A mathematical model of heat transfer and fluid flow in the gas metal arc welding process

Abstract

Mathematical models of the Gas Metal Arc Welding (GMAW) process may be employed to predict welding process parameters to obtain the required weld-bead geometry and to study the effects of weld process parameters on the weld-bead dimensions. In this work, an unsteady two-dimensional (2D) axisymmetric model was developed for investigating the heat and fluid flows in weld pools and determined the weld bead geometry, and the velocity and temperature profiles for the GMAW process. The mathematical formulation considers four driving forces for weld pool convection: electromagnetic; buoyancy; surface tension; and drag forces. The formulation also deals with the molten metal droplets. The equation was solved using a general thermofluid-mechanics computer program, PHOENICS code, which is based on the SAMPLE algorithm. The results of computation have shown that the electromagnetic and surface tension forces as well as the molten metal droplets have a major influence in shaping the weld-pool geometry. Good agreement is shown between the predicted and experimentally determined weld-bead dimensions.