| 摘要 |
PURPOSE:To considerably improve the reliability of weld zones by inserting a heat exchanger tube into a tube hole in close contact therewith, and securing the same by laser beams from the inner side of the heat exchanger tube, in a feed water heater. CONSTITUTION:First, a heat exchanger tube 6 is inserted into the tube hole pierced in the prescribed position of a tube plate 5, and the tube 6 is put in close contact with the tube hole by expanding the same. Thence, a plane mirror 8 mounted to a laser welding device 9 is inserted into the tube 6, and the plane mirror is so adjusted that the laser beam emitted from the device 9 falls onto the inside surface of the tube 6 at a right angle thereto. The tube 6 and the plate 5 are subjected to welding by as much as required number, thereby forming weld zones A. Since in this way the laser welding is executed without the aid of manual labor, the reliability of the weld zones A is considerably improved. |
