| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress the generation of a blow hall and prevent the deterioration of the strength of a welded zone. SOLUTION: A lap joint welding is performed by making a work W, which consists of a lapped galvanized steel plate and a conventional steel plate, is irradiated with a laser beam 9 emitted from a laser beam machining head 7. A pressurizing pin 11 provided on the laser beam machining head 7 is pressurized against the work W by an air cylinder 17 via the laser beam machining head 7. At the beginning of the welding work, an electromagnetic valve 35 is switched in a way that air is supplied to a pressure regulator 31 on high- pressure side, the work W is pressurized at high pressure, and a joint gap is decreased, thus the generation of an undercut is prevented. After the welding work has been begun, the electromagnetic valve 35 is switched in a way that air is supplied to a pressure regulator 33 on low-pressure side, the work is pressurized at low pressure, the joint gap is increased, and gaseous zinc generated during the welding is released out through the broadened gap, thus the generation of a blow hole is prevented.</p> |
