| 摘要 |
PROBLEM TO BE SOLVED: To conduct ultrasonic flaw detection without contact with a pipe to be inspected, such as a steel pipe with high precision. SOLUTION: A transmission ultrasonic probe 18 and a reception ultrasonic probe 20 are arranged with a space on the surroundings of a pipe 14 to be inspected, and the inclination direction of the transmission ultrasonic probe 18 to the normal of the external surface 14a of the pipe 14 with an incident angleθ1 and the inclination direction of the reception ultrasonic probe 20 to the normal of the external surface 14a are reversed each other. With this arrangement, ultrasonic pulses b output from the transmission ultrasonic probe 18 are propagated in the pipe 14 in the propagation mode of guide waves. The attitude of the reception ultrasonic probe 20 to the external surface is set so that a defect echo d can be detected which propagates in the reverse direction to the ultrasonic pulse b in the propagation mode of guide waves when this ultrasonic pulse contacts a defect 42 an ultrasonic pulse b is produced. COPYRIGHT: (C)2010,JPO&INPIT
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