| 摘要 |
PROBLEM TO BE SOLVED: To reduce the welding defects such as the appearance of inclusions of a base stock to the inner/outer surfaces of a steel tube and a penetrator. SOLUTION: In the manufacture of a welded steel tube, in which a steel strip is cylindrically formed so that the ends of both sides of the strip are opposed to each other while the strip is continuously transported, and in which a joined part is formed for bead grinding by melting the abutting part at the end of the strip and upsetting it, the joined part is melted over the entire thickness by irradiating it after the bead grinding with a high energy beam while the joined part is restrained in the circumferential direction. |
