The aim of this research was to investigate the effect of heat treatment on mechanical properties of 6063 aluminum alloy for a single pass of Activated Tungsten Inert Gas (ATIG) welding. and to determine the optimum parameters for heat treatment for the ATIG welded 6030 aluminum alloy. welded samples were tested for tensile strength and hardness. Preheat treatment and Artificial Ageing were performed on the samples at different conditions. I used the Taguchi tool to optimize the best parameters treatment to get high mechanical properties.