PROCESS FOR PRODUCING ALUMINUM ALLOY CASTING

摘要

This process comprises steps (S1 to S4) for forming an aluminum alloy casting, a step (S6) for subjecting the casting which has been taken out of a mold to cooling with a cooling fluid, and a step (S10) for subjecting the cooled casting to artificial age-hardening, wherein the step (S6) is conducted in such a manner that: the temperature (a) of the casting at the initiation of the cooling is not lower than the solidification completion temperature minus 80ºC; the cooling rate (b) is 30ºC/min or more; and the temperature (c) of the casting at the completion of the cooling is not higher than the treatment temperature (d) of the subsequent artificial age-hardening. The process can dispense with a solution treatment step and thus attain reduction in equipment cost or energy consumption, and can yield, even by T5 heat treatment, a casting which exhibits a reduced residual strain and which can substitute for a casting which has been produced by T6 or T7 heat treatment.