高铬明弧堆焊合金的显微组织及耐磨性

采用金属粉型药芯焊丝自保护明弧焊方法制备了含有（质量分数，％）Cr21—23，C3．5～4．2，Si1．4—1．6，B0～1．8的耐磨合金．采用光学显微镜、X射线衍射仪、扫描电镜和电子能谱仪，研究B4C对其显微组织及耐磨性的影响，分析了明弧堆焊熔池凝固特点及Si，B等元素对焊缝脱氧的影响．结果表明，Si5C3可充当初生M7C3相的非均匀形核核心，随着外加B4C含量增加，初生M7C3相体积分数和尺寸均显著增加，形态由弥散分布转为聚集排列．此外，湿砂磨粒磨损试验和表面磨损形貌分析结果显示其耐磨性取决于初生M7C3相尺寸及分布形态，微观剥落为主要磨损机理．

Microstructure and abrasion resistance of high-chromium open arc hardfacing alloys

Wear-resisting alloys containing Cr 21%~23%, C 3.5%~4.2%, Si 1.4%~1.6%, B 0%~1.8%(mass fraction) were deposited by metal powdered-type flux-cored wire self-shielded open arc welding.The effects of B₄C content in flux-cored wire on the microstructure and abrasion resistance as well as the solidifying characteristics of weld puddles and the effects of Si, B on the deoxidization of weld beads were studied by the methods of optical microscopy(OM), X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS).It shows that Si₅C₃ can act as a good homogeneous nucleate core of primary M₇C₃ grain.With the addition of B₄C particles, the volume fraction and the size of primary M₇C₃ grains increase remarkably and their morphology changes from dispersion to aggregation.In addition, the results of wet sand rubber wear tests and the analysis of worn morphology indicate that abrasion resistance depends on the size and the morphology of primary M₇C₃ grains and micro-spalling is the dominating wear mechanism.