Rolling contact fatigue property and failure mechanism of carburized 30CrSiMoVM steel at elevated temperature

• A high temperature significantly reduced the RCF life of carburized 30CrSiMoVM steel.
• RCF crack was driven by asperity contact rather than by distribution of shear stress.
• Decrease of RCF life was caused by variation of lubrication status from ML to BL.
• Pitting and delamination were two main failure modes of carburized layer.
• The formation of the synergistic tribofilm caused failure mode changing.

Rolling contact fatigue (RCF) behavior of carburized 30CrSiMoVM steel was experimentally investigated at elevated temperature. The results show that RCF crack was drive by asperity contact rather than the orthogonal shear stress or the maximum shear stress. The value of L10, L50, La life at 100 °C decreased by 48.3%, 44.1%, 43.2%, respectively, compared with that at 40 °C, which was attributed to lubrication status changing from mixed lubrication regime to boundary lubrication regime. The formation of the synergistic tribofilm containing Fe2O3, FeS, ZnS, FePO4 and Ca3(PO4)2 around the center of the contact area effectively prevented initiation and propagation of RCF crack under boundary lubrication status, resulting in the obvious variation of the failure mode of the carburized layer.