Bobbin tool friction stir welding: a review

ABSTRACT

Friction stir welding is a solid-state welding technique for joining similar and dissimilar material. Bobbin tool friction stir welding (BTFSW) is a variant of the conventional friction stir welding process (CFSW). Compared with conventional FSW, BTFSW eliminates all limitations of CFSW using a two shoulders configuration. Now, the need has arisen to review the work done on BTFSW to provide broader aspects of the technique to researchers. This paper aims at providing comprehensive insight on the BTFSW. The paper pays critical attention to tool material selection, design features of shoulder and pin surfaces, microstructure evolution, mechanical characterisation, derivatives, and challenges in this technique. Further, welding defects and future scope of BTFSW are also addressed in this paper.