| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a welded steel pipe which has no weld defects in the seam, and to provide a method of efficiently manufacturing the welded steel pipe. <P>SOLUTION: In the method: a steel strip 1 is formed into a cylindrical shape so that both end parts 1a, 1b of the steel strip are opposed to each other while continuously conveying the steel strip 1; the seam is formed by joining both end parts after melting the end parts on both sides over the full thickness by emitting a high-density energy beam 10 onto the end parts on both sides while pressurizing both the end parts with squeezing rolls 4a, 4b; the projecting parts of the seam on the outside surface side and the inside surface side of an obtained welded steel pipe are removed by cutting work; next, a repaired seam part which is solidified after remelting the depth of ≥0.5 mm from the surface and over the width of two or more times as large as the seam is formed on the inside surface side and also the center line 8 of the seam and the center line of the repaired seam part are matched. <P>COPYRIGHT: (C)2010,JPO&INPIT |
