| 摘要 |
PURPOSE:To obtain a sound welded joint without generating undercuts by heating the gouging surface generated after a keyhole so that the gouging surface disappears at a molten pool width decrease starting point behind a laser beam irradiation part. CONSTITUTION:When the gouging surface 2 remains at the position of the point where the width of a molten pool 3 starts to decrease, the undercuts are generated from an undercut generating mechanism and when the gouging surface 2 does not remain there, the undercuts are not generated. In addition, when the temperature difference between the gouging surface 2 and molten metal 3, namely, the molten pool is not too much, the molten metal 3 is moistened up on the gouging surface 2 which disappears. As a result, a postheating method by a TIG are is applied as a means to increase the whole temperature behind the molten pool 3 by heating the gouging surface 2. A weld zone of material 10 to be welded is irradiated with a laser beam 9 condensed by a lens 11 and simultaneously, the gouging surface 2 generated behind the irradiation part of the laser beam is irradiated with the TIG arc 12 to perform welding while postheating is carried out. |
