Heat treatment method of high chromium cast steel for high temperature pressure vessel

摘要

PURPOSE:To obtain a high-Cr cast steel for a high-temp. pressure vessel having satisfactory ductility, toughness and superior strength at high temp. by restricting components in a high-Cr cast steel and subjecting the steel to normalizing, cooling, tempering, cooling and tempering. CONSTITUTION:The steel consisting of, by weight, 0.08-0.12% C, =0.7% Si, =0.8% Mn, 0.4-0.7% Ni, 9-11% Cr, 0.65-1.00% Mo, 0.13-0.20% V, 0.03-0.07% Nb, 0.03-0.07% N and the balance Fe with accompanying impurities is refined. The steel is normalized by heating to 1000-1100 deg.C, cooled to =250 deg.C, tempered once at 550-750 deg.C, cooled to =150 deg.C, and tempered again at 680-750 deg.C. By such a treatment, a high-Cr cast steel having characteristics necessary for a high-temp. pressure vessel is obtd.