Article
Engineering, Mechanical
Florian Steinweg, Adrian Mikitisin, Thomas L. M. Janitzky, Silvia Richter, Thomas E. Weirich, Joachim Mayer, Christoph Broeckmann
Summary: It is observed that rolling bearings fail due to the formation of white etching areas and cracks (WEA/WEC). The study focused on the role of specific oil additives and their influence on the formation of reaction layers and WEA/WEC. Comprehensive tests were conducted using two different fully formulated oil lubricants with bearing steel samples. Analysis revealed that an oil formulation containing barium and phosphorus performed well in preventing WEA/WEC damage, while an oil formulation containing zinc dithiophosphate and overbased calcium sulfonate did not result in significant formation of reaction layers.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Ashutosh Panda, Linto Davis, P. Ramkumar, M. Amirthalingam
Summary: The phenomenon of white etching areas (WEAs) in wind turbine gearbox bearings still persists even after more than two decades of research, leading to a 90% reduction in L10 life. Among the various drivers for WEAs formation, hydrogen is considered one of the root causes due to its acceleration of microstructural degradation. This research examines the role of carbide size and volume fraction in their stability against decomposition and hydrogen embrittlement, and finds that reducing carbide size improves their stability against plastic deformation and prevents the formation of WEAs.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
J. Spille, J. Wranik, S. Barteldes, J. Mayer, A. Schwedt, M. Zuercher, T. Lutz, L. Wang, W. Holweger
Summary: This study investigates the formation mechanisms of white etching crack (WEC) failures in drive systems, finding that lubricants can affect the load capacity of steel, leading to the generation of pores and ultimately failure.
Article
Engineering, Mechanical
Martin Linzmayer, Christopher Sous, Francisco Gutierrez Guzman, Georg Jacobs
Summary: White Etching Cracks (WEC) is a damage pattern in roller bearings characterized by sub-surface crack networks. This study focuses on verifying and establishing a test method for assessing the risk of WEC occurrence in predefined tribological systems.
Article
Engineering, Mechanical
Arnaud Ruellan, Kenred Stadler, Jakub Jelita Rydel, Helen Ryan
Summary: The study conducted tests with custom-made lubricants and found that only one oil systematically led to white etching cracks despite similar mechanical stresses caused by both oils. Under mixed lubrication conditions, certain lubricant formulations may affect the bearing steel, particularly in early damage, especially white etching cracks. The paper highlights the importance of using the appropriate test method to validate the understanding and solution to early bearing damage associated with white etching cracks.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Engineering, Mechanical
Fernando Jose Lopez-Urunuela, Beatriz Fernandez-Diaz, Bihotz Pinedo, Josu Aguirrebeitia
Summary: Hydrogen precharged specimens were tested in a disc-on-disc tribometer to study the early stages of crack formation. Small transgranular cracks and unlinked voids were found, as well as premature WEA. This paper aims to clarify certain concepts of debate concerning WEA and proposes a new hypothesis on the mechanism of crack formation.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
Ksenija Nikolic, Vitoria Mattos Ferreira, Loic Malet, Tom Depover, Kim Verbeken, Roumen H. Petrov
Summary: This work characterized the microstructure of a damaged bearing from the field to better understand the microstructural features behind the formation of White Etching Cracks (WEC) in bearings. The microstructural characterization of the altered white etching area (WEA) involved conventional electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), and transmission Kikuchi diffraction (TKD). The results showed that the orientation of detectable grains within WEA is similar to that of the bulk material, and WEA consists of small spherical grains (average 30 nm) with significant variation in grain orientation, indicating recrystallization had occurred.
