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Fe-C-Cr-V高铬堆焊合金的M7C3型碳化物及耐磨性

M7C3-type carbide and abrasion resistance of Fe-C-Cr-V high chromium hardfacing alloys

  • 摘要: 采用药芯焊丝埋弧堆焊方法制备含有0.9%~3.0%C,15%~20%Cr,2.0%~3.0%V的高铬合金.借助光学显微镜、扫描电镜和X射线衍射等手段,研究其显微组织及碳化物分布形貌.结果表明,其显微组织由马氏体+铁素体+奥氏体+初生M7C3+(Fe,Cr)3C+TiC等相组成.通过优化药芯焊丝组份及调整堆焊速度,获得了沿堆焊表面垂直方向定向分布的初生M7C3型碳化物,电子能谱分析显示该碳化物为(Fe,Cr,V)7C3.此外,考察了碳含量对高铬堆焊合金硬度及耐磨粒磨损性能的影响.表明其耐磨性优良,其中15~25 μm M7C3型初生碳化物颗粒有效阻碍磨粒的显微切削运动,显著改善了耐磨性.

     

    Abstract: High chromium hardfacing alloys containing 0.9-3.0%C,15-20%Cr,2.0-3.0%V(wt.%) were deposited by flux-cored wire submerged arc welding(SAW).The microstructure and carbide morphology were investigated by optical microscopy(OP),scanning electron microscopy(SEM) and X-ray diffraction(XRD).The microstructure consists of martensite,ferrite and austenite,carbide such as primary M7C3,(Fe,Cr)3C and TiC etc.Orientational M7C3-type carbide grains distributing in the plane vertical to the hardfacing surface were obtained by the optimization of flux-cored wire and welding speed.The analysis of energy dispersive spectrometer(EDS) indicated that M7C3 type carbide was(Fe,Cr,V)7C3.In addition,the effects of carbon content on hardness and wear properties were evaluated.Experimental results demonstrated that the abrasion resistance of Fe-C-Cr-V hardfacing alloys was excellent.Dispersed primary carbides of M7C3 with the size of 15-25 micron can effectively impede the micro-cutting movement of abrasive particles and deliberately improve abrasion resistance of the hardfacing alloys.

     

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