Tribology Letters

, 62:26 | Cite as

Investigating the Process of White Etching Crack Initiation in Bearing Steel

  • Benjamin GouldEmail author
  • Aaron Greco
Original Paper


White etching cracks (WECs) have been identified as a dominant mode of premature failure within wind turbine gearbox bearings. Though WECs have been reported in the field for over a decade, the conditions leading to WECs and the process by which this failure culminates are both highly debated. In previously published work, the generation of WECs on a benchtop scale was linked to sliding at the surface of the test sample, and it was also postulated that the generation of WECs was dependent on the cumulative energy that had been applied to the sample over the entirety of the test. In this paper, a three-ring-on-roller benchtop test rig is used to systematically alter the cumulative energy that a sample experiences through changes in normal load, sliding, and run-time, in an attempt to correlate cumulative energy with the formation of WECs. It was determined that, in the current test setup, the presence of WECs can be predicted by this energy criterion. The authors then used this information to study the process by which WECs initiate. It was found that, under the current testing conditions, the formation of a dark etching microstructure precedes the formation of a crack, and a crack precedes the formation of white etching microstructure.


White etching cracks Wind turbine gearbox bearings Microstructural alterations Bearing failures 



This work is supported by the US Department of Energy Office of Energy Efficiency and Renewable Energy, Wind and Water Power Technology Office under Contract No. DE-AC02-06CH11357. The authors are grateful to DOE Project Managers Mr. Michael Derby and Mr. Nick Johnson for their support and encouragement. The authors would also like to acknowledge the assistance provided by our colleagues at Argonne National Laboratory’s Tribology Section, especially Dr. Maria De La Cinta Lorenzo Martin for her assistance with electron microscopy and Dr. Oyelayo Ajayi for his helpful discussion on metallurgy. As well as Dr. David L. Burris of the University of Delaware’s department of Mechanical Engineering for serving as an advisor over the course of this work. The authors would also like to thank Dr. Mihails Scepanskis for many useful conversations pertaining to WEC generation and PCS Instruments for providing samples for the MPR testing. Use of the Center for Nanoscale Materials an Office of Science user facility was supported by the US Department of Energy Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357.


