To provide welding method capable of obtaining at high speed a welding bead structure that is high in welding strength as well as airtightness in a weld zone.
In a welding method in which edge welding or butt welding is performed using a laser beam, a weld zone 6 is irradiated with a YAG laser beam 11 along the extended direction of the weld zone and then with a semiconductor laser beam 13 in a manner following the YAG laser beam after a lapse of a specific interval L1. The width W2 of the semiconductor laser beam is set larger than the radius W1 of the YAG laser beam. Then, the weld bead structure 33 in which a heat conductive type wide bead 32 that is wider than the deep penetration bead is superposed on a keyhole-shaped deep penetration bead 31, is continuously formed along the extending direction of the weld zone 6.
Toshio Nakamura
Miyazaki Yoshio
Kaoru Onozuka
Next Patent: PIPE BENDER