摘要 |
PURPOSE:To obtain tough and hard cast iron by releasing alloyed graphite cast iron contg. prescribed percentages of C, Si, Mn, Mg, Ni and Mo from a mold at a temp. in the austenite range and by heat treating the cast iron under prescribed conditions. CONSTITUTION:Alloyed graphite cast iron consisting of, by weight, 3-4.5% C, 1.5-3% Si, 0.2-1% Mn, 0.02-0.1% Mg, 0.6-1.4% Ni, 0.2-0.8% Mo and the balance Fe is melted, cast in a mold, and released from the mold at a temp. in the austenite range of 850-950 deg.C. The released cast iron is hardened by controlled cooling from 850-950 deg.C to <=150 deg.C at >=75 deg.C/min average cooling rate, and it is tempered at 400-650 deg.C. |