HARD-BAKED-TYPE HIGH-STRENGTH CAN MATERIAL AND ITS PRODUCTION

PURPOSE:To manufacture a hard-baked-type high-strength can material excellent in formability by applying process annealing and finish cold rolling to an aluminum-alloy sheet having a composition in a specific range under respectively specified conditions. CONSTITUTION:A rolled aluminum-alloy sheet which has a composition containing, by weight, 0.5-0.8% Cu, 0.5-2.0% Mn, 1.3-2.5% Mg, 0.25-1.0% Zn, 0.3-0.7% Fe, and 0.2-0.7% Si and is prepared by means of soaking treatment, hot rolling, and cold rolling is first subjected to process annealing under the conditions of 450-600 deg.C heating temp., =about 100 deg.C/min heating rate, and >=100 deg.C/hr cooling rate. Subsequently, finish cold rolling is applied to the above sheet at 25-55% draft, by which a yield strength of 31-35kg/mm can be obtained by means of baking at 200 deg.C+ or -10 deg.C for 20min. By this method, the hard-backed-type can material having high strength and excellent in formability can be manufactured.