Study On The Effect Of Friction Modifier On Adhesion And Damage Properties Of Wheel/Rail

The adhesion level at the wheel-rail interface affects the wear and damage of the wheelrail materials,and the traction and braking performances of the train,etc.Using friction modifiers to adjust the adhesion of the wheel-rail interface can improve the adhesion level between the wheel and rail,and decrease the vibration and damage.Therefore,the research on the influence of friction modifiers on the wheel-rail adhesion,wear and damage behaviors has important guiding significance and engineering value for reducing the wheel-rail wear and damage and improving the wheel-rail service life.In this paper,the MJP-30 A rolling wear and contact fatigue testing machine was used to study the influence of different particle concentrations of four kinds of particle friction modifiers(alumina,silica,zinc oxide and titanium carbide)on the wheel-rail adhesion.The influence of four kinds of particle friction modifiers with the optimum concentrations(PFM1,PFM2,PFM3 and PFM4)on the wheel/rail adhesion,wear and damage was analyzed.The mechanical stability and the influence of feeding amount of the water-based friction modifiers(water-based FM1 and FM2)on the adhesion were studied.The influence of the water-based friction modifiers on the adhesion,wear and damage of the wheel and rail under the optimal feeding amount was analyzed.The main conclusions of the master thesis are as follows:(1)With the presence of friction modifier of alumina,silica,zinc oxide or titanium carbide particles,the wheel-rail adhesion coefficient increased first and then decreased with the increase in particle concentration.The average adhesion coefficient reached the largest value when the particle concentration was 10%.(2)The adhesion coefficient under the water medium was about 0.16.The adhesion coefficients under PFM1,PFM2 or PFM4 media were larger than under the water media,and the adhesion coefficient under PFM3 media was almost the same as that under the water media.Under the PFM1,PFM3 or PFM4 media,wheel and rail wear rates were higher than those under the water medium,under the PFM2 medium,the wheel and rail wear rates were 73.1%and 60.8% of those under the water medium.Rail damage under the PFM2 media was slight,only slight skinning and cracks appeared,the crack length and depth were small and the angle was large.(3)The mechanical stability of water-based FM1 was better than that of water-based FM2.The optimal feeding amounts of the water-based FM1 and the water-based FM2 were 14 μl and 8 μl,respectively.(4)The wheel and rail wear rates under the dry condition were 38.89μg/m and 46.73μg/m,respectively.Under the water-based FM1 or FM2 medium,the wheel and rail wear rates were only 36.5% and 44.9% or 37.6% and 98.7% of those under the dry condition,respectively.Peeling and cracking occurred on the surface of the wheel and rail under the dry condition;the surface damage of wheel and rail under the water-based FM1 medium was milder than that under the dry condition,and only micro-cracks appeared.The length,depth and angle of the crack were smaller than those under the dry condition;under the water-based FM2 medium,obvious peeling and cracks occurred.The length,depth and angle of the cracks were greater than those under the dry condition.