| 摘要 |
PURPOSE:To reduce working time and to improve groove accuracy by sticking tentative assembling jigs to the end parts of steel pipes to be joined, and mating and centering the pipes. CONSTITUTION:A pair of halved backing strips 3, 3' are tack-welded by spot welding to the outside circumferential edges at the ends of steel pipes 1, 2 to be joined. Tentative assembling fittings 4, 5 of an L-shaped section are fixed to the end parts of the strips 3, 3' in the circumferential direction of the respective pipes. Then, the pipe 2 on the movable side is fitted to the pipe 1 on the stationary side and the pipe is moved downward and is kept moved downward until the fittings 4, 5 fit to each other. Indicating lines are beforehand put by scribing on the fittings 4, 5, and the strips 3, 3' on the side facing said lines are mated. At the same time, the end faces of the pipes are alinged along the centerline of the strips 3, 3' and are finely adjusted so as to form a necessary root gap, whereby the centering work is completed. The strips 3, 3' and the end parts of the pipes 1, 2 are tack-welded by spot welding at plural points, and the fittings 4, 5 are removed. |
