An updated review: white etching cracks (WECs) and axial cracks in wind turbine gearbox bearings

The actual service life of wind turbine gearboxes is often well below the desired 20 years. One of the prevalent failure modes in gearbox bearing raceways is white structure flaking (WSF) in as little as 6–24 months of operation by the formation of axial cracks and white etching cracks (WECs) with associated microstructural change called white etching areas (WEAs). Despite these failures having been observed for two decades in various industries, the drivers and mechanisms for their formation are still highly contested. Discussed in this review are methods for searching and analysing WECs, mechanisms for WEA microstructural change, WEC initiation and propagation theories, WSF formation drivers and finally technologies and processes offering resistance to WSF. This updated review serves as a recap, comprehensive update on findings, current focus areas and remaining challenges. This paper is part of a Themed Issue on Recent developments in bearing steels.

[1]  J. Ćwiek Hydrogen degradation of high-strength steels , 2009 .

[2]  J. Gegner,et al.  Tribological Aspects of Rolling Bearing Failures , 2011 .

[3]  N. Winzer,et al.  Hydrogen diffusion and trapping in bodies undergoing rolling contact , 2013 .

[4]  E. Streit,et al.  Progress in bearing performance of advanced nitrogen alloyed stainless steel, cronidur 30 , 1999 .

[5]  A. Paxton,et al.  Hydrogen embrittlement I. Analysis of hydrogen-enhanced localized plasticity: Effect of hydrogen on the velocity of screw dislocations in α -Fe , 2017 .

[6]  K. Hiraoka,et al.  Effect of inclusion/matrix interface cavities on internal-fracture-type rolling contact fatigue life , 2011 .

[7]  Paul Schatzberg,et al.  Inhibition of Water-Accelerated Rolling-Contact Fatigue , 1971 .

[8]  M.-H. Evans,et al.  Confirming subsurface initiation at non-metallic inclusions as one mechanism for white etching crack (WEC) formation , 2014 .

[9]  J. Luyckx White Etching Crack Failure Mode in Roller Bearings: From Observation via Analysis to Understanding and an Industrial Solution , 2012 .

[10]  Jee-Hyun Kang Mechanisms of microstructural damage during rolling contact fatigue of bearing steels , 2014 .

[11]  Farshid Sadeghi,et al.  A Damage Mechanics Approach to Simulate Butterfly Wing Formation Around Nonmetallic Inclusions , 2015 .

[12]  Y. Yamamoto,et al.  Study on Rolling Contact Fatigue in Hydrogen Atmosphere - Improvement of Rolling Contact Fatigue Life by Formation of Surface Film - , 2005 .

[13]  Micropitting Performance of Oil Additives in Lubricated Rolling Contacts , 2013 .

[14]  J. A. Martin,et al.  Microstructural Alterations of Rolling—Bearing Steel Undergoing Cyclic Stressing , 1966 .

[15]  Peter Tavner,et al.  Bearing currents in wind turbine generators , 2013 .

[16]  M. Bacher-Höchst,et al.  Very high cycle fatigue properties of bainitic high carbon―chromium steel under variable amplitude conditions , 2009 .

[17]  P. Rivera-Díaz-del-Castillo,et al.  Carbide dissolution in bearing steels , 2013 .

[18]  P. Bagot,et al.  Solute redistribution in the nanocrystalline structure formed in bearing steels , 2013 .

[19]  H. Zandbergen,et al.  TEM/SEM investigation of microstructural changes within the white etching area under rolling contact fatigue and 3-D crack reconstruction by focused ion beam , 2007 .

[20]  Gary L. Doll,et al.  Influence of Steel Type on the Propensity for Tribochemical Wear in Boundary Lubrication with a Wind Turbine Gear Oil , 2010 .

[21]  B Tomkins,et al.  A fracture mechanics interpretation of rolling bearing fatigue , 2012 .

[22]  R. E. Cantley,et al.  The Effect of Water in Lubricating Oil on Bearing Fatigue Life , 1977 .

[23]  Takayuki Kawamura,et al.  Study on Mechanism of Hydrogen Generation from Lubricants , 2006 .

[24]  Rob Dwyer-Joyce,et al.  Dynamic modelling of wind turbine gearbox bearing loading during transient events , 2015 .

[25]  Kazuya Hashimoto,et al.  Study of rolling contact fatigue of bearing steels in relation to various oxide inclusions , 2011 .

[26]  A. Jakovics,et al.  White Etching Crack Root Cause Investigations , 2015 .

[27]  Petros Athanasios Sofronis,et al.  Hydrogen-enhanced localized plasticity—a mechanism for hydrogen-related fracture , 1993 .

[28]  Paper 10: Metallurgical Aspects of Rolling Contact Fatigue: , 1966 .

