Surface effects in rolling contact fatigue: the role of lubricant additives on the incidence of failure

Author(s):  
D. Scott
Author(s):  
D. Ne´lias ◽  
C. Jacq ◽  
G. Lormand ◽  
G. Dudragne ◽  
A. Vincent

A new methodology is proposed to evaluate the rolling contact fatigue (RCF) performances of bearing steels in presence of surface dents. The experimental procedure consists in denting the raceway of the test specimen with a hardness machine using spherical diamond tips of different radius, i.e. 200, 400 and 600 μm, and normal loads ranging from 5 to 50 daN. Analysis of various dent geometries yields to an analytical law with five parameters useful to fit experimental profiles for contact simulation. Besides local residual stresses and plastic strains around the dent have been obtained by finite element simulations of the indentation process. RCF tests performed on a two-disk machine have shown better performances of nitrided 32CrMoV13 steel compared to M50 reference steel. The dominating role of sliding has been highlighted and two areas where damage initiates were identified, while the effects of the normal load and hoop stresses are less marked.


Wear ◽  
2008 ◽  
Vol 265 (9-10) ◽  
pp. 1363-1372 ◽  
Author(s):  
John E. Garnham ◽  
Claire L. Davis

Wear ◽  
2017 ◽  
Vol 382-383 ◽  
pp. 113-122 ◽  
Author(s):  
Benoit L’Hostis ◽  
Clotilde Minfray ◽  
Marion Frégonèse ◽  
Catherine Verdu ◽  
Benoit Ter-Ovanessian ◽  
...  

1971 ◽  
Vol 93 (2) ◽  
pp. 231-233 ◽  
Author(s):  
Paul Schatzberg

Water in lubricating oils causes a significant reduction in rolling-contact fatigue life. This effect can be inhibited by lubricant additives that interfere with the mechanism by which water reduces fatigue life. Using a planetary four-ball machine, it is demonstrated that the addition of 0.1 percent isopropylaminoethanol completely counteracts the detrimental influence due to 1 percent seawater emulsified with the lubricant. It is suggested that the aminoalcohol condenses into surface microcracks along with water, captures hydrogen ions formed within the crack and thereby inhibits hydrogen embrittlement.


Author(s):  
M Meheux ◽  
C Minfray ◽  
F Ville ◽  
T L Mogne ◽  
A A Lubrecht ◽  
...  

1963 ◽  
Vol 85 (3) ◽  
pp. 439-447 ◽  
Author(s):  
E. V. Zaretsky ◽  
L. B. Sibley ◽  
W. J. Anderson

The five-ball fatigue tester was used to determine the rolling-contact fatigue life of 1/2-inch-diameter M-1 steel balls with four lubricants at 300 deg F. Film thickness measurements were made with the rolling-contact disk machine under simulated five-ball test conditions. Under certain conditions, elastohydrodynamic lubrication was found to exist at initial maximum Hertz stress levels up to 800,000 psi. There appears to be a correlation among the following variables: Plastically deformed profile radius of the ball specimen at ambient temperature; lubricant type; and rolling-contact fatigue. No correlation was found between contact temperature obtained with different lubricants and fatigue life.


1998 ◽  
Vol 120 (2) ◽  
pp. 184-190 ◽  
Author(s):  
D. Ne´lias ◽  
M.-L. Dumont ◽  
F. Couhier ◽  
G. Dudragne ◽  
L. Flamand

The purpose of this investigation is to clarify the role of roughness on rolling contact fatigue. Tests have been carried out on a two-disk machine, for two rolling bearing steels (52100 and M50), two surface roughnesses corresponding to EHL and micro-EHL conditions (two different surface finishing), three normal loadings (1.5, 2.5 and 3.5 GPa), and under pure rolling or rolling plus sliding conditions. No surface damage has been observed up to 50 106 cycles for tests with smooth specimens. Tests with rough specimens have produced a typical surface damage, called here surface distress, made of a large population of asperity-scale micro-cracks and micro-spalls. The paper describes the surface distress observed, such as micro-cracks and micro-spalls. Surface damages obtained are different for tests under pure rolling conditions and tests under rolling plus sliding conditions. Therefore, the role of the friction direction is underlined. A link is made between our experimental observations and calculations that have been carried out using a transient EHL model. The influence of an indent in a line contact, simulating a micro-spall, is studied. Surface pressure and associated sub-surface stress field are analyzed versus the sliding direction.


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