Abstract
In this study, rotating bending fatigue tests were carried out using cylindrical specimens of spheroidal graphite cast iron(FCD400) and flaky graphite cast iron(FC250) and fatigue limits of these cast irons were estimated by the √<area> parameter model. Fracture started at microshrinkages that exist on the neighboring surface in both materials. These defects were equivalent of a small blind hole. The size of the defect was 100〜140 μm in FCD400 and 50〜100 μm in FC250. The estimated value of fatigue limit gave a good approximation in FCD400. On the other hand, the estimated value in FC250 was remarkably large, the √<area> parameter model was not applied.
