Numerical Simulation of Thermal and Residual Stress Field Induced by Three-Pass TIG Welding of Al 2219 Considering the Effect of Interpass Cooling

Abstract

One of the main factors affecting weld joints manufactured using multi-pass welding is the accumulation of high temperature between the finished and subsequent weld pass (Interpass temperature). Consequently, resulting in adverse effects to the mechanical performance of weld, thus, increasing the failure tendency. Therefore, controlling the interpass temperature is crucial to enhance the reliability of the weld joints fabricated using multiple weld passes. In this paper, the finite element method is used to analyze the thermal distribution, residual stresses, and interpass temperature developing due to the three-pass TIG welding of Al 2219. DFLUX user subroutine code was used to simulate the moving weld torch with distributed power density. An interpass cooling process was established, which significantly decreases the interpass temperature to an acceptable limit for Aluminum alloys. The experimental measurements of temperature and residual stresses were used to validate the numerical model. Finally, the effect of welding heat on the grain size of heat affected zone was analyzed using the electron backscatter diffraction.