Abstract:To control the solidification process of metal, a new method, arc-ultrasonic, was developed. A high-frequency exciting supply was electromagnetically coupled with conventional welding supply. An arc-excited ultrasonic emission was induced successfully in arc combustion process. Some signals with different frequencies and currents were used in submerged arc welding and CO2gas-shielded arc welding. The effects of arc-ultrasonic on the structures and properties of
the weld (including the fusion zone, coarse grain zone and heat affected zone) were studied. The results show that more acicular ferrites form in the fusion zone, the toughness is improved under the arc-ultrasonic of different frequency, and the coarse microstructures in the partially melted zone is refined.

Key words: arc-ultrasonic; refined grain; fusion zone; coarse grain zone; heat affected zone