Experiment and Simulation Study on the Effect of Texture Depth on Tribological Properties of Stainless Steel Surface under Oil Lubricating Condition

Textured structures with different groove depths were fabricated by laser processing technique on stainless steel (SS) surface. The friction and wear behaviors of the textured surface with different groove depths were tested by a UMT friction and wear tester under the PAO6 lubricating condition. The morphologies of the textured surface before and after friction were characterized by a surface profilometer and a scanning electron microscopy. The experimental results were verified by theoretical simulation using CFD technique. According to the simulated results of ANSYS Fluent analysis, the influence mechanism of the groove depths on the tribological properties of the textured SS surface under oil lubricating condition was proposed. The result shows that the groove texture and the varying depths of the grooves remarkably affected the friction and wear behaviors of the modified SS surface under the PAO lubricating conditions. The modified SS surface with the groove depth of 10 μm exhibited the best anti-wear and friction-reducing abilities among all investigated samples, and its friction coefficient and wear rate were reduced by over 60% as compared to the untextured surface. This result was mainly attributed to the increased lifting force of the lubricant because of the formed wedge effect as the lubricating oil past the formed convergence region during the rubbing process. The increased lifting force improved the lubricating state the textured surface with 10 μm grooves and corresponded to its superior tribological properties at the rubbing process.