High-Cycle Fatigue Life and Strength Prediction for Medium-Carbon Bainitic Steels

High-cycle fatigue (HCF) behaviors of medium-carbon bainitic steels with various inclusion sizes and microstructural features were studied using the rotating–bending test. Here, different melting processes treated by three heat treatment routes incorporating bainite formation, namely bainite-based quenching plus partitioning (BQ&P), austempering (BAT) “disturbed austempering, DBAT”. The interior inclusion-induced crack initiation (IICI) noninclusion-induced (NIICI) modes found after failure. fracture surface IICI is characterized a “fish-eye” surrounding “fine granular area, FGA” in vicinity an inclusion. In contrast, microfacet, instead inclusion, at center FGA for NIICI surface. predications strength life performed on two based analysis. results showed that majority consumed within both failure modes. NIICI-fatigued samples can be conveniently predicted via parameters hardness sample size microfacet.