| 摘要 |
PROBLEM TO BE SOLVED: To perform the welding of excellent quality free from generation of defects such as blow hole and pit by arranging a transparent plate at a base end of a nozzle body, and radiating the laser beam on a part to be welded before the nozzle body. SOLUTION: A tip part 7b of a nozzle body 7 has a cylindrical body shape whose inner side is of conical shape which is tapered to the end, and the inner side of a front end part forms a step of large inner diameter. A funnel-shaped side nozzle 6a is coaxially fitted to the front end part of the stepped part. A transparent plate made of protective glass is put on a base end surface (h) of a base part 7a of the nozzle body 7, and a part to be welded before the side nozzle 6a is irradiated with the laser beam coaxially through the transparent plate. The shield gas from a second gas feed pipe 3 is uniformly distributed in the circumferential direction by a groove (e), and ejected from a clearance (f) in an air-curtain shape in the radial direction. The transparent plate is cooled by the shield gas to prevent sticking of the spatter from an irradiation part. |
