Abstract: An Al—Mg—Si—Cu aluminum alloy plate excelling in strength and formability and exhibiting improved filiform corrosion resistance which is suitably used for automotive body panels. The aluminum alloy plate contains 0.25-0.6% of Mg (mass %, hereinafter the same), 0.9-1.1% of Si, 0.6-1.0% of Cu, and at least one of 0.20% or less of Mn and 0.10% or less of Cr, with the balance consisting of Al and impurities, wherein the number of Q phases (Cu—Mg—Si—Al phases) with a size of 2 &mgr;m or more in diameter present in a matrix is 150 per mm2 or more. The aluminum alloy plate is fabricated by homogenizing an ingot of an aluminum alloy having the above composition at 530° C. or more, cooling the ingot to 450° C. or less at a cooling rate of 30° C./hour or less, hot-rolling the ingot, cold-rolling the hot-rolled product, and providing the cold-rolled product with a solution heat treatment.

Abstract: An aluminum alloy plate for an automobile has a chemical composition containing 0.8 to 1.5% by mass of Si, 0.4 to 0.7% by mass of Mg and 0.5 to 0.8% by mass of Cu. The crystal grain size is 10 to 40 &mgr;m. Cu content obtained by analyzing the outermost surface of the aluminum alloy with an oxide film according to X-ray photoelectron spectroscopy (XPS) is {fraction (1/10)} to ½ of the Cu content of the bulk of the aluminum alloy plate.

Abstract: An aluminum alloy plate for an automobile has a chemical composition containing 0.8 to 1.5% by mass of Si, 0.4 to 0.7% by mass of Mg and 0.5 to 0.8% by mass of Cu. The crystal grain size is 10 to 40 &mgr;m. Cu content obtained by analyzing the outermost surface of the aluminum alloy with an oxide film according to X-ray photoelectron spectroscopy (XPS) is {fraction (1/10)} to ½ of the Cu content of the bulk of the aluminum alloy plate.

Abstract: An Al—Mg—Si—Cu aluminum alloy plate excelling in strength and formability and exhibiting improved filiform corrosion resistance which is suitably used for automotive body panels. The aluminum alloy plate contains 0.25-0.6% of Mg (mass %, hereinafter the same), 0.9-1.1% of Si, 0.6-1.0% of Cu, and at least one of 0.20% or less of Mn and 0.10% or less of Cr, with the balance consisting of Al and impurities, wherein the number of Q phases (Cu—Mg—Si—Al phases) with a size of 2 &mgr;m or more in diameter present in a matrix is 150 per mm2 or more. The aluminum alloy plate is fabricated by homogenizing an ingot of an aluminum alloy having the above composition at 530° C. or more, cooling the ingot to 450° C. or less at a cooling rate of 30° C./hour or less, hot-rolling the ingot, cold-rolling the hot-rolled product, and providing the cold-rolled product with a solution heat treatment.