Effect of Ultrasonic Vibration on Unmixed Zone Formation

Abstract

Ultrasonic vibration was introduced into the molten super-austenitic-stainless weld metal during the shielded metal arc welding process. It was observed that the unmixed zone in the weld metal was completely eliminated by high-intensity ultrasonic vibrations. This is mainly due to a complete mixing of the molten filler metal and base metal, at the freezing front, caused by the acoustically induced cavitation and streaming. The elimination of the unmixed zone can significantly enhance the corrosion resistance of the weldment because the unmixed zone is the preferential location for the corrosion attack.