper 64.2, zinc 33.1, lead 0.4, tin 0.4;
(5) copper 90, aluminium 10 ; (4) copper 50, nickel 25, zinc 25.
These results, are all taken at o° C., and agree closely with
those obtained by other observers. The resistance increases
regularly for all metals up to their points of fusion. This
24 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
increase, however, differs for different metals. Tin, thallium,
cadmium, zinc, lead, are found to vary similarly ; at 200° to
230° their resistance has doubled. The resistance of iron and
steel doubles at 180°, quadruples at 430°, and at 860° is about
nine times that at o°. Palladium and platinum increase much
less, their resistance becoming twice that at o° C., at 400° to
450°. Gold, copper, and silver form an intermediate group.
In general conductibility decreases more rapidly the lower its
point of fusion. Iron and steel are exceptions to this rule.
In alloys the variation is less than in their constituents, and
this is especially the case with German silver.
The thermal conductivity of brass was found by Isher-
wood to be 556.8 thermal units (British) per hour per square
foot and per i° Fahr., and to vary at the difference of tem-
perature.
Silicon-bronze may be given a conductivity but little less
than that of copper, but its tenacity then diminishes con-
siderably; that having 95 per cent, the conductivity of
copper, has but one half the strength of that of which the
conductivity is 25 per cent.
18. The Lustre of these metals is measured by their
power of reflecting light. Thus, according to Jamin, silver
may reflect 0.9 of the light sent between surfaces of mirrors
made of that metal ; after ten normal reflections it yields
from 0.24 to 0.48, the former figure being that for violet, and
the latter for red light. The figures for speculum metal are
0.6 to 0.7, 0.006 and 0.035 ; those for steel, 0.6, 0.006, and
0.007.
Estimating weights of metal in various forms as used by
the engineer is a simple operation. Thus : if
d = diameter of a circular section, or the minor diameter
of an ellipse;
d' = major diameter of ellipse ;
/ = length of piece, section uniform ;
b = breadth ;
k = a constant ;
W '= total weight.
QUALITIES OF THE METALS AND THEIR ALLOYS. 2$
The weight of any piece of uniform section is
W ' = kd2l for cylindrical bars ;
= kdd'l " elliptical sections ;
= kbdl " rectangular sections.
The values of k when / is in feet, other dimensions in
inches and W in pounds, are
VALUES OF h IN
W= kdcfl.
,r-«*
2.906
o 700
2 618
•1 OO-I
Lead sheet .
3 888
4 05O
Steel, soft
2 67O
3. J.OO
For pipes, W= k(d? — df) when d^d2 represent the inner
and outside diameters in inches.
To obtain weights in kilogrammes when measures are in
centimeters, multiply the above by 0.00241.
The " metallic lustre " is a property of the metals almost
peculiar to them, and constitutes one of their marked charac-
teristics.
Polished steel, and an alloy of copper and tin known as
speculum metal, burnished copper and aluminium, as well as
the precious metals, gold and silver, exhibit this beautiful
and peculiar lustre very strikingly.
Tin, lead, and zinc, are lustrous, but they are not capable
of taking a sufficiently high polish to exhibit this quality in
such a degree as the metals first named.
19. The Specific Gravities of the commercial metals are
as follows :
THE DENSITIES OF PURE METALS according to Fownes,*
are
* Chemistry, roth ed., p. 297.
26 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
TABLE VI.
SPECIFIC GRAVITIES OF PURE METALS.
(Water at 60° F. (15.5 C.) = i.)
Platinum 21 . 50
Iridium 21.15
Gold 19.50
Tungsten 17.60
Mercury 13-59
Palladium 11.80
Lead H-45
Silver 10. 50
Bismuth 9 . 90
Copper 8 . 96
Nickel 8.80
Cadmium 8.70
Molybdenum 8 . 63
Cobalt .................. 8.54
Manganese .............. 8 . oo
Iron ................... 7 .
Tin .................... 7.
Zinc .................... 7.
Antimony ............... 6.
Tellurium ............... 6
Arsenic ................. 5
Aluminium .............. 2 . 67
Magnesium ............. 1.75
Sodium ................. 0.97
Potassium ............... 0.87
Lithium ................ o. 59
For the purposes of the engineer, the densities and the
weights per unit of volume of commercial materials are the
data desired. The following table gives such a set of figures.
As is seen by comparing the tables, authorities differ some-
what in these figures.
TABLE VII.
WEIGHTS AND DENSITIES OF COMMERCIAL METALS.
NAME.
S. G.
LBS. IN
CU. FT.
KILOG'S
IN CU. M.
Aluminium cast
2.56
160
2,560
sheet
2.67
167
2,670
Antimony cast «.
6.7
418
6,700
Bismuth " .
Q 8
6l4.
9 800
Brass * cast ..
8.4
525
8,400
sheet
8.5
S32
8,500
" wire . . . . .
8.54
C-J-3
8,540
8.4
524
8,400
8.85
548
8,850
8.60
K37
8,600
" sheet
8.88
54Q
8,800
8.88
55O
8,800
Gold hammered • . . ... ...
IQ 4
I.2O5
IQ 400
" standard
17-65
i»iO3
17,650
Gun metal (bronze). .
8.111
510
8,153
QUALITIES OF THE METALS AND THEIR ALLOYS. 2J
TABLE Nil.— Continued.
NAME.
S. G.
LBS. IN
CU. FT.
KILOG'S
IN CU. M.
Iron, cast, from . .
6 Q5H
A'IC.
6 Q55
'« to
7.201;
4^6
U>V33
72QC
7. 125
A AC.
7 125
wrought, from
7 560
AT*
7e6o
" to
7 8oO
488
7 800
7.680
4.80
7 680
Lead cast ..
II ^52
7IO
II 752
" sheet
II .4
712
II J.OO
Mercury, fluid
13 6
8d8
13 6OO
•« solid
IS .6^2
Q77
je 6^2
Nickel, cast
7.807
488
7,8O7
Pewter
II 600
725
1 1 6OO
Platinum, mass
IQ. 55O
I 219
IQ. 5OO
" sheet
2O. 337
1,271
2O ^7
Silver, mass
IO 5
655
10 500
IO 5^4
658
IO ^^J.
Steel, hard
7 82
406
7.82O
" soft
7.834
4QI
7.834
Tin,* cast
7. 3
4^6
7 ^OO
IO.45O
653
IO.4CO
Zinc,* cast
7.03
430
7 O^O
" sheet
7 2Q
456
7 2OO
20. Ductility and Malleability are properties of the met-
als scarcely less important to the engineer than that of
tenacity. The ductility of a metal or an alloy is its capacity
for being drawn out into wire, by being pulled through holes
in the wire-drawers' plates, each hole being slightly smaller
than the preceding, until the wire reaches a limit of fineness
which is determined by the degree of its ductility, and, as
well, by the skill of the workman.
Great tenacity, in proportion to the degree of hardness,
or high tenacity, a low elastic limit and a certain viscosity,
is the combination of qualities required to insure dura-
bility.
Gold has been drawn until the wire measured but •gl5101>
inch in diameter, and silver and platinum are nearly as duc-
tile. Iron and copper are the most ductile of the common
metals.
* See text later.
28 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The malleability of a metal, or the power which it pos.
sesses of being rolled into sheets without tearing or breaking,
is determined by its relative tenacity and softness.
The malleability of the non-ferrous metals is determined
by their plasticity simply, and this quality is observable in
all metals having no defined elastic limit. It is also often
determined to some extent by the physical condition of the
metal; thus zinc, brittle in the ingot, is malleable at the
boiling temperature of water, and, if worked at that tempera-
ture, becomes permanently malleable in the sheet or the bar.
Hardening and tempering are operations which can be per-
formed on many metals with the effect of modifying their
malleability and other properties ; but while sudden cooling
from high temperature hardens steel, it softens copper and
the bronzes and brasses. Ductility, being dependent upon
tenacity largely, is not as generally observed as malleability.
Gold is the most malleable of all metals, and has been
beaten into sheets of which it would require 300,000 to make
up a thickness of one inch.
Wrought iron of good quality, and the softer grades of
steel, are very malleable; the former has been rolled to less
than Y-J0-0 of an inch (0.00254 centimetre) thickness. Cait
iron and hard steels are neither malleable nor ductile.
Copper is very malleable, as well as ductile, if kept soft
by frequent annealing ; tin possesses this property, also ; and
zinc, although quite brittle when cold, becomes malleable
at a temperature somewhat exceeding the boiling point of
water ; its temperature being still further elevated, it again
becomes brittle, so much so that it may be powdered in a
mortar. Some of the copper-tin alloys exhibit the same
peculiarity.
21. Odor and Taste characterize many metals. Brass, for
example, possesses a very marked taste and perceptible odor
when applied to the tongue and when rubbed. These qual-
ities may indicate solubility and volatility, but no direct ex-
periment has revealed their precise nature. Many of the
lighter metals are quite volatile at moderately high tempera-
ture.
QUALITIES OF THE METALS AND THEIR ALLOYS. 2$
Lead can be rolled into quite thin sheets, but it is less
malleable than either copper, tin, or the precious metals.
The following is a table of the relative ductility of metals:
TABLE VIII.
ORDER OF DUCTILITY OF METALS.
1. Gold, 4. Iron, 7. Zinc,
2. Silver, 5. Copper, 8. Tin,
3. Platinum, 6. Aluminium, 9. Lead.
In the following list, the metals named are placed in the
order of their malleability.
TABLE IX.
ORDER OF MALLEABILITY OF METALS.
1. Gold, 4. Tin, 7. Zinc,
2. Silver, 5. Platinum, 8. Iron,
3. Copper, 6. Lead, 9. Nickel.
Prechtl gives the following as the order in which the metals
stand in this respect :*
TABLE IXa.
MALLEABILITY.
DUCTILITY.
Hammered.
Rolled.
Wire-drawn.
i. Lead,
Gold,
Platinum,
2. Tin,
Silver,
Silver,
3. Gold,
Copper,
Iron,
4. Zinc,
5. Silver,
Tin,
Lead,
Copper,
Gold,
6. Copper,
7. Platinum,
Zinc,
Platinum,
Zinc,
Tin,
8. Iron.
Iron.
Lead.
Authorities differ, however, in their statements in regard to
the order of the metals in these respects, and the preceding
figures as given in tables are often quoted from Regnault.f
Encyclopaedia Britannica.
f Regnault's Chemistry.
3O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
22. The following table of the principal metals and theil
properties is extracted from Watts :*
TABLE X.
CHARACTERISTICS OF METALS.
NAME.
DATE OF
DISCOVERY.
NAME OF
DISCOVERER.
S. G.
SP. HEAT.
MELTING
POJNT.
CONDUC-
TIVITY.
Water = i.
Ther-
mal.
Elect.
Platinum . . .
Iridium ....
Gold .
1741
1803
Wood
21.5
21.15
19.26
15.60
11.80
11-33
10-57
9.80
8.94
8.82
8.02
7.84
7.30
7-13
6.72
2.56
1.74
0.0324
0.0326
0.0324
0.0319
0.0593
0.0314
0.0570
0.0308
0.0952
0.1086
O.I2I7
O.II38
0.0562
0.0955
0.0508
0.2143
0.2499
8.4
18.
Descotils ...
1200° C. (?)
— 39° C...
53-2
78.
Mercury. ...
Palladium . .
Lead
1803
Wollaston
6.3
8-5
100
1.8
73-5
18.4
8.3
100
1.2
99.9
I3-I
332° c...
1000° C...
270° C...
1200° C. (?)
Silver
Bismuth. . . .
Copper. .
Nickel
Manganese. .
1751
1774
Cronstedt
Gahn ; Scheele.
2000° C. (?)
11.9
14-5
16.8
12.4
29.
4.6
56.1
41.2
Tin
,
Zinc
4^° C
Antimony
Aluminium. .
Magnesium .
1828
1829
Wohler
4.1.1° C. .
23. Crystallization is always observed in metal when de-
posited from solution or when solidifying from fusion when the
conditions are favorable. Gold, silver, copper, antimony and
bismuth, and many alloys, as those of copper and of iron, are
found in crystalline form in nature. Deposition by the vol-
taic current often produces very large and perfect crystals.
Lead is precipitated from solutions in beautiful crystalline
forms when displaced by zinc. Iron forms well-defined crys-
tals when kept heated at nearly the temperature of fusion for
a considerable time, and is supposed by some authorities
to take on the cubic form when exposed to severe and
long-continued jarring. This tendency to crystallization is
* Dictionary of Chemistry ; Lond., 1868 ; vol. iii, ; p. 936.
QUALITIES OF THE METALS AND THEIR ALLOYS. 3?
increased by the presence of manganese or of phosphorus.
Zinc, in the ingot, is often very distinctly crystalline*
The precious metals, aluminium, cobalt, copper, iron, lead
and nickel are so nearly amorphous, or if crystalline in struct-
ure in their ordinary state, have such small and uniform crys-
tals that they may be considered compact and homogeneous.
Antimony, bismuth, manganese, and zinc, and some of their
alloys often exhibit distinct crystallization, which may also
be produced in all metals by prolonged heating or slow cool-
ing, and, as supposed by some observers, by long-continued
vibration or jarring.
24. Specific Heats. — The effect of heat upon metallic sub-
stances in the production of changes of volume and of tem-
perature varies considerably.
The Specific Heats of a number are given in Table XL;
they measure in thermal units the quantity of heat required
to change the temperature of a pound or a kilogramme of the
metal one degree.
TABLE XI.
SPECIFIC HEATS OF METALS.
SPECIFIC
HEAT. ,
AUTHORITY.
.n^S
Regnault.
«' 32 — 212 F
.1008
Dulong & Petit.
" *?2 — 3Q2 F. . ,
.1150
«i
" 12 — 572 F. . ,
.1218 ,
«
« 32 — 662 F
. 1255
«
Cast iron
.1298
Regnault.
Steel, soft
.1165
. IJ75
ti
.00515
n
" 32 — 212 F
.0027
Dulong & Petit
" 32 — 572 F. .
.1013
Cobatt
.10696
Regnault.
.11714
Nickel
. 1086
tt
.IIIQ
tt
.O56q5
it
0^62^
tt
Zinc
•OQ555
tt
• OQ27
Dulong & Petit
*' 32 — 572 F . .
.1015
32 MATERIALS OF ENGINEERING-NON-FERROUS METALS.
TABLE XI.— Continued.
SPECIFIC
HEAT.
AUTHORITY.
Brass
.OQ^Q
Regnault.
Lead
O3I4
O7241
<«
32 — 212 F
QTOC
Dulong & Petit»
Q'lAT.A
Pouillet.
0^518
" 1832 F
.03718
it
" 2192 F
.03818
u
Mercury, solid ..
OTTQ
Resfnault.
.Oq-^^2
' 32 — 212 F . . .
O^T
Dulong & Petit.
' 02 — C72 F.
.O'le
«
.0^077
Regnault.
" "32 — ^72 F
QS.A"]
Dulong & Petit.
•)4<
.O^O04
Regnault.
Gold
.O3244
Silver
O^7OI
<«
,O6lI
Dulong & Petit.
Manganese . .
I 11 II
Regnault.
Iridium •
.1887
.Ol6^6
«
The following table exhibits the relationship between the
combining numbers and specific heats of the metals; the
product of specific heat and of combining number is seen
to be very nearly constant, as shown by Kopp, who also makes
this product, or the ** atomic specific heat," 6.4 for 42 ele-
ments, including all in this table. Kopp also verifies the
law of Woestyn and Gamier, finding the specific heat of the
molecule equal to the sum of the specific heats of the con-
stituent atoms.
QUALITIES OF. THE METALS AND THEIR ALLOYS. 33
TABLE XLz.
SPECIFIC HEATS AND COMBINING NUMBERS.
METALS.
COMBINING
NUMBERS.
SPECIFIC HEAT
(REGNAULT).
PRODUCT
27
0.2143
5-8
122
0.0508
6.1
75
0.0814
6.1
2IO
o . 0308
6.5
112
0.0567
6.3
63.5
0.0951
6.0
Gold
196
0.0324
6.4
Lead
207
0.0314
6.4
56
o. 1138
6.1
Magnesium •
24
0.2400
6.0
55
0.1217
6.7
200
0.325
6.5
Nickel
5Q
0.1089
6.4
106
0.0593
6.3
107.6
0.0329
6.5
30. 1
o. 1695
6.5
108
0.0570
6.2
Sodium
2^
0.2934
6.7
Tin
118
0.0562
6.6
65
0.0956
6.2
The specific heats are slightly variable with change of tem-
perature. This change has been carefully studied only in a few
cases. Holman deduces,* by collating results of experiments
published by known authorities, for the specific heat of iron :
k = 0.10687 +
k = 0.10687 + 0.0000547^ + 0.0000000428^
32) + 0.0000000238(/ — 32)2
(I)
for the Fahrenheit and Centigrade scales respectively.
For platinum he obtains :
k = 0.0328 + o.ooooo3022(/ — 32) + 0.000000000009 (t — 32)2,
k = 0.0328 + 0.00000544^ + o.ooooooooooi6/f2,
or, very nearly,
k = 0.03208 + 0.00000304 (t— 32) )
k — 0.03208 + 0.00000547^ J"
(2*
* Journal Franklin Institute, August, 1882.
34 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The figures given in Table XI. are mean values be-
tween the temperatures of freezing and of boiling, of the
quantity of heat, in thermal units, required to produce a
change of temperature of one degree. Their values have
been shown by Dulong and Petit to increase with the rise of
temperature, as does the specific heat of water itself. When
melted their specific heats are greater than when solid.
The specific heats represent the number of units of water
which would be raised in temperature one degree by the
addition of the amount of heat which would raise one unit of
weight of the metal one degree. Specific heat is sometimes
called " Capacity for heat."
25. The Expansion of the Metals by increase of tern-
perature is exhibited by the following table of coefficients of
linear expansion.
The figures represent the extension, in parts of its own
length, of a bar of the given metal during a rise in tempera-
ture from the freezing to the boiling point of water.
TABLE XII.
LINEAR EXPANSIONS OF SOLIDS.
EXPANSION BETWEEN
32°F.(0° C.) AND 2I2*F.(lOO°C.)
AUTHORITY.
Glass
0.000872 to 0.000918
Lavoisier and Laplace.
0.000776 to 0.000808
Roy and Ramsden.
Copper
o 001712 to o 001722
Brass
o 001867 to o 001890
.< «
«
o 001855 to o 001895
Roy and Ramsden
Iron
O.OOI22O to O.OOI235
Lavoisisr and Laplace.
Steel (untempered) , . .
1 ' (tempered)
0.001079 to 0.001080
o 001240
« < t
Cast Iron
0.001109
Roy and Ramsden.
Lead
o 002849
Lavoisier and Laplace
Tin
0.001938 to 0.002173
« n
o 001909 to o 001910
« «
Gold
0.001466 to 0.001552
« M
o 000884 .
Dulong and Petit.
Daniell
QUALITIES OF THE METALS AND THEIR ALLOYS. 35
Chancy gives* the following values of the coefficients of
linear expansion, at ordinary temperature, as recalculated by
him, and corrected for the author, from selected data, for the
Standards Office of the British Board of Trade.
TABLE XILz.
EXPANSIONS OF SOLIDS.
FOR i° F.
FOR i° C.
AUTHORITY.
Aluminium cast .... . .
0.00001234
O.OOOO222I
Fizeau
0.00000627
O.OOOOII29
1C
0.00000957
O.OOOOI722
Sheepshanks
" plate
0.00001052
o 00001894
Ramsden
" sheet
o . 00000306
O.OOOOO55O
Kater
Bronze, Baileys,
Cop., 17 ; tin, 25 ; zinc, i.
Same . .
0.00000986
O.OOOOOQ7<
0.00001774
O.OOOOI775
Clarke.
Hilgard
Copper
O.OOOOO887
0.00001596
Fizeau
Gold
0.00000786
O.OOOOI4I5
Chandler & Roberts.
Indium ...
o 00000356
o 00000641
Fizeau
Lead .
0.00001571
0.00002828
«
Mercury (cubic expan.)
O.OOOOqq84
O.OOOI797I
Regnault & Miller.
Nickel
0.00004695
0.00001251
Fizeau.
Osmium . . .
o 00000317
O.OOOOO57O
ti
Palladium
o 00000556
O.OOOOIOOO
Wollaston.
0.00001129
0.00002033
Daniell.
Platinum .
o 00000479
o . 00000863
Fizeau
" 90 ; iridium, 10. . . .
" 85; " 15....
Silver
0.00000476
0.00000453
0.00001079
0.00000857
0.00000815
0.00001943
«
Chandler & Roberts.
Tin
0.00001163
o . 00002094
Fizeau
0.00001407
0.00002532
Baeyer
" 8 tin I
0.00001496
0.00002692
Smeaton.
These coefficients are not absolutely constant, but vary
with the physical conditions of the metals. They are not the
same with the same material in its forms of cast, rolled, ham-
mered, hardened, or annealed metal. The value of the co-
efficient of expansion also increases slightly with increase of
temperature.
To determine the length, Lr, of a bar at any given tem-
perature, /', knowing its length, L, at any other temperature,
/, we have the formulas :
* Calculations of densities and expansions ; report by the Board of Trade I
printed for the House of Commons, London, 1883.
36 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
at
T8o
at'
100
, for Fahr. scale, . .
_
100
, for Cent, scale,
(3)
(4)
where a is the coefficient given above.
TABLE XIII.
EXPANSIONS OF VOLUME.
PER DEGREE CENT.*
o° C. (32° F.) to
100° C. (212° F.).
Glass
.00002 to .00003
.002 to .003
.000035 to .000044 :
.0035 to .0044
Copper .
.000052 to .000057
.0052 to .0057
.000026 to .000029
.0026 to .0029
Lead
.000084 to .000089
.0084 to .0089
Tin
.000058 to 000069
.0059 to .0069
Zinc
.000087 to .000090
.0087 to .0090
Brass
.000053 to 000056
.0053 to .0056
Steel
.000032 to .000042
.0032 to .0042
.000033
.0033
These results are partly from direct observation, and
partly calculated from observed linear expansion, which is
one-third the cubical expansion.
26. The Fusibility of the Metals, or their property of be-
coming liquid at a temperature which is always the same for
the same metal, is a quality which has an important bearing
upon their useful applications in the arts.
All solids which do not undergo decomposition by heat
before reaching that temperature have definite " melting
points."
The metals differ more widely in their temperatures of
* Abridged from Watts's "Dictionary of Chemistry."
QUALITIES OF THE METALS AND THEIR ALLOYS.
fusion than even in density. Solidified mercury melts at
nearly 40° below zero, Fahr. (—40° Cent.); while platinum
requires the highest temperature attainable with the oxy-
hydrogen blow-pipe. The more common metals fuse at tem-
peratures quite readily attainable, although none of them
melt at temperatures approaching those ordinarily met with
in nature.
Some of the metals may even be readily volatilized, and
probably all are vaporized, to a slight degree at least, at very
high temperatures. Mercury boils at 330° Cent. (626° Fahr.).
Zinc can be distilled at a bright red heat, and copper and
gold are known to give off minute quantities of vapor at
temperatures frequently occurring during the process of man-
ufacture.
The low temperatures of fusion of tin, lead, bismuth, and
antimony, allow of their being readily applied as solders,
either alloyed or separately. Cast iron, copper and its alloys,
and other metals, melt at temperatures which are easily
reached, and the iron and the brass founders are thus enabled
by the process of moulding and casting, to produce the most
intricate forms readily and cheaply, and thus, when desired,
to obtain large numbers of precise copies of the same pattern.
The melting points of some of the more important metals
are as follows :
TABLE XIV.
TEMPERATURE OF FUSION OF COMMERCIAL METALS.
FAHR.
CENT.
-3Q°
-39°
Tin
4.2O
216
Bismuth
4.QO
254
Lead
6^O
W2
Zinc
700
371
Silver
1,280
6cn
Brass
1,870
I,O2I
2,550
1,1x8
Cast Iron . .
2 7*0
I, CIQ
4,OOO (?)
2.2OI O
38 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The temperatures of fusion of pure iron, or of wrought
iron, are very high, and are not precisely known, no means
of accurate measurement having yet been applied to their
determination.
The following very complete table will serve for reference
in more extended work.*
TABLE XV.
MELTING POINTS OF PURE METALS.
FUSIBLE ABOVE RED HEAT.
FUSIBLE BELOW RED HEAT.
F.
C.
F.
C.
Silver • • • • • . . •
. + 1873°
1996
2016
2786
? Highes
the f
Do not me
for^
Fusible
Oxyhyc
flan
+ 1023°
1091
1 102
153° •
t heat of
Drge.
It in the
Je-
only in
rogen
le.
Mercury
-39°
+ 101.3
144-5
207.7
356
442
442.5
497
56i
617
6i5 (?)
773
red
-39°. 8
+ 38.5
62.5
97.6
1 80
227.8
228
259
294
325
3*4
412
heat
Gold . .
Cast Iron
Pure Iron,
Nickel,
Cobalt,
Manganese,
Palladium,
Molybdenum,
Uranium,
Tungsten,
Chromium,
Titanium,
Cerium,
Osmium,
Iridium,
Rhodium,
Platinum,
Tantalum,
Lithium • . • • .
Tin
Cadmium
Bismuth
Thallium
Lead
Latent Heat. — In passing from the solid to the liquid
state, a certain amount of heat disappears, being expended
in producing this change of physical conditions.
Latent Heat, as this is called, varies in amount with dif*
* For approximate values of temperatures of fusion of alloys, see later.
QUALITIES OF THE METALS AND THEIR ALLOYS. 30
ferent substances. In Table XVI. are the latent heats of
several, as obtained by M. Person, expressed in thermal units.*
TABLE XVI.
LATENT HEATS OF METALS.
CENT.
FAHR.
Tin
14.25
25-65
12.64
22.75
Lead
C . 07
9.67
Water
70. 25
r
142.65
Silver
21 O7
•17 oq
Cadmium .
n.66
24.. 5Q
27. Chemical Character. — Chemically, the metals exhibit
the same variation of properties as physically, and the line of
demarcation between the metals and the metalloids is no
more definitely fixed. They are acid or basic in combination,
and resemble the metalloids more or less nearly in chemical
action, according to the proportion as well as the nature of
the elements with which they combine. Their oxides are
usually basic, but often acid. The alkaline metals unite with
oxygen with great rapidity to form alkaline oxides ; the com-
mon " useful " metals are oxidized readily, but less freely
than the preceding, and gold, silver, platinum, and others,
have little affinity for oxygen, and do not easily corrode.
Nearly all metals combine freely with sulphur, and their
sulphides form, in some cases, extensive deposits which are
worked for the market.
28. Alloys are formed by fusing together two or more
metals. In the alloys, metallic qualities and chemical prop-
erties are not always completely altered or masked, as is
the case in chemical combinations with the non-metals.
* This thermal unit is the quantity of heat required to raise the temperature
of unity in weight of water at maximum density, one degree in temperature.
For values of constants, relating to the non-ferrous metals, expressed in ' * C. G»
S." units, see Appendix, Part I.
40 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The physical properties of the alloys are, however, some-
times quite different from those of the constituent metals,
notwithstanding the fact that the compounds formed are
apparently not definite, as in cases of purely chemical combi-
nations. It would appear probable that the force of chemi-
cal affinity performs some part in the formation of the alloy.
It is not improbable that a definite compound is usually
formed which either dissolves, or is dissolved in, any excess
of either constituent which may be present.
Examples of alloys are seen, in gold and silver coins, in
which the precious metals are hardened by alloying them
with copper, to give them greater durability. Copper is too
soft and tough to allow of its being conveniently worked, and
it is, therefore, for most purposes, alloyed with tin or zinc, and
these alloys — bronze and brass — are, by varying the propor-
tions of the metals used, adapted to a wide range of useful
application. Alloys of copper and tin exhibit strikingly the
fact, noted above, that the alloy may have widely different
properties from either constituent.
Speculum metal is composed of 33 per cent, of tin fused
with 67 per cent, of copper. Its color is nearly white, it is
extremely hard, exceedingly brittle, and takes a magnificent
polish. The latter property gives it value for reflectors of
telescopes. Its metallic lustre resembles neither of its con-
stituents, and its tenacity is but about 20 per cent, of that of
the weaker metal.
Type metal, also, formed by alloying lead and antimony,
in the proportions of four of the former and one of the latter,
is a hard alloy, capable of being cast in moulds, taking form
very perfectly, and it differs greatly in its properties from
either lead or antimony.
It is usually found that the temperature of fusion of an
alloy is below, and often considerably below, that of either
constituent metal. The strength of alloys is often greater
than that of the metals composing them.
The characteristics of the alloys will be discussed at
greater length when treating of those compounds hereafter.
The minimum percentage of metal in paying ores varies
QUALITIES OF THE METALS AND THEIR ALLOYS. 4!
with the value of the metal in the market, and the cost of
reduction and transportation ; the following may be taken as
fair averages :
Iron 25 to 40 per cent.
Lead 201025 "
Zinc 201025 "
Antimony 201025 "
Copper f. 2 to 2.5 "
Tin I to 1.5 "
Mercury I to 2.5 "
Silver 0.0005 to o.ooio per cent
Platinum o.oooi to 0.0002 "
Gold o.oooooi too.ooooi '*
Where two metals exist together, as copper and silver;
lead and silver, iron and manganese, the ore may be reduced
for the one, and the other obtained incidentally, at less
expense, when in even smaller quantities than above given.
CHAPTER II.
COPPER, TIN, ZINC, LEAD, ANTIMONY, BISMUTH, NICKEL,
ALUMINIUM, ETC.
29. Copper (Latin Cuprum, Cu.) has been known to man-
kind from some very early, and even prehistoric, period, and
was applied in the manufacture of tools and useful implements,
probably long before iron was used, or even known. It exists
native and is comparatively easily reduced from its ores and
worked, and hence could be obtained and worked at a
time when the art of reducing the comparatively refractory
ores of iron had not been acquired.
Tubal Cain worked " in brass and in iron " ; the ancient
Egyptians mined copper in the neighborhood of Sinai, and of
it made an alloy which was used in making their mining and
quarrying tools and are supposed by Wilkinson and other
Egyptologists, to have been able to temper it as we temper
steel. It is more likely, however, that they knew only how
to produce and harden the alloys of copper and tin.
All the more civilized nations succeeding those contempo-
rary with Cheops used bronze extensively in making statuary
and monuments, and the Greeks and Romans made a statuary
bronze, taking a " patina " unexcelled in later times. Their
foundry-work was fully equal to that of the moderns. It was
also used in coinage by these nations as it is used to-day.
The prehistoric nations of America used large quantities
of copper, quarrying it in all those districts in the neighbor-
hood of Lake Superior which have been recently worked for
mass copper, and their tools are still occasionally found in
the old workings. It was worked in Mexico by the Aztecs,
and by the same race in Chili and Peru, before the discovery
COPPER. 43
of those countries by the Spaniards. The bronze used by the
Aztecs was of similar composition to that made by their
Asiatic contemporaries, and that used frequently in modern
times when a tough, as well as strong, bronze is desired — 94
per cent, copper, 6 per cent. tin. Bronze implements of
great age have been found in all parts of Europe, and so ex-
tensively was it used in the period preceding that in which
iron became common that that period has been denominated
the " Bronze Age."
According to Lubbock,* copper was mined in many locali-
ties, and the knowledge of mining, alloying it and of casting in
bronze was brought into Europe from the East. The tin
with which it was alloyed was obtained, in the time of the
Phoenicians, from Cornwall. The forms of the bronze im-
plements found in Europe and in America are often strikingly
similar. Bancroft f states that the American Indians were
reported by Cabot, in 1598, to be familiar with this metal and
its use.
30. Qualities. — The metal has a deep red color, the only
metal as yet known having that color, is heavy (S. G. 8.8 to
8.93), very malleable and ductile and has considerable tenacity.
Its hardness is usually rated at 2.5 or 3. When warm, and
when rubbed with the hand, it gives out a strong odor of a
peculiar and somewhat disagreeable character. Commercial
copper is contaminated with silver, lead, antimony and iron ;
although the native copper, as much of that obtained from
Lake Superior, is sometimes almost chemically pure.
The melting point of copper is given by Pouillet as 2050°
Fahr. (1121° C.) and vaporization occurs at the white heat,
the vapors burning with the green flame which gives the
characteristic lines of this metal in the spectroscope. It
is a remarkably good conductor both of heat and electricity.
Copper does not oxidize in dry air at ordinary temperatures,
but does so rapidly in a moist or acid atmosphere, and at
temperatures approaching the red heat.
Of this metal from 225,000 to 250,000 tons are annually
* " Prehistoric Times." fVol. i. p. 12 (Ed. 1856.)
44 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
consumed, principally from the United States, Cornwall,
Chili and Bolivia. It is supplied in the form of bars, wire,
sheet and ingots, which latter are re-melted to obtain copper
and alloys in castings. It is, next to iron, the most important
and useful of the metals. Its valuable properties will be de-
scribed at greater length, presently.
31. Copper Ores are distributed very widely over the
earth's surface and are found in every large political division
of the world. It exists in a great variety of forms, usually as
sulphide or oxide; but in some cases, as in the United States,
on the south shore of Lake Superior, is found in the form of
native copper and in enormous quantities. Very large quan-
tities are now mined in Montana, Arizona, and other western
districts.
Metallic copper occurs in masses, in flakes and sheets, in
threads, and in spongy masses dissemimated through rock
crevices, earthy gangue or even solid rock masses. Enor-
mous blocks and extensive masses are found and worked in
several of the mines of Lake Superior. These great blocks
sometimes weigh several hundred tons. In this condition it
is one of the most expensive ores of copper ; for the metal is
excessively tough, and cannot be blasted, but must be pre-
pared for the market by being cut up with tools ; and the
presence of siliceous gangue in the mass renders this opera-
tion very difficult. In the deposits worked in and near the
Calumet and Hecla mine of that district, it exists in the red
conglomerate in a peculiar form, permeating the rock very
uniformly in just such a proportion as gives maximum ease
and cheapness of mining and preparation.
The metallurgists find that comparatively few of the cop-
per minerals are of much importance, by far the largest pro-
portion of this metal annually produced by the mines of the
world being obtained from copper pyrites.
Phillips gives the following list of the commercial ores of
copper.*
Native Copper is cubical, occurs crystallized in octahedrons,
sometimes modified, lamellar, filiform, or arborescent, and has
a specific gravity — 8.83. No known locality produces such
* Vide " Elements of Metallurgy ;" J. A. Phillips. Lond., 1874.
COPPER ORES. 45
large quantities as the region of Lake Superior, where it occurs
in veins intersecting trap rocks, frequently associated with
metallic silver. In small quantities, native copper is of fre-
quent occurrence, but except in the region above mentioned,
it is not of much importance as an ore. It is generally re-
markable for great toughness.
Cuprite (red oxide of copper) — composition, Cu.2O — is cub-
ical, generally in cubes and octahedrons, of a ruby-red color,
with a specific gravity — 6, and contains, when pure, 88. 80
per cent, of copper.
Melaconite (black oxide of copper) — composition, CuO — is
cubical ; rarely found crystallized, but more commonly
earthy ; is massive, or pulverulent, affording, when pure,
79.82 per cent, of copper.
Malachite (green carbonate of copper) crystallizes in the
oblique system, the crystals being often very complicated ;
occurs more frequently massive or incrusting the surface,
being botryoidal or stalactitic. The specific gravity = 3.7 to
4.1. Its composition is CuCO3, CuH2O2, yielding, when pure,
57-33 Per cent, of copper. This mineral frequently occurs
near the surface, in veins producing sulphides and other ores
of copper, and has probably been derived therefrom by at-
mospheric agencies.
Azurite(b\ue carbonate of copper) — composition, 2CuCO3,
CuH2O2 — crystallizes according to the oblique system, and
also occurs massive. Its specific gravity is 3.5 to 8.81 ; con-
taining, when pure, 55.16 per cent, of metallic copper. It
occurs largely in South Australia, and formerly at Chessy,
near Lyons ; and is hence sometimes called Chessylite.
Chalcopyrite (copper pyrites) — composition, Cu2S, Fe2S3 — is
prismatic, often in hemihedral forms, though more commonly
massive, with specific gravity = 4.2 ; containing, when pure,
34.81 per cent, of copper. This, which is the most important
ore, rarely contains, as sent to market, more than 12 per cent.
of that metal, and frequently less.
Bornite (purple copper ore) crystallizes in the cubical system,
and has a specific gravity 4.4 to 5.5. Its composition varies,
sometimes 3Cu2S, Fe2S3 ; copper from 50 to 70 per cent.
46 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Chalcocite (gray sulphide of copper) is prismatic, and of
specific gravity 5. 7; its composition is Cu2S, yielding, when
pure, 79.70 per cent, of copper.
The copper sent into the market from the Lake Superior
district is principally derived from crushed low-grade rock,
containing native copper ; that coming from the southern
Rocky Mountains is derived from oxides, and that from the
Butte district of Montana and from Arizona is obtained from
argentiferous ores. The copper smelted in the Appalachian
sections is from pyritous ores. Altogether they yield about
200,000 or 300,000 tons annually. The output in 1845 was
but 100 tons,* that in 1899 was about 600 millions of pounds
(nearly 325,000,000 kilogs.), valued at 15 cents per pound, or
over $50,000,000, and was increasing at the rate of 10 to 15
per cent, annually. Much of this product is exported. The
refining is done in works situated at Baltimore, Md., Orford,
N. Y., and in various other scattered localities in the United
States, as well as by the mining companies.
The production of Great Britain is very small, and that of
Spain and Chili is enormously great.
Copper smelting in the United States is conducted, by
three principal methods, according to the character of the
ores. These are : f
Fusion of native copper and refining ;
Fusion of carbonates and refining ;
Reduction of sulphuretted ores and refining.
Lake Superior copper is of the first class. It is melted
down as received with its gangue and with 6 or 8 per cent,
limestone and 10 per cent, refinery slags. The charges are
about 12 tons each, which are worked in a large reverberatory
furnace about 12 hours. The slags are skimmed and the
richer grades are refined, while the remainder form a part of
the next charge. The refining and ladling take 5 hours.
Cupola furnaces are sometimes used, which take 20 tons at
a run, of which 40 or 45 per cent, is limestone, 30 to 35 per
* " Metallic Wealth of the U. S." : Whitney.
\ J. Douglas, Jr., in " Mineral Resources of the U. S." Gov't Print. (GeoL
Survey ; Interior Dept.), Washington, D.C., 1883.
REDUCTION OF COPPER ORES. 47
cent, anthracite coal and 4 per cent, copper. The lining fur.
nishes a considerable amount of silica and is rapidly cut out.
The Bessemer process is also used in reducing copper.
32, The Processes of Reduction of copper ores differ with
their composition. The oxides and carbonates are easily re-
duced, by fusion, in presence of carbon, with a siliceous flux.
The copper is promptly reduced to the metallic state. Some
loss is usually met with in consequence of the tendency of
the oxide to form a silicate, and this is checked by supplying
either an alkaline base, usually lime, or by mixing with sul-
phuretted ores, of which the sulphur unites with the oxygen
present and thus permits complete reduction.
The sulphides are usually first roasted and thus converted
to a considerable extent into oxide. This roasted ore is then
smelted, sometimes in reverberatory and sometimes in blast
furnaces, and this roasting and smelting is repeated until
a " regulus " is obtained consisting of a nearly pure sulphide.
This product is finally roasted with free access of air until,
having been brought to a certain state, in which sulphide and
oxide exist in the right proportion, a double decomposition
occurs, yielding sulphurous acid and metallic copper (2CuS-|-
Cu2O = SO2 + Cu6) which latter is of fair degree of purity, and
is known either as "coarse copper," or " blister copper," etc.,
etc. This is finally purified before it is sent into the market
as ingot copper. The final process consists in melting down
in the presence of an oxidizing flame and with fluxes, and,
after removal of slag, " poling " or stirring with birch poles.
This last process of refining is the only one necessary in the
treatment of the native copper of Lake Superior. Argen-
tiferous ores, as those of Montana, are now extensively re-
duced by electrolytic methods, electric currents of enormous
volume being supplied by dynamos of large capacity. Gold
and silver are in some instances thus produced in consider-
able quantity as a " by-product " and at no important expense,
33. Details of Reduction of Copper Ores. — In detail,
these processes arc very complex, although sufficiently simple
in their theory. The process of reduction usually practised
consists of roasting to expel sulphur and arsenic, melting to
48 MATERIALS OF ENGINEERING— NON-FERROUS METALS-
flux out iron oxide by siliceous fluxes, and roasting and smelt-
ing in one operation to obtain the commercial metal.
The first operation is that of breaking up the ore into small
and, as nearly as may be, uniform pieces, removing useless
gangue and assorting the ore in such a manner as to facilitate
the processes of reduction. The next process is that of cal-
cining, roasting, about three tons at a time, in a reverberatory
furnace on a long and wide level hearth — often 15 or 16 feet by
12 or 14(4.6 or 4.9 metres by 3.7 or 4.3) — where it is spread in
a thin layer and exposed to the action of the flame. The
hearth is bricked over and cemented with fire-clay and the
roof is a low arch. Openings from the fire-place admit the
heating gases ; others from the atmosphere provide for oxida-
tion by the admission of air ; and others at each side are
arranged for the discharge of the roasted ore into a low
arched space, or chamber, under the furnace. The ore is
admitted through openings in the top surmounted by hop-
pers, into which it is filled and left to heat gradually until
dropped into the furnace.
The fuel, a soft coal or a mixture of bituminous and semi-
bituminous coal, is burned with restricted air-supply, and the
resulting carbonic oxide passes into the furnace, where, meet-
ing the required air, it burns to carbon dioxide, and the long
flame sweeping over the hearth, heats the ore to the tempera-
ture needed to roast it. While thus exposed to the heat of
the burning gas, the ore is continually stirred and raked over
to bring all parts of the charge into contact with the flame.
During this process, any sulphur present is exposed to
oxygen at high temperature, and a part, but never all, is
oxidized, passing off as sulphurous acid ; or oxidizing in small
amount still further, it unites with the copper to form a sul-
phate. The arsenic passes off as white arsenic, arsenious
acid, in the form of vapor. The copper also combines, to a
slight extent, with oxygen, to form the suboxide of copper,
and any salt of iron present in sulphides becomes changed
to oxide.
In some cases, the roasting is accomplished by indirect
heating and out of contact with the flame from the grate.
REDUCTION OF COPPER ORES. 49
and the vapors thus isolated are diverted for the purpose of
converting the sulphurous acid into sulphuric acid, which
latter is collected in the usual way in leaden chambers.
Where the gases from the fuel mingle with the vapors of
sulphur, and other products of roasting, they are often all
carried into a " condenser," in which a spray of water is
introduced to wash the air clean before discharging it into
the atmosphere.
The ore is now ready to be smelted. If any ores are to
be treated which are free from arsenic and sulphur, they are
not roasted, but are mixed with the other ores after the latter
are calcined, and the mixture is then smelted.
The smelting furnace, called often the " ore furnace," is a
small reverberatory furnace, fitted with a comparatively large
grate, and having a hearth so formed that the molten ore
may lie on it in a shallow pool, deepest near the middle of
one side of the furnace. The charge is about one and a half
tons of ore, flux and slag derived from a later operation, of
which the ore amounts to about two-thirds, while the flux
and slags make up the other third. This being charged upon
the bed of the furnace, the slag soon melts, and the whole
charge later becomes molten and " boils " rapidly with disen-
gagement of sulphurous acid. In the course of four hours,
or less, the attendant uses his rubble, stirring the charge
thoroughly, and at the same time raising the heat of the
furnace until the coarse metal and slag separate. When this
is done, the " matt " or " regulus " of partly refined or
"coarse metal" is tapped off into a cast-iron box having a
perforated bottom, through which it runs into a tank contain-
ing water, and thus becomes granulated. The slag is run
into moulds, and the blocks so formed — of silicate of iron,
principally — are useful in building.
The regulus is only one-third copper, the rest being sul-
phur and iron, and the whole being a sulphide of copper and
iron. It is charged again into the roasting furnace, and
calcined for twenty-four hours, the workmen raking it over
en or twelve times in the interval, as the sulphur burns out
of the more exposed portions. The loss of about one-half the
$O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
sulphur reduces the charge to a mixture of iron oxide, copper
sulphide, and some iron sulphide.
This calcined regulus is then charged with slags from
later processes in equal or greater quantity, and with any
pure oxides or carbonates at hand, into a melting furnace,
and there held in fusion about six hours, when the resulting
regulus and slag are tapped off. The former may be run
into water as before, and thus made " fine metal," or cast in
pigs as " blue metal,'* containing about seventy-five per cent,
of copper. The best copper is found in the pigs last cast,
the first producing a less pure metal called, later, " bottoms."
or " tile copper." When less rich in copper, it is again cal-
cined and melted to obtain block or coarse copper, contain-
ing more metal. The slag, or " metal slag," as it is called,
contains, usually, enough of copper to make it advisable
to re-work it with the ores, as already described, or sepa-
rately.
Still another repetition of the calcining and melting proc-
esses removes a part of the remaining sulphur, and yields
what is called " blistered copper ; " the " blisters " on the
surface of the ingots giving evidence of the escape of sul-
phurous acid while solidifying.
Finally, this blistered copper is re-heated in charges of six
or eight tons weight, with free access of air, and the arsenic and
sulphur remaining are converted into arsenious and sulphur-
ous acid, and the iron, lead, tin, and other oxidizable impuri-
ties are converted into oxides before the charge is allowed
to melt, this preliminary operation occupying about six
hours. The metal is then melted down and sampled to
determine how the process of "toughening" shall be con-
ducted. This consists in " poling," or stirring the molten
charge with poles, from young saplings of birch, usually,
until sample ingots exhibit the density, toughness, fineness
of grain, and pure copper color which indicate the desired
quality. When right, or at " tough-pitch," it is run into
ingot moulds and becomes "tough-cake." The process of
poling results in the removal of the oxygen taken up by the
copper in the earlier processes by contact with the hydro-
REDUCTION OF COPPER ORES. 5 1
carbons and the pure carbon of the wood. Overpoling causes
the absorption of bismuth, and gives the same brittleness
which had been caused by oxygen ; and the avidity with
which copper takes up both these elements makes this opera-
tion one demanding great care and skill.
Where sheet copper is to be made, lead is often added
before casting, to give greater malleability, by fluxing out
the tin and other alloy ; this lead is oxidized, and is all
removed again with other oxides in the slag.
Modifications of this process are adopted with leaner
ores ; and the melting and poling only is necessary with pure
native copper, such as is mined in the Lake Superior region
in the United States.
Copper is reduced at Ore Knob, N. C., from very pure
but lean ores, containing from two to five per cent, copper.
These ores are picked over carefully, and sent to the calcin-
ing ground, where they are roasted in heaps, under sheds 240
to 300 feet long and 34 feet wide, the piles measuring TOO
tons of fresh, or 50 tons of roasted ore. The roasted ore
contains four to five per cent, copper.
Fusion of the ores takes place in furnaces resembling
cupolas, and the mattes are smelted in the same kind of fur-
nace. The latter contain twenty or twenty-five per cent,
copper. These " single mattes " are roasted in heaps, and
fused in shaft-furnaces for black, or pig copper, and " double,"
or concentrated mattes. This black copper contains ninety
to ninety-five per cent, metallic copper, some iron, and other
elements.
The mattes are re-worked, and the crude copper is refined
in reverberatory furnaces, taking five tons at a charge ; the
product consists of 99.8 per cent, metallic copper.
The wet processes of copper extraction are divided by
Hunt * into three classes :
I. Those in which the copper in sulphuretted ores is ren.
dered soluble in water, after roasting them, converting them
into chlorides or sulphates.
II. Those in which free hydrochloric or sulphuric acid is
* Trans. Am. Inst. Min. Engineers, vol. x., p. n.
52 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
used to dissolve the metal from oxides or roasted ores. These
are usually costly processes, and are seldom practised.
III. A method by which a hot solution of ferrous chloride
with common salt is used to convert copper oxides into chlo-
rides. This is the Hunt and Douglas method.
The Hunt and Douglas process of extracting copper from
its ores consists, as practised in North Carolina and in Chili,
in the dissolving of the oxides in a hot solution of proto-
chloride of iron and common salt, thus converting the proto-
chloride into peroxide of iron, and the oxide of copper into
protochloride and dichloride, the latter of which is soluble in
strong brine. From this solution the copper is precipitated
by the introduction of scrap iron. This method involves
almost no consumption of chemicals other than common salt,
which is added to supply unavoidable losses. The sulphur-
ous ores are converted into oxides by crushing, grinding,
and calcination in three-hearthed reverberatory furnaces.
The iron consumed amounts to seventy per cent, of the
copper reduced as cement copper. One furnace roasts two
and a half to three tons of ore per day, using one-third cord
of wood.
Special cases. — Carbonate ores sometimes supply excel-
lent copper, although rarely, if ever, equal to that found
native. They are now smelted in cupola furnaces, in which
the parts exposed to highest temperature are surrounded and
cooled by water-jackets. These furnaces are capable of smelt-
ing 50 tons per day. Oxides are similarly smelted, using about
I ton of fuel (coke) for 6 or 7 tons of ore. The reduced copper
is run into pigs or ingots of 250 to 300 pounds (115 to 160
kilogs., nearly) weight, and containing 2 or 2.5 per cent. slag.
Sulphuretted ores are smelted both in reverberatory fur-
naces and in cupolas. By the first method, the ores and
slags, containing a mean of about 33 per cent, copper, are
treated in charges of 4 tons each, and about four charges are
worked in 24 hours. The matte is roasted and fused until a
regulus is obtained containing 70 per cent, copper. This is
slowly melted, the sulphur oxidized out of it, the slag
skimmed and the charge oxidized sufficiently by the air-
REDUCTION OF COPPER ORES. 53
e
blast to form oxide of copper and sulphurous acid and to
produce the reactions,
2 CuO + CuS = 3Cu + SO2
SO;;.
The gases thus carry some sulphuric acid. The metal
should finally contain over 95, and even 98, per cent, copper.
With labor at $2.25 and $1.50 per day and coal at $4.00 per
ton, the cost of reduction is about $35 per ton of copper pro-
duced.
Cupolas and modifications of the broad-mouthed furnace
of Rachette are also used for smelting the sulphuretted ores,
and the cost is thus often reduced some 30 per cent. These
furnaces are not as well adapted to treating a wide variety of
ore as the reverberatory.* The latter is much better fitted
than the former for smelting arsenical ores, and for use
where wood is cheap, and charcoal, coal or coke expensive.
The slag from the cupola is cleaner, the cost of repair may be
made less, and no temporary loss of copper occurs as by its
permeation of the bed of the reverberatory.
When the ore is very lean, or contains elements difficult
of removal by smelting, or when the separation of silver or
other valuable metals alloying with copper is necessary, wet
methods of reduction are practised. The copper is either
separated by solution or by separate precipitation. Such
processes are adopted to save the metal otherwise lost in
mine waters either below ground or flowing from ore-heaps.
Copper reduced by the dry method is liable to consider-
able injury by absorption of oxygen while in fusion. The
extent of this injury is well shown by the behavior of bars
made for test by the author f in the course of investigations
of the properties of bronze alloys.
An analysis was made of the turnings of these bars for
the purpose of learning whether the chemical composition
would account for the presence of blow-holes and the lack of
ductility.
* " Mineral Resources of the United States." J. Douglas, Jr., p. 270,
f Report of U. S. Board, vol. i. ; 1878.
54 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The result was the discovery of an extraordinary amount of
suboxide of copper in bar No. I. This was no doubt caused
by repeated meltings.
The following are the analyses:
NO. I.
Per cent.
NO. 30.
Per cent.
Metallic iron
o 020
o 014.
Metallic zinc
O Old.
O O^7
Metallic silver . .
OO^c
Metallic arsenic
none
Metallic antimony
Metallic tin
none
Metallic bismuth
none
none
Metallic lead
trace
Metallic copper
87 ooo
06 T3O
Suboxide of copper
12.086
-i cgn
Carbon
none
100.055
99-995
No. 30 had been less exposed to the air than No. I and
less frequently remelted.
34. Metallic Copper, although both malleable and duc-
tile, excels in the first quality and finds more frequent em-
ployment in the form of sheet metal than in that of wire.
These qualities are possessed in the highest degree by the
pure metal and are greatly impaired by very slight admixture
of foreign elements of metallic alloy. Its tenacity and hard-
ness, although less than that of iron or steel, is greater than
that of any other non-ferrous material ; and its power of
resisting oxidation, of taking a fine polish and of easy work-
ing, make it an extremely valuable material to the engineer.
Good copper should have a strength of at least 30,000
pounds per square inch (2,109 kg- per sq. cm.) ; and cold-work-
ing, by wire-drawing, for example, raises its tenacity some-
times to double that amount. If worked hot in the presence
of oxygen, it is liable to serious injury by internal oxidation,
and, in presence of carbon, by the formation of the carbide.
It becomes hard and brittle when hammered or wire-drawn,
COPPER OF COMMERCE. 55
and its ductility is restored by annealing, by sudden cooling — •
the opposite of the treatment required in annealing steel.
It can be forged, when pure, either hot or cold, more
easily than iron. It loses strength with increasing tempera-
ture. Its oxide and carbonate are poisonous, and its surface
is therefore tinned when it is used for culinary purposes or
where liable to serious injury by corrosion.
Copper is very seldom cast, unalloyed, in consequence of
the difficulty of obtaining sound, strong castings. When
fluxed with phosphorus, it is, however, possible to make
castings of good quality ; and silicon, also, is one of the best
known fluxes for all its alloys. " Phosphorus-copper " has a
strength, according to Abel, of from 30,000 to 50,000 pounds
per square inch (2,103 to 3>5X5 kgs. per sq. cm.), as the per-
centage of phosphorus added rises from one to three or
four per cent. Arsenic, in small doses, hardens copper.
Riche* found that the density of copper, subjected alter-
nately to mechanical action, then to tempering or annealing,
displays inverse variations according as it is exposed to the
air or sheltered from it during the re-heating ; while in the
first case the mechanical action increases the density, in the
second, mechanical action diminishes it.
Professor Farmer has informed the author that he has
succeeded in depositing copper, from cyanide solutions by
electrolytic processes, harder than untempered steel.
35. Copper of Commerce. — The copper found in the
market is of several kinds, each known commercially by a
different name.
" Lake Copper " is that obtained in the neighborhood of
Lake Superior, and is principally native copper. It is remark-
ably pure, and when well handled in melting and poling, it is
considered unexcelled for purposes as, for example, con-
ductors of electricity, in which every trace of foreign matter
reduces appreciably, and often seriously, the value of the
copper. The best Lake copper has ninety-three per cent, of
the conductivity of chemically pure copper.
Australian, South American, and European coppers are
* Comptes Rendus, vol. 55, 1862 ; pp. 143-7
5 6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
usually not native coppers, nor are the coppers obtained
from nearly every other part of the world. Japanese copper
is a richly colored metal, which comes into the market in
small ingots. All commercial coppers obtained from other
than deposits of native copper are likely to be contaminated
by the presence of arsenic, sulphur, oxygen, and metals.
Electrolytic copper is very pure and constitutes about half
the total production.
Copper, as sold in the market, contains from one-tenth to
one per cent, of foreign matter ; an excellent sample con-
tained 99.9 per cent, copper. One-tenth of one per cent, of
impurity, according to Egleston,* may reduce the conduc-
tivity of the metal ten per cent. The presence of one-half
per cent, may make the metal worthless for many purposes.
The following are analyses of three samples : f
AMERICAN COPPER. — EGLESTON.
ORE KNOB.
L. SUPERIOR.
BALTIMORE.
Metallic copper ........ .. .
QQ.SO
00.8*3
QQ.6«;
O.3Q
0.15
O.OO
o.oo
O.OO
O.OO
Silver
0.05
O.O26
0.066
Lead
O.OI
O-OI6
O.O44
O.OO
0.00
0.088
O.OO
O.OO
0.0^5
Silver in 2,000 pounds
100.25
14.6
100.02
7.O3
99.893
10.75
A sample of Swiss copper, found by Berthier J to possess
extraordinary softness, ductility, and malleability, was corn-
posed of
Copper 99-12
Potassium o. 38
Calcium 0.33
Iron 0.17
and that author concludes that its valuable properties are
* Trans. Inst. Min. Engineers, vol. x., p. 63.
f Ibid., p. 54.
\ " Essais par la Voie Seche."
COPPER OF COMMERCE. 57
due to the presence of the alkaline metals. Mallet proposes*
to introduce an alloy of sodium and tin in the manufacture
of gun-bronze to secure freedom from oxide, using 0.05 per
cent, sodium, or less.
Copper is too soft, and usually too weak, to be of as great
value in the arts as iron, even were its price to admit of such
use. It is principally employed in the form of sheets and
wire. Copper in heavy sheets is sometimes used for the
" fire-boxes " of locomotives, where iron would be rapidly
corroded ; it is extensively used in making large vessels for
manufacturers of chemicals and pipes. Copper pipes of
large size, such as are used on marine engines for steam and
feed pipes, are made by rolling up sheet copper and brazing
the edges together. Small pipe is sometimes drawn to size
in dies ; feed and " blow-off " pipes are usually thus made ;
this " solid-drawn " pipe is more costly, but much better, than
brazed pipe."
The ductility, malleability, and the considerable strength
of copper, permitting its being worked into rods, bars, wire,
or sheets with equal facility, make it, next to iron, the most
useful of the metals. Its quality is so greatly dependent
upon its purity and freedom from oxidation or admixture
with other metals, that it is very important to the engineer
to see proper precaution observed in obtaining it for struct-
ural purposes.
Working by the hammer, in the rolls, or in the wire-mill,
causes great increase in tenacity, while carelessness in melt-
ing and casting it may render it worthless for the purposes
of the engineer, and even the strengthening processes cannot
be carried far except with occasional annealing. It may be
worked either cold or hot, and forged like iron, if not so
highly or so long heated as to cause serious oxidation. It
oxidizes quickly at high temperatures, and also when exposed
to a damp atmosphere. Fusing it under a layer of salt, it is
less liable to injury in the foundry.
Thin sheet copper is subject to a peculiar deterioration
of strength, with time, which has been studied but little, and
* " Construction of Artillery," p. 97.
58 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
the cause of which is not fully ascertained. This degrada-
tion of quality is singularly irregular and erratic, and affects
the product of the best mills, as well as low grade copper.
It has been noticed particularly in thin metal, as cartridge
sheets. This metal is sometimes of nearly pure copper, but
often of alloy with zinc in considerable amount. Cartridge
metal, passing the severest tests, was reported by Capt.
Michaelis as failing in firing ; later an improvement was
observed. Dr. Egleston attributed failure in such cases to
several causes, as impurities in the copper, oxidation, over-
heating, underheating, and over-compression in the rolling
mill. Large quantities of gas are sometimes separated from
the metal, often many times its own bulk. The stress and
flow caused by the presence of this gas may be the most
usual cause of loss of strength with time.
Copper is rarely worked in the lathe or by cutting tools ; it
is soft, yet tough and tenacious, and is easily distorted by the
resistance offered to the tool, which it clogs and causes, espe-
cially if the latter is sharp and has an acute cutting angle, to
chatter and dig into the work. Its peculiar qualities fit it well
for working with the hammer, and it is often forged hot, and
still oftener worked cold. Pieces are often cast and then
hammered into the desired form, or beaten to the required
degree of thinness. If, during the process, the metal becomes
too hard and brittle, it is annealed by heating and suddenly
cooling it.
Joints are made by soldering or brazing, or by riveting.
Welding is practicable with a flux of one part sodium phos-
phide, two of boracic acid.
Copper vessels are usually brazed, and when used for
culinary purposes, or when liable to be filled with alkalies or
other substances which may dissolve the metal, are tinned.
This operation consists in first thoroughly cleaning and
brightening the surface by scraping or sand-papering, then
washing with a solution of sal-ammoniac, or of zinc in hydro-
chloric acid, which leaves a clean metallic surface, free from
oxide and greasy matter. Tin is then melted in the vessel
and rubbed over the whole interior, the surplus finally poured
SHEET COPPER.
59
off, and the polishing completed. Oily and ammoniacal
matters, and according to Sir Humphrey Davy, weak solu-
tions of salt, attack copper, as do nearly all acids.
36. Sheet Copper was formerly much used by engravers,
but has been much less generally called for by that trade
since other engraving processes have been perfected. En-
graved rolls for calico-printing often have their surfaces made
of the finest sheet copper, but are sometimes made of the
cast metal. Embossing cylinders are made of copper or gun-
metal. The patterns are produced either by engraving or by
stamping.
Sheet copper is used to some extent, but less than for-
merly, in lining air-pump cylinders for steam engines and
pumps used in mines, where the water is found to seriously
corrode iron ; but here, as in sheathing ships, alloys with tin
or zinc have displaced the unalloyed metal.
The sheet copper found in the market is classed as Bra-
zier's Sheets and Sheathing Copper. The sizes of the sheets
are :
SIZES AND WEIGHTS OF SHEET COPPER.
BREADTH.
LENGTH.
WEIGHT.
Brazier's
2 feet.
4 feet.
5 to 25 Ibs. per sheet.
2i "
3 "
4. "
14 inches.
5 ;;
6 ."
48 inches.
9 to 150 " "
16 to 300 " "
16 to 300 " "
14 to 34 oz. per sq. ft.
The weight may be approximately computed by multiply-
ing the cubic contents of the mass in inches by 0.3212 to
obtain the weight in pounds.
The thickness of sheet copper is often measured by wire-
gauge, and the diameter of copper wire is always so meas-
ured.
Copper is used to some extent in electro-plating, and is
of common use with a slight alloy of hardening metal in
coinage ; sheet copper is often tinned. Nearly all the copper
60 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
used in the arts, however, is alloyed with zinc and tin to form
the brasses and bronzes.
When used unalloyed, specifications should call for a
tenacity of at least 2 5,000 pounds per square inch in castings,
35,000 in bars, and 60,000 in wire (5,075, 7,105, and 4,218
kgs. per sq. cm.).
Copper wire is used in enormous quantities in the con-
struction of electric and magnetic apparatus. Its great
conductivity, which is six times that of iron, makes it pecu-
liarly valuable for this purpose. Its greater conductivity for
heat, also excelling iron two and a half times, has given it
value for heating surfaces of steam boilers. Copper " fire-
boxes " are often used in locomotives, and copper utensils
are of frequent use in minor departments of engineering, as
in distillation, and in chemical and culinary operations. It
is used to some extent in the sheathing of wooden vessels ;
but one of its alloys, a special sheathing metal, has now
nearly taken its place. The " fastenings " of wooden ships
are, in the best practice, always made of copper; it oxidizes
very slowly, and its oxide does not injure the timber through
which it is driven. Its use unalloyed is far less extensive,
however, than when alloyed with other metals.
The steam and feed-water, and other pipes used on ship-
board and on locomotives, are often made of copper, as are
the staybolts of heating surfaces when the latter are made of
this metal. Sheet copper is rolled, for fire-boxes and other
purposes, up to 10 feet 10 inches (3.3 metres) long. These
sheets must be free from cracks, blow-holes, or scale ; and to
secure a good surface, the sheets are inspected while going
though the rolling mill, and any defects detected are carefully
removed by the chisel, or by scraping, before the finishing
pass is given. It is even necessary, frequently, to plane the
ingots before rolling them.
Fire-box tube-sheets are hammer-hardened, in order that
the " expander " used in setting the tubes may not distort
the sheet. Hammer-hardened copper, when tested by ten-
sion, stretches irregularly, and the hammer-hardened plate may
thus be distinguished from plate not so treated ; the effect is
COMMERCIAL COPPER. 6 1
also seen in the diminished elongation without much change
of tenacity. Moderate hammering, according to Lebasteur,
is quite as effective as more severe work.
Copper rods, or bars, are made with the same care, and
the same precautions are adopted, as in making sheet copper.
If reduced by the wire-drawing process, the reduction must
be small at each pass, and the metal should be occasionally
annealed, if the reduction is considerable. The maximum
reduction in diameter should not exceed ^th inch (0.16 centi-
metre). Rods intended for fire-box stays are often drilled
through the axis of the stay, as a means of detecting fracture ;
these stays are now sometimes made by rolling up heavy
sheet copper on a mandril and then drawing to size.
Copper tubes and pipe are sometimes made by repeatedly
stamping disk-shaped ingots under the hydraulic press, and
thus gradually changing their form to that desired. Very
large quantities of copper are used in coinage.
The consumption of copper in the United States is not
far from 40,000 tons per annum, and a very nearly equal
amount is used in Great Britain (2.8 Ibs. per capita).
Copper is, when cast, rendered sound and strong by th^
use of phosphorus as a flux. Abel, in 1860, found that
the introduction of 2 to 4 per cent.* produces a remarkably
uniform, sound, dense and tough metal, exceeding the
strength of ordinary gun bronze by one-half, and attaining a
tenacity of 50,000 pounds per square inch (4,218 kilogs. per
sq. cm.)
Alloyed with tin to form bronze, and with zinc to make
brass, copper has extensive use in all the constructive arts.
It is used in alloying gold and silver for coinage, plate, and
other similar purposes for which those metals are too soft.
The copper usually amounts to about ten per cent, of the
total weight.
COPPER TELEGRAPH WIRE, as stated by Glover & Co., has
weight and conductivity, if pure, as follows :
* Construction of Artillery ; Inst. Civil Engineers. lS6o.
62 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Bf
n
l
n
«l
fi!
aj
H
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B
•tffgZ- x sp ii
•tpui
a-renbg
oo oo vo
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in\o
7 ft
VS;
N N ro
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5JS%a 5J>
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OO
t^
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64 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
37. Tin (St 'annum ; Sn.) is less widely and less plentifully
distributed than copper, but has probably been as long known
and as generally used. In fact, the two metals have always
been, as they are to-day, almost invariably used together ;
and their alloys, the bronzes, have been in general use since
the earliest times. The ores of tin are found and worked
extensively in Devonshire and Cornwall, Great Britain, and
less extensively in Malacca, Banca, Germany, and Australia,
in small quantities at Ashland, Alabama, and lately in the
Black Hills of Dakota. Banca tin usually commands the
highest price ; it is known in the market as " Straits Tin."
Tin is found as " stream tin " (cassiterite) in many parts
of the United States which are underlaid by the primitive
rocks, and the ores are found in small quantities in California
and other States west of the Mississippi, in Maine, and in
Alabama. It is only worked at Ashland, and in a few other
localities scattered over the United States. The tin used
in the United States comes principally, via Great Britain,
from Banca, Billiton, Cornwall, Australia, and South Amer-
ica. The amount is about 20,000 tons annually.
Tin sometimes occurs in the metallic state, but is gen-
erally found as an oxide.
38. Ores, and Processes of Reduction.— The common ore
of tin, cassiterite, stannite, stannic oxide, Sn O2, is a dioxide,
and is often called tin-stone or stream-tin. The ore usually
contains between 65 and 75 per cent, metal. It occurs in
veins traversing the primitive rocks. Much care is demanded
in dressing it, and in assorting it into the four qualities
usually classed at the mine. The ore is stamped, washed,
weathered a few days, calcined, again weathered and washed,
and finally smelted in reverberatory furnaces. The tin thus
obtained requires refining, which is done as in the working
of copper, the melting and poling demanding and occupying
five or six hours, and yielding a very pure metal. The blast-
furnace is sometimes used instead of the reverberatory, and
is said to yield a purer tin.
In detail, the processes of preparation are as follows :
The oxide comes to the metallurgist as " tin-stone," or
PRODUCTION OF TIN. 65
oxide, either as " stream tin ore," called often " alluvial ore,"
or " mine tin ore." The former is usually comparatively
clean. The latter is washed, to free it from the earthy mat-
ters accompanying it, by stirring it on a grating under a
flowing stream ; it is then assorted carefully, the stony and
useless part picked out and thrown away, the remainder
broken, if in large pieces, and reduced to a sufficiently small
size to work well under the stamps.
The stamps consist of a series of heavy blocks of wood
shod with cast iron, usually weighing 225 pounds (102 kilo-
grammes) or more, mounted on the lower ends of vertical
shafts. They are lifted by cams revolving on a horizontal
shaft, which engage lugs secured to the vertical rods. The
motive power is either water or steam, and the stamps make
fifteen to twenty-five blows per minute. The stamps fall
into a trough into which the ore is fed, and as it is pulverized
by the blows it is washed out at the side, through a finely
perforated screen, by a constantly flowing stream of water.
From the stamps, the fine ore is carried by the current to
a succession of settling tanks, in which it collects, while all
other and lighter matter is swept away. The " slimes " thus
retained are removed, are again washed in a flowing stream
of water, and are then sent to the calcining furnaces. These
are reverberatory furnaces, in which the sulphur and arsenic
are driven out of the pyrites with which the ore is usually
contaminated. The addition of common salt aids in this
process, by the production of vaporous chlorides.
The ore is now washed once more to remove the sulphate
of copper which exists in the mass, and often still again to
free it from oxide of iron and other lighter mineral matters,
leaving the " black tin " in proper shape for smelting.
The smelting process is conducted in reverberatory fur-
naces similar in general form and method of working to those
used in iron working. The charge of ore, now containing
about sixty per cent, tin, and weighing a ton or more, includ-
ing about twenty per cent, its weight of ground coal and
lime, introduced as a flux to remove the silica, is dampened
with a small quantity of water and spread upon the hearth.
5
66 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
At a low, and long-continued heat, the 'oxide of tin gradually
becomes deoxidized by the carbon present, and the metallic
tin settles in the middle of the furnace, the hearth being
slightly dished to receive and retain it. The ore is contin-
ually stirred as this goes on, to facilitate the settling of the
tin ; while the heat is finally considerably raised to produce
a fluid slag. The slag is finally removed, and the tin is run
off into a reservoir, from which, after the dross has risen to its
surface and been skimmed off, the metal is cast in ingots. A
portion of the slag is sufficiently rich in tin to be re-worked.
The ingots of tin, made as above, are refined by re-melting
and separation from the dross, and then " boiling" in a large
refining basin, kept at a moderate temperature, somewhat
above that of fusion, by a process resembling in principle the
" poling" of copper. The wood is secured in the bottom of
the tank under the tin, and the steam and gases rising from
it as it chars beneath the molten tin, cause the foreign
materials to separate and rise to the surface.
This process being completed, "the tin is again cast in
ingots ; the quality of the metal being determined, not only
by the extent to which the purification has been carried, but
on the part of the pool from which the ingot is cast. The
upper part is purer than the lower, and yields " refined tin,"
while the lower portion is ordinary " block tin " ; they should
contain from 0.985 to 0.998 pure tin. The lowest part of the
molten mass in the basin is reserved for further refining.
A small blast-furnace is sometimes used, as in Saxony, in
reducing the ore ; but it is a wasteful process. The fuel is
charcoal, and the flux is either siliceous or calcareous, accord-
ing as the ore contains an excess of basic or acid constit-
uents.
39. Commercial tin is never pure. Chemically pure tin
has a specific gravity of 7.28 to 7.4, according to the method
of preparation, the purest being lightest. Its atomic weight
is 116; color white, with a tinge of yellow; it possesses a
peculiar odor; it oxidizes with difficulty, and when bent
emits the crackling sound known as the " cry of tin." It has
little tenacity, considerable ductility, and greater malleability.
COMMERCIAL TIN.
67
The coefficient of expansion is 0.000023 ; its melting point is
443° Fahr. (232° Cent.) ; specific heat, 0.0562 ; latent heat of
fusion, 14.25. It boils at a white heat ; its conductivity is low.
Tin oxidizes very slowly in the air at ordinary tempera-
tures, but burns quite freely at a white heat and with a white
flame. Exposed to severe cold it becomes crystalline and
friable. Its principal uses are in the making of alloys with
copper, zinc, lead, etc., and in the manufacture of " tin-plate."
The yellow oxide is used for polishing metals, such as
steel cutlery and glass. The white oxide is used in making
a white opaque glass generally known as " enamel."
This metal is readily rolled into very thin sheets, known
as tin-foil, and drawn into tubes and into fine wire. It
resembles zinc in its change from great ductility at the boil-
ing point of water, to equal brittleness at about 400° F.
(204° C.). It then melts a few degrees above the latter tem-
perature, as already stated.
The following is a complete analysis, made at the request
of the Author, of Queensland tin :
ANALYSIS OF " QUEENSLAND TIN.
Per cent.
Lead 0.165
Iron 0.035
Manganese 0.006
Arsenic trace.
Copper none.
Zinc.. "
Per cent.
Antimony none.
Bismuth "
Nickel "
Cobalt "
Tungsten "
Molybdenum "
Kerl * gives a set of analyses, thus :
KIND.
BANCA.
BRITISH.
PERUVIAN.
SAXON.
BOHEMIAN.
Elements. . . .
Tin
I
99.961
0.019
0.014
0.006
2
99.9
0.2
I
99.96
2
98.64
I
93-50
0.07
2.76
2
95.66
0.07
1-93
99-9
I
99-59
2
98.18
Iron
Lead
Copper
Antimony
0.24
O.2O
0.16
0.406
1. 60
3.76
2-34
O.I
* Metalhuttenkunde, 1873.
68 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Grain tin is made by heating ingots to a temperature at
which they become brittle and breaking them up by dropping
them on the floor.
Manufactured tin is found in the market in nearly every
form in which iron and copper are sold.
Tin-foil is made by rolling into plates and sheets, then
heating, doubling, and again rolling, and repeating the latter
processes until it is sufficiently thin for use as desired. It is
sometimes rolled down in a compound sheet composed partly
of lead ; and it is often alloyed with lead to make thin sheets
and other forms. Tin-plate is made, as described in the
preceding volume, by tinning sheet-iron, and consists prin-
cipally of the latter metal. Copper, lead, and zinc are some-
times tinned. Brass pins are tinned by dipping in a solution
of the chloride or of the oxide ; the other metals are some-
times similarly tinned.
Unmanufactured tin comes into the market as " block
tin," as " grain " tin, and in small bars or " sticks." Block tin
is cast in ingots or blocks in moulds of marble ; grain tin is
made by heating these ingots until very brittle, and then
breaking them up on stone blocks ; it is sometimes granulated
by melting and pouring into water.
The production of tin has been enormously increased
during late years by the increased demand for tin-plate, which
is due* to the growth of the " canning industries " and the
roofing business. The consumption now exceeds a quarter
of a million tons per year.
Sheet tin, or tin-foil, is often no more than one-thousandth
of an inch (0.00254 cm.) in thickness. The foil is used for
wrapping tobacco and other materials which are to be pro-
tected from the action of the atmosphere. Thicker sheets
are used in " silvering" mirrors by amalgamation with mer-
cury, and for making amalgam and for other purposes con-
nected with the generation and use of electricity. Pure tin
is used in making some tin vessels, as dyers' kettles. Its
cleanliness and excellent qualities make it valuable for tin-
ning culinary utensils. The tubes are used sometimes alone,
and often as a lining for lead pipe, in the supply of water to
ZINC. 69
houses. The wire is very ductile and moderately tenacious,
and has the perfect inelasticity exhibited by tin in all its
forms.
Tin is very extensively used alloyed with lead, in pewter
and Britannia metal, and sometimes with a little copper as a
hardening or "temper."
The evidence lately discovered of the existence of an
extensive region, bearing tin, in Dakota, according to the
report of Professor Blake,* and of other deposits in Ala-
bama, lead to the expectation of a large future development
of this industry in the United States.
Of the whole product of the world, over 15,000 tons per
annum are used in Great Britain, probably nearly 20,000 in
the United States. Cornwall supplies above 10,000 tons per
annum, Banca is producing large quantities, and Australia is
rapidly approaching that district in its production. The use
of tin for " tin-plates " — sheet iron tinned on both sides — is a
very great proportion of the total. Good " tin-plate " is
plated with the best tin, while the cheaper, or " terne," plates
are plated with cheap alloy. Good tin-plate is distinguished
by the thickness, evenness, and brightness of the coating of
tin, the absence of dark spots produced by imperfections in
the coating and of roughness due to the incomplete covering
of the rough iron surface. " Pin-holes " in the coating often
indicate a low grade of iron in the plated sheet. The iron
should be good "charcoal iron," but is often "coke iron."
The cheaper grades are as suitable for many purposes as the
more expensive.
40. Zinc in the metallic state was not familiar to the
ancients, although they were accustomed to use its ores in
the manufacture of brass. The alloy was used in coins occa-
sionally ; the Greek and Roman coinage was, however, prin-
cipally bronze. Zinc was probably discovered, five hundred
years ago, by Albertus Magnus, and by him called marchasita
aurea ; its modern name was first given by Paracelsus in the
middle of the sixteenth century. It became a regular article
of manufacture about 1720, in ^Germany, and in England
* Engineering and Mining Journal, 1883.
70 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
fifteen or twenty years later ; the ore generally reduced was
calamine, and the process was one of distillation. The
metal had already been smelted in the East Indies. It has
been regularly manufactured in the United States since about
1850, first at Bethlehem, N. J., and later in a number of other
localities. The city of St. Louis, alone, supplies the market
with fifteen tons per day. The whole product for the United
States was, in 1900, about 125,000 tons (or tonnes, nearly).
Zinc ores were known to the ancients, and were used in
the manufacture of brass long before the art of reducing
them was discovered. The alloy was made by smelting
together the ores of copper and zinc. The metal became
known about 1600, but was little noticed until after Hobson
and Sylvester discovered, in 1805, that it becomes ductile
and malleable at about 300° F. (144° C.), when it was brought
into the market in competition with lead. It has since been
extensively used for sheathings, roofing, culinary, and other
vessels, architectural ornaments, etc. The oxide is exten-
sively used as a substitute for white lead.
41. Ores of Zinc occur abundantly in the United States,
the best being obtained in New Jersey, Pennsylvania, and
Virginia, and in a line of deposits running through West
Virginia and the Middle States, across to Illinois, Missouri,
and Kansas, and north into Wisconsin. Large quantities are
mined in Missouri and other parts of the country. They are
mined extensively in Europe. Calamine and blende are the
ores principally used in the production of the zinc of com-
merce.
These ores are the carbonate known as calamine, the sili-
cate, or siliceous calamine, the sulphide, or blende, and the
oxide, or red ore.
The latter is given its color by the oxides of manganese
and iron which are present with the zinc. It is the common
ore of New Jersey. Calamine is also found in the United
States, near the red ore. It is a common ore in the North of
England and in Scotland, in Belgium, Silesia, Spain, and
Sardinia. It is an impure carbonate, having a peculiar
columnar structure, a dirty red color, and moderate cohesion.
ORES OF ZINC. 71
It often contains lead, iron, manganese, and cadmium and
rarer metals.
When raised from the mine, the ores are carefully picked
over, and the gangue and lean ores removed as completely
as possible. They are next broken to small fragments or
powder under stamps, and washed very thoroughly.
They are calcined and smelted, the calcination rendering
them porous and more easily reducible by driving out moist-
ure and carbonic acid. The process is generally conducted
in reverberatory furnaces, but sometimes in kilns.
In smelting, the ore is mixed with half its weight of any
cheap form of carbon, the two materials being well ground
and mixed, and is reduced at a high temperature in retorts
or muffles, usually three feet long and eighteen inches high,
a half-dozen being heated in a single furnace. The reduced
metal passes off in the state of vapor, condenses as it issues
through a properly formed channel, and flows into the moulds
placed to receive it. The process is therefore one of distilla-
tion.
Two processes are in use — the Belgian and the Silesian.
In the former the distillation is carried on in cylindrical
retorts, four or five diameters in length, put up in " benches,"
which consist of forty or fifty, or even more, set in several
rows, one above another, within a furnace stack, with one
end depressed and accessible from the front. Two or four
furnaces are often built in one structure, and their products
of combustion are led to a single chimney. The upper rows
of retorts are charged with about sixteen pounds (7.26 kilo-
grammes), and the lower with fifty per cent, more ore, the
charge being first moistened to prevent the formation of dust.
The furnaces and retorts are heated separately, and after
three or four days* heating the former, the latter are intro-
duced. The open end of the retort is closed by a fire-clay
plug to which an iron funnel-shaped cap is fitted to conduct
the distilled zinc away, while acting also as a condenser.
Every two hours these are removed and cleared out, the zinc
collected in them thrown into a ladle, and the unreduced
oxide found with it is re-worked later. The retorts are re-
72 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
charged every twelve hours, and the furnaces are only stopped
for repairs about once in every two months. The zinc is
poured from the ladle, when filled, into ingot moulds.
In the Silesian process, the distillation is carried on in
ovens or muffles, which are better calculated to bear high
temperatures, and in which, therefore, the work can be more
perfectly done.
The distilled zinc runs down an iron tube, which is the
condenser, into a small reservoir at the mouth of the oven.
Thirty-two are set in a furnace. They are re-charged once a
day. Re-melting is carried on in clay-lined iron crucibles or
kettles. The fuel consumed in these processes is from about
six times the weight of ore in the best examples of Belgian
work, to twelve or fifteen in the Silesian furnaces.
Zinc ores are often found to contain lead, and their treat-
ment by usual processes is somewhat difficult. Thus Chen-
hall * gives :
COMPOSITION OF ZINC ORES.
CONST ANTINE.
CAVALO.
BLUESTONE.
AMERICAN.
Zinc
IO.64
I3.4O
2Q.28
27 2O
Lead
4.8l
17.14
I2.QO
12 OO
Copper
I . qc
O 44
0.65
O 2O
Silver and Gold
O.O4
O.O6
O.O3
Sulphur
26 8q
ic. n.-j
22. 14
Iron
10.07
4.08
7.16
Alumina
2.33
I. O2
Magnesia .
O.22
35.O4
Silica
26.48
II. IQ
26.84
0.65
0.13
O.I5
Lime .
o 60
0.84
Sulphuric Acid
•3. ca
Antimony
O.O2
Oxygen and loss
2 77
I.OI
I.OI
IOO.OO
IOO.OO
100.00
These ores are treated by the Parnell process of dissolving
in sulphuric acid, and decomposing the sulphate by heating
Proc. British Institute Civil Engineers ; 1882-3 ! Part iv.
METALLIC ZINC. 73
it with the sulphide. The loss is reported to be, for lead
ores, which are similarly treated, three per cent.
Commercial zinc thus prepared usually contains some
lead, and may contain a considerable amount. Where needed
pure, it should be very carefully selected by analysis.
42. Metallic Zinc is a bluish white metal known to the
trade as "spelter"
Its atomic weight is 65. It is rather brittle, and can be
rolled satisfactorily only when heated somewhat above the
boiling point of water. When pure, it can be worked, with
care, into bars or sheets at ordinary temperatures. After
passing the boiling-point, it again gradually loses its ductility
and malleability, and can be powdered readily at a tempera-
ture somewhat below the red heat.
The rolling of this metal was at first accomplished with
very great difficulty, from the fact that its malleability is
confined to very narrow limits of temperature. For this
reason it is always an operation only entrusted to experienced
hands. The most suitable temperature is about 120° Cent.
(248° Fahr.), and this must be maintained throughout the
process. Below this point the metal opposes too great a
resistance, and must be re-heated ; above this point it be-
comes brittle ; at 200° Cent. (390 Fahr.), it can be brayed in
a mortar.
Zinc should be re-melted before being rolled into sheets.
The heat of fusion varies between 400° Cent, and 500° Cent.
(750° Fahr. and 930° Fahr.). Re-melting is generally per-
formed in a reverberatory furnace to cleanse the zinc of im-
purities. The thickness of the ingots must vary with the
final dimensions required ; this renders re-melting indispens-
able.
The re-melted plates are first roughed down or rolled
between heavy rolls, and after being cut down to a fixed
weight, are taken to the finishing train, where the rolling is
completed. There are thus two distinct operations — the
roughing down and the finishing. Between the two, the
sheets are re-heated in annealing boxes placed upon the
melting furnace. Each operation gives rise to a production
74 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
of scrap, which is more or less large in amount according to
the quality of the metal and thickness of the sheet. This
scrap, and all defective sheets, are re-melted with the ingots
from the foundry.
The fact that zinc, heated to a temperature exceeding the
boiling point of water, becomes malleable, was discovered
about the year 1805, and rolled sheet zinc then soon made
its appearance in the market, and was used to some extent
as a roofing material.
Zinc is used extensively in the form of sheets for roofing;
sheathing of iron ships, domestic utensils, etc., etc. Very
large quantities are used by the engineer in the brass alloys
and in the surface-protection of sheet-iron. It unites readily
with the other useful metals to form alloys, which are usually
characteristically different from their constituents. The prin-
cipal of these alloys are the brasses, or alloys with copper.
The metal is also often mixed in small proportions with the
bronzes, or copper-tin alloys, to form the copper-tin-zinc ter-
nary alloys often used in machine construction. Of the
world's product of this metal, amounting to above 200,000
tons, the United States produces twenty per cent. Belgium
and Germany make two-thirds.
Zinc sheets of standard dimensions have the following
weights :
THICKNESS AND WEIGHT PER SQUARE FOOT.
Inch. Inch.
.0311 = 10 oz. -0534 = 14 oz.
.0457 = 12 oz. .0611 = 16 oz.
Inch.
.0686 = 18 oz.
.0761 = 20 oz.
Cast zinc, as well as rolled, is often used in the manufac-
ture of ornamental work ; it takes the impression of the
mould as sharply as good foundry iron, and is especially liked
for small work.
A prize offered in 1826 by the Society for Advancement
of Industry in Prussia, led to the discovery, by Krieger, of
Berlin, that hollow ware can be cast in zinc, and, by Geiss,
that it would make good architectural ornaments. An exten-
METALLIC ZINC. ?$
sive consumption of the metal for these purposes at once
arose, and the applications of zinc in these directions are
becoming rapidly more general. It is largely used in decora-
tion, as a substitute for bronze, and to a considerable extent
in the construction of large statuary ; in this case, however,
the mass is usually built up of smaller parts soldered together.
Berlin has been the head-quarters of this industry.
Zinc castings made at a high temperature are brittle and
crystalline ; when cast at near the melting point, they are
comparatively malleable. It is hardened by working, and
must be occasionally annealed.
The value for sheathing and for work exposed to the
weather, arises from the permanence and impenetrability of
the coating which forms over its surface — a basic carbonate.
Zinc is the most strongly electro-positive of the metals of
commerce, and is almost exclusively used as the perishable
element in voltaic batteries.
It has a specific gravity of 6.9 to 7.2, melts at 770° F.
(410° Cent.), and boils at 1900° F. (1040° Cent.) ; its vapor
burns readily with a bluish-white flame, forming the white
oxide.
The salts and the higher oxide of zinc are extensively
used in the arts, especially in making paints and dyes. The
chloride is used in large quantities as a preservative of timber
and as a disinfectant.
Rolled zinc is made very much as sheet lead or sheet
copper is made ; but its temperature must be kept at a little
above the boiling point of water, to secure the necessary
malleability, and it must also be free from alloy. It is freed
from its most usual constituent, lead, by re-melting the spel-
ter, as received from the furnace, on the hearth of a rever-
beratory furnace which has a gradual slope terminated by a
basin, into which the melted metal flows, and in which the
zinc and lead separate, the lead settling to the bottom, while
the zinc lies on the top. The zinc is ladled out and cast into
ingots for the mill.
These ingots are warmed to the proper temperature, and
then rolled into sheets, and sometimes into bars, between
76 MATERIAL? OF ENGINEERING— NON-FERROUS METALS
rolls kept heated by the passage through them of steam oi
moderate pressure.
Galvanized iron is sheet iron covered with a coating of
zinc by immersion in molten zinc.
Zinc is produced in the United States to the amount,
annually, of about 120,000 tons (1899), and the production
is rapidly increasing. At least one-half comes from Illin-
ois, one-third from Missouri, and nearly as much from
Kansas. New Jersey supplies zinc of excellent quality, and
furnishes all that is exported, sending abroad considerable ore.
The gas-furnace of Siemens is now adapted to smelting zinc,
and is coming into general use in consequence of its cheap-
ness of operation and manageability. The known deposits
of zinc are being rapidly worked out.
The importations of foreign zinc into the United States
are more than equalled by the export of special grades of
American zinc to Europe, where the metal is much sought
on account of its high value for the manufacture of military
rifle cartridge cases.
The amount of coal used for one pound of zinc is the fol-
lowing at the different works, the Eastern works using anthra-
cite principally, and the Western works using bituminous coal :
FUEL.
REDUCTION.
TOTAL.
4.5
1-3
5-8
5-5
1.9
7-4
4-5
1.7
6.2
4-4
1.2
5-6
The yield of zinc is stated to be
Lehigh, for calamine 73-5 percent.
Lehigh, for blende 70.0
Passaic, for calamine 80. o
Martindale, for blende and silicates 73 -O
Carondelet, for silicates 76. 80
Of the whole quantity consumed in the United States in
•n, about ten per cent, is used in galvanizing wire.
LEAD. 77
43. Lead (Plumbum ; Pb.) is a bluish-white, lustrous, in-
elastic metal, so soft that it may be easily scratched with the
finger-nail. It has too little tenacity to be readily drawn
into fine wire, although some lead wire is found in the market.
It is very malleable, and is very extensively used in the forms
of sheet-lead and lead-pipe. It is very heavy (S. G. 11,4),
and is easily fusible, melting at 620° F. (327° C.) ; it absorbs,
in fusing, 5.4 metric thermal units per kilogramme (9.8 B. T.
U.). Its specific heat is 0.03 at low temperature, and 0.04
near the melting point. The coefficient of expansion is given
by Calvert and Johnson at 0.00003. It is a very bad conduc-
tor of both heat and electricity. At high temperatures it
becomes slightly volatile ; in this respect and in changing in
character from ductile to brittle as the melting point is
approached, it resembles zinc somewhat.
Oxidation occurs but slowly in dry air, and the oxide
forms a protecting coating over the metal. When exposed
to moist air containing carbonic or acetic acid, however,
oxidation progresses rapidly. Lead is readily dissolved in
water containing carbonic acid or salts of nitric acid ; the
solution is poisonous, as all the salts of lead are cumulatively
poisonous.
Lead oxides are of great value in the arts. " Red lead,"
or minium (Pb4O5), is used, mixed with drying oils, as a pig-
ment, and by the engineer as a cement, in the latter case
often mixed with " white lead," a basic carbonate [2PbCO3Pb
(OH)2], which admixture gives greater hardening and cement-
ing power ; this quality is often still further improved by the
addition to the cement of red and white lead, in oil, in equal
parts, of several times its weight of borings of iron with a
little sal-ammoniac and sulphur. Red lead is much used in
the manufacture of flint glass.
Lead compounds are easily identified by the formation of
the yellow oxide in the reducing flame of the blow-pipe.
Lead salts in solution give a black precipitate when exposed
to the action of sulphuretted hydrogen.
Lead was known, but was of little importance in the
earliest historic times. It is supposed to have been discov-
?8 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
ered later than either copper or tin. It was the custom,
apparently, among the Hebrews and their contemporaries, to
engrave records of importance, and which were desired to be
made permanent, upon tablets of lead with an iron stylus.
The Phoenicians used the metal in weighting anchors, and
sold it to the Greeks and the Egyptians. It was used by the
Babylonians, according to Herodotus, in securing iron cramps
in masonry, probably in the same manner as is usual in
modern engineering.
44. The Ores of Lead are galena or the sulphide, and
the carbonate. Nearly all the lead of commerce is obtained
from galena, which consists of eighty-seven per cent, lead,
nearly, when pure, and 13 per cent, sulphur; it nearly always
contains silver, sometimes in quite large amounts, varying
from a fraction of one per cent, up to fifty per cent. ; arsenic,
copper, iron, and zinc. The ore is very often worked for its
silver. Galena is worked in Saxony and Bohemia, in Eng-
land, Spain, and the United States ; it is usually found in
the palaeozoic rocks. The ores worked in the United States
generally contain comparatively little silver, and are quite
pure. They are found principally in the valley of the Mis-
sissippi. Enormous deposits exist in Missouri, Iowa, Illinois,
and Wisconsin, in crevices and pockets in those lower Silu-
rian rocks which have lately been distinctively known as the
galena limestone. These deposits have been worked only
from about 1820, although the existence of the ores had been
then known more than a century. The ores of lead occur all
through the Alleghanian districts of the eastern United
States, but none are profitably worked.
Lead ores are now often smelted in furnaces of the
Rachette type, i.e., having a rectangular form and widening
section from bottom to top. These permit the use of a
low pressure of blast, and comparatively unlimited magnitude
of charge. The fuel is usually charcoal or coke, or both, the
flux is iron and limestone, or sometimes silica, and the ore is
broken to the size of the fist or of an egg. The ore is often
first roasted. The total fuel used amounts to from fifteen to
twenty-five per cent, of weight of charge.
THE SMELTING OF GALENA. 79
45. The Smelting of Galena is performed in a rever-
beratory furnace, first roasting it, usually adding a little lime,
until it is largely converted into lead sulphate. An increase
of temperature of furnace with an oxidizing flame drives off
the sulphur in the form of sulphurous acid, and the reduced
metal is tapped off. Some of the lead is volatilized, and is
condensed in the flues or in a vacuum chamber, constructed
for the purpose, in which it meets with a shower of water.
Antimony and tin, when present in objectionable propor-
tions, are oxidized by exposing the molten lead, in shallow
pans, to the action of the air. Silver is removed, often, by
the Pattinson process of concentration, by melting, agitation,
and slow cooling, with repeated separation of the crystalliz-
ing metal which contains little silver, from the more infusible
portion which is richer in the precious metal. The final
product is subjected to the action of the air at high tempera-
ture, which oxidizes the lead and leaves the silver in the
metallic state.
The lead-smelting process is very largely, like the process
of reducing copper, one of desulphurization. The prelimi-
nary roasting of galena converts a part into oxide of lead, the
metalloid passing off in sulphurous acid, while another por-
tion becomes a sulphate. The whole mass is then melted,
the sulphur all passing off in sulphurous acid, and the metallic
lead is left behind. This is done on the basin-shaped hearth
of a reverberatory furnace, which is about six feet (1.8 metres)
wide and 8 feet (2.44 metres) long, and is lined with slags
melted down in place. The .tap-hole for the slag is above
that for metal. The process of smelting is conducted in four
operations or " fires."
The lead tapped off at the first melting of argentiferous
ores is richest in silver. As soon as it is out of the furnace a
second charge is thrown in and roasted ; the dross from the
preceding charge is added.
Some lead is reduced and is tapped off after an hour or
more, and the remaining ore is, in the course of about twa
hours, converted into oxide and sulphate.
The temperature of the furnace has been, up to this
8O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
period, kept below the red heat, in order that the ore may
not melt down and the desired change thus be checked. The
heat is now increased to a full red, and the reaction of the
oxide and sulphates present upon the sulphide, leads to the
reduction of the lead, which runs off freely. This process
occupies about an hour, and the temperature of the furnace
has been alternately raised and depressed to facilitate the
separation of the metal ; a little lime being added, also, to
flux the ore.
The temperature is now again raised for another hour ;
more lime is added, and further reduction occurs. Finally,
the furnace is heated to its maximum temperature, and held
at this heat for three-quarters of an hour or more, when the
lead is tapped off, the slags hardened with lime, and reduc-
tion is complete. The whole process has occupied five hours
or more. The fuel consumed amounts to something more
than one-half the weight of the ore smelted.
The slag is still rich in lead, and is again worked separately.
The molten lead tapped off is often refined, as is done in
purifying tin, by the use of sticks of wood in the basin. It
contains a considerable amount, often, of silver, copper, anti-
mony, and iron, amounting sometimes to several per cent.
This is partly removed by the process of " softening," which
consists in running it into a reverberatory furnace, having for
its hearth a shallow basin, and there oxidizing out the im-
purities by exposing it to the oxygen-laden gases passing
over it. The process of smelting has of late been modified,
and is now very generally conducted in blast-furnaces, instead
of in reverberatory furnaces.
When rich in silver, Pattinson's process is adopted. This
consists in melting in a series of basins, in which the metals
gradually separate. Lead crystallizes at a lower temperature
than the alloy, and the molten metal being allowed to cool
slowly, crystals of comparatively pure lead are formed, which
are separated from the remaining mass which is richer in
silver, and are transferred from one melting pot in a series to
another; the lead richer in silver being gradually separated
until that to be sent to market contains little to pay for
COMMERCIAL LEAD. 8 1
further working. The melting pots are set side by side, and
the purer lead is transferred from pot to pot in one direction,
while that containing silver is similarly transferred in the
reverse direction, until the pots at the extremes of the series
contain, the one nearly pure and marketable lead, while the
other contains so much silver that it can profitably be worked
to recover it. This method is going out of use.
46. Commercial Lead. — The lead is run into "pigs"
about 3 feet (0.9 metre) long, usually weighing about 150
pounds (70 kilogs.). Spanish "pigs" weigh 1 12 pounds (50
kilogs.). A " fodder" is 8 pigs.
Pig-lead is rolled into sheets 6^ to 7^ feet (2 to 2% metres)
wide, 30 to 35 feet (9 to 1 1 metres) long, and sent to market
in rolls. The weight runs very nearly six pounds per square
foot for each o.i inch thickness (120 kilograms per square
metre per centimetre in thickness). Sheet-lead is extensively
used for tanks, sheathing, etc., and sometimes, although less
than formerly, for roofing. Lead-pipe is made as below by
forcing lead through an orifice, the size of the pipe to be made,
over a former which gives it the required internal diameter.
Lead shot is made by dropping the molten metal from
the top of a shot-tower of such height that the globules of
the leaden rain thus produced may cool and become solid
before striking the water in a tank at the bottom, placed
there to receive it.
Lead pipe is now made by a peculiar process called
"squirting"; it was formerly made by a process of " draw-
ing" through dies. In the modern process, the lead is
melted in crucible, or iron pots, and then carried to a com-
pressing chamber fitted with a plunger which is driven by
hydraulic pressure. The lead is allowed to solidify and cool to
about 400° F. (204° C.). The ram is then forced down upon
it, and, at a pressure of a ton and a half or more per square
inch, the lead flows freely from an orifice in the bottom of
the chamber, and around an iron core attached to the
plunger, thus taking the size desired, and issues in the form
of a pipe of a length determined by the relative capacity of
the chamber and section of pipe.
6
82 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Bar lead and lead wire and rods are made in the same
manner, but dispensing with the core on the plunger. The
compressing chamber is sometimes attached to the hydraulic
press plunger, and rises against a fixed plunger in which is the
orifice of issue, while the core is fixed in the compressing
chamber. This arrangement is more convenient and causes
less frictional resistance. Tin-lined pipe is often made.
The alloys of lead will be referred to later. The oxides
and salts have great value in the arts.
White lead, the carbonate of lead, is made by exposing
sheet-lead to carbonic acid and moisture. The lead is coiled
up in pots, piled in heaps and covered with spent tan-bark
and horse-dung. A little acetic acid, in each pot, attacks
the metal, forming the acetate, which is then altered into
carbonate by the carbonic acid generated in the hot-bed. It
it used extensively in making paints.
Red lead is produced by heating the protoxide in the
presence of oxygen and thus converting it into the peroxide.
Litharge is made by similarly acting upon the metallic
lead and thus forming the protoxide. It is used as flux, as
a constituent of cement and in the manufacture of red lead
and of glass.
The salts of lead are much used in medicine and to a con-
siderable extent in dyeing. They are all poisonous.
Lead is now produced in the United States at the rate
(1899) of about 220,000 tons annually, and the production is
increasing at the rate of ten per cent, or more a year. But
little is imported. Of that produced in the United States,
Utah yields about 20 per cent., Nevada, 6 to 8 per cent,
Colorado, over one-third, principally from Leadville, and
Missouri and Kansas 15 per cent.
Great Britain produces very nearly as much as the United
States, reducing Spanish and other imported ores, which are
principally argentiferous. Spain exported nearly as much
more, and Germany quite as much.
47. Antimony (Stibium; ££.), is a grayish white, crystal-
line and lustrous metal, moderately hard, extremely brittle,
of inferior tenacity and has a peculiar taste and odor. It
ANTIMONY ; BISMUTH. 83
melts at a low red heat, 840° F. (450° C), and may be dis-
tilled at a white heat in an atmosphere free from oxygen. It
does not oxidize in dry air at ordinary temperatures, but
takes up oxygen slowly in cool, moist air, and rapidly when
hot. It expands while solidifying, like iron. Its specific
gravity is 6.7.
The most common ore is the sulphuret, which is found
abundantly in Borneo and in considerable deposits in Eng-
land, France, and Hungary, and also in California. It is
reduced by roasting to expel the sulphur. The salts of
antimony are poisonous.
The metal is a bad conductor of heat and electricity, and
is used, with bismuth, is making thermo-electric piles. Its
principal use is in the manufacture of alloys, as britannia
metal, type metal, pewter, specula, etc. It expands when
solidifying from fusion. It is rarely used alone.
Antimony is found in abundance in the Rocky Mountain
section of North America, and especially in California and
Nevada. The ore is usually a crude sulphuret, containing,
often, some bismuth and a little silver. It is smelted at
several points and sold in the eastern markets for use in
making type metal, britannia ware, and babbitt metal.
Gray antimony was used by the ancients for coloring the
hair and eyebrows.
48. Bismuth (Bi. ; atomic weight, 208) is a brittle, pink-
ish white, heavy, useful metal, having some resemblance to
antimony. It has a specific gravity of 9.8 to 9.9. It expands
on solidifying, at a temperature of 500° F. (260° C.). Its co-
efficient of expansion is 0.00134; specific heat, 0.0305. It
crystallizes with remarkable facility. It may be distilled at
a high temperature. It is very diamagnetic. Its principal
use is in making alloys. It injures brass seriously.
The metal is obtained either by reducing the sulphide or,
oftener, by purifying native bismuth.
Its oxides and salts are used in medicine, and in the arts
to a moderate extent, only, almost invariably alloyed with
other metals.
Commercial bismuth contains many impurities, which are
84 MATERIALS OF ENGINEERINGS-NON-FERROUS METALS.
removed by fusion with nitre. Chemically pure bismuth is
obtained by precipitation, by dilution of its solution in nitric
acid. The bismuth of commerce comes principally from
Germany and Bohemia, and some from Peru. Deposits of
oxides and sulphides have been found in Utah.* The
quantity mined is not great and the demand is small, not
more than ten or fifteen tons being used in this country
annually. It has about one-eighth or one-tenth the value of
silver.
49. Nickel (Ni.; atomic weight, 58.8) is a bluish, nearly
silver white metal, having high lustre, considerable ductility
and malleability, and closely related, chemically, to iron and
cobalt, which metals are often associated with it, in nature.
It has about the hardness of iron, but is heavier, having a
specific gravity of 8.3 to 8.9, has about equal fusibility, but is
far less subject to oxidation and corrosion. Its oxide is
white and defaces the polished metal comparatively little,
and is easily removed. Nickel can be either cast or forged;
but it is generally used in making alloys or in plating more
oxidizable metals. It is magnetic, although much less so
than iron.
The Ores of Nickel are the arsenide, which is by far the
most common, and is known to the miners as kupfernickel,
the sulphide, the sulphate, and the silicate. Nickel ores are
found in France, Sweden, Cornwall, Spain, Germany, New
Caledonia, and in Oregon and other localities in the United
States, Canada now supplying the greatest quantity. The
ores are reduced by fluxing with chalk and fluor-spar, if
arseniated, or by roasting and then reducing with charcoal
and sulphur to the state of sulphide, and then by double
decomposition with carbonate of soda, obtaining the car-
bonate, which is finally reduced with charcoal. The metal
was discovered and the ore reduced as early as 1751 by Cron-
stadt. Large quantities come from New Caledonia.
The nickel ores of Oregon have the following composition
as given by Hood, as determined by analyses of ores sent to
San Francisco :
* Polytechnic Review, April, 1876.
NICKEL.
A.
B.
GARNIERITE.
NOUMEITE.
Silica
48.21
do ^
A<-l 2*1
Iron and alumina oxide. . . .
Nickel oxide
1.38
23 88
i-33
29 66
1.66
3.00
IQ OO
21 7O
Water
6.6-}
7.OO
521
12.51
12 73
^4. Amorphous. — Hardness, 2.5 ; specific gravity, 2.45 ;
color, pale apple green, becoming lighter by exposure. Ad-
heres to tongue ; not unctuous. Does not fall to pieces in
water.
B. Amorphous. — Hardness, 2.0-2.5 ; specific gravity, 2.20;
color, dark apple green, becoming lighter by exposure. Ad-
heres to tongue; unctuous. Falls to pieces in water.
Garnierite. Amorphous. — Hardness, 2.0-2.5 ; specific
gravity, 2.27; color, apple green. Adheres to tongue; not
unctuous. Falls to pieces in water.
Noumeite. Amorphous. — Hardness, 2.5 ; specific gravity,
2.58; color, dark apple green. Does not adhere to tongue;
unctuous. Does not fall to pieces in water.
According to Mr. Nursey, most of the nickel made in the
United States is produced by what is known as the Thomson
soda process. Matte of first fusion is freed from iron by sub-
sequent roasting and smelting. It is then smelted in a cupola
furnace with sodic sulphate and coke. The product of this
fusion when drawn off separates, whilst fluid, by gravity, into
two portions, a lighter and a heavier, which are separable
when cold. The lighter part, known as. "tops," contains
nearly all the soda, copper, and iron, whilst the heavier por-
tion, called " bottoms," contains nearly all the nickel. As
the separation of nickel and copper is not quite complete the
bottoms are treated over again, substantially in the way we
have described, until nickel sulphide of satisfactory purity is
obtained. Metallic copper is ultimately produced from the
tops, the very small quantity of cobalt present going with the
nickel and there remaining. The nickel sulphide when dead
roasted, becomes nickel oxide, which is considered to be suf-
ficiently good for use in the manufacture of nickel steel. To
86 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
produce shot nickel, nickel oxide is reduced, melted, and
poured into water. In this form the metal assumes a good
appearance, but it is not approved of for delicate uses. By
reducing, melting, and moulding the oxide, rough slabs are
formed, which, treated as anodes, yield electrolytic nickel of
high quality.
The French company, Le Nickel, melts the nickel silicate
of New Caledonia with gypsum, thus producing matte consist-
ing of nickel sulphide and iron sulphide. By successive roast-
ing and smelting, the iron is entirely removed as slag, and a
final dead roasting produces nickel oxide of the requisite
purity to yield, by reduction, good merchantable metallic
nickel. Some part of this nickel oxide is sold as oxide to
steel makers and others.
The Manhes converter is the invention of Mr. Peter
Manhes. Taking the matte just referred to, he concentrates
it by blowing air through it, when melted, in a basic lined
converter, thus removing all the iron. After clearing off the
slag he desulphurizes the metal by continued fusion in the
converter with lime and lime chloride. The pure nickel goes
to the bottom of the converter and is teemed into moulds for
the market.
50. Uses of Nickel. — Nickel plating by the electric cur-
rent was practised experimentally by Jacobi and Becquerel
in 1862, but it was commercially practised by Isaac Adams,
of Boston, some years later. The plating fluid is a solution
of the double chloride or the sulphate of nickel and ammo-
nium. The current is usually obtained from the magneto-
electric machine. This has become, during late years, a
very important industry, and nickel plating is adopted by all
manufacturers of small articles of metal subject to corrosion
and tarnishing.
The malleability of nickel allows of its being chased as
are silver and gold, and with the result of greater lustre,
while the qualities of brilliancy, hardness, and durability,
whether used solidly or in electro-plating, make it very
suitable for table service.
The sheet-nickel of commerce is as thin as o.oi inch
USES OF NICKEL. 8/
(0.025 cm.), and the wire is nearly as fine. It can be welded,
with care, and can be forged like iron.
Nickel coinage was commenced, about 1850, by Switzer-
land, and in the United States in 1857. This application,
and nickel plating by electrolytic action, absorb enormous
quantities. The working of this metal has been most exten-
sively carried on in the United States by Mr. J. Wharton, at
Camden, N. J., from sulphuretted ores mined at Lancaster
Gap, Penn. Sheets have been produced 6 feet (1.8 m.) long
and 2 feet (6.1 m.) wide.
Dr. Fleitmann's discovery, that a small dose of manganese
added to the molten charge, when ready to pour into the
moulds, renders the nickel sound, strong, malleable, and
ductile, has greatly cheapened, as well as improved, the prod-
uct. Fleitmann has welded together iron and nickel, and
steel and nickel. Nickel-steel, Fe. 75, Ni. 25, is non-corrodible.
Nickel is principally used in the arts in the manufacture
of hollow ware which is to be plated with silver, as practised
by Gorham, and for vessels of nickeled iron ; the latter are less
liable to injury than when the nickel is deposited by electrol-
ysis. It has come to be extensively employed in alloy with
steel for armor-plate, giving enormous shock-resisting power.
Commercial nickel often contains iron. Canadian (Quebec)
ores contained,* in the garnet, calcite, 50.40; chromite, 6.87;
chrome garnet, 49.73, and in pyroxene, silicon and alumina,
50.60 ; iron oxide, 8.73 ; magnesium and calcium oxides,
35.90; water, 5.83. The reduced ore gave: iron, 71.84;
nickel, 22.70. The slag contained no nickel.
Commercial nickel contains, usually, measurable amounts
of carbon, silicon, iron and often cobalt.
The nickel plates now largely used as anodes for nickel
plating are prepared by fusing commercial nickel, generally
with addition of charcoal, and casting in suitable form. The
subjoined analyses by Mr. W. E. Gard,f of such plates, show
that silica may be reduced and retained as silicon, and that a
considerable amount of carbon may be present :
* " Nickel Ores " ; W. E. Eustis. Trans. Am. Inst. Min., Eng.
f Am. Journal of Science and Art, 1878.
88 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
NO
I.
NO.
II.
NO.
III.
a.
b.
a.
b.
a.
b.
• 530
• "54Q
1 . 104
i 080
I QOO
I 830
.303
• 294
. I^O
. 125
,2<C
.268
Iron ...............
.464
.463
108
I TO
•3OI
118
Cobalt - .
.446
.4-38
trace
trace
Sulphur . . . .
040
• CK7
266
^4O
jo/1
006
[Nickel]
98 . 208
O.8.IQ.O
08 ^Q2
08. 'id.z
Q*7 44O
0-7 488
Total
IOO.OOO
IOO OOO
IOO.OOO
IOO OOO
IOO OOO
jOO OOO
No. I. was American nickel, manufactured and cast by
Jos. Wharton, at Camden, N. J. A careful examination by
means of Marsh's apparatus showed not the least trace of
arsenic or antimony. No. II. was a sample taken from a
cast nickel anode used by a nickel-plating establishment in
New Haven, No. III. a sample taken from the same anode
after it had been used in the plating bath until upward of
half its weight had been removed. Solvent action had ex-
tended quite through the plate, leaving as usual a porous
flexible mass retaining its original form. A comparison of
Nos. II. and III. shows that under galvanic action the car-
bon, silicon, and iron of the anode dissolved relatively slower
than nickel, while the reverse happens with sulphur.
51. Aluminum ; or, Aluminium (Al.; atomic weight, 27.5),
is a white silver-like metal, very malleable and ductile, a good
conductor of both heat and electricity, uniting with oxygen
only with great difficulty, and therefore little liable to cor-
rosion either by exposure to air or to the action of the
oxygen acids. It dissolves freely in hydrochloric acid and in
solutions of the alkalis. It is remarkable for its lightness ;
its specific gravity being 2.6 to 2.7. The salts of this metal
are not expensive, and are used in large quantities in the
arts ; the sulphate, alum, is the most useful, and finds its
most important applications in dyeing and calico printing.
The alloys of aluminium are very valuable. Its remarkable
lightness, combined with its strength, make it useful for
ALUMINUM; OR, ALUMINIUM. gg
alloys. Equal volumes have equal strength when steel IVT;
about 80,000 pounds tenacity. Specific heat (Richards), 0.227.
This metal was discovered by Wohler, in the year 1827, and
by him obtained in considerable quantity, twenty years later,
by reduction with sodium. Devilie obtained it in ingots on
a commercial scale, and the metal rapidly became familiar to
chemists. Rose, in 1855, found that it could be obtained
from cryolite, in which it exists as a fluoride, by reduction
with sodium.
Aluminium is made by Hall's process of solution of alu-
mina (bauxite) in a bath of molten cryolite (a double fluoride
of sodium and aluminium) and of electrolysis by a heavy cur-
rent of low voltage (2.8 to 4). This remarkable and impor-
tant invention transferred the metal from the class of rare to
that of useful metals and reduced its cost to less than copper
and brass, bulk for bulk. [See Appendix.]
Next to silica, the oxide of aluminium (alumina) forms, in
combination, the most abundant constituent of the crust of
the earth, in the form of hydrated silicate of alumina, clay.
Common alum is sulphate of alumina combined with another
sulphate, as potash, soda, etc. It is much used as a mordant
in dyeing and calico printing, also in tanning.
Aluminium is of great value in mechanical dentistry, as,
in addition to its lightness and strength, it is not affected by
the presence of sulphur in the food. Dr. Fowler obtained
patents for its combination with vulcanite as applied to
dentistry and other uses. It resists sulphur in the process
of vulcanization so perfectly as to make it an efficient and
economical substitute for platinum or gold.
The metal, aluminium, is distinguished from other white
metals by its peculiar gray-white color, differing from both
zinc and tin, and especially its remarkably low density, pos-
sessing as it does, but one-third the weight of copper, one-
fourth that of silver, and one-eighth that of gold. It has a
pleasant metallic ring when struck, and confers a beautiful
tone when introduced into bell-metal. Devilie made a bell
of but 44 pounds (20 kilogs.) weight, which was, however,
one and a half feet in diameter (^ metre), and exhibited an
QO MATERIALS OF ENGINEERING— NON-FERROUS METALS,
exquisite timbre ; it was presented to the Royal Society
in 1868.
It is sufficiently malleable and ductile to permit its being
rolled into thin sheets and drawn into fine wire. Its melting
point is at, or near, 1,300° F. (700° C. nearly), between the
fusing point of silver and zinc, and it does not evaporate at
any temperature yet observed. The metal may be worked
cold, like copper or soft brass, and may be coined perfectly
and easily. Oxidation occurs very slowly and it retains a
polish as well as silver. It has often been proposed for use
in coin, for which purpose it is well adapted by its beauty,
lightness, sonority, and non-oxidizing quality. Laboratory
weights have been made of the metal, and have remained
standard for many years- Its solubility in the solutions of the
alkalis is, as writh copper and silver, such as to prevent its use
for some purposes. It is very extensively used in making
fine articles of luxury, and is proposed for use for philo-
sophical and engineering apparatus, and for utensils. Some
3,000 tons per year are now (1899) so used. [See Appendix.]
Alloys of aluminium with other metals, with the excep-
tion of copper and zinc, are not in much use. There are
several manufactories of the metal producing considerable
quantities of product. Its cost is five per cent, of that of
silver ; that of the bronze is five per cent, of that of the metal
and somewhere about that of copper-tin bronze. See page 305.
52. Mercury (Hydrargyrum ; Hg.), often called quicksilver,
is used by the engineer for a number of important purposes.
It is a dense fluid metal, having an atomic weight, 200, a
specific gravity of 13.6, a specific heat of 0.032 to 0.0333 as it
passes from the solid to the liquid state, a coefficient of ex-
pansion, according to Regnault, of from 0.00018 to 0.000197
as its temperature rises from the freezing point of water,
o°, to 350 Cent. (32° to 662° F.) Its latent heat of fusion is
2.82 metric units per unit of weight (5.08 British). It boils
at about 350° C. (662° F.), forming a colorless, transparent,
poisonous vapor, and evaporates at all temperatures. The
density of its vapor, according to Dumas, is 6.976. It unites
freely, at ordinary temperatures, with several other metah
MERC 'UK Y 91
forming " amalgams." Iron and platinum are not among
these metals. Mercury is therefore preserved in iron bottles.
The Ores of Mercury are cinnabar, "vermilion," which
is the sulphide, and calomel, the chloride ; the former is
the usual source of the mercury of commerce. The metal
is sometimes found native, in small quantities ; it is fre-
quently alloyed slightly with silver. The ores of mercury
are principally mined in California ; but large quantities
are produced also in Spain, Austria, and China.
Mercury, or " Quicksilver," is only produced in the United
States, in California, where it is obtained from the red sul-
phide (cinnabar). The quantity produced is not far from
60,000 flasks of 76^ pounds each, per annum, and one-fourth as
much more is imported. Its principal use is in the manufac-
ture of vermilion (sulphide of mercury), and amalgamating
mirrors.
Cinnabar is dark brown in color, earthy in texture, and
very heavy, its specific gravity being 8.2 ; abrasion produces
a red powder and a red streak on the mass. The ore is
reduced by distillation and usually with considerable loss of
vapor. The ore is broken up into pieces somewhat larger
than an egg, and roasted in a deep furnace, of circular form,
closed at the top and connected by flues with a set of con-
densing chambers in which the mercury is condensed by
contact with iron plates, over which cooling streams of water
are kept flowing. The charges weigh 700 or 800 pounds
(318 to 363 kilogrammes), and are worked off in about three-
quarters of an hour; the fuel used per charge is 25 or 30
pounds (i 1.3 or 13.6 kilogs.) of charcoal. In some cases, as in
India, a reverberatory furnace is used in reducing the cinnabar,
when the ore is lean. In still other cases, lean ores are dis-
tilled in small iron retorts, holding about 70 Ibs. (32 kilogs.),
with lime, and the vapors are condensed in stone bottles half
filled with water, or, the retorts are larger and contain as
much ore as the furnace above described. Condensation is
effected in a " hydraulic main," kept cool by immersion in a
trough of water.
Mercury, as distilled, usually contains bismuth, lead, and
9- MATERIALS OF ENGINEERING— NON-FERROUS METALS*
zinc, and is often re-distilled in the iron bottles in which it is
purchased from the smelter, or purified by washing with
dilute nitric acid. A subsequent washing with water and
drying with filter-paper and then warming it, leaves it in
good condition. It is also purified by shaking with powdered
sugar or with charcoal, the impurities being thus oxidized out
by contact with air.
This metal is used in many lands of philosophical appa-
ratus, in the pressure gauges used for standardizing steam
gauges, in the barometer, in " silvering" mirrors, and in a
few alloys.
Mercury was the last metal discovered by the ancients,
and is supposed to have been known four or five centuries
before the Christian era. Red cinnabar, its sulphide, was,
however, used as a cosmetic several hundred years earlier,
and was imported into Greece and Italy, in enormous quanti-
ties, from the Spanish mines of Almaden. The Peruvians
made similar use of it at the time of the discovery of their
country by Pizarro.
53. Platinum (Pt.} is a metal possessing qualities of the
highest value in the arts ; but its considerable cost forbids
its common use. It is so named from the Spanish platiua,
the diminutive of plata, silver, because of its white, silvery
color. It is found in the mountainous portions of South
America, Central America, Mexico and California, in the
West Indies, and in the Ural Mountains, in the metallic state,
but mingled with ore of iron, copper, and the rarer metals,
and usually alloyed with a small quantity of iridium. Its
atomic weight is 197.4.
The metal is purified by solution in a mixture of nitric
and hydrochloric acids, precipitation by potassium chloride of
the double chloride of potassium and platinum, re-solution by
nitro-hydrochloric acid and reprecipitation by sal-ammoniac,
sometimes, after repeated solution, as the double chloride of
ammonium and platinum. The volatile element is driven off
by heating, and the " spongy platinum " remaining is welded
into a solid mass, after cleansing by trituratton and washing.
Commercial Platinum always contains osmium and usually
PLATINUM. 93
silicium and iridium. Fusion in the oxy-hydrogen flame
with proper fluxing removes these metals by oxidation and
the promotion of slag. Deville and Debray fuse the ore
with galena in a small reverberatory furnace, and, fluxing with
glass and litharge, obtain an alloy of lead and platinum nearly
free from other metals. This is expected to remove the lead,
and the platinum so obtained is refined on the lime-covered
hearth and thus obtained in a very pure state.
Various other ways are sometimes practised. The best
method of compacting the metal is by fusion, which can be
accomplished by the oxy-hydrogen flame in a little furnace
made by forming a cavity between blocks of lime.
Platinum is nearly as ductile as gold and silver, and is
only exceeded in malleability by those metals and copper.
It is white like silver and has nearly as high a lustre. It is
softer than silver and about as hard as copper; but it is
rapidly hardened by the addition of traces of iridium or of
rhodium. Its specific heat is 0.03243 at common tempera-
tures, according to Regnault. The coefficient of expansion
is 0.0000068 per degree, Cent., according to Calvert and
Johnson, 0.0000085 Per Bordaz, o.oooooi according to other
authorities, varying according to purity and physical condi-
tion. Platinum can only be fused by the oxy-hydrogen
flame or the voltaic arc. It is the heaviest of the metals
used in the arts, having a specific gravity of 21.15 to 21.5.
This metal is not oxidizable in the air or by any acid, although
a mixture of nitric and muriatic acids will slowly dissolve it.
At high temperatures, alkalis will produce corrosion by con-
tact with it, as will potassium sulphate, and sulphur,
phosphorus and arsenic. Chlorine attacks it slightly, iodine
and bromine not at all. Chloric acids dissolve it.
Platinum is principally used in the manufacture of vessels
required to resist heat or the action of acids, as crucibles,
evaporating basins, stills or retorts used in the concentration
of sulphuric acid, etc. Carbon and silica corrode it, and the
metals, generally, freely alloy with it ; its applications are
thus somewhat restricted.
Platinum was discovered by the Spaniards, in the sixteenth
94 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
century, in the gold mines worked at the time, on the
Isthmus of Darien ; it only became valuable in the arts two
centuries later, after Sickengen had, in 1772, found that it
could be welded at a single white heat ; it then came into
demand, its hardness, strength, freedom from liability to
oxidation, and especially its infusibility, giving it a value
nearly equal to that of gold.
54. Magnesium, (Mg.; atomic weight, 24) is a silver
white, lustrous metal, ductile and malleable, very light (s. g.,
1.75), readily combustible, easily cut and worked, and resem-
bling alumina in many respects. It melts and volatilizes
like zinc, and at about the same temperature. In the form of
powder or thin wire or ribbon, it takes fire like a shaving of
wood and burns rapidly, with an intense bluish white light
very rich in actinic rays.
It abounds in dolomitic limestone in the form of silicate
and carbonate of magnesia, in carnellite, a double chloride of
magnesium and potassium, from which it is reduced by
sodium, using fluor spar as a flux, purifying it by distillation.
Magnesium has been manufactured by two establish-
ments, the American Magnesium Company, Boston, United
States, and the Magnesium Metal Company, Manchester,
Great Britain. The English manufactory produced by far
the most. The former furnished large quantities for the
English army during the campaign in Abyssinia, the metal
being employed extensively for signals.
Magnesium can readily be ignited at the flame of a candle.
Combustion is frequently interrupted by the dropping off of
the burning portion, so that it becomes necessary to feed the
unburnt portion into the flame continually. The wire burns
to the best advantage if inclined at an angle of about 45°.
An uninterrupted and very brilliant combustion is produced
by lamps especially constructed for this purpose. Such a
lamp* is made by the American Magnesium Company. The
strips of magnesium are rolled up on cylinders in the upper
part of the apparatus. These strips are unrolled by clockwork
* From designs patented by R. H. Thurston, 1865. New Marine Signal
Light : Journal Franklin Institute, 1866.
ARSENIC. 95
in the lower part of the apparatus, and are carried between
two small rollers, the uniform motion of which feeds them
regularly into the lamp, where they are ignited. The ashes
are cut off at intervals by means of eccentric cutters, and
collect in the bottom of the apparatus. A small chimney is
added, which is very important, as producing a draught of
air directly through the flame. A portion of the products of
combustion is thus carried away, and the flame becomes very
intense, while it is less so without a draught. This lamp has
been found very efficient, especially for marine signals. At
trials made at sea, on two vessels stationed eight miles apart,
the signals could be readily distinguished ; it is said to be
visible 28 miles.
Larkin has constructed and patented a lamp in which the
magnesium is not employed as wire, or in strips, but as a
powder. By this means the clock-work, or other mechanical
device, has been dispensed with. The metallic powder is
contained in a reservoir, which has a small opening in the
bottom. The magnesium powder flows through this like the
sand in the sand-clock. It is intimately mixed with a certain
quantity of fine sand, in a manner diluted ; first, in order to
be able to make the opening sufficiently large ; furthermore,
to produce a continuous flow of the material. The mixture
falls into a metallic tube, through which illuminating gas is
led from the upper end. The mixture is ignited at the lower
end. The flame is very brilliant, and the remaining sand falls
into a vessel placed below, while the smoke passes away
through a chimney. A lamp of this character was adopted
in several forms of signal apparatus devised for the Army and
the Navy Signal Corps, by the Author, in the years 1866-70.
[See Appendix: Magnesium as Constructive Material]
55. Arsenic (As.; atomic weight, 75) is found native, but is
usually obtained from the sulphite or from the alloy with iron
known as arsenical iron. It is also found alloyed with other
metals. It is reduced from arsenical pyrites, or from arsenical
iron, by roasting in retorts, the arsenic passing off by subli-
mation and condensing outside as in the zinc manufacture.
