NiCrBSi喷焊涂层组织和性能研究及其在球阀上的应用

Study on the Microstructure and Properties of NiCrBSi Spray Welded Coating and Its Application on Ball Valve

为了探明镍基喷焊层对球阀的防护机制,采用氧乙炔火焰喷焊工艺在20钢上制备了NiCrBSi涂层,通过扫描电镜和X射线衍射仪分析了涂层的组织形貌和相结构,并采用湿砂橡胶轮式磨粒磨损试验机和电化学工作站分别测试了该涂层的抗磨损和耐腐蚀性能。结果表明:NiCrBSi喷焊层与基体间存在过渡层和热影响区,涂层的显微组织以NiCr相为基体,基体相上较均匀地分布着粒状和杆状铬的碳化物和硼化物,这种组织使得NiCrBSi喷焊涂层具有较高的硬度、优异的耐磨性和抗腐蚀性能。因此,氧乙炔火焰喷焊工艺制备NiCrBSi涂层适用于球阀零件的表面防护,并且在生产实践中取得了很好的使用效果。

In order to explore the protection mechanism of nickel base spray welding layer on ball valve,a NiCrBSi coating was prepared on 20 carbon steel by oxy-acetylene flame spray-welding process. The microstructure and phase composition of coatings were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD),respectively. Furthermore,the wear and corrosion resistances of the NiCrBSi coating were tested by a wet sand rubber wheel abrasive wearing tester and electrochemical working station. Results indicated that transition and heat-affected zones were found to be generated on the coating/substrate interface. The microstructure of spray-welding coating was composed of Ni-Cr matrix,and granular and rod-like chromium carbides and borides distributed on the maxrix. This kind of microstructure made the NiCrBSi coating exhibit high hardness,excellent wear as well as good corrosion resistance. Therefore,the oxy-acetylene flame spray welded NiCrBSi coating was suitable for the surface protection of ball value,which had satisfied results in practical application.