Effect of Wavy Textures on Friction Reduction and Wear Resistance of Cam Tappets
The cam-tappet friction pair in internal combustion engines experiences severe wear under excessive loads and complex lubrication, reducing engine efficiency. This study employs laser surface texturing to fabricate biomimetic wavy textures on GCr15 steel, varying texture spacing to investigate the influence of area fraction on tribological performance. Ball-on-disk tests simulated cam-tappet point contact using AISI 1045 steel balls under 10 N load, 1.038 GPa contact stress, 150 r/min, and oil lubrication. Friction coefficient and wear rate were monitored, with surface morphology and elemental composition analyzed by SEM, 3D profilometer, and EDS. Fluent simulations modeled oil film pressure distribution for different spacings. All textured samples outperformed the untextured substrate. Optimal area fraction of 15–20% reduced friction coefficient by ~50% and wear rate by 60% compared to the substrate, while oil film pressure increased by 20% relative to a 9.75% area fraction texture. Simulation and experimental results concur. Excessive texture area fraction increases contact stress and wear, whereas insufficient area fraction yields low oil film pressure and poor hydrodynamic effects. Laser-fabricated biomimetic wavy textures effectively enhance the friction and wear performance of GCr15 steel through abrasive particle storage and hydrodynamic pressure augmentation, with an optimal area fraction of 15–20%.