| 摘要 |
PROBLEM TO BE SOLVED: To provide means for assisting an electroseamed steel pipe to identify a seam part without deteriorating flaw detection accuracy of ultrasonic flaw detection of a whole cross section of the seam part with MP-UT and without causing excessive interference between a cutting tool used for inner surface bead cutting and a pipe inner surface.SOLUTION: In an electroseamed steel pipe having a seam part 5 being a junction by electric resistance welding 3, recesses 15 arranged in parallel in a plurality on two virtual parallel lines 13 holding the seam part 5 therebetween on the pipe outer surface side are formed in both seam side parts 12. |
