Abstract
A statistical analysis of ductile fracture surface was performed on JIS FCD400 spheroidal graphite cast iron with feritic matrix. Both the notched specimens with different notch acuity and the unnotched specimens were employed to obtain a wide range of stress triaxiality. All specimens were loaded to break under tensile loading at room temperature. The maximum nominal stress to break the specimen increased slightly with stress triaxiality, compared with structural steels. However, the extreme value probability of the maximum dimple size in a given unit area showed a clear dependence on the maximum nominal stress. In addition, the lateral growth factor of the maximum dimple against the graphite size increased due to an increased level of transverse stress with stress triaxiality. Thus, the extreme value analysis of the maximum dimple size and the lateral growth factor of the maximum dimple should be expected for providing a positive and quantitative information regarding the fracture behavior of the ductile cast iron.
