| 摘要 |
PROBLEM TO BE SOLVED: To provide a welded steel pipe having superior economic efficiency, by improving quality of a seam of the thick-walled welded steel pipe, particularly a temporarily welded part, and also by improving efficiency of tack welding, and to provide a method of manufacturing the same.SOLUTION: A method of manufacturing a welded steel pipe 7 is configured to mold a steel plate with both ends subjected to edge preparation into an open pipe, and to weld an edge preparation part of the open pipe while pressing thereof. An amount of upsetting by pressurization is set to 0.2-1.0 mm. After a butt surface 2 of a central part in the plate thickness direction of the edge preparation part and having a length of 10 mm or less in the plate thickness direction is joined by laser welding, both sides of a surface layer part in the plate thickness direction of the edge preparation part are joined by arc-welding. |
