| 摘要 |
PROBLEM TO BE SOLVED: To obtain an aluminum alloy ingot in which the crystal grains therein are refined, and also, the standard deviation of the crystal grains is reduced. SOLUTION: When an aluminum alloy molten metal having a componential composition comprising, by mass, 4 to 12% Zn, 1 to 3% Mg and 0.5 to 3% Cu, and further, if required, comprising≤0.3% Cr and≤0.3% Zr, and the balance Al with inevitable impurities, and in which the content of Ti as impurities is limited to≤0.01% is subjected to DC casting, electromagnetic stirring is performed in the form only of a centripetal magnetic force, further, the casting is performed in such a manner that the solid phase ratio of a solid-liquid coexistent part electrically stirred within a rapid cooling mold in the DC casting is controlled to 0.2 to 0.6 so as to obtain an aluminum alloy ingot having a metallic structure where the average value of the crystal grain sizes in the central part of the ingot is≤50μm, and also, the standard deviation of the crystal grain sizes is≤12μm. COPYRIGHT: (C)2010,JPO&INPIT |
