Ultrasonic testing is difficult for cast stainless steel which is used as the material of main coolant pipes in pressurized water reactors, because of the large attenuation and scattering of ultrasonic waves caused by its macro structure. Ultrasonic testing for the axial fatigue crack on welding area in the test piece of the cast stainless pipe was performed, using the double large aperture ultrasonic probes. In this study, depth sizing of defects was performed under the positive result of the detection of defects in former study. As a result, sizing of defects with over 20mm target depth for the specimen thickness 69mm is highly possible.%加圧水型軽水炉の1次冷却材管等に使用されている铸造ステンレス鋼は，その結晶構造により超音波の減衰や散乱が大きいため，超音波探傷試験は困難であるとされている.INSSでは，大口径集束2振動子探触子を用いた自動超音波探傷法を，铸造ステンレス鋼中の溶接線を横切る疲労き裂の探傷に適用し，欠陥の検出性が良好であることを確認してきたが，本研究では欠陥の深さサイジング性について検証した.板厚69mmに対して約20mm以上の疲労き裂は，深さサイジングの可能性が高い.
展开▼
