Influence of welding parameters on the weld properties in Friction stir spot welding of aluminium alloys of varying thicknesses

Abstract

Joining of dissimilar materials with different thicknesses in automobile and shipbuilding industries by conventional arc welding methods is a challenge due to unequal stress distribution during welding. The problem of imbalanced stress can be reduced or avoided in solid state welding methods. In the present work, aluminium alloys of dissimilar thickness are joined by Friction stir spot welding, FSSW. The feasible welding conditions were determined by Response surface methodology. The maximum strength of 6.204 kN was obtained at 1000 RPM, 0.02 mm/s plunge speed and thread pin profile. The rotational speed was identified as the vital parameter that influenced the joint strength by analysis of variance. The Artificial neural network was used to predict the mechanical strength of the weld joints. The microstructure analysis revealed that tool profile significantly influenced the hook shape. The microhardness survey revealed that the stir zone hardness was higher than the hardness at the heat-affected zone due to severe plastic deformation.