| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sufficient penetration depth with low output laser beam by forming the inner face of a metal cover to a sphere having its center at beam condensing point and gloss to increase utilization rate of laser beam. SOLUTION: A laser beam 1 is condensed to one point A, an object 2 to be welded is welded at the beam condensing point. The inner face 10a of a metal cover 10 surrounding part of the object 2 to be welded is formed to a sphere 11a having its center O at the beam condensing point A and gloss. The cover 10 is formed to a hemisphere bowl and a water pipe 12 is mounted with tightly adhering on its outer peripheral face. The cover 10 is cooled by cooling water flowing in the water pipe 12. The inner face of cover 10 can be formed to an ellipsoid. While the beam condensing point A is moved along the surface of object 2 to be welded, welding is executed. By this method, preheating or post heating can be executed simultaneously with welding by single operation. |
