Stabilization of High-Current Buried-Arc Welding Using Large Diameter φ1.6mm Wire by Low-Frequency Modulated Voltage Control

Abstract

The authors focused on a buried-arc phenomenon for a high-efficiency thick-plate welding and developed a “low-frequency modulated voltage control” in order to stabilize a buried arc at high-current range, which repeats high and low voltage terms using a welding power source with constant-voltage characteristic. When the control was applied to high-current buried-arc welding using solid wires of φ1.2mm and φ1.4mm, a rotating transfer mode was observed at a high-voltage term. It was clarified that a high-current buried-arc phenomenon was stabilized by supporting the buried space with a rotating arc. On the other hand, when the low-frequency modulated voltage control was applied to a solid wire of φ1.6mm, it was revealed that a rotating transfer mode was not observed although the control was effective in stabilizing a high-current buried-arc phenomenon. Our study shows its stabilization mechanism based on the experimental observation of the difference in arc phenomena during a buried-arc welding with and without low-frequency modulated voltage control, in this paper. Applying this result, we additionally report a high-efficiency thick-plate welding with a low wire feed rate condition.