| 摘要 |
PURPOSE:To perform continuously multicircumferential welding without erasing an arc by reversing the moving direction of a welding carriage, which can feed a filler wire from two directions, front and rear, in the weld line direction, so as to overrun upon every one full circumferential welding. CONSTITUTION:A welding carriage 2 is run while regular welding is performed. The carriage is moved forward in a clockwise direction and the movement is continued until an electrode 4 arrives at a point S. Current supply, arc voltage control, vertical position adjustment of a wire and carriage traveling are maintained even after the arrival at the point S and only the wire feed speed is gradually decreased. The current is decreased with slight delay from the decrease in the wire feed speed and the decreasing state is continued even after the feeding of the wire is stopped. The wire is retreated by a prescribed distance in synchronization with the decrease of the current to the arc holding current. The carriage 2 is stopped where it overruns by a required distance, then the carriage is moved backward. The carriage 2 is again stopped where the electrode 4 coincides with the start point S and the current to the electrode is increased up to the initial current. The wire is fed from the 2nd feeder 3' in the backward movement. |
