Reignition Phenomena in AC TIG Welding Arc with a Rectangular Current Pulse. Report (I)

Abstract

When the AC TIG Arc Welding Processes are applied to base metals such as aluminum, copper, magnesium, etc, the higher frequencies which are superimposed to steady the arc give rarely rise to radio interferencies, the complete means, however, to solve the troubles have not yet been found.
Therefore, in respect of this complicated problems, we have been studying the reignition phenomena on AC TIG arc. This study was carried out to make clear the reignition phenomena with a rectangular current pulse. When a rectangular voltage pulse was impressed to the gap at the zero current phase, the arc reignitions at every reverse polarity were caused by the pulsed arc discharge which followed an abnormal glow discharge having a duration of a few microseconds and a gap voltage of a few hundred volts. Then it will be supposed that the pulsed arc discharge is able to maintain the ionized region between the electrodes for appreciable periods after current zero.