Fretting Wear Behavior of Steel Wire and the Effect of Fretting on Its Fatigue Fracture Behavior

A series of fretting wear tests were carried out to investigate the fretting friction and wear behavior of steel wires and the effect of the fretting on the fatigue fracture behavior of the wires. Thus the effect of the fretting wear test duration and normal load on the fretting wear behavior of the steel wire was examined, the effect of the fretting on the fatigue fracture of the fretted steel wire was also explored on a servo-fatigue test machine. Moreover, the morphologies of the fretted steel wires surfaces and of the fatigue-fractured fretted steel wire were observed on a scanning electron microscope. The friction coefficient and wear depth of the steel wires were measured and taken as the characterization parameter to describe the fretting wear behavior in relation to the fretting duration and contact loads. It was found that the friction coefficient varied within a narrow range at various fretting conditions and the fretted wear scar depth of the steel wires increased with increasing fretting duration and contact load. The fatigue life of the fretted steel wires was inversely proportional to the wear scar depth. In addition, the fretting conditions had a significant effect on the shape and size of the wear debris. And the fretting wear mechanisms of the steel wires were also dependent on the fretting conditions. Namely, the steel wire fretted at a larger load or shorter fretting duration was dominated by adhesion, while that at a smaller load or extended fretting duration was dominated by fatigue and peeling off.