| 摘要 |
PURPOSE:To increase efficiency of utilization of laser beam energy and perform more uniform welding of high quality, by heating the back side of the weld zone in carrying out welding supplying plasma forming gas to the vicinity of weld zone and melting added metal. CONSTITUTION:The focal point of a laser beam irradiator 1 is placed near the surface of material 2 to be welded, and specified quantity of He gas is supplied toward the point of incidence of laser beam to the base metal 2 through a gas flow passage 4. Consequently, plasma atmosphere is formed near the weld zone, and the beam 3 is projected upon the weld zone through the atmosphere. An added metal wire 6 is fed through a guide 8, and the tip is molten by heat of plasma atmosphere before it arrives at the beam 3, and shifted to the upper part of butted end faces of welding to form a bridge. This is heated and kept hot by plasma atmosphere and mixes with molten metal of welded end faces. At this time, a welding torch 11 is arc energized and forms plasma on back side of the weld zone, and heats and keeps hot the back side. |
