Numerical Simulation of Welding Influence on Tensile Strength and Residual Stress of AISI 304 Butt Joints
Keywords:Tungsten Inert Gas (TIG) welding, residual stresses, transient temperature, tensile test, numerical simulation
Fusion welding is a metallurgical fusion process in which parts assembled by heating the connecting edge above the melting temperature and then compacting it. The present study was designed to determine the effect of TIG welding on the thermomechanical performance of AISI 304 butt joints. The aim can be achieved by employing three-dimensional analysis with non-linear thermo-mechanical simulations for AISI 304 stainless steel using finite element analysis. Moreover, the failure mode of butt joints under tensile stress test has been obtained numerically using finite element analysis. This study has shown that when the welding current increases, the heat input increased and the fusion zone area is decreased. The increase in welding current (increased heat input) leads to a reduction in the cooling rate and an increase in the grain size of the weld metal and the region affected by heat (heat affected zone). An increase in welding current increases the width of the region affected by heat and increases the volume fraction and decreases microhardness. The results showed that the longitudinal residual stress distribution is uniform along the weld line with similar pattern with transversal residual stress. Therefore, due to increase cooling rate, the microhardness has a maximum value at the boundary between the fusion zone and heat-affected zone. Nevertheless, it turned out that all coupons tested for butt joints fractured in the heat-affected zone (HAZ).