formation mechanisms of white etching cracks and

In this study white etching crack reproductions on two different standard endurance test rigs are compared and analyzed in order to firstly propose an update of the understanding of white etching crack surface affected tribochemical formation mechanisms and secondly to identify influent tribochemical and mechanical drivers In this work possible formation mechanisms of squats were investigated based on field and laboratory measurements full-scale wheel-rail test rig experiments and a newly developed simulation tool Wheel-rail contact conditions were found which can lead to cracks in or to outbreaks of a white etching layer (WEL) on a rail surface

Influences on Generation of White Etching Crack

2016-6-1mechanism that is known by the terms WEC (white etching crack) WSF (white structure flaking) or Brittle Flaking [2 3] WECs are networks of cracks at and in white etching phases (Fig 1) which can emerge in both through hardened and case hardened rolling bearings The white etching phases (White Etching

The formation drivers of white etching cracks are contested as are the initiation and propagation mechanisms of the cracks Hydrogen diffusion into bearing steel sourced from the hydrocarbon lubricant or water contamination and transient operating conditions have been suggested as formation drivers

In this work possible formation mechanisms of squats were investigated based on field and laboratory measurements full-scale wheel-rail test rig experiments and a newly developed simulation tool Wheel-rail contact conditions were found which can lead to cracks in or to outbreaks of a white etching layer (WEL) on a rail surface

White Etching Crack formation causes severe microstructure decay during rolling contact fatigue of bearings which drastically reduces their expected service lifetime Starting from non-metallic inclusions crack networks develop below the raceway which eventually reach the raceway surface and lead to catastrophic failure by spalling

Despite constant expansion and engineering progress wind turbines still present unexpected failures of heavy duty mechanical components drastically affecting the cost of energy Among the most prevalent tribological failures in wind turbine rolling element bearings a peculiar rolling contact fatigue mode has been associated to broad subsurface three-dimensional branching crack networks

Investigations of White Etching Crack (WEC) Formation

2019-7-19called white structure flaking (WSF) occurs in wind turbine gearbox bearings WSF can occur in as little as 6-24 months of operation WSF is associated with microstructural altera-tions called white etching area (WEA) and white etching cracks (WECs) that form in

2019-9-22(2014) Formation mechanisms of white etching cracks and white etching area under rolling contact fatigue Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology 228:10 1047-1062 Online publication date: 14-Mar-2014

2017-5-415 Lai J Stadler K : Investigation on the mechanisms of white etching crack (WEC) formation in rolling contact fatigue and identification of a root cause for bearing premature failure Wear 364–365 244–256 (2016) KEYWORDS Wind Turbine Bearings 100Cr6 Steel White Etching Cracks

Hiraoka K Nagao M Isomoto T Study on flaking process in bearings by white etching area generation J ASTM Int 2006 3 1–7 [Google Scholar] Lai J Stadler K Investigation on the mechanisms of white etching cracks (WEC) formation in rolling contact fatigue and identification of a root cause for bearing premature failure

2016-6-1mechanism that is known by the terms WEC (white etching crack) WSF (white structure flaking) or Brittle Flaking [2 3] WECs are networks of cracks at and in white etching phases (Fig 1) which can emerge in both through hardened and case hardened rolling bearings The white etching phases (White Etching

2015-5-25A 2010 368 4829-4850 White structure flaking (WSF) in wind turbine gearbox bearings: effects of 'butterflies' and white etching cracks (WECs) M -H Evans Materials Science and Technology 2012 VOL 28 NO 1 5 WEC Theories Cited Theories of WEC Root Cause

2016-6-1mechanism that is known by the terms WEC (white etching crack) WSF (white structure flaking) or Brittle Flaking [2 3] WECs are networks of cracks at and in white etching phases (Fig 1) which can emerge in both through hardened and case hardened rolling bearings The white etching phases (White Etching

One of the major causes of premature failures of wind turbine gearing systems is the formation of axial cracks in wind turbine bearings Increased surface stress results in increased subsurface stress which in turn leads to a phase change in steel known as white etching areas (WEA)

Threshold Maps for Inclusion

WECs are physical cracks in the material subsurface surrounded by white etching areas (WEAs) Despite considerable evidence [ 19 20 22 23 34 – 38 ] there has been as yet no method devised to prove absolutely that butterfly cracks are indeed the point of damage initiation

Investigation on the mechanisms of white etching crack (WEC) formation in rolling contact fatigue and identification of a root cause for bearing premature failure resulted in the identification of one of the root causes for bearing premature failure characterized by sub-surface 'white etching' cracks (WEC) and surface axial cracks

The formation drivers of white etching cracks are contested as are the initiation and propagation mechanisms of the cracks Hydrogen diffusion into bearing steel sourced from the hydrocarbon lubricant or water contamination and transient operating conditions have been suggested as formation drivers

The formation of white etching cracks in the 1?mm zone beneath the contact surface in steel rolling element bearings causes a premature wear failure mode called white structure flaking The formation drivers of white etching cracks are contested as are the initiation and propagation mechanisms of the cracks Hydrogen diffusion into bearing steel sourced from the hydrocarbon lubricant or water

Ruellan A Ville F Kleber X Understanding white etching cracks in rolling element bearings: The effect of hydrogen charging on the formation mechanisms Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology 2014 228(11): 1252–1265 Google Scholar

2017-5-415 Lai J Stadler K : Investigation on the mechanisms of white etching crack (WEC) formation in rolling contact fatigue and identification of a root cause for bearing premature failure Wear 364–365 244–256 (2016) KEYWORDS Wind Turbine Bearings 100Cr6 Steel White Etching Cracks

2019-11-13White etching cracks (WECs) and the associated white etching areas (WEAs) are responsible for failure of widely spread engineering applications such as bearings and railways Although the phenomenon is known for more than 100 years the underlying mechanisms

Understanding White Etching Cracks (WEC) in rolling element bearings: the effect of hydrogen charging on the formation mechanisms By Arnaud Ruellan Du Crehu Fabrice Ville Xavier Kleber Aurlien Arnaudon and Daniel Girodin Abstract International audienc

2020-7-20White etching cracks (WECs) have been found to form in rolling element bearings as early as 6-24 months into operation especially in large wind turbine gearboxes[1] Despite the number of investigations conducted in both industrial and academic research over the past two to three decades WEC formation and initiation mechanisms are still not well understood

2018-1-23The WEAs are formed by amorphization due to friction at the crack faces during over-rolling These areas appear white under an optical microscope due to their low-etching response to the etchant White etching areas around cracks are 10% to 50% harder than the surrounding unaffected microstructure Causes of white etching crack formation

2016-6-1mechanism that is known by the terms WEC (white etching crack) WSF (white structure flaking) or Brittle Flaking [2 3] WECs are networks of cracks at and in white etching phases (Fig 1) which can emerge in both through hardened and case hardened rolling bearings The white etching phases (White Etching