Determination of arc pressure and current density on the molten pool surface in plasma arc welding

A unified numerical model is developed to couple the plasma arc,weld pool and keyhole in a self consistent way. The plasma arc/anode interface and the melt/solid interface are treated specially,the VOF method is used to trace the moving keyhole wall,and the fluid flow and heat transfer in both the plasma arc and weld pool are numerically simulated. The distributions of current density and arc pressure on the weld pool surface during the keyhole formation process are analyzed using the coupled model. The predicted arc pressure and current density are compared with the experimentally measured results,and both are in good agreement.