PURPOSE: To prevent the generation of patterns on the surface of a bright Al alloy plate material in the anodization after hot rolling in the stage of producing said plate by subjecting the plate to preliminary rolling under specific conditions prior to the hot rolling.
CONSTITUTION: An ingot of a bright Al alloy contg. (0.2W1.2)% Mg, (0.05W0.2)% Cu or further (0.05W0.45)% Mn is heated to ≥570°C, whereby it is homogenized and is aggregated and coarsened of intermetallic compds. Prior to hot rolling, the ingot is subjected to preliminary rolling at ≥15% draft and ≤350°C, then it is hot-rolled to a plate material. Despite anodizing, such bright Al alloy plate material does not form belt-, line- or streak-like patterns that degrade aesthetic value on the surface.
OZAWA YOSHIHARU
FUCHIZAWA GOROU
