Abstract: 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.degree. to 560.degree. C., at a heating rate of at least 2.degree. C. per second while it is heated from 150.degree. to 350.degree. C., and the sheet is then cooled to room temperature, at a cooling rate of at least 1.degree. C. per second while it is cooled from 420.degree. to 150.degree. C. The resulting heat treated sheet is subjected to final cold rolling with a reduction ratio of 15 to 60%.
Type:
Grant
Filed:
June 25, 1985
Date of Patent:
October 13, 1987
Assignee:
Mitsubishi Aluminium Kabushiki Kaisha
Inventors:
Yasuo Kobayashi, Michihiro Yoda, Hiromi Goto, Yo Takeuchi