The arsenic of commerce is made principally from German
96 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and Spanish ores. The oxide is easily reduced by heating
with carbon.
This metal is a gray, lustrous solid, of steely fracture and
color, having a density of 5.6 to 5.95, crystallizing in
rhombohedra, volatilizing at a red heat, with a garlic-like odor,
and oxidizing easily at a high temperature, but not readily at
a low temperature. It has no value in the arts of construc-
tion and engineering except in alloys.
56. Iridium (Jr.; atomic weight, 197) is the heaviest of
useful metals. It was discovered in the year 1803 by Tennant,
who analyzed the metallic residue which remains when
platinum ores are dissolved. Tennant proved that the platinum
residues contained two new metals, to one of which he gave the
name of iridium, on account of the varying color of its salts,
and to the other the name osmium, because of the peculiar
odor which its volatile oxide possesses. Iridium is found in
the platinum ores in considerable quantity in the form of the
alloys of platiniridium and osmiridium. The first of these
occurs in grains and small cubes with rounded edges ; the
second, usually, in flat, irregular grains, and sometimes in
hexagonal prisms. Iridium, in the cold state, resists the
action of acids and alkalies. It parts with its oxygen at a
high heat, and, although it possesses a number of valuable
qualities, has been used, until recently, only for the points of
gold pens. Its limited use was caused by the difficulty of
obtaining it in metallic form. It is found in Russia, Brazil,
California and several other countries, and is usually accom-
panied by gold or platinum. Since its discovery, numerous
chemists and metallurgists have unsuccessfully endeavored to
reduce the ore and obtain iridium in the metallic form.
Chemists have succeeded in producing some small pieces of
indium the size of a pea by means of the oxyhydrogen blow-
pipe flame, the metal obtained, however, being porous and
valueless. In 1855, George W. Sheppard, of Cincinnati, suc-
ceeded in producing a similar result with the aid of a power-
ful galvanic battery. Later, John Holland, of that city,
began experimenting in the same direction, and after several
years of trial succeeded in reducing the iridium ore to a solid
MANGANESE. 97
metal in common furnaces. He used phosphorus as a flux,
by means of which, it was said, the metal could be made to
fuse as easily as cast iron.
This new method of fusing iridosmine was discovered in
1881 ; it consists in heating the ore to whiteness and adding
phosphorus. The mass becomes at once fused, and the phos-
phide thus obtained is reduced by heating with lime. The
metal is exceedingly hard, has a brilliant metallic lustre and
is not attacked by acids; when pure, its density is 18.7.*
The ore used as above, and the metal, have been examined
by Clarke and Joslin.f The ore has a specific gravity of
19.182, the metal 13.77. The composition of the latter was
Iridium 80.82
Osmium 6.95
Phosphorus 7'°9
Ruthenium, Rhodium 7-2°
102.06
showing the fused metal to be a phosphide, of the formula,
Ir.P.
Phosphorus was found to re-act similarly with platinum.
57. Manganese (Mn. ; atomic weight, 55) is usually
found as a peroxide, although occurring in many other com-
pounds. Its oxide is reduced by carbon at a white heat,
usually by heating the peroxide in powder with oil. The
metal is also obtained by heating the chloride or fluoride with
sodium. It is gray in color, resembling light gray cast iron,
usually weak and brittle, heavy (s. g., 7 to 8) and slightly
magnetic. It is produced electrolytically like aluminium.
It has a strong affinity for oxygen, and it is this which
makes it valuable in the arts. In one of its forms it is quite
different, however. As reduced from the chloride by sodium
it is hard and does not easily oxidize.
Manganese is always used as an alloy. Its most usual
form is seen in " spiegeleisen" an alloy with iron used in the
* Proc. Ohio Mechanics' Institute, 1882.
\ Am. Chemical Journal, vol. v. No. 4, *883-
98 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Bessemer and other processes of steel-making, which is made
by direct reduction from manganiferous ores by the ordinary
small charcoal blast-furnace. It is cast either into pigs or
into flat plates. When very rich in manganese and compari-
tively low in carbon, it is called "ferro manganese." Spie-
geleisen contains from 3 or 4 to 8 or 10 per cent, manganese,
while ferro-manganese contains 20 to 80 per cent.
58. The Rare Metals are of no value to the engineer in
his everyday work ; they are enormously costly, and possess,
as a rule, none of the qualities which are essential to their
use in construction. They are here only referred to, to com-
plete the list.
Gold and silver are too well known to demand description.
They are both dense, but soft, metals, difficult of oxidation,
little subject to corrosion, and therefore sometimes very use-
ful in plating other metals not readily attacked by acids,
alloying with copper and some other metals readily, and
forming compounds which, like these metals themselves, are
of little or no value to the engineer.
Cadmium is a white, malleable and ductile metal resem-
bling tiii. Its sulphide, known as cadmium yellow, is bright in
color and has qualities of great value to artists. The metal
is of little use. Dentists make with it alloys and amalgams.
Calcium is yellow, ductile and malleable, and softer than
gold. At a red heat it burns with a dazzling white light.
Erbium is very rare ; it resembles aluminium in its proper-
ties and compounds.
Glucinum resembles aluminium, though lighter and un-
tarnishable. It excels iron in strength, and copper in con-
ductivity.
Lithium is a metal resembling silver in color. It admits
of being drawn into wire, but has little tenacity. It is
remarkable for its lightness and the readiness with which it
combines with oxygen.
Molybdenum is a silvery white, brittle and infusible metal.
It never occurs native, and neither it nor its compounds are
of practical use.
Osmium is remarkable for its high specific gravity and
infusibility.
COMMERCIAL METALS. 99
Palladium resembles platinum. An alloy of 20 per cent,
with 80 per cent, gold is perfectly white, very hard and does
not tarnish by exposure.
Rhodium is white, very hard and infusible. Its specific
gravity is about n.
Ruthenium resembles iridium. It is rare and of little
value.
Strontium is yellowish, ductile and malleable ; it burns in
the air with a crimson flame.
Thallium is very soft and malleable.
Thorium is an extremely rare metal, remarkable for taking
fire below red heat, and burning with great brilliancy. Neither
the metal nor its compounds are of practical use ; its oxide
has the high specific gravity of 9.4.
Titanium is a rare metal, usually obtained in crystalline
form, and also as a heavy iron-gray powder. The crystals are
copper-colored and of extreme hardness.
Tungsten is a hard, iron-gray metal, very difficult of
fusion. An alloy of ten per cent, of this metal and 90 per
cent, of steel is of extreme hardness. Both the metal and
its compounds have proved of value alloyed in steel and
bronze. Chromium has similar uses.
Uranium is very heavy and hard, but moderately mallea-
ble, resembling nickel and iron ; it is unaltered at ordinary
temperatures by air or water.
Rubidium and caesium so closely resemble platinum that
no ordinary test will distinguish them.
Indium is very soft, malleable and fusible ; it marks paper
like lead.
Barium, cerium, columbium (or niobium), didymium, lan-
thanium, tantalum, terbium, yttrium, and zirconium, are all
rare metals and not very well known.
59. The Commercial Metals are never chemically pure.
Lake Superior copper and the best lead and tin are practi-
cally so, but all other metals have such a variety of quality
and composition, as sold in our markets, that the purchaser
and consumer can only rely upon careful analyses to deter-
mine their value for any proposed use. This precaution is
100 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
especially advisable when the engineer selects metals or
alloys for use in construction.
Thus copper has been found to contain as much as 30
per cent, lead and 8 or 9 per cent, of nickel, iron, arsenic,
and other metals ; lead often contains several per cent, of
antimony, arsenic, zinc, and other elements ; iron may con-
tain besides the sulphur and phosphorus which frequently
seriously injure it, a considerable amount of manganese,
chrome, nickel and cobalt, and even copper ; platinum often
contains appreciable quantities of the other rare metals, as
paladium, rhodium, usually iridium and osmium, and some-
times iron and copper ; zinc is very frequently rendered use-
less for the engineer's purposes by the presence of lead.
The Prices of Metals are so constantly varying that no
list can be given of great accuracy. The cost of reduction,
the relations of supply and demand, and the accidental fluctu-
ations of the market combine to determine the exact figures.
The following table, mainly from Bolton,* may be taken as
representing approximate values.
PRICES OF METALS.
METAL.
STATE.
VALUE IN
GOLD PER LB.
AVOIRDUPOISE.
PRICE IN
GOLD, IQOO.
AUTHORITY.
Vanadium
Cryst. fused
$4. 7Q2 . 4O
$480
s
Rubidium .
Wire
3 261 60
2 4OO
s
Calcium
Electrolytic
2 44.6 2O
Q2O
s
Tantalum .
Pure
2 446 2O
684
s
Cerium
Fused globule
2 446 2O
Q2O
s
Lithium
2 22S 76
,y^u
060
s
Lithium
Wire
2 Q^S 44,
44O
s
E)rbium
Fused
671 ^7
s
Didymium
a
630.08
2 880
s
Strontium
Electrolytic
S76 44
I Q2O
s
Indium
Pure
522 08
72O
T
Ruthenium
3O4 64
I ^OO
T
Columbium . .
Fused
250 28
4HO
s
Rhodium
O32 . 84
I OOO
T
Barium . .
Electrolytic
O24 12
coo
s
Thallium
738 30
5UU
OCf)
T
Osmium
6t'> a2
VDU
T
Palladium
408. 3O
600
T
* Engineering and Mining Journal, Aug. 21, 1875.
THE PRICES OF METALS.
PRICES OF METALS. — Contimted.
101
METAL.
STATE.
VALUE IN
GOLD PER LB.
AVOIRDUPOISE.
PRICE IN
GOLD, igOO.
AUTHORITY.
Iridium
$466. 59
$480
T.
414.. 88
240
T.
Gold
2QQ 72
2, Q
Titanium . ....
Fused
2^o 80
Tellurium
ft
1 06 2O
*
«
196 20
T 7t
....
it
122 31
...
Manganese
«
IO8 72
T
Molybdenum
ZA -7/1
en
T.
Magnesium
AC on
IQC
T
Potassium ...
Globules
43 ' JV
22 65
g
T
Silver
18 60
j e
Aluminum *
Bar
16 30
•JQ
S.
Cobalt
Cubes
12.68
s.
Nickel
n
3 80
•1C
T.
Cadmium . .
^ 26
T.
Sodium
? 26
j
T.
Bismuth
Crude
I.QC
j
S.
Mercury
I .OO
j
Antimony ...
•*6
2O
T
Tin
2C
oe
.22
18
. 15
oc
Zinc
.IO
06
Lead
.06
Oli
•°5
The prices of many may be considered also as " fancy
prices," and a whole pound of some of the metals named
could hardly be obtained at even these figures. In compiling
the table, the prices of the rarer metals are obtained from
TrommsdorfFs and Schuchardt's price lists ; the avoirdupois
pound is taken as equal to 453 grammes, and the mark as
equal to 24 cents gold.
It is evident that the prices of the metals bear no relation
to the rarity of the bodies whence they may be derived ; for
calcium, the third in the list, is one of the most abundant
elements.
* The price of copper fell in 1885-86 to 10 cents per pound, rising in 1887
somewhat, aluminium (1896) has dropped to 50 cents or less ; magnesium to $5;
nickel to 25 cents a pound; silver to 50 cents an ounce; platinum, $6; while
7ead and zinc cost 3 and 4 cents a pound.
CHAPTER III.
PROPERTIES OF THE ALLOYS.*
60. Properties of Alloys. — The Author, before entering
upon the researches directed by the Committee on Metallic
Alloys of the United States Board, and before making a series
of experiments on the characteristics of alloys, as a proper
introduction to the work instituted a somewhat exhaustive
examination of the records of earlier experiments in this
direction.
The result of this investigation has been to reveal a vast
amount of information on the chemical and physical proper-
ties of the alloys ; but such information is widely scattered,
and authorities do not always agree. Some experiments have
been made upon alloys made from the impure commercial
metals, others from metals rendered chemically pure for the
purpose. Again, the apparatus used has not always been of the
same degree of accuracy, and this has produced another cause
of disagreement. These differences, however, are usually slight.
It is evident that alloys, being composed of metallic bodies,
will possess all the physical and chemical characteristics of
metals ; they have the metallic lustre, are more or less ductile,
malleable, elastic, and sonorous, and conduct heat and elec-
tricity with remarkable facility. In retaining these proper-
ties, however, the compound is so modified in some of its
qualities, that it often does not resemble either of its con-
stituents, and might, consequently, be regarded as a new
metal, having characteristics peculiar to itself. This is espe-
cially the case with those which are used in the arts. It would
* Prepared originally, in large part, and with the assistance of Mr. Wm.
Kent, M.E., for the Committee on Metallic Alloys of the United States Board,
appointed to test, iron, steel, and other metals. See Report, Vol I., 1878.
PROPERTIES OF THE ALLOYS. IO3
almost seem that there is no department of the arts requiring
the use of metals for which an alloy may not be prepared
possessing all the requisite qualities, when these are not found
in the original metals.* The physical properties of an alloy are
often quite different from those of its constituent metals. Thus
copper and tin mixed in certain proportions, form a sonorous
bell-metal, possessing properties in which both metals are
deficient ; in another proportion they form speculum metal,
which is as brittle as glass, while both of the constituent
metals are ductile. It is impossible to predict from the char-
acter of two metals what will be the character of an alloy
formed from given proportions of each. In most cases, how-
ever, it will be found that the hardness, tenacity, and fusi-
bility will be greater than the mean of the same properties in
the constituents, and sometimes greater than in either; while
the ductility is usually less, and the specific gravity is some-
times greater and sometimes less.f The color is not always
dependent upon the colors of the constituent metals, as is
shown by the brilliant white of speculum metal, which con-
tains 67 per cent, of copper.
Very slight modifications of proportions often cause very
great changes in properties. M. Bischoff \ states that he can
detect the deteriorating effect of one part tin upon ten million
parts of pure zinc, and the writer has found half of a per
cent, of lead to reduce the strength of good bronze nearly one-
half and to affect its ductility to an almost equal extent.
It is not a matter of indifference in what order the metals
are melted in making an alloy. Thus, if we combine 90 parts
of tin and 10 of copper, and to this alloy add 10 of antimony ;
and if we combine 10 parts of antimony with 10 of copper,
and add to that alloy 90 parts of tin, we shall have two alloys
chemically the same, but in other respects — fusibility, tenacity,
etc. — they totally differ. In the alloys of lead and antimony,
also, if the heat be raised in combining the two metals much
above their fusing points, the alloy becomes harsh and brittle.
* Muspratt's Chemistry, vol. I, p. 533.
f Ure's Dictionary, vol. I, pp. 46-50.
\ British Assoc. Reports, 2, 1870, pp. 209, 210.
104 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Some metallic alloys are much more easily oxidizable than
the separate metals. An alloy of tin and lead heated to red-
ness takes fire and continues to burn for some time.*
In regard to certain physical properties, Matthiessenf
remarks that the metals may be divided into two classes:'
Class A. — Those metals which impart to their alloys their
physical properties in the proportion in which they them-
selves exist in the alloy.
Class B. — Those metals which do not impart to their
alloys their physical properties in the proportion in which
they themselves exist in the alloy.
The metals belonging to class A are lead, tin, zinc, and
cadmium ; and those belonging to class B, in all probability,
all the rest.
The physical properties of alloys may be divided into three
classes :
I. Those which in all cases are imparted to the alloy
approximately in the ratio in which they are possessed by the
component metals.
II. Those which in all cases are not imparted to the alloy
in the ratio in which they are possessed by the component
metals.
III. Those which in some cases are and in others are not
imparted to the alloy in the ratio in which they are possessed
by the component metals.
As types of the first class, specific gravity, specific heat,
and expansion due to heat may be taken ; as types of the
second class, the fusing points and crystalline form ; and as
types of the third class, the conducting power for heat and
electricity, sound, elasticity, and tenacity.
61. The Chemical Nature of Alloys. — The chemical nat-
ure of alloys has long remained a disputed point among scient-
ists. The question, "Are alloys definite chemical compounds,
solutions, or mechanical mixtures?" is not easily answered.
Several authors give their views and describe their methods
of making experiments to settle this question, but there still
* Ure's Dictionary, vol. I, p. 49.
f Jour. Chem. Soc., vol. 5, 1867, pp. 201-220.
PROPERTIES OF THE ALLOYS. IO5
remains a wide difference of opinion in regard to it. Most
writers now agree, however, in considering some alloys as
chemical compounds and others as mixtures, but they differ
as to whether any particular alloy is the one or the other.
Thus Calvert and Johnson * consider the tin-copper alloys
definite compounds, while Matthiessenf claims that they are
" solidified solutions of one metal in the allotropic modification
of the other." Muspratt \ says:
Many alloys consist of simple elements in definite or equivalent
proportions, while others are produced from compound bodies, and
often the components do not exist in the ratio of their chemical
equivalents. Metals, in forming alloys, do not, however, combine
indiscriminately with one another ; the union is governed by the
greater affinities which some of them manifest for each other ; just
as, in the chemistry of bases and acids, a predisposing attraction
determines a preference. This in some measure proves that the
alloys are not mechanical mixtures, but definite chemical com-
pounds. It is remarkable that the native gold found in auriferous
sands and rocks is alloyed with silver in the ratio of one equivalent
of the latter to four, five, six, eight, ten, etc., equivalents of the
former, but the combinations never afford results indicative of the
metal being united in fractional parts of an equivalent.
Muspratt further says that another proof of the chemical
combination subsisting is, that the compound melts at a lower
temperature than the mean of its ingredients; but Mat-
thiessen § argues that this is no proof.
Watts 1 remarks that most metals are probably to some
extent capable of existing in combination with each other in
definite proportions ; but it is difficult to obtain these com-
pounds in a separate condition, since they dissolve in all pro-
portions in the melted metals, and do not generally differ so
widely in their melting or solidifying points from the metals
* Phil. Trans., 1858, p. 363. f British Assoc. Rep., 1863, p. 47.
\ Muspratt's Chemistry, vol. I, p. 534.
§ British Assoc. Rep. 1853, p. 42 ; also, Jour. Chera. Soc., vol. 5, 1867, p,
207.
J Watts' Dictionary, vol. iii. p. 942.
106 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
they may be mixed with as to be separated by crystallization
in a definite condition.
The chemical force capable of being exerted between different
metals may, as a rule, be expected to be very feeble, and the conse-
quent state of combination would therefore be very easily disturbed
by the influence of other forces. But in all cases of combination
between metals, the alteration of physical properties, which is the
distinctive feature of chemical combination, does not take place to
any great extent. The most unquestionable compounds of metals
are still metallic in their general physical characters, and there is no
such transmutation of the individuality of their constituents as takes
place in the combination of a metal with oxygen, or sulphur, or
chlorine, etc. The alteration of characters in alloys is generally
limited to the color, degree of hardness, tenacity, etc.
Messrs. Calvert and Johnson, about the year 1860, made
a long series of experiments on alloys and amalgams made
with pure metals, with the hope of throwing some light upon
the subject, and of solving the question " Are alloys mixtures
or compounds ? " They believe that they have succeeded in
ascertaining: First, the influence which each additional
equivalent quantity of a metal exerts on another; secondly,
the alloys which are compounds and those which are
simple mixtures; for compounds have special and character-
istic properties, while mixtures participate in the properties
of the bodies composing them. They hold that the bronze
alloys are definite compounds; for each alloy has a special
value of conductivity of heat, and also its own specific gravity,
and its own rate of expansion or contraction ; while, on the
contrary, the alloys of tin and zinc are mixtures ; for they
conduct heat, have a specific gravity and expand according
to theory, or according to the proportions of tin and zinc
which compose each alloy. Calvert and Johnson's con-
clusions are chiefly based upon their experiments on the
heat conductivity of the alloys. Later experiments, made by
Matthiessen,* on the conducting power of electricity, led him
* British Assoc. Reports, 1863, pp. 37-48.
PROPERTIES OF THE ALLOYS. IO/
to different conclusions. He experimented upon upwards of
250 alloys, all made of purified metals. The results of his
investigations are published in a paper, "On the Chemical
Nature of Alloys," from which is transcribed the following
classification of the solid alloys, composed of two metals,
according to their chemical nature.
1 . Solidified solutions of one metal in another :
The lead-tin, cadmium-tin, zinc-tin, lead-cadmium, and
zinc-cadmium alloys.
2. Solidified solutions of one metal in the allotropic modifi-
cation of another :
The lead-bismuth, tin-bismuth, tin-copper, zinc-copper,
lead-silver, and tin-silver alloys.
3. Solidified solutions of allotropic modifications of the metals
in each other :
The bismuth-gold, bismuth-silver, palladium-silver, plat-
inum-silver, gold-copper, and gold-silver alloys.
4. Chemical combinations :
The alloys whose composition is represented by Sn5 Au,
Sn2 Au, and Au2 Sn.
5. Solidified solutions of chemical combinations in one an-
other :
The alloys whose composition lies between Sn5Au and
Sna Au, and Sn2 Au and Au2 Sn.
6. Mechanical mixtures of solidified solutions of one metal
in another :
The alloys of lead and zinc, when the mixture contains
more than 1.2 percent, lead or 1.6 per cent. zinc.
7. Mechanical mixtures of solidified solutions of one metal
in the allotropic modification of the other :
The alloys of zinc and bismuth, when the mixture con-
tains more than 14 per cent, zinc or 2.4 per cent, bismuth.
8. Mechanical mixtures of solidified solutions of the allo-
tropic modifications of the two metals in one another:
Most of the silver-copper alloys.
Matthiessen, however, does not claim that the above
classification is not liable to exception. He was obliged to
assume that some of the metals undergo a change, or are
108 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
converted into an allotropic modification in the presence of
another metal, in order to explain some of the phenomena
which he observed, but he admits that until the allotropic
modifications have been isolated, the assumption must re-
main an hypothesis.
To conclude, we can only say that the question is still
unsettled. From the marked peculiarities of properties
observed in a few of the alloys, we are led to pronounce them
chemical compounds. Some others, we must admit, are
simple mixtures, or rather, solidified solutions. But in
regard to the large majority we are still in doubt. Further
experiments may throw more light on the subject, but it is
probable that with the larger number of alloys it will be
found impossible to discover their exact chemical nature.
62. Specific Gravity. — The specific gravity of an alloy is
rarely the mean between the densities of each of its constit-
uents. It is sometimes greater and sometimes less, indicat-
ing, in the former case an approximation, and in the latter
a separation of the particles from each other in the process of
alloying. This subject has been studied by several writers,
and their published results agree quite closely in regard to
some of the alloys, but differ in regard to others. These
differences may be accounted for by the differences in the
apparatus used by the experimenters, by the fact that some
determinations have been corrected for temperature and pres-
sure of the atmosphere, while others were not ; but principally
from the fact that several of the alloys are liable to be very
deficient in homogeneity, and that the density of the same
alloy will vary according to the conditions under which it is
formed, as being cast too cold or too hot, cast in iron or in
sand moulds, etc. A bar cast in a vertical position is apt to
have a greater specific gravity at the bottom of the bar than
at the top. Repeated fusion of an alloy also causes changes
in its density.
It is common among authorities who publish determina-
tions of specific gravities of the alloys, to give the calculated
as well as the observed specific gravity. The calculated
specific gravity is that which the alloy would .have ;f there
PROPERTIES OF THE ALLOYS. 1 09
were neither expansion nor condensation of the metals during
the act of combination. The specific gravities should be
calculated from the volumes and riot from the weights. Dr.
Ure* gives the rule as follows: Multiply the sum of the
weights into the products of the two specific gravity numbers
for a numerator, and multiply each specific gravity number
into the weight of the other body and add the products for
a denominator. The quotient obtained by dividing the said
numerator by the denominator is the truly computed mean
specific gravity of the alloy. Expressed in algebraic language
the above rule is —
M_(W+w)Pp
~ Pw + p W
where M is the mean specific gravity of the alloy, Wand w the
weights, and P and p the specific gravities of the constituent
metals.
Clarke's compilation of the " Constants of Nature," pub-
lished by the Smithsonian Institution, contains a full table
of specific gravities of the alloys, with the names of about
twenty-five authorities. Of these, the principal are Mallet,
Calvert and Johnson, Matthiessen, and Riche.
The following table of the alloys whose density is greater
or less than the mean of their constituents, is given by several
writers :
TABLE XVIII.
ALLOYS OF ABNORMAL DENSITY.
Alloys, the density of which is greater than
the mean of their constituents.
Gold and zinc.
Gold and tin.
Gold and bismuth.
Gold and antimony.
Gold and cobalt.
Silver and zinc.
Silver and tin.
Silver and bismuth.
Alloys, the density of which is less than the
mean of their constituents.
Gold and silver.
Gold and iron.
Gold and lead.
Gold and copper.
Gold and iridium.
Gold and nickel.
Silver and copper.
Iron and bismuth.
* Ure's Dictionary, 6th ed. 1872, vol. I, p. 92.
1 10 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XVIIL— Continued.
Alloys, the density of which is greater than
the mean of their constituents.
Silver and antimony.
Copper and zinc.
Copper and tin.
Copper and palladium.
Copper and bismuth.
Lead and antimony.
Platinum and molybdenum.
Palladium and bismuth.
Alloys, the density of which is less than the
mean of their constituents.
Iron and antimony.
Iron and lead.
Tin and lead.
Tin and lead.
Tin and palladium.
Nickel and arsenic.
Zinc and antimony.
Calvert and Johnson agree with Matthiessen in giving the
density of the alloys of lead and antimony as less than the
mean of the constituents, and Matthiessen shows the alloys
of lead and gold to have a greater density than the mean of
their constituents. Some alloys of tin and gold and of bis-
muth and silver are shown by Matthiessen to have a greater,
and some a less, density than the mean of their constituents,
and the same is true of the alloys of some other metals.
63. Fusibility. — A remarkable property of many of the
alloys is their great fusibility. In nearly all cases the fusing
point of an alloy is lower than the mean of its constituent
metals, and in some instances, as in the so-called fusible
alloys, it is lower than that of either. The cause of this fact
has not been definitely ascertained. Some regard it as a
proof that the alloy is a distinct chemical compound, but
most authorities differ from this view. Matthiessen* sup-
poses that chemical combinations may exist in the fused
mass, which suffer decomposition on cooling or solidifying.
He says that the low fusing points admit of explanation by
assuming that chemical attraction between the two metals
comes into play as soon as the temperature rises, and the
moment the smallest portions melt, then the actual chemical
compound is formed which fuses at the lowest temperature,
and then acts as a solvent for the particles next to it, and so
promotes the combination of the metals where this can take
place.
* British Assoc. Reports, 1863, p. 42.
PROPERTIES OF THE ALLOYS. Ill
In another place* Matthiessen remarks that all mixtures
have a lower fusing point than the mean of the substances
forming the mixture ; for instance, salt-water solidifies below
zero, and a mixture of the chlorides of sodium and potassium
fuse at a lower point than the mean of the fusing points of
the components.
Some alloys have been observed to fuse at one point and
solidify at a lower one ; for example, the tin-lead alloys,
which all solidify at 181° C, but the fusing point of which
varies with the different proportions of the component metals
from 181° C. to 292° C.
Concerning these alloys, Pillichodyf remarks as follows:
When the points of solidification are observed by immersing the
thermometer in the melted alloy, it usually exhibits, during the
passage of the mass from the liquid to the solid state, two stationary
points. This effect is due to the separation of one or other of the
component metals, while an alloy of constant composition still re-
mains liquid. This alloy corresponds to the composition Sn3 Pb.
An alloy richer in lead would first deposit lead, and an alloy con-
taining a larger proportion of tin would first deposit tin — the alloy
Sn3 Pb remaining liquid for a longer or shorter time, and ultimately
solidifying at 1 8 1 ° C. This temperature, therefore, corresponds to the
lowest melting point that can be exhibited by an alloy of tin and lead,
a larger proportion of either metal causing the melting point to rise.
With the exception of the alloys of tin and lead, and the
fusible alloys, the fusing points of but few of the alloys have
been determined. An accurate pyrometer for temperatures
above red heat is needed for this purpose. The " Constants
of Nature," while it has the specific gravities of several
hundred alloys, gives the melting points of only six, exclusive
of the fusible alloys and those of lead and tin. Mallet \
gives the relative fusibility of the several alloys of copper and
tin and copper and zinc, and shows that their fusibility in-
creases regularly as the proportion of copper in the alloy
diminishes.
* Jour. Chem. Soc., vol. 5, 1867, p. 207.
f Ibid., vol. 15, 1862, p. 30.
\Phil. Mag., vol. 21, 1842, pp. 66-68.
112 MATERIALS OF ENGINEERING— NON-FERROUS ME TALS.
Some alloys in passing from the liquid to the solid state
do not change at once, but remain for some time in a pasty
condition. Their temperature of solidification, therefore,
cannot be distinctly recognized. This is the case with an
alloy of the composition Bi2PbSn2, which is fusible in boil-
ing water, but which remains in a pasty condition through an
interval of several degrees of temperature, so that it can be
handled like a plaster.
M. Person* made experiments upon the alloys Bi3Pb2Sna
(D'Arcet's alloy, fusible at 96° C.), Bi2PbSn2 (fusible in boil-
ing water), and BiPbSn2 (fusible at 145° C.), and formed the
conclusion that it is possible to assign in advance the heat
necessary to fuse an alloy, if that required to fuse each of its
component metals is known. He gives the formula (160 + /)
$ — /, in which t is the temperature at which fusion is
effected ; for example, 332° C. for lead if melted alone, but
only 96° C. if melted in D'Arcet's fusible alloy ; / is the ex-
penditure of heat necessary to produce the fusion, that is, a
certain number of calories (i calorie — 3.96 British thermal
units) variable with /; S is the difference of the specific heats
of the liquid and solid. If t and /are known, 3 can be found.
In the case of tin, / = 235, / = 14.3, from which % — 0.0362.
Having this value of 5-, it is easy to calculate the heat neces-
sary to melt tin at any temperature whatever, for instance at
96° C., for which we find 9.3 cal. Making the same calcula-
tion for bismuth and for lead we find 7.382 and 2.7 cal. It
only remains to take these numbers in the proportion in
which each metal exists in the alloy, which gives a little less
than 6.3 calories, which differs from the number found by
experiment (6 cals.} only 0.3 cal.
Nothing appears to have been written upon this branch
of the subject since M. Person's paper was published, but it
is probable that if the investigation was pursued further our
knowledge of the causes of the remarkable fusibility of the
alloys would be much increased.
M. Riche f has determined the melting points of certain
* Comptes Rendus, vol. 25, 1847, pp. 444-446.
f Ann. de Chim., vol. 30, 1873, p. 351.
PROPERTIES OF THE ALLOYS. 113
alloys of tin and copper, by means of Becquerel's thermo-
electric pyrometer. He obtained concordant results with the
alloys SnCu3 and SnCu4, but with all other alloys the results
differed widely among themselves.
W. C. Roberts,* chemist to the British mint, has published
a series of determinations of the melting points of several
alloys of silver and copper. The temperature was estimated
by finding the amount of heat contained in a wrought-iron
cylinder of known weight which was dropped into the melted
alloy while in the furnace, and removed as soon as the mass
showed signs of solidifying. The specific heats of the iron
and of the alloy were the data used in the calculation. The
alloy, composed of 630.29 parts of silver and 369.71 parts
copper, corresponding to the formula AgCu, showed the
lowest fusing point, or 846.8° C. ; that of pure copper being
1330° C., and that of pure silver 1040° C.
64. Liquation. — Many of the alloys exhibit the phenom-
ena of liquation, or separation of the mass of melted metal
in the act of solidification into two or more alloys of different
composition. The resulting alloy, or mixture of alloys, is con-
sequently deficient in homogeneity. The causes of this
separation are as yet but imperfectly understood. Some
observations seem to show that an alloy of constant com-
position and of a comparatively high fusing point solidifies
first in crystals disseminated throughout the mass, while the
remainder of the melted metal remains fluid for a longer
time, and finally solidifies around and among these crystals.
This fact would tend to prove that the first alloy solidified
was a distinct chemical compound, but it has been shown
that crystals of exactly the same appearance have been
formed from two 'metals in a wide range of proportions.
The different circumstances under which the separated
alloys may be formed, such as the heat of the metal when
poured into the mould, and the fact of slow or of rapid cooling,
are known to have some influence upon the amount of liqua-
tion, or the difference of composition of different parts of the
same casting, but this influence is not exerted upon all alloys
*Proc. Roy. Soc., vol. 23, 1875, pp. 481-495.
114 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
in the same direction, some alloys being affected in one way
and some in another by the same manner of treatment. The
bronze alloys, such as gun-metal, are said to have the liqua-
tion diminished by rapid cooling. When the mass is cooled
slowly, bronze castings often show in the interior what are
called spots of tin, but which are really spots of a white alloy
of copper and tin, containing a larger percentage of tin than
the average of the whole casting. When slowly cooled, also,
the bottom of the casting is often found to contain a larger
percentage of copper than the top. When cooled rapidly,
however, as shown in the experiments of General Uchatius*
in casting cannon in chilled moulds, the liquation is reduced
to a minimum, and the resulting alloy is more homogeneous.
Levol f made some experiments on the liquation of the
alloys of silver and copper, and concluded that the only
homogeneous alloy of these two metals was the one whose
composition is 718.97 parts of silver and 281.07 parts of cop-
per, corresponding to the formula Ag3Cu2, and that all the
others are liable to more or less liquation. It has lately been
shown, however, by Mr. W. C. Roberts, \ chemist to the
British mint, that this alloy is only homogeneous when cooled
rapidly. If the cooling is slowly effected, its homogeneity is
disturbed, the external portions being slightly richer in silver
than the centre.
Mr. Roberts made several determinations of the liquation
of other alloys of silver and copper, and found that the
arrangement of an alloy is to a great extent dependent on
the rate at which it is cooled, and that several alloys of silver
and copper are, under suitable conditions, as homogeneous as
Level's alloy. The alloy of 925 parts silver and 75 parts
copper was found to be nearly homogeneous when cooled
very slowly, the composition of the corners and centre of a
cube 45 millimetres on a side showing a maximum difference
of only 1.4 parts in 1,000, while the same when cooled rapidly
showed a difference of 12.8 parts in 1,000.
* Ordnance Notes No. xl, Washington, D. C., 1875.
f Ann. de CAim., vol. 36, 1852, pp. 193-224.
\ Proc. Roy. Soc., vol. 23, 1875, pp. 481-495.
PROPERTIES OF THE ALLOYS. 1 15
Col. J. T. Smith * relates, in reference to some experiments
made by him on the alloy of silver and copper containing
91^3 per cent, of silver, that the separation of the constituent
parts of the alloy was not so much due to the rapidity or
slowness with which the heat of the fluid metal was abstracted,
as to the inequality affecting its removal from the different
parts of the melted mass in the act of consolidation. Thus, if
a crucible full of the melted alloy were lifted out of the furnace
and placed on the floor to cool, the surface of the melted
metal within it being well covered with a thick layer of hot
ashes, the lower parts of the mass after it had become solid
would be found to contain less silver in proportion than the
upper surface.
If, on the other hand, the crucible were left to cool while
imbedded in the furnace, the upper surface being exposed to
the air, then the lower parts would, after solidification, be
found finer than the upper surface.
Riche f has made several experiments on the liquation of
the alloys of copper and tin. He remarks that to manifest
the property of liquation, it is necessary to agitate the
crucible containing the melted alloy, at the moment of solidi-
fication, in order to separate the small crystals already formed.
The results obtained on the last product, remaining liquid in
a mass weighing 1,000 to 1,200 grammes, showed a remarka-
ble liquation of all the alloys of copper and tin except those
corresponding to the formulae SnCu3 and SnCu4
Several other alloys exhibit like phenomena to an even
greater extent than those above mentioned. Matthiessen
and Von Bose experimented upon alloys of lead and zinc
and bismuth and zinc, melting the metals together in various
proportions, and found that one end of a bar would have an
excess of one metal and the other end an excess of the other.
Alloys of copper and lead containing an excess of lead show
a liquation in a remarkable degree, the excess of lead partly
oozing out from the mass on cooling.
* Proc. Roy. Soc., vol. 23, 1875, pp. 433-435.
f Comptes Rendus, vol. 67, 1868, pp. 1138-1140, and vol. 30, 1873, pp.
351-419.
Il6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
65. Specific Heat.— The published determinations of the
specific heat of the alloys are not numerous. This results,
not from any difficulty of making the observations, but
probably because they have not been considered of such
practical importance as those of other properties, and partly,
also, because M. Regnault's * determinations, made in 1841,
and his deductions therefrom, are accepted as final.
M. Regnault determined the specific heat of two classes
of alloys ; first, those which at 100° C. are considerably re-
moved from their fusing points ; and, secondly, those which
fuse at or near 100° C. The specific heats of the first series
were so remarkably near to that calculated from the specific
heats of the component metals that he announced the fol-
lowing law :
" The specific heat of the alloys, at temperatures considerably
removed from their fusing point, is exactly the mean of the
specific heats of the metals which compose them.'"
The mean specific heat of the component metals is that
obtained by multiplying the specific heat of each metal by
the percentage amount of the metal contained in the alloy
and dividing the sum of the products for each alloy by 100.
A curious fact discovered in regard to these alloys is also
that the product of the specific heat of each alloy by its
atomic weight is sensibly constant, varying in the whole series
only from 40.76 to 42.05.
The second series of alloys, or those which fuse at a
temperature at or near 100° C., show a wide divergence from
the above law, the specific heats of all of these being much
higher than that calculated from their constituents. The
product of the specific heats by the atomic weights varied
also from 45.83 to 72.97.
Matthiessen f describes a simple arrangement of the dif-
ferential thermometer for the purpose of showing that the
specific heat of an alloy is the same as the mean of those of
its components.
66. Expansion by Heat. — The expansion of the alloys by
* Ann. de Chitn., vol. I, 1841, pp. 129-207.
\Jour. Chem. Soc., vol. 5, 1867, p. 205.
PROPERTIES OF THE ALLOYS. 1 1/
heat has been examined by Messrs. Calvert and Lowe, * with
a view to learn whether their expansion followed the law of
the proportions of their components. Four series of alloys
were examined, namely, those of zinc and tin, lead and anti-
mony, zinc and copper, and copper and tin. In each case
the expansion was less than that deduced by calculation from
their equivalents.
In alloys of copper with tin, it was found that where only
a small quantity of tin entered into the composition of a bar,
the expansion fell considerably below that of pure copper,
although the tin added has a much higher rate of expansion
than copper.
From experiments made by Messrs. Calvert and Lowe
upon the expansion of chemically pure metals, they conclude
that a very small proportion of impurity has a marked in-
fluence upon the expansion. Their results differed largely
from those of other experimenters who used only the com-
mercial metals ; but when they, too, used commercial metals,
the results agree.
The alloys upon which they experimented were also
formed from pure metals, and on account of the difficulty of
procuring these in sufficient quantity, the bars experimented
on were very small, being only 60 millimetres, or less than 2^
inches long. The apparatus used, however, as described at
length in the Chemical News, was so sensitive, that an ex-
pansion of -gTTFo"o °f an mcn could readily be observed.
If experiments were made upon alloys formed from the
ordinary commercial metals, it would probably be found that
their rate of expansion would differ considerably from that
of alloys formed from pure metals.
The molecular condition of a metal was observed to have
an important influence on the rate of expansion. The same
will no doubt be found true in the case of alloys.
Matthiessenf states that the expansion due to heat of the
metals takes part in that of their alloys approximately in the
ratio of their relative volumes. He gives a table of the
* Chem. News, vol. 3, 1861, p. 315.
f Jour. Chem. Soc., vol. 5, 1867, p. 206.
Il8 MATERIALS OF ENGINEERING— NON-FERROUS METALS
expansion of several alloys which tends to confirm his state*
ment.
67. Conductivity for Heat.— The power of the alloys to
conduct heat has been examined with great care by several
experimenters. The published results are not always con-
cordant, but the differences may be partially accounted for
by the various kinds of apparatus used, and the great influence
which small impurities and changes in molecular condition
and crystalline form exert upon conductivity.
The conducting power for heat in an alloy is found in
some cases to be the mean of the conducting power of the
component metals, and in others to apparently have no relation
whatever to such mean. As examples of the first case may be
cited the alloys of tin and zinc and tin and lead; and of the
second, the alloys of gold and silver and gold and copper.
From this circumstance it has been expected that the heat-
conducting power could be used as a means of determining
whether an alloy is a chemical compound or a simple mixture.
As before stated, however, the authorities differ widely on
this point.
Messrs. Weidemann and Franz,* in 1853, made some
experiments on the conducting power of the metals and of a
few of the alloys, using a thermo-electroscope as an appa-
ratus.
In 1858, Calvert and Johnson f made an extensive research
on alloys formed from pure metals, using an apparatus of their
own invention, by which the relative conducting power was
shown by the rise in temperature in a given time of a given
volume of water secured in a box at one end of the bar, while
the other end of the bar was heated to 90° C. They claim
that the method which they employed gave such consistent
results, that they were able to determine the influence exer-
cised on the conducting power of the metals by the addition
of I or 2 per cent, of another metal, and also to appreciate
the difference of conductivity of two alloys made of the same
metals and only differing by a few per cent, in the relative
* Pogg. Annalen, vol. 89, 1853, pp. 497-531.
\ Phil. Trans., 1858, pp. 349-368.
PROPERTIES OF THE ALLOYS.
proportions of the metals composing them. They found also
that the conducting power of metals was different when they
were rolled out into bars or cast, and that it was modified by
molecular arrangement or position of the axes of crystalli-
zation, as was shown by the different conducting power of
metals cast horizontally and vertically. Some curious results
were observed in regard to alloys of gold and silver. Silver
being the best conductor, its conductivity is rated as 1,000,
and that of gold the next, is 981 ; but gold alloyed with i per
cent, of silver has a relative conductivity of only 840.
The conduction of heat by alloys, according to Calvert
and Johnson, may be considered under three general heads :
1. Alloys which conduct heat in ratio with the relative
equivalents of the metals composing them.
2. Alloys in which there is an excess of equivalents of the
worse conducting metal over the number of equivalents of the
better conductor •, such as alloys composed of I Cu and 2 Sn, I Cu,
and 3 Sn, etc., and which present the curious and unexpected
rule that they conduct heat as if they did not contain a particle
of the better conductor, the conducting power of such alloys
being the same as if the bar was entirely composed of the
worse conducting metal. A not less remarkable fact is that
the alloys of a series, such as those of 2 equivalents of bis-
muth and I of lead, 3 Bi and I Pb, 4 Bi and I Pb, all conduct
heat alike, the various increasing quantities of lead exercis-
ing no influence on the conductivity.
The results obtained with this class of alloys are most im-
portant to engineers ; for it will be seen in the case of alloys
of brass and bronze that no increase is gained in the con-
ductivity of an alloy by increasing the quantity of a good
conductor; nay, in many cases it would be a decided loss,
unless a sufficient quantity of the better conducting metal be
employed to bring the alloy under the third head.
3. Alloys composed of the same metals as the last class, but
in which the number of eqiiivalents of the better conducting
metal is greater than the number of equivalents of the worse
conductor ; for example, alloys composed of I Sn 2 Cu, I Sn
3 Cu, etc. In this case each alloy has its own arbitrary con-
120 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
ducting power; the conductivity of such an alloy gradually
increases and tends toward the conducting power of the
better conductor.
In a later experiment upon the conductivity of mercury
and the amalgams, Calvert and Johnson* discovered that
they had committed an error in their first experiments in
determining the conductivity of mercury, by disregarding the
fact that convection of the liquid increased the apparent con-
ductivity. In the first experiments they found the apparent
relative conductivity to be 677, silver being 1,000; but in the
later experiments they determined the real relative con-
ductivity to be only 54, or less than that of any other metal.
In regard to the fluid amalgams, they found in all cases that
their conductivity was nearly the same as that of pure mer-
cury.
Weidemann,f in 1859, published a paper in which he calls
in question the accuracy of the results found by Calvert
and Johnson, and criticises the apparatus used by them and
the small size of the bars upon which they experimented. He
also gives the results of some experiments which he has made
upon the conductivity of a few alloys.
Matthiessen \ describes a simple apparatus for showing
the different conductivities of alloys. He also states that the
conductivity for heat furnishes no evidence of whether an
alloy is a chemical compound or a mixture.
68. Conductivity for Electricity. — The conductivity for
electricity, like the conductivity for heat, is one of the prop-
erties which, in some alloys, is the mean of that of the com-
ponent metals, and in others seems to have no relation what-
ever to such mean.
There have been a large number of experiments made
upon the electric conductivity of the alloys, but in this, as in
the examination of other properties, with widely varying
results. In the first place, the determinations of the con-
ducting powers of the metals themselves are far from agree-
* Phil. Trans., 1859, PP« 831-835.
\ P°£g' Annalen, vol. loS, 1859, pp. 393-406.
\ Jour. Chem. S0c.,vol. 5, 1867, p. 213.
PROPER TIES OF THE ALLO YS. 121
ing ; as, for instance, the conductivity of copper, according
to different experimenters, is given at numbers ranging from
66 to 100, pure silver being 100.
Again, Matthiessen * has shown that small traces of the
metals, and especially of the metalloids, reduce the conduc-
tivity of copper to a great extent. He states also, that there
is no alloy of copper which conducts electricity better than
pure copper, and that the fact of the wires experimented
upon being annealed or hard drawn causes a marked differ-
ence in the values obtained, annealed wire being a better
conductor than hard drawn ; and, further, that temperature
has likewise a marked influence, the metals losing in conduct-
ing power as the temperature increases.
In 1833, Professor Forbes f published the statement that
the order of conducting powers of the metals for heat and for
electricity is the same. He states, as a general conclusion,
"that the arrangement of metallic conductors of heat does
not differ more from that of those of electricity than eithef
arrangement does alone under the hands of different ob-
servers."
Twenty years later, Weidemann and Franz ^ arrived at the
same conclusion in regard to brass and German silver, and
Weidemann, § in 1859, concluded the same in regard to alloys
in general. Weidemann and Franz remarked that whatever
the quality may be upon which calorific conduction depends,
the close agreement of the figures renders it exceedingly prob-
able that the same quality influences in a similar manner
the transmission of electricity; for the divergence of the
numbers expressing the conductivity for heat from those ex-
pressing the conductivity for electricity are not greater than
the divergences of the latter alone, exhibited by the results
of different observers.
The most extensive series of investigations upon the
electric conductivity of alloys has been made by Matthiessen.
* Phil. Trans., 1860, pp. 85-92.
f Phil. Mag., vol. 4, 1834, p. 27.
\ Pogg. Annalen, vol. 89, 1853, pp. 497-531.
§ Ibid., vol. 1 08, 1859, PP- 393-407.
122 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
His results are published in the following papers: "On the
Electric Conducting Power of the Metals ;" * " On the Elec-
tric Conducting Power of Alloys ;"f " On the Influence of
Temperature on the Electric Conducting Power of Alloys ;" £
"On the Thermo-Electric Series ;"§ "On the Effect of the
Presence of the Metals and Metalloids upon the Electric
Conducting Power of Pure Copper;"] "On the Chemical
Nature of Alloys." T
It was chiefly from these researches that Matthiessen
arrived at the conclusions in regard to the question whether
alloys are chemical compounds or mixtures, which have
already been given under the head of the chemical nature
of alloys.
Matthiessen's examination of the conductivity of copper,
made in 1860, greatly stimulated the refinement of the metal
used in telegraphy and led to a gradual improvement, from
a conductivity of less than 50 per cent, up to above 98 per
cent., that of pure copper in the latest work. Good wire has
highest conductivity when soft, but the strength of soft cop-
per is often much less than one-half that of hard drawn wire.
Use has no apparent effect on conductors of this metal, but
it is at times subject to a peculiar change resulting in brittle-
ness and loss of conductivity; this is especially liable to
occur in electro-magnets.
In regard to the conducting power for electricity of the
alloys, Matthiessen divides the metals into two classes :
Class A. — Those metals which, when alloyed with one
another, conduct electricity in the ratio of their relative
volumes.
Class B. — Those metals which, when alloyed with one
of the metals belonging to class A, or with one another,
do not conduct electricity in the ratio of their relative
* Phil. Trans., 1858, pp. 383-387.
f Phil. Trans., 1860, pp. 161-176.
J Phil. Trans., 1864. pp. 167-200.
§ Phil. Trans., 1858, pp. 369-381.
| Phil. Trans., 1860, pp. 85-92.
*T British Assoc. Reports, 1863, pp. 37-48.
PROPERTIES OF THE ALLOYS. 123
volumes, but always in a lower degree than the mean of
their volumes.
To Class A belong lead, tin, zinc, and cadmium. To class
B belong bismuth, mercury, antimony, platinum, palladium,
iron, aluminium, gold, copper, silver, and in all probability
most of the other metals.
69. Crystallization. — The crystallization of alloys exhibits
some curious phenomena. It was formerly supposed that if
a distinct crystal of an alloy were found, it would have a
definite chemical composition, and would show that the alloy
was not a mixture, but a veritable chemical compound.
In 1854, however, Prof. J. P. Cooke* published a paper
on two crystalline compounds of zinc and antimony, which
exhibited such properties as justified him in considering
them definite chemical compounds. To distinguish them, he
gave them the names of Stibiotrizincyle, with the formula Sb
Zn3, and Stibiobizincyle, with the formula SbZn2. In the
paper named, the crystalline form and other properties are
fully described.
A short time afterward it was found that well-defined
crystals, like those described as SbZn3, were obtained from
the alloys containing between 43 and 60 per cent, of zinc ;
and even in alloys of a higher zinc percentage crystals of the
same form were still seen, although they were no longer well
defined. In the alloys containing between 20 and 33 per
cent, of zinc, well-defined crystals, like those described as Sb
Zn2, were formed ; and finally, there separated from the
alloys containing between 33 and 42 per cent, of zinc, thin
metallic plates, which evidently belonged to the same crys-
talline form, f
The same fact has been observed by Matthiessen and Von
Bose \ in regard to the alloys of gold and tin, namely, that
well-defined crystals are not limited to one definite propor-
tion of the constituents of an alloy, but are common to all
gold-tin alloys containing from 43 to 27.4 per cent, of gold.
* Am. Jour. Art and Sci., vol. 18, 1854, pp. 229-237.
f Ibid., vol. 20, 1855, pp. 222-238.
J Proc. Roy. Soc., i86o-'62, pp. 433-436.
124 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
They also found in the case of these alloys that the crystals
and the mother liquor were never of the same composition,
the percentage of gold in the mother liquor being much below
that in the crystals.
From experiments by F. H. Storer,* it appears that the
alloys of copper and zinc yield crystals, sometimes exhibiting
distinct octahedral faces, sometimes in confused aggregates
of crystals, but all of octahedral character, and bearing a
striking resemblance to the crystals of pure copper obtained
by fusion. None of the crystals were found to contain a
larger proportion of either metal than the remainder of the
molten liquid from which they had separated. Storer con-
cludes that all the alloys of copper and zinc crystallize in the
regular system, and that they are not definite atomic com-
pounds, but merely isomorphous mixtures of the two metals.
Calvert and Johnsonf have also noticed the crystallization
of the alloys of copper and zinc, and state that it is probable
that Cu2Zn and Cu3Zn are definite compounds, as they are
perfectly crystallized, and have also a special heat-conducting
power of their own. They state that the most splendid of
all the brass alloys is the alloy CuZn, which is of a beautiful
gold color, and crystallizes in prisms often 3 centimetres long.
Slow cooling of an alloy is apt to favor the separate crys-
tallization of one or more of its components, and thus render
k brittle. Sometimes in casting an alloy in large masses,
there will be a partial separation of the constituents, and
crystals of different composition will be found at the top and
bottom of the mass, those at the bottom usually containing
the larger percentage of the metal which has the greater
specific gravity. This phenomenon has already been noted
under the head of liquation.
70. Oxidation and Action of Acids. — But few experiments
have been made to determine the rate of oxidation or cor-
rosion of the alloys by atmospheric influences or by the action
of acids. It is generally found that the action of the atmos-
phere is less on alloys than on their component metals. An
* " Memoirs of the American Academy," vol. 8, 1863, pp. 27-56.
f Phil. Trans., 1858, p. 367.
PROPERTIES OF THE ALLOYS. 12$
instance of this is the ancient bronze statues and coins, some
of the latter of which have their characters still legible,
although they have been exposed to the effects of air and
moisture for upward of twenty centuries.
The action of the atmosphere on an alloy heated to a
high temperature is sometimes quite energetic, as is shown
in the alloy of three parts lead and one of tin, which, when
heated to redness, burns briskly to a red oxide. When two
metals, as copper and tin, are combined, which oxidize at
different temperatures, they may be separated by continued
fusion with exposure to the air. Cupellation of the precious
metals is a like phenomenon.
Mushet* found that unrefined copper resisted the action
of muriatic acid better than pure copper. This he thought
was due to the presence of tin in the unrefined copper, as he
found that an alloy of copper containing about 3 per cent, of
tin resisted the action of acid to still greater extent. The
latter he recommends for the purpose of ship-sheathing.
Calvert and Johnsonf have made several experiments to
determine the action of nitric, hydrochloric, and sulphuric
acids upon alloys of copper and zinc and copper and tin.
Some of the results thus obtained were entirely unexpected.
Nitric acid of 1.14 specific gravity was found to dissolve the
two metals in an alloy of zinc and copper in the exact pro-
portion in which they exist in the alloy employed, while an
acid of i. 08 specific gravity dissolved nearly the whole of the
zinc and only a small quantity of the copper. Hydrochloric
acid of 1.05 specific gravity was found to be completely
inactive on all alloys of copper and zinc containing an excess
of copper, and especially on the alloy containing equivalent
proportions of each metal. Zinc was found to have an ex-
traordinary preventive influence on the action of strong
sulphuric acid on copper.
The alloys of copper and tin were all found to resist the
action of nitric acid more than pure copper, but the preven-
* Phil. Mag., vol. 6, 1835, pp. 444~447-
\ Ibid., vol. 10, 1855, pp. 250, 251; also, Jour. Chem. Soc., vol. 19, 1866,
pp. 434-454-
126 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
tive influence of tin presents the peculiarity that the action
of the acid increases as the proportion of tin increases ; thus
the alloy CuSn5 is attacked ten times more than the alloy Cu
Sn. The alloys SnCu2 and SnCu3 were attacked by strong
sulphuric acid with more violence than any other of the
bronzes.
Three alloys, viz., Cul8ZnSn, CuIOZnSn, and Cu4Zn2,
were found to be only slightly attacked by strong nitric or
hydrochloric acids, and not at all by sulphuric acid. The
resistance to the action of nitric acid is remarkable, as its
action on each of the component metals is very violent.
A. Bauer* has also published, in the Berichte der deut-
schen chemiscken Gesellschaft, the result of some experiments
on the action of hot sulphuric acid on several alloys of lead.
These experiments show that the addition of a little antimony
or copper renders the alloy more able to resist sulphuric acid,
while bismuth has a decidedly injurious effect.
71. Hardness and other Mechanical Properties. — The
mechanical properties of the alloys, such as hardness, mallea-
bility, ductility, resistance to strains of tension, compression,
and torsion, elasticity, resilience, etc., are of the utmost im-
portance to the engineer, but, at the same time, it is most
difficult to find reliable information regarding them. But
few experimenters of authority have investigated the subject,
and their researches, although valuable as far as they go, are
too limited in extent to allow of, a complete classification and
comparison. A few alloys which are of special service in the
arts have been well studied by those who have had occasion
to use them, with a view to learn their mechanical properties,
not as a matter of scientific interest, but as an actual necessity.
This has been the case especially with the various gun-metals,
upon which many experiments have been made under
authority of the different governments, so that among all the
alloys our knowledge of the gun-metals is the most extensive
and accurate. In like manner the properties of journal and
anti-friction metals have been investigated by those who are
concerned in their manufacture and use.
* Scientific American, vol. 33, 1875, p. 135.
PROPERTIES OF THE ALLOYS.
With these, and a few other exceptions, however, our
information on the mechanical properties of the alloys is very
meagre. It has been the endeavor of the Author, as far as
possible, to supply this manifest want by a series of experi-
ments on a large number of alloys, testing them to deter-
mine their mechanical properties.
The hardness of some of the alloys has been investigated
by Calvert and Johnson.* They used an apparatus for
determining the hardness, which consists, chiefly, of a conical
steel point of a certain size, which is pushed into the material
whose hardness is to be determined a given distance by
means of weights applied at the end of a lever. The relative
hardness is shown by the weight required for the different
materials.
A somewhat similar apparatus was used by Major Wade f
in determining the hardness of gun-metal, but he used a
diamond-shaped point and a fixed weight, determining the
relative hardness by the distance which the point was pushed
into the metal. General Uchatius,J in experiments for the
Austrian Government, used an indenting tool, which was
forced into the metal to be tested by a weight of 4.4 pounds
falling through a height of 9^ inches. The shorter the cut
made by the indenting tool, the greater the hardness.
Mallet § in 1842, in his experiments on the alloys of cop-
per and tin and copper and zinc, determined their tensile
strength, and also the order of their ductility, malleability,
and hardness. In his work on the " Construction of Artil-
lery," || published in 1856, the same author discusses the
physical and mechanical properties of gun-metal, showing
the effects of sudden and of rapid cooling, and the deteriorat-
ing effect of small proportions of a third metal, such as iron,
zinc, lead, or antimony.
In regard to the extent of our knowledge upon these sub-
* Phil. Mag., vol. 17, 1859, pp. 114-121.
f " Report of Experiments on Metals for Cannon," Phila., 1856.
\ Ordnance Notes No. XL., Washington, D. C, 1875.
§ Phil. Mag., vol. 21, 1842, pp. 66-68.
|| Mallet, "Construction of Artillery," London, 1856, pp. 80-101.
128 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
jects, he remarks : " Gun-metal, probably the very earliest
used material for cannon, is that which has received the least
improvement or systematization of our knowledge as to its
use, up to the present time ; the archaeologist finds the rude
weapons of Scandinavian, Celtic, Egyptian, Greek, and Ro-
man warfare formed of nearly the same alloys of copper and
tin, and in about the same proportions, as the cannon of to-day."
The circumstances of chief difficulty and importance in
the manipulation of gun-metal, as affecting the production of
cannon, are :
1st. The chemical constitution of the alloy, as influencing
the balance of its hardness, rigidity, or ductility, and tenacity.
2d. Its chemical constitution, and what other conditions
influence the segregation of the cooling mass of the gun,
when cast, into two or more alloys of different and often
variable composition.
3d. The effects of rapid and of slow cooling, and of the
temperature at which the metal is fused and poured.
4th. The effects due to repeated fusions, and to foreign
constituents, in minute proportions, entering into the alloy.
The circumstances of manipulation, as above named, have
already been shown to have a vast influence upon nearly all
the properties of the alloys, and their study is of the greatest
importance, not only in reference to gun-metals, but to all
alloys which may be used as materials of construction.
In connection with the subject of gun-metal, the experi-
ments lately made by General Uchatius * for the Austrian
Government are of interest. He found that the tenacity,
elasticity, and hardness of bronze were increased to an extra-
ordinary degree by driving a series of conical steel mandrels
or plugs, gradually increasing in size, into the bore of the
gun. The metal in the interior of the gun was thus stretched
or strained much beyond its elastic limit, and was thereby
given a new molecular condition, which enables it better to
resist both the expansive force of the exploded powder, and
the abrading effects of the shot.
The results of the experiments of General Uchatius have
* Ordnance Notes No. XL., Washington, D. C., 1875.
PROPERTIES OF THE ALLOYS. I2Q
been communicated to the Ordnance Department of the
United States by Col. T. T. S. Laidley, U. S. A., who calls
attention to the fact that experiments were made upon
bronze, with a view to improve its quality for guns, by Mr.
S. B. Dean, of Boston, in 1868-69, at which time he used
the identical mode of improving the bronze adopted by
General Uchatius some four years later. Patents for the
improvement were secured in May, 1869, not only in this
country, but also in England, France, and Austria. The
want of funds rendered it necessary for Mr. Dean's experi-
ments to be discontinued. This matter will be considered at
greater length in a later division of this volume.
9
,
[too ibriJ
.
CHAPTER IV.
THE BRONZES AND OTHER COPPER-TIN ALLOYS.
72. The Alloys of Copper, with smaller quantities of the
more common metals, are the most valuable and the most
common, and the most extensively used of all compounds or
mixtures known to the engineer and the metallurgist. Those
which are produced by the union of copper and tin are
generally classed as the " Bronzes." When copper is alloyed
with zinc, the composition is known as " Brass." These terms
are not exclusively so applied, however, and the term brass is
not infrequently used to cover the whole series of alloys com-
posed, wholly or in part, of alloys of copper and tin, copper and
zinc, or combinations of brass and of bronze with each other
or with less quantities of other metals. Bronzes are here sup-
posed to contain principally copper and tin. These alloys are
produced by the union, either chemically or by solution, when
molten, of two or more metals. Nearly all metals can unite
with nearly all other metals in this manner, and the number of
possible combinations is infinite ; nevertheless, but few alloys
are found to be very generally used in the arts. It is consid-
ered probable that the metals may combine chemically in
definite proportions, but the compounds thus produced usually
dissolve in all proportions in either of the constituents, and it
is rarely possible to separate the chemically united portions.
In some cases the affinity is very slight, as between lead and
zinc, either of which will take up but about one and a half per
cent, of the other. The alloys are usually the more stable as
their constituents are the more dissimilar, and, when this dif-
ference is chemically great, the compound becomes brittle.
Occasionally, an alloy is formed which gives evidence of the
occurrence of chemical union, by the production of heat; this
is seen in some copper-zinc alloys.
BRONZES AND OTHER COPPER TIN-ALLOYS. 131
Copper alloys are formed with nearly all metals with great
facility, and with no other precaution than that of either
preventing access of oxygen to the molten mass, or of thor-
oughly fluxing the alloy, to take up such as may have com-
bined with it. Many of these alloys were once considered
chemical compounds ; but the view which seems most gener-
ally accepted, at the present time, is that they are almost in-
variably either mere mixtures, or that a species of solution of
the one metal in the other takes place.
The most minute trace of foreign element often produces
an observable, or even an important, alteration of the proper-
ties of copper. This is especially true of its conductivity for
electricity, which is reduced greatly by an exceedingly minute
proportion of iron or lead.
73. History. — The alloys of these metals were used ex-
tensively by the ancients for coins, weapons, tools and orna-
ments, and the composition of their bronzes, as shown by
recent analyses, indicates that they were as skilful in brass-
founding as the modern workman.
Thus, Phillips gives the following as the results of his own
examinations and as showing the proportions of the constit-
uents employed in the manufacture of brass, at times both
preceding and closely following the Christian era :
•j
M
DATE.
PH
ZINC.
TIN.
LEAD.
IRON.
8
Large brass of the Cassia family
B C 2O
82 26
17-31
.qc
" " Nero '*
A D 60
8 1 07
I 05
" " Titus "
" 7Q
83 04
15 84
CQ
" Hadrian " ..
" 120
8<v67
10.85
1. 14
1-73
•74
" Faustina "
" 165
79.14
6.27
4-97
9.18
.23
Thus, copper and zinc were the essential constituents of
the alloys examined ; but then lead was sometimes present in
considerable quantities, together with tin and iron. Although
zinc occurs in such considerable quantities in these alloys, it
132 MATERIALS OF ENGINEERING— NON-I ERROUS METALS.
was not known in the metallic state until about the thirteenth
century, when it was described by Albert of Bollstadt.
Many analyses of ancient articles of bronze have been
made, and our knowledge of this very old alloy is consider-
ably greater than that of the alloys of zinc. The proportion
of the constituent metals was varied according to the purpose
to which the alloy was to be applied, as will be seen from the
following analyses, the hardness being modified according to
the proportion of tin present. The alloys containing the
largest amount of tin were used for mirrors, while those of
medium hardness were used for sword-blades and other cut-
ting instruments :
COPPER.
TIN,
LEAD.
IRON.
COBALT.
ANALYST.
i. Chisel, from ancient Egyptian quarry.
2. Bowl from Nimroud
94.00
5.90
.10
Wilkenson.
Dr Percy
3. Bronze overlaying iron
88.37
11.33
4. Sword-blade, Chertsey, Thames
89.69
88 05
9-58
•33
T. A. Phillips.
Prof Wilson
6 Celt
8 1 IQ
18 31
3
7. Roman As, B.C. 500
8. Julius Caesar .
69.69
m
8.00
21.82
12. 8l
•47
57
J. A. Phillips.
The third specimen was analyzed by Dr. Percy, who de-
scribes it as a small casting in the shape of the foreleg of a
bull, forming the foot of a stand, consisting of a ring of iron
supported upon three bronze feet. A longitudinal section
disclosed a central core of iron, around which the bronze had
been cast.
Some writers, to account for the immense masses of hard
stone wrought by the Egyptians and ancient Americans, sup-
pose that they possessed means of hardening bronze to a
degree equal to that of our steel ; this requires confirmation,
since no remains of bronze of such a hard variety have ever
been discovered.
The bronze weapons discovered by Dr. Schliemann among
the ruins excavated by him at or near the site of ancient
Troy* were often of nearly the composition of modern gun-
bronze ; they contained copper 90 to 96, tin 8.6 to 4. The date,
* " Troy and its Remains ;" London and New York, 1875 ; p. 361.
BRONZES A ND O THER COPPER- TIN ALLOYS. 133
archaeologically, is at the beginning of the "bronze age," and
immediately at the close of the " stone age." Sir John
Lubbock finds the bronze implements and ornaments of the
bronze age as remarkable for their beauty and variety as for
their utility.* They consisted of axes, arrow-heads, knives,
swords, lances, sickles, ear-rings, bracelets, rings, etc., etc.
The bronze used by the prehistoric nations contained no
lead ; that of the Romans and post-Romans was rarely of
pure copper and tin, but were usually more or less alloyed
with lead. Silver, zinc, and lead was not known in the
bronze age. The prehistoric bronzes were cast, sometimes in
metal or in stone, and sometimes in sand, moulds. A more
common method was by wax models, or " patterns," which
were used to make the desired cavity in an earthen or sand
mould, the wax being melted out afterward.
According to Charnay,f the Aztecs discovered a means of
tempering copper, and of giving to it a considerable degree
of hardness, by alloying it with tin. Copper hatchets were
known among them ; since Bernal Diaz states in the narrative
of his first expedition to Tobasco, that the Spaniards bartered
glass-ware for a quantity of hatchets of copper, which at first
they supposed to be gold. Copper abounded in Venezuela,
and we still find there in great numbers trinkets of copper
mixed with gold, or of pure copper, representing crocodiles,
lizards, frogs and the like.
In cutting down trees, they employed copper axes like
our own, except that, instead of having a socket for the haft,
the latter was split, and the head of the axe secured in the cleft.
The hatchet described seems to have been a piece of
native copper wrought and fashioned with a stone ham-
mer. The Aztecs made good bronze chisels, as described
by Seftor Mendoza, director of the National Museum of
Mexico. He describes certain specimens of bronze chisels
belonging to the collection in that museum. When freed
from oxide the bronze presents the following characteristics:
In color it resembles gold ; its density is 8.875 I lt is
* " Prehistoric Times ; " London and New York, 1872.
\ N. A, Review, 1875 > Ruins of Central America.
J34 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
able, but unlike pure copper, is hard, and breaks under strong
tension or torsion ; the fracture presents a fine granulation
like that of steel ; in hardness, it is inferior to iron, but it is
sufficiently hard to serve the purpose for which it was in-
tended. One of these chisels was found to consist of coppef
97-87 per cent, tin 2-13 per cent., with traces of gold and
zinc.
The bronzes were used by the ancients in the manufacture
of weapons and of tools. The use of phosphorus increases the
purity and adds strength and hardness to these alloys, and
the remarkable hardness of ancient bronze weapons is found
by Dr. Reyer to be due, in part at least, to the presence of
phosphorus, probably introduced with the flux used in melt-
ing. The proportion of tin varied up to 20 per cent.
74. The Alloys of Copper and Tin have many uses in the
arts. The two metals will unite to form a homogeneous alloy
in a wide range of proportions. As tin is added to pure cop-
per, the color of the alloy gradually changes, becoming
decidedly yellow at 10 per cent, tin and turning to gray as
the proportion approaches 30 per cent. In the researches
conducted by the Author, it was found that good alloys may
contain as much as 20 per cent. tin. When the color changes
from golden yellow to gray and white, the strength as suddenly
diminishes ; and alloys containing 25 per cent, tin are valueless
to the engineer; nevertheless, this alloy and those contain-
ing up to 30 per cent, show compressive resistances increas-
ing to a maximum. The tensile and compressive resistances
have no known relation ; the torsional resistance is more
closely related to tenacity.
A small loss of each constituent occurs in melting, the loss
often being highest with the metal present in the lowest
proportion ; this loss rarely exceeds one per cent., except when
the fusion has taken place slowly with exposure to the air, when
considerable copper-oxide is liable to form. The specific
gravities of these alloys do not differ much from 8.95.
Under 17.5 per cent, tin, the elastic limit lies between 50
and 60 per cent, of the ultimate strength ; beyond this limit
the proportion rises, and at 25 per cent, tin the elastic limit
BRONZES AND OTHER COPPER-TIN ALLOYS. 135
and breaking point coincide. Passing 40 per cent, tin, this
change is reversed and the elastic limit, although indefinite,
is lowered until pure tin is reached and a minimum at
about 30 per cent.
The modulus of elasticity of all the bronzes lies between
ten and twelve millions.
Riche states that tempering produces on steel, forged or
annealed, an inverse effect to that which it produces on
bronzes rich in tin ; it diminishes its density instead of in-
creasing it, from which it may be seen that tempering
diminishes the density of annealed steel and makes it hard,
while tempering increases the density of annealed bronze and
makes it soft.
There is always an increase in density, whether the bronzes
rich in tin be tempered, or slowly cooled, after compression.
These experiments confirm most clearly the fact affirmed
by D'Arcet, that tempering softens the bronzes, rich in tin,
for we can flatten in the press the tempered bronzes, while it
is impossible to do this with steel.
It is evident from his experiments that tempering aug-
ments considerably the density of bronze rich in tin, and that
annealing evidently diminishes the density of tempered
bronze. Still the effect of slow cooling by no means destroys
the effect of tempering, for the density continues to increase
till it becomes remarkable.
While all mechanical action increases the density of the
annealed bronze, it very slightly, but still sensibly, diminishes
the density of annealed steel, and, on the whole, tempering
and shock increase the density of annealed bronze, while
they diminish the density of annealed steel.
But the variations are very decided for bronze and very
slight for steel.
Bronze of 96 and 97 parts copper may be employed to
great advantage, and with no serious inconvenience, in the
manufacture of medals. Its hardness, much less than that of
the alloy of M. de Puymaurin, does not much exceed that of
copper ; it possesses a certain sonority and casts well, rolls
evenly, and its color is more artistic than that of copper.
136 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The action of the press and of heat modify its density
but little.
75. Properties. — Copper and tin alloy in all proportions,
and the most useful compounds known to the engineer are
the u bronzes," as these alloys are called. They include gun-
metal, bell-metal and speculum alloys. The following is
Mallet's list of these alloys and table of their properties.*
TABLE XIX.
PROPERTIES OF COPPER-TIN ALLOYS.
At. wt. : Cu. =31.6; Sn =58.9.
AT. COM P.
COPPER.
S. G.
COLOR.
FRACT.
TENACITY.
MALL.
HARD.
FUS.
Cu Sn
I 0
a 10
b g
per ct.
too.
84.23
82.8;
8.607
8.561
8.462
red-yellow
yellow-red
fine grain
Tons per sq. in.
24.6
16.1
15.2
I
2
3
10
8
5
16
15
H
c 8
d 7
81.10
78.97
t:JS
pale red
vitreous
17.7
13-6
4
5
4
3
»3
12
e 6
76.29
8.750
u
•*
9.7
brittle
2
TI
f 5
72.80
8-575
ash gray
conchoid.
4-9
10
y
t 2
68.21
61.69
51-75
8.400
8-539
8.416
dark gray
white gray
white
lam. grain
0.7
o.S
i.7
friable
11
brittle
6
7
9
I
7
J I
34-92
8.056
vitreous
'•4
fck
ii
6
k I
21.15
7-387
lam. grain
3-9
'•
12
5
/ i 3
15-17
7-447
"
3-1
8 tough
13
4
vi i 4
11.82
7.472
"
3-1
6 "
H
3
n i 5
9 63
7.442
earthy
2-5
7
2
o o i
o.
7.291
2.7
16
i
«, b, c are gun-metals ; d^ hard brass for pins ; «•, f, g, h, /, bell-metal ; /, /£, for small
bells ; /, m, n, o, are speculum alloys.
The addition of a small quantity of tin to copper causes it
to become brittle under the hammer, according to Karsten, and
the ductility is restored only by heating to a red heat and
suddenly cooling. Mushet finds that the alloy, copper 97,
tin 2, makes good sheathing, as it is not readily dissolved in
hydrochloric acid. The best gun-metal is from copper 90,
tin 10, to copper 91, tin 9 ; if richer in copper, it is especially
liable to liquation, which action is detrimental to all these
alloys. Bell-metal, copper 80, tin 20, to copper 84, tin 16, is
sonorous and makes good castings, but is hard, difficult to
* Dingier1 s Journal, Ixxxv., p. 378 ; Watts's Diet, ii., p. 43.
AND OTHER COfPER-TIN ALLOYS. I3/
work and quite brittle. Suddenly cooling it from a high
temperature reduces its brittleness, while slow cooling re-
stores its hardness and brittleness. It is malleable at low
red heat and can be forged by careful management.
Speculum-metal, copper 75, tin 25, is harder, whiter, more
brittle and more troublesome to work than bell-metal.
Old flexible bronzes contain about ^ ounce of tin to the
pound of copper, or copper 95, tin 5, as stated by Ure.
Ancient tools and weapons, as shown elsewhere, contain
from 8 to 15 per cent, tin ; medals from 8 to 12 per cent., with
often 2 per cent, zinc to give a better color. Mirrors con-
tained from 20 to 30 per cent. tin. The metals mix in all
proportions, and the alloys are, to a certain extent, independ-
ent of their chemical proportionality. The occurrence of
hard, brittle, elastic alloys between the extremes of a series
having soft tin and ductile copper at either end, both of
which metals are inelastic, is probably a proof that these
alloys are sometimes chemical compounds. They are proba-
bly, usually, compounds in which are dissolved an excess of
one or the others of the components.
76. The Principal Bronzes are those used in coinage, in
ordnance, in statuary, in bells, and musical instruments, and
in mirrors and the specula of telescopes. These alloys oxid-
ize less rapidly than copper, are all harder, and often stronger
and denser.
Coin bronze, as made by the Greeks and Romans, con-
tained from copper 96, tin 4, to copper 98, tin 2, and Chaudet has
shown that the first of these alloys can be used for fine work,
obtaining medals of this composition of very perfect polish
while sufficiently hard to wear well. Puymaurin succeeded
well with alloys of copper 93.5, tin 6.5, to copper 90, tin 10;
and Dumas found the range of good alloys for this purpose
quite large, varying from 96 copper, 4 tin, to 86 copper, 14 tin,
but the best falling near the middle of this range.
Gun bronze has various compositions in different countries.
The most common proportion would seem to be copper 90,
tin 10, or copper 89, tin II. Well made, it is solid, yellowish,
denser than the mean of its constituents, and much harder
138 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
stronger, and more fusible than commercial copper; it is
somewhat malleable when hot, much less so when cold.
It is subject to some liquation, and should therefore be
quickly chilled in the mould ; it loses some tin when per-
mitted to stand at a temperature of 400° to 500° Fahr. (200°
to 260° C.). This liquation gives rise to light-colored spots
throughout the metal. This bronze does not readily oxidize
at ordinary temperatures, but is quickly attacked when hot ;
it usually becomes greenish when exposed to the weather, by
the formation of the hydrated carbonate; thus "patina" is
observed on all unpolished old bronze guns or old statues.
Statuary bronze is usually of nearly the same composition
as gun-bronze. It should be rapidly melted, poured at high
temperature, and quickly cooled to prevent liquation.
Bell-metal is richer in tin than the preceding, and varies
in composition somewhat with the size of bell. The propor-
tion, 77 copper, 23 tin, is said to be a good one for large bells ;
it shrinks 0.015 in the mould while solidifying. The range
of good practice is found to be from 1 8 to 30 per cent, tin, 82
to 70 per cent, copper; the largest proportions of tin are used
for the smallest bells, and an excess is added to meet the
liability to oxidation and liquation; copper 78-82, tin
22-18, is a very usual composition. When made of scrap
metal, as is not uncommon, serious loss of quality is liable to
occur by the introduction of lead and other metals deficient in
sonorousness. When properly made, this alloy is dense and
homogeneous, fine-grained, malleable if quickly cooled in the
mould, rather more fusible than gun-bronze, but otherwise quite
similar; excelling, however, in hardness, elasticity and sonority.
These bronzes become quite malleable when tempered
by sudden cooling, and this treatment is resorted to when
they are to be subjected to prolonged working or to a
succession of processes. Chinese gongs are made of copper
78 to 80, tin 22 to 20, and are beaten into shape with the
hammer, the metal being softened at frequent intervals by
heating to a low red heat and plunging into cold water. The
tone desired is obtained by hammering the instrument until
the proper degree of hardness is obtained. Tempering not
BRONZES AND OTHER COPPER-TIN ALLOYS. 139
only increases the ductility and malleability of these alloys,
but also, it is claimed, their strength, while decreasing their
hardness and density, when they are made into thin sheets;
thick plates are less affected ; annealing by slow cooling pro
duces an opposite effect.
Speculum-metal contains, often, as much as 33 per cent,
tin ; it is steely, almost silvery white, extremely hard and
brittle, and capable of taking a very perfect polish. The most
suitable proportion of tin varies slightly with the character of
the copper, some kinds requiring more and some less to give
the degree of whiteness and the perfection of polish required.
An excess of tin injures the color and reduces the lustre of
the mirror.
The finest speculum metal is perfectly white, without a
shade of yellow, sound, uniform, and tough enough to bear
the grinding and polishing without danger of disintegration.
The specula made by Mudge were twice fused, and con-
tained from 32 parts copper and 16 tin to 32 copper and 14.5
tin. A little tin is lost in fusion. According to David Ross,
the best proportions are: copper, 126.4; tin, 58.9, i.e., atomic
proportions. He adds the molten tin to the fused copper
at the lowest safe temperature, stirring carefully, and secur-
ing a uniform alloy by remelting, as is often done in making
ordnance bronze.
Bronze for bearings and pieces subject to severe friction,
as in machinery, is made of many proportions. Gun-bronze
is one of the best ; the Author has known of one case in
which the bronze was made of ingot copper 90, ingot tin 10,
and used in the main crank-shaft journal of a steam vessel for
ten years without appreciable wear, although the area was not
unusually large for the load and the velocity of rubbing was
high, as is usual in screw engines. The proportions given in
several cases will be found elsewhere ; they vary in practice
from 88 to 96 per cent, copper, as more or less hardness is
required. Bronze for steam engine packing rings is some-
times made of 92 to 94 copper, 7 to 9 parts tin, I part zinc.
77. Old Bronze. — According to Riche,* the analysis of
* Appendix to U. S. Report on Tests of Iron and Steel, vol. i, p. 556.
140 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
antique medals shows that, though the ancients sometimes
used copper for this purpose, they ordinarily employed bronze
in which the proportion of tin varied between wide limits
(from 1 to 25 per cent.). The manufacture of medals with a
bronze rich in tin is not practised at the present day, on
account of its hardness, and because considerable relief is
necessary, while this was very slight in the medals of antiquity.
Bronze has been wholly given up and copper substituted for
it ; but copper also presents some serious inconveniences.
It rusts badly, does not ring when struck; its red tint is not
artistic, and this is concealed by an artificial bronzing which
adheres poorly, and which causes different medals to vary in
tone.
In 1828, M. dePuymaurin made a large number of experi-
ments, and continued them until 1832, after which an alloy of
94 copper, 4 tin, and 2 zinc was adopted in France, of which,
from time to time, medals were manufactured until 1847, at
which time it was entirely given up on account of the hard-
ness of the metal leading to a deterioration of the coin.
Riche advises a bronze containing 96 or 97 per cent, copper,
and 4 or 3 per cent, tin, as less hard, more sonorous, capable
of making good castings, and of working well in the rolls,
under the hammer, or in the dies ; it has also a good color.
78. Oriental Bronzes. — Analyses of Japanese bronzes,
made by M. E. J. Maumene,* give the following:
NO. I.
NO. 2.
NO. 3.
NO. 4.
Copper .
86.38
SO.QI
88.70
92.07
Tin
I.Q4
7-55
2.58
1.04
Antimony
1.61
0.44
O.IO
I.O4
Lead
5.68
5.33
3-54
1.04
Zinc
3 «V
3.36
3.08
3.71
2.65
Iron . .
o 67
1.43
1.07
3.64
0.67
trace
i. 07
3.64
Silicic acid . . .
O. IO
o. 16
0.09
O.O4
O. IO
0.31
0.09
O.O4
Waste
o 26
o. 70
O.2I
0.56
IOO.OO
100.00
100.00
IOO.OO
* Comptes Rendus, 1875.
BRONZES AND OTHER COPPER-TIN ALLOYS.
141
These alloys are all of a granulated texture, blistered on
the interior surface, sound on the exterior surface (which can
be readily polished with a file). Their color is sensibly violet
when antimony is abundant, red when iron is present. All
the specimens were cast thin, from 0.195 to 0.468 inch, and
the mould was well filled. It appears by analysis that these
alloys were not made with pure metals, but with minerals.
We should, says Maumene, consider these bronzes as result-
ing from the use of copper pyrites, and antimonial galena
mixed with blende ; and the calcination was not always com-
plete, as the presence of sulphur in specimen No. 2 proves.
Antique alloys, Greek, Roman, old French, etc., present
similar indications.
79. Density of Bronzes. — The increase of density above
the mean of the densities of the two constituents, probably
either due to the affinity of the metals, or freedom from air-
cells, is exhibited by the following table, prepared by Briche :
ALLOY.
S. G. ACTUAL.
CALCULATED.
DIFF.
Cop
>per i
oo; t
in 4
8.79
8.78
8.76
8.76
8.80
8.81
8.87
8.83
8.79
8.74
8.7I
8.68
8.66
8.63
8.61
8.60
8.43
8.05
0.05
0.07
0.08
0.10
0.17
0.20
0.27
0.40
0.74
6
8
TO
12
16
•5-J
100
The condensation of the alloy, due to the affinity of its con-
stituents, or to greater homogeneousness, increases as the pro-
portion of tin increases throughout the range above studied.
80. Ordnance Bronze.— According to the U. S. Ordnance
Manual, bronze used for ordnance consists of 90 parts of
copper and 10 of tin, allowing a variation of one part of tin,
more or less. It is more fusible than copper, much less so
than tin, more sonorous, harder, and less susceptible of oxida-
tion, and much less ductile, than either of its components.
When the mixture is well made, the metal is homogeneous;
142 MATERIALS OF ENGINEERTNG— NON-FERROUS METALS.
the fracture is of a uniform yellow color, with an even grain.
The specific gravity of bronze is about 8.7, being greater
than the mean of the specific gravities of copper and tin.
Copper proposed to be used in ordnance bronze should
be condemned for the manufacture of guns, if it contains
sulphur in an appreciable quantity ; more than one-thou-
sandth of arsenic and antimony united ; more than about
three-thousandths of lead, iron, or oxygen ; if it contain more
than about five-thousandths of foreign substances altogether ;
or if, near these limits, it give bad results when subjected to
the mechanical tests of hammering, rolling, and wire-drawing.
It is also stated that tin offered should be rejected if,
when run into elongated drops, it have not a smooth and re-
flecting surface, without any considerable sign of rough spots ;
if, when analyzed, it contain more than about one-thousandth
of arsenic and antimony united ; more than about three-
thousandths of lead or iron ; or more than four-thousandths
of foreign substances.
All bronze ought to be rejected which contains sulphur in
an appreciable amount; which contains more than about one-
thousandth of arsenic and antimony united; more than
about three-thousandths of lead, iron, or zinc; or, in all,
more than about five-thousandths of foreign substances.
Notice should be taken of the appearance of the fracture
of specimens ; it sometimes gives indications sufficient to
authorize the rejection of certain bronzes full of sulphur or
oxides.
Gun-metal, when broken, should present a fine, close-
grained fracture, of a uniform, beautiful golden color; it should
be ductile, although finely granular and possibly crystalline.
Bronze guns often exhibit, when burst, a decidedly crystal-
line surface, the axes of the crystals lying radially to the bore.
According to the practice of the Navy Department, the
bronze used for rifled howitzers is composed of Lake Superior
copper 9 parts, tin I part. This is used when the casting
is made in a sand mould. When a chill mould is used, which
is the method now adopted for such castings, the proportion
is changed to 10 to I.
BRONZES AND OTHER COPPER-TIN ALLOYS.
The copper is melted in a reverberatory furnace, and
three hours after the fires are started, when the copper is in
perfect fusion, the tin is stirred in ; half-an-hour after, the
bronze is run off into the moulds. The casting cools nat-
urally, and is taken out of the mould about twenty-four hours
after the metal is run in. The chill mould is warmed suf-
ficiently to drive out the moisture.
81. Phosphor-Bronze and Manganese Bronzes are alloys
which are now so well known and have become so important
in the arts as to demand special notice.
Phosphor bronze has been known many years. It consists
simply of any alloy of bronze or brass or any ternary alloy of
copper, tin and zinc which has been given exceptional purity
and excellence by skilful fluxing with phosphorus. It is also
supposed that the presence of phosphorus is useful in giving
the tin a crystalline character which enables it to alloy itself
more completely and strongly with the copper. Phosphor-
bronze will bear remelting with less injury than will common
bronze. The phosphor bronzes greatly excel the unphos-
phuretted alloy in every valuable commercial quality, and
they are very extensively used for every purpose for which
such alloys are fitted.
The following are Kirkaldy's figures for tenacity and
ductility of phosphor-bronze wire of No. 16 Birmingham
gauge :
PHOSPHOR-BRONZE WIRE, NO. 1 6, B. W. G.
MATERIALS.
LOAD AT FRACTURE.
o "*
SJJ
No. twists be-
C be
fore breaking.
Unannealed.
Annealed.
,2 c
Per sq.
mm.
Per sq .
in.
Per sq.
mm.
Per sq.
in.
Per
cent.
Unan-
nealed.
An-
nealed
r
72.3 kil.
46 T.
34. 7 kil.
22 T.
37-5
6-7
80
Phosphor-bronze
of several pro- -I
portions.
85.1
85.2
97-7
112. 2
54
54-1
62.1
71 2
33-6
37-5
42.8
41.7
21.3
23.8
27.2
26.5
34-1
42.4
44-9
46.6
22.3
13.0
17-3
13-3
52
124
53
66
I
106.3
67.6
45-4
28.9
42.8
15-0
60
144 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
CAST PHOSPHOR-BRONZE.
REDUCT. OF SEC-
TION.
ELASTIC LIMIT.
ULTIMATE RESISTANCE.
Per cent.
Per. sq. mm.
Per sq. in.
Per sq. mm.
Per sq. in.
8.4
i-5
33-4
16.05 kil.
17-38
II. 6
10.6 T.
11.05
7.2
37-0
32-5
31-3
23- 5 T.
20.6
19.9
The phosphorus is sometimes added to the alloy in the
form of copper-phosphide, which is made by reducing acid
phosphate with charcoal. This is added to the extent of
from one and a half to three and a half per cent. Dry phos-
phorus may be added in the crucible if preferred to phos-
phor-tin or copper-phosphide.
Phosphor-bronze was early known to chemists, but its
valuable qualities as a material to be used in construction
were first made known by MJVf. Montefiori, Levi, and Kun-
zel, who discovered the alloy in the year 1871. According to
Dick,* who introduced the alloy into the United States, the
chemical action of phosphorus on the metals composing the
alloy is two-fold : it reduces any oxides dissolved therein,
and it forms with the purified metals a homogeneous and
regular alloy, the hardness and the toughness of which are
completely under control.
We summarize, from the same source, the special uses of
phosphor-bronze : I. It is very tough, and thus fitted for pis-
ton rings and valve covers. 2. It is very tough and hard, and
therefore used for machine castings, pinions, cog-wheels, pro-
peller screws, hydraulic press and pump barrels, piston rods,
screw bolts for steam cylinders, and hardware. 3. Very hard
bronze is adopted for bearings of heated rolls, valves, etc.
4. Harder and stronger alloys than ordinary bell metal are
employed for bells, steam-whistles, etc. 5. Acquiring great
toughness, elasticity, and strength under the hammer, it is
* Journal Franklin Institute, 1878.
BRONZES AND OTHER COPPER-TIN ALLOYS. 145
used for hammered piston-rods and bolts. 6. As bearing
metal it is said to be better than the best gun-metal, very
much less liable to heat than gun-metal, and when heated, it
does not cut the journal.
Ordnance has been made of this modification of gun-
bronze by European nations, and has been found to excel in
strength, toughness, and endurance. Small arms have also
been made of it, and, in ship-work, the screws and sometimes
rods in small vessels. When sheathing of this metal is used,
it is found to possess exceptional power of resisting corro-
sion.
82. Uses of Phosphor-Bronze. — The comparatively high
cost of phosphor-bronze has checked its introduction, not-
withstanding its undeniable excellence. It is said to be
stable, not losing much phosphorus by remelting, the tempera-
ture of the fusion of the alloy being kept low, ranging from
752° to 932° Fahr. (400° to 500° C).
Phosphor-tin is now sold in the market for use in making
this bronze ; it is known by its number, as No. o, No. I.
All alloys made with copper and phosphor-tin may be
forged cold, provided the percentage of tin does not much
exceed 12 per cent., and by this treatment they increase con-
siderably in hardness. An alloy of 94 or 95 per cent, of cop-
per, and 6 or 5 per cent, of phosphor-tin, may attain the hard-
ness of ordnance steel, while the toughness of the bronze
remains high. When expense does not permit the use of
phosphor-bronze instead of ordinary bronze, the quality of
the latter may be very materially improved by re-placing
one-tenth of the percentage of tin by phosphor-tin, which
carries enough phosphorus into the bronze to deoxidize the
metals in the alloy, and the small increase in cost is coun-
^terbalanced by soundness of castings and improved working.
It is best to avoid the use of zinc in making phosphor-
bronze with phosphor-tin. Take, for heavy main-shaft jour-
nals, 85 per cent, of copper and 15 per cent, of phosphor-tin,
and for coupling and crank- rod journals, 90 per cent, of cop-
per and 10 per cent, of phosphor-tin ; these alloys have great
hardness and high tensile strength and toughness*
MATERIALS OF ENGINEERING— NON-FERROUS METAL&
As a substitute for ordinary bronze take :
r (35 parts of zinc,
30 parts of good brass \ ~.
( 65 parts of copper,
16 parts of copper,
4 parts of phosphor-tin, No. O.
Gearing, tuyeres for blast-furnaces, and wire ropes of this
alloy have been successfully used, the latter on the hoists of
deep mines in Europe ; they have the advantages of great
strength and freedom from corrosion.
Phosphide of copper may be used in the manufacture of
phosphor-bronze. It may be prepared by adding phosphorus
to copper sulphide solution and boiling, adding sulphur as
the sulphide is precipitated. The precipitate is carefully
dried, melted, and cast into ingots. When of good quality
and in proper condition, it is quite black.
Phosphide of tin is oftener employed. When the precipi-
tated tin obtained by the addition of zinc to a solution of
chloride of tin (SnCl2) is heated with phosphorus in the pro-
portions of about nine atoms of tin to one of phosphorus, the
phosphide (Sn9P) is produced. This compound resembles
cast zinc, is crystalline, melts at about 370° C. (700° F.) and
can be easily introduced into the crucible in the process of
manufacture of bronze.
" Phosphor-bronze " is, therefore, any copper-tin alloy or
bronze which has been fluxed, in the process of making the
alloy, by the addition of a measurable quantity of phosphorus.
The metalloid may be added either pure or combined, and
either to the alloy itself or to one of its constituents, usually
to the tin — often as phosphate of copper, before mixing. A
small quantity of phosphorus, chemically uniting with copper,
hardens and strengthens it. Added in the process of manu-
facture, in larger amount, it prevents the formation of copper,
or other metal, oxide, and thus produces an alloy of such purity
as to give greatly increased strength, and ductility as well,
and also greater homogeneousness.
In using phosphate of copper, Messrs. Ruoltz and de Fon-
tenay mix the sirupy acid phosphate with 0.20 charcoal and
BRONZES AND OTHER COPPER- TIN ALLOYS. l$]
melt in plumbago crucibles, and use this material in the fol-
lowing proportions,* the phosphate containing 9 per cent,
phosphorus :
In preparing phosphor-bronze it seems immaterial whether
phosphor-copper or phosphor-tin is used, though the former
is more likely to find an extended use, as it is applicable, not
only for phosphor-bronze, but for other copper alloys contain-
ing no tin, as yellow brass, German silver, etc., and for pure
copper. It also possesses the advantage of being able to
take up the greatest quantity of phosphorus, and consequently
to offer the efficient reagent in the most compact form.
In making phosphor-bronze or copper alloys of all sorts,
the copper should first be melted in the usual way, with a
cover of charcoal put over it as quickly as possible. After
the required quantities of tin, zinc, etc., have been added,
or in case of gun metal or brass scrap, after the latter has
been completely melted, the small exactly weighed quantity
of phosphor-copper is added while the metal is continually
stirred. For stirring, a graphite bar, a strip cut from an old
plumbago crucible, or a bar of retort carbon should be used.
The stirring has to be done carefully, and the metal then
freed of the coal and scoriae floating on the top ; it should be
poured before the surface begins to be covered with a skin.
The latter point and the careful stirring cannot be too
urgently recommended. Phosphor-metals should always be
covered with charcoal when remelted. A further addition of
an extremely small quantity of phosphor-copper is necessary
only in case the metal should not assume a bright mirror
face. Phosphor-tin is better than phosphor-copper.
For preparing phosphor-bronze or remelting old gun metal
and turnings, the addition of ij^ Ib. to i^ lb. of phosphor-
copper of 15 per cent, phosphorus is generally sufficient fora
hundred-weight of metal. In making or remelting brass,
an addition of J^ to ^ part only is required per hundred.
A larger percentage increases the hardness, but may lead
to brittleness. The phosphor-copper of 15 per cent, phos-
phorus itself is so brittle that the small ingots of about 2 lb.
* Lebasteur, p. 321.
148 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
(i kg.) weight in which it is usually sold, can be broken in the
hand by a light blow with a hammer into such pieces as are
required.
Sheathing metal made of phosphor-bronze is found to
resist the action of sea-water remarkably well. In experi-
ments made at Blankenbergh, lasting six months, comparing
the best English copper and phosphor-bronze, the following
results were arrived at : *
LOSS OF
THICKNESS OF THE SHEETS
WEIGHT BE- WEIGHT
WEIGHT.
= 0.236 in.
FORE IMMER- AFTF.R TM-
= 0.6 cm.
SION.
MERSION.
Actual.
Per
cent.
74-4
72.2
2.2
3OIS
Do.
88 Q
86 2
27
3 loo
Sheet of phosphor-bronze ....
69.5
68.75
0.75
1.123
Do. Do
U4-3
112.97
1-33
I-I95
The loss in weight, therefore, due to the oxidizing action
of sea-water during the six months' trial, averaged for the
English copper 3.058 per cent., while that of the phosphor-
bronze was but 1.158 per cent.
According to Delalot,f true phosphor-bronze is not an
alloy ; it is a combination of copper with phosphorus ; it is
simply a phosphide of copper in definite proportions. The
metal unites with the metalloid either cold or hot ; for some
applications of phosphor-bronze the cold method suffices.
Phosphor-bronze made by the hot process does not allow the
introduction of simple bodies other than the metal and the
metalloid. Copper exempt from arsenic, antimony, iron, or
zinc, is required ; it must be commercially pure. The manu-
facturer may choose from three kinds of phosphorus, ordinary,
amorphous, and all the earthy biphosphates. Amorphous
phosphorus is the most expensive, but the best. The secret
of making good phosphor-bronze lies in the working of the
* M. J. Maure, Engineering, Sect. T2 ; 1873.
f Moniteur Industrielle Beige ; 1878.
BRONZES AND OTHER COPPER-TIN ALLO YS. 149
furnace and in practice. The following are the best combina-
tions in definite proportions. The minimum and maximum
percentages of phosphorus in phosphor-bronze are 2 and 4.
Five sorts of phosphor-bronze, however, are considered to
answer all requirements.
0. Ordinary phosphor-bronze of 2 per cent, of phosphorus.
1. Good " " " 2% " "
These two numbers are superior to ordinary bronze and
steel in all cases.
2. Superior phosphor-bronze of 3 per cent, of phosphorus.
3. Extra " " " 3^
4. Maximum " " " 4 "
These three, according to Delalot, are superior to any
other bronzes. Above No. 4, phosphor-bronze is useless ;
below o, it is inferior to common bronze and steel. The
price of phosphor-bronze un worked, for all numbers, should
not exceed that of copper by over ten per cent. Nos. 3 and 4
are comparatively unoxidizable.
It is stated by Dumas that the characteristics of these alloys
change with the addition of phosphorus. The color, when
the proportion of phosphorus exceeds y£ per cent, becomes
warmer, and like that of gold largely alloyed with copper.
The grain and fracture approximate to those of steel. The
elasticity is considerably increased, the tenacity also becomes
in some cases more than doubled ; the density is also in-
creased, and to such a degree that some phosphor-bronzes
are with difficulty touched by the file. The metal, when
cast, has great fluidity, and fills the mould perfectly, exhibit-
ing the smallest details. By varying the doses of phosphorus
and tin, the particular characteristic of the alloy which is
most desired can be varied at pleasure.
83. Tabular Exhibit of Properties of the Copper-Tin
Alloys.* — The following table is a list of about 140 different
alloys of copper and tin, giving some of their mechanical and
physical properties.
* Prepared originally for the U. S. Board ; Committee on Alloys' Report,
vol. i , 1878, p. 389.
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In the above table the figures or order of ductility, malle-
ability, hardness, and fusibility are taken from Mallet's experi-
ments on a series of sixteen alloys, the figure I representing
the maximum and 16 the minimum of the property. The
ductility of the brittle metals is represented by Mallet as o.
The relative ductility given in the table of the alloys ex-
perimented on by the U. S. Board, is the proportionate exten-
sion of the exterior fibres of the pieces tested by torsion as
determined by the autographic strain-diagrams. It will be
seen that the order of ductility differs widely from that given
by Mallet.
The figures of relative hardness, on the authority of Cal-
vert and Johnson, are those obtained by them by means of an
indenting tool. The figures are on a scale in which cast iron
is rated at 1,000. The word " broke " in this column indi-
cates the fact that the alloy opposite which it occurs broke
under the indenting tool, showing that the relative hardness
could not be measured, but was considerably greater than
that of cast iron. The quality of the iron is not specified.
The figures of specific gravity show a fair agreement
among the several authorities for the alloys containing more
than 35 per cent, of tin, except those given by Mallet, which
are in general very much lower than those by all the other
authorities. In the alloys containing less than 35 per cent,
of tin there is a wide variation among all the different authori-
ties ; Mallet's figures, however, being generally lower than the
others. Several of the figures of specific gravity have been
selected from Riche's results of experiments on the effects of
annealing, tempering, and compression, which show that the
latter especially tends to increase the specific gravity of all
the alloys containing less than 20 per cent, tin to about 8.92.
This result, as stated in the discussion on specific gravity
above, is due merely to the closing up of the blow-holes,
and thus diminishing the porosity. The specific gravity of
8.953 was obtained by Major Wade by casting a small bar in
a cold iron mould from the same metal which gave a specific
gravity of only 8.313 when cast in the form of a small bar in a
clay mould. The former result is exceptionally high, and in-
BRONZES AND OTHER COPPER-TIN ALLOYS.
dicates the probability that every circumstance of the melt-
ing, pouring, casting, and cooling was favorable to the ex-
clusion of the gas which forms blow-holes, and to the forma-
tion of a perfectly compact metal.
The figures of tenacity given by Mallet, Muschenbroek,
and Wade agree with those found in the experiments de-
scribed in this volume as closely as could be expected from
the very variable strengths of alloys of the same composition
which have been found by all experimenters.
Mallet's figure for copper, 24.6 tons, or 55,104 pounds, is
probably much too high for cast copper; the piece which he
tested was probably rolled or perhaps drawn into wire. Has-
well's Pocket Book gives the following as the tensile strength
of copper; the names of the authorities are not given :
Pounds per
square inch.
Copper, wrought 34,000
Copper, rolled 36,000
Copper, cast (American) 24,250
Copper, wire 61, 200
Copper, bolt 36,800
This table of comparison of authorities is by no means
complete. No account is taken of a vast number of ancient
bronzes, weapons, medals, coins, and sonorous instruments
which have been described by various writers. These, how-
ever, differ but little in composition and properties from the
ordnance and bell metal given in the tables.
It will be observed that while there is considerable irregu-
larity in the tenacity of the alloys containing more than 27.5
per cent, of tin, they are all extremely weak, the highest
strength found by any experimenter being only 8,736 pounds,
and valueless for all purposes in which strength is required.
It has been shown that the useful alloys, those which con-
tain less than 27.5 per cent, of tin, have strengths which are
nearly proportional to their densities.
CHAPTER V.
THE BRASSES AND OTHER COPPER-ZINC ALLOYS.
84. Brass is a term which is applied by many, and espe-
cially older, authors indifferently to all alloys composed princi-
pally of copper, combined with either tin or zinc. The alloy
of copper and tin and its minor modifications are now becom-
ing better known as bronze, and the name brass is generally
restricted to the designation of alloys consisting mainly
of copper and zinc. " Brass " ordnance is properly called
bronze ordnance, and the compositions used in the bearings of
machinery, which are usually of somewhat similar compo-
sition, are also properly called bronzes. The alloys of copper,
tin and zinc, which occupy intermediate positions between
the bronzes and the brasses, are as often known by the one
name as by the other.
85. Copper and Zinc together form " Brass," which is usu-
ally made nearly in the proportion, copper, 66j^, zinc 33^.
Brasses of certain other proportions have specific names, as
Tourbac, Pinchbeck. The mixture and fusion of the metals
must be so conducted that the loss of zinc by volatilization
may be the least possible ; there is always some loss, and it
may not only be serious as a matter of cost, but the introduc-
tion of oxides into the alloy is exceedingly injurious to its
quality. The fusion is generally performed in crucibles heated
in air-furnaces.
The change of color and of other qualities with the intro-
duction of zinc is gradual and very similar in character to
that produced by the admixture of tin ; but the quantity of
zinc demanded to produce the same modification is about
twice as much as of tin. On adding zinc, the deep red color
of copper is changed at once, becoming lighter and lighter,
BRASSES AND OTHER COPPER-ZINC ALLOYS.
159
and finally shading into a grayish white and then assuming
more of the color of zinc. The alloy generally increases in
hardness and loses ductility as the percentage of zinc is in-
creased, up to a maximum, which being passed, ductility
increases again. The most ductile are, however, those which
contain 70 to 85 per cent, copper, 30 to 15 of zinc, the first
being called "tombac," the latter "brass."
86. Mallet's Classification.— The following is Mallet's
table of the copper-zinc alloys :
TABLE XXI.
PROPERTIES OF COPPER-ZINC ALLOYS.
AT. COMP.
COPPER
S. G.
COLOR.
FRACT.
TENACITY.
ORDER OF
Mall.
Hard.
Fus.
by anal.
Cu Zn
per ct.
Tons per sq. in.
I
100.
8.667
red
...*-•-- . .
24.6
8
22
15
IO
98.80
8.605
red-yellow
coarse
12. 1
6
21
14
9
90.72
8.607
4
fine
II.5
4
20
'3
8
88.60
8.633
t
it
12.8
2
19
12
1
87.30
85.40
8.587
8.591
yellow-red
Ci
fine-fibre
13-2
II.I
0
5
18
II
IO
S
4
3
2
83.02
79-65
74-58
66.18
8.415
8.448
8-397
8.299
pale yellow
deep '
ii
13-7
14-7
12-5
IT
7
IO
3
\76
IS
14
23
I
I
49-47
8.230
U 41
coarse
9.2
12
12
6
I
32.85
8.263
dark "
i4
19-3
I
10
6
8 17
8 18
31-52
30.36
silver white
silver white
tt
u
2.1
2.2
very brittle
i
5
5
8 19
8 20
29.17
28.12
7.019
7.603
light gray
ash "
it
vitreous
0.7
3-2
ti
brittle
7
3
5
5
8 21
27.10
8.058
light "
coarse
11
9
5
8 22
26.24
7.882
U U
4i
0.8
"
i
5
8 23
1 3
25-39
24.50
7-443
7-449
ash "
U Ci
fine
5-9
3-1
slight duct,
brittle
i
2
5
4
1 4
19.65
7-371
it «
**
. i-9
"
4
3
i 5
O I
16.36
o.
6.605
dark "
it
1.8
15.2
ii
23
2
I
• 95
In the above table, the minimum of hardness and fusibility is denoted by i.
The conclusion of Storer*that these alloys are mixtures
rather than true compounds, is accepted by Watts and other
authorities.
87. Uses of Brass. — Brass is the alloy commonly em-
ployed in the arts in the construction of scientific apparatus,
* Mem. Am. Acad., N. S., vol. viii, p. 97.
100 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
mathematical instruments, and small parts of machinery. It
is cast into parts of irregular shape, drawn into wire, or rolled
into rods and sheets. It is harder than copper, very malle-
able and ductile, and can be ** struck up " in dies, formed in
moulds, or " spun " into vessels of a wide variety of forms if
handled cold or slightly warm ; it is brittle at a high tempera-
ture. A common proportion for making brass is copper 66,
zinc 34. This alloy is a much slower conductor of electricity
and of heat than copper, is more fusible, oxidizes very slowly
at low temperatures, but rapidly at a high heat.
The brass of Rom illy, which works remarkably well under
the hammer, is composed of copper 70, zinc 30 ; English
brass is often given 33 per cent, zinc, and for rolled brass 40
per cent. This constitutes "Muntz sheathing metal," as
patented by G. F. Muntz in 1832. The proportion of zinc
ranges, however, for such purposes, from 37 to 50 per cent,
copper 63 to 50.
88. Muntz Metal is thus described by its inventor : —
" I take that quality of copper known in the trade by the ap-
pellation of ' best selected copper/ and that quality of zinc,
known in England as ' foreign zinc/ and melt them together
in the usual manner in any proportion between 50 per cent,
of copper to 50 per cent, of zinc, and 63 per cent, of copper
to 37 per cent, of zinc, both of which extremes, and all
intermediate proportions, will roll and work at a red heat ;
but as too large a proportion of copper increases the diffi-
culty of working the metal, and too large a proportion of
zinc renders the metal too hard when cold, I prefer the
alloy to consist of about 60 per cent, of copper to 40 per
cent, of zinc. This compound I cast into ingots of any con-
venient weight, and then heat them to a red heat, and roll or
work them while at that heat into bolts and other like ship'$
fastenings, in the same manner as copper is rolled or worked/,
but only taking care not to overheat the metal so as to pro-,
duce fusion, and not to put it through the rolls or work it
after the heat has left it too much, say, when the red heat<
goes off."
This alloy is cast into ingots, and rolled, hot, into sheets,
BRASSES AND OTHER COPPER-ZINC ALLOYS. l6l
which are cleaned by pickling and washed before they are
sent into the market. As this alloy is cheaper and more du-
rable than copper sheathing, and equally effective, it has dis-
placed the latter almost entirely in the protection of wooden
ships. When made on a large scale, the alloy is melted in a
reverberatory furnace.
89. Special Properties. — Farmer has deposited brass by
electrolysis and obtained an alloy containing copper 75, zinc
25, as ductile and malleable as rolled brass.
The brasses, or copper-zinc alloys, although probably of
more extended use than the bronzes or copper-tin alloys, are
not as well studied as the latter.
The metals, as already stated (§ 85), mix in all propor-
tions, and produce alloys of which the general character has
been shown in the introductory chapter of this part of the
work and in the earlier paragraphs of this chapter.
The red color of copper, in this series, fades into yellow
very gradually, and becomes golden-yellow at about 40 per
cent, zinc ; the color then becomes lighter, and at 60 per
cent, zinc is bluish-white or silvery. With the change of
color occurs the same change of strength and ductility noted
with the copper-tin alloys, but it requires about twice as
much zinc as tin to produce it. The white metals richest in
copper are, like those of the bronze class, too brittle to be of
use in engineering construction, but the yellow metals ob-
tained with from 40 to 50 per cent, zinc are very valuable.
Brass has a high coefficient of expansion, 0.000054 to
0.000056 per Cent, degree (0.00003 to 0.000033 Per degree
F.).* Yellow brass fuses at from 1,870° F. (1,021° C), and
other compositions from 1,000° F. (550° C., nearly) to 2,000° F.
(1,100° C., nearly), and loses strength and ductility as its tem-
perature rises. The composition of the several most useful
brasses is given elsewhere. Brass for fine work is often made
of copper, 80; zinc, 17; tin, 3 ; "fine brass" of 2 copper, I
of zinc ; sheet brass of 3 copper, I zinc. A hard solder is
made of 3 parts brass to I of zinc, etc., etc. Castings shrink
in cooling T\ inch to the foot (0.015).
* Vide Chapter I.
n
1 62 MATERIALS OF ENGINEERING— NON-FERROUS METALS
Hydrochloric acid reddens brass by dissolving its zinc;
ammonia whitens it by taking up the copper.
Brass may be made tough and soft, hard and brittle, strong
or weak, elastic or inelastic, dull of surface or lustrous as
a mirror, friable or nearly as mal'eable and ductile as lead, as
may be desired, by varying its composition. No known ma-
terial, perhaps not even excepting iron, can be given so wide
a range of quality or so wonderful a variety of uses. All the
common varieties are composed of 67 to 70 parts copper and
33 to 30 of zinc. A little lead is often added to soften and
cheapen it and tin in small proportion to strengthen it.
Brass is subject to flow under stress, like all other metals
of what the Author has called the " tin class," and it is not
safe to leave heavy loads upon it. Weights should not usually
be hung upon brass chains, or upon brass tie-rods. The alloy
is capable of being considerably hardened by compression, as
when rolled into sheets, or by wire-drawing, and becomes
much stronger and is less liable to permanent change under
load. Some compositions are very elastic and make good
springs for intermittent and occasional use.
The thin sheet brass used for metallic cartridges and
other purposes requiring a metal in this form of great strength
combined with ductility, is subject, frequently, to a singular
deterioration with age which seem to be partly a physical and
partly a chemical change. It results, sometimes in a very
brief interval, in the entire destruction of the essential proper-
ties of such forms of this alloy. This has been studied by
Egleston,but the results of irvestigation are not yet fully
known.
Weems has found * that a pressure of 4,000 tons (or ton-
nes) being applied to brass, in the endeavor to produce brass
tubes by " squirting " as is usual with lead, causes a separa-
tion of the zinc, which issues as a zinc pipe, leaving the cop-
per behind. This is considered a proof that this alloy is a
mixture rather than a chemical compound.
90. Applications in the Arts. — Bronze and brass have in-
numerable uses in the arts : locks, keys, shields, escutcheons,
* Lond. Engineer > 1883.
BRA SSES A ND 0 THER COPPER-ZINC ALLO VS. 1 63
hinges, journal-bearings, pump-plungers, screw propellers, all
small parts of machinery, optical and other philosophical
instruments, cabinet-makers' fittings, sheathing of ships. Even
so-called copper castings usually contain a small amount of
zinc — 2 to 5 per cent., to give them soundness.
The copper and brass manufactures of the United States
are very extensive and of excellent character, both as to ma-
terial and workmanship, and in those departments which are
purely mechanical, are probably unequalled elsewhere. The
purest copper is at their doors and the best of zinc ; while
tin is likely, in time, to be largely produced in this country
also.
Brass to be used in the rolling mill in the manufacture of
sheet metal, is cast between marble blocks which are separ-
ated to a distance which determines the thickness of the
ingot or slab. The marble is coated with a thin layer of
loam prepared for the purpose; the sides are closed with
moulding sand. The slabs, when cast, are rolled, several
"passes" being necessary, and the sheets are annealed at
intervals, and when finally finished are "pickled " to give them
a good surface. For fine work, the surfaces must sometimes
be repeatedly scraped during the process of rolling to remove
surface impurities and defects.
Wire brass is similarly treated, and the plates are then slit
into rods in the " slitting mill," rolled to give them a section
which can be handled in the wire-mill, and the rods are then
drawn as in making iron wire.*
Brass tubes for steam boilers, condensers and other pur-
poses, are usually drawn, as are many other forms of section.
91. Working Brass. — Yellow brass, and several composi-
tions of similar character, are so easily worked cold that
many articles are made by " striking up " in a die, under a
press or a drop-hammer. Where a considerable change of
form is necessary, the work is done by a succession of opera-
tions alternating with annealing. Rolls may often be used to
form brass into the desired shape and they are still oftener
employed to impress a pattern on the sheet.
* Part I, § 138, p. 196.
164 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
" Spinning " is a peculiar and very interesting, as well as
useful process. It is employed in altering the shape of a
disk or of a cylinder which can be " chucked " and held in a
lathe, while the tool of the workman, pressing on the edge,
turns it over and forces it into a new shape.
Spinning brass often consists merely in forming a flat sheet,
turning in the lathe, by the pressure of a smooth burnishing
tool. Chasing is done with a graver, and matting and emboss-
ing with formers and hammers. In burnishing to give high
lustre, the metal is kept wet with sour beer, while the burnisher
by a steady friction produces the polish.
" Burnishing " consists in giving a fine lustrous surface by
the pressure and friction of a smooth, highly polished steel
tool, lubricated well, as above. The surface is first prepared
by giving it a good polish by the usual methods. The
" burnishers " are made of fine steel, carefully polished with
crocus and oil, and kept in the most perfect possible con-
dition.
The working of brass in the lathe requires especial care,
not only in the handling, but also in the form of the tool.
The cutting edge is given a much larger angle than in cutting
iron and steel ; hand-tools require to be given precisely the
right inclination and a constant rotation ; the velocity of
cutting greatly exceeds that usual with iron.
Brass tubes are sometimes made by simply rolling sheet,
brass, cut to exact size, upon a mandrel and brazing or solder-
ing the joint ; but they are more usually " drawn."
The roll and its mandrel are sent through the draw-plate
together and the tube is thus drawn to size and the soldered
lap becomes distinguishable only by the color of the joint.
Locomotive tubes, and others required to bear very high
temperatures and pressures, are drawn solid and seamless.
Brass condenser tubes should be made of copper 70, zinc
30, as prescribed by the British Admiralty. Boiler tubes are
made of copper 18, zinc 32. The metals should be pure.
In many cases peculiar and ornamental shapes are given
by modification of the form of mandrel or of draw-plates.
Patterned sheets are produced by the use of rolls with
BRA SSES AND 0 THER COPPER-ZINC ALLO YS. 1 65
properly cut surfaces. The " die " in which the metal is given
shape under the blows of a " drop," or of a heavy hammer,
is very extensively used in working brass.
92. The Properties of Brasses, as described by the best
authorities, are exhibited in the most concise manner in the
following table, which was originally collated for the Com-
mittee on Alloys of the U. S. Board,* as was that already
given for the bronzes. It includes the results of work done
for that board.
A more complete exhibit of the mechanical properties of
the bronzes and brasses will be given in succeeding chapters
describing investigations, usually conducted by the Author,
as above.
Experimental investigation by Mr. Sperry has shown that
the presence of bismuth, even in as small amount as o.oi per
cent., is very deleterious ; often causing " brasses " to crack
and always producing brittleness.f It is possible that the
presence of this or other elements in minute quantity may pro-
duce that " checking "or cracking of brass rods (Cu. 65, Zn. 35,
with small doses of lead), leaving the mill apparently sound,
after transfer to the warehouse, or even when in the fitting
shop.
* Report, vol. ii, 1881, p 67.
f Trans. A. I. M. E., 1898, p. 427.
1. 66 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
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59, pp. 114-121 ;
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himiques, Paris, 1869.
nal, xlv., 1848. pp. 87
Mag., 18, 1850. pp. 354
p. 161-184 ; ibid.
. 66-68.
, pp. 351-
lic Alloys
, 1859, pp.
H ^
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Bo.— Bolley. Essais echerches
Cr. — Croockewit. Erann's Jo
C. J.— Caert and Johon. Pkil.
Ma.— Mahiessen. Phil. Trans.,
Ml.— Malt. Phil. Mag., v. 21,
Ri. — Ric Annales de chimie,
U. S. B. port of Committee
We. —Wmann. Pogg. An
R
d
I7O MATERIALS OF ENGINEERING— NON-FERROUS METALS,
Note on the Table. — Alloys having the name of Bol-
ley appended, are taken from Bolley's " Essais et Recherches
Chimiques," which gives compositions and commercial names,
and mentions valuable properties, such as are given in the
columns of remarks, but does not give results in figures, as
recorded by other authorities. The same properties and the
same name are accorded by Bolley to alloys of different com-
positions, such as those which in the column of remarks are
said to be " suitable for forging." It might be supposed that
such properties belonged to those mixtures and not to other
mixtures of similar composition. It seems probable, how-
ever, that v/hen two alloys of different mixtures of copper
and zinc are found to have the same strength, color, fracture,
and malleability, it will also be found that all alloys between
these compositions will possess the same properties, and
hence that, instead of the particular alloys mentioned
only being suitable for forging, all the alloys between
the extreme compositions mentioned also possess that
quality.
In the figures given from Mallet under the heads of " order
of ductility," " order of malleability," " hardness," and " order
of fusibility," the maximum of each of these properties is re-
presented by I.
The figures given by Mallet for tenacity are confirmed by
experiments of the Author, with a few very marked excep-
tions. These exceptions are, chiefly, the figures for copper,
for zinc, and for CuZn2 (32.85 copper, 67.15 zinc). The figures
for CuZn2, as given by Mallet, can, in the opinion of the Author,
only be explained on the supposition that the alloy tested was
not CuZn2 (32.85 copper, 67.15 zinc), but another, containing
a percentage of copper probably as high as 55. The figure
for the specific gravity (8.283) given by Mallet, indicates this
to be the case, as does the color. The figure for ductility
would indicate even a higher percentage of copper. The
name " watchmaker's brass " in the column of remarks must
be an error, as that alloy is a brittle silver-white, and ex-
tremely weak metal.
The figures of Calvert and Johnson and Riche, as well as
BRASSES AND OTHER COPPER-ZINC ALLOYS. I /I
those of the Author, give a more regular curve than can be
constructed from the figures of Mallet.
The specific gravities in Riche's experiments were obtained
both from the ingot and from powder. In some cases one,
and in some cases the other, gave highest results. In the
table, under the head of "specific gravity," Riche's high-
est average figures are given, whether these are from the
ingot or from fine powder, as probably the most nearly cor-
rect. The figures by the other method, in each case, are
given in the column of remarks. The figures of Riche and
Calvert and Johnson are scarcely sufficient in number to show
definitely the law relating specific gravity to composition, and
the curves from their figures vary considerably. The figures of
the Author being much more numerous than those of earlier
experimenters, a much more regular curve is obtained, es-
pecially in that portion of the series which includes the yel-
low, or useful metals. The irregularity in that part of the
curve which includes the bluish-gray metals is, no doubt, due
to blow-holes, as the specific gravities were in all cases deter-
mined from pieces of considerable size. If it were determined
from powder, it is probable that a more regular set of obser-
vations could be obtained, and that these would show a higher
figure than 7.143, that obtained for cast zinc. Matthiessen's
figure for pure zinc, 7.148, agrees very closely with that ob-
tained by the Author for the cast zinc, which contained about
I per cent, of lead.
The figures for hardness given by Calvert and Johnson were
obtained by means of an indenting tool. The figures are on
a scale in which the figure for cast iron is taken as 1,000.
The alloys opposite which the word " broke " appears, were
much harder than cast iron, and the indenting tool broke
them instead of making an indentation. The figures of al-
loys containing 17.05, 20.44, 25-52> and 33.94 per cent, zinc,
have nearly the same figures for hardness, varying only from
427.08 to 472.92. This corresponds with what has been stated
by the Author in regard to the similarity in strength, color,
and other properties of alloys between these compositions.
CHAPTER VI.
THE KALCHOIDS AND MISCELLANEOUS ALLOYS.
93. Other Alloys than Bronzes and Brasses exist in im.
mense variety and have numerous applications in the Arts,
although of far less common application than the classes of
alloys already described.
Of these alloys, the most important are those which most
closely resemble the true bronzes and brasses in composition,
as alloys consisting of bronze or brass with which are united
smaller proportions of lead, iron, nickel, antimony, bismuth,
and other common metals. In this class also fall the "Kal-
choids" as the Author would call them, or the copper-tin-zinc
alloys which are usually called brass or bronze accordingly
as zinc or tin predominates. The white " anti-friction " or
"anti-attrition" metals, the fusible alloys, and type and
stereotype metals, all come within this classification.
94. The Kalchoids (Gr. Kalchos), or Copper-Tin-Zinc
Alloys, are of great value and include the strongest, and
probably the hardest, possible combinations of these metals.
They are, in most respects, usually, intermediate between the
brasses and the bronzes obtained by uniting two metals.
According to Margraff, these alloys are often very valu«
able and have the character as per table on next page.
Mackensie finds the alloy, copper 58, zinc 25, tin 17,
excellent for castings and a good statuary bronze ; and pro-
poses copper 50, zinc 22, tin 28, for mirrors for telescopes ;
it is slightly yellow and takes a very fine polish. Bronzes in
which equal parts tin and zinc are used are of common use
for very small articles — as " brass " buttons. Knives for
cotton printers' rolls are often made of copper 82, zinc 10,
tin 8. Depretz' " chrisocalle " is of copper 92, tin 6, zinc 6,
KALCHOIDS AND MISCELLANEOUS ALLOYS.
173
it has a beautiful golden color. Another composition imitat-
ing gold is, copper 81.5, zinc 8, tin 0.5 ; and still another,
which retains its lustre well, is of copper 80, zinc 17, tin 3;
it is used for the small parts of ornamented pistols, etc.
Alloys containing these metals are used for bronze medals,
the zinc and tin being introduced to the extent of from 2 to
8 per cent, and the total of both being usually 10 per cent, or
less. The percentage of zinc is usually kept under 3 or 4 in
ordnance metal.
TABLE XXIII.
COPPER-TIN-ZINC ALLOYS.
NO.
COPPER.
TIN.
ZINC.
REMARKS.
I
100
IOO
IOO
Very white, brittle, subject to liquation.
2
100
50
50
but finer grain.
3
100
25
50
Yellowish tint, hard, fine, not malleable.
4
100
25
25
Brittle.
5
100
20
20
Brittle, hard, yellow.
6
100
16
16
" close grained.
7
100
14
14
Yellow, slightly malleable.
8
IOO
12.5
12.5
" more malleable.
9
100
II
II
« « «
10
IOO
10
10
Fine yellow, fine grain, malleable.
ii
IOO
8
8
Yellow, softer, more malleable.
12
IOO
7
7
Golden, malleable, soft.
13
IOO
6
6
« tt «
The use of 8 to 15 per cent, of tin and 2 per cent, zinc in
alloy with copper is probably as common as the employment
of the bronzes without zinc ; the latter is added to improve
the color. Alloys of copper containing from 3 to 8 or 10 per
cent, zinc and from 8 to 15 per cent, tin are used in engineer-
ing very extensively, the softer alloys for pump-work, the
harder for turned work and for nuts and bearings. An alloy
of 5 per cent, tin, 5 zinc and 90 copper is cast into ingots and
remelted for general purposes. It is tough, strong and
sound. Copper 75, tin 12, zinc 13 makes a good mixture for
heavy journal-bearings. Copper 76, tin 12, zinc 12, is as hard
as tempered steel and was made into a razor-blade by its
174 MATERIALS OF ENGINEERING—NON-FERROUS METALS.
discoverer, Sir F. Chantrey.* When copper and brass are
mixed in equal proportions and their sum is equal to the
weight of tin, the alloy constitutes a solder.
95. Copper, Zinc and Iron unite with some difficulty, and
the presence of iron is thought to make brass harder, to
weaken it, and to increase its liability to tarnish. A ternary
alloy of this character was introduced in England as early as
1822 and was claimed to be stronger and better for the pres-
ence of the iron. An alloy of I per cent, brass with 99 of
iron was advised for castings exposed to corrosion, and Kars-
ten found that it was harder than the cast iron, and considered
it well adapted for use in steam engine cylinders and heavily
loaded journal bearings. Herve found the zinc less desira-
ble in copper-iron alloys than tin. He states that alloys
containing 1.33 to 4 per cent, copper and 0.65 to 3 per cent,
zinc were stronger than the cast iron with which they were
alloyed. Sterro-metal, elsewhere described, is a metal of this
kind, containing also a small amount of tin.
