EFFECT OF WELD POOL DEFORMATION ON WELD PENETRATION IN STATIONARY GAS TUNGSTEN ARC-WELDING

The effect of weld pool surface deformation on weld joint penetration under the arc pressure has been studied in stationary gas tungsten arc welding (GTAW), by considering the four driving forces for weld pool convection: electromagnetic force, buoyancy force, aerodynamic drag force, and surface tension force at the weld pool surface. In the numerical simulation, difficulties associated with the irregular shape of the deformed weld pool surface and the moving liquid-solid interface have been successfully overcome by adopting a boundary-fitted coordinate system, which eliminates the analytical complexity there. This method also has the capacity to handle the time-dependent changing solution domain of the moving boundary problem and could be applied effectively to this transient weld pool development problem with the phase change condition and moving boundary, such as at the deformed weld pool surface and the liquid-solid interface.