ULTRASONIC FLAW DETECTION METHOD, ULTRASONIC FLAW DETECTING DEVICE, AND PRODUCTION METHOD FOR SEAM-WELDED PIPE

摘要

PPROBLEM TO BE SOLVED: To provide an ultrasonic flaw detection method and an ultrasonic flaw detection device for seam-welded pipes can ultrasonic-detect flaws with high accuracy in welding seam portion of seam-welded pipes. PSOLUTION: A welding seam position of a seam-welded pipe 1 is detected, based on an image signal output from an infrared camera 5 to image a welding seam portion 1a of the seam-welded pipe 1; a probe displacement distance is calculated from the detected welding seam position, and the welding seam portion 1a is ultrasonically flaw-detected by moving ultrasonic probes 3a, 3b, in the circumferential direction of the seam-welded pipe 1, based on the calculated displacement distance, in which the welded pipe having flaws at the welding seam portion is used; the welding seam position of the seam-welded pipe is detected from an infrared image obtained by the infrared camera 5; defects are ultrasonically detected by an ultrasonic flaw detector 3; the welding seam position is detected from the defect signal; and the probe displacement distance is compensated based on the difference of the two detected welding seam positions. PCOPYRIGHT: (C)2010,JPO&INPIT