| CPC C22F 1/05 (2013.01) [C22C 21/08 (2013.01)] | 19 Claims |
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1. A method for improving aluminium alloy blank tensile yield stress and formability comprising successively:
rolling a 6xxx series aluminium alloy slab to form a sheet, wherein the rolling comprises hot rolling or a combination of hot and cold rolling;
performing solution heat treating and quenching of the sheet;
cold rolling the sheet with at least 20% cold work reduction;
cutting the sheet to form a blank, the blank comprising:
a flange configured to be held by a blank holder of a press, the flange comprising a first region and a second region, and
a target configured to receive a punch of the press;
flash annealing the first region, wherein the flash annealing comprises:
heating the first region at a temperature between 360° C. and 440° C. for 5 to 60 seconds to recrystallize the first region, and
cooling, subsequent to the heating, the first region to a temperature of less than 100° C.,
wherein the flash annealing is localized to the first region;
maintaining the blank at room temperature for at least a day subsequent to the flash annealing;
placing the flange of the blank within the blank holder of the press;
stamping the target with the punch of the press subsequent to the maintaining of the blank at room temperature to form a stamped product; and
removing the flange from the stamped product to form an excised product, wherein the excised product is essentially non-recrystallized.
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