Optimization of welding conditions for friction stir spot welding of A6063S-T5 with composite coated films using a triangular prism-shaped tool

Friction Stir Welding (FSW), which was developed at TWI in 1991, is a solid-phase welding process capable of joining linear and point welds, and is being put to practical use in the automotive, aerospace, and other industries for the purpose of weight reduction and multi-materials. In this paper, the effects of each factor on joint strength in friction stir spot welding are clarified using statistical methods, and optimized joint conditions are proposed. Specifically, the optimal joining structure is experimentally clarified for aluminum materials with composite coatings by utilizing the design of experiment method in terms of the degree of influence of tool geometry and tool motion. Only the shape of the tool's probe is triangular prism because it is known to be effective in bonding composite films to the material.