Influence Research Of Metallography On The Dynamic Friction Coefficient And Wear Of Friction Pair

As the core of the railway transportation system,the wheel-rail friction pair plays an important role in guiding,pulling and braking during the operation of train vehicles.With the increase of train speed and axle load,the metallographic transformation on the surface of wheel-rail contact spots is more serious,which causes the friction coefficient and wear change of wheel-rail friction pair,and affects the service life of wheel and rail and the safety of train operation.Therefore,it is of great practical and economic significance to study the influence of metallographic organization on the friction and wear of wheel and rail,which can provide fundamental data to found some methods extended the service life of wheel and rail and to ensure he safety of train operation.This dissertation studies the influence of metallographic structure on the friction coefficient and wear of the friction pair by means of experimentation.It provides a certain reference data for understanding the friction coefficient and wear of wheel and rail.The main results obtained are as follows:(1)Under the same sliding speed and contact stress,the average friction coefficient is different due to different microstructures,but the change pattern of instantaneous friction coefficient is basically consistent with different friction pairs.At different sliding speeds and contact pressures,the variation tendency of the average friction coefficient of different friction pairs with different microstructure is basically the same and the range of variation is0.28 to 0.58 under experimental conditions.(2)At most sliding speeds and contact stresses,the average friction coefficient of the pearlitic friction pair is the smallest,and the average friction coefficient of the pearlite-martensite friction pair is the largest.The average friction coefficient of the latter is 13.0%to25.9%larger than that of the former.(3)The average friction coefficient of the pearlite-pearlite and martensite-martensite friction pair is smaller than that of pearlite-martensite friction pair.That is,the friction coefficient of the same metallographic structure friction pair is smaller than that of the different metallographic structure friction pair.The pearlitic friction pair has a small average friction coefficient,the friction coefficient of the martensite friction pair is large.That is,the pearlite structure reduces the friction coefficient of the friction pair,the martensite structure increases the friction coefficient of the friction pair.(4)At different sliding speeds and contact pressures,the variation tendency of the wheel wear volume with different microstructure is basically the same,and the maximum wear volume is less than 3.0×10~-33 mm~3/m·N under experimental conditions.At most sliding speeds and contact stresses,the wear volume of the pearlite-martensite friction pair is the largest,and the wear volume of the martensite-martensite friction pair is the smallest,the wear volume of the former is 1.5~8.0 times larger than that of the latter.(5)The wear volume of the pearlite-pearlite or martensite-martensite friction pair is smaller than that of pearlite-martensite friction pair.That is,the wear volume of the same metallographic structure friction pair is smaller than that the friction pair with different metallographic structure.The pearlitic friction pair has a large wear volume,the wear volume of the martensite friction pair is small.That is,the martensite structure reduces the wear volume of the friction pair,the pearlitic structure increases the wear volume of the friction pair.