INSERT-CASTING METHOD OF STEEL MATERIAL BY AL ALLOY

PURPOSE:To improve the integrality of a composite material consisting of a steel material and an Al alloy and to improve low-temp. toughness by regulating the preheating temp. of a insert-casting material made of a steel and a metallic mold, the pouring temp. of the molten Al alloy and the temp. for starting quick cooling to prescribed temps. CONSTITUTION:An insert-casting material made of a steel is heated to >=350 deg.C. The molten Al alloy of the temp. expressed by the equation [where, T: pouring temp. ( deg.C), Ts; the temp. at which solidification starts ( deg.C), t; the temp. of a metallic mold and metallic fitting for insert casting ( deg.C), DELTAm; the total weight of the metallic mold and the insert-casting material in the part lower than the melt surface of the molten metal (g), M; the weight of the molten metal (g), Cm; the average specific heat of the metallic mold and the insert-casting material (Cal/ g deg.C), CAl; the specific heat of the Al alloy (Cal/g deg.C)] is poured into said metallic mold. The molten metal is quickly cooled after the molten metal attains the temp. at which the solid phase rate thereof does not exceed 40%, then the molten metal is successively cooled from the bottom side of the metallic mold.