Weld seam detection method and apparatus for electric resistance welded steel pipe

摘要

PROBLEM TO BE SOLVED: To provide a method and device for improving seam follow-up accuracy of a probe by accurately detecting the position of a weld seam part at a flaw detection position of an ultrasonic flaw detection device.SOLUTION: A method for detecting a weld seam part of an electroseamed steel pipe, comprises the steps of: measuring the temperature distribution of a weld part of an electroseamed steel pipe 1 at the upstream side of an ultrasonic flaw detection device 8; detecting the weld seam part 11 and a weld bead cut part of the electroseamed steel pipe from the temperature distribution of the weld part to specify the positional relation between the weld seam part 11 and the weld bead cut part; imaging the weld part whose temperature distribution is measured at a flaw detection position of the ultrasonic flaw detection device on the downstream side; specifying the position of the weld bead cut part from the captured image; and calculating the position of the weld seam part 11 from the position of the weld bead cut part on the basis of the positional relation between the weld seam part 11 and the weld bead cut part.