“…Te total linear wear of rollers made of 30ChGSA steel is 3.259 μm and 5.21 μm when the friction pairs are lubricated with oil, respectively, in samples 1 and 2 (Table 4). Te wear of the lagging surface is 2.14 (sample 1) and 1.47 (sample 2) times higher than the wear of the leading surface, which is caused by a decrease in the endurance limit of the lagging surface as a result of the increase in the rate of fatigue failure in the conditions of diferent directions of friction forces in contact on leading and lagging surfaces [28,29].…”
Self-organization mechanisms of metastable dissipative structures during friction depending on base and oil functional additives for hypoid gears are considered. Research was conducted on a software-hardware complex with simulation of gears’ operation in rolling with slipping conditions in start-stop mode. Indicators of formation of wear-resistant dissipative structures include the following: improvement of antifriction characteristics, lubricant boundary layers’ formation, contact surfaces’ strengthening, and formation of heterogeneous deformation microrelief with a fine-grained structure. The formation of chemically modified boundary layers on 90% of the contact area of tribo-coupling elements ensures an increase in the wear resistance of leading and lagging surfaces by 2 and 1.4 times, respectively. The sclerometry method was used to establish that the formation of dissipative structures when lubricating tribo-coupling elements with various transmission oils can reduce deformation processes in metal near-surface layers by 23%. Highly viscous flavored lubricant with distillate oil and additive composition ensures wear-resistant dissipative structures with active components, including oxygen, sulfur, and phosphorus.
“…Te total linear wear of rollers made of 30ChGSA steel is 3.259 μm and 5.21 μm when the friction pairs are lubricated with oil, respectively, in samples 1 and 2 (Table 4). Te wear of the lagging surface is 2.14 (sample 1) and 1.47 (sample 2) times higher than the wear of the leading surface, which is caused by a decrease in the endurance limit of the lagging surface as a result of the increase in the rate of fatigue failure in the conditions of diferent directions of friction forces in contact on leading and lagging surfaces [28,29].…”
Self-organization mechanisms of metastable dissipative structures during friction depending on base and oil functional additives for hypoid gears are considered. Research was conducted on a software-hardware complex with simulation of gears’ operation in rolling with slipping conditions in start-stop mode. Indicators of formation of wear-resistant dissipative structures include the following: improvement of antifriction characteristics, lubricant boundary layers’ formation, contact surfaces’ strengthening, and formation of heterogeneous deformation microrelief with a fine-grained structure. The formation of chemically modified boundary layers on 90% of the contact area of tribo-coupling elements ensures an increase in the wear resistance of leading and lagging surfaces by 2 and 1.4 times, respectively. The sclerometry method was used to establish that the formation of dissipative structures when lubricating tribo-coupling elements with various transmission oils can reduce deformation processes in metal near-surface layers by 23%. Highly viscous flavored lubricant with distillate oil and additive composition ensures wear-resistant dissipative structures with active components, including oxygen, sulfur, and phosphorus.
“…The stress peak values decrease by 11.6% and 17.2% in work roll mid and later periods, respectively, with the work roll wear caused by the new shifting mode. Previous research has confirmed that contact stress has a significant influence on surface fatigue [3,21]. Roll fatigue can be postponed or the service period can be extended due to the improvement of work roll wear and the reduction of the contact stress. Figure 13. Wear comparisons between polygonal line mode and sinusoidal mode. Figure 14. Contact stress peak value comparisons at different work roll service periods.…”
Section: Work Roll Sinusoidal Shifting Modementioning
confidence: 95%
“…The stress peak values decrease by 11.6% and 17.2% in work roll mid and later periods, respectively, with the work roll wear caused by the new shifting mode. Previous research has confirmed that contact stress has a significant influence on surface fatigue[3,21]. Roll fatigue can be postponed or the service…”
Work roll wear is a key factor that affects the quality of the steel strip during the hot rolling process. With the demand for the same width steel rolling, work roll severe 'U' groove type wear appears. In this paper, it is found that work roll surface cannot reach their full potential with the conventional work roll shifting mode, which lead to severe and uneven work roll wear. As a solution, a sinusoidal cyclical shifting mode is proposed, and its effects on roll wear are investigated. As a result, work roll wear can be relocated from the central area to the sides. In the meantime, contact stress peaks reduce significantly in work roll mid and later service periods with a more even wear contour. Moreover, roll fatigue can be improved, while the adjustment range of equivalent work roll crown is not changed with the sinusoidal shifting mode.
“…TOR friction modifiers entail the direct application of lubricating material (TOR friction modifiers) onto the top surface of the steel rail. In order to maintain the safety of a train during its operation, TOR friction modifiers should have a "moderate friction coefficient level", i.e., the friction (adhesion) coefficient of the wheel tread/rail head interface should be controlled within the range of 0.1-0.3 [15]. In other words, TOR friction correction technology not only reduces friction to decrease wear loss but also meets the adhesion coefficient requirements for normal traction and braking of trains.…”
With the rapid development of railway towards being high speed and having heavy load capacity, the wheel–rail wear and rolling contact fatigue in the curve section with a small radius of freight have become the key problems in urban railways, which need to be solved urgently. The aims of this study were to compare the wear resistance with three different lubricating conditions on wheel–rail wear based on the wheel–rail rolling contact simulation tests. The wear loss, microhardness, and microstructure of the contacted surface of the rail were detected systematically. The results showed that the wear rates of rail were reduced by 71% for grease lubrication and 55% for solid lubrication, compared to those without lubrication. At the same time, the thickness of plastic deformation layer of rail samples were about 167 μm for the dry state, 138 μm for the solid lubrication state, and 128 μm for the oil lubrication state, respectively. It indicates that the thickness of the plastic deformation layer was significantly reduced under both grease and/or solid lubricating conditions. In addition, the microstructure of the deformation layer with two kinds of lubricated states was coarser and denser than that without lubricants. The average grain size of the deformation layer was approximately 0.22 μm under dry conditions and 0.32 μm under lubricated conditions. It also indicated that the changes in lubricants did not have a significant effect on the average grain size of the deformation layer. The results of the present study could provide theoretical reference for the development and design of lubricants used as rail materials.
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