| 摘要 |
PURPOSE:To obtain an initial boxing part having no undercut, by placing a torch at a position separated from an end face of a substance to be welded, by a prescribed distance, turning on an arc under a lower welding condition than a regular condition for a prescribed time, and after that, executing regular welding. CONSTITUTION:At a position separated by a distance G to the outside in the direction of a weld line (l) from an end face la of a substance to be welded 1, torches 2, 2 are opposed and placed so as to be thrust into the plate thickness direction by a distance R. Under a welding condition which is lower than regular welding current and voltage, an arc is turned on for a prescribed time. Subsequently, the torches 2, 2 are moved back to a regular position at a speed equal to a regular welding speed. After that, gradually raising the welding condition, fillet weld is executed under the regular welding condition and at the regular welding speed. In this way, concentration of welding heat to the edge part is prevented, and an initial boxing part which leaves no recessed part nor unwelded part, and generates no undercut is obtained. |
