Investigation on the fretting fatigue behaviors of steel wires under different strain ratios

The fretting fatigue tests of steel wires were performed on the self-made fretting fatigue test equipment under different strain ratios ranging from 0.90 to 0.70 with contact loads of 50 N and 70 N. Curves of Ft–D–N were drawn, and the dissipated energy was calculated through the curves of Ft–D. Morphological features of fretting scar and fracture surface were observed by scanning electron microscopy (SEM). The results reveal that as the strain ratio decreased, the fretting regime changed from partial slip regime to mixed regime and slip regime. Shorter fretting fatigue life, higher wear coefficient were induced by a lower strain ratio. The curves of dissipated energy corresponding to three kinds of fretting regimes were different from each other. Morphologies of adhesive wear, abrasive wear and fatigue wear as well as accumulation of plastic deformation and micro-cracks were observed in fretting scars. All fatigue fractures in different fretting regimes could be divided into three regions.