Numerical simulation of current density in gas tungsten arc welding including the influence of the cathode

A two-dimensional axisymmetric numerical model including the influence of cathode is developed to describe the heat transfer and fluid flow in gas tungsten arc (GTA) welding arcs. The current continuity equation has been solved with the combined arc plasma-cathode system, independent of the assumption of current density distribution on the cathode surface which was essential in the previous studies of the arc plasma. It is indicated that the predicted arc column temperatures agree well with existing experimental data. The effects of current, electrode tip geometry and arc length on the anode current density distributions are analysed using the developed model, and the current density distributions calculated at the anode are compared with the experimental data measured by the probe method.