车轮材料表面h-BN/CaF_(2)/Fe基激光熔覆涂层组织与磨损性能  

Microstructures and Wear Properties of h-BN/CaF/Fe Based Laser Claddings on Wheel Material Surface

作　　者：丁昊昊 慕鑫鹏 祝毅[2] 杨文斌 肖乾 王文健[1] 郭俊[1] 刘启跃[1] DING Haohao;MU Xinpeng;ZHU Yi;YANG Wenbin;XIAO Qian;WANG Wenjian;GUO Jun;LIU Qiyue(State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China;State Key Laboratory of Fluid Power and Mechatronic Systems,Zhejiang University,Hangzhou 310027,China;School of Mechatronics and Vehicle Engineering,East China Jiaotong University,Nanchang 330013,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 [2]浙江大学流体动力与机电系统国家重点实验室,杭州310027 [3]华东交通大学机电与车辆工程学院,南昌330013

出　　处：《中国表面工程》2021年第4期139-148,共10页China Surface Engineering

基　　金：国家重点研发计划政府间国际科技创新合作重点专项(2018YFE0109400);四川省国际科技创新合作(2020YFH0057);中国博士后科学基金(2019M663548)资助项目。

摘　　要：激光熔覆铁基合金涂层的摩擦因数及磨损率均较高,h-BN和CaF_(2)作为固体添加剂已应用于激光熔覆处理,然而含h-BN和CaF_(2)的铁基熔覆涂层在列车车轮材料表面的磨损性能及最佳含量尚不清楚。因此,以不同比例的h-BN(0~2%)、CaF_(2)(2%~0)和Fe基合金(98%)粉末为熔覆材料,在列车车轮材料表面制备合金涂层,对激光熔覆车轮试样进行滚动摩擦磨损试验。结果表明:涂层微观组织主要由枝晶组织和共晶组织构成,硬度约800 HV0.3,表面存在残余压应力,其值为800~1 300MPa。加入h-BN粉末可将黏着系数降低至0.35~0.39,激光熔覆车轮试样表面以滚动接触疲劳损伤为主,裂纹在表面产生并在塑性变形层内扩展。随h-BN含量增加和CaF_(2)含量减小,微观组织尺寸、黏着系数、磨损率、滚动接触疲劳裂纹长度和深度均呈先减小后增加趋势。h-BN、CaF_(2)和Fe基合金质量比为1%:1%:98%时,涂层微观组织最致密、残余压应力最大、耐磨与抗疲劳性能最优。研究结果可为激光熔覆技术在列车车轮上的应用与优化提供理论与技术指导。The friction coefficient and wear rate of laser cladded Fe-based alloy were high.h-BN and CaF_(2),as solid additives have been used laser cladding.However,the wear performance and the optimum contents of the Fe-based cladding with h-BN and CaF_(2) are not clear.Therefore,coatings were produced on the railway wheel material using the laser cladding technology,from the powders with different proportions of h-BN(0 ~ 2%),CaF_(2)(2%~0),and Fe based alloy(98%).The rolling friction and wear tests were conducted.The results show that the claddings are composed of dendritic and eutectic phases.The hardness reaches around 800 HV0.3.Residual compressive stresses existed on the surface with the values of 800 ~ 1 300 MPa.Addition of h-BN powder could decrease the adhesion coefficient to 0.35~ 0.39.Rolling contact fatigue damage is predominant on the worn surface of the laser cladded wheel sample.Cracks initiate on the surface and then develop in the plastic deformation layer.With the increase in h-BN proportion and the decrease in CaF_(2) proportion,the size of microstructure,the adhesion coefficient,wear rate,and length and depth of rolling contact fatigue cracks are decreased and then increased.When the proportions of h-BN,CaF_(2),Fe based alloy are 1%: 1%: 98%,the cladding has the finest microstructure,the largest residual compressive stress,and the best anti-wear and anti-fatigue performance.The results could provide theoretical and technical guidance for the application and optimization of laser cladding technology on railway wheels.

关 键 词：激光熔覆 列车车轮材料 微观组织 磨损 损伤 

分 类 号：TH117.1[机械工程—机械设计及理论]