| 摘要 |
PURPOSE:To perform perfect welding that does not cause cracking in good working environment by making preheating and welding providing beam irradiation end for preheating and beam irradiation end for welding in parallel. CONSTITUTION:A weld zone 9 of materials 8a, 8b to be welded is placed right below the center of a working head 16 of beam irradiation end B for preheating. Then, beam irradiation end A for welding is raised by a lifting device until the center of a hole 13 of a tube 5 coincides with the center axis of a tube 1. When a laser beam is generated, the laser beam goes straight, condensed by a condenser lens 17, and irradiated from the tip of a working head 16 onto the weld zone 9. At this time, as the distance between the tip of the working head 16 and weld zone 9 is set longer than focal length, energy density is low and only heating is made. Then, the weld zone 9 of the material to be welded is shifted to the left and placed right under the working head 4 of beam irradiation end A for welding. Then, it is lowered until the center of a hole 11 of a tube 5 at beam irradiation end A for welding coincides with the horizontal center axis of the tube 1, and the laser beam is irradiated onto the weld zone 9. Thus, welding is performed by a beam of high energy density. |
