Influence of Solid Contaminants on the Fatigue Life of Lubricated Machine Elements

Author(s):  
F Ville ◽  
S Coulon ◽  
A. A. Lubrecht

Solid contamination of lubricants is one of the main causes of premature rolling contact fatigue of machine elements (e.g. rolling element bearings in automotive gearboxes). Understanding the indentation process (creation of surface defect by debris passing through the contact) and the surface damage initiation allows the prediction of the induced risk. This article summarizes the work of the authors and proposes a risk prediction on the basis of operating conditions and dent geometry.

2005 ◽  
Vol 127 (3) ◽  
pp. 611-622 ◽  
Author(s):  
D. Nélias ◽  
C. Jacq ◽  
G. Lormand ◽  
G. Dudragne ◽  
A. Vincent

A new methodology is proposed to evaluate the rolling contact fatigue (RCF) performance of bearing steels in presence of surface dents. The experimental procedure consists of denting the raceway of test specimens with a hardness machine using spherical diamond tips of different radii (i.e., 200, 400, and 600μm) and with an applied normal load ranging from 5to50daN. Analysis of various dent geometries yield an analytical law with five parameters useful for fitting experimental profiles for contact simulation. Fatigue tests are conducted using a two-disk machine to study the effect of different operating conditions on RCF and to compare the performances of nitrided 32CrMoV13 steel versus M50 reference steel. A numerical investigation is conducted to analyze experimental result. Initially, the local residual stresses and plastic strains around the dent are obtained through finite element simulations of the indentation process. Second, the overrolling of the dent is simulated with a contact code. Finally, an indent-based endurance limit, called H1I, is proposed and comparisons are made with test results. Both RCF tests and numerical simulations show improved performance with nitrided 32CrMoV13 steel when compared to the M50 reference steel. The dominating role of sliding is also experimentally highlighted and two areas of damage initiation are identified. The effects of normal load and hoop stress are less marked.


1999 ◽  
Vol 121 (2) ◽  
pp. 240-251 ◽  
Author(s):  
D. Ne´lias ◽  
M. L Dumont ◽  
F. Champiot ◽  
A. Vincent ◽  
D. Girodin ◽  
...  

Tests have been performed on a two-disk machine in order to evaluate the role of inclusions, surface roughness and operating conditions on rolling contact fatigue of AISI 52100 and M50 bearing steels. Important parameters—such as nature and location of inclusions, small and large wavelengths of surface roughness, normal loading or sliding conditions—on crack initiation and propagation stages have been identified. The operating conditions have been selected to encompass typical jet engine applications. Tests have been carried out up to 4.2 GPa, for two different surface finishes. Surface distress and sub-surface damage which could result in catastrophic failure have been observed. Indeed, surface initiated deep spalling (observed at 3.5 GPa for unpolished surfaces and under rolling plus sliding conditions) as well as sub-surface initiated deep spalling (at 4.2 GPa for polished specimens) have been observed. Sub-surface micro-cracks were detected early and followed during some interrupted tests by the means of an ultrasonic echographic device. Results of our experiments are analyzed and discussed in relation to the rolling contact fatigue theories.


2019 ◽  
Vol 300 ◽  
pp. 06002
Author(s):  
Hamidreza Mahdavi ◽  
Konstantinos Poulios ◽  
Christian F. Niordson

A theoretical framework is developed for the evaluation of favorable residual stress profiles, suppressing fatigue damage initiation in rolling contact fatigue. Non-metallic inclusions at the microstructure of bearings are one of the most important reasons for fatigue damage initiation since they act as stress risers. In order to evaluate the stress state around such inclusions at the micro-scale, macroscopic stress histories are determined by Hertzian contact theory at different depths below the raceway for a typical roller bearing. These stress distributions are then used as far-field stresses for a micro-scale model accounting for single inclusions of different geometries and orientations. Eshelby’s method is used to relate far-field and local stresses in the vicinity of inclusions. The von Mises stress criterion is then used as a conservative estimator of crack initiation due to micro-scale plasticity. The effect of compressive residual stresses added to the axial and circumferential normal stress components at different depths is analyzed. The von Mises stress field around different inclusions at different depths is investigated in order to determine the most critical case in terms of micro-scale plastic deformation. Finally, an optimization process is carried out in order to determine the residual stresses that minimize the maximum observed von Mises stress as a function of depth.


Wear ◽  
2020 ◽  
Vol 446-447 ◽  
pp. 203207 ◽  
Author(s):  
Dongfang Zeng ◽  
Tian Xu ◽  
Weidong Liu ◽  
Liantao Lu ◽  
Jiwang Zhang ◽  
...  

2019 ◽  
Vol 140 ◽  
pp. 105849 ◽  
Author(s):  
Mostafa El Laithy ◽  
Ling Wang ◽  
Terry J. Harvey ◽  
Bernd Vierneusel ◽  
Martin Correns ◽  
...  

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Gao Xue Hai ◽  
Huang Xiao Diao ◽  
Hong Rong Jing ◽  
Wang Hua ◽  
Chen Jie

Rolling contact fatigue (RCF) corresponds to the formation of the first spall, which is a stochastic behavior; therefore, the RCF life should be reliably calculated. A method for evaluating RCF reliability was developed based on the Lundberg-Palmgren theory and ISO 281. The method took into consideration the contact load, the geometric parameters of contact pairs, the oscillation amplitude, the RCF reliability and the material properties. Because the method was derived from a widely accepted theory and empirical standards, it can be used for engineering applications. Finally, the RCF reliability of a slewing bearing under complex operating conditions was determined using the developed method.


2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Wanliang Huang ◽  
Xi Cao ◽  
Zefeng Wen ◽  
Wenjian Wang ◽  
Qiyue Liu ◽  
...  

With a subscale rolling-sliding apparatus, the objective of this study is to explore the adhesion and rolling contact fatigue characteristics of wheel/rail rollers with sanding under water condition. Sanding improves adhesion coefficient but aggravates the surface damage of wheel and rail materials. With the particle diameter and feed rate increasing, the adhesion coefficient is further improved. However, the surface damage (spalling and pits) becomes severer as well as the surface roughness. Note that pitting is a special damage type when sanding is used to improve the adhesion. Big pits and fatigue cracks appear on subsurface under larger particle diameter and feed rate conditions. Severe cracks initiate from big pits and develop into material to a depth, which results in bulk material breaking.


2021 ◽  
Author(s):  
Graham Keep ◽  
Mark Wolka ◽  
Beth Brazitis

Abstract Through hardened steel ball fatigue failure is an atypical mode of failure in a rolling element bearing. A recent full-scale bench test resulted in ball spalling well below calculated bearing life. Subsequent metallurgical analysis of the spalled balls found inferior microstructure and manufacturing methods. Microstructural analysis revealed significant carbide segregation and inclusions in the steel. These can result from substandard spheroidized annealing and steel making practices. In addition, the grain flow of the balls revealed a manufacturing anomaly which produced a stress riser in the material making it more susceptible to crack initiation. The inferior manufactured balls caused at least an 80% reduction in rolling contact fatigue life of the bearing.


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