| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a lap laser welding method for galvanized steel sheets. SOLUTION: The lap laser welding method for the galvanized steel sheets 1 and 2 having decreased weld zone defects comprises preheating the superposed section of the galvanized steel sheets 1 and 2 by a preceding plasma heat source 7, then subjecting the steel sheets to normal welding by a succeeding laser beam 8 in succession thereto and adjusting the welding in such a manner that the plasma current (I) of the plasma heat source 7 satisfies 0.03×V×t1<I <0.08×V×t1 and the distance (L) between the centers of the plasma heat source 7 and the laser beam 8 satisfies L>125×I/V/t1, provided that I: the plasma current (A), V: a welding speed (mm/min), t1: the thickness (mm) of the galvanized steel sheet on the upper side, L: the distance (mm) between the centers of the plasma heat source and the laser beam.</p> |
