PRODUCTION OF ALUMINUM-MAGNESIUM ALLOY FREE FROM GENERATION STRETCHER STRAIN MARK AT THE TIME OF FORMING

摘要

PROBLEM TO BE SOLVED: To produce an Al-Mg alloy good in formability by subjecting an Al-Mg alloy contg. a specified amt. of Mg to hot rolling, thereafter executing specified rolling including specified process annealing and then subjecting the same to specified stabilizing annealing. ;SOLUTION: An ingot obtd. by casting an Al-Mg alloy contg., by weight, 1.5 to 4% Mg is subjected to homogenizing heat treatment preferably at about 500 to 550°C and is thereafter subjected to hot rolling at about 300 to 550°C. This hot rolled stock is subjected to cold intermediate rolling at ≥40% working ratio, is next subjected to batch type or continuous process annealing at about 300 to 550°C (excluding the range of 300 to 500°C) and is moreover subjected to finish rolling at ≥40% working ratio. Then, this cold rolled stock is subjected to stabilizing annealing at 150 to 250°C in which softening degree shown by the formula of softening degree (σy₀-σy)×100≈σy₀ (σy⁰ and σy denote the proof stress of the stock respectively before and after the stabilizing annealing) is regulated to ≥10% to regulate the grain size to 10 to 40μm.;COPYRIGHT: (C)1997,JPO