A new discovery of arc shape in pulsed ultrasonic wave assisted TIG welding

An entirely new change-rule of an arc shape was found in the pulsed ultrasonic assisted tungsten-electrode inert gas welding process (PU-TIG), i.e., the arc shape had an obvious characteristic of periodic changes under the actions of a pulsed ultrasonic wave in PU-TIG. However, periodic changes of the arc shape were different between the arc white bright zone and the arc dark bright zone. The varying process of the arc shape was that the arc shape went through from expansion to contraction and re-expansion. Meanwhile, the constantly changing acoustic radiation force and electromagnetic force were the main cause of the periodic change of the arc shape in the PU-TIG welding process.