96. Copper, Tin and Iron may be alloyed to make a
ferrous bronze of great value. The introduction of cast-iron
into gun-bronze (copper 89, tin 11, or copper 90, tin 10) is
not only useful, in small amounts as a flux, but this ferrous
alloy is harder and stronger than the bronze alone. This
alloy was made in Russian arsenals about 1820-5, and used
for ordnance. The maximum proportion of iron was from
12 to 25 per cent., according to the use intended. The guns
made of these alloys were found, according to Depretz, to
excel good gun-bronze ordnance in strength and endurance.
Similar alloys were made in France by the Messrs. Darcet f
and by M. Dussaussoy, of the artillery, and on a large scale, in
the government foundry at Douai.
The latter experiments were made with alloys containing :
Copper.
Tin.
Iron.
Copper.
Tin.
Iron.
90
10
6
90
10
4
90
10
3
* Holtzapffel.
f Alliages Metalliques, p. 333.
KALCHOIDS AND MISCELLANEOUS ALLOYS. 1 75
The results were not such as to lead to the adoption of
these alloys in making field guns.
Wrought iron was introduced into standard gun-bronze
by Dussaussoy as early as 1817, using tin-plate for the pur-
pose. When the proportion of iron exceeded 2 per cent, the
result was not satisfactory. For small articles, the ferrous
bronze was found an improvement, it being stronger, harder
and less fusible. Gen. Goguel, of the Russian Army, added
12 per cent, of wrought iron to gun-bronze, and reported that
the ordnance made of this alloy proved much superior to that
made of common gun-bronze. Subsequently, an extended
investigation was made by the order of the French govern-
ment by MM. Gay Lussac and Darcet, and later by M.
Herve of the French Artillery. The former research led to
no result ; the last named investigator concluded that the
use of tin in securing an alloy of iron with copper is of ad-
vantage and that re-fusion is advisable to secure the best
results.
97. Manganese Bronze is said to have qualities resem-
bling those of phosphor-bronze, the introduction of man-
ganese increasing the strength, ductility and homogeneous-
ness of the alloy. The manganese alloys are usually
white tinged with red, ductile, hard and tenacious. They
are often known as white brass, white bronze or white alloys ;
they take a fine polish ; those richest in copper have a
decided rose hue. These alloys, as well as the phosphor-
bronzes, are in somewhat extensive use, especially in Great
Britain.
Copper and manganese alloy easily, or with difficulty, under
different conditions, making a metal of considerable mallea-
bility, red in color, turning green when weather stained. It
is less fusible than copper, lighter in color, and more liable to
tarnish ; it may be made by fusing together copper and the
black oxide of manganese. Manganese bronze contains
iron, also, and is made by melting together copper and spie-
geleisen or " ferro-manganese." When containing 10 per
cent, manganese, the alloy of copper and this metal is dense,
grayish-white with a tinge of red, very ductile and malleable*
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and of rather a short fracture ; with 20 per cent, manganese,
the color is silver-white to tin white, strong and ductile, with
a fine lustre ; with 30 per cent, manganese, the properties
remain little altered ; with 40 per cent., the alloy becomes
iron-gray, malleable and ductile, very strong, fracture inclined
to fibrous. Thus, according to Berthier, all these alloys are
ductile, strong, compact and homogeneous.
Manganese-bronze is very similar in its general character,
istics to phosphor-bronze ; but is a white alloy and differs in
being a triple compound of- the metals, copper, tin and man-
ganese, instead of an alloy of copper and tin fluxed with a
metalloid. It possesses some peculiarities which give very
great value to this metal as a material of construction. It is
remarkably hard, tough and elastic, has rather a high elastic
limit, as compared with ordinary bronze, and is found to be very
durable when used for bearings of machinery. A common pro-
portion of its constituents is, copper, 88, tin, 10, manganese, 2.
98. Preparation and Uses of Manganese-Bronze. — As
described by the inventor, Mr. P. M. Parsons, white bronze,
or manganese-bronze, is prepared by combining ferro-man-
ganese, in different proportions, with various bronze alloys,
thus producing qualities suited to various uses. The ferro-
manganese is first subjected to a refining process, by which
the silicon is eliminated, and the proportion between the iron
and manganese adjusted in various degrees, for use according
to the quality of bronze to be produced. To effect this com-
bination, the temperature of the copper must be brought up
to the melting point of the ferro-manganese, which is melted
separately and then added in a fluid state.
The effect of this combination is similar to that produced
by the addition of ferro-manganese to decarbonized iron in
the Bessemer converter. The manganese in its metallic state
having a strong affinity for oxygen, cleanses the copper of
oxides, and renders the metal more dense and homogeneous.
A portion of the manganese is utilized in this manner, while
the remainder, with the iron, becomes permanently combined
with the copper, and plays an important part in improving
and modifying the quality of the bronzes prepared from the
KALCHOIDS AND MISCELLANEOUS ALLOYS. 1 7?
copper thus treated, the effect being to increase their strength,
hardness, toughness in various degrees, according to the
quality and quantity of the ferro-manganese employed.
Manganese, when once incorporated with the copper, is not
driven off by remelting ; the quality of the manganese-bronze
is improved by remelting.
Manganese-bronze, as is stated, when forged, is remarkable
for its strength and toughness, having an average tensile
strength equal to mild steel, and elongating as much before
breaking. It is suitable for forgings of all kinds, for bolts
and nuts for engine and machine work, for ships' bolts, rud-
der and other fittings, screws, pins, nails, pump-rods, wire,
and for all purposes for which yellow metal, brass, and cop-
per are employed. In forging this metal, it should be heated
to a clear cherry red (not bright), when it may be hammered,
rolled, pressed, or worked in any way as long as it retains
any color. It should not be worked at a black heat, but
when the color is just fading it should be reheated.
In rolled sheets and plates it can be worked both hot and
cold. In working hot, the instructions given for forgings
should be followed. The metal can be rolled, stamped,
pressed, and worked cold like brass or copper, being annealed
as required. It is stronger, stiffer, and harder than copper,
brass, or yellow metal, for which it can be substituted for
purposes to which these are applied.
The rods, plates, sheets and angles are supplied of mild,
medium, or high qualities, as required. The mild and medium
qualities have a tensile strength of 28 tons per square inch
(4,410 kgs. per sq. cm.), with an elastic limit at 40 per cent,
and stretch from 28 to 45 per cent, before breaking. These
qualities can be worked and riveted up cold, and are claimed
to be greatly superior to yellow metal or gun metal.
When ships' screws are made of this material, they are
given less thickness than when made of mild steel or of com-
mon bronze; it is not subject to alteration of form when
taken from the mould or by the annealing which must be
done with steel castings ; it retains a clean surface remarkably
well, but its cost is considerable.
12
178 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The ferro-manganese used to mix with gun metal con-
tains from 10 to 40 per cent, of metallic manganese ; with
brass alloys, 5 to 20 per cent., and with bronze alloys, the
proportion lies between the above, according to the propor-
tions of tin and zinc employed. To prepare ferro-manganese
containing a given amount of metallic manganese, the invent-
or melts rich ferro-manganese, containing up to 70 per cent.,
in a crucible under powdered charcoal, and with a quantity of
the purest wrought-iron scrap. If it is desired to employ a
ferro-manganese to mix with any of the alloys containing 20
per cent, of manganese, a ferro-manganese containing 60 per
cent, of metallic manganese, and, say, I per cent, of silicon,
is melted with wrought-iron scrap, in the proportion of 100
of ferro-manganese to 300 scrap. Then a ferro-manganese
containing 20 per cent, of metallic manganese will be ob-
tained, in which there is only one-third of I per cent, of
silicon.
Dry sand or loam moulds are recommended for casting.
Metal moulds render the alloy somewhat harder and closer in
texture.
Manganese-bronze is said to be much less subject to cor-
rosion in salt water than is pure copper. Alloys containing
from 75 to 85 per cent, copper are most usually adopted for
machinery. Zinc often forms a constituent of these alloys, in
the proportion of from 2 to 10 per cent.
The addition of manganese to bronzes and brasses gives
them much lighter color, greater hardness and tenacity, with-
out proportionally decreasing ductility and resilience. Cop-
per and manganese alone form white alloys of great hardness,
strength and ductility. Some of these alloys forge well and
can be rolled with ease. They are somewhat susceptible
to the action of the atmosphere at high temperature, and
should be worked as little and at as low temperature as pos-
sible.
99. Aluminium- Bronze. — Aluminium is added to copper
and to the bronzes and brasses with good results. The alloy,
copper 90, aluminium 10, may be worked cold or hot like
wrought iron, but not welded. Its tenacity is sometimes
KALCHOIDS AND MISCELLANEOUS ALLOYS.
179
nearly 100,000 pounds per square inch (7,030 kilos per square
mm.), and its average is not far from three-fourths as great.
It is hard and stiff and very homogeneous. Wire has been
given a tenacity exceeding 125,000 pounds per square inch
(8,776 kilos per square mm.). Its specific gravity is 7.7. In
compression this alloy has been found capable of sustaining a
little more than in tension (130,000 pounds per square inch,
9,139 kilos per square mm.), and its ductility and toughness
were such that it did not even crack when distorted by
this load. It is so ductile and malleable that it can be drawn
down under the hammer to the fineness of a cambric needle.
Measuring its stiffness, the Messrs. Simms found * that it had
three times that of gun -bronze and 44 times that of brass.
It works well, casts well, holds a fine surface under the tool,
and when exposed to the weather; and it is, in every respect,
considered the best bronze yet known. Its high cost alone
prevents its extensive use in the arts. Alloying 2 to 8 per
cent, copper with aluminium raises its tenacity 65 to 90 per
cent., making it, weight for weight, stronger than machinery
steel, f Pure, it has a tenacity of about 30,000 Ibs. per square
inch, and a modulus about 11,000,000.
The density of aluminium-bronze has been determined
by M. Riche,^: with the following results :
BRONZE CONTAINING TEN PER CENT. OF ALUMINIUM.
DENSITY.
I.
WT. = I20*r.568.
II.
WT. = 120^ .275.
7.705
7.706
7.706
7-707
7-703
7.703
7.701
7.699
7.704
7.704
7-705
7 707
7.704
7.702
7.702
7.703
After tempering
After tempering
After annealing
After impact .. .
After tempering
After impact
* Ure's Diet., Art. Aluminium.
f Railway Review, Jan. 7, 1891.
% Ann de Chimie, vol. xxx., 1873, pp. 351-419.
Appendix.
180 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
BRONZE CONTAINING FIVE PER CENT. OF ALUMINIUM.
DENSITY.
WT. = I29*r. 575.
II.
WT. = I29Rf.l6l.
8.252
8.259
8.255
8.257
8.257
8.264
8.263
8.263
8.262
8.259
8.262
8.262
8.262
8.264
8.264
8.265
After tempering.
After tempering .. ..
After annealing
After impact . .
After tempering
Tempering, annealing, and mechanical action produce no
noticeable variation in the volume.
Adding 5 to 6 per cent, copper to aluminium doubles its
tenacity, and higher proportions are sometimes advantageous.
100. Uses of Aluminium-Bronze. — Aluminium-bronze,
composed of 9 parts copper and I part aluminium, was pro-
posed in 1864 as a material for small coins, and with this ob-
ject in view the assayer of the United States mint made a
number of careful experiments with it. The assayer states
that aluminium-bronze possesses much greater hardness than
copper alone, but less malleability and ductility. When
rolled into sheets, it requires annealing at every third pas-
sage through the rolls ; when drawn into wire it must also be
frequently annealed. To strike a coin of this bronze required
unusual force. It tarnishes quite readily, but not more so
than copper.
Aluminium-bronze containing 7^ per cent, of aluminium
is greenish in color, according to Morin, while other compo-
sitions on either side are golden. Even I per cent, added to
copper causes a considerable increase in ductility and fusi-
bility, and enables it to be used satisfactorily in making
castings. Two per cent, gives a mixture used for castings
which are to be worked with a chisel. The standard alumin-
ium-bronze— 10 per cent, aluminium — is brittle after the
first fusion, but becomes more ductile as well as stronger by
repeated refusion. It makes good castings, is easily worked,
KALCHOIDS AND MISCELLANEOUS ALLOYS. l8l
and may be forged at a red heat, and is fairly ductile under
the hammer even when cold. It is softened by sudden cool-
ing from a red heat. It takes a fine polish, is a half stronger
than good wrought iron in tension, but has less strength in
compression. Its coefficient of expansion is small at ordinary
temperatures. Its liability to crack in large masses makes it
difficult to get large castings. It has great elasticity when
made into springs ; it is found useful for watches, and has the
decided advantage over steel of being but little liable to oxi-
dation ; the addition of 5 per cent, silver is advised to pure
aluminium to make springs. Kettles of this alloy have been
used in making fruit syrup and preserves.
The alloy of aluminium with 4 to 5 per cent, silver is used
in making balances for chemists. The introduction of a very
minute proportion of bismuth makes this metal very brittle.
Steel containing but 0.08 per cent, aluminium is said to be
greatly improved by its presence.
An alloy of 2 or 3 copper and 97 or 98 aluminium is found
useful in making ornamental silver-colored castings which are
to be chased and engraved.
The alloys of aluminium and copper may be made by fus-
ing together the oxides with metallic copper and enough car-
bon and flux to reduce them. The electric arc is the usual,
and only commercial, reducing agent for the Cu.-Al. alloys,
and the aluminium bronzes are now all made in this way.
101. Copper and Nickel are quite easily alloyed, giving
a metal of usually white color, hard, rather brittle, and quite
easily oxidized. When the nickel forms 30 per cent, of the
whole, the alloy is easily fused, strong, and tough, of a silvery-
gray color, and slightly magnetic. White copper and Ger-
man silver are used for high electrical resistance.
Copper and nickel unite in a wide range of proportions.
In color they range from the red of copper to the blue-white
of nickel, according to their proportions. Adding nickel in
the proportion of o.io, the alloy is very ductile, light copper-
red in color, and moderately strong; with 0.15 nickel, the
color becomes very light red and the ductility is still great ;
0.25 nickel gives an alloy nearly white; 0.30 nickel produces
1 82 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
a silver-white metal. Berthier's alloy, copper 0.682, nickel
0.318, is fusible, ductile, strong, bluish-white, slightly magnetic
and somewhat crystalline near the surface.
A " white copper," Cu. 70, Ni. 18, Zn. 12, has a tenacity of
about 60,000, ductility 10 to 15 per cent.
Nickel coinage is now used by several nations; it was
first privately coined by Feuchtwanger, of New York City, in
1837 ; Switzerland began using it in 1850, the United States
in 1857, and Belgium in 1860. The U. S. coins now contain
copper 75, nickel 25.
102. German Silver. — Copper, zinc, and nickel alloy
readily. These compositions were used at a very early date
in China, and have been known as packfong, tutenag, and
white copper. The East Indian or Chinese tutenag is a
grayish-white alloy, somewhat sonorous, and brittle. Its
composition has been given as copper 44, zinc 40, nickel 16.
The other alloys above named are nearly silver-white, malle-
able hot or cold, have a beautiful lustre, and very sonorous.
The specific gravity is 8.5. Alloys of European manufacture,
of similar characteristics, are now common. Viennese alloys
have been found by Gersdorff to contain : —
Table utensils ; copper, 50 ; zinc, 25 ; nickel, 25.
Ornaments *' 55; " 25; " 20.
Sheet metal " 60; " 20; " 20.
Frick's alloys contain copper, 50 to 55; zinc, 30 to 31;
nickel, 17 to 19. These are white and hard but ductile, and
have a specific gravity from 8.5 to 8.6; they are used in
making table utensils and ornamental objects. The alloy,
copper 56, zinc 5> and nickel 39, makes a fine white metal of
the same class with the preceding.
German silver, as made by good makers, consists usually of
Copper 60
Zinc 20
Nickel 20
100
KALCHOIDS AND MISCELLANEOUS ALLOYS. 183
Guillemin introduces sodium, thus:
Copper 58.00
Zinc 16.65
Nickel 25.00
Sodium 0.35
Sound castings are secured by the use of borax, glass, or
other good flux. German silver is rolled cold, and the rolls
are necessarily made of very great strength ; frequent anneal-
ing is necessary during the process.
103. Copper and Iron unite, when the latter is in small
amount, to produce a stronger metal than can be obtained
without the iron, even when the copper is alloyed with other
strengthening elements ; and iron forms a part of nearly all
manganese bronzes, of the bronze known as Austrian " sterro-
metal," and of various other useful compositions. The
ductility is rather improved than otherwise.
Copper and iron unite at high temperatures, if the heat is
sufficiently prolonged, and in any proportions. The addition
of copper to iron causes brittleness, or " red-shortness." The
Author has found that minute doses of copper confer in-
creased strength on some steels, and Tredgold states that the
same effect is observed on cast iron. Berthier and Rinmann
think that one per cent, copper will have a good effect on
cast iron.
The color of the alloy changes, losing the gray and
becoming red, as the proportion of copper increases, up to
equal parts copper and iron, when the alloy loses all tint of
gray. An alloy of copper 66.67, iron 33-33> is tne strongest of
these alloys. Mushet has made a number of these alloys. He
finds that the presence of carbon causes difficulty in making
them, Karsten found that the copper-iron alloys do not as
readily dissolve in sulphuric acid as does iron.
A ductile alloy was made by Rinmann of copper 16, iron
i ; it is magnetic, harder than copper, and the fractured sur-
face has a beautiful red color. Eight parts copper and from
1 84 MATERIALS OF ENGINEERING-NON-FERROUS METALS,
I to 4 parts iron produce alloys harder than the preceding,
but not appreciably less ductile or less red than copper.
Copper and cast iron alloy to form a strong metal, also.
Riche has successfully produced alloys of copper and
iron ; but they are somewhat variable in composition and
quality; thus:
He heated in a temperature sufficient to melt cast iron-
Copper 90
Cast iron 10
The ingot obtained contained, at the top, iron uncom-
bined.
He heated very hot and held some time in fusion —
Copper 90
Rivets IO
The ingot obtained furnished upon analysis —
Top i, 600 iron.
Bottom 365 iron.
He heated very hot and kept melted some time —
Copper 96
Rivets 6
The metal appeared very homogeneous. Its density,
taken at two different points, gave —
8.881
8.876
The metal is easily forged, stretches and coils upon itself
without breaking. It is rolled with such facility that, without
annealing, a bar of it can be reduced from a thickness of 9
millimetres (0.35 inch) to that of I millimetre (0.04 inch). Its
tenacity exceeds that of copper.
Examining with a magnifying glass the plates I millimetre
in thickness mentioned above, gray spots may be seen at
certain points, but analysis of these points shows no material
KALCHOIDS AND MISCELLANEOUS ALLOYS.
I85
difference between them and other portions. There was
found —
Iron 5-383 5.285 5.236
This substance made very hot in the crucible gives a but-
ton in which there remains only —
Iron 0.167 per cent.
These two metals were alloyed in variable proportions,
melted in earthen tubes 15 centimetres (5.9 inches) in length,
and after being kept three hours in fusion, were left to cool
slowly. Analysis then gave : —
IRON, PER CENT.
Top of bar.
Bottom of bar.
Density.
12 60^
4-545
8.839 to 8.771
2
9. 2QO
<* 680
6.876
J.V0U
3.652
A .
4.6lQ
A, C2O
4 J
4.226
4.288
8.885
6
2.Q5O
2.600
The addition to copper of small quantities of foreign
matter, iron, for example, increases the porosity, as do small
quantities of oxygen. The copper acquires tenacity and
elasticity by this addition of iron, while retaining some malle-
ability.
104. Copper-Antimony Alloys. — Antimony, added to the
copper-tin alloys, rich in the latter metal, is largely used for a
lining metal in journal-bearings. Babbitt's Metal is the best
known of these metals, and contains 4 parts copper, 96 of
tin, 8 of regulus of antimony. It is made* by melting 4 parts
of copper, adding 12 parts best tin, 8 of regulus of antimony,
then 12 of tin while cooling the molten mixture. Of this
*' hardening metal," one part is added to twice as much tin
to make the lining metal. Copper I, tin 9, without antimony,
is also known as Babbitt Metal ; it is a usual composition in
* Haswell.
1 86 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
government work. This composition has been found ex-
cellent in locomotive practice and more satisfactory than that
containing antimony. Cu. 4, Sb. 8, Sn. 12 works well.
Copper and antimony alloy in the proportion, copper 85,
antimony 15, to form, according to Karsten, a brittle metal
of little value. Equal parts copper and antimony unite to
make a brittle, light-violet colored alloy, of which no use is
made in the arts.
105. Copper and Bismuth unite readily and at a temper,
ature below that of fusion of copper. The addition of bis-
muth causes brittleness, and all ductility is lost when the
proportion approaches I per cent. Minute quantities may
be added to copper, and if not above 0.5 per cent, the alloy
may be hammered and rolled ; exceeding that proportion,
the alloy becomes brittle with working and too much so to
be safely used. The color of the alloy is light red ; its
density is the mean of its constituents. Prince's Metal is
said to be an alloy of copper and bismuth.
106. Bismuth-Bronze. -- Webster's bismuth-bronze is
made of various proportions. According to the statement of
the discoverer, its composition and qualities are as follows :
For a hard alloy, take I part of bismuth and 16 parts
of tin, both by weight, and, having melted them, mix them
thoroughly. For a hard bismuth bronze, take 69 parts of
copper, 21 parts spelter, 9 parts nickel and I part of the
alloy of bismuth and tin. This bismuth-bronze is a hard,
tough and sonorous metallic alloy, which is proposed for
use in the manufacture of screw-propeller blades, shafts,
tubes and other appliances employed partially or constantly
in sea water. In consequence of its toughness it is thought
to be well suited for telegraph wires and other similar pur-
poses where much stress is borne by the wires. From
its sonorous quality it is well adapted for piano and other
wires. For domestic utensils and articles exposed to at-
mospheric influences, use I part bismuth, one part aluminium
and 15 parts tin melted together to form the separate or
preliminary alloy, which is added in the proportion of I per
cent, to the above described alloy of copper, spelter and nickel.
KALCHOIDS AND MISCELLANEOUS ALLOYS. 187
This bronze forms a bright and hard alloy suited for the
manufacture of utensils or articles exposed to oxidation.
107. Copper and Cadmium form an alloy similar in char-
acter to those of bismuth and copper.
108. Copper and Lead unite with difficulty, and a good
alloy can only be obtained with a small quantity of lead.
One-tenth per cent, lead gives a mixture observably less duc-
tile than copper, and when three times this quantity is intro-
duced the alloy has the singular property of working better
cold than hot. The combining temperature is so high that
the lead usually gives off fumes of oxide ; the cooling should
be done rapidly. The alloy has a lower density than the
mean of its constituents and is rarely stable.
An alloy of copper 20, lead 80, is sometimes used in type-
foundries for large type. This, like all those alloys, if kept
in a state approaching that of fusion, is subject to separation
or " liquation," the lead separating and leaving the copper in
a porous mass. When the alloy oxidizes, the oxide is found
to contain much more than the proportion of lead contained
in the alloy. Common " pot-metal " contains 20 per cent,
lead. It is brittle when heated ; larger amounts of lead
render the alloy difficult to work and injure it seriously. The
fusibility is greatly increased by the presence of the lead.
Copper and lead are not easily alloyed, but form, when
combined, a metal of gray color, brittle, and of feeble affinity.
An alloy of lead 4, copper i, is sometimes used for large type.
The constituents are very liable to separation, when kept
molten, by liquation. Norway copper, from Drontheim, con-
tains a half per cent, lead ; it is preferred in making brass.
Other coppers often contain \y2 or 2 per cent. lead.
109. Copper and Silicon, with or without tin, may be
alloyed to form " silicon-bronze." Weiller's alloy is made
by the introduction of sodium to reduce silica in the cru-
cible. This bronze has been used to take the place of
phosphor-bronze for telegraph wires in Southern Europe.
The inventor recommends the following proportions : fluo-
silicate of potash, 450 grams; glass in powder, 600 grams;
chloride of sodium, 250 grams ; carbonate of soda, 75 grams;
1 88 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
carbonate of lime, 60 grams ; and dried chloride of calcium,
500 grams. The mixture of these substances is heated, in a
plumbago retort, to a temperature a little below the point
when they begin to react on one another, and it is then placed
in a copper or bronze bath, when the combination of the
silicium takes place, as already said.
HO. Use of Silicon-Bronze. — The superiority of silicon
is claimed to be due to its better adaptability to being
worked at a high temperature, by its penetrating the metal
better, and, consequently, insuring the indispensable homo-
geneity. It is said of silicon-bronze, that it possesses the
conducting qualities of the best copper, with the resisting
qualities of the best iron, and that each of these advantages
may be varied at will, at the expense of the other.
Applied to aerial telegraph lines, the present galvanized
wires of the great lines, 5 millimetres (0.2 inch) in diameter,
and weighing 155 kilos per kilometre (120 pounds per mile),
can be replaced by silicon-bronze wires of 2 millimetres (0.08
inch) in diameter, weighing only 26 kilos to the kilometre
(20 pounds per mile) ; while the ordinary steel telephone
wires of 2 millimetres (0.08 inch) diameter, and 25 kilos to
the kilometre (20 pounds per mile), may be replaced by sili-
con wires of only ITV millimetre (0.04 inch) in diameter, and
weighing 8 kilos to the kilometre (6 pounds per mile).
in. Copper, Tin, and Lead alloy readily, and are thus
used in the manufacture of art-castings, for which purpose
this composition was also used by the ancients. Statues made
by the Romans have been found to contain lead in a propor-
tion equal to about one-fourth that of the tin. Klaproth finds
in an antique mirror, copper 62, tin 32, lead 6. The pres-
ence of lead in bronze promotes durability under wear.
Bronzes containing 2 to 15 per cent, lead make the best
of bearings. Lead is very liable to promote liquation.
112. Copper, Tin, Antimony, and Bismuth united, form
a " pewter, " once in common use for tableware ; it is a beau-
tiful alloy resembling silver, but too readily tarnished, and
too soft to be very valuable. It contains copper 3^, tin
88^, antimony 7, bismuth I.
KALCHOIDS AND MISCELLANEOUS ALLOYS. 189
113. Copper, Tin, Zinc, and Iron are found in bell metal,
and make, in certain proportions, an excellent alloy. The
alloy is not made for the market. The above metals, alloyed
with nickel, form "melchior" a composition containing: of
copper, 55 ; nickel, 23; zinc, 17; iron, 3 ; tin, 2. Argenthal
is a similar metal. They are white alloys and used for
ornamental castings. Their lustre is silvery and quite per-
manent.
114. Copper and Mercury alloy freely. A composition
of 25 parts copper in fine powder, obtained by precipitation
from solutions of the oxide by hydrogen, or of the sulphate
by zinc, washed with sulphuric acid and amalgamated with
7 parts of mercury, after being well washed and dried, is
moderately hard, takes a good polish, and makes a fine solder
for low temperatures. It will adhere to glass.
Droniers malleable bronze is made by adding one per cent,
of mercury to the tin when hot, and this amalgam is carefully
introduced into the molten copper.
115. Complex Copper Alloys. — An alloy imitating gold
is made thus : Melt together pure copper, platinum, and
tungstic acid, in proportion as follows : Copper 800, 25 of
platinum, 10 of tungstic acid, 175 of gold. When com-
pletely melted, stir and granulate by running into water con-
taining 500 parts of slacked lime, and the same of carbonate
of potash for every cubic metre of water. The granulated
metal is next collected, dried, and, after remelting in a cru-
cible a small quantity of fine gold is added. An alloy results
which, when run into ingots, presents the appearance of red
gold of the standard of 750-1 oooths, bears a strong acid test,
and has nearly the density of gold.
A so-called unoxidizable alloy has the following compo-
sition : Iron, 10 parts; nickel, 35 parts; brass, 25 parts; tin,
2O parts ; zinc, 10 parts. The castings made of this alloy are
cleaned by immersion, while white hot, in a mixture of 60
parts sulphuric acid, 10 parts nitric acid, 5 parts hydrochloric
acid, and 25 parts of water.
Copper and all its alloys should be avoided where super-
heated steam is employed.
190 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
116. Bismuth Alloys. — The properties of alloys of bis-
muth and other useful metals are given in considerable detail
by Guettier, as follows : — *
Alloys of Bismuth and Copper. — These alloys are easily
made, notwithstanding the difference in the points of fusion
of the two metals. They are brittle, and of a pale red color,
whatever the proportions employed. For description of the
useful alloys with copper, see Articles 105-6, page 186.
Alloys of Bismuth and Zinc. — These alloys are seldom
made, and produce a metal more brittle, exhibiting a larger
crystallization, with less strength, than zinc or bismuth taken
singly. They have little value in the arts.
Alloys of Bismuth and Tin. — The combinations of bismuth
and tin take place easily and in all proportions. A very small
quantity of bismuth imparts to tin more hardness, sonorous-
ness, lustre, and fusibility. On that account, and for some
purposes, a little bismuth is added to tin in order to increase
its hardness. But bismuth, being easily oxidized, and often
containing arsenic, the alloys of tin and bismuth would be
dangerous, if used for the manufacture of culinary vessels.
The alloys of bismuth and tin are more fusible than either of
the metals taken separately. An alloy of equal parts of the
two metals is fusible between a temperature of 100° to 150°
Centigrade (2i2°-3O2° F.). When tin is alloyed with as little
as 5 per cent, of bismuth, its oxide acquires the peculiar yel-
lowish-gray color of the bismuth oxide. According to Rud-
berg, melted bismuth begins to solidify at 264°, and tin at
288° C. (507°-55o° F.). For the alloys of the two metals the
" constant point " is 143° C. (289° F.).
Alloys of Bismuth and Lead. — These two metals are al-
loyed by simple fusion, with ordinary precautions. The
alloys are malleable and ductile as long as the proportion of
bismuth does not exceed that of lead ; they are more tena-
cious than lead. The alloy of bismuth 2 and lead 3 is ten
times harder than pure lead. The compounds of bismuth
and lead generally have a dark gray color with a tint inter-
mediate between the color of tin and that of lead. Their
* Guettier : " Guide Pratique des Alliages Metalliques." Paris, 1865.
KALCHOIDS AND MISCELLANEOUS ALLOYS. IQI
fracture is lamellar, and their specific gravity greater than
the mean specific gravity of either metal taken singly. An
alloy of equal parts of bismuth and lead has a specific gravity
of 10.71. It is white, lustrous, sensibly harder than lead, and
more malleable. The ductility and malleability diminish with
an increased proportion of bismuth, while they increase with
the excess of lead in the alloy. An alloy of bismuth I and
lead 2 is very ductile, and may be rolled into thin sheets with-
out cracking. Berthier gives its point of fusion as 166° C.
(331° F.).
Alloys of Bismuth and Iron. — Authorities disagree as to
the possibility of combining bismuth and iron. The presence
of bismuth in iron tends to render this metal brittle.
Alloys of Bismuth and Antimony. — These alloys are gray-
ish, brittle, lamellar, like the alloys of bismuth and zinc, and
have no value in the arts.
It will be seen from the preceding that the alloys of bis-
muth are not at present of importance in the arts, excepting
the fusible alloys made of bismuth and certain white metals,
such as tin, lead, etc. The alloys of bismuth with tin, the
latter predominating, are the most interesting. The great fusi-
bility of the alloys of bismuth and lead will have the effect
of making these alloys useful, as also those with tin, as soon
as bismuth can be obtained in abundance and at small cost.
The action of the bismuth in alloys is to increase their
hardness, fusibility, and brittleness. But, although bismuth
renders brittle the metals with which it combines, it does so
to a considerably less degree than either arsenic or antimony.
Tin and Bismuth alloy to form metals of greater hardness,
sonorousness, and fusibility than either tin or bismuth. Equal
parts give an alloy which melts at about 300° F. (150° C.
nearly), and is called " cuttanego," of which the oxide makes
a white enamel. Tin 2, bismuth I, gives an alloy melting at
about 325° F. (165° C.), and the alloy tin 8, bismuth I, at
480° F. (200° C.). Tin itself melts at about 440° F. (228° C.),
bismuth at 510° F. (265° C.).
Riche gives the densities of alloys of tin and bismuth as
follows :
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
THEORETICAL
DENSITV.
EXPERIMENTAL
DENSITY.
DIFFERENCE.
REMARKS.
Bi2 Sn
Q.4.26
0.4-14
+ .OO8
Bi Sn
Q.I3C
q. 145
+ .OIO
Bi Sna
8 74.O
8 754.
+ .OI4
Bi Sns
8.4QI
8.506
+ .OI<
Bi 8114
8 306
8 327
+ -O2I
Bi Sns
8 174.
8 IQQ
+ .02^
Maximum contraction.
Bi Sn6
8. 073
8. 007
+ .024
Bi Sn?
7QQ4
8.CI7
+ .023
The maximum contraction should take place in the alloy
Bi Sn5, which is a silvery-white metal formed of little crystal-
line grains commingled. This alloy was not attacked by dis-
tilled water ; at the end of several hours it retained its brill-
iancy and its silvery lustre.
The maximum contraction is seen with the alloy Bi
Pb8, and on either side of this alloy a very regular diminution
in contraction will be noticed. The differences being very
great both between the theoretical and experimental density,
and between the density of each alloy and that of its neigh-
bors, he made but two determinations for each alloy. As
analysis of the ends and of the middle of the ingot formed by
the alloy BiPb3 gave the same numbers, it seems, therefore,
that this alloy should be considered as a chemical com-
pound.
Lead and bismuth unite readily, when fused, to form a
malleable alloy if the lead is in excess, but a brittle compound
if the bismuth is present in large amount. Its color is dark
gray, fracture often lamellar, and the density greater than
that given by calculation. Equal parts give an alloy having
the specific gravity 10.71, white, lustrous, harder and also
even more malleable than lead; with lead 3, bismuth I, an
alloy of 6 times the tenacity of lead is produced ; lead 2, bis-
muth i, gives a very malleable alloy, easily rolled into thin
sheets, melting at 325° F. (165° C), the melting-point of the
alloy of equal parts.
Riche finds the following densities of alloys of lead and
bismuth :
THE KALCHOIDS AND MISCELLANEOUS ALLOYS. IQ3
Density of the lead n . 364
Density of the bismuth 9. 830
THEORETICAL
DENSITY.
EXPERIMENTAL
DENSITY.
DIFFERENCE.
REMARKS.
Bi2 Pb
IO.OQQ
10. 232
+ O \'\'\
Bi Pb
10 288
IO ^IQ
+ o 231
Bi Pb2 . . .
TO ^^6
10 cni
+ o ^Q^
Bi2 Pb5
10 622
n .038
+ o 416
Bi Pb3
Bi2 Pb7
10.448
10 748
11.108
ii 166
+ 0.660
_l_ o 418
Maximum contraction.
Bi Pb4 . . .
TO 7Q7
II IQJ.
j- o ^Q7
Bi Pb5.
IO 874
ii 209
J-O. ^^
Bi Pb6
IO.CH2
ii .225
+ O.2Q1}
Bi Pb7
IO Q7Q
II .2^
+ O.254
117. Bismuth, Tin, and Lead form a series of " fusible
alloys " used in obtaining impressions from objects made of
the less fusible metals, and in making " fusible plugs " and
other safety apparatus or gauges of temperature. These al-
loys are also used as " soft solders."
Newton's alloy consists of bismuth 50, tin 30, lead 20;
it melts at about the boiling-point of water. These alloys
are all weak and are of a dull gray color and tarnish readily.
Darcet's alloys are the following :
TABLE XXIV.
DARCET'S FUSIBLE ALLOYS.
NO.
BISMUTH.
LEAD.
TIN.
REMARKS.
I
7
2
4
Softens at the boiling-point of water.
2
8
2
6
Ditto ; easy of oxidation.
3
8
2
4
Ditto : like butter.
4
16
4
7
Softens still more.
5
9
2
4
" less.
6
16
5
7
Becomes nearly liquid at boiling-point.
7
8
3
4
quite " "
8
8
4
4
" very " "
9
16
9
7
Ditto.
10
8
5
3
Melts at 205° F. (95° C.).
ii
8
6
2
Ditto.
12
8
7
I
Softens.
13
16
15
I
Does not melt at 212° F. (100° C.).
13
194 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The fusible metals of most common use are :
D'Arcet's : Bismuth, 8 ; lead, 5 ; tin, 3 parts.
Walker's : Bismuth, 8 ; tin, 4 ; lead, 5 parts ; antimony, l
part. The metals should be repeatedly melted and poured
into drops, until they can be well mixed previous to fusing
them together.
Onion's : Lead, 3 ; tin, 2 ; bismuth, 5 parts. Melts at
197° Fahr. (93° C).
If, to the latter, after removing it from the fire, one part
of warm quicksilver be added, it will remain liquid at 170°
Fahr., and become a firm solid only at 140° Fahr. (77° C. :
60° C.).
Another : Bismuth, 2 ; lead, 5 ; tin, 3 parts. Melts in
boiling water.
They are frequently used to make toy spoons, which sur-
prise the uninitiated by melting in hot liquors. A little mer-
cury may be added to lower the melting points.
The first two are specially adapted for making electrotype
moulds. French cliche moulds are made with the second
alloy. These alloys are also used to form pencils for writing,
also as metal baths in the laboratory, or for soft soldering joints.
The committee of the Franklin Institute, experimenting
on steam boilers in 1836, made an examination on the be-
havior of the " fusible metals,'-' and reported :
That the impurities of the commercial metals, lead, tin
and bismuth, do not usually affect the melting points of
these alloys ; and that the compounds made by alloying
them in chemically equivalent proportions do not present
the characteristics of chemical compounds. They found that
alloys ranging between SnPb and SnPb6 give nearly the
same temperatures of fusion, but differ in their rates of
change from the solid, through the plastic to the liquid state.
The temperatures of casting and rates of cooling do not
affect the melting points. Separation of the metals could be
effected by pressure — a conclusion confirmed by the later ex-
periments of Weems; these alloys, when used in "safety
plugs " of steam boilers, should not be exposed to the pres-
sure of the steam. Very little change is effected in the
THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 195
melting point of an alloy of equal parts lead and tin by
adding tin ; its melting point was found to be a few degrees
lower than reported by Parkes.
Parkes and Martin obtain the following :
TABLE XXV.
FUSION OF ALLOYS OF BISMUTH, TIN AND LEAD.
BISMUTH.
LEAD.
TIN.
TEMPERATURE.
Parts.
Parts.
Parts.
Fahr.
Cen.
8
5
3
202°
94-44°
8
6
3
208
97.78
8 .
8
3
226
107 64
8
8
4
236
112. 2O
8
8
6
243
II6.05
8
8
8
254
122. IO
8
10
8
266
I27.6O
8
12
8
270
130.90
8
16
8
3OO
147.40
8
16
10
304.
149 60
8
16
12
294
141.90
8
16
14
290
139.70
8
16
16
2Q2
140.80
8
16
18
298
144.10
8
16
20
304
147.40
8
16
22
312
152.80
8
16
24
316
154.00
8
18
24
312
152 90
8
20
24
3IO
151.90
8
22
24
308
151.80
8
24
24
310
152.90
8
26
24
320
158.40
8
28
24
330
163.00
8
30
24
342
170.50
8
32
24
352
176.00
8
32
28
332
165 oo
8
32
30
328
163.90
8
32
32
320
158.40
8
32
34
3i8
157-30
8
32
36
320
158.40
8
32
38
322
159-50
8
32
40
324
160.60
The thermometer is observed to rise about one degree,
Fahr., at the instant of solidifying.
These alloys are especially valuable for baths used in
tempering steel articles of small size. They give a very
exact temperature, which may be adjusted to the purpose
196 MATERIALS OF ENGINEERING— NOX-FERROUS METALS.
intended. They are used by placing the article on the sur-
face of the unmelted alloy, and gradually heating until fusion
occurs and they fall below the surface, at which moment their
temperature is right; they are then removed and quickly
cooled in water. It is not easy, even if possible at all, to
give as uniform a temperature by the ordinary processes of
heating, or to obtain the exact heat desired, and the quality
of the tool is not so easy of adjustment by any other method.
The Homberg alloy consists of equal parts of these
metals, and melts at about 254° F. (122° C.) ; it is silver white.
Krafft's alloy is composed of bismuth 63, lead 25, tin 12;
it melts at 220° F. (104° C.). Rose's alloy is a more common
one — 40 bismuth, 20 lead, 20 tin, or 50 bismuth, 20 lead, 30
tin. Another, Rose's alloy, is of 50 bismuth, 25 each lead
and tin, and melts at 205° F. (95° C.). According to
Ermann, this alloy fuses at 200° F. (94° C.) and expands from
a volume i,at the boiling point of water, to 1.0083 at 114° F.
(44° C.), contracts to 0.9913 at 148° F. (70° C.) and then ex-
pands to 1.0083 at the melting point.
Dobereiner's alloy, bismuth 46.6, tin 19.4, lead 34,
melts at 210° F. (99° C.).
Bismuth, Lead and Zinc in equal parts form an alloy
which melts in boiling water, according to Mackensie.
The melting points of fusible alloys, as determined by
Grehm, are as follows (see Art. 120):
ALLOYS.
SOFTENS
MELTS
Tin.
Lead.
at F.
atC.
at F.
atC.
2
2
365°
185°
372°
189°
2
6
372
189
383
195
2
7
377^
I9S
388
198
2
8
3954
202
406 to 410
216
118. Lead and Antimony uniter eadily and in all propor-
tions, forming alloys of intermediate character, of which the
most familiar is a u type metal," lead 34, antimony I. The
THE KALCHOIDS AND MISCELLANEOUS ALLOYS.
proportions vary with the size of type and with the character
of the work to be done. The alloy is ductile, quite strong,
hard enough to bear considerable use without wear or defor-
mation, and not so hard as to injure the paper. It fuses at a low
cherry-red heat, is not easily oxidized, and differs from lead
in most of its qualities simply by possessing greater hardness.
Keys of flutes and similar parts of instruments are made
of lead 2, antimony I. Shot for guns is often hardened with
antimony, and rifle bullets for large game are very frequently
similarly made, introducing very small quanties of either tin
or antimony or both. Low grade lead sold to shot-makers
often contains I or 2 per cent, antimony.
The alloy of lead with even a very small percentage of
antimony has been found, by Bischoff, to be subject to rapid
corrosion by even very pure water. As the salts of lead are
poisonous, any use of lead or of its alloys under conditions
favorable to the formation of solutions liable to enter into
drinking-water or food must be carefully avoided.
Riche reports the densities of alloys of lead and antimony
as below :
Density of the antimony 6.641
Density of the lead 12.364
THEORETICAL
DENSITY.
EXPERIMENTAL
DENSITY.
DIFFERENCE.
REMARKS.
Sb4 Pb . .
7 2^7
7 214
— .023
Sb3 Pb
7 l8^
7 ^61
— .024
Sb2 Pb
7 6*1
7.622
— .029
Sb Pb
8.271
8.233
— .038
Sb Pb2
9046
8 QQQ
— .047
Maximum dilatation.
Sb Pb3
Q ^IO
Q. 5O2
-.008
Sb Pb4
Q. 8lQ
V O^-*
Q.8l7
— .OO2
Sb Pb5
IO.O4O
IO.O4O
Nulle.
Sb Pb6
10. 206
IO.2II
+ .005
Sb Pb7
IO W(
IO 344
+ .ooq
Sb Pb8
IO 4^8
10.4^5
+ .017
Sb Pb9
10 521
IO ^4.1
+ .020
Sb Pbio
jo t;o2
TO 615
+ .023
Maximum contraction,
Sb Pbn
10.652
IO.673
+ .021
Sb Pbi2
IO 7O2
10 722
+ .020
Sb Pbis.
IO 74.6
10 764
+ .018
Sb Pbi4
10 785
IO.8O2
+ .017
198 MATERIALS OF ENGINEERING— NOX-FERROUS METALS.
The maximum of contraction corresponds to an atomic
alJoy SbPbIO, which has a rather simple composition, and
near the alloy SbPb2 is found the maximum of dilatation.
These alloys are crystalline. The alloys near SbPb2 crys-
tallize in quite large scales.
119. Tin and Antimony are easily alloyed, forming a sil-
ver or tin-white alloy, according to the proportion of tin,
usually brittle, and often sonorous when the antimony is
present in considerable amount ; its specific gravity is less
than the mean of the two constituents. Berzelius states that
the alloy of 3 parts tin to I of antimony can be worked hot,
although liable to crack along the edges. Berthier found the
alloy, tin 4, antimony I, very malleable and excellent for mak-
ing hollow ware and for white-metal cocks ; the mixture, tin
6, antimony i, is also used for such purposes and also for
various " pewter " (so-called) articles. This alloy takes a
good polish, which slowly disappears with long exposure to
the atmosphere. For domestic utensils an alloy of these metals
is often used, as free from danger of injuring food cooked or
kept in them ; the alloy is not usually affected by the acids
to which it is there exposed.
Chaudet investigated these alloys with considerable care.*
He found that containing equal parts of tin and antimony
harder than the latter, brittle and weak, and easily powdered.
Its fracture was white and fine grained, and its specific grav-
ity 6.8.
The alloy of tin 3, antimony i, had a specific gravity of
7.06, was somewhat malleable under the hammer, but very
liable to crack ; it had much less ductility than tin.
Nitric acid oxidizes these alloys without dissolving them,
and the oxide dissolves readily in hydrochloric acid, from
which the addition of water causes the precipitation of the
metals.
120. Tin and Lead alloy freely in all proportions, and
the two metals are often found associated in nature. The
addition of lead hardens tin, weakens it, alters its color from
* "Alliages Metalliques."
THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 199
white to gray, and changes its texture. When 3 parts tin
and i of lead are used, the hardest and strongest alloy is
produced ; its density is 8. An alloy of tin I, lead 2, is used
for a lead-solder and known as plumber's solder, and the
proportions are variable up to equal parts of each ; its density
is 9.4 to 9.6. Tin 2 or 3, lead I, produce alloys which are
very fusible, harder than either lead or tin, and which are
used as tinner's solders ; fluxed with resin, they are found
valuable in joining all kinds of tin-smith's work; the propor-
tion of the constituents is sometimes. I to I, and these alloys
are known as " soft-solder."
According to Watson the densities of these alloys are as
follows :
TIN. LEAD. S. G.
o
10
32
16
8
4
2
I
"•3
7.2
7-3
7.4
7-6
7-8
8.2
8.8
These alloys have a large number of applications in the
arts in making small instruments, apparatus and utensils ;
they are used in plating copper, in making organ-pipes, and
formerly in domestic utensils— for which, however, they are
unfitted by the solubility and the poisonous properties of the
lead, which are, however, greatly reduced by the presence of
the tin. The alloy containing 16 to 18 per cent, lead is not
sensibly attacked by vinegar or fruit acids. Alloys used in
plating copper contain from 40 to 50 per cent. lead. Of the
alloys of these two metals, that containing little or no ob-
servable amount of lead is used for domestic utensils ; 8 per
cent, lead gives a useful alloy for other dishes ; 20 per cent,
lead gives an alloy in considerable demand for ornamental
castings.
Messrs. Parkes and Martin have determined and tabu-
Jated the melting points of these alloys, as in the following
table :
200 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXVI.
MELTING POINTS OF TIN-LEAD ALLOYS.
PROPORTIONS.
MELTING POINTS.
PROPORTIONS.
MELTING POINTS.
Tin.
Lead.
Fahr.
Cent.
Tin.
Lead.
Fahr.
Cent.
4
4
372°
187°
4
28
527°
271°
6
4
536
167
4
30
530
274
8
4
340-
169
4
32
532
275
10
4
348
174
4
34
535
277
12
4
336
178
4
3i
538
278
14
4
362
182
4
38
540
279
16
4
367
184
4
40
542
281
18
4
372
1 88
4
42
544
282
20
4
378
190
4
44
546
283
22
4
380
191
4
46
548
284
24
4
382
iQ3
4
48
550
285
4
4
372
187
4
5o
55i
285
4
6
412
209
4
52
552
286
4
8
442
225
4
54
554
287
4
10
470
241
4
56
555
288
4
12
482
248
4
58
556
288
4
14
490
258
4
60
557
289
4
16
498
256
4
62
557
289
4
18
505
260
4
64
557
289
4
20
512
264
4
66
557
289
4
22
517
267
4
68
557
289
4
24
519
268
4
70
558
289
4
26
523
270
Parkes and Martin propose the following alloys for baths
used by cutlers and others in tempering and heating steel
articles :
TABLE XXVII.
BATHS FOR TEMPERING.
NO.
I
2
3
4
6
7
8
9
10
II
12
USE. '
LEAD.
TIN.
MELTING POINTS.
F.
c.
Lancets .
71
8
81
10
14
19
30
48
50
Oilb(
i
4
4
4
4
4
4
4
4
4
4
)iling.
420°
430
442
450
47°
490
509
530
550
558
600
612
213°
221
226
232
241
252
262
274
285
289
312
319
Other surgical instruments....
Razors
Pen-knives . .
Knives, scalpels etc
Chisels garden knives .
Hatches ... .
Swords watch-springs
Large springs, small saws
Hand saws . .
Articles of low temper
THE KA L CHOIDS A ND MIS CELL AN E OUS ALLOYS. 2O I
Tin and lead in equal parts make an alloy used for organ
pipes. It is cast in sheets on a table ; these sheets are
beaten smooth with a " planer," trimmed to size, rolled into
shape and soldered together at the abutting edges.
121. Tin and Zinc unite, in all proportions, readily and
uniformly, the quality varying less with variation of propor-
tions than in alloys generally, as may be seen by studying
the change of strength exhibited by the map and model
shown in the chapter on the ternary alloys. The introduction
of zinc increases the hardness of tin, and rather increases its
whiteness, when in small proportion ; in larger quantities it
reduces ductility perceptibly. The alloy is of granular, some-
times crystalline, structure, as revealed by fracture, and is
somewhat sonorous. With equal parts tin and zinc the alloy
is rather hard, moderately ductile, and of a very brilliant
lustre.
According to Koechl, the following are melting-points of
these alloys :
TABLE XXVIII.
FUSION OF TIN-ZINC ALLOYS.
TEMPERATURE OF FUSION.
Deg. Fahr.
Deg. Cent.
I
3
500-572
260-300
Pure metals.
2
4
572-662
300-350
" "
3
2
428-680
220-360
« «
i
I
472-662
250-350
• Commercial.
i
I
680-932
460-500
Pure metals.
The alloy of equal parts of tin and zinc is said by some
authorities to be nearly as strong as brass, to be much cheaper,
and a better anti-friction metal ; but it is necessary that the
zinc should be very pure. This alloy has been used in the
form of roofing sheets. The alloy tin 75, zinc 25, makes ex-
cellent metal patterns, the alloy flowing freely, running " sharp"
and expanding slightly when solidifying ; it should not be
overheated, and should be constantly stirred while pouring,
2O2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
to insure uniformity. This metal works easily, turns well in
the lathe, and does not clog the file.
122. Antimony, Bismuth, and Lead unite to form an alloy
which expands on cooling, and which is therefore used for
type-metal. Mackensie's alloy is antimony 16, bismuth 16,
lead 68. Stereotype plates of good quality may be made of
this composition.
123. Antimony, Tin, and Lead are alloyed in the pro-
portion of antimony 17, tin 13, lead 70, to form another Mac-
kensie metal for stereotype plates and other printers' work.
Sheets of this, or a similar alloy, are used in engraving music
for printing ; a composition reported by Berthier is antimony
5, tin 60, lead 35.
124. Antimony, Tin, and Zinc, in the proportions anti-
mony 12, tin 44, zinc 44, make an alloy considered excellent
for lining pump-barrels.
125. Antimony, Bismuth, Tin, and Lead, in the propor-
tions tin 76, bismuth 8, antimony 8, lead 8, form the " Queen's
Metal," which is one of the " pewter " alloys of greatest beauty
and durability.
126. Pewter and Britannia Metal.— Pewter has a wide
range of composition, from tin 20, copper I, to tin 2, copper
i. The alloy is often mixed with lead, of which the Pewterers'
Company in 1772* permitted enough to bring the density of
the pewter from {-ff £ to ff f £ that of tin. The best Britannia,
a metal of this class, is said to be tin 77, antimony 15, copper
7, zinc 2 ; the alloy is cast in flat ingots and rolled into sheets.
Britannia wares, made in Sheffield, are often composed of
3^ parts block tin, 28 parts antimony, 8 of copper, and 8 of
brass. The tin is melted and kept at a red heat while the
antimony, the copper, and the brass are successively added,
molten. The liquid alloy is ladled into the ingot moulds,
which are slab-shaped cast-iron boxes, and the slabs thus
made are subsequently rolled into sheets or recast into the
form desired, or into such shapes as may be easily modified
to the necessary extent. Spherical vessels are usually " spun
up " in halves, which are then united by soldering. The
* British Industries. Bevan, 1871.
THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 203
solder is any very fusible composition of this class, and is often
made of tin 75, lead 25. The fusibility of the metal is such
that it requires some dexterity and great care to prevent its
injury in the process of soldering. Britannia is easily shaped
by all the familiar processes ; it may be cast, rolled and ham-
mered, and cut in the lathe or by hand tools with equal
facility.
127. Iron and Manganese have a strong affinity. In
small proportions manganese confers whiteness upon iron,
and the alloy called " ferro-manganese " is considerably used
in making steels containing very little carbon; the carbide of
this alloy, known as " spiegeleisen," or simply " spiegel " in
the trade, is used in carburetting iron to produce steels
" higher " in carbon.
A small proportion of manganese renders iron less fusible,
and is said to increase its tenacity. Many of the ingot-irons
in the market, called " mild " or " low " steels, contain more
manganese than carbon and are very strong and ductile, and
make excellent material for use where great changes of tem-
perature are not met ; this alloy is not considered suitable
for springs, however. In large doses, manganese does not re-
duce the ductility and malleability of iron to the extent ob-
served with the introduction of carbon. Karsten found that
nearly 2 per cent, manganese improved iron. Mushet foi nd
that the alloy iron 71, manganese 29, was not magnetic, and
concluded that the maximum attainable in iron was 40 per
cent, manganese. As the percentage of manganese increases,
the alloy becomes whiter, harder, more infusible, and more
brittle if the manganese is present in considerable amount ;
it is more subject to oxidation also.
128. Platinum and Iridium alloy to form a composition,
according to Matthey,* which is homogeneous and is capa-
ble of being forged. Its density is 21.5 when of the com-
position, platinum 98.5, iridium 12.5 by mixture, and platinum
90, iridium 10 by analysis. The density of the iridium was
22.38. The coefficient of expansion was from o° to 16° C.
(32° to 41° F.), 0.0000254.
* Proc. Roval Society, 1878.
2O4 MATERIALS OF ENGINEERING— NON-FERROUS METALS
129. Spence's " Metal " is not, strictly speaking, a metal,
but is a compound obtained by dissolving metallic sulphides
in molten sulphur,* which is fo and capable of receiving into
solution nearly all known compounds of sulphur and the use,
ful metals. It was discovered by J. B. Spence in the year
1879. The solution, on cooling, solidifies, forming a homo-
geneous, tenacious mass of the specific gravity 3.37 to 3.7 at
o° C. (32° F.). According to Dr. Hodgkinson, when finely
powdered, it is acted upon slowly by concentrated HC1 and
NO2HO in the cold ; in large lumps, little or no action takes
place ; the expansion coefficient appears to be small. The
fracture is not conchoidal, but somewhat like that of cast
iron.
It is said to be exceedingly useful in the laboratory for
making the air-tight connections between glass tubes by
means of caoutchouc, and a water or mercury jacket, where
rigidity is no disadvantage ; the fusing point is so low that it
may be run into the outer tube on to the caoutchouc, which
it grips on cooling, like a vice, and makes it perfectly tight.
It melts at 320° F. (160° C.), expands on cooling, is claimed
to be capable of resisting well the disintegrating action of the
atmosphere, is attacked by but few acids and by them but
slowly, or by alkalies, and is insoluble in water, and may re-
ceive a high polish ; it makes clear, full castings, taking very
perfect impressions ; it is cheap and easily worked. It has
been used as a solder for gas-pipes, and as a joint-material in
place of lead.
* Jour. Society of Arts. London, 1879.
CHAPTER VII,
MANUFACTURE AND WORKING OF ALLOYS.
130. Alloys of General Application ; Brass Working.^
Of the alloys described in the preceding chapter but a few
are employed by the engineer in his professional work, and still
fewer are familiar and in common use. Of all the known
alloys, the bronzes and the brasses, the coin alloys and a few
compounds of tin, lead, zinc, antimony and bismuth, only,
are so well known as to be properly classed among the ma-
terials of constructive engineering. All the others are of use
only in a restricted range of application and for a few special
purposes.
The methods of preparation are practically the same for
all, and the " brass foundry " is usually resorted to in making
them all.
Brass work is divided into several branches, which, accord-
ing to Aitken, are :
1. Brass casting, or ordinary foundry work;
2. Bell and cabinet-ware casting;
3. Pot-metal and plumbing work;
4. Stamped brass-work;
5. Rolled brass ; wire-work; sheathing;
6. Tube making ;
7. Lamp making;
8. Gas fitting;
9. Naval brass-founding.
Several of these lines of work may often be carried on
together, but it is usual to combine those most nearly re-
lated— as those involving casting, those in which the metal
is rolled or wire-drawn, stamping, tube-making and brass
finishing.
2o6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Casting is described at length in Arts. 131-2, on the brass
foundry.
Sheet-rolling is a very important branch of brass-making,
employing a large number of work-people and sustaining a
host of minor trades.
The ingot brass for sheet-brass rolling is cast in broad,
shallow, iron ingot-moulds, or when larger masses are to be
used, in stone moulds, cut out of the solid block. They are well
oiled and powdered with charcoal before filling them.
The cast ingots of brass are called " strips," and are
rolled, cold, by several successive " passes " through heavy
rolls, with occasional annealing as they become hardened by
the operation of the rolling-mill. When the surface of the
sheet is found to be irregular and to contain spots of im-
purity, the hand-scraper, or a scraping machine, is employed
to remove them, and thus to prevent liability to cracking and
raggedness of surface or edges. When rolled nearly to
gauge, the sheet is " pickled," to remove the oxidized surface,
and is then passed through the finishing rolls, which are finely
polished and give the sheet its final finish. Muntz metals
can be rolled hot, and therefore much more cheaply than
other brass.
Wire-drawing is conducted as in the drawing of iron and
steel wire ; but the rods to be drawn are cut, by a slitting-
mill, from sheet-brass. Like iron wire, brass must be occa-
sionally annealed, in passing from wire-block to wire-block.
Stamping in dies can be practised with any of the soft
and ductile brasses, or other alloys. It is by this process that
a large proportion of the cheap brass ornaments are made, as
well as many parts of various utensils, as lamps, door-fixtures
and kitchen utensils. The die on the anvil is made of the
desired form, and the metal is "struck" into it by the blow
of a " drop-hammer " carrying a companion die, the drop
falling from one to five feet according to weight and power.
Heavy drops are always worked by steam power. The
" force," or die carried by the drop, is usually of soft metal ;
the die on the anvil is of steel. For fine and small in-
tricate work, several blows are struck. This kind of work
MANUFACTURE AND WORKING OF ALLOYS. 2O?
does not compare favorably with cast brass, or bronze, in
clearness and fineness of lines.
Brass Tubes are made by either of several methods.
Sheet-brass is rolled, over a form, into a tube, and the edges
soldered together, or they are rolled into cylindrical shape
and soldered. For exact sizing, a mandrel is placed within
the tube and on this it is rolled to gauge. Seamless tubes,
such as are used in steam boilers and elsewhere under pres-
sure, are made by rolling, or by drawing down cast cylinders
in a mill consisting of several sets of steel rolls.
Brass-finishing includes lacquering, bronzing, dipping and
burnishing and other methods of giving a surface finish,
described at the end of this chapter.
131. The Brass Foundry is usually an adjunct to large
manufacturing establishments. It is generally small, and the
moulding room and casting room are in one. A drying room,
or core-oven, is conveniently located at the moulding room
side ; it may be heated by either steam or by stoves, the for-
mer being the better plan. A cleaning room and, beyond it,
a finishing or dressing room, should be attached to the foun-
dry, and, for fine work, a lacquering room is also required.
The " patterns " are of wood or iron, as in iron founding,
or they may be of stucco and pipe-clay. Patterns for brass
castings must be larger than for iron, as shrinkage is one-half
greater, z>., T\th inch to the foot, or about 20 cm. per metre.
The <( shrink-rule" use^d for iron will not apply for brass-work.
The flasks, and all details of apparatus, tools, and work are
very similar to those used in an iron foundry, and the meth-
ods are the same in the main. Castings are cooled rapidly,
often with water, to soften and toughen them.
132. Melting and Casting. — In the melting of the ma-
terials in the making of alloys in the foundry, two general
methods of procedure are practised ; in the one, all the con-
stituents are fused at the same time in the same crucible or
melting pot ; in the other they are fused one after another in
a definite order, which is determined by their relative fusibility,
volatility, and liability to oxidation, or to absorb oxygen and
other gases. The first of these methods is, perhaps, the most
2O8 MATERIALS OF ENGINEERING—NON-FERROUS METALS.
common, but the second is by far the better; thus in making
the most common ternary alloys, those of copper, tin, and
zinc, the copper is best melted first, the tin should be next
introduced, and the zinc, which is volatile and oxidizable, is
added last. If lead is to be introduced into such an alloy, it
is found best to put it into the crucible last.
Other things being equal, the metals should be added in
the order of their non- volatility ; the next controlling quality
is infusibility ; the least fusible should generally be melted first.
The casting and cooling of the alloy is hardly less a mat-
ter of importance than the methods of fusion. Liquation is
very liable to occur in certain cases, as in many alloys of cop-
per with tin, and to prevent it the most prompt cooling pos-
sible is resorted to ; the use of 4< chills," or metal moulds, is
sometimes found essential to success. In these cases, it is not
advisable to pour the alloy " cold," as liquation may have al-
ready commenced ; they should be poured hot — " sharp," as
the term is often used in the foundry — and yet compelled to
chill quickly, if possible.
The apparatus of the foundry, in which alloys are mixed
and cast, consists of an air, or wind, furnace, sufficiently large
to receive the crucibles in which the metals are melted, or,
sometimes, when the masses handled are very large, a rever-
beratory " open hearth " furnace, which is preferably heated
with gas or liquid fuel ; of a collection of crucibles, which may
be iron melting-pots for lead and alloys which melt at a low
heat and have no affinity for iron, but which are usually of
clay, of graphite, or of graphite mixed with clay ; and utensils
for weighing and handling the metals, fuels, and crucibles. In
some cases platinum and silver crucibles are used, as .in lab-
oratory work, but these are rarely needed. The crucibles
should be carefully selected, since the cost of these vessels is
often an important item of the expense account.
In melting, the constituents of the charge being intro-
duced in the order decided to be, on the whole, best, the
liquid metal should be carefully stirred after each addition,
and in such a manner as to secure most complete intermixture
without liability to injure it by exposure to an oxidizing
MANUFACTURE AND WORKING OF ALLOYS. 2OQ
atmosphere. When the alloy is not homogeneous and sound,
it may sometimes be greatly improved by refusion. In mak-
ing large castings, the several metals to be alloyed are usually
melted separately and all finally poured together into a reser-
voir in which they are thoroughly mixed before " pouring the
casting." Where a reverberatory furnace is used, the process
may be conducted as in crucibles ; in this case, especial pre-
cautions must be observed to preserve a deoxidizing flame
within the furnace. When they are used in making bronzes,
great care is taken to keep the mass constantly stirred to pre-
vent liquation and the floating of the tin to the top.
The fuel used in the mint-furnace is generally coke, which
should be dense, hard, bright, and should ring when struck.
In laige establishments, and especially in melting bronzes,
the open-hearth reverberatory is very generally used. Bell
founders use a peculiar dome-topped furnace, melting at more
moderate heat.
In " pouring," the small castings are made first and the
heavier are poured with the cooler metal.
Sheet-brass is first cast in plates between heavy marble
blocks washed with loam and well dried, or, often in ingots.
They are rolled in heavy plate-mills and occasionally annealed
as they become hard and unmalleable in the -rolls.
In making brass-plates and sheet-brass, the surface is
pickled, after the sheet is reduced nearly to size, in order to
give it a clean surface, and then, when a finish is demanded,
it is given by a set of polished rolls.
Wire-brass is cast and rolled into plates, which are cut
into narrow strips in a "slitting-mill " by narrow interlocking
roll-collars. These strips are rolled to a conveniently small
size, and are then sent to the wire-mill to be finished in the
draw-plates.
133. Furnace Manipulation. — In filling the furnaces, the
crucibles are slowly heated to avoid danger of breaking; they
are at first set bottom upward. When well heated, they are
set mouth upward and charged with the broken copper. The
tin or zinc is heated at the mouth of the furnace and is
added gradually to the copper as the latter becomes fluid.
14
210 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The zinc is liable to volatilization, and is, therefore, when
introduced, plunged well below the surface of the molten
copper. The Author has sometimes had it wrapped in dry
paper or other protecting material to secure protection from
loss by volatilization and oxidation. Great care is needed
to prevent the introduction of cold and especially of damp
metal ; seriously dangerous explosions are sure to take place
if this should happen.
The fumes arising from the molten alloys when poured
are unhealthy, and a form of intermittent fever known as the
" brass ague " is often produced by them where proper pre-
cautions in handling and in securing ventilation are not
observed.
The brass-founder's furnace consists of a vertical cast-
iron cylinder or other casing — often a brick structure — lined
with fire-brick to a diameter of 10 to 15 inches. The flue is
led off at one side at the top, and the whole is covered with a
plate having an opening of sufficient size to permit the
crucible to enter and fitted with a cover plate. ; The grate is
usually composed of loose bars which can be easily and in-
dependently withdrawn or inserted.
Each furnace contains one crucible, and large castings are
only made where several furnaces are in use or where the
alloy can be melted in a reverberatory furnace. Tuyeres are
sometimes fitted for the purpose of increasing the rapidity of
melting, and the crucibles are then, when large castings are to
be made, emptied as fast as ready into a ladle which serves
as a collecting reservoir from which the mould is filled.
The fuel is usually either coke or charcoal.
134. The Preparation of the Alloys involves considerable
knowledge of the behavior of the mixture and its constituents
while fusing and while the alloy is being formed, and can
only be successful when the skill and judgment of an ex-
perienced founder aid in the work of melting and casting.
There are two methods of making alloys : the one is that of
weighing out the constituents in proper proportions and
mixing and melting all together ; the other is that of mixing
and melting the constituents successively and in an order
MAN UFA CTURE AND WORKING OF ALLO YS. 211
dependent upon the character of the metals and the alloy
made of them. The first is the usual method and is the least
troublesome and expensive ; but it does not usually give as
sound, uniform, and strong castings of the alloy as the second.
In the latter case, the metal of highest melting point is
usually first fused and the others are added in the order of
fusibility or volatility. The order of introduction into the
crucible or melting-pot has an appreciable effect on the quality
of the alloy.
After the alloy has been made and poured into the ingot,
or other mould, it may change in composition by the process
of separation or "liquation," to which reference is elsewhere
made, either by the denser metal settling out or by the
change due to formation of other definite alloys of greater
stability at various points in the mass, thus altering the com-
position of the metal all around those points. Thus in gun-
metal (bronze) the surface of fracture often has a variegated
color due to separation of the tin and the production of a
variable composition of alloy. This will be noted in the
description of the behavior of many alloys made by "the
Author. It will be seen that the rapid cooling secured by the
use of metal moulds is the best means of preventing this
liquation. Slow cooling, affording ample time for the separa-
tion and reconcentration of the constituents, and for the pro-
duction of crystals, permits, often, very serious loss of quality.
It will be noted that the best alloys are usually made most
successfully when the molten metal is poured " sharp," i. e.t
hot, and then rapidly cooled to the point of solidification.
The process of liquation is sometimes usefully applied, as
in the Pattinson process of separating the metals in argentif-
erous galena, or in cupriferous ores of lead.
The desired alloy is very rarely made of its essential con*
stituents only. A simple binary alloy of copper and tin is,
for example, rarely made in commercial work. Lead is often
added to give color, zinc to cheapen it or to flux it, and some-
times other metals to give special qualities. Statuary bronze
usually contains some lead and zinc to give it its peculiar
u patina"; bronze used in "hardware" and architectural
212 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
work, in bearings, etc., contains lead to give color and to make
it wear well ; brass is hardened greatly, and strengthened, by
the addition of one per cent, tin, or more, as in the " maxi-
mum alloys" discovered by the Author. In such cases, the
metal is added in small quantity to the mixture, after the
latter is in fusion and alloyed.
135. Minute Quantities of Alloy often greatly influence
the properties and quality of metals. Thus, it is stated * that
lead alloyed with 0.003 per cent, of antimony turns percep-
tibly freer than pure lead ; that an addition of 0.007 Per cent«
copper unfit leads for use in the manufacture of white lead ;
that gold containing 0.05 per cent, of lead exhibits greatly
decreased ductility ; that copper containing 0.5 per cent, iron
has but 40 per cent, of the conductivity of pure copper.
Nickel is too brittle to work ; but, alloyed with O.I per cent,
magnesium or 0.3 per cent, phosphorus, it can be rolled and
worked. Brittle steel is sometimes made tough and malle-
able by alloying it with 0.08 per cent, manganese or magne-
sium. A difference of o.oi per cent, in the amount of phos-
phorus present in the best Swedish irons can be plainly
observed by a change of malleability.
136. Art Castings in Bronze represent the most perfect
work known in the department of foundry work. It has been
practised from the earliest known and even pre-historic peri-
ods, and the analyses of art castings found in the Egyptian
tombs and in Nineveh prove that the composition then
adopted was substantially that of the statuary bronze, and
that of the art-work of to-day. The Greeks began to make
bronzes several hundred years before the Christian era, and
before the commencement of that era, had attained great skill
in the art. The statue of Apollo, at Rhodes, made by the
pupil of Lysippus, Chares, 330 B.C., was about 100 feet (30
metres) high, and after having been shaken down by an earth-
quake some 60 years later, lay over 900 years prostrate, and
was then carried away by a Jew who purchased it from the
Saracens, making a load, as it is said, for 900 camels. The
Chinese and Japanese first made use of bronze at some
* Der Techniker, 1883.
MA N UFA CTURE AND WORKING OF ALLO YS. 21$
unknown but very early date. The art was long lost in Europe,
but was revived in the i6th and i7th centuries, and now con-
stitutes an exceedingly important industry.
Art castings of large size are moulded and cast precisely
as other brass-founding is done; but great precaution is taken
in the selection of materials, in determining exactly the desired
proportions and in all the details of foundry practice and
manipulation. The usual mixtures are given elsewhere.
In making statuary, the model is first formed, and is then
lined cff by the founder in sections in such manner that each
will be likely to be easily moulded and will " draw " readily ;
plaster patterns are made of these sections separately, which
are used in obtaining metal copies, which latter are finally
joined together. Where the piece is to be cast whole also,
the mould must be often made in many parts, in order that
every section of the mould may be readily removed. In some
cases, an elastic mould is made within which a wax model is
formed, the latter being moulded in the sand in the usual
manner. For such work, a plaster cast is usually first made,
which is coated with any oily or glutinous substance which
will not allow moisture to be transferred, and will not permit
the adherence of the cope or mould, to be formed over it. By
covering the model with a thin coating of wax, an outer mould
can be constructed, and the inner and outer shapes may thus
be separated by a thin space which represents that to be
filled by the molten bronze, and determines the thickness of
the casting. This space is often filled with wax and the latter
is melted out when the mould is sent into the drying room or
oven. Properly made, the mould has smooth, perfect sur-
faces of the exact form to be reproduced, and the bronze,
when removed from it, is an exact reproduction of the model,
only requiring a small amount of work to make it marketable.
If the composition and the work are what is desired, the sur-
face of the casting is smooth, precise in form, sharp in out-
line, and of good color. Statues thus made acquire, with age,
a color or "patina" which distinguishes all good bronzes.
Statuary bronze, and bronze for art-work generally, should
have, when newly cast, a fresh, yellow-red color, and a fine
214 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
grain, should be easy to work with file or chisel, very fluid
when melted, taking the finest impressions of the mould, and
when exposed to the atmosphere in the finished casting, should
take the peculiar green patina characteristic of old bronze
statuary of good quality. These qualities are not usually ob-
tained in so high a degree in the copper-tin or copper-zinc
alloys, the common bronzes and brasses, as in alloys contain-
ing the three metals. According to Guettier, the best of these
alloys are :
COPPER. ZINC. TIN.
92 6 2
85 ii 5
65 32 3
It is very usual to add i or 2 per cent, of lead ; ancient
bronzes contain as much as 6 per cent. According to Pliny,
bronze was made by melting copper first, then adding 12^
per cent, of an alloy of equal parts tin and lead, known as
plumbum argentarium.
137. Stereotype Metal, of which a good quality is made
of 1 6 parts antimony, 17 parts tin, and 67 parts lead, is worked
thus:
The type is brushed over with a small quantity of black-
lead and oil, placed in a casting-frame, and a cast taken in
plaster of Paris. This cast is dried in a hot drying-oven
until absolutely free from all moisture, and is held in form,
meantime, by securing it to a flat cast-iron plate. The stereo-
type metal is cast upon the matrix thus produced, and the
plate thus obtained is planed up to a gauge and fitted to the
press, or mounted on wooden blocks of the right height to
work in the press. Damaged type are cut out and replaced
with perfect ones.
A later process is the following : * A sheet of tissue paper
covered with printing paper is placed upon a perfectly smooth
metal plate, and the two sheets are pasted together.
These sheets are laid over the type, beaten into their in-
terstices, covered with other sheets similarly beaten down, and
* Spon.
MANUFACTURE AND WORKING OF ALLOYS. 21$
this process is continued until the mass of paper forms a
matrix of satisfactory thickness and strength. Heavier paper,
as cartridge paper, is used for the last layers. This matrix is
dried carefully between surfaces which hold it in shape, is then
brushed over with French chalk or black lead, and laid in the
casting box, where the stereotype metal is cast over it and a
plate thus made.
138. German Silver is made by English founders of
small bells and similar articles of copper 57, zinc 19, nickel 19,
lead 3, tin-plate 2. The copper and nickel are fused together
first, the zinc added after their fusion, and the other metals
last. Commercial zinc containing lead is rarely pure enough
for the finer grades of this alloy which do not permit the in-
troduction of lead. It is difficult to obtain this alloy in
correct proportions and of good quality.
139. Babbitt's " Anti-attrition " Metal is usually riot cast
directly into the " brasses " to be lined with it. It is made
by melting separately 4 parts copper, 12 Banca tin, 8 regulus
of antimony, and adding 12 parts tin after fusion. The anti-
mony is added to the first portion of tin, and the copper is
introduced after taking the melting-pot away from the fire,
and before pouring into the mould.
The charge is kept from oxidation by a surface coating of
powdered charcoal. The " lining metal " consists of this
" hardening," fused with twice its weight of tin, thus making
3.7 parts copper, 7.4 parts antimony and 88.9 parts tin.
The bearing to be lined is cast with a shallow recess to
receive the Babbitt metal. The portion to be tinned is
washed with alcohol and powdered with sal ammoniac, and
those surfaces which are not to receive the lining metal are
to be covered with a clay wash. It is then warmed suffi-
ciently to volatilize a part of the sal ammoniac, and tinned.
The lining is next cast in between a former — which takes the
place of the journal — and the bearing.
Founders often prefer to melt the copper first in a plum-
bago crucible, then to dry the zinc carefully and immerse the
whole in the barely fluid copper.
A report of a committee of the American Master
2l6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Mechanics' Association, reporting on the use of Babbitt metal,
state that thirty-five replies to their circular gave the following
facts relating to the use of Babbitt metal : Four use gibs
with Babbitt ; four use the solid octagon brass without
Babbitt ; seven use octagon with Babbitt ; seven use half-
round solid brasses without Babbitt ; four use half round
brasses in three pieces with Babbitt, and one makes no re-
port of the use of Babbitt. All, with one exception, report
that the Babbitt metal should extend the entire length of the
journal and should be put on in strips ^ to \y2 inches
wide, at a point between the top and the front and back
points of the journal bearing ; one inserts it by drilling holes
in the brass and then filling in with the metal. The Com-
mittee have observed that, in engines of from thirty-two to
thirty-five tons weight, the half-round brass does not give as
good results as in lighter engines. Good results may be ob-
tained from a hexagon-shaped brass if properly fitted. The
Babbitt metal will wear until it is cut through into the cast-
iron. The recess in the top of the brass is of advantage also
as a reservoir for oil ; and as there is less bearing at that
point, the brass wears away and the shaft beds itself into the
brass, so that there is no lost motion or pounding between
the shaft and the brass. The Committee is of opinion that
the use of Babbitt metal is advisable.
140. Solders are alloys used in joining metallic surfaces,
and parts of apparatus or constructions, by fusing them upon
the surfaces of contact, and allowing them to cool, obtaining
a more or less firm and tenacious union. They have a wide
range of composition ; the " soft solders " are made of tin and
lead ; " hard solders " are usually made of brass ; and special
solders are composed of various alloys of copper, zinc, lead,
tin, bismuth, gold and silver. Haswell's table of solders is
given later.
In soldering copper, brass, or iron with soft solder, a
" soldering iron " is used to melt, and to apply the solder to
the work. This instrument consists of a copper head, shaped
somewhat like a machinist's hammer, the large end of which
is inserted longitudinally in the claw- shaped end of an iron
MANUFACTURE AND WORKING OF ALLOYS. 21?
holder, which is itself carried by a wooden handle ; it is
heated in a small charcoal-furnace, or " brazier," which is
especially constructed for the purpose.
A " soldering fluid," usually a solution of zinc in hydro-
chloric acid, is used to remove the oxide from the surfaces to
be joined and to give them a coating of zinc, to which the
solder will promptly adhere.
Soldering is often successfully performed by cleaning the
surfaces thoroughly, fitting them nicely together with a file,
if necessary, placing a piece of tin-foil between them, binding
them firmly together with " binding wire," and heating in
the flame of a lamp or a Bunsen burner, or in the fire, until
the tin melts and unites with both surfaces. Joints carefully
made may be united, in this way, so neatly as to be invisible.
When using the more fusible solders, as those containing
bismuth, a fire is seldom needed. When one joint has been
made with hard solder, it is not always safe to make another
near it with the same composition ; a softer solder should
then be used.
Soft solders are not malleable, and where this quality is
demanded, the solder is necessarily of the hard variety. An
excellent solder for such work is made with silver and brass
in equal parts.
Coin silver, in thin sheets, is an excellent solder for cop-
per, hard brass, and wrought iron. Cast iron cannot be readily
soldered, and the attempt is rarely made.
In making solders, great care is to be taken to secure uni-
formity of composition ; they are often granulated by pour-
ing from the crucible or ladle through a wet broom or from a
considerable height into water, or they are cast in ingots
and reduced to a powder by filing or by machinery. The silver
and the gold solders are usually rolled into sheets ; the soft
solders are generally sold in sticks, as is also pure tin ; those
which are rich in tin are distinguished by their peculiar " tin-
cry," which is destroyed by a very small admixture of other
metals. In making solders, as all other such alloys, the most
infusible metal is first melted, and the other constituents are
.added in the order of infusibility. Soft solders are very
218 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
fusible and are melted under tallow, and the hard solders are
prepared under a covering of powdered charcoal to prevent
oxidation.
Yellow brass, containing from 65 to 80 per cent, copper,
will be found useful at times in brazing wrought iron, mild
steel, and all the common brasses and bronzes containing less
than 10 per cent, tin or lead. Equal parts of copper and zinc
make a good solder for yellow brass and is known as " broom "
solder. Tin and lead are sometimes added, but probably
without advantage, the one making the solder hard, the other
weakening it. For brazing iron, yellow brass is excellent.
In using these solders, the surfaces to be brazed should
be well cleansed, sprinkled with borax, and bound tightly to-
gether with fine iron wire. A clay " dam " around the joint
is useful in confining the solder in place when melting. The
heating should be gradual and the temperature brought slowly
up to a red heat, occasionally adding borax, and, finally, the
heat should be more quickly raised until the solder melts and
fumes, when the piece is cooled.
Silver and yellow brass make good solders for steel, melting
at a moderately high heat and having considerable strength.
Both solder and flux should be used sparingly to secure good
work. Cast iron and alloys containing either tin or lead in
considerable quantities cannot be easily soldered.
The soldering fluid answers as a flux for soft solders ; borax
is used with the hard varieties, as it dissolves the oxides of
all metals thus treated, and leaves the clean metallic surface
which is essential to perfect union. Sal ammoniac is often
added to the soldering fluid when soft solders are used, and
resin is a common, and in some respects the best, flux for tin-
ner's work.
Platinum is soldered with gold, and German silver with a
solder of equal parts of silver, brass, and zinc.
The essentials of a good solder are that it shall have an affin-
ity for the metals to be united, should melt at a considerably
lower temperature, should be strong, tough, uniform in com-
position, and not readily oxidized. (See tables, pp. 221, 241.)
141. Standard Compositions are often adopted by en-
MANUFACTURE AND WORKING OF ALLOYS.
2I9
gineers for the various purposes to which they apply the
alloys. The tables hereafter presented are full of examples.
In further illustration, we have the following as the compo-
sitions adopted by the Paris, Lyons, and Mediterranean Rail-
way of France :
TABLE XXIX. .
STANDARD ALLOYS.
AT T OV
PROPORTIONS.
TJOpC
A-LLiU i •
Copper.
Tin.
Zinc.
Lead.
Ant.
U ol'O.
Gun- metal, i.
82
16
2
Bearings .
2.
84
14
2
,
. .
Valves, Screws, etc.
3-
9°
8
2
,
Cocks, Whistles, etc.
Brass, i.
70
, .
30
,
. .
Tubes.
2.
67
. .
33
t
. .
Stuffing-boxes, etc.
3-
65
. .
35
. .
Handles, Latches.
4-
63
.
37
t
Plates, Washers.
White metal.
5
7i
24
Bearings.
Packing "
14
76
10
Stuffing-boxes.
Solder.
45
55
For tin plate.
40
60
• •
" zinc "
The useful alloys are, as already seen, exceedingly
numerous, and are of extraordinary variety in appearance and
physical qualities. They are applied to an almost equally
wide range of uses. The following very complete lists will
give an idea of their number, quality and applications.*
* Chas. Haswell; Pocket-book, 1882. C. Bischoff: Das Kupfer und seine
Legirungen ; Berlin, 1865. P. A. Bolley: Recherches Chimiques ; Paris, 1869.
A. Herve: Alliages Metalliques, Manuel- Roret ; Paris, N.D.
22O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXX.
ALLOYS AND COMPOSITIONS. — HASWELL.
M
o
5
g"
NICKEL.
LEAD.
ANTIMONY.
1
s
SILVER.
COBALT OF
IRON.
IRON.
ARSENIC.
Argentan
55-
24.
2.5
Argentiferous alloy
Babbitt's metal
Ro "
25.
" hard
79-3
92.2
80
6-4
14.3
7.8
" mathematical instruments.
" Pinchbeck
" red tombac
88.8
" rolled . . .
74-3
22.3
3-4
" tutenag
" very tenacious
880
VI
8.3
" wheels, valves.
10.
" white
80
67.
" yellow, fine
66
Britannia metal
u when fused add. . .
25.
25.
Bronze, red
87
" red
86.
" yellow
67.2
31.2
T 6
" cymbals. . ....
80
2O.
" gun metal large
" small
7-
" metals
" statuary
1.7
f\
o (8
Chinese white copper.
2 6
«*6
Church bells
80.
69.
72.
5-6
10. 1
*
Clock bells
1.5
Clocks, musical bells
87 5
German silver
33-3
33-4
31 1
" 6
" line
ffr'fi
18 4
House bells
&
87 <;
" hard
77-4
7-
15-6
Metal that expands in cooling
75.
16.7
8.3
Muntz metal
60.
40.
86
80
80
'(>"
....
Speculum '
66.
22.
2.
66*6
29.
Temper *
Type and stereotype plates
33-4
....
66.6
28 4
....
69.
;;:;
xs:5
...
...
••!
. " hard
Oreide
69.8
73-
12.3
(Mag
1 Sal-a
nesia. .
mmon
... 4
lac 2
IS
>eai
Juicl
n of
dime
tarta
r6.«
* * *
* For adding small quantities of copper.
MANUFACTURE AND WORKING OF ALLOYS.
TABLE XXX.— Continued.
SOLDERS.
221
COPPER.
,
LEAD.
n
R
5>
I
j
CALCIMINE.
j
Tin
58
16
16
10
" course, melts at 500° . . ,
67
67
33
Spelter, soft
so
" hard....
67
33
*
Lead...
00
67
"
Steel
82
5°
SO
*
Fine brass
AJ
6
00
45
U U
Gold
**
**
80
u hard...
66
"
* *
"
" soft.
66
80
Silver, hard....
* *
67
"
soft
*
Pewter
40
20
Jron
66
"*
Copper
53
47
* *
* *
FUSIBLE COMPOUNDS.
COMPOUNDS.
ZINC.
TIN.
LEAD.
BISMUTH.
CADMIUM.
2S
Fusing at less than 200°
33-3
33-3
33-4
••
Fusing at 150° to 160°
12
25
CO
13
142. Special Recipes. — The best bronze compositions for
use in engineering are, according to Guettier,* the following:
For pumps, bolts and similar pieces :
Copper. 88 I Copper 90
Tin 12 I Tin 10
100
100
The latter is the softer of the two. Often from one to
four per cent, of zinc is added, as already stated.
* Guide Pratique ; Paris, 1865.
222 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
For eccentric-straps and connecting-rod bearings :
Copper 83 84 83 84 82 85.25
Tin 15 14 15 14 16 12.75
Zinc 2 2 1.5 1.5 2 2
Lead .. 0.5 0.5 ..
100 100 100,0 100.0 100 100.00
The addition of lead and increase of copper gives softe!
alloys. Lead is often used more freely than above.
Locomotive driving-axle bearings :
Copper 74 80 85.25 86 89
Tin 9.5 18 12.75 14 8
Zinc , 9.5 2 2.00 .. 3
Lead 7 .. ....
100.0 IOO 100.00 100 100
The Author prefers gun-bronze to either of the above.
For Locomotive Slide Valves —
Copper phosphide 3.50
Copper 77.85
Tin ii.oo
Zinc 7.65
100.00
Connecting-Rod Brasses —
Copper phosphide 3.5
Copper 74.5
Tin II. o
Zinc n. o
IOO.O
Axle-boxes —
No. i. No. 2.
Copper phosphide 2.5 1.5
Copper 72.5 73-5
Tin 8.0 8.0
Zinc 17.0 19.0
100.0 100.0
MANUFACTURE AND WORKING OF ALLOYS. 22$
Parts demanding greater strength —
Copper phosphide 3.5
Copper , 85.5
Tin 8.0
Zinc 3.0
IOO.O
Zinc is here added to the bronze to aid in securing that
homogeneousness which is essentially the result of the ad-
dition of phosphorus.
For pistons (rarely needed) : copper, 89.75 ; tin, 2.25 ;
zinc, 8.
For car and locomotive axle bearings :
Copper 80 79 86 89
Tin 18 18 14 2.5
Zinc 2 2.5 .. 8.5
Lead 0.5
IOO IOO.O IOO IOO.O
For ordinary stationary machine journal-bearings: copper,
82 ; tin, 18.
For whistles of locomotives and bells :
Copper 80 81 78 79 78 71
Tin 18 17 20 23 22 26
Antimony 222 Zinc 6 .. Zinc 1.8
Iron io2
IOO IOO IOO IOO IOO IOO.O
The last is the alloy of the famous " silver-bell" of Rouen.
For pump-buckets, valves and cocks :
Copper 88 88 86.8
Tin 10 10 12.4
Zinc 1.75 2 0.8
Lead 0.25
IOO.OO IOO IOO.O
For hammers (for use on finished work) : copper, 98 ; tin, 2.
This alloy will forge like copper; it may be hardened by
adding more tin.
224 MATERIALS OF ENGINEERING-NON-FERROUS METALS.
For wagon axle bearings :
Copper 78
Tin. . . 20
Zinc.
Copper 25
Cast-iron 70
Tin.. «
ioo ioo
The best brasses may be taken, for general purposes, as
accepted by good makers, as follows:
For turned work :
Copper 61.6 66.5 74.5 79.5
Zinc 35.3 33.0 25.0 20
Tin 0.5 0.5 0.5 0.5
Lead 25
IOO.O IOO.O IOO.O IOO.O
The richer colors are given by the higher proportions of
copper. The official recipe for work in French dock-yards is :
Copper 65.80 76.0 85
Zinc 31.80 24.0 15
Tin 0.25
Lead 2.60 0.5 I
100.45 100.5 ioi
The hardest compositions are used for the smallest pieces.
These are used in the ornamentation of engines, for brass
straps, for hinges, and for pulley-sheaves.
Cheap alloys for bearings have been made of the follow-
ing wide range of composition :
Copper 56 5.5 58
Tin 28 19.5 28
Zinc 16 80.0 14
IOO IOO.O IOO
The first — Fenton's alloy — is said to wear well, not to be
specially liable to heating, and to be very durable. The last
— Margraff's alloy — is of similar quality. The second com-
position is much cheaper and lighter, and takes the place of
the white alloys used in bearings.
MANUFACTURE AND WORKING OF ALLOYS. 22$
Other white metals for similar uses are :
Copper 419!
Tin 96 50 73 50
Antimony 8 5 18 5
108 56 100 56
The first is used for common bearings; the latter for
small bearings carrying light loads. Still other alloys are :
Tin .. 18.0
Lead 32 85 4.5
Zinc 18 .. 75.0
Antimony..... 50 15 2.5
loo 100 100.0
The following are British (Woolwich) official recipes :
Copper 20 6 7 8 IO
Tin 2 I i I I
Zinc I ....
23 7 8 9 II
which are used as hard as metals are desired.
Kingston's metal, formerly much used for bearings, is
made by melting 9 parts copper with 24 parts tin, remelting,
and adding 108 parts tin, and finally 9 parts of mercury.
An alloy of 90 per cent, tin, 8 per cent, antimony, and 2
per cent, copper has been found excellent for crank and con-
necting-rod bearings on the Moscow and Nishni Railroad of
Russia. On the Kursk-Charcow-Asow Railroad an alloy of
78.5 per cent, tin, 11.5 antimony, and 10 copper is considered
very superior for pivots of all kinds, slide valves, eccentrics,
stuffing-boxes, etc. The Swiss Nordostbahn Company, in
ordering locomotives recently, required the following prepa-
ration as a composition for axle journals: 10 parts of anti-
mony added to 10 parts of melted copper, with 80 parts
of tin added, and the alloy run into bars, to be remelted
for use.
Bronze for bearings of axles, as made for the Great West-
ern Railway of Great Britain, has been given the following
15
226 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
composition : copper, 22 ; tin, 67 ; antimony, 1 1. French rail-
ways have used copper, 82; tin, 18 ; and Italian roads have
used an alloy of tin, 38 ; antimony, 25 ; and lead, 37, for a
lining metal. The Perkins alloy for piston rings consists of
copper 75, tin 25, and is used in steam engines worked at
very high pressure without lubrication.
143. A Classified Table of the Alloys has been compiled,
as follows, by Bolley,* from the works of BischofI f and other
authorities, which presents the most complete compendium
of the compositions used by the engineer and in the trades,
known to the Author. This table is here given, omitting the
alloys of the " precious " metals.
TABLE XXXI.
CLASSIFIED LISTS OF ALLOYS.
Alloys of Copper.
BRASS.
RED BRASS.
COPPER.
ZINC.
Q^.6
6.4
92.5
7-5
QO.O
IO.O
«< («
85.5
14.5
Tournay alloy for ornaments
82.54
f
17.40
English " " "
86.38
13.62
87 o
13 .0
Mannheim gold o 62 per cent tin and
V J .w
80 4.J.
9. 14
Q7.O
2.O
Arsenic, I.O
71 .5
28.5
Arcet tombac gilded .
82.3
17.7 '
85.3
14.7
Red " "
02. 0
8.0
«« " Vienna
07.8
2.2
99- *5
0.85
« « «
84.21
ic. 70
Bronze powder
84.0
16.0
84.6
15-4
«« «« (" gold ") Vienna
77. Q
22.1
* Recherches Chimiques. Paris, 1869.
\ Das Kupfer und seine Legirungen. Berlin, 1865.
MANUFACTURE AND WORKING OF ALLOYS.
TABLE XXXI.— Continued.
YELLOW BRASS.
227
COPPER.
ZINC.
Malleable brass
70. i
2Q Q
" " Liidenscheid
72. 73
27. 27
72.O
28.O
66 6
•3-7 A
Bobierre " Muntz metal
74.62
2C ^8
" " low grade ,
CQ. e
4.O $
»V*D
6O.O
^8.2
Iron, I . 8
6c A
^4 6
" " low grade •
6q *
q2 «;
Lead 2 o
64. 2
a-2 i
Lead and tin* 2.9
" ductile (Storer)
£4.0
46.O
6^ . 24
34.76
Malleable and ductile brass
60 26
1Q 74
« « 1 1
66 o
•74. o
Kessler's " "
H8.q
41. 7
66.7
a 7. q
7c . 7
24.^
u «
60.8
3Q.2
Mosaic gold •• «...»
6n ^
04 7
6l 2s?
•28 7C
aa. 74
66.64
WHITE METAL.
COPPER.
ZINC.
CC.o
" Platine "
43 o
1:7 o
Button alloy Liidenscheid . . .
20 o
Mallett " preservative of iron
25 4
74.6
BRONZE-LIKE BR,
Tombac Alloys
\ss.
COPPER.
ZINC.
TIN.
80.0
I7.O
3-0
Golden bronze .
80.07
9.06
O.O7
"VV/
82.0
17.5
O.5
228 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXXL— Continued.
Statuary Bronze.
•
COPPER.
u
g
N
S5
P
Q
55
O
g
NICKEL.
ANTIMONY.
The Shepherd, Potsdam Palace.
88 68
I 28
Q 2O
O 77
Bacchus Potsdam Palace .
80 ^j.
i 6^
7 eo
I 21
o 18
80 78
J..UJ
S-JC
6 16
1 33
O.27
Augsburg bronze
« a
8943
QJ. 7J.
Oe A
8.17
i 64
1.05
O 2-1
0-34
O.ig
o 71
o 84
Munich " . .
VH- /^t
77 O^
IQ 12
O Ql
2 2Q
O. 12
O.4^
92 88
O.dd.
4. l8
2 31
O.I5
Keller's Louis XIV
5C-J
I 7O
I 37
Henry IV Paris
fin 62
57O
o 48
./u
3OO
2 OO
/:>.u<j
80 20
o 50
IO 2O
O IO
For Small Objects to be Gilded. Arcet.
Copper 63 . 7 to 72 .43
Zinc 33.55 to 22. 75
Tin 2- 50 to 1.87
Lead 0.25 to 2.97
Leaf and Wire Brass.
COPPER.
ZINC.
TIN.
LEAD.
7O 2Q
20 ^6
Q 28
0. 17
71. 80
11 6^
** *»
O.85
6j.. 6O
•a -I.7O
I.4O
O.2O
Aix la Chapelle leaf
64 80
32 80
2.OO
O.4O
White Alloys for Buttons.
COPPER.
ZINC.
TIN.
LEAD.
Bristol Alloy
C7.Q
36.8
5.3
6l 12
^6 ii
2.77
63.88
'lO.cc
K.tS
<« «
6^ 01
•ic 6l
I OQ
48 50
31- 32
6.06
12.12
u Gold " . .
eg 71
a -2 o^
C . CQ
2.75
MANUFACTURE AND WORKING OF ALLOYS.
229
TABLE XXXI.— Continued.
Pewter.
COPPER.
ZINC.
TIN.
LEAD.
Berthier's alloy
71 .Q
24. Q
1.2
2.O
Alloy to be cast and worked.
« tt « « «
" " " " gilt....
« « (( <( «
64.2
61.6
63.7
64.5
60.66
34-6
35-3
33-5
32-4
36.88
0.2
0.6
2.5
0.2
1.35
2.0
2-5
0.3
2.9
O.74
«< <( «
66.06
•IT 4.6
I 43
0.88
tJruns, Oreide, S. G. 8.79...
Oker brass (Harz)
68.21
64 24
3I-52
37.27
0.48
O. 5Q
0.24
O.I2
Sheathing Nails.
COPPER. ZINC.
For ships 63.60 25.00
Solder (Strong).
TIN.
2.60
LEAD.
8.80
COPPER.
ZINC.
TIN.
LEAD.
Yellow, hard solder
e-i.ao
A'i. IO
I. 3O
O.3O
Nearly white, soft
44.OO
4Q.QO
•3.-2O
1. 20
White, very soft
1:7.44
27.08
14.58
ALLOYS FOR BEARINGS AND CASTINGS.
Copper- Tin-Zinc.
COPPER.
ZINC.
TIN.
Locomotive and Railroad work :
Eccentric strap (Dutch)
85.21?
2.OO
12. 75
Piston ring's (Seraing)
80.00
Q.OO
2.OO
82.00
8.00
IO.OO
hard (G. B )
87.05
5.07
7.88
78.00
2.OO
20.00
« <« i < «
Q7.2O
2. SO
" " Lafond's alloys
80.00
2.OO
18.00
Whistles (dull) " "
81.00
2.OO
17.00
Hard bearings " "
82.00
2.OO
16.00
Castings for pumps, etc. , Lafond's alloys . .
Eccentric straps "
88.00
84.00
QO.2O
2.OO
2.00
6.30
10.00
14.00
3.50
Pistons and rods . . .
74 IO
22. 2O
3.70
Parts to be cast upon iron . ...
78 7O
15 .OO
6.30
88.80
2.7O
8.50
Weights philosophical apparatus
90 oo
2.OO
8.00
Mathematical instruments standards . .
82. 10
% . IO
12.80
230 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
TABLE XXXI.— Continued.
COPPER.
ZINC.
TIN.
ANT.
LEAD.
Small fine coatings .... . .
70 10
7.80
iq 10
8-3.7O
9. ^o
7.OO
Medals
Q7.OO
2.OO
I.OO
Coins (Fr )
QC OO
\ .OO
4.OO
yo -W
87.OO
12. OO
I.OO
Steam whistles > . .
80 oo
18 oo
2 OO
82.74
8.2-3
9 O1
8*
e
7
a
" " (hard) . .
QO
a
4.
a
COPPER.
ZINC.
TIN.
LEAD.
ANT.
Machinery brass
71 jo
8 QO
9. ^O
7. 10
Bearings of engines ..
7Q.OO
5.OO
8.00
8.00
Pistons " "
84 oo
8 4O
2.QO
47O
Parts at high temperature • • .
QO 7O
c . ao
2.7O
1.30
Golden colored
74.00
IO.OO
I.OO
15.00
harder
70.00
IO.OO
IO.OO
IO.OO
Parts under heavy friction (Laf ond) . . .
83.00
63 60
1.50
24 60
15.00
2 60
0.50
8 70
Chinese white metal .
72. CO
14^0
4. 7O
18 50
Bearings and valves, etc
80.00
16.00
2.OO
2.0O
Alloys Containing Iron.
COPPER.
ZINC.
TIN.
LEAD.
IRON.
Bearings of locomotives (G B )
89 oo
7.8O
2.4O
O.8O
" <' «« (German)
81 17
15 2O
14 60
O QO
«' " " durable
7-3. co
Q- 5O
9.5O
7.5O
O.5O
Piston-rings of " (Stephenson) .
84.00
8.30
2.90
4-30
0.4O
Alloys Principally Copper and Tin.
COPPER.
TIN.
ZINC.
LEAD.
NICKEL.
IRON.
Bell metal
78 to 80
22 to 2O
60 oo
40 oo
7C 2O
24 80
of Reichenha1' S G 8 7
80 oo
20 oo
metal white silvery
78 oo
22 OO
7C to 7"3
oc to 27
< «<
oe OO
5OO
< <<
71 4^
JD 'uw
26 40
2 17
" ' Darmstadt
7"3 Q4
21 67
I.IQ
2. II
O.I7
«< < «
72 C2
•**•"/
21 OO
2.14
2.66
O.O5
MANUFACTURE AND WORKING OF ALLOYS.
231
TABLE XXXI.— Continued.
Bearings: Copper, Tin, Lead.
COPPER.
TIN.
LEAD.*
87.50
89.20
82.20
79.70
79.70
77.00
77.00
69.00
65.00
48.00
12.50
IO.OO
IO.OO
10.00
10.00
10.50
8.00
10.00
5.00
«• «• "B"
7.00
9.50
9.60
12.50
15.00
21 .OO
3O.OO
47.00
" " c "
" Phosphor " bronze (standard) . .'. .
•• "B"
« « "B"
« <« « (3 "
* Wear increases with lead.— Dr. Dudley.
Mirrors.
COPPER.
£
P
y
N
z
jj
SILVER.
NICKEL.
"
1
Composition Ciu Sn
68.21
<5I.7O
Mudsre's alloy . . .
68 82
a[ 18
Laderig's alloy (excellent)
60 oo
28.7O
Good lustre (yellowish) .
50 oo
28 60
2I.4O
Edward's alloy
63 30
32.2O
1. 60
Cooper's alloy . . . .
69. 80
1:7 go
25.10
27 3O
2.60
3.60
2.40
1. 20
IO.8O
....
....
Richardson's alloy
6^.30
3O.OO
O,7O
2.OO
2 OO
Sollit's ' '
64 60
31 3O
4 10
Chinese mirrors (Eisner)
80 80
O IO
8 40
Machinery Bronze.
COPPER.
TIN.
08. od
1.96
Q4.. IO
^ .QO
QI . 3O
8. 70
qo.oo
IO.OO
Seraing " " "
86 oo
14.00
84.00
16.00
83.30
16.70
232 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXXI.— Continued.
GERMAN SILVER, ETC.
Nickel Alloy.
COPPER.
NICKEL.
82 88
18 15
Belgian 4<
7c .00
25 oo
U. S. Alloys in recent coinage :
8*
12
Recent coinage
•ye
2<
/.)
O
German Silver.
COPPER.
ZINC.
NICKEL.
55-oo
50.66
26.30
43.80
45.70
59-30
55-20
51.60
45-70
52.00
59-oo
63.00
50.00
50.00
58.30
50.00
55-6o
60.00
55-50
62.50
50.00
59-0°
25.00
I9-3I
36.80
40.60
39-9°
25.90
24.10
22.60
20.00
26.00
30.00
31.00
31-30
30.00
25.00
25.00
22.20
2O.OO
39-oo
31.20
18.80
30.00
20.00
I3-I8
36.80
15.60
17.40
14.80
2O.7O
25.80
3I.30
22.00
11.00
6.00
18.70
20.00
16.70
25.OO
22.20
2O.OO
5.50
6.30
31.20
IO.OO
\Vagner's " . . . .
Chinese alloy (Keferstein)
" tutenag, amber-colored, ha
Sheffield alloys :
rd
Silver white . .
Electrum, bluish
Hard alloy can be worked cole
Berlin alloys (Schubarth) :
Richest ,
1
Medium . ...
Lowest
*' ' (Chaval)
Austrian a loy, table-ware (Gersdor
« «( «
malleable
Fricke's bluish-yellow, hard
pale " ducti
silvery hard . .
fin
le
harder
Copper, Tin, Nickel.
COPPER. TIN.
NICKEL.
For castings
52.50 28.80
50.00 25.00
17.70
25-50
MANUFACTURE AND WORKING OF ALLOYS.
233
TABLE XXXI.— Continued.
ALLOYS LARGELY GERMAN SILVER.
COPPER.
ZINC.
NICKEL.
IRON.
COBALT.
Chinese Packfong S G. 8.432 . .
4O 4O
2C, .40
qi .60
2 60
White alloy, hard and brittle
48.80
24.4O
24 4O
2.4O
ca .00
27. OO
22 OO
2.OO
Parisian " Maillechort." S. G., 7.18 .. .
Sheffield alloy (Ger Silver)
65.40
58 20
13.40
2C CQ
16.80
T<5 OO
3-40
3OO
English " " "
60 oo
17 .80
18 80
o 4O
57 OO
2C .OO
m .00
•3.OO
ALLOYS CONTAINING LITTLE COPPER.
Alloys Rich in Tin.
COPPER.
TIN.
ANTIMONY.
\Vestphalian alloy
7 OO
82 oo
II OO
Magdeburg-Halberstadt alloy
II OO
74 OO
15 oo
«? OO
8«; oo
IO.OO
Antifriction alloy (Karmarsch) . .
37O
88 89
7 41
< < >
6 2s,
81 25
12 5O
< «
Q 76
7O T\
IQ «?I
< (i
21 .44
71 .41
7 14.
' (English)
971;
7O 77
IO ^2
7 80
76 7O
IE en
< K
2 OO
72 OO
26 oo
2.OO
QO.OO
8.00
Alloys Rich in Zinc.
COPPER.
TIN.
ZINC.
7.00
21 .OO
72.OO
Rolls for print-works ...
c OO
TC 8O
78 7O
4.20
20. 7O
66.50
COPPER.
TIN.
ZINC.
ANTIM,
Fenton's antifriction alloy • . ......
c eo
14. "^O
8o.OO
<» « «
Bearing metal (Manchester)
5-50
* 60
17 47
80.00
76 14
14.50
" " English
7 4O
14. QO
67.7O
" (Chemnitz)
5-00
8.50
10.00
234 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
TABLE XXXI.- Continued.
Alloys Principally Iron.
COPPER. TIN. ANTIM. IRON.
Hartshorn's alloy 8.35 1.38 1.38 88.89
French antifriction alloy . 25.00 5.00 .... 70.00
Alloy Largely Lead.
COPPER. LEAD. ANTIM.
Bearings for railway work 8.00 80.00 12.00
Alloy of Zinc and Lead, etc.
COPPER. TIN. ZINC. LEAD.
Soft metal ., 3.00 15.00 40.00 42.00
Alloy Principally Tin and Antimony.
COPPER. TIN. ANTIM.
White alloy 22.00 33.30 44. 50
BRITANNIA METAL.
Alloys Principally Tin.
COPPER.
TIN.
ANTIMONY.
q.oo
9I.OO
For castings (Baumgartel)
I 80
Sl.QO
16. 30
4.00
72.OO
24.00
Birmingham ' ' (sheet) .
I 5O
00.60
7 80
" " (cast)
O OQ
QO. 71
Q 2O
2 80
77.80
IQ-4O
ANTIMONY.
I
fc
h
i
N
BISMUTH.
LEAD.
Hard spelter . .
7 ^O
I OO
QO OO
Alger's alloy white sonorous
I .OO
e oo
Q4 OO
Beckmann's blue bronze
O QT
o 16
QO Q-7
Alger's alloy, hard, white, sonorous.
« « « u «
White metal
«.y*
2.IO
2.40
Q OO
\)J- VJ
97-30
97.00
67 *7O
24 3O
0.60
O.6O
For tinning iron
c 10
76 QO
IO 3O
7. 7O
Common spelter
4.4O
82.30
I . ^O
II.8O
Pewter
5 7O
81 20
I 60
II. 5O
6 on
3 jn
qo 10
o 50
" (Koller)
10 40
I OO
8c 70
2 QO
Pewter (leaf)
7 60
1. 80
80. 30
I. 80
« «
I. 7O
6.80
vy*jv
84.70
6.80
MANUFACTURE AND WORKING OF ALLOYS
TABLE XXX I. — Continued.
235
COPPER.
TIN.
ANTIM.
ZINC.
BISMUTH.
Britannia (Karmarsch) . . . .
" fine (Wagner) . . .
Pewter, often of
3-6o
0.81
i. 60
85.00
85-64
83.30
5-00
9.66
6.60
1.40
3.06
6.60
5-00
0.83
1. 60
Alloys Principally Zinc.
COPPER.
TIN.
ZINC.
LEAD.
Hamilton's alloy
•2 CQ
93 40
•2 IO
" (loss 3 per cent. Zn) .
3.60
OH. 2O
Heine's "
I I dO
I A.O
84 30
2 QO
" (loss 3 per cent. Zn) .
11.80
1.50
83.80
2.90
Alloys Principally Tin and Zinc.
No. i
No. 2 3 . oo
COPPER. TIN.
2.25 64.00
48.00
ZINC.
33-50
48 oo
IRON.
1-25
1. 00
Alloy Principally Antimony.
COPPER. TIN. ZINC. ANTIM.
White alloy, brittle, for castings .. 10.00 20.00 6.00 64.00
COPPER. LEAD.
Best.. 4.62 57.8o
Type Metal.
ANTIM. TIN. NICKEL. COBALT. BISMUTH.
17.34 11.56 4.62 2.90 1.16
ZINC. TIN. LEAD. COPPER.
Ehrhardt's 89.00 4.00 3.00 4.00
" 93-00 3.00 3.OO 2.OO
ALLOYS FREE FROM COPPER.
Tin and Zinc.
Imitation silver leaf . .
Type metal (Johnson)
TIN.
I. oo
59
ZINC.
II
33
236 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXXI.— Continued.
Tin and Lead,
TIN.
LEAD.
Solder I i
" weak 2 i
" hard and strong I 2
Tin and Antimony.
TIN. ANTIM.
Britannia 9 i
Antifriction metal (Karmarsch) 3-7 I
Type (Johnson) 75
Mercury and Tin.
TIN. MERCURY.
Amalgam for mirrors 70 3°
" " curved mirrors 4 i
Lead and Antimony.
LEAD. ANTIM.
Type metal 16 i
«' «• 4 I
, Lead and Arsenic.
LEAD. ARSENIC.
Shot metal 100 0.4-3.0
Bismuth and Mercury.
BISMUTH. MERCURY.
Amalgam for glass globes 80 20
TRIPLE ALLOYS.
Tin, Lead, and Bismuth.
TIN. LEAD. BISMUTH.
Newton's fusible metal 3 5
Rose's " " i i 2
Solder i-4 1-4
Printing rolls
Perrotine's alloy I J
Antimony, Lead, and Zinc.
ANTIM. LEAD. ZINC.
Lafond's alloy for bearings 50 30 20
MANUFACTURE AND WORKING OF ALLOYS.
TABLE XXXI.— Continued.
Tin, ZinC) and Mercury.
TIN. ZINC. MERCURY.
Kienmeyer's electrical amalgam I I 2
Singer's " " I 2 3-5-6
OTHER ALLOYS.
Tin, Lead, Bismuth, and Mercury.
TIN. LEAD. BIS. MER.
Amalgam for curved mirrors I I I 9
" " anatomical preparations. 7 4 12 2O
•
Tin, Lead, Bismuth, and Antimony.
TIN. LEAD. BIS. ANTIM.
Queen's alloy 9 i I I
Perrotine's alloy for rolls ......... 48 32-5 9 IO. 5
144. Bronzing is the process of staining or otherwise
coloring the surface of brass, in imitation of bronze — usually
imitating old bronze. The methods of bronzing and the
bronzing liquids are different for different purposes and as
practised in different localities and different trades. Brass is
very seriously subject to oxidation, and when polished soon
loses its brightness and its color. Polished surfaces are often
protected by the process of lacquering (to be presently de-
scribed), but the permanent preservation of the polish is rarely
possible and a coloring or bronzing is very commonly resorted
to. It was formerly customary to give scientific apparatus a
fine polish and to cover this surface with lacquer ; it is now
becoming more generally customary to bronze them or to
stain them either black or brown ; these are, in fact, but
modifications of one process.
To obtain the golden orange color characteristic of
brasses rich in copper, the piece may be polished and im-
mersed in a warm bath of the neutral solution of crystallized
acetate of copper for a moment, washing in clean water and
rubbing dry and bright. The chloride of antimony gives a
dark rich violet color, if the article is heated to nearly the
boiling point of water; sulphate of copper gives a watered
surface and copper nitrate a black.
Larkin used the hydrochlorate of copper with a little
238 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
free nitric acid, largely diluted, to produce a dark bronze;
a little acetic acid added to the solution of the same salt gave
a copper color, and the patina of antique bronze was imitated
by adding ammonia solution in large amount, or a quantity of
sal ammoniac.
" Bronze " paints are used for giving to the surface of iron,
or of any other material, the appearance of bronze ; they
have a great variety of composition ; some are composed of
filings, or powder, of brass mixed in some oil paint which
does not conceal the color of the bronze.
•
Graham's bronzing liquids, as published in 1861,* have a
great range of composition and of application as follows :
TABLE XXXII.
BRONZING LIQUIDS.
To be used for Brass by simple Immersion.
i
u
i
e
6
3
.a"
c
j,
3
e
I
J
•
6
3
t^
P
*§
.§
|
H
S
O
8
•3
§
1
•a
"o
"S
|
rate of iror
chloride oi
"o
i
rate of cop
o
0)
3
•a
i
riate of ars
t
3
1
irlash solut
a
"8
•rocyanide
phocyanid<
posulphite
ric acid.
ilic acid.
3
S
>,
a
No.
*
*
OH
£
fc
H
£
£
u
fo
in
S
15
pt.
dr.
dr.
pt.
oz.
gr.
OZ.
dr.
dr.
oz.
Pt.
dr.
dr.
dr.
oz.
J
5
j Brown, and every
\ shade to black.
16
j Brown, and every
j shade to red.
rrt
j
ii t»
I
Brownish red.
i
j
7
Dark brown.
§
6
Yellow to red.
Oranere
10
Olive-green.
5
2
Slate.
12
Blue.
13
I
Steel-gray.
14
2
Black.
In the preparation of No. 5, the liquid must be brought to boil and cooled. In using
No. 13, the heat of the liquid must not be under 180° F. No. 6 is slow in action, taking an
hour to produce good results. The action of the others is, for the most part, immediate.
* Brass Founders' Manual, Lond. 1870.
MANUFACTURE AND WORKING OF ALLOYS.
TABLE XXXII. — Continued.
To be used for Copper by simple Immersion.
239
1
c
1
A
&
o
e
^o
"c
£
8
Tj
C
1
a
1
<u
o
i
No.
I
Nitrate of in
Sulphate of
Sulphide of
I
Muriate of a
i
1
Sulphocyani
2
ffi
1
•o
pt.
dr.
oz.
dr.
dr.
dr.
oz.
dr.
oz.
dr.
1C
Brown, and every shade to black.
Tfi
5
Dark-brown drab.
17
i
i
2
T8
Bright red.
19
Red, and every shade to black.
20
••
i
••
•'•
Steel-gray, at 180° F.
For Zinc.
1
;
of potassium.
!
1
•
o
ON
^
rt
o
2
C/3
o
<u
O
£
>J
•d
u
C
«H
•g
0
"o
•g
c
1
•8
•o
u
?
1
1
3
^
^5
z
?
o.
'C
a
No.
1
2
1
1
3
1
X
-o
2
pt.
dr.
dr.
dr.
dr.
OZ.
OZ.
dr.
dr.
Black
" *
23
i
••
i
• •
i
••
Dark gray.
2S
*
*
26
2
••
••
X
Green-gray.
Red boil.
28
29
T
I
••
••
4
8
!!
..
4
's
"
X
Copper color. Plates so c A z.
Copper color, with agitation.
Purple boil.
145. Lacquering is the process of covering a polished
surface of brass or of other metal with a transparent or trans-
lucent coating, which, while protecting it from oxidation and
* Made to the consistency of cream.
24O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
discoloration, does not wholly conceal it. It is a process of
varnishing polished metal. It is applied also to the surfaces
of bronzed objects. Lacquer is a solution, usually, of some
vegetable gum or resin in alcohol or other effective colorless
solvent. In its application, great care is taken to keep the
piece to be lacquered warm and of uniform temperature, to
apply the solution quickly, smoothly and uniformly. The
usual solution is " shellac " in alcohol, and the best can, as a
rule, be made with the " stick " lac. It may be colored by
any permanent transparent alchoholic solution giving the
desired tint. The red coloring matters are, usually, dragon's
blood, red saunders or annotto ; the yellow are gamboge,
sandarac, saffron, turmeric or aloes. The following is
Graham's table of lacquers :
TABLE XXXIII.
LACQUERS.
No.
Shellac.
Mastic.
Canada Balsam.
SOLUTIONS.
REDS.
YELLOW.
Spirits of wine.
Pyro-acetic ether.
Spirits of turpentine.
Turpentine varnish.
V
1
<u
1
V
a
6
j»
Annotto.
Saunders.
Turmeric.
Gamboge.
Saffron.
1
!
Sandarac.
i
2
3
4
|
9
10
ii
12
«3
14
;i
;i
oz.
5
3
3
i
3
3
3
dr.
dr.
pt.
oz.
dr.
oz.
pt.
dr.
dr.
gr-
dr.
dr.
dr.
dr.
dr.
Strong simple.
Simple pale.
Fine pale.
Plate gold.
Pale yellow.
Ross's
Full yellow.
Gold.
Deep^gold.
Red.
Tin lacquer.
Green, for bronze.
i
2
3
••
i
i
i
8
••
32
16
4
8
8
..
30
2
••
16
••
6
6
2
14
5
Tfi
..
••
30
i
8
32
24
12
10
60
;;
ii
27
15
3°
3°
6
I
i
i
The union of red with yellow produces a fine orange color.
MANUFACTURE AND WORKING OF ALLOYS.
24I
The lacquers are kept in carefully stoppered bottles, and
it is better that they should be of opaque material, or of
glass impenetrable by actinic light capable of altering them ;
yellow glass is sometimes used. When in use, they are
poured into dishes of convenient size and form and are laid
on with a thin, wide flat brush.*
"Clouding" is performed by pouring on the surface a
mixture of fine charcoal dust in water, stirring it to obtain the
pattern, and then drying. The work is finally lacquered.
To Anneal Brass or Copper. — In working brass and
copper, it becomes hard, and if hammered may crack. To
prevent cracking, the piece must be heated to a dull red heat
and plunged in cold water ; this will soften it so it can be
worked. One must be careful not to heat brass too hot, or
it will fall to pieces. The piece should be annealed fre-
quently during the process of hammering.
TABLE OF SOLDERS. (Seep. 221.)
[Mechanical World.}
No.
Name.
Compositions.
Flux.
Fluxing1
Point.
i
2
3
4
5
6
1
9
10
ii
12
13
14
15
l6
T7
18
19
20
21
Plumbers' coarse solder
Plumbers1 sealed solder
Plumbers' fine solder
Tin, ; lead, 3...
Tin ; lead 2
R
R
R
RorZ
RorZ
B
B
B
B
R
B
B
B
B
B
RorZ
RorZ
RorZ
RorZ
RorZ
RorZ
800° Fahr.
441°
370°
334°
340°
320°
310°
292°
236°
202°
Tin, ; lead, 2
Tin, \ • lead, i
Tinners' solder
Tinners' fine solder
Hard solder for copper, brass, iron . .
Hard solder lor copper, brass, iron. .
Hard solder for copper, brass, iron
more fusible than 6 or 7
Tin, ; lead, i
Copper, 2 ; zinc, i
Good, tough brass, 5 ; zinc, i.
Copper, i ; zinc, i
Good tough plate brass
Silver, 19 ; copper, i ; brass, i
Silver, 2 • brass, i
Hard solder for copper, brass, iron . .
Silver solder for jewellers
Silver solder for plating. . . .
Silver solder for silver, brass, iron . .
Silver solder for steel joints
Silver solder more fusible
Gold solder
Silver, i ; brass, i
Silver, IQ ; copper, i ; brass, i
Silver, 5 ; brass, 5 ; zinc, 5 ...
Gold, 12 ; silver, 2 ; copper, 4
Lead, 4 ; tin, 4 ; bismuth, i..
Lead, 3 ; tin, 3 ; bismuth, i . .
Lead, 2 ; tin, 2 ; bismuth, i..
Lead, 2 ; tin, i ; bismuth, 2. .
Lead, 3 ; tin, 5 ; bismuth, 3..
Lead, 4; tin, 3; bismuth, 2..
Bismuth solder
Bismuth solder
Bismuth solder
Bismuth solder
Bismuth solder
Pewterers' solder
Abbreviations : R, resin ; B, borax ; Z, chloride of zinc.
Vide Part I, § 196, p. 335, for lacquers and browning liquids for fire-arms.
etc.
CHAPTER VIII.
STRENGTH, ELASTICITY AND DUCTILITY OF THE NON-
FERROUS METALS.
146. The Strength of Non-ferrous Metals and other
mechanical properties have not attracted as much attention
as the engineer would desire. Investigations have been
few in number, generally very incomplete, and as a rule
unfruitful, in comparison with those relating to iron and
steel.
In recording and discussing experimental work on the
non-ferrous metals and their alloys, the system and nomen-
clature adopted will be that employed in the study of the
strength of iron and steel. The following summary will here
suffice.* Following it, will be given a statement of the re-
sults of experiments made upon the non-ferrous metals, suc-
ceeded by chapters describing investigations of the strength
and elasticity of their alloys, and the conditions modifying
strength.
147. The Resistance of Metal to rupture may be brought
into play by either of several methods of stress, which have
been thus divided by the Author:
Longitudinal \ Tensile : resisting pulling force.
( Compression : resisting crushing force.
( Shearing : resisting cutting across.
Transverse J Bending : resisting cross breaking.
( Torsional : resisting twisting stress.
* Abridged and adapted from Part II., Chapter IX. For the theory of the
elasticity and strength of materials, consult "Wood's Resistance of Materials,**
published by J. Wiley & Sons, and Burr's work OP the same subject issued bj
the same publishers.
STRENGTH OF NON-FERROUS METALS. 243
When a load is applied to any part of a structure or of a
machine it causes a change of form, which may be very
slight, but which always takes place, however small the load.
This change of form is resisted by the internal molecular
forces of the piece, i.e., by its cohesion. The change of form
thus produced is called strain, and the acting force is a stress.
The Ultimate Strength of a piece is the maximum resist-
ance under load — the greatest stress that can exist before
rupture. The Proof Strength is the load applied to deter-
mine the value of the material tested when it is not intended
that observable deformation shall take place. It is usually
equal, or nearly so, to the maximum elastic resistance of the
piece. It is sometimes said that this load, long COD >dnued,
will produce fracture ; but, as will be seen hereafter^ 0;his is
not necessarily, even if ever, true.
The Working Load is that which the piece is proportioned
to bear. It is the load carried in ordinary working, and is
usually less than the proof load, and is always some fraction,
determined by circumstances, of the ultimate strength.
A Dead Load is applied without shock, and, once applied,
remains unchanged, as, e.g., the weight of a bridge; it pro-
duces a uniform stress. A Live Load is applied suddej^y,
and may produce a variable stress, as, e.g., by the passage of
a railroad train over a bridge.
The Distortion of the strained piece is related to the load
in a manner best indicated by strain diagrams. Its value as
a factor of the measure of shock-resisting power, or of re-
silience, is exhibited in a later article. It also has importance
as indicating the ductile qualities of the metal.
The Reduction of Area of Section under a breaking load is
similarly indicative of the ductility of the material, and is to
be noted in conjunction with the distortion.
E.g. A considerable reduction of section with a" smaller
proportional extension would indicate a lack of homogeneous-
ness, and that the piece had broken at the soft part of the
bar. The greater the extension in proportion to the reduc-
tion of area in tension, the more uniform the character of the
metal.
244 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
148. Factors of Safety. — The ultimate strength, or maxi.
mum capacity for resisting stress, has a ratio to the maximum
stress due to the working load, which, although less in metal
than in wooden or stone structures, is, nevertheless, made of
considerable magnitude in many cases. It is much greater
under moving than under steady " dead " loads, and varies
with the character of the material used. For machinery it is
usually 6 or 8 ; for structures erected by the civil engineer,
from 5 to 6. The following may be taken as minimum values
of this " factor of safety for the non-ferrous metals : "
MATERIAL.
LOAD.
SHOCK.
Dead.
Live.
Copper and other soft metals
and alloys
5
4
8
7
10 -f
10 to 15
Ratio of Ultimate
Strength to
Working Load.
The brittle metals and alloys .
The Proof Strength usually exceeds the working load from
50 per cent., with tough metals, to 200 or 300 per cent, where
brittle materials are used. It should usually be below the
elastic limit of the material.
As this limit, with brittle materials, is often nearly equal
to their ultimate strength, a set of factors of safety, based on
the elastic limit, would differ much from those above given
for ductile metals, but would be about the same for all brittle
materials, thus :
MATERIAL.
LOAD.
SHOCK.
Dead.
Live.
Soft metals
2
3
4
6
6
8 to 12
Ratio of Elastic
Resistance to
Working Load.
Brittle metals and alloys. . . .
The figure given for shock is to be taken as approximate,
but used only when it is not practicable to calculate the
energy of impact and the resilience of the piece meeting it,
and thus to make an exact calculation of proportions.