[29]  A Novel Method to Evaluate the Influence of Hydrogen on Fatigue Properties of High Strength Steels , 2006 .

[30]  A. P. Voskamp,et al.  Gradual changes in residual stress and microstructure during contact fatigue in ball bearings , 1980 .

[31]  F. B. Oswald,et al.  Interference-Fit Life Factors for Ball Bearings , 2010 .

[32]  L. Grunberg,et al.  Hydrogen penetration in water-accelerated fatigue of rolling surfaces , 1963 .

[33]  Externer Artikel,et al.  Fatigue Load Computation of Wind Turbine Gearboxes by Coupled Structural, Mechanism and Aerodynamic Analysis , 2006 .

[34]  A. P. Voskamp Material Response to Rolling Contact Loading , 1985 .

[35]  K. Stadler,et al.  A Review: The Dilemma With Premature White Etching Crack (WEC) Bearing Failures , 2015 .

[37]  Arnaud Ruellan Du Crehu Tribological analysis of White Etching Crack (WEC) failures in rolling element bearings : Analyse tribologique des défaillances de roulements par fatigue de contact de type White Etching Cracks (WEC) , 2014 .

[38]  Michael N Kotzalas,et al.  Tribological advancements for reliable wind turbine performance , 2010, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[39]  M.-H. Evans,et al.  Formation mechanisms of white etching cracks and white etching area under rolling contact fatigue , 2014 .

[40]  P. Perzyna,et al.  The Physics and Mathematics of Adiabatic Shear Bands , 2002 .

[41]  Jo Wolfe,et al.  Clean Engineered Steels - Progress at the End of the Twentieth Century , 1999 .

[43]  S. W. Dean,et al.  Sub-Surface Initiated Rolling Contact Fatigue—Influence of Non-Metallic Inclusions, Processing History, and Operating Conditions , 2010 .

[44]  Jürgen Gegner,et al.  Service Loading Analysis of Wind Turbine Gearbox Rolling Bearings Based on X-Ray Diffraction Residual Stress Measurements , 2013 .

[45]  M. Sugisaki,et al.  Observation of Hydrogen Distribution around Non-Metallic Inclusions in Steels with Tritium Microautoradiography , 2005 .

[46]  K. Hiraoka,et al.  Study on Flaking Process in Bearings by White Etching Area Generation , 2006 .

[47]  A. Fazekas,et al.  A new methodology based on X-ray micro-tomography to estimate stress concentrations around inclusions in high strength steels , 2009 .

[48]  Gary L. Doll,et al.  Roller-Raceway Slip Simulations of Wind Turbine Gearbox Bearings Using Dynamic Bearing Model , 2010 .

[49]  Hisashi Harada,et al.  Microstructural Changes and Crack Initiation with White Etching Area Formation under Rolling/Sliding Contact in Bearing Steel , 2005 .

[50]  W. Nierlich,et al.  S136 Operational Residual Stress Formation in Vibration-Loaded Rolling Contact , 2008, Powder Diffraction.

[51]  Fabrice Ville,et al.  Understanding white etching cracks in rolling element bearings: The effect of hydrogen charging on the formation mechanisms , 2014 .

[52]  Nobuo Kino,et al.  The influence of hydrogen on rolling contact fatigue life and its improvement , 2003 .

[53]  R. A. Oriani,et al.  The hydrogen permeation through passivating film on iron by modulation method , 1991 .

[54]  Yasuo Murakami,et al.  Long Life Bearings for Automotive Alternator Applications , 1995 .

[55]  E Schreiber,et al.  Effects of Material Properties on Bearing Steel Fatigue Strength , 1988 .

[56]  T. E. Tallian,et al.  Ball bearing lubrication: The elastohydrodynamics of elliptical contacts , 1982 .

[57]  M. Shibata Trends of Studies on Rolling Contact Fatigue Life and Recent Results , 2004 .

[58]  Hiromichi Takemura,et al.  Research Work for Clarifying the Mechanism of White Structure Flaking and Extending the Life of Bearings , 2005 .

[59]  Hiroyasu Saka,et al.  Analysis of rolling contact fatigued microstructure using focused ion beam sputtering and transmission electron microscopy observation , 1995 .

[60]  Robert J.K. Wood,et al.  Effect of hydrogen on butterfly and white etching crack (WEC) formation under rolling contact fatigue (RCF) , 2013 .

[61]  Hui Long,et al.  Characterisation of white etching crack damage in wind turbine gearbox bearings , 2015 .

[62]  M. Nakamura,et al.  Hydrogen thermal desorption relevant to delayed-fracture susceptibility of high-strength steels , 2001 .

[63]  B. Gould,et al.  The Influence of Sliding and Contact Severity on the Generation of White Etching Cracks , 2015, Tribology Letters.

