Method of manufacturing aluminum alloy sheets excellent in hot formability

摘要

A method of manufacturing an aluminum alloy sheet excellent in hot formability. A hot rolled plate of an aluminum alloy is cold rolled into a cold rolled sheet with a reduction ratio of at least 20%. The cold rolled sheet thus obtained is subjected to intermediate heat treatment wherein it is heated to a temperature of 420 DEG to 560 DEG C., at a heating rate of at least 2 DEG C. per second while it is heated from 150 DEG to 350 DEG C., and the sheet is then cooled to room temperature, at a cooling rate of at least 1 DEG C. per second while it is cooled from 420 DEG to 150 DEG C. The resulting heat treated sheet is subjected to final cold rolling with a reduction ratio of 15 to 60%.