铌、钒含量对碳化物增强型无限冷硬铸铁轧辊显微组织的影响

Effect of Nb and V contents on microstructure of carbide reinforced indefinite chilled rolls

利用光学显微镜、扫描电子显微镜以及X射线能谱议,分析了碳化物增强型无限冷硬铸铁轧辊的基体组织特性、碳化物和石墨的形态及分布特点。结果表明,熔化过程中加入钒会显著降低石墨含量;随着铌含量的增加,NbC的数量相应增多;添加的铌含量超过一定限度,NbC大量偏聚于轧辊外层。

Effects of V and Nb contents on microstructure of the carbide reinforced indefinite chilled rolls made by small vertical centrifugal casting were investigated by use of optical microscopy , scanning electron microscopy and energy dispersive X-ray spectroscopy to analyze the matrix charateristic and the distribution and morphology of carbides and graphites formed during solidification .Microstructural analysis indicates that the amount of graphite is dramatically reduced by adding V element .The volume fraction of the carbides NbC increases with the Nb content increasing .However , if Nb content is over a critical value , large amount of the NbC carbide can be seriously segregated in the part section exterior .