| 摘要 |
PURPOSE: To form an excellent weld zone free from blow holes or weld metal solidification cracks by increasing the molten pool both in width and length so that the molten flow formed by the preceding keyhole may be blocked by the succeeding keyhole to make the peripheral flow, and promoting the removal of bubbles therefrom. CONSTITUTION: A first laser beam B1 to form a keyhole H1 through a base metal 7 and a second laser beam B2 to form a keyhole H2 of the depth of at least 30% that of the base metal 7 are continuously arranged in the welding direction and at the position where these laser beams are separated from each other so that the keyholes H1, H2 are not overlapped each other. The welding is achieved while irradiating the second laser beam B2 in the molten pool 4 formed by the first laser beam, and the upper reinforcement 6 is formed on the weld zone to collect the bubbles 3 present in the molten pool 4. |
