| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a laser-welded steel pipe stably in a high yield by highly and precisely determining a laser welding situation and by changing a welding condition on the basis of the determined result. <P>SOLUTION: The irradiating region of a laser beam irradiated from an outer face side at an edge portion is monitored from the inner face side of an open pipe. When a key hole penetrating to the inner face side of the open pipe is observed, the welding condition of the laser beam is continuously kept. When the keyhole penetrating to the inner face side of the open pipe is not observed, the welding condition of the laser beam is changed. Thus, the welding operation is performed while the keyhole penetrating through the open pipe from the outer face side to the inner face side is formed in the irradiating region of the laser beam. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
