Granular bright fact crack propagating under very high cycle fatigue

Abstract

The different crack initiation modes from different internal defects of a high carbon chromium bearing steel are investigated in the present paper. The relative granular bright facet (GBF) size is approximately proportional to . The critical applied stress intensity factor range at the periphery of inclusion ΔK_inc,th, above which the GBF will no longer be formed, was obtained. For the present SUJ2 steel, ΔK_inc,th = 8 MPa m^1/2. The crack growth process in GBF is further investigated by the low–high two-step variable amplitude loading tests. The crack growth process in GBF can be described by . The exponent m₀ is a material constant independent of the applied stress amplitude and the inclusion size and increases with increasing of HV.

Keywords:

• Bearing steel
• Very high cycle fatigue
• Stress intensity factor
• GBF
• Crack growth

Acknowledgements

The present work was financially supported by the National Natural Science Foundation of China (grant no. 51101094) and Science and Technology Project of Hebei Province (grant no. 13211035).