Metallurgy Of Cast Iron

APPEARANCE OF THE FRACTURE OF PIG IRON. 165
old-school foundrymen. To illustrate how the latter may be duped by making them think their practice correct: A well-known firm, standing high in its ability to cast heavy machinery, recently sent an order to a furnaceman for one car of strictly all open-grade iron, to make strong castings for a special job. The author was consulted as to the analysis necessary, as the furnaceman knew he could select the open iron in almost any grade of silicon. Upon learning the character of the castingsa'equired from the furnaceman, the author recommended silicon between i.oo and 1.25, with sulphur about .030. A car of as beautiful open-grained coke iron as was ever seen was sent to the founder. Its results pleased him so much that in a few weeks the second order, " Send me another car of strictly open-grade iron, same as last,'' came in. The furnaceman, knowing the utility of chemical analysis, referred to his books and duplicated his last analysis, being careful, of course, to load nothing but an all open-grained iron, as, if he had sent a close-grained iron it would have been condemned. Now, this furnaceman is not going out of his way to advocate the utility of chemical analysis to that foundryman, and it would be almost useless for anyone else to attempt to do so, as the founder is stubborn in the belief that it is the open-grained iron of that peculiar brand which was wholly responsible for obtaining the results he desired. . Then again, should this founder, on account of a difference in price, change to another furnaceman who was not thoroughly posted in making mixtures for different castings, and who might not have had the forethought to consult some expert of the new school in regard to analysis, the chances are that his open-arding 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 "