机构地区:[1]吉林化工学院机电工程学院,吉林吉林132022 [2]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081 [3]上海交通大学材料科学与工程学院,上海200240 [4]大连交通大学材料科学与工程学院,辽宁大连116028
出 处:《表面技术》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)。
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 surfac
关 键 词:轮轨关系 D2/U71Mn轮轨材料 滑动磨损 白层 磨损机制
分 类 号:TH117[机械工程—机械设计及理论]
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