STRENG TH OF NON-FERRO US ME TALS. 24$
The factors of safety adopted for non-ferrous metals are
higher than those usually adopted for construction in iron or
steel in consequence of the fact that the elastic limit and the
elastic resilience, or shock-resisting power, of the latter seem
to increase with strain, up to a limit; while the former
gradually yield under comparatively low stresses, as will be
seen hereafter. In common practice, the factor of safety
covers not only risks of injury by accidental excessive
stresses, but deterioration with time, uncertainty as to the
character of uninspected material, and sometimes equally
great uncertainty as to the absolute correctness of the for-
mulas and the constants used in the calculations. As inspec-
tion becomes more efficient and trustworthy; as our knowl-
edge of the effect of prolonged and of intermittent stress
becomes more certain and complete ; as our formulas are
improved and rationalized, and as their empirically deter-
mined constants are more exactly obtained, the factor of
safety is gradually reduced, and will finally become a mini-
mum when the engineer acquires the ability to assume with
confidence the conditions to be estimated upon, and to say
with precision how his materials will continuously carry their
loads.
A characteristic distinction between the ductile non-ferrous
metals and ductile iron or steel, is that the former have
usually, as purchased, no true elastic limit, but yield to small
stresses without recovery of form and their permanent set
equals their maximum distortion. Where brittle, they are
often very elastic, however, and recover fully. In such cases,
the elastic limit coincides with their ultimate resistance to
fracture, as is the case with glass, hard cast iron, and often
with hardened steel.
In the table above it is assumed that an elastic limit
occurs at the point at which the elongation becomes o.ooio of
the total length of the piece stretched.
In some cases it is advisable to design some minor part,
or element, of a train with a lower factor of safety, to insure
that when a breakdown does occur it shall be certain to take
place where it will* do least harm.
246 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
149. The Measure of Resistance to strain is determined,
in form, by the character of the stress. By stress is here
understood the force exerted, and by strain the change of
form produced by it.
Tenacity is resistance to a pulling stress, and is measured
by the resistance of a section, one unit in area, as in pounds
or tons on the square inch, or in kilogrammes per square cen-
timetre or square millimetre. Then, if T represents the
tenacity and K is the section resisting rupture, the total load
that can be sustained is, as a maximum,
(i)
Compression is similarly measured, and if C be the maxi-
mum resistance to crushing per unit of area, and K the sec-
tion, the maximum load will be
(2)
Shearing is resisted by forces expressed in the same way,
and the maximum shearing stress borne by any section is
(3)
Bending Stresses are measured by moments expressed by
the product of the bending effort into its lever-arm about the
section strained, and if P is the resultant load, / the lever-arm
and J/the moment of resistance of the section considered,
Pl=M ........ (4)
Torsional Stresses are also measured by the moment of
the stress exerted, and the quantity of attacking and resist-
ing moments is expressed as in the last case.
Elasticity is measured by the longitudinal force, which,
acting on a unit of area of the resisting section, if elasticity
were to remain unimpaired, would extend the piece to double
its original length. Within the limit at which elasticity is
unimpaired, the variation of length is proportional to the
STRENGTH OF NON-FERROUS METALS. 247
force acting, and if E is the "Modulus of Elasticity" or
" Young's Modulus," / the length, and e the extension, P
being the total load, and K the section :
Pi
The Coefficients entering into these several expressions for
resistance of materials are often called Moduli, and the forms
of the expressions in which they appear are deduced by the
Theory of the Resistance of Materials, and the processes are
given in detail in works on that subject.
These moduli, or coefficients, as will be seen, have values
which are rarely the same in any two cases ; but vary not
only with the kind of material, but with every variation, in
the same substance, of structure, size, form, age, chemical
composition or physical character, with every change of tem-
perature, and even with the rate of distortion and method of
action of the distorting force. Values for each familiar ma-
terial, for a wide range of conditions, will be given in the
following pages.
150. Method of Resistance to Stress. — When a piece of
metal is subjected to stress exceeding its power of resistance
for the moment, and gradually increasing up to the limit at
which rupture takes place, it yields and becomes distorted at
a rate which has a definitely variable relation to the magni-
tude of the distorting force; this relation, although very
similar for all metals of any one kind, differs greatly for differ-
ent metals, and is subject to observable alteration by every
measurable difference in chemical composition or in physical
structure.
Thus, in Fig. 2, let this operation be represented by the
several curves, a, b, c, d, etc., the elevation of any point on
the curve above the axis of abscissas, OX, being made pro-
portional to the resistance to distortion of the piece, and to
the equivalent distorting stress, at the instant when its dis-
248 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
tance from the left side of the diagram, or the axis of ordi-
nates, OY, measures the coincident distortion. As drawn, the
strain-diagram, a a , is such as would be made by a soft metal
like tin or lead ; b b' represents a harder, and c c' a still harder
and stronger metal, as zinc and rolled copper. If the smallest
divisions measure the per cent, of extension horizontally, and
10,000 pounds per square inch (703 kilogrammes per square
centimetre) vertically, d d' ', would fairly represent a hard iron,
or a puddled or a " mild " steel ; while//' and gg' would be
strain diagrams of hard, and of very hard tool steels, respect-
ively.
The points marked e, e', e", etc., are the so-called *' elastic
FIG. 2. — STRAIN-DIAGRAMS.
limits'" at which the rate of distortion more or less suddenly
changes, and the elevation becomes more nearly equal to the
permanent change of form, and at these points the resistance
to further change increases much more slowly than before.
This change of rate of increase in resistance continues until
a maximum is reached, and, ^passing that point, the piece
either breaks, as at/' and g' , or yields more and more easily
until distortion ceases, or until fracture takes place, and it
becomes zero at the base line, as at X.
Such curves have been called by the Author " Strain-
diagrams."
151. Equations of Curves of Resistance or Strain-dia-
grams.— These curves are, at the start, often nearly para-
STRENGTH OF NON-FERROUS METALS. 249
bolic, and the strain-diagrams of cast iron, //, i, k, having their
origin at 0, are usually capable of being quite accurately ex-
pressed by an equation of the parabolic form, as
in which the Author found the constants for copper in tension
to be
A = 10,000,000 ; B = 100,000,000,
and where -j is the ratio of elongation to the length of the
piece, and /*, the load, is measured for tension, in pounds on
the square inch of resisting section.
For bronze of fair quality, the Author has, in some ex-
periments, obtained :
A = 12,000,000; B = 50,000,000.
For brass, he obtained nearly :
A = 12,000,000; B — 50,000,000.
The coefficient A, above, is the modulus of elasticity.
Reducing the above quantities to metric measure — kilo-
grammes on the square centimetre — we have :
A. B.
For copper ........................ 703,000 7,030,000
For bronze ........................ 843,600 3,515,000
For brass .......................... 843,600 3,515.000
152. The Series of Elastic Limits. — If, at any moment,
the stress producing distortion is relaxed, the piece recoils
and continues this reversed distortion until, all load being
taken off, the recoil ceases and the piece takes its "per-
manent set." This change is shown in the figure at/"/",
the gradual reduction of load and coincident partial restora-
tion of shape being represented by a succession of points
forming the line f" f", each of which points has a position
which is determined by the elastic resistance of the piece as
250 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
now altered by the strain to which it has been subjected.
The distance Of" measures the permanent set, and the dis-
tance/"/"' measures the recoil.
The piece now has qualities which are quite different from
those which distinguished it originally, and it may be re-
garded as a new specimen and as quite a different metal. Its
strain-diagram now has its origin at/", and the piece being
once more strained, its behavior will be represented by the
curve/"/" evlf, a curve which often bears little resemblance
to the original diagram O,f,f. The new diagram shows an
elastic limit at ev, and very much higher than the original
limit *IV. Had this experiment been performed at any other
point along the line//', the same result would have followed.
It thus becomes evident that the strain-diagram is a curve of
elastic limits, each point being at once representative of the
resistance of the piece in a certain condition of distortion,
and of its elastic limit as then strained.
The ductile, non-ferrous metals, and iron and steel, and
the truly elastic substances, have this in common — that the
effect of strain is to produce a change in the mode of resist-
ance to stress, which results, in the latter, in the production
of a new and elevated elastic limit, and in the former in the
introduction of such a limit where none was observable be-
fore.
It becomes necessary to distinguish these elastic limits in
describing the behavior of strained metals? and, as will be
seen subsequently, the elastic limits here described are, under
some conditions, altered by strain, and we thus have another
form of elastic limit to be defined by a special term.
In this work the original elastic limit of the piece in its
ordinary state, as at e, e' , e", etc., will be called either the
Original, or the Primitive, Elastic Limit, and the elastic limit
corresponding to any point in the strain-diagram produced
by gradual, unintermitted strain, will be called the Normal
Elastic Limit for the given strain. It is seen that the dia-
gram representing this kind of strain is a Curve of Normal
Elastic Limits.
The elastic limit is often said to be that point at which
STRENGTH OF NON-FERROUS METALS. 2$ I
a permanent set takes place. As will be seen on studying
actual strain-diagrams to be hereafter given, and which
exhibit accurately the behavior of the metal under stress,
there is no such point. The elastic limit referred to ordina-
rily, when the term is used, is that point within which recoil,
on removal of load, is approximately equal to the elongation
attained and beyond which set becomes nearly equal to total
elongation.
It is seen that, within the elastic limit, sets and elongations
are similarly proportional to the loads, that the same is true
on any elastic line, and that loads and elongations are nearly
proportional everywhere beyond the elastic limit, within a
moderate range, although the total distortion then bears a
far higher ratio to the load, while the sets become nearly
equal to the total elongations.
153. Effect of Shock or Impact ; Resilience.— The be-
havior of metals, under moving, or " live," load and under
shock, is not the same as when gradually and steadily strained
by a slowly applied or static stress. In the latter case, the
metal undergoes the changes illustrated by the strain
diagrams, until a point is reached at which equilibrium occurs
between the applied load and resisting forces, and the body
rests indefinitely, as under a permanent load, without other
change occurring than such settlement of parts as will bring
the whole structural resistance into play.
When a freely moving body strikes upon the resisting
piece, on the other hand, it only comes to rest when all its
kinetic energy is taken up by the resisting piece ; there is
then an equality of vis viva expended and work done, which
is expressed thus :
WV*
in which expression W is the weight of the striking body, V
its velocity, p the resisting force at any instant, pm the mean
resistance up to the point at which equilibrium occurs, and s
is the distance through which resistance is met.
252 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
As has been seen, the resistance may usually be taken as
varying approximately with the ordinates of a parabola, the
abscissas representing extensions. The mean resistance is,
therefore, nearly two-thirds the maximum, and
wv*
~' ' = ae*9 nearly . . (8)
where e is the extension, and t the maximum resistance at
that extension, and a a constant. Brittle materials, like hard
bronzes and brasses, have a straight line for their strain-
diagrams, and the coefficient becomes J^ instead of %, and
WV2
(9)
154. Resilience, or Spring, is the work of resistance up
to the elastic limit. This will be called Elastic Resilience.
The modulus of elasticity being known, the Modulus of
Elastic Resilience is obtained by dividing half the square of
the maximum elastic resistance by the modulus of elasticity,
E, as above, and the work done to the "primitive elastic
limit " is obtained by multiplying this modulus of resilience
by the volume of the bar.*
The total area of the diagram, measuring the total work
done up to rupture, will be called a measure of Total or Ulti*
mate Resilience. Mallett's Coefficient of Total Resilience is
the half product of maximum resistance into total extension.
It is correct for brittle substances and all cases in which the
primitive elastic limit is found at the point of rupture. With
tough materials, the coefficient is more nearly two-thirds —
and may be even greater where the metal is very ductile, as,
e.g., pure copper, tin, or lead. Unity of length and of section
* Rankine and some other writers take this modulus as — , instead of $ — ,
£L, £•
STRENGTH OF NON-FERROUS METALS. 2$$
being taken, this coefficient is here called the Modulus of
Resilience.
When the energy of a striking body exceeds the total re-
silience of the material, the piece will be broken. When the
energy expended is less, the piece will be strained until the
work done in resistance equals that energy, when the striking
body will be brought to rest.
As the resistance is partly due to the inertia of the
particles of the piece attacked, the strain-diagram area is
always less than the real work of resistance, and, at high ve-
locities, may be very considerably less, the difference being
expended in the local deformation of that part of the piece
at which the blow is received. In predicting the effect of a
shock it is, therefore, necessary to know not only the energy
stored in the moving mass and the method of variation of the
resistance, but also the striking velocity. To meet a shock
successfully it is seen that resilience must be secured sufficient
to take up the shock without rupture, or, if possible, without
serious deformation. It is, in most cases, necessary to make
the elastic resilience greater than the maximum energy of any
attacking body.
Moving Loads produce an effect intermediate between that
due to static stress and that due to the shock of a freely mov-
ing body acting by its inertia wholly ; these cases are, there-
fore, met in design by the use of a high factor of safety, as
above.
As is seen by a glance at the strain-diagram, ff (Fig. 2),
the piece once strained has a higher elastic resilience than at
first, and it is therefore safer against permanent distortion by
moderate shocks, while the approach of permanent extension
to a limit renders it less secure against shocks of such great
intensity as to endanger the piece.
When the shock is completely taken up, the piece recoils,
as at e*f"f", until it settles at such a point on that line — as-
suming the shock to have extended the piece to the point e*
—that the static resistance just equilibrates the static load.
This point is usually reached after a series of vibrations on
either side of it has occurred. With perfect elasticity, this
254 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
point is at one-half the maximum resistance, or elongation,
attained. Thus we have
but/ varies as x within the elastic limit, which limit has now
risen to some new point along the line of normal elastic
limits, as e*. Taking the origin at the foot of/'/", since
the variations of length along the line Ox are equal to the
elongations and to the distances traversed as the load falls,
and as stresses are now proportional to elongations,
p=ax\ Wh=Ws- <andW=P . . . (11)
when the resisting force is/, the elongations x, while h and s
are maximum fall and elongation, and P is the maximum
resistance to the load at rest. Then
f* f* a zW
\pdx=a\xdx = -<?=Ws.\s=- -. . (12)
J 0 J 0 2 a
For a static load, if s' is the elongation,
W
W=P=as' .'. y = — .
a
Hence, |=# ...... . . (13)
and the extension and the corresponding stress due to the
sudden application of a load are double those produced by a
static load.
Where the applied load is a pressure and not a weight,
i.e., where considerable energy in a moving body is not to be
absorbed, as in the action of steam in a steam engine, the
only increase of strain produced by a suddenly applied load
is that produced by the inertia of such of those parts of the
mass attacked as may have taken up motion and energy.
STRENGTH OF NON-FERROUS METALS. 2$$
155. Proportioning to Resist Shock. — The problem of
proportioning parts to resist shock is thus seen to involve a
determination of the energy, or " living force," of the load at
impact, and an adjustment of proportion of section and shape
of piece attacked such that its work of elastic or of ultimate
resilience, whichever is taken as the limit, shall exceed that
energy in a proportion measured by the factor of safety
adopted. For ordinary live loads and moderate impact, re-
quiring no specially detailed consideration, the factors of
safety already given (Art. 148), as based upon ultimate
strength simply, are considered sufficient ; in all cases of
doubt, or when heavy shock is anticipated, calculations of
energy and resilience are necessary, and these demand a com-
plete knowledge of the character, chemical, physical, and
structural, of every piece involved, of its resilience and
method of yielding under stress, and of every condition in-
fluencing the application of the attacking force — in other
words, a complete knowledge of the material used, of the
members constructed of it, and of the circumstances likely to
bring about its failure.
The form of such parts should usually be determined on
the assumption that deformation may some time occur, and
such expedients as that of Hodgkinson in enlarging the sec-
tion on the weaker side, as well as the adoption of a larger
factor of safety based on ultimate strength, are advisable.
156. The Methods of Testing and the construction of
the machines used are fully described in Part II. of this work.
The form of test-piece advisable, and standard formulas, and
many facts relating to this part of the subject may be there
studied, or in works on the strength of materials.
157. Compression. — Resistance to Compression is measured
by the same process as in testing by tension. This form of
resistance is, however, governed in many cases by different
laws, and is often modified by the size and shape of the piece
tested to even greater extent than is resistance to tensile
stress. The method of rupture is not only different for differ-
ent materials, but it is different with pieces of the same metal
for every difference in size, shape, or proportion. Thus, a
2$6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
piece of copper or lead is soft and tough, and, in the form of
a short cylindrical column, will gradually yield by crushing
until it assumes the form of a cheese, or a button; the same
metal in longer cylinders will yield similarly, until, reaching a
certain limit, as in long columns, it will yield by bending
laterally, and under a comparatively small load. A piece ot
speculum metal, or of other brittle metal or alloy, will break
by crushing into fragments, and will break up the more com-
pletely as it is harder and more brittle. Extremely hard
metals and alloys exhibit no sign of yielding until their limit
of resistance is reached, when they suddenly fly to pieces with
great violence.
In all cases, resistance increases up to a limit beyond
which the piece usually gives way suddenly, if the metal be
hard or brittle ; while ductile and malleable metals often offer
constantly increasing resistance, the limit being reached only
when the pressure becomes so great as to cause the metal to
flow steadily, as is illustrated in the manufacture of lead
pipe.
In consequence of these variations due to form and size,
it is even more necessary than when testing by tension to
have a standard form of test-piece, as proposed in Part II.,
and to report all observations as made upon such standard.
158. The Structure of the Piece and its Chemical Com-
position determine the compressive resistance of metals and
alloys. With pure, well-worked metal, the resistance follows
pretty closely a law peculiar to and characteristic of each
metal. Within the elastic limit, the behavior of the piece
may be taken as the same, whether under tension or compres-
sion ; beyond that limit, the compressive strength usually ex-
ceeds the tensile in a proportion which varies greatly. Copper
and other non-ferrous metals are rarely used in the form of
columns. Should it be necessary to so use them, the formu-
las given in Part II. and in special works on strength of ma-
terials may be used, substituting the proper value, C, of the
modulus for compression.
159. The Transverse Strength, or the resistance of any
piece to bending, is determined by the longitudinal strength
STRENGTH OF NON-FERROUS METALS. 2$;
of the metal, both in tension and compression, by the form
of the piece, and by its absolute dimensions. When this
method of stress affects a bar of metal, there is called into
action at every section a set of forces resisting flexure, each
acting about a *' neutral line" at which the forces change
sign. If a bar is placed in the testing machine, and if, while
supporting it at each end, the machine is made to apply a
depressing force at the middle of the piece, the upper part of
the bar is compressed, and the lower extended ; while be-
tween these portions of strained metal is a plane of unstrained
material, whose trace on the vertical plane is the neutral line.
The moments of the forces by which the bar resists compres-
sion above and extension below this plane, together produce
the measured resistance to flexure. The position of the neu-
tral plane is determined by the relation existing between the
magnitudes of the two forms of resistance ; it may be con-
sidered as always at the middle of the section, within the
elastic limit, while beyond that limit it approaches that side
at which resistance is greatest at the moment. The total
resistance to flexure, then, is measured by the sum of these
two moments of resistance, which are themselves measured
each by the product of the mean resistance of the strained
parts of the most severely loaded cross section affected by it
into its own lever arm.
By the ordinary theory, and its resulting equations, the
resistances of particles to compression and to extension are
taken proportional to their distance from the neutral surface ;
this is correct up to that limit of flexure at which the exte-
rior sets of particles on the one side or on the other are
forced beyond the elastic limit. With absolutely non-ductile
materials, or materials destitute of viscosity, fracture occurs
at this point; but, with nearly all of the metals and alloys in
common use, rupture does not then take place. The exterior
portions of the mass are compressed on the one side, offering
more and more resistance nearly, if not quite, up to the point
of actual breaking, which breaking may only occur long after
passing the elastic limit ; on the other side, similar sets of
particles are drawn apart, passing the elastic limit for tension,
17
258 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and then resisting the stress with a more nearly constant
force, " flow " occurring until the limit of that flow is reached,
and rupture takes place.
No expressions have yet been derived by analysis, and
constants determined by experiment, which enable the engi-
neer to express by an equation the actual method of varia-
tion of internal resistances with variation of load and of de-
flection, for all materials ; but sufficient accuracy is usually
obtained for practical purposes by treating the case in the
simplest manner.
160. Methods of Distribution of Resistances, in cases of
flexure, are exhibited in the accompanying figures.
FIG. 3. — FLEXED ELASTIC BEAM.
In MN, the material being perfectly elastic up to the
limit of flexure, the stress at any point is proportional to the
area of the element strained, to the maximum elastic resist-
ance Oi* the material, and to the distance x of the element
from the neutral plane MON. The resistance to flexure
within the range of perfect elasticity is, therefore, in this
case, as when the beam is ruptured, at that limit proportional
to the breadth of the piece and to the square of the depth,
where the section is rectangular.
Where a metallic beam is strained beyond the elastic
limit at any part of its sec-
tion, the stress outside that
part is more nearly con-
stant, and may become
equal to the maximum re-
sistance of the material, or
nearly so. Thus, in Fig. 4, the law of resistance changes
at a and is no longer proportional to the distance of the
FIG. 4.
STRENGTH OF NON-FERROUS METALS.
strained particles from the neutral plane, but has the maxi-
mum possible value. This change may occur abruptly, as
shown, or gradually, making the shaded parts exhibiting the
magnitude of the stress
a pair of parabolas placed
vertex to vertex. Finally,
with all perfectly ductile M'
materials, all parts of the *""
section become equally
strained, nearly as in Fig. 5.
161. Theory of Rupture.* — In the usual case, in which
the resistance to distortion varies from a maximum, R, at the
outer surface to zero on the neutral plane, as in brittle ma-
terials, we have for the elementary area dy dx, for the resist-
r> r>
ance—j/ per unit of area, and-y y dy dx on the area dy dx\
while the moment of resistance, M, on that part of the whole
section which lies on one side the neutral plane is obtained
by integration from that line to the most strained fibre on
that side, at a distance </„ R being the " Modulus of Rupture " :
fb Fdi
P fb Fdi
\fdydx =
a i J o Jo
i.e., the quotient of the modulus of rupture by the distance
of the most strained fibre from the neutral line, multiplied by
the moment of inertia of the section considered.
When the resistance, after passing the elastic limit, be-
comes throughout equal to the maximum R, we have per
unit of area, a resistance R dy dx, and for the moment
fb rdi
ydy
o Jo
dx = M'.
For rectangular beams, when the neutral line may be
taken at the middle of the section, as with non-ductile ma-
terials generally for the first, and for copper, tin, lead and
* See Wood's " Resistance of Materials " for tbe Theory of Resistance.
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
other substances having nearly equal values of T and Cy for
the second case, we get, for the two cases respectively :
(a) M=^Rbd2', (b) M* =
b being the breadth, and d— 2</x the total depth of section.
Thus, assuming the same value for ultimate resistance of
cohesion, the ductile substance offers one-half greater resist-
ance than the non-ductile, and one-half greater resistance
just beyond than just within the elastic limit. Hence, also,
it can only be expected that the value of R will coincide with
the resistance to direct tension or direct compression in rare
cases. It is evident that the actual value of R may be com-
pared with the values of T and C, to determine to what
extent the case approaches that giving the second of these
equations.
The first of these cases is that which it has been custom-
ary to assume as applicable in all cases. Its solution evi-
dently gives results differing from the truth on the right side.
Examining the equation, it is seen that the moment of re-
sistance, M, is measured by the product of the " modulus " of
rupture, R, into the quantity \\y*dydx divided by the depth
dj_ to the neutral line, or as, shown by M. Navier, to the axis
through the centre of gravity. The quantity \\fdy dx,
which is always a factor in this expression, is the " moment
of inertia."
The data to be here given are experimentally obtained
figures, derived from tests of pieces of rectangular section ;
other forms will be considered later.
162. Formulas for Transverse Loading are deduced in
all works on resistance of materials. For cases of rupture,
when the beam is supported at the ends and loaded in the
middle, for rectangular bars,
M= -PI = \Rbd* ; and R =
4 6
STRENGTH OF NON-FERROUS METALS. 26l
for non-ductile materials, and it may be assumed, in all cases
in the engineer's practice, that the material tested is in prac-
tice either sufficiently elastic and rigid to justify the use of
this formula, or is to be loaded only within its elastic limit.
Then the formulas for other cases become :
(i.) Beam fixed at one end, load at the other:
Pl=l-,Rbd*-y P=*R^L.
6 6 /
(2.) Same, with load distributed uniformly :
(3.) Beam supported at ends, loaded at middle:
LPl=M, P=2-R^-
(4.) Same, uniformly loaded :
l-Wl=M; W=*R*^-.
(5.) Beam firmly fixed at ends, loaded at middle:
l-Pl=M;
Same determined by Barlow's experiments:
'/y=J/; P=R*f.
6 /
(6.) Same uniformly loaded :
-LW7=J/; W=2
12
2*52 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
(7.) Fixed at one end, supported at the other, load at the
middle:
All of these equations are, of course, " homogeneous."
Replacing bd2 by o.59</3, transforms these quotations so
as to apply very exactly to circular sections.
163. The Modulus of Rupture, R, being obtained by
experiment and inserted in these formulas, the maximum
load that a beam will support, when of similar shape and of
that material, becomes calculable.
The value of the modulus of rupture is readily deter-
mined by experiment from the formula :
when the weight of the beam, Wy is taken into account.
When the dimensions all become unity, we have, neglecting
that is to say, the modulus of rupture is one and a half times
the load which would break a bar unity in length, breadth
and depth, supported at the ends and loaded in the middle.
For British measures, it is 1 8 times the weight that would
break a bar so loaded if one foot long, and one inch square
in section.
Very ductile bars bend without breaking. The correct
modulus of rupture in these cases, therefore, cannot be de-
termined, and it is necessary to assume a given amount of
bending as equivalent to breaking the bar or rendering it
useless, and the modulus of rupture is calculated from the
load causing this maximum deflection, to afford a means of
comparing the transverse strengths of all bars which were
tested.
STRENGTH OF NON-FERROUS METALS.
263
164. The Theory of Elastic Resistance, as generally ac-
cepted, is as follows :
In figure 6, which represents a longitudinal section through
a loaded beam, let EFbe. the neutral line extending through-
out its length. Let AB and
CD be consecutive transverse
sections separated by the dis-
tance dx ; C' D' is the position
of C when swung out of its
original place by the action of
the load W, and its intersection
with the plane AB is found at
R. Then, ab being the original FlG 6
length of any fibre at a dis-
tance Ob — jt from the neutral axis, be = A will be its elonga-
tion, and if the radius of curvature, OR, is called p, we have
A C C
E-...
a
6
— b
£ _
I
^D'D
•R
and the stress on any fibre of the area, a-=dy dz, since
A, E
: E : : A : dx, will be
a
and the moment about the intersection with the neutral line
is
accordingly as the fibre is above or below that line.
The total moment will be
77 f£ tdi 77 tb e
=£J fdydx + -\
P Jo Jo P Jo J
b ed2
o Jo
For cases in which the section is symmetrical about the
neutral line
El
264 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
in which integrals b is the breadth of section, d^ and d2 are
the depth of the half sections above and below EF, and d is
the total depth. Also,
El
M = — .
P
The value of p, the radius of curvature, is shown in works
on the differential calculus to be
..(•*£)'.
p=±
dx*
which value reduces the equation for M = PI, as in Fig. 6, to
pt — M- — pj
1
dv*
when -gj may, as is probably usually the case, be neg-
lected.
Inserting the value of M in terms of x, we have, for ex-
ample, with the " cantilever," or beam fixed at one end,
loaded at the other, origin at the fixed end :
which, being integrated once, gives
where x = O, -2- = O, and C= O.
Again integrating, and
STRENGTH OF NON-FERROUS METALS. 26$
in which, where x — O, y — O and C = O, and the value for
deflection at x — I, for this case is
PI*
as already given.
For uniform loading,
and
All usual cases are developed in treatises on the theory of
the resistance of materials.
The elastic resistance to flexure is of greater importance
in very many cases than the ultimate transverse strength, as
pieces are in machinery almost invariably, and in other struct-
ures usually, rendered useless when the change of form ex-
ceeds a limit which is generally intended to be well within
the elastic range.
In some of the tables, the figures in the column headed
" Modulus of Elasticity," are those which are considered the
most probable moduli within the elastic limit, or which most
nearly represent the relation between the stresses and the
distortions within that limit.
In a few instances the apparent modulus at the beginning
of the test is much smaller than it soon afterward becomes;
and this indicates either a possible error or the existence of
internal stress at this part of the test.
In general, we have, within the elastic limit,
n_. P-.
~$£r i3
for the case of a beam fixed at one end and loaded at the
other.
266 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
When uniformly loaded,
For beams supported at the ends, these equations fof
single and distributed loads are
n ' L?L- P
~ '
For beams fixed at the ends, we have
20oD£f
D
D = - - -j^: , nearly ; P =
200 El
U7
D—— -^- » nearly; W—-— r- —
400 El /3
For rectangular beams,
and we may write the simplified formula for a beam sup«
ported at the ends and loaded in the middle,
'
For a beam fixed at one end and loaded at the other,
_ i6aPl*
and, when uniformly loaded, the t o cases give
~ 8 bd
and
STRENGTH OF NON-FERROUS METALS. 26?
Where the length is measured in inches,
I 1728
a = .— =» and when in feet, a — ' „ *
4h 4£
165. The Torsional Strength and elasticity of iron and
steel have been less thoroughly investigated than either of
the other forms of resistance.
The moment of the applied force, as measured by the
product of the magnitude of that force into the length of its
lever-arm, at each instant equilibrates the resistance, and the
formula for elastic resistance becomes:
,-,, ,,, 2ns fri _ y
Fl = M = - 7* dr.
For solid cylinders,
Fl = M = i.tfoSsr? = 0.2sd*.
For hollow cylinders,
Fl=M= 1.5708*
where F is the applied force, / its lever-arm, M its moment, s
the resistance of the material on the unit of area, or the
maximum stress, r0 and r^ are the radii of the shaft, internal
and external, and d0 and dv are the diameters.
The angle of torsion is proportional to the length of the
part twisted and to the torsional moment. The formula
giving its value is
_ 2Mx _ -$2M x _ Fix
— ~~^ ~ — - * * "=i — I O» 2
/^ — — 7T /^ — »v*^ X- 7 ,. t
Orr,4 7f4J C Cd*
x being the length of the part twisted ;
Ft=M= aC^~= 0.098(7^ ,
?)2X X
in which formulas C is the coefficient of elasticity of torsion.
268 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
166. The Strength of a Metal Shaft depends not only
on the magnitude of the ultimate resistance of the mate-
rial, but upon the method of its action. With brittle mate-
rials, fracture must occur when the limit of resistance of the
outer layers is reached ; with ductile metals, capable of flow,
fracture may not take place until all, or nearly all, parts of
the cross section have been highly strained, the outer portions
yielding by flow until the inner parts have been strained to
their maximum.
For the first case, we have for the area of each elementary
9 ¥
ring, 2itr dr> for the stress upon it s = -J— , and for its lever-
ri
arm, r.
Then
for hollow shafts, and when r0 = O, d0 = O, as for solid shafts,
Fl=M= 1.5708 slr,3 = 0.196 Sjd*.
To obtain the diameter, we have :
For solid shafts,
For hollow shafts,
.(•-£)
In these formulas, the ultimate resistance may be taken
as already given for tension, and the factor of safety should
usually be large.
When the material is capable of flow to such an extent
that the whole section resists with maximum effect, we have
STRENGTH OF NON-FERROUS METALS. 269
the elementary area as before — 27trdr, its lever- arm /•, and
the value of s becomes constant and equal to sv
Then
Fl = 27TS, \\*dr = - ns1 (r? - r03) = 0.26^ (4 - d0)9
J ro 3
and when r0 = o,
^3 = 2.2str*.
In such cases, therefore, the strength of the shaft is in-
creased one-third by the ductility of the metal.* It is uncer-
tain to what extent this action occurs, and it is still more
uncertain to what extent the action here occurring is a true
shearing action. The last set of formulas, above deduced,
are rarely used by the engineer.
When the section is square, the resistance is increased
about 40 per cent, above that of a circular section having a
diameter equal to the side of the square.
The real condition of the metal under stress is undoubt-
edly always intermediate between the two cases above taken,
the metal near the centre resisting as a solid shaft strained
within the elastic limit at its outer bounding surface, while
the external portion acts as a hollow shaft strained through-
out beyond that limit. Assuming the latter to be strained to
the maximum throughout, and taking r^ rt as the radii of the
two parts, the total resistance would be
* First shown by Prof. Jos. Thomson (Cam. and Dub. Math. Jour., Nov.,
1848 ; Ency. Brit., Art. Elasticity, pp. 798-9, 1883) ; his paper was not dis-
covered by the Author until he had himself determined the facts experimentally,
had reconstructed the theory as above, and had applied it, further, to the case of
bent beams, as in Art. 161, and in Part II., Arts. 262-3, 277.
2/O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
If ae and ar are the angles of torsion at the elastic limit of
the piece and at the beginning of rupture or of flow,
and
If ofe— ar, M= $7rsr3, as already shown for brittle sub-
stances. When af = o, as in absolutely inelastic materials,
did such exist, or when ar = oo , as with perfectly ductile sub-
stances, M — \7tsr*, as already deduced for substances capable
of unlimited flow.
When the torsional moment is given, the diameter of a
shaft in inches is given by Molesworth as
in which
d = diameter in inches.
/ = lever-arm in inches.
P— twisting effort in pounds.
VALUES OF K.
Wrought iron 1,700
Copper 380
Tin 220
Gun bronze 460
Brass 425
Lead 170
167. The Tenacity of Copper varies very greatly with
physical and chemical modifications of structure and com-
position. In the ingot, if pure, it is generally stronger than
in masses re-cast, as it is peculiarly liable to injury by the
absorption of oxygen, the production of " blow-holes," and
the formation of oxide. Rolled and forged copper are
STRENGTH OF NON-FERROUS METALS.
271
stronger than ingot metal. They are made from well-fluxed
ingots and are strengthened, like all rolled or forged metals,
by working. Drawn copper is still stronger, and its strength
increases as the wire is smaller.
Major Wade * found the tenacity of Lake Superior cast
copper to range from 22,000 to nearly 28,000 pounds per
square inch (1,547 to 1*968 kilog. per sq. cm.), averaging above
24,000 pounds (1,705 kilogs.). Egleston gives the tenacity of
both Lake Superior and Ore Knob (N. C.) copper as above,
30,000 pounds per square inch (2,109 kgs. per sq. cm.).
Anderson f gives the figures for the tenacity of copper,
which, in round numbers, are as below — ordinary copper is
compared with that fluxed with phosphorus :
TABLE XXXIV.
TENACITY OF COPPER.
PHOS.
TENACITY, T.
Lbs. per
sq. in.
Kilog. per
sq. cm.
34.000
19,000
25,000
38,000
45,000
48,000
50,000
2,390
1,336
1,758
2,671
3>i64
3,374
3,515
cast
O.OI5
0.02
0.03
0.04
«
«
The effect of fluxing with phosphorus is here very plainly
shown and amounts to an average increase of tenacity of 4,000
pounds per square inch (2,812 kilogs. per sq. cm.) for each
one per cent, added up to four per cent.
168. Cast Copper. — The following are the records of
tests, made by the Author, of ingot copper and of copper
castings made direct from re-melted ingot:
* Metals for Cannon, 1856.
f Strength of Materials.
2/2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XXXV.
TESTS OF INGOT COPPER.
No. 654 a ; length 5", diameter 0.798" ; sound.
LOAD J LBS.
EXTENSION, INCH.
LOAD ; LBS.
EXTENSION, INCH.
500
O.OOOg
7,000
0.627
1,000
0.0038
8,000
0.941
2,000
O.OOSQ
120
0.0964
3,ooo
0.0137
9,000
0.1507
4,000
O.O2O5
10,000
O.2I22
120
0.0089
120
O.2OO9
5,000
0.0279
12,000
0.3686
6,000
0.0324
120
0-3551
120
O.4O2
13,000
broke.
Tenacity 26,000 Ibs. per sq. inch, original area.
" 1,828 kilogs. " " cm.
" 30,398 Ibs. " " inch, fractured.
" 2,137 kilogs. " " cm. "
No. 654 bt same as above.
LOAD.
EXTENSION, INCH.
LOAD.
EXTENSION, INCH.
500
0.0004
10,000
0.1388
1,000
0.0032
1 2O
O.I3I7
4,000
0.0201
I2,OOO
O.3O2O
120
O.OO37
120
0.2933
7,000
0.0485
14,910
broke.
Tenacity 29,820 Ibs. per sq. inch, original area.
" 2,096 kilogs. " " cm.
" 36,217 Ibs. " " inch, fractured.
" 2, 546 kilogs. " " cm. •
169. Tests of Copper.— The methods of test adopted
by the Author in testing these materials are also illustrated
in the table of results which follow. The figures given ex-
ceed those obtained from similar metal by Major Wade.
STRENGTH OF NON-FERROUS METALS.
273
These records are taken from the records of tests made
for the Committee on Alloys of the U. S. Board.
The tests were made on bars cast from re-melted ingot
copper.
TABLE XXXVI.
TESTS OF CAST COPPER.
No. 30 A.— Material : Lake Superior copper, cast in iron mould.— Dimensions : Length, 5"
(12.7 cm.) ; diameter, 0.798" (2 cm.).
n
IO
W
n
2
2 H
i
~i!
i
LOAD PER SQ
INCH.
P K
< U
M
pi
1
LOAD PER Sq
INCH.
ELONGATIOl
INCHES
i
Pounds.
Pounds.
Inch.
Pounds.
Pounds.
Inch.
400
800
0.0004
.00008
11,000
22,000
0.1605
.03210
1,000
2,000
O.OOII
.00022
12,200
24,400
0.2191
.04382
2,000
4,OOO
0.0022
.00044
14,000
28,000
0.3258
.06510
8 ooo
6,000
12,000
0.0032
.00064
14,400
28,800
0.3448
.06896
6,400
12,800
0.0052
.00104
14,600
29,200
0.3760
.07520
6,800
7,200
8,000
8,800
9,600
9,800
250
10,200
13,600
14,400
16,000
17,600
19,200
19,600
500
20,400
0.0083
0.0132
0.0358
0.0642
0.0942
0.1073
Set 0.095 1
0.1218
.OOl66
.00264
.00716
.01284
.01884
.02146
Broke just as reading was'taken # inch from
A end. Fractured section distorted from cir-
cular form. Three diameters measured 0.737
inch, 0.725 inch, and 0.752 inch.
Tenacity per square inch original section,
29,200 pounds (2,053 kilogs. per sq. cm).
Tenacity per square inch fractured section,
34,790 pounds (2,446 kilogs. per sq. cm.).
02436
No. 525 a ; length, 6" ; diameter, 0.798" ; sound casting.
NO. LBS.; LOAD.
EXTENSION, INCH.
NO. LBS.; LOAD.
EXTENSION, INCH.
3,470
4,240
4.Q20
5.350
0.01
0.02
O.O3
0.04
5,900
6,780
7,220
7,270
O.O7
0.12
0.16
broke.
Tenacity 14,540 Ibs. per sq. inch.
" 1,022 kilogs. " " cm.
274 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
No. 525 b ; size as above ; sound.
NO. LBS.; LOAD.
EXTENSION, INCH.
NO. LBS.; LOAD.
EXTENSION, INCH.
4,000
O.OI
8,100
0.23
4,900
0.02
9,000
0.30
5,100
O.O3
IO,OOO
0.40
6,200
O.II
10,220
broke .
7,550
0.17
Tenacity, 20,646 Ibs. per sq. inch.
1,451 kilogs. " " cm.
No. 57 B.— Material : Copper cast in iron mould.— Dimensions : Length, 5" (12.7 cm.)
diameter, 0.798" (2 cm.).
M
ir,
2 •
M
m
2 \
9
la
h
§!l
2
N
K H
K <->
g2
|i
J§ H J
£2
02
gjS j
Q
2 ^ ***
Q
jr (~4
2 % **
S
M
\
^ tt, m
M
S
M
\
a
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
1,000
0.0004
.0001
17,000
0.0779
.0156
2,000
0.0032
.
.0006
18,000
0.0951
.0190
3,000
0.0064
,
.0013
19,000
0.1142
.0228
4,000
0.0093
.
.0019
20,000
0.1388
.0278
5,000
• 0.0116
.
.0023
240
o 1317
6,000
0.0144
.0029
21,000
0.1702
.0340
7,000
0.0170
.0034
22,OOO
0.2028
. 0406
8,000
0.0201
.
.0040
23,000
0.2444
-0489
240
o 003
24,000
0.3020
.0004
9,000
0.0227
.0045
240
o 2933
10,000
0.0263
.0053
25,0=0
0-3585
.0717
II. COO
12,000
O.O32I
0.0371
.0064
.0074
26,OOO
29,820
Measuring apparatus slipped.
Broke 2 inches from B end.
240
o o 53
Diameter of fractured section. 0.724 inch.
13,000
14,000
15,000
16,000
0.0428
0.0485
0.0554
0.0652
.'0086
.0097
.0111
.0130
Tenacity per square inch, original section,
29,820 pounds (2,096 kilogs. per sq. cm.).
Tenacity per square inch, fractured section,
36,217 pounds (2,546 kilogs. per sq. cm.).
240
0.0583
Records of tests of cast copper, as here given above, ex-
hibit the variable quality of this material, due to its absorp-
tion of oxygen.
These tables illustrate the method of variation of resist-
ance with deformation and with increasing load, and exhibit
the figures obtained in a form which admits of the production
of a strain-diagram.
The method of variation of the diameter of a test-piece,
in tension, along the stretched portion is seen in the follow-
STRENGTH OF NON-FERROUS METALS.
27$
ing record of test of copper fluxed with fluor-spar, a flux
which was expected to give much better results than were in
this case actually obtained.
TABLE XXXVII.
TEST OF CAST COPPER (FLUXED WITH FLUOR-SPAR).
No. 51 B.— Material: Copper, cast in hot iron mould, fluxed with fluor-spar.— Dimensions:
Length, 6.19" (15.5 cm.) ; diameter, 0.798" (2 cm.).
LOAD PER SQUARE
INCH.
ELONGATION IN
6.19 INCHES.
i
ELONGATION IN
PARTS OF ORIG-
INAL LENGTH.
Diameter of fractured section, 0.763 inch.
Tenacity per square inch, original section
pounds (1,437 kilogs. per sq. cm.).
Tenacity per square inch, fractured £
22,353 pounds (1571 kilogs, per sq. cm.).
The following measurements were made
diameter of the piece after breaking :
At fractured section
, 20,440
ection,
of the
Inch.
0.763
°-765
0.766
0.766
0.765
Pounds.
8,000
9,800
10,000
11,400
12,400
15,100
16,200
17,040
18,000
19,400
20,000
O
20,400
20,440
Broke at L"
Inch.
O.OI
0.02
0.03
0.07
O.II
0.17
0.2|
O.2O
0.30
0.36
0.40
Inch.
.00l6
.0032
.0048
.0113
.017!
-C275
• C372
.C258
.0485
.0=81
.0646
% inch from fractured section
i inch from fractured section
2 inches from fractured section
3 inches from fractured section
4% inches from fractured section
5 inches from fractured section
0.700
0.767
0.768
0.768
0.774
6 inches irom iractured section
0.46
> end.
.0710
•0743
The importance of effective fluxing and of skill and care
in melting and casting copper, are well shown by a compari-
son of the figures given above for ingot copper with those
obtained for the several re-cast samples, and even better by
contrasting the figures obtained for the latter with those
to be given for rolled and drawn copper, which may be taken
to represent the most perfect attainable soundness.
Rolled Copper as tested by the Author, in bars pur-
chased in the market, had a tenacity of 32,000 pounds per
square inch and reduced in section 40 per cent. Two samples
from the same bar gave the same figure. Rolled copper has
been tested by a committee of the Franklin Institute * who
* Journal of the Franklin Institute, 1837.
276 MATERIALS OF ENGINEERING— NON-FERRO US METALS.
found that the mean of over 60 experiments gave a tenacity
of very nearly 33,000 pounds per square inch (2,399 kilogs. per
sq. cm.), the variations amounting to from 2 to 5 per cent.
Rolled copper, tested by Bauschinger, exhibited tenacities
varying from 29,000 to 32,000 pounds per square inch (2,663
to 2250 kilogs. per sq. cm.), with a reduction of section, at
fracture, of 30 to 45 per cent.
Several authorities agree on nearly the following figures
for various commercial forms of copper:
TABLE XXXVIII.
TENACITY OF COMMERCIAL FORMS OF COPPER.
LBS. PER SQ.
INCH.
KILOGS. PER SQ.
CM.
24,OOO
1,434
" foreed. .
^4,000
2,1^7
" bolt
36,OOO
2,151
" sheet
36,OOO
2,151
" wire
62,OOO
4,2^2
Major Wade found the tenacity of " L. S." copper used in
making U. S. ordnance to be from 24,000 to 25,000 pounds
per square inch (1,688 to 1,758 kilogs. per sq. cm.), and that of
other brands to be between 20,000 and 21,000 (1,463 kilogs.),
increasing a little with hammering. The density varied
between 8.523 and 8.757, tne higher figures accompanying,
usually, high values of T.
According to Trautwine, the strength of cast copper
varies from 18,000 to 30,000 pounds (1,265 to 2,109 kilogs.), a
range fully confirmed, as above, by the experiments of the
Author. Bolt copper ranges from 25,000 to 40,000 pounds
per square inch (1,758 to 2,812 kilogs. per sq. cm.), and wire
is the stronger as it is drawn finer and harder, to an extent
not yet well settled by experiment.
Wertheim obtained for the tenacity of hard wire 4,100
STRENGTH OF NON-FERROUS METALS.
277
kilogs. per square centimetre of section (58,250 pounds per
sq. in.), with an elongation of 0.0033, and for the same wire,
annealed, 3,160 kilogs. (44,900 pounds), with an extension of
0.003.
Copper steam pipes are sometimes given a thickness
/ = 0.00148 n d + o.i 6,* nearly ;
or, according to some authorities^
t = o.oooi dp + 0.125,
when / is the thickness in inches, n the number of atmospheres
pressure, d the inner diameter, and / the pressure in pounds
per square inch. Feed pipes are a little heavier.
170, Shearing Stresses for Copper and sheet brass are
given by the Ordnance Bureau of the United States War
Department \ as below :
TABLE XXXIX.
SHEARING OF COPPER AND BRASS.
Punching.
PRESSURES.
Circ. hole i in. diam.
DIAME-
THICK-
TER OF
PUNCH.
Brass,
.05 inch
thick.
Copper,
.15 inch
thick.
Iron,
.105 inch
thick.
SHEET.
Copper.
Brass.
Thick-
ness.
Pressure,
Circ. hole
i in. diam.
In.
Lbs.
Lbs.
Lbs.
In.
Lbs.
Lbs.
In.
Lbs.
1.5
8,475
15.996
23,273
• 3
21,248
.615
82,871
1-375
T.25
7i723
6,980
14.57°
13-275
2i,445
19,682
.205
.150
15.542
11,088
.565
.51°
76,962
69,984
«.o
5.45°
II,°73
i6,535
.100
8,461
•445
62,591
9,788
14,778
.404
57,623
.8
• 7
4^332
3.772
8,580
7,827
12,602
11,468
.050
.045
3,646
3,362
5,448
-358
.283
51,382
40,486
.6
• 5
3-267
2,635
6,706
5,507
9.772
7,916
.041
• 034
2,538
4,997
3,73°
.245
.183
35,7!2
27.978
-4
2,183
4,585
6,660
.032
2,212
3,54°
• 145
22,213
•3
1.673
3,435
4.97°
.028
2,964
.104
i6,533
.2
.*• •>
1,110
2,240
3.333
.022
1.544
2,448
.057
9.452
* Ordnance Manual. f Seaton on Marine Engineering.
Ordnance Manual.
2/8 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
SHEARING.
Angle formed by shear-blades, 3 degrees.
Sheet Metals.
IRON.
COPPER.
BRASS.
STEEL, PUDDLED.
Thickness.
Pressure.
Thickness.
Pressure.
Thickness.
Pressure.
Thickness.
Pressure.
Lbs.
I4,020t
14,930$
In.
I.o*
.615
.510
.404
.283
.183
.104
.057
Lbs.
144,000
53.440
39.150
25,97°
«5*7*3
10,390
4,200
2.180
In.
207
238
204
!SO
°9
064
°5
02
Lbs.
11,196
6,007
4,820
3,676
2,200
1, 006
552
"3
In.
• 05
.042
.035
.025
.024
Lbs.
540
423
3^3
220
200
In.
.24
• 24
...
Bolts.
IRON.
COPPER.
BRASS.
Diameter.
Pressure.
Diameter.
Pressure.
Diameter.
Pressure.
Diameter.
Pressure.
In.
Lbs.
In.
Lbs.
In.
Lbs.
In.
Lbs.
1.142
35,410
.697
'3,979
18,460
i. no
29,700
1.040
30,707
.585
.906
13,872
.905
22,386
•945
24,0157
•447
5,543
•775
11,310
• 779
17,976
.812
19,688
.320
3i°93
.635
8,218
.648
11,648
The shearing resistance of copper is usually given in office
hand-books as from 22,000 to 30,000 pounds per square inch
(1,420 to 2,109 kilogs. per sq. cm.). Its value may be taken as
the same as in tension and as subject to the same variations.
The work done in shearing copper is, according to Has-
well, measured, for punched holes, by
W= 96,000 d t,
in which W is the work in foot-pounds, d the diameter of
the hole, and t the thickness of the sheet in inches.
171. Resistance to Compression varies with copper, as
with all ductile and malleable metals, more with variation of
form of test-piece and method of application of the stress
than with the ordinary modifications of composition and of
form produced in manufacture, as ingots, sheets, rods, bolts,
* The cutters were parallel ; the bar 3 inches wide.
t With oil. i Without oil.
STRENGTH OF NON-FERROUS METALS.
etc. The application of a crushing force to a test-piece of
standard size and proportions first reduces it to the barrel-
form, then to that of a flat cheese-shaped mass, and finally to
a sheet of which the total resistance to compression increases
indefinitely as its area becomes greater by flow. The com-
pression stress thus increases from about that required to pro-
duce rupture by tension to that demanded to produce free
flow when the intensity of the stress is a maximum ; and its
total amount is limited only by the area of the sheet pro-
duced. The intensity, C, of resistance to compression is
usually incorrectly stated, without limitation, as about 100,000
pounds per square inch (7,030 kilogs. per sq. cm.) for rolled or
forged, and 120,000 pounds (8,436 kilogs.) for cast copper.
The results of experiments of the Author, presently to be
given, indicate that good cast copper, in cylinders of three
diameters length, will exhibit a resistance which may usually
be reckoned up to a compression of one-half or more, as
C = 145,000 /I/ *' nearly,
Cm = 10,000 e' nearly,
where C and Cm are the resistance to compression in British
and metric measures, and e is the compression in unity of
length, the resistance being reckoned per unit of original sec-
tion. But the volume of the piece remaining practically un-
altered, the section is increased very nearly in proportion to
the compression, and the resistance will thus become
3/7"
C1 = 72,000 4/ ' nearly,
3/y
Cm = 5,000 A/ ' nearly,
when reckoned per unit of area of section actually, at the
280 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
moment, under compression. Thus, for good cast copper,
the intensity of pressure producing flow may be taken as not
far from 75,000 pounds per square inch (5,270 kilogs. per sq.
cm.).
Cast copper under compression gives the detailed results
exhibited in the next tables, as obtained by the Author for
the U. S. Board.
TABLE XL.
TESTS BY COMPRESSIVE STRESS.
CAST COPPER.
No. 30. — Material : Lake Superior copper, cast in iron mould. — Dimensions : Length, 2"
(5.08 cm.) ; diameter, 0.625" (1.6 cm.).
\
-ii
U
26,-
55
O
s* •
i!f
|
5
2 O o
2 &. £
1
W
\\
$ ° 3
K "J
1
ii
d
E
8
0
3
O *" ~
0
1
E
Q
1
_PJ_
Pounds.
Inch.
Pounds.
Pounds.
Inch.
Pounds.
500
0.003
1,630
.0015
12,000
0.162
39,' '4
.0810
1,000
0.005
3,259
.0025
13,000
0.205
42,373
.1025
2,000
0.008
6,5i9
.0040
14,000
0.251
45,633
.1255
3,000
O.OII
9,778
.0055
15,000
0.294
48,892
4,000
5,000
0.014
0.018
13,038
16,297
.0070
.0090
16,000
18,000
0-337
0.422
52,152
58,671
.2110
6,000
7,000
8,000
O.O2I
0.026
0.035
19,557
22,816
26,076
.0105
.0130
•0175
20,000
21,000
22,000
o 510
0-559
0.642
65,190
68,449
71,709
.2550
• 2795
.3210
9,000
10,000
11,000
0.051
0.080
O.II9
29,335
32,595
35,854
•0255
.0400
•0595
Piece removed slightly bent.
Surface wrinkled.
No. 51 B.— Material : Cast copper.
H
I
5 it
a
K
£ss*
|
ST.
ni
"Z
o
o- f
0°2
1
§1
III
K
si
1^
Q
0. OS <
m
Q
3
a
|fc 2
9
S
s fc 5
3
8
1
U
3
8
3
8
Pounds.
Inch.
Pounds.
Pound*.
Inch.
Pounds.
150
.0000
20,000
.6461
65,188
.3230
4,000
.0006
13,038
.0033
22,OOO
• 7295
71,709
•3647
6,000
8.000
10,000
.0089
.0573
. 1560
19,557
26,075
32,595
.0044
.0286
.0780
24,000
26,000
28,000
.7936
.8619
.9258
78,228
84,747
91,260
.3968
.4679
12,000
.2568
39»"4
.1284
3°,»°o
.9783
97,785
.4891
14,000
.3602
45,633
.1801
32,000
1.0308
104,303
•5*54
16,000
18,000
.4489
.55"
52,152
58,671
.2244
.2756
Specimen did not show any cracks, but.
merely flattened down.
STRENGTH OF NON-FERROUS METALS. 28l
Both are tests of cast copper, and their difference illustrates
well its variability in quality as ordinarily cast. With proper
fluxing and protection from oxidation and absorption of air,
the metal should give a uniform and maximum resistance.
Rolled Copper, according to Trautwine, is compressed y&ih
by a load of 103,000 pounds per square inch (7,241 kilogs. per
sq. cm.). Its maximum strength in this direction is not far
from that of cast copper, as above, although its resistance
rises more rapidly as pressure is applied and compression
produced.
172. The Compression of Rolled Copper by Impact
has been determined by the Author while investigating the
efficiency of " drop-presses," such as are used in making
" drop-forgings."
Two drop-hammers of each of two kinds were used in
making the comparison, weighing with dies about nine
hundred and about three hundred pounds respectively, plain.
They were adjusted to fall twenty-eight inches. The lost
work was from 10 to 30 per cent.
The gauges used in measuring the work done by the
hammers were cylinders of pure merchant copper, prepared
for the purpose. They measured :
Size No. 1 2% inches long l^ inches diameter.
" " 2 2 " " .1 " "
" "3 i% " " % •<
Of these, a considerable number were prepared and
divided into three sets ; one for use with each kind of hammer,
and one for testing and standardizing in the testing machine.
The work done by crushing the standards in the testing
machine, to the same extent that companion specimens were
crushed Tinder the hammers, gave a measure of the action of
the latter, and permitted a fair comparison to be made. The
amount of work done in the slowly-acting testing machine,
in producing a given compression, is somewhat less than
where the same effect is suddenly produced, as by a falling
weight ; but this difference is not great and, if it could be
282 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
determined and introduced, would increase the figure here
given for efficiency.
The results of the experiments thus made are exhibited
in the accompanying table, and are also shown in the diagram,
Fig. 7. The final results are given in foot-pounds of work per
pound of hammer, and the unavoidable differences in size are
thus eliminated. The modulus of resistance to compression
is also given.
TABLE XLI.
TESTS OF COPPER BY IMPACT.
WORK OF THE DROP-HAMMER.
WEIGHT OF DROP.
903 Ibs.
319 Ibs.
SIZE OF COPPER
CYLINDER.
2V' x li" diam- i" x 2"
No. i. No. 2-
i" x 2" |" x i\"
No. 2. No. 3.
Area in square inches 1
under compression 1
curves.
(See pla^e.) J
AD E A H I
45-23 45-26
Average, 45 . 34.
ANO ARS
13.75 13-76
Average, i3-75i-
Reduced to work done, )
or inch pounds. \
22,715 22,630
Average, 22,672.
6,875 6,880
Average, 6,877.
Ditto in foot pounds. . . .
Average, 1,884.
Average, 576.
Work done per pound )
of drop in inch >
pounds. )
Average, 25.10
Average, 21.56
Ditto in foot pounds. ...
Average, 2.09
Average, 1.8
Final resistance to )
compression. \
70,000 Ibs.
31,751 kilogs.
35,000 Ibs.
15,876 kilogs.
The final resistance to compression in the testing machine
was very nearly 25,000 pounds per square inch (1,760 kilogs.
per sq. cm.). The method of variation of resistance is well
shown in the accompanying diagram, in which the compres-
sion, in inches, is measured by abscissas, and the total corre-
sponding load in pounds, by ordinates. The curves are nearly
cubic parabolas.
284 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The effect of impact on the tough metals having no
definite limit of elasticity is modified by the velocity of the
striking mass, and by the inertia of the piece attacked, to an
extent, as yet, not fully determined. The experiments of
Kick indicate a considerable increase of total work of resis-
tance, when the piece is deformed in this manner, over that
noted when the compression is produced slowly by steady
pressure. The experiments of the Author also indicate that
this work is the greater, with soft and malleable metals, as
the velocity of action is increased. The real efficiency of the
press, as above, is thus probably somewhat greater than the
figures obtained would indicate.
In the preceding figure, the areas cut off under the curves
by the ordinates in full lines are measures of the work of the
most efficient drop-hammers, while those cut off by the dotted
ordinates give the work of less efficient machines.
173. Copper, Subjected to Transverse Stress, is prob-
ably always to be considered as belonging to the second class
of materials treated of in Art. 161, and as more correctly rep-
resented by the equation £.(p. 260) of Art. 166, than the
usually adopted equations preceding them, i.e.
Ml = R1 \* \dl y dy dx, and Fl = 2 n s, P r* dr,
J o J o J r0
instead of
the former of which, for rectangular bearers and solid shafts,
would become, were T= C,
instead of
STRENGTH OF NON-FERROUS METALS.
285
The values of T and C are not, however, the same, and
the differential expression must be integrated for the two
sides of the bar separately.
Cast copper, tested by transverse stress, when of fair
quality should give figures equal to, or exceeding, those
obtained in the record which follows:
TABLE XLII.
TEST OF BAR OF CAST COPPER.
No. 55.— Material : Copper, cast in iron mould.— Dimensions : Length between supports,
i— 22"; breadth, (5 = 0.985"; depth, d = 0.970."
LOAD.
DEFLECTION.
8
MOD. ELASTICITY.
Q
Q
,
MOD. ELASTICITY.
20
40
80
100
5
140
180
200
5
240
280
320
360
400
5
440
0.0033
0.0075
0.0176
0.0224
0.0337
0.0477
0.0552
0.0674
0.0910
o. 1176
0-1553
0.2057
0.2883
480
500
5
540
580
Ruptured.
580
680
720
800
840
860
Supports
Breakinj
Modulus
0.4088
0-4855
0.8378
O.OOOI
15,792,947 |
13*459,739
13,219,331
0.3619
00095
11,174,068
10,728,725
0.8653
1.46
2-39
2.85
3-23
slid out.
fload,P =
of rupture
10,540,763
9,111,146
Bar bent.
860 pounds.
-^
0.1114
The modulus of rupture for good cast copper should thus
exceed 30,000 pounds per square inch (2,109 kilogs. per sq.
cm.), but may be expected to vary between 20,000 and
40,000 (1,406 and 2,812 kilogs.) with variations in the sound-
ness and quality of the metal.
Rolled Copper, as tested by the Author, when of good
quality and sound, may give values of the modulus of rupt-
ure as high as R = 60,000 pounds per square inch (4,218
kilogs. per sq. cm.), and sometimes exceeds this figure, one
test under the eye of the Author, having given R = 60,900
tfm = 4,281.
286 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
174. The Modulus of Elasticity of Copper is almost in-
variably obtained by calculation from the results of transverse
tests, using the expressions,
for the general case and for rectangular sections, respec-
tively/ when the weight of the bar may be neglected, as is
the case with metal test-pieces, usually. By reference to the
records of tests of cast copper already described (Table
XXXVI., Art. 1 68), it will be seen that this modulus may
vary, with even the variation of light loads, from 10 to 15
million pounds per square inch (703,000 to 1,054,500 kilogs.
per sq. cm.), and the same differences are observable as a con-
sequence of varying quality. The higher values obtained in
any one test are the most probably correct, and it may be
assumed that the modulus of elasticity of copper approaches
15,000,000 pounds per square inch (1,054,500 kilogs. per sq.
cm.), as the metal is obtained in a state approximating purity
and soundness. Usual values are two-thirds to three-fourths
these.
Some authorities give values exceeding the maximum, as
above, by 20 per cent., but such figures are not to be expected
in the ordinary work of the engineer.
Forged and wire-drawn copper, as tested by Wertheim,
gave the following values of this modulus :
KILOGS. PER SQ. CM.
Copper, hard-drawn 1,245,000
" " 1,254,000
•' annealed 1,052,000
1,254,000
or very nearly 18,000,000 pounds per square inch for hard-
drawn, and 20 per cent, less, in some cases, for annealed
wire.
* See Part II., p. 499, § 268.
STRENGTH OF NON-FERROUS METALS. 28;
175. Copper Subjected to Torsion is found to exhibit
the same variation of resistance with quality and physical
structure that has been seen in other methods of test. The
experiments of the Author give values of s^ in the equations
for total resistance, Art. 166, ranging between 20,000 and
40,000 pounds per square inch (1,406 and 2,812 kilogs. per sq.
cm.), the lower figure for cast copper of ordinary soundness,
and the higher for good forged or rolled copper. Thus for
the two cases, it may be assumed that copper shafts will
break under load when
8,000 • ' ™
accordingly as they are made of cast or worked copper, when
the units employed are inches and pounds, or
dm =
when the units are metric.
Copper is seldom subjected, however, to any other than
tensile stresses. It would probably be more correct to
use the expressions in Art. 166 for tough metals than the
above, making the true value of sI = 15,000 to 30,000
pounds.
176. Results of all Tests of Cast Copper made for the
Committee on Alloys of the U. S. Board being collected, re-
jecting all tests of samples known to be defective, the follow-
ing figures were obtained. It will be remembered that these
experiments were made with ordinary commercial metals
melted and cast in the usual way and purposely without
other precaution than is usually taken in every-day foundry
work. Much higher figures, as has been seen, may be at-
tained.
288 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
TABLE XLIII.
AVERAGE OF TESTS OF COPPER.
TRANSVERSE TESTS.
TENSILE
TESTS.
TORSIONAL TESTS.
"8
en
i
'si
'§
Tenacity per
square inch
of—
o
en
O
B
"35
IM
0
l)
^
u*O
>,
*o •
3
rt
U>rt
J^
1
a §
r?
'o
1
a|i
II
i
1
Ii
1i
g'i
r*
i
V
1
£
'i'i
•3
1-
c
o
a -a
8
l=
i-a
•8
be
c
PQ
Modulus o
w
Modulus o
0«
1
i
i
1
"So
5
i
s JJ
jQ
.H
s
Maximum
Torsional
.a
i
w
Extension
Brit. Meas.
765
26,357 0.232
10,076,756
0.0628
93,118
26,817
0.491
118.06
41.79
o-354
0.2630
Metric
348
1,853
0.232
708,396
0.0628
1,625
1,885
0.491
16.4
5-8
0.354
0.263
The composition of these bars of copper was found to be
ANALYSES OF TURNINGS FROM FOUR BARS OF COPPER.
NO. I.
NO. 30.
NO. 53.
NO. 57.
o.om
O.OI4
0.015
0.063
Metallic iron
O O2O
O OIJ.
0.0^5
O.OI4
Metallic zinc
o 014
O.O57
o 016
None.
Metallic lead
Trace.
Trace.
None-
Trace.
Metallic bismuth
None
None.
None.
None.
None.
None.
None.
None.
Metallic antimony . . . . .
None
None
None.
None.
Suboxide of copper
12.086
-i ego
6.710
1.620
Metallic copper . •
87 QOO
06 •? 30
Q-5.2OO
08. T^O
0.005
Carbon
None
100.055
99-995
99.996
100.032
177. The Strength of Tin, as obtained in the market, is
variable with the brand, the purity, the soundness, and den-
sity of the metal, with the temperature and the velocity of
distortion and rupture, and with other variable conditions, as
STRENGTH OF NON-FERROUS METALS.
289
is the strength of copper, but in less degree so far as it de-
pends upon the skill and care of the metallurgist. It is less
subject to injury by the presence of deleterious elements, and
is less liable to become unsound in melting and casting.
Mallet obtained a tenacity of 5,600 pounds per square
inch (3,936 kilogs. per sq. cm.), Rennie about 5,000 pounds
per square inch (3,515 kilogs. per sq. cm.), and the Author
has obtained figures for the U. S. Board, and in other experi-
ments, ranging from 2,000 to 6,000 pounds per square inch
(1,406 to 4,218 kilogs. per sq. cm.) for Banca and Australian
tin of the following composition :
COMPOSITION OF TIN OF COMMERCE.
INGOT BANCA
TIN.
INGOT
QUEENSLAND
TIN.
O.O35
O.O35
Metallic zinc
None.
None.
None.
Trace.
None.
None.
Metallic cobalt
None.
None.
None.
Metallic nickel • «
None
Metallic lead
None.
o. 165
0.006
None.
None.
None.
Metallic copper . .
None.
None.
Metallic tin
00.078
QQ . 7Q4
Matter insoluble in aoua resria . ... .
Trace.
100.013
100.000
In casting tin in iron moulds, a difficulty was met with in
the formation of surface " cold -shuts," producing an irregu-
lar section in bars of otherwise sound condition. Tests made
as above give data as follows :
IQ
290 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XLIV.
TENSION TESTS OF TIN (Bancd).
Nos. 29 A, and 29 B.
M
VO
5 6 •
3
2
~ X
g,
n*S
t/5 *
O M
rs fci ^
si
<S|
p°^
Broke % inch from A end.
.
Q
2
2 K •*!
Diameter of fractured section 0.490 inch
1
1
W
o£5
M
(approximately). The section was very much
distorted, and an exact measurement could
not be obtained.
Pounds.
1,700
Pounds.
Inches.
.025
Tenacity per square inch of original section,
considering 1,400 pounds as the breaking load,
2,800 pounds ^with gradual test) (1,462 kilogs.
o
• ••••
Set 0.15
.025
per sq. cm).
Reduced
to—
1,250
2,500
0.19
.0318
In 2 m.
2,500
0.27
•045
1,400
2,800
0.32
•°533
In 10 m.
2,800
1.70
.2833
975
i,95°
O.OI
.0017
Broke 2 inches from D end.
1,180
1,290
i, 600
2,360
2,580
3,200
0.03
0.09
0.20
.0050
.0150
.0332
Fractured section very irregular, and drawn
out almost to a point. Estimated diameter of
final section 0.300 inch.
2,000 j 4,000
2,100 \ 4,200
Piece extending rapic
0.58
ly and strain
.0963
reduced to —
Tenacity per square inch of original section
(with rapid test) 4,200 pounds (2,953 kilogs.
per sq. cm.).
1,700
3,400
2.58
.4269
TABLE XLV.
Summary-
NO
DIAMETER.
Total elongation-
parts of original
TENACITY PER SQUARE
.INCH.
Elastic limit—
pounds per
square inch.
REMARKS.
rt •
bfl'tj
w <n
O
Fractured
section.
Ij
are
'Z%
O
!.!
P
29A...
aoB ...
Mean..
0.798
0.798
0.490
0.300
o-395
0.2833
0.4269
0.3551
2,800
4,200
3,505
Tenacity of frac-
tured section
doubtful.
The strength per square inch of fractured section is not
given for comparison, as it is not an indication of either the
ultimate or the useful strength of the metals, except they have
but a slight ductility and show no increase of elongation under
continued stress. With ductile metals, the portion of the
S7RENGTH OF NON-FERROUS METALS.
29I
test-piece near the point of fracture gradually narrowed down
as the breaking load was approached, and in most cases this
narrowing, or " necking down," was very rapid just before
fracture. In such cases the beam of the scale dropped before
fracture took place, showing decrease of resistance and de-
crease of stress. The final rupture was caused by some load
less than the maximum. In a few cases, it was possible to
follow the decrease of resistance by balancing the scale-beam,
nearly to the instant of rupture, but the actual load sustained
by the piece at the instant of rupture could never be deter-
mined. The so-called " tenacity per square inch of fractured
section/' found by dividing the maximum load by the area
of section measured after fracture, is no measure of the strength
of the metal.
This peculiar method of drawing down at the part nearest
the section ruptured is
well shown in the figure,
and may be taken as illus-
trative of this action in all
tough, ductile materials.
The influence of variation
of velocity of distortion
will be exhibited in a later
chapter.
Authorities give va-
rious values for the tenac-
ity of other forms of tin,
some of which are given
above. Trautwine gives
for block-tin 4,600 pounds, and for wire 7,000 pounds per
square inch (2,854 and 4,921 kilogs. per sq. cm.).
Tests by Compression, made as above, gave values as in the
succeeding record:
FIG. 8.— FRACTURE OF TIN.
2Q2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XLVI.
RESISTANCE TO COMPRESSION : CAST TIN.
No. 29 C.— Material : Banca tin, cast in iron mould.— Dimensions : Length, 2" ; diametet
0.625".
LOAD.
COMP.
C.
UNIT.
1,250
1,500
1,750
1,850
1,900
2,OOO
2,OOO
0.003
0.012
0.043
0.097
o 158
0.265
0.473
4,°74
4,889
5,704
6,030
6,193
6.519
°,5[9
.0015
.oo5o
.0215
.0485
.0790
.1325
.2365
At 1,850 pounds (no kilogs. per sq. cm.),
the piece was observed to be bulging out
on all sides, but still remaining vertical.
At the end of the test the piece had a slight
bend in one direction, and was increased in
diameter to 0.85 and 0.89 inch in different
parts of the length.
2,200
0.612
.3060
2.300
0.729
7,497
.3645
2,300
0.899
7,497
•4445
With tin, as with copper, and all ductile metals, the re-
sistance to compression per unit of original section increases
indefinitely with progressing distortion, and probably attains
a maximum, as reckoned per unit of momentary sectional
area, when the intensity of stress becomes equal to the resis-
tance to the metal to continuous flow.
Elastic limits are even less well defined with tin than with
copper, and the resistance rises rapidly, at the start, as distor-
tion commences and progresses. Resistance to compression
is stated by Trautwine and Haswell as above 15,000 pounds
per square inch (1,054 kilogs. per sq. cm.).
178. Tin under Transverse Test behaves much like
copper, but it has less strength and even less elasticity. It is
the best representative of the viscous class of metals, and, as
will be seen in the chapter on conditions modifying strength
of the non-ferrous metals, is peculiarly susceptible to varia-
tion of time of loading and rapidity of distortion. Tests of
cast tin made by the Author for the government, as above,
gave data of which the following is fairly illustrative:
STRENGTH OF NON-FERROUS METALS.
TABLE XLVIT.
293
CAST TIN IN TRANSVERSE TEST.
Ko. 29.— Material : Banca tin, cast in iron mould.- -Dimensions : Length between support^
22" ; breadth, 0.993" ; depth, 1.002".
<-
M
<-
1 t
"Z
o £ te
|
0 H' ^
0
J
E
(H
J3 ' •*•
Q ||
Q
i
Q fl
a
0
i
i fcl
a
M
Q
1 i . ^
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
3
0.0008
8oh. in 5111
0.282
0.0032
e
o 265
10
0.0055
85
o'^tio
20
0.0095
• . .
6,734,838
In 10 m
0.840
' ..'.
o
O OOJ.7
0.966
24
30
O.OI2
0.015
\j W*f/
6,218,983
6,039,908
goh. iom.
0
1.199
I •••
35
0.017
IOO
i ^60
0
o 0055
In 5 m.
i.jUU
1 .624
40
0.021
5,583,107
In 20 m.
2.124
o
o 0005
45
0.029
_
no
2.332
...
0
So
0
0.041
o 015.
3,517,648
In 10 m.
8.395
. 1 J
Bar bent and tray reached
bottom of supports.
60
o
0.062
2,750,622 .
Breaking iua.u, no jjuuuus.
70
O.IO4
Modulus of rupture, R = — j-r^(P+ 3) = 3,75°-
2 oa *
o
80
0.218
o 082.
Rm (metric), = 262.9
1,026,751
Crack observed on under side of bar extend-
ing across half its breadth.
Tests of Queensland and Banca tin, compared, stood as
follows :
TRANSVERSE TESTS OF TIN.
A
i
Limit of
.
8
1
<i
elasticity.
|o
v aj
°1
^^iS
§
i
1
MATERIAL.
•" o
rt
*O m| N
"Z3
s
REMARKS.
r^ di
•
_Q
W
^ •
o
fc
rf
•^
be
C
05 1
«
"fil
a
tjV
*3
^
_*^
*3
__^
*
3
z
1
1
a
1
1
1
I
I
i
1
7«j.
Ins
Ins
Wv
^s-
58
Queensland tin . .
Banca tin
22
1.038
1.023
4,559
3.+
4
.267
5,635,593
Bent.
Bent
Mean of 2 bars . .
1
130
4,I5°
....
.270
6,185,210
294 MATERIALS OF ENGINEERING— NON-FERROUS METALS
Queensland tin proved very good, showing a somewhat
greater strength by transverse and torsional test than Banca
tin, but a less strength by tension. The transverse strength
probably appears higher than it should be, both on account of
different methods of test, the Banca tin being tested by dead
loads and the Queensland tin by platform-scale, and on account
of a perceptible flaw in the centre of the Banca bar.
In the test of No. 29, as above, a load of 40 pounds pro-
duced a set of 0.0095 inch, and the elastic limit appeared to
be reached at about 30 pounds. At 80 pounds a crack was
observed on one of the edges on the under side of the bar,
which gradually opened but did not increase in length. At
1 10 pounds the bar sank gradually, the deflection increasing
more than 6 inches in ten minutes. The bar was finally
broken by repeated bending, and showed that the crack above
mentioned was produced by an imperfection in the casting,
about one-fourth of the surface, or that portion in which the
crack was observed, showing radiated lines of cooling and
the remainder the close pasty appearance peculiar to tin rupt-
ured by bending. The crack weakened the bar, and the
final bending was resisted by but little more than three-fourths
of the section.
Major Wade found the tenacity of Banca tin used in mak-
ing U. S. Army ordnance to be 2,122 pounds per square inch
(148 kilogs. per sq. cm.) ; its density was 7,297.
179. The Modulus of Elasticity of Tin is stated by
Tredgold at 4,600,000 pounds per square inch (285,400 kilogs.
per sq. cm.) for cast metal, by Molesworth at same figure
nearly, and is found by the Author to vary up to nearly
7,000,000 pounds (492,000 kilogs., nearly). Some of the
figures obtained are given in the records of transverse tests
of cast tin already referred to.
No values have been found for other forms of this metal.
Tin is, however, probably less affected by the form in which
it enters the market than other common metals, and the
moduli here given may be accepted for general use as sub-
stantially accurate.
180. Tin in Torsion, as tested by the Author, gives
STRENGTH OF NON-FERROUS METALS.
295
figures of which the following, from the Report of the U.
Board, may be taken as fairly representative :
TABLE XLVIII.
TORSIONAL TESTS OF TIN.
Averages of Results calculated from Autographic Strain-Diagram.
ORDINATES
TORSIONAL MO-
\
t*
OF DIAGRAM.
MENT.
i
6
§
^
j
V
oi
MATERIAL.
rt
1
I
a
,6
S
T3
*•"
fl
0
8
o
„
o
.u
o
3
3
•^
.2
£H
a
.a
"o
a
I
6
rt
G
.!J
•g
|
3
|
be
n
I
<u
X
"a;
V
'5
0
£
a
<
1
<
(3
K
Sf. ins.
Degrees.
Ins.
Tns.
Ft.-lbs.
Ft.-lbs.
Ft.-lbs.
58
29
Queensland tin ..
Banca tin
42.78
21.20
691.0
556.8
0.73
0.48
O.22
O.I3
12.75
4.36
5.78
2.9029
2.1975
208.48
105.45
3
4
Mean (British) . . .
Metric ....
32.02
20.6
623.9
623.9
0.61
1.6
O.l8
0.46
12.95
1.8
5-07
0.7
2.5502
156.97
The Queensland tin showed an extraordinary ductility in
the torsional tests, one of the pieces twisting through an angle
of 818 degrees, or more than 2^ turns before breaking. This
represents an elongation of a line of particles parallel to the
axis on the surface of the cylindrical portion of the test-piece
from one inch to 4.57 inches.
The average of all tests of tin is given in the following:
AVERAGE RESULTS OF TESTS OF TIN.
TRANSVERSE TESTS.
TENSILE TESTS.
TORSIONAL TESTS.
1
1
bb
Tenacity per
square inch
i
"c
£
I
j
E
-°
S
of—
*
|
13
^
"o
•
o
*o
|
rt
•o
h
|
of rupture
'§'"
of elasticit
S-s
rt be
I1
§
1 section.
I bo
*i c
1
i torsional
11
•-.S
n of exterk
be
V
rt
o
j3
"3
1
1
i
§
'be
•r
•I
i
§
1
1
1
1
PQ
S
H
§
0
£
H
S
H
H
a
M
130
4,150
.270
6,185,210
.3551
3,130
-476
'2.95
5-07
.392
2.5502
156.97
296 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
181. The Strength of Zinc has been determined by
but few investigators, and, like that of all other useful metals
except iron and steel, is a subject of which comparatively
little is known by the engineer.
Cast zinc is stated to have a tenacity of about 4,000 pounds
per square inch (281.2 kilogs. per sq. cm.), and a resistance in
compression of ten times that amount. Stoney states the
tenacity at nearly 3,000 pounds (211 kilogs.) cast, and Traut-
wine gives for sheet-zinc and zinc wire 16,000 and 22,000
pounds per square inch ( 1 , 1 24.8 and 1 ,546.6 kilogs. per sq. cm.),
respectively. The modulus of elasticity is given by Wer-
theim and by Tredgold at from 12,000,000 to nearly 14,000,000
pounds per square inch (843,600 to 984,200 kilogs. per sq.
cm.), the value being higher for cast zinc. The Author has
obtained much smaller figures.
Pure zinc, like pure tin, is never used alone, by the engi-
neer, for purposes demanding strength and toughness. The
values of the several moduli are given as of interest, how-
ever, and for comparison.
Samples of cast zinc tested by the Author show variable
tenacity, the figures ranging between 4,500 and 6,500 pounds
per square inch (2,847 to 4>253 kilogs. per sq. cm.), or consid-
erably above those given by earlier investigators. All the
zinc thus tested by the Author was very pure, and made from
New Jersey calamine. The effects of varying time and rapid-
ity of strain are observable in zinc, as in tin, and are the same
in kind ; they will be described later.
Zinc is much less ductile than tin.
The resistance of zinc to compression varies with the de-
gree of reduction, and, as tested by the Author, was about
22,000 pounds per square inch (1,547 kilogs. per sq. cm.) when
the compression amounted to one-tenth the original height
of test-piece in pieces three diameters long, and one-half
greater for a compression of one-third. Zinc is weaker under
compression than any copper-zinc alloy.
Zinc has no defined elastic limit, but an apparent elastic
limit in compression was recorded at 5,000 pounds per square
inch (352 kilogs. per sq. cm.).
STRENGTH OF NON-FERROUS METALS.
182. Records of Test of Zinc are given below, as reported
to the U. S. Board.
TABLE XLIX.
TENACITY OF CAST ZINC.
Length, 5"; diameter, 0.798".
LOAD.
TOTAL
EXTENSION.
SET.
. PER CENT.
ELONGATION.
REMARKS.
800
O.OOII
O O2
I 2OO
o 0024
o 02
I 6OO
o . 0034.
O O7
Section o 796''
2,OOO
0.0051
O IO
Tenacity 6 300 pounds
3,OOO
o . 0097
O IQ
per square inch (4 420
4,OOO
0.0157
o. 31
kilogs. per so cm.)
2OO
o 0096
5.OOO
0.0206
O 41
6,OOO
o 0240
o 48
6,300
Broke.
COMPRESSION OF CAST ZINC.
Length, 2" ; diameter, 0.625".
COMPRES-
COMPRES-
LOAD.
SION.
LOAD.
SION.
Total.
Per sq. in.
Per cent.
Total.
Per sq. in.
Per cent.
1,000
3,259
0.15
8,000
26,076
12.15
2,000
6,519
0-55
9,000
29,335
I7-I5
3,000
9,778
1.85
10,000
32,595
20.60
4,000
13,038
3-40
10,000
21.80
5,000
16,297
5-io
10,500*
34,225
24.^0
6,000
19,557
7.20
Resistance fell to
7,000
22,816
10.65
10,000
32,595
33-35
* Continued one minute.
298 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
CAST ZINC LOADED TRANSVERSELY.
LOAD.
DEF.
SET.
E.
REMARKS.
2O
O OIOI
40
60
80
100
1 2O
140
3
0.0171
0.0246
0.0324
0.0424
0.0506
0.0616
O O
6,698,725
6,927,556
6,984,644
6,655,180
6,680.965
6,395,032
Modulus of rupture,
R — 7, 540 pounds per
sq. in. (5,300 kilogs.
per sq. cm.).
Most probable value
160
180
200
Broke.
0.0753
0.0906
o. 1244
5,973,588
5,531,549
1,797,132
Em - 428, 130.
TESTS OF CAST ZINC BY TORSION.
Length, i" ; diameter, 0.625".
NO.
AREA DIA-
ANGLE.
MAX. ORDI-
MAX. MO-
EXTEN. EXTER.
GRAM.
NATE.
MENT.
FIBRE.
21 A
19.63
123°
2.15
37.83
O.2O42
21 C
18.81
129
2.07
36.55
0.2227
21 D
17.24
151
1-95
34-42
0.2955
21 B
18.13
I63
2.15
37.83
0.3380
183. Other Metals than those already described have
been made the subject of very few experiments and the data
obtainable are very unsatisfactory. The alloys of the three
principal non-ferrous metals are made the subject of succeed-
ing chapters.
Lead has a tenacity which is reported by Haswell as :
LBS. PER SQ. IN.
KILOGS. PER SQ. CM.
Lead
cast
I 800
116 5
milled
•5-1 2O
27-I.4.
t«
2, 580
181.4
In compression the resistance is stated to be 7,700 pounds
STRENGTH OF NON-FERROUS METALS.
299
per square inch (541 kilogs. per sq. cm.) and the modulus of
elasticity is given as 720,000 Ibs. (49,350 kilogs.). Wertheim,
however, obtains a value of 21,500,000 pounds per square
inch (175,750 kilogs. per sq. cm.). Trautwine gives, for
tenacity :
LBS. PER SQ. IN.
KILOGS.
PER. SQ. CM.
Lead cast
I 8OO to 2 400
ii6
5 to 168 7
" nine .
I,7OO to 2 240
IIQ
5 to 1^7 ^
pipe
1, 6OO
112 5
" sheet
TC C C
as collated from various older experiments, and a resistance
to compression agreeing with Haswell.
The strength of lead pipe, as obtained in market, has,
when tested, been found variable. The best results noted by
the Author * indicate a tenacity of the metal exceeding one
ton per square inch (2,240 Ibs.; 157.5 kilogs. per sq. cm.).
Comparing the results of a number of experiments to obtain
a value of/ in Clark's formula:
- P
hgR*
= TlogR;
in which T is the tenacity, / the pressure, and R the ratio of
external and internal radii, a mean value of TWSLS found to
be 1.4 tons per square inch (220.5 kilogs. per square cm.).
The minimum value was three-fourths as great. It is prob-
able that a much lower pressure, long continued, would have
burst these pipes.
The thickness of lead pipe is frequently determined by the
rule :
t = 0.0024 n d + 0.2,
in which t is the thickness in inches, n the pressure in atmos-
pheres and */the internal diameter in inches.
* Lond. Engineer ; Nov. 16, 1883, p. 378.
3OO MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Antimony has a tenacity of about 1,000 pounds per square
inch (70 kilogs. per sq. cm.), and bismuth of three times that
amount. Gold is a moderately strong metal, with a tenacity,
cast, of 20,000 pounds per square inch, and of 30,000 in wire
(1,406 to 2,109 kilogs. per sq. cm.). Silver is reported to be
about equally strong (?) in the two forms, having a tenacity
of 40,000 pounds per square inch (2,812 kilogs. per sq. cm.),
according to Baudrimont. Platinum has a strength of from
30,000 to above 50,000 pounds (2, 109 to 3,5 1 5 kilogs.). Nickel,
tested by the Author, exhibited tenacities of from 50,000 to
54,000 pounds per square inch (3,515 to 3,543 kilogs. per sq.
cm.), elongating about 10 per cent. Palladium, tested by
Wertheim, had a tenacity equal to that of nickel. It is ques-
tionable whether any of these metals have a true elastic limit.
184. Wertheim on Elasticity. — Wertheim gives the fol-
lowing as the densities, atomic weights, and products of the
two, and also the tenacities and sound-conductivity of several
metals :
S. G.
AT. WT.
«*'
X
O
c/3
RESISTANCE TO
RUPTURE PER
MILLIMETRE.
Coefficient of elasticity
(Tredgold).
13
c
3
O
VI
«*- 'S
!
C '
.9 o
en ^
C ~
I'll
Lead
11.352
7.285
19.258
10.542
6.861
21.530
8 850
7.788
12.94498
12.43013
6.75803
4.03226
12.33499
3-95695
3-39205
0.8769
0.9907
2.2365
2.2959
O.O22
0.063
0.274
0.341
0.199
• 0.499
0.550
I.OOO
1-45
6. 20
600
3.200
7-5
Tin
Gold
Silver
9.0
Zinc
....
9.600
Platinum
CoDoer . .
38.55
20.000
12.0
17.0
Iron .
He infers a general variation of cohesion with change of
intramolecular distances, and obtains his data from experi-
ments upon fifty-four binary alloys and nine ternary alloys,
among which are found also most of the alloys employed in
STRENG TH OF NON-FERRO US ME TALS. $0 1
the arts, such as brass, pinchbeck, gong-metal annealed and
unannealed, bronze, packfong, type-metal, etc.
These experiments gave the following results :
ist. If we suppose all the molecules of an alloy to be the
same distance from one another, we find that, in general, the
smaller the mean distance, the greater is the coefficient of
elasticity.
2d. The coefficient of elasticity of the alloys agrees suf-
ficiently well with the mean of the coefficient of elasticity of
the constituent metals, some alloys of zinc and copper being
the only exceptions. The only condensations and expan-
sions which occur during the formation of the alloy do not
sensibly affect the coefficient. We can then calculate before-
hand what should be the composition of an alloy in order
that it may have a given elasticity, or that it may conduct
sound with a given rapidity, provided that this elasticity or
this velocity fall within the limits of the values of these same
quantities for the known metals.
3d. Neither the tenacity, nor the limit of elasticity, nor
the maximum elongation of an alloy can be determined a
priori by means of the same quantities as determined for the
metals which compose them.
4th. The alloys behave like the simple metals as to longi-
tudinal and transverse vibrations, as well as elongation.
Wertheim,* experimentally determining the moduli of
elasticity of various metals, under varying conditions, came
to the following conclusions :
ist. The modulus of elasticity is not constant for the same
metal ; whatever augments the density increases it, and re-
ciprocally.
2d. The longitudinal and transverse vibrations give the
same modulus of elasticity.
3d. Vibration gives moduli of elasticity much greater than
those obtained by elongation. This difference is due to the
acceleration of movement produced by liberated heat.
4th. Consequently, sound in solid bodies is due to waves
and condensation, and we may be able by means of the for-
* Comptes Rendus. Vol. 15, 1842.
302 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
mula of M. Duhamel to find the relation of specific heat under
constant pressure to that at constant volume. This ratio is
greater for annealed than for non-annealed metals.
5th. The modulus of elasticity diminishes with the eleva-
tion of the temperature at a more rapid rate than that which
is due to the corresponding dilation.
6th. Magnetization does not sensibly change the elasticity
of iron.
7th. The elongation of rods and bars by the application of
loads affects their densities very slightly. The coefficient of
elasticity should, therefore, vary as little in the different po-
sitions of equilibrium ; and this is, in fact, what takes place, in
so far as the loads do not become great enough to produce
rupture. The law of Gerstner is therefore confirmed by all
the metals of which the particles take a position of equilibrium
after having passed their limit of elasticity.
8th. The permanent alloys are not found intermittently,
but in a continuous manner. By suitably limiting the load
and its duration of action, such permanent elongation as may
be desired can be produced.
9th. No true limit of elasticity exists ; and if no perma-
nent elongation is observed for the first loads, it must be be-
cause they have not been allowed time to act, and because
the rod submitted to the experiment is too short relatively to
the delicacy of the measuring instrument.
The values of maximum elongation and of cohesion also
depend much on the manner of operation. They become
greater the more slowly the loads are increased. It may be
seen from this how arbitrary is the determination of least and
of greatest permanent elongation, and that we cannot found
a law upon their values.
loth. The resistance to rupture is considerably dimin-
ished by annealing. The elevation of the temperature, even
to 200° C., does not greatly diminish the cohesion of metals
previously annealed.
Wertheim's values of the moduli for several metals are,
in round numbers, as follow.*
* " Physique Me'canique."
STRENGTH OF NON-FERROUS METALS.
TABLE L.
MODULI OF ELASTICITY OF METALS.
303
LBS. PER
SQ. IN.
KILOGS. PER
SQ. CM.
Lead
2 5OO OOO
176 ooo
7 7OO OOO
4Q2 OOO
Gold
II 5OO,OOO
808 5OO
IO,OOO OOO
70 'i ooo
Palladium
I7,OOO,OOO
I IQZ) OOO
24 ooo ooo
I 687 OOO
Bischof 's Method of Test to determine the purity and
economic value of metals consists in making strips of a
definite and standard size and subjecting them to repeated
bending. The purer the metal, as a rule, the greater the
number of changes of form required to produce fracture.
Zinc, for example, was found to withstand 100, 54 or 19
bendings accordingly as it was pure zinc, best commercial
spelter or the lowest quality. The ill effect of the introduc-
tion of o.ooooi tin, or of 0.0004 cadmium is perceivable even
more certainly than by analysis.
Metals which do not alter by remelting, as tin or zinc, are
melted in crucibles, with continual stirring and then cast in
ingot moulds, 12 cm. long, 1.3 cm. square at the top and 0.3
cm. square at the bottom, 40 or 50 grammes being taken for
a test, or 60 grammes for lead. The bars thus made are
rolled to the desired thinness, annealed and tested. Metals,
as brass, bronze or copper, which are liable to change in
fusion, are rolled from the commercial form, with repeated
annealing. The strips tested by Bischof were 13 cm. (4 inches)
long, 0.7 cm. (2 inches) wide and of such thickness that they
weigh as follows: Copper, 17; brass, 16; tin and zinc, 15;
lead, 25 ; iron and steel, 12 grammes. They were tested in a
" metallometer," in which they could be bent conveniently to
any angle. Repeated flexure and reflexure through an angle
of 67^ degrees was found best adapted to bring out the
quality of the metal. Ten strips were tested simultaneously,
304 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and fifty tests were usually made of each metal, occupying
from an hour to an hour and a half. The following are some
of the results :
(l.) ZINC. — NUMBER OF BENDINGS OF CHEMICALLY PURE ZINC — IOO.
ri l-i
cug
•3 M^
IOO parts chemically
.
a-S §
S
pure zinc alloyed
^
»H C O
*S
with
1
T3
2^*|
.
'a
G*
H
"I
U
I
^3
1
1
5.0 parts
J8
$
so
o
4.0
76
S 1J
3.0
Or^-j
"O T3*
93
73
•o^
2.0
fi JO
Ji2
77
•3 s
. .
1.0
rd'§
28
95
61
QjS
0.5
3
i
91
54
52
0.25 ....
d
o
u
IOO
61
59
95
0.10
53
29
. .
64
64
89
0.05
57
35
. .
69
62
97
0.025 —
57
. .
83
60
0.0125
45
82
70
, .
0.00625 ....
63
t .
85
75
. .
0.003125 —
58
. .
92
90
0.0015625 ....
69
f .
94
88
0.00078125 ....
90
. .
91
93
0.00039062
85
85
. .
0.00019531
84
. .
. .
0.00004382
89
0.00001095
93
• •
• •
• •
The numbers of bendings of about 25 different kinds of zinc from the market
were found to lie between 54 and 19.
(2.) TIN. — NUMBER OF BENDINGS OF BANCA TIN — TOO.
IOO PARTS OF BANCA TIN ALLOYED WITH
LEAD.
ANTIMONY.
2O
•2Q
2e "
2O
j.6
I0 "
*V
qc
6d
72
O O^ "
8d
The numbers of bendings of 4 kinds of Banca tin, obtained through different
sources, were respectively 100, 101, 88, and 78.
STRENGTH OF NON-FERROUS METALS. 305
(3.) LEAD.— NUMBER OF BENDINGS OF M M M MECHERNICH EXTRA— IOO.
IOO PARTS OF M M M ALLOYED WITH
TIN.
ANTIMONY.
CT
2.5 " .
C.A
oc
87
*
O.I "
Ql
IOO
The numbers of bandings of 4 different brands of lead from the market were
found between 100 and 89.
185. Aluminium, according to Mr. A. E. Hunt,* gives
the following :
FORM.
RED. OF
AREA.
POUNDS PER SQUARE INCH.
Elastic Limit.
Tenacity.
Modulus
Elasticity.
Cast
O.IO
.25
.40
.20
5,000
12,000
16,000 to 30,000
10,000
15,000
24,000
30,000 to 65,000
28,000
11,000,000
15,000,000
15,000,000
15,000,000
Thin sheet
Small wire
Bars
In compression the elastic limit is found at about 3,500,
the ultimate resistance at 12,000. The modulus of resilience
is O.l6 to O.22. In shearing it ranges from 12,000 to 16,000,
about equal to pure copper. Specific gravity varies between
P.. 5 5 and 2 65. [See Appendix.]
Further, are given the following :
MATERIAL.
WEIGHT
PER CU. FT.
TENACITY,
LBS. PER SQ. IN.
LENGTH OF BAR,
SUSTAINING ITSELF.
Cast iron .... .
A A A
1 6 ooo
ear ft
Gun bronze ..... ... .
525
31 ooo
Q 80^
\Vrought iron.
480
50 ooo
15 ooo
Al. sheet
165
26,000
23.OOO
168
55,000
39,615
cast . .
160
15 ooo
1 3 ^21
forged
165
20,000
I7,7OO
Its conductivity is high, it is non-magnetic, sonorous, and
exceedingly malleable. It has many valuable alloys, and is
much used in iron and steel castings to confer soundness.
* Jcur. Franklin Inst., Feb., 1891 ; May, 1892.
CHAPTER IX.
STRENGTH OF BRONZES AND OTHER COPPER-TIN ALLOYS.
186. The Bronzes — under which name are included the
principal alloys of copper and tin, and a few special composi-
tions— vary, in strength, elasticity, ductility and hardness, with
variations of composition to such an extent that they find
application in an immense number of the engineer's construc-
tions, their character and chemical constitution being adjusted
to his needs. The most common of these alloys is " gun-
bronze," which consists, usually, of 90 parts copper, 10 of tin,
or 89 copper, 1 1 tin. Such bronze has a strength which will
depend greatly on the soundness of the castings and purity
of the constituents of the alloy, but which often may exceed
50,000 pounds per square inch (3,515 kilogs. per sq. cm.) in
tension.
Bronze used for journal-bearings in machinery is made
harder or softer, according to pressure sustained, the com-
position approaching usually that of gun-bronze, and ranging
from copper, 7; tin, i; to copper, II, tin, i; i.e., copper,
87.5; tin, 12.5, to copper, 91.67; tin, 8.33. A little zinc
or lead added slightly softens it. Packing rings for steam
engines are made of still softer and more ductile bronze —
copper, 92, to copper, 96. These alloys have been very fully
described elsewhere, and this chapter is devoted entirely to the
consideration of their strength, ductility, elasticity and density.
187. Gun-bronze, according to the "Ordnance Manual,"
should have a tenacity of 42,000 pounds per square inch
(2,826 kilogs. per sq. cm.), and a specific gravity of 8.7.
In Major Wade's report on " Experiments on Metals for
Cannon," 1856, are given records of a number of tests of gun
metal.
Specimens of metal from 83 " gun-heads" (the upper part
STRENGTH OF BRONZES. 3O/
of the casting is always deficient in strength) gave an average
result of 29,655 pounds per square inch (2,085 kilogs. per sq.
cm.), the highest figure being 35,484 and the lowest 23,529
pounds. This alloy was copper, 9; tin, I.
Small bars made of gun metal gave higher figures. One
set of 16 bars gave an average result of 42,754 pounds (3,006
kilogs. per sq. cm.), and another similar set an average of
41,284 pounds (2,902 kilogs. per sq. cm.), the lowest figure of
the 32 specimens being 23,854 pounds and the highest 54,544
pounds. Five of the specimens gave more than 50,000 pounds
(3,515 kilogs. per sq. cm.), and only three less than 30,000
pounds (2,109 kilogs. per sq. cm.).
The average of 12 gun-heads was one-half that obtained
from the small sample bars cast with the guns.
A sample of very inferior quality fell below 18,000 pounds
(1,265 kilogs. per sq. cm.).
Major Wade found the quality of bronze ordnance enor-
mously irregular and uncertain, and considered it very im-
portant that a more reliable method of manufacture should
be found.
The tenacity of gun-bronze thus depends greatly upon
the method of manufacture, of casting, and of cooling. By
careful handling it has been given a tenacity, in ordnance,
exceeding, even, 60,000 pounds per square inch (4,218 kilogs.
per sq. cm.), and the Author has obtained small bars still
stronger. Bronze ordnance of large size has been made here
and in Europe with success ; it is, however, very liable to be
irregular in composition and physical character, and the un-
certainty always felt in regard to its condition is an element
which enters into the question of its use for any purpose.
Continual use of ordnance is thought to lead to a separation
of the tin from the copper, and to final destruction. The
gases of powder sometimes corrode the metal badly.
The Modulus of Elasticity of gun-bronze is given by Tred-
gold at 10,000,000 pounds per square inch (703,000 kilogs. per
sq. cm.), and this figure is confirmed by the experiments of
the Author as given later, but it is subject to great variations
with the condition of the metal.
308 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Gun-bronze has less elastic resilience, and therefore less
capacity for taking up shock without permanent deformation,
than has good wrought iron, but more than gun-iron ; it wears
more seriously than iron, and the finished gun is considerably
more expensive, nowithstanding the comparative ease with
which bronze can be worked. It is, therefore, not used very
extensively for ordnance, and is less generally used than for-
merly, when steel was less easily obtained for this purpose
and was more costly than at present. The use of bronze
ordnance will probably, in time, cease entirely.
188. Anderson's Experiments on copper-tin alloys, ap-
proximating to the composition of gun-bronze, give the fol-
lowing results, the tenacity being given to the nearest round
numbers :
TABLE LI.
TENACITY OF ORDNANCE BRONZES.
TENACITY, T.
LBS. PER SQ. IN.
KILOGS. PER SQ. CM.
29,000
31,000
33,000
38,000
2,039
2,116
2,130
2,165
" gi-7 ' " 83
" 01 * " 0
" 00 ' " 10 .
189. Bell-Metals. — Mallet, testing harder alloys, approach-
ing bell-metal in character, obtained as results the tenacities
given below :
TABLE LII.
TENACITY OF BELL-METAL.
TENACITY, T.
LBS. PER SQ. IN.
KILOGS. PER SQ. CM.
Copper, 84.29
82.81
81.10
78-97
30,OOO
34,000
40,000
31,000
2,530
2,390
2,8l2
2,116
" 17 IQ
" 18 GO ..
" 21 0-*
STRENGTH OF BRONZES.
309
190. Gun-bronze in Compression was tested by the
Author with the following results :
TEST OF GUN-BRONZE.
No. 1252. — Copper, 90; tin, 10 ; length, 2"; diameter, 0.769".
Fluxed with mercury sulphate ; sound.
LOAD J LBS.
COMPRESSION, INCH.
LOAD; LBS.
COMPRESSION, INCH.
30,000
32,000
34,000
0.6460
0.6904
0.73H
36,000
38,000
0.7914
0.8115
Resistance, max. 123,860 Ibs. per sq. inch, original area.
8,707 kilogs. " cm. " "
Compression, in per cent., 40.57.
No. 1252-2 ; as above.
LOAD J LBS.
COMPRESSION, INCHES.
LOAD J LBS.
COMPRESSION, INCHES.
10,000
15,000
2O,OOO
o . 0609
0.2IIO
O. 35QQ
25,000
28,OOO
23,500
0.5092
0.8o62
Max. resistance, 92,894 Ibs. per sq. inch.
6, 5 30 kilogs. " cm.
Compression, 40 per cent.
Gun-bronze under compression behaves as exhibited in the
accompanying table.* The resistance at 10 per cent, com-
pression averages about 40,000 pounds per square inch (2,812
kilogs. per sq. cm.) ; at 50 per cent, about 140,000 pounds
(9,842 kilogs.).
* Construction of Artillery, Mallet
310 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
I.
AL TO
TABLE
ONZE GUN
\
j jj- • . . I0>0 • \O • 10 «0 10
o
5 * * '
2
Z
< en 0 ^N.^....QQ.io.oOfO
fc _Q 81 M M . M ... . §NQ • ON . N 10 rn
O
2
< . g
3 ^ ^^5- ^ : : : : 3^ ^ :$>$. R
* ^ S- J?;^^ 5 : : : : 3-1^ " ^^
1
O O .iO« iO OOO VO .NiO
g Lr) *u"> O^fOtx .M« IH xofs.txvo •O'-'N
8
H
Q
y.
< _
w8 NCOI^ONQO'Ti
_Q 10 M t>.^- Tf H O H \
•j •• MWN N NNW
S "
H
^ 2
B 3l
W3 Q t^OO H IO IOWH ON ONO "^" *O O^OO ^
"^ o o5 0*^0 ^o "^ N o5 N ft "^fi ^ N g "^ ^
•J 10 •
IT
o'o S 6S5 0 Ooo
-, w ......
U £ Th^-t>-N MMMN HH\0 OOmtXVO
fc" ^ ON IO W ON H -*d-\O t^ txMCO O VOCMr^ IO
ONOOVON 10 Hioov N Or^O ON
N VOfOrO ^ ONO^H O I^\O t^ NO
a
s
I
^mr ) <JCQU
STRENGTH OF BRONZES.
These experiments were made by Col. Wilmot, R.A., at
Woolwich Arsenal, at the request of Mallet, in 1856. Nos.
i, 2, and 3' were from the " runner " cast with a " 24-pounder "
howitzer. No. 4 was from the cascabel of a similar piece of
ordnance. The test pieces were two diameters long, 0.5 inch
by i inch (1.27 by 2.54 cm.).
191. Hardness of Bronzes. — Riche tested the hardness
of copper and bronze with an apparatus producing an in-
dentation by the blow of a drop or hammer falling upon a
steel punch.
The hardness of bronze increases very rapidly with the
proportion of tin, and the following is the average of many
experiments with the apparatus above referred to :
Impacts necessary
in order to ob-
tain a depres-
sion of —
Copper 19 7
Bronze of 97 parts copper 23 8 to 9
Bronze of 96 parts copper 27 10
Bronze of 95 parts copper 38 14
Bronze of 94 parts copper 40 15
Bronze of 90 parts copper Did not succeed
i with 70 blows.
After these experiments, medals were struck at the mint
in Paris. The differences, which are unimportant for medals
less than 35 millimeters, become more noticeable when the
dimensions attain to 50 millimeters diameter. There are
necessary in this latter case —
With pure copper 7 compressions.
With bronze of 97 parts copper 10 compressions.
With bronze of 96.5 parts copper 12 compressions.
With bronze of 96 parts copper 13 to 14 compressions.
WTith bronze of 95 parts copper 16 to 17 compressions.
Alloy of 95 copper, 4 tin, i zinc 14 compressions.
Alloy of 94 copper, 4 tin, 2 zinc 16 to 18 compressions.
3 1 2 MA TERIA L S OF ENGINEERING— NON-FERRO US ME TALS.
From which he concludes that bronze of 96 and 97 pef
cent, copper may be employed to great advantage and with
no serious inconvenience in the manufacture of medals. Its
hardness does not much exceed that of copper; it possesses
sonority and casts well, rolls evenly, and its color is more
artistic than that of copper. The action of the press and of
heat modifies its density but little.
The hardness and brittleness of speculum and bell-metals
are such as to forbid the use of this method of testing them.
192. " Phosphor Bronze " exhibits much greater strength
and ductility than the same metal cast without phosphorus.
The following tables exhibit the data obtained by various
experimenters and by several methods of test, as collated by
Dick.* They show great strength and remarkable toughness.
TABLE LIV.
TENACITY OF PHOSPHOR-BRONZE— (Kirkaldy).
PULLING STRESS
ULTIMATE
EXTENSION
NUMBER OF TURNS
PER SQUARE INCH.
IN PER CT.
IN 5 INCHES.
Hard.
Annealed.
Annealed.
Hard.
Annealed.
Copper • • • •
63 122 Ibs.
37,002 Ibs.
T.A. I
86.7
06
81,156
51,550
36.5
14.7
C7
Charcoal iron . •
65 8^4.
46 1 60
28
48
8?
Coke iron
64,^21
61,204
17
26
44
Steel
120,076
74,637
lO.q
f
79
Phosphor-bronze No. I .
do do No. 2.
159.515
151,119
58,853
64,569
46.6
42.8
13-3
15-8
66
60
do do No. 3.
i39»J4i
54,ui
44-9
17-3
53
do do No. 4.
120,950
53,381
42.4
13
124
Elastic stress per
square inch.
Ultimate stress
per square inch.
Ultimate permanent
extension in per
cent.
Phosphor-bronze No. I . . .
do do No. 2. . .
do do No. 3. . .
Ibs.
55,200
40,500
26,300
Ibs.
73,987
63,653
54,060
per cent.
3-2
9.4
31-3
* Journal Franklin Institute, 1879.
f Of the 8 pieces of Steel tested, 3 stood from 40 to 45 turns and
STRENGTH OF BRONZES.
TENACITY OF PHOSPHOR-BRONZE — (Uckdtius).
3*3
Specimens.
Absolute resistance
in kilogs. per square
centimetre.
Elastic resistance
in kilogs. per square
centimetre.
Stretch in per
cent.
Phosphor-bronze No. o.
do do No. oo.
Krupp Cast Steel
kilogs.
3,600
5,66o
5,000
kilogs.
600
3.800
1. 000
per ct.
20.66
i. 60
11.00
TENACITY OF PHOSPHOR-BRONZE ( Wohkr).
Tests by Repeated Application of Direct Strain.
PHOSPHOR-BRONZE.
ORDINARY GUN METAL.
Tensile stress
Number of efforts
•vr_
Tensile stress
Number of efforts
per square in.
until rupture.
per square in.
until rupture.
I
10 Tons.
408,350
I
10 Tons.
j Broke before total
\ stress was applied.
2
I2i "
147,850
2
10 "
4,200
3
7i "
3,100,000
3
7* "
6,300
Tests by Repeated Bending in the same Direction.
PHOSPHOR-BRONZE.
ORDINARY GUN METAL.
No.
Tensile stress
per square in.
Number of bends
until rupture.
No.
Tensile stress
per square in.
Number of bends
until rupture.
I
2
3
4
10 Tons.
9 "
74 "
6 "
862,980
4 Million ) J
• •• r|
i
2
3
10 Tons.
7? "
102,650
150,000
837,760
A bar of hammered phosphor-bronze, under 12 tons per
square inch, without breaking, stood more than 2]/2 million
turns, whilst according to Wohler's experiments, a bar of
Krupp cast steel under 12 tons, broke after 879,70x5 turns, and
another bar of the same under 13 tons, broke after 1,007,550
turns.
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
193. The Resistance to Abrasion of the Phosphor-
Bronzes has been found such that Dr. Kunzel has adopted
them, with the addition of a little lead, for the " brasses " of
railway axles. The liquation occurring often results in the
production of two alloys, intermingled, the one a hard, tough,
strong metal which acts as a sponge, retaining the softer
alloy very uniformly diffused throughout its mass. Kunzel
considers that a good axle-bearing should not be homo-
geneous, but must consist of a tough metal skeleton, the
hardness of which should nearly equal that of the axle, and
which should resist any pressure or shock without changing
its form ; the pores of this skeleton should be filled with soft
alloy. The nearer the hardness of the skeleton bearing
approaches the hardness of the axle, the better this skeleton
will resist pressure ; and the softer the metal which fills the
pores, the more excellent is the bearing. Such a bearing is
obtained by using a compound of two or more metals of dif-
ferent tempers and melting points, and in such proportions
that necessarily by cooling a separation of the metals into
two parts or two different alloys of definite composition
results. Bearings of phosphor-bronze alloyed with lead con-
sist of a tough and homogeneous skeleton, the hardness of
which may be regulated to nearly equal the hardness of the
axle, whilst its pores are filled with a very soft alloy ; the
wearing part of such bearings may, therefore, be considered
as consisting of a great number of small bearings of soft
metal, each of which is surrounded by metal of nearly the
same temper as the axle ; Ktinzel's particles of soft alloy
may be easily discerned. When this alloy is heated to a
dull red, the soft alloy exudes, whilst a hard sponge-like
mass forming the skeleton of the bearing remains. Herein
consists the advantage of bearings of these alloys, the axle
running partly on a very soft metal, whereby heating is
obviated, whilst the harder part of the bearing — its skeleton
— checks the wear of the softer metal. The following table*
shows the result of a series of experiments on such bearings.
* Poly 'tech. Centralblatt, Jan., 1874.
STRENGTH OF BRONZES.
315
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a,
-.
pj
•li
•9
0
0
0
o
^
2
OH
1
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
194. Manganese Bronze is another valuable alloy. That
used in the construction of torpedo boats for the British
navy was supplied under a contract calling for a tenacity of
26 to 31 tons per square inch (4,094 to 4,882 kilogs per sq.
cm.), and an elongation of 20 per cent.
This sheet bronze was from -^th to ^th inch (0.16 to 0.32
cm.) thick (No. 9 to No. 18 B. W. G.), and sustained 29 to 30
tons (4,567 to 4,725 kilogs.), stretching 25 to 35 per cent., and
bending cold to a radius equal to their thickness.
Manganese bronze, tested at the Royal (British) Gun Fac-
tory at Woolwich, England, by tension, gave the following
figures, as reported to the Admiralty :
TABLE LVI.
TENACITY OF MANGANESE BRONZE.
(Sheet Metal ; Rods and Bolts.)
NOS.
LOADS
ELONGA-
TION.
Yielding.
Breaking.
Tons per Kgs. per
Tons per
Kgs. per
Per
sq. in. sq. cm.
sq. in.
sq. cm.
cent.
'4,766
4,767
14.0
12.6
2,204
1,984
24-3
29.0
3,817
4,567
8.7
31.8
Cast in metal mould.
D i tto and forged.
4,768
4,769
4,77°
14.0
13.2
16.8
2,204
2,079
2,645
22.1
28.8
23.6
3,480
4,535
3,7*7
5-5
35-3
3-8
Ditto.
Ditto and forged.
Cast in metal mould, slight flavtf
in specimen.
4,77i
12.0
1,890
30-3
' 4,772
25.7
Cast in metal mould and forged.
ROLLED RODS.
6,536
II. 0
1.732
29.0
4,567
44.6
Mild, for ships' bolts and rivets.
6,545
16.6
2,615
30-7
4^35
20.7
High, for Engineers' bolts,
pump rods, etc.
6,546
6,547
14.6
34-4
2,299
S,4i7
30.0
39-6
4,725
6,237
26.2
ii. 6
Medium.
Cold rolled.
AREA OF SPECIMENS, O.I33 INCH. LENGTH OF BREAKING PART, 2 INCHES.
f 7,364
13.8
28.57
4,504
28.7
Pulled in direction of fibre.
8 £365
14.06
2,205
28.46
J3S
Across fibre.
Jl 7i36g
S 7,372
I 7.374
14.06
14.8
16.7
2,205
2,331
2,630
30.13
30.78
3o.i
4,740
4,850
4,74°
II
With fibre.
Across fibre.
With fibre.
STRENGTH OF BRONZES.
317
Manganese bronze, tested by transverse stress, has been
found to possess great strength, flexibility, and toughness.
The following are figures given the Author by the inventor,
as obtained by tests made in presence of the Inspector to the
British Admiralty, January, 1881 :
TABLE LVII.
TRANSVERSE STRENGTH OF MANGANESE BRONZE.
[Length, i foot (0.3 m.) ; Section, i in. (2.54 cm.) square.]
LOAD AT MIDDLE OF BAR.
Elastic Limit.
At Rupture.
Manganese Bronze
Gun (Copper-tin) Bronze
Lbs.
2,688
1,232
Kgs.
122
56
Lbs.
6,048
2,912
Kgs.
275
132
195. Manganese Bronze tested by Impact, resisted the
blow as shown in the following table, furnished the Author
by the inventor :
318 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
2
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STRENGTH OF BRONZES.
319
The wrought iron was of three grades ; the gun-metal
was partly (Nos. I, 2, 3), of usual good quality, and partly
(Nos. 4, 5) specially made for the test of copper, 16, tin, 2, and
copper, 16, tin, 2*^. The manganese was of several grades.
No. 6 was annealed.
196. Copper and Iron, in the proportions varying from
copper, 93. 5, iron, 6.5, to copper, 96, iron, 4, was tested by M.
Riche,* and the alloy compared with copper, as below,
TABLE LIX.
TENACITY OF FERROUS COPPER.
Elongations in millimetres corresponding to loads in kilogrammes.
NAME OF METALS.
«g
OH ^
ni
"i
94
95
in
98
92
92
97
8co
1,000
1,100
1,200
1,300
1,400
1,500
1, 600
1,700
Copper of commerce, melted .
Copper of commerce, rolled. .
Pure copper, melted
Pure copper, melted
0
0-5
1.25
2-5
0.25
0.25
°-5
3-o
5-°
0.25
0.25
3
° 5
tif
0.25
0.25
5
o.S
5-5
(t)
°-5
o.o
o.S
0-5
0.5
0.5'
Copper and iron, melted
Copper and iron, melted
Copper and iron, melted ... .
2
2
4-5
0.25
0.25
0 75
0.50
1-5
2.0
2-5
3.0
(§)
3.5
3-5
Pure copper rolled
1-5
Copper and iron rolled
4-5
NAME OF METALS.
*j
i, 800
1,900
2,000
2,100
2,200
2,300
2,400
2,500
2,600
2,700
2,800
Copper of commerce,
melted
Copper of commerce,
rolled
o.S
o.S
i.S
2-5
4-5
5-5
....
....
....
....
....
Copper and iron, melted.
Copper and iron, melted .
Copper and iron, melted.
Copper and iron, melted.
Pure copper, rolled
Pure copper, rolled
Copper and iron rolled
2
2
4-5
4-5
4-5
5-5
0.25
7.0
2.5
8(j?
10. 0
12.5
15.0
0.25
12.0
16.00
1.0
1.20
1.75
2.5
4.0
0.25
°.5
0.25
J.5
2.0
3-0
4.0
4-5
8.75
8.0
* (Ann. de Chim. et de Phys., 4 strie, t. xxx., Nov., 1873, 26.)
f The test was arrested because a blowhole was formed in the sample.
\ The broken section presents blowholes.
§ At i, 600 kilogrammes one lug of the piece was broken.
U The sample broke without the two pieces being entirely separated.
320 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
NAME OF METALS.
Per
ct.
2,900
3,000
3,100
3,200
3i3QO
3,400
3,500
3,6-o
Breaking load.
a.
tf
jjST
C/3
jj,
'3
1
Copper of commerce,
melted
Kilog.
Kilog.
Copper of commerce,
rolled
Pure copper, melted
1,300
1,000
11.711
10 204.
8.039
Pure copper, melted ....
Copper and iron, melted
Copper and iron, melted
Copper and iron, melted
Copper and iron, melted
Pure copper, rolled
2
2
4-5
4-5
2,400
26.086
2,800
2,300
2,300
28.865
28.220
25 842
8.879
8.904
Pure copper, rolled
Copper and iron, rolled.
Copper and iron, rolled .
4-5
o 25
o 5
0.5
I.O
2.5
2.5
4-75
30.772
40.000
8.891
4-5
0.25
0.75
i. 5
3-5
9.0
3,600
OBSERVATION.— The melted copper (Nos. i, 3, 4) contains blowholes which destroy its
tenacity. It elongates under light loads, and breaks, also, under a small load. The copper
acquires a certain tenacity by rolling. While the resistance of melted copper is from 10 to 12
kilograms per square millimetre, that of the same copper attains, by rolling, 25 to 28 kilo-
grams. The ductility is less, and the elongation becomes no longer evident under loads of
i, 800 kilograms.
finding a decided gain of strength and hardness with no loss
of malleability. The same metals subjected to the action of
a punch, were indented in the proportions, cast copper, 2.5 ;
rolled copper, 1.5 ; with 0.03 iron, cast, 1. 1 ; rolled, 0.9.
197. The Copper-Tin Alloys, which, as has been stated,
furnish a very large number of the best bronzes and engi-
neers' compositions, and which are extensively used in every
department of construction and the arts, had never been sys-
tematically studied until the investigation was made by the
U. S. Government Board upon a plan prepared, proposed,
and carried out at the request of that Board, by the Author.
Earlier investigations had been confined to a few familiar
compositions, and it was only when appropriations made by
the Congress of the United States could be applied to such
a research that it became possible to determine the method
of variation of strength, elasticity, and ductility, and of spe-
cific gravity, and other properties, with variation of compo-
sition throughout all the possible proportions of copper and
tin alloys. In the research to be described the principal as-
sistant employed by the Author was Mr. William Kent
S TRENG TH OF BRONZES. 3 2 1
This investigation of the strength, ductility, and other
properties of all alloys of copper with tin was made in the
Mechanical Laboratory of the Stevens Institute of Technol-
ogy, in the years 1875-1878, for the Committee on Alloys of
the United States Board appointed to test the useful metals
of the United States, and the facts and data here to be given
are mainly condensed from the reports made to that board *
and the notes taken by the Author. This work was supple-
mented by private investigations, of which an account will
also be given.
The intention in the work here to be described was, not
to determine the character of chemically pure metals, melted,
cast, and cooled with special precaution, but to ascertain the
practical value of commercial metals, as found in the markets
of the United States, melted in the way that such alloys are
prepared in every foundry for business purposes, and cast
and otherwise treated in every respect as the brass-founder
usually handles his work; and to determine what is the prac-
tical value, to the brass-founder and to the constructor, of
commercial materials, treated in the ordinary manner and
without any special precaution or any peculiar treatment.
The result was the complete exploration of a broad and
most important field of which almost nothing was previously
known.
The whole field having been explored the useful alloys
are proven to occupy but a limited portion of its great ex-
tent, and it has been now shown that a comparatively narrow
band, extending from ordnance-bronze, on the one side of this
triangular territory, to Muntz metal, on the other, contains
all of the best of the generally useful alloys. This small por-
tion of valuable territory having been pointed out and de-
fined, its more minute study was left for future investigators.
The reader should make a careful study of the graphical
* Executive Document 98, 45th Congress ; Ex. Doc. 23, 46th Congress, 2nd
Sessions ; 1878-1881. In the text of the report will be found a statement of the
more important facts determined, and the tables appended contain all the results
of observation. The whole forms a collection of facts that will probably repay a
vastly more complete analysis and more careful study than it has yet been pos-
sible to give them.
21
$22 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
representation of the results of the research on the alloys, as
presenting most completely and satisfactorily the character,
istics of the metals used.
The researches consisted of an investigation of the proper-
ties of the alloys of copper and tin, cast in the form of bars
about 28 inches (71.1 cm.) long and I inch (2.54 cm.) square
in section, prepared from the commercial metals, only ordi-
nary precautions being taken to secure good castings. It was
desired to learn also the laws which connected these proper-
ties with the proportions of the component metals, and
whether alloys mixed in simple proportions of the chemical
equivalents of the component metals possessed advantages
over other mixtures.
198. The Metals used were the best Lake Superior cop-
per and Banca tin ; they had the following compositions:
INGOT LAKE SU-
PERIOR COPPER.
INGOT BANCA TIN.
O.OI3
O.O^
None.
None
0.014
None.
None
None.
None
Metallic cobalt .. .. ....
None.
None*
Trace
None
None.
Metallic tungsten . ... .... .......
QQ 42O
None.
•$. ^
None.
QQ . Q78
o. Z.V1
0.041
Matter insoluble in aqua regia
Trace
100.025
100.013
199. Alloys Tested. — The following table gives the com-
position of the alloys made, according to their atomic pro-
portions and percentages of original mixture, and according
to chemical analysis after test.
STRENGTH OF BRONZES.
323
TABLE LX.
ALLOYS OF COPPER AND TIN. — FIRST SERIES.
Composition by Original Mixture and Analysis*
NUMBER.
ATOMIC PROPOR-
TION.
PERCENTAGE BY
ORIGINAL MIX-
TURE.
MEAN PERCENT-
AGE BY ANALY-
SIS.
u
E
u >
££
en >
sl
s
8.487
8.564
8.649
8.694
8.669
8.681
8.740
8.565
8.932
8.938
8.947
8.970
8.682
8.560
8.442
8.312
8.302
8.182
8.013
7.948
7-835
7.770
7-657
7-552
7.487
7-360
7-305
7.299
7-293
Cu.
Sn.
Cu.
Sn.
Cu.
Sn.
j
I
96
48
24
0
i
i
i
i
I
i
I
5
i
7
2
3
5
i
4
5
2
3
4
5
12
48
96
I
100
98.1
96.27
92.80
9O.OO
86.57
80.00
76.32
7O.OO
68.25
65.00
6l.7I
56.32
51.80
47-95
44-63
41.74
39 -2C
34-95
28.72
24-38
21. 18
15.19
11.84
9.70
4.29
I. II
0.557
0
o
1.9
3-73
7 20
10.00
13-43
20.00
23.68
30.00
31-75
35-00
38.29
43-68
48.20
52-05
55-37
58.26
60.80
65.05
71.28
75.62
78.82
84.81
88.16
90.30
95-71
98.89
99-443
IOO
2
97-89
96.06
92.11
90.27
87-I5
80.95
76.64
69.84
68.58
65.34
62.31
56.70
51.62
47.61
44.52
42.38
3-37
54-22
25-85
23-35
20.25
15.08
11.49
8.57
3.72
0.74
0.32
1.90
3-76
7-80
9-58
12-73
18.84
23-24
29.89
31.26
34-47
37-35
43-17
48.09
52 14
55-28
57-30
61.52
65.80
73.80
76.29
79 63
84.62
88.47
91-39
96.31
99.02
99.46
a. .
4
6
12
7
8 o
6
10
4
ii
12
3
12
2
12
3
4
6
i
3
3
i
I
I
I
I
i
I
o
14. .
1C
16
17. .
18
IQ
2O
21
22
2-3. .
24
2* . .
26
27
28
20. .
324 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
SECOND SERIES.
NUMBER.
COMPOSITION OF
ORIGINAL MIXTURE.
MEAN COMPOSITION
BY ANALYSIS.
MEAN
SPECIFIC
GRAVITY,
Copper.
Tin.
Copper.
Tin.
qi. .
97-5
92.5
87-5
82.5
77-5
72-5
67-5
62.5
57-5
52.5
47.5
42-5
37-5
32.5
27-5
22.5
17-5
12.5
7-5
2.5
2-5
7-5
12-5
17-5
22.5
27-5
32-5
37-5
42-5
47-5
52.5
57-5
62.5
67-5
72.5
77-5
82.5
87-5
92 5
97-5
99.09
94.10
88.40
82.72
77.56
72.89
67-87
62.42
57-87
53.46
47.27
43.99
37-10
30.76
26.62
22.10
16. 70
11.68
6.05
2. II
0.87
5-43
n-59
17-33
22.25
26.85
32-09
37.48
42.05
46 54
52.72
55-91
62.90
69.19
73-18
77.58
83-23
88.25
93-77
97.68
•3.2 .
8.684
8.647
8.792
8.917
8.925
8.907
8.956
8.781
8.643
8.445
8-437
8.IOI
7-931
7-9T5
7-774
7-690
7-542
• 7-419
7-343
<iA
oe .
