Micromechanism
of cumulative damage in
bearing steels under Rolling Contact Fatigue
Yachao Sun, Hongrui Cao*
State
Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong
University, Xi’an 710049, PR China
*Corresponding author.
E-mail address:
chr@mail.xjtu.edu.cn
(H. Cao).
Abstract:Rolling
Contact Fatigue (RCF) is harmful and inevitable to bearings and usually
results in the initiation of subsurface damage.
This
paper focuses on the cumulative mechanism of subsurface damage in
bearing steels arose from cementite during RCF. The distribution of
subsurface shear stress in bearings was investigated by finite element
simulations. A two-phase atomic model of bcc-Fe and cementite was built.
Ten alternating shear load cycles were applied when the model was
initially in the elastic, elastic-plastic and plastic stages,
respectively. The results show that cyclic softening diversely occurs in
all three types of stress responses, and the progress of plastic
accumulation depends on the amplitude of cyclic load and cycles.
Severe
shear deformation eventually leads to the damage of the cementite phase,
which might be the microscopic mechanism of the fatigue failure of
bearing steels. The conclusions presented have general applicability to
brittle inclusions in bearing steels.
Keywords: Bearing steels, Cyclic deformation, Cumulative
fatigue damage, Micromechanism