Multiaxial plain and notch fatigue strength of thick-walled ductile cast iron EN-GJS-600-3: Combining multiaxial fatigue criteria, theory of critical distances, and defect sensitivity

Multiaxial fatigue tests were carried out on plain and notched specimens extracted from EN-GJS-600-3 pearlitic DCI heavy-section castings. Two notches of different severities were combined for the determination of mode I and mode III critical distances, along with the related intrinsic fatigue strengths. SEM and CT clearly showed that fatigue cracks initiated from graphite nodules and shrinkage pores in notched and plain specimens, respectively. Different multiaxial criteria were compared, and best predictions were obtained with the Carpinteri et al. criterion with four parameters: axial and torsional intrinsic fatigue strengths, combined with the two different related critical distances.