•16*
•37
38. .
qo
4O
41 . .
42
4-3 .
45
46
48
4Q .
200. Temperatures of Casting. — The following are the
temperatures at which some of these alloys were poured
into the ingot-moulds. They vary irregularly, but show a
general decrease from a maximum for alloys richest in cop-
per to alloys containing most tin. These temperatures are
evidently not those of fusion of the several alloys, but are
somewhat above in all cases, and are several hundred degrees
above the melting points, usually. The determination was
made by pouring a small portion of molten alloy into a
known weight of water, noting the rise in temperature of the
latter, and, from it, calculating the loss of temperature of
the alloy.
* Second casting ; first broke in emery planer.
STRENGTH OF BRONZES.
325
TABLE LXI.
ESTIMATED TEMPERATURES OF CASTING.
COMPOSITION BY
j
J
TEMPERATURES OF
|
CALCULATED RELA-
ORIGINAL MIX-
H
Ki
WATER, CENTI-
u
TIVE TEMPERA-
TURES.
£
s,
GRADE SCALE.
Sfl U
TURE.
NUMBER.
u.
ft
<j
i
O
a
o
o
- H
X
O
1
i
3
i
9
S
•i-S
d
v *J
§
0
H
i
5
£
I
1
£ g
Ubc
I*
Gram.
Grant.
3X; ' •
97-5
2.5
907
74
8.3
22.8
14.5
0.094177
1909.9
3469-8
32* . .
92.5
7-5
907
101
12.8
31.7
18.9
0.092231
1871.9
3401.4
33- • •
87.5
12.5
907
149
16.7
42.8
26.1
o . 090285
1802.6
3276.6
34- • •
82.5
17-5
907
362
9-4
60.0
50.5
0.088339
I495-I
2723.0
P. . .
77 5
22.5
907
225
15.0
47 3
32-3
0.086393
1554-5
2829.2
. .
72.5
27-5
907
157
11.7
33-3
21.6
0.084447
1511.8
2751.8
37- •
67.5
32.5
907
97
ii. i
26.1
15.0
0.082501
1726.2
3148-8
38. .
62.5
37 5
907
177
10.6
3J-7
21. 1
0.080555
J373-9
2503-4
39- •
57-5
42.5
907
129
17.2
32.8
15.6
0.078609
1428.0
2602 . 4
40. .
52.5
47-5
907
214
8-3
26.7
0.076663
1511.1
2751.8
41. .
47-5
52-5
907
216
12.2
50-5
38.3
0.0747^7
2205 . o
4001.0
42. .
42.5
57-5
907
328
9-5
47-2
37-8
0.072771
1063.8
1945.4
43- •
37-5
62.5
907
293
13-9
38.9
25.0
0.070825
1131.7 | 2067.8
44- •
32.5
67-5
907
255
8.9
32.2
2.3-3
0.068879
1756.9 3192.8
45- •
27-5
72.5
907
85
7.8
18.3
10.5
0.066933
1701.6 3093.8
46. ..
22.5
77-5
907
277
12.2
38.9
26.7
0.064987
1382.7 2519.6
47. ..
17.5
82.5
907
241
15-5
37-2
21.7
0.063041
1331.1 | 2427.8
48. ..
12.5
87.5
907
104
14-4
22.7
8-3
o.o6'ogs
I2II.9 22II.8
49- ••
7-5 92.5
907
240
I8.5
33-3
14.4
0.059149
956.5
1752.8
50- ••
2.5
97-5
907
154
20.5
27.2
6-7
0.057203
725.3
1337-0
The test-pieces were usually cast in iron moulds to secure
rapid cooling.
201. External Appearance of the Bars. — The following
were characteristic features of the bars after casting :
(i) A regular gradation in color took place from bar No.
I, all copper, down to No. 8, 76.64 copper, 23.24 tin, the pol-
ished surface of which was light golden yellow, and a regular
gradation in hardness, No. 8 was filed with great difficulty.
* In casting bar No. 32 (94. 10 copper, 5 43 tin), while pouring the metal into
water for the temperature test, an explosion took place which broke the wooden
vessel holding the water, and threw water and metal about with great violence.
No. 30 was cast at a dazzling white heat. On pouring a small portion into
water to obtain the temperature, a severe explosion took place, and this was re-
peated every time that even a drop of the molten metal touched the water. After
the metal remaining in the crucible had cooled considerably, it could be poured
into water without causing explosions.
It might be supposed that the result of casting at high temperature would be
to make No. 30 a bad bar, as this seems to be indicated by the experiments of
Major Wade on gun-metal. The result, however, showed the contrary, as it
proved to be equal to any bars cast.
326 MATERIALS OF ENGINEERING-NON-FERROUS METALS.
(2) A sudden change of all properties took place at bar
No. 9 — 69.84 copper, 29.89 tin. This bar was silver-white in
color, and could not be scratched with a file. Pieces broken
off showed a conchoidal fracture. No. 10 — 68.58 copper,
31.26 tin — was similar to No. 9, and No. n — 65.34 copper,
34.47 tin — but little different.
(3) Another change of color and properties occurred at
No. 12 — 62.31 copper, 37.35 tin — which bar was of a dark
bluish-gray color, and the fracture similar to that of granite
or other hard rock. This was the most dense alloy of the
series. No. 13 — 56.70 copper, 43.17 tin — was similar to No.
12, but lighter in color and a little softer.
(4) Bar No. 14 — 51.62 copper, 48.09 tin — was peculiar in
showing a marked difference in the two ends of the bar. The
upper end was like bar No. 12, while the bottom was of a
lighter color, granular fracture, and so soft that it could be
cut with a knife like a piece of chalk.
(5) A change between bars No. 14 and No. 20 — 25.85
copper, 73.80 tin — occurred gradually, the bars becoming
whiter and softer, and the appearance of fracture changing
from rough and stony to crystalline or granular. No. 20
could be cut with a knife, giving a short chip which had
slight cohesion. From No. 20 to No. 29 (all tin) the soft-
ness increased gradually, No. 21 giving a malleable chip on
being cut. From No. 24 to No. 29 the appearance of all
bars was much the same, differing slightly in hardness, and
scarcely at all in color.
No. I to No. 8 were likely to prove of value where strength
was required, and bars No. 9 to No. 18, inclusive, were de-
ficient in ductility as well as in strength, and for all practical
purposes (except, perhaps, extremely limited use for special
purposes, as speculum metal) worthless,
Nearly all of the bars appeared to be good castings.
202. The Behavior of the Alloys under test was care-
fully observed and a journal kept. Thus when tested by
transverse stress :
Bar No. 7 (80.95 copper, 18.84 tin), the strongest of the
series, showed little ductility, breaking after a deflection of
STRENGTH OF BRONZES. $2?
half an inch. From No. 8 to No. 13 (23.24 to 43.17 tin) in-
clusive, there was a regular and rapid decrease, both in strength
and ductility, the latter being the weakest bar of the series,
showing only about ^Tth of the strength of No. 7 and a de-
flection of only 0.0103 inch. This bar gave trouble in cast-
ing by breaking in the mould. Bar No. 9 (69.84 copper,
29.89 tin), which, in appearance, differed remarkably from
No. 8 (76.64 copper, 23.24 tin), had less than fths of its strength
and less than Jth of the strength of No. 7, which latter differed
only 10 per cent, from it in composition by original mixture,
or 1 1 per cent, by analysis. Bars No. 14 to No. 20 (48.09 to
73.80 tin) inclusive, showed irregular variation in strength
and ductility, but all of them were worthless, the best having
only about |th of the strength of the maximum, and a deflec-
^tion of only 0.123 inch before breaking. Bar No. 21 (23.35
copper, 76.29 tin) showed considerably greater strength and
ductility than any of the series between No. 8 and No.
20, and greater strength than any from No. 8 to No. 29 (all
tin), giving what may be called a second maximum point of
strength in the series. This bar had a cavity extending
throughout nearly its whole length,
No. 21 to No. 24 (76.29 to 88.47 tin) had higher strength
than those above and below them in series, showing that the
second maximum point of strength is approached by bars
having a difference of over 10 per cent, in composition. From
No. 25 to No. 29 (91.39 to loo tin) there was a somewhat ir-
regular decrease of strength but a great increase of ductility,
bar No. 29 (all tin) showing the maximum ductility of the
series and a second minimum in strength. Bars No. 26 to
No. 29, inclusive, bent without breaking, as did those from
No. 2 to No. 6(1.90 to 12.73 tin) at the other end of the
series.
With reference to the relation of the elastic limit to the
ultimate transverse resistance from bar No. I to No. 7 in-
clusive, the apparent elastic limit occurred at from 35 to 65
per cent, of the ultimate resistance. At No. 8 this limit ap-
proached nearly, if not quite, the ultimate resistance ; and
from No. 9 to No. 18 (29.89 to 61.32 tin) inclusive the two
328 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
coincided, z>., the elastic limit was not reached till the bar
broke. From No. 19 (34.22 copper, 65.80 tin) to the end of
the series (all tin) the elastic limit was again reached before
fracture, the ratio decreasing to No. 22 (20.25 copper, 79.63
tin), and then remaining appreciably constant at from 20 to
30 per cent, to the end of the series.
The relation which the composition bears to the mechani-
cal properties of strength, ductility, and elastic resistance is
thus defined with tolerable exactness.
Bars from No. I to No. 8, inclusive, had considerable
strength, and all the rest were worthless for all purposes
where strength is required. The dividing line between the
strong and the brittle alloys is precisely that at which the
color changes from golden yellow to silver white, viz., at a
composition containing between 24 and 30 per cent, of tin ;
alloys containing more than 24 per cent, tin are comparatively
valueless.
The journals of other tests give very similar records to
those just quoted, and confirm, generally, the deductions which
are made from transverse tests. Of the two bars of copper,
No. i was spongy and weak, as it was cast in sand ; No. 30
was strong and ductile.
In tests by compression, many pieces were compressed to
less than one-half of their original lengths, the resistance to
further compression always increasing. When bending took
place, the piece would, in some cases, take such a position as
to gradually diminish in resistance, the pressure-plates touching
only on the edges of the upper and lower surfaces of the piece.
The actual " crushing strengths" of the ductile metals,
therefore, cannot be stated ; but, for purposes of comparison,
the crushing strength is assumed to be that which corre-
sponds to a compression of one-tenth of the original length.
In the table, therefore, the figures in the column headed
" crushing strength " represent, in the cases of ductile metals,
the loads per square inch necessary to produce compressions
of 10 per cent, of the original lengths.
All brittle alloys, and some possessing limited ductility,
No. 8(76.64 copper, 23.24 tin) to No. 1 8 (38.37 copper, 61.32
STRENGTH OF BRONZES. 329
tin) inclusive, broke suddenly when their maximum resist-
ances were reached, and the figures for crushing strengths are,
therefore, actual values. In these, the " total compressions
produced by maximum load " are the calculated compressions
at the instants of breaking. In other cases, the figures are
total compressions actually given the pieces without breaking
them and include the shortening of the piece by bending ;
they are not the total amounts of compression which might
have been produced had the test been continued further.
By inspection and comparing the results with those of
transverse, tensile, and torsional tests, some important facts
are observed. Assuming that the crushing strength of a
ductile metal is the load necessary to produce a compression
of one-tenth, and that of a brittle metal the load actually
causing fracture, it is noted that the maximum and minimum
strengths are not found in the compositions which exhibited
maximum and minimum strengths by the other methods of
test. It has been observed that the relative strengths of the
alloys, as shown by the other three methods of tes*-y are
similar. This is not the case with compressive tests.
The maximum crushing strength is given by No. 9 (69,84
copper, 29.89 tin), which gave results nearer the minimum
under the other tests. The minimum strength is found in
tin, which was superior to several of the brittle alloys in other
methods of test, which alloys greatly surpassed it in tests by
compression.
The compression pieces, No. I (all copper) to No. 5 (90.27
copper, 9.58 tin), and No. 30 (all copper), give results nearly
alike. From No. 6 (87.15 copper, 18.84 tin) to No. 9 (69.84
copper, 29.89 tin), is a rapid increase. From this point a
decrease takes place to No. 29 (all tin). This decrease is
somewhat irregular. It would be necessary to make a number
of tests before attempting to explain this irregularity, but it
may be a peculiarity of these compositions, since No. 12 was
different in color from both No. II and No. 15, and had the
highest density of the series.
Nos. I to 8 (all copper to 76.64 copper, 23.24 tin), inclu-
sive, were turned in the lathe without difficulty, a gradually
33° MATERIALS OF ENGINEERING— NON-FERROUS METALS.
increasing hardness being noticed, the last named giving a
short' chip, and requiring frequent sharpening of the tool.
The turned surface was perfectly smooth. The color varied
from copper-red to light golden-yellow, gradually becoming
lighter with increase of percentage of tin.
Nos. 36 to 42 (43.99 copper, 55.91 tin) inclusive, were tested
with their original section unaltered, as they were too brittle
to be turned. All gave trouble in setting in the tension machine,
their brittleness and hardness being so great that the grips
of the machine would not firmly hold them. They usually
broke in the grips, and the figures representing strength are
in many cases too low.
203. Surfaces of Fracture. — After the tests by transverse
stress, pieces were cut from each bar showing the fracture.
These pieces were examined by Prof. A. R. Leeds, who made
the following report.
No. I (all copper). — Color, copper-red, altering by ex-
posure to air into purple by film of suboxide, and into black
by film of oxide of copper.
Surface in part large vesicular, in part curvilinear fibrous.
Maximum diameter of vesicles, 7 mm. ; maximum breadth of
fibres, 1.5 mm.; length, 8 mm.
No. 2 (97.89 copper, 1.90 tin). — Color, red, slightly oxi-
dized by exposure. Large and coarse vesicular ; maximum
diameter of vesicles, 5 mm.
No. 3 (96.06 copper, 3.76 tin). — Color, bright reddish-yel-
low, with faint traces of black oxide from exposure. Surface,
small and finely vesicular.
No. 4 (92.11 copper, 7.80 tin). — Color, dull reddish-yellow.
Homogeneous. Surface, finely arborescent.
No. 5 (90.27 copper, 9.58 tin). — Color, reddish-yellow, with
spots of dark red and bright yellow. Surface, not homoge-
neous, in part vesicular, in part finely fibrous.
No. 6 (87.15 copper, 12.73 tin). — Color, brass-yellow in
part, in part bluish-white. Surface, not homogeneous, finely
vesicular. Fracture, hackly.
No. 7 (80.95 copper, 18.84 tin). — Color, reddish-gray, with
brass-yellow spots. Surface, reticulated fibrous.
STRENGTH OF BRONZES. 331
No. 8 (76.64 copper, 23.24 tin). — Color, reddish-gray. Sur-
face, faintly vesicular ; interior of vesicles brass-yellow. Fract-
ure, irregularly curved. Lustre, dull.
No. 9 (69.84 copper, 29.89 tin). — Color, grayish-white. Sur-
face, crystallization prismatic, diverging from centre. Fract-
ure, of large curvature. Lustre, glistening.
No. 10 (68.58 copper, 31.26 tin). — Color, grayish-white,
more white than the preceding. Surface, crystalline pris-
matic, diverging from the centre. Fracture, of large curva-
ture. Lustre, glistening.
No. ii (65.34 copper, 34.47 tin). — Color, bluish-gray, show-
ing yellowish spots in some lights. Surface, interruptedly
crystalline. Fracture, coarsely rounded. Lustre, splendent.
No. 12 (62.31 copper, 37.35 tin). — Color, dark bluish-gray.
Surface, laminated. Fracture, coarse hackly. Lustre, splen*
dent.
No. 13 (56.70 copper, 43.17 tin). — Color, bluish-white.
Surface, crystallization eminent ; crystals prismatic and
diverging from centre. Lustre, splendent.
No. 14 (51.62 copper, 48.09 tin). — Color, bluish-white.
Surface, crystallized, but not readily apparent. Fracture,
coarse angular. Lustre, splendent.
No. 15 (47.61 copper, 52.14 tin). — Color, grayish-white.
Surface, finely granular. Fracture, waved. Lustre, glistening.
No. 16 (44.52 copper,. 55.28 tin). — Color, grayish-white.
Surface, laminated granular. Fracture, coarsely waved.
Lustre, glistening.
No. 17 (42.38 copper, 57.30 tin). — Color, grayish-white.
Surface, crystallization finely reticulated. Fracture, uneven.
Lustre, glistening.
No. 1 8 (38.37 copper, 61.32 tin). — Color, grayish-white.
Surface, crystallized, but not readily apparent. Fracture,
coarse hackly. Lustre, bright.
No. 19 (34.22 copper, 65.80 tin). — Color, grayish-white.
Surface, crystallization eminent, prismatic, and diverging
from centre. Prismatic angle, 130°. Sides of prism doubly
striated, one set of striae parallel to edge of prism, the other
at an angle of 47° with the former. Lustre, splendent.
3 3 2 MA TERIA LS OF ENGINEERING— i\7ON-FERRO US ME 7'ALS.
No. 20 (25.85 copper, 73.80 tin). — Color, grayish-white.
Surface, crystallization eminent, prismatic. Lustre, splendent.
No. 21 (23.35 copper, 76.29 tin). — Color, grayish-white.
Surface, crystallized, but not readily apparent. Fracture,
hackly. Lustre, bright.
No. 22 (20.25 copper, 79.63 tin). — Color, grayish-white.
Surface, crystallization not large but eminent ; prismatic
diverging from centre. Prismatic angle, 107°. Lustre,
splendent.
No. 23 (15.08 copper, 84.62 tin). — Color, grayish-white.
Surface, crystallization, coarse with prismatic faces, divergent.
Fracture, jagged. Lustre, splendent.
No. 24 (11.49 copper, 88.47 tm)« — Color, grayish-white.
Surface, crystallization finely reticulated. Fracture, hackly.
Lustre, dull with bright reflections from scattered crystalline
faces. Section, distorted.
No. 25 (8.57 copper, 91.39 tin). — Color, grayish-white.
Surface, granular. Lustre, dull, with glistening points.
Section, distorted with curved edges.
No. 26 (3.72 copper, 96,31 tin). — Color, grayish-white.
Surface, rounded granular. Lustre, dull.
No. 27 (0.74 copper, 99,02 tin). — Color, grayish-white.
Surface, usually crystallization feeble with undefined pris-
matic faces. Lustre, bright.
No. 28 (0.32 copper, 99.46 tin). — Color, grayish-white.
Surface, irregularly waved. Lustre, dull.
No. 29 (All tin). — Color, bluish or grayish-white. Surface,
slightly vesicular at centre, prismatic at edges. Section,
much distorted. Lustre, bright.
The following description of the fractures by tensile stress
was also recorded :
No. I B (all copper). — Color, copper-red, with a purple
film of sub-oxide ; surface, in part large vesicular, in part
crystalline, radiating toward edge.
No. 2 A (97.95 copper, 1.88 tin). — Color, copper-red ; sur-
face deeply vesicular ; fracture, uneven ; lustre, dull, with
bright points.
Bar No. 2 B (97.83 copper, 1.92 tin). — Color, copper-red,
STRENGTH OF BRONZES. 333
inclining toward yellow ; surface, finely vesicular ; fracture,
uneven ; lustre, dull, with fine bright points.
Bar No. 3 B (95.96 copper, 3.80 tin). — Color, reddish-yel-
low ; surface, finely vesicular, the curved surfaces interrupt-
ing; lustre, dull.
Bar No. 4 B (92.07 copper, 7.76 tin). — Color, yellowish-red
in part, in part reddish-yellow ; surface, vesicular ; lustre, dull.
Bar No. 5 A (90.11 copper, 9.66 tin). — Color, yellowish-
red ; surface, crystallization, fibrous, radiate, finely vesicular
on faces ; lustre, dull.
Bar No. 5 B (90.43 copper, 9.50 tin). — Color, grayish-yel-
ow ; surface, coarse vesicular ; fracture, jagged ; lustre, dull.
Bar No. 6 A (87.15 copper, 12,69 tm)- — Color, bluish-white
with bright yellow spots ; surface, confusedly vesicular; fract-
ure, hackly ; lustre, dull.
Bar No. 6 B (87.15 copper, 12.77 tin). — Color, reddish-yel-
low, with bluish-gray points, producing a general impression
of orange ; surface, broadly crystalline, with surfaces of pris-
matic faces finely vesicular ; lustre, dull, with minute bright
points.
Bar No. 7 A (80.99 copper, 18.92 tin). — Color, grayish-
white with yellow points; surface, not apparently crystalline;
fracture, coarse hackly ; lustre, dull.
Bar No. 8 B (76.60 copper, 23.23 tin). — Color, yellowish-
gray ; surface, vesicular, with smooth intervening faces ; fract-
ure, even ; lustre, shining.
Bar No. 9 A (69.90 copper, 29.85 tin). — Color, yellowish-
gray to bluish-gray in different lights ; surface, broadly-bladed
prismatic, and diverging from centre ; fracture, smooth ; lus-
tre, splendent.
Bar No. 10 A (68.58 copper, 31.26 tin). — Color, yellow to
bluish-gray ; surface, broadly-bladed prismatic and diverging
from centre ; fracture, smooth ; lustre splendent.
Bar No. II A (65.31 copper, 34.47 tin). — Color, yellow to
bluish-gray ; surface, crystallized, but not readily apparent ;
fracture, coarsely waved ; lustre, splendent.
Bar No. 12 B (62.79 copper, 36.96 tin). — Color, blue ; sur-
face, coarsely waved and pitted ; lustre, splendent.
334 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Bar No. 13 A (56.28 copper, 43.11 tin).— Color, bluish;
surface, crystallization eminent, prismatic blades diverging
from centre ; fracture, uneven ; lustre, splendent.
Bar No. 14 A (62.27 copper, 37.58 tin).— Color, bluish-gray
in part, in part reddish-gray ; surface, crystallized but not
readily apparent ; fracture, uneven ; lustre, dull.
Bar No. 14 B (38.41 copper, 61.04 tin)- — Color, bluish-gray ;
surface, crystallized but not readily apparent ; fracture,
coarsely waved ; lustre, splendent.
Bar No. 15 B (47.49 copper, 52.29 tin). — Color, bluish-gray
to grayish white; surface, waved; fracture, irregular; lustre,
glistening.
Bar No. 16 B (44.42 copper, 55.41 tin). — Color, grayish-
white ; surface, crystallized but not readily apparent, waved
and feebly vesicular; lustre, glistening.
Bar No. 17 B (38.83 copper, 60.79 tm)- — Color, grayish-
white ; surface, finely waved vesicular ; lustre, shining, with
bright points.
Bar No. 18 A (43.37 copper, 56.37 tin). — Color, grayish-
white ; surface, crystallization prismatic, with waved lines on
prismatic faces; lustre, splendent.
Bar No. 18 B (43.36 copper, 56.40 tin). — Color, grayish-
white ; surface, crystallized but not readily apparent, feebly
vesicular ; fracture, irregular ; lustre, glistening, bright lines
of reflection from crystalline faces.
Bar No. 19 A (40.32 copper, 59.46 tin). — Color, grayish-
white ; surface, crystallization eminent, prismatic ; the pris-
matic faces large and striated : prismatic angle, 91° ; lustre,
splendent.
Bar No. 19 B (40.24 copper, 59.44 tin). — Color, grayish-
white ; surface, crystallization eminent, prismatic ; lustre,
splendent.
Bar No. 20 A (26.57 copper, 73.08 tin). — Color, grayish-
white ; surface, crystallization eminent, the faces in part
prismatic, in part having an octahedral aspect ; lustre, splen-
dent.
Bar No. 20 B (25.12 copper, 74.51 tin). — Color, grayish-
white ; surface, crystallized but not readily apparent, waved
STRENGTH OF BRONZES. 335
and feebly vesicular fracture, rough ; lustre, glistening, with
bright surfaces of reflection.
Bar No. 21 B (33 89 copper, 75.68 tin). — Color, grayish-
white ; surface, feebly crystalline and vesicular ; fracture,
hackly ; lustre, glistening, with bright points.
Bar No. 22 A (20.28 copper, 79.63 tin). — Color, grayish-
white ; surface, crystallization eminent, prismatic faces irre-
gular ; lustre, splendent.
Bar No. 22 B (20.21 copper, 79.62 tin). — Color, grayish-
white ; surface, confusedly crystalline, with prismatic faces ;
lustre, splendent.
Bar No. 23 A (15.12 copper, 84.58 tin). — Color, grayish-
white, in part with yellow tarnish ; surface, crystallization
eminent, broad prismatic faces, radiate ; lustre, splendent.
Bar No. 24 B (11.48 copper, 88.50 tin). — Color, grayish-
white ; surface, crystallized fibrous ; fracture, hackly ; lustre,
glistening, with bright lines of reflection from edges of crys-
tals.
Bar No. 25 A (8.82 copper, 91.12 tin). — Color, grayish-
white ; surface, irregular and feebly vesicular ; lustre, dull.
Bar No. 26 B (3.74 copper, 96.32 tin). — Color, grayish-
white ; surface, fibrous, in part slightly vesicular ; lustre, dull.
Bar No. 27 A (0.75 copper, 98.98 tin). — Color, grayish-
white ; surface, fibrous ; fracture, jagged ; lustre, dull.
204. Records illustrating the Methods and Results
of this research are given on the following pages, in tabular
form, selected from the mass of data recorded in the reports
of the U. S. Board, to which reference may be made for other
details. Those here given are representative of the work
done on some of the best alloys discovered during the inves-
tigation, but do not by any means include all the useful
compositions, the data from which are included in the table
of summaries of all methods of test there given. These tables
of records cover the range from good bearing metal to bell-
metal, and the figures given are fair averages for such alloys ;
they fall considerably below figures attainable in larger work
performed by trained workmen.
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXII.
TESTS BY TENSILE STRESS.
No. 4 A.— Material: Alloy.— Original Mixture: 92.8 Cu. 7.2 Sn.— Analysis, 92. 14 €0,7.84 So.
—Dimensions: Length, 5"; Diameter, 0.798".
.si .
•Si.
Load.
Load per
square
inch.
Elongation
in 5 inches.
ill
Load.
Load per
square
inch.
Elongation
in 5 inches.
fp
O j-^C
§ g^G
w
S
Pounds.
Pounds.
Inch.
Pounds.
Pounds.
Inch.
5,100
10,200
O.OI
.0020
14,610
29,220
°-37
.0740
8,000
10,000
16,000
20,000
O.O2
0.03
.0040
.0060
"fee
29,300
il inches fro
°-39
tn L end.
.0780
10,760
21,520
0.05
.0100
Diameter of fractured section, 0.730 inch.
11,410
22,820
O.OQ
.0180
No blowholes.
o
11,900
12,800
Set 0.08
O.II
0.14
.0220
.0280
Tenacity per square inch of original sec-
tion, 29,300 pounds (2,090 kgs. per sq. cm.).
Tenacity per square inch in fractured sec-
23,800
25,600
13^4°
26,280
0.21
.0420
tion, 35,000 pounds (2,461 kgs. per sq. cm.).
14,000
28,000
0.27
.0540
No. 7 A.— Material: Alloy.— Original mixture: 80 Cu, 20 Sn.— Analysis : 80.99 Cu, 18.92 Sn.
—Dimensions : Length, 6" ; Diameter, 0.798".
9^850
14,000
16,800
Diamete
One bloi
inch diarru
19,700
28,000
33,600
r of fracture
whole, irregu
:ter.
O.OI
O.O2
Broke in
d section, 0.7
lar-shaped, *
.002
.004
middle.
98 inches.
LDOUt O.IO
Tenacity per square inch original section,
33,600 pounds (2,362 kgs. per sq. cm.).
Tenacity per square inch, deducting blow-
hole, 34,139 pounds (2,400 kgs. per sq. cm.).
No. 33 B.— Material: Alloy.— Original mixture : 87.5 Cu, 12.5 Sn.— Dimensions: Length, 5";
Diameter, 0.798".
1
1,200
0.0025
.0005
24,000
0.0905
.0191
2,000
0.0052
.0010
200
0.0665
3,000
0.0097
.0019
26,000
o. 1040
.0208
4,000
0.0139
.0028
ii8,OOO
0.1271
.0254
6,000
0.0206
.0041
200
0.1063
8,000
0.0275
•0055
30,000
0.1561
......
.0312
200
— o'.oooS (?)
32,000
0.2007
.0401
10,000
o 0330
.0066
2OO
0.1811
12,000
o . 0396
.0079
33,000
0.2270
•°454
2OO
0.0049
33,200
0.2432
.0485
14,000
°-°473
.0094
16,000
0.0541
.0108
Broke in middle.
2OO
18,000
20,000
2OO
0.0623
0.0709
0.0200
0.0421
.0125
.0142
Diameter of fractured section, 0.770 inch.
Tenacity per square inch, original section,
33,200 pounds (2,334 kgs. per sq. cm.).
Tenacity per square inch, fractured sec-
22,OOO
0.0793
.0159
tion, 35,648 pounds (2,508 kgs. per sq. cm.).
STRENGTH OF BRONZES. 337
TABLE LXIII.
TESTS BY COMPRESSIVE STRESS.
No. 31.— Material : Alloy.— Original mixture: 07.5 Cu, 2.5 Sn.— Analysis: 99.09 Cu, 0.87 Sn.
—Dimensions: Length, 2" ; Diameter, 0.625".
C.J.
c i
'" be
•- be
Load.
Compres-
sion.
Load per
square
inch.
Compression
parts of ori
nal length.
Load.
Compres-
sion.
Load per
square
inch.
Compression
parts of ori
nal length.
Pounds.
Inch.
Pounds.
Pounds.
Inch.
Pounds.
15°
.0000
16,000
• 3951
52,152
•J975
2,000
.0018
6,519
.0009
18,000
58,671
.2588
4,000
.0093
13,038
.0046
20,000
'.61*6
65,188
.3078
6,000
.0302
.0151
22,000
.7266
71,709
•3683
8,000
.0609
26,075
• 0305
24,000
.8483
78,228
.4242
10,000
.1077
•°539
25,000
.8801*
81,485
.4100
12,000
.1662
"30 114.
.0831
14,000
.2601
45,633
.1300
* Wedge cracked off at the top.
No. 32.— Material : Alloy.— Original mixture: 92.5 Cu, 7.5 Sn.— Analysis : 94.11 Cu, 5.43 Sn.
Dimensions: Length, 2" ; Diameter, 0.625".
150
.0000
22,000
.4584
71,709
.2292
2,000
.0000
6,5*9
24,000
>5l5l
78,228
•2575
4,000
6,000
.0000
.0002
13,038
19-557
.0001
26,000
28,OOO
.5778
• 6393
84,747
91,266
.2889
•3197
8.000
.0108
26,075
.0054
30,000
.7000
97,780
•3500
10,000
.0511
32,595
.0255
32,OOO
•7499
!04,303
•3749
12,000
.1219
39,H4
.0609
34,000
.8033
110,822
.4016
14,000
•!937
45,633
.0968
36,000
.8447
"7,34i
•4223
16,000
18,000
.2648
•33l°
52,152
58,671
.1324
• 1655
38,000
40,000
.8918
•9330
123,860
130,379
•4459
.4665
20,000
.3951
65,188
.1975
No. 33.— Material : Alloy.— Original mixture: 87.5 Cu, 12.5 Sn.— Analysis :
Sn. — Dimensions : Length, 2" ; Diameter, 0.625".
1.40 Cu, 11.59
TCO
,OOOO
24,000
•32^4
78,228
.1617
15U
4,000
.OOI4
13,038
0007
26,000
• ^31
• 3575
84,747
• • *• /
• 1783
6,000
.0058
T9,557
0029
28,000
.4019
91,266
.2009
8,000
.0170
26,075
0085
30,000
.4412
97'785
.2206
10,000
•0374
32,595
0187
32,000
.4815
104,303
.2407
12,000
.0711
39,TI4
°355
34,000
.5I71
110,822
.2585
14,000
.1166
45,633 -
0583
3*\ooo
— W34-
117,341
.2767
16,000
.1636
52,152
0818
38.000
•5905
123,860
.2952
18,000
.2102
58,671
1051
40,000
.6234
130,379
•3"7
20.000
.2564
65,188
1282
42,000
.6611
136,898
•3305
22,000
.2991
7i,709
1495
44,000
.6911
I43,4i7
•3455
22
33$ MATERIALS OF ENGINEERINGS-NON-FERROUS METALS
TABLE LXIV.
TESTS BY TRANVERSE STRESS.
fJo. 4.— Material : Alloy.— Original mixture : 92.8 Cu, 72 Sn.— Dimensions : Length between
supports, 22" ; Breadth, 0.997" ; Depth, 1.012".
Load.
Deflection, A.
Set.
Modulus of
elasticity.
*-JTS»tf>+4)
Load.
Deflection, A.
Set.
Modulus of
elasticity.
E=— ^73^+4)
4 A £>a3
Pounds.
6
10
20
30
£
80
100
o
125
'5°
175
200
0
225
250
0
275
300
o
325
350
375
400
o
425
450
475
0
500
o
525
550
o
575
0
600
o
-650
0
700
Inch.
0.0008
0.0016
0.0039
0.007
O.OIO
0.013
0.017
O.O2O
Inch.
Pounds.
o
750
800
o
850
900
o
_ 950
In 5 m.
1,000
In 5 m.
0
1,050
Inch.
•173
.199
287
Inch.
0.020
0.049
10,408,413
8,114,620
0.000
13,396,305
-348
-429
.491
-584
.620
781
0.024
O.O29
0.034
0.041
0.045
0.052
0.057
0.059
0.063
0.066
0.072
0.075
0.079
0.082
0.087
0.095
0.102
0.106
O.II2
0.124
°-137
5,267,855
13,680,575
°-379
12,818,227
0.000
1,100
In 10 m.
o
1,100
',150
In 3 m.
1,200
In 10 m.
o
1,200
1,250
In ro m.
In 30 m.
15" 30™
o
1,250
1,300
In 10 m.
In 30 m.
i,35o
In 30 m.
Break
Modu
.858
.03!
•053
• 155
.289
•384
.824
!824
• 935
.178
.281
•637
.638
.746
.911
.966
3.226
6.706
ng load, /
us of rupt
R
Rm*
3,314,847
0.0008
12,583,801
0.807
0.000
13,274,439
2,240,640
13,817,863
1-549
o.ooo
13,877, '97
0.0016
0.0024
14,263,420
I3,677,484
2-343
1,223,372
0.0032
13,464,355
Tray reached bottom of
supports.
'= i, 350 pounds,
are,
-CT^^-48'731'
= 3,074-
0.0055
0.0095
X2*,548,648
o.i53
",853,945
STRENGTH OF BRONZES.
339
TABLE
. — Continued.
No 32. — Material: Alloy. — Original mixture: 92.5 Cu, 7.5 Sn. — Dimensions: Length
between supports, / = 22" ; Breadth, b = 0.956" ; Depth, rf = 0.982".
Load.
|<
Set.
Modulus of
elasticity.
PI*
Load.
Deflection.
A
Set.
Modulus of
elasticity.
/>/•
4A<W3
rrsr«
Pounds.
10
20
40
80
T20
160
200
3
240
280
320
360
400
3
440
480
520
560
600
fcl
Resist
Resist
Inch.
0.0060
0.0104
0.0185
0.0278
0.0376
0.0472
0.0572
o!oo68
0.0769
0.0880
0.0983
o. 1105
0.1232
0.1389
0.1535
0.1719
0.1963
0.2065
ance decre
ance decre,
Inch.
Pounds.
600
±
720
700
800
^
840
880
920
960
1,000
1,040
1, 080
Bar ben
Breakii
of 3*
Moduli
Inches.
0.2095
0.2365
0.2867
0-351*
0.4609
0.6031
Inches.
0.0655
7,957,281
6,030,003
6,357.759
8,401,765
9,384,450
9,967,673
10,281, 341 ^
10,564,538
10,706,500
10,692,594
10,768,738
10,644,211
0.0413
3,900,466
0.0035
o . 6202
0.779^
0.0427
1.3217
'.74
2.13
2.63
3.78
t to a defle<
ig load (or
' j i ,080 poi
s of rupti
0.0145
Beam sinks
1,380,404
10,501,656
10,161,429
9,961,177
9i579,I7I
8,987,663
840,132
3-4?
:tionof 8" w
the load ca
mds.
!«,*=*£
2 OCi
Rm — 2,71
thout breaking,
using deflection
^ = 38,659.
8.
0.0577
ased in 2m to
ised in ih 48'"
586 pounds,
to 562 pounds.
No. 7. — Material: Alloy. — Original mixture: 80 Cu, 20 Sn. — Analysis: 80.95 Cu, 18.84
Dimensions: Length between supports, 22" ; Breadth, 0.998" ; Depth, i.on.
100
I25
'S3
'75
200
0
225
250
275
300
3
325
350
375
400
0
425
450
475
500
o
525
550
575
600
0
625
650
700
0
750
800
o
850
0.025
0.028
0.033
0.037
0.043
0.045
0.051
0.057
0.063
0.069
0.073
0.077
0.081
0.083
0.087
0.094
0.098
0.103
0.105
o. 114
0.122
0.128
0.132
0.140
0.155
0.167
0.172
O.OO24
0.0039
I0,737,827
11,891,996
12,045,639
12,487,468
12,245,726
900
0
950
1,000
o
1,050
o
1,100
I,2OO
0
1,300
0
1,400
0
1,500
0
1, 600
o
1,700
0
1,650
In 15 h
o
1,520
1,750
the lasl
Break
Modul
t>.:84
0.192
0.201
0.209
O.2I9
0.256
0.285
0.320
0.360
0.415
0.470
0.510
0-537
0.469
Broke i
pound of
ng load, i
us of rupti
R = ~h
20
Rm = 3,9
0.0103
12,681,589
0.012
12,893,200
o 013
0.026
0.039
0.055
0.075
0.099
0.126
13,012,118
12,139,743
11,810,161
11,325,050
10,783,714
12,855,428
12,455,356
12,517,091
0.0047
12,874,176
9,976,527
9>355,254
0.0063
13,274,787
9,202,114
0.169
0.0063
12,779,097
D seconds after putting on
the weight.
750 pounds,
ire,
'-j*(p+ 3) = 56,715.
87.
0.0039
12,979,791
0.0063
12.426,896
340 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXIV.— Continued.
No. 33.— Material : Alloy.— Original mixture: 87.5 Cu, 12.5 Sn.— Dimensions : Length be.
tween supports, 22"; Breadth, 0.973"; Depth, 0.977".
Load.
Deflection.
A
Set.
Modulus of
elasticity,
Pfl
^^bd*
Load.
Deflection.
A
Set.
Modulus of
elasticity.
E P*
4AW
Pounds.
10
20
£
120
160
200
3
240
280
320
360
400
3
t
520
560
600
640
680
720
£
842
880
920
960
Inches.
0.0042
0.0075
0.0125
0.0236
0.0322
0.0409
0.0508
Inches.
Pounds.
1,000
3
1,040
i, 080
1,200
1,160
1,200
3
1,200
I,240
1,280
1,300
1,320
1,360
1,400
1,440
1,480
1,520
,560
,600
,640
,680
,700
3
1,700
Bar br
Breaki
Moiul
Inches.
0-3245
Inches.
0.0910
9.337,752
9,969,873
10,603,633
11,478,087
11,549,891
0.3611
0-3959
0-4493
0.5122
0.5727
0^5892
0-6475
0.7485
0.8111
0.8701
0.9892
1.1419
1.3032
1.4878
1.6700
1.8500
2.1000
2.4500
3-1000
3.5000
8,002,946
0.0049
0.2827
6,147,034
0.0606
0.0701
0.0793
11,717,949
11,838,275
11,869,273
IJ, 974,17!
0.0036 (?)
o. 1071
0.1168
0.1255
o-i355
0.1461
12,052,435
3,596,760
12,155,454
12,127,844
12,047,936
2,235,! 79
0.1568
0.1678
0.1800
o.i933
0.2074
o . 2269
o-2475
0.2716
0.2964
11,888,540
slowly.
",3i5,997
Beam sinks
0.0284
1,424,927
2.81
oke after a deflection of about 4".
ng load, 1,700 pounds.
us of rupture, R = „ = 60,403 Ibs.
Rm = 4,246.
9,937,327
No. 34. — Material: Alloy. — Original mixture: 82.5 Cu, 17.5 Sn. — Dimensions: Length be-
tween supports, 22" ; Breadth, 0.950" ; Depth, 0.970".
1 20
160
200
IO
240
280
320
360
400
IO
$
E
600
10
640
680
720
760
800
Resistan
IO
840
880
920
960
0.0316
0.0405
0.0481
0.0560
0.0646
0.0729
0.0804
0.0881
0.0940
0.1027
0.1099
0.1174
0.1265
0.1340
0.1409
0-J473
0-1549
0.1631
ce decreas
0.1702
0.1790
0.1873
0.1959
11,659,056
12,129,260
12,765,982
1,000
IO
1,040
i, 080
1,120
1,160
1,200
1,240
I,28o
1,320
1,360
1,400
IO
1,520
1, 600
IO
1,720
1,800
1,840
Brok<
30 secoi
after re
Breai
Modu
0.2060
0.2157
0.2264
0.2377
0.2472
0.2614
0.2728
0.2852
0.3003
0.3175
0.3330
0.3880
0-4393
0.5247
0.5757
0.6125
: suddenly
ids after pi
ading the c
:ingload, i
lus of rup
0.0098
14,903,838
0.0035
14,802,137
13,158,079
I3,3°7,4I7
I3,476>957
13,747,250
13,939,699
14,371,235
14,349,611
14,526,967
14,644,993
14,562,305
14,466,320
13,495,466
0.0035
0.0436
12,055,389
0.0028
0.0935
10,064,370
14,663,731
14,817,235
15,007,180
15,063,694
^osg^iS
to 788 pounds.
9,223,187
ng sound about
strain, and just
P/
-ji = 67,930.
75-
with a ringi
itting on the
eflection.
,840 pounds.
ture, R = - -L
2 b
Rm = 4,(>
;d in i9h 45ra
0.0047
15,152,664
15,093,815
15,080,625
I5,045,48i
STRENGTH OF BRONZES. 341
205. Final Results. — The following table exhibits the
results of the whole investigation in a compact form which
permits ready comparison of data.
The average results obtained by test of the copper-tin
alloys, enable the engineer to reach tolerably definite conclu-
sions relative to their value in construction. The results are
given as obtained by the four principal methods of stress.
They are very variable, and this variability is due not only
to the variation of composition of the alloys, but also to their
differences of physical structure, and is, therefore, to some
extent, accidental.
General conclusions may, nevertheless, be deduced and
the principal facts revealed by test, and these conclusions
are also most unmistakably exhibited by the diagrams pre-
sented in this and preceding articles.
The figures given by the tests have been plotted in the
form of curves having for their ordinate the resistance ob-
served and for their abscissas the distortion of the given test-
piece. These curves exhibit the method of variation of re-
sistance with progressing change of form, and constitute
" strain diagrams " which exhibit to the eye every important
quality of the material.
342 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
il
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STRENGTH OF BRONZES.
343
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344 MATERIALS OP ENGINEERING— NON-FERROUS METALS
206. Strain-Diagrams, obtained from tests determining
tenacity of the bronzes, are given in the accompanying figure
as derived from experiments upon the first series of copper-
tin alloys, No. I, pure copper, to 29, pure tin, inclusive. The
curves marked A are from the upper end of the bar and B
from the lower end.
These curves may evidently be divided into three classes :
viz., those which are very rigid and brittle, as 7 A, 7 B (cop-
per, 80, bell-metal), those which are very ductile and mallea-
ble but soft and weak, as Nos. 26 to 29 (tin, 95 to 100)
inclusive ; and those which combine strength and ductility
and possess, therefore, great resilience, as Nos. 2, 3 and 4
A (copper, 93 to 98, gun-metals). All intermediate qualities
may be obtained, but these are typical and the most valuable
of these compositions are evidently, for general purposes,
those belonging to the last class, and of which the strain-
diagrams lie between the extreme qualities, one set of which
lie near the axis of abscissas, while the other set lie nearer the
axis of ordinates. For some purposes, as when, for example,
it is desirable to secure a high elastic limit as well as moderate
toughness, alloys like ordnance bronzes, Nos. 4, 5, 6 (copper,
86 to 93), which are stiff and strong, although not very ductile,
may be chosen. Cases may even arise, although certainly
not often, in which the rigidity of bell-metal, No. 7 (copper,
80), may make that alloy valuable in consequence of its
high elastic limit, notwithstanding its great deficiency in
ductility.
207. The Tenacities of the valuable class of these metals
range not far from 30,000 pounds per square inch (2,109 kilogs.
per sq. cm.), the strength increasing somewhat with the pro-
portion of tin up to 18 per cent. Within that range, the
expression
T= 30,000 + 1,000 /,
in which T is the tenacity and / the percentage of tin, may
be taken to represent a maximum which selected materials
STRENGTH OF BRONZES.
345
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and careful fluxing should enable the engineer to secure,
Two-thirds these values, or
T — 20,000 4- 700 /,
should be expected as a minimum. In metric measures, the
two values would become, nearly,
T = 2,100 + 700 /, as a maximum ;
Tm — 1,400 + 500 t, as a minimum.
The ductility should be at least 10 per cent, for the best
alloy, and must be expected to be too slight to be counted
upon when the proportion of tin exceeds 20 per cent, unless
this percentage rises to a very high figure, as from 90 per
cent, upward, when it again becomes considerable.
The modulus of ultimate resilience obtained by multiply-
ing two-thirds the tenacity by the extension of a piece one
unit in length should be, in foot-pounds, for the more
valuable alloys, not less than 3,000 foot-pounds or 250
foot-pounds per cubic inch (or not far from 2.5 kilogram-
metres per cubic centimetre) for good materials, and two-
thirds this value for ordinary work. The elastic resilience is
not to be expected to exceed 5 foot-pounds per cubic inch (or
about 0.05 kilogram-metres per cubic centimetre).
The plate only exhibits one of the two sets of strain-
diagrams, and a less favorable representation of the quality of
these alloys than would be obtained from tests of specially
prepared and carefully fluxed specimens, such as may be
secured when needed.
The alloys containing from 75 down to 25 per cent, copper
are stone-like, inelastic, brittle and worthless for the work of
the engineer, their strain-diagrams are straight lines and do
not appear in the figure.
A moderately well defined " elastic limit" is seen to exist
with many of the harder of these alloys, as, e.g.t Nos. 3, 4, 5
and 6 (copper, 85 to 95).
208. Compression Strain-diagrams are exhibited in
Figure 10 which are obtained from the same set of alloys as
STRENGTH OF BRONZES,
347
34$ MATERIALS OF ENGINEERING— NON-FERROUS METALS.
were used in the preparation of the tension diagrams shown
in the preceding illustration.
The alloys do not hold precisely the same order in com-
pression as in tension ; but the same general facts are
observable. The most resilient (ultimate) metals are as
above, Nos. I to 7 and 30 (copper, 80 and upward) ; the most
malleable are Nos. 25 to 29 (copper, 10 or less), and the most
rigid are Nos. 9, 10, 11 (copper, 65 to 70).
No. 9 (copper, 70) excels enormously in strength and in
elastic resilience, and in elastic resistance ; No, 8 (copper,
75) is a very resilient alloy, also ; Nos. 6 and 7 (copper, 80 to
86) excel in ultimate resilience, or power of resisting shocks
great enough to deform the piece. Gun-bronze, No. 5 (cop-
per, 90), is evidently one of the best of these alloys.
Some of the singular variations seen in several of the
diagrams are probably due to accidental peculiarities of de-
formation of the test piece ; possibly all may be so.
Elastic limits are not as well defined here as in the tension
diagrams, and, in the hard alloys, are either obscure, as in No.
7 (copper, 80), or coincide with the point of rupture, as in
Nos. 9-15 (copper, 45 to 70).
Comparing the two sets of diagrams, it is seen that, for
members in tension, for bolts, sheet metal, ordnance, in fact
for the majority of all common purposes, the best alloys are
those lying very near the copper-end of the series and con-
taining from 2 to 10 per cent, of that metal, and the less as
the method of attack includes the action of shock to a greater
extent. For compression, more tin is advisable (10 to 15 per
cent.) if shock occurs, and it may be justifiable to reduce the
copper to 70 per cent., even if the load is applied absolutely
without jar, and maximum tenacity, simply, is sought.
209. Transverse Tests of the copper-tin alloys give
strain-diagrams such as are seen in Figure 11. Compositions
approaching copper, 80, tin, 20, exhibit the greatest strength
under this form of load.
Those having less tin (6 to 10 per ceni..) as Nos. 4, 5
(copper, 93 ; copper, 90), are evidently vastly better to resist
the shock of suddenly applied loads and safer against accident ;
STRENGTH OF BRONZES.
349
31 I I
3 SO MATERIALS OF ENGINEERING— NON-FERROUS METALS.
while those consisting principally of tin are soft and very
ductile and malleable, as already seen.
210. Comparison of Resistances.— By inspection of the
curves, it will be seen that the curves of tensile and torsional
strength agree very closely, the torsion curve being laid down
to such a scale that one foot-pound of torsional moment has
the same measure as 200 pounds tenacity. The curve of
transverse strength is, in form, similar to those of tension and
torsion (one pound modulus of rupture corresponding to
one pound tenacity), but the ordinates of the curve are usually
much greater than in the two latter.
The curve of compression strength is very unlike either of
the others. Laid down to the same scale as that of tenacity,
the ordinates of the curve are much higher, showing that the
compression resistances of the copper-tin alloys are much
greater than their tenacities. The maximum compression
strength is reached by one of the brittle alloys, the tenacity
of which was not far from the minimum.
The tensile and compressive resistances of the alloys are
in no way related to each other ; the torsional strength is
very nearly proportional to the tensile strength. The trans-
verse strength may depend, in some degree, upon the com-
pressive strength, but it is much more nearly related to the
tensile strength, as is shown by the general correspondence
of the curve of transverse with that of tensile resistance.
The modulus of rupture, as obtained by the transverse tests,
is, in general, a figure between those of tensile and compres-
sive resistance, but there are a few cases in which it is larger
than either, indicating an approach to the condition suggested
in forming the equations already given.
The strength of the alloys at the copper end of the series
increases rapidly with the addition of tin, up to about 4 per
cent. Transverse strength continues to increase up to about
\Jl/i per cent, of tin; while the tensile and torsional resist*
ances also increase, but very irregularly, to the same point.
As this irregularity corresponds to the irregularity of the
curve of specific gravities, it is probably due to porosity, and
might not be seen in sound castings.
STRENG TH OF BRONZES. 3 5 1
The maximum point of the three curves is reached at about
the same point, viz., at the alloy containing 82.70 copper,
17.34 tin.
From the point of maximum strength, the three curves
drop rapidly to alloys containing about 27.5 per cent, of tin,
and then more slowly to 37.5 per cent., at which point nearly
the minimum strength is reached. The compression curve
reaches its maximum between these points. The alloys of
minimum strength are found from 3.75 per cent, tin to 52.5 per
cent. tin. The absolute minimum is probably about 45 per
cent, of tin.
From 52.5 per cent, of tin to about 77.5 per cent, tin
there is a slow and irregular increase in strength to the point
which has been called the second maximum.
From 77.5 per cent, tin to the end of the series, or all tin,
the strengths slowly and somewhat irregularly decrease, the
second minimum being reached at the end of the curve.
All alloys containing more than 25 per cent, tin are prac-
tically worthless for all purposes demanding strength, the
average strength of these alloys being only about one-sixth of
the average of those containing less than 25 per cent, of tin.
Maximum strength is associated with a peculiar color, a
reddish or pinkish gray, which marks the change from the
ductile to the brittle alloys, and occurs between the percent-
ages of tin which give a silver-white alloy in which no trace
of copper could be detected by the eye, and the reddish-
yellow to yellowish-gray alloys like No. 6 (lower end of bar)
and No. 33.
The results of these tests do not seem to corroborate the
theory that peculiar properties are possessed by the alloys
which are compounded of simple multiples of their atomic
weights or chemical equivalents, and that these properties
are lost as the compositions vary more or less from this
definite constitution. It does appear that a certain percentage
composition gives a maximum strength and another certain
percentage a minimum, but neither of these compositions is
represented by simple multiples of the atomic weights.
There appears to be a perfectly regular law of decrease
352 MATERIALS OF ENGINEERING—NON-FERROUS METALS.
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STRENGTH OF BRONZES. 353
from the maximum to minimum strength which does not
have any relation to the atomic proportions.
211. Total Resilience, or the product of the mean resist-
ance into the distance through which the resistance acts, is
the work done in breaking a piece of metal. For tensile stress,
it is equal to the mean resistance multiplied by the total
elongation ; for transverse stress it is the mean resistance
multiplied by the total deflection, and for torsional stress it is
the mean resistance of the specimen as measured by the mean
ordinate of the autographic strain diagram, expressed in foot-
pounds of torsional moment, or pounds acting at the radius
of one foot multiplied by the distance through which this
moment is exerted as measured by the total abscissa of the
diagram, and reduced to feet traversed by the resistance. Its
values are given elsewhere.
The total resilience under transverse stress was calculated
from the curves of deflections by transverse stress, the area
of the curve being directly proportional to the resilience, the
ordinates representing resistances and the abscissas deflec-
tions. The results are reduced to foot-pounds of work. In
the cases of bars which bent to a deflection of more than 3^
inches (8.9 cm.) without breaking, the resilience within that
limit of deflection was taken.
The torsional resilience was calculated from the area of
the autographic strain-diagram and reduced to foot-pounds
of work.
The resilience under tensile stress was not determined.
Referring to the plates of curves of resistances, it will
be found that resilience bears a very close relation to
ductility, the curves being nearly similar, except in those por-
tions of the curves representing the alloys which bent with-
out breaking under transverse stress, and of which the trans-
verse resilience is taken only within a deflection of 3^
inches.
The maximum torsion resilience is given by No. 3 (96.06
copper, 3.76 tin\ one of the most ductile of the strong alloys.
No. 33 (88.40 copper, 11.59 tin) gave maximum transverse re-
silience within the deflection of 35^ inches, being the strong-
23
354 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
est alloy which reached that deflection without breaking, but
its total resilience is less than those of the more ductile bars,
which bent, without breaking, to deflections of more than 8
inches.
From the bar which gave maximum total resilience a rapid
decrease occurs to No. 8 (76.64 copper, 23.24 tin). From No.
8 to No. 20 (35.85 copper, 73.80 tin) all bars, with one excep-
tion, show total resiliences so small, compared with the maxi
mum, that the curve of resilience between these points ap-
proaches the bottom line of the plate so closely that it
apparently coincides with it. The figures for transverse re-
silience agree with those of torsional resilience between these
points.
From No. 20 to No. 28 (0.32 copper, 99.46 tin) there
is a gradual increase of the total resiliences to the " second
maximum."
The alloys which are of most value to the engineer are
evidently those containing less than 20 per cent, tin, and, for
the great majority of purposes, gun-bronze (copper 89.90) and
the alloys containing rather less tin are likely to prove best ;
while those containing from 10 to 15 per cent, tin are evi-
dently to be chosen where hardness, combined with strength,
must be secured. Alloys of these metals containing from 30
to 70 per cent, of either are rigid, brittle, and valueless for
the ordinary purposes of the engineer, although some of them
may have use for special work.
The phenomenon of decrease of set with time was observed
for the first time with -No. 47. On relieving the bar of all
pressure except that due its own weight, and except a very
slight pressure (a few ounces) to insure that the pressure-block
actually touched the bar and was not raised from it, the scale-
beam balanced at 5 pounds, and the reading of the set was
made. While reading the set the scale-beam was observed
to rise, indicating increase of resistance to deflection, as it had
similarly been observed to drop when resistance to stress took
place. A number of observations of this increase of resist-
ance to the permanent deflection were made, and also of the
decrease of set, as measured by running back the pressure-
S TRENG TH OF BRONZES. 355
screw till the scale-beam again balanced at 5 pounds, and
taking additional readings. The result of these observations
showed that in one observation of 39 minutes the resistance
of the bar, as measured by the scale-beam, increased 18 pounds,
and that in 2 hours 20 minutes the set decreased the amount
of 0.0239 inch.
This fact of the decrease of set with time has since been
confirmed by a large number of tests made on the same ma-
chine, and it has also been observed by other experimenters.
It indicates that what has been hitherto called the " perma-
nent set " of metals is in reality not entirely permanent, but
is partially, at least, temporary, a fact already well-known.
212. Specific Gravity. — The curve of specific gravities
(Fig. 13) shows considerable regularity, indicating that the
densities of the alloys follow a definite law.
The alloys containing less than 25 per cent, of tin show
irregular variation in specific gravity due to porosity. The
figures obtained are the densities of castings, and not of the
metals themselves, as they might be determined in fine pow-
der, or from metal free from cavities.
The densities of the castings are, hence, much lower than
that of alloys given by other authorities, and for this reason
the density of No. 6 A (87.15 copper, 12.69 tin) in the shape
of fine turnings gave the figure 8.943, and turnings of ingot-
copper gave the figure 8.874.
The strength and density are in a certain degree depend-
ent upon each other, and the greater the density of an alloy
of any given composition the greater the strength. This has
been shown in experiments on gun-metal, which uniformly
exhibits an increase of strength with increase of density.
The casting of small bars, such as have been used in the
experiments described, is especially unfavorable to the pro-
duction of metal of great density, while in the casting of guns
and other large masses the pressure of molten metal is much
greater, and all conditions favor the increase of density and
of strength.
It is probable that the actual specific gravities of all alloys
containing less than 25 per cent, tin do not greatly vary from
356 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
8.95, and that the specific gravities of castings of these alloys
will be less than 8.95 as they exhibit porosity. The specific
gravity of an alloy is increased by repeated working.
In determining the specific gravities, the pieces were first
washed in alcohol to free them from any dirt or grease which
might be attached to them, and then thoroughly dried.
Before weighing in water, the pieces were boiled for two or
three hours, to remove, as far as possible, the air inclosed in
the pores of the metal, and after cooling in the dish in which
they were boiled, they were placed under the receiver of an
air-pump, and the air was further exhausted. They were
then quickly transferred to distilled water, in which they were
weighed, suspended by a loop of fine platinum wire from
the arm of the balance. The water in which they were
weighed was kept at the same level, and the proper correc-
tion made for weight of the platinum wire.
The results given are corrected for temperature of the
water, being reduced to the standard of water of maximum
density (39°.4 Fahr., 4°.! cent.).
If the formation of the gas which causes blow-holes can
be prevented, or if it can be removed from the metal while
the latter is still in a fluid state, it is evident that the cast
metal will be entirely free from them, and a metal of great
density and strength will be obtained.
No means has yet been discovered by which this desirable
result may completely be accomplished, but it is not improb-
able that it may be done by treatment of the fluid metal, or
by the use of fluxes. The subject offers a fruitful field for
experiment, one which it was proposed to explore, after con-
cluding the researches on copper-tin, copper-zinc, and triple
alloys, but one which was not carried out by the U. S. Board.
The specific gravity of an alloy is increased by repeated
tempering and rolling.
The specific gravity of pure copper, according to authori-
ties quoted in "Constants of Nature" varies from 8.360 to
8.958, electrolytic, hammered, rolled, or pressed copper giv-
ing the highest figures and those which are probably the most
nearly correct.
STRENGTH OF BRONZES.
357
35 8 MATERIALS OF ENGINEERING—NON-FERROUS METALS.
The specific gravity of all alloys containing between 25 and
38 per cent, tin, which alloys are compact and homogeneous,
is greater than 8.9 (reaching 8.97 at the latter percentage).
The specific gravities given in the tables, as determined
from the castings, show the cause of imperfections in strength
and other qualities, and indicate that one proper method of
improving strength is to increase density. They indicate that
the lower the specific gravity of alloys which show a certain
definite strength, the greater increase may probably be ex-
pected from any cause which brings the specific gravity up
to 8.95.
Rolling, hammering, or compressing porous and ductile
metals increases density. Casting under pressure has the
same effect. It is probable also that temperature of pouring
and rate of cooling have an influence upon density, and the
use of fluxes which may remove occluded gases from the
molten metals will increase it also.
The maximum density of the series is given by alloy No.
12 (62.31 copper, 37.35 tin, by analysis), the original mixture
of which corresponds to the formula SnCu3, and is nearly ap-
proached by alloy No. 38 (62.42 copper, 37.48 tin). The fig-
ures are 8.970 and 8.956 respectively. The former is higher
than is given by any authority known to the Author for any
alloy of copper and tin.
From alloy No. 12 to the end of the series, to pure tin, an
almost perfectly regular decrease of specific gravity occurs,
that of tin being 7.29. From the regularity of this decrease
of specific gravity it would seem that these alloys are but
little subject to porosity in castings. In these alloys the
density has no definite relation to strength.
213. Apparent Limit of Elasticity. — The apparent limit
of elasticity has been defined as the point at which distortion
begins to increase in a greater ratio than the force which
causes that distortion. In the curves of deflections and elonga-
tions, and in the autographic diagrams of torsional stress, it
is the point at which the curve begins (usually suddenly) to
change its direction and to deflect toward the horizontal.
The figure giving curves in which comparison is made of
STRENGTH OF BRONZES. 359
the transverse, torsional, and tensile resistance, also contains
curves showing the limit of elasticity under each of the three
kinds of tests. In the general summary of results (Table LXV.)
the elastic limits are represented by parts of the total re-
sistance.
It will be seen that the curves of limits of elasticity ob-
tained from the three kinds of tests, coincide with the curves
of resistance in the middle portion of the series, that contain-
ing the brittle alloys, and fall beneath them at the ends, the
figures in the summary showing the elastic limit to be there
100 per cent, of the total strength, and that of the more
ductile alloys to be in some cases as small as 20 per cent, of
the total strength, and to increase with the decrease of ductility.
In general, the ratio obtained by tensile test is higher
than that obtained by either transverse or torsional test.
In the stronger alloys, the elastic limit under tensile stress
is reached at from 50 to 68 per cent, of the breaking load, and
under transverse and torsional stress at 35 to 45 per cent. As
the percentage of tin is increased beyond 17.5 per cent., the
ratio of elastic limit to ultimate strength is increased ; alloy
No. 8 (76.64 copper, 23.24 tin) giving a ratio of 100 per cent. ;
the elastic limit was not reached till fracture took place. The
same result is given by all alloys from No. 8 to No. 21 (38.37
copper, 61.32 tin). From No. 21 to pure tin, this elastic limit
is reached before fracture, by both transverse and torsional
tests. In both tensile tests of alloys containing between 62.5
and 82.5 per cent, of tin the elastic limit was either not
reached or only just reached before fracture took place. In
these alloys, the ratios of elastic limit to ultimate strength
appear much higher in torsional than transverse stress. The
ductile alloys, containing large percentages of tin, give ratios
under torsional stress which gradually decrease as the per-
centage of tin increases, the decrease being nearly regular
from 98.5 per cent, to 45.3 per cent., between the alloy of
27.5 copper, 72.5 tin, and pure tin. In transverse test, the
ratio is much more nearly constant, varying somewhat
irregularly between the same compositions from 43.8 to 27.3
per cent.
360 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
^s
QSW
if
§§g§5S5SS
SlfiEA GTH OF BRONZES. 361
214. Moduli of Elasticity. — The moduli of elasticity were
calculated from deflections observed in transverse test. The
figures given are considered to be the most probable moduli
of each bar within the elastic limit where the deflections are
proportional to the applied loads. The figures and the curve
show irregularity, but not greater than should be expected
from metals of different compositions.
In alloys containing less than 24 per cent, of tin (all the
stronger and more valuable alloys) the modulus of elasticity
by transverse stress is about 14,000,000 (984,200 kilogs. per
sq. cm.).
From 25 per cent, to 35 per cent, tin, the modulus is some
what greater. From 35 to 75 per cent, there is a very great
irregularity, corresponding to the irregularity in strength and
other properties as shown by test, and much greater than any
other property.
From alloys containing 70 per cent, tin, to pure tin, the
moduli become a little more regular, the tendency being to
decrease as the tin increases. The modulus of these alloys
averages a little more than half that of the stronger alloys con-
taining less than 20 per cent, of tin.
215. Ductility is exhibited on the next set of curves.
Figure 14. The copper-tin alloys are ductile in all directions
when they contain principally tin or are nearly all copper,
As the proportions alter and become more nearly equal, the
ductility decreases, as the range between 25 and 75 per cent,
tin is approached from either side, and within that range are
very brittle. The alloys rich in copper are strong, though
ductile, while those rich in tin partake of the properties of
that metal. The method of variation of ductility is the same
for all methods of test, but the test by transverse loading of
bars gives greater opportunity for nice measurement and ex-
hibits better the gradual introduction of this element as the
lessening percentage of tin passes the figure 35 (copper, 65).
Alloys containing less than 20 per cent, tin or more than 85
per cent, gain in ductility rapidly as change of composition
goes on.
Ductility is thus variable, quite smoothly and regularly
MATERIALS OF ENGINEERING— NON-FERROUS METALS,
o-ci -_
8 8'
STRENGTH OF BRONZES. 363
with the composition of the alloy. In tension, ductility was
measured directly, except in the case of the most brittle alloys,
where it was too small to be measured. In transverse tests
it was easy to obtain its measure by noting the deflection,
which, in some cases, was greater than can be shown on the
scale ; some bars, in fact, could not be broken by bending
under the load. The autographic strain-diagram probably
gives the best means of comparison. The maximum angle of
torsion is 556.75 degrees, corresponding to an extension of
the most extended fibre, originally parallel to the axis, of 2.2,
nearly; the minimum, 0.4 degree, corresponds to an extension
of but 0.000.006 ; pure tin gives a value 200,000 times greater
than the most brittle alloy. Bars containing less than 12.5
per cent, tin did not break by bending to a deflection of 16
per cent, their length and 3^ times their depth. The illus-
trations given in the frontispiece exhibit the fracture of a
number of these alloys, and present to the eye the characteris-
tics of each, showing well the ductility or the brittleness, the
toughness or the crystalline or granular surfaces revealed by
breaking them.
216. Conductivity for heat and electricity varies in the
copper-tin alloys as seen in Figure 15, which represents the
data furnished by Calvert and Johnson, and by Matthiessen.
There is seen to be a general correspondence, with a sudden
break at the composition, copper 60 to 70, which appears in
the curve for heat-conductivity, but not in that for electric
conductivity. In both cases, this property remains practically
constant for all alloys between copper o and copper 60, and
rapidly improves as the alloy becomes more nearly pure cop-
per. The standard taken for comparison is pure silver. The
curves well illustrate the importance of securing purity in
copper intended to be used as a conductor.
217. The other Physical Properties of the copper-tin
alloys, as determined by various authorities, are exhibited in
Figure 16. Mallet gives data relating to ductility, mallea-
bility, hardness, and fusibility, on which are based several of
these curves. With this curve of hardness is compared that
of Calvert and Johnson, which corresponds, roughly, with it
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
i
I
\ fci.
II
sas&
m
rnrng
STRENGTH OF BRONZES. 365
so far as it goes. Hardness is here seen to increase steadily
from pure copper to copper 75, at which point that of mini-
mum ductility is reached. From this point it decreases stead,
ily and with tolerable uniformity to the opposite end of the
series.
Malleability takes an almost precisely opposite course,
falling to zero at copper 60-65 and rising again to the end
(pure tin).
Fusibility constantly lessens, as tin is added to copper,
from end to end of the whole range.
The curve of ductility closely follows that of malleability
in alloys rich in copper, but the lack of cohesion of tin causes
a great falling off at the opposite end of the line.
CHAPTER X.
STRENGTH OF BRASSES AND OTHER COPPER-ZINC ALLOYS.
218. The Brasses include all the copper-zinc alloys con-
taining one-half copper and upwards, and a few special alloys
are also given the name, as are copper-tin-zinc alloys, of which
the tin forms but a small proportion. The name bronze has
been applied, occasionally, to these ternary alloys, also. The
terms bronze and brass are used indifferently by the older
writers, but the tendency to restrict each term to a binary
alloy, or to a ternary alloy in which one constituent exists in
very small proportion, is decidedly observable among later
writers and they will be so used in this treatise.
In the cases of the brasses, as in that of the bronzes, no
systematic investigation of the properties useful to the engi-
neer had been made except by the U. S. Government. The
U. S. Board, to which allusion has been already frequently
made, authorized a determination of " the mechanical proper-
ties and of the physical and chemical relations of alloys of
copper, tin, and zinc," under the arrangement of committees
approved by the Board, which assigned to the Committee on
Alloys the duty of " assuming charge of a series of experi-
ments on the characteristics of alloys and an investigation of
the laws of combination."
This research was conducted in the Mechanical Labora-
tory of the Department of Engineering of the Stevens Insti-
tute of Technology under the direction of the Author. The
facts and data thus discovered and placed on record * will be
summarized in this chapter after reference to earlier work
on nearly related alloys.
* Report of U. S. Board, Vol. II. ; Ex. Doc. 23 ; 46th Congress, 2nd Ses-
sion. Washington : Government Printing Office, 1881.
STRENGTH OF BRASSES.
219. Earlier Experiments. — Mallet * found the tenacity of
an alloy of copper, 90.7, zinc, 9.3, to be 27,000 pounds to the
square inch (1,456 kilogs. per scj. cm.), with a specific gravity
of 8.6 ; with 3 per cent, more zinc the strength was increased
to very nearly 30,000 pounds (2,109 kilogs.). Copper, 85.4,
zinc, 14.6, had a tenacity of about 32,000 pounds (2,249.6 kilogs.),
and with copper, 83, zinc, 17, the figure became 31,000 (2,179
kilogs.). The tenacities varied little throughout the range
and down to copper, 2, zinc, I, which is a Muntz metal. Equal
parts copper and zinc exhibited a tenacity of 20,000 pounds
per square inch (1,406 kilogs. per sq. cm.) in Mallet's experi-
ments ; the Author has obtained, in some cases, 40,000 (2,812
kilogs.). Alloys rapidly become weaker, passing this maxi-
mum, as the proportion of zinc is increased, as will be seen
later, passing, however, a second maximum at about copper,
10, zinc, 90, which gives figures one-third as great as the first
maximum.
Brass cartridge metal tested with copper and steel by Lt.
Metcalfe at the Bridesburg Arsenal in samples trimmed out
to a contracted section of one inch (2.54 cm.), minimum
breadth, and 0.03 inch (0.076 cm.) thick gave results as fol-
lows:
TABLE LXVI.
TENACITY AND ELONGATION OF CARTRIDGE METAL.
LOAD.
PURE
COPPER.
COMMERCIAL COPPER.
BRASS.
OPEN HEARTH
STEEL.
Lbs.
Kilogs.
Unannealed.
Annealed.
I.
II.
500
600
800
1,000
,100
,200
,300
,400
,500
,600
,700
1,800
227
272
363
454
499
544
59°
635
680
7t6
771
817
0.024
0.040
0.078
0-155
0.005
0.020
0.063
0.156
0.266
0.005
0.015
0.040
0.087
0.130
0.214
0.290
0.033
0.050
0.075
O. 1O2
0.152
0.266
00.27
0.057
0.085
O.IIO
0.163
0.270
0.013
0.025
0.042
0.062
0.085
0.117
0.157
0.217
0.322
0.050
0.075
O. IOO
0.130
0.165
0.220
0.350
O.O225
0.030
0.0425
O.o6o
0.0775
0.140
0.230
0.005
0.0075
0.013
0.030
0.065
0.126
* Phil. Mag., Vol. 21, 1842.
368 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
As the test-pieces were of the " grooved " form the elonga-
tions serve for comparison of these specimens, but have no
absolute value.
220. Sterro-Metal, a brass which contains a little tin and
iron, was tested by Baron de Rosthorn at Vienna, and gave
the following results : *
TABLE LXVII.
TENACITY OF STERRO-METAL.
MATERIAL.
TENACITY.
Lbs. per sq. in.
Kilogs. per sq. cm.
Sterro-metal ;
t < «
« (i
Gun-bronze ;
cast
60,480
76,160
85,120
40,320
4.252
5,354
5,984
2,834
cold-drawn
cast
This alloy contained copper, 55.04; zinc, 42.36 ; tin, 0.83 ;
iron, 1.77.
The proportion of zinc may vary from 38 to 42 per cent,
without appreciably altering the value of the alloy. The
specific gravity of this metal was 8.37 to 8.40 when forged or
wire drawn ; it has great elasticity, stretching 0.0017 without
set, and costs 30 to 40 per cent, less than gun-bronze. It has
been forged into guns, cold from the casting. The strength
of sterro-metal containing one per cent, and more of tin will
be given in the following chapter on ternary alloys of copper,
tin and zinc.
221. The Moduli of Elasticity, E., of various alloys have
been found, as below, to the nearest round numbers :
* Holley ; " Ordnance and Armor," p. 424.
STRENGTH OF BRASSES.
TABLE LXVIII.
MODULI OF ELASTICITY OF BRASSES.
369
METAL.
VALUE OF E.
AUTHORITY.
REMARKS.
Lbs. on sq.
in.
Kilogs. on
sq. cm.
Brass. . . °
9.000,000
12,000,000
13,000,000
632,700
843,600
913,900
Tredgold.
Wertheim. )
Bauschinger. )
ii tin, 89 copper, cast.
Rolled.
<«
H
As will be seen, presently, the value is very variable with
ordinary cast alloys of copper and zinc, but should be toler-
ably uniform with rolled and drawn materials.
222. Copper-Zinc Alloys, including the brasses, were
studied by the Author, and the investigation was, as al-
ready stated, conducted in a similar manner to that described
in the discussion of the alloys of copper and tin.*
The specimens were in the form of bars, and were cast in
an iron mould square in section, and similar in dimensions to
that used in making bronzes. The experiments were made
upon these bars as cast under ordinary conditions as before.
The effects of different methods of casting, of slow and rapid
cooling, of compression, either of the fluid metal or after
solidification, and of rolling, tempering and annealing, were to
have been made the subject of a special research.
Two series of these alloys were made and tested. The
first series was composed of bars differing in composition by
5 per cent. The bars of the second series also differed in
composition by 5 per cent., the first bar containing 2^ per
cent, zinc, the last bar 'containing 97^2 per cent.
The bars were first tested by transverse stress ; the two
pieces remaining after each transverse test were turned to
size and tested by tension, and the four pieces thus formed
* This account is mainly abridged from the Report to the Committee on
Alloys of the U. S. Board.
24
37O MATERIALS OF ENGINEERJNG— NON-FERROUS METALS.
were tested by torsion. Some tests were made by compres-
sion. The turnings from the tension test-pieces were?
analyzed. The specific gravities were also determined.
The total weight of each casting was 4.5 kilograms (9.92
pounds).
223. Compositions Tested.— A following table (p. 371)
gives the compositions of the bars according to the original
mixtures, the compositions of two portions of each bar as
subsequently determined by analysis, and the specific gravi-
ties.
Bar No. 16 was made by melting together the upper half
of bar No. 17 (21.00 copper, 77.59 zinc) and the lower half of
bar No. 15 (25.98 copper, 72.90 zinc).
The mould was heated each time before pouring into it the
rnolten metal, the temperature given to it being higher the
larger the amount of copper in the alloy. In melting the
metal for bars, No. 7 to No. 21 (35 per cent, zinc to pure zinc),
inclusive, except No. 16, the copper was melted first and
covered with a layer of charcoal. The zinc was melted in a
separate crucible, and poured into the crucible containing the
molten copper, through the layer of charcoal. The mixture
was thoroughly stirred with a dry stick. Some volatilization
of the zinc took place, the amount being greater at some times
than at others ; but the causes of this variation were not
determined.
Bars No. I to No. 6 (5 to 30 per cent, zinc) were made by
first melting the copper, and then adding the zinc in the solid
state. The losses of zinc vary very irregularly, and in two
cases, bars Nos. 18 and 20(85 and 95 per cent, zinc), there ap-
peared to have been a greater loss of copper than of zinc.
The temperature of casting was then found by the
formula
in which P is the weight of the water, P the weight of metal
poured, / the temperature of the water before, and t' after
STRENGTH OF BRASSES.
37«
pouring, and c the specific heat of the alloy. The specific
heat was assumed to be the mean of the specific heats of the
components.
The following table gives the temperatures :
TABLE LXIX.
ALLOYS OF COPPER AND ZINC.
Estimation of Temperatures of Casting.
Composition
by original
mixture.
Weight
grammes.
Temperatures,
Fahrenheit,
Degrees.
Temperatures
of casting.
Degrees.
specific
Remarks.
1
tj
V
*
is
d
tuo
heat.
C
"^
I
5
g
1
%
3
"rt
C
§
ll
Q; >H
*
u
N
^
Jj
*
E
K
h
U w
I .
95
5
907
131.8
54
114
60
0.09517
4454
2456.7
Second casting.
2.
3-
4-
90
85
80
10
20
907
907
907
212.3
321.4
447-3
53
118
155
172
65
100
"4
0.09519
0.09521
0.09523
3035
3120
2600
1426.6
Poured thick.
5-
75
25
907
381.26
54
154
100
0.09525
2652
1455.5
6.
70
30
907
257-9
52
120
68
0.09527
2631
1443.8
7-
65
35
907
259-9
56
120
64
0.09529
2464
I351'2
8.
60
40
907
340.5
65
152
87
0.09531
2584
1417.7
9-
55
45
907
182.6
61
109
48
0.09535
2610
1432.1
ro.
50
So
907
199-5
54
104
50
0.09535
2492
T366.5
II.
45
55
907
237-4
53
102
49
0.09537
2065
1129.7
12.
40
60
907
223.3
61
112
0.09539
2284
1251.1
13.
14.
15.
35
30
25
65
7°
75
907
907
907
185.9
203.6
168.0
g
61
102
110
98
45
50
37
0.09541
0.09543
0.09545
2403
2444
2191
'317-3
1340.1
H99.5
Second casting;
Second casting.
16.
22.5
77-5
Not taken.
17.
20
80
907
169-3
51
.85
34
0.09547
1994
1089.6
Second casting.
18.
15
85
9-7
316.0
56
16
60
0.09549
19.
10
90
907
289.5
54
106
52
0.09551
1812
988.9
Second casting.
20.
5
95
907
163.0
60
:73-5
13-5
0.09553
860
460.0
21.
o
100
4535
597-3
5°
70
20
0-09555
1660
904.1
224. External Appearance of the Bars. — The surfaces of
bars No. I to No. 8 (5 to 40 per cent, zinc, original mixture)
had a similar color and appearance, being generally of a dark
yellow color, inclined to copper-red toward the copper end
of the series, and more or less oxidized. No. I (5 per cent,
zinc, original mixture) was variegated in color, exhibiting
iridescence in places, the prevailing tints being red, yellow,
brown, and green. No. 2 (10 per cent, zinc) was rough, blow;-
holes, ridges and depressions were found over the whole of the
bar. The others, from No. i to No. 7(5 to 35 per cent, zinc),
were smooth. No. 8 (40 per cent, zinc) was lough, the rough-
372 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
ness being caused by slight cavities or blow-holes of irregular
shape, none of which were deep. These bars were soft
enough to be cut with a saw, the freshly-cut surface varying
from yellowish-red at No. I to light yellow at No. 5 to No. 7
(25 to 35 per cent, zinc), No. 8 (40 per cent, zinc) being red-
dish-yellow. The hardness gradually increased with the in-
crease of zinc.
Nos. 9, 10, and II (45 to 55 per cent, zinc) had surface?
similar in color to the preceding, but darker, approaching
brown, and in some places covered by a light gray scale.
They were harder than Nos. I to 8, but could be cut in the
lathe with a good tool. It was noted that Nos. 5, 6, and 7
had a light yellow color, while the bars on each side, contain-
ing either less or more copper, were reddish-yellow.
Nos. 12, 13, and 14 (60 to 70 per cent, zinc) had a yellow-
ish outside surface, a Very thin skin; the metal itself when
broken was nearly white.
The yellowish skin contained more copper than the rest
of the casting ; it sometimes was so soft that it could be cut
or bent, while the inside of the bar was nearly as hard as
glass ; this was not determined by analysis. This soft yellow
coating found on white alloys of copper and zinc was described
by Mr. F. H. Storer.* The colors of the fractured surfaces
of Nos. 12, 13, and 14 were nearly white. They were too
hard to cut in the lathe. The ground surface of No. 12 was
brownish yellow. The ground surface of No. 13 had a yellow
tint, that of No. 14 was nearly silver-white.
This sudden change between No. II and No. 12 (from 55
to 60 per cent, of zinc) corresponds to that observed in the
copper-tin alloys of 24 to 30 per cent, of tin.
Between No. 14 and No. 15 another change occurs, the
yellow skin seen in No. 14 being entirely wanting in No. 15 ;
the color of the outside surface of the latter is a dull bluish-
gray. The fractured surface of No. 15 is bluish-gray, but
lighter than the outside. No. 15 is much softer than No. 14,
and can be cut in the lathe, although with difficulty.
* " Memoirs of the American Academy," vol. viii., 1860, p. 54.
STRENG TH OF BRA SSES. 3 73
From No. 15 to No. 20 (75 to 95 per cent, zinc) the sur-
faces are much alike, bluish-gray and nearly smooth, the
color becoming lighter as the proportion of zinc increases.
Hardness decreases with increase of zinc. No. 21, all zinc, is
softer than No. 20, and lighter in color. The fractured and
freshly cut surfaces of all bars from No. 15 to No. 21 are
bluish-gray. No. 20 and No. 21 only show a crystalline ap-
pearance, the others were finely granular.
We may divide the alloys of copper and zinc into three
classes, each of which has a distinct color. The first class
includes those containing less than 55 per cent, of zinc, and
may be called the yellow class. These are also the useful
metals. The second class includes those containing between
60 and 70 per cent, of zinc, which are nearly silver white and
exceedingly brilliant and hard and brittle. These have a
yellow skin. The third class includes all those having more
than 75 per cent, of zinc, and are bluish-gray, much softer as
well as stronger than the second class.
The alloys containing between 55 and 60 per cent, zinc
and those containing between 70 and 75 per cent, zinc, show
regular gradations between the first and second, and second
and third classes, respectively, the changes from one class to
the other taking place gradually, but within narrow limits.
225. Fractures; Colors. — The fractures of these alloys
were examined by Prof. A. R. Leeds, who furnished the fol-
lowing description of their color and structure :
No. o (cast copper). — Coarsely fibrous, and radiate from
centre of surface of fracture. Color, dark red from superficial
oxidation. Fibres, interrupted and dotted over with minute
ridges with sharp lines of separation.
No. I (96.07 copper, 3.79 zinc). — Surface, confusedly vesic-
ular and projecting between the vesicular cavities upward
into sharp points. Color of centre, brilliant yellow-red, chang-
ing to light red on sides of fracture. The latter portion was
likewise radiate in character, approaching No. o.
No. 2 (90.56 copper, 9.42 zinc). — Fracture, closely resemb-
ling No. i, with vesicular surfaces inferior in size. Color,
more nearly approaching yellow.
374 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
No. 3 (89.80 copper, 10.06 zinc). — Fracture, highly vesic-
ular and extremely jagged from the great number of minute
projecting points. Light yellow in centre, and feebly reddish-
yellow at sides of fracture. The latter portion was likewise
radiate in character.
No. 4 (81.91 copper, 17.99 zinc). — Surface in character re-
sembling No. 3, but less acutely jagged. Color, brass-yellow.
No. 5 (76.65 copper, 23.08 zinc). — Surface pitted over with
minute rounded depressions, and ridged up into regular ele-
vations, with a somewhat rough feeling to the touch. Color,
full yellow.
No. 6 (71.20 copper, 28.54 zinc). — Resembling No. 5, but
the elevations more prominent and more acute to the sense
of touch. Color, dark yellow.
No. 7 (66.27 copper, 33.50 zinc). — Centre of surface of
fracture largely vesicular, the surfaces of the vesicles being
likewise covered with minute rounded depressions. Color,
gold-yellow.
No. 8 (60.90 copper, 38.65 zinc). — Surface slightly rough
and uneven, with a few smooth, rounded cavities. Color,
somewhat orange-yellow, apparently having undergone a
slight superficial oxidation.
No. 9 (55.15 copper, 44.44 zinc). — Extremely rough and
uneven. Surface tarnished, of dull reddish-yellow color.
One large rounded cavity coated with smooth surface of gold-
yellow color.
No. 10(49.66 copper, 50.14 zinc). — Confusedly vesicular,
with regular surface of demarkation between the depressions.
Not homogeneous. Surface at centre, deep yellow, surrounded
by the larger portion of a whitish-yellow alternating with
reddish-yellow, and bounded at sides by a radiated border of
a similar color. Splendent.
No. ii (47.56 copper, 52.28 zinc). — In character somewhat
approaching No. 10, but the lines of demarkation between
depressions less evident, and the projecting ridges less promi-
nent. Color, reddish-white. Brilliant.
No. 12 (41.30 copper, 58.12 zinc). — Largely conchoidal
surface of fracture, with few surfaces and those smooth.
STRENGTH OF BRASSES. 375
Dull orange-yellow color. Splendent. (The color of this
fracture was nearly silver-white when freshly broken, but
changed to yellow by oxidation.)
No. 13 (36.62 copper, 62.78 zinc). — Character of surface
same as No. 12. Color more silvery. Splendent.
No. 14 (32.94 copper, 66.23 zinc). — Conchoidal fracture,
with surface covered with rounded depressions too minute to
be separately visible to the naked eye. Color, bluish-white.
Splendent.
No. 15 (25.77 copper, 73.45 zinc). — Minutely vesicular
fracture, giving a slightly rough surface. Color, dull bluish-
white.
No. 17 (20.81 copper, 77.63 zinc). — Similar in color and
surface to No. 15, but radiate fibrous in structure.
No. 1 8 (14.19 copper, 85.10 zinc). — Closely resembling No.
17. Color, dull bluish-white.
No. 19 (10.30 copper, 88.88 zinc). — Surface in small, un-
even ridges, dotted over with rounded depressions of brilliant
silvery surface. General color of mass, dull bluish-white.
No. 20(4.35 c°PPer>94-59 zinc). — Extremely jagged sur-
face. Large vesicular depressions, with splendent silvery
surface. Color of mass, bright bluish-white. Sides of fract-
ure, crystalline radiate.
No. 21 (cast zinc). — Large lamellar crystalline plates, with
rough surfaces of fracture between the laminae. Structure of
crystals also radiating from centre. Splendent. Bluish-
white.
The second series comprises twenty bars. They were
tested, mixed, and cast in the same manner as those of the
first series. The table (p. 378) gives the composition mixture
of each bar, the composition by analysis, and specific gravity.
226. Temperatures of Casting. — The following table
contains the temperatures of casting :
MATERIALS OF ENGINEERING—NON-FERROUS METALS.
TABLE LXX.
ALLOYS OF COPPER AND ZINC.
Temperatures of Casting.
COMPOSITION
BY ORIGINAL
MIXTURE.
WEIGHTS,
GRAMS.
TEMPERATURES,
FAHRENHEIT.
(DEGREES.)
1
E
TEMPERA-
TURES OF
CASTING.
(DEGREES.)
P
.
li
REMARKS.
1
jj
O
rt
1
1
1
c
Q
|
.c
I
c
CJ
N
&
'3
£
rt
K
<
h
3
97.5
92.5
87.5
2.5
7-5
12.5
Temperature not taken.
Temperature not taken*
907
907
167.26
64
112
48
0.09518
2847.2
^564.
«* O
82.5
9°7
277.17
64
140
76
0.09522
2752.3
'S11^
77.5
22.5
907
482.59
68
188
120
0.09524
2558.7
1403.7
72.5
27.5
907
426.95
60
158
98
0.09526
2343-9
1284.4
67-5
32.5
907
577.70
64
180
116
0.09528
2091.8
"44.3
62.5
37.5
907
439-55
63
168
105
0.09530
2441.9
1338.8
57.5
42.5
907
397-42
^8
158
100
0.09532
2552.7
1400.4
52.3
47-5
907
339-05
60
142
82
0.09534
244^.3
1339-5
47.5
42.5
37-5
37-5
52.5
57-5
62.5
67.5
907
907
907
907
296.53
388.15
327.33
224.45
08*
64
88
130
158
142
138
76
90
78
50
0.09536
0.09538
0.09540
0.09542
2568.2
2363-3
2407-9
2255.8
1409.
1295.1
I3I9-9
Mixed well; poured hot.
Considerable zinc vola-
tilized ; poured thick.
27.5
72-5
907
221.19
66
112
46
0.09544
2088.7
1142.6
22.5
'7-5
12.5
E:S
87.5
907
907
907
322.52
278.40
165.18
62
11
125
104
95
45
27
0.09546
0.09548
0.09550
1981-3
1639.7
1647.7
1082.9
893-1
897.6
7-5
92.5
907
197.87
55
92
37
0.09552
1867.9
1019.9
2.5
97-5
907
180.36
67
93
26
0.09554
1461.8
794-3
The cast-iron mould was heated before pouring bars Nos.
31 to 41 inclusive, but was cold for bars Nos. 21 to 30 inclu-
sive ; when the molten metal had a high enough temperature
given it, no difficulty was experienced by chilling.
As will be seen later, the zinc used in the second series,
although sold as of good commercial purity, contained one
per cent. lead.
227. Analyses. — The following table gives, at one view,
all the quantities thus far referred to :
STRENGTH OF BRASSES.
TABLE LXXI.
ALLOYS OF COPPER AND ZINC.
Analyses and Specific Gravities.
First Series.
ORIGINAL
MIXTURE.
ANALYSES.
VARIATION OF
COMPOSITION.
MEAN
ANALYSES.
-
0
•l
OS
.
.
.
.
u
§3 2
I
&
1
0
1
d
C
N
1
a
d
c
N
1
g
N
SPECIFl
9
I &::::
95
95
5
5
95.98
96.16
3-°o
3-68
+0.98
+ 1.16
— 1. 10
-1.32
•96.07
3.79
j 8.795
(8.854
[8.825
2 A
90
90
10
10
90.49
90.62
9-48
9-35
+ 0.49
+ 0.62
-0.52
—0.65
•90.56
9.42
J 8.758
18. 788
[8.773
3 A
11
15
15
89.31
90.29
10.54
7-57
+ 4-3^
+ 5.29
-4-69
-5-43
•89.80
10. 06
j 8.643
18.669
[8.656
4 A::::
4 B....
80
80
20
20
81.97
81.85
17-95
18.03
+ i 97
+ 1.85
-2.05
— 1.97
•81.91
17.99
J8.6o3
18.593
[8.598
5 A....
5 B....
6 A....
6 B....
75
75
70
25
25
30
30
77.84
75-45
71-34
71.06
21.78
24-37
28.55
28.52
+ 2.84
+ o 45
+ i 34
+ 1.00
-3.22
—0.63
— 1.45
-1.48
•76.65
[71.20
23.08
28.54
j 8.539
(8.517
j 8.458
1 8.429
[8.528
[8.444
7 A ...
8 A*.*/.'.
8 B....
60
60
35
35
40
40
67.24
65-29
62.68
59.19
32-49
34-5'
36.91
40.39
+ 2.24
+ 0.29
+ 2.68
— 0.81
-2.51
—0.49
-3.09
+ 0.39
•66.27
•60.94
33.50
38.65
j 8.392
j 8.350
j 8.443
18.367
•8.371
[8.405
9 A....
|B.::;
55
55
45
45
59- '3
51.16
4036
48.52
-3*84
-4.64
+ 3-52
•55-15
44-44
18.369
1 8.196
[8.283
10 A....
10 B
50
So
50
5°
52.21
47-"
47.48
52.79
+ 2.21
-2.89
— 2.52
+ 2.79
49.66
50.14
(8.301
18.28i
[8.291
ii A...
ii B....
12 A....
12 B....
45
45
40
40
55
£
60
47-45
47-67
42.09
40. 51
52.35
52.20
57.32
58.9'
+2.45
+ 2.67
+ 2.09
+ 0.51
-2.65
—2.80
-2.68
-1.09
[47.56
52.28
58.12
!8ic6i
8.061
8.061
13 A....
13 B....
35
35
65
65
36.52
36.72
63.20
62.36
+ T.52
-i. 80
-2.64
36.62
62.78
7.988
7-959
7.974
14 A....
14 B....
3°
30
70
70
34-71
67.84
64.62
+ I.I7
+ 4.71
— 2.16
-5.38
•32.94
66.23
I 7.847
1 7-775
7.811
15 A....
15 B....
16 A....
16 B....
25
25
22.5
22.5
75
75
77-5
77-5
25-56
25.98
26.44
25.40
74.00
72.90
72.73
73.38
+ 0.56
+ 0.98
+ 3-94
+ 2.90
- 1. 00
— 2.IO
-4-77
-4-12
[25.77
[25.92
73-45
73.06
j 7-627
1 7.722
J7-694
1 7-684
[7^75
[7-687
17 A....
35-
20
20
80
80
21.00
20. 6l
77-59
77.67
+ 1.00
+ 0.61
-2.41
-2-33
[20.81
77.63
I 7-5oo
1 7-336
[7.418
18 A
18 B....
15
IS
85
13.86
J4-51
86.03
84.16
— 1.14
—0.49
+ 1.03
— 0.84
•14.19
85.10
(7.166
1 7. '59
[7.163
19 A
19 B....
10
10
90
90
10.41
10.19
89.02
88.74
+ 0.41
+ 0.19
— 0.98
— 1.26
['0.30
88.88
7-iSi
1 7-325
[7.253
20 A....
20 B
5
5
95
95
tfj
94.69
94.48
—0.67
—0.64
-0.3I
-0.52
[ 4-35
94.59
j 7-177
1 7-038
7.108
21 A.
7.I4O
j
21 B....
o
100
/ . *^v
7.146
[7.143
37** MATERIALS OF ENGINEERING— NON-FERROUS METALS
TABLE LXXL— Continued.
Second Series.
ORIGINAL
MIXTURE.
ANALYSES.
VARIATION OF
COMPOSITION
MEAN ANALYSES.
j
y
E
o
W H
^ <!
B
LJ
jj
.j
|j
y
2 ta
5
§•
u
d
1
c
1
1
c
1
s
i
E
3°
U
N
°
N
3
U
N
U
N
3
1
22 A....
22 B....
97-5
97-5
2.5
2-5
97.98
97.68
i. 60
2.16
None.*
None.*
+ 0.48
+ 0.18
-0.90
— °-34
[97.83
1.88
0 1
8.786
8.796
[ 8.791
23 A....
23 B....
92.5
Q2 . 5
tt
92.65
91.99
7.42
7.94
Trace.
Trace.
+ 0.15
-0.50
— o.o£
+ 0.44
[92.32
7.68
Trace]
8^767
- 8.74<S
24 A....
24 B ...
87J
12.5
"•5
88.86
89.01
ii 06
10.88
0.12
0.16
+ 1.36
+ 1.51
-1.44
— 1.62
[88.94 10.97
0.14]
8.764
8.729
8-747
25 A....
25 B....
82.5
82.5
J7-5
'7.5
82.8-5
83.00
17.06
16.90
0.17
0.16
+ 0.35
+ 0.50
-0.44
-0.60
[82.93
16.98
0.17-j
8.662
8.603
8.633
26 A....
26 B....
'7-522.5
77-5,22.5
79-13
75.65
20.77
24.12
0.06
0.14
+ 1.63
-x.85
-i-73
+ 1.62
77-39
22.45
O.IO-j
8.607
8.542
[ 8.574
27 A....
27 B....
72.5
72.5
27-5
27-5
75-13
71.27
24.51
28.42
0.16
0.21
+ 2.63
-1.23
-2-99
+ 0.92
•73-20
26.47
J
.19-j
8.5"
8.418
[ 8.464
28 A...
28 B ....
67.5
67.5
32.5
32.5
70.65
68.82
29.16
30.95
o.ig
0.23
+ 2 i5
+ 1.32
-3-34
— ».5S
[69.74
30.06
O.2I •<
8.401
8.366
[ 8.384
29 A
29 B
62.5
62.5
37-5
37-5
63-36
63-52
36.46
36.26
O.IO
0.12
+ 0.86
+ 1.02
- 1.04
-1.24
[63.44
36.36
O.II-j
8.417
8.405
8.411
30 A....
30 B ...
57-5
57-5
42.5
42.5
58.22
58.75
41- 25
40.94
0.47
0-37
+ 0.72
1.25
-1.25
-1.56
[58.49
41.10
0.42J
8.367
8.358
8.363
31 A....
31 B....
52.5
52.5
47-5
47-5
55- °2
54-69
44-57
44-99
0.40
0-34
2.52
2.19
-2.93
-2.51
•54.86
44-78
°-37|
8.322
8.280
[ 8.301
32 A....
32 B....
47-5
47-5
52.5
52.5
49.05
48.85
50.71 0.32
50.93 0.26
i-55
'•35
-1-79
-i-57
48.95
50.82
0.29-!
8.228
8.203
[ 8.216
33 A....
33 B...
42-5
42-5
57-5
57-5
43-68
43-0*
55-«9: 0-4'
56.55! o-3*
1.18
o-54
-1.61
-0.95
43-36
56.22
o.38J
8-999
• 8.034
37-5
37-5
62.5
62.5
38.25
38.46
61.18 0.62
60.92 0.58
0.75
0.96
-1.32
-1.58
38.36
61.05
0.60]
7-987
7.976
7-982
35 B::::
32.5
32-5
67.5
67-5
35.83
35.52
63.55 0-66
63.87 0.66
3-33
3-02
-3-95
-3-63
35-68
63.71
0.66-j
7-973
7-959
7-966
36 A ....
36 B....
27-5
27-5
72.5
72.5
28.78
29.62
70-59
69.75
0-55
0-55
1.28
+ 2.12
-1.91
-2.75
29.20
70.17
0-55 j
7.785
7.746
[ 7.766
37 A....
37 ?••••
22.5
22.5
77-5
77-5
21.77
21.86
77.40
77-46
0.70
0.63
-0-73
— 0.64
— o. 10
-0.04
21.82
77-43
0.67 |
7-452
7-379
[ 7.4i6
38 A....
38 B....
'7-5
T7-5
82.5
82.5
-17.16
17.81
81.87
81.36
0-99
0.86
-0.34
+ 0.3I
— 0.63
-1.14
17.49
81.62
°-93 1
7.231
7.218
[ 7-225
39 A....
39 B....
12.587.5
11-75
12.48
87.19
86.14
0.99
1.22
-0-75
— O.O2
-0.31
ita,i2
86.67
,„]
7.258
7.217
f 7.238
40 A....
40 B....
7-5 92-5
7-592.5
7.19
7.21
92.34
91.79
0-54
1.02
-0.3I
-0.29
— 0.16
-0.71
[ 7-20
92.07
o.ySJ
7-293
6.968
7.I3I
t! B:::
2-597-5
2-5 97-5
J.;jj
96.20
96.65
!.o8
1.02
+ 0.15
-•0.24
96.43
1.05]
7.177
6.982
[ 7-080
1
1
228. Results of Tests. — The next table contains the data
obtained by test, arranged in order of composition, beginning
with copper and ending with zinc, and carefully classified.
The figures are, in each case, averages derived from two or
more tests each.
* No. 22 A had 0.37 per cent, iron and 22 B 0.24 per cent. iron. The
others had no iron or only traces.
3
COM
ION
STRENGTH OF BRASSES.
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380
MATERIALS Of ENGINEERING.— NON-FERROUS METALS.
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STRENGTH OF BRASSES. 38 1
229. Conclusions from Tests. — In the preceding table,
the " breaking load " by transverse stress is that which either
causes a deflection of 3^ inches (9 cm.), or breaks the bar
within that limit. The limit of elasticity is not a definitely
marked point in any cases in which brasses or bronzes are
under test, and the quantity here given as a limit is to be
taken as approximate only, and not as representing a fixed
natural quantity. The moduli of elasticity were calculated
from a series of deflections and loads, and the highest of the
series of values so obtained is usually recorded as probably
most correct, errors of observation and accidental errors usu«
ally operating to depress the value.
Alleys containing less than 10 per cent, zinc were usually
somewhat defective and spongy. Fluxing may be expected
to give sound casting only when special care is taken, as cop-
per has a great affinity for oxygen and absorbs air freely when
the metal is fluid.
Alloys containing less than 55 per cent, zinc are yellow,
and have been classed as " useful alloys." Those containing
less than 40 per cent, are noticeably weaker than those con-
taining from 40 to 55. The former are ductile and have
either a fibrous or an earthy fracture ; the latter are, in some
cases, of nearly or quite double their strength, with less duc-
tility, and the fractures are granular and lustrous. The maxi-
mum strength is found not far from the composition, copper,
60 ; zinc, 40. The white alloys (zinc, 40 to 50 ; copper, 60 to
50) are weak, brittle, vitreous, and useless for ordinary pur-
poses of construction. The blue-gray alloys (zinc, 70 to 100)
are granular or crystalline, stronger than the white, but weaker
than the yellow alloys, and have considerable ductility. The
range of valuable composition, which, in the copper-tin alloys
or bronzes, extends over a variation of but 25 per cent., covers
a range of 50 per cent, in the list of brasses. In both classes,
a sudden and great variation of properties is observed at a
certain point, and the maximum and minimum are not far
apart in either the brasses or the bronzes.
Alloy No. 4 (copper, 82 ; zinc, 18), a good casting, was so
ductile that it could not be broken by bending, but was sawn
382 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
apart after test. Some interesting experiments, exhibiting
the effect of prolonged stress on the brasses, were made, which
will be described fully later. Maximum tenacity was exhib-
ited by alloys containing about 40 per cent, zinc (copper, 50),
and attained nearly 55,000 pounds per square inch (nearly
3,867 kilogs. per sq. cm.). The highest resistance to trans-
verse stress was exhibited by the alloy copper, 47.7, zinc, 52.3.
The softer alloys tested by tension usually stretch not only
from end to end of the reduced part of the test-piece, but
also in the heads by which they were held in the testing
machine. In the case of an alloy containing 39 per cent, zinc ;
61 copper, a peculiar irregularity of elongation during test
was observed, and a similar phenomenon was noted in the
deflection of the same alloy under transverse loads. Between
40 and 50 per cent, zinc, liquation was often observed to oc-
cur to a serious extent.
Tests conducted with the autographic recording machine
were concordant with those made by tension, and the quality of
the metal was exhibited fully by the strain-diagrams so ob-
tained. An alloy containing 89.8 per cent, copper exhibited
great strength combined with a ductility about equal to that
of pure tin. An exterior fibre, originally parallel to the axis,
was extended to 3^ times its original length. Alloys ap-
proximating 90 per cent, copper had very great total resili-
ence. Alloys containing copper, 40, zinc, 60, were extremely
rigid, extending, in some cases, less than o.oi of one per cent.,
and even as little as 0.00006 of their original length. Alloys
containing copper, 15, zinc, 85, were subject to serious loss of
strength in consequence of the existence of minute pores in
large numbers, which, while invisible oftentimes, may injure
the casting more seriously than large blow-holes usually weaken
alloys liable to them.
When testing by compression, a reduction of 10 per cent,
in the length of the ductile alloys was made the limit, but the
loads causing a compression of 5 and of 20 per cent, and up-
ward, were also reported, as below. One of the silver-white
alloys was found to be the strongest, carrying a load exceed-
ing 120,000 pounds per squWe inch (over 8,436 kilogs. on the
sq. cm.).
STRENGTH OF BRASSES. 383
230. Notes taken during Tests are given at some length
in the report on this investigation. A few of the compo-
sitions exhibit properties, as thus recorded, which may be
given place here. In tension tests, in the first series, maximum
average strength is given by bar No. 9 (55.15 copper, 44.44
zinc), 44,280 pounds per square inch (3,113 kilogs. per sq.
cm.). An inspection of the table shows that this average re-
sult is reduced by liquation in bars No. 8 and No. 9, as No.
8 B (59.19 copper, 40.39 zinc) and No. 9 A (59.13 copper,
40.36 zinc) have nearly the same composition by analysis ;
and the strength of these pieces is much higher than the
average of the two pieces of either No. 8 or No. 9, being
51,380 and 53,660 pounds per square inch (3,612 and 3,772
kilogs. per sq. cm.), respectively. This indicates that maxi-
mum strength is possessed by an alloy containing less than
44 per cent. zinc. Transverse tests showed the maximum
transverse resistance to be exhibited by bar No. II (47.56
copper, 52.28 zinc), but this is not confirmed by tests made
subsequently by either tensile, transverse, or torsional stress.
Bar No. 12 (41.30 copper, 58.12 zinc) confirmed the results
obtained by the transverse test, showing an entirely different
metal from the preceding. It was weak and brittle. The
metal was so hard that the pieces could not be turned in the
lathe, and were therefore tested in their original square sec-
tions. No. 12 A broke at 4,324 and No. 12 B at 3, 130 pounds
per square inch (3,040 and 2,200 kilogs. per sq. cm.). No at-
tempt was made to measure the elongations; they were ex-
tremely small. The fractures were precisely like that ob-
tained by transverse stress.
The minimum tenacity, 1,774 pounds per square inch (1,247
kilogs. per sq. cm.), was exhibited by bar No. 14 A (31.17
copper, 67.84 zinc), one piece only being tested. The aver-
age tensile strength of No. 13 (36.62 copper, 62.78 zinc), which
showed the lowest transverse strength, was but little higher,
being 2,656 pounds (1,867 kilogs. per sq. cm.)
The curves of strength of the first and second series show
a generally close agreement, except in the highest part of two
curves, which are not found to indicate the same composition
384 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
of the bar of maximum strength. The curve of the second
series probably is most nearly the true one.
In the series of No. 29 (63.44 copper, 36.36 zinc), No. 29
A broke at 48,760, and No. 29 B at 46,840 pounds per square
inch (3,437 and 3,293 kilogs. per sq. cm.), after elongations of
31 and 32.4 per cent., respectively. The fractures were of
a light brownish-yellow color, and very compact and homo-
geneous. The plane of fracture was inclined to the axis, as
with most of the pieces, and the surfaces were slightly pol-
ished. The pieces were uniformly ductile throughout their
whole lengths, as was shown by the unifcrm decrease of di-
ameter as the pieces elongated. In testing No. 29 A, a sudden
dull sound was several times emitted from the piece, and at
the same instant the resistance decreased, in one case, 1,300
pounds (600 kilogs., nearly). This may be due to interior
molecular action, of the same nature as that which produced
the crackling sound noted in some transverse tests, or the
irregularity in the increase of deflections noted in others.
No. 30 (58.49 copper, 41.10 zinc). — The average strength
of the two pieces of this bar was higher than that of the pre-
ceding, and the highest of this series. No. 30 A broke at
52,260 and No. 30 B at 48,640 pounds per square inch (3,674
and 3,419 kilogs. per sq. cm.), after elongations of 10.18 and
10 per cent., respectively, showing much less ductility than
the preceding bars, with greater strength. There was observ-
able irregularity in the increase of elongations under increase
of load, which corresponds with the irregularity of deflection
observed in the transverse test of the same bar.
Heat was generated, in some cases of test by tension, suf-
ficient to make it uncomfortable to hold the broken end of
the test-piece in the hand. This was observed to be most
noticeable in alloys containing rather less than 75 per cent,
copper. While testing an alloy containing 63 per cent, cop-
per, sudden depressions of resistance were occasionally ob-
served accompanied by dull sounds probably due to internal
molecular disruption.
231. The Tenacity of Brass may be roughly reckoned,
when the proportion of copper exceeds one-half, as will be
S TRENG TH OF BRA SSES.
seen on comparing the data obtained from good specimens
of brass, as
T = 30,000 + 500 z.
232. In Compression Tests, it proved that No. 5 (76.65
copper, 23.08 zinc) was much stronger than either of those
richer in copper, requiring 42,000 pounds per square inch
(2,953 kilogs. per sq. cm.) to cause a compression of 10 per
cent. The elastic limit was apparently passed at about 26,000
pounds per square inch (1,448 kilogs. per sq. cm.). From this
point the curve, after turning toward the horizontal, proceeds
in a nearly straight line, but slightly convex to the axis of ab-
scissas till a compression of 35 per cent, is reached, showing
an increase of the ratio of load to compression, and indicating
that the increase of diameter which is given by the compres-
sion merely tends to increase the strength of the piece op-
posing a greater sectional area to the stress. The piece, after
35 per cent, compression, was bent in the form of a double
curve. On continuing the compression, the bending of the
piece caused it to offer a slightly diminished resistance, a di-
agonal crack appearing on one side, and the curve again shows
a curvature concave to the axis of abscissas.
On continuing the compression, after 140,000 pounds per
square inch (9,842 kilogs. per sq. cm.) of original section had
been applied, the compression amounting to 5 2.9 per cent.,
the resistance decreased to 110,000 pounds (7,733 kilogs.),
probably in consequence of the weakening produced by the
presence of the crack. The piece was then removed, the total
compression being 57.5 per cent. The piece after removal
measured only 0.87 inch in length, and two diameters at the
middle of the specimen measured 1.03 inches and 0.91 inch,
the section being approximately elliptical.
The turned surface was slightly roughened by the com-
pression.
No. 8 (60.94 copper, 38.65 zinc) proved to be much stronger
than No. 5, the load required to produce a compression of 10
per cent, being 75,000 pounds per square inch (4,956 kilogs.
25
386 MATERIALS OF ENGINEERING-NON-FERROUS METALS.
per sq. cm.). The elastic limit was apparently reached at
30,000 pounds per square inch (2,109 kilogs. per sq. cm.), after
a compression of 1.25 per cent. After passing the elastic
limit, the resistance again became nearly proportional to the
load, the ratio being much less than before. The piece be-
came slightly bent and the surface somewhat roughened by
the strain. After a compression of 24.8 per cent., the maxi-
mum resistance to this compression being 99,000 pounds per
square inch (7,000 kilogs. per sq. cm.), the resistance decreased
in consequence of the bending of the specimen. When the
piece was removed after a compression of 26.95 per cent, its
diameter was found to have increased to about 0.73 inch.
No. 9 (55.15 copper, 44.44 zinc) was somewhat stronger
than No. 8, a compression of 10 per cent, being caused by
78,000 pounds per square inch, and breaking at 136,000(5,883
and 9,561 kilogs. per sq. cm.), after a compression of 22.6 per
cent. The elastic limit apparently was reached at about
30,000 pounds per square inch (2,109 kilogs. per sq. cm.). At
136,898 pounds (9,625 kilogs.), after a compression of about
23 per cent., the piece suddenly gave way, a small piece
shearing diagonally from the upper end. The piece had be-
come slightly bent under the stress before rupture occurred,
and this bending may partly account for the breaking, as, in
consequence of the bending, the stress was brought upon one
side of the upper surface and was not distributed evenly over
the whole surface. The diameter of the piece was increased
to about 0.71 inch.
No. 10 (49.66 copper, 50.14 zinc) had a much greater re-
sistance to a given deflection than No. 9, a compression of 10
per cent, being caused by 117,400 pounds per square inch
(8,253 kilogs. per sq. cm.), and fracture occurring in precisely
the same manner as that of No. 9 at 123,860 pounds (8,707
kilogs. per sq. cm.), after a compression of 11.25 Per cent.
The elastic limit appears to have been reached at about 40,000
pounds (2,812 kilogs.), but the point is not clearly defined.
The diameter was increased to about 0.71 inch before break-
ing, being nearly uniform throughout the length. The surface
was very slightly wrinkled by the compression.
S TRENG TH OF BRA SSES. 3 8?
No. II (47.56 copper, 52.28 zinc) was much stronger than
any other of the series tested, breaking at 138,528 pounds per
square inch after a compression of 13.6 per cent., a compres-
sion of 10 per cent, being produced by 121,000 pounds (9,740
and 8,506 kilogs. per sq. cm.). The elastic limit was reached
at about 35,000 pounds (2,460 kilogs.). The behavior of this
piece before fracture was almost exactly like that of No. 10,
as is shown by the close agreement of their curves. The
fracture took place by shearing diagonally across the speci-
men just above the middle. The diameter was increased by
the compression to about 0.67 inch.
No. 15 (25.56 copper, 74.00 zinc) exhibited a behavior
under compression very different from that of the piece pre-
viously tested. It broke at 110,822 pounds per square inch
(7,791 kilogs. per sq. cm.), after a compression of 5.85 per cent.
An elastic limit was apparently reached at about 80,000 pounds
per square inch (5,624 kilogs. per sq. cm.), the ratio of com-
pression to load after this point being very much greater than
it was before this load was reached, as is plainly shown by
the curve. After 110,822 pounds (7,791 kilogs.) had been
reached, the compression being 4.8 per cent., the resistance
decreased to 107,562 pounds (7,563 kilogs. per. sq. cm.), as
the compression increased to 5. 85 per cent., and the piece then
suddenly broke, the upper half flying into several fragments,
a wedge-shaped piece being apparently formed at the top
which seemed to split open the lower portion. The diameter
was increased to 0.635 inch by the compression, as measured
after breaking, on the lower part of the specimen.
233. In Transverse Tests, which were the first in order,
an examination of the cast bars of the first series showed bars
Nos. i, 2, and 3 (3.79 to 10.09 zinc) to be defective, and the
results are not considered conclusive as to the properties of
the metal. These bars were soft and spongy, and, in places,
showed signs of oxidation. It appears probable that the de-
fective structure of these bars is due to the method of cast-
ing, which was not suitable for these compositions, and is
probably not necessarily an inherent defect of metals of these
compositions properly cast. In the second series the same
388 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
peculiarity was observed in the transverse tests of alloys con.
taining small proportions of zinc (less than 12.5 per cent.) with
one exception, a bar containing 7.5 per cent. This indicates
that it may be quite possible to secure good castings of alloys
containing small percentages of zinc, provided the proper
conditions are discovered and observed.
The causes of the formation of blow-holes and of oxida-
tion have not been determined. It would seem that the
strength of sound castings of these metals should approach
that of those having higher percentages of zinc. The curve
is, therefore, continued in a straight line from pure copper to
No. 4 (81.99 copper, 17.99 zinc).
All alloys of copper and zinc containing less than 55 per
cent, of zinc, may be considered as included in the first class,
or useful alloys, which are all distinguished by a yellow
color.
The forms of the curves of strength indicate that the first
class of alloys might be divided into two divisions, one show-
ing considerably greater strength than the other. The first
division includes those from No. 4 to No. 7 (17.99 to 33.50
zinc) inclusive, with also, probably, Nos. I, 2, and 3, or all
the alloys from pure copper to those containing 33.50 zinc.
These show a modulus of rupture from 21,000 to 28,000 (1,476
to 1,968 kilogs. per sq. cm.), increasing slightly with the per-
centage of zinc. They are also characterized by great duc-
tility and fibrous or earthy fracture. The second division in-
cludes bars No. 8 to No. II, inclusive (38.65 to 52.28 zinc),
which show much greater strength than the preceding, the
modulus of rupture of No. 8 being 38,968, and that of No. II
48,471 (2,740 and 3,407 kilogs. per sq. cm.), and less ductility.
The fractured surfaces of No. 8 and No. 9 (60.94 copper, 38.65
zinc, and 55.15 copper, 44.44 zinc) resemble in appearance
those of No. 7 (66.27 copper, 33.50 zinc), being earthy or
fibrous, but having a darker color. The fractures of No. 10
and No. II (49.66 copper, 50.14 zinc, and 47.56 copper, 52.28
zinc) are very different from those of bars containing less zinc,
having a granular structure and lustrous surface of fracture.
The modulus of rupture of No. 10 is much less than that of
STRENGTH OF BRASSES. 389
the other three bars of this portion of the series, Nos. 8, 9, and
H, but this is probably exceptional, as the fracture indicates
defective structure.
No II (47.56 copper, 52.28 zinc) gave the highest modulus
of rupture of the series, 48,471 pounds (3,407 kilogs.), and this
would indicate the maximum strength of the series ; but this
result is not confirmed by other tests of the same bar, nor by
any of the tests of the second series. These all indicate that
the point of maximum strength lies between No. 8 and No. 9
(38.65 and 44.44 zinc). The moduli of rupture of Nos. 8, 9
and 10, although much higher than those of the bars contain-
ing less zinc, are lower than those of nearly similar composi-
tion in the second series, but the reason of this is not ap-
parent.
Between bar No. II (47.56 copper, 52.28 zinc) and bar No.
12 (41.30 copper, 58.12 zinc) there is a sudden change of prop-
erties. Nos. 12, 13, and 14 (58.12 to 66.23 zinc) represent
the second class of the copper-zinc alloys, which, as noted in
describing the external appearance of the bars, is distinguished
by a nearly white color, vitreous fracture, and very brilliant
lustre, and also by great weakness and lack of ductility. They
correspond closely in all their properties to the silver-white
alloys of copper and tin. The minimum strength is given by
bar No. 13 (36.62 copper, 62.78 zinc), its modulus of rupture
being only about one-tenth of that of the maximum, bar No.
ii (47.56 copper, 52.28 zinc), which differs from it in compo-
sition only about 20 per cent.
Bar No. 15 (25.77 copper, 73.45 zinc) shows a very much
greater strength than No. 14, and marks the boundary of the
third class, which includes all the bars containing more than
73.43 per cent, of zinc. This class is distinguished by a blu-
ish-gray color, and finely granular structure, which becomes
crystalline as the composition approaches pure zinc, and a
much greater strength than the second class, although not so
great as the first class, the yellow and useful metals.
There is a somewhat irregular increase of strength from
No. 15 to No. 19 (73.45 to 88.88 zinc). The latter represents
the point of " second maximum " strength in the series, which
390 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
corresponds to the second maximum of the copper-tin alloys.
From bar No. 19 there is a regular and rapid decrease of
strength to pure zinc, which represents the " second minimum."
It will be noted that the curve of transverse strength of
the copper-zinc alloys is not nearly as regular as that of the
alloys of copper and tin ; but in many respects the two curves
show a marked resemblance. The most striking contrast be-
tween the two curves is the much greater range of composi-
tion of the useful metals among the copper-zinc alloys, the
curve of copper-tin alloys showing that the useful metals are
all comprised within the limits of less than 25 per cent, of
tin, while in the copper-zinc alloys the useful metals may
contain as much as 52 per cent, of zinc. A sudden decrease
of strength takes place at a definite point in both sets of al
loys, and the curves are in this respect similar. The bars of
minimum strength of both are also similar in their properties.
The point of minimum strength is very near the point of
maximum strength in both curves. That part of the curve
which represents the third class of alloys of copper and zinc,
corresponds with the curve of those copper-tin alloys which
contain more than 50 per cent, of tin, and, like it, shows a
second maximum ; but it shows that the alloys containing a
large amount of zinc have much greater strength than alloys
containing a large amount of tin. The former are also much
harder than the latter.
The transverse tests of the second series indicate the same
relations between strength, ductility, and composition that
were noted in tests of the first series.
From bars No. 22 to No. 28 (1.88 to 30.06 zinc), inclusive
(excepting bars No. 22 and No. 24 as defective), there is a
very gradual increase in the modulus of rupture. Bars No.
29 and No. 30 (36.36 and 41.10 zinc) show a rapid increase in
strength over the preceding; the corresponding moduli of
rupture are respectively 43,216 and 63,304 pounds (1,296 and
4,450 kilogs. per sq. cm.), the latter being the maximum
modulus of rupture of the series. This maximum does not
correspond with that of transverse tests of the first series, but
is confirmed by all the other tests.
STRENGTH OF BRASSES. 39!
234. Tests by Torsion confirm the results obtained and
deductions made from the other experiments :
From No. 4 to No. II (17.99 to 52.28 per cent, zinc) the
average strength of all the pieces is quite high, the curve con-
firming the curve of tensile results almost exactly, and indi-
cating the character of the first class, or useful alloys.
Between No. 11 and No. 12 (52.28 and 58.12 zinc) a very
sudden decrease of strength takes place, and Nos. 12, 13, and
14 (58.12 to 66. 23 zinc) show very low torsional strength, these
metals being in the second class, or silver-white and brittle
alloys.
From No. 15 (25.77 copper, 73.45 zinc) to the end of the
series (pure zinc) the torsional tests indicate the characteris-
tics of the third class, showing greater strength and ductility
than the second class, the latter quality increasing toward
pure zinc, and the strength reaching a maximum at No. 19
(10.30 copper, 85.10 zinc).
No. ii (47.56 copper, 52.28 zinc) gave a strain-diagram
similar in form to that of soft cast iron or hard bronze, and
very different from those obtained from alloys richer in cop-
per. Of No. 12 (41.30 copper, 58.12 zinc) two pieces only
were tested. The results correspond with those of tensile
and transverse tests, showing that the metal is extremely
weak and brittle. The fractures were silver-white, vitreous,
and conchoidal. The pieces were too hard and brittle to be
turned in the lathe, and were shaped by grinding with an
emery wheel. The ductility is extremely slight, the exten-
sion of a line of particles, one inch long in the surface parallel
to the axis, being only 0.00006 inch.
No. 13 C (36.52 copper, 63.20 zinc) was, if possible, even
weaker and more brittle than No. 12. Only one piece was
tested and this was not brought to a cylindrical form, but
was tested in its original square section. The strength was
much less than that of any other piece of the series, showing
the composition containing 63.20 zinc to be about that of
minimum strength. The strain-diagram was a straight and
nearly vertical line. Of No. 33 (43.36 copper, 56.22 zinc) two
pieces only were tested. They were too hard to be turned
3Q2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
in the lathe, and also were shaped by an emery wheel. The
torsional moments, after being reduced to the equivalents of
those of pieces of standard diameters, were much less than
those of the preceding bars. The appearance of the fractures
also showed as great a difference in the structure of the metal
as was indicated by the difference in strength. Both fract-
ures were diagonal, but No. 33 A was of a pinkish gray color
and finely granular structure, and No. 33 B was of a brilliant
silver-white color, smooth and vitreous. The analyses of the
turnings of the tension pieces show that the difference was
due to liquation ; No. 33 A containing 55.89 per cent, zinc,
and No. 33 B 56.55 per cent. zinc. The fact that so small a
difference in the percentage of zinc should make such a great
difference in properties is evidence of the very rapid though
continuous change which takes place on the boundary line
between the first and second classes of the copper-zinc alloys,
and which is plainly shown by the rapid fall of that portion
of the curve corresponding to alloys of about this composi-
tion.
235. Brass Shafts and spindles subjected to torsion may
be calculated by the formula
given in Chapter VIII., Art. 166, in which s varies from 5,000 to
60,000, according to composition and soundness of the alloy.
If A z is taken to measure the difference between the percen-
tage of zinc present and that of maximum resistance, 45 pel
cent., a rough estimate may be taken, as
s, = 50,000 — 333 A,?
when the alloy contains less zinc, and
s\ = 50,000 — 3,000 A z
between z = 45 per cent, and z = 60 per cent.
5 TRENG TH OF BRA SSES. 393
In metric measures,
s*m = 3*5*5 - 24 AS;
S\m = 3,515 ~ 21 I A*.
236. The Records of Tests of a selected number of cop-
per-zinc alloys are here given, and those of several others are
presented later when considering the effect of prolonged
stress on this class of materials. These records are extracted
from the set presented to the U. S. Board and printed in the
report of that body. Each record is accompanied by memo-
randa relating to the conditions of test and details of the ex-
periment which render further explanation unnecessary.
TABLE LXXIII.
TESTS BY TENSILE STRESS.
Alloys of Copper and Zinc. — Dimensions. — Length = 5" ; diameter =C, 798".
BAR NO. 25 B.
COMPOSITION. — Original mixture : Cu, 82.5 ; Zn, 17.5. Analysis : Cu, 83.00 ; Zn, 16.90.
M
«
2 o
M
1
.n
« o
b
<y
" .
* t*
D
O
™ .
ij
c/3
ii
9
0 M
P3
I5
SET.
i!S
Is
£5
o eS
y
SET.
!!S
O
j
w
J
i
i
Pounds.
Inch.
Inch
Pounds.
Inch.
Inch.
1,000
0.0014
0.03
17,000
0.3194
6.39
2,000
0.0037
0.07
18,000
0.3600
.
7.20
4,000
200
0.0104
0
0.21
19,000
20,000
0.4034
0.4460
8.07
8.92
6,000
0.0230
0.46
200
o 4404
7,000
0.0326
0.65
21,000
0.4892
9' 78
8,000
0.0412
,
0.82
22,000
°-5274
10.55
200
9,000
10,000
11,000
0.0616
0.0840
0
1. 00
1.23
1.68
23,000
24,000
32,800
Total el
0.5586 . .. 11.17
Measuring apparatus slipped.
Broke 2 inches from D end.
angation measured after breaking,
12,000
2OO
0.1154
I 00
2.31
1.17" = 23.4 percent.
Diameter of fractured section, 0.608".
13,000
0.1483
2.97
Tenacity per square inch original section,
14,000
15,000
O.I 880
0.2344
•
3-76
4.69
^2,800 pounds.
Tenacity per square inch fractured section,
16,000
0.2747
.
5-49
56,493 pounds.
2OO
o 2676
....
394 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXIIL— Continued.
BAR NO. 26 B.
