| 摘要 |
PURPOSE:To make the hardness of a weld metal lower and the toughness thereof higher and to decrease thermal strain in the stage of welding a member to be welded by a laser beam by branching part of the laser beam and irradiating the weld metal with the out-of-focus laser beam. CONSTITUTION:The laser beam 1 is converged by a condenser lens 4 and is focused to the weld zone of the base metal 9 to be welded so that the base metal is welded by the weld metal 8. Part of the laser beam 1 is taken out by a beam splitter 2 and is reflected toward the metal 9 by a bent mirror 3 facing the splitter. Such beam is passed through a condenser lens 5 to deviate the focus so that a suitable irradiation area and power density are obtd. Such beam is irradiated to the weld metal 8 to heat the weld metal to the temp. just below the A1 transformation point thereof then to temper the same. The weld metal is continuously tempered in succession to welding, by which the hardness of the weld metal 8 is decreased and the toughness thereof is improved with the simple operation. The productivity is thus improved. |
