Study On The Effect Of Molybdenum Spraying On Wheel Flange Wear Based On Archard Wheel-Rail Wear Model

Wheel-rail wear is the core problem of railway transportation in China.With the increase of train running speed,the increase of load and the number of train formation,the increase of wheel-rail side pressure,the serious wear of wheel flange,and the improvement of vehicle maintenance efficiency and rationality,the current lubrication technology alone can not meet the needs of railway development.The technology of Spraying Molybdenum on the flange surface presented in this paper is a new improvement on the traditional wheel-rail lubrication method.Molybdenum coating is prepared on the surface of wheel flange by thermal spraying technology.It can fundamentally reduce the wheel flange wear when the vehicle passes through the curve by utilizing the characteristics of high hardness,wear resistance,corrosion resistance and high temperature stability of molybdenum coating.At the same time,the derailment safety of the vehicle is improved.In this paper,the influence of molybdenum spraying on wheel flange wear is studied from the following aspects:1.The preparation of molybdenum coating powder and its spraying method were studied.The kinds of Molybdenum Coating with high bonding strength and its spraying method were obtained.At the same time,the mechanical properties of different kinds of coatings were tested,including bonding strength test,friction and wear performance test and impact performance test.Finally,the metal molybdenum coatings with the best comprehensive properties were determined.It was proved that the coatings had smaller friction coefficient and reduced wear under test conditions.The materials of the coatings were provided for simulation research.Performance parameters.2.The approximate calculation of friction coefficient of wheel-flange rail contact surface was carried out.The friction coefficient of molybdenum to steel and steel to steel was calculated by using the material performance parameters and friction coefficient model obtained from the experiment.The calculated results basically accord with the experimental results.On the other hand,the low friction coefficient of the molybdenum coating was verified.3.The suspension parameters of Zhuan K6 bogie are calculated,and the dynamic model of Zhuan K6-C70 freight car is established.The dynamic parameters of three different curve radius conditions are calculated.4.The finite element model of wheel-rail contact of E-wheel pair matching CN60kg/m rail used in K6 bogie is established.The distribution of contact stress on wheel flange surface under three different rail contact positions before and after molybdenum spraying is obtained by calculating the dynamic parameters and the performance parameters of molybdenum coating obtained from experiments.5.By using the deformation formula of wheel-rail Archard model,the stress distribution in the contact spot and the dynamic calculation results obtained from the finite element model of wheel-rail contact,the wear distribution in the contact spot before and after spraying molybdenum was obtained.The hardness parameters of the wheel flange before and after spraying molybdenum,the sliding distance of wheel-rail and the normal contact pressure of wheel-rail were calculated by combining the basic form of Archard model with the experimental results.Assume the wear volume of wheel flange before and after molybdenum spraying.The results indicate that spraying appropriate molybdenum coating on the rim of a common vehicle can effectively reduce the friction coefficient between the rim and the side of the rail when the vehicle passes through the curve,significantly reduce the wear of the rim and the side of the rail,and improve the derailment safety of the vehicle.That is to say,spraying molybdenum on the surface of wheel flange can not only achieve the effect of traditional wheel flange lubrication,but also overcome the shortcomings of traditional wheel flange lubrication.