| 摘要 |
PURPOSE:To increase the effective absorptivity of laser beams by welding surfaces and to perform surely seam welding of thin steel sheets by fixing the butt part of steel sheets to cavities to shield said part and focusing the laser beams by multiple reflections. CONSTITUTION:The end faces of thin steel sheets 1, 1' are butted and the upper and lower parts near the weld line thereof are shielded by cavities 4T, 4B and are fixed by fixing parts 42T, 42T', 42B, 42B'. The step in the butt part is decreased by such fixing by which the deformation by thermal strain is prevented and the butt surfaces is uniformly held. Laser beams 3, 3' are introduced and the energy reflected and radiated from the weld point are focused to the weld point by multiple reflections in the cavities 4T, 4B. The heat is diffused near the weld zone by limiting the weld section in such a way by which the stable seam welding is accomplished. |
