ALUMINUM ALLOY SHEET AND METHOD FOR MANUFACTURING THE SAME

摘要

An aluminum alloy sheet is manufactured by preparing a slab having a thickness of 5 to 15 mm with a continuous casting machine by a continuous casting process using molten alloy containing 0.40% to 0.65% of Mg, 0.50% to 0.75% of Si, 0.05% to 0.20% of Cr, and 0.10% to 0.40% of Fe, the remainder being Al, those components being essential elements optionally up to 0.15% Cu, 0.10% Ti; ; winding the slab into a coil; hot-rolling or directly coiling up the slab; cold-rolling the resulting slab into a sheet; subjecting the resulting sheet to solution heat treatment with a continuous annealing furnace; and then pre-aging the resulting sheet. The aluminum alloy sheet has the same composition as that of the molten alloy and has a grain size of 10 to 25 µm. Although the aluminum alloy sheet is superior in bake hardenability, bendability, and surface quality (orange peel), that is, the aluminum alloy sheet has high quality, tAn aluminum alloy sheet is manufactured by preparing a slab having a thickness of 5 to 15 mm with a continuous casting machine by a continuous casting process using molten alloy containing 0.40% to 0.65 of Mg, 0.50% to 0.75% of Si, 0.05% to 0.20% of Cr, and 0.10% to 0.40% of Fe, the remainder being Al, those components being essential elements, winding the slab into a coil; hot-rolling or directly coiling up the slab; cold-rolling the resulting slab into a sheet; subjecting the resulting sheet to solution heat treatment with a continuous annealing furnace; and then pre-aging the resulting sheet. The aluminum alloy sheet has the same composition as that of the molten alloy and has a grain size of 10 to 25 µm. Although the aluminum alloy sheet is superior in bake hardenability, bendability, and surface quality (orange peel), that is, the aluminum alloy sheet has high quality, the sheet can be manufactured with low cost.