| 摘要 |
PURPOSE:To make possible satisfactory earthing without hindering a welding operation and to improve productivity by providing earth contactors which come into contact with the outside circumferential surface of a base metal consisting of a tubular body while allowing the rotation thereof and energizing the contactors by an energizing means so as to press the contactors to the base metal side. CONSTITUTION:The base metal 5 consisting of the tubular body is imposed to the upper part of a welding device 1 and a driving roller 14 contacts therewith to rotate the base metal. The base metal is thus welded. An earth device 7 for welding is constituted of the earth contactors 8 and the energizing means 10. The contactors 8 consist of plural carbon contactors 9 fused with copper and are energized by the energizing means to contact with the lower outside circumferential surface 5b of the base metal 5 so as to enclose the same. The surface contactability between the outside surface 5a of the base metal 5 and the contactors 9 is thus uniform and satisfactory and the earth function is provided while the rotation of the base metal 5 is permitted. The generation of the optimum arc is thus maintained.
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