| 摘要 |
PURPOSE:To perform the captioned welding at high efficiency and at low cost without doing the conventional intermediate annealing process and grinder work, by welding the root face part of the groove with lasers and then welding the face and back side by the known method. CONSTITUTION:The butt parts of thick base metals A and B are machined to H- shape (or X-shape or K-shape), and the root face is processed to 1-3mm. The root face parts A1 and B1 are joined butt to butt, and the groove surface is preheated, then the parts are welded with lasers. After this laser welding, the back run and face run are performed by the known method. Since the welding of the root face part has been finished, back droop is not caused by the back run in the groove deep part of the face side, and the subsequent gouging process is not needed, and intermediate annealing and grinder process are not necessary, so that the face run may be started immediately after the back run. Thus, the welding efficiency may be greatly increased. Besides, heat treatment facility is not needed, and the running cost and maintenance expenses may be saved. |