[64]  Henry Peredur Evans,et al.  Elastohydrodynamic Lubrication Analysis of Gear Tooth Surfaces From Micropitting Tests , 2003 .

[65]  Shuangwen Sheng,et al.  Material Wear and Fatigue in Wind Turbine Systems , 2013 .

[66]  S. Suresh Fatigue of materials , 1991 .

[67]  J. Sullivan,et al.  The Pitting and Cracking of SAE 52100 Steel in Rolling/Sliding Contact in the Presence of an Aqueous Lubricant , 1985 .

[69]  M. Mauntz,et al.  A Sensor System for Online Oil Condition Monitoring of Operating Components , 2013 .

[70]  Markus Dinkel,et al.  Effect of non-metallic inclusions on butterfly wing initiation, crack formation, and spall geometry in bearing steels , 2015 .

[71]  Yukitaka Murakami,et al.  The effect of hydrogen on fatigue properties of steels used for fuel cell system , 2006 .

[72]  Gregory N. Haidemenopoulos,et al.  STEELS FOR BEARINGS , 2016 .

[73]  Fred B. Oswald,et al.  Interference-Fit Life Factors for Roller Bearings , 2009 .

[74]  J. Hirth,et al.  Effects of hydrogen on the properties of iron and steel , 1980 .

[75]  Kevin Barraclough,et al.  I and i , 2001, BMJ : British Medical Journal.

[76]  M. Grujicic,et al.  Wind-Turbine Gear-Box Roller-Bearing Premature-Failure Caused by Grain-Boundary Hydrogen Embrittlement: A Multi-physics Computational Investigation , 2014, Journal of Materials Engineering and Performance.

[77]  Pedro E.J. Rivera-Díaz-del-Castillo,et al.  Unveiling the nature of hydrogen embrittlement in bearing steels employing a new technique , 2013 .

[78]  R. A. Oriani Whitney Award Lecture—1987: Hydrogen—The Versatile Embrittler , 1987 .

[79]  O. Zwirlein,et al.  Rolling Contact Fatigue Mechanisms—Accelerated Testing Versus Field Performance , 1982 .

[80]  I. M. Felsen,et al.  Effects of water and oxygen during rolling contact lubrication , 1968 .

[81]  Y. Radovcic,et al.  Fatigue Load Computation of Wind Turbine Gearboxes by Coupled Structural , Mechanism and Aerodynamic Analysis , 2006 .

[82]  A. Olver The Mechanism of Rolling Contact Fatigue: An Update , 2005 .

[83]  O. Umezawa,et al.  Effects of test temperature on internal fatigue crack generation associated with nonmetallic particles in austenitic steels , 1998 .

[84]  Rolling Contact Fatigue Under Water-Infiltrated Lubrication , 2002 .

[85]  E. J. Mittemeijer,et al.  State of residual stress induced by cyclic rolling contact loading , 1997 .

[86]  Roumen Petrov,et al.  EBSD investigation of the crack initiation and TEM/FIB analyses of the microstructural changes around the cracks formed under Rolling Contact Fatigue (RCF) , 2010 .

[87]  H. Bhadeshia,et al.  White-Etching Matter in Bearing Steel. Part II: Distinguishing Cause and Effect in Bearing Steel Failure , 2014, Metallurgical and Materials Transactions A.

[89]  R. Vegter,et al.  The Role of Hydrogen on Rolling Contact Fatigue Response of Rolling Element Bearings , 2010 .

[90]  M.-H. Evans White structure flaking (WSF) in wind turbine gearbox bearings: effects of ‘butterflies’ and white etching cracks (WECs) , 2012 .

[91]  Robert J.K. Wood,et al.  A FIB/TEM study of butterfly crack formation and white etching area (WEA) microstructural changes under rolling contact fatigue in 100Cr6 bearing steel , 2013 .

[92]  A. Bahaj,et al.  Tribological design constraints of marine renewable energy systems , 2010, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[93]  James V. Beck,et al.  Using Directional Flame Thermometers for Measuring Thermal Exposure , 2010 .

[94]  D. Olson,et al.  Retained austenite as a hydrogen trap in steel welds , 2002 .

[95]  Arno Stubenrauch,et al.  Premature Bearing Failures in Wind Gearboxes and White Etching Cracks , 2014 .

[96]  Jarek Rosinski,et al.  Troubleshooting Wind Gearbox Problems A , 2010 .

[97]  H. Bhadeshia,et al.  Critical Assessment 13: Elimination of white etching matter in bearing steels , 2015 .

[98]  J. Sugimura,et al.  Observation of Hydrogen Permeation into Fresh Bearing Steel Surface by Thermal Desorption Spectroscopy , 2011 .

[99]  M.-H. Evans,et al.  Serial sectioning investigation of butterfly and white etching crack (WEC) formation in wind turbine gearbox bearings , 2013 .

