Research Work for Clarifying the Mechanism of White Structure Flaking and Extending the Life of Bearings

Iso, K.; Yokouchi, Atsushi; Takemura, Hiroyuki

doi:10.4271/2005-01-1868

Cited by 51 publications

(50 citation statements)

References 2 publications

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“…Some of them suggest that hydrogen embrittlement is not due to brittle fracture 2,[6][7][8] , for example, Birnbaum and Sofronis 6) showed that hydrogen enhances localized plasticity and Nagumo et al 8) suggested that hydrogen increases atomic vacancies and causes unstable plasticity. In the case of rolling contact fatigue, there are some studies that have suggested that hydrogen generated by the decomposition of lubricant or water in the lubricant decreases the rolling contact fatigue life [9][10][11][12][13][14][15][16][17][18] . Some of them pointed that hydrogen causes microstructural change called white structure or white etching area (WEA) [15][16][17][18] .…”

Section: Introductionmentioning

confidence: 99%

“…In the case of rolling contact fatigue, there are some studies that have suggested that hydrogen generated by the decomposition of lubricant or water in the lubricant decreases the rolling contact fatigue life [9][10][11][12][13][14][15][16][17][18] . Some of them pointed that hydrogen causes microstructural change called white structure or white etching area (WEA) [15][16][17][18] . It suggested that types of lubricant, slip between rolling elements and rings, and static electricity affect hydrogen generation and diffusion into bearing steels.…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue

et al. 2011

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The effects of hydrogen on microstructural change and surface originated flaking in rolling contact fatigue were investigated using JIS-SUJ2 bearing steel specimens charged with hydrogen. Under clean lubrication conditions, subsurface originated flaking occurred and the rolling contact fatigue life was reduced and the amounts of the microstructural change called white structure that formed in the specimens increased as the hydrogen content increased. The localized microstructural changes were found in the hydrogen-charged specimens by electron microscope observations. It is supposed that the localization of plasticity was enhanced by hydrogen during the process of rolling contact fatigue. Under contaminated lubrication conditions, which included debris in the lubricating oil, surface originated flaking occurred and the rolling contact fatigue life of the hydrogen-charged specimens became shorter than the uncharged specimens, although white structure was not observed around the flaking. Enhancement of fatigue crack formations due to hydrogen was observed in specimens with artificial dents. It is presumed that hydrogen facilitated the formation of fatigue cracks on the raceway surface.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue

et al. 2011

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“…The selection of anti-corrosion protection [25] and the presence of water [26] can also have a decisive influence on the tendency towards WEC.…”

Section: The Influence Of Lubricantmentioning

confidence: 99%

Influences on Generation of White Etching Crack Networks in Rolling Bearings

Loos¹,

Blass²,

Franke³

et al. 2016

JMEA

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Abstract:In rare cases rolling bearings fail by WEC (white etching crack) damage before reaching their calculated rating life, if so called additional loads are applied on the bearing in addition to the normal Hertzian stress (p Hz ). A number of additional loads have been identified by means of tests with rolling bearings. These can be small direct currents as a result of electrostatic charge or large alternating currents from inverter-fed drives that unintentionally flow through the bearing. WEC damages can also be initiated by a pure mechanical additional load which is dependent on factors including the bearing kinematics but also on the dynamics of the drive train. The current state of knowledge on this subject is presented and taken as the basis for developing a hypothesis on the WEC damage mechanism. If load situations critical for WEC cannot be avoided, the risk of WEC can be considerably reduced by the selection of suitable materials and coatings as well as, in some cases, of suitable lubricants.

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“…Grease lubrication depends on grease components including base oils, their viscosity, thickeners and their concentration, which are chosen to meet lubricating performances required [1][2][3][4] . Structure of thickeners is one of the most important factors that affect physical properties and resulting frictional behaviors of greases.…”

Section: Overviewmentioning

confidence: 99%

Effects of Soap Fiber Structure on Boundary Lubrication of Lithium Soap Greases

2011

Self Cite

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This paper describes the influence of fiber length of lithium-soap thickener of greases on friction under boundary lubrication conditions. Ball-on-disk sliding tests were conducted with lithium soap greases with polyol ester as the base oil. The tests revealed that the greases had a lower friction coefficient than that for the base oil. The grease with a long soap fiber structure had a lower friction coefficient than that for the grease with a short soap fiber structure. The tests with only soap fibers showed that the soap fibers had better lubricity than the base oil under the boundary conditions tested, but there was little difference in the lubricity of the longer fibers and the shorter fibers. The partial coat tests revealed that the grease with longer soap fibers was easily entrained into the contact. It was concluded that this entrainment capability of the grease led to favorable lubrication to maintain low friction coefficient.

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Research Work for Clarifying the Mechanism of White Structure Flaking and Extending the Life of Bearings

Cited by 51 publications

References 2 publications

The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue

The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue

Influences on Generation of White Etching Crack Networks in Rolling Bearings

Effects of Soap Fiber Structure on Boundary Lubrication of Lithium Soap Greases

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