Aluminum Welding Guide

When heat treatable aluminum alloys are welded, they lose a significant amount of their mechanical properties in the heat affected zone. If the base metal being welded is in the -T4 temper, much of the original strength can be recovered after welding by post-weld aging. If the base metal is welded in the -T6 temper it can be solution heat treated and aged after welding which will restore it to the -T6 temper. Depending on which filler metal is used for welding, post-weld heat treating and aging may cause problems. If the filler metal does not respond to heat treatment and aging the same way as the base metal, the weld joint may exhibit mechanical properties below those of the base metal. Due to stress concentrations in the weld itself, this is not a desirable condition. Therefore, if post-weld heat treatment and aging are performed, the filler metal selected is critical. Contact Hobart and get metallurgical advice on which filler metals are best suited for your application.