Double-pass process was newly performed to a friction stir welded (FSWed) A3003 aluminum alloy /SUS304 stainless steel dissimilar lap joint in order to improve the asymmetry of the FSWed joint. A sound symmetrical joint was produced by running the tool again at the bead which ˆrstly produced by FSW. Tensile strength of specimens was improved by leaving the tool distance from 2 mm to 5 mm where both edges of the stirred zone were advancing side (AS-AS joint). Micro-tensile test revealed that most of the stirred zone in the AS-AS joint with the tool distance of 5 mm fractured at A3003 base metal.
