| 摘要 |
PURPOSE:To prevent the disturbance of a welding arc by a magnetic field and to form an excellent weld zone in the stage of welding a pipe material circumferentially while rotating a welding torch by winding beflore hand a power feed cable which connects the welding torch and a welding head on the welding torch in the direction opposite from the rotating direction of the welding torch. CONSTITUTION:Pipe material 4, 4 made of an Al alloy or the like welded circumferentially with a welding torch 2 while the torch is rotated around the weld zone. An electric power supply cable 3 which connects a welding head 1 and a welding torch 2 is beforehand wound on the torch 2 in the direction opposite from the rotating direction thereof and an earth cable 6 connected to the material 4 is beforehand wound on the material 4 in the rotating direction of the torch 2 roughly in accordance with the number of windings of the cable 3. The direction of the induction field H1 by the eddy current of the cable 3 and the magnetic field H3 by the cable 6 are made mutually opposite and offset each other, thus only the magnetic field H2 by the current of the torch 2 remains and since the disturbance of the welding arc is obviated, the weld zone 5 having stable quality is formed. |
