Finite element simulation of exit hole filling for friction stir spot welding - A modified technique to apply practically

Abstract

Friction Stir Spot Welding (FSSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and/or a probe. Though it has proven its potential in joining difficult to weld materials, one of the drawbacks of process is prevalence of exit hole at the end of the process. In the recent past new techniques have been developed to eliminate this draw back by filling this unwanted hole. Determining the appropriate tool design and parameters to fill a hole for given situation is a challenge. The article demonstrates the effective method of obtaining these desired parameters a priory. A three dimensional (3D) model is developed in finite element (FE) commercial code DEFORM 3D/Implicit. It was found that internally filleted shoulders help in filling of holes. The obtained optimized process parameter (tool rotation speed of 900rpm, plunge velocity of 30mm/sec and plunge depth of 0.2 mm) for AA2024 plate (5mm thick) have potential to reduce number of experiments. � 2014 The Authors.