The Effect of Extreme Pressure (EP) Lubricants on the Life of Rolling Element Bearings

Wan, G.T.Y.; Lankamp, H; Vries, Andrew de; Ιωαννίδης, Ε.

doi:10.1243/pime_proc_1994_208_379_02

Cited by 8 publications

(6 citation statements)

References 4 publications

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“…The results from the ThCRB and DGBB tests performed in this study with oil A/A1 point out that certain oil formulations can have an effect on bearing performance under certain conditions. 13,14 In this case, also leading to the formation of WECs and the associated bearing failure. For the first time, this study shows that the described effect seems to affect bearings with different geometry, both axial and radial bearing types in a reproducible way.…”

Section: Influence Of Oil Compositionmentioning

confidence: 99%

“…It is known that certain oil-additive systems reduce the bearing life, 13,14 although the precise mechanism on how this happens is not very clear. It is assumed that some sort of weakening effect occurs in the bearing material so that cracks initiate even under relatively low stresses.…”

Section: Introductionmentioning

confidence: 99%

“…Yet, already in the 1980–1990s, studies reported bearing life reduction factors of 2 to 10 when specific EP/AW where added to base oils. 13,14,31–33 At the time, investigations were not looking specifically for WECs and it is unknown if they occurred during such tests. The interpretation in those studies mainly relied on mechanical aspects of the tribolayer formation in presence of EP/AW additives: friction, roughness, and wear rate.…”

Section: Introductionmentioning

confidence: 99%

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The influence of lubricant formulation on early thrust and radial bearing damage associated with white etching cracks

Ruellan

Stadler

Rydel³

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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In the past, results have shown the influence of oil-additive systems in the life of rolling bearings, also hypotheses have been formulated on the influence of lubricant formulation on the development of early bearing damage associated with white etching cracks. In some earlier work of the authors with different operating conditions, early damage, and white etching cracks had been generated by mechanical stresses. In this study, tests with custom-made lubricants have been performed on thrust as well as radial bearings to clarify some assumptions. The tested oils differ only by the presence of three additives, but only one oil has led systematically to white etching cracks despite the fact that both oils lead to similar mechanical stresses. The results confirm that under mixed lubrication conditions with certain lubricant formulations, early damage, in particular white etching cracks, can be influenced by the oil-additive system likely affecting the bearing steel. Hypotheses are formulated and the influence of different parameters is discussed. This paper, combined with earlier work of the authors, confirms that the understanding and solution to an early bearing damage associated with white etching cracks can only be validated using the appropriate test method.

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Section: Influence Of Oil Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of lubricant formulation on early thrust and radial bearing damage associated with white etching cracks

Ruellan

Stadler

Rydel³

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…A number of additives found in lubricants have been shown to promote WSF occurrence, these include; extreme pressure (EP) and anti-wear (AW) additives consisting of sulphur and phosphorus compounds [66,67], where sulphur aids in hydrogen diffusion by preventing atomic hydrogen recombination [68] and formulations of AW zinc dithiophosphates (ZDDP/ZnDTP/ZnDDP) with detergent/rust preventative calcium sulphonate additives [6,61,[69][70][71][72][73][74].…”

Section: Influence Of Oilmentioning

confidence: 99%

Thermal Desorption Analysis of Hydrogen in Non-hydrogen-Charged Rolling Contact Fatigue-Tested 100Cr6 Steel

et al. 2017

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Hydrogen diffusion during rolling contact fatigue (RCF) is considered a potential root cause or accelerator of white etching cracks (WECs) in wind turbine gearbox bearing steels. Hydrogen entry into the bearing steel during operation is thought to occur either through the contact surface itself or through cracks that breach the contact surface, in both cases by the decomposition of lubricant through catalytic reactions and/or tribochemical reactions of water. Thermal desorption analysis (TDA) using two experimental set-ups has been used to measure the hydrogen concentration in non-hydrogen-charged bearings over increasing RCF test durations for the first time. TDA on both instruments revealed that hydrogen diffused into the rolling elements, increasing concentrations being measured for longer test durations, with numerous WECs having formed. On the other hand, across all test durations, negligible concentrations of hydrogen were measured in the raceways, and correspondingly no WECs formed. Evidence for a relationship between hydrogen concentration and either the formation or the acceleration of WECs is shown in the rollers, as WECs increased in number and severity with increasing test duration. It is assumed that hydrogen diffusion occurred at wear-induced nascent surfaces or areas of heterogeneous/patchy tribofilm, since most WECs did not breach the contact surface, and those that did only had very small crack volumes for entry of lubricant to have occurred.

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“…In greaselubricated bearings, additives can be locally consumed on the raceways and are hardly replaced. Wan et al [10] have shown that some EP additives can in some cases promote material fatigue and therefore should be used with care in lubricants for rolling element bearings. Many commonly used additives are currently being phased out because of environmental, health and safety aspects.…”

Section: Prevention Of Bearing Surface Damage By Tribological Coatingsmentioning

confidence: 99%

Diamond-like carbon coatings in rolling contacts

Sjöström

Wikström

2001

Proceedings of the Institution of Mechanical Engineers, Part J:

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The use of diamond-like carbon (DLC) coatings to improve the performance of more complex mechanical components or systems is currently increasing rapidly. Higher demands on robustness and reliability and less maintenance imply that incremental improvements in steel or lubricants is no longer sufficient and therefore DLC coatings, belonging to the family of hard wear-resistant coatings, have become a realistic option also for components such as bearings, gears, joints or cams. This paper describes the development of DLC coatings for highly loaded components with complex geometry made from low-temperature stabilized steel, exemplifies their performance with test results and discusses relevant test and quality control methods for component coatings. Finally, an outlook on the future of surface engineering of components is given.

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The Effect of Extreme Pressure (EP) Lubricants on the Life of Rolling Element Bearings

Cited by 8 publications

References 4 publications

The influence of lubricant formulation on early thrust and radial bearing damage associated with white etching cracks

The influence of lubricant formulation on early thrust and radial bearing damage associated with white etching cracks

Thermal Desorption Analysis of Hydrogen in Non-hydrogen-Charged Rolling Contact Fatigue-Tested 100Cr6 Steel

Diamond-like carbon coatings in rolling contacts

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