| 摘要 |
PURPOSE:To enable the defectless and efficient welding of thick plates by melting base metals by a laser beam while controlling the focal length of a lens. CONSTITUTION:Root pass is executed by setting a focal position 10a at the point right under the groove of about 1/6 the plate thickness and melting the base metals 6, 7 in the 1st pass 9a. The left end of the end part is welded by setting the focal position 10b at the point right under the end part on the surface of the metal 6 and penetrating thoroughly the end part of the metal 6 in the 2nd pass 9b. The focal position 10c is set at the point right under the end part on the surface of the metal 7 and the end of the metal 7 is thoroughly penetrated to fuse thoroughly the lack of penetration part remaining in the 2nd pass 9b, in the 3rd pass 9c. The deflectless welding of the thick plates without the lack of penetration by the multi-layer laser welding is made possible by the above-mentioned method. The welding speed is increased and the welding efficiency is improved. |
