Spatial stabilization of arc discharges in pulsed gas tungsten arc welding

Abstract

The aim of this study was to investigate the influence of the discharge parameters on the initial spatial instability of arcs after their initiation by the non-contact method in single-pulse electrode-negative gas tungsten arc welding. The investigated parameters were the P_peak peak arc pressures, the T durations for achieving the peak arc pressure, and the P_final arc pressures at the end of current pulses. It was found that increasing the current amplitudes from 50 to 200 A enhanced mean both the P_peak values (from 0.25 to 4.00 kPa) and the P_final levels (from 0.16 to 1.72 kPa). Enhancing the electrode diameters from 1.0 to 2.4 mm increased these experimental output parameters from 1.85 to 1.99 kPa and from 0.57 to 1.23 kPa, respectively, while they were decreased from 2.32 to 1.47 kPa and from 1.19 to 0.62 kPa after changing the sharpening angle of their tips from 30° to 90°. The period of the spatial instability of arc discharges was shortened from 14.4 to 5.8 ms by increasing the current amplitudes from 50 to 200 A. However, enhancing the electrode diameters from 1.0 to 2.4 mm increased its duration from 9.2 to 12.0 ms. It was also prolonged from 6.2 to 16.8 ms after changing the sharpening angle of the electrode tips from 30° up to 90°. The shortest duration of the arc stabilization period of 5 ms was observed when using the WL15 non-consumable electrode, while it was the longest (35 ms) for the WP one.