The effect of solidification conditions on phase transformation of iron matrix of Fe-25mass%Cr-C-B alloys

M2B, M-23 (C,B)(6) and M-7(C,B)(3) compound phases which constitute the eut ectic structures of Fe-25 mass % Cr-C-B alloys vary depending on both carbo n and boron content, The composition of the matrix structure also varies wi th each eutectic structure. Due to this, it is presumed that the transforma tion behavior of the matrix is affected by the solidification rate of the c ast material. In the present research, three kinds of molds are used in cha nging the solidification rate, namely, an exothermic mold, a sand mold and a metal mold. The alloys made from each mold are subjected to thermal expan sion tests in order to clarify the transformation behavior both in furnace cooling and air cooling conditions. The results indicate that the hardness of each alloy is higher in a mold where solidification is faster. Most of t he alloy transform to martensite during air cooling. Fn furnace cooling, lo w carbon with high boron alloys transform to bainite whereas, high carbon a lloys transform to pearlite. Furthermore, alloys with Power carbon content have ferritic matrix which does not transform to any other structure in any cooling condition.