摘要
目的研究滑动磨损条件下,载荷变化对D2车轮钢表层微观组织和磨损性能的影响。方法利用MRH-30(环块)滑动摩擦磨损试验机进行滑动磨损试验。使用金相显微镜(OM)、场发射扫描电镜(SEM)、X射线衍射仪(XRD)和场发射透射电镜(TEM)等设备,分析滑动磨损后表层微观组织、表面磨损形貌和硬度变化。结果不同载荷条件下,随着磨损时间的增加,轮轨试样磨损量逐渐增加。200 N载荷条件下,(环状)车轮试样的磨损量大于100 N车轮试样磨损量,但200 N钢轨(块状)试样的磨损量却低于100 N钢轨试样。滑动磨损后,在不同载荷条件下,车轮试样表面主要形成长条状白层和不连续的月牙状白层。在200 N载荷条件下,由于车轮试样的磨损量较高,其白层厚度和表面白层硬度都小于100 N载荷条件下的车轮试样。在200 N载荷条件下,车轮试样表面更易形成不连续的月牙状白层。由于轮轨试样表面存在微凸体,高载荷会加速车轮试样表面局部微凸体发生严重塑性变形,导致月牙状白层的形成。在白层内片状渗碳体发生明显溶解和铁素体晶粒显著细化。结论车轮表面白层对磨损性能有明显影响。滑动磨损过程中,高载荷条件下,月牙状白层和周边微观组织界面易形成裂纹,裂纹会逐渐沿着界面向内部扩展,导致不连续月牙状白层发生剥落,降低车轮试样表面的硬度,加速车轮试样磨损。另一方面,高载荷会加速无白层区域塑性变形,导致其形成棘轮失效,从而加速磨损。
The work aims to investigate the effect of load on surface microstructure and property of D2 wheel steel under sliding wear.The sliding wear tests were conducted on the MRH-30 sliding wear machine.The microstructure evolution,surface wear morphology and micro-hardness at different depth from surface after sliding wear under different load conditions were analyzed with an optical microscope,a field emission scanning electron microscopy,an X-ray diffractometer and a field emission transmission electron microscopy.The weight loss of the wheel and rail samples increased gradually with the increase of sliding wear time.After certain sliding wear time,the weight loss of the wheel sample under 200 N condition was higher than that of the wheel sample under 100 N condition.On the contrary,the rail sample under 200 N condition exhibited better wear resistance.After sliding wear,the rod-like white etching layer(WEL)and the discontinuous crescent-shaped WEL were formed at the wheel sample surface under different load conditions.In WEL,the lamellar cementite was dissolved obviously and ferrite grains were refined,whose size was about 100 nm.The thickness of the WEL of the wheel samples increased with sliding wear time increasing under different load conditions.However,the thickness of WEL under 200 N condition was thinner than that under 100 N condition after different sliding wear time owing to high weight loss.The micro-hardness of the WEL was high due to the dissolution of a large amount of cementite and the formation of nano-ferrite grains.The surface hardness of the WEL under 200 N condition was lower than that under 100 N condition.In WEL,the hardness showed a gradient from the surface to the plastic deformed layer.High weight loss reduced the thickness of the WEL,thus resulting in the decrease of surface hardness in WEL under 200 N condition.The discontinuous crescent-shaped WEL was more likely to form at the wheel sample surface under 200 N condition.Due to the existence of asperity on the wheel and rail sample surface,high load could accelerate the severe plastic deformation of local asperity on the wheel and rail sample surface,resulting in the formation of discontinuous crescent-shaped WEL.The discontinuous crescent-shaped WEL signification affected the wear property of the wheel sample.During sliding wear process,under 200 N condition,the cracks were easy initiated at the interface of discontinuous crescent-shaped WEL and the microstructure surrounding discontinuous crescent-shaped WEL.Moreover,the cracks also were easy to propagate at the interface of crescent-shaped WEL and the microstructure surrounding crescent-shaped WEL gradually,causing the flaking of discontinuous crescent-shaped WEL.The flaking of discontinuous crescent-shaped WEL could increase the wear loss of the wheel sample.When the discontinuous crescent-shaped WEL was flaked,the difference of hardness between the wheel sample and the rail sample further was expanded.The wheel sample wear was further accelerated during sliding wear process.On the other hand,high load could accelerate plastic deformation in no WEL area to cause the ratcheting failure and then accelerate the wear failure of the wheel sample.
作者
刘春鹏
张关震
李传维
顾剑锋
索忠源
任瑞铭
LIU Chunpeng;ZHANG Guanzhen;LI Chuanwei;GU Jianfeng;SUO Zhongyuan;REN Ruiming(School of Mechanical and Electrical Engineering,Jilin Institute of Chemical Technology,Jilin Jilin 132022,China;Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;School of Materials Science and Engineering,Dalian Jiaotong University,Liaoning Dalian 116028,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第11期150-159,共10页
Surface Technology
基金
国家重点基础研究发展规划项目(2015CB654802)
国铁集团科研课题(K2021J007)。
关键词
轮轨关系
D2/U71Mn轮轨材料
滑动磨损
白层
磨损机制
wheel-rail relationship
D2/U71Mn wheel-rail materials
sliding wear
white etching layer
wear mechanism
