石墨添加量对Fe-Ti-V-C熔覆层组织及耐磨性的影响

通过激光熔覆在低碳钢表面获得Fe-Ti-V-C铁基熔覆层,利用X射线衍射(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)、能谱仪(EDS)、显微硬度计和磨粒磨损试验机,分析比较了熔覆粉末中不同的石墨添加量对Fe-Ti-V-C熔覆层物相组成、硬度和耐磨性的影响.结果表明:熔覆层中碳化物为均匀分布的TiVC2和VC.TiVC2呈多角块状或枫叶状,VC呈小块状或细长条状,且碳化物数量随石墨加入量的增加而增加.熔覆粉末中石墨添加量过多时,熔覆层中出现残余奥氏体.一定范围内,熔覆层的硬度与耐磨性随石墨加入量的增加呈现先显著提高后降低的趋势.进行多层熔覆时存在回火软化现象,且熔覆层硬度越高回火软化现象越明显.

Effect of Graphite Addition on Microstructure and Wear Resistance of Fe-Ti-V-C Cladding Layers

Fe-Ti-V-C Fe-based cladding layers were prepared on low carbon steel surface by laser cladding. The effects of addition amount of graphite in cladding powders on microstructure,hardness and wear resistance of cladding layers were investigated by means of X-ray diffraction,optical microscope,scanning electron microscope,energy dispersive spectrometer,micro-hardness tester and abrasive wear tester. The results show that the carbides (TiVC₂ and VC) were distributed evenly in cladding layers. The TiVC₂ was in form of either polygonal or a maple leaf shape while the VC was in form of a small block or a long and thin strip shape. The amount of carbides in cladding layers increased with the increasing addition amount of graphite. The presence of residual austenite in cladding layers was observed with high addition amount of graphite. The hardness and the wear resistance of cladding layers increased significantly and then decreased with the increasing amount of graphite. There was a tempering softening when multilayer cladding was employed. The higher the hardness,the more obvious the tempering softening.