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51.
宝钢条钢厂2号初轧机轧辊的锯齿型磨损对辊耗、钢坯质量有一定的影响。本文试分析了该锯齿型磨损的产生原因及产生机理,并在实践中进行了验证。 相似文献
52.
A mechanical approach to the nuclear fuel fretting problem is studied in this paper to find a possible and efficient way of a wear restraint. Two different contours of the spacer grid spring and dimple were developed to increase the contact area. Fretting wear experiments were carried out for the developed springs and tube specimens. Contact forces of 10 and 30 N, and slip displacements of 50–100 μm were applied under the environment of air as well as water at room temperature. Wear scars on the rods were examined to observe the effect of the mechanical approach on the wear. Especially, the influence of a contour deviation which occurred during fabrication and the wear particle accumulation in the clearance region were investigated in detail. It was found that the contact shape influenced the feature and the behavior of the length, width and volumetric shape of the wear. For the model of fuel fretting wear, equivalent depth (De) is suggested as a new parameter that can represent the wear severity. 相似文献
53.
Fretting behavior of Cu–Al coating on Ti–6Al–4V substrate was investigated with and without fatigue load. Soft and rough Cu–Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface, which caused an increase in tangential force during the fretting test under gross slip condition. Fretting in the partial slip condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of fatigue loading condition and extended from partial slip to gross slip regimes. As an alternate but simple approach for wear analysis, accumulated relative displacement range was correlated with the wear volume. This also resulted in a linear relationship as in the case of accumulated dissipated energy suggesting that the accumulated relative displacement range can be used as an alternative parameter for dissipated energy to characterize the wear. When the maximum wear depth was equal to the thickness of Cu–Al coating, harder Ti–6Al–4V substrate inhibited further increase in wear depth. Only when a considerable energy was supplied through a large value of the applied displacement, wear in the substrate material could occur beyond the thickness of coating. 相似文献
54.
A theoretical basis is presented for a previous fully empirical development of the unified approach to fretting that was based on a new similarity criterion termed slip index. It is shown that the slip index can be analytically derived from any friction loop geometry and hence, can be used for the characterization of any fretting system. 相似文献
55.
The problem of a proper lubrication under low‐speed small oscillatory movement can be a decisive factor for the reliability of various components. There is a need to characterise the lubricious behaviour of the interface under oil‐bath fretting wear conditions for ball bearing applications. Fast and reliable methods to quantify this behaviour for broad range of mechanical conditions are proposed and validated. Pure sliding reciprocation induces mixed lubrication mode. It was found that transient film profiles depend on the non‐Newtonian response of the oils and the type of motion. Running‐in period has a crucial importance for the tribofilm formation, and is a result of the interplay of the oil‐sliding surfaces interface and is directly connected with the total energy dissipated from the contact region. The stability of structured tribofilm in steady‐state period relies on the balance between the competitive processes: replenishment of the oil to the contact and ejection of the oil pending the oscillatory movement. The phenomenon of starvation was observed when the system was moved away from dynamical equilibrium and the growth of the dissipated energy was spotted. A proposed methodology provides the evaluation of the lubrication properties of the oil in a quantitative way. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
56.
Fretting fatigue is an adhesive wear mechanism caused by repetitive tangential micro-oscillation between two contacting materials
pressed together under cyclic load. Bioimplants, such as hip joints and bone plates, are prone to undergo fretting fatigue
failures during their service within the body. This article presents the fretting fatigue damage characterization of physical
vapor deposition (PVD) TiN-coated biomedical titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb) subjected to cyclic loads. The PVD
TiN layer delayed the damage because of superior tribological properties compared with uncoated alloys. Delamination and abrasive
wear damage of TiN at contact caused failure of the alloy. Friction coefficient curves of the PVD TiN-coated pair showed an
irregular pattern caused by the influence of wear particulates and Ringer fluid at the contact. 相似文献
57.
58.
Hard, wear-resistant and self-lubricating titanium carbide coatings produced by chemical vapour deposition are used to improve the tribological properties of high precision components for mechanisms that must operate in extreme environments.The two main space tribology areas, where such coatings have made a breakthrough, are ball bearings and fretting joints. This paper presents a brief historical background of the technology, the main coating properties and some areas of application. 相似文献
59.
60.
以金和锡作为贵金属镀层和非贵金属镀层的代表,进行不涂和涂覆润滑剂的微动实验,除测量接触电阻外,还在扫描电子显微镜和X射线能谱仪下对接触区域进行了观察和分析。 相似文献