含铌中铬耐磨铸钢的摩擦磨损行为

Friction and Wear Behavior of Niobium Alloyed Medium Chromium Wear-resistant Cast Steel

使用立式MM-W1型销盘摩擦磨损试验机进行含铌中铬耐磨铸钢的室温干滑动摩擦磨损实验,用扫描电子显微镜(SEM)和能谱仪(EDS)观察磨损表面形貌和亚表层的组织变化,研究了Nb含量对这种钢的磨损行为和磨损机制的影响。结果表明,加入0.2%(质量分数,下同)的Nb形成的不连续棒状铌碳化物和晶粒细化提高了试验钢的耐磨性能。但是,Nb含量过高则使钢发生严重的组织变形和生成粗大网状碳化物,使磨损表面脱落而降低耐磨性能。随着试验载荷的增大,含0.2%Nb试验钢的磨损机理从轻微磨粒磨损向黏着磨损和氧化磨损转变。

Tribological behavior of experimental medium chromium wear-resistant cast steels with different niobium addition was investigated by using the MM-W1 pin-on-disc friction and wear tester at room temperature.The microstructure of the worn surface and subsurface were characterized by means of scanning electron microscopy and energy dispersive spectrometer,aiming to reveal the effect of Nb content on the wear behavior and mechanism for the steels.The results show that the addition of 0.2%(mass fraction)Nb can effectively increase the wear resistance of the steel due to the formation of discontinuous rod-like Nb carbides and the effect of grain refinement.An excess addition of Nb can reduce the wear resistance due to the occurrence of coarse mesh carbides and microstructural distortions,which then causes spallation of the worn surface.The 0.2%Nb test steel presented an evolvement of wear mechanism from slight abrasive wear to adhesive wear and oxidation wear.