Friction Stir Spot Welding (FSSW) of Automotive Steels

The Advanced High Strength Steels (AHSS) - the new generation of automotive steels with excellent mechanical properties - is an integral part of light weight high performance design solutions targeting low end high volume production cars. Extensive use of these steels, however, is restricted by their poor weldability with respect to Resistance Spot Welding (RSW), the most popular process for joining sheet metals in the automotive industry. In this context, Friction Stir Spot Welding (FSSW) - a variant of Friction Stir Welding (FSW) - is being considered as an alternative process for joining light weight automotive alloys in similar and dissimilar combinations. Although FSSW of Al and Mg alloys have been extensively investigated, only a few preliminary reports of basic characteristics of AHSS joints are available. With this background, the current study attempts to address some of the prevailing issues to promote large scale commercialization of the FSSW process for joining AHSS. The study establishes the capability of FSSW process to produce acceptable joints with excellent mechanical properties within a productive time cycle, in similar as well as dissimilar steel combinations.