COMPOSITION.— Original mixture : Cu, 72.5 ; Zn, 27.5. Analysis: Cu, 75.65 ; Zn, 24.15.
w
m
**•
M
m
z u.
\
5
« 0
3
z
% •
o 8
o g
£„
Ii2
*g •
£5
o2
SET.
§ G
S5
SET.
hS =
5 J
g
q
z
$
0
_]
H
M
i
3
M
j a. J
M
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
/-w->n
o 08
6 6c
O 12
2O,OOO
7 67
2OO
5,000
0.0144
0.29
O 43
21,000
22.OOO
o 4846
8.67
8,000
u.u^yy
0.74
24,OOO
0.5938
ii 88
200
0.0221
200
0.5788
9,000
o 0443
0.89
25,OOO
0.6480
12.96
10,000
11,000
12,030
200
0.0518
0.0646
0.0698
1.04
1.29
1.40
26,000
27,000
36,840
Total elc
0.7156
Measuring a
Broke 2 inch
>ngation mea
pparatus slip
es from B en
sured after
f**1
breaking,
0.0636
13,000
14,000
15,000
16,000
200
0.0878
0."33
0.1513
0.1867
I.76
2.27
3-03
3-73
1.27" - 25.4 per cent.
Diameter of fractured section, 0.587".
Tenacity per square inch, original section,
36,840 pounds.
Tenacity per square inch, fractured section,
0.1784
I7,OOO
0.2348
4.70
68,064 pounds.
18,000
0.2813
5.63
BAR NO. 29 B.
COMPOSITION.— Original mixture : Cu, 62.5 ; Zn, 37.5. Analysis : Cu, 63.52 ; Zn, 36.26.
1,000
O.OOII
0.02
25,000
0.2097
4.19
2,000
0.0034
0.07
26,000
0.2371
4-74
3,000
0.0055
......
O. II
27,000
0.2668
5-34
4,000
0.0078
0.16
28,000
0.2961
5-92
5,000
O.OIOO
......
O.2O
200
0.2784
6,000
O.OI2I
0.24
29,000
0.3287
6:57
7,000
0.0142
0.28
30,000
0.3665
7-33
8,000
0.0166
0-33
31,000
0.3988
7.98
9,000
0.0191
0.38
32,000
0.4260
8.52
10,000
0.0218
0-44
2OO
0.4252
11,000
0.0257
0.51
33.ooo
0.4790
9^8
12,000
0.0293
0-59
34,000
°-5I73
10.35
200
0.0075
35.000
o.5585
11.17
I3,OOO
0.0336
0.67
36,000
0.6090
12 18
14,000
0.0392
0.78
200
o!5886
15,000
0.0452
0.90
37,000
0.6*48
13.10
l6,OOO
200
17,000
0.0520
0.0643
0.0322
1.04
1.29
Measuring apparatus slipped.
47.840 | Broke i inch from B end.
Total elongation measured after breaking.
l8,000
19,000
0.0678
0.0812
1.62" — 32.4 per cent.
Diameter of fractured section, 0.656".
E0,000
200
0.1061
0.0814
2.12
The piece drew down very uniformly through
the whole length to a diameter of about
21,000
0.1142
2.28
0.685".
22,000
0.1350
2.70
Tenacity per square inch, original section,
23,000
24,000
0.1571
0.1836
3-'4
3-67
47,840 pounds.
Tenacity per square inch, fractured section,
200
0.1683
70,772 pounds.
STRENGTH OF BRASSES. 395
TABLE LXXIII. —Continued.
BAR NO. 4 A.
COMPOSITION.— Original mixture : Cu, 80 ; Zn, 20. Analysis : Cu, 81.97 \ Zn, 17.95.
LOAD PER SQUARE
INCH.
ELONGATION IN 5
INCHES.
SET.
ELONGATION IN
PER CENT. OF
LENGTH.
a
|i
ELONGATION IN 5
INCHES.
SET.
2§
1:1
§£3
M
26! 16
igs of the
loose, in
vn of the
ig elonga-
Lhe middle
breaking,
il section,
d section,
ameter of
nen were
Cend.
0^698
0.708
0.720
1,600'
2,000
4,200
5,000
6,000
7,000
8,000
120
9,000
10,000
11,000
12,000
120
13,000
14,000
l6,OOO
1 2O
l8,000
2O,OOO
Elongatio
Elongatio
100
22,000
24,000
26,000
Inch.
O.OOIO
0.0020
O.OO4O
0.0065
0.0077
0.0106
0.0139
0.0175
Inch.
0.02
0.04
0.08
0.15
0.21
0.28
0.35
0-45
0.58
0.85
1.25
1.79
2.67
4-45
8.92
[2.
5-
14.37
17.01
Pounds.
30,000
30,400
30,600
measur
conseq
square
Continue
tions, a
at 32, 2c
Total elc
Inches.
i . 3080
At this poin
ing instrume
uence of the
head of the si
d the test wit!
nd the piece
o pounds per
ngation as m
30.40 per cen
• of fractured
per square
>ounds.
per square i
>ounds.
wing measur
it portions o
fter breaking
red surface. . .
om fracture. .
>m fracture . .
Inch.
the fasteni
nts became
drawing doi
>ecimen.
lout measurii
broke near
square inch,
jasured after
.
section, 0.585
inch, origins
nch, fracture
ements 01 d
f the speci
A end.
0.585'
0.705
.. O.7I2
0.0099
0.0223
0.0290
0.0424
0.0626
0.0895
o.i337
0.2227
o.3253
. 0.4459 .
n increased in
n increased in
0.5809
0.7183
0.8504
Diametei
Tenacity
32,200 \
Tenacity
59.8,99 \
The folk
differei
made a
At fractu
% inch fi
T inch fn
2 inches
3 inches
0.0610
0.2204
2 m. to 0.45^
4 m. to 0.45;
0.4489
rom fracture 0.710
rrom fracture 0.710
BAR NO. 5 A.
COMPOSITION.— Original mixture: Cu, 75; Zn, 25. Analysis: Cu, 77.84; Zn, 21.78.
800
O.OOIO
0.02
22,000 0.5820
11.64
1,200
0.0020
0.04
24,000 0.7053
14.11
2,OOO
3,000
0.0043
0.0073
0.09
0.15
25,000 0.7655
26,000 Measuring apparatus slip
15-31
>ped : con-
4,000
0.0096
0.19
tinued test without measuring
5,000
0.0125
......
0.25
elongations.
6,000
7,000
0.0155
0.0206
0.31
0.41
34,040 Broke f inch from A end
Total elongation, measured after
breaking
8,000
0.0250
0.50
i. 80" = 36 per cent.
200
0.0143
Diameter of fractured section, 0.58^
9,000
IO,OOC
I J,OOO
0.0319
0.0380
0.0469
0.64
0.76
0.94
Tenacity per square inch, original section,
34,040 pounds.
Tenacity per square inch, fractured section,
12,000
200
0.0631
0.0600
1.26
63,322 pounds.
Diameters after breaking.
13,000
0.0933
1.87
Inch.
14 ooo
o. 1324
2.65
At fracture
o 585
16,000
0.2326
4.65
i inch from fracture
.... 0.672
2OO
0.2293
2 inches from fracture.
o 685
18,000
20,000
0.3440
0.4.601;
6.88
Q.2I
3 inches from fracture
o 6oj.
4 inches from fracture
' 0^6
Elongation increased in i m. to 0.4713".
c inches from fracture.
o 705
Elongation increased in 2 m. to 0.4795".
39t) MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE IXX1II.— Continued.
BAR NO. 8 B.
COMPOSITION. — Original mixture : Cu, 60; Zn, 40. Analysis: Cu, 59.19 ; Zn, 40.39.
•
L
10
s
5S
1
>n
§
*§
11
§§•
*ij
g|
tL
V, U
gfi
S3
SET.
rl
PS U
£2
P
SET.
n
§
s
S5
N
£ « a
|aa
I
I
S"
Pounds.
Inch.
Inch.
Potnub.
Inch.
Inch.
28,000
4.62
3,000
O.OO4O
0.08
200
0.2190
0.13
3O,OOO
0.2648
5.30
5,200
0.0075
0.15
32,400
0.3235
6.47
0.3062
0.23
34,OOO
0.3850
7.70
76,OOO
9.05
0.0008
2OO
0-4373
0.30
36,000
o 4860
0.72
10,000
11,000
12,000
200
0.0173
0.0191
0.0220
0.35
0.38
0.44
0.50
38,OOO
Measurin
50,520
51,380
Total elc
0.5700 11.40
g apparatus slipped.
(Elongat'n measured with calipers).
Broke in middle,
ne-ation. measured after breaking.
0.0075
14,000
0.0296
0.59
o 81
1.48" = 29.6" per cent.
Diameters of fractured section, 0.672" and
200
18,000
20,000
200
22,000
0.0545
0.0773
O.IIOO
0.0336
0.0716
i.'og
1.55
2.20
0.678" (elliptical).
Diameter of piece i inch from fracture, 0,687".
Tenacity per square inch original section,
51,380 pounds.
Tenacity per square inch fractured section,
24,000
0.1445
3.89
71,762 pounds.
200
•••••*
0.1341
26,000
0.1960
3-94
BAR NO. 9 A.
COMPOSITION.— Original mixture : Cu, 55 ; Zn, 45. Analysis : Cu, 59.13 ; Zn, 40.36.
2,000
O.OO24
0.05
200
0.1091
3,000
0.0038
0.08
28,000
0.1139
2 .'28
4,000
0.0056
O.II
30,000
0.1489
2.98
200
0.0016
32,000
0.1791
3.58
5,000
0.0072
......
0.14
200
0.1712
....
6,000
0.0086
0.17 1
36,000
0.3017
6.03
7,000
O.OIO2
0.20
40,000
0.4236
8-47
8,000
O.OII5
0.23
2OO
0.4077
200
9,000
10,000
11,000
O.OI3I
0.0137
0.01^2
0.0027
0.26 ;
0.27
0.30
44,000
48,000
53,660
Total elo
0.6201 12.40
Measuring apparatus slipped.
Broke at shoulder, B end.
ngation, measured after breaking.
12,000
2OO
0.0167
0.0082
0.33 j
1.27 = 25.40 per cent.
Diameter of fractured
section. 0.675".
13,000
14,000
0.0l82
O.O2OO
0.36
0.40
Diameter of piece i inch from fracture, 0.680".
Diameter of piece 3 inches from fracture,
15,000
16,000
O.O2I7
0.0240
0.43
0.48
0.680".
Diameter of piece 4
inches from
fracture.
2OO
O.O2OI
.... I
0.687".
17,000
0.0259
0.52
Diameter of piece 5
inches from
fracture,
18,000
19,000
0.0289
0.0323
0.58
0.65
0.704".
Diameter of piece 6
inches from
fracture,
20,000
22,000
0.0364
0.0460
0-73
0.92
0.710".
Tenacity per square
inch, original section,
24,000
26,OOO
0.0614
0.0832
5:8
53,660 pounds.
Tenacity per square inch, fractured section,
28,000
0.1136
1.27
74,975 pounds.
S TRENG TH OF BRA SSES. 397
TABLE LXXIV.
RECORD OF TESTS BY COMPRESSIVE STRESS.
AHoys of Copper and Zinc. Dimensions: Length = 2" (5.08 cm.);
diameter = 0.625" (J5 cm.).
BAR NO. 2.
COMPOSITION.— Original mixture : Cu, 90 ; Zn, 10. Analysis : Cu. 9.56 ; Zn, 90.42.
M
fc
*"
- o
<
« o
<y
2 h
g,
o H*
LOAD.
COMPRES-
SION.
a
|g*
LOAD.
COMPRES-
SION.
ft
£2
9
gag
5 Q, .
Q
IE!
°
8
S
8
Pounds.
Inch.
Pounds.
Pounds.
Inch.
Pounds.
500
0.002
1,630
O.IO
12,000
0.294
39,^4
14.70
1,000
0.004
3,250
0.20
I3,OOO
0-334
42,373
16.70
2,000
3,000
0.009
0.012
6,519
9,778
o.45
0.60
14,000
15,000
0.372
0.408
45,633
48,892
18.60
20.40
4,000
0.022
13,038
1. 10
16,000
0.442
52,152
22.10
5,ooo
6,000
7,000
0.046
0.083
O.Iig
16,297
*9,557
22,816
2.30
4-15
5-95
17,000
18,000
19,000
0.482
0.530
0.563
55,4"
58,671
61,910
24.IQ
26.50
28.15
8,000
9,000
0.152
0.187
26,076
29,335
7.60
9-35
20,000
Removec
0.599
I piece slighl
65,190
Jy bent, sui
29.95
•face very
10,000
0.225
32,595
11.25
rough.
11,000
0.262
35,855
13.10
BAR NO. 5.
COMPOSITION.— Original mixture : Cu, 75 ; Zn, 25. Analysis : Cu, 76.65 ; Zn, 23.08.
2,000
0.0085
6,519
o.43
22,000
0.476
71,709
23. «o
3,000
0.013
9,778
0.65
23,000
0.502
74,968
25.10
4,000
0.016
13,038
0.80
24,000
0.528
78,228
26.40
5,ooo
0.019
16,297
o.95
26,OOO
0.562
84,747
28.10
6,000
0.022
T9,557
1. 10
28,000
0.613
91,266
30.65
8,000
0.032
26,076
1. 60
30,000
0.652
97,785
32.60
9,000
0.042
29,335
2.10
32,000
0.691
104,303
34-45
10,000
0.065
32,595
3-25
34,000
0.734
110,822
36-70
11,000
0.109
35,855
5-45
36,000
0-773
II7,34I
38-65
12,000
0.154
39, "4
7.70
38,000
0.828
123,860
41.40
13,000
0.203
42,373
10.15
39,000
0.876
127,119
43-8o
14,000
0.243
45,633
12.15
40,000
0.916
130,379
45-8o
15,000
0.273
48,892
!3'65
41,000
.0.966
133,638
48.30
16,000
0.309
52,i52
iS-45
42,000
i. on
136,898
50.55
17,000
18,000
°-339
0.366
55,4"
58,671
16.95
18.30
43,000
Resistanc
1.058
:e decreased t
140,157
0 —
52.90
19,000
80,000
21,000
o.399
0.424
0.451
61,930
65,190
68,449
19-95
21.20
22-55
34,000 | 1.150 110,822 57.50
Removed piece squeezed out of shape with a
diagonal crack on one side.
398 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXIV.— Continued.
BAR NO. 9.
COMPOSITION.— Original mixture : Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44.44.
M
2 fc
i
2fe
i
* 0
•
- O
g,
2 H
g,
2 (4
LOAD.
COMPRES-
SION.
w X
K U
u y.
0, "
¥i
LOAD.
COMPRES-
SION.
•d
£ 5
m
Q
CU ^ ^
Q
o, Qi 2
S a! J
<
s S S
« 0, J
°
0
0
3
u
Pounds,
Inch,
Pounds,
Pounds.
Inch.
Pounds.
1,000
2,000
0.005
0.008
3,259
6,5J9
0.25
0.40
20,000
22,000
0.150
0.173
65,100
71,709
7-50
8.65
3,000
O.OIO
9,778
0.50
24,000
O.2O2
78,228
10.10
4,000
5,000
6,000
• 0.012
0.014
0.016
13,038
16,297
'9,557
o.oo
0.70 :
0.80
26,000
28,000
30,000
O.227
0.253
0.280
84,747
91,266
97,785
ii.35
12.65
14.00
7,000
0.019
22,816
0.95
32,000
0.299
04,303
14-95
8,000
0.023
26,076
1.15
34,ooo
0-335
10,822
16.75
9,000
10,000
0.026
0.032
29,335
32,595
1.30
i. 60
36,000
38,000
0.362
0.388
ass
18,10
19.40
11,000
0.040
35,855
2.00
39,000
0.405
27,119
20.25
12,000
0.050
39, "4
2.50
40,000
°-4T5
30,379
20.75
13,000
0.061
42,373
3-°5
41,000
0.436
33,638
21.80
14,000
15,000
l6,OOD
17,000
i 8, coo
19,000
0.075
0.087
O. IOO
0.113
0.125
0.138
Ji',892
55,4n
58,671
61,930
3-75
4-35
5.00
5.65
6.25
6.90
41,500 0.452
42,000
Broke suddenly, a sm
from upper corner.
Bent slightly.
135,268 22.60
136,898
all piece breaking off
BAR NO. II.
COMPOSITION.— Original mixture : Cu, 45 ; Zn, 55. Analysis: Cu, 47.56 ; Zn, 52.28.
1,000
0.002
3,259
O.IO
26,000
O.IO2
84,747
5.10
2,000
O.007
6,519
0-35
28,000
O.H5
91,266
5-75
3,000
O.OIO
9,778
0.50
30,000
0.130
97,785
6.50
4,000
5,ooo
O.OII
0.013
16,297
0-55
0.65
32,000
34,000
0.147
0.164
104,393
110,822
7-35
8.20
6,000
0.014
T9,557
0.70
36,000
0.188
"7,34I
9.40
7,000
0.016
72,816
0.80
37,000
0.198
120,600
9.90
8,000
0.018
26,076
0.90
38,000
O.2IO
123,860
10.50
9,000
0.019
29,335
o-95
39,00°
O.22I
127,119
II .05
10,000
0.021
32,595
1.05
40,000
0.239
130,379
"•95
12,000
0.028
39, "4
1.40
41.000
0.253
133,638
12.65
14,000
0.037
45,633
1.85
41,500
0.267
135,268
13-35
16,000
0.046
52,152 •
2.30
42,000
0.272
136,898
13.60
18,000
20,000
22,OOO
0.056
0.066
0.078
58,671
65,190
7i»709
2.80
3-30
3-90
42,500
just as
Fracture
> beam rose,
diagonally a
138,528
:ross the mic
Broke
die of the
24,000
0.090
78,228
4.50
specimen.
ST&ENG TH OF BRA SSES. 399
TABLE LXXV.
RECORD OF TESTS BY TRANSVERSE STRESS.
Afloys of copper and zinc. Dimensions : Length, / = 22" ; breadth, d»f
(2.54 cm.) ; depth, d = i" (2.54 cm.).
BAR NO. 4.
COMPOSITION. — Original mixture : Cu, 80; Zn, 20. Analysis: Cu, 81.91 ; Zn, 17.99.
§
\>
o
||
LOAD.
E
SBT.
ii
LOAD.
fc
SET.
E
Q <
h
o <
M
Q
Z w
i
0
s«
Pounds.
10
Inch.
0.0042
Inch.
Pounds.
Inches.
Inches.
20
0.0080
0.5885
40
80
0.0124
0.0206
9,030,560
10,708,667
480
0.7520
120
160
o . 0296
0.0363
11,349,217
12,339,278
520
1.1763
1.3463
1,189,949
200
i 6163
3
0.0056
560
1.86
240
580
280
0.0692
Beam sinks
11,327,350
600
2.62
641,107
320
360
400
3
0^3288
slowly.
0.2445
9,141,138
6,074,807
3,405,686
620 3.27
Bent down without
Breaking load, P =
Modulus of rupture,
breaking. Bar removed.
520 pounds.
-ff = 77-^ = 21, 193.
400
0.3352
BAR NO. 5.
COMPOSITION.— Original mixture : Cu, 75 ; Zn, 25. Analysis ; Cu, 76.65 ; Zn, 23.28.
so
20
£
120
T60
200
3
240
280
320
360
400
3
400
0.0024
o.oooo
0.01 I I
0.0204
0.0288
0.0354
0.0439
0.0514
0.0620
0.0772
0.1094
O.20IO
a
48o
500
520
540
56o
580
600
620
64o
10
Bent with
Breaking
Modulus
0.4110
0.5396
0.6989
0.9489
I. 10
;:£
£B
2.64
3-39
out breaki
load,/> =
3f rupture,
0.0059
Beam sinks
slowly.
io.347,4i9
11,260,425
11,964,201
12,978,117
13,081,592
....
1,513,020
13,407,355
12,967,651
11,902,213
9,448,876
5,714,246
....
755,634
ng. Remov
340 pounds.
R-*-^-
~zbd*~
edbar.*"
22,325.
0.2129
400 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXV.— Continued.
BAR NO. 6.
COMPOSITION.— Original mixture : Cu, 70; Zn, 30. Analysis: Cu, 71.20; Zn, 28.54.
1
fc, .
o >;
\
H
I
3D
h
Vt S
D U
LOAD.
y
SET.
If
LOAD.
|
SET.
-i G
& 53
*j
0 <
Q <
O J
H
0 J
Q
X H
Q
xl
Pounds.
Inch.
Inch.
P&ntdt.
Inches.
Inches.
o 6832
40
0.0172
6,691,260
556o
1.1092
so
1 20
0.0256
• •
8,991,379
580
10
i . 1467
160
"
ii 318 883
580
i . 3462
200
3
0.0501
"«4»5i995
600
620
i, "3,77i
640
2. 15
280
o 0680
* *
660
2 45
320
360
400
3
0.0794
0.0957
0.1268
Beam sinks
o 0408
",595,933
10,823,479
9,076,471
680
700
Bent wit!
Breaking
2.80
3-3°
lout breaki
load. P —
610,324
ed bar.
ng. Remov
TOO oounds.
44°
0.2147
480
0.4258
Modulus of rupture R — - 24 468
500
0.5396
2,660,088
BAR NO. 7.
COMPOSITION.— Original mixture : Cu, 65 ; Zn, 35. Analysis : Cu, 66.27 ; Zn, 33.50.
10
20
£
120
160
200
3
240
280
320
360
400
3
440
480
520
560
600
0.0028
0.0058
0.0124
0.0233
0.0317
0.0384
0.0466
0.0546
0.0642
0.0728
0.0836
0.0948
O.IIIO
°-I454
0.2128
0.4680
0.5958
6=1
640
660
680
700
720
£
Ilepeate
780
800
820
Bent wi
Bar rem
Breakin
Modulu
0.6734
0.8436
1.2058
1.41
!.59
1.79
2.04
d.2'34
2.84
l:l\
hout breal
oved.
Erload./) =
5 of ruptur
0.5538
o 003
0 OIT2
Beam sinks
slowly.
9,168,783
9,759,049
10,759,827
1,843,014
2,198,812
1,411,082
2,493'727
2,396,423
2,493,727
2,239,668
1,992,925
680,796
11,226,865
. 3-54
cmg.
= 820 pounds
«,*-*£.
2 bd*
= 28,459.
6,914,525
2,862,360
STRENGTH OF BRASSES.
401
TABLE LXXV.— Continued.
BAR NO. 8.
COMPOSITION.— Original mixture : Cu, 60 ; Zn, 40. Analysis : Cu, 60.94 ; Zn, 38.65.
LOAD.
Pounds.
£
120
160
200
10
g
%>
400
10
400
Left unde
sistance
10
440
480
520
560
600
10
640
720
800
10
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
|
o
SET.
MODULUS OF
ELASTICITY.
Inch.
0.0203
0.0291
0.0380
0.0447
°.°534
Inch.
0.0105
0.0135
lours ; defle
m unchange
0.0146
5,488,205
7^35,438
8,795,568
9,969,625
10,431,698
10,678,327
10,816,556
10,869.170
11,067,272
11,141,054
Pounds.
800
Resistanc
IO
840
880
900
920
940
960
980
1,000
I,IOO
Resistanc
Resistanc
Resistanc
pounds.
1,130
1,140
Randowr
maximui
pounds.
1 Bent with
Breaking
Modulus <
Inches.
0.5090
e decreasec
0.5275
0.9685
0.9885
I.OA
1.26
1.33
1 53
I .' 2
2.67
2 decreasec
j decreasec
; decrease
2.72
2.75
pressure s
n resistan
out breaki
load, /" =
)f rupture,
Inches.
in i hour to
0.3224
782 pounds.
2,535.9«>
0.0626
0.0721
0.0820
0.0906
O. IOOO
1,719,298
O.IO2O
r strain 18
to deflectic
:tion and re-
i.
in 30 sec. to 1,026 pounds,
in i m. to 1,020 pounds,
i in 17 hr. 30 m. to 990
,
0.1193
0.1290
0.1425
0.1585
0.1747
0.2555
0.5021
11,206,425
0.0283
0.3060
11,227,419
10,945,596
10,543,585
10,203,600
7,848,884
4,437,784
:rew about i inch further;
:e to rapid motion 1,160
ng.
i, 140 pounds.
*=7T^ = 38'968'
BAR NO. 9.
COMPOSITION.— Original mixture: Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44-44.
20
40
80
120
160
2OO
10
240
280
320
360
400
IO
440
a 80
520
560
600
10
640
680
700
720
800
10
800
0.0080
0.0148
0.0285
o . 0398
0.0505
0.0612
0.0800
0.0900
0.1004
O. I I1O
0.1317
0.1496
0.1790
0.247
0.2645
0.3306
0.3951
0.5060
0.5315
0.5833
0.8367
0.8581
0.0080
0.0213
7,888,340
8,194,687
8,800,055
9,247,321
9,538,189
8,756,005
9,080,354
9,302,585
9,466,607
8,864,649
8,584,370
7,826,643
7,069,010
860
880
900
920
94°
960
Resistanc
Resistanc
Resistanc
10
920
940
960
980
1,000
I,O2O
1,100
1,160
Crackling
1,180
1,200
Breaking
Modulus (
1.0364
1.1250
I-I953
1.2722
2,197,622
1.4647
e decrease<
e decrease
e decrease!
ii4785
J-S^S
1.5900
1.6815
1.7675
1.86
2.24
2.65
sound he?
2.79
Bar bent
from ui
load, P =
>f rupture,
i in 5 min. to
1 in 20 min. t(
i in 16 hr. to
1.2233
950 pounds.
) 942 pounds.
916 pounds.
1,653,646
1,433,283
0.1663
5,297,071
rd from bar.
and suppo
ider it.
i ,200 pounds
R 3/>/
rts slid out
= 42,463.
0.6250
4,839,294
2,790,663
* 2&*»
26
4O2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXV.— Continued.
BAR NO. 10.
COMPOSITION.— Original mixture : Cu, 50 ; Zn, 50. Analysis : Cu, 49.66 ; Zn, 50.14.
LOAD.
Pounds.
20
40
80
120
160
2OO
A slight ct
strain r<
being he
10
200
240
280
320
' 360
400
IO
440
480
520
560
600
IO
640
DEFLEC-
TION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLEC-
TION.
SET.
MODULUS OF
ELASTICITY.
Inch.
0.0065
0.0110
0.0219
0.0330
0.0429
o 0509
ackling so
mained 01
Id constan
0.0025
0.0509
0.0623
0.0773
0.1009
0-1337
0.1736
0.2220
0.2752
0.3291
0.3909
0.4568
0.5182
Inch.
Pounds.
680
720
760
800
IO
800
840
880
920
940
cracks we
appearanc
denly dec
beam was
580
10
Applied
reached
The crack
continue
was stra
held con
Breaking
Modulus
Inches.
0.5990
o. 6700
0.7647
0.6813
0.8713
0 9493
1.0613
1.1690
On applyir
•re heard,
e of break
reased, anc
found to 1
1-2570
Inches.
3,165,537
2,704,656
10,711,665
10,760,578
10,711,665
10,986,324
11,574,491
rd while the
le deflection
0.6699
und was hea
i the bar, tl
t.
2,318,265
everal slight
s no visible
istance sud-
ig the scale
5.
ig the stress s
but there wa
ng. The res
1 on balancii
>e 580 pound.
Beam sinks
slowly.
0.0816
11,347,832
10,670,093
9,342,185
7,931,600
6,787,347
i. "95
in, and the
when the ba
noticed first a
>ut the test vs
when the de
veral minute
940 pounds.
resistance
i.r broke.
1 200 pounds
rhile the bar
flection was
•s.
= 33,467.
stress aga
500 pounds
ing sound
d throughc
ned, even
slant for se
load, P =
of rupture,
5,838,341
4,654,4^
0.3165
3,869,144
ALLOYS OF COPPER AND ZINC.
BAR NO. 32.
Resistanc
3
751
800
820
is
880
900
920
&
e decrease
0.3364
0.3490
0.3583
0.3790
0.3948
0.4145
0.4343
0.4518
0.4669
0.4905
d in 22 hrs. to
0.1638
751 pounds.
980
1,000
1,020
0.5122
0.5302
0.5444
0.5718
0.6140
Broke in i
load, P=
of rupture
ling sound
he end of t
s held cons
niddle just a
1,100 pounds
*~i£=
noted at 520
tie test, even
Lant for sever
5,718,889
5,133.432
5 beam rose.
: 40,189.
rounds con-
ivhen the de
al minutes.
1, 080
I,IOO
Breaking
Modulus
The cracli
tinued till
flection wa
6,283,536
STRENGTH OF BRASSES.
403
TABLE LXXV.— Continued.
BAR NO. 33.
COMPOSITION.— Original mixture: Cu, 42.5 ; Zn, 57.5. Analysis: Cu, 43.36; Zn, 56.22; Pb,
0.38.
.
8>
.
H
o
LOAD.
e
E
SET.
§5
LOAD.
§
SET.
11
ft
s«
Q
§ w
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch
10
0.0030
360
_O_
20
0.0072
40
0.0164
5,95°, i 34
3
?!°7.?
0.0115
60
120
0.0279
°-°354
....
5,246,355
8,246,381
440
480
0.0850
0.0909
12,628,285
12,882,137
160
200
3
0.0421
0.0497
o 0063
9,271,468
9,817,123
520
54°
Breaking
0.0982
Broke jus
load, P=
t as beam ro
540 pounds.
I2,9l8,2II
se.
240
280
0.0556
1°,530,45I
Modulus of rupture, R= — 17,691.
320
0.0672
11,616,928
BAR NO. 39.
COMPOSITION.— Original mixture : Cu, 12.5 ; Zn, 87.5. Analysis: Cu, 12.12 ; Zn, 86.67;
Pb, 1.22.
10
20
40
80
120
160
200
3
240
280
320
360
400
3
440
480
520
560
O.OO22
0.0056
O.OI28
0.0234
0.0329
0.0430
0.0526
0.0641
0.0729
0.0818
0.0921
o. 1016
0.1115
0.1216
o. 1316
0.1421
600
Resistanc
pounds.
640
680
720
&
84o
880
Q2°
960
1,000
Breaking
Modulus
0.1528
e increase
0.1663
0.1796
0.2006
0.2116
0.2261
0.0148
:d in 10 mil
0.0114
11.986,725
mtes to 10
11,061,926
10,882,925
O.OOII
Beam sinks
slowly.
0.0064
8,982,413
9,826,913
10,484,031
10,695,338
10,929,173
10,762,079
11,040,112
11,244,489
11,235,332
11,316,427
11,342,857
11,346,204
",359,423
......
10,323,831
O.O378
0.2450
0.2624
0.2856
0.3124
Broke jus
load, P^
of rupture
9,854,991
t as beam ro
1,000 pounds
~&-
's.'s^YSgS
se.
- 35,026
BAR NO. 41.
COMPOSITION.— Original mixture : Cu, 2.5 ; Zn, 97.5. Analysis: Cu, 2.45 ; Zn, 96.43 ; Pb, 1.05.
20
o 1805
40
0.0154
8,117,624
480
0.2225
6,588,717
80
120
0.0362
10,124,235
560
0.3*37
5,452,091
160
0.0486
.. .
10,054,796
6OO
0-395°
4,639,208
200
o 0618
Q 88^ 064.
3
0.0051
60O
0 4007
240
280
0.0764
0.0932
630
Crack appeared in bottom of bar •
resistance decreased rapidly, and
bar broke.
Beam sinks
slowly.
9^75,542
320
360
400
0.1124
0.1352
0.1601
8,695,074
8,132,338
7,630,593
Breaking load, P= 630 pounds.
Modulus of rupture, R = — — = 23,137.
3
0.0498
404 MA TERIALS OF ENGINEERING— NON-FERROUS METALS.
237. The Method of Variation of Resistance with dis-
tortion is illustrated by strain-diagrams, several of which, as
obtained by tests in tension, are given in Figure 17. TLese
strain-diagrams are produced, in this case, by plotting the
record of test, making the ordinates of the curve proportional
to the load and the abscissas variable with the extension. In
LBS PER SO IN.
60:000
47.500
45.000
FIG. 17.— STRAIN-DIAGRAMS OF BRASSES.
TESTS BY TENSILE STRESS.
.01 .053 .03 .04 .05 .06 .07 .08 .09 .10 .11 .12 .13 14. .15 .16 .17 .1
ELONGATION IN PARTS OF ORIGINAL L7NGTH.
.19 ..20 .21 .22 .23 .24
preparing the test-pieces, the yellow alloys, Nos. I to 10, con-
taining less than 0.55 zinc, were easily turned in the lathe.
The white alloys, Nos. 12 to 15, 0.60 to 0.70 zinc, could not
be turned as they were too brittle to be worked ; these were
tested in the bar, unturned. The blue-gray alloys, Nos. 16 to
21, containing over 75 per cent, zinc, were more easily cut
than the first class and were tested in standard form and
size.
STRENGTH OF BRASSES.
405
Studying these diagrams, it is seen that, in some cases,
there appears the semblance of an elastic limit at not far
from one-half the maximum resistance. This is most easily
seen in the diagrams of Nos. 4 to 8. The tenacity varies
enormously, as,- for example, between Nos. 8 or 9 and 21.
Pounds
FIG. 1 8. — STRAIN-DIAGRAMS OF BRASSES.
Tests By Transverse Stress
.20 .40 .60 .80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 4.20 4.40 .4,60 4.86
Deflection'in Inches
The ductility is correspondingly variable, as illustrated by
the same cases. The elastic resilience is evidently greatest
with brittle alloys, as Nos. 1 1 A, 1 1 B; but the total re-
silience, as measured by the area covered by the curves, is
seen to be enormously greater in the strong and ductile
alloys, of which Nos. 8 and 9 (Muntz metal) containing 40 and
45 per cent, zinc are examples. Nos. 8, 9 and 10, which con-
tain from 40 to 50 per cent, zinc, are obviously by far the
4O6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
best compositions for general use, and the next best class
contains less zinc, as Nos. 4 to 7 (zinc, 20 to 35).
238. Strain-Diagrams obtained by Transverse Stress,
Figure 18, are illustrative of the same facts as were exhibited
by tests in tension. These are another set of bars similarly
graded from copper, 100, to zinc, 100. Here again a Muntz
metal, No. 30 (zinc, 40), is by far the best. Nos. 29 to 32,
form a valuable group (zinc, 37.5 to 50), and the lower num-
FIG. 19. — COMPARISON OF RESISTANCES.
Pounds
Ft.Lb.s.
COPPER95 90 85 80 75 70 65 60 65 60 46 40 35 30 25 20 15 10 5ZINC
Composition by Analysis
bers, containing less zinc, stand next in order. The smooth-
ness of these curves is remarkable.
No definite elastic limits are found here, although some
alloys, as Nos. 22-28, present indications of one nearly as well
defined as is sometimes the case with the best iron.
239. Comparisons of Resistances, as determined by the
several methods of test, are made by plotting the curves of
resistance side by side, as in Figure 19. No direct relation is
known to exist among these variations of load and of distor-
tion, but a close correspondence of general form is seen in the
diagrams.
The curves are so irregular that it is evident that further
STRENGTH OF BRASSES. 407
investigation will be needed to ascertain their exact form, as
determined by composition and unaltered by physical and
accidental conditions. The positions of the maximum and
the minimum are very nearly the same, as indicated by all
forms of test, and may be taken, for practical purposes, as at
zinc, 35 to 40, and at zinc, 60 to 65, respectively. All methods
of test concur in showing that the valuable alloys for the
ordinary work of the engineer lie on the copper side of the
maximum, where alloys are found which are tough as well as
strong. Those lying on the zinc side of the minimum, and
near the composition, copper, 15 to 20, zinc, 85 to 80, may
prove valuable as bearing metals and for castings or worked
parts not required to be of great strength ; their malleability
constitutes their prominent good quality.
The curves of resistances to various kinds of stress show
that they have a close relation depending upon the composi-
tion, in a portion of the series, but exhibiting a very different
law in other portions.
The alloys between 17.5 and 32.5 per cent, zinc by origi-
nal mixture, or between 16.98 and 30.06 per cent, zinc by
analysis, show a remarkable similarity in all properties. They
have all nearly the same strength, and nearly the same duc-
tility, the latter decreasing slightly as the percentage of zinc
increases. They are similar in color and appearance, so that
one could scarcely be distinguished from the other. Their
moduli of elasticity are nearly the same. The moduli of
rupture by transverse stress in this group varied from 21,193
to 26,930 pounds per square inch (1,490 to 1,893 kilogs. per
sq. cm.), these moduli being calculated from the loads which
caused deflections of 3% inches (9 cm.), as all of the bars bent
without breaking. The mean tensile strength of the two
pieces from each bar varied from 28,120 to 35,630 pounds per
square inch (1,977 to 2,505 kilogs. per sq. cm.), the lowest
figure being exceptional, and the piece possibly slightly de-
fective, as the next higher figure was 30,510 pounds (2,144
kilogs. per sq. in,).
All bars which contained less than 15 per cent, zinc by
mixture, or less than 11.06 per cent, zinc by analysis, were
408 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
defective, and their resistances were accordingly lower than
would be observed with sound castings. A few pieces of this
group gave higher results than the average, and these may
be taken as probably nearly the results which would be given
if the bars had been sound throughout.
Between the compositions containing 32.5 and 37.5 per
cent, zinc by mixture, or 30.06 and 36.36 per cent, zinc by
analysis, occurs a rapid increase of strength. The latter
alloy (63.44 copper, 36.36 zinc), had a modulus of rupture
of 43,216 pounds (3,038 kilogs. on the sq. cm.), and a mean
tenacity of 48,300 pounds per square inch (3,395 kilogs. per
sq. cm.).
Between the compositions containing 37.5 and 55 percent,
zinc by mixture, or 36.36 and 52.28 percent, zinc by analysis,
is another group of alloys, which contains that of maximum
strength by transverse, tensile, and torsional tests, but not by
compressive test, and higher than that of the first group.
The moduli of rupture vary from 33,467 to 63,304 pounds
(2,353 to 4,450 kilogs. per sq. cm.), the mean tenacity from
two-thirds to four-fifths as much. The figures decrease as
the proportion of zinc increases beyond that which is con-
tained in the alloy of maximum strength (58.49 copper,
41.10 zinc). The curves of test indicate that this composition
is nearly that of maximum strength, and probably within 2 per
cent, of the actual maximum. The alloy of maximum strength
contains about 41 per cent, of zinc. The compressive strength
of this group bears no relation to tensile, transverse, or torsional
strength, as it increases regularly with the increase of zinc ; and
the maximum compressive strength of all alloys of copper and
zinc is probably reached at an alloy containing more than 55
per cent of zinc. The ductility of this group has no relation
to strength, and always decreases as the proportion of zinc
increases.
The alloys containing less than 55 per cent, of zinc by
mixture (52.28 zinc by analysis), are the yellow metals or use-
ful alloys.
Between the compositions containing 55 and 60 per cent,
zinc by mixture (or 52.28 and 58.12 zinc by analysis) there is
Sl^RENGTH OF BRASSES. 4OQ
a rapid decrease of strength as well as a rapid decrease of
ductility.
Between the compositions containing 60 and 70 per cent,
zinc by mixture (or 58.12 and 66.23 Per cent, by analysis)
there is some uniformity of strength, these being the second
class, silver-white, brittle alloys. The moduli of rupture of
this group, and the tenacity are low.
Between the compositions containing 70 per cent, zinc by
mixture and pure zinc, comprising the bluish-gray alloys, the
curves of resistances gradually fall.
240. Resilience. — The resilience of pieces containing less
than 15 per cent, of zinc are uncertain in consequence of their
being defective. Two torsion pieces within this limit give the
maximum resiliences of 896.69 and 881.59 foot-pounds, these
pieces being also the most ductile under torsional test. From
the latter of these figures there is a rapid and comparatively
regular decrease of total resilience by torsion to alloy 38.46
copper, 61.05 zinc, only about ^.footh of the maximum. The
resiliences by transverse test, on the contrary, increase from
the defective bars to the bar of maximum strength, 58.49 cop-
per, 41.10 zinc, with considerable regularity, as the strength
increases, and then as the bars become of such low ductility
as to break, the resilience decreases, and the curve takes nearly
the same form as the curve of torsional resilience to the end
of the series.
From alloy 41.30 copper, 58.12 zinc, to 14.19 copper, 85.10
zinc, the resiliences are small, corresponding with the combi-
nation of low strength and low ductility. At alloy 7.20 cop-
per, 92.07 zinc, there is a second maximum of resilience, the
very large increase of strength of the alloy over those of mini-
mum strength contributing to give this alloy more resilience
than cast zinc, although the latter has much the greater duc-
tility.
241. Limit of Elasticity. — In the table of results of tests,
figures are given representing the transverse load at the ap-
parent elastic limit and corresponding modulus I R = — J-T^J*
The relation between the elastic limit and ultimate strength
410 MATERIALS OF ENGINEERING— NOX-FERROUS METALS,
appears to vary considerably. The percentage ratios by trans-
verse tests appear to be greater than those by the other
methods of test.
In the more ductile alloys, containing less than 50 per
cent, of zinc, the elastic limit is generally from 20 to 50 per
cent, of the ultimate strength ; as the percentage of zinc in-
creases beyond 50 per cent., and the alloys become more brittle,
FIG. 20.— MODULI OF ELASTICITY AND SPECIFIC GRAVITY.
(From Transverse Tesls)
COPPER^ 9*> 85 80 75
ft 000 000
~~\'
3 -
14 000 000
T
12 000 000
]ei
->£
-— "
. "-
^
•^ —
— -r-r
•^
f**^
^>-
^
Co ooo ooo
:
X
0 on
w
X
8.80
8 60
'
T^~
-^
.:;::;
8 40
LlL
">
^
8 20
n
~^
^
:'-E
8.00
7.80
>\
\,
-::!
x
- i;
\
x
740
1
\
IT
!
^
il
tf'10
-.
v^
^
_:
^
70 65 00 55 50 45 ±0 35
Composition by Analysis
25 20 15 10 5 ZINC
the elastic limit is not clearly defined, but appears to approach
more nearly to the ultimate strength in tensile than in other
tests.
In brittle alloys, containing from 56.22 to 85.10 per cent
zinc, the elastic limit is not reached until fracture takes place.
From 85.10 per cent, to pure zinc, the ratio decreases by
transverse tests, while in tensile tests the ratio apparently re-
mains at loo per cent, till 96.43 per cent, zinc is reached. In
torsion tests the elastic limit begins to be less than the ulti-
mate strength after 86.67 per cent, zinc, the ratio decreasing
as the percentage of zinc increases.
STRENGTH OF BRASSES. 41 1
242. The Moduli of Elasticity of the copper-zinc alloys
are variable according to a law which is probably nearly repre-
sented by the upper curve in Figure 20. The modulus for
copper is low, and the figure gradually rises as zinc is added,
until passing zinc 25, it falls again, passing a minimum at
about zinc 50, and a second maximum not far from zinc 75,
and falls off rapidly to a minimum at pure zinc. Further in-
vestigation is needed to determine to what extent these fluct-
uations are due to chemical and what to physical causes.
The Author is inclined to believe that sound castings contain-
ing large amounts of copper would give higher figures.
The moduli of elasticity given in the above table were se-
lected from the records of test by transverse stress.
The average figure for the alloys is nearly 13,000,000
(913,900 kilogs. per sq. cm.). The variation of the figures of
bars of different composition does not have any relation to
density, strength, or other mechanical property, but follows a
law of its own.
There appears to be an increase of the modulus with in-
crease of percentage of zinc up to the alloy containing 16.98
per cent, of zinc. It then appears to be nearly uniform from
16.98 to 36.36 zinc. From 36.36 zinc to 44.44 zinc there is a
regular and rapid decrease, and from 44.44 zinc to 52.28 zinc
there is a regular and rapid increase. This break, almost a
cusp in what might otherwise be a regular curve, is indicated
by all observations between the limits of 36.36 and 52.28 zinc.
The increase in the modulus continues from the alloy con-
taining 52.28 per cent, zinc to that containing 66.23 Per cent,
zinc. The latter alloy gives the maximum modulus of the
series. From this point there is a rapid decrease to pure
zinc, which gives the minimum modulus.
The bars which make this break include the strongest bars
of the series, and those which exhibited the phenomena of
irregularity in increase of deflection under transverse stress
and of emitting the crackling sound (cry of tin) when held at
a constant deflection. They also include metals of a wide
range of ductility and hardness, and of a structure varying
from fibrous to coarsely granular.
412 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
243. The Curve of Specific Gravities is presented on the
lower part of the same figure, under that of the moduli of
elasticity. This curve is not as smooth as that given for the
bronzes, and it may ultimately be found necessary to revise it
to some extent. The general method of variation is very
similar to that given for copper-tin alloys. Its equation may
be taken as approximately,
D = 7 + 0.019 C,
in which D is the specific gravity and C the percentage of
copper. It is not, however, a straight line, but has probably
FIG. 2i.— COMPARATIVE DUCTILITY.
TRANSVERSE
DEFLECTION
TENSILE
ELONGATIOH
2:20 0.14
COPPER9:
70 65 60 65 50 45 40 35
Composition by Analysis
the same smooth and moderate curvature observed in that
given for the bronzes. A smooth curve osculating that here
given on the upper side of the latter, is perhaps the true curve.
It would terminate at very nearly or quite S. G. = 9 on the
copper side, and at S. G. = 7.15 at the zinc end.
244. Comparisons of Ductility of the copper-zinc alloys
are graphically exhibited in the above figure, as determined
by the several methods of test. It is seen that it varies in the
opposite direction to the change of strength with variation of
composition and to be different in its distribution from that
STRENGTH OF BRASSES. 413
observed in the copper-tin alloys. All bars containing be-
tween 16.98 and 38.65 per cent, zinc have a high degree of
ductility, the mean extension of the two pieces of each bar
varying from 20.67 to 38.5 per cent. With the increase of
zinc beyond 38.65 per cent, the ductility decreases till 52.28
per cent, zinc is reached, the mean extension of the alloy of
this composition being only 0.79 per cent., or but little more
than one-fiftieth of the maximum. From 52.28 to 70.17 per
cent, zinc, the elongations could not be determined, most of
the pieces being tested in their original rectangular sections.
Their extensions were, without doubt, much less than 0.79
per cent., as the test-pieces appeared nearly as brittle as glass.
From 77.43 to 96.43 per cent, zinc the elongations very slowly
increase, that of the former composition being only 0.12 per
cent., and that of the latter 0.88 per cent.
The form of the curve and one test showing an exception-
ally high ductility of 607 degrees angle of torsion, or an ex-
tension of 2.5011 (No. 3, 89.80 copper, 10.06 zinc), indicate
that the maximum ductility of the alloys of copper and zinc
is found among alloys containing small quantities of zinc.
From 16.98 to 61.05 zmc there is a very regular decrease of
ductility, the latter having an extension of 0.00002, or only
about T2T?oTo-th of the maximum. From 61.05 to 88.88 zinc
there is a uniform want of ductility, the figures of extension
varying from 0.00002 to o.oooii. From 88.88 zinc to pure
zinc, the ductility increases.
245. A Summary of many of the results of the tests which
have been described will be found included in the table al-
ready given at the end of Chapter V., in which the brasses
are described.
When brasses are desired to work freely, as with auto-
matic machinery, one or two per cent, of lead should be
added ; giving freedom of working and ease in cutting such
as cannot be attained otherwise. Such compositions are
called "leaded brass."
Bismuth in brasses causes hot- and cold-shortness, fire-
cracks, and general deterioration.
CHAPTER XI.
STRENGTH OF KALCHOIDS AND OTHER COPPER-TIN-ZINC
ALLOYS.
246. The Kalchoids. — The bronzes and brasses were not
distinguished by early Greek and Latin writers, who applied
the same names to both (Greek, Kalchos ; Latin, Aes.). It
has also been common to add to the copper-tin, or bronze,
alloys small proportions of zinc, and lately, to the copper-zinc
alloys, or brasses, small quantities of tin, thus forming an in-
termediate collection of indefinite number and proportions, to
which may be here applied the indefinite terms of the ancients,
and which may be called the kalchoids, or kalchoid alloys.
These and solders and other copper-tin-zinc alloys naturally
fall into one group.
The effect of substituting a small quantity of zinc for tin
in making the bronzes is not perceivable except as making
them a little less subject to " cold shuts," or blow-holes and
similar defects, making them a little softer and a trifle weaker
and giving them slightly better working qualities when
turned in the lathe or otherwise shaped with cutting tools.
The effect of substituting a small proportion of tin for zinc in
the brasses, however, is very marked, causing increased
hardness, strength, rigidity and elasticity, and, if the propor-
tions of copper and zinc are about equal, making the alloy
too hard and brittle to work.
In general, the effects of the two metals, zinc and tin,
upon copper are similar, but that of adding tin is much more
observable than that of introducing zinc. It was found in
collating the results of investigations made by the Author for
the U. S. Board and in other researches, that the effect of one
part tin is nearly equivalent to two parts of zinc.
These facts are well illustrated in the account of that work
STRENGTH OF KALCHOIDS.
415
to be presented in the present chapter. They are well shown
also, in experiments on "sterro-metal."
247. Sterro-metal, tested at Woolwich, exhibited a te-
nacity somewhat variable with composition, but always con-
siderable, as seen below.* Its stiffness and resistance to
abrasion were also found to be very great. The tenacity may
be taken at an average of 60,000 pounds per square inch
(4,218 kilogs. per sq. cm.), its elastic limit at one-half that
amount, and its elongation at 0.07. The test pieces used
were three diameters long.
TABLE LXXVI.
TENACITY OF STERRO-METAL.
Breaking
weight, Ibs.
per square
inch.
Kilogs. per
square cm.
Ultimate
elongation
at breaking
point in
inches.
Treatment.
Mixture.
60,020
4,213
.1
as received.
Austrian.
46,060
3,386
•05
)
Copper, 60 ; zinc, 39 ;
[ cast in sand.
iron, 3; tin, 1.5.
43,120
3,032
.015
)
54.220
52,080
3,8i9
3,662
.016
.02
cast in iron.
j cast in iron and
( annealed.
Copper, 60 ; zinc, 44 ;
iron, 4 ; tin, 2.
62,720
4,4io
•045
forged red hot.
70,806
A Q78
) cast in iron and
*72 8jX
if)V/u
C T2I
\ forged red hot.
/•^»<-J'f 3
76,l6O
D, •«••*•«•
5 ore
Copper, 60 ; zinc, 37 ;
5 J 3D
*
iron, 2 ; tin, i.
84 Q2O
c,o8<
Copper, 60 ; zinc, 35 \
\JL^^\^£t\J
3>VW3
iron, 3 ; tin, 2.
6O,48O
76,160
84,920
4,252
5,355
5,985
....
after simple
fusion,
forged red hot.
drawn cold.
j Copper, 55.04 ; spelter,
)• 42.36 ; iron, 1.77 ;
tin .83.
62,720
4,4io
after simple
j
fusion.
73,68o
5,040
.
forged red hot.
drawn cold and
reduced from
Copper, 57.63; spelter,
• 40.22 ; iron, 1.86 ;
82,S8o
5,827
....
loo to 77 trans-
tin, 0.15.
verse sectiona
I
area.
•
* •' Strength of Materials ;" Anderson, Lond., 1872.
41 6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
This greater tenacity, as compared with brass and Muntz
metal, is probably partly due to the presence of iron, but
largely also to the one or two per cent. tin. As will be seen
later, the Author has obtained higher figures by the use of
tin alone.
248. The Copper-Tin Zinc Alloys were made the sub-
ject of a special and systematic investigation, at the request
of the Committee on Alloys of the U. S. Board of 1875, with
a view to the determination, not simply of the strength and
other properties of specific combinations, but to ascertain the
law governing the variation of such useful qualities with vari-
ation of composition, in such manner that, by the study of a
limited number of these alloys, the properties of all possible
combinations of the three metals might be fully determined.
Before entering upon this investigation it, therefore, became
necessary to devise a plan and to invent a method of research,
which should enable the Author so to choose the set of alloys
to be studied as to make their number a minimum, while so
fixing their proportions as to distribute them with a satisfac-
tory degree of uniformity over the whole field to be ex-
plored, thus making the research complete and productive of
a maximum result at minimum cost of time, labor, and
money.
249. The Plan of Investigation, if it could be made thus
effective, should evidently lead not only to the determination
of the strength and elasticity, ductility and resilience, and
other important properties of all possible alloys of copper with
zinc, copper with tin, and tin with zinc, and of all copper-tin-
zinc alloys, but should also reveal the composition of the
alloy of maximum strength or other quality, or combination
of qualities, that could possibly be formed and that man can
make, using these elements. Such a plan was devised by the
Author. Its principle is as follows : *
In any equilateral triangle, B, C, D, Fig. 22, let fall per-
pendiculars from the vertices to the opposite sides, as for
* On a New Method of Planning Researches, etc., by R. H. Thurston. Proc.
Assoc. for Advancement of Science, vol, xxvi. Trans. Am. Soc. C. E., 1881.
Also, for later work, by A. Wright, Proc. Roy. Soc., 1891-4.
STRENGTH OF KALCHOIDS. 417
example, C E. From any point within the
triangle, A, let fall perpendiculars A G,
A H,ATF, and draw A B, A C, Z77 to
the vertices, thus obtaining three triangles,
A B D, ABC, A CD; their sum is equal
to the area of the whole figure BCD.
Now we have, since the triangle is equilateral, and
CE x BD _ A F x B D AG x B C AH x CD
" I ~T~ 4" ;
and
which follows wherever the point A may be situated ; it is
true for every point in the whole area BCD. Assuming
the vertical C E to be divided into 100 parts ; then A F +
Z77 + TG = loo and 4.F, 4JL, ^L, measures the rela.
IOO IOO IOO
tion of each of the altitudes of the small triangles to that of
the large one.
But we may now conceive the large triangle to represent
a triple alloy of which the areas of the small triangles shall
each measure the proportion in which one of the constituents
enters the compound, and
BCD = loo per cent. = (~AF + ~A~G + AH) B D, or
CE = TOO per cent. = AF + AG+AH per cent, and
the altitude of each small triangle measures the percentage
of some one of the three elements which enter that alloy
which is identified by the point. Thus every possible alloy
is represented by some one point in the triangle BCD, and
27
4-1 8 MATERIALS OF ENGINEERING— NON-FERROUS METALS-.
every point represents and identifies a single alloy, and
only that. The vertices B, C, D, in the case to be here con-
sidered, represent respectively, copper = 100, tin = 100,
zinc = ioo.*
250. Alloys Chosen for Test. — Thus, having determined
a method of studying all possible combinations, the Author
next prepared to examine this field of work in the most
efficient and complete manner possible, with a view to deter-
mining, by the study of a limited number of all possible cop-
per-tin-zinc alloys, the properties of all the numberless, the
infinite, combinations that might be made, and with the hope
of detecting some law of variation of their valuable qualities
with variation of composition, and thus ascertaining which
were the most valuable for practical purposes.
With this object in view, the triangle laid down to repre-
sent this research, was laid off in concentric triangles, Fig. 23,
varying in altitude by an equal amount — 10 per cent. — on
which were laid out the following series of alloys :
FIG. 23.
* The same general principle may be employed, as stated in the discussion
before the Am. Assoc. for Advancement of Science (Nashville meeting, 1877),
where four variables are studied. It has been so employed by Professor Howe
(Trans. A. I. M. E., Feb. 1898, vol. xxviii, pp. 346, 894: "Use of Tri-axial
Diagram and Triangular Pyramid "). Professor J. Willard Gibbs proposed
the use of the principle in still another field in 1876 (Trans. Conn. Acad., 1876,
p. 108). It is in constant use in the laboratories of Cornell University.
STRENGTH OF KALCHOIDS.
TABLE LXXVII.
SCHEDULE OF COPPER-TIN-ZINC ALLOYS TESTED.
419
COPPER.
ZINC.
TIN.
COPPER.
ZINC.
TIN.
IO
IO
80
30
40
30
10
20
70
30
50
2O
10
30
60
30
60
IO
10
40
50
40
10
50
10
50
40
40
20
40
10
60
30
40
30
30
10
70
20
40
40
20
10
80
10
40
50
10
20
10
70
50
IO
40
20
20
60
50
20
30
20
30
50
50
30
20
20
40
40
50
40
10
20
50
30
60
10
30
20
60
20
60
20
20
2O
70
TO
60
30
IO
30
10
60
70
10
20
30
20
50
7°
20
10
30
30
40
80
IO
10
These alloys were first tested in the Autographic Record-
ing Machine, and their strain-diagrams carefully studied. It
was found that only a few were of value, and that the alloys
represented by that part of the field lying on the tin-zinc side
of a line running from copper = 70, tin = 30, zinc — o, to
the point copper = 40, zinc = 60, tin — o, were too soft or
too brittle and weak to be useful. The research was now re-
stricted to the examination of alloys lying nearer the point
copper = 100, i.e., the upper vertex of the triangle as seen in
the figure, and all such alloys were tested by tension, com-
pression, and torsion, and by transverse stress.
251. Details of the Work. — In the study of these copper-
tin-zinc alloys, the same general method of experiment was
adopted as in the investigations of the brasses and the
bronzes already described.*
To ascertain what results would be obtained by casting
together brass and bronze of known properties, the first series
* The observer entrusted with this work, under the direction of the Author,
was Mr. M. I. Coster, M. E.
420 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
of ternary alloys was prepared in proportions based upon results
obtained in the earlier researches relating to copper-tin and
copper-zinc alloys as the strongest, the weakest, the most and
the least resilient alloys respectively ; and by various com-
binations of these, twelve alloys were obtained.
This constitutes the first series. No. 5 (Cu 88.135, Sn
1.865, Zn 10) was made up of the most resilient bronze and
brass ; its resilience was less than that of either of its com-
ponents. No. 6 (Cu 45, Sn 23.75, Zn 3T-25), composed of
the least resilient bronze and brass, was less resilient than the
brass, but more so than the bronze. No. 7 (Cu 66.885, Sn
1.865, Zn 31.2), formed of the most resilient bronze and the
least resilient brass, was much less resilient than the bronze,
but considerably more so than the brass. No. 8 (Cu 66.25,
Sn 23.75, Zn 10) was made of the least resilient bronze and
the most resilient brass. It was less resilient than either the
bronze or the brass. The greatest resistance to torsion of
all the bars of the series was exhibited by No. 7, and the
mean of its torsional moments exceeded that of all the others.
It was of a more homogeneous structure, and may be con-
sidered the best alloy of the series. No. 5 was the most
ductile and the most resilient. No. 12 (Tobin's alloy, Cu
58.22, Sn 2.30, Zn 39.48) was shown by all the tests to be
the strongest alloy. It exceeded good wrought iron in
strength, and was sufficiently resilient to resist shocks. Its
modulus of elasticity, as calculated from the transverse test,
is 11,500,000 (metric, 808,450). From the results obtained, it
is evident that it does not necessarily follow that two alloys
which are separately good and strong, or poor and weak,
will, when cast together, give an alloy which is similarly
strong or weak.
A second series was next tested, to afford a general survey
of the field containing what were known to be good alloys
and to locate approximately the position of the best com-
positions.
In this set, 36 alloys were made by all possible combina-
tions obtainable by a difference of 10 per cent, in the three
metals. As a rule, the bars of this series were not as strong
STRENGTH OF KALCHOIDS. 421
as those of the first series ; this may have been due to the
fact that the other bars were cast under greater pressure.
It was noted that if the amount of tin does not exceed 40
per cent., the alloys are strengthened by an increase of copper
up to 20 per cent. If further addition of copper is made the
alloys become brittle, and when the copper amounts to 50
per cent., compositions are obtained which are practically
worthless. If more copper is added the alloys increase in
strength until a maximum is attained for the greatest per-
centage of copper in their series, i. e., 80 per cent. When the
amount of tin exceeds 40 per cent, the alloy becomes weaker
as the percentage of copper is increased. Up to 20 per cent.
of copper, an increase of tin causes a decrease of strength and
an increased ductility. Between 20 per cent, and 40 per
cent, of copper, the alloys become stronger for an increase of
tin up to 20 per cent. They then become weaker as the tin
is further increased. When the amount of copper exceeds 40
per cent, an increase of tin again appears to weaken the alloy ;
this is only true when the least quantity of tin amounts to 10
per cent., as in this series. The results of tests of this series
show that more than five-sixths of the alloys in the field here
explored are comparatively worthless.
A third series of 24 alloys was next made for the purpose
of locating the best alloys still more precisely, and to deter-
mine the properties of those lying within the now greatly
restricted field of investigation, which had now been con-
tracted to a small fraction of the total area.
A line was drawn from 45 per cent, copper on the zinc
side of the triangle to 72.5 per cent, of copper on the tin side.
These points represent the percentages at which the marked
change of color and of strength in the brass and bronze alloys
takes place. The alloys of this series were all located in that
portion of the field containing all the more useful composi-
tions and were made to vary in composition by 5 per cent.
The castings of this and succeeding series had smoother sur-
faces than those preceding. Some volatilization of zinc took
place during the pouring of the molten metal in the first
three numbers of the series. A great difference was noted in
422 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
the results obtained from the upper and lower ends of the
bars ; the upper end giving the best figures. The difference
between the strain-diagrams of these two portions of the bar
was such that the former in one case had an ordinate of 0.92
inch at the elastic limit and a maximum ordinate of 1.76
inches, while the other end had for its ordinate at the elastic
limit 1.38 inches and for a maximum ordinate 1.56 inches.
The general laws exhibited by the curves representing
the properties of alloys of copper, tin, and zinc, were ap-
proximately determined from the tests of this series. For
a certain amount of copper (when this exceeds 50 per
cent.) an addition of tin increases the brittleness, while
zinc increases the ductility of the alloy. If the amount
of copper is increased it is necessary also to increase the
tin in a certain ratio in order to obtain an alloy of about
the same percentage of ductility. It was shown by the tests
of this series that if the composition has 80 per cent, of
copper, 10 per cent, of tin will make it quite ductile, while
15 percent, of tin will render it rather brittle. Hence the
amount of tin necessary to make a strong alloy, when there is
80 per cent, of copper, lies somewhere between 10 per cent,
and 15 per cent., and an alloy composed of Cu 80, Sn 12.5,
Zn 7.5 was taken as very nearly representing the best pro-
portions.
Next, a fourth series was made. This series consisted of
but five alloys, which were chosen without regard to regularity,
but to determine doubtful points previous to the preparation
of the final series. No. I (Cu 55, Sn 0.5, Zn 44.5) contained
but 0.5 per cent, of tin, and is the only instance in the entire
investigation where so small an amount of any of the metals
was introduced in an alloy. This was done in order to ascer-
tain the effect of so small a percentage when added to an
alloy of known properties. This alloy was brass (Muntz
metal, nearly), and 0.5 per cent, of tin was substituted for
zinc, thus leaving but 44.5 per cent, of zinc. The smallest
quantity of zinc in any bar of the series was 2.5 per cent, in
No. 5 (Cu 82.5, Sn 15, Zn 2.5). The difference in ductility
between the two ends of the bars was more marked in No. 2
STRENGTH OF KALCHOIDS. 423
(Cu 67.5, Sn 5, Zn 27.5) than in any other alloys thus far
tested. The upper end, No. 2 A, was turned in the auto-
graphic machine through an angle of 70.8°, while the lower
end, B, broke after it was turned through 7.5°, the latter
being only about 10 per cent, of the former. This difference
was exhibited, in a more or less marked degree, by all the
bars of this series.
Comparing the data thus obtained by test of the several
sets of alloys made as above, it became evident that all the
most useful alloys are located between the line drawn from
88 per cent, of copper on the bronze side of the triangle to
65 per cent, of copper on the brass side, and from 83 per
cent, of copper on the bronze side to 55 per cent, on the
brass side. Twelve alloys in this part of the field were next
made, varying by 2.5 per cent., omitting those which had
already been tested and a few not absolutely necessary to the
determination of the law of variation of strength. The re-
sults obtained fully confirmed previous conclusions. It was
found that, in nearly all cases, the upper portion of the bar
was considerably more ductile than the lower and also gener-
ally stronger. All the alloys of this series were strong ; the
strongest, No. I (Cu 60, Sn 2.5, Zn 37.5), had a mean maxi-
mum torsional moment of 216 foot-pounds (tenacity about
40,000 Ibs. or 2,892 kilogs.), and the weakest, No. 7 (Cu 72.5,
Sn 10, Zn 17.5), 122 foot-pounds (tenacity about 24,000 Ibs.,
or 1,672 kilogs.). All the alloys located between the lines
forming the boundaries of the set of compositions in this
series are useful and strong. Commencing with the strong
brasses on one side of the triangle, greater strength is ob-
tained when any appreciable amount of tin is added ; as the
quantity of tin is increased, the alloys continue to be superior
in strength to either the brasses or the bronzes ; but their
strength gradually decreases with the diminution of the
amount of zinc, if the alloy contains .more than 60 per cent,
of copper, until we obtain strong bronzes on the other side of
the field. An addition of tin for the same amount of copper,
if this addition does not exceed 30 per cent., increases the
ductility of the alloy. In alloys containing 40 per cent, of
424 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
copper a substitution of a moderate quantity of tin for zinc
does not seem to affect the ductility. If the alloys contain
more than 40 per cent, of copper, an increase of tin causes a
decrease of ductility. The most ductile alloy was No. 8 B,
2d series (Cu 10, Sn 80, Zn 10), which had an angle of tor-
sion in the autographic machine of 418.4° ; no other alloy
tested contained such a large quantity of tin. From the per-
centage of extensions of the alloys having a torsional moment
of more than 150 foot-pounds, and strength of more than
30,000 pounds per square inch (2,109 kilogs. per sq. cm.), four
curves of maximum strength with a percentage of extension
have been constructed (Fig. 27). The lowest curve thus
plotted has an extension of 0.03 per cent, and connects the
points representing the strong brittle alloys. It starts at 43
per cent, of copper on the brass side and cuts the bronze side
of the triangle at 77 per cent, of copper. The other curves
have an extension of 3, 7.3, and 17 per cent, respectively.
They all appear to converge to a point on the right of the
brass Gide and agree nearly with arcs of circles of about 7
inches radius on the scale of the figure. By means of these
curves of extension, alloys of different degrees of ductility can
be selected. The effect of tin upon alloys of copper and zinc
within limits may be compared to that of carbon on wrought-
iron. Commencing with brass of about 55 per cent, of copper,
which is of itself ductile and strong, we obtain by the addition
of a small percentage of tin an alloy of much greater strength,
having a higher modulus of elasticity, but not quite as ductile.
By further addition of tin, up to about 2.5 per cent., the alloy
becomes gradually less ductile, but it increases in strength.
But if more tin is added, we obtain compositions which be-
come more brittle as the tin is increased, and at the same
time decrease in strength. A slight modification of propor-
tions often causes very great changes in the properties of the
alloys, as in No. I, 4th series, where 0.5 per cent, of tin,
added to ordinary brass produced an alloy stronger than
wrought iron.
The facts thus brought out are best exhibited by the pro-
file map and the model which are to be presently described.
STRENGTH OF KALCHOIDS.
252. The Method of Exhibiting and Recording Results,
which, as devised by the Author for this case, was intended
so to present the data secured in the manner described that
it could be seen, at a glance, what law, if any, controlled the
FIG. 24. — COPPER-TIN-ZINC ALLOYS.
variation of strength, or of the quality, with change of com-
position, and that the investigator could readily determine
where to seek the alloy possessing a maximum of any quality,
desirable or otherwise, should it happen, as would in all prob-
ability be the case, that that alloy had not been included
among those studied during the investigation. The plan
426 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
finally adopted was novel but as thoroughly satisfactory as
was that of laying out the work. It was the following :
The figures obtained by the test of alloys studied were
inserted upon a triangular plan, each in its place as deter-
mined, in the manner described in Art. 249, for that compo-
sition.
When the figures thus obtained had been entered on the
triangular map, lines of equal strength, of equal ductility, or
of equal resistance could be drawn, as in topographical work
lines of equal altitude are drawn, and the map became thus a
useful representation of the valuable qualities of all possible
alloys.
Figure 24 represents such a map * of all copper-tin-zinc
alloys. The scale of altitudes is obtained by considering the
relation of tension to torsion resistance as 25,000 pounds per
square inch (1,758 kilogrammes per square centimetre) foi
each 100 foot-pounds (13.82 kilogrammetres) of torsional mo-
ment for the standard test-specimen, which specimen was
turned to a standard gauge, and made ^ inch (1.84 cm.) di-
ameter and i inch (2.54 cm.) long in the cylindrical part ex-
posed to strain.
These facts were also exhibited by another method de-
vised by the Author ; thus :
Upon a triangular metal base, laid off as above, erect a
light metallic staff by drilling a hole for its support at each
point laid down as representative of an alloy tested ; make
the altitude of each of these wires proportional to the strength
of that alloy. There is thus produced a forest of wires, the
tops of which are at elevations above the base-plane propor-
tional to the strengths of the alloys studied. Similar con-
structions may be made to represent the elasticity, the duc-
tility, or any other property of all these alloys. Next fill in
between these verticals with clay, or better, with plaster, and
carefully mould it until the tops of all the wires are just vis-
ible, shining points in the now smooth surface of the model
* Reports of U. S. Board testing Iron, Steel, etc. Washington, 1878-1881.
The Strongest of the Bronzes ; R. H. Thurston. Trans. Am. Soc. C. E. l88l,
no. ccxlv.
STRENGTH OF KALCHOIDS.
427
The surface thus formed will have a topography characteris-
tic of the alloys examined, and its undulations will represent
the characteristic variations of quality with changing proper
tions of the three constituents. This was made for the Author,
FIG. 25.— MODEL OF COPPER-TIN-ZINC ALLOYS.
Zn,
and was cast in an alloy of maximum tenacity, the plaster
cast made as above being used as a pattern.
Figure 25 is a representation of this model made from a
photograph.
253. General Deductions.— The remarkable variations of
quality here so strikingly shown attracted attention, and a
further investigation was made.
These alloys were purposelv made without other precau-
428 MATERIALS OF ENGINEERING— NON-FERROUS MRTALS.
tions than those observed by every founder, and without using
deoxidizing fluxes.
The data obtained were consequently quite variable, and
the result of this work indicated that the same alloy, especially
where the proportion of copper is great, may give very differ-
ent figures accordingly as it is more or less affected by the
many conditions that influence the value of all brass-foundry
products.
Some variations in the model are probably due to such
accidental circumstances. But, allowing for minor vari-
ations, it is evident that the alloys of maximum strength are
grouped, as shown in Figures 24 and 25, about a point not
far from copper =55, zinc = 43, tin = 2. This point is en-
circled in the map, Figure 24, by the line marked 65,000 pounds
per square inch (4,570 kilogs. per sq. cm.) tenacity, and repre-
sented on the model, Figure 25, by the peak of the mountain
seen at the farthest side — the copper-zinc side.
This is the strongest of all bronzes, and an alloy of this
composition, if exactly proportioned, well melted, perfectly
fluxed, and so poured as to produce sound and pure metallic
alloy, with such prompt cooling as shall prevent liquation, is
the strongest bronze that the engineer can make of these
metals. The " naval bronzes " now usually approximate this
composition.
The Author finally made this alloy, and of it constructed
the model represented in the last figure. It is a close-grained
alloy of rich color, fine surface, and takes a good polish. It
oxidizes with difficulty, and the surface then takes on a pleas-
ant shade of statuary bronze green.
The exact composition of this, which the Author has called
the " maximum alloy," was not considered as fully determined
by this preliminary investigation. The metals used in making
it were commercial copper, tin, and zinc, and the methods of
mixing, melting, and casting were purposely those usual in
the ordinary brass foundry, and necessarily subject to some
uncertainty of result.
The precise location of this " strongest of the bronzes'1
was intended to be made in an independent and later research,
in which chemically pure metals, more carefully handled, and
STRENGTH OF KALCHOIDS. 429
especially well fluxed with phosphorus or other effective
flux, should be used. This research was carried out several
years later, under the eye of the Author, and an account of it
is given later.
Testing the alloy above referred to, it was found to have
considerable hardness and but moderate ductility, though
tough and ductile enough for most purposes ; it would forge
if handled skilfully and carefully, and not too long or too
highly heated, had immense strength, and seemed unusually
well adapted for general use as a working quality of bronze.
In composition it is a brass, with a small dose of tin.
The alloy made as representing the best for purposes de-
manding toughness, as well as strength, contains less tin than
the above composition (Cu, 55 ;Sn, 0.5 ;Zn, 44.5).
It had a tenacity of 68,900 pounds per square inch (4,841
kilogs. per sq. cm.) of original section, and 92,136 pounds
(6,477 kilogs.) on fractured area, and elongated 47 to 5 1 per cent,
with a reduction to from 0.69 to 0.73 of its original diameter.
No exaltation of the normal elastic limits was observable
during tests made for the purpose of measuring it if noted.
This alloy was very homogeneous, two tests by tension giving
exactly the same figure, 68,900. The fractured surface was
in color pinkish yellow, and was dotted with minute crystals
of alloy produced by cooling too slowly. The shavings pro-
duced by the turning tool were curled closely, like those of
good iron, and were tough and strong.
254. The Strain-Diagrams from the autographic ma-
chine (No. 1,001) are shown \\\ facsimile in the accompanying
engraving. The tenacity, as estimated from the resistance
to torsion, is nearly equal to that determined by direct ex-
periment, and four samples tested give strain-diagrams that
are all nearly precisely alike. They exhibit an ill-defined
elastic limit, e, at about f their ultimate resistance, and about
the same as a piece of excellent gun-bronze (Cu, 90; Sn, 10
per cent.), 1,252 A, the strain-diagram of which lies beside
them in dotted line. The elastic resilience, which is meas-
ured by the area of the curve up to e, is superior to that of
the gun-bronze, and the elastic range is seen to be greater, on
430 MATERIALS OF ENGINEERING— NON-FERROUS METALS*
inspection of the " elasticity lines," e e. In ductility they
excel 1,252 A, somewhat, as is seen by comparing 1,001 A
with 1,252 A. Their toughness is shown by the great area
and the altitude of the curve ; their excellence of quality is
also shown by its smoothness of outline. The homogeneous-
ness of structure is exhibited by the similarity of the diagrams
and by the smoothness of the bend at e, which marks the
elastic limit.
At /"is a depression of the normal line of elastic limits
produced by 17 hours intermission of distortion under the
load there carried. This slight depression marks this alloy as
one of the "tin class."
Diagram 1,252 B is given by a fine gun-bronze; 1,001 x h
an hypothetical diagram, such as would be produced were the
alloy here described so carefully fluxed and cast as to exceed
in strength the unfluxed alloys actually tested, 1,001 A, B, C,
D, in as great a proportion as 1,252 ^excels 1,252 A. The dia-
gram i ,00 1 y would be produced were it possible to so far
improve this alloy as to cause it to excel 1,252 A as greatly
as No. i ,00 1 actually did excel the gun-bronze made under
similar conditions in this preliminary rough work. No. 1,004
A is copied to exhibit the superiority of the alloy 1,001 to
one but little removed from it, and which is considered by
some brass founders an excellent composition.
255. The Tenacities of the Strong Alloys of copper, tin,
and zinc, as obtained by the investigation just described, are,
as has been seen, quite variable, and the result of the whole
has been fully confirmatory of Major Wade's conclusion rela-
tive to useful alloys of copper with softer metals : that they
are subject to great variation of quality, as ordinarily made,
and that it is impossible to predict with certainty the sound-
ness, the uniformity, and homogeneousness, or the strength
of any casting in bronze or brass. A study of the figures here
obtained, however, and of the map or model exhibiting them,
shows that, with good castings of any of the more valuable
compositions, certain methods of variation and a general law
may be formulated. Thus, for true bronzes containing usual
amounts of tin, the tenacity, as such castings are commonly
STRENGTH OF KALCHOWS.
431
43 2 MATERIALS OF ENGINEERING— NON-FERROUS METALS
made in the course of every-day business in the foundry, should
be about —
Te = 30,000 + 1,000 /;
where / is the percentage of tin, and not above 15 per cent.
Thus gun-bronze can be given about 30,000 4- (1,000 x 10)
= 40,000 pounds per square inch, if well made. In metric
measures
T* = 2,109 + 70-3 A
giving for good gun-metal 2,109 x 7°3 = 2,812 kilogs. per
sq. cm.
For brass (copper and zinc) the tenacity may be taken as
TM = 10,000 + 500 £,
where the zinc is not above 50 per cent.; and
7? = 2,109 + 35-15*
Thus copper 70, zinc 30, should have a strength of 30,000
4- (500 x 30) = 45,000 pounds per square inch, or 2,109 +
(35.15 x 30) = 3,165 kilogrammes per square centimetre.
Referring once more to Figures 24 and 25, it is seen that a
line of maximum elevation crosses the field marking the crest
of the mountain in Figure 25, of which the " maximum bronze "
is the peak. This line of valuable alloys may be practically
covered by the formula :
M - z + 3 t = Constant = 55,
in which z is the percentage of zinc, and t that of tin. Thus
a maximum is found at about t = a , z = 5 5, while the other
end of the line i*j z — o, t = 18.
STRENGTH OF KALCHOIDS. 433
Along this line the strength of any alloy should be at least
Tm = 40,000 + 500 z.
Tml = 2,812 + 35.15 3.
Thus the alloy z = i, t = 18 will also contain copper =s
IOO — 19 = 81, and this alloy Cu, 8 1 ; Zn, I ; Sn, 18, should
have a tenacity of at least
Tm = 40,000 + (500 x i) = 40,500 Ibs. per sq. in.
T*m = 2,812 + (35.15 x i) = 2,847 kilogs. per sq. cm.
The alloy Cu, 60; Zn, 5 ; Sn, 16, should have at least the
strength
Tm = 40,000 + (500 x 5) = 42,500 Ibs. per sq. in.
T*m = 2,812 + (35.15 x 5) = 2,988 kilogs. per sq. cm.
while the alloy Zn, 50 ; Sn, 2 ; Cu, 48, should give, as a mini,
mum per specification :
Tm = 40,000 + (500 x 50) = 65,000 Ibs. per sq. in.
Tlm = 2,812 + (35.15 x 50) = 4,570 kilogs. per sq. cm.
These are rough working formulas that, while often de-
parted from in fact, and while purely empirical, may prove of
some value in framing specifications. The formula for the
value of Tm fails with alloys containing less than I per cent, tin,
as the strength then rapidly falls to t — o.
The table which follows will present, in convenient form,
probably fair minimum values to be expected when good
foundry work can be relied upon, and may ordinarily be used
in specifications with the expectation that a good brass-founder
will be able to guarantee them.
28
434 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXVIII.
MINIMUM TENACITY OF ALLOYS.
ALLOY.
TENACITY.— Probable Minimum.
Cu.
Zn.
Sn.
Lbs. per sq. in.
Kgs. per sq. cm.
100
0
0
30,000
2,109
95
5
0
32,500
2,285
90
10
o
35,ooo
2,460
85
15
0
37>5oo
2,636
90
0
10
40,000
2,812
95
o
5
35,ooo
2,460
97*
0
2|
32,500
2,285
90
5
5
37,500
2,636
85
10
5
40,000
2,8l2
75
20
5
45,ooo
3,163
68
30
2
47,000
3,304
64
35
I
48,500
3.410
60
40
0
50,000
3,515
256. Ductility. — The ductility of these alloys is a subject
of as much interest to the engineer as their strength ; and in
this quality the ternary alloys are as variable as in every other.
Referring again to the map, Figure 27, it is seen that a
closely grouped set of slightly curved and slowly converging
lines cross it from tin — 25, to zinc = 55, the mean line having
an equation nearly 2.2/ + z — 55. Along this line the alloys
have immense tenacity, as exhibited by the fact that some of
them, if not nearly all, are too hard to be cut by steel tools,
and in shaping them only grinding tools — either the emery
wheel or the grindstone — could be used, and even then with
most unsatisfactory results. Yet such was the brittleness of
these metals that no reliable test of their strength could be
obtained. The strain-diagrams obtained were straight, and
nearly vertical lines, terminating suddenly, when the piece
snapped, without indication of approach to an elastic limit.
They were perfectly elastic up to the point of fracture, but
were so destitute of resilience that no use can probably be
made of them by the engineer. Their brittleness was such
that they would often break in the mould by contraction in
STRENGTH OF KALCHOIDS.
435
cooling, although cast in a straight bar. In some cases they
crack by the heat of the hand, and were broken at one end
by the jar transmitted from a light blow struck at the other
end.* The border line of this valueless territory is shown
• FIG. 27. — TENACITY OF COPPER-TIN-ZINC ALLOYS.
on the map by a slightly curved dotted line to which a line
having the equation 2.5* -f s— 55 is nearly tangent. The
alloys lying along this line have nearly equal ductility, ex-
tending, according to measurements obtained by the auto-
graphic machine, about .03 of one per cent.
* Report to U. S. Board. Figure from the R.R. Gazette.
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Above this line is another having nearly the equation
4/ + s = 50, which last line is that of equal ductility for alloys
exhibiting extensions of 3 per cent. Still nearer the " pure
copper corner" is a line fairly representing alloys containing
about y>/^t + z — 48, and along which the extensions were 7.3
per cent., and another such line extending from standard gun-
metal compositions on the one side to Muntz metal on the
other — Cu 90, Sn 10, to Cu 55, Zn 45, — of which the equa-
tion is nearly 4.5^ + z — 45, represents alloys averaging an
extension of 17 per cent. These lines are best seen on the
sheet of extensions, Fig. 28. All alloys lying above the line
taken here as a boundary line give figures for tenacity that ex-
ceed 30,000 pounds per square inch (2,109 kilogs. per sq. cm.).
The addition of tin and of zinc to cast copper thus in-
creases tenacity at least up to a limit marked by the line
3/ + z— 55 ; but the influence of tin is nearly twice as great
as that of zinc, and the limit of useful effect is not reached in
the latter case until the amount added becomes very much
greater than with the former class — the copper-tin alloys.
Brasses can be obtained which are stronger than any bronzes,
and the ductility of the working compositions of the former
class generally greatly exceeds that of the latter. Ternary
alloys may be made containing about 4^ + z = 50, which ex-
ceed in strength any of the binary alloys, and compositions
approaching copper, 55; tin, 2; zinc, 43; may be made, of
extraordinary value for purposes demanding great strength,
combined with the peculiar advantages offered by brass or
bronze. The addition of one-half per cent, tin to Muntz
metal confers vastly increased strength.
The range of useful introduction of tin is thus very much
more restricted than that of zinc; alloys containing 12 to 15
per cent, tin are so hard and brittle as to but rarely find ap-
plication in the arts, while brass containing 40 per cent, zinc,
is the toughest and most generally useful of all the copper
zinc " mixtures." The moduli of elasticity of these alloys are
remarkably uniform, more than one-half of all those here
described ranging closely up to fourteen millions, or one-half
that of well-made steel-wire. The moduli gradually and
STRENGTH OF KALCHOIDS. 437
slowly increase from the beginning of the test to the elastic
limit.
The Fracture of these Alloys is always illustrative of their
special characteristics. Those broken by torsion in the
autographic testing machine were, if brittle, all more or
less conoidal at the break ; ductile alloys yield by shearing in
a plane at right angles to the axis of the test piece ; the for-
mer resemble cast iron and the latter have the fracture of
wrought iron. Every shade of gradation in this respect is
exhibited by an observable modification of the surface of
fracture varying from that characteristic of extreme rigidity
and brittleness, through an interesting variety of intermediate
and compound forms to that seen in fracture of the most
ductile metals.
257. Possibilities of Improvement. — The tenacities and
ductilities given are within the best attainable figures where
they relate to the most valuable working bronzes and brasses.
These figures represent the result of ordinary founders* work ;
and metals rich in copper, made with no greater precaution
against oxidation and liquation than is usual in brass foun-
dries, may be vastly improved by special treatment sug-
gested, by using pure ingot metals, fluxing carefully, as
with phosphorus or manganese, casting in chills, rapid cool-
ing, and finally rolling, or otherwise compressing, either hot or
cold.
Unannealed copper wire is reported by Baudrimont* as
having a tenacity of about 45,000 pounds per square inch
(3,163 kilogs. per sq» cm.), and Kirkaldy reports 28.2 tons per
square inch (63,168 pounds per square inch, 4,440 kilogs.
per square cm.), the wires having diameters of 0.0177 and
0.064 inches (0.044 and 0.165 cm.) respectively.
A way should be found to secure equal purity, homo-
geneousness, and density in cast copper, and such metal
should then possess tenacity and toughness equal to that of
rolled metal. Gun-bronze, which ordinarily has a tenacity of
about 35,000 pounds per square inch (2,460 kilogs. per sq.
cm.) has been made at the Washington Navy Yard, by skil-
* Annales de Chimie, 1850.
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
ful mixture, melting and pouring, and by the Author, also, to
attain a tenacity of above 60,000 pounds (4,218 kilogs.).
The effect of thorough fluxing with deoxidizing sub-
stances is so important that no founder can safely neglect it*
FIG 28.
DUCTILITY OF COPPER-TIN-ZINC ALLOYS.
60 COPPERE
Bronzes fluxed with phosphorus, arsenic, and manganese,
have been given fifty per cent, higher tenacity than the or-
dinary unfluxed alloy, and the addition of a little iron, as in
the so-called " sterro-metal " of the Baron de Rosthorn, and
in Parson's " Manganese Bronze," has still further strengthened
the copper-tin-zinc alloys.
Dr. Anderson made experiments at Woolwich, showing
STRENGTH OF KALCHOIDS. 439
an increase of strength of sterro-metal, by forging, to the
extent of 25 per cent., and by drawing cold of 40 per cent.
Brass, containing copper, 62 to 70, zinc, 38 to 30, attains a
strength in the wire mill of 90,000 pounds per square inch, and
sometimes of 100,000 (6,327 to 7,030 kilogs. per sq. cm.), and
these alloys should be made equally tenacious in the casting.
The Author has no doubt that the methods indicated as those
best adapted to secure dense, strong and tough metal will
yet be found capable of yielding alloys of more than double
the strength representative of what is now ordinary brass-
founders' work. It should be possible to secure copper-tin-
zinc alloys having tenacities represented by :
Twm — 60,000 + irooo/ + 500 z,
70.3* + 35-i5*f
throughout that area on the map representing the most use-
ful alloys, from copper, 100, to 4^ + z = 50.
Manufacturers of special bronzes are approaching this de-
gree of excellence.
In the working of copper in the foundry the melter meets
with difficulty from the formation of either the oxide or car-
bide. Could he secure immunity from combination with one
or the other of these elements, he would find innumerable
uses for cast copper.
The general character and the method of variation of
strength and ductility of the alloys of copper, tih, and zinc
are so well exhibited by the illustrations presented, that no
difficulty will be met with by the engineer in the endeavor to
select the alloy best adapted to any specific purpose where
such an adaptation is determined by physical qualities alone.
Caution must be used in selecting alloys where great strength
is demanded, since a slight change of composition by the ad-
dition of tin or zinc may make a serious change in the direc-
tion of lessened ductility and toughness. The engineer will
rarely use those lying on the tin and zinc side of the line of
alloys having 0.07 (7 per cent.) ductility, as on Figs. 27 and 28.
Extraordinary care must be taken in making the strongest alloys.
44° MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Alloys to be hammered or rolled will be found more diffi-
cult to work as the percentage of tin is increased, and the
minutest addition of tin to the brasses usually rolled is found
to sensibly decrease their manageability.
258. The " Maximum Bronzes" form a group demand-
ing special consideration as including a collection of generally
unfamiliar but exceptionally valuable alloys.
The work planned by the Author in the investigation of this
part of the subject was left incomplete by the U. S. Board, but
was continued, as opportunity offered, at intervals up to the
year 1884.* The position and characteristics of the strongest
possible alloys of the three metals constituting the "Kalchoids"
having been determined with a fair degree of accuracy, as al-
ready described, the next step was to ascertain what modifi-
cations might be produced in them by careful fluxing and the
use of still more carefully prepared alloys. This later study
was made in the years 1882-3, in the same manner as the
earlier investigations for the U. S. Government, at the sug-
gestion and under the supervision of the Author, by Mr. W.
E. H. Jobbins, whose report is here abridged. f
The area chosen as the field of this investigation was a
small triangular portion surrounding the peak of the moun-
tain, Fig. 25, marked 65,000 on Fig. 24, as this area embraces
all that portion of the field in which the most valuable alloys
had been proven to be located. The data obtained gave ex-
ceedingly high figures, the lowest average value of tenacity
being above 50,000 pounds per square inch (3,515 kilogs. per
sq. cm.)- As this research extended over a very limited area,
it was possible to conduct the investigation with much greater
exactness than before, and thus settle the composition of the
" strongest of the bronzes."
The metals varied with differences of but one per cent.;
23 combinations were chosen ; 2 test-pieces were made of each
* The U. S. Board was strangled by refusal of appropriations, leaving the
work in hand unfinished. Some of the work necessary to the presentation of the
reports actually made was, however, concluded by the Author, at some expense^
in the Mechanical Laboratory of the Stevens Institute of Technology.
f " Investigation Locating the Strongest of the Bronzes," J. F. I., 1884.
STRENGTH OF KALCHOIDS.
441
composition, making 46 test-pieces. Usually, the data obtained
from two specimens of the same composition agreed so closely
that the average value was safely taken ; but, when there was
a marked difference, the data agreeing more closely with the
results anticipated from analogy were adopted, and the other
value rejected as being probably erroneous. The copper em-
ployed was from Lake Superior, the zinc from Bergen Port.
In the use of tin, phosphorus was added to give soundness
in these copper-tin and copper-tin-zinc alloys, which are so
liable to be made seriously defective by the absorption of oxy-
gen and the formation of oxide. It has been found possible to
produce, on a commercial scale, an alloy of phosphorus and
tin, which, while containing a maximum percentage, does not
lose phosphorus when remelted. The best proportions for
practical purposes are said to be tin 95 per cent, and phos-
phorus 5 per cent.
After careful study, the following limits of the field were
decided upon: Copper, maximum 60, minimum 50; Zn, 48
and 38 ; Sn, 5 and o. These limits include the best alloys for
purposes demanding toughness as well as strength.
The compositions are given in the following table :
TABLE LXXIX.
BEST COPPER-TIN-ZINC ALLOYS, OR KALCHOIDS.
NO.
cu.
ZN.
SN.
NO.
cu.
ZN.
SN.
NO.
CU.
ZN.
SN.
I
55
43
2
9
53
43
4
17
58
40
2
2
54
44
2
10
55
4i
4
18
54
45
I
3
54
43
3
II
57
4i
2
T9
53
44
3
4
55
42
3
12
57
43
0
20
54
42
4
5
56
42
2
13
55
45
O
21
5<>
41
3
6
56
43
I
14
52
46
2
22
57
42
i
7
55
44
I
15
52
43
5
23
58
4i
i
8
53
45
2
16
55
40
5
The castings were made much as in all the earlier investi-
gations, the same precaution being taken to prevent volatili-
zation of zinc, and care was taken to secure rapid cooling to
prevent liquation. All the compositions thus made were
442 MATERIALS OF ENGINEERING— NON-FERROUS METALS
strong and usually tough ; all could be turned and worked
safely, and all were evidently of commercial value for the pur-
poses of the engineer. All test-pieces were sound, and even
microscopic examination revealed no defects in structure.
The investigation was made by the use of the Author's auto-
graphic machine as permitting most rapid work and most ex-
act determinations of quality and behavior, especially as to
the latter near the elastic limit. The samples were all re-
duced to the standard form and size.
259. Results of Tests. — The formula used is M = wh +
/; where w — moment necessary to deflect the pencil one
inch ; h — height of the curve above the base line at 0r, / —
friction in foot-pounds, and M is the total torsional moment.
In this case, w = 96.93 foot-pounds, and/"= 4«75> ^ being
measured on the strain-diagram of each test-piece. To obtain
the required values of T the formula T= [300— j^0J M,* in
which M is known, and 6r is measured directly from the
autographic record ; T is the calculated tenacity. The
values of M, T, 6e and #„ the total moment, the approximate
tenacity, and the angles of torsion at the elastic limit and at
rupture, have been included in the following table :
TABLE LXXX.
STRENGTH OF BEST COPPER-TIN-ZINC ALLOYS OR KALCHOIDS.
ORIGINAL
STRESS IN TORSION.
FOOT-POUNDS.
M.
APPROXIMATE
STRESS IN TENSION.
FOOT-POUNDS.
r
ANGLES.
MARK.
Ultimate.
Average.
Ultimate.
Average.
9.
Qr
IXI A
270.208
251.922
261.065
77,309
72,301
74,305
i-5°
i
43°
40
OB A
178.321
208 . 400
193.369
53,946
59,810
56,653
i.i
0.7
5-05
40
'3 i
251.922
219 935
235-929
75,57^
65,980
70,778
i
i
13.77
10
J4 $
24^.392
258.319
250.851
73,oi7
74,9"
73,965
2
2
19.8
30.3
* This relation between torsional and tensional resistances was obtained by
experiment on the machine used in this investigation. Trans. Am. Soc. C. E.,
no. clxiii., vol. vii., 1878.
STRENGTH OF KALCHOIDS.
TABLE LXXX.— Continued.
443
ORIGINAL
MARK.
STRESS IN TORSION.
FOOT-POUNDS.
M.
APPROXIMATE
STRESS IN TENSION.
LBS. PER SQ. IN.
T.
ANGLES.
Ultimate.
Average.
Ultimate.
Average.
Qe
$r
Ft A
Fs B
268.881
263.543
266.212
75,824
75,109
75,467
4.6°
2
55°
46
r h A
G6 B
227.689
' 220.612
224.151
64,208
63,193
63,700
2.O5
2
53.3
42.1
K7 A
286.847
250-855
268.851
80,910
70,741
75,826
2
2
54
53
R8 A
194.634
184.331
189.488
58,390
55,299
56,844
2
2.69
9.1
5-72
*><) B
222.853
230.597
226.725
66,853
69,179
68,017
1-5
1.79
5-78
4-5
Lio A
249.014
252.881
250.948
74,704
75,864
75,284
2.1
2.8
4.6
8.8
Zn A
260.645
237.382
249.014
74,269
63,964
69,116
2.4
1.9
39-8
35
DB A
227.689
241-259
234-474
61,020
61,762
61,390
2-3
1.6
95-2
I3I-4
Mi3 B
227.689
208 . 303
217.996
64,208
57,908
61,058
2
I.I
52.4
65
Ui4 £
163.715
I77-I85
170.450
49,H3
53,155
51,139
2-3
2
4.9
7-2
V'5 i
189.886
227.689
208.788
56,965
68,306
62,636
2.6
2
4
5
Ni6 *
225.750
253-198
239-974
67,725
75,959
71,842
.6
.6
3.8
6.8
A 17 £
227.689
250.952
238.771
63,200
73,488
68,344
•4
.8
54
43-2
Pig A
254-829
260.645
259-737
72,871
7i,50i
72,186
.6
.8
43-4
54
T.9 £
231. 566
196.671
214. 119
69,459
59,001
64,230
.2
•4
8
4.8
QBO A
229.628
258.707
244.168
68,888
77,612
73,250
.6
.8
6.4
7-2
HBI A
283.908
229 628
266.768
81,381
68,888
75,135
2.9
2.4
38
8
EBB g
305-233
221.773
263 . 508
85,770
60,986
73,378
2
2-5
56
76
B33 £
225.750
175.247
200 . 499
63,084
45,038
54,061
I 6
1.2
63
128
The neck subjected to distortion is in all cases, one inch
(2.54 cm.) long between shoulders and ^ inch (1.5875 cm.) in
diameter.
260. Discussion. — It proved, notwithstanding the pre-
444 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
cautions taken in making these alloys, to be a matter of some
difficulty to decide satisfactorily the relative positions of the
alloys studied. Nos. 7 and 22 were the best alloys made.
No. 7 was a fine grained alloy, with a smooth, even fract«
ure, tough fibrous appearance, and twisted apart slowly and
evenly. No. 22 was an alloy, golden in color, very close
grained and with a fracture in all re'spects similar to No. 7,
and exceedingly tough. It was found that, when the average
values of J/and T were used, No. 7 stood first upon the list,
while, when the higher values were taken, No. 22 was first.
In the case of No. 22 there was a difference in the values
which indicated a change in composition either from volatili-
zation or from some other cause. No. 22 must be considered
the strongest alloy.
The third upon the list is No. 21. It exhibited con-
siderable liquation. The metal was of a bright straw color
and had a smooth, regular fracture and considerable ductility.
No. 5 was fourth and No. I fifth. No. 5 was a very fine-
grained alloy, possessing great ductility and a smooth, square
fracture and very close and compact grain. Higher results
can undoubtedly be obtained from an alloy of this composi-
tion ; these specimens showed signs of slight liquation.
No. I was a tough metal, the pieces being twisted apart
slowly, snapping suddenly, as in the previous case ; better
results should be expected from this alloy ; it exhibited signs
of an imperfect mixture of the metals. This was the strongest
alloy reported by the Author previously. The sixth position
was assigned to No. II, which exhibited a fine regular fract-
ure and high ductility ; it twisted apart slowly and evenly.
No. 1 8 was a good alloy, and although more crystalline than
those previously mentioned, had a smooth fracture and high
moduli ; it was very ductile. The eighth upon the list, No. 10,
was a very brittle alloy ; its values for #,. being but 4.6° and
8.8° ; its color was gray, with a fracture closely resembling
steel. Its tenacity was 75,000 pounds per square inch (5,272
kilogs. per sq. cm.), a higher figure than some of the preced-
ing alloys have given ; it was very hard. No. 4 stands ninth.
There was considerable liquation ; while it exhibited a smooth
STRENGTH OF KALCHOIDS. 445
and regular fracture and broke off slowly and evenly. It
was light yellow in color. Its upper end was granular and
uneven in fracture ; it was of a very light gray color, indi-
cating a brittle metal, but it was quite strong and ductile.
This alloy contained i per cent, more zinc and i per cent,
less tin than No. 10, and, though having slightly less strength,
it was far more ductile. The next best alloy, No. 20, an alloy
very bright in color, almost white, and having a ragged fract-
ure, was an exceedingly brittle alloy, its average value for
6r being but 6.8° ; its tenacity was very good. The eleventh,
No. 1 6, was a remarkably dense alloy, very hard, with a fract-
ure closely resembling steel. Its strength was very great.
No. 3, the twelfth on the list, was less brittle than the pre-
ceding, its average value of 6r being 1 1.9°. While testing the
A end a " set " took place. It broke suddenly, giving a very
ragged, granular fracture ; it was light in color. Thirteenth,
No. 17, was a very ductile alloy, its values for Br averaging
48.6°. It was of a deep golden color, and had a smooth,
regular fracture. Fourteenth, No. 19, was close-grained,
brittle, nearly white in color, and gave a very ragged and
uneven fracture ; it broke suddenly. Fifteenth, No. 9, was
another very brittle alloy, with a fracture closely resembling
steel. Sixteenth, No. 6, was very ductile, giving a smooth,
regular fracture. Its values of tenacity were good. Seven-
teenth, No. 12, was not a triple alloy, as it contained copper
and zinc only. It was an exceedingly beautiful alloy, of a
deep golden color and very closely grained. This was, by
far, the most ductile alloy tested, the average of Br being
113.3°. Eighteenth, No. 23, was the second most ductile
alloy. This alloy had a fine fracture, smooth and regular.
In color, it very closely resembled green bronze. Nineteenth,
No. 13, was also a binary alloy, and though resembling No.
12 in appearance its ductility was only about one-half that
of No. 12. Twentieth, No. 15, was exceedingly brittle, and
closely resembled steel in fracture. Twenty-first, No. 2,
was surrounded by alloys which gave much better results,
and therefore a weak specimen ; this was not looked for in
this place. It was ductile and had a good, even fracture ; it
44-6 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
resembled No. 23 in color. Twenty-second and twenty-
third, Nos. 8 and 14, both contained large amounts of zinc
and little copper, and consequently were both brittle and
weak.
FIG. 29. — STRONGEST OF BRONZES.
261. Conclusions. The Strongest Bronzes. — The results
obtained from this investigation are well exhibited in the ac-
panying diagram, Fig. 29. It was concluded that the alloy
numbered 22 was what the Author has called the " strongest
of the bronzes," and that its composition (Cu, 57; Sn, I ; Zn,
42) should locate the peak seen in the model, Fig. 25, and on
the map, Fig. 24. No. 5, however (Cu, 56 ; Sn, 2 ; Zn, 42),
is likely to prove a more generally useful alloy in consequence
STRENGTH OF KALCHOIDS. 447
of its greater ductility and resilience ; and alloys with a little
less tin may often prove even better than that. The Author
has called the compositions, copper, 58 to 54; tin, y2 to 2j£;
zinc, 44 to 40, which may be considered as representative of
a group having peculiar value to the engineer, the "maximum
bronzes" This cluster lies immediately around the peak seen
on the model, Fig. 25, including the point of maximum alti-
tude. The safest alloys under shock are those containing
the smallest quantities of tin.
262. The Conclusions reached after concluding the in-
vestigations which have been described in the present chap-
ter are confirmed by the fact that a number of single compo-
sitions have been independently discovered by other experi-
menters, accidentally or incidentally to special investigations,
which have peculiarly high tenacity, all of which approximate
more or less closely, in their proportions, to these " maximum "
bronzes and strongest " Kalchoids."
Thus, Mr. Farquharson, president of the Naval (British)
Commission, proposed, in 1874, an alloy composed of 62 parts
of copper, 37 parts of zinc, and one part of tin. This is the
reglementary naval alloy. When cast in bars it has shown
on test a resistance of 70,000 pounds per square inch (5,000
kilogs. per sq. cm.). It rolls and works well, can be hammered
into sheets, and is fusible only above red heat. It may be
used as a lining for engine-pumps. It is but slightly oxidiz-
able, and is not sensibly attacked by sea water, as shown by
experiments with it extending over a period of years. A slight
loss of zinc during melting must be taken into account. The
British naval bronze for screw-propellers, stern bearings, bow-
castings, and similar work, is composed of copper, 87.65 ; tin,
8.32 ; zinc, 4.03, and is reported to have a tenacity of 15 tons
per square inch (2,362 kilogs. per sq. cm.), and to average
13^ tons (2,126 kilogs.) in good castings. Tobin's alloy, al-
ready described, is one of the " maximum " bronzes, also,
containing copper, 58.22 ; tin, 2.30; zinc, 39.48. Sterro-metal
is always a brass of nearly the same proportions of copper and
zinc, i.e., a Muntz metal, containing from a fraction of I per
cent, to sometimes 2 per cent, of tin, as well as some iron.
448 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The bronze used for journal bearings in the U. S. Navy
contains copper, 88; tin, 10; zinc, 2.* The strongest U. S.
copper-tin-zinc alloy is that discovered by Mr. Tobin and
described by the Author in earlier articles, and, as has been
stated, had a tenacity of 66,500 pounds per square inch of origi-
nal section, and 71, 378 per square inch of fractured area(4,575
and 5,019 kilogrammes per sq. cm.) at one end of the bar, which
was, as usual, cast on end, and 2 per cent, more at the other.
This, like the " maximum alloy," was capable of being forged
or rolled at a low red heat or worked cold. Rolled hot, its
tenacity was 79,000 pounds (5,553 kilogs. per sq. cm.), and
when cold-rolled, 104,000 (7,311 kilogs.). It could be bent
double either hot or cold, and was found to make excellent
bolts and nuts.
These and other compositions which have been occasion-
ally introduced as having extraordinary strength and excep-
tional value, all contain a small amount of tin, and invariably
fall within the field mapped out as described in this chapter
as that containing the kalchoids of maximum possible strength.
The latter, the ** maximum alloys," as the Author has called
them, will probably be very generally, if not exclusively, used
when alloys are required of peculiar strength.
* This kalchoid composition has been prescribed by the U. S. Ordnance
Bureau for gun-carriages and also Cu 55, Zn 44.5, Sn 0.5 ; the latter having a
mean tenacity of 50,000 to 60,000 and a maximum of 64,000 pounds per square
inch. — Reports, 1898.
CHAPTER XII.
STRENGTH OF ZINC-TIN AND OTHER ALLOYS.
263. The Zinc-Tin Alloys form the third bounding line
of the system of copper-tin-zinc alloys which have been stud-
ied, as the copper-tin and copper-zinc compounds form the
two sides first examined. Within the field represented on
the map, Art. 252, page 425, and on the tin-zinc side of the
depression which lies parallel with the crest of maximum
strength, are also a set of ternary alloys characteristically
different from those which have been the object of specia.
investigation. These are the gray and the white alloys of
copper, tin, and zinc, which have no use .in the work of the
engineer except for bearing metals and as solders. The char-
acteristics and uses of these alloys are so similar to those of the
tin-zinc alloys that they are here classed and treated of together.
The zinc-tin alloys are usually easily made, and are sound
and dense and uniform in quality and structure. They are
soft, weak, smooth of texture, as a rule, and readily alloy with
the surface coating of tin-plate and with zinc; they thus make
good "soft solders" as well as good metals with which to line
the bearings of heavy journals in heavy machinery. Common
solders are elsewhere described. Among them are " yellow
solder," composed of equal percentages of copper and zinc,
with one part tin either added or substituted for two or three
per cent, zinc ; " black solder," composed of 30 copper, 45
zinc, and tin, 25 ; these fall among the stronger alloys out-
side the gray mixtures.
No tests of the tin-zinc alloys were made in the research
described in the preceding chapter, but the study of the
model, Fig. 25, page 427, gives the value of this set of com-
pounds as satisfactorily as if they had all been directly inves-
tigated.
29
45O MATERIALS OF ENGINEERING— Nv^-^ERROUS METALS.
264. The Strength of Tin-Zinc Alloys is seen to vary
very smoothly and uniformly from the pure zinc to the pure
tin end of the series. It may, therefore, be assumed as sub-
stantially true that the strength of the tin-zinc alloys is the
mean of that of their constituents. This is also practically
true of their other physical and mechanical properties. Hence,
the tenacity of good alloys of this class should be expected to
be not far from
T= 4,500 t + 7*000.?,) ,~
7*.. = 316* + 492*, }
in British and metric measures, respectively, where / and z
represent the proportion of each metal in unity of weight.
The Resistance to Compression is, for tin-zinc alloys, fairly
taken as below, for ten per cent, compression,
C = 6,000 t + 20,000 Z,\ , .
Cm = 422 / + 1,406 *, ]
The Modulus of Rupture maybe taken for tin-zinc com-
positions, at
R-= 3,500^ + 7»5oo*,)
Rm = 246 t + 527 *, }
and the Modulus of Elasticity at 7,000,000 British, 492,000
metric for all. The Specific Gravity is fairly reckoned at
S.G. = 7.3^ + 7.15* (19)
265. The Gray Alloys of copper, tin, and zinc are more
uniformly modified by the addition of copper to the tin-zinc
compounds than are the yellow and stronger alloys. Those
containing little zinc are very irregular in strength, but, on
the whole, weaker than those containing little tin, and are
generally but little stronger than the latter metal. These cop-
per-tin-zinc alloys, rich in zinc and poor in tin, are strongest
where the compositions contain between copper, 15 or 20,
zinc, 85 or 80, and are weakened quite uniformly by the ad-
dition of tin, and by either the increase or diminution of the
STRENGTH OF ZINC-TIN ALLOYS. 45 1
proportion of zinc, the tensile strength becoming insignificant
when the proportions are such that, approximately,
2 + 2 t = 90 per cent.,
along which line lie the alloys of maximum hardness and
brittleness.
The tenacity of this group of alloys usually ranges be-
tween 3,000 and 5,000 pounds per square inch, sometimes
reaching 10,000(211, 351, 703 kilogs. persq. cm., respectively);
the resistance to compression is not known ; the modulus of
rupture falls, usually, not far from 5,000 pounds per square
inch, rising to above 10,000 (352 and 703 kilogs. per sq. cm.),
and as often falling below the smaller figure. The modulus
of elasticity is generally about 12,000,000 (844,000 metric),
although with the softer alloys it falls to one-half that amount.
266. Earlier Investigations of these alloys have been of
little value in determining their properties. An alloy of tin,
80 ; zinc, 20, is said, by earlier writers, to have a tenacity of
10,000 pounds per square inch (703 kilogs. per sq. cm.), or
double that estimated as above. The alloy, zinc, 77; tin, 14;
copper, 14; antimony, 3; lead, I, which falls into the class
here considered, very nearly, is Burton's alloy for plough-
shares. Magee's, for the same purpose, is copper, 85 ; tin, 12;
zinc, 3. Zinc, 20 ; tin, 20, is Brayton's alloy for eyelets. Stru-
bing's anti-friction metal is composed of zinc, 75 ; tin, 18;
lead, 4>2 ; antimony, 2}£. The alloy composed of equal parts
tin and zinc is said by Laboulaye to be remarkably durable
under wear, and to have nearly the strength of brass, a state-
ment which is not confirmed by the investigations here de-
scribed and requires confirmation. The strength of many of
these alloys has never been determined.
An " anti-friction metal," of unknown composition, tested
by the Author, had a tenacity of 11,100 pounds per square
inch (773 kilogs. per sq. cm.), and broke without stretching.
An alloy of gold, 14 ; silver, 10, with a trace of copper, is
often made into wire to replace brass, and is found to have
about the same strength.
45 2 MA TEs TALS OF ENGINEERING— NON-FERROUS METALS.
Variou* alloys examined by Muschenbroek,* who was the
only phyp'^ist, or engineer, who had given much time to the
study of the mechanical properties of alloys until a very
recent period, were found to have tenacities as given in the
following table to the nearest thousand.
TABLE LXXXI.
TENACITY AND DENSITY OF VARIOUS ALLOYS.
TENACITY.
ALLOYS.
Lbs. per
Kilogs. per
S. G.
sq. in.
sq. cm.
old, 66.7; Silver, 33.3
28,000
1,968
83.3; Copper, 16.7....
50,000
3,515
.
ilver, 83.3; " 16.7. ...
49,000
3>445
%
" 80.0; Tin, 20.0
41,000
2,882
t
in (Eng.), 90.9; Lead, 9.1
7,000
492
.
4
88.9; II. i
8,000
562
.
'
85-7; I4-3-.-.
8,000
562
§
i
80.0; 20. o. . . .
11,000
773
.
4
66.7; 33.3
7,000
492
.
'
50.0; 50.0
7.000
492
.
n (Ba
nca), 90.9; Antimony, 9.1... .
11,000
773
7-36
88.9;
ii. i. . . .
10,000
703
7.28
85.7;
14.3....
13*000
914
7-23
80.0;
20. o. . . .
13,000
914
7.19
66.7;
33-3....
12,000
874
7.II
50.0;
50.0
3,000
211
7.06
n(Ba
nca), 90.9; Bism
uth, 9. i. ...
13,000
914
7.58
80.0;
20.0
8,000
562
7.6l
66 7;
33-o....
14,000
984
8.08
50-o;
50.0
12,000
844
8.15
33.3;
66.7....
lO.OOO
703
8.58
20 o;
80 o
8,000
562
9.0*1
Q.I;
90.9 —
4,000
281
9.44
, ad, 50.0; Bisrr
uth, 50.0
7,000
492
10.93
66.7;
33-3-...
6,000
422
11.09
9.1;
90.9....
3,000
211
10.83
267. The Records of Experiments upon the copper-tin-
zinc alloys which follow are selected from those reported by
the Author to the Committee on Alloys of the U. S. Board
as representative of the more successful mixtures. These
alloys have been already described at some length, and further
* Introd. ad Phil. Nat.; Phil. Ma^., 1817, Vol. L.; Tredgold.
STKENG TH OF COPPER-ZINC- TIN ALLO VS. 45 3
description in detail is here unnecessary.* Although selected
examples, some considerable part of the variation observed
among them is probably due to the varying conditions met
with in ordinary foundry work ; the principal cause of these
great differences of strength and ductility is, however, to be
attributed to differences in composition. It will be observed
that the strongest of these alloys are not distinguished by
great ductility, a fact already frequently illustrated in earlier
portions of this work.
Examining the records of test by tension, it is seen that
the better class of alloys exhibit a great regularity of elonga-
tion under increasing loads. Comparing the tenacities of the
best specimens with the moduli of rupture, it is seen that the
latter exceed the former by about fifty per cent. In ductile
metals the resistances to compression and to extension do
not greatly differ where, as in a bent bar of the proportions
here adopted, the compressed metal is not confined. The
modulus of rupture for a beam of rectangular section when
the material is elastic and brittle is that given in the common
theory of resistance of materials, R = -7-=—, in which M, &, dy
ba2
are the bending moment, the breadth and the depth of the
bar. When the material is ductile, R, — —=-, and, there-
bd2
fore, R = | ^ when the bar is of the same dimensions and
the same bending moment is attained at rupture, assuming
the same theory applied to each case and the apparent mod-
ulus to be accepted.f
In the cases of some of the valuable alloys of which the
records of test are here given, the moduli of rupture are often
in excess of the tenacities by fifty per cent., or in the same
proportion as in wrought iron4 proving them to belong to the
class to which the second of the expressions just given be-
longs. This is best illustrated by bar No. 12 (copper, 58.22 ;
tin, 2.30; zinc, 39.48).
* Vide Report of the U. S. Board, Vol. II., Washington, 1881.
f Part II., p. 487, § 263, Eq. (113).
\ Part II., p. 491.
454 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
TABLE LXXXII.
TESTS BY TENSILE STRESS.
ALLOYS OF COPPER, TIN, AND ZINC.
DIMENSIONS. — Length = 5" (12.7 cm.); diameter = .798" (2 cm.)t
BAR NO. I B-D.
COMPOSITION.— Original mixture: Cu, 70; Sn, 8.75; Zn, 20.25.
g
It
M
M
BE
w X
pj {J
I
SET.
*\
Ij
i
SET.
sf
§
PS
£5
<;
5»
Q
2
O E-*
Q
o
2 f-
3
3
M
P
3
i
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
1,400
.0031
.002
16,000
.0046
.092
i, 600
.OOOI
.002
18,000
.0052
.104
i, 800
.0002
.004
2O,COO
.0061
.122
2,000
.OOO2
. . .
.004
3 °
000
.002
2,500
.0003
. . .
.006
10,000
.0010
.020
3,000
.0004
. . .
.008
20,000
.0053
...
.106
3,500
0005
..
.010
22,000
.0064
.128
4,000
.0007
.
.014
24,000
.0084
.168
5,ooo
.0009
. ..
.018
28,000
.0142
.284
6,000
7,000
8,000
.OOI2
.0014
,OOl6
'• '•
.024
.028
.032
32,000
36,000
Broke.
.0217
.0316
'.'.'.
• 434
.632
9,000
10,000
11,000
12,000
13,000
.0022
.0024
.0028
.0031
0035
'• '•
.044
.048
.056
.062
.070
Tenacity per square inch, original section,
36,000 pounds (2,531 kilogs. per sq. cm.).
Tenacity per square inch, fractured section,
36,080 pounds (2,536 kilogs. per sq. cm.).
Diameter of fractured section, 0.797" (2 cm.).
14,000
.0038
. ..
.076
BAR NO. 5 B-D.
COMPOSITION.— Original mixture: Cu, 88.135 ; Sn, 1.865 ; Zn, 10.
3,200
.0014
•035
7,000
.0040
.100
4,000
.0018
•045
8,000
.0042
... .
.105
4,500
.0020
.....
.050
9,000
.0044
... .
.110
5,000
.0023
.057
10,000
.0050
... .
.125
5,5oo
.OO26
.....
.065
11,000
.0054
•
• *3S
6,000
.0028
.070
12,000
.0058
... .
.145
7,000
•0033
.....
.082
13,000
.0088
.220
8,000
.0036
....
.090
14.000
.0121
... .
.302
9,000
.0039
....
.097
15,000
.Ol6l
.402
10,000
.0043
.107
16,000
.0252
.630
11,000
.0047
....
.117
18,000
.0548
... .
1-370
12,000
.0052
....
.130
20.000
.0987
2.460
300
. ...
.COOS
22,000
• 1595
... .
3.987
IOO
.0011
.027
26,000
• 3»8
....
7-795
1,400
.0013
.032
30,000
• 5177
... .
12.942
1, 800
.0015
•037
33,000
.7818
19-545
2,200
.0017
.....
.042
Broke.
2,600
3,000
4,000
5,300
6,000
.0019
.0022
.0028
.0033
.0037
... .
•047
•055
.070
.082
.092
Tenacity per square inch, original section,
33,000 pounds (21.30 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
47,649 pounds (33.52 kgs. per sq. cm.).
Diameter of fractured section, 0.664" (J-7 cm.).
STRENGTH OF COPPER-ZINC-TIN ALLOYS.
455
TABLE LXXXIL— Continued.
BAR NO. 7 B-D.
COMPOSITION.— Original mixture: Cu, 66.885 ; Sn, 1.865 ; Zn, 31.25.
M
2 &•
M
Z b
K
~ O
«- O
j§
D
§
% •
55
2 £"*
O*
z
§^
X
O
*g
II
SET.
H LJ "^
K u
p
SET.
~ w a
a x
PH «
a
1
< h;
* "1
£5
Q
igS
§
s
M
M
O
•3
M
°ss
M
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
300
6,000
.0029
.058
1,000
.0002
.....
.004
8,000
.0033
t
.066
2,000
.0004
.008
10,000
.6042
.084
3,000
.0006
.012
12,000
• 0055
,
.110
4,000
.0008
.016
14,000
.0069
.138
4,200
.0008
.Ol6
16,000
.0089
,
.178
4,400
.0009
.Ol8
18,000
.0113
.226
4,600
.0010
.020
20,000
.0209
,
.418
5>ooo
.0011
.022
22,000
• 0309
.618
5,400
.0012
.....
.024
24,000
.0444
g
.888
6,000
.0013
.026
26,000
.0589
,
1.178
7,000
.0015
.030
28,000
.0779
.
1.558
8,000
.0017
•054
30,000
.1019
.
2.038
9,000
.OO22
•044
32,000
• 1391
.
2.782
11,000
.0029
.0^8
34,000
.1171
2.342
12,000
.0036
.072
36,000
.2181
4-362
14,000
.0050
.100
36,540
Broke.
15,000
16,000
17,000
.0060
.0070
.0082
.120
.140
.164
Tenacity per square inch, original section,
36,540 pounds (24.68 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
300
2,000
.0020
0016
.032
.040
41,028 pounds (28.84 kgs. per sq. cm.).
Diameter of fractured section, 0.753" (1.9 cm.).
4,000
.0025
.050
BAR NO. 12 B-D.
COMPOSITION.— Original mixture : Cu, 58.22; Sn, 2.30; Zn, 39.48.
300
30,000
.0240
.48
1,000
.0012
....
.024
32,000
.0254
.508
2,000
.OO22
....
.044
34,000
.0268
.536
2,200
.0024
....
.048
36,000
.0282
!!!!
.564
2,400
.0026
....
.052
38,000
.0297
....
• 594
2,000
.0028
....
.056
40,000
.0313
....
.626
2,800
.0030
....
.ODD
300
.0150
.030
3,000
.0032
....
.064
10,000
.0215
....
•43°
3,200
.0034
....
.068
20,000
.0279
.558
3.400
.0036
....
.072
30,000
• 0345
....
.690
3,600
.0038
....
.076
40,000
.0299
....
•798
3,800
.0041
....
.082
42,000
.0423
....
.846
4,000
.0044
....
.088
44,000
.0447
.894
5,000
.0054
....
.108
46,000
.0473
....
.946
6,000
.0064
....
.128
48,000
.0494
.988
7,000
.0074
....
.148
50,000
.0527
....
•°54
8,000
.Oo8l
....
.162
52,000
.0568
.136
9,000
.0098
.176
54,000
.0615
.23
10,000
.0085
....
.190
56,000
.0674
..!.
• 348
300
0022
.044
58,000
.0771
....
• 542
10,000
.0113
.226
60,000
.0873
.746
12,000
.0125
....
•25
62,000
.0958
.916
14,000
•OI37
.274
64,000
.1277
•554
l6,OOO
l8,000
.0150
.0165
•30
•33
66,000
67,000
„ -1577
Broke.
3.154
2O,OOO
22,000
24,000
26,000
28,000
.0176
.0189
.0202
.0213
.0226
•352
•378
.404
.426
.452
Tenacity per square inch, original section,
67,600 pounds (47.52 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
73,160 pounds (51-43 kgs. per sq. cm.).
Diameter fractured section, 0.767" (1.9 cm.).
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIL— Continued.
BAR NO. 40 B.
COMPOSITION.— Original mixture : Cu, 50; Sn, 5 ; Zn, 45.
M
2 &•
M
2 h
i
« O
M
« O
J3
D
£*
4
*$
S£
*
*fc
«5
£2
O
O
£
SET.
ELONGATIC
PER CE
LENGTH.
si
Q
s
1
1
SET.
ELONGATIC
PER CE1
LENGTH.
Pounds.
Inch.
Inch.
fiftm^t.
Inch.
Inch.
300
14,000
.0126
.....
.252
1,000
.0009
'.Oik
16,000
.0141
.282
2,000
.0018
.036
18,000
•OI55
.310
2,500
.0022
.044
20,000
.0169
.338
3,000
.OO25
.....
.050
300
.0005
• . * *
3.500
4,000
.0028
.OO22
3
I,OOO
22,000
.0184
.0013
^368
300
.0000
....
24,000
.0195
•39°
1,000
.0009
26,000
.0205
.410
4,000
.OO32
.064
28,000
.0215
'43°
6,000
.OO5I
. IO2
30,000
.0225
• 450
8,000
10,000
300
1,000
10,000
12,000
.0069
.0087
.OO92
.0107
.0002
.0011
.138
.174
'.i86
.214
31,300 Broke.
Tenacity per square inch, original section,
31,300 pounds (22.00 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
31,300 pounds (22.00 kgs. per sq. cm.).
Diameter of fractured section, 0.798" (2 cm.).
BAR NO. 52 B.
COMPOSITION.— Original mixture : Cu, 60 ; Sn, 5 ; Zn, 35.
300
300
0007
1,000
.0006
.012
20,000
0092
....
!is4
2,000
.0018
.036
22,OOO
0098
.196
2,500
.0023
.046
24,000
0105
.210
3,000
.0026
.052
26,000
0114
.228
3i5°o
.0030
.060
28,OOO
0125
....
.250
4,000
.0033
.066
30,000
0138
.276
300
.00005
....
300
0026
1,000
.0006
30,000
0144
....
4,000
.0027
....
32,000
0153
....
[306
6,000
.0035
.070
34,000
0165
8,000
.0046
.092
36,000
0182
....
.364
10,000
.0054
.108
38,000
_ OI99
....
.398
300
10,000
12,000
14,000
.0019
.0058
.0068
.0001
!*36
38,330 Broke.
Tenacity per square inch, original section,
38,300 pounds (26.95 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
16,000
18,000
.0076
.0083
.152
.166
38,534 pounds (24.84 kgs. per sq. cm.).
Di imeter of fractured section, 0.797" (2 cm.)
20,000
.0090
.180
i
STRENGTH OF C&PPER-ZINC-TIN ALLOYS.
TABLE LXXXIL— Continued.
BAR NO. 59 A.
COMPOSITION.- Original mixture : Cu, 70 ; Sn, 5 ; Zn, 25.
457
1
-
S5fa
•
- o
i
w O
D
5
.
C*
•£
Z E"1
o*
z
§H
'•S. M
o
O M •
1/3 a
o
u •
£5
p
SET.
l°l
gs
i
SET.
§U5
Q
z
£ fri W
Q
•
£ W M
s
3
M
§'J
3
o
J
M
M
Pounds.
Inch.
Inch.
Pcutnls.
Inch.
Inch.
300
300
0004
1,000
.0004
!oc8
20,000
•0133
....
2,000
.0009
.018
22,000
.0171
• 342
2,500
.0012
.024
24,000
.0233
....
.466
3,000
.0014
.028
26,000
.0296
....
.596
2,500
.OOl6
.032
28,OOO
.0376
....
• 752
4,000
.0018
.036
30,000
.0472
....
•944
300
.0000
300
0078
1,000
.0004
30,000
.0470
....
4,000
.00l8
.....
....
32,000
• 0517
1.034
6,000
.0023
.046
34,000
.0684
....
1.368
8,000
.OO29
.058
36,000
.0838
1.676
10,000
300
10,000
12,000
14,000
16,000
18,000
.0036
!oo38
.0046
.0059
.0079
.0098
.0002
.072
.092
.118
.158
.196
38,000 .1028? 2.056
Broke just after reading was taken.
Tenacity per square inch, original section,
38,000 pounds (26.61 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
39,014 pounds (27.43 kgs. per sq. cm.).
Diameter of fractured section, 0.788" (2 cm.).
20,000
.0129
.258
BAR NO. 67 A.
COMPOSITION.— Original mixture : Cu, 80 ; Sn, 5 ; Zn, 15.
