Numerical investigation of the effects of driving forces on weld pool convection and thermal stress in a GTAW process

This research article aims to obtain optimal weld integrity and avoid material fracture due to high welding temperatures. Computational fluid dynamics (CFD) and the finite element method (FEM) were used to study the gas tungsten arc welding (GTAW) process. The heat source distribution and the convection movement in the melted pool were taken into account. A two-dimensional (2D) numerical model was developed to simulate the GTAW process and applied to 304 L stainless steel. The effects of welding operating parameters, such as voltage and current, were examined. The simulation showed that the capillary force presented by Marangoni convection mainly affects the weld pool geometry. Therefore, as a result, increasing the welding power and particularly the current intensity leads to the rapid growth of the melted zone, which may induce high residual stress and risk of metal fracture; otherwise, the dimensions of the melted zone in an arc welding process do not grow with the same shape or speed and depend on the welding processing parameters. Finally, the computed weld profile and thermal stress showed good agreement compared to experimental results.