Characteristics Study of Pitting Wear during the Oil Lubrication Condition
| Autor: | Mu-Yuan Li, 李木元 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Technological progress has pushed industries to develop with regard to high precision and high accuracy. In particular, transmission components play a crucial role in maintaining the high operation performance of systems. The lifespan of the components can be extended by avoiding damages to the component surface, which can further effectively increase machine efficiency and reduce costs. However, gears, bearings, and screws often encounter failure, and friction frequently damages component surface, which is called surface pitting corrosion. This undermines the transmission components’ mechanical properties and may in turn lead to surface fatigue and failure. The objective of this study was to understand the development of pitting and its characteristic changes. Using lubricants comprising different percentages of water content and different concentrations of particles, this study simulated the decreasing performance of lubricant because of its long-term exposure to moisture and dust in atmospheric air. The experimental conditions closely reflected the conditions of the actual operation of transmission components. Accordingly, the changes in pitting corrosion could be discerned, which was required for determining the properties of transmission components. The results of the four-ball experiment of medium load (20kg, 50kg) showed that the friction coefficient of the added moisture (0.5wt% -1wt%) in the lubricating oil was larger than that of the lubricating oil containing the nano particles (Al2O3, SiO2). When heavy load (80kg, 110kg), the addition of nano particles (Al2O3, SiO2) will cause more friction between the two contact surfaces, which will lead to more serious interface friction and wear. The surface of the lubricating oil to which 0.05 wt% and 0.1 wt% of the nano particles Al2O3 and SiO2 were added was significantly scratched. The stepped load and independent segmentation experiments were used to observe the change of pitting morphology to initial pitting: small holes (2-3um) on the surface; medium-term pitting: a large number of holes and a large area (5-6um); post pitting: There are large and obvious irregular holes (10-30um), even peeling, and the surface will form wavy thermoplastic contact damage. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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