Fatigue limit estimation for carburized steels with surface compressive residual stress considering residual stress relaxation

The mechanism of residual stress relaxation for carburized steels was elucidated and their fatigue limit was estimated. The compressive residual stress in the carburized steel after rotating bending fatigue tests is mainly influenced by the relaxation during the compressive loading phase, although it increases at the early stage. The fatigue limit of carburized steels can be estimated according to the modified Goodman diagram considering the residual stress relaxation. The proposed equation shows the maximum value of the fatigue limit (1013 MPa) of carburized steel and the maximum value of the compressive residual stress contributing to the increased fatigue limit.

Automated summary

The mechanism of residual stress relaxation in carburized steels was studied, and the fatigue limit was estimated. The compressive residual stress in carburized steel after rotating bending fatigue tests is mainly affected by relaxation during the compressive loading phase, despite an initial increase. The fatigue limit of carburized steels can be estimated using the modified Goodman diagram, considering the relaxation of residual stress. The proposed equation reveals the maximum value of the fatigue limit (1013 MPa) for carburized steel and the maximum value of the compressive residual stress contributing to the increased fatigue limit.