A study of shear friction factor in friction stir welding for developing a finite element model and its importance in the context of formation of defect free and defective weld

Abstract

Friction Stir Welding (FSW) and Friction Stir Processing (FSP) are novel technologies where FSW is used to join materials in solid state and FSP is used to eliminate defects and refine the micro-structure of a cast material. Though it has been successfully demonstrated for few commercial alloys, technique lacks an efficient and effective method to track optimized process parameters required to obtain good weld. Finite element (FE) modeling seems to be a promising approach for the same. The paper emphasizes on quantification of friction boundary condition and its impact on formation of welds. It is found that stick condition between tool and work-piece is essential to obtain consolidated welds. Further, FE simulations for temperature predictions were validated with experimental results with shear friction factor of one. The importance of interfacial stick was corroborated with plasticine experiments.