| 摘要 |
PURPOSE:To prevent the depression of the penetration weld bead in an overhead position in an arc welding method therein an arc is oscillated while control for copying a groove is performed by applying pulsatively gas to the arc when the arc comes to the central position of the detected groove. CONSTITUTION:When a torch 4 with an electrode 3 positioned in the groove 2 of base metal 1, 1' facing each other is oscillated in the transverse (right and left in the figure) direction in the groove 2, a change in the space between the electrode 3 and the materials 1, 1' is detected as a voltage signal, etc. When the torch 4 is positioned at the center of oscillation, a signal is applied to a signal generator 26, and the oscillation of the torch 4 is stopped by the output from the generator 26 during the set time; at the same time, the welding current changes to a high value. The output from the generator 26 opens a solenoid valve 33 to eject pulsatively the inert gas from a cylinder 34 through a piping 35 from the circumference of the electrode 3 of the torch 4, thereby shrinking the arc and increasing the effect of digging. |
