| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously improve both the castability and elongation of an aluminum alloy while its strength is maintained, to enable plastic working to a casting stock as-cast cast by the alloy at about an ordinary temp. and furthermore changing and stabilizing the mechanical properties such as tensile strength, proof stress, hardness, elongation or the like at the bottom part of the cast stock subjected to the plastic working. SOLUTION: A casting stock composed of a high ductility aluminum allay contg., by weight, 0.5 to 2.5% Mn components, 0.1 to 1.5% Fe components, 0.01 to 1.2% Mg components, and the balance aluminum with inevitable impurities and having a bottomed shape approximately same as that of an AT drum is cast, and thereafter, the bottom part 8' (thickness h0) as-cast is subjected to upsetting working (plastic working) at about an ordinary temp. to form the bottom part 8 (thickness h) of the AT drum. At this time, the upsetting rate is regulated to >=20% ((h0-h)/h0×100>=20).
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