Influence of micro-groove surface texture on the lubrication tribological properties of GCr15 bearing steel

Textured surfaces have been widely applied in the field of engineering for friction reduction, but research on the effects of different texture design parameters on the wear and fatigue resistance of bearing steel remains insufficiently explored. In order to improve the anti-wear and anti-fatigue performance and prolong the service life of bearing steel, surface texturing technology was applied to fabricate textured GCr15 bearing steel materials. In this work, micro-groove surface texture was designed by hydrodynamic theory, then, it was fabricated on the GCr15 bearing steel surface using nanosecond laser processing. The depths (15 mu m, 30 mu m), spacing (100 mu m, 200 mu m, 300 mu m), and friction angles (30 degrees, 60 degrees, 90 degrees) of micro groove were selected as the primary parameters for micro groove fabrication. The friction and wear tests and rolling contact fatigue (RCF) tests were conducted to investigate the lubrication tribological properties. The results indicated that micro-groove spacing of 300 mu m significantly reduces the coefficient of friction (CoF), depth of 30 mu m produces a higher hydrodynamic pressure, and friction angle of 60 degrees has a lower CoF value. Compared to the untextured samples, the RCF life of micro-groove surface texture sample is improved, and the median RCF life is increased by 36.5%. And it could be attributed to the dispersion effect of micro-groove surface texture on stress concentration. The findings indicate that a well-designed micro-groove structure can enhance the fluid dynamic pressure lubrication effect to a certain degree. In comparison to smooth surface specimens, those with micro-grooves exhibit reduced friction.