Cr_(8)Nb_(3)CSiMnTi系堆焊合金的组织及耐磨性研究  

Research on the Microstructure and Abrasion Resistance of Hardfacing Alloys of Cr_(8)Nb_(3)CSiMnTi System

作　　者：艾孝文 龚建勋[1] 刘书同 肖志强 董海龙 AI Xiao-wen;GONG Jian-xun;LIU Shu-tong;XIAO Zhi-qiang;DONG Hai-long(School of Mechanical Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]湘潭大学机械工程与力学学院,湖南湘潭411105

出　　处：《材料保护》2023年第3期6-12,48,共8页Materials Protection

基　　金：湖南省自然科学项目(2021JJ30669)资助。

摘　　要：为解决中铬合金耐磨性不足的问题,采用“复合粉粒+H08A实心焊丝”埋弧焊方法制备Cr8Nb3CSiMnTi系中铬耐磨合金,借助X射线衍射仪(XRD)、扫描电镜(SEM)及附属能谱仪(EDS)等手段,研究了碳含量对该合金组织和耐磨性的影响。结果表明:中铬堆焊合金的基体由α-Fe构成,硬质相包括(Fe, Cr)7C_(3)、(Fe, Cr)_(3)C碳化物和(Nb, Ti)C等相;随着碳含量升高,α-Fe固溶的铬含量持续减小,沿晶(Fe, Cr)_(7)C_(3)型碳化物数量增多,形态从孤立状依次改变为树枝状、定向聚集态等,与(Nb, Ti)C相的间距随之减小。湿砂橡胶轮式磨损试验结果显示,随碳含量提高,堆焊合金的耐磨性先显著改善然后降低,这主要与沿晶碳化物(Fe, Cr)_(7)C_(3)数量提高以及其与(Nb, Ti)C相的间隔距离改变有关;堆焊合金的韧性则先持续下降,然后上升,这不仅决定于基体数量,而且与沿晶碳化物的形态及其分布有关;其磨损机制包括显微切削和剥落,以显微切削为主。For solving the problem of insufficient wear resistance of medium chromium alloy,medium chromium wear⁃resisting alloys belonging to Cr_(8)Nb_(3)CSiMnTi system were fabricated by submerged arc welding using composite powder particles(CPPs)and H08A solid wire as filler materials.The effects of carbon content on the microstructure and abrasion resistance of the as⁃prepared hardfacing alloys were investigated by X⁃ray diffractometer(XRD),scanning electron microscopy(SEM)and attached energy dispersive spectrometer(EDS).Results showed that the matrix of such medium chromium hardfacing alloys consisted ofα⁃Fe and contained such hard phases as(Fe,Cr)_(7)C_(3),(Fe,Cr)_(3) C and(Nb,Ti)C.With the increase of carbon content,chromium content in the solid solution of α⁃Fe matrix decreased continuously and the quantity of intra⁃granular(Fe,Cr)7 C 3 phase increased,whose morphology changed from an isolated shape into a dendritic one,and then a directional aggregation one.Meanwhile,the gap between intra⁃granular(Fe,Cr)_(7)C_(3) and(Nb,Ti)C became narrower.From the results of wet sand rubber wheel wear testing,it could be obtained that with the increase of carbon content,the alloys’abrasion resistance increased first and then decreased,which was mainly attributed for the increase of the quantity of intra⁃granular(Fe,Cr)_(7)C_(3) and the change of the gap between intra⁃granular(Fe,Cr)_(7)C_(3) and(Nb,Ti)C.Moreover,the toughness of hardfacing alloys decreased firstly and then increased,which was not only determined by the quantity of the matrix,but also related to the morphologies and the distribution of intra⁃granular carbides.Their wear mechanisms included micro⁃cutting and micro⁃spalling,and the former was the dominant.

关 键 词：复合粉粒 实心焊丝 堆焊 耐磨性 组织 磨损机制 

分 类 号：TG44[金属学及工艺—焊接] TH117.1[机械工程—机械设计及理论]