The Influence Of Solid Frction Modifier And Lubricants On The Friction And Damage Performances Of Wheel And Rail

The friction properties of wheel/rail interface are related to wheel/rail wear,running safety and maintenance cost.Therefore,it is one of the significant research issues in the field of wheel/rail system.To study the lubrication behavior of the wheel/rail has important guiding significance for reducing the wear and damage of the wheel/rail,extending the service life of the wheel/rail.In this paper,the influences of solid friction modifier(FM),solid lubricants and grease conditions on the adhesion and damage behaviors of wheel/rail were studied using the MMS-2A rolling wear tester.By analyzing the adhesion-creep curves,surface topographies,wear rates and rolling contact fatigue crack characteristics,the influence rules of solid FM,solid lubricants and greases on wheel and rail adhesion and damage performance were explored.The main conclusions are as follows.(1)Under dry condition,with the increase in slip ratio,the adhesion coefficient increased initially and then kept stable,reaching about 0.5 at the slip ratio of 9.43%.The adhesion coefficients of wheel/rail with the solid FM,solid lubricants and greases were lower than that under dry condition,and they were successively decreased.With the solid FM,the adhesion coefficient was in the range of 0.3-0.35.With the solid lubricants,the adhesion coefficients were about 0.2.With greases,the adhesion coefficients were less than 0.1.(2)Compared with the dry condition,solid FM,solid lubricants,and greases could decrease the wear rate of the wheel/rail.Under the solid FM condition,the wear rate of wheel was reduced to about 52% of that under dry condition,and the wear rate of rail was reduced to about 65%.Under the three solid lubricants conditions,the wear rates of wheels were decreased to 5%,77% and 42%,respectively,and the wear rates of rails were decreased to 3%,35% and 18%,respectively.Under the three greases conditions,the wear rates of wheels were decreased to 2%,1% and 2%,respectively,and the wear rates of rails were decreased to 10%,2% and 14%,respectively.(3)Under dry condition,the surface damage mechanism of wheel and rail materials was predominant by pits and partial oxidation,accompanied with obvious peeling,corrugation and spalling.Under the conditions of solid FM and solid lubricants,the damage form was slight peeling,and the fatigue crack length became shorter.The wheel and rail fatigue damage was reduced;Under the conditions of greases,the worn surface of the wheel sample was smooth and slightly peeled.But the rail damage was severe peeling and large spalling,the crack length became larger.The fatigue damage of rail was aggravated.