  1. 1.
    Kotzalas, M.N., Doll, G.L.: Tribological advancements for reliable wind turbine performance. Philos. Trans. R. Soc. Lond. Math. Phys. Eng. Sci. 368, 4829–4850 (2010)CrossRefGoogle Scholar
  2. 2.
    Musial, W., Butterfield, S., McNiff, B.: Improving wind turbine gearbox reliability. In: European Wind Energy Conference, Milan, Italy. pp. 7–10 (2007)Google Scholar
  3. 3.
    Spinato, F., Tavner, P.J., Van Bussel, G.J.W., Koutoulakos, E.: Reliability of wind turbine subassemblies. IET Renew. Power Gener. 3, 387–401 (2009)CrossRefGoogle Scholar
  4. 4.
    Sheng, S.: Gearbox Reliability Database: Yesterday, Today, and Tomorrow (Presentation). National Renewable Energy Laboratory (NREL), Golden, CO (2014)Google Scholar
  5. 5.
    Grabulov, A., Petrov, R., Zandbergen, H.W.: EBSD investigation of the crack initiation and TEM/FIB analyses of the microstructural changes around the cracks formed under Rolling Contact Fatigue (RCF). Int. J. Fatigue 32, 576–583 (2010)CrossRefGoogle Scholar
  6. 6.
    Harada, H., Mikami, T., Shibata, M., Sokai, D., Yamamoto, A., Tsubakino, H.: Microstructural changes and crack initiation with white etching area formation under rolling/sliding contact in bearing steel. ISIJ Int. 45, 1897–1902 (2005)CrossRefGoogle Scholar
  7. 7.
    Greco, A., Sheng, S., Keller, J., Erdemir, A.: Material wear and fatigue in wind turbine systems. Wear 302, 1583–1591 (2013)CrossRefGoogle Scholar
  8. 8.
    Loos, J., Bergmann, I., Goss, M.: Influence of currents from electrostatic charges on WEC formation in rolling bearings. Tribol. Trans. (2015). doi: 10.1080/10402004.2015.1118582 Google Scholar
  9. 9.
    Kang, J.-H., Hosseinkhani, B., Williams, C.A., Moody, M.P., Bagot, P.A.J., Rivera-Díaz-del-Castillo, P.E.J.: Solute redistribution in the nanocrystalline structure formed in bearing steels. Scr. Mater. 69, 630–633 (2013)CrossRefGoogle Scholar
  10. 10.
    Gould, B., Greco, A.: The influence of sliding and contact severity on the generation of white etching cracks. Tribol. Lett. 60, 1–13 (2015)CrossRefGoogle Scholar
  11. 11.
    Becker, P.C.: Microstructural changes around non-metallic inclusions caused by rolling-contact fatigue of ball-bearing steels. Met. Technol. 8, 234–243 (1981)CrossRefGoogle Scholar
  12. 12.
    Gegner, J.: Tribological Aspects of Rolling Bearing Failures. INTECH Open Access Publisher (2011)Google Scholar
  13. 13.
    Uyama, H., Yamada, H., Hidaka, H., Mitamura, N.: The effects of hydrogen on microstructural change and surface originated flaking in rolling contact fatigue. Tribol. Online 6, 123–132 (2011)CrossRefGoogle Scholar
  14. 14.
    Swahn, H., Becker, P.C., Vingsbo, O.: Martensite decay during rolling contact fatigue in ball bearings. Metall. Trans. A 7, 1099–1110 (1976)CrossRefGoogle Scholar
  15. 15.
    Österlund, R., Vingsbo, O.: Phase changes in fatigued ball bearings. Metall. Trans. A 11, 701–707 (1980)CrossRefGoogle Scholar
  16. 16.
    Mitamura, N., Hidaka, H., Takaki, S.: Microstructural development in bearing steel during rolling contact fatigue. In: Materials science forum. pp. 4255–4260. Trans Tech Publications (2007)Google Scholar
  17. 17.
    Hershberger, J., Ajayi, O.O., Zhang, J., Yoon, H., Fenske, G.R.: Evidence of scuffing initiation by adiabatic shear instability. Wear 258, 1471–1478 (2005)CrossRefGoogle Scholar
  18. 18.
    Torrance, A.A., Cameron, A.: Surface transformations in scuffing. Wear 28, 299–311 (1974)CrossRefGoogle Scholar
  19. 19.
    Oila, A., Bull, S.J.: Phase transformations associated with micropitting in rolling/sliding contacts. J. Mater. Sci. 40, 4767–4774 (2005)CrossRefGoogle Scholar
  20. 20.
    Robinski, J., Smurthwaite, D.: Troubleshooting wind gearbox problems. Gear Solut. 8, 22–33 (2010)Google Scholar
  21. 21.
    Kang, Y.S., Evans, R.D., Doll, G.L.: Roller-raceway slip simulations of wind turbine gearbox bearings using dynamic bearing model. In: STLE/ASME 2010 International Joint Tribology Conference. pp. 407–409. American Society of Mechanical Engineers (2010)Google Scholar
  22. 22.
    Grabulov, A., Ziese, U., Zandbergen, H.W.: TEM/SEM investigation of microstructural changes within the white etching area under rolling contact fatigue and 3-D crack reconstruction by focused ion beam. Scr. Mater. 57, 635–638 (2007)CrossRefGoogle Scholar
  23. 23.
    Ciruna, J.A., Szieleit, H.J.: The effect of hydrogen on the rolling contact fatigue life of AISI 52100 and 440C steel balls. Wear 24, 107–118 (1973)CrossRefGoogle Scholar
  24. 24.
