The Research On Friction And Wear Characteristics Of GCr15/45# Steel Under Oil Lubrication

In this paper, the friction and wear characteristics of GCr15/45# steels were studied under dry friction, gear oil lubrication, engine oil lubrication and hydraulic oil lubrication. And the effects of different frequency and different loads on friction and wear characteristics of GCr15/45# steels were investigated under gear oil lubrication.A series of tests were carried out on the DELTALAB-NENE DS20 tester under dry friction and different oil lubrication conditions, with the friction pairs contacted by ball-plane mode. The friction coefficient and wear mechanism are compared under dry friction and lubrication conditions at the frequency of 1Hz and the load of 200N. The effects of different frequency and different loads on friction and wear characteristics of GCrl5/45# steels were investigated under gear oil lubrication at the frequency of 0.5Hz, 1Hz,2Hz and 5Hz and the loads of 100N and 200N. Analyses of 45# steel's worn surfaces and wear debris were carried out by optical microscope, scanning electron microscope (SEM) and EDX.Main conclusions are drawn as follows:(1) The coefficient under dry friction is larger than that under oil lubrication conditions in stable period, and the worn surface under dry friction is severer than that under oil lubrication conditions.(2) The main wear mechanism under dry friction is adhesive wear and fatigue wear, and the main wear mechanism under oil lubrication conditions is fatigue wear.(3) The friction coefficient and wear behavior are affected a lot by oil viscosity. Gear oil whose viscosity is the highest leads the smallest friction coefficient and the most lightest worn surface. On the contrary, hydraulic oil whose viscosity is the lowest leads the largest friction coefficient and the severest worn surface. (4) The friction coefficient and wear behavior are affected obviously by frequency and loads. In a certain range, the friction coefficient and the area of wear scars have a tendency of decreasing with the increasing of frequency. And the friction coefficient has a tendency of decreasing with the increasing of load, while the area of wear scars gets larger.