Experimental Investigations and Thermo Mechanical Modelling of Friction Stir Welding of Heat Treatable Aluminium Alloy

Abstract

Friction stir welding (FSW) is a relatively new welding process where a rotating non-consumable tool is used to join two materials through high-temperature deformation. An attempt has been made to predict the temperature at weld line, and analysis was carried out by module available in ANSYS.

The suitability of ANSYS for weld line temperature prediction has been established by comparing theoretical model and experimental work available in the literature. Subsequently, same theoretical model is used in ANSYS to predict weld line temperature both in air and immersed FSW. Weld line temperature has been found by using mild steel backing plate. The temperature found by regression analysis in air and immersed FSW are 406.31°C and 364.20°C respectively, and simulation temperatures are 410.719°C and 354.089°C respectively. The results of the simulation are in good agreement with that of results obtained by experimentally.

Thermo-mechanical analysis of FSW of AA2014-T6 has been attempted to find out residual stresses developed both in air and immersed FSW. The effect of backing plate has also been evaluated on residual stresses and microstructure development in both the condition. The compressive residual stresses in longitudinal direction in air and immersed FSW are 1070 MPa and 881 MPa respectively, and in transverse direction 1140 MPa and 935 MPa respectively, by using mild steel backing plate. It has been observed that for various backing plate used for experimentation maximum residual stresses are in transverse direction compared to longitudinal direction.