Predicting Wear for Metal Surfaces in Sliding Contact Using a Low-Cycle Fatigue Wear Model

The frictional force when a hard surface slides over a relatively soft one is explained as the force needed to push waves of plastically deformed material along the soft surface ahead of asperities on the hard one. Using plastic strain increments determined from the wave model and assuming that wear occurs as a result of low-cycle fatigue, predictions are made of wear which take account of the surface roughness and lubrication conditions and a comparison is made with experimental results. Metallographic results are given which support the assumption that low cycle fatigue is important in causing surface damage and hence wear. These results also show that ironing of the surface by the passage of waves leads to surface damage and wear. It is concluded that in future work account will have to be taken of both low-cycle fatigue and ironing in making wear predictions.