Experimental Evaluation of 100Cr6 Steel Microindented Surfaces Under Lubricated Nonconformal Point Contacts

Surface texturing has emerged as a promising approach to improve lubrication performance and reduce energy losses in mechanical systems. However, the influence of dimple size and density on the frictional behavior of lubricated nonconformal contacts remains insufficiently explored, especially using cost‐effective mechanical methods. This study aims to address this gap by investigating the effect of microindented textures, produced via Vickers microhardness indentation, on the lubricated tribological response of 100Cr6 steel spherical surfaces. Two load levels were used (0.5 N and 5 N), thus allowing us to investigate two dimple sizes (diagonal dimension of 10 and 30 µm) and two void ratios (VR) (5% and 17%). The tribological performance was evaluated under various sliding speeds using a ball‐on‐disk setup and two lubricants with different viscosities (CADT‐605 and Lubro Lam) to capture the full Stribeck curve. Results reveal that fine dimples with the highest VR (VR = 17%) significantly reduce the coefficient of friction (COF), by up to 40%, across all lubrication regimes, due to enhanced secondary lubrication. Conversely, large dimples increased the COF due to pile‐up formation and lubricant vortex generation. These findings provide new insights into the role of texture geometry in optimizing lubrication performance and pave the way for scalable and economic surface functionalization techniques in tribological applications.