The Rolling Contact Fatigue of Rails and Experimental Research

Contact fatigue damage is one of the main failure modes of rail.This article summarizes the fatigue damage characteristics,the cause of formation,and the result of experiment research,also researches on the method of extending service life of rail steel. The factors that affect contact fatigue life are:Maximum contact stress-When the maximum contact stress is more than 1 200 Mpa,as it increases the contact fatigue life is decreased exponentially.When the maximum contact stress is less than 1 200 MPa,it has linear relationship with contact fatigue life;Residual stress,pressure stress and pulling stress-Range and maximum of pulling stress,and the distance to the surface were correlated with contact stress;Impurity in the rail-Many scholars pay great attention to it,they summarizes affecting factors of damage crack of sundries in the oxide,and affecting factors of crustiform crack is correlated with contact stress. This paper discussed the mechanism of subsurface distortion layer that is surface white layer,of impurity,of maximum shear stress,and of maximum pulling stress,in the formation of contact fatigue. To prolong the service life of rail steel,the paper puts forward the method of improving contact fatigue performance of metal material.