| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for easily making an Al alloy sheet material effective in particular for automotive applications. SOLUTION: The invertion relates to the process for making an Al alloy sheet in which strength after T4 treatment is 90 to 175 MPa and strength after T8 treatment is≥170 MPa, in which an alloy slab is produced in a belt casting machine by casting an Al alloy, hot rolling and cold rolling the slab to form a sheet, solution heat treating the sheet to re-dissolve precipitated particles, and cooling the sheet. The process is characterized in that the alloy contains Mg and Si in amounts falling within the area ABCDEF of figure 1, and amounts of Cu between the contours shown by broken lines in Figure 1 and 0.3 wt.% in area BHGI and 0 wt.% in areas HAFG and IEDC of Figure 1 corresponding to the amounts of Mg and Si, and the balance Al; and in that the heat is extracted from the alloy in the belt casting machine at a rate falling within the shaded band in Figure 3 corresponding to a freezing range of the alloy, and the alloy is subjected to heat treatment including solution heat treatment. COPYRIGHT: (C)2008,JPO&INPIT
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