临界退火对渗碳钢微观组织和耐磨性的影响  

Effect of Critical Annealing on Microstructure and Properties of Carburized Steel

作　　者：向永华 石磊[2] 李健[2] 胡玉婷 崔秀芳 金国[2] XIANG Yong-hua;SHI Lei;LI Jian;HU Yu-ting;CUI Xiu-fang;JIN Guo(Unit 92228,People's Liberation Army,Beijing 100072,China;Harbin Engineering University,Harbin 150001,China)

机构地区：[1]中国人民解放军92228部队,北京100072 [2]哈尔滨工程大学,哈尔滨150001

出　　处：《表面技术》2022年第10期200-208,259,共10页Surface Technology

基　　金：国家自然科学基金(52175163)。

摘　　要：目的研究临界退火后处理对真空渗碳层微观组织、硬度和耐磨性能的影响。方法采用临界退火后处理来保证17CrNiMo6渗碳钢表面耐磨性的同时,合理调控表面硬度。通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱仪(EDS)和激光共聚焦显微镜进行改性层微观组织结构的观察,利用维氏硬度计和高温摩擦磨损试验机等检测仪器进行改性层硬度与摩擦学性能的研究,对临界退火后处理改性层微观组织演变、元素分布、硬度以及室温环境下摩擦学行为进行详细分析。结果随着临界退火次数的增加,表面马氏体含量减少,残余奥氏体增加,而心部的回火马氏体基本不变,EDS面扫图谱显示元素分布较为均匀。与之对应的表面硬度呈下降趋势,心部硬度基本不变。在多次临界退火处理中,耐磨性依次为1次循环>2次循环>3次循环。其中,相比于3次循环处理,1次循环处理后的摩擦因数降低了42.8%,在改性层之间的磨损率分别为2.07×10^(-13)m^(3)/(N·m)(930℃渗碳处理试样),0.71×10^(-13)m^(3)/(N·m)(1次循环处理试样),5.23×10^(-13)m^(3)/(N·m)(2次循环处理试样)和4.21×10^(-13)m^(3)/(N·m)(3次循环处理试样),改性层在室温环境中的磨损机制主要为磨粒磨损、氧化磨损还伴随少量的黏着磨损。结论在17CrNiMo6渗碳钢进行临界退火处理后,获得了兼具高硬度、高耐磨性的临界退火后处理改性渗碳层,在一定程度上,合理的调控临界退火次数将改善渗碳改性层的耐磨性。In order to overcome the coordination between surface wear resistance and impact toughness of transmission parts(such as gears and shafts),surface chemical heat treatment is needed for surface chemical heat treatment.It is a special composite heat treatment technology,through vacuum carburizing to form a carburizing layer with high hardness and wear resistance,followed by critical annealing treatment can improve the properties of the modified layer without changing the matrix material,such as wear resistance.In this work,the effect of critical annealing heat treatment on the microstructure,micro-hardness and wear resistance of vacuum carburizing layer was investigated.Critical annealing post-treatment was used to ensure the surface wear resistance of 17CrNiMo6 carburized steel while reasonably regulating the surface hardness.Vacuum carburizing was carried out at 930℃in a vacuum carburizing furnace(ECM,ICBP-200-TG,including boost and diffusion),followed high temperature tempering(500-650℃),quenching(850-880℃),cryogenic treatment(‒80℃)and low temperature tempering(150-180℃),then by critical annealing heat treatment at 790℃×10 min and 840℃×20 min for the preparation process.The microstructure and phase composition of the modified layer were observed by optical microscope(OM,OLYMPUS-311U),scanning electron microscope(SEM,SU5000),energy dispersive spectrometry(EDS,ULTIMATELY MAX40)and X-ray diffraction(XRD,PANalytical B.V XPert Pro PW3040/60).The hardness and tribological properties of the modified layer were studied by Vickers hardness tester(HV-1000)and high-temperature friction and wear tester(HT-1000),etc.The 3D morphology of wear scars and wear rate were observed by laser confocal microscope.A detailed analysis of the microstructure evolution,element distribution,hardness and tribological behavior of the modified layer after critical annealing heat treatment was carried out.As the number of critical anneals heat treatment increased,the surface martensite content decreased,the residual austenite

关 键 词：渗碳 低碳钢 临界退火 耐磨性 

分 类 号：TH117[机械工程—机械设计及理论]