Metallurgy Of Cast Iron

MIXTURES FOR HEAVY GRAY IRON CASTINGS. 275
.63. The average tensile strength is given as 31,350 pounds per square inch.
2. In making the chassis rails, base rings, hydraulic cylinders, and other parts of disappearing gun carriages at the Niles Tool Works, Hamilton, O., the following mixture (Table 52), melted in a cupola, was used:
TABLE 52.
No. 3 Muirkirk charcoal iron ......................................... 5 to 15 per cent
No. 4}£ Muirkirk charcoal iron ........................................... 3% to 15
No. 4 high L,andon charcoal iron ................................ 25 to 30 u
No. 4 low London, charcoal iron ............................................ 30 "
Gun iron scrap .......................................... 20 to 25 • "

Total... ................................. 100 per cent.

The analysis of this cupola iron gave silicon about i.oo, sulphur .05, manganese .6, phosphorus .3, graphitic carbon 1.40, combined carbon i. to 1.20. The tensile strength is given as about 33,000 pounds, on an average, and the elongation from .5 to .6 of i per cent. The above Landon iron is made by the Salisbury Carbonate Iron Co. (See page 278.)
3. A mixture made at the Columbus Machine Co.'s works, Columbus, O., which gave very satisfactory results with the iron melted in a cupola is as follows:
TABLE 53.
Muirkirk charcoal iron.................
Salisbury charcoal iron................
Kmbrevillc coke iron (high in C) .
Gun iron scrap............ ...................
Steel (hloom ends)........................
Total..
15 per cent.
25
20 "
30
10 "
ioo per cent.
The above gun mixture analyzed: Silicon 1.53, sul-ings, be mixed wholly with cast iron scrap, no pig whateverod wheel by Mr. A. Whitney is also given in Table 46.sly the same depth.... Shop scrap ...... 15 x ro x 1.50 i. So 22.50 iS.oo