| 摘要 |
PURPOSE:To prevent a failure in welding due to a failure in positioning by giving a mark to an upper steel plate when the upper plate between two thin steel plates superposed one over another has larger area, and carrying out arc spot welding between those two thin steel plates on the basis of the mark. CONSTITUTION:In welding two thin steel plates 5 and 6 together, if the upper plate 5 has larger area than the lower plate 6, for example, when the floor pan of a motorcar is welded to the floor under reinforcement, a hole 7 is bored in the thin steel plate 5 having larger are previously. On the basis of the hole 7 as a mark, arc spot welding 8 is carried out. The arc spot welding may be carried out at the hole 7 and a position at specific distance from the hole 7. Further, the shape of the hole 7 is not specified and a projecting part, recessed part, step, notch, etc., are used as the mark in addition to the hole 7. |
