| 摘要 |
<p>The present invention provides a method of producing a hardened aluminum alloy sheet comprising the steps of casting an aluminum alloy containing 4.0 to 6.0% Mg in a conventional manner, homogenizing, hot rolling, cold rolling, intermediate annealing and stabilizing treatment, the improvement which comprises: the aluminum alloy is provided as an Al-Mg-Cu alloy containing, in addition to Mg, 0.05 to 0.50% Cu; and the Al-Mg-Cu alloy is subjected to a final intermediate annealing comprising heating to temperatures of 350 to 500 DEG C and rapid cooling to temperatures of 70 DEG C or less at a cooling rate of 1 DEG C/sec or more and a finishing cold rolling with a reduction of at least 50%, followed by the stabilizing treatment, thereby providing a hardened aluminum alloy sheet having a superior corrosion resistance together with high levels of strength and formability. In the above production method, the finishing cold rolling with a reduction of at least 50% may be followed by coating and baking operations carried out under application of tension.</p> |
