Fretting Wear of Boundary Lubricated M50 Steel and Si3N4 Cylindrical Rollers on M50 Steel

Bench-level boundary-lubricated fretting experiments were conducted to compare the relative wear of all-steel and hybrid material pairs. Roller-on-raceway contacts were simulated using both AISI M50 steel and Si3N4 cylindrical rollers on flat AISI M50 steel disks. The rollers were 9 mm long with a 9 mm diameter. Tests were conducted with constant amplitude, oscillation frequency, and load. All tests were boundary-lubricated with 0.1 ml of DOD-PRF-85734, MIL-PRF-32538, MILPRF-23699, or unclassified ISO VG 68 aviation gear oil. Wear volume was calculated from 3D measurements on the roller and disk samples after each test. Wear tracks were inspected with light and scanning electron microscopy. It was concluded that hybrid pairs exhibited less wear than all-steel pairs when boundary-lubricated with three of the four aviation gear oils. Both hybrid and all-steel pairs exhibited similar wear when boundary-lubricated with MIL-PRF-23699 oil.