Influence of cusp magnetic field configuration on K-TIG welding arc penetration behavior

Experiments have been carried out to test the improving effect of the cusp magnetic field to K-TIG arc penetration ability. The cusp magnetic field was generated with permanent magnets, the configuration parameters, including pole angle and field direction, were changed. Stationary welding experiments were carried out to measure the melting zone and the melting depth. After compressed with the cusp magnetic field, the anode melting zone changed from a circular shape to an ellipse shape, and the melting zone area was reduced. When the magnetic field direction was perpendicular to the arc column, the constraint effect was better than that when the magnetic field direction was parallel. Arc pressure distributions were experimental measured. Magnetic field with smaller pole angle has better constraint effect to the arc in the aspects of smaller melting zone area, increased melting depth, arc voltage and peak value of the arc pressure. These results indicated that the additional cusp magnetic field with less pole angle could further improve the penetration ability of the K-TIG arc.