| 摘要 |
PROBLEM TO BE SOLVED: To provide an Al-Mg-Si alloy sheet for forming superior in hem bendability, for a body sheet in automobiles, or the like. SOLUTION: The Al alloy sheet includes 0.3-1.0% Mg, 0.3-1.2% Si, one or more elements of Mn, Cr, Zr, V, Fe, Ti, and Zn, in a small amount, 1.0% or less Cu, and the balance Al, and has a cubic orientation density of twice as much as or more than that in a random oriented sample, earing rates in 0 degree and 90 degrees of 0.1% or more, and an average crystal grain size of 100μm or less, over the whole thick plate. The Al alloy sheet further has an orientation density of cubes having a rotational relation around the normal line, which exist in a region from the sheet surface to 1/4 depth of the total sheet thickness, in amount of twice as much as or more than that in a random oriented sample. The manufacturing method comprises hot-rolling a slab of the above aluminum alloy at 500-320°C in a stage of 150-80 mm, at 450-270°C in a stage of 80-15 mm, and at a finishing temperature of 350-180°C in a finishing stage of 1.5-8 mm by thickness, cold-rolling it with a reduction of 30% or more, subsequently solution-treating it at 480°C or higher for 5 minutes or less, then cooling it to a range of 50°C to lower than 150°C at 100°C/min or higher, and subjecting it to stabilization treatment of successively holding it in the same temperature range for two hours or more, or then further subjecting it to final heat treatment at 170-280°C for 5 minutes or shorter. COPYRIGHT: (C)2003,JPO
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