Chemical Effects of Lubrication in Contact Fatigue—Part III: Load-Life Exponent, Life Scatter, and Overall Analysis

1976 ◽  
Vol 98 (2) ◽  
pp. 308-315 ◽  
Author(s):  
W. E. Littmann ◽  
B. W. Kelley ◽  
W. J. Anderson ◽  
R. S. Fein ◽  
E. E. Klaus ◽  
...  
Keyword(s):  
Relevant Literature ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Zinc Dialkyldithiophosphate ◽  
Additive Package ◽  
Chemical Effects ◽  
Contact Fatigue Life ◽  
Program Show ◽  
Selection Of

A brief review of relevant literature is presented with the logic underlying the selection of lubricant base stocks, additives, materials, surface textures, and other variables used in contact fatigue tests under rolling-sliding conditions. Tests of selected combinations (mineral oil with and without a zinc dialkyldithiophosphate additive and a polyolester synthetic with and without its typical additive package) showed that lubricant chemistry affects the stress/life slope and the Weibull slope (scatter in life). Results of the overall program show that the relative contact fatigue life for different lubricant chemistries should be evaluated using operating conditions, especially stress and slip levels, near to expected application conditions.

Experimental Investigations Upon Fatigue Life of Circular Contacts With Transversal Furrow

2005 ◽  
Author(s):  
Delia F. Cerlinca ◽  
Emanuel N. Diaconescu
Keyword(s):  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Geometric Parameters ◽  
Rolling Contact ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Contact Fatigue Life

Rolling contact fatigue depends essentially on both surface and subsurface populations of defects. First, this paper describes experimental results obtained in rolling contact fatigue tests in the presence of a furrow oriented transversally to the race-way. Then an attempt to predict theoretically the effect of geometric parameters of the furrow upon contact fatigue life is described.

Effect of Lubricant Viscosity on Gearing Contact Fatigue Life

2012 ◽  
Vol 190-191 ◽  
pp. 1295-1301 ◽  
Author(s):  
Xiu Mei Qi ◽  
Chuang Kuan Gao ◽  
Zeng Qiang Zhang
Keyword(s):  
Fatigue Life ◽  
Contact Fatigue ◽  
Critical Value ◽  
Fatigue Tests ◽  
Numerical Calculations ◽  
Quantitative Relation ◽  
Test Results ◽  
Contact Fatigue Life ◽  
Lubricant Viscosity ◽  
Film Lubrication

The paper considers the effect of lubricant viscosity, ν, on the contact fatigue life, N, in gearing applications. More than 40 sets of the thermal non-Newtonian EHL numerical calculations and six sets of disc fatigue tests under the conditions ranging from the mixed to full film lubrication are used. The results show that for improving gearing fatigue life it is generally useful to increase lubricant viscosity. But it is not simply the case that the higher the lubricant viscosity, the better. When lubricant viscosity, ν, is less than a critical value, νcr, a quantitative relation of is seen in the test results; When ν > νcr, however, increasing lubricant viscosity is found to reduce the fatigue life. Based on this result, the paper raises questions concerning the accuracy of the lubrication factor recommended by ISO/6336:1996.

New Methodology to Evaluate the Rolling Contact Fatigue Performance of Bearing