CAST IRON HAVING FINE GRAPHITE IN FERRITIC MATRIX, AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To obtain a cast iron, in which matrix structure is formed into ferritic structure and fine graphite is contained and which is manufactured by sand mold casting without adding Ti at all and also without using chiller, and its manufacturing method. ;SOLUTION: The cast iron has a composition consisting of, by weight, 1.5-2.75% C, 2.5-5.5% Si, ≤0.5% Mn, and the balance essentially Fe and satisfying C %≥-Si %/2+4. A rare earth - Si alloy is added by 0.030 to 0.075wt.% before pouring. Moreover, this cast iron has fine graphite in a ferritic matrix. This cast iron having fine graphite in the ferritic matrix can be manufactured by adding, before pouring, 0.030 to 0.075 wt.% of rare earth - Si alloy to a molten metal having a composition forming fine graphite and then pouring the molten metal into a sand mold after the above addition of the rare earth - Si alloy.;COPYRIGHT: (C)2000,JPO