Investigation of Microstructural Alterations in Low- and High-Speed Intermediate-Stage Wind Turbine Gearbox Bearings

Singh, Harpal; Pulikollu, Raja V.; Hawkins, Wayne; Smith, Greg

doi:10.1007/s11249-017-0861-5

Cited by 27 publications

(19 citation statements)

References 23 publications

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“…Through metallographic analysis of field-returned WTGBs, it has also been found that small/short sized 8-24 μm MnS inclusions were mainly associated with butterfly/small-WEC crack initiation [22]. Analysis of failed low-speed shaft WTGBs, however, has found that oxide and dual phase inclusions are more detrimental than MnS inclusions [34]. Subsurface WECs and inclusion interactions have also been found through testing and metallographic analysis of WTGBs with induced tensile stresses from bearing seat deviation [27].…”

Section: Introductionmentioning

confidence: 99%

The Evolution of White Etching Cracks (WECs) in Rolling Contact Fatigue-Tested 100Cr6 Steel

et al. 2017

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The formation of white etching cracks (WECs) in steel rolling element bearings can lead to the premature rolling contact fatigue (RCF) failure mode called white structure flaking. Driving mechanisms are still debated but are proposed to be combinations of mechanical, tribochemical and electrical effects. A number of studies have been conducted to record and map WECs in RCF-tested samples and bearings failed from the field. For the first time, this study uses serial sectioning metallography techniques on non-hydrogen charged test samples over a range of test durations to capture the evolution of WEC formation from their initiation to final flaking. Clear evidence for subsurface initiation at non-metallic inclusions was observed at the early stages of WEC formation, and with increasing test duration the propagation of these cracks from the subsurface region to the contact surface eventually causing flaking. In addition, an increase in the amount of associated microstructural changes adjacent to the cracks is observed, this being indicative of the crack being a prerequisite of the microstructural alteration.

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Section: Introductionmentioning

confidence: 99%

The Evolution of White Etching Cracks (WECs) in Rolling Contact Fatigue-Tested 100Cr6 Steel

et al. 2017

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“…Crack is the precondition of WECs [ 1 ], it is the result of cumulative effect caused by cyclic compression load. In the material of wind turbine bearing after service, a butterfly-like microstructure starting from MnS was found [ 39 ]. Cracks frequently appear inside MnS inclusions, some of which produce WEA while others do not [ 37 , 39 ].…”

Section: Resultsmentioning

confidence: 99%

“…In the material of wind turbine bearing after service, a butterfly-like microstructure starting from MnS was found [ 39 ]. Cracks frequently appear inside MnS inclusions, some of which produce WEA while others do not [ 37 , 39 ]. This similar phenomenon has been found in this paper, that is, there is no WEA-associated internal crack in MnS inclusions ( Figure 12 ).…”

Section: Resultsmentioning

confidence: 99%

Preliminary Research on Response of GCr15 Bearing Steel under Cyclic Compression

Xiulin

Zhang

2020

Materials

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During the bearing service, a series of microstructural evolutions will arise inside the material, such as the appearance of feature microstructures. The essential reason for the microstructural evolution is the cumulative effect of cyclic stress. The Hertz Contact formula is usually adopted to calculate the internal stress, and there is a correlation between the shape and distribution of the feature microstructure and the stress distribution. But it is insufficient to explain the relationship between the morphology of feature microstructures and the rolling direction, such as specific angles in butterfly and white etching bands. The rolling phenomenon will cause the asymmetry of stress distribution in the material, which is the source of the rolling friction coefficient. Moreover, slipping or microslip will produce additional stress components, which also cause the asymmetry of the stress field. However, there is no experimental or theoretical explanation for the relationship between the asymmetry of the stress field and the feature microstructure. According to the current theory, the appearance of feature microstructures is caused by stress with or without rolling. Therefore, it is of great significance to study the formation mechanism: whether feature microstructures will appear in the uniaxial cyclic compression stress field without rolling. In this paper, uniaxial cyclic compressive stress was loaded into a plate-ball system and a cylinder system. The characteristics of microstructural change of bearing steel (GCr15) were studied. It was found that the hardness of the material increased after the cyclic compressive load, and the inclusions interacted with the matrix material. In the local microregion a white etching area was found, although the scale is very small. No large-scale feature microstructures appeared. Other phenomena in the experiment are also described and analyzed. For example, the production of oil film in the contact area and the changing law of alternating load.

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“…The formation and morphology of butterflies are strongly linked to the local stress state. The shape, size, rigidity, and distribution of inclusions may change the stress/strain behavior, thus affecting the initiation and evolution of butterflies [6,7]. Following the pioneering observations of butterflies Fig.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on butterfly wings around inclusion based on damage evolution and semi-analytical method

et al. 2021

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Butterfly wings are closely related to the premature failure of rolling element bearings. In this study, butterfly formation is investigated using the developed semi-analytical three-dimensional (3D) contact model incorporating inclusion and material property degradation. The 3D elastic field introduced by inhomogeneous inclusion is solved by using numerical approaches, which include the equivalent inclusion method (EIM) and the conjugate gradient method (CGM). The accumulation of fatigue damage surrounding inclusions is described using continuum damage mechanics. The coupling between the development of the damaged zone and the stress field is considered. The effects of the inclusion properties on the contact status and butterfly formation are discussed in detail. The model provides a potential method for quantifying material defects and fatigue behavior in terms of the deterioration of material properties.

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Investigation of Microstructural Alterations in Low- and High-Speed Intermediate-Stage Wind Turbine Gearbox Bearings

Cited by 27 publications

References 23 publications

The Evolution of White Etching Cracks (WECs) in Rolling Contact Fatigue-Tested 100Cr6 Steel

The Evolution of White Etching Cracks (WECs) in Rolling Contact Fatigue-Tested 100Cr6 Steel

Preliminary Research on Response of GCr15 Bearing Steel under Cyclic Compression

Numerical study on butterfly wings around inclusion based on damage evolution and semi-analytical method

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