Effects of current pulsation at ultra-high frequency on physical aspects of the arc and its implications in the weld bead morphology in the GTAW process

Advances in the dynamic response of welding power sources have allowed the use of pulsed current at frequencies above 20 kHz. However, the effects of pulsing the welding current at these high-frequency levels are not well known, especially those associated with the voltaic arc. Thus, the aim of this study was to carry out experimental research on a pulsating welding current at ultra-high frequencies focusing on two important voltaic arc parameters in gas tungsten arc welding processes: arc voltage and arc stagnation pressure. The tests were performed with a welding current pulsed at frequencies of 20 to 80 kHz and amplitudes of 0 to 50 A. The results indicated that pulsing the current at ultra-high frequencies leads to a reduction in the average arc voltage, increasing the stagnation pressure and the arc constriction. Regarding the weld bead dimensional aspects, greater values of width and penetration were obtained when the high-frequency current pulsation was applied.