NUMERICAL-SIMULATION OF CURRENT-DENSITY IN GAS TUNGSTEN ARE 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 are (GTA) welding arcs. The current continuity equatio n has been solved with the combined are plasma-cathode system, indepen dent of the assumption of current density distribution on the cathode surface which was essential in the previous studies of the are plasma. It is indicated that the predicted are column temperatures agree well with existing experimental data. The effects of current, electrode ti p geometry and are length on the anode current density distributions a re analysed using the developed model, and the current density distrib utions calculated at the anode are compared with the experimental data measured by the probe method.