Fretting fatigue behavior of steel wires contact interface under different crossing angles

Fretting fatigue tests on steel wires were conducted on self-made fretting fatigue test equipment. Fretting fatigue behavior and the influence of crossing angles on this behavior are studied by analyzing the F-t-D-N curve. The results show that contact load increases as total wear volume and the friction coefficient of steel wire decrease with the crossing angle of 18 degrees in the mixed and partial slip regimes. In the slip regime, both variables increase. When the strain ratios decrease, fretting amplitude increases and the fretting regime shifts from the partial slip one to the mixed and slip regimes, the total wear volume, friction coefficient, and friction surface area of the loaded steel wire all increase, whereas the contact load in the fretting area of this wire decreases. Lower contact load, total wear volume and friction coefficient and longer fretting fatigue life were induced by the crossing angle of 18 degrees than when this angle is 90 degrees. Few wear particles and furrows are observed in the three fretting regimes of the wearing surface. The main wear mechanisms are adhesive and fatigue wear. However, more obvious wear particles and furrows can be observed with the crossing angle of 90 degrees.