[100]  D. Hirakami,et al.  Thermal Desorption Analysis of Hydrogen in High Strength Martensitic Steels , 2012, Metallurgical and Materials Transactions A.

[102]  H. Walton The Influence of Residual Stresses on the Susceptibility to Hydrogen Embrittlement in Hardened Steel Components Subjected to Rolling Contact Conditions , 2002 .

[103]  Electron microscopy analysis of structural changes within white etching areas , 2016 .

[104]  T. Kawamura,et al.  Influence of Electrical Current on Bearing Flaking Life , 2007 .

[105]  S. Nishida,et al.  Cementite decomposition in heavily drawn pearlite steel wire , 2001 .

[106]  W. Marsden I and J , 2012 .

[107]  H. Johnson Hydrogen embrittlement. , 1973, Science.

[108]  R. Fougères,et al.  From White Etching Areas Formed Around Inclusions to Crack Nucleation in Bearing Steels Under Rolling Contact Fatigue , 1998 .

[109]  Robert J.K. Wood,et al.  White etching crack (WEC) investigation by serial sectioning, focused ion beam and 3-D crack modelling , 2013 .

[110]  M. Nagumo Hydrogen related failure of steels – a new aspect , 2004 .

[111]  Nobuaki Mitamura,et al.  The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue , 2011 .

[112]  Trevor S. Slack,et al.  A Review of Rolling Contact Fatigue , 2009 .

[113]  S. Walley Shear Localization: A Historical Overview , 2007 .

[114]  Peder Klit,et al.  Observations of the effect of varying Hoop stress on fatigue failure and the formation of white etching areas in hydrogen infused 100Cr6 steel rings , 2015 .

[115]  Jürgen Gegner,et al.  Evidence and analysis of thermal static strain aging in the deformed surface zone of finish-machined hardened steel , 2009, Powder Diffraction.

[116]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[117]  D. Suh,et al.  Cracks in Martensite Plates as Hydrogen Traps in a Bearing Steel , 2015, Metallurgical and Materials Transactions A.

[118]  H. Bhadeshia,et al.  Bearing steel microstructures after aircraft gas turbine engine service , 2014 .

[119]  John L. O'Brien,et al.  Electron Microscopy of Stress-Induced Structural Alterations Near Inclusions in Bearing Steels , 1966 .

[120]  T. V. Liston,et al.  Engine lubricant additives what they are and how they function , 1992 .

[121]  Application of Complementary Techniques for Advanced Characterization of White Etching Cracks , 2013 .

[122]  G. Pressouyre A classification of hydrogen traps in steel , 1979 .

[123]  I. Bernstein,et al.  The Role of Metallurgical Variables in Hydrogen-Assisted Environmental Fracture , 1980 .

[124]  M. Nagumo,et al.  Structural Alterations of Bearing Steels under Rolling Contact Fatigue , 1970 .

[125]  Ervin Bossanyi,et al.  Wind Energy Handbook , 2001 .

[126]  Fundamentals of Rolling Contact Fatigue , 2010 .

[127]  P. C. Becker Microstructural changes around non-metallic inclusions caused by rolling-contact fatigue of ball-bearing steels , 1981 .

[128]  Yukitaka Murakami,et al.  Hydrogen Embrittlement Mechanism in Fatigue of Austenitic Stainless Steels , 2008 .

[129]  J. A. Ciruna,et al.  The effect of hydrogen on the rolling contact fatigue life of AISI 52100 and 440C steel balls , 1973 .

[130]  K. Tamada,et al.  Occurrence of brittle flaking on bearings used for automotive electrical instruments and auxiliary devices , 1996 .

[131]  Gary Marquis,et al.  Effect of hydrogen on Mode II fatigue crack behavior of tempered bearing steel and microstructural changes , 2010 .

[132]  M. Nagumo,et al.  Lattice defects dominating hydrogen-related failure of metals , 2008 .

[133]  M.-H. Evans White structure flaking failure in bearings under rolling contact fatigue , 2013 .

[134]  Ap Voskamp,et al.  Fatigue and Material Response in Rolling Contact , 1998 .

[135]  P. Rivera-Díaz-del-Castillo,et al.  Developing bearing steels combining hydrogen resistance and improved hardness , 2013 .

[136]  Robert Errichello,et al.  Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes , 2013 .

[137]  R. A. Oriani,et al.  HYDROGEN - THE VERSATILE EMBRITTLER , 1987 .

[138]  Mica Grujicic,et al.  Multiphysics computational analysis of white-etch cracking failure mode in wind turbine gearbox bearings , 2016 .

[139]  D. Brooksbank,et al.  STRESS FIELDS AROUND INCLUSIONS AND THEIR RELATION TO MECHANICAL PROPERTIES , 1972 .