PROCESS FOR PREPARING AN ALUMINUM ALLOY SHEET WITH IMPROVED BENDABILITY AND ALUMINUM ALLOY SHEET PRODUCED THEREFROM

摘要

A process is described for producing an aluminum alloy sheet having excellen t bendability for use in forming panels for automobiles. An aluminum alloy is used comprising 0.5 - 0.75% by weight Mg, 0.7 - 0.85% by weight Si, 0.15 - 0.35% by weight Mn 0.1 - 0.3% by weight Fe, optionally 0.2 - 0.4% by weight Cu and the remainder Al and incidental impurities, and this alloy is cast into ingots by semi-continous casting. The ingot is subjecting to hot rolling and cold rolling, followed by solution heat treatment of the formed sheet. This sheet material is then pre-aged by rapidly cooling from an initial pre-aging temperature of at least 80~C t room temperature at a cooling rate of more th an 5~C/hour.