| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to improve detecting accuracy and to reduce operating man-hours by a method wherein a means by which a scanner body is moved intermittently at a first pitch to the length direction of an inspection range is provided and a means by which the scanner body is moved intermittently at a second pitch to a direction at right angles to the direction is provided. SOLUTION: A first movement part 13 and a second movement part 14 intermittently move a scanner body 10 at a first pitch and at a second pitch to the length direction of a welding bead 3 and to a direction at right angles to the direction, and probes 15A, 15B for sound-velocity measurement detect the transmitted sound velocity of a pipe 2. As the first pitch and the second pitch, a pitch for high-speed flaw detection and a pitch for accurate flaw detection can be set. A probe 11A for flaw detection and a probe 11B for flaw detection make ultrasonic waves incident on the pipe 2, and they detect ultrasonic reflected echoes which are reflected by their discontinuous parts. The probes 11A, 11B for flaw detection are moved zigzag owing to their structure, and they perform an ultrasonic flaw detecting operation in the temporary stop position of the scanner body 10 so as to inspect a defect. By this method, a man-hour can be reduced, and the inspection accuracy of a scanner can be enhanced. |
