| 摘要 |
PROBLEM TO BE SOLVED: To set effective quality criteria corresponding to various plate thicknesses, by adjusting the flaw detection sensitivity at the execution of ultrasonic flaw detection. SOLUTION: In the ultrasonic flaw detection method for detecting defects in a specimen by SH waves projected from a probe, the probe is operated and brought close to an edge face of the specimen or separated from it, while projecting an ultrasonic beam toward the face. The location at which edge echoes on the surface side reflected at the face and corner echoes to the back side reflected at the face are considered to be of the same degree of echo height is determined. The distance between the face and the probe at the location is taken as the distance of flaw detection, and echoes, reflected at the face of each specimen detected at the location, are set as flow detection sensitivity. Then by performing flaw detection on defects, the need for creating standard test blocks, each time the plate thickness and surface state of specimens differ from one another to simplify work can be eliminated and accurate evaluation can be made. COPYRIGHT: (C)2005,JPO&NCIPI
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