METALLURGY OF CAST IRON.
Table 74. The analyses A2 and E>2 are also shown in Table 73, at D and E, page 335.
It was the belief, until the author's discoveries proved the contrary, that an iron once chilled would, upon being remelted, produce a much harder casting than if the same iron had never been chilled. This belief was so strongly maintained by founders, prior to the author's discovery, that in selecting scrap iron
GRAY ROLL. FIG. 63. CHILLED ROLL.
for mixtures with pig metal to make light or heavy machinery castings, etc., founders would reject the scrap that had been chilled, if it could be done, lest it might cause hard spots in a casting or make the whole too hard. Of course, it is to be understood that if a casting shows a chill, it is evidence that the gray body of the casting, if used for scrap, is not accepted as a soft iron, as if no part of the casting exhibited a chill; for, as a rule, founders know such fractures are not to be graded as soft iron. Nevertheless, they did not. 1.98 1.62 2. TO 1. 10 -53 .42 .92 i-55 T-73 1-55