PURPOSE: To produce the high-strength Al alloy plate for press forming having excellent press formability and strength after coating and baking by subjecting the slab of an Al alloy having a specific compsn. to a homogenization heat treatment, then working this slab to a plate material by hot rolling and cold rolling, and further heat treating the plate material under specific conditions.
CONSTITUTION: The slab of the Al alloy contg., by weight %, 1.6 to 5.5% Mg, 0.42 to 1.5% Si, 0.51 to 2.5% Cu, 0.61 to 2.8% Zn, 0.005 to 0.15% Ti, 0.0002 to 0.05% B, and 0.03 to 0.4% Fe, and one or ≥2 kinds among 0.01 to 0.20% Zr, 0.01 to 0.30% Cr, 0.02 to 0.18% Mn, and 0.01 to 0.30% V, is subjected to one stage or many stages of the homogenization heat treatments in a 480 to 560°C temp. range. This slab is worked to the plate material having a prescribed thickness by the hot rolling and cold rolling and is then subjected to the heat treatment consisting in heating to 440 to 560°C at ≥3°C/sec heating rate and holding for ≤120 seconds, then cooling at ≥2°C/sec cooling rate.
FUJITA TAKESHI
MITAO SHINJI
MINAGAWA KUNINORI
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