| 摘要 |
PROBLEM TO BE SOLVED: To provide an excess Si type 6,000 series Al alloy sheet in which the occurrence of rough surface at panel forming is prevented by further making average grain size after solution heat treatment and quenching treatment fine to≤20μm and also to provide its manufacturing method. SOLUTION: The ingot of an Al-Mg-Si type aluminum alloy having a composition which contains 0.4 to 1.3% Si, 0.2 to 1.2% Mg, 0.01 to 0.65% Mn, and 0.001 to 1.0% Cu and in which the value of Si/Mg by mass ratio is made to≥1 is subjected to homogenization heat treatment at≥500°C and temporarily cooled to room temperature. Subsequently, the ingot is reheated to 350 to 470°C and hot rolling is started. In the stage of a hot rolled plate, a coarse Mg<SB>2</SB>Si intermetallic compound of≥1.0μm average grain size is precipitated in the structure in an amount of≥0.6% per mm<SP>2</SP>by area ratio and average grain size after subsequent solution heat treatment and quenching treatment is made fine to≤20μm. COPYRIGHT: (C)2004,JPO
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