PURPOSE: To improve the formability and weldability of an aluminum alloy sheet and to reduce its cost by melting an Al scrap raw material, adding Mg thereto to regulate its components, thereafter executing casting, rolling and continuous annealing and furthermore applying it with lutricating surface coating.
CONSTITUTION: An Al scrap contg., by weight, 0.3 to 2.0% impurity elements of Fe and Si is used as a raw material. This raw material is melted, and the components are regulated to regulate the content of Mg into 3 to 10%. Or, it is moerover incorporated with one or ≥two kinds among Cu, Mn, Cr, Zr and Ti respectively by 0.02 to 0.5%. The Al alloy having the same compsn. is cast and is subjected to hot rolling, cold rolling and continuous annealing to obtain an Al alloy sheet having ≥31kgf/mm2 tensile strength. The surface of the Al alloy sheet is applied with lubricating surface coating to regulate the sliding resistance of the Al alloy sheet into ≤0.11. Thus, the high strength Al alloy sheet excellent in formability and resistance spot welding continuous spotting properties can be obtd.
FURUKAWA ELECTRIC CO LTD:THE