Simulation and Experimental Study on Tribological Properties of Herringbone Texture on 42CrMo Bearing Alloy Steel Surface

For reduced friction and enhanced anti-wear capability of 42CrMo alloy steel, herringbone textures with different features were fabricated on its surface using laser printing technology. The tribological properties of samples without and with different texture area occupancies (9.9, 13.3, 17.6, 22.1, 25.1, and 31.2%) were evaluated and compared using a MRTR multifunction friction and wear test machine. To understand the influence of area occupancy on tribological properties, in addition to the experimental study, the performance of the herringbone texture with different area occupancy rates was analyzed via fluid simulation using the ANSYS Fluent software. The simulation shows that the texture causes a hydrodynamic pressure effect on the oil lubricant. When the lubricating oil flows over or through the surface texture, positive and negative pressure regions are generated in the oil film. Negative pressure is generated in the divergent area, and positive pressure is generated in the convergence area. The results of the friction and wear tests show that samples with certain area occupancy textures have lower friction coefficients than smooth surfaces without texture, and when the area occupancy rate is too high, friction and wear cannot be reduced. Under the same operating conditions, the best tribological performance is achieved when the texture area occupancy rate is 17.6%, corresponding to a 26.6% reduction in the coefficient of friction. The appropriate surface texture morphology and area occupancy can lead to markedly improved tribological properties of the friction pair surface.