SBF試験法によるSUS316鋼の疲労損傷評価の検討

抄録

A new fatigue testing technique, the small bulge fatigue (SBF) test using a small disk-type specimen (8 mm in diameter) with flat and concave surfaces has been recently developed by the authors’ group. In this study, Type 316 austenitic stainless steel was subjected to the pressurized disc fatigue (PDF) test using a large disk-type specimen (87 mm in diameter), and the tests were stopped at several stages of the fatigue life for preparing some interrupted test specimens with the various degrees of fatigue damage. The SBF test specimens were taken from the surfaces of PDF test specimens to examine the adaptability of this technique to fatigue damage assessment. The experimental results showed that the fatigue life of SBF specimen, which included cracks formed by the PDF test, decreased significantly compared with the specimen with no crack and the undamaged. It was noteworthy that some small cracks introduced by the PDF test were opened being clearly visible by the SBF test, although they were closed and invisible just after the PDF test.