Patent ID: 7029543
Filing Date: 2006-04-18
Classification: C22C,C22F

Abstract:
1. A process of producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles, the process comprising the steps of: semi-continuously casting an aluminum alloy comprising 0.50 to 0.75% by weight Mg, 0.7 to 0.85% by weight Si, 0.1 to 0.3% by weight Fe, 0.15 to 0.35% by weight Mn, and the balance Al and incidental impurities, subjecting the cast alloy ingot to hot rolling and cold rolling to an intermediate gauge, batch annealing the intermediate gauge sheet, further cold rolling the annealed sheet to final gauge and heat treating the further cold rolled sheet, quenching the heat treated sheet to a temperature of about 60–1200° C. and coiling the sheet, and pre-aging the coil by slowly cooling the coil from an initial temperature of about 60–1200° C. to room temperature at a cooling rate of less than 10° C./hr., thereby obtaining a sheet having a bendability (r/t) value of less than 0.2.