    Grunberg, L.: The formation of hydrogen peroxide on fresh metal surfaces. Proc. Phys. Soc. Sect. B 66, 153 (1953)CrossRefGoogle Scholar
  25. 25.
    Imran, T., Jacobson, B., Shariff, A.: Quantifying diffused hydrogen in AISI-52100 bearing steel and in silver steel under tribo-mechanical action: pure rotating bending, sliding–rotating bending, rolling–rotating bending and uni-axial tensile loading. Wear 261, 86–95 (2006)CrossRefGoogle Scholar
  26. 26.
    Iso, K., Yokouchi, A., Takemura, H.: Research work for clarifying the mechanism of white structure flaking and extending the life of bearings. SAE Technical Paper (2005)Google Scholar
  27. 27.
    Vegter, R.H., Slycke, J.T.: The role of hydrogen on rolling contact fatigue response of rolling element bearings. J. ASTM Int. 7, 1–12 (2009)Google Scholar
  28. 28.
    Hiraoka, K., Fujimatsu, T., Tsunekage, N., Yamamoto, A.: Generation process observation of micro-structural change in rolling contact fatigue by hydrogen-charged specimens. J. Jpn. Soc. Tribol. 52, 888–895 (2007)Google Scholar
  29. 29.
    Kino, N., Otani, K.: The influence of hydrogen on rolling contact fatigue life and its improvement. JSAE Rev. 24, 289–294 (2003)CrossRefGoogle Scholar
  30. 30.
    Tamada, K., Tanaka, H.: Occurrence of brittle flaking on bearings used for automotive electrical instruments and auxiliary devices. Wear 199, 245–252 (1996)CrossRefGoogle Scholar
  31. 31.
    Ray, D., Vincent, L., Coquillet, B., Guirandenq, P., Chene, J., Aucouturier, M.: Hydrogen embrittlement of a stainless ball bearing steel. Wear 65, 103–111 (1980)CrossRefGoogle Scholar
  32. 32.
    Matsubara, Y., Hamada, H.: A novel method to evaluate the influence of hydrogen on fatigue properties of high strength steels. J. ASTM Int. 3, 1–14 (2006)CrossRefGoogle Scholar
  33. 33.
    Lü, H., Li, M., Zhang, T., Chu, W.: Hydrogen-enhanced dislocation emission, motion and nucleation of hydrogen-induced cracking for steel. Sci. China Ser. E: Technol. Sci. 40, 530–538 (1997)CrossRefGoogle Scholar
  34. 34.
    Fujita, S., Matsuoka, S., Murakami, Y., Marquis, G.: Effect of hydrogen on mode II fatigue crack behavior of tempered bearing steel and microstructural changes. Int. J. Fatigue 32, 943–951 (2010)CrossRefGoogle Scholar
  35. 35.
    Evans, M.-H., Richardson, A.D., Wang, L., Wood, R.J.K.: Effect of hydrogen on butterfly and white etching crack (WEC) formation under rolling contact fatigue (RCF). Wear 306, 226–241 (2013)CrossRefGoogle Scholar
  36. 36.
    Ruellan, A., Ville, F., Kleber, X., Arnaudon, A., Girodin, D.: Understanding white etching cracks in rolling element bearings: the effect of hydrogen charging on the formation mechanisms. Proc. Inst. Mech. Eng. Part J J. Eng. Tribol. 228, 1252–1265 (2014)CrossRefGoogle Scholar
  37. 37.
    Evans, M.-H., Wang, L., Jones, H., Wood, R.J.K.: White etching crack (WEC) investigation by serial sectioning, focused ion beam and 3-D crack modelling. Tribol. Int. 65, 146–160 (2013)CrossRefGoogle Scholar
  38. 38.
    Holweger, W., Wolf, M., Merk, D., Blass, T., Goss, M., Loos, J., Barteldes, S., Jakovics, A.: White etching crack root cause investigations. Tribol. Trans. 58, 59–69 (2015)CrossRefGoogle Scholar
  39. 39.
    Evans, M.-H., Richardson, A.D., Wang, L., Wood, R.J.K., Anderson, W.B.: Confirming subsurface initiation at non-metallic inclusions as one mechanism for white etching crack (WEC) formation. Tribol. Int. 75, 87–97 (2014)CrossRefGoogle Scholar
  40. 40.
    Evans, M.-H., Richardson, A.D., Wang, L., Wood, R.J.K.: Serial sectioning investigation of butterfly and white etching crack (WEC) formation in wind turbine gearbox bearings. Wear 302, 1573–1582 (2013)CrossRefGoogle Scholar
  41. 41.
    Leslie, W.: The Physical Metallurgy of Steels. Hemisphere Publishing Corporation, Mcgraw-Hill Book Company, Washington, New York, London (1981)Google Scholar
  42. 42.
    Hernandez, V.B., Nayak, S.S., Zhou, Y.: Tempering of martensite in dual-phase steels and its effects on softening behavior. Metall. Mater. Trans. A 42, 3115–3129 (2011)CrossRefGoogle Scholar
  43. 43.
    Evans, M.-H., Walker, J.C., Ma, C., Wang, L., Wood, R.J.K.: A FIB/TEM study of butterfly crack formation and white etching area (WEA) microstructural changes under rolling contact fatigue in 100Cr6 bearing steel. Mater. Sci. Eng. A 570, 127–134 (2013)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York (outside the USA) 2016

Authors and Affiliations

  1. 1.Energy Systems DivisionArgonne National LaboratoryLemontUSA
  2. 2.Department of Mechanical EngineeringUniversity of DelawareNewarkUSA

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