微粒子喷丸高速动车组车轴钢疲劳性能的影响因素研究  

Research on the Fatigue Strengthening Influencing Factors of Micro Shot Peened High Speed Railway Axle Steel

作　　者：朱守东 张继旺[1] 卢琪 张浩楠 ZHU Shou-dong;ZHANG Ji-wang;LU Qi;ZHANG Hao-nan(State-Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学牵引动力国家重点实验室,成都610031

出　　处：《表面技术》2021年第12期140-148,166,共10页Surface Technology

基　　金：国家自然科学基金(51675445);牵引动力国家重点实验室自主研究课题(2019TPL-T06)。

摘　　要：目的研究微粒子喷丸EA4T车轴钢表面残余应力、组织结构强化层以及表面粗糙度对疲劳性能的影响。方法使用250℃保温2 h和550℃保温4 h的回火工艺对微粒子喷丸试样进行处理,研究微粒子喷丸试样表面残余应力和组织结构强化层对疲劳强度的影响。分析喷丸及回火处理试样表面的粗糙度、三维形貌、深度方向残余应力分布、X射线衍射峰、半高宽以及表面硬度,并进行旋转弯曲疲劳实验,确定疲劳性能。结果微粒子喷丸增加了试样的表面粗糙度,在表面引入了深度为80~100μm的残余压应力和加工硬化。微粒子喷丸将材料的疲劳极限由365MPa提高至470MPa。回火处理使得喷丸试样表面微观组织发生了回复,其硬度降低,残余应力松弛。250℃保温2 h和550℃保温4 h的回火处理使得喷丸试样的疲劳强度分别降低至450 MPa和430 MPa。结论微粒子喷丸在EA4T车轴钢试样表面引入的残余应力和组织结构强化层对疲劳强度的提高分别约为16%和23.8%,而表面粗糙度则降低了疲劳强度,降幅约为10%。In this study,the effects of the residual stress,the microstructure strengthening layer and the surface roughness on the fatigue performance of micro shot peened EA4 T axle steel were evaluated.Two tempering treatments of 250 ℃ for 2 h and 550 ℃ for 4 h were applied on the micro shot peened specimens,and the fatigue effects of the residual stress and the microstructure strengthening layer of shot peened specimens were carefully studied.The surface roughness,3 D morphology,residual stress distribution,X-ray diffraction peaks,full width at half maximum of X-ray diffraction profiles and surface hardness of the peened and tempered specimens were tested and analyzed,and the rotating bending fatigue test was performed to determine the fatigue performance.The results showed that the micro shot peening treatment increased the surface roughness,and introduced the compressive residual stress and work hardening with the depth of about 80~100 μm on the surface.Micro shot peening process improved the fatigue limit of the material from 365 MPa to 470 MPa.The surface microstructure of the tempered specimens recovered,the micro hardness decreased,and the residual stress released.And the tempering treatments of 250 ℃ for 2 h and 550 ℃ for 4 h reduced the fatigue limit of shot peened specimens to 450 MPa and 430 MPa,respectively.According to the test results,the fatigue strength influencing factors of micro shot peened EA4 T axle steel are quantitatively evaluated,and the results show that the residual stress and the surface microstructure strengthening layer increase the fatigue strength by about 16% and 23.8% respectively,while the surface roughness reduces the fatigue strength by about 10%.

关 键 词：喷丸 EA4T 残余应力 粗糙度 组织结构强化 

分 类 号：TG156.6[金属学及工艺—热处理]