截齿镍基钴包碳化钨激光熔覆涂层磨损性能研究

为解决掘进机截齿的磨损失效问题, 在截齿表面激光熔覆高耐磨的镍基(Ni)钴包碳化钨(WC-Co)涂层。以42CrMo钢为基体, Ni60B商用粉末为粘结相, 纳米WC-Co为增强相, 激光熔覆获得WC-Co陶瓷颗粒增强Ni基复合涂层。利用MM200环块磨损试验机, 测试熔覆涂层在干摩擦和水摩擦环境下的耐磨性能。采用显微硬度计测量涂层磨损前后的表面硬度, 电子扫描显微镜(SEM)、能谱仪(EDS)等观察熔覆涂层磨损前后的显微组织结构和成分变化。结果表明, 激光熔覆涂层可以提高截齿的耐磨性能, 磨损后熔覆层中的细小析出相起到了弥散强化作用, 熔覆层的表面显微硬度提高了10%。相同磨损条件下, 干磨损涂层硬度高于水磨损涂层硬度。

Study on Wear-resisting Property of Laser-claded Ni-based WC-Co Coatings on Cutting Teeth

Laser cladding technology was applied to form a Ni-based WC-Co coating with high wear resistance on TBM cutting teeth to solve the wear out failure. With Ni60B as the binding phase, WC-Co ceramic nanoparticle reinforced Ni-based composite coatings were claded on 42CrMo steel substrates. Wear-resisting performances of the coatings were tested with a MM200 ring-block wear testing machine in dry friction and water friction environment, surface hardness for the original coatings and worn ones were measured by microhardness tester, and their transforms in microstructure and composition were analyzed by SEM and EDS. It shows that the wear resistance of cutting teeth can be improved by laser-claded coatings, while the tiny precipitated phase in the worn claded layers displays a dispersion strengthening effect, and the surface microhardness of layers can be increased by 10%. Under the same wearing parameters, hardness of coatings after dry wear is higher than those after wet wear.