Friction Stir Spot Welding (FSSW) of AA1100 Aluminum Alloy — Parameters Optimization and Sensitivity

Friction stir spot welding (FSSW) is a single spot solid state joining process and has widely been employed in transportation industries especially for joining lightweight materials such as aluminum, copper and magnesium alloys. FSSW process parameters such as tool rotational speed, plunge rate, plunge depth, dwell time play major role in determining the strength of the joints. A central composite rotatable design with four factors and five levels has been chosen to minimize the number of experimental conditions. An empirical relationship is established to predict the tensile shear fracture load (TSFL) of friction stir spot-welded commercial grade (AA1100) aluminum alloy by incorporating independently controllable above said process parameters. Response Surface Methodology (RSM) is applied to optimize the process parameters to attain maximum shear strength in the spot welded lap joints. Sensitivity analysis also carried out to study the impact of process parameters on output.