Investigation of Dimple-Texturing on the Tribological Performance of Tungsten Carbide-AISI H13 Steel

Dimple texturing is the emerging practice to minimize friction and wear in frictional contact pairs. The tribological properties of the frictional contact pairs can be enhanced by optimizing the dimple-texture shape, dimple pitch and area density ratio. In this investigation, the frictional properties of dimple-textured tungsten carbide discs with hardened AISI H-13 steel pins was investigated using a pin on disc wear tester. Laser marking technology was employed to fabricate the polar arrays of honeycomb texture (HT) and spherical dimple-textures (ST) with 25% and 35% area density ratios. The sliding wear test was conducted for the dry and MoS2 (molybdenum disulphide) solid lubricant conditions to investigate the effect of coefficient of friction and wear rate of dimple structures with variation in disc rotational speeds in the range of 1000 rpm, 1250 rpm and 1500 rpm. The results indicate that, ST surface with MoS2 coating with 35% of area density at 1500 rpm exhibited best results in comparison to nontextured (NT) and HT with and without aid of MoS2 coating. The friction coefficient and wear rate for ST surface with MoS2 coating were 13.5% and 24% lower in comparison with HT at operating conditions of 35% of area density at 1500 rpm, respectively. Similarly, in comparison with NT the ST surface with an operating condition of 35% of area density at 1500 rpm exhibited 39.1% and 48.2% reduction in friction coefficient and wear rate, respectively.