| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a high Mg Al-Mg based alloy sheet by which Al-Mg based intermetallic compounds produced in a heat history step after being subjected to twin roll type continuous casting are suppressed and press formability of the high Mg Al-Mg based alloy sheet is improved as a result. SOLUTION: The method for producing an aluminum alloy thin sheet for forming with a sheet thickness of 0.5 to 3 mm includes obtaining an aluminum alloy sheetlike ingot with a sheet thickness of 1 to 13 mm containing >8 to 14% Mg according to a twin roll type continuous casting process, and subjecting the ingot to cold rolling, wherein the casting is performed in such a manner that after teeming to the twin rolls, the average cooling velocity till the solidification of the central part in the sheetlike ingot is controlled to≥50°C/s, further, in the subsequent step, when the sheetlike ingot or thin sheet is heated to≥400°C, the average temperature rising rate at which the temperature of the central part in the ingot or thin sheet lies in the range of 200 to 400°C is controlled to≥5°C/s, and when the sheetlike ingot or thin sheet is cooled from a high temperature exceeding 200°C, the cooling is performed in such a manner that the average cooling velocity till the temperature of 200°C is controlled to≥5°C/s, so that press formability including the homogeneity of the sheet is improved. COPYRIGHT: (C)2006,JPO&NCIPI
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