MATERIALS CHARACTERIZATION
(2023)
Article
Engineering, Mechanical
D. Linto, P. Ramkumar
Summary: Premature bearing failures in extreme conditions are often caused by microstructure decay. This study evaluates the performance of mineral oil and synthetic poly alkyl glycol (PAG) in delaying the formation of white etching areas (WEAs) in bearing steel. The results show that PAG performs better than mineral oil in delaying WEAs formation.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2023)
Article
Engineering, Mechanical
Roger G. Metcalfe, Roger Costanzi, Garry Horner, John Vance
Summary: This paper investigates an unusual pattern of axial fracture in a single row tapered roller bearing and identifies two stages of fracture. It also analyzes the causes of the fracture.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Engineering, Mechanical
Jonathan F. W. Leung, Rohit Voothaluru, Richard W. Neu
Summary: This study introduces a novel Ruiz fretting damage parameter (FDP) implementation to predict the frictional energy dissipation at subsurface cracks, and a parametric study using finite element model explores the role of crack length, orientation, depth, and coefficient of friction (COF) on FDP. The results provide strong evidence of the FDP as a predictor of WEC formation, with specific conditions maximizing the FDP.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Mechanical
Luis Vicente Wilches Pena, Ling Wang, Brian G. Mellor, Yi Huang
Summary: The formation of white etching areas is attributed to severe plastic deformation conditions and the presence of hard discontinuities.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Xiaochen Zhang, Di Wu, Zhuofan Xia, Yaming Zhang, Yifeng Li, Jianqiu Wang, En-Hou Han
Summary: This study investigates the features of White Etching Layer (WEL) and Brown Etching Layer (BEL) found on martensite bearing raceway and discusses the formation mechanisms related to carbon diffusion and redistribution.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Mechanical
Joerg W. H. Franke, Janine Fritz, Thomas Koenig, Daniel Merk
Summary: The tribological contact between raceways and rolling elements in rolling bearings plays a crucial role in their performance and lifetime. While the geometric description of this contact is well-studied and utilized in mechanical simulations, the material description, especially the near-surface volume after interaction with lubricants, is more complex. This research investigates the effect of lubricant chemistry on the failure modes of cylindrical roller thrust bearings in the Schaeffler FE8-25 test, revealing that the lubricant chemistry can influence the failure mechanisms of the test. The characterization of the tribological layers on the raceway was performed using the mu XRF and ATR FTIR microscopy methods, offering new approaches for optimizing rolling bearing testing and predicting early failure risks.
Article
Materials Science, Multidisciplinary
D. Mayweg, L. Morsdorf, X. Wu, M. Herbig
Summary: The white etching crack (WEC) phenomena in high carbon steels affect bearings, and research shows that it is associated with the carbon element. Analyzing the carbon content and distribution in 100Cr6 bearings can provide insights into the formation mechanism of white etching cracks.
Article
Engineering, Mechanical
Xue-Qin Hou, Zheng Zhang, Chang-Kui Liu, Chun-Hu Tao
Summary: This paper investigates the characteristics, formation mechanism, influence on contact fatigue spalling failure, and control methods of white etching area (WEA) in M50 steel bearings. Through analysis of the WEA's location, morphological characteristics, composition analysis, hardness test, and microstructure analysis, it was found that the WEA originates from the boundary between the matrix and primary carbides or inclusions located in the subsurface of the raceway. The WEA exhibits irregular block-shaped morphologies, with a length direction of approximately 30 to 50 degrees relative to the rolling direction and a microstructure of body-centered cubic ferrite nanocrystalline. The formation mechanism of WEA involves phase transformation driven by accumulation of plastic deformation induced by high stress in micro regions. The proximity of the WEA to the raceway surface affects its growth rate, and the poor deformation coordination between the WEA and matrix increases the likelihood of contact fatigue spalling. Controlling the initiation and propagation of WEA can be achieved by reducing material defects and minimizing working stress on the bearings.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Engineering, Mechanical
Joerg Franke, Jim T. Carey, Spyros Korres, Tabassumul Haque, Peter W. Jacobs, Joerg Loos, Wolfram Kruhoeffer
TRIBOLOGY TRANSACTIONS
(2018)
Article
Engineering, Mechanical
Heinrich R. Braun, Spyridon Korres, Peter Laurs, Joerg W. H. Franke
Summary: The increasing electrification of automotive powertrains has led to a reduction in drivetrain fluid viscosities for improved efficiency. However, ultra-low viscosity fluids present new challenges for drivetrain functionality and durability, with the impact varying depending on performance parameters evaluated. By carefully balancing base fluids and additives, acceptable component and fluid durability can be achieved to meet new electric drivetrain performance needs.