抄録
The reasons for inconsistent fatigue limit in ductile cast iron were studied from the viewpoint of differences in defect size. Rotating bending fatigue test was performed on three kinds of austemperd ductile cast iron (ADI) specimens with different levels extracted from the same ingot. As a result. the conservative (safe) fatigue limit could be estimated by using both the maximum defect size evaluated with extreme statistics and the equation proposed by Murakami et al. Moreover, by using defect size and fatigue life obtained from the high stress amplitude fatigue test, it was clarified that the S-N curves of ADI could be estimated more quickly than the normal fatigue test.
