摘要
采用明弧自保护法制备Fe-Cr-C-B-Nb系耐磨堆焊合金,借助光学显微镜(OM)、扫描电镜(SEM)和X射线衍射(XRD)等手段,分析堆焊层中的物相组成,探究熔池中硬质相析出顺序,研究B和Nb元素含量对其显微组织和耐磨性影响.结果表明,制备的堆焊合金显微组织为马氏体+残余奥氏体+M23(C,B)6+Nb C,Nb C先于M23(C,B)6生成.当堆焊层中B元素含量为0.21%,Nb元素含量为1.44%时,可以使堆焊合金有较高的硬度和耐磨性.洛氏硬度可达69 HRC±1.5 HRC,磨损量为0.037 6 g.过量的B元素不利于Nb C析出,而使Nb元素固溶强化硼化物和基体.耐磨性试验结果表明,M23(C,B)6和Nb C两种硬质相显著改善了Fe-Cr-C-B-Nb系堆焊合金的耐磨性.
Fe-Cr-C-B-Nb wear resistant flux cored wire was deposited by self-shield open arc welding. The phase composition and precipitation sequence of hard phases in the surfacing layer were analyzed. And the effect of B and Nb content on microstructure and wear resistance were also studied by optical microscopy( OM),scanning electron microscopy( SEM) and X-ray diffractometer( XRD). The experimental results showed that the microstructure consisted of the martensite,retained austenite,M23( C,B)6 and NbC phase. NbC phase was precipitated preferentially than M23( C,B)6 phase. When the content of B and Nb element reached 0. 21% and 1. 44% in the surfacing layer respectively,the hardfacing alloy indicated a high hardness and wear resistance. Therefore,the macro-hardness could reach69 HRC ± 1. 5 HRC and the wear loss was 0. 037 6 g for the FeCr-C-B-Nb hardfacing alloy. The excess B was not conducive to the precipitation of NbC phase,resulting in the solid solution strengthening of boride and matrix by Nb element. The results of abrasion test indicated that the exist of M23( C,B)6 and NbC significantly improved the abrasion resistance of Fe-Cr-C-B-Nb hardfacing alloys.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2018年第3期75-78,共4页
Transactions of The China Welding Institution
基金
辽宁省博士启动基金资助项目(20131079)
