a process is described for producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles . an aluminum alloy containing 0 . 50 to 0 . 75 by weight mg , 0 . 7 to 0 . 85 % by weight si , 0 . 1 to 0 . 3 % by weight fe , 0 . 15 to 0 . 35 % by weight mn , and the balance al and incidental impurities , is used and is semi - continuously cast into ingot . the cast alloy ingot is subjected to hot rolling and cold rolling , followed by solution heat treatment of the formed sheet . the heat treated sheet is quenched to a temperature of about 60 – 120 ° c . and the sheet is then coiled . this coil is then pre - aged by slowly cooling the coil from an initial temperature of about 60 – 120 ° c . to room temperature at a cooling rate of less than 10 ° c ./ hr .