Influence Of Wheelset Press-fit Technology And Surface Heat Treatment On Fretting Fatigue

The axle of locomotive is the most important part of railway rolling stock running gear.Axle fatigue failure generally occurs in the body and the axle shaft axle at the wheel seat,and it is difficult to detect the greater harm because the fretting fatigue damage occurred at the axle wheel seat.Therefore,the study of the axle press-fit technology,axle fretting fatigue damage and the possibility of fretting crack initiation have guiding significance.In this paper,using the finite element analysis software ABAQUS finite element simulate the process of the hydraulic injection of the installation.Analyzing under different amount of interference the stress distribution and mating area of the axle after quenching and tempering treatment and surface hardening treatment after the press-fit to the completion.Meanwhile,the finite element study the contact stress,normal stress,slippage and the possibility of crack initiation the axle quenched and surface hardening process under the bending load.In predicting crack initiation possibilities,analyze the impact of the fretting fatigue of axle by Ruiz.Finally,having a comprehensive evaluation for the shaft fretting fatigue damage under different amount of interference,different heat treatment.Specific results are as follows:The comparison of fitting process:(1)Verify coefficient of friction of half lubrication is the half of dry friction and lubrication.(2)The contact stress and normal stress of the axle surface after quenching and surface hardening treatment increase with the increase of the amount of interference.(3)Compared model of having hydraulic press-fi and no-hydraulic press-fit,whether it is the quenching or surface hardening treatmen,the process of the hydraulic injection of the installation exist residual stress.The comparison under bending load:(1)Under bending load,because the surface hardening make the elastic modulus of the surface increases and increases the rigidity,the contact stress and normal stress of surface hardening are larger than the quenching.With the increase of the amount of interference slip is reduced and surface hardening process is smaller than the quenching.(2)Under bending loads,compared model of having hydraulic press-fi and no-hydraulic press-fit,residual stress leads to the distribution of contact stress and normal stress.For the contact stress,the residual stress has great influence on the maximum of contact stress in the upper left and upper right and lower right area.For normal stress,residual stress also has a certain effect on the upper right and lower right area.(3)By Ruiz criterion,with the increase of the amount of interference K increases.In other words,the amount of interference is more easy to crack initiation of fretting.At the same time,fretting fatigue cracks may be initiated at a certain position in the inner region of the wheel seat over the amount of 0.26mm,0.28mm and 0.30mm conditions.