Research on Debris Characteristics and Wear Mechanism of Gear Material 18CrNiMo7-6 Used in Mining Reducer Under Dust-Contaminated Lubrication

The lubrication of mining reducer is subjected to the contamination of coal rock dust, and this contamination has extremely serious influence on the wear life of reducers. This paper examines the effects of coal dust and rock dust contamination on the wear of mine gearboxes, especially the wear mechanisms and particle characteristics under lubrication conditions of coal dust and rock dust mixtures of different particle sizes and contents. In the paper, 18CrNiMo7-6 alloy steel was used as the reducer gear material to simulate the actual working conditions, and friction and wear tests were conducted by CFT-1 comprehensive tester to analyze the wear particle characteristics under different contamination conditions. In the experiment, 80-mesh and 200-mesh coal dust and silica particles were used (80-mesh pore size is about 180 μm; 200-mesh pore size is about 75 μm), and different mass fractions of contaminant mixtures were set. The results show that under 80-mesh coal dust contamination, punctate pits, scratches and green halos appeared on the surface of wear particles, and the corrosion and abrasive effects were enhanced when the concentration increased, while 200-mesh coal dust contamination was characterized by black pits and green halos, and the abrasive effect was not obvious. Silica contamination showed significant cutting effects with red oxide wear particles. The synergistic effect of the two contaminants accelerated the wear of the material, and the wear particles were characterized by delamination, flaking and black pits. The study shows that the concentration and type of contaminants have a significant effect on the wear performance of the reducer.