速度和载荷对凹坑织构乏油润滑摩擦学性能的影响

Effects of Sliding Speed and Load Levels on Tribological Properties of Dimple-Textured Surfaces Under Starved Lubrication

摩擦副表面加工特定的织构后会在不同速度和载荷以及严重乏油的条件下运行,比如设备的启停阶段。因此有必要研究极度乏油条件下速度和载荷对凹坑织构表面摩擦学性能的影响,为表面织构的实际应用进行前期探索。利用激光加工技术在45钢表面加工凹坑织构;在UMT-2型多功能摩擦磨损试验机上,采用球-盘式分别对织构和未织构试样进行乏油滑动试验;利用三维表面轮廓仪和扫描电镜等分析试样表面的磨损形貌。结果表明:相比于未织构试样,凹坑织构在不同速度和载荷下均能有效延长摩擦面间的乏油润滑状态,有良好的减摩效果,可降低摩擦因数约68%~75%。载荷对织构表面的摩擦学性能影响较大,在一定范围内摩擦因数随着载荷的增大而降低;但载荷过高时,在摩擦后期会出现摩擦因数的突然升高,表面磨损严重。

The frictional pairs with specially designated surface textures would serve in extremely starved lubrication under different sliding speed and load levels,when the machine starts up and shuts down.Therefore,it is essential to study the tribological properties of the dimple-textured surface in these conditions for the preliminary investigation of the application of dimple textures.The dimple textures were fabricated on 45 steel surfaces by laser processing.Experiments of textured and untextured specimens under starved lubrication were carried out on the UMT-2 multifunctional friction and wear tester using the ball-on-disk configuration.Morphologies of the worn surfaces were characterized by three-dimensional profile-meter and scanning electron microscope.The results show that the dimple-textured specimens can extend the period of starved lubrication regime under different sliding speed and load levels,and the friction coefficient can be reduced by about 68%−75%compared to the untextured specimens.The load levels have a significant influence on the tribological properties of the textured specimens.To some degree the friction coefficient decreases with the increase of the load level.However,server wear and dramatic increase of the friction coefficient are observed in the late period when the textured surface is overloaded.