ANALYSES AND STRENGTH OF TYPICAL IKONS.
The author has not seen any analysis of cupola iron shewing the combination of high combined carbon and silicon with the low sulphur shown in analyses Nos. i and 2. If any can closely duplicate such a combination of metalloids by cupola iron they should obtain about the same results in strength derived from the air furnace meltings. This may be closely approximated, but the uncertainty of cupola workings, on account of the iron being in contact with fuel and blast, makes it a difficult and a very unreliable method to adopt.
The state of the combined and graphitic carbon is the final resultant of the combined effects of all the other metalloids and chiefly defines what character the physical qualities will assume, as regards the strength, deflection, contraction, and chill of an iron, f
TABLE 60.—CHEMICAL ANALYSES OF SPECIALTY MIXTURES IN
CAST IRON.* Arranged according to degrees in strength.
No. of Analysis. Specialty Mixture. Sil. Sulp. Phos. Mang. Graph. Carbon Comb. Carbon Total Carbon
i Gun Metal. i.rg .055 .408 .420 2.050 1.130 3.180
2 Chill Roll. •?i •05« -543 •390 1.620 1.380 3.000
3 Car Wheel. .86 .127 .348 .490 2550 .920 3470
4 Heavy Machinery 1.05 .110 .543 •350 2.650 •330 2.980
5 Ligh t Machinery 1.83 .078 .504. .310 2 500 •43° 2.930
6 Stove Plate. 2-59 .072 .622 •370 2.950 •35° 3-3oo
7 Sash Weight. .18 .138 .094 •35" •ISO 2.940 3.090
*Nos. i and 2 are charcoal irons.
t The rate of cooling is also to he considered in connection with the effects of the metalloids.scrap of all kinds is best avoided where practical.stings as they are poured. Where there is any apprehension of such difficulty, it is often well to addo break, he can, by " siz-