| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for obtaining a weld zone of high quality without deteriorating welding efficiency, and further, stably producing a laser-welded steel pipe at a high yield. <P>SOLUTION: In the method for producing the laser-welded steel pipe in which a steel sheet is formed into a cylindrical open pipe by forming rolls, laser beams are emitted from the outer face side of the open pipe while pressurizing the edge parts of the open pipe by squeeze rolls, and the edge parts are laser-welded, the laser welding is performed in such a manner that two laser beams with a diameter of <0.4 mm in a spot size in a just focus are emitted to the right side and the left side of the edge parts, respectively, an interval between the central points on the surface of the steel sheet of the right laser beam emitted to the right side and the left laser beam emitted to the left side is controlled to ≥0.4 mm, and also, the right laser beam and the left laser beam are arranged not to be superimposed on each other in the back face of the steel sheet. <P>COPYRIGHT: (C)2013,JPO&INPIT |
