| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy rolled sheet for anodic oxidation treatment stably showing gray even in the case of a thin anodically oxidized film of about 10μm, further excellent in bending workability and moreover having strength equal to that of the conventional material. SOLUTION: An Al alloy ingot contg., by weight, 1.3 to 1.5% Mn, 0.4 to 1.2% Mg, 0.1 to 0.2% Fe and 0.05 to 0.15% Si is subjected to heating treatment at 580 to 630 deg.C, then, hot rolling is started at the ingot heating temp. or below and is finished at <=300 deg.C, if required, cold rolling is executed, and thereafter, it is subjected to process annealing of 400 to 600 deg.C×<=10 min under the conditions of rapid temp. raising and rapid cooling and is moreover subjected to cold rolling. In this way, a rolled sheet in which Al-Mn series acicular precipitates of 2 to 8μm are precipitated at a density of 2000 to 8000 pieces/mm<2> , further having <=80μm average grain size and >=95 N/mm<2> proof stress is obtd.
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