Effect of the hardness of hardened steels and the action of oxides on fretting wear

The influence of hardness on fretting wear was investigated experimentally in air using a bearing-steel ball sliding on a 0.6% C steel plate under a load of 34.3 N at a frequency of 16.6 Hz. The total number of cycles was 10⁵ and peak-to-peak amplitudes of 45 and 260 μm were used. The hardness of both materials was varied from 220 to 850 HV.Hardness had only a minor influence on fretting wear. The significant factor was the action of any black oxide produced. The black oxide reduced the wear of the surface from which it was generated but acted as an abrasive against the opposing surface. At a sliding amplitude of 260 μm there were discontinuities on the wear curves due to the formation of black oxide. Similar wear characteristics were obtained with an amplitude of 45 μm except that some heavy damage due to adhesion and material transfer occurred.