METHOD OF MANUFACTURING ALUMINUM ALLOY PLATE FOR MOLDING

摘要

An aluminum alloy ingot containing not less than 0.4 % by weight and less than 1.7 % by weight of Si, not less than 0.2 % by weight and less than 1.2 % by weight of Mg, and Al and unavoidable impurities for the remainder is homogenized at a temperature of not lower than 500 DEG C; the resultant product being cooled from a temperature of not lower than 500 DEG C to a temperature in the range of 350-450 DEG C and started to be hot rolled; the hot rolling step being finished at a temperature in the range of 200-300 DEG C; the resultant product being subjected to cold rolling at a reduction ratio of not less than 50 % immediately before it has been solution-treated; the cold rolled product being then solution-treated in which it is retained at a temperature in the range of 500-580 DEG C at a temperature increasing rate of not less than 2 DEG C/s for not more than 10 minutes; the resultant product being subjected to hardening in which it is cooled to a temperature of not higher than 100 DEG C at a cooling rate of not less than 5 DEG C/s. Thus, a method of manufacturing an aluminum alloy plate for molding is provided which has high strength and moldability and an excellent external appearance of a post-molding surface thereof, and which is suitably used as a material for transportation equipment parts, such as an outer plate for automobiles.