Effect of lubricating composition with ultra-dispersive additives on fretting fatigue process

In this paper the possibility of improving the fretting wear resistance and anti-wear properties of fat in connection with the introduction of solid additives is considered. The topic work is to evaluate the effectiveness of lubricants with ultra-dispersive additives to reduce fretting-fatigue processes. The mechanism of fretting-fatigue consists of processes such as fretting corrosion and mechanical fatigue. Their interaction leads to the damage of the contact surfaces and leads to a drastic reduction in the fatigue endurance limit of parts. Fretting fatigue damage can occur in the bolt, pin, key and spline connections, surfaces of the parts, which were planted with interference, on surfaces of the shafts, clutches and other parts of friction unit. The results of investigation of grease on fretting-wear resistance, the distribution of the amount of wear from time are presented. The analysis of the state of the friction tracks and changeover of surface roughness after applying lubricant with solid additive is given. The experimental results suggest that the introduction of ultradisperse powder mixture of diamond and graphite in grease reduces the formation of fatigue cracks and improves the quality of the surface parts of friction units. This increases the actual contact area and reduces contact pressure. The values of tangential and normal stresses up to 18-20 % and the action of maximum shearing stress will move deeper into the material under the area of contact are also reduced. The application of lubricants with similar additives can increase the service life period of the mechanism twice as much. Test results can be used to select the lubricant used for the friction units operating in the mode of oscillation.