Metallurgy Of Cast Iron

APPEARANCE OF THE FRACTURE OF PIG IRON. 171
from the pig and the castings seen in Fig. 37, while B gives that secured from Fig. 38.
TABLE 23.
Samples. Silicon. Sulphur.
A / pig 1.25 .035
A~~i Castings ...... ........ 1.15 .070

-R /Pig .................................................. 2.86 .040
(Castings ...... 2.67 .060

The fracture seen in Fig. 39 being enlarged will afford a better study of the difference existing between the grain of the pig, samples A and B. To the new-school founder Table 23 is sufficient to define the results, or whether samples A and B would give the soft or hard iron upon being re-melted; but for the old-school of founders Tables 24 and 25 will best serve such ends. A study of these latter tables will show them that the pig B which would have been condemned by those wishing to make soft castings, gave by far the least contraction and chill, so much so that the test pieces, only one-eighth inch thick, as seen at H, Fig. 38, are so soft as to be readily drilled, while at K, Fig. 37, made from sample A, a drill was broken in trying to get a hole through the thin piece one-eighth inch thick. In fact, we were foolish to try to touch it with a drill, as the metal was nearly all chilled or white in color. It is also to be said that all the other test pieces ranging from Nos. 2 to 12 that were made from the pig, sample A, were also much harder than those made from sample B. In measuring the depth of the chill, pieces were broken off one end of the test bars as seen at P, Fig. 37.ith chemical analysis, or the effect of one metalloid upon another, that they are in error, the writer melted down about one hundred pounds of each of the grades A and B in his twin-shaft cupola, seenng the advance of the new, see page 179.n is simply an average of the whole, generally taken from the two ends andith the uncertainty of furnace workings when in urgent need of ten hundred jon of iron; and Sir........................ 2,720 "