300
20,000
.0632
1.264
1,000
.0012
....
.024
300
.0518
2 OOO
_-
nej.
2O OOO
06^8
2,5OO
.0036
....
*W54
.072
22,000
.WjO
.0847
1.694
3,000
.0044
.088
24,000
.1150
.....
2.300
31500
.0050
....
.100
26,000
.1582
3.164
4,000
.0056
.112
28,000
.2650
4. loo
300
0003
....
30,000
.2642
5.284
4,000
.0059
....
300
....
.2502
5.004
5,000
.0069
....
.138
30,000
.2682
5.364
6,000
.Oo8l
....
.162
32,000
.3422
6.844
8,000
.0111
.222
34,000
.4127
8.254
10,000
.0150
....
.300
36,000
.5022
10.044
300
1,000
0038
0052
Broke.
.5804
II. 608
10,000
12,000
I4,OOO
16,000
18,000
.0157
.0198
.0271
.0346
.0469
'.'.'.'.
096
:«:
.938
Tenacity per square inch, original section,
37,560 pounds (26.40 kgs. per sq. cm.).
Tenacity per square inch, fractured section,
48,905 pounds (34.38 kgs. per sq. cm.).
Diameter of fractured section, 0.700" (1.78 cm.).
458 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXII.— Contimted.
BAR NO. 73 A.
COMPOSITION.— Original mixture: Cu, 55; Sn, 0.5; Zn, 44.5.
LOAD PER SQUARE
INCH.
ELONGATION AND
SET IN INCHES.
ELONGATION AND
SET IN PER CENT.
OF LENGTH.
MODULUS OF ELAS-
TICITY.
LOAD PER SQUARE
INCH.
ELONGATION AND
SET IN INCHES.
ELONGATION AND
SET IN PER CENT.
OF LENGTH.
MODULUS OF ELAS-
TICITY.
Pounds.
300
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
300
10,000
12,000
14,000
16,000
l8,000
20,000
300
20,000
22,OOO
24,000
20,000
28,000
300
28,000
3O,OOO
32,000
34,000
Inch.
Pounds.
36,000
38,000
40,000
300
40,000
42,000
44,000
46,000
48,000
50,000
52,000
300
52,000
54,000
56,000
58,000
60,000
300
60,000
62,000
64,000
68,900
Tenacity
68,900]
Tenacity
92,136
Diamete
cm.).
Inch.
:3B
.0748
Set .05535
.07815
.09025
•"97
.1393
.16255
.2006
.2259
Set .19825
•"955
.26605
.29875
.3263
.3720
Set .3496
•3991
.4636
• 4714
Broke,
per square
aounds (48.4^
per square
Dounds (64.77
r of fracture
.946
I.I72
1.496
Set 1.107
1.563
1.805
2.394
2.786
3-251
4.014
4.518
Set 3.965
4-591
5.321
1:111
7.440
Set 6.992
7.982
9.272
9.428
inch, origin
nch, fractur
kgs. per sq.
d section, .
.00025
.00065
.OOII
.00155
.00195
.0024
.00295
.0035
.0038
.0042
Set .00005
.0042
.0052
.0062*
.0072
.0082
.0089*
Set .00055
.0095
.0109
.01265
.01485
.0178
Set .00515
.01815
.02235
.02755
.03625
.005
.013
.022
.031
'.III
.059
.070
.076
.084
Set .001
.084
.104
.120
.144
.164
.179
I5>383,°76
13,636,363
12,903,258
12,820,512
12,500,000
11,868,474
11,428,571
11,842,105
11,904,761
2»673,796
1,245,762
11,538,461
11,200,000
II, III, III
10,975,668
11,172,184
.100
.218
•253
.297
.356
10,009,082
9,494,07!
8,755,555
7,865,168
al section,
cm.).
;d section,
cm.).
5900" (i.7S
.363
• 447
.725
STRENGTH OF COPPER ALLOYS.
459
TABLE LXXXIIL
TESTS BY TRANSVERSE STRESS.
ALLOYS OF COPPER, TIN AND ZINC.
DIMENSIONS. — Length, 1=22" (55.88 cm.); breadth, b = i.oo" (2.54 cm.);
depth, d— i.oo" (2.54 cm.).
COMPOSITION.— Original mixture : Cu, 70 ; Sn, 8.75 ; Zn, 21.25. Analysis : Cu, 70.22 ; Sn, 8.90;
Zn, 20.68.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
1
10
20
40
60
80
100
120
160
2*0
10
3
200
240
280
320
360
400
10
4
400
44°
480
520
e°
600
10
600
&
72°
760
800
10
800
840
880
920
960
1,000
Inch.
.0004
.0018
.0067
.0125
.0172
.0215
.0250
.0287
.0359
•0437
•0435
.0500
.0568
.0635
.0702
.0764
.0764
.0825
.0891
.0960
.1022
.1086
iioSi
• "57
-.1234
.1305
.1380
.1468
.1464
.1549
.1627
.1716
.1808
.1905
Inch.
Pounds.
10
Left 10 n
resista
1,000
Left und
Resistan
Resistan
Resistan
1,000
1,010
1,020
1,040
1, 060
1, 080
1,120
I, l6o
1,200
1O
Resistan
Decrease
1,200
1,240
1,280
1,320
Inch.
iin. ; showed
nee.
er strain.
:e diminishet
:e diminishec
:ediminishec
• 1951
.1967
.1994
•2033
.2081
• 2145
.2259
• 2373
• 2515
:e increased
of set, .0004
• 2536
.2634
.2785
.2962
•3*43
• 3351
'3351
.35i6
.3713
.4019
Broke sudd
sound,
load, P = i,
of rupture, J\
Inch.
.0132
.0098
very slight
ncrease of
0018
0003
0050
0009
0054
0001
7,820,389
8,383.4:>7
9,T38,945
9,748,166
10,498,644
io,953,995
11,948,989
11,990,718
1 in 5 min. to 996 Ibs.
I in 20 min. to 990 Ibs.
inihr. 55 m. to 985 Ibs.
12,575,185
12,914,657
13,202,297
13,434,278
13,716,389
.0291
.0261
n 20 min. to
.0257
12,500,184
9 IDS.
!3>972,399
14,113,565
14,190,748
14,355,235
14,474,203
1,360
1,400
10
3
10
1,400
1,440
1,480
1,520
i,55o
ringing
Breaking
Modulus
metric)
.0721
.0681
.0697
10,945,277
0056
0026
14,491,715
14,436,664
14,454,236
14,428,053
14,277,003
enly in middle, with
550 Ibs.
'=2^ = 5°.54l(3,553
:::
14,206,957
14,169,948
14,045,709
13,910,603
I3,752,39°
460 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIII.— Continued.
BAR NO. 5.
COMPOSITION.— Original mixture : Cu, 88.135 ; Sn, 1.865 ; Zn, 10. Analysis: Cu,
89.50; Sn, 2.07; Zn, 8.11.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
2
O
H
Q
SET.
MODULUS OF
ELASTICITY.
Pounds.
3
10
20
£
80
100
120
160
209
10
3
200
240
280
320
360
400
10
3
400
440. beam s
480
520
560
600-
10
Left und
Resistan
Inch.
.0018
.0071
.0119
.0162
.0190
.0224
.0255
.0314
•0379
.0381
.0436
.0511
.0584
.0658
.0727
'.0749
inks. .0830
.0921
.1086
.1309
.1631
.1695
tr strain,
ce diminishec
Inch.
Pounds.
Resistanc
Resistan
600
620
640
680
720
760
800
10
800
840
860
880
900
920
940
960
980
1,000
,020
,040
,060
,080
,100
,120
Bar rer
Breakin
Moduli
(metri
Inches.
:e diminishec
:e diminishe<
•5394
.6984
.9199
.9859
.1389
.26
•36
.56
•74
.92
.12
•32
•52
•72
•92
3-27
3.67
noved
g load, /*=!,
is of ruptur
c, 2,250).
Inch.
[ in 4 min. to
1 in 41 min. t
578 Ibs.
o 570 Ibs.
.0101
.0059
5,325.416
7^001 ',935
7,960,094
8,439,831
8,896,573
9,633.235
9.976,370
!s68J
2,164,546
.
.0234
.0162
10,359,026
10,359,028
10,343,283
IO,4QI,776
10,022,046
9,852,884
.0849
.0820
6,954,660
120 pounds
C, R — • — 7~~^r
-^
1 in i min. to 584 Ibs.
BAR NO. 7.
COMPOSITION.— Original mixture: Cu, 66.885 ; Sn, 1.865 ; Zn, 31.25.
3
10
20
£
120
J6o
200
10
3
200
840
280
320
360
400
IO
3
400
.0024
.0^55
.0114
.0201
.0281
.0367
.0447
.0443
.0513
.0603
.0678
.0748
.0831
.'0836
440
480
520
£
600
10
60!
Left und
Resistan<
Resistan
Resistan
10
Left und
Resistan
58?
600
.0920
.1012
.Hog
.1239
.1402
•1433
er strain.
:e diminishe(
:e diminishec
:e diminishec
er strain.
:e increased
.1400
.1440
Beam sinks.
.0257
.0233
[ in 3 min. tc
1 in 10 min. t
lin i6h. ism
.0290
.0274
n TO min. to
.0273
12,756,821
12,651,391
11,415,131
.0060
.0041
9,699,400
9,359,I72
10,616,259
",390,754
11,628,709
",934,387
596 Ibs.
o 594 Ibs.
to 58 1 Ibs.
.0091
.0066
12,478,758
12,385,635
12,589,165
12,837,309
12,839,159
5 Ibs.
..
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIII. (Bar No. 7).— Continued.
461
LOAD.
Pounds.
620
640
680
720
760
720
760
800
10
3
Sol
840
880
920
960
1,000
10
3
1,000
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Inch.
.1496
.'575
.1836
.2128
.2642
.3069
• 3099
.3471
.4296
.5156
.6145
• 7"7
.7169
Inch.
Pounds,
1,040
i, 080
1,120
1,160
1,200
1,240
1,280
1,320
1,360
1,400
1,440
1,480
1,500
Bar rem<
Breaking
Modulus
(metric,
Inches.
•7799
.9498
1.0549
1.19
L37
L57
J-73
l-93
2.13
2.33
2.61
3-"
3-76
Inches.
^387
• 1343
• 1334
6,952,976
3.32
00.
?-^ =
~ 2^2
>ved.
' load, /)=i,s
of rupture, *
3,417)'
49,599
:ji
3i747A36
BAR NO. 12.
COMPOSITION.— Original mixture: Cu, 58.22 ; Sn, 2-30; Zn, 39.48.
3
10
20
&
120
160
200
TO
3
200
240
280
320
300
400
10
3
400
%
S
600
10
60!
640
680
720
760
800
.0024
.0046
.0098
.0202
.0206
.0418
.0517
.0532
.O6l2
.0712
.0802
.0008
.IOOO
.1010
.1095
•"97
.1294
• 1403
.1511
.1515
.1629
::$
.1944
.2038
10
«J
840
880
920
960
1,000
10
3
1,000
1,040
1, 080
I,I2O
1,160
.1,200
IO
3
1,200
Left und
Resistam
1,240
1,280
1,320
1,360
1,400
IO
3
1,400
1,440
1,480
1,520
.2028
.2142
.2247
•2344
•2433
-2550
^2544
.2642
.2764
.2847
.2951
.3062
3069
ir strain.
:e diminishec
.3170
.3276
.3398
• 3528
•3673
• 3695
-3817
-3959
.4102
.0043
.0032
.0032
.0011
.0027
.0008
11,760,504
11,040,471
",7r2,535
10,965,874
io5353,743
10,463,891
.0064
.0046
.0114
.0093
1 in 55 min. t
10,607,511
io,593,349
10,616,562
10,672,909
10,607,511
10,607,511
10>637,3o6
10,792,679
10,724,336
10,819,661
10,647,661
10,569,132
10,641,044
10,632,674
10,600,509
o 1,194 Iba,
.0032
.0015
10,869,067
10.846,777
10,869,829
11,578364
14,321,101
10,627,046
10,570,934
10,550,048
!o,574,77i
10,617,922
.0210
.0193
10,310,049
462 MATERIALS OF ENGINEERING— NON-FERROUS METALS
TABLE LXXXIII. (Bar No. 12).— Continued.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
i, «>6o
i, 600
10
1,600
1,640
1,680
1,720
1,760
i, 800
10
Il8ol
1,840
1,880
1,920
1,960
2,000
10
Left unde
Resistanc
3
2,000
2,040
2,o8o
2,120
2,160
2,200
2,240
2,280
Left unde
Resistanc
Resistanc
Resistanc
Resistanc
2,280
2,290
2,300
2,310
2,320
Left unde
Resistanc
Resistanc
Resistanc
2,270
2,280
2,290
2,300
2,310
2,320
2,330
2,340
2,350, beair
Lett unde
Resistanc
2,350
2,360
2,370
Inch.
.4236
•4395
• 4405
•4537
.4704
.4882
.5042
•5203
.5230
•*ll
.5586
•5823
.6076
.6343
r strain.
; increased ii
• 6390
•$&
.7140
.7486
•7777
.8106
.8621
r strain.
z decreased i
z decreased i
e decreased i
5 decreased i
.8665
.8685
.8-22
.8763
.8843
r strain.
s decreased i
2 decreased i
e decreased ii
.8867
.8893
.8919
.8948
.8967
.8990
.9019
.9063
sinks. .9165
r strain.
; decreased i
.9189
• 923Q
.9418
Inch.
Pounds.
2,380
2,390
2,400
2,410
2,420
2,430
2,440
2,450
2,460
2,470
2,480
2,490
2,500
2,510
2,520
2,530
2,540
2,550
2,560
2,57°
2,580
2,59°
2,600
2,610
2,620
2,630
2,640
2,650
2,660
2,670
2,680
2.690
2,700
2,710
2,720
2,730
2,740
2,750
2,760
2,770
2 -80
Inches.
•9529
.9650
.9764
.9888
.0048
.0189
•0333
.0438
•°553
•0755
.0865
.1013
.1265
• 1341
.1475
.1647
.1818
.1918
.2073
.2293
•2445
•2585
.2851
.3063
•3^88
.3406
•3556
•3747
•3973
.4178
•4447
.4665
.4898
•5057
•5303
•5437
.5603
.6106
.6279
.'6899
.7285
•7599
•7793
.8111
.8553
.8807
.8936
•9453
.9881
Broke grad
Jtting on sti
was heard
'?•
load, P=2,
of rupture,
/? 3/V
ff=^* =
Inch.
.0407
.0387
9,847,245
.0743
.0727
9.354,174
....
.1340
.1326
i 10 min. to 8
.1320
8,955,262
Ibs.
5472,55*
7,651,812
n i min. to 2,272 Ibs.
n 3 min. to 2,268 Ibs.
n 25 min. to 2,260 Ibs.
i hr. to 2,256 Ibs.
n 3 min. to 2,312 Ibs.
n 10 min. to 2,308 Ibs.
1 66 hr. 13 m. to 2,260 Ibs.
2,790
2,800
2,810
2,820
2,830
2,840
2,850
2,860
2,870
2,880
2,890
While pi
sound
breakir
Breaking
Modulus
4,331,697
ually in the middle,
•ain a slight crackling
a few seconds before
38o pounds.
95,623 (metric, 6,722).
n 10 min. to 2,342 Ibs.
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIIL— Continued.
BAR NO. 52.
COMPOSITION.— Original mixture : Cu, 60 ; Sn, 5 ; Zn, 35.
LOAD.
Pounds.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
$2
600
10
6d
640
680
720
760
800
§
D
Q
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Inch.
.0017
.0036
.0073
.0148
.0237
.0327
.0408
.0411
• °583
.0656
• 0713
.0770
.0777
.0839
.0915
•°993
.1068
•"37
.1148
.1216
.1285
.1353
.1420
.1487
Inch.
Pounds.
Inch.
Inch.
.0058
.0036
*
3
800
840
Beam sin!
880
92°
960
1,000
IO
3
1,000
,040
,080
,120
,160
,200
• 1495
. '15SS ,
nng a little.
.1626
.1698
.1774
.1857
!i8s8
.1935
.2032
.2126
.2221 ,
.2324
.0022
.0006
14,805,645
14,602,823
I4,389,I92
13,477,585
13,039,862
13,063,832
.0063
.0039
J4,395,26l
14,423,245
14,439,425
14,421,764
14,351,218
.0026
.0008
12,869,320
12,704,416
72,704,190
'5,455,931
13,844,270
14,324,630
.0098
.0072
13,760,839
3
1,200
1,240
1,280
1,320
1,360
1,400
.2330
.2426
•2547
.2639 '
.2722
.2804
.0047
.0026
13,975,955
13,980,442
13,955,804
13,973,864
14,063,440
.0157
.0136
i inch from t
402 po unds.
R 3/Y
13,275,464
3
1,402
Breaking
Modulus
(metric
Broke about
load, P = i,
of rupture
, 3,239).
;:;;;
14,626,432
14,102,841
14,181,934
14,263,500
14,336,709
he middle.
= 46,076
*R ~ *bd*
BAR NO. 55.
COMPOSITION. — Original mixture : Cu, 65 ; Sn, 5 ; Zn, 30.
0856
14,191,208
IO
.0018
480
0931
14,234,223
20
40
80
.0037
.0081
.0168
'::•:.
14,023,498
13,633,811
i3,I46,888
520
fe
600
<&
1058
1129
.0038
14,530,772
14,613,175
14,672,351
1 60
200
.0422
13,084,581
600
1129
14,786,125
3
.0001
680
1265
14,840,914
14,812,293
240
280
•"4J1
.0506
.0581
I3,°94i924
13,305,285
Pf*
760
800
1420
1495
14,776,364
14,776,762
360
O?8l
8oo3
1498
IO
.0028
840
1586
14,622,290
3
.0015
880
1680
14,461 578
400
.0781
020
1706
I4.I42,4I>
464 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIII. (Bar No. ^.—Continued.
LOAD.
Pounds.
960
1,000
IO
3
1,000
1,040
1, 080
1,120
1,160
1,200
io
3
1,200
1,240
1,280
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Inch.
.1906
.2047
.2072
.2185
.2382
•2579
.2789
.3014
.3036
.3272
•3580
Inch.
.0196
.0177
13,905,628
13,487,282
Pounds.
1,360
1,400
IO
Inch.
.3716
.4039
• 4433
Inck.
.1421
.1397
8,719,013
3
1,400
1,440
1,480
1,520
Breakin
Modulu
(metri
.'4508
.4704
.5165
.5608
Broke in th
g load, P —
5 of rupture
c, 3614).
.0597
.0576
e middle.
1,525 pounds
'* = lA?
f = 51i369
10,912,409
BAR NO. 64.
COMPOSITION. -Original mixture : Cu, 75 ; Sn, io ; Zn, 15.
3
10
20
40
80
1 20
160
200
10
3
2OO
240
280
320
360
400
10
3
400
je
S20
560
600
IO
600
640
680
720
760
800
10
^
840
880
920
.0019
.0036
.oo63
.0143
.0229
• 0313
.0389
!o39o
.0468
.0549
.0027
.0702
.0776
• 0775
.0843
.0907
.0971
• I035
.1107
."IS
.1-79
.1251
.1323
•1395
.1472
.1482
.1557
.1647
.1738
960
1,000
IO
3
1,000
1,040
1, 080
1,120
1,160
1,200
IO
3
1,200
1,240
1,280
2,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,560
i, 600
10
1,600
1,640
i, 680
1,720
1,750
Breaking
Modulus c
.1847
.1979
.2001
.2113
.2258
.2438
.2661
.2858
.2927
.3077
.3286
.3536
.3816
.41"
!4i86
•44*3
• 4795
.5234
• 5598
•5947
.6090
.6399
•6755
Broke near t
oad, P= 1,7
f rupture,
Jf 3/V
R =ri* ~ 5i
.0224
.0195
14,148,277
I3,754>775
.0024
.0002
.OO26
.0003
15,122,613
l6,OI2,I77
15,228,364
14,264,12!
13,914,737
13,995,219
.0637
.0607
11,429,344
13,959,331
13,883,543
13,892,545
*3,959,33i
14,031,290
.1473
• 1443
9,270,002
.0049
.OO2I
14,207,721
14,405,661
I4,577,5"
14,728,108
14,752,853
.2840
.2798
.008l
•0057
14,776,293
14,796,224
14,813,990
14,829,914
14,793,825
tie middle.
50 pounds.
5,345 (metric,
4,102).
•"••
14,685,542
I4,544,i5i j
14,409,115
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIIL— Continued.
BAR NO. 68.
COMPOSITION.— Original mixture : Cu, 80; Sn, 10 \ Zn, 10.
465
LOAD.
Pounds.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
440
480
520
560
600
10
60*
640
680
720
760
800
10
fcj
840
880
920
960
1,000
JO
3
1,000
1,044
1,080
1,120
1,160
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
Sg
SG
is
§3
9,372,595
Inch.
.0019
.0038
.0072
.0132
.0210
.0291
•0374
•0374
.0456
.0536
.0617
.0699
.0786
.0853
.0921
.0991
.1063
. II2O
•"37
.1208
.1286
.1365
.1444
.1526
.1528
.1621;
.1725
.1839
•1955
.2126
'.2166
.2323
.2527
•2789
.3066
Inch.
Pounds.
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,56°
i, 600
10
,,<bl
1,640
i, 680
1,720
1,760
i, 800
10
3
i, 800
1,840
i, 880
1,920
1,960
2,000
2,040
2,060
Rollers fle
iron sup
with a tc
Zoefficien
Breaking
Modulus o
R
Inches.
•3325
• 3419
.3627
.4037
.4400
•4934
.5647
.5720
.6010
.6449
•7H3
.7921
.8645
!88o8
.9409
.0216
• "57
.2321
.3417
.'3689
• 4464
• 5879
.7029
.8499
.0079
.2849
•4479
w apart. Cc
ports. Theb;
)tal deflectio
of elasticity
oad, P = 2,01
f rupture,
3^ fi,
Inch.
.1171
0025
0006
13,668,369
14,427,725
15,739,337
14,839,942
14,278,983
13,887,648
.2951
.2934
6,438,437
0067
0053
13,668,369
13,566,365
13,468,990
I3,379,554
13,266,871
'3,395,96i
I3,534,458
13,626,987
13,681,226
13,911,448
'.5468
• 5432
4 806,460
0150
0130
'3,759,793
13,732,139
13,698,407
13,668,368
13,614,630
^589
.9546
3,484,072
2,586,772
mtinued tests on cast-
ir broke at 2,320 pounds
i of 2.797".
, 2,154,099.
5o pounds.
117 (metric, 4,718).
.0417
.0405
12,215,380
~2^-67
30
4-66 MATERIALS OF ENGINEERING— NON-FERROUS ME TALS.
TABLE "LXXXllL— Continued.
BAR NO. 71.
COMPOSITION.— Original mixture : Cu, 85 ; Sn, 10 ; Zn, 5.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
j
i
SET.
MODULUS OF
ELASTICITY.
Pounds.
3
10
20
40
90
1 20
160
200
IO
3
200
240
280
32°
360
400
IO
3
400
440
480
520
560
600
IO
600
640
680
720
760
800
IO
800
840
880
920
960
Left unde
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Q20
940
945
950
955
Inch.
.0013
.0031
.0064
.0131
.0201
.0275
•0355
.0364
.0426
.0508
.0589
.0670
.0752
•°759
.0842
.0919
.0998
•I°73
• "35
.1141
.1138
.1270
•I347
.1425
.1501
.1506
.1598
.1691
r strain.
; decreased ii
". decreased ii
decreased ii
. decreased ii
• decreased ii
decreased ii
decreased ii
- decreased ii
: decreased ii
: decreased i
; decreased i
: decreased i
.1896
.1914
.1920
•1943
.1951
Inch.
Pounds.
960
965
970
975
980
985
990
1,000
10
3
1,000
1,040
1, 080
1,120
1,160
>ft unde
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
Resistance
i, 066
1,100
I, IIO
1,120
1t13°
i,i35
1,140
Inch.
.1958
.1969
.1983
.1994
.2005
.2017
.2031
.2066
.2078
.2166
.2306
• 2537
.2832
r strain.
: decreased i
; decreased i
: decreased i
; decreased ii
; decreased i
; decreased i
; decreased i
i decreased i
: decreased i
: decreased ir
• 2833
.2897
.2914
.2937
.2958
.2970
.2986
.3005
.3023
.3045
.3076
.3110
.3Hr
.3175
.3221
.3304
0305
• 35"
.3691
.4204
.5296
• 5500
.6052
.6534
•7350
.8214
Inch.
.0024
.0015
1 5,737,217
15.245,428
14,896,295
I4,562,759
14,192,108
'3,742,357
.0397
.0382
II,8o6,720
.0042
.0026
!oo68
.0051
X3,742,357
13,444,786
13,252,393
13,106,516
12,974,833
n 2 min. to 1,118 Ibs.
i 3 min. to 1,112 Ibs.
i 4 min. to i, no Ibs.
i 7 min. to 1,104 Ibs.
i 12 min. to i, too Ibs.
i 27 min. to 1,093 Ibs.
a 42 min. to 1,090 Ibs.
i i hr. i2m. to 1,087 Ibs.
i 2 hr. 1 2m. to 1,082 Ibs.
16 hr. i2m. to i,o66lbs.
12,746,771
12,740,466
12,709,614
10,730,571
12,906,151
.0134
.0116
13,03*, *52
13,060,650
13,038,405
13,009,431
13,000,763
i,t45
1,150
M55
1^165
1,170
i,i75
1,180
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
IO
3
1,400
1,440
1,480
1,520
1,560
i i min. to 944 Ibs.
i 2 min. to 940 Ibs.
i 3 min. to 938 Ibs.
i 4 min. to 937 Ibs.
i 9 min. to 932 Ibs.
i 14 min. to 930 Ai Ibs.
i 29 min. to 926 Ibs.
i 44 min. to 925 Ibs.
i i hr. 14 min. to 9^ Ibs.
i i hr. 44 min. 10922 Ibs.
i 2 hr. 44 min. to 920 Ibs.
i 2 hr. 74 min. to 920 Ibs.
,'ii66
.1141
8,859,329
:|j
6,448,116
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIII. (Bar No. 71).— Continued.
46;
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
\
LOAD.
|
h
M
Q
SET.
MODULUS OF
ELASTICITY.
Pounds.
i, 600
10
i, 600
,640
,680
'720
,760
,800
,840
,880
Inches.
.9206
Inch.
Pounds.
1,920
1,960
2,000
The bea
crease
Breaking
Modulus
,
Inches.
2.0401
2.3676
2.5621
m could not
of load,
load, /> = 2,
of rupture,
R-*Pl -
zbd?
Inch.
.6169
be raised with an in-
ooo pounds.
62,470 (4,392 metric).
.9486
.0198
.1191
.2726
18556
BAR NO. 72.
COMPOSITION. — Original mixture : Cu, 90; Sn, 5 ; Zn, 5.
3
10
20
£
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
&
600
10
6<J
640
Left unde
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
£
6>S
.00l8
.0036
.0069
•0145
.O22I
.0297
•°374
.0376
.0461
•0535
.0608
.0681
•0754
•°757
.0827
.0907
.0992
.1092
.1202
.1246
r strain.
: decreased i
s decreased i
2 decreased i
s decreased i
z decreased i
e decreased i
e decreased i
e decreased i
e decreased i
e decreased i
e decreased i
.1342
.1387
.1392
630
635
640
645
650
655
660
680
720
760
800
10
8<J
840
Left und
Resistan
Resistanc
Resistan*
Resistan
Resistanc
Resistanc
Resistan
Resistanc
Resistanc
Resistan
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistanc
Resistam
Resistanc
752
780
800
820
825
830
!35
840
•1397
.1406
.1426
.1441
•1456
•1473
•1525
.1701
.1969
.2287
.2451
.2814
er strain.
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
:e decreased
•e decreased
:e decreased i
,e decreased
e decreased
.2814
.2865
.2900
• 2951
33
•3°5°
.3094
.0035
.0019
.0071
.0049
.0246
•0233
14,3°9i323
14,862,866
14,145,348
13,921,359
13,811,961
I3,7^»398
13,347,532
13,418,250
13,493,919
I3.553i364
13,601,300
13,640,770
13,568.306
i3,439,5°4
13,180,961
12,797,923
.0997
.0979
8,968,410
in i m. to 800 Ibs.
in 2 m. to 795 Ibs.
in 3 m. to 792 Ibs.
in 4 m. to 790 Ibs.
in 5 m. to 789 Ibs.
in 6 m. to 788 Ibs.
in 13 m. to 782 Ibs.
in 21 m. to 779 Ibs
in 31 m. to 777 Ibs.
in 46 m. to 774 Ibs.
in i hr. i m. to 772 Ibs.
n i hr. i6m. to 771 Jibs,
in i hr. 46 m. to 770 Ibs.
in 3 hr. i m. to 766 Ibs.
in 4 hr. i m. to 764 Ibs.
in 5 hr. 31 m. to 763 Ibs.
n 21 hr. 15 m. to 752ilbs.
in 23 hr. 45 m. to 752 Ibs.
n 24 hr. 36 m. to 752 Ibs.
i i m. to 628 Ibs.
n 2 m. to 626 Ibs.
n 3 m. to 624 Ibs.
n 4 m. to 623 Ibs.
n 5 m. to 622 Ibs.
n 6 m. to 621 Ibs.
n ii m. to 618 Ibs.
n 16 m. to 617 Ibs.
n 19 hrs. 51 m. to 596 Ibs.
n 40 hrs. 36 m. to 591 Ibs.
n 42 hrs. ii m. to 591 Ibs.
i
:::
468 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIII. (Bar No. 72).— Continued.
„
u. .
|
fc rf
LOAD.
g
SET.
j§ y
LOAD.
SET.
sl
w
D en
w
2 [jj
\
la
i
i -
Pounds.
Inches.
Inch.
Pounds.
/WA^.
Inch.
845
1 108=;
850
i 160
860
•33*7
1 802?
1,620.000
880
*
920
960
.4320
.5587
1,280
The bean
2.6325
i roiilrl nr»t
h*» rais*»H with an in.
1,000
10
3
.7191
3,565,351
crease of weight.
Breaking load, P — 1,280 pounds.
Modulus of rupture
I,OOO
g
1,040
1, 080
I.IOOI
R = ^-r-™ = 4i»334 (a»9o6 metric).
BAR NO. 73.
COMPOSITION. — Original mixture : Cu, 55 ; Sn, 5 ; Zn, 44.5.
3
10
20
C
Z20
1 60
200
10
3
200
240
280
320
360
400
10
3
400
$
E
600
10
6.4
640
680
720
760
800
10
80?
840
880
920
960
1,000
10
3
1,000
1,040
1, 080
1,120
1,160
1,200
.0021
.0051
.0122
.O2I7
.0321
.0417
.0519
.0520
.0631
•0734
.0813
.0899
.IOOI
.0997
.1102
.1199
.1300
.1402
.I5l6
.1518
.1623
.1745
.l88l
.2O24
.2164
.2167
.2296
.2443
.2585
.2758
.2923
!2948
.3146
•3338
•3571
.3851
.427I
10
3
1,200
1,240
I,28o
1,320
1,360
I,4OO
10
Left und
Resistam
Resistam
10
3
1,400
1,440
1,480
1,520
1,560
1,600
1,640
i, 680
1,720
1,760
i, 800
10
i, 800
1,840
i, 880
1,920
i,96o
2oOO
10
3
2,000
2,000
2,040
2,o8o
2,IOO
Breaking
Modulus
(
.4284
• 4575
•4973
•5390
.5076
.6419
sr strain.
-e increased
:e increased
.2970
.2933
.6508
.7197
• 7853
• 8571
.9485
1.0361
1-1295
1.2316
1-3347
1-4535
J-5744
i '. 5866
1-7459
1.8619
2.0244
2.2087
2.3178
*-35i3
2.7738
3.0498
3.0498
Beam coul
this pres
load, P = 2,
of rupture,
*-§«.-,
2W '
.1286
.1265
.0024
.OO24
11,125,506
9,301,654
10,459,002
10,605,623
10,885,388
I0,932,579
12986
.2965
n 20 m. to s\
n 15 hrs. 45 n
6,187,577
Ibs.
i. to 10 Ibs.
Ioo28
.0008
10,790,506
10,822,358
11,166,563
11,360,639
11,336,420
*
.0046
.0018
11,327,423
11,357,480
11,348,016
11,331,828
11,228,276
4,381,050
1.1384
1.1358
3,243,53tf
.0140
.0119
11,187,203
1 1,055,376
10,859,347
10,652,784
10,015,963
1.9144
1.9096
2,448,014
.0440
.0417
10,379,284
IO'2Ii'ol4
10,996,882
9,874,995
9i705,798
d not be raised aftd
sure was attained.
100 pounds.
2,308 (metric, 5,083).
i!
9,378,526
9,179,045
8,897,912
7,970,978
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIII.— Continued.
469
BAR NO. 74.
COMPOSITION.— Original mixture : Cu, 67.5 ; Sn, 5 ; Zn, 27.3.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
&
600
10
60?
640
680
720
760
800
10
^
840
880
Inch.
.0016
.0033
.0070
.0146
.0218
.0294
•0393
.0562
.0642
.0727
.0809
.0807
.0886
.0963
• I°37
.1107
.1180
.1177
• 1255
.13^5
• 1379
.1442
.1508
.iSH
38
Inch.
Pounds.
92°
960
1,000
IO
3
1,000
1,040
1, 080
I,I2O
1,160
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,560
1, 600
10
3
1,600
1,640
1. 660
Breaking
Modulus
1
Inch.
.1721
.1801
.1888
.2083
.2211
•2333
.2469
[2498
.2632
.2791
.3013
•3183
.3360
.'3396
•3521
•3727
.4013
.4301
.4620
:462;
.4874
Broke,
load, P=it
of rupture,
'-£-*
Inch.
.0083
.0068
14,871,767
1 4,794,9^*4
14,701,230
0025
0009
0028
0013
16,821,775
1 7,390,724
15,208,723
15,278,489
15,105,267
14,125,146
'.'...'.
14,578,869
14,390,973
13,820,378
13,828,573
13.834,729
13,712,725
13.723.572
.0190
.0175
13,490,121
12,159,913
0039
0024
13,783,981
13,834,726
13,918,109
14,040,945
14,113,185
.0521
•0503
10,513,107
0044
0032
14,154,417
14,352,805
14,491,853
14,628,641
14,724,630
.1167
.1151
9,610,361
660 pounds.
5,976 (metric, 3,935).
14,784,385
14,857,187
BAR NO. 76.
COMPOSITION. — Original mixture : Cu, 80 ; Sn, 12.5 ; Zn, 7.5.
120
160
200
10
3
200
240
280
.0053
.0109
.0193
.0271
.0361
.0463
.0468
.0546
.0614
.0682
0040
00l6
9,996,o6l
9,720,941
10,980,131
11,729,695
11,740,527
II,442,576
11,643,764
12,079,930
12,429,120
360
400
10
3
400
440
480
520
.0824
.0897
.0964
.1031
.1101
.1166
0046
0022
0057
0035
12,714,988
12,827,876
12,993,767
13,189,824
i3,36o,397
13,473,348
13,630,993
Left under strain.
Resistance increased in i hour to 6 pounds.
470 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIII. (Bar No. 76).— Continued.
LOAD.
i
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
720
760
800
10
84?
880
920
960
1,000
10
3
1,000
1,040
,080
,120
,160
,200
10
3
,200
,240
,280
1,320
1,360
I,4OO
10
Inch.
.1167
.1232
.1301
.1366
.1440
.1506
.1506
•1587
.1675
.1767
.1860
•1954
.1976
.2064
.2173
.2299
•2434
•2594
[2646
.2766
. 2926
.3126
.3313
.3529
Inch.
.0031
Pounds.
3
1,400
1,440
1,480
1,520
1,560
i, 600
10
1,600
1,640
i, 680
1,720
1,760
1,800
10
i, 800
1,840
1,880
1,920
1,960
2,000
IO
Broke wl
had ret
Breaking
Modulus
,
Inch.
•3791
.4036
•5163
.5364
.5706
.5986
•6559
.6990
^148
•7579
•7965
.8485
.9090
.9652
lile putting
iched 1,950 p<
load, P=2,
of rupture,
-&-
Inch.
.0964
.0081
.0064
13,760,813
13,845,426
13,962,296
13,980,603
14,071,480
.2011
.1983
8,209,046
.0182
.0156
14,020,942
13,950,222
13,791,965
13,671,035
13,347,452
.3462
.3425
6,821,346
.-5473
strain on anc
>unds.
ooo pounds.
5,073 (metric,
5,508,330
.0447
.0428
12,254,229
before it
4,645).
.0991
10,508,678
BAR NO. 77.
COMPOSITION.— Original mixture : Cu, 82.5 ; Sn, 15 ; Zn, 25.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
IO
3
400
440
480
520
560
.0012
.0031
.0071
.0154
•0235
.0307
.0421
.0422
.0498
•0575
.0655
.0732
.0800
.0802
.0874
.0950
.1017
.1090
600
10
^
640
680
720
760
800
IO
Left und
Resistan<
H
IO
800
840
880
920
960
1,000
IO
3
• "55
. 1161
.1217
.1286
.1361
• I437
.1506
2r strain.
:e increased i
.0046
.1463
• 1562
.1627
.1691
.1775
• 1857
0027
0014
0046
i 27 hrs. 50 n
i3,774,45i
.0021
.0006
17,107,474
14,938,924
I3,774,85i
i3,54o,38i
13,819,719
12,596,953
I31944,63<>
14,021,209
14,027,877
14,024,081
14,085,034
i to 14 Ibs.
.0025
.OOI2
12,779,076
12,912,424
12,954,669
13,040,943
13,258,292
0043
0027
0125
0105
14,259,881
14,342,099
14,425,528
I4,34i,363
14,279,259
••'••
13,349,313
13.396,852
13,558,134
13,623,198
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIIT.(Bar No. 77).— Continued.
471
LOAD.
o
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
1,000
1,040
i, 080
1,120
1,160
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
IO
3
1,400
::£
1,52°
1,560
1, 600
10
1, 600
Inch.
.1862
.1940
.2049
.2165
.2310
.2447
2473
.2615
.2791
.2992
•3174
•3390
• 343°
•3599
.3860
.4150
.4472
.4823
.4929
Inch.
Pounds.
,640
,680
,720
,760
,800
10
,800
&
,920
1,900
2,000
10
3
2,000
2,040
2,080
2,000
Breaking
Modulus
Inches.
.5167
.5847
.6287
.6807
.6950
•7356
.7842
.8311
.8924
•Q558
.9762
1.0197
1.0895
Broke
load,P=2,
of rupture,
'-£-
Inch.
.0311
.0275
14,215,075
13,003,632
'***£
•3156
7,011,877
.0822
.0800
10,823,095
•53°5
•5247
5,548,564
390 pounds.
9,045 (metric, 4,854).
.1730
•1705
8,607,535
BAR NO. 78
COMPOSITION.— Original mixture : Cu, 60; Sn, 2.5; Zn, 37.5.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
560
600
IO
600
640
.0014
.0079
.0119
.0197
.0284
•0357
.0431
.0446
.0513
.0600
.0683
.0756
.0839
.0840
.0917
.0996
.1079
.1158
•1235
'1239
1319
680
720
760
800
10
800
840
880
Q20
960
1,000
10
3
1,000
1,040
1, 080
.1307
.1489
.1581
.1676
!i683
• 1785
.1887
.2010
.2137
.2256
.2244
.2426
• 2595
.2791
.2998
.3244
•3245
•34i9
.3676
:r strain,
e decreased
:e decreased
.0083
.0070
13,698,602
13,608,229
13,528,371
I3,432,2io
.0019
.0001
7,124,701
9,459,685
11,428,458
11,891,227
I2,6l2,9l8
13,059,198
13,243,564
13,124,254
.0013
.0002
I3,l66,II2
13,133,199
i3,J85i394
13,401,225
I3»4I7»I97
.0215
.0201
12,474,544
,160
,200
10
3
,200
,240
,280
Left und<
Resistanc
Resistan<
.0032
.0012
13,503,526
13,562,685
13,562,685
13,609,517
13,672,506
'3,655,229
!o566
.0546
10,410,323
in 2 min. to i
in 4 min. to :
,265 Ibs.
,260 Ibs.
4/2 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE LXXXIII. (Bar No. I*}.— Continued.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
Resistanc
Resistanc
Resistanc
Resistanc
1,260
1,270
1,280
1,290
1,300
1,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,560
1,600
10
1,600
Inch.
e decreased i
e decreased i
e decreased i
i decreased i
.3699
• 3718
• 3741
.3762
.3788
• 3852
•43"
.4760
•4775
• 5OI7
• 543O
.7044
.7064
Inch.
n 7 min. to
n 22 min. to
n 4 h. 5201. t
1 12 h. 32 m.
1,257} IDS.
1,253* IDS.
D 1,245} IDS.
to 1,244 IDS.
Pounds.
1,640
1, 680
1,720
1,760
1, 800
10
1, 800
1,840
1, 880
1,920
1,960
2,000
10
3
2,000
2,030
Breaking
Modulus
I
Inches.
• 7345
•7979
.8654
.9268
1.0156
.0181
.0456
"1
.3206
.4426
1-4574
Broke in th
load, P = z
of rupture,
< = £ = <
Inch.
•5333
.5306
4,987,853
.1381
.1360
8,277,226
!882i
.8800
•
3,901,644
::::"::
e middle.
030 pounds.
9,508 (metric, 4,886).
.2942
.2921
6,392,409
BAR NO. 80.
COMPOSITION.— Original mixture : Cu, 77.5 ; Sn, 10; Zn, 12.5.
3
10
20
40
80
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
560
600
10
^
640
680
Left unde
Resistanc
.0014
.0083
.0111
.0208
.0290
.0368
.0448
.0449
.0523
•°^5
.0661
.0740
.0814
.0810
.0884
•0955
.1025
.1095
.1165
iiios
• 1235
• 1304
r strain.
z decreased i
680
£
800
10
8ci
840
880
920
960
I,OOO
10
3
1,000
1,040
,080
.120
,160
,200
10
3
,200
,240
,280
,320
,360
,400
IO
3
1,400
.1315
.1364
.1445
-ISIS
.1524
.1601
.1690
.1809
• T959
.2099
.2130
.225!
.2419
.2613
.2824
.3023
'3086
•3249
•3445
.3765
.4039
• 4475
.4W?
.0019
.0005
6,332,141
10,107,072
10,873,815
",425,387
11,731,423
.0104
.0085
13,871,289
13,821,159
13,876,377
.0297
.0279
I3,787,53<5
I3,683,42I
13,364,351
12,519,481
.0024
.0010
.0045
.0029
n 43 min. to
12,058,914
12,577,687
12,721,759
12,784,079
12,913,211
13,079,741
13,207,981
i3,33M72
J3,439,i73
13,533.934
T3,6i7,95o
13,703,452
672 pounds.
.0770
.0752
10,431,381
• • • •
.1776
.1747
8,221,178
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIII. (Bar No. 80).— Continued.
473
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Pounds.
1,440
1,480
1,520
1,560
1,600
10
3
i, 600
1,640
i, 680
1,720
1,760
i, 800
Inch.
.4880
.5215
•5710
.6148
.6675
!o76o
.7096
|P
Inch.
Pounds.
10
i, 800
1,840
i, 880
1,920
1,960
Breaking
Modulus
R
Inches.
• 9777
1.0177
1.0903
i . 1930
Broke just
load, P = i
of rupture,
= 55T« = 63
Inch.
.5756
.57i8
^3435
• 3410
6,293,140
if ter beam rose.
,960 pounds.
,849 (metric, 4,489).
4,912,868
BAR NO. 87.
COMPOSITION.— Original mixture : Cu, 77.5 ; Sn, 12.5 ; Zn, 10.
3
10
20
4°
80
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
&
10
^
640
680
720
760
800
IO
hi
840
880
920
960
It ,000
IO
.0018
.0063
.0108
.0185
.0263
.0336
•0415
.0427
.0520
.0603
.0675
.0743
.0816
.0817
.0887
.0958
.1025
.1089
• "53
liiei
.1219
.1284
.1348
.1413
.1485
• 1493
•1557
.1630
.1707
•1794
.1897
3
1,000
1,040
1, 080
1,120
1,160
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,560
1, 600
IO
1, 600
1,640
1, 680
I,72C
i,76c
i,8oc
10
1,800
1,825
Breaking
Modulus
l
.1912
.2004
.2113
.2225
• 2377
.2570
.2592
.2705
.2845
.3029
.3240
•3493
•3553
• .3690
.3905
•4134
• 4597
• 4950
-5°43
• 5225
.5513
6008
.6490
.6885
.7050
Broke,
load, P= i,
of rupture,
P 3^ *
? = 2^ = 6
.OI06
.0021
.0006
8,550,829
9,975,965
11,647,614
12,289,782
12,826,242
12,980,775
.0380
.0348
12,576,762
•0035
.0018
12,431,587
12,507,172
12,769,235
12,050,657
13,203,483
.0912
.0892
10,795,632
.0043
.0021
• 0055
.0038
J3i36i,27i
13,495,668
13,664,637
13,850,926
14,016,565
14,141,485
14,264,731
14,386,704
14,486,388
14,510,495
'
liSos
.1830
8,706,298
^288
.3245
825 pounds.
1,705 (metric
7,041,858
, 4,538).
14,531,465
14,54^654
14,516,869
14,413.435
0119
474 MATERIALS OF ENGINEERING— N OX-FERROUS METALS.
TABLE LXXXIII.— Continued
BAR NO. 88.
COMPOSITION.— Original mixture : Cu, 82.5 ; Sn, 12.5 ; Zn, 5.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
fe .•
o £
ll
S, w
Pounds.
3
10
20
e
120
160
200
10
3
200
240
280
320
360
400
10
3
400
440
480
520
560
600
10
600
640
680
720
760
800
10
80?
840
880
920
960
1,000
IO
3
1,000
1,040
1, 080
1,120
1,160
I,2OO
Inch.
.0020
.0047
.0090
.0075
.0254
.0338
.0410
.0411
.0509
.0590
.0666
.0739
.0810
'.oBi6
.0888
.0958
.1021
.1097
.1171
.1169
.1231
.1310
.1373
• I45I
.1528
.1534
.1608
.1693
.1783
.1880
.1983
. io88
.2090
.2206
.2341
.2502
.2675
Inch.
Pounds.
IO
3
,200
,240
,280
'320
,360
1,400
IO
3
1,400
1,440
1,480
1,520
1,560
1,600
10
1,600
1,640
i, 680
1,720
1,760
i, 800
10
Left und
Resistan<
IO
,,80!
1.840
1, 880
1,920
1,960
•2 JOO
10
3
2,000
2,040
2,o8o
2,120
Broke ju
Breaking
Modulus
Inch.
.2726
.2864
'3258
• 3487
• 3730
^3825
.4017
.4326
• 4733
.5062
• 5520
.'5649
.5875
.6242
.6828
.7412
.8048
er strain.
:e increased
IsioS
.8490
.9086
.9788
.0530
.1326
• T576
.2980
.6100
st after beam
' load,/>^ 2,
of rupture,
«-£-
Inch.
.0520
.0494
.0023
.0003
.0038
,0017
11,327,661
11,831,112
12,169,145
12,576,378
12,601,287
12,985,365
."53
.1124
9,991,423
12,551,671
12,790,394
12,967,797
13,145,680
.2431
• 2399
7,715,943
.0050
.0039
.0098
.0075
13,190,091
13,377,788
I3,557,69I
13,589,062
13,639,627
:438o
.4328
in i hour to
.4306
.4287
5,953,778
• 13,839,806
13,818,016
13,959,508 ;
13,942,939 •
13,937,173
23 pounds.
.0215
.OT94
I3,9°5,974
13,836,741
I3,735,5°3
13,593,199
13,424,108
.7059
.7014
4,700,689
i rose.
120 pounds.
9,960 (metric, 4,918).
10,791,095
STRENGTH OF COPPER ALLOYS.
TABLE LXXXIIL— Continued.
BAR NO. 89.
COMPOSITION.— Original mixture : Cu, 85 ; Sn, 12.5 ; Zn, 2.5.
475
LOAD.
Pounds.
3
10
20
g
120
!6o
200
10
3
200
240
280
32*
360
400
10
3
400
440
480
5£
560
600
10
6d
%
720
760
800
10
Sol
840
880
92O
960
1,000
10
3
1,000
• 1,040
2
o
Q
SET.
MODULUS OF
ELASTICITY.
LOAD.
DEFLECTION.
SET.
MODULUS OF
ELASTICITY.
Inch.
.0021
.0067
.0112
.0207
.0292
.0367
.0444
.0450
•0536
.0620
.0694
.0765
.0840
!o844
.0915
.0981
.i°53
.1131
.1208
Inch.
Pounds.
i, 080
1,120
1,160
1,200
10
3
1,200
1,240
1,280
1,320
1,360
1,400
10
3
1,400
1,440
1,480
1,520
1,560
i, 600
10
3
i, 600
1,640
1,680
1,720
1,740
1,760
1,780
i, 800
1,820
1,840
i, 860
1,880
1,900
1,920
The bear
crease
Breaking
Modulus
1
Inches.
.2647
.2880
.3193
.3505
Inch.
.0031
.0010
7,877,604
9,424,989
10,199,024
10,845,190
11,505,164
11,886,372
.1245
.1214
9,035,081
.3625
•3993
• 4435
.5130
•5783
.6527
•0053
.0031
11,816,403
11,918,049
12,168,285
12,419,811
12,566,652
.3707
•3671
5,660,48!
•6743
.7230
.8345
.9425
.0777
.2199
• 2255
:f$
•6595
.7065
.8645
.9655
•0745
.1805
• 2995
•4075
• 5425
.6985
.8285
n could not
of load,
load, P- i,
of rupture,
f-^ = 6
zbd*
.0084
.0049
12,690,260
12,915,497
13.007,377
13,066,650
13,107,604
:8472
.8423
3,461,264
.1279
.1352
.1427
.1504
.1594
!i6o6
.1692
.1798
.1930
.2095
.2265
.2307
.2460
.0172
.0143
13,205,304
13,273,061
I3,3i5,i59
13.335,359
13,244,652
2,257,161
13,101,403
be raised with an in-
520 pounds.
2,405 (metric, 4,387).
.'0438
.0410
11,651,201
CHAPTER XIII.
CONDITIONS AFFECTING STRENGTH OF NON-FERROUS
METALS AND ALLOYS.
268. The Conditions Affecting the Strength of the Non-
Ferrous Metals are precisely such as have been found to
modify the valuable properties of iron and steel, and of other
materials of construction used by the engineer. The effect
of every change, whether chemical or physical, of internal or
of external conditions, affecting the metal is seen in a modifi-
cation of its strength, elasticity, ductility and resilience.
Change of temperature, either gradual or sudden, alteration
of methods of manufacture, differences, however slight, of
composition and of density, and every variation of the mag-
nitude, and of the number of applications, of the load has an
effect, more or less marked and important, upon the value and
reliability of the metal as a structural material.
The effect of heat and of variation of temperature upon
the non-ferrous metals and upon the alloys has been but
little studied ; but some important facts have become well
ascertained.
269. The Strength of Copper is modified by tempera-
ture in the same general way as iron (Part II., Arts. 285-288).
It is reduced steadily, and according to a simple law, as tem-
perature rises, finally becoming zero at the point of fusion.
Decrease of temperature causes increase of strength.
A committee of the Franklin Institute, of the State of
Pennsylvania, consisting of Professor W. R. Johnson, Benja-
min Reeves, and Professor A. D. Bache, were engaged, during
a period extending from April, 1832, to January, 1837, in
experiments upon the tenacity of iron and of copper, under
the varying conditions of ordinary use.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 477
The effect of change of temperature upon those metals
was investigated with equal intelligence and thoroughness,
and most valuable results were obtained.
Upward of one hundred experiments upon copper, at
temperatures ranging from the freezing point up to 1,000°
Fahrenheit, exhibited plainly the fact that a gradual diminu-
tion of strength occurs with increase of temperature, and vice
versa, and that the change is as uniform as the unavoidable
irregularities in the structure of the metal would allow.
The law of this variation of tenacity, within the limits
between which the experiments were made, was found to be
closely represented by the formula,
D* = C T\
i. e., the squares of the diminutions of tenacity vary as the
cubes of the observed temperatures measured from the freez-
ing point.
The following are the tenacities of copper at various
temperatures, as determined by experiment, to the nearest
round numbers (see Appendix) :
TABLE LXXXIV.
TENACITIES OF COPPER WITH VARYING TEMPERATURES.
TEMPERATURE.
TENACITY.
TEMPERATURE.
TENACITY.
F.
c
Lbs. per
Kilogs. per
C.
Lbs. per
Kilogs. pel
sq. in.
sq. cm. ;
sq. in.
sq. cm.
122°
50°
33,000
231 602°
316°
22,000
212
100
32,000
225 801
427
19,000
144
302
150
31,000
218
9I2
490
15,000
105
482
250
27,000
190 i 016
546
11,000
77
545
290
25,000
176 2,032
I, III
0
0
270. The Effect of Heat on Bronze and the kalchoid al-
loys of copper, tin and zinc was determined by the British
Admiralty at Portsmouth in the year 1877.*
* London Engineering, Oct. 5, 1877.
4/8 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The metal was cast in the form of rods one Inch in
diameter, and composed of five different alloys as follows :
No. i. Copper, 87.75 '• tin 9.75; zinc, 2.5.
No. 2. Copper, 91 ; tin, 7 zinc, 2.
No. 3. Copper, 85 ; tin, 5 zinc, 10.
No. 4. Copper, 83 ; tin, 2 zinc, 15.
No. 5. Copper, 92.5 ; tin, 5 ; zinc, 2.5.
The specimens were heated in an oil bath near the test-
ing machine, and the operation of fixing and breaking was
rapidly and carefully performed, so as to prevent, as far as
possible, loss of heat by radiation. The strength and ductility
of the above test-pieces, at atmospheric temperature, were as
follows: No. I, 535 pounds, 12.5 percent.; No. 2, 825 pounds,
1 6 per cent.; No. 3, 525 pounds, 21 per cent.; No. 4, 485
pounds, 26 per cent, and No. 5, 560 pounds, 20 per cent. As
the heat increases a gradual loss in strength and ductility
occurs, up to a certain temperature, at which, within a few
degrees, a great change takes place, the strength falls to
about one half the original, and the ductility is wholly gone.
Thus in alloy No. I, at 400° F. (204° C.) the tensile strength
had fallen to 245 Ibs., and the ductility to 0.75 per cent. ; the
precise temperature at which the change took place was
ascertained to be about 370° F. (188° C.). At 350° F. (177°
C.), the tensile strength was 450 Ibs., and ductility 8.25 per
cent. At temperatures above the point where this change
begins and up to 500° F. (260° C.) there is little if any loss of
strength.
Phosphor-bronze was less affected by heat, and at 500° F.
(260° C.) retained two-thirds its tenacity and one-third its
ductility. Muntz metal (copper, 62 ; zinc, 38) was found
reliable up to the limit, and iron and steel were not injured.
The following table exhibits the results of these expert
ments in convenient shape.
Bach finds bronze sensitive to change of temperature, in
some cases losing 6 per cent, tenacity at 400° F. and 50 per
cent, at 600°. The alloy Cu. 91, Sn. 5, Zn. 4, useful with low
steam-pressures, is not probably reliable with high pressure
or superheat.
CONDITIONS AFFECTING STRENGTH OF ALLO VS. 4/9
X! >•
X! £
§ 5
< o
fr* *
< a
&sg
K O «
g^5|
W N « S
N"S
UN
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UHN
s. ;
6=t
s 4'
O '
hN
UHs)
•31JSU3X
•911SU3X
311SU3X
•3HSU3X
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•3USU3X
M '8
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8 * S
5 8 S S 2 2
III &8S.8&8&8
•S^M HN N COCOTfrflO
a
480 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
271. Various Metals. — Variations of temperature, accord-
ing to Baudrimont,* produce alterations of the tenacity of
metals, as below. The metals were in the form of wire,
nearly 0.4 millimetre (0.0158 inch) in diameter, except the
iron, which was 0.175 mm. (0.0067 inch), and the copper,
0.48 mm. (0.0189 inch). The tenacity is reduced to kilo-
grammes per square centimetre. All, except iron, are weak-
ened by increase of temperature.
TABLE LXXXVI.
TENACITIES OF METALS AT VARYING TEMPERATURES.
TENACITY IN KILOGS. PER SQ. CM.
o° C. (32° F.)
100° C. (212° F.)
200° C. (392° F.)
Gold
1,840
2,263
2,510
2,832
3,648
20,540
1,522
1,928
2,187
2,327
3,248
19,173
1,288
1,728
1,822
1,858
2,708
21,027
CoDoer .
Silver
Palladium
Iron
272. The Modulus of Elasticity of hard-drawn iron, cop-
pen and brass wires was found by Loomis and Kohlrausch f
to vary with temperature according to a law expressed by
the equation
in which E is the modulus at the temperature t, E0 that at o°
and a and b experimentally determined co-efficients ; for the
Centigrade scale, their values are
a
b
Iron .. . ..
o 000483
O OOOOOO 12
O OOO ^72
o.ooo ooo 28
Brass ....
o. ooo 48^
o ooo ooi 36
* Annales de Chimie et de Physique, 1850.
f Am. Jour. Science and Arts, vol. 1., Nov., 1870.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 481
Thus, the reduction of the value of the modulus between
the melting point of ice and the boiling point of water is, for
iron 4.6 to 5 per cent.; for copper, 5.5 to 6 per cent.; for brass,
5.6 to 6.2 per cent., and this variation is most rapid at the
highest temperature. The values of the moduli were found
to be very closely proportional to the co-efficients of expansion.
The following determinations were made by Wertheim :
TABLE LXXXVII.
VARIATION OF MODULI OF ELASTICITY WITH TEMPERATURE.
S. G.
15° C.
, 59° F.
IOO° C.
*
, 212° F.
200° C
., 392° F.
Metric.
British.
Metric.
British.
Metric.
British.
Lead
n 232
17-7
2.4
163
2 3
Gold
1 8 03^
«8
7 O
COT
7 6
S4.8
7Q
Silver
IO. 3O4.
71 =
IO 2
727
IO 4.
637
9T
Palladium . . .
ii 225
Q7Q
14. O
Copper. . .
8.036
I O^2
ic o
OS1}
14.. O
786
II 2
Platinum
v- VJW
21 083
I £.^2
22 2
I 4.18
2O 3
I 206
18 e.
Steel (wire)
7 622
I 728
24 Q
2 I2O
•JO A
I 028
1.0. 5
27 C.
Steel (cast) . . .
7.QIQ
I 0^6
26 e,
I QOI
27 I
I 7Q2
2<; 6
Iron
7. 7^7
2.O7Q
26.8
2 188
31 2
I.77O
2C 2
The metric values are in thousands of kilogrammes per
square centimetre ; the British in millions of pounds per
square inch.
273. The Stress produced by Change of Temperature
is easily calculated when the modulus of elasticity and the
coefficient of expansion are known, thus :
Let E = the modulus of elasticity;
A = the change of length per degree and per unit of
length ;
Jt° = the difference of initial and final temperatures;
p = the stress produced.
31
482 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Then:
/ : E : : A Af : i,
/./ = \EAf (i)
For good wrought iron and steel, taking E as 28,000,000
pounds on the square inch, or 2,000,000 kilogrammes on the
square centimetre, and A as o. 0000068 for Fahrenheit, and as
0.0000120 for Centigrade degrees :
p = 190 Af Fahr., nearly }
= 25 Af Cent., nearly f "
• • . (2)
For cast iron, taking E = 16.000,000 ; A, = 0.0000062 :
/ = 100 At0 Fahr., nearly ) . .
= 12 At0 Cent., nearly \ •••••; U)
This force must be allowed for as if a part of the tension,
7", or compression, C, produced by the working load when
the parts are not free to expand.
274. Sudden Variation of Temperature has an effect,
very usually, upon the non-ferrous metals, which is afterward
seen in a permanent alteration of their properties. Repeated
heating and cooling causes a permanent change of form, and
sudden cooling from high temperatures causes a modification
of the tenacity and ductility of the kalchoids and the metals
composing such alloys, which is precisely the opposite of that
produced on steel. Thus copper, brass, and bronze, suddenly
cooled from a low red heat, are softened and weakened and
greatly improved in malleability and ductility. This process,
which is one of hardening and tempering with steels, is thus
one of softening with other metals. On the other hand, very
slow cooling softens or " anneals " steels, while it hardens the
non-ferrous metals and alloys. Thus, also, casting bronze ord-
nance or other castings in chills increases the value of the
metal by preventing liquation and securing homogeneousness
and maximum density.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 483
275. The Effect of Chill-casting is exhibited in the fol-
lowing tables of tests by tension furnished to the Author by
the U. S. N. Department in the course of a series of investi-
gations in 1877. The metal has the composition, copper (Lake
Superior), 9 ; tin, I ; it was cast either in chills or in sand as
specified, after having been melted in a reverberatory furnace,
the copper first and the tin three hours later. The specimens
tested were of the." short " pattern, and the reduction of sec-
tion, rather than the elongation recorded, is the measure of
relative ductility. The tables also exhibit the method of
testing usual in the Ordnance Department of the U. S. Navy
in 1875-6. British measures are here used.
TABLE LXXXVIII.
EFFECT OF CASTING BRONZE IN "CHILLS.1
Navy Ordnance- Bronze.
TENSILE
<£ .
D "" <
STRENGTH PER
z ^ o
§ < "
>
SQUARE INCH OF—
"23
BJj|
I
MARK.
~
•0
h j
tk, g
K
O
ii
3.2
z " 2
< ^ o
I°H
U
C
JfS
rt ^
S o 2
S2^
U
'C ^
*•* on
^ H O
S P *
0*
fe
S
u
E
cu
M i, 3-4-75
42,037
70,000
•4795
.40
41,768
71,600
.478
.417
BB 'iX '.'.'. .'..
22,385
.100
Full of large tin spots.
M2, 5-6^75
No. 3, 8-21-75 .
No. 2, 8-21-75 .
45,737
49,772
48,000
65,600
6o,OOO
.522
.2603
.211
•47°
.240
.20
8 878
Cast in chill mould.
Cast in chill mould.
GB 2, 5-6-75 . .
G 63,5-6-75 •-
B 3 L, 12-70-7 5
35,820
29,818
33,630
39,000
•4075
.0291
•50
.134
392
Flaw in the breaking portion*
Cast in chill mould.
M i C, 3-11-76
B 2 C, 3-11-76.
B 3 C, 3-11-76.
5i,459
45,837
44,869
91,600
73,450
71,600
!s8o
.396
.4x5
.438
.376
•373
8 853
Cast in chill mould.
Cast in chill mould.
The guns cast in chill moulds were composed of 10 parts
of copper to I part of tin ; the others were of 9 parts of cop-
per to I part of tin.
In the course of experiments made by Major Wade,* three
* Report on Ordnance.
484 MATERIALS OF ENGINEERING— XOX-FERROUS METALS.
howitzers, Nos. 27, 28, and 29, were cast from the same liquid
metal. No. 27 was cast when the metal was at the highest
temperature, No. 28 was cast fifteen minutes later, and No.
29 fourteen minutes after No. 28. The following results were
obtained:
Z
h
«2
SPECIFIC GRAVITY —
TENACITY —
ll
H ^j
Of small bars cast
Of small bars cast
S
< ,,
in —
m —
2
TIME OF
LADLE,
K <
Of gun-
heads.
Of entire
gun.
Of gun-
heads.
Gun
mould.
Separate
mould.
Gun
mould.
Separate
mould.
27
0
Highest . . .
7.986
8.195
8.686
8-554
17,761
50,973
31,1:32
28
29
15
29
Mean
Lowest ....
8.351
8.538
8.551
8.752
8.823
8.816
8.447
8.376
28,995
23,722
56,786
28,153
28,082
In casting another howitzer, No. 30, small test-bars were
cast in separate moulds, one of which was of cast iron, to
ascertain the effect of sudden cooling, and the others were of
clay, similar to the gun-mould. The tests of all the samples
from this casting were as follows :
SPECIFIC GRAVITY.
TENACITY.
Small bars cast separately in iron mould . .
Small bars cast separately in clay mould . .
Small bar cast in gun mould
8-953
8.313
8.806
37,688
25,783
C7.7Q8
Gun-head samples
8 J.QO
qe .1:78
8.7^
The effect of the chill is evidently very beneficial, and iron
moulds should, therefore, always be used where possible in
the casting of bronze ; with brass they are less necessary.
276. Effect of Tempering and Annealing. — Riche de-
termined the effect of tempering and annealing upon the
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 485
density of the bronzes, finding that tempering increased the
density of those rich in tin but not of others, as gun-bronzes ;
and that annealing reduces the density of tempered bronze
although it does not entirely destroy that effect. Density is
increased to a considerable degree by mechanical action as
well as by tempering.
Successive temperings and annealings produce, on the
whole, an increase of density. Tempering, according to both
Darcet and Riche, softens the bronzes rich in tin, t.e.t those
containing about 20 per cent. tin. Thus, Riche obtained the
result that such bronzes, tempered, can be moulded in the
press, while they will crack if untempered or annealed.
Bronze and steel exhibit opposite behavior in this respect.
The same author finds that working hot does not increase
the density more than working at low temperature. The
metal increases in density very rapidly by working hot,
and without danger of rupture ; while cold the action is ex-
tremely slight and very difficult.
There is evidence that the method of making gongs by
the Chinese involves working hot under the hammer.*
Riche, reaches the following conclusions : f
"The bronzes rich in tin (18 to 22 per cent.) increase in
density with tempering ; and annealing lessens the density of
tempered bronze, but in a less proportion, The density is
considerably increased by the alternate action of tempering
and annealing, and of the press. These effects, tne reverse
of those in steel, coincide with the fact that tempering softens
bronze while it hardens steel.
" This softening, discovered by Darcet, is not sufficient
to allow of this bronze being worked cold for industrial pur-
poses. It was shown that this metal — extremely hard when
cold and pulverizable at red heat — is forged and rolled at
dark red heat with remarkable facility. This fact enabled
me, in common with M. Champion, to succeed in the manu-
facture of tamtams, and other sonorous instruments, by the
method followed in the East.
* Industries Anciennes, etc. Lacroix, Paris, 1869.
f Annales de Chimie et de Physique, vol. xxx., 1873.
486 MATERIALS OF ENGINEERING— NON-FERROUS METAL*.
" Tempering produced no apparent softening in the
bronzes less rich in tin (12 to 6 per cent.); and if they are
tempered for industrial uses it is more especially in order to
detach the oxide produced during the reheating of the matter
in the course of the operations.
" It was found that in the axis of a cannon, and especially
toward the muzzle, there are some parts very rich in tin and
in zinc.
" The density of copper, subjected alternately to me-
chanical action, then to tempering or annealing, displays in-
verse variations according as it is exposed to the air or
sheltered from it during the reheating ; while in the first case
the mechanical action increases the density, in the second
mechanical action diminishes the density.
" Mechanical action increases the density of yellow brass,
and this effect is counteracted in part by tempering, and
especially by annealing. It is thought that annealing is pref-
erable to tempering in working with brass.
" Mechanical action, tempering, and annealing, do not
sensibly change the volume of similor and of the bronzes of
aluminium, alloys remarkable for the facility with which they
can be worked.
" While repeated mechanical action increases the density
of the bronzes rich in tin, especially of porous copper, of
copper alloyed with iron, of brass, it evidently diminishes the
density of copper exposed to the air during reheating, and it
produces no noticeable alteration in the volume of similor or
of aluminium bronze. Tempering produces on brass, and
especially on the bronzes rich in tin previously annealed, an
increase in density, contrary to what takes place in steel, cop-
per and glass.
" It will be perceived that tempering diminishes the
density of a body, because the surface, cooled before the
centre, cannot contract freely by reason of the resistance
that the interior parts dilated at this moment offer to con-
traction."
The following are some of the results of Riche's experi-
ments.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 487
BRASS.
DENSITY.
I.
II.
After rolling
8.409
8-410
8.414
8.431
8-443
8 433
8 439
8-437
8-439
8.445
8.412
8.411
8.415
8.427
8.436
8.436
8.444
8-437
8-437
8.443
After rolling:. •
The metal was a yellow brass containing copper, 65 ; zinc,
35. The same general effect was seen when the brass con-
tained, copper, 9.1 ; zinc, 9.
It is to be noted that there is a great difference between
the effect on copper protected from the air while heating it,
as should always be done, and on copper exposed to the air ;
annealing and tempering diminished density in the one case
and increased it in the other, although the latter modification
is not important. The increase of density resulting from the
heat is very nearly compensated by the tempering, so that
the plate, after being made considerably thinner, is found to
have the same density as before the operation. Cast at a
high temperature, the density became 8.939, in Riche's ex-
periments, and was but 8.039 when poured at a low heat.
277. The Effect of Annealing on Tenacity is seen in
the following experiments :
Wertheim obtained for the tenacity of copper wire,
T.
Tm.
ELON.
58,600
4, loo
O.OO33
" annealed . . ...
AC IOO
•7,160
o 0030
488 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Kirkaldy, testing wire, obtained the following results :
TABLE LXXXIX.
TENACITY OF WIRE, HARD AND ANNEALED.
HARD WIRE (A).
ANNEALED WIRE (B).
COMPLETE TURNS
IN 5 IN. (12.8
CM.).
FINAL ELONGA- I
TION PER CENT.
Lbs. per
sq. in.
Kilogs.
persq. cm.
Lbs. per
sq. in.
Kilogs.
per sq. cm.
A.
B.
Phosphor-bronze .
< <
< t
< (
102,750
120,957
120,950
139,141
159.515
I5I,H9
63,122
120,976
65,834
7,224
8,504
8,503
9,872
11,212
IO,625
4,438
8,506
4,629
49»35i
47,787
53,38i
54,153
58,853
64.569
37,002
74,637
465160
3-470
1,360
3,753
3,807
4,138
4,340
2,602
5,248
3,245
6.7
22.3
13-0
17-3
13-3
15.8
86.7
22.4
48.0
87
52
124
53 .
66
60
96
79
87
37-5
34-1
42.4
44.9
46.6
42.8
34-1
10.9
28.0
Steel
Best charcoal iron.
These figures are considerably in excess of those or-
dinarily obtained for bronzes into which no phosphorus has
been introduced. The effect of annealing is remarkably great.
Other illustrations of this and related phenomena are
given elsewhere, as, e.g., in Art. 247, where they are well ex-
hibited in Anderson's experiments on sterro-metal.
278. The Effect of Temperature of Casting and cool-
ing upon zinc has been studied by Bolley as illustrative of
this effect generally.* He finds that zinc may solidify in
either of two forms, the one finely crystalline, the other
coarsely crystalline with lamellar structure. He finds these
conditions to be determined, not by the presence of other
elements, but by the temperature of casting. When cast at
the lowest temperature at which it will "pour," it takes the
first form, with a density of 7.18; when cast at a full red
heat, it takes the second form, with a lower density, 6.86.
In the first case, it is comparatively malleable, remains malle-
able throughout a wide range of temperature, and is not as
readily soluble in acids as when in the second condition. In
* Annalen der Chimie und Pharm., xcv,, p. 294.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 489
the latter form it is not malleable, and is more soluble.
These conditions have not been studied with other metals.
279. The Effect of Time, and Velocity of Rupture, on
the action of stress is not less important with the non-
ferrous than with the ferrous metals. A very important
difference is found to exist between the two classes. (See
Part II., Art. 295, et seg.) The rupture of the non-ferrous
metals takes place under lower stresses, as the time of oper-
ation is greater, and the fracture is more slowly produced.
The contrary is the case with iron and steel. With non-ferrous
metals, the piece -strained may give way, ultimately, under
static loads greatly less than those required to produce im-
mediate rupture. This occurs to a less extent with soft
annealed iron, and still less with harder irons and steels.
Cast iron is stated by Hodgkinson to be capable of sustain-
ing, indefinitely, loads closely approaching the breaking load
under test. Some of the alloys will probably exhibit similar
differences.
With rapid distortion, the resistance is increased with
non-ferrous metals, decreased with iron.
The Author has, therefore, enunciated a principle which
had been deduced from experiments on wrought iron, which
is, evidently, of vital importance to the engineer, viz. : " That
the time during which applied stress acts is an important ele-
ment in determining its effects, not only as an element which
modifies the effect of the vis viva of the attacking mass and
the action of the inertia of the piece attacked, but also as
modifying seriously the conditions of production and relief
of internal strain by even simple stresses."*
Should it be true, as suggested by the Author, that the
cause of the variation of resistance, sometimes observed with
increased velocity of distortion, is closely related to the cause
of the variation of the elastic limit by strain, f it would seem
to be a corollary that materials so inelastic and so viscous as
to be incapable of becoming internally strained during dis-
tortion, should offer greater resistance to rapid than to
* Trans. American Society of Civil Engineers, vol. iv., p. 334.
+ See Part II., pp. 588-604 ; figures 135-138.
49° MATERIALS OF ENGINEERING— NON-FERROUS METALS.
slowly-produced distortion, in consequence of their inability
to " flow " so rapidly as to reduce resistance by such fluxion
at the higher speed, or by correspondingly reducing the
fractured section. This principle has been shown, by a large
number of experiments, to be frequently, if not invariably,
the fact. Copper, tin, and other inelastic and ductile metals
and alloys, were found by the author to exhibit this behavior,
and are therefore quite opposite in this respect to commercial
wrought iron and worked steel.
The records of the Mechanical Laboratory of Sibley Col-
lege, Cornell University, frequently illustrate the proposition
that metals which gradually yield under a constant load offer
increased resistance with increased rapidity of rupture.
The curves of deflections of a considerable number of
ductile metals and alloys are very smooth when the time dur-
ing which each load has been left upon them is the same ; but
whenever that time has been variable the curve has been
irregular. Bars of such metals broken by transverse stress
give a greater resistance to rapidly increasing stress than to
stress slowly intensified. Two pieces of tin, as described in
Article 280, were broken by tension, the one rapidly and
the other slowly. The first broke under a load of 2,100 and
the latter of 1,400 pounds. The example illustrates well the
very great difference which is possible in such cases, and
seems to the writer to indicate the possibility, in extreme
cases, of obtaining results which may be fatally deceptive
when the time of rupture is not noted.
The depression of the elastic limit has been observed pre-
viously in materials, but less attention has been paid to it than
the importance of the phenomenon would seem to demand.
The strain diagram of a bronze bar is nearly hyperbolic ;
but the law of Hooke, ut tensio sic vis, holds good, as usual, up
to a point at which the load is about one-half the maximum.
The curve of times and loads exhibits the rate of loss of effort
while the bar was finally held at a deflection of 0.5456 inch,
the load being carefully and regularly reduced, as the effort
diminished, from 1,233 to 911 pounds, at which latter figure
the bar broke. The curve is a very smooth one.
CONDITIONS AFFECTING STRENGTH OF ALLOYS.
TABLE XC.
EFFECT OF TIME ON BRASS.
BAR NO. 599.
90 parts zinc, 10 parts copper : i x 0.992 x 22 inches.
491
LOAD.
DEFLECTION.
SET.
LOAD.
DEFLECTION.
SET.
LOAD.
DEFLECTION.
SET.
Pounds,
23
*!
103
*43
163
Resistan
to 143
^
203
243
283
323
Inch.
0.0033
0.0078
0.0127
0.0225
0.031
ce fell in i
0-o347
0.0391
0.0471
0.0544
0.0611
0.0692
Inch.
5 h. 25 m.
o 0039
Pounds.
363
4°3
3
Resistar
to 333
3isis
to 302
303
403
Inch.
0.0781
0.0881
Inch.
Pounds.
£
803
1,003
1,103
1,203
1,233
Resisl
to 1,137
3
Inch.
Inch.
o 0336
n 15 m
o 2736
0.1641
0.2149
0.3178
0.3921
0.481
0.5209
ance fell i
0.5209
0.0079
0.0886
ce fell in £
0.0886
h. 30 m.
0.0246
n 15 h.
0.0896
tance fell
0.0896
0.0876
0.1072
0.1282
0.1521
1,233
0-5456
A.M., and the effort to restore itself measured
The bar was left under strain at u
at intervals, as follows :
HOUR. — 11:37 11:50 A.M. 12:2 12:8 12:25 12:39$ 12:53$ 12:58$ 1:20 P.M.
EFFORT.— 1,133 1,093 1,070 1,063 ^043 1,023 1,003 993 911 pounds.
At ih 23™ P.M. the bar broke.
BAR NO. 596.
75 parts zinc, 25 parts copper ; second casting • 0.985
0.985 x 22 inches.
fe
z°
£
o
o
£"j
H
H
LOAD.
w
SET.
LOAD.
H
SET.
LOAD.
U
w
SET.
w
jk
•
Q
Q
H
Q
Pounds.
Inch.
Inch
Pounds.
Inch.
Inch.
Pounds.
Inch.
Inch.
23
0.0057
463
0.0799
503
0.0894
. .
63
0.0142
503
0.0866
543
0.0952
103
0.0207
3
0.0014
583
O. IOI2
183
0.0275
0.0346
503 .
Rests
o!o866
tance fell
in s'h'.
£3
0.1042
0.1075
• •
223
0.0414
to 489
0.0866
643
0.1102
263
303
0.0485
0.0549
0.0610
489
Resistan
o!o866
ce fell in i
0.0074
3 h. 30 m.
663
Broke .
rmgii]
0.1136
; seconds
g sound.
after with
383
0.0669
to 473
0.0866
423
0.073
3
0.0092
An example of somewhat similar behavior, but exhibited
by a metal of very different quality, is shown above.
492 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
This bar was hard, brittle, and elastic, but must ap-
parently be classed with tin in its behavior under either con-
tinued or intermitted stress.
These latter specimens were broken ; one in each set by
adding weight steadily until the end of the test, so as to give
as little time for elevation of elastic limit as was possible \
and one in each set by intermittent stress, observing sets,
and the elevation of the elastic limit.
There seems to the Author to exist a distinction, illus-
trated in these cases, between that " flow " which is seen in
these metals, and that to which has been attributed the relief
of internal stress and the elevation of the elastic limit by
strain and with time.
If the long-known effects of cold-hammering, cold-rolling,
and wire-drawing in stiffening, strengthening, and hardening
some metals can be, as the Author is inclined to believe, at-
tributed in part to this molecular change, as well as to simple
condensation and closing up of cavities and pores, this vari-
ation of the elastic limit by distortion under externally ap-
plied force has been shown to occur in iron and in metals of
that class in tension, torsion, compression, and under trans-
verse strain.
280. Effect of Prolonged Stress on Tin and Zinc.— In
testing a bar of tin, in work done as described in earlier chap-
ters, the Author studied this phenomenon. An experiment
on No. 29 A (a bar of pure tin) was made to determine the
difference in resistance to slow and rapid rupture. This bar
was a good casting, and tests of the two pieces, one from the
upper and one from the lower end of the bar, should show
little, if any, difference in strength. No. 29 A was tested
with a load of 1,700 pounds, which caused an elongation of
0.15 inch. This load was then reduced to 1,250 pounds, and
the reading again taken, showing an elongation of 0.19 inch,
which increased in two minutes to 0.27 inch. The load was
then increased to 1,400 pounds, and the elongation was 0.32
inch. The load was allowed to remain on the bar for ten
minutes, and the elongation gradually increased to 1.7 inches,
when the bar broke. It seems probable from this test that
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 493
the load of 1,400 pounds would have broken the piece, even
if the load of 1,700 pounds had not been placed on it at the
beginning of the test.
C/3
Bar No. 29 B was tested in a different manner. The load
was gradually, but rapidly, increased to 2,100 pounds, with-
out stopping longer than was necessary to take the reading
494 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
of the elongations at 975, 1,180, 1,290, 1,600, and 2,000 pounds.
At 2,100 pounds, the elongation read 1.88 inches. The piece
then extended very rapidly, and, at the same time, its resist-
ance, as measured by the scale-beam, reduced to 1,700 pounds.
The pump of the hydraulic press was worked as fast as pos-
sible, but the beam could not be balanced beyond 1,700 pounds.
The piece sustained this load a few seconds, then broke after
an elongation of 2.58 inches.
Comparing the tests, it is seen that the resistance of No.
29 A to an elongation greater than 0.19 inch was never greater
than 1,400 pounds, while that of No. 29 B was 2,100 pounds,
or 50 per cent, more than the former ; which 50 per cent, ap-
parent increase of strength was evidently due to the greater
rapidity of the test of No. 29 B. The fact that the difference
in strength is only apparent is confirmed by the experiments
by torsional stress on pieces from the same bar. These
showed that torsion-pieces No. 29 A and No. 29 B, from the
top and from the bottom of the bar, tested by moderately
slow motion, each gave a resistance of 14.2 foot-pounds tor-
sional moment ; piece No. 29 C, from the middle of the bar,
tested in the same manner, resisted 13.2 foot-pounds, while
No. 29 D, a piece taken from the middle of the bar and ad-
joining No. 29 C, tested by very slow motion and left under
stress for hours, resisted only 9.2 foot-pounds or some 30 per
cent, less than either of the other pieces.
The effect of slow and rapid test is shown by both bars in
the tensile test. The average tenacity of all the pieces tested
is given as 3,130 pounds per square inch, but it is probable
that all the pieces would have broken at as low as 2,000
pounds if the test had been of long duration, say one hour,
or as high as 4,000 pounds if each test had been made in,
say, five minutes. The records of several tests follow.
The effect of time is also shown in the autographic strain-
diagrams (Fig. 30), and in the records calculated from them.
CONDITIONS AFFECTING STRENGTH OF AtLOYS. 495
TABLE XCI.
STRENGTH OF TIN AS VARYING WITH TIME OF TESTING.
•
Tests by Tensile Stress.
QUEENSLAND TIN, CAST.
No. 58 A.— Material : Tin cast in iron mould. Dimensions : Length, 5" (12.7 cm.) ;
Diameter, 0.798" (2 cm.).
LOAD PER SQUARE
INCH.
ELONGATION IN 5
INCHES.
. .
ELONGATION IN
PARTS OF ORIG-
INAL LENGTH.
LOAD PER SQUARE
INCH.
ELONGATION IN 5
INCHES.
6
in
ELONGATION IN
PARTS OF ORIG-
INAL LENGTH.
Pounds.
400
600
800
1,000
240
1,200
1,400
I, 600
I, 800
2,000
240
2,000
2,000 pO
for 14 mm
Minutes.
i
2
3
4
1
7
Inch.
0.0002
0.0027
O.OoSl
0.0175
Inch.
.00004
.0005
.00l6
•0035
Minutes.
8
9
10
ii
12
13
Resistai
square inc
side.
1,700 Ibs.
i min.
Resistai
broke 2 in
The fr
boundary
measured
Tensile
section, u
kilogs. pe
Total ti
Inch.
0.1997
0.2176
0.2328
o . 2490
0.2687
0.2929
ice reduced
h, and a cra<
0.3610
ice decrease
ches from A
actured sur
nearly ellii
0.580 and o.f
strength pe
nder slow st
r sq. cm.),
me of test, y
Pounds.
0.0159
0.0303
0.0433
0.0517
0.0630
0.0745
O.o86o
iinds per squ
utes, elongati
0.1070
0.1156
0.1298
o.i437
0.1580
0.1709
0.1861
.0062
.0086
.0103
.0126
.0149
.0172
3t constant
f as follows:
to 1,700 p
:k was obser
d gradually,
end.
ace had an
)tical ; two
85 inch,
r square inc
rain, 2,000 p
> minutes.
junds per
ved on one
.0722
.0863
and piece
irregular
diameters
ti, original
ounds (141
0.0756
are inch ke
on increasing
No. 58 B.
f°
0.0005
.0001
Stress kept constant for 2 minutes.
000
0.0029
.0006
i mm. 0.0724 | .0145
800
0.0051
.0010
2 min. 0.0821 .0164
1,000
0.0108
.0022
Increased stress rapidly for i minute, and
1,200
1,400
0.0184
0.0293
••
.0037
.0059
piece broke at 3,520 pounds per square inch.
Total time of test, 8 minutes.
I, 600
0.0394
..
.0079
Diameter of fractured section, 0.542 inch.
I, 800
0.0484
.0097
Tensile strength per square inch, original
2,000
6.0566
.0113
section under rapid strain, 3,520 pounds (248
240
......
o 0557
kilogs. per sq. cm.).
2,000
0.0631
.0126
1
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XCL— Continued.
TEST BY TRANSVERSE STRESS.
No. 58.— Material : Queensland tin cast in iron mould.— Dimensions : / = 22" (55.9 cm.) •,
b = i" (2.54 cm.) ; d = i" (2.54 cm.).
H
^
b
H
H
to
i
g
H
2
J
w
0-
w .
55 yj
b. :-'
w •
£ yi
fc« >«
si
||
O H
§1
OS U
W 2
11
II
Q
z
3
I
S
O
S
I
$
M
\
1
Pound*.
Inch.
Inch.
/^^W^J.
Inch.
Inch.
IO
Resistai
ice decreased in 8 minutes to 56
20
0.0118
5,574,991
pounds.
IOO
0.3033 ......
10
0.0087
no
0.3827
3°
0.0173
..
5,310,020
130
0.8091
40
0.0241
5,635,593
130
Cont'd
3
o 0126
i min.
1.07
60
i 36
70
80
0.0600
0.0859
till deflec
Ran pressure-screw down slowly
tion was more than 3 inches ; the
scale-bear
a vibrating all the time about 150
TOO
O.2IO9
pounds.
3
0 1753
1 Bent without breaking.
Breaking load, P — 150 pounds.
Resistance decreased in i minute to 70
pounds.
Modulus of rupture, R = -^TJ^ = 4,559
Resistance decreased in 3 minutes to 62
pounds.
(metric, 321).
The effect of prolonged stress on cast zinc is exhibited by
the following memorandum of test :
No. 21 (cast zinc). — Four pieces were tested by torsion,
which gave results nearly agreeing, the torsional moments
varying from 34.42 to 37.83 foot-pounds, and the angles of
torsion from 123 to 163 degrees. The strain diagrams of
these pieces exhibit marked peculiarities. No. 21 D was left
for fourteen hours under stress, just before reaching its maxi-
mum resistance. In this time the resistance decreased 15
per cent. On resuming the test, the piece slowly resumed
its -maximum resistance, which it held for some time. It was
then left under stress, and in about 30 seconds the resistance
decreased about 15 per cent. The piece then broke partly
through, and the resistance decreased to less than one-half
the maximum. On continuing the torsion, the piece held
by the unbroken side exhibited a constant resistance till it
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 497
was twisted through about 80 degrees further, when it broke
entirely across.
On No. 21 B experiments were made to determine the
effect of rapid and of slow stress and of resting under stress.
They indicated a decrease of resistance when resting under
stress, a uniform resistance to very slow motion, and a rapid
increase of resistance to rapid motion, except after the resist-
ance has reached the maximum, when rapid motion then
keeps the resistance constant.
It was observed that very ductile metals, such as tin
itself and alloys containing a large amount of tin, all exhibit
different amounts of resistance to slow and to rapid stress,
and a decrease of resistance on resting under stress. The
same phenomenon is exhibited by cast zinc, which is much
less ductile than the copper-tin alloys, and is less ductile
than several of the alloys of copper and zinc (those contain-
ing from 20 to 40 per cent, of zinc), which either did not
show the phenomenon at all, or but slightly.
281. The Effect on Bronze of long continued stress in
producing continuous distortion, even when the loads are far
within those required to produce the same effect on first
application, is well exhibited below.
TABLE XCII.
EFFECT OF TIME ON BRONZE.
Tests by Transverse Stress — With Dead Loads.
Samples i x i x 22 inches.
Ei
8
MATERIAL PARTS.
H
h
o
LOAD.
DEFLEC-
TION.
TIME.
INCREASED
DEFLEC-
BREAKING
WEIGHT.
6
2
Tin.
Copper.
TION.
Pounds.
Inches.
Inches,
Pounds.
7
100
600
0.534
5 minutes . . .
0.009
650
8
1.9
98.1
475
1 .762
3 minutes . . .
0.291
....
500
2.108
3 minutes . . .
0.488
500
9
7.2
92.8
950
0.348
5 minutes .. .
0.081
1.350
10
10.
90.
95°
0-395
5 minutes . . .
O.O2I
1,485
3-447
13 minutes . . .
4.087
1,485
ii
90.3
9.7
100
0.085
io minutes . . .
0.021
120
o. 140
10 minutes ...
°-°55
140
0.221
io minutes . ..
0.098
140
0.319
io minutes . . .
0.038
140
0 357
40 hours
0.920
..
32
49$ MATERIALS OF ENGINEERING—NON-FERROUS METALS.
TABLE HCII.— Continued.
6
MATERIAL PARTS.
b.
O
LOAD.
DEFLEC-
TION.
TIME.
INCREASED
DEFLEC-
BREAKING
WEIGHT.
0
z
Tin.
Copper.
Pounds.
Inches.
Inches.
Pounds.
160
1.294
10 minutes
0.025
1 60
1.320
i day
I.OOO
1 60
2.320
i day
I.OOO
1 60
3.320
i day
I.OOO
60
12
98.89
i. ii
90
120
120
0.243
0.736
1.791
5 minutes . . .
15 minutes . .
30 minutes . . .
0.063
1-055
0.748
1 2O
2.539
45 minutes . . .
0.595
.
120
3-I34
12 hours
8.000
120
J3
100
80
0.218
5 minutes
0.064
TIO
Metals having a composition intermediate between these
extremes have not been observed to exhibit flow or to in-
crease deflection under a constant load.
The same phenomena are exhibited by tests made in the
autographic testing machine,* thus :
&
d
•
MATERIAL.
TIME UNDER
STRESS.
ANGLE
OF TOR-
SION.
FALL OF
PENCIL.
REMARKS.
Tin.
Cop-
per.
ti
t2
t3
4
1
40 hours . . .
i hour
2 hours . . .
12 minutes .
O
65
1 80
280
*38°
0.06 inch.. .
o.i inch...
o.i inch...
50 per cent .
Recovered after further distortion of i°.
Recovered in 8°.
Recovered in 80°.
Did not recover.
Behaved like No. 4.
Did not recover.
100
....
99-44
9 Ail
0.56
i. n
oy.
58
0.2 inches.
Tests by tension with similar materials exhibit similar
results, and these observations and experiments thus seem to
indicate that, under some conditions, the phenomena of flow,
and of variation of the elastic limit by strain, may be co-
existent, and that progressive distortion may occur with
" viscous " metals.
282. A Fluctuation of Resistance with Time, illustrated
in the table here given, is a singular phenomenon which has
been observed by the Author, but the causes of which remain
* Part II. , p. 379. f Same piece. \ Taking " elasticity line."
CONDITIONS AFFECTING STRENGTH OF ALLO VS. 499
TABLE XCIII.
FLUCTUATION OF RESISTANCE.
Test by Transverse Stress.
ALLOY OF COPPER AND TIN.
No. 47.— Material : Alloy.— Original mixture: 17.5 Cu, 82.5 Sn.— Dimensions : Length
between supports, 22"; Breadth, 0.996"; Depth, 0.983".
LOAD.
DEFLEC-
TION.
A
SET.
MODULUS OF
ELASTICITY.
/>/3
LOAD.
DEFLEC-
TION.
A
SET.
MODULUS OF
ELASTICITY.
Pt*
4 A bd*
4 A bd*
Pounds.
10
20
£
80
100
5
120
I40
160
180
200
5
ROO
220
240
260
270
280
290
300
Theb
reading
5
The b
poise til
Time
Inch.
0.0027
0.0070
0.0153
0.0256
0.0365
Be
0.0499
0.0617
0.0804
o. 1042
0.1343
6.1666
o'.i798
0.2145
0.2503
0.3021
0-3367
0.3762
0.4147
°-4597
;am was obs<
of set was ta
earn rose aj
beam balan
2 minutes.
Inch.
am sinks slo\
8,039,339
7,356,258
6,594,770
6,167,163
vrly.
5,638,814
5,472,481
4.899,597
4,320,565
3,77^245
3,377,873
In 2
pounds
back ti
and anc
Pounds.
Be5am
In 2 r
In 10
In 39
Rant
again a
In 4 r
In 23
Inir
at 20 po
Rant
again a
To5tal
utes o.-
Replz
280
300
Ireal
Modu
minutes moi
The press
1 beam bala
>ther reading
Inches.
•e, beam ba
ure-screw w
need again
of set taken
Inch.
0.2998
iced at 10 po
need at 16 p<
need at 23 pc
-screw till be
0.2902
rose again,
n balanced c
minutes be<
-screw till be
0.2845
-et in 2 hours
= 0.0239 inc
280 pounds.
anced at 14
as then run
at 5 pounds,
rose again,
ninutes balai
minutes bala
minutes bala
>ack pressure
: 5 pounds.
ninutes bean:
minutes beai
our and 36
unds.
>ack pressure
; 5 pounds.
decrease oj*
084-0.2845
iced load of
0.4849
0.5332
Broke on a
dng load, 30
us of ruptur
unds.
Hinds,
mnds.
am balanced
it 14 pounds,
im balanced
am balanced
0.0092
0.0821
2,697,980
832,406
and 20 min-
i.
0.3084
;rved to rise,
ken in 2 min
0.3022
fain, pushed
ced at 10 pou
and another
utes.
forward the
nds.
pplying strain.
D pounds.
2, R = ^ = 10,288.
2<W2
No. 48.— Material : Alloy. -Original mixture: 12.5 Gu, 87.5 Sn. - Dimensions : Length
between supports, 22"; Breadth, 0.985"; Depth, 0.990".
10
20
40
60
80
100
5
120
140
160
180
200
5
200
220
240
260
270
280
200
300
5
0.0025
0.0050
0.0141
0.0230
0.0^52
Bea
0.0508
0.0760
0.0969
0.1262
0.1592
0.2044
0.2268
0.2916
0.4078
0.5210
o.5763
0.6458
0.7185
0.8025
Scale beam rose.
In 2 minutes balanced at 20 po
In 4 minutes balanced at 29 po
In 15 minutes balanced at 34 p
Ran back pressure-screw till be
again at 5 pounds.
5 | I 0.6555
Beam rose again, balanced at
5 minutes.
5 ! .0.6508.
Total decrease of set in 20 mini
0.6508 = 0.0234 inch.
Beam rose again, but test w
without further waiting.
unds.
unds.
ounds.
am balanced
12 pounds in
ites, 0.6742—
is continued
m sinks slov
0.0120
7,901,458
7,249,195
6,330,144
rty-
5,482,803
4,397^784
4,024,116
3,53],237
0.1238
2,725,307
;.".*.:;
1,639,194
300 1.0760 Beam sank rapidly.
300 Repeated. Bar broke just as beam
rose.
Breaking load, 300 pounds.
o/V
Modulus of rupture, R = —^ = 10, 254.
0.6742
1,207,609
1,041,220
500 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
to be determined. The bars tested as shown were not per-
fect in structure, and do not exhibit any considerable strength ;
they consist principally of tin (82.5 and 87.5 per cent.) and
are valueless for the ordinary work of the constructor, although
useful " white metals." It is seen that the resistance of both
bars was, at times, overcome by the load, but, on balancing
the weigh-beam, the bar each time gradually re-acquired a
power of raising the load which had deformed it, and straight-
ened itself sufficiently to raise the beam against the upper
" chock." A decrease of set took place of 0.02 inch — in the
first beam in two hours and twenty minutes, and in the
second in twenty minutes. In two minutes, recovery occurred
to such an extent that the bar exerted an effort of 20 pounds
tending to straighten itself, and in 15 minutes of 34 pounds.
The phenomenon is one which will demand careful investi-
gation.
283. The Effect of Unintermitted and Heavy Stress on
Resistance is well exhibited on the two sets of strain-dia-
grams* here reproduced from Part II. of this work. The
first series of tests exhibited decrease of resistance with time
No. 655 was a bar of Queensland tin, presented to the
Author by the Commissioner of that country at the Centen-
nial Exhibition, and which was found to be remarkably pure.
A load of loo pounds gave a deflection of 0.2109 inch, and
produced a set of 0.1753 inch. The same load restored de-
flected the bar 0.24 1 5 inch, which deflection being retained,
the effort to regain the original shape decreased in one min-
ute from 100 to 70 pounds, in 3 minutes to 62, and in 8 min-
utes to 56 pounds. The original load of 100 pounds then
brought the deflection to 0.3033 inch, nearly 50 per cent,
more than at first.
A bar, No. 599, of copper-zinc alloy, similarly tested,
deflected 0.5209 inch under 1,233 pounds, and took a set of
0.2736 inch after being held at that deflection 15 minutes,
the effort falling meantime to 1,137 pounds. Restoring the
load of 1,137 pounds, the deflection became 0.5131 inch, and
the original load of 1,233 pounds brought it to 0.5456 inch.
* Trans. American Society of Civil Engineers, 1877.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. SO I
The bar was now held at this deflection and the set gradually
took place, the effort falling in 15 minutes to 1,132 pounds
(4 per cent, more than at the first observation), in 22 minutes
to 1,093, in 46 minutes to 1,063, in 63 minutes to 1,043, m
91^ minutes to 1,003, an<^ m ll% minutes to 911 pounds, at
which last strain the bar broke 3 minutes later, the deflection
remaining unchanged up to the instant of fracture. This
remarkable case has already been referred to in an earlier
article, when treating of the effect of time in producing varia-
tion of resistance and of the elastic limit.
Nos. 561, copper-tin, and 612, copper-zinc, were composi-
tions which behaved quite similarly to the iron bar at its
first trial, the set apparently becoming nearly complete,
in the first after I hour, and in the second after 3 or 4
hours.
In all of these metals, the set and the loss of effort to
resume the original form were phenomena requiring time for
their progress, and in all, except in the case of No. 599 —
which was loaded heavily — the change gradually became less
and less rapid, tending constantly toward a maximum.
So far as the observation of the Author has yet extended,
the lattef is always the case under light loads. As heavier
loads are added, and the maximum resistance of the material
is approached, the change continues to progress longer, and,
as in ^h^ case of the brass above described, it may progress
so fa? as to produce rupture, when the load becomes heavy,
up t*> a limit, which closely approaches maximum tenacity in
the **?ron class." The brass broke under a stress 25 per cent,
less than it had actually sustained previously.
The records are herewith presented, and the curves repre-
senting them shown in the figures which follow.
502 MA TERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XCIV.
DECREASE OF RESISTANCE AND INCREASE OF SET OF METALS, WITH TIME,
Bars i inch square ; 22 inches between supports.
TIME.
Min.
25
100
275
320
320
322
322
No. 561.
I
2,640
4,140
No ss
15
15
28
4°
46
63
77-5
9i.5
LOAD.
LOSS OF LOAD.
DEFLECTION.
SET.
TIME.
LOAD.
LOSS OF LOAD.
DEFLECTION.
SET.
No. 64i
f
Pounds.
1,003
3
1,003
999
99i
987
987
«i
1,003
2,720
Se
1,003
-27.5 PA
160
5
160
154
150
104
IOO
5
IOO
160
320
9.— 10 PA
,233
,137
3
,137
,233
,133
,093
,070
,063
1,043
1,023
1,003
WROUG*
'irst Tria
Pounds.
4
12
16
16
cond Trii
RTS COPPE
"6
TO
f
60
RTS COPPE
IOO
140
I63
I70
IOO
210
230
T IRON.
/.
Inches.
0.0995
O.IOOI
O.IOOI
O.IOOI
O. IOOI
O.IOOI
0.9910
0.1003
2.6400
*/.
2.2548
R, 72-5 PA
0.0696
0.072
0.072
0.072
0.072
0.072
0.0763
0.0970
0.2200
R, 90 PAR"
0.5209
0.5209
0.5131
0.5456
0-5456
0.5456
0.5456
0.5456
0.5456
0.5456
0.5456
Inch.
0.0049
Min.
i
2
3
23
53
133
f
363
Pounds.
1,603
1,521
i,493
1,483
J,463
1,461
r,459
i,457
i,457
3
i,457
1,603
2,720
Pounds.
'82
110
120
140
142
144
146
146
Inches.
0.287
0.287
0.287
0.287
0.287
0.287
0.287
0.287
0.287
o'.2863
0.3016
2.6400
Inch.
0.1091
o. 1481
0.007
RTS TIN.
0.0145
96.5
118
121
No. 612.
993
911
9ti
-47-5 PAI
800
800
%
766
756
75*
3
751
800
I, IOO
No. 655.-
100
3
IOO
70
62
56
IOO
ISO
240
322
326
JTS COPPE
10
22
34
44
49
-QUEENS
^
44
0.5456
R, 52.5 PA
0.3332
0.3366
0.3366
0.3366
0.3366
0.3366
0.3366
0.3364
0.349°
uAND TIN.
0.2109
0.2415
0.2415
0.2415
0.2415
0.3033
Bent rs
Broke
RTS ZINC.
0.1478
o! 688
Broke
o T753
pid'ly."
0.04
Broke
rs ZINC.
5
25
1 20
480
1,320
0.2736
:::: :
i
284. The Observed Increase of Deflection Under Static
Load. — In the preceding article the writer presented results
of an investigation made to determine the time required to
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 503
produce " set " in metals belonging to the two typical classes,
which exhibit, the one exaltation, and the other a depression
of the elastic limit under strain.
The experiments there described were made by means of
300
FIG. 31. — DECREASE OF RESISTANCE WITH TIME.
Rate of set of Bars i inch square 22 inches between supports.
a testing-machine, in which the test-piece could be securely
held at a given degree of distortion, and its effort to recover
its form measured at intervals, until the progressive loss of
effort could no longer be detected, and until it was thus in-
dicated that set had become complete.
The deductions were :
That in metals of all classes under light loads this de-
504 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
crease of effort and rate of set become less and less notice-
able until, after some time, no further change can be
observed, and the set is permanent.
That in metals of the " tin class," or those which had
been found to exhibit a depression of the elastic limit with
intermitted strain, under a heavy load, i. e., a load consider-
ably exceeding the proof strain, the loss of effort continued,
until, before the set had become complete, the test-piece
yielded entirely.
And that in the metals of the "iron class," or those
exhibiting an elevation of elastic limit by strain, the set be-
came a maximum and permanent, and the test-piece remained
unbroken, no matter how near the maximum load the strain
may have been.
The experiments here described were conducted with the
same object as those above referred to. In these experi-
ments, however, the load, instead of the distortion, was made
constant, and deflection was allowed to progress, its rate
being observed, until the test-piece either broke under the
load or rapidly yielded, or until a permanent set was pro-
duced. The results of these experiments are in striking
accordance with those conducted in the manner previously
described. They exhibit the fact of a gradually-changing
rate of set for the several cases of light or heavy loads, and
illustrate the striking and important distinctions between the
two classes of metals even more plainly than the preceding.
The accompanying record and the strain-diagrams, which are
its graphical representation, will assist the reader in compre-
hending the method of research and its results. All test-pieces
were of one inch square section, and loaded at the middle.
The bearings were 22 inches apart.
No. 651 was of wrought iron from the same bar with No.
648.* This specimen subsequently gave way under a load of
2,587 pounds. Its rate of set was determined at about 60 per
cent, of its ultimate resistance, or at 1,600 pounds. Its de-
flection, starting at 0.489 inch, increased in the first minute,
0.1047; in the second minute, 0.026; in the third minute,
* Trans. Am. Soc., C. E., vol. v., page 208.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. $O$
0.0125; in the fourth minute, 0.0088; in the fifth minute,
0.0063; and in the sixth minute, 0.0031 inch; the total de-
flections being 0.5937, 0.6197, 0.6322, 0.641,0.6473, and 0.6504,
inch. In the succeeding 10 minutes the deflection only
increased 0.0094 inch, or to 0.6598 inch, and remained at that
point without increasing so much as o.oooi inch, although the
load was allowed to remain 344 minutes untouched. The bar
had evidently taken a permanent set, and it seems to the
writer probable that it would have remained at that deflection
indefinitely, and have been perfectly free from liability to
fracture for any length of time.
This bar finally yielded completely, under a load of 2,589
pounds, deflecting 4.67 inches.
No. 479 was a bronze bar containing 3^ per cent, of tin.
Its behavior may be taken as typical of that of the whole
" tin class " of metals, as the preceding illustrates the behavior
of the " iron class " under heavy loads. It was subjected to
two trials, the one under a load of 700 and the other of 1,000
pounds, and broke under the latter load, after having sus-
tained it ij^ hours. The behavior of this bar will be con-
sidered especially interesting, if its record and strain-diagram
are compared with those of No. 599, previously given, which
latter specimen broke after 12 1 minutes, when held at a con-
stant deflection of 0.5456 inch ; its resistance gradually falling
from an initial amount of 1,233 pounds, to 911 pounds at the
instant before breaking.
This bar, No. 479, was loaded with 700 pounds " dead
weight," and at once deflected 0.441 inch. The deflection
increased 0.118 inch in the first five minutes, 0.024 in the
second five minutes, 0.018 in the second ten minutes, 0.17 in
the fourth, 0.012 in the fifth, and 0.008 inch in the sixth ten
minute period, the total set increasing from 0.441 to 0.65
inch. The record and the strain-diagram show thaf at the
termination of this trial the deflection was regularly increas-
ing. The load was then removed and the set was found to
be 0.524 inch, the bar springing back 0.126 inch on removal
of the weight.
The bar was again loaded with t,ooo pounds. The first
506 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
deflection which could be measured was 3.118 inches and the
increase at first followed the parabolic law noted in the pre-
ceding cases, but quickly became accelerated ; this sudden
change of law is best seen on the strain-diagram. The
new rate of increase continued until fracture actually oc-
curred, at the end of i^ hours, and at a deflection of 4.506
inches.
This bar was of very different composition from No. 599 ;
it is a member of the " tin class," however, and it is seen, by
examining their records and strain-diagrams, that these
specimens, tested under radically different conditions, both
illustrate the peculiar characteristics of the class, by similarly
exhibiting its treacherous nature.
No. 504 was a bar of tin containing about 0.6 per cent, of
copper — the opposite end of the scale — and exhibited pre-
cisely similar behavior, taking a set of 0.323 inch under no
pounds and steadily giving way and deflecting uninterruptedly
until the trial ended at the end of 1,270 minutes, over 21
hours. This bar, subsequently, was, by a maximum stress of
130 pounds, rapidly broken down to a deflection of 8. 1 1
inches.
No. 501 presents the finest illustration of this phenomenon
yet met with by the Author. The test extended over nearly
2^ days under observation, and the bar left for the night was
found next morning broken. The time of fracture is there-
fore unknown, as is the ultimate deflection. The record
is, however, sufficient to determine the law, and the strain-
diagram is seen to be similar to that of the second test of No.
479, exhibiting the same tendency to the parabolic shape and
the same change of law and reversal of curvature preceding
final rupture, and illustrates, even more strikingly, the fact
that this class of metals is not safe against final rupture, even
though the load may have been borne a considerable time,
and have apparently been shown, by actual test, to be capable
of sustaining it. A strain-diagram of each of the latter two
bars is exhibited on a reduced scale to present to the eye
more strikingly this important characteristic.
A comparison of the records and the strain- diagrams with
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 5O/
those of the preceding article, in illustration of the behavior
of the two classes of metals under constant deflection, is most
FIG. 32. — INCREASE OF DEFLECTION WITH TIME.
Rate of Set of Bars i Inch Square 22 Inches Between Supports.
S'SgS: S 8 8; S g
instructive. It will still be necessary to make many experi-
ments to determine under what fraction of their ultimate
resistance to rapidly applied and removed loads, the members
of the "tin class" — the viscous metals — will be safe under
static permanent loads. The records in Table LXXXIII.,
Art. 267, present many illustrations of the phenomenon here
considered.
508 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
TABLE XCV.
INCREASE OF DEFLECTION WITH TIME.
Bars, i inch square ; 22 inches between supports. Load applied at the middle.
i
O
|
INCREASE.
jj
INCREASE.
TIME.
a
3
Q
Difference.
Total.
8
Q
Difference.
Total.
No. 651. — WROUGHT IRON.
Min.
Inches.
Inches.
Inches.
Load) i, 600 pounds.
30
4°
0.618
0.630
0.017
0.012
0.177
0.189
Min.
o
Inches.
0.4890
Inches.
Inches.
So
60
c^*
0.642
0.650
O.OI2
0.008
0.201
0.209
i
2
0-5937
0.6197
0.1047
0.0260
0.1047
0.1307
bet
0.524
*****
3
0.6322
0.0125
0.1432
Second Trial. — Load, 1,000 pounds.
4
0.6410
0.0088
0.1520
5
0.6473
0.0063
0.1583
o
3.118
6
0.6504
0.0031
0.1614
5
3-540
0.422
0.422
16
0.6598
0.0094
0.1708
15
3.660
0.120
0.543
344 0.6598 o.oooo
Maximum load, 2,589 pounds ;
deflection, 4.67 inches.
0.1708
maximum
45
Broke
4.102
7.634
bar under i ,
0.442
3-522
ooo pounds.
&
No. 504. — 0.557 PARTS COPPER, 99.443 PARTS TIN.
NO. 501.— 9.7 PARTS COPPER, 90.3 PARTS TIN.
o
Load, no pounds.
o 323
o
Load, 1 60 pounds.
. 294 .....
5
0.406
0.083
0.083
10
.319
0.025
0.025
845
L945
1-539
1.622
.70
-463
0.144
0.169
865
2.005
0.059
1.681
130
0.067
0.236
895
2.138
0.134
1.815
310
.691
0.161
0-397
1,025 i 2.248
O.IIO
1-925
400
.766
0-075
0.472
1,110 j 2.378
0.130
2.055
460
.811
0.045
0.517
1,270 ; 2.626
Maximum load, i
0.248
30 pounds ;
2.303
maximum
1,360
J,475
-534
.697
0.723
o. 163
1.240
1.403
deflection, 8.11 inches.
1,565
.782
0.085
1.488
•938
0.156
1.644
I, 88O
3 • *3^
0.198
1.842
No. 479.— 96.27 PARTS COFFER, 3.73 PARTS TIN.
2,780
2,940
3-798
4.274
0.662
0.476
2.504
2.980
O
Load,
0.441
700 ponnds.
»
3,000
3,295
Bar 1(
4-349
5-097
;ft under st
0.075
0.748
ram at nierh
3-055
^.803
t and found
5
0-559
0.118
0.118
broken in the morning.
10
0-583
0.024
0.142
20
0.601
0.018
0.160
285. Depression of Elastic Limits. — The effects of inter-
mitted stress and of interrupted strain are of peculiar interest
and importance with the non-ferrous metals and the alloys.
So far as they have been observed by the Author, they are
often precisely the opposite of those noted in experiments on
merchant iron and commercial grades of steel. They are
well illustrated in Fig. 33, which is here reproduced from
Part II.
CONDITIONS AFFECTING STRENGTH OF ALLOYS. $09
These strain-diagrams are obtained by transverse test,
from bars of common iron, Nos. 648, 649, 650, 651, and from
two specimens of bronzes, Nos. 596, 599, all of the same size,
I inch (2.54 cm.) square and 22 inches (55.9 cm.) between sup-
ports.
The first strain diagram to be studied is that of a bar of
the most ductile metal (No. 599, copper, 10; zinc, 90). It
exhibits clearly the phenomenon of flow with a depression of
the elastic limit under constant load.
5IO MATERIALS OF ENGINEERING— NON-FERROUS METALS.
This bar was left deflected under a load of 163 pounds
(74 kgs.). It gradually lost its power of restoration until it
only exhibited an effort of 143 pounds (65 kgs.). The curve
exhibits the relation of deflection to deflecting force. The
resistance gradually increased as deflection progressed until
the load — 403 pounds (183 kgs.) — produced a deflection of
0.09 inch (0.23 cm.). The bar was again left, and, under a
fixed deflection, again lost resisting power, and the effort to
straighten itself fell to 333 pounds (151 kgs.).
Finally, the bar offered its maximum resistance of 1,233
pounds (560 kgs.) under a deflection of 0.545 inches (1.3 cm.),
and was then held in its flexed position. Gradually its effort
to restore itself grew less and less, until, when it had fallen to
911 pounds (414 kgs.), the bar suddenly snapped and the two
halves fell to the floor.
No. 596 (copper 25, zinc 75) similarly exhibited a depres-
sion of the elastic limit by strain, but, vastly harder, more
elastic and brittle, it broke under 663 pounds (301 kgs.) and
at a deflection of o.i 136 inch (0.3 cm.), before apparently pass-
ing the point termed the primitive or apparent limit of elastic-
ity by the Author, i. e., that point at which the sets become
nearly proportional to the strains, and at which the line of the
strain-diagram turns sharply away from the vertical.
The strain-diagram No. 648, common iron, is that of the
type of that class in which the elevation of the elastic limit
has been detected by the Author.
The bar was like the preceding, of I inch (2. 54 cm.)
square section and 22 inches (55.88 cm.) in length between
bearings. It reached its elastic limit at 1,450 pounds
(659 kgs.) and at a deflection of 0.15 inch (0.4 cm.). Pass-
ing this point, and at a deflection of 0.287 inch (0.7 cm.), the
bar was held at a constant deflection, under a load of 1,600
pounds (727 kgs.). Flow occurring, the effort to regain its
original shape became less and less, until in six hours it had
fallen to 1,457 pounds (662 kgs.). Continuing the test, re-
sistance and deflection increased as indicated by the curve,
instead of following the original direction.
Similar increase of resisting power under strain is seen at
CONDITIONS AFFECTING STRENGTH OF ALLOYS. 5 I I
other points on the curve, and whenever the process of dis-
tortion was interrupted long enough to permit flow and that
re-arrangement of particles which has been described. An
hour or two usually gave time enough to bring out this re-
markable phenomenon.
This action has been discovered in iron and steel, and
under every form of strain — tension, torsion, compression and
cross-breaking — and it would seem that aside from accidental
overstrain, producing incipient rupture or loss of strength due
to such action as abrasion or corrosion, length of life of iron
structures under strain was in itself, apparently, a source of
increased safety. On the other hand, as is here seen, the be-
havior of non-ferrous metals is precisely the opposite, and
the engineer is compelled to use them with greater caution
and to base his calculations upon a higher factor of safety,
a conclusion fully corroborated by the work of Wohler.
Recurring to Fig. 33, a resemblance is to be noted in
the behavior of both classes of metals.
The bars No. 649, 650 and 651 were tested by rapidly in-
creased load up to the breaking point, allowing no time for
reading of sets.
The first of this set deflected 0.014 inch (0.04 cm.) under
loo pounds (45 kgs.), 0.052 under 500 pounds, 0.098 under
1,000 pounds, and 0.18 under 1,500 pounds. At 1,600 pounds
the deflection was 0.2854 inch, and the bar yielded to the
stress, and the deflection became 0.363 in 2^ minutes. Under
1,640 pounds the deflection increased in six minutes from
0.383 to 0.440 inch, and a maximum resistance was recorded
of 2,350 pounds (1,070 kgs.), and a deflection of 5-577 inches
(15 cm.). This bar was tested in a similar manner to the
preceding, and in the same machine.
Numbers 650 and 651 were tested by dead loads — i.e.,
by laying upon them heavy weights. By this method the
deflection could increase to a maximum under each load, in-
stead of being kept constant, as in the testing machine. No.
650 was rapidly broken without allowing time for completion
of set or any considerable exaltation of the elastic limit. The
plotted curves of results exhibited well the striking difference
$12 MATERIALS OF ENGINEERING— NON FERROUS METALS.
of behavior between this bar and 651, which was purposely
given time for set and for exaltation of the elastic limit. At
i, 500 pounds (682 kgs.) each had deflected nearly the same
amount, and had passed the elastic limit, as usually called.
The first, however, gave way completely with 2,260.5 pounds
(1,027 kgs.), while the second, after several times exhibiting
an elevation of the elastic limit — as at 1,500, 1,600, 1,700,
1,900, 2,300, 2,400 and at 2,500 pounds — finally only yielded
entirely at 2,589. The first only deflected 2^ inches (7 cm.);
the second, 4.67 inches (11.9 cm.); although when the latter
was loaded with about the weight at which the first yielded, it
deflected about the same amount.
The last bar was left two and a half days under its final
load, and its deflection increased from 4.275 inches (10.9 cm.)
to 4.67 (11.9 cm.), when the weights reached the supports of
the frame and the test was ended. The other bar sank
rapidly after being loaded with 1,600 pounds (726 kgs.).
Both classes of metals, when flexed, were shown to exhibit
less and less effort to restore themselves to their original
form. In the case of the tin class, as the Author has called
it, this continues indefinitely. With the iron group this loss
of effort gradually becomes less and less and reaches a limit
at which the bar is found to become stronger than at first.
The two classes are thus seen to be affected by time in
precisely the same manner initially, but finally in exactly
opposite ways.
286. The Effect of Variable Stress in causing variation
of the normal series of elastic limits observed during ordinary
tests is well shown by the records of test of the copper-zinc
alloys. The following are extracts from the memoranda
taken during tests made for the U. S. Board to which fre-
quent references are made. Similar illustration may be
found among the records of tests, both of bronzes and of
brasses, already given.
Bar No. 8 (60.94 copper, 38.65 zinc) bent to a deflection of
3^2 inches under a load of 1,140 pounds. The apparent
elastic limit was reached at about 640 pounds. At 400
pounds the bar was left under stress for eighteen hours, at the
CONDITIONS AFFECTING STRENGTH OF ALLO YS. 5 I 3
end of which time the scale-beam was found still balanced,
the resistance to a constant deflection being unchanged. At
800 pounds the scale beam dropped and the resistance de-
creased 1 8 pounds in one hour.
After leaving the bar under a stress of 800 pounds for one
hour, taking the reading of a set, then applying a stress of
840 pounds, the deflection was 0.0185 inch over the deflection
produced by 800 pounds. The load was increased to 880
pounds, and the deflection increased 0.441 inch. An ad-
ditional 20 pounds then increased the deflection only 0.020
inch, and another 20 pounds only 0.0515 inch. Success-ive
additions of 20 pounds at a time were applied, and the in-
creased amounts of deflection were as follows : 0.22, 0.07, 0.20,
0.09,0.25,0.10,0.25, o.io inch. The time occupied in applying
the load was as regular as possible, about 30 seconds. This
irregularity of resistance to distortion has been also observed
both in tensile and torsional tests of pieces obtained from
the same bar, and of other bars of nearly similar composi-
tions.
Bar No. 10 (49.66 copper, 50.14 zinc) broke at a load of 940
pounds after a deflection of 1.257 inches. The weakness was
due to unfavorable conditions of casting. The fractured sur-
face showed a finely porous or spongy surface, and the com-
position was not homogeneous. The limit of elasticity
was passed at 320 pounds. At 200 pounds the scale beam
was observed to sink very slowly.
After 200 pounds had been applied, a slight crackling
sound like the " cry of tin " was heard to proceed from the
bar, which continued for two or three minutes, while the de-
flection was held constant by the pressure-screw. After it
had ceased to be distinctly audible it could be heard on ap-
plying the ear to the bar. With every increase of load the
same phenomenon took place till the bar broke.
After 940 pounds had been applied, slight cracks were
heard and the scale-beam dropped. The poise was pushed
back and the beam balanced at 580 pounds. No crack could
be perceived in the bar, and no indication of fracture. After
reading the deflection the pressure was then taken off the bar
33
MATERIALS OF ENGINEERING— NON-FERROUS METALS
and a reading of set taken. The pressure was again gradually
applied, and when it reached 500 pounds the bar broke.
The sudden decrease of resistance from 940 to 580 pounds
without visible appearance of breaking cannot be explained.
The crackling sound emitted by the bar during the whole
test after passing a load of 200 pounds, and when it was held
at a constant deflection for several minutes, is evidence of
molecular change, probably the " flow of metals " described
by Tresca.
Bar No. 11 (47.56 copper, 52.28 zinc) behaved much like
No. 10, but was much stronger, breaking at 1,360 pounds.
The elastic limit was passed at 450 pounds. At 460 pounds
the scale-beam sank about 16 seconds after it balanced.
At 560 pounds a crackling sound was heard from the bar like
that emitted from bar No. 10, which continued for 10 minutes,
gradually growing fainter. With the same deflection, the re-
sistance decreased 50 pounds in 15 hours. On proceeding
with the test the next day, the crackling sound was again
given out by the bar, and continued till the bar broke at
1,360 pounds, after a deflection of 1.17 inches.
Bar No. 19 (10.30 copper, 88.88 zinc) was similar in charac-
ter to other bars containing a large proportion of zinc, but
was stronger, sustaining a load of 1,233 pounds before rupture.
It broke, however, at 911 pounds, two hours after it had sus-
tained the load of 1,233 pounds. The total deflection before
breaking was 0.5456 inch. The record of this test is given in
full in the tables, and is entirely unlike that of any other bar
tested. Three " time tests " were made at 163, 403, and 1,233
pounds, which showed the common phenomenon of decrease
of resistance with time. In the last case the resistance de-
creased from 1,233 to i, 137 pounds in fifteen minutes. After
taking a reading of the set, the load of 1,233 pounds was again
applied and the decrease of resistance with time noted at
intervals during a period of two hours.
The decrease of resistance was at first rapid, 100 pounds
in the first fifteen minutes, and then much slower. In the
fifteen minutes, commencing at one hour and three minutes
after the beginning of the " time test," the decrease was 20
CONDITIONS AFFECTING STRENGTH OF ALLO YS. $1$
pounds ; in the next fourteen minutes the decrease was again
20 pounds. In the five minutes, commencing one hour and
thirty-two minutes after the " time test/' the decrease was 10
pounds, showing an increase of the rate of decrease. Another
observation was twenty-two minutes, when the rate was found
to have largely increased, the decrease of resistance in these
twenty-two minutes being 82 pounds. In three minutes
after taking the last reading, when it balanced at 911 pounds,
the bar suddenly broke without warning. The deflection was
unchanged during this entire " time test." The elastic limit
was reached at about 900 pounds.
287. The Effect of Repeated Strain is greater with the
non-ferrous metals, and usually with the alloys, than with iron
and steel. The investigations of Wohler and Spangenberg
were made principally upon the latter class of materials, but
were also made to cover the action of a few other metals.
Wohler's law, that the rupture of a piece may be pro-
duced by the repeated action of a load less than that which,
once applied, would cause fracture, is true, probably, of all the
non-ferrous metals, and this effect is with them much more
serious than with the ferrous metals. Spangenberg found
that gun bronze in tension would endure a stress of 22,000
pounds per square inch (1,547 kgs. per sq. cm.) laid on and at
once removed 4,200 times before rupture; a stress of 16,500
pounds (i,i6okgs.) 6,300 times, and 11,000 pounds per square
inch (773 kgs. per sq. cm.), 5,547,600 times. It may be con-
sidered safe under indefinitely repeated loads falling well
under one-half its tenacity as determined by ordinary test.
Phosphor bronze, forged, bore 53,900 repetitions of the small-
est of the above loads, and 2,600,000 of the next load, but
broke under 1,621,000 repetitions of a load of 13,750 pounds
per square inch (967 kgs. per sq. cm.). The cast metal sus-
tained 408,350, 2,731,161 and 2,340,000 repetitions of the
same loads. This peculiar behavior is not explained by the
experimenter.
Further experiment in this direction is desirable. Mean-
time, the engineer will probably find it advisable to allow, for
intermittent loads, but one-half the stresses which would be
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
permitted for single applications of load, and one-quarter
where suddenly applied, while the factor of safety should
be probably not less than one-half greater for non-ferrous
material than with iron. The limits of stress sometimes pro-
posed are not far from the following, which may be compared
with the values already given for factors of safety and ulti-
mate strength.
TABLE XCVI.
PERMISSIBLE REPEATED STRESSES FOR NON-FERROUS METALS.
FACTOR OF SAFETY.
MAXIMUM STRESS.
Dead
Load.
Live
Load.
Dead Load.
Live Load.
Lbs. per
sq. in.
Kgs. per
sq. cm.
Lbs. per
sq. in.
Kgs. per
sq. cm.
Copper, cast
4
4
4
4
4
4
4
4
8
8
8
8
8
8
8
3
5,ooo
15,000
16,000
10,000
5,000
10,000
12,000
1,000
352
1,055
1,125
703
352
703
845
70
2,500
7,500
8,000
5,000
2,500
5,ooo
6,000
500
176
528
563
352
176
352
423
35
' * forged
" wire
Gun-bronze, cast
Brass, yellow, cast . . .
rolled .
wire..
Lead ' rolled
When the stresses are reversed, as in connecting rods, the
factor of safety should be doubled and the maximum stresses
reduced at least one-half. [See Appendix for Table of Prop-
erties of Metals and Alloys.]
CHAPTER XIV.
