Composition Optimization of Solid Friction Modifier and the Wheel/Rail Wear Behavior

Next, wheel-rail wear and rolling contact fatigue tests were carried out, the wheel/rail specimens experienced 5 000 dry cycles at room temperature, and then 20 000 dry cycles and 20 000 solid friction modifier cycles were carried out respectively. The total number of cycles under drying and solid friction modifier conditions was 25 000. The results show that MoS2 and PTFE as fillers have the most significant effect on the adhesion performance of solid friction modifiers, which can effectively improve the adhesion coefficient control ability of solid friction modifiers and effectively maintain the number of revolutions ; PF as a binder has the most significant effect on the crushing strength of solid friction modifier.

Based on the comprehensive adhesion performance, crushing strength and wheel-rail wear damage behavior, sample 1-3 # ( FM-A ) is the optimal ratio. At this time, the mass fractions of PF, MoS2, PTFE and Graphite are 20.4 %, 24.5 %, 36.7 % and 18.4 %, respectively. After applying the solid friction modifier, a friction control film is formed at the wheel-rail contact interface, so that the friction between the wheel-rail is transformed into the friction between the wheel-rail-friction control film, the force between the wheel-rail is reduced, and the adhesion coefficient is reduced to a suitable range, and the wear rate of the wheel-rail sample is reduced.

At the same time, when the fatigue crack passes through the wheel-rail contact zone, the fatigue crack opening is closed under the action of contact stress and solid friction modifier. Under these two effects, the solid friction modifier effectively reduces the surface damage, plastic deformation and fatigue damage behavior of the wheel and rail.