Study On Fretting Wear Behaviors Of A High Strength Steel 22MnB5 By Tailoring Microstructures

Fretting wear is a surface degradation process invariably observed as two contacting bodies are subjected to small amplitude oscillatory movements,which has been one of main causes leading to tight fit assembly failure in railways industries,automotive,nuclear powder,aeronautical application,biological engineering,etc.In recent years,in order to meet the demand of industrial development for high performance of wear-resistant steel,multiphase microstructure alloy steels with excellent strength,toughness and strain hardening capabilities have attracted researchers’ attention.The wear behavior of alloyed steels is worth being investigated.However,the current studies on their fretting wear behavior mainly focus on the influence of fretting working condition,wear mechanism and mechanical properties.The correlation between fretting wear behaviors and the microstructural features which determines the properties of a material has been studied much less.Therefore,it is significantly important to deeply investigate the microstructure of an advanced alloyed steel and its effect on fretting wear resistance,to understand the correlation of microstructural features and fretting wear resistance,which will provide an important scientific theory and practical guiding.In this paper,typical alloy steels are selected to study the correlation of microstructural features and fretting wear behaviors,so as to develop the target microstructure for high fretting wear resistant steel.In this paper,the fretting wear behaviors of five different typical steels(InterstitialFree,IF steel;Full Martensite,FM steel;Dual Phase,DP steel;Quenching & Partitioning,Q&P steel;Twinning Induced Plasticity,TWIP steel)and 22MnB5 alloy steels with different microstructures were studied by using the ball-plane contact mode on the selfdesigned,high precision and low speed tangential fretting wear experimental device.Analyzed the friction coefficient,wear volume,wear scar morphology and wear mechanism by the means of optical microscope(OM),scanning electron microscope(SEM)and white light interference surface morphology.The main conclusions are as follows:1.The fretting wear volume of IF,DP,Q&P and FM steels increases with the increase of load,while the wear volume of TWIP steel first increases and then decreases with the increase of load.Under relatively low loads,the fretting wear resistance ranges from high to low for DP/Q&P/FM,IF,TWIP steels;under high loads,this rang is from high to low for DP/Q&P/FM,TWIP,IF steels.Low hardness multiphase alloy steels(DP,Q&P)exhibit the same even better fretting wear properties as high hardness martensite(FM)alloy steels.2.Under low load,the effect of martensite volume fraction on the fretting wear volume of DP steel is not significant.However,under high load,the wear volume of DP steel starts to be constant with the increase of the martensite volume fraction and then starts to decrease when the volume fraction of martensite increased to the highest(91%).Low hardness DP steel can also be obtained equivalent wear resistance with high hardness DP steel.Increasing the hardness of DP steel by increasing its martensite volume fraction does not improve its fretting wear performance.3.For the same component of DP steel,AIQ-DP steel with fine grain martensite and FIQ-DP steel with coarse grain martensite have the same fretting wear volume as MIQDP steel with uniform fine fiber martensite under the same wear condition,that is,the fretting wear performance is basically the same.The results show that the microstructure morphology has no significant effect on the fretting wear performance of the material,which are not identical with the sliding condition.4.Tailoring the morphology of microstructures based on desirable heat treatment can obtain low hardness materials without sacrificing fretting wear performance.DP steels with fine grain or fibrous martensite are the best microstructure for low-hardness and high fretting wear performance steels at present.The design of wear resistant alloy steels should not be hardness oriented,but should be to obtain target microstructure by tailoring and optimization.