MECHANICAL TREATMENT OF THE METALS.*
288. Qualities Affected by Mechanical Treatment—
The metals used by the engineer in construction, as they are
found in the market, and often when they have been given
the form and dimensions desired in the finished piece, are
known to be liable to exhibit certain defects and to possess
certain peculiar characteristics. Some of these defects are
removable by proper mechanical treatment, and some of the
characteristic qualities may be modified in a marked manner
by special methods of manipulation. All known and actually
practised methods of so altering the character of the metals
used by the engineer, involve, directly or indirectly, the ele-
vation of the original elastic limit of the material; and they
usually produce a change, more or less marked, in the
ultimate strength, the elasticity, the resilience — in fact, in
all the physical properties of the metal.
The subject of the mechanical treatment of metals has
already been considered, incidentally, and to a very limited
extent, in Part II. of this work.t It is intended, in the pres-
ent chapter, to describe successful and established methods
at some length, when they have not already been so described.
The effect of mechanical treatment is due to that change of
volume, density, and condition of molecular aggregation which
is produced by any action causing flow while under stress,
and, especially, while under compression. J This action is
sometimes, as in wire drawing, incidental to the process of
* Principally from an article contributed to the Metallurgical Review, 1877.
f Part II., §§ 48, 165, 178, 191, pp. 71, 196, 262, 328
\ Part II., Chapter X.
5l8 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
manufacture, and sometimes, as in the Whitworth or Jones
systems of compressing ingot metal, and as in the cold-rolling
process, an independent operation.
Mechanical treatment does not directly modify the chenv
ical composition of the metal, and is, therefore, incapable of
changing, either for better or worse, the nature of the mate-
rial, so far as it is determined by the chemical constitution.
So important, however, are the modifications which can be
effected by mechanical treatment, and so extensively are they
likely to be applied in the arts, that a more extended and a
more precise analysis than can be here given would be re-
quired to do full justice to the subject.
All defects removable by mechanical treatment may be
properly classed as defects involving want of homogeneous-
ness. Metals maybe homogeneous in two ways : (i.) They
may be homogeneous in structure — i.e., they may be free from
such defects as blow-holes, which are generally numerous in
cast metals, and from the cinder streaks which produce the
fibre in rolled and forged iron ; the molecules of the several
constituents of which they are composed are then uniformly
distributed ; (2.) The metal may be homogeneous as to strain
— i.e., it may be free from such stresses as are known often
to exist in badly designed castings of brittle materials like
hard cast iron, speculum metal, and in glass.
Defective homogeneousness of structure may be removed,
more or less completely, at any temperature below that of
fusion, by methods specially adapted to use at the given tem-
perature.
Blow-holes are probably due to the presence of air and of
other gases, either absorbed from the atmosphere, as illus-
trated in the " spitting " of silver, or developed by chemical
actions occurring within the mass of metal while in a state of
fusion. This gas can be condensed, excluded or expelled,
either by the mechanical act of compression, or by the use of
some material in the form of a flux, which shall either prevent
the development or the absorption of the gas, or which shall
unite with it, forming a compound which can be separated
by the usual process of skimming the molten metal in the
MECHANICAL TREATMENT OF THE METALS. 519
melting pot, or Which shall, if retained in the mass, be less
injurious than the free gas.
The latter process is illustrated in the use of silicon and
of manganese to confer soundness upon the cast ingots in the
Bessemer and other processes of steel making, and by the
use of phosphorus in insuring soundness in the better class
of copper-tin and of copper-zinc alloys, which metals are very
liable to be made seriously defective by the absorption of
oxygen and the formation of oxide. The bronzes especially,
when rich in copper, are exceedingly liable to this kind of
defect, and the immense increase in the tenacity, ductility,
and other valuable qualities of such alloys, which may be ob-
tained by securing perfect soundness by such removal of the
cause of their unsoundness, has only recently been made gen-
erally known.
The conception of the compression of fluid metals was
probably first introduced by James Wood, a well-known
engineer and mill-wright of Lancashire, England. He used
this process in making printers' rolls of copper, 1856-9, at the
Broughton Works, Manchester, and at the works of J. Wilkes
& Sons, Birmingham. He is said to have shown his method
to Sir Joseph Whitworth.
289. The Whitworth Process.— The mechanical treat-
ment of metal at the point of fusion, for the purpose of
securing homogeneity of structure, is illustrated by the Whit-
worth process of making compressed steel.
In all the usually practised methods of making steel, the
metal is cast in ingots, which are subsequently hammered or
rolled into any desired shape. The steel is sometimes poured
into moulds and given working shapes like cast iron ; the
resulting shapes are known in the market as " steel castings."
These ingots or castings are very liable to contain blow-
holes or air cells, which are produced by the retention, while
solidifying, of occluded air and bubbles of disengaged carbon
monoxide originating in the oxidation of a portion of the
carbon previously united with the metal. The lower the per-
centage of carbon present, the greater the injury produced in
this manner. The use of manganese is resorted to for the
purpose of preventing this " piping ; " but as it is used in the
520 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
form of a carbide, it is usually found difficult to use a sufficient
quantity of manganese in the " milder " steels without, at the
same time, introducing too much carbon. Silicon, also, has
been found to possess the same property in an even higher
degree than manganese. One or two one-hundredths of one
per cent, has been said to reduce liability to such porosity
very greatly. At Terrenoire, France, the double silicide of
iron and manganese, instead of spiegeleisen, is added to the
molten metal as a carburizer.
In large castings and ingots, also, the internal strains, in-
duced by the contraction of the inner portions after the
external part of the mass has solidified, produce serious
weakness, and often crack the whole body of metal to such
an extent as to entirely destroy its value. This is peculiarly
liable to occur in hard steels. Such steels are entirely unfitted
for the use of the engineer in construction ; and such metal
is only used for tools. The " low " steels, on the contrary,
possessing great strength, combined with great ductility, are
the best known metals for constructive purposes. The cast
metal, for the reasons already stated, is usually worthless for
immediate application ; but could it be produced free from
porosity, and as dense as the forged steel, it would have equal
strength and ductility, and would be equally applicable foi
use in structures ; it would also have the important advan-
tages of cheapness and of facile production in any desired
shape. This result is said to have been very perfectly secured
at Terrenoire by the method of fluxing above alluded to.
Whitworth secures this condition by subjecting the fluid
steel to very heavy pressure while contracting and until com-
pletely solidified, by the use of the hydraulic press. A
pressure of 20 tons to the square inch produces all of the
compactness, density, strength and ductility of a forging. By
this method, Whitworth has, in place of worthless metal — as
castings — produced steel of tenacities varying in the several
grades from 80,000 pounds per square inch to 150,000 pounds,
and of ductility varying from 35 per cent, in the softer metal
to 14 per cent, in the strongest grade. Guns made of the
softest grade, when burst, do not fly in pieces as cast guns,
MECHANICAL TREATMENT OF THE METALS.
521
invariably, and even wrought-iron guns very generally, do,
but simply open along the line of minimum strength, and
thus explode with comparative safety to the gun's crew.
FIG. 34. — WHITWORTH'S PRESS FOR INGOT METAL.
Metal shown to the Author by Sir Joseph Whitworth, in 1870,
at Manchester, England, as a product of this process, was
very remarkable for its strength, ductility and homogeneous-
ness, and worked under the tool with most admirable freedom
and uniformity.
Whitworth states that the column of fluid steel, while
solidifying under pressure, shortens an inch and a half to
522 MATERIALS OF ENGINEERING—NON-FERROUS METALS.
each foot of its length. The fact is a good index of the
value of the process, and gives some idea of the degree of
unsoundness of the best of ordinary castings. The change
Enlarged Section through A, A.
Vertical Section. Horizontal Section through B, B.
FIG. 35. — INGOT CAST WITHOUT PRESSURE.
of texture due to compression is very marked, as shown in
the accompanying engravings,* and is readily observed by the
most inexperienced eye. The only special precaution de-
manded in the use of this method is to so arrange the plant
that the molten steel may be put under pressure before
* From Whitworth on Guns and Steel.
MECHANICAL TREATMENT OF THE METALS.
solidification has commenced ; the requisite strength of
moulds must also be secured.*
290. The Lavroff Process. — Bronze and brass may be
treated by the same methods which are seen to have been so
successfully adopted in working steel, and with no less im-
portant gain in excellence of quality. These compositions
are peculiarly liable to defects arising from the occlusion of
gas and by the formation of oxide within the mass. Copper
has a very great affinity for oxygen at high temperatures, and
the very best of copper-tin and of copper-zinc alloys, if made
Transverse Section of Steel Ingot Transverse Section of Steel Ingot
Cast in the Ordinary Way. Compressed while in a Fluid State.
FIG. 36. — INGOT.
without special provision against such injury, are seriously
defective from these causes. The strongest piece of such
composition which the author has ever made, and which far
exceeded in tenacity any gun metal or any other metal
approximating to the same composition, was visibly and
keenly defective. Treatment with phosphorus, or other
oxygen-absorbing element, has been found to do much toward
correcting this fault. Could a perfect absorption of oxygen
be effected, the almost invariable unsoundness of bronze and
* See Report on Machinery and Manufactures at the Vienna International
Exhibition, 1873, by the Author. Washington, 1875. Page 439.
524 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
brass castings would probably be prevented, and what would
now be thought a remarkable combination of strength and
ductility would be secured. Muschenbroeck gives the tenacity
of fine copper wire at about 90,000 pounds to the square inch
(6,327 kgs. per sq. cm.). Cast copper rarely reaches a tenacity
of 20,000 (1,406 kgs). Yet, with maximum density and perfect
purity, the one should be as strong as the other.
Compression with proper fluxing will do all that can be
done toward giving castings of these metals a maximum of
strength, ductility and resilience. Colonel Lavroff, of the
Russian army, has applied the Whitworth method to the
making of cast bronze guns. To make the process thoroughly
complete, it is only necessary that the metal compressed
should have been previously purified by effective fluxing be-
fore pouring.
Col. Lavroff, as stated by Col. Laidley in his ordnance
notes (No. xl., printed by the Ordnance Bureau of the
United States War Department), places the flask, in which
the gun is to be cast, in a pit directly beneath the cylinder of
a hydraulic press. The upper end of the flask is closely
capped by a strong plate of iron, having a cylindrical hole in
its centre. Through this opening a plug of sand is forced
down upon the molten metal by the hydraulic press, and
enters the mass of fluid bronze two inches or more, producing
the required degree of condensation. With such pressures as
are employed for steel, the improvement in the quality of
bronze would be expected to be quite as marked as in that
metal.
291. Rolling and Forging". — Compression and " work-
ing" metal in the solid state, but at high temperature, is the
most usual method of not only giving the materials of con-
struction their shape, but also of improving their valuable
qualities. As is well known to every engineer, all the metals
are found to gain strength with hammering and rolling. The
strength of a grade of iron which has a tenacity of 50*000
pounds per square inch of section, when made into bars two
inches in diameter, becomes gradually increased as the size
of the bar is reduced by rolling, until a one-inch bar of the
MECHANICAL TREATMENT OF THE METALS. $2$
same iron is found to have a tenacity of nearly or quite 60,000
pounds to the square inch. Copper and some of the alloys
may be similarly improved by heating to a moderately high
temperature and drawing out under the hammer, or in the
rolling mill. Cast copper, of a tenacity of 20,000 pounds
per square inch, acquires in this way a strength of 40,000
pounds and upward.
292. Hydraulic Forging and Drop Forging. — This
process is not always effective, however, as large masses, both
welded and cast, are very liable to contain cavities, even after
having been subjected to the most skilful manipulation in the
forge or the rolling mill. The most effective system of ham-
mering is likely to prove inefficient, where applied to large
pieces, in consequence of the fact that the inertia of the mass
attacked will often cause the effect of the blow to be felt only
near the exterior, the internal portions remaining after treat-
ment nearly as spongy and as irregular in structure as before.
The comparatively moderate, but pervading — there is no bet-
ter word — effect of the heaviest hammer, is best adapted to
do such work. The best of all methods of securing thorough
condensation, in the process of forging small pieces which can
be so treated, is that in which the hydraulic press with its slow
action, producing an effect which is felt throughout the entire
volume of the piece, is employed. This process has been well
developed by Mr. R. L. Haswell, at Vienna, and is fully de-
scribed by Prof. W. P. Blake in his report on iron and steel
at the Vienna Exhibition of 1873.*
The process of making forging, with the " drop press,"
which has attained greatest perfection in this country, and in
which the piece is shaped in a die by a single heavy blow, is
also thoroughly satisfactory as applied to small pieces. The
system of hydraulic forging is most economical of power, as
it has been shown by Prof. Kick that the loss of power,
wherever shock is employed in such work, is serious. It is
wasted by dispersion in all directions in the form of heat, due
to compression and to directly produced tremor of molecules,
* Reports of the U. S. Commissioners to Vienna International Exhibition,
1873. Washington, 1876. 4 vols. 8vo, pp. 3, 500.
$26 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
and in the jar and shake which affects all neighboring masses.
The quiet, steady action of the hydraulic press accomplishes
the desired change of form without the latter kind of loss of
energy, and with a minimum loss of power from the produc-
tion of heat by molecular motion.
293. Thermo-Tension and Annealing. — Defects of homo-
geneousness of structure may thus be removed, partially or
wholly, by several known processes of treatment of heated
metal. Defect of homogeneousness as to strain is removable
from iron, and perhaps from other metals, by annealing and
by a method called in 1836, by its discoverer, Prof. Walter
Johnson, " thermo-tension." The metal is heated to a full
red heat, but with great care to avoid a temperature so high
as to give rise to danger of serious reduction of strength by
approaching the welding heat. At this elevated temperature
it is subjected to a tensile stress of as great intensity as is
safe. The metal is then allowed to cool, retaining the stress
applied, and when cold it is released. Prof. Johnson found this
process to confer upon the iron experimented with a maxi-
mum resistance to change of form exceeding, by about 16 per
cent., that which it had originally possessed. He offered no
explanation of the molecular change to which the effect noted
was due ; but it has been attributed by the Author to a release
of internal strains which had previously been introduced by
the irregularly produced flow of the metal occurring during
the processes of manufacture.
Cast metals, glass, and other materials which have been
given form by fusion, casting in moulds and solidification
which so occurs as to produce irregular contraction and a con-
sequent unsymmetrical distribution of metal, and which are,
therefore, found to be weakened by the presence of internal
strains, are relieved of such internal strain by the familiar
process of annealing. The more brittle the material, the more
carefully and slowly must the process of annealing be conduct-
ed. The more ductile the metal and the greater the freedom
with which it is found to "flow" under the action of applied
forces, the less serious are these strains, and the less important
is the process of annealing.
MECHANICAL TREATMENT OF THE METALS.
294. Cold Working. — Metals are worked perfectly cold
in some cases, and the several methods of treatment at the
ordinary temperature may be divided into two classes :
(i.) Those which are practised for the purpose, simply,
of conferring greater density, and of thus securing homo-
geneousness of structure.
(2.) Those which are adopted for the purpose of modify-
ing the character of the metal in respect to internal strains,
and thus of altering the normal elastic limit of the material
by the intermittent application of external forces.
Cold working is illustrated in the processes of wire draw-
ing, cold hammering and cold rolling, simple compression, and
simple extension of metal without heating. The effect of
either of the processes involving compression will assign the
process to the one or the other of the two classes, according
to the nature of the material. It may be that the same
remark will be found applicable to all methods of cold
working.
295. Wire Drawing. — The process of wire drawing is the
oldest and most generally familiar of these methods of treat-
ment of the useful metals. In the manufacture of wire, the
metal is rolled down into rods a quarter of an inch or less in
diameter, which rods are called " wire rods." These rods are
then, in the wire mill, drawn through holes in steel plates, each
of which holes is slightly smaller in diameter than the wire
to be passed through it. As the wire is reduced in size, it
gradually becomes hardened, and, at intervals, the process is
interrupted, and the metal is subjected to the process of an-
nealing to soften it, and thus to enable the decrease in size
to be carried on without the serious loss of power and risk of
breaking which would otherwise be met. As the decrease of
diameter progresses, the wire is found to exhibit a gradual
increase in tenacity, which increase becomes very great when
the wire is drawn very fine.
Brass, and probably all other metals and alloys which
have the requisite qualities to permit them to be worked by
this process, are similarly increased in tenacity by the action
of the draw plate. The precise combination of qualities
528 MA TERIALS OF ENGINEERING— NON-FERROUS METALS.
which best fits metal for making fine wire, has never been
exactly determined. It is not sufficient that the metal have
simple tenacity, or tenacity and malleability, or even duc-
tility, in the unlimited sense in which that term is often ap-
plied. The observations and experiments of the writer have
led him to suppose that perfect homogeneousness of compo
sition, freedom from foreign substances, such as cinder in
iron and oxide in copper and its alloys, and a high ratio of
tenacity to resistance at the limit of elasticity are requisite.
Some metals which have exhibited great strength and also
very great ductility, when tried in the testing machine, have
failed to work well when it has been attempted to draw them
into fine wire. Those irons which have been drawn as fine as
No. 36, or even to No. 40, have usually been marked by a
limit of elasticity much lower than other very fine metals of
equal tenacity and equal ductility as indicated by their be-
havior in the testing machine. No. 40 wire has a diameter
of 0.003 incn = i-i3» or 0.078 millimetre. (See Part II.,
Iron and Steel.)
296. Cold Rolling — The Lauth Process. —As has been
above stated, it . is occasionally necessary to anneal wire
during the process of drawing, as it is rendered too hard to
work without this treatment. This increase in the hardness
of the metal is also accompanied by an increase, equally
marked, in the elasticity of the wire ; and this change in the
character of the material is quite independent of the simple
strengthening which is seen in even the annealed wire. Any
process of compression at low temperature, properly con-
ducted, will exhibit the latter effect. Hammering metal at
the ordinary temperature is sometimes resorted to to give it
an increased hardness and elasticity. The same process is
also practised to confer upon forgings a smooth and hard
surface. If not intelligently executed, this process is liable to
weaken the mass by extending the exterior portions, and
thus straining the inner parts. Where practicable, it is prob-
ably better to use the hydraulic press in doing this work.
A process technically called " cold rolling " has been
adopted to give increased stiffness and elasticity to iron,
MECHANICAL TREATMENT OF THE METALS.
529
steel and other metals intended for certain special purposes, as
for shafting, for the finger bars of reaping machines, and for
other parts of machinery intended to have great stiffness and
very perfect elasticity.
FIG. 37. — EFFECT OF COLD ROLLING.
0 15 30 45 60 75 90 105
The precise temperature at which this effect can be pro-
duced has not been determined. It is within a range which
extends nearly, if not quite, up to a full red heat.* Prof.
Johnson and Mr. Fairbairn found that the cohesion of
wrought iron was practically unaffected at a temperature of
* See Metallurgical Review, Oct. 17, pp. 159-162.
34
53O MATERIALS OF ENGINEERING— NON-FERROUS METALS.
six hundred degrees Fahrenheit, and this may be taken as
evidence that the effect of cold rolling is attainable at tem-
peratures exceeding the black heat.
This process and its effects upon iron have been described
in Part II. The accompanying strain-diagrams, Figure 37, ex-
hibit this effect, and may be taken as illustrative of the effect
of the process on all metals, and especially the bronzes to be
referred to.
297. The Dean Process — Cold Working Bronze has
been practised in the United States by Mr. S. B. Dean, and
in Europe, on a more extended scale, by General Uchatius,
of Vienna. These experimenters endeavored to apply the
process to the manufacture of bronze ordnance, and used the
same general method of adapting it to the work.
This method, as described by the inventor, Mr. Dean, in
1869, is the following: The gun is " placed in a frame, or
upon a bed somewhat like a boring mill for guns, but instead
of using a bar provided with cutters, there is fixed in the end
of the bar a smooth cylindrical plug of hardened steel about
5-100 of an inch larger than the diameter of the reamed hole
in the gun. The plug should be made of two frustra of cones
with their bases connected by a short cylinder.
" For condensing the bores of rifled guns, the plugs used
should have ribs to correspond with the grooves previously
made by the rifling machine.
"The bore being well lubricated, the steel plug is made to
traverse the bore by a screw or other suitable means till it
reaches the bottom of the bore, proper provision being made
to allow air and excess of the lubricant to escape through a
vent in the plug or at the bottom of the bore. Instead of
forcing a plug or plugs from the muzzle to the bottom of the
bore, the condensation may be performed by commencing at
the bottom of the bore and drawing the plug outward ; in
which case the plugs should be so made as to be expansible.
After the first plug has been removed from the bore, two or
more similar plugs are successively forced through, enlarging
the bore to the desired size.
" Care should be taken that each succeeding plug shall
MECHANICAL TREATMEN7 OF THE METALS. 531
have a diameter slightly larger than the one preceding it, and
each plug should perform a slightly smaller amount of com-
pression than the preceding plug, on account of the increas-
ing hardness and density of the bore, which increases the
resistance to be overcome by each successive plug."
Dean found the effect of this treatment to be very marked
in increasing the hardness, strength and density of bronze.
A cylinder of metal taken from the sinking head of a
bronze gun having originally a specific gravity of 8.321, a
tenacity of 27,238 pounds per square inch (19 kilograms per
square millimetre), and a hardness, by the scale used by
General Rodman, of I, was given a tenacity of 41,471 pounds
per square inch (29 kilograms per square millimetre). Its
hardness was increased to 2.97. Its density, in a ring one-
quarter inch thick, next the bore, was made 8.780. In the
innermost thickness of one-eighth inch it was 8.875 ; and the
density of a circular piece one-quarter inch, taken across the
bore, was 8.595. The increase here noted of 50 per cent, in
tenacity by compression has been exceeded by other experi-
menters.
General Uchatius, the director of the arsenal at Vienna,
has reduced this process to practice in the manufacture of
guns for the Austrian army ; and, as he informed the Author
by a note dated June, 1875, the official action of the Com-
mittee on Artillery resulted in the promulgation of the order
that " steel bronze " — the name given by General Uchatius to
the new product — " is to be accepted as gun-metal in the
Austrian army." The process of investigation and its re-
sults are given to the Author by Uchatius substantially as
follows : *
298. Uchatius' Methods of Treating Bronzes. — Ordi-
nary bronze for guns is an alloy, consisting of about 90 parts,
by weight, of copper, and 10 parts of tin. Since the atomic
*See the report by the Author to the President of the United States "On
Machinery and Manufactures, with an Account of European Manufacturing
Districts;" contained in the reports of Scientific Commissioners of the United
States to the Vienna International Exhibition, 1873. According to Volmaer and
others, Kttnzel was the originator of the "steel-bronzes" and deserves more
credit than has been given him.
532 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
weight of copper is 63.4, and that of tin 118, the above pro-
portions of the alloy correspond to a combination of I
equivalent of tin with 17 equivalents of copper. Experiment
shows us that it is questionable whether these two metals
form a chemical compound in these atomic proportions.
When large molten masses of this alloy solidify, an alloy which
is poorer in tin begins to crystallize first where it touches the
mould, its composition being about 92 parts, by weight, of cop-
per, and 8 parts of tin, or I equivalent of tin to 21 equivalents
of copper ; while an alloy richer in tin is pressed from the
former, and solidifies last. This latter alloy, then-, forms in
the inside of the casting, and also enters the cracks which
sometimes form in the outer walls.
This behavior in the fusion of alloys rich in tin was also
noticed in the researches on alloys of copper and tin made by
Alfred Riche.* M. Riche noticed that all alloys of copper
and tin, except those whose compositions correspond to the
formulas SnCu3 and SnCu5, undergo refusion at the moment
of solidification. An alloy richer in tin is separated, so that
different compounds are toJ be found at different points in
the casting. When the alloy consists of tin and copper in the
proportion of I to 5, this refusion occurs to but a slight extent,
but when the composition is different it becomes very serious.
As a proof of the occurrence of these conditions in alloys,
it may be stated that rich bronze of a very homogeneous
character is always found in the smaller parts of bronze cast-
ings ; for example, in the cascabel, or in the trunnions of a gun.
This bronze contains about 8 per cent, of tin, while the body
of the gun is permeated by thin sheets of tin. An 8-inch
tube was made at the Royal Imperial Arsenal, for which
28,000 kilograms (61,600 pounds) of metal were employed.
The greatest diameter of this casting was about 0.84 m. (33
in.), and the proportion of tin at this part was 8 per cent, on
the outside and 12 per cent, on the inside.
Bronze with 8 per cent, of tin has not yet been employed
for guns, because its wear is greater than that of 10 per cent,
bronze. " Gun-metal " has long been employed because of
* " Annales de Chimie et de Physique" tome 30.
MECHANICAL TREATMENT OF THE METALS. 533
its great tenacity and consequent safety, and because it has
the advantage of cheapness and ease in working. Its strength
has satisfied the demand nearly up to the present time, and
it has, therefore, been retained in the manufacture of field-
pieces, in spite of its tendency to " bulge " and to burn out.
Modern practice, however, will no longer permit its applica*
tion as formerly.
From an accompanying table of properties of types of
gun-bronze, we find those of ordinary gun-bronze, as com-
pared with Krupp's steel for guns, to be —
BRONZE.
STEEL.
Tenacity
2,260 kilograms per square
centimetre (32,092 pounds per
square inch).
400 kilograms per square cen-
timetre (5,680 pounds per
square inch).
15 per cent.
12.5 millimetres (% inch).
4,800 kilograms (68,160 Ibs.).
900 kilograms (12,780 Ibs.).
21.4 per cent.
10.5 millimetres (.42 inch).
Elastic resistance
Extension when broken.
Hardness (depth of indenture)
We see that the tenacity as well as the limit of elasticity
of cast steel is almost twice as great as that of ordinary
bronze, which has even less ductility than steel. If the prop-
erties of bronze could not be further improved — wrought
iron being unreliable as gun-metal — we would necessarily be
compelled to accept steel. But, fortunately, new wants are
generally supplied in time by the progress of science and art.
A new modification of gun-bronze, which is much su-
perior to ordinary gun-bronze, according to Uchatius' table
of gun-metals, is now made, for which General Von Uchatius
has proposed the name " steel-bronze," on account of the
resemblance of its properties to those of cast-steel.
If, instead of employing sand, we use iron chills of a cor-
responding thickness of material, the process of solidification
takes place with such rapidity that the alloy rich in tin cannot
separate, and the bronze becomes perfectly homogeneous.
The strength rose to 3,050 kilograms (43,210 pounds per
square inch), the elastic limit remained at 400 kilograms, the
hardness (depth of indenture) at 12.5 millimetres, .5 inch),
while the amount of stretch before breaking, or the ductility
534 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
of the material, rose to 40 per cent. These improvements in
the quality of bronze are a step forward in bronze-casting,
but it is, nevertheless, not sufficient to satisfy modern require-
ments. A gun-barrel cast in this manner would not burst, as
the ductility of the material (40 per cent.) is enormous ; but it
would not be capable of resisting the pressure of the gas ;
and, since the elasticity is not greater than with ordinary
bronze, the gun-barrel would " bulge." The hardness also
remained unchanged, and it is therefore not great enough to
cut the grooves in the sabots of the shot.
General Von Uchatius next tried to roll a piece of the
chilled bronze cold. This could be done, although consider-
able power was necessary. Not the slightest crack was pro-
duced, even when stretched to the amount of 100 per cent, of
its original length. When the bronze had stretched 20 per
cent., it attained the strength, hardness, and elasticity of
steel. The figures are as follows :
The tenacity, 5,066 kilograms per square centimetre,
(71,937 pounds per square inch).
The elastic resistance, 1,700 kilograms per square centi-
metre (24,140 pounds per square inch).
The hardness (depth of indenture), 10.2 millimetres (.41
inch).
It is evident that if this characteristic of chilled bronze,
of assuming the properties of steel, when rolled, could be em-
ployed on the inner surface of gun-barrels, the process would
be of great value. On examining the table of gun-metals,
he remarks the peculiarity that all tough metals assume a
much higher elasticity when they are stretched beyond the
elastic limit, which fact had already been noted by Dean.
In this fact we may find the explanation of a well known
phenomenon, often observed. A bronze barrel which was not
strong enough to resist the charge, and which, therefore,
"bulged," still approximately retained its form after long-
continued use. It could even be reduced, by turning off the
outside, without losing its resisting power. The natural
chilled bronze has its limit of elasticity at 400 kilograms,
(5,680 pounds per square inch), and permits a stretch of 0.0004
ME CHA NIC A L TREA TMEN T OF THE ME TALS. 535
of its length ; while if a permant set of 0.00441 of its length
is produced, its elastic limit becomes 1,600 kilograms (22,720
pounds per square inch), and its stretch within the elastic
limit, 0.00192. The rolled chilled bronze attains its limit
of elasticity at 1,700 kilograms (24,140 pounds per square
inch), and has an elastic extension of 0.0017 of its length,
while a permanent stretch of 0.00018 of its length raises
the limit of elasticity to 2,400 kilograms (34,080 pounds per
square inch) and its elastic extension to 0.00252.
This advantage is as great with steel, wrought iron, and
in general all extensible metals, but it has never been taken
advantage of in the manufacture of guns, until Dean and
Uchatius made the application.
The following principle was enunciated by General Von
Uchatius as a theory of working a gun-barrel from a homo-
geneous, very ductile, and tough metal. It is based upon
results obtained by precise measurements of the properties
of the metals :
I. The work performed by the pressure of the gases of the
exploded powder, and destroying the fit of the shot by enlarging
the bore, should be performed originally by mechanical means,
and to a far greater extent than will be produced by the heaviest
charge. By this means the elastic limit of the metal of the
barrel is increased to such an extent that the smaller press-
ures of gas produced in discharging the gun have no effect.
II. The surface of the bore must be submitted to a process
resembling rolling to such an extent as to give it the necessary
hardness.
By this process of mechanical working of the casting the
material is not overstrained. Its quality is not injured ; on
the contrary, as this extension goes on in the cold state, the
molecules take new and stable positions, refining the metal.
Its properties are, therefore, improved.
Before proceeding to the method of working on the cast-
ing, it was necessary to solve two very important problems,
namely :
Which alloy of copper and tin is best suited for chilled
casting ?
MATERIALS OF ENGINEERING-NON-FERROUS METALS.
How can the quality of the metal at the inside, or nearest
the bore, be made to correspond to that of the alloy at the
outside, so that the metal can be subjected to the* process of
rolling ?
In order to determine the best alloy, a small cast-iron chill
was made, of 25 millimetres (i inch) and 50 millimetres (2
inches) width in the clear, and 25 millimetres (i inch) thick-
ness of sides, into which the following alloys were cast :
12 per cent, bronze.
10 per cent, bronze.
8 per cent, bronze.
6 per cent, bronze.
10 per cent, bronze, with 2 per cent, addition of zinc.
IO per cent, bronze, with I per cent, addition of zinc.
8.5 per cent, bronze, with l/2 per cent, addition of zinc.
The last of these alloys is that which Lavissiere exhibited
at the Vienna Universal Exposition of 1873, and which
attracted attention by its uniform and homogeneous appear-
ance and by its peculiarly excellent quality.
Two rods were cut from each of the castings, and these
were rolled out until they acquired the hardness of " mild "
steel. It became evident, during this process, tha* the 12
per cent, bronze could not bear rolling, and the tests were
limited to the remaining alloys.
It was found necessary to continue the rolling of the rods
in order to reach the hardness of steel ; with the
10 per cent, bronze, to an elongation of 20 per cent. ;
8 per cent, bronze, to an elongation of 30 per cent. ;
6 per cent, bronze, to an elongation of 50 per cent. ;
with the —
10 per cent, bronze and 2 per cent, zinc, to an elongation
of 10 per cent.
10 per cent, bronze and i 'per cent, zinc, to an elongation
of 15 per cent.
8.5 per cent, bronze and l/2 per cent, zinc, to an elongation
of 20 per cent.
The results of tests made can be seen in the following
table :
MECHANICAL TREATMENT OF THE METALS.
537
ALLOYS.
TENSILE
STRENGTH.
ELASTIC LIMIT.
ELONGATION WITHIN
THE ELASTIC LIMIT IN
O.OOOOI.
S
\\
g|
t/i
Pounds per
square inch.
Kilograms per
square centi-
metre.
Pounds per
square inch.
Kilograms per
square centi-
metre.
10 per cent, bronze
7 ',937
73>84°
77,532
42,884
59,214
53>96o
5,066
5,200
5,46o
3,020
4,170
3,800
24,140
19,880
18,460
8,520
14,200
21,300
,700
,400
1,300
600
,000
,500
174
140
128
89
120
*57
i. 5
2.5
3-5
0.5
o-7
i-7
8 per cent, bronze
6 per cent, bronze . . .
ic per cent, bronze and 2 per cent, zinc . .
10 per cent, bronze and i per cent. zinc. . .
8.5 per cent, bronze and % per cent. zinc.
These tests showed that, in general, the 10 per cent., as
well as the 8 per cent, and 6 per cent, bronzes, may be em-
ployed in the new method of making gun-barrels, while the
addition of zinc is of no use whatever, but, on the contrary,
decreases its value in no inconsiderable degree.
The 8 per cent, bronze was judged to be the best for large
castings, and this has, therefore, been taken as the proper
alloy for " steel-bronze."
A number of trials were made to determine what method
of casting and cooling would make the inner layers of the
casting homogeneous, and give the necessary toughness for
standing the treatment to which they were to be subjected.
Simultaneously with these trials, those castings whose
quality was shown to be good, by the appearance of the
fracture, were subjected to the mechanical treatment. A
hydraulic press was employed for this purpose, of a capacity
of 100,000 kilograms (220,000 pounds).
The following is a short sketch of the main features of
the method which was employed for making gun-barrels sub-
sequently to September, 1873:
The castings were 260 millimetres (10.4 inches) thick, 300
millimetres (12 inches) long, having a bore of 80 millimetres
(3.2 inches) diameter. They were conical and turned down at
one end to 180 millimetres (7.2 inches) diameter. They were
then placed vertically under the die of a hydraulic press,
which was then driven through them, in accordance with the
Dean system, a system the earlier existence of which General
558 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
Uchatius seems ignorant. The surface of the die was of well-
hardened steel, and was a slightly-tapering cone, thus
increasing the diameter gradually. But, since the resistance
increased with the enlargement of the barrel, the difference
between the diameter of the plunger and that of the last
formed barrel must decrease gradually. Six plungers were
employed in succession, of which the first increased the bore
by 2 millimetres (.08 inch) and the last by y2 millimetre (.02
inch).
The original diameter of the bore, 80 millimetres (3.2
inches), was thus increased to its normal size' of 87 milli-
metres (3.88 inches) ; that is the increase amounted to 7
millimetres (.28 inch), or 8.75 per cent., while the exterior
diameter of the casting was increased by 2 per cent. The
surface of the bore which was thus produced had a hardness,
when measured by indentation, of 10.5 millimetres (.42 inch),
or equal to that of gun-steel ; it was as smooth as a mirror,
and only needed rifling. It was further remarked that the
same result as to hardness was produced at the end which
was weakened by turning down, which would seem to indi-
cate that the outer layers of guns do not come into play at all
when firing.
299. Experiments on Compressed Bronze. — The mate-
rial of the first two experimental barrels of steel-bronze had
the following properties :
TEST-BARREL NO. I,
TEST-BARREL NO. 2,
NEAR THE —
NEAR THE —
Bore.
Exterior
surface.
Bore.
Exterior
surface.
Tensile strength per i square centimetre, in kilo
grams
4,250
3,320
4,25O
3,320
Tensile strength pe. i square inch, in pounds
Limit of elasticity per i square centimetre, in
60,350
47,H4
60,350
kilograms
Limit of elasticity per i square inch, in pounds ..
Stretch, ultimate, in per cent, of length
Stretcfc, elasMc, in per cent, of length
Section at Ui2 point of rupture, which was orig-
1,100
15,620
16.5
0.306
500
7,100
So
0.060
1,100
15,620
16.5
0.306
700
5°
0.060
inally taken = I.OD
0.56
0.50
0.56
0.50
Hardness, depth of indenture, in millimetres
Hardness, depth of indenture, in inches
10.6
• 42
12
.48
10.6
.42
12
.48
MECHANICAL TREATMENT OF THE METALS. 539
Both barrels were subjected to tests by firing.
These tests were made on the " Simminger Haide," from
40 to 50 shots being fired daily, two shots with the diminished
charge of I kilogramme (2.2 pounds), and 238 shots with the
normal charge of 1.5 kilogrammes (3.3 pounds). The projec-
tiles were 2^ diameters in length, and the powder used for
the charge was large-grained powder, the size of the grains
being from 6 millimetres to 10 millimetres (0.24 inch to 0.4
inch), the density was 1.605.
The barrel showed no signs of either a widening of the
bore or any other flaw after these tests.
The test-barrel No. 2 was tried on the " Steinfelder Haide"
to determine the decrease in precision of firing consequent
upon the firing a great number of shots with the charge of
1.5 kilogrammes (3.3 pounds), and with projectiles 2^2 diam-
eters in length, weighing 6% kilogrammes (14 pounds). The
velocity attained with this charge was 1,480 feet. In all,
2,130 solid shot were fired and twenty shells were thrown.
The examination of the barrel showed the chamber to be
quite unaltered. The enlargement, which was perceptible —
about o.i millimetre (0.004 inch) — was due to burning out
and to mechanical wear. The lands and grooves of the bar-
rel were worn considerably, after this great number of dis-
charges, by mechanical wear and by burning out, but from
the muzzle to the vicinity of the trunnions the lands were
left quite sharp, and consequently were capable of seizing
the projectile with perfect accuracy, giving the necessary
stability in the barrel.
After 2,100 discharges, a projectile was purposely made
to burst in the gun, in order to determine the amount of
damage thus produced and its effect upon the accuracy of fit
of the shot. The following series of 25 shots did not show
loss of accuracy, although the grooves and lands were badly
damaged, for the latter were crushed and the metal squeezed
into the grooves.
This method of working castings applies advantageously
to the production of steel gun-barrels. Steel, having an elas-
tic limit of 2,000 kilogrammes per square centimetre (28,400
540 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
pounds per square inch) and a ductility of 20 per cent., can.
not be produced by any hardening process or method of
manufacture, except by stretching in the cold state.
300. Uchatius' Deductions.— The steel-bronze barrels
will, according to General Uchatius, prove to be better than
those of steel, for the following reasons :
On account of the quadruple price of the steel, and be-
cause old steel-bronze barrels can always be remelted.
On account of the time required in manufacturing, which
with steel is six or seven times as long as that needed with
steel-bronze. In order to produce a cast-steel barrel fitted
with rings, the inner tube is first cast. It is then heated and
worked under the steam-hammer ; it is then bored, and finally
the rings are shrunk upon it. For this purpose are needed,
not only very costly plant, but also skilful, experienced, and
very reliable workmen. The steel-bronze barrels are simply
cast, then bored and pressed, and finally drawn ; all of which
manipulations are very simple.
On account of the greater rapidity of destruction of the
steel by atmospheric influences. The destructive effect of
oxidation rapidly penetrates to the interior with steel, while
steel-bronze merely receives a superficial layer of verdigris,
which does not penetrate.
Because steel barrels are not as safe for the gun's crew
as steel-bronze barrels, of which the exterior layers are so
tough that they must be stretched 50 per cent, before fract-
ure.
The cost of a steel-bronze barrel thus made and of the
size here described is given as $175, and that of a gun made
of steel at $750.
301. Frigo-Tension. — There is, finally, another process —
which is applicable, however, only to ductile iron and steel,
and to such other metals as exhibit an elevation of any nor-
mal elastic limit by the intermittence of strain — which maybe
usefully applied at ordinary temperatures with the result of
increasing the elastic resistance, and, usually, the ultimate
strength of the material. This process has been long used
by bell-hangers when wishing to give wire greater stiffness
MECHANICAL TREATMENT OF THE METALS. 54!
and uniformity of stretch ; but it has not become generally
known or extensively applied in the arts.
When a bar of copper, zinc, tin, lead, or other metal than
iron or steel, is subjected to gradually increasing distortion, it
offers gradually increasing resistance up to the point of rupt-
ure, and this 'resistance follows a regular law in most cases,
whether the distorting force is applied steadily or intermit-
tently. This gradual increase of resistance is due to the fact
that the normal elastic limit for all metals becomes higher as
distortion progresses, until it finally coincides with the ulti-
mate strength of the piece, and fracture then occurs.
When, during the process of extension, the stress is inter-
mitted, the effect of such intermission, as has been seen, Art.
285, is often to produce a marked change in the position of
the normal elastic limit due to the degree of stretch attained,
and it is found that on renewing the effort to distort the
piece, the limit of elasticity, when distortion again begins, is
not precisely where it was at the interruption of the process
of distortion. In some cases the change is hardly, if at all,
observable ; in other cases the elastic limit is found to have
been elevated ; and in still other cases, where the load has
not been removed, it is lowered. This difference has led to
the division, by the Author, of the metals used in construction
into two classes. One comprehends iron and steel, and, pos-
sibly, other metals not yet determined. The other class com-
prehends the inelastic metals, including copper, tin, zinc, and
their alloys.
302. Comparison of Methods.— The effects of the several
methods of working which have been described can be well
explained and illustrated by a comparison of the strain-dia-
grams of the product of each.
The effect of the processes which are adopted to improve
metals by treatment before, or during, solidification after
fusion, is to give greater strength, ductility, elasticity, and
resilience. The strain-diagram is, therefore, given higher
ordinates, a greater maximum abscissa and an enlarged area;
that is, the diagram of the untreated metal is given increased
altitude, an increased extension, and a much greater area.
542 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
The general character of the diagram remains unchanged,
except as to dimensions, unless modified by peculiarities of
subsequent treatment. The effect is the same in kind, to
whichever class the metal may belong. It is the same with
the Whitworth as with the Lavroff process. The treatment
of the molten metal by fluxing before subjecting it to any
mechanical manipulation, produces the same modification of
the strain-diagram. A combination of the two processes, as
the addition of phosphorus to bronze, with compression of the
metal by the Lavroff method, would evidently give a still
more important improvement and would be represented by
a still more marked change in the strain-diagram.
The process of working the metals at a red heat, as in the
rolling mill and in the forge, effects changes which are in gen-
eral exhibited on the strain-diagram by those modifications
which indicate increased strength, ductility, resilience, and
homogeneousness in the character of metals. The effect is
not precisely the same on the two classes. All cast and un-
worked metals give a strain-diagram of approximately para-
bolic form and free from any sudden change of curvature.
Their elastic limits are, therefore, modified by the slightest
distortion, and an elastic limit is found at the zero of load
and of strain. This was first explicitly stated by Hodgkin-
son, when reporting on his experiments on cast-iron. The
strain-diagrams published by the Author in the cases already
referred to * show that this is true of the other cast metals.
The slightest force in all such cases produces a set.
After having been subjected to the action of the rolls or
of the hammer at a red heat, the inelastic metals of Class 2
give the same smoothly curved diagram as before, the change
being observable in the dimensions and not in the form of
the curve. The metals in Class I, however, give strain-dia-
grams which are of a somewhat different form. Instead of
the form O E A, Fig. 38, a sharp change of direction is seen
at some point, and the diagram is more like O E C. The
normal elastic limit of the piece when tested is found to be
at first rapidly elevated as distortion progresses, until at some
* Part II., Fig. 98
MECHANICAL TREATMENT OF THE METALS.
543
point, E, a sharp change of the ratio of the distorting force
to the amount of coincident distortion takes place, and the
sets become approximately equal to the total distortions.
This point is the " apparent " elastic limit, which is the elastic
limit as commonly understood. Rolled or forged metals of
the first class, therefore, have an apparent elastic limit which
is much more clearly marked than in any cast metal, or in
anv metals of the second class.
FIG. 38. — STRAIN-DIAGRAMS.
Thus, in Figure 38, let the curves A, B, and C represent
the strain-diagrams, (i) of any cast metals, (2) of a rolled
metal of the second class, and (3) of a part of the diagram of
rolled iron, respectively. The characteristic differences be-
tween the two rolled metals and between them and the cast
metal are well indicated. These curves are copied from actual
diagrams produced automatically, and are real graphic repre-
sentations of those characteristics.
The depression seen at D is an indication of the presence
of fibre in the metal.
303. The Effect of the Processes of Rolling and of
Hammering the metal cold are graphically represented in
•Figure 39. The strain-diagram A is a copy of the beginning
of that given in the Mechanical Laboratory of the Stevens
• Institute of Technology by a piece of merchant bar iron of
excellent quality. That marked B is a copy of the initial
544 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
portion of a diagram produced automatically by a sample of
cold-rolled shafting made by treatment of a piece of iron
of similarly good quality.*
It is seen at a glance that the effect of cold-rolling is, in
this case, to bring the apparent elastic limit nearly up to the
maximum of resistance, which is only attained in the un-
treated metal after very great distortion. As has already
been stated, the piece also exhibits a much greater ultimate
FIG. 39.— STRAIN-DIAGRAMS OF IRON.
resistance than the same metal prepared in the usual way.
The resilience, taken at the elastic limit, is immensely in-
creased, and the elasticity of the metal was found to be the
same, wherever measured, while distortion was progressing.
The metal is probably compacted to some extent, but to so
slight a degree that the resulting change of density has not been
measured.f Examining the piece after fracture, it is found
that concentric layers differ from each other in the degree in
which they exhibit the effect of cold-rolling, but that in each
layer the metal is rendered exceedingly homogeneous. As in
all ordinary work the metal is never intended to be perma-
*See plate, above referred to, Part II., strain-diagram No. 85; see also
Report by the Author on an extensive series of tests of cold-rolled metal for the
American Iron Works, 1877.
f Major Wade found no increase of density, but apparently a slight decrease
after cold-rolling iron.
MECHANICAL TREA TMENT OF THE ME TALS.
545
nently distorted — is never expected to be subjected to strains
which can produce permanent set — the increased value for
constructive purposes which is conferred by this treatment is
measured by the increase noted in its strength, elasticity,
ductility and resilience within the elastic limit. It is seen to
be immensely great. The effect observed is, in this case, due
probably to the elevation both of the apparent and the nor-
mal elastic limit, by both the simple condensation and in-
crease of homogeneousness which occurs with metals of the
FIG. 40. — STRAIN-DIAGRAMS OF BRONZES.
second class, and by that peculiar exaltation of tenacity, by
some as yet not fully determined change in molecular rela-
tions, which is only known to take place with metals of the
first class.
The effect of the cold-rolling process is, however, the
same in kind, so far as it affects the form of the strain-dia-
gram, where the second class of metals is treated, and the
curves seen in Figure 40 are copies of diagrams produced
automatically, during the tests of two pieces of bronze from
an old gun. The diagram A was given by a test piece
taken from the exterior of the gun, where it had been little,
if at all, affected by the compression ; and that marked B was
given by a specimen taken from the inside of the bore, where
the effect of compression was most marked.
On comparison, it is seen that the effect of the process of
35
MATERIALS OF ENGINEERING— NON-FERROUS METALS.
compression, at the ordinary temperature, of both classes of
metal is the same in kind. So far as it affects simply the re-
lation of the distorting force to the distortion produced by it
in each, the result of the operation is the elevation of the
limit of cohesion by condensation of the metal and by the
production of greater homogeneity. In the case of iron and
steel, the effect of this treatment is heightened by the pecu-
liar property of those metals which has been already fully
described. With both, the result of cold working is highly
advantageous for many purposes. In some cases — as, for ex-
ample, when the metal is to be subjected to extremely violent
shocks, and is therefore likely to be permanently deformed,
and where it should be capable of offering a maximum resili-
ence up to the point of actual rupture, e.g., the armor-bolts
of an iron-clad — the metal should not be subjected to this
process, or should be treated very cautiously. Where great
strains are liable to be met, but without impact, as in the more
usual applications of such metals in machinery, and as in
ordnance, where the tremendous pressures exerted are due
only to the elasticity of a confined gas, it is as evident that
cold-worked metals are well fitted to give a maximum resist-
ance without counterbalancing disadvantages.
304. Historical — Discovery of Facts and Determination
Of Laws. — It is impossible to say just when all the facts and
laws above given were first known. The first intelligent
statements of the simpler facts were made, probably, by
Galileo, who, in 1656, published a work — " Opere di Galileo"
— at Bologna. Robert Hooke, in 1676 and 1678, was the
first to announce the important principle which forms the
basis of our theory of elasticity of bodies within the elastic
limit, in the now celebrated Latin phrase, ut tensio sic vis —
the extension is proportional to the force. Marriotte, Leib-
nitz, Parent, Bernouilli, and other mathematicians, discussed
the theories of flexure and of rupture of beams with equal
mathematical skill and practical ignorance. Coulomb, about
a century ago, gave the best mathematical treatment pub-
lished up to that time, and made some experiments which
were of real value. Dr. Thomas Young, the ablest writer
MECHANICAL TREATMENT OF THE METALS. $4?
wKo lias ever devoted a mind rich alike in scientific knowledge
and in power of useful application, to practically valuable
study, defined the modulus, or coefficient, of elasticity, and
reduced to practical shape the laws enunciated by Hooke
and other earlier writers. Dr. Young also defined the quality
which Professor Lewis Gordon afterward called, " resilience,"
and showed that it measured the amount of "work" done in
distorting a body.*
The first connected and special treatise on strength of
materials, and on construction, was the work of the dis-
tinguished Navier, the lecturer at the &cole des Fonts et Chans-
sSes, in 1824 ; but Tredgold had already prepared his excellent
treatise on iron. Since then, Fairbairn and Hodgkinson,
Morin, and many others, have written valuable treatises on
the subject, or upon special divisions.
Probably the most reliable and extended of early re-
searches in this field were the experimental investigations of
Muschenbroek, of which an account is given in his Introduc-
tion to Natural Philosophy, published in 1762. Banks, in
1803, anc* Rondelet, in his "Art de Batir" 1814, published
the results of experiments on iron. The best work which has
since been done has been published within a few years by
Fairbairn and Hodgkinson, Kirkaldy, Styffe, Bauschinger,
Wohler, and by our own countrymen, Rodman, Wade,
Shock and some other experimenters in special directions.
The fact of the existence of an elastic limit was very early
discovered. Duleau, in his ^ Essai Thtorique et Experimental
sur la Resistance du Per Forge" printed in 1820, gives the
elastic limit of that metal as at 8,540 pounds per square inch,
and at an extension of about 1-3333 °f the original length of
the piece in tension. Tredgold, writing in 1823, says: UI
find that while the elastic force, or power of restoration,
remains perfect, the extension is always directly propor-
tional to the extending force, and that the deflection,
does not increase after the load has been on for a second or
two ; but when the strain exceeds the elastic force, the ex-
tension or deflection becomes irregular and increases with
* Thomson and Tait; Nat. Philos , vol. i., part ii., p. 228.
548 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
time." Coulomb had already, many years before, noticed
that many materials take a permanent set long before the
breaking point is reached, and Emerson had, as early as 1758,
asserted that the materials of construction should not be sub-
jected to a force exceeding from one-third to one-half their
ultimate resistance, and thus proposed the now invariable
practice among intelligent engineers of taking a certain
" factor of safety." In Tredgold's time, also, the work of
Telford, Brown, Rennie, Barlow, and Rondelet, was well
known. The fact that the elastic limit of a piece of metal
exceeds its primitive value more and more as the piece is
more and more distorted, was exhibited by some of the very
earliest of these experiments. Dr. Young, in 1807, made the
fact the basis of his remark: "A permanent alteration of
form limits the strength of materials with regard to practical
purposes, almost as much as fracture ; since, in general, the
force which is capable of producing this effect is sufficient,
with a small addition, to increase it till fracture takes place."
(Nat. Phil., vol. i., p. 141.) He also pointed out the impor-
tance of the determination of the resilience of a piece as a
measure of its power of resisting impact. Tredgold gives,
1823, simple rules for the application of this principle, and
both indicate the necessity of noting the variation of the re-
sistance as distortion progresses in order to obtain a measure
of that resilience.
305. Experiments published in 1840, in the Phil. Trans-
actions, by Hodgkinson, were the fiist to supply data for an
exact determination of the method of variation, and of the
values of the normal elastic limit from the instant of its de-
parture from its primitive value. His work is still quoted as
standard authority, and as the most extended as well as
thoroughly precise series of experiments yet made. His
later work, extending over several years, is no less valuable.
His tabulated results of test showed that sets occur with very
light, if not under all, loads ; that the sudden change which
marks what is here termed the apparent elastic limit, is
followed by a gradual elevation of the limit as distortion
proceeds, and that the normal elastic limit has a value, for
MECHANICAL TREATMENT OF THE METALS
549
each stage of distortion, which may be expressed by formulas
of the kind already given. The fact was shown that the in-
crease of resistance, as change of form occurred, became less
and less marked up to the maximum.
Clark, in his account of the Britannia and Conway bridges,
in 1850, makes the statement, based on results obtained by
Hodgkinson and himself: " We have seen that as we increase
the permanent set of wrought iron we diminish the subse-
quent extension and compression from any load, and we
have alluded to the fact that the tubes would have deflected
less from any given load if the top and bottom had been
previously compressed and extended by any artificial strain.
It follows from this consideration that if the compressed and
extended portion of a wrought iron bar could be, by any
artificial means, permanently strained previously to its em-
ployment as a beam, such a beam would deflect less than a
new bar, and would be practically a stronger beam, since the
strength is regulated solely by the bending of the bar." This
is probably the first time that such a statement was made of
this now well-known and very important principle. Long
after, few engineers were aware of the fact that it was then
so distinctly enunciated and that the discoverer determined,
by direct experiment, the effect of this method of treatment.
Clark gives the tabulated results of test of bars thus
treated, beside those derived from the test of other bars left
in their original state. The former deflected but 1.765 inches
under a load of 46.5 hundredweight ; while the latter de-
flected 5.145 inches under a load of 41.9. The bars were \y2
inches square and the supports were 3 feet apart.
Werder, at Munich, in 1854, used tie-rods which, by a single
effort of tension, had been similarly stiffened. Neither
Clark nor Werder seems to have understood the peculiar
phenomenon of the exaltation of the normal elastic limit by
intermitted strain, or to have availed himself of it by re-
peating the efforts of distortion.
Later experiments made at the Woolwich dockyard ex-
hibited another interesting and important phenomenon due
to the same characteristic. A rod was broken several times
550 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
in succession, and exhibited continually increasing ultimate
resistance. Other rods similarly treated gave the same re-
sult. The mean of 10 gave a tenacity at the first fracture of
24.04 tons per square inch ; the means of succeeding breaks
were at 25.94, 27.06, 29.20, while the extension varied too
irregularly to indicate any law. Simitar experiments have
since been made in 1873, by Bauschinger and other experi-
menters. It was at first generally supposed that the last
noted behavior of iron was due to the obvious fact that the
bar must have broken at the weakest point first, at the next
weakest place next, and so on, until the last fracture occurred
at very nearly the section of maximum strength of the bar.
It is now, however, evident that it is, or may be, due partly
to the action noted by Clark, and also that it may take place
in metals of both the classes which have been above defined
by the writer. In the iron class, however, the effect is un-
doubtedly more marked than in metals of the tin class, since
there the exaltation of the normal elastic limit also comes in
to increase the resisting power.
306. The Exaltation of the Normal Series of Elastic
Limits by intermittence of strain and by lapse of time at a
constant distortion, was observed by the Author in 1873.
Commander L. A. Beardslee, U. S. N., independently noted
the same phenomenon, later in the same year. The latter
has since determined the magnitude of this change in iron
during periods varying from one second to one year. (See
Part II., Art. 298.) The Author, at about the same time, ob-
served the depression of the normal series of elastic limits
in the inelastic metals.
As early as 1858, Prof. James Thomson, who had seen the
importance of the property which produced the variation of
resistance of materials between their primitive elastic limits
and their ultimate fracture, and had called it u viscosity," had
shown its effect in modifying the mathematical expressions
deduced for the torsional resisting power of metals. He
pointed out the marked difference in the forms of these
formulas where applicable to brittle and to ductile, or viscous
metals, and, in the latter case, to the resistance within and
MECHANICAL TREATMENT OF THE METALS. 551
beyond the primitive elastic limit. Almost nothing has,
however, been since done in the further modification of work-
ing formulas with reference to the position and variation of
the normal elastic limit, or to the determination of actual
resistance, except that the Author has applied the same proc-
ess to the modification of formulas for transverse resistance of
tough metals, and independently of Prof. Thomson, but many
years later, to the general case of torsion and to the inter-
mediate condition in which a part only of the section is
strained beyond the primitive elastic limit.
M. Tresca and Captain Beardslee have shown, as has the
Author (1873-83), all working independently, that, with iron,
the variation of the normal elastic limits may extend nearly
or quite up to the point of actual rupture, and that the mod-
ulus of elasticity remains almost unchanged. The Author,
experimenting with all the common materials of construction
and with the whole range of alloys of copper-tin and copper-
zinc and with the copper-tin-zinc alloys, has found the same
to be true.
Fairbairn, who was thoroughly familiar with the behavior
of iron under strain, supposed the increase of resistance with
distortion to be a consequence of the gradual bringing into
action of particles in bodies which are not homogeneous as
to strain, as the fibres of a rope are brought gradually into
tension as the rope is more and more stretched. The Author
has proposed a very similar explanation of the exaltation of
the normal elastic limit by intermitted strain, and has shown
how such a condition may be produced by the process of
manufacture of those metals which exhibit that phenomenon
most strikingly, but does not regard it as a satisfactory ex-
planation of the kind of variation of the elastic limit which is
observed in both classes of metals alike, to explain which it
was offered by Fairbairn.
Kick has (1870-80) shown the increased resistance of soft
bodies attacked by shock, and confirms the deductions of the
Author in that respect.
307. Strain-Diagrams. — Gen. Morin was probably the
first, about 1850, to represent the relation of the distorting
552 MATERIALS OF ENGINEERING— NON-FERROUS METALS,
force to the amount of distortion by the graphical method,
and, in his "Resistance des Materiaux" plotted beautifully the
results of Hodgkinson's experiments. His curves exhibit
perfectly the characteristics of the metals, the tests of which
they represent, and exhibit plainly and accurately the
variation of the elastic limit by continued strain. They
do not, of course, indicate the exaltation of the normal limit
by intermitted strain. Mallet, in 1856, uses the same curves
to illustrate his application of the principle of the equivalence
of the work done in producing fracture of the materials used
in the construction of ordnance with the resilience of the
metal, and the vis viva of the shot or other mass attacking by
impact. Gen. Rodman, Major Wade, Kirkaldy, Styffe, and
other later experimenters, have used the graphical method
during the last quarter of a century in illustrating nearly all
their work. In all such strain-diagrams, the variation of
the elastic limit is exhibited, and the law of its variation
with gradual change of form is expressed. Rodman was the
first investigator to adopt the method as a system, using it in
his report on his experiments on metals for cannon made in
1856 and 1857.
Finally, the Author, in 1873, observed the exaltation of
the normal series of elastic limits as recorded on automatic-
ally produced strain-diagrams, and gave an account of that,
and of other interesting phenomena exhibited by the auto-
graphic strain-diagram.
308. History of Processes of Working Metals. — Re-
verting to the several processes of working metals which have
been described, it will be seen that the methods of securing
improvement by an increase of homogeneousness by treat-
ment of the metal while fused, have no relation to any other
modification of the elastic limit than that which distinguishes
a structurally weak and defective material from a more per-
fect specimen of the same metal. The processes of cold-roll-
ing and of other methods of compression of cold metal in-
volve, whether the metal be iron, steel, bronze or brass, that
form of variation of the elastic limit which has been known
since the time of Tredgold, and possibly of Muschenbroek,
MECHANICAL TREATMENT OF THE METALS.
553
in addition to the change produced by the condensation of
solidifying metal, and in a marked degree. The ordinary
processes of working metal hot are intermediate in character
between the other two. It is seen that the iron class, whether
worked hot or cold, experiences, besides, a change which the
writer has proposed to denominate the " exaltation of the
normal elastic limit by intermitted strain." It is seen that
the latter action is not involved in the cold-working of
bronze.
Internally Cooled Iwrot.
Coat Ingot.
FIG. 41. — INGOTS.
In securing homogeneousness of structure by treatment of
the molten metal, various methods of fluxing have been prac-
tised from an unknown and very early period. The most suc-
cessful methods have involved the use of phosphorus as a
flux in casting bronze and of the silicide of iron and man-
ganese for iron and steel. The method of compression of
molten metal at the point of solidification was first brought
into use by Sir Joseph Whitworth, of Manchester, England,
about 1860. It was subsequently adopted on the Continent
of Europe, and is now becoming well recognized as one of
the most efficient known methods of producing metal of the
highest possible grade. This method was first applied to the
554 MATERIALS OF ENGINEERING— NON-FERROUS METALS.
production of bronze guns by Colonel Lavroff, in the Russian
arsenals, about 1867. By him the process was perfected in
1870.
Chill-cast bronze was probably first proposed by Mallet in
1856, and he at the same time proposed the use of a hollow
core to be cooled by currents of air, as in Figure 41. This
method was adopted with great success by makers of bronze
a few years later. It was adopted by General Uchatius in 1873,
after having seen the remarkable success of M. Lavissiere,
who exhibited a bronze gun made in this way at the Vienna
Exhibition of that year. Colonel Rosset, of the Italian artil-
lery, had also adopted the same method, and it is referred to
in his work, " Esperienze Meccaniche sulla Resist enza dei Priti*
cipali Met alii da Bocche da Fuoco. Torino, 1874," in which
he also recommends the adoption of the Dean method of
making bronze guns.
The form of chill used for ordnance is shown on a subse-
quent page.
The ordinary methods of forging and working metals at a
red heat were introduced hundreds of years ago, and their
early history is quite unknown. Rolling mills for working
iron were introduced about 1784 by Cort, the inventor of the
process of puddling.
Wire was made by hammering by the ancients and at a
date which is not known. Wire drawing was invented 500
years ago, in Nuremberg, Bavaria, by a " wire-smith " named
Ludolf. By the middle of the seventeenth century the busi-
ness of wire drawing had been imported into Great Britain,
and was employing thousands of people in England and in
Germany. In 1813 Dr. Wollaston introduced his method
of enclosing one metal within a bar of another metal and
drawing down the two together. When finished the outer
coating was dissolved off by an acid, and the inner and ex-
tremely fine wire was left perfect. Platinum wire has been
thus made, by enclosing it in silver, of but i-3O,oooth inch
diameter. Mr. Brockedon, as early as 1819, using the pre-
cious stones as draw-plates, produced wire 0.0033 inch in
diameter.
MECHANICAL TREATMENT OF THE METALS. 555
309. Cold-working Iron, as a system, has been prac-
tised but a comparatively short time. It had long been
known that such treatment imparted stiffness and elasticity
to metals, but it was not known at what stage of the process
of condensation, if any, the action ceased to produce benefit
and became liable to injure the metal by weakening it by the
introduction of internal strains. It was well known to ex-
perienced engineers and metal workers that cold-hammered
iron, and iron rolled cold, was often seriously injured by being
worked too cold ; and the Author was accustomed, many
years ago, to give special instructions to the smith who was
about to make the forgings of a steam engine which were
to be left without tool finish, not to attempt to give them the
fine finish under the hammer which may be given by hammer-
ing at a " black heat," lest they should be weakened by the
treatment. It was not then generally known that cold-work-
ing might be so conducted, and safely, as to secure an in-
crease of strength.
The process of cold-rolling was introduced in the United
States by its inventor, Bernard Lauth. His experiments were
first made in 1854, and in 1857 he fitted up a set of rolls for
systematic experiment ; and in January, 1858, he brought out
cold-rolled iron as an article of manufacture. Two other in-
ventors, Messrs. Cuddy and Savory, invented very similar
processes almost simultaneously with their successful rival
Lauth. Mr. Lauth was assisted pecuniarily, and by the prac-
tical knowledge of, Mr. B. F. Jones, and the work was done at
the mills of the American Iron Works, Pittsburgh. The proc-
ess was introduced into Great Britain by Lauth in 1858. He
introduced it into France and Belgium in the following year.
The process has now become one of the well-established
methods of iron-working, and is gradually becoming recog-
nized as a valuable method of modifying the properties of
steel, bronze, and other metals.
As applied to iron and steel, it evidently results in the
strengthening of the metal by condensation and by the pro-
duction of greater homogeneousness of structure, and also
gives stiffness and elasticity by the long-known form of ele-
556 MATERIALS OF ENGINEERING— NON-FERROUS METAL&
vation of the primitive elastic limit, as well as by the exalta-
tion of the normal limit by the action ascribed by the Author
to intermitted strain. As applied to gun-bronze and other
metals of the tin class, it produces its useful effect only by
the first two methods of change.
310. Cold-working Bronze and that class of metals by
Mr. Samuel Buel Dean, of Boston, Mass., was applied by him
to the improvement of gun-bronze at some time previous to
1859, at which date he laid his plan before the ordnance
officers of the United States War Department,
and illustrated its effects by treating samples of
gun metal, as has already been described. The
Ordnance Bureau ordered guns to be made by
the, Dean method in July, 1870, and the work
was subsequently interrupted in consequence of
the neglect of Congress to vote the necessary
funds. In Great Britain, the Committee on Field
Artillery for India, in 1870, reported in favor of
the adoption of this method.
General Uchatius, of the Austrian artillery,
adopted the process in 1873, using the method
of condensation described in the patent of the
inventor, Dean, which had been filed in Vienna
July 1 6, 1869, in Register sub-vol. xix., fol. 378.
The British and French patents were dated May
10 and May 12, respectively, of the same year.
The United States patent was dated May 18.
FIG. 42.— CHILL Uchatius adopted the method of chill-cast-
FOR ORDNANCE. ing SUggested by Mallet in his work " On the
Construction of Artillery," as has already been stated. The
first information given abroad relating to the Dean process
was probably the statement made by Mr. Clemens Herschel
to Mr. Isidor Kanitz, of Vienna, May 18, 1869.
The following figure represents Dean's apparatus. The
metal cylinder to be strengthened, A, is supported by a cast-
ing, B, while the rod, C, carrying the mandrel, is driven
through it.
The adoption of the process invented by Dean, by the
MECHANICAL TREATMENT OF THE METALS. $$?
Italian military authorities, was advised by Colonel Rosset
also, and is referred to in his work on gun
metals, published almost simultaneously with
the description, by General Uchatius, of the
details of the method of application of the
Dean process in the Austrian arsenal.
311. Conclusions. — The processes which
have been described at such length in the pre-
ceding pages are regarded as the most important
known processes of modification of the primary
, . . r , , f , FIG. 43.— COLD-
qualities of the useful metals. WORKING
It may be concluded, from what has pre- BRONZE.
ceded, that the proper method of preparation of metal to
secure a maximum value is the following:
(i.) Reduce the metal, when possible, to the molten con-
dition, flux thoroughly with such a flux as will remove, first,
all deleterious substances with which the metal may be con-
taminated ; secondly, every particle of gaseous oxygen and
of oxide ; and, thirdly, all other occluded gas liable to pro-
duce "blow-holes."
(2.) Cast the metal under heavy pressure, in order to
secure maximum density and to close up every pore as per-
fectly as possible. If the metal is an alloy which is liable to
liquation, it should be cast in a chill of sound iron and of
considerable thickness.
(3.) If the metal is either iron or steel, produce any con-
siderable change of shape which may be desired by rolling,
by the drop-press, or by hydraulic forging at a full red heat,
and permit it to remain unused as long as is possible, in order
that the internal strain, unavoidable to some extent with any
method of treatment, may be given time to become reduced
by that process of flow which will ultimately relieve it. If
stiffness and a more perfect elasticity are demanded, finish
by the process of cold-working, taking great care not to carry
it so far as to seriously injure the continuity of the metal.
(4.) The bronzes, and other metals of the inelastic and
viscous class, may be given very considerable modification
of form by the processes of working cold. The same precau-
558 MATERIALS OF ENGINEERING-NON-FERROUS METALS
tion must be taken to avoid destruction of continuity, and
thus, by the . production of incipient fracture, permanently
and seriously injuring it.
By observing these precautions, the maximum value of the
metal for constructive purposes may be attained. Whitworth
has made " homogeneous iron " castings having a tenacity of
35 tons per square inch by his process, and the Author has
made brass without any special treatment, either by fluxing,
compression, or other modifying processes, having a strength
of 70,000 pounds per square inch (4,921 kgs. per sq. cm.) It
is not unlikely that the theoretical maximum for any material
— the maximum due to the effort of the force of cohesion,
and that which is perhaps approached, in special cases, in
fine wire — may be nearly attained, even in large masses, by
the skilful and intelligent combination of the processes which
have been here described in the treatment of such cast metals,
and in their adaptation to purposes of construction.
APPENDIX.
§ 51, p. 90. — Aluminium and zinc in the proportions 67
and 33 give an alloy of much value for special purposes.
From a series of tests made in the Mechanical Labora-
tory of Sibley College, on the strength of alloys of alumin-
ium and zinc in varying proportions, the best results were
found for mixtures of not far from the above proportion.
The principal properties of the metal were found to be as
follows :
Tensile strength deduced from small bars 22,000
Maximum "• fiber stress" deduced from transverse tests. 44,000
Modulus of elasticity 8,000,000
Specific gravity 3.3
Apart from the above, comparative experiments have been
made more recently between small bars of this metal and
like bars of cast iron, showing the same general indications,
and apparently warranting the conclusion that this alloy is
the equal of good cast iron in strength, and its superior in
location of elastic limit. The other general physical prop-
erties of chief interest are as follows :
The color is white and it takes a fine, smooth finish and
does not readily oxidize. It melts at a dull red heat or
slightly below, probably about 800-900 F. It can, therefore,
be readily melted in an iron ladle, over an ordinary black-
smith's forge or other open fire. It is very fluid and runs freely
to the extremities of the mould, filling perfectly small or thin
parts. In this particular it is much superior to brass. It
does not burn the sand into the casting, and hence comes out
clean and in good condition to work, It is rather softer and
more easily worked than ordinary brass, and yet is not as
liable to clog a file. It is brittle like cast iron, and hence is
560 APPENDIX.
u-
not suited to pieces which require the toughness possessed
by brass. For equal volumes and with aluminium at 50 cents
per pound, it is about equal in expense to brass bought at 15
cents per pound. It becomes ductile at 212° F.
This alloy would seem to be admirably adapted to many
small parts of machines, models, etc., where it is desired to
obtain castings without waiting for a regular foundry heat,
and where lightness combined with good finish, strength,
stiffness, and non-corrosiveness, are among the desiderata. It
has been employed with great success in the construction of
small screw propellers for experimental work.*
According to Hunt, zinc is used as a cheap and very
efficient hardener of aluminium castings for such purposes as
bicycle frames, sewing machines, etc. Proportions up to
30 per cent, of zinc with aluminium are being successfully
used; an alloy of about 15 per cent, zinc, 3 per cent, tin,
and 82 per cent, aluminium having especial advantages.
Copper in proportions of from 2 to 15 per cent, has been
advantageously used to harden the metal in cases where a
more rigid metal is required than pure aluminium. Copper is
the most common metal used at present to harden alumin-
ium. A few per cent, of copper decreases the shrinkage of
volume, and gives alloys that are especially adapted for art-
castings.. The remainder of the range, from 20 per cent,
copper up to 85 per cent., give crystalline and brittle alloys
of no use in the arts, which are of grayish-white color, up to
80 per cent, copper, where the distinctly red color of the
copper begins to show itself.
Aluminium brass has an elastic limit of about 30,000 Ibs.
per square inch ; an ultimate strength of from 40,000 to
50,000 Ibs. per square inch, and an elongation of 3 to 10 per
cent, in 8 inches.
An alloy of 70 per cent, copper, 23 per cent, nickel, and 7
per cent, aluminium has a fine yellow color and takes a high
polish, a small percentage of phosphorus in phosphor-tin
hardening the alloy considerably.
* Science \ vol. v., No. 114.
APPENDIX. 5l
Tin has been alloyed with aluminium in proportions from
I up to 15 per cent, of Sn., giving added strength and rigidity
to heavy castings, as well as sharpness of outline, decreasing
the shrinkage of the metal. The alloy Al. 50, Sn. 25, Zn. 25
has a tenacity of 20,000 pounds and 8 per cent, elongation.
§ 54, p. 95. — " Magnesium as a Constructive Material " *
is as yet little known, but its properties indicate large possi-
bilities- Weighing but two-thirds as much as aluminium, and
between one-fourth and one-fifth as much as iron or steel, it
seems likely to find uses in the arts, and, like aluminium, par-
ticularly in the alloys.
The following are its physical constants :
PROPERTIES OF MAGNESIUM.
Specific gravity i . 743 (109 Ibs. per cu. ft.).
Specific heat ; o. 2499.
Atomic weight 2394.
Melting point 433° C., 8n° F.
Boiling point 800° C., 1472° F.
Electric conductivity 41.2.
Tenacity per sq. in 22,000 to 32,000 Ibs.
Compression resistance 37,ooo Ibs.
Bending modulus 23,750 Ibs.
Length sustainable 28,000 to 42,000 ft.
Its flame has a temperature of about 1,340° C. (2,444° F.),
but the light is similar to that of an ordinary flame at three
times this temperature. Its radiant light energy is 13.5 per
cent. — a higher figure than that of any other known flame,
constituting three-fourths its total energy of combustion and
four times that of illuminating gas. Its total light-giving
efficiency is 10 per cent., as against one-fourth of I per cent,
for gas ; and taking into account the greater luminosity of its
light rays, it has fifty or sixty times the value of gas. Its
spectrum is nearer that of sunlight than that of any other as
yet discovered artificial illuminant.f
Magnesium is usually obtained by reduction from fluor-
* Mainly from paper, by the author, of similar title ; Machinery, May, 1896.
f See papers of Professor Nichols and of Mr. Merritt : Trans. Am. Inst.
Electrical Engineers, 1890-91.
36
$62
APPENDIX.
spar with sodium, but it may also be reduced by the electric
arc, like aluminium, and it is very possible that, once its valu-
able properties and possible applications have attracted
attention, it may be produced in quantity very cheaply.
It is quite easily distilled and may be thus purified suc-
cessfully. The spectrum indicates a close relation between
magnesium and aluminium ; both giving bands in the yellow
and green, of which those of the former are noticeably duller
than those of the latter.*
The following are the results of test of the commercially
pure metal in form of wire.f The strength here obtained is
but about two-thirds tnat given by authorities generally, as
quoted above :
PROPERTIES OF MAGNESIUM.
Specific Gravity, 1.74 ; Melting Point, 446° F., 230° C".
NO. OF SAMPLE.
DIAMETER,
INCHES.
ELASTIC
LIMIT, LBS.
PER SQ. IN.
BREAKING
LOAD.
DUCTILITY,
PER CENT.
MODULUS
OF ELAS-
TICITY.
J
O 433
8 800
23 8OO
A 2
2 040 OOO
O.433
10 780
22 050
I 88O,OOO
O 442
8 400
2O QOO
i 8
2 060 OOO
4
0.435
7,000
I9,5OO
2.5
I,83O,OOO
O.424.
24. 8OO
o . i
I Q3O OOO
6
O 4.32
22 5OO
2 a
8,770
22 250
2.8
I,945,OOO
Best figures
10 780
23 8OO
4. 2
2 060 OOO
Tests of cast magnesium have given results averaging
about one-half the above, and ranging from 9,640 to 13,685
pounds on the square inch. The figures given in the table
as the best may, perhaps, be taken as those most closely
representing the qualities of a pure metal of maximum den-
* See a paper on " Materials of Aeronautic Engineering," by the writer, in
Transactions of the Aeronautic Congress, 1893 ; also Aeronautics for March, 1894.
In these studies all materials were compared by deducing from the data obtained
the length of their own substance which each metal could sustain. Steel, for
example, when of 75,000 pounds tenacity, would carry about five miles of straight,
suspended bar.
f Published in the Sibley Journal of Engineering, January, 1894.
APPENDIX.
sity and purity, and better than can usually be expected in
commercial work. They constitute a standard to which
specifications may perhaps gradually approximate. The pure
metal thus greatly excels pure aluminium in tenacity.
Copper and magnesium have not been found to alloy,
although much time and labor have been expended in the
endeavor to secure such compositions.
Brass will take up a minute proportion of magnesium,
but with no sensible useful result. The presence of the
lighter metal produced neither accession of strength nor
increased tenacity. In fact, in every instance the alloy was
unsound and weaker than the brass itself.
Iron refuses to alloy with magnesium in any sensible
amount, and so far as our experiments indicate anything, the
magnesium would seem to have no value either as flux or as
a strengthening element. Magnesium and aluminium alloy
with increase of strength of the resulting composition up to
10 per cent, magnesium, when the alloy becomes brittle
and valueless for constructive purposes. The following are
figures obtained :
MAGNESIUM-ALUMINIUM ALLOYS.
NO. OF SAMPLE.
PER CENT.
MAGNESIUM.
LIMIT OF
ELASTICITY.
TENACITY.
MODULUS OF
ELASTICITY.
o
2
5
10
30
4,900
8,700
13,090
14,600
I3,6S5
15,440
17,850
19,680
5,ooo
I,69O,OOO
2,65O,OOO
2,917,000
2,650,000
je
16
The addition of magnesium to cast aluminium increases
its tenacity by a percentage which exceeds five times that
of the per cent, of admixture. The best of these alloys are duc-
tile, and can probably be increased in tenacity 50, possibly 100
per cent, by cold-working pure, well-fluxed, and sound sam-
ples, and the sustaining power thus carried up to lengths far
exceeding those of " mild " steel.
The only recorded figures for alloys of copper with small
doses of magnesium which have come to the knowledge of
564
APPENDIX.
the Author, previously to those obtained in Sibley College
work, are reported by M. Mouchel, but the composition is
not given. The tenacities of these bronzes are substantially
the same, it is said, as those found for silicium bronzes in
similar form, — that of fine wire. They range from 50 to
nearly 100 kilograms per sq. mm., of from about 70,000
to 140,000 pounds per square inch ; where made for elec-
trical transmissions — and with conductivities of from 95 to
50 per cent.; but they have been given 10 per cent, higher
tenacities when it has been found practicable or desirable to
employ alloys of conductivities as low as 20 per cent.* The
densities of these alloys are not stated ; but if Mouchel's
compositions change by single tenths of one per cent., the
effect of magnesium on copper is obviously very consider-
able, both in reduction of density and increase of tenacity.
The same authority elsewhere gives the conductivity of cop-
per containing one-tenth per cent, magnesium as 94.29^
The following is the table :
COPPER-MAGNESIUM ALLOYS.
TENACITY.
CONDUCTIVITY.
PROPORTION OF
COPPER = I.
MG.
LBS. ON SQ. INCH.
KGS. PER SQ. MM.
95.16
73,659
51.80
0.001
81.60
86,869
6l.O9
2
63.89
106,892
75-17
3
58.01
H5,7l8
81.37
4
51-43
135,767
95-49
5
50.61
108,740
76.47
6
21...
29,862
21.00
?
Comparing magnesium with other substances, on the basis
of combined strength and lightness, the length of a prism of
uniform cross-section which the metal can carry suspended
vertically is probably the best standard ; it was this which
was adopted in the paper above referred to in the endeavor
* " Reports on the Paris Exhibition of 1889," vol. iv, p. 233.
t Ibid., vol. iv, p. 232.
APPENDIX.
565
to ascertain the relative value of metals and other substances
for aeronautical construction. Taking the tenacities of mag-
nesium as from 22,000 to 32,000 pounds per square inch, it
would sustain from 30,000 to 40,000 lineal feet of its own
substance, or the equivalent of steel of 100,000 to 150,000
pounds tenacity. The latter is a tool steel and only ex-
ceeded by the wire-drawn and rolled steels of exceptional
fineness and thinness, which sometimes attain tenacities of
300,000 and even 400,000 pounds per square inch, and are
capable of sustaining from 20 to 25 miles of their own
material. Machinery now built of open-hearth or Bessemer
steel of common tenacities, if constructed of these materials
of exceptional lightness and strength, would be correspond-
ingly reduced in weight. Thus, the lighter marine engines
seldom fall below 200 pounds per horse power ; although
torpedo-boat machinery and the engines of fast steam
yachts sometimes fall to one-half, or even, in rare instances,
to one-fourth these figures. Were it practicable to con-
struct such machines of aluminium, their weights would
be but little reduced. Could they be made of magnesium,
the weights would be reduced about 50 per cent. But,
on the other hand, could the ultimate tenacity of abso-
lutely pure steel in the form of fine wire or watch-spring
be used, the weights would become from 50 to 15 pounds
per horse power. The maximum molecular tenacity of
the finer steels is probably not less than 400,000 pounds
per square inch, and when we shall be able to so purify
and compact our metals as to attain this maximum, steam
engines may be constructed of standard design, similar to
those to-day employed, and not exceeding 10 or 12 pounds
weight per horse power ; and exceptional designs, such, for
example, as those adopted by Maxim and by Langley — who
have actually introduced the finer steels in strongest forms,
and who have already thus brought down the weight of
engines alone to 10 and 6 pounds per horse power — would
probably give us weights as low as 3 or 5 pounds per horse
power. Magnesium has thus no promise of competition with
steel, in general construction ; but its place may nevertheless
566 APPENDIX.
be very probably found in bearings and cast parts, even
where the running parts are steel.
It curiously happens, also, that some of the woods may,
for such parts as they may be adapted to, compete not only
with magnesium and its possible alloys, but also with these
fine steels. Professor J. B. Johnson finds tenacities of 20,000
to 30,000 pounds for woods weighing one-twelfth as much as
steels, or where strengths and lightness combined are com-
pared, having values equivalent to steels at tenacities of a
quarter of a million pounds and upward.
It is thus evident that until we know more than at pres-
ent of the gain to be secured by alloying other metals with
magnesium, it can only be said that it seems a possible rival
of aluminium.
The fact that we find aluminium alloyed with small per-
centages of titanium and of other metals, gaining enor-
mously in strength, without serious loss of its peculiar light-
ness— sometimes doubling its value on the above scale of
comparison, and becoming the equivalent of steel of 150,000
pounds tenacity — renders it extremely possible that the same
or greater effect may be found to obtain with magnesium,
and that one of our most promising fields of investigation
is now among its alloys. Both aluminium and magnesium
alloys may have important applications in the construction
of electro-dynamic machinery. It is known that the con-
ductivity of the former alloyed with copper, titanium, and
silver, is very high.
Magnesium-aluminium alloys containing 10 per cent, mag-
nesium resemble zinc, with 15 per cent., brass, and with 20 per
cent., bronze. They give good castings and are resistant to
the atmosphere, are fairly hard and work as well as brass.
The alloys are lighter than aluminium, and while possessing
no great strength, are of value for many purposes where a
light metal like aluminium would be used, if it could be cast
and worked successfully.
Partinium is a new alloy of aluminium now being tried for
the bodies of motor-vehicles. The aluminium is alloyed with
APPENDIX. 567
tungsten, and the resultant metal is said to have a specific
gravity of 2.89 cast, and 3.09 rolled ; the elongation varies
from 6 to 8 per cent. ; its tensile strength is given as from
45,500 to 52,600 pounds per square inch. It is said to be
cheaper than aluminium, nearly as light, and to possess greater
strength. (See Wright's studies of ternary alloys of these
metals; Proc. Roy. Soc. of London, 1891-4.)
PRODUCTION OF ALUMINIUM.
BY R. H. THURSTON.
A remarkable and most simple and beautiful device, how-
ever, after a time revolutionized the manufacture of aluminium
and through the utilization of this unpromising compound in
electrolytic work. This was the discovery or invention, per-
haps both discovery and invention, of Mr. Charles M. Hall, at
the time a student or alumnus of Oberlin University.
This process consists in the solution of alumina in, as he ex-
presses it, " a bath composed of the fluoride of aluminium and
the fluoride of another metal more electro-positive than alu-
minium " — i. e., some metal, as sodium, having higher affinities
and less easy of reduction than the aluminium itself. It was
found that the oxide is freely soluble in cryolite, for example,
the natural double fluoride of sodium and aluminium, and still
more so when a slight excess of the sodium fluoride is added.
In a molten " bath " of this double salt, alumina dissolves "as
freely as sugar or salt in water." A molten mass of cryolite is
maintained fluid at its comparatively low melting point and by
a voltage which is not far from, in this case, 4.5 volts, and a cur-
rent of a dozen amperes. Adding ten to twenty per cent, its
weight of alumina, a substance which only fuses at a white
heat, the bath, at its low red heat, instantly dissolves it, in spite
of the cooling effect of adding so much material at the tem-
perature of the atmosphere, and it is seen that the pointer of
the volt-meter drops as if freely falling, while the ammeter as
promptly shows a rising amperage. The solution is evidently
effected instantly. Thus the alumina is dissolved — not melted
$68 APPENDIX.
or fused, in the ordinary sense — and, becoming a conductor
through this solution, which we may perhaps correctly call the
equivalent of a low-temperature fusion, it becomes also an elez-
trolyte and can now be decomposed by any current exceeding
2.8 volts intensity.
Allowing the decomposition thus to proceed, the dose of
alumina is, after a time, exhausted and the voltage rises, as
sharply, very nearly, as it originally fell on introduction of the
salt, and the amperage coincidently falls off, showing a won-
derful sensitiveness in the bath. By continuously supplying
alumina, the process becomes a continuous one of indefinite
period. No impurities being introduced with alumina or sol-
vent, the restoration to the bath of the equivalent alumina, as
aluminium is removed, maintains the conditions of its opera-
tion constant, and for as long a period as it may be desired to
work, or until the introduction of impurities with either the
solvent or the dissolved salt compels its purification.
Every requirement of successful electrolysis is here pro-
vided. The solvent fuses at a low temperature — perhaps about
900 or 1000° F. — dissolving the electrolyte freely, notwith-
standing its high temperature of fusion — between 3000° and
4000° F. — and offers such an adjustment of voltages of decom-
position of the respective intermingled salts as insures the
electrolysis of the alumina first. It is a freely conducting
bath, when the alumina is in solution, and a distinctly more
resisting fluid when the solution is broken up by the removal
of the alumina. Its density is such as to permit the reduced
metal to fall to the bottom of the bath, instead of, as would be
the fact with many other molten salts, floating it to the sur-
face where it would be oxidized, perhaps, as rapidly as formed.
The alumina employed in this operation is the native ore
" bauxite " which maybe found in many parts of the world
and in large quantities. It is readily freed from its impurities
and thus it serves its admirable purpose in this process. Cryo-
lite is less generally distributed and is comparatively costly ;
but as it is not broken up in this process and only small wastes
need be made up, the tax upon the business through the cost
of cryolite is small. The low voltage needed in electrolysis of
APPENDIX. 569
alumina, once it is dissolved and thus rendered electrolytic,
makes the cost of current and of power in this application of
energy comparatively small, also ; and the total cost of reduc-
tion of the metal on a commercial scale is so moderate that
the introduction of this method has thrown out of use all
others ; it now makes the aluminium of the world. Even the
cost of fusion of the bath and of maintaining it in a fluid state,
when the operation is conducted on the large scale of com-
mercial production, is extinguished. The heat incidental to
the traversing of the bath by the current, and the combustion
by the oxygen separated from the alumina, of the carbon
anodes of the cells, when the cells are two or three feet wide
and four or five feet long, and where there are twenty to forty
carbon anodes of 2\ inches diameter and several inches length
below the surface of the bath, is quite sufficient to maintain
the bath in fusion and to keep the system in steady operation.
By this invention and process, the costs of the metal have
been very rapidly reduced. Its price in the market, as one of
the rare metals, a few years ago, was several dollars an ounce ;
as late as 1885, it cost about $5 a pound and then only in alloy
with other metals ; in 1889 it had come down to $1.50 to $2.00,
and then, as this new method came into use and developed in
magnitude of production, the price rapidly fell, the world over,
until, in 1898, it sold in tons at 25 to 30 cents a pound and
thus became, volume for volume, a cheaper metal than copper,
tin, brass or bronze. The product as rapidly increased in
quantity, all finally being made by the alumina process, thus : —
PRODUCTION OF ALUMINIUM.
Price
per Ton.
$5,500
2,500
1,500
1,400
900
1895 1, 800 800
I8g6 2,000 750
1897 2,500 700
1898 4,000 600
1900 7,500 600
Date.
1800. .
Product :
Tons per Yean
i8cn. .
1804..
57° APPENDIX.
The increasing magnitude of the apparatus of electrolysis
has had an important influence upon cost, by reducing wastes
of heat and current, and the magnitude of the scale of manu-
facture, at the same time, gives economy of production, thus : —
A 5O-h.p. plant is producing I pound per horse-power, per 24
hours' work. A loooh.p. plant produces 1.4 pounds per h.p.,
and a 3000- to 6ooo-h.p. plant produces 1.5, or more. The
reduction of conduction and other wastes of current, at such
low voltages as are required in this process, tell very powerfully
upon economy of operation. Thus, a gain of a single volt now
unnecessarily lost, where a total of six volts is employed at
each pot, means a gain of 16 per cent, in cost of power, which
is the principal item of cost. In many cases these losses are
enormous.
Purity of product is a peculiarity of these electrolytic pro-
cesses. Thus the market pays considerably more for electro-
lytic copper than for any other, with the single exception of
the native copper of the Lake Superior mines, which is very
possibly itself a product of nature's electrolysis. This purity
comes of the fact that no two metals have the same affinities
for their electro-negative associated elements. For this reason
the current may, in any given case, be adjusted, as to voltage
at the terminals of the electrodes, so as to give an intensity
intermediate between that voltage required for the separation
of the desired metal and that needed for the reduction of the
companion elements whenever it is practicable to find an
electrolyte in which the desired element stands at the foot of
the list in equivalent reduction-voltage. Thus : with a cryolite
bath and alumina in solution ; the latter is the lowest in re-
quired voltage for electrolytic decomposition, and it is only
necessary to so adjust the current as to give more than 2. 8 and
less than 4 volts within the bath to insure the deposition of
aluminium ; and, if the bath be itself pure or preliminary pur-
ified from undesired elements, absolutely nothing else can be
precipitated by the current. The product should thus be a
chemically pure metal, in this case. In fact it is possible, by
careful purification of the materials of the bath, to secure a
metal 99 per cent, fine, and better. The commercial article is
APPENDIX. 571
usually less pure as the raw material is not pure ; but it is pre-
ferred with some alloy, as being, for most uses, better ; the
alloy conferring upon it increased strength and hardness.
The production of aluminium by the electrolytic way is one
of the most interesting of all recent innovations in the art of
metallurgy, the process being one illustrating a most singularly
remarkable method and the product being practically a new
material of construction. The industry thus created has rapidly
come to be an important division of modern metallurgical
production. The arts are by its introduction promoted in
many new and unanticipated ways ; a new industry is given
the world to add to that diversification which is one of the
vital elements of advancing civilization and the discovery of a
new application of the electric energies opens the way into a
new field of promise for further exploitation by the chemist,
the electrician, the metallurgist, the engineer and the con-
structor, in many departments of the modern industrial
arts.*
§ ^5, p. 305. — Aluminium is displacing copper as a conductor,
the product of weight into conductivity and price having fallen
sufficiently to give some advantage in its use. Added to steel
also, as now practised extensively, the following advantages
are said to result : —
(1) The increase of sound ingots and consequent decrease
of scrap and other loss.
(2) It increases the fluidity of steel and allows successful
pouring of cold heats.
(3) Increases homogeneity
a. by preventing oxidation ;
b. by alloying rapidly with steel, and thereby increasing the
ease with which other metals alloyed with it will alloy homo-
geneously with steel ;
c. by allowing the steel to remain molten longer and, when
solidifying, doing so more evenly.
(4) It increases tensile strength without decreasing ductility.
'" SIBLEY JOURNAL OF ENGINEERING : Proceedings of the Electrical Society
of Cornell University, June, 1899.
572
APPENDIX.
(5) It takes out oxygen or oxides ; aluminium acting in the
same way as manganese. Good steel has been made for elec-
trical purposes, using aluminium in place of manganese.
(6) It renders steel less liable to oxidation.
(7) It furnishes smooth castings.
Aluminium is usually added in proportions of from one-
fourth to three-fourths of a pound to the ton of steel ; being
added either in the ladle or as the metal is being poured.
Aluminium combines with iron in all proportions.
None of the alloys, however, have yet proved of value, ex-
cept those of small percentages of aluminium with steel, cast
iron and wrought iron. So far as experiments have yet gone,
other elements can better be employed to harden aluminium
than iron, and its presence in aluminium is regarded as entirely
a deleterious impurity, to be avoided if possible.
TENSILE STRENGTH OF ALUMINIUM BRASS ALLOYS.
Aluminium.
Copper.
Zinc.
Tensile Strength per
Square Inch.
.00
57.00
42.CO
Pounds.
68.600
•15
55-80
43-00
70. 200
.25
70.00
28.00
36.900
•50
78.00
27.50
42.300
•50
77.50
21.00
33.417
2.00
70.00
28.00
52 800
2.00
7O.OO
28.00
52.000
2. *0
68.00
30.00
6r.400
3-00
67.00
30.00
68.600
3.30
63.00
33-30
86. 700
3-30
63.30
33.30
77.400
3-30
63.30
33.30
92.500
3-30
63.30
33.30
90 oco
5 80
67.40
26.80
96.900
Aluminium heated in presence of many oxides reduces the
metal from the oxide, and so energetically that Goldschmidt
has employed this method in obtaining chromium, magnesium,
and other rare metals. The oxide of the metal required is
packed, in excess, with finely divided aluminium and, some-
times, with sand, and the mass ignited. The combustion which
results develops intense heat, and complete reduction of the
APPENDIX. 573
oxide follows, with as complete oxidation of the aluminium,
and a pure product can be thus obtained.*
" The burning of aluminium as fuel gives us sapphires and
rubies in the place of ashes, and metallic fuel is burnt, not by
the air above but by the oxygen derived from the earth
beneath, as it occurs in the red and yellow oxides to which our
rocks and cliffs owe their color and their beauty." f
HEAT EVOLVED BY BURNING ONE GRAMME. f
»—«•
Aluminium .............. _____ AlaO3 7*250
Magnesium .................. MgO 6,000
Nickel ...................... NiO 2,200
Manganese .................. MnO9 2,110
Iron ........................ FeaO3 1,790
" ..... ................... FeO 1,190
Cobalt ....................... CoO 1,090
Copper ..................... . CuO 600
Lead ........................ PbO 240
Barium ..................... BaO 90
Chromium ................... CraOs 60
Silver ........ ............... Ag2O 30
Carbon COa 8,080
" CO 2,417
Silicon SiOa 7*830
§ 269, p 477. — At a recent meeting of the Royal Society of
New South Wales a paper by Professor Warren and Mr. S. H.
Barraclough (M.E., Cornell University, 1895), was read on the
effect of temperature on the tensile and compressive properties
of copper. The investigation was carried out on some fifty
copper test pieces. The temperature range attained was from
25° Fahr. to 535° Fahr., the temperatures being measured by
certified mercurial thermometers. The chief conclusions
arrived at were : (a) The relation between the ultimate tensile
* Zeits. fur Electrochemie, 1898, iv., 21, p. 494; Sci. Am. Supp., May 20,
1899, p. 19553.
f Royal Institution Proceedings, vol. xvi., part iii. — Roberts-Austin.
574 APPENDIX.
strength and the temperature may be very closely represented
by the equation f — 32,000 — 2i/, where / is the tensile
strength expressed in pounds per square inch, and / is the tem-
perature expressed in degrees Fahr. (U) Temperature does not
affect the elongation or contraction of area in any regular
manner ; and at any one temperature the variation in these
two quantities is so variable for different specimens that no
particular percentage could be included in a specification for
the supply of copper, (c) The elastic limit in tension occurs
at about 5,400 Ibs. per square inch ; this limit probably de-
creases rapidly with increase of temperature, but the differences
in the behavior of individual specimens are so great as to pre-
vent the determination of the relationship between the two
quantities, (d) The elastic limit in compression occurs at
about 3,200 Ibs. per square inch ; it decreases with increase of
temperature, the relationship between the two being more
regular than in the tensile tests, (e) The rate of permanent
extension and compression increases rapidly with increase of '
temperature.
INDEX.
ART. PAGE
Alloys 28 39
aluminium 99, 100 178, 180
[See Antimony.]
Babbitt's anti-friction 139 215
[See Bismuth, Brass.]
Britannia metal 126 2O2
cadmium and copper 107 186
characteristics 60 IO2
chemical natures 6l 104
classified lists 142, 143 226
composition, special standard 141 218-222
conductivity, electric 68 120
thermal 67 118
[See Copper.]
crystallization 69 123
effect of small doses of metal 135 212
electric conductivities. 68 120
expansions by heat 60 116
ferrous copper , 196 319
fusible 117 193
fusibility 63 no
German silver 102,138 182,215
gravities, specific 62 108
grey ternary 265 450
heat conductivities 67 118
expansions 66 116
specific 65 116
investigations, early. 266 451
indium and platinum 128 203
iron, copper and tin 96 174
zinc 95 174
and tin 113 189
iron and manganese 127 203
[See Kalchoids, Chap. VI., Lead.]
liquation 64 113
lists, classified 143 226
manganese bronze 97, 98, 194, 195 175, 176, 316, 317
andiron 127 203
maximum 258-263 440-447
mechanical properties. 71 126
nickel and copper 101 181
and zinc 102 182
oxidation 70 1 24
pewter 120 202
platinum and iridium 128 203
I
II
INDEX.
ART. PAG8
Alloys, preparation 134 210
phosphor bronze 192, 193 312-314
properties [See Chap. III.].
recipes, special 142 221
[See Resistances.]
Spence's metal 129 204
specific gravities 62 108
heats 65 116
silicon and copper 109, no 187, 188
solders 140 276
special recipes 142 222
ctandard compositions 141 218
sterro-metals 220 368
[See Strength, Tin.]
thermal conductivity 67 1 18
uses 93 172
[See Zinc.]
Thurston's maximum 258-262- 440-447
Aluminium 51, 185 88, 305
bronze 99 178
uses loo 180
Analyses 27 39
and mixtures of copper-zinc alloys 227 376
Ancient knowledge of metals I 3
Anderson's experiments with gun-bronze „ 188 308
Annealing 293 526
and tempering, effect on density 276 484
tenacity 277 487
Anti-friction metal, Babbitt's 139 215
Antimony . . . : 47 83
bismuth and lead 122 202
tin 112 188
and zinc „ 125 202
and copper 104 185
and lead 118 196
and tin 123 202
tin and zinc 124 202
Appearance of brass, test-pieces 224 371
fractures 225 373
bronze test-pi«ces, external 201 325
Appendix — •„ 559
Arsenic in alloys 55 95
Art castings in bronze 13° 2I2
Babbitt's anti-friction metal 139 2I5
Bar copper 3° 59
Behavior of bronzes under test 202 326
[See Mechanical Treatment, Resistances.]
Bell-metal 189 308
Bischoff's tests 185 3°3
Bismuth alloys 116 190
antimony, tin, and lead 125 202
bronze 106 187
and copper 105 186
fusible alloys 117 *93
lead and tin 117 193
ores 48 83
Brass [See Chap. V., X.].
INDEX. II :
ART. PAGE
Brass, alloys tested 223 370
analysis of mixtures 227 376
appearances of fractures 225 373
appearances of test pieces 224 371
application in arts 87, 90 159, 167
[See Bronzes.]
casting, temperatures < 226 375
classification, Mallett's 86 159
comparison of ductilities 244 412
elastic limits 241 409
moduli 242 411
resiliences 240 409
resistances 239 406
specific gravities 243 412
compressive resistance 232 385
conclusions , 245 413
from tests 239, 245 379, 413
compositions 85, 227 158, 376
definitions 84, 210 158, 366
ductilities [See Resistances, below] 244 412
elastic limits 241 409
moduli 221 368
experiments, early 219 367
fractures, appearances. . , 225 373
foundry 131 207
[See Kalchoids, Chap. VI.]
Mallett's classification 86 159
mixtures and analyses 85, 227 158, 376
moduli compared 242 41 1
of elasticity 221 368
Muntz metal 88 160
notes on tests 230 383
properties 92 165
special 89 161
records of tests 236 393
resiliences compared 240 409
resistances compared . 239 406
compressive 232 385
results of tests 228 378
shafts 235 392
tensile 231, 237 384, 404
torsional 234 391
transverse 233, 238 387, 406
results of tests « 228 378
shaft resistance 235 392
special properties 89 161
specific gravities compared 243 412
Britannia metal. 126 202
Bronze [See Chaps. IV., VI., IX.].
abrasive resistance of phosphor-bronze * 193 314
all°ys 72, 74, 197 130, 134,320
tested 199 322
aluminium 99 178
uses 100 180
Anderson's experiments on gun-bronze 188 308
appearance, external, of test pieces 201 325
fractures 203 330
behavior under test 202 326
IV INDEX.
ART. PAGE
Bronze, bell-metal, Mallett's experiments 189 308
bismuth 106 187
[See Brass.]
Casting, temperature 200 324
comparison of conductivities 216 363
ductilities 225 361
elastic limits 213 358
hardness 217 363
moduli of elasticity 214 361
resistances 210 350
resiliences 211 355
specific gravities 212 355
compression [See Condensation, below] 208 340
resistance of ordnance-bronze 190 309
conductivities, comparative 216 "63
condensation [See Compression, above],
Dean process 297 530
Uchatius' method 298 531
experiments 299 538
deductions 300 540
[See Copper.]
Dean's process of condensation 297 530
denned 72, 186 30, 306
density 79 141
ductilities, comparative 215 361
early compositions 77 139
elastic limits, comparative 213 358
elasticity moduli, compared 214 361
ferrous copper, strength 196 319
fractures, appearances 203 330
gravity, specific 212 355
gun [See Ordnance].
hardness, comparative. ... 217 363
Riche's experiments 191 312
heat, modifying tenacity 270 477
history 73 131
impact resistance of manganese-bronze 195 317
[See Kalchoids, Chap. VI.]
manganese-bronze 97 175
impact resistance 195 317
preparation 98 176
strength 194 316
maximum, Thurston's 258 440
metals used in research 198 322
moduli of elasticities, compared 214 361
oriental 78 140
ordnance ... 80, 187 141, 306
Anderson's experiments 188 308
[See Compression and Condensation, above.]
Wade's experiments 190 309
phosphor-bronze 81 143
abrasive resistance 193 314
tenacity 192 312
uses 82 145
preparation of manganese-bronze 98 176
properties 75 136
principal .... 76 137
records of tests 204 335
INDEX.
ART. PAGE
Bronze, results final 205 341
resistances, abrasive, phosphor-bronze 193 314
behavior under test 202 326
compared 210, 218 346, 350
l * c ,, condensed gun-bronze 190 309
Uchatius' experiments 299 538
deductions. 300 540
conductivities 216 363
ductile 225 361
elastic limits 213 358
moduli 214 361
ferrous copper 196 319
hardness 217 363
Riche's experiments 191 311
manganese-bronze 194 317
impact 195 317
phosphor-bronze, abrasive 193 314
tenacities 192 312
tensile strain-diagrams 206 374
transverse strain-diagrams 209 348
silicon-bronze no 188
specific gravities 212 355
strength [See Resistance].
stress prolonged, effect 281 497
table , 83 149
temperature of castings 200 324
tenacity modified by heat 270 477
tension, strain diagrams 206 344
test records 204 . 335
test pieces, appearance 201 325
behavior under test ;...-.. 202 326
Thurston's "maximum " 258-262 440-447
[See Tin.]
transverse strain-diagrams 209 348
Uchatius' experiments in compressed bronze 299 538
deductions. 300 540
methods. .278 531
uses of aluminium-bronze 100 180
phosphor-bronze 182 145
Wade's experiments on gun-bronzes 197 320
Bronzing 144 237
Calcination and roasting 3 9
Casting in bronze 136 212
chill, effect 275 483
temperatures 200, 278 324, 488
Characteristics of metals 22 30
[See Properties, Resistances.]
Chill-casting 275 483
Chemical analyses 227 376
character of metals 27 39
nature of alloys 61 104
processes in metallurgy, schedule 2 5
Classification of brasses, Mallett's 86 159
useful alloys 143 226
Cold-rolling, Lauth's process 296 529
tension, " Frigo '"-tension 301 540
VI INDEX.
r* , , , . ART-
Cold-working metals 294 527
bronze 310 556
Dean's process 297 530
Uchatius' experiments 298 53 1
deductions 300 540
V"011"-; « 309 555
Lavroff s process 290 523
Commercial copper 35
lead 46 81
metals, prices 59 gg
rare 58 98
tin 39 66
Comparison of conductivity 216 363
ductility 215 361
elastic limits 213 358
hardness 217 363
methods 302 540
moduli of elasticity 214 361
resiliences 211 353
resistances 2io 350
specific gravities 212 355
Complex copper alloys 115 189
Compression, brass 232 385
bronze 190 309
strain-diagrams 208 346
copper 171 278
Dean's process 297 530
hardness 16, 217 20, 363
Lavroff's process 290 523
[See Ductility.]
malleability 20 27
non ferrous alloys 157 255
[See Tenacity.]
Uchatius' methods, experiments, deductions. 298-300 531-540
Conclusions, brasses and other copper-zinc alloys 229, 245 378, 417
kalchoids and copper-tin-zinc alloys 261 446
mechanical treatment 311 557
Condensation [See Compression, above\.
Conductivity 17 21
electric 17 21
of alloys 68 120
bronzes 216 363
thermal 17 21
of alloys 67 118
bronzes 216 363
latent heat 26 36
Copper and antimony 104 185
and bismuth 105, 106 186, 187
bar 36 59
and cadmium 107 186
commercial 35 55
tests 169 272
complex alloys 115 189
compression 171 278
by impact 172 281
distribution 29 42
Dronier s alloy of 114 189
elasticity, modulus 174 286
INDEX. VII
ART. PAGE
Copper and German silver 102,138 182,215
heat, modifying tenacity 269 476
history 29 42
impact, compression by 172 281
and iron 103 183
and tin and zinc 113 189
and iron and zinc 95 174
[See Kalchoids, Chap. VI.]
lead 108 187
and tin HI 188
mercury 114 189
modulus of elasticity 174 286
and nickel 101 181
and zinc 102 182
properties 34 54
qualities 30, 168, 174, 176 43, 271, 286, 287
resistance 167 270
compressive 171 278
to impact 172 281
elastic modulus 174 286
shearing 170 277
tensile 167 276
torsional 175 287
transverse 173 284
shearing, resistance 1 70 277
sheet 36 59
and silicon 109,110 187,188
sterro-metal 247 415
tenacity 167 270
modified by heat 269 476
tests [See Resistance, above] 168 271
commercial copper 169 272
mean results 176 .287
torsional 175 287
transverse 173 284
and tin [See Bronze].
and zinc 94, 248 172, 416
torsional resistances 175 287
transverse tests 173 284
and zinc [See Brass].
Crystallization 23, 69 30, 125
Dean process applied to bronze 297 530
Deflection, effect of stress „ 284 502
[See Resistance, Transverse.]
Density, annealing effects 276 484
bronze 79 141
[See Mechanical Treatment.]
Discussion of experiments on kalchoids 260 443
Distribution of resistances 160 258
Dronier's alloy 1 14 189
Ductilities 20 27
[See Annealing.]
brasses, compared 244 412
bronzes, compared 21 e; 361
hardness 16,191,217 20,311,363
kalchoids and other copper-tin-zinc alloys 256 434
and malleability of metals 20 27
VIII INDEX.
ART. PAGB
Ductilities [See Elastic Limit, Elasticity, Mechanical Treat-
ment, Resistances, Strain-diagrams].
Earlier experiments 219 367
investigations 266 451
Early bronzes 77 139
Elastic limits of brass and other copper-zinc alloys 241 409
bronze and other copper- tin alloys 213 348
effect of stress, intermitted 285 508
variable 286 512
exaltation . .' 306 550
non-terrous metals 152 249
Elasticity [See Annealing, Ductility, Mechanical Treatment].
modified by heat 272 480
moduli for brass and other copper-zinc alloys 221 368
bronze and other copper-tin alloys 214 361
copper 174 286
tin 179 294
[See Resilience, Resistance, Shock.]
non-ferrous metals 153 251
proportioning for 155 255
[See Strain-diagrams.]
Wertheim's work 184 300
Electric conductivity 17 21
of alloys 68 120
bronzes 216 363
Engineer, requirements 12 17
Equations of resistance curves 151 248
Exaltation of elastic limit 306 550
Expansion by heat 24, 66 34, 116
Experiments [See Investigations].
Factors of safety 148 244
Ferrous copper, strength 196 319
Fluctuation of resistance 282 498
Fluxes 5 12
Forging, drop 291 524
hydraulic 292 525
Formulas for transverse loading 162 260
Frigo-tension 3OJ 54°
Fuels 6 13
Furnace manipulation 133 2O9
Fusibility 25, 63 3°» no
Fusible alloys H7> 120 193, 198
German silver 102, 138 182, 215
Grey ternary alloys 265 450
Gun-bronze [See Bronze].
Hammering and rolling 303 543
Hardness 16 20
of bronzes and other copper-tin alloys 191, 217 311, 363
[See Mechanical Treatment.]
Heat, annealing and tempering, effect on density 276 484
tenacity 277 487
conductivity 17 2I
ofalloys 67 118
bronzes 216 363
INDEX. IX
ART. PAGE
Heat, effect of sudden variations 274 482
expansion 25 34
of alloys 66 1 16
fusibility 26 36
of alloys 63 no
latent 26 36
modifications of elasticity 272 480
stress 273 481
tenacity of bronze 270 477
copper 269 476
various metals 271 480
specific 24 31
of alloys 65 116
temperature of casting of brasses 226 375
bronzes 220 324
effect on strength 278 488
thermo-tension 293 526
Historical discoveries 304 546
processes 308 550
History of the bronzes 73 131
copper , 29 42
experiments 305 548
discovery of the exaltation of elastic limits 308 552
strain-diagrams 307 551
Hydraulic forging 292 525
Impact, non-ferrous metals 153 251
proportioning for 155 255
[See Resilience.]
Improvements in ternary alloys 257 437
Investigations [See Metals and Alloys in detail].
Anderson's experiments with gun-bronze 188 301
Bischoff 's method of test 185 303
early, in the zinc-tin alloys 266 451
Mallett's experiments with bell-metal 189 308
[See Mechanical Treatment.]
Riche on hardness of bronze 191 311
Thurston's investigations, transverse resistance. 160 258
torsional 166 269
impact on copper ... 172 281
tenacity of " ... 173 285
gun-bronze 190 309
copper-tin-alloys . . . 197 320
zinc " 222 369
plan of investigations. 249 417
model of ternaryalloys 252 427
maximum bronzes. . . 258 440
principle (effects of
time) 279 489
experiments on ditto
284-285 502-508
U. S. Test Board, copper-tin alloys 197 320
copper-zinc alloys 222 369
copper-tin-zinc alloys 248 416
Wade's experiments with gun-bronze 187 306
Wertheim on elasticity of alloys 184 300
Indium 56 '96
and platinum 128 203
X INDEX.
ART. PAGE
Iron and copper 103, 196 183, 319
and tin 96 174
and zinc 113 189
and zinc 95 174
and manganese 127 203
[See Mechanical Treatment.]
Kalchoids and other copper-tin-zinc alloys [See Chap. XI.].
Lacquering 145 239
Latent heat 26 36
Lauth's process of cold rolling 296 529
Lavroff process of condensation 290 523
Lead 43 77
and antimony 1 18 196
and bismuth 122 202
tin 123 202
and bismuth 125 202
bismuth and tin 117 193
commercial 46 81
and copper 118 187
and tin in 188
fusible alloys 117, 120 193, 198
galena smelting 45 79
ores 44 78
and tin I2O 198
Liquation 64 113
Lustre of metals and alloys 18 24
Magnesium 54 94
Malleability and ductility 20 27
Mallett's classification of bronzes 86 159
experiments with bell-metal 189 308
Manganese 57 97
bronze 97 *75
impact resistance 195 317
preparation 97 i?6
and iron 127 203
" Maximum " bronzes, Thurston's 258 440
Mechanical processes 7 T3
properties of alloys 71 126
[See Metallurgy.]
working of brass 91 I^3
metals 8 14
Mechanical treatment of metals and alloys [See Chap. XIV.].
cold-rolling, Lauth's process 296 529
cold-working 294 527
bronze 310 556
iron 309 555
comparison of methods 302 541
conclusions 311 557
condensation, Dean's process 297 530
Uchatius' method, ex-
periments, deduc-
tions 298-300 531-540
Dean process of condensation 297 530
discoveries 304 546
drop-forging. 292 525
INDEX. XI
ART. PAGE
Mechanical treatment ; exaltation of elastic limit 308 552
forging 291 524
drop 292 525
hydraulic 292 525
frigo-tension 301 540
hammering 303 543
historical 304 546
history of experiments 305 548
hydraulic forging 292 525
impact 172 281
Lauth's process of cold-rolling 296 529
Lavroff's process of condensation .... 200 523
qualities effected by 288 517
rolling 291,303 524,543
strain-diagrams 307 551
thermo-tension 293 526
Uchatius' method of condensation, ex-
periments, deductions 298-300 53*~54O
working of metals 8 14
brass 91 163
wire-drawing 295 527
Melting and casting 132 207
Mercury , 52 90
and copper, Dronier's metal 114 189
Metallurgy, calcination 3 9
chemical processes, schedule 2 5
copper ore reduction 32 47
fluxes 5 12
fuels 6 13
galena smelting 45 79
[See Ores.]
roasting 3 9
reduction of copper ore 32 47
tin ore 38 64
schedule of chemical processes 2 5
smelting 4 u
galena 45 79
zinc ores 41 41
tin ore reduction 38 64
zinc smelting 41 41
Metals [See Index in detail}.
ancient knowledge I 3
defined 9 16
useful 10 ii
various 183 298
Moduli of brass and other copper-zinc alloys, compared 242 411
elasticity of brass and other copper-zinc alloys 221 368
bronze and other copper-tin alloys 214 361
Modulus of elasticity 174 286
of tin 179 294
rupture . 163 262
Muntz metal 88 l6p
Nickel and its ores 49 84
copper ioi 181
and zinc 102 ig2
German silver 102, 138 182, 215
ores 49 84
37
XII INDEX.
ART. PAGE
Nickel and its uses 50 86
Odor and taste 21 28
Ordnance bronze [See Bronze].
Ores, aluminium 51 88
antimony 47 82
arsenic 55 0,5
bismuth 48 83
calcination 3 g
copper, distribution 29 42
sources 31 44
reduction 32 47
distribution, laws of II 17
fluxes 5 12
iridium 56 96
lead. , 44 78
smelting galena 45 79
magnesium 54 94
manganese 57 97
mercury 52 go
[See Metallurgy.]
nickel 49 84
platinum 53 92
reduction 3,4 9,11
roasting 3 9
smelting 4 n
tin, sources and distribution 37 64
reduction 38 64
zinc, sources 40 40
smelting 41 41
Oriental bronze 78 140
Oxidation 70 124
Pewter 126 202
Phosphor-bronze 81 143
abrasive resistance 193 314
tenacity ., 192 312
Platinum 53 92
and iridium 128 203
Preparation of alloys 134 2io
Prices of commercial metals 59 99
Proportioning for shock 155 255
Rare metals 58 98
Reduction of ores \See Ores] 3,4 9, 1 1
Resilience 154 252
of brass and other copper-zinc alloys, compared. . . . 240 409
bronze and other copper-tin alloys, compared 211 353
[See Elasticity, Elastic Limits.]
proportioning for shock 155 255
Resistance, conditions effecting [See Table of Contents, Chap.
XIII.].
brass and other copper-zinc alloys [See Table of
Contents, Chap. X.].
bronze and other copper- tin alloys [See Table of
Contents, Chap. IX.].
Copper-tin-zinc alloys [See Table of Contents,
Chap. XI .].
INDEX.
XIII
ART. PAGB
Resistance, Kalchoids and other copper-tin-zinc alloys [See
Table of Contents, Chap. XL],
mechanical treatment [See Table of Contents,
Chap. XIV.].
non-ferrous metals [See Table of Contents, Chap.
VIII.].
tin-zinc and other alloys [See Table of Contents,
Chap. XII.].
annealing, effect 276, 277, 293 484-487, 526
compressive, brass 232 385
bronze 190, 208 309, 346
chill-casting 275 483
copper 170 278
[See Mechanical Treatment, below^\
non-ferrous metals 157 255
conductivity, electric, of alloys 68 120
bronze 216 363
thermal 17 21
alloys 67 118
bronzes. , 216 363
[See Heat, below.'}
ductility, brasses, compared 244 412
bronzes, compared 215 362
kalchoids and other copper-tin-zinc al-
loys ... 256 434
elasticity, modification by heat 272 480
moduli for brass and other copper-zinc
alloys 221 368
moduli for bronze and other copper-tin
alloys 214 361
moduli for copper 174 286
tin 179 294
Wertheim 184 300
elastic limits, brass and other copper-zinc alloys 241 409
bronze and other copper-tin alloys. 213 358
exaltation 306 550
non-ferrous metals 152 249
[See Stress, below.']
fluctuation of resistance of bronze 282 489
fusibility 25, 63 36, no
hardness of bronze and other copper-tin alloys. 191, 217 311 , 363
heat, conductivity [See above. ~\
latent 26 36
modifications of elasticity 272 480
stress 273 481
temperature of casting 278 488
tenacity 269-271 476-480
mechanical treatment [See Table of Contents,
Chap. XIV.].
cold-rolling, Lauth's pro-
cess 296 529
cold- working 294 527
bronze 310 550
iron 309 555
Dean's process, condensa-
tion 297 530
forging, drop, hydraulic
291, 292 524, 525
XIV INDEX.
ART. PAGB
Resistance, mechanical treatment, f rigo-tension 301 540
hammering 303 543
Lauth's process, conden-
sation 290 523
rolling. 291, 303 524, 543
Uchatius process, con-
densation 298-300 531-540
wire-drawing...* 295 527
resilience 154 252
brass and other copper-zinc alloys 240 409
bronze and other copper-tin alloys. ... 211 353
[See Strain-diagrams, below.]
rupture, modulus 163 262
theory 161 259
safety-factors 148 244
shafts [See Torsional, below] 166, 235 268, 392
shearing, of copper 170 277
shock, non-ferrous metals 153 251
proportioning for 155 255
strain-diagrams, brass and other copper-zinc al-
loys, tension, transverse 237, 238 404 406
Strain-diagrams, bronze and other copper-tin
alloys, tension, compression, and transverse.
206, 208, 209 346, 347, 348
Strain-diagrams, kalchoids and other copper-tin-
zinc alloys 254 429
stress, intermitted effect on elastic limit 285 508
produced by change of temperature 273 481
repeated, effect on strength 287 515
steady and unintermitted 284 500
unintermitted, effect on deflection 283 502
elastic limit 285 508
variable effect on elastic limit 286 512
tempering, effect on density and tenacity. . . 276, 277 484-487
tensile [See Tenacity].
time [See Stress, above'].
time of loading, effect 279 489
torsional, of brass and other copper-zinc alloys. . 234 391
kalchoids and other copper-tin-zinc
alloys 246 414
non-ferrous metals, alloys 165 267
shafts 166, 235 268, 392
tin 180 294
zinc 182 298
transverse, brass and other copper-zinc alloys . . . 233 387
bronze and other copper-tin alloys.
197-205 320-341
copper 173 284
formulas 162 260
kalchoids and other copper-tin-zinc
alloys 246 414
non-ferrous metals 159 256
strain diagrams, brass and other cop-
per-zinc alloys 238 406
strain-diagrams, bronze and other
copper-tin alloys 209 348
time, effects. 279 489
tin 178 292
INDEX.
XV
ART. PACK
Resistance, transverse, zinc 182 298
wire-drawing 295 527
Rolling 291, 303 524, 543
Riche, hardness of bronze 191 31 *
Roasting 3 9
Rupture [See Resistance].
modulus 163 262
theory 161 259
Safety factors 148 244
Shafts, strength of 166, ^35 268, 392
Shearing, resistance of copper 170 277
Shock, non-ferrous metals 153 251
proportioning for 155 255
[See Resilience.]
Silicon and copper 109 187
Silicon bronze no 188
Smelting [See Metallurgy].
Solders 140 216
Specific gravities of alloys 62 108
brasses and other copper-zinc alloys. . . . 243 412
bronzes and other copper-tin alloys 212 355
densities and weights 19 25
Spence's metal 129 204
Standard alloys 141 218
Stereotyping 137 214
Sterro-metal 220, 247 368, 415
Strain-diagrams 150 247
of brass, tensile 237 404
transverse 238 406
bronze, compressive 208 346
tensile 206 344
transverse 209 348
kalchoids and other copper-tin-zinc alloys. 254 429
Strength [See Resistance].
Stress, intermitted, effect on elastic limit 285 508
produced by change of temperature 273 481
prolonged, effect 280, 281 492-497
repeated, effect on strength , 287 515
[See Resistance.]
steady and unintermitted 283 500
unintermitted, effect on deflection 284 502
elastic limit 285 508
variable, effect on elastic limit 286 512
Structure and composition of metals . . 158 256
Taste and odor 21 28
Temperature [See Heat].
Tempering [See Annealing] 293 526
effect on density 276 484
tenacity 277 487
Tenacity, annealing effects 277, 293 487, 523
bell-metal 189 308
brass 231 384
strain-diagrams 237 404
bronze 207 344
condensation 297-300 53°-54O
modification by heat 270 477
ordnance, Anderson's experiments 188
XVI INDEX.
ART. PAGB
Tenacity, bronze ordnance, Wade's experiments 187 306
strain-diagrams 206 344
cold-rolling, effects 296 592
working, effects 294 527
upon bronze 310 556
iron 309 555
copper 167 270
modifications by heat 269 476
\See Compression, Ductility.]
forging 291,292 624,525
fngo-tension 301 540
hammering 303 543
heat modifications, bronze * 270 477
copper 269 470
non-ferrous 268 476
various methods 271 480
kalchoids and other copper-tin-zinc alloys 255 430
non-ferrous metals, modifications by heat 268 476
fhosphor-bronze 192 312
See Resistance.]
rolling 303 543
cold [See Cold-rolling, above}.
Strain-diagrams, brasses 237 404
bronzes 206 344
tempering, effects 277 487
thermo-tension 293 526
various metals, modifications by heat 271 480
wire-drawing 295 527
Ternary alloys, grey 265 450
Tests [See Investigation].
Thermal conductivity 67 118
Thermo-tension 293 526
Thurston [See Alloys, Thurston].
Time [See Stress].
Time of loading, effect 279 489
Tin and antimony 119 198
bismuth and copper 112 188
lead 125 202
and lead 123 202
zinc 124 202
and bismuth and lead 117 193
commercial 39 66
and copper [See Bronze].
and iron 96 1 74
zinc 94, 248, 262 172, 416, 447
distribution 37 64
elasticity, moduli 179 294
fusible alloys 117 193
and lead 111,188 120,198
resistance 177 288
torsional 180 294
transverse 178 292
sources 37 64
stress prolonged, effect 280 492
ternary alloys, grey 265 450
and zinc 121, 263, 264 2OI, 449, 450
andiron 113 189
Torsional resistance of brass and other copper-zinc alloys . . . 234 391
INDEX. XVII
ART. PAGE
T&rsional resistance of bronzes and other copper-tin alloys. . 205 341
kalchoids and other copper-tin-zinc
alloys 251 259 419-442
non-ferrous metals 165 267
shafts 166, 235 268, 392
tin 180 294
zinc 182 298
Transverse loading, formulas 162 260
time effects 279 489
resistance, brass and other copper-zinc alloys. . . . 233 387
bronze and otner copper-tin alloys. . . . 186 306
copper 173 284
kalchoids and other copper-tin-zinc
alloys 246 414
tin 178 292
zinc 182 298
Strain-diagrams, brass and other copper -zinc
alloys 238 406
bronze and other copper-tin
alloys 209 348
5, non-ferrous metals 159 256
Vchatius* deductions 300 540
experiments on compressed bronze 299 533
method of condensation of metals 298 531
Wade's experiments on gun-bronze 187 306
Weights and densities 19 25
.'tfertheim on elasticity 184 300
Whitworth's process of compressing steel 289 519
Wire-drawing 295 527
£inc and antimony 124 202
copper [See Brass].
and iron 95 174
and tin 113 174
and tin 248 416
history 40 40
iron and tin 96, 1 13 174, 189
metallic 42 73
nickel 102 182
ores 41 41
smelting , 41 41
sources 41 41
strength 181 296
stress prolonged, effect 280 492
ternary alloys, grey 265 450
tests... 182 297
tin 151, 264 201, 449
density and strength 265 450
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Church's Mechanics of Engineering Svo, 6 00
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RAILWAY ENGINEERING.
Andrews's Handbook for Street Railway Engineers 3X5 inches, mor. 1 25
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Abridged Ed 8vo, 1 50
* Bartlett and Johnson's Engineering Descriptive Geometry 8vo, 1 50
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Durley's Kinematics of Machines 8vo, 4 00
Emch's Introduction to Projective Geometry and its Application 8vo, 2 50
Hill's Text-book on Shades and Shadows, and Perspective 8vo, 2 00
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11
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