SPHEROIDAL GRAPHITE CAST IRON HAVING BAINITE MATRIX AND ITS MANUFACTURE

摘要

PURPOSE:To obtain spheroidal graphite cast iron having superior shock resistance by carrying out bainite forming heat treatment at a specified temp. so as to regulate the amount of retained austenite. CONSTITUTION:Austenitized cast iron is subjected to bainite forming heat treatment by isothermal holding in a salt bath at 300-400 deg.C and furnace cooling to obtain spheroidal graphite cast iron having a bainite matrix contg. 20-40% retained austenite. By the treatment, the impact characteristics are especially improved, so a new use for the spheroidal graphite cast iron can be found.