Optical Observation of Cathode Spot in AC Tungsten Inert Gas (TIG) Welding on Aluminum Plate using Helium

摘要

The cleaning action in AC TIG welding is attributed to the oxide film removal process caused by cathode spots. Clarifying the behavior mechanism of these cathode spots could enable the control of the cleaning action. However, the behavior mechanism of cathode spots has not yet been experimentally clarified. This study reports that observations by high-speed video camera revealed the absence of cathode spots at the center of the molten pool for AC TIG welding using helium as the shield gas on aluminum plates.