6000 High-strength 6000-based alloy thick plate having uniform strength in plate thickness direction and method for manufacturing the same

摘要

The present invention contains Si, Mg, Ti, Fe in a predetermined amount, the balance of Al and unavoidable in high-strength aluminum alloy plate made of aluminum alloy of the impurity, the Mg 2 Si in less than 3 ㎛ circle-equivalent diameter of the plate thickness central portion The area ratio of Mg 2 Si is 0.45% or less, and the area ratio of Mg 2 Si in the region of 20 mm±1.5 mm from the plate surface in the plate thickness direction to 3 µm or more of the equivalent circle diameter is 3 µm or more of the equivalent circle diameter in the central portion of the plate thickness. more than 1.2 times the area ratio of Mg 2 Si is a high-strength aluminum alloy plate having a tissue material which is 3.0 times or less. This aluminum alloy thick plate has sufficient strength, and the uniformity of strength in the plate thickness direction is good. The aluminum alloy thick plate of the present invention can be manufactured by performing a quenching process after solution heat treatment, cooling so as to generate an appropriate temperature difference between the plate thickness center portion and the surface.