Tribological Performance of Bearing Steel with Bi-triangular and Circular Textures under Lubricated Sliding

The present study is conducted to unravel the effect of density, shape of dimples and sliding speed on the tribological performance of laser textured bearing steel under single drop lubrication. Four discs of bearing steel with circular and bi-triangular dimples with 7 and 20% densities in the spiral arrangement were tested at different speeds of 0.2, 0.8, 1.4 and 2 m/s at a constant load of 10 N using a pin-on-disk unidirectional tribometer against a counterface pin of the same material under flat-on-flat configuration apart from an untextured disc. The results suggest that a lower density of bi-triangular dimples performed better in terms of reduced coefficient of friction and wear rate as compared to circular dimples or bi-triangular dimples with 20% density. The observed behavior has been attributed to an optimal number of dimples in the contact zone in case of a spiral array and micro-bearing effect arising thereof apart from the usual function of dimples, i.e., entrapment of wear particles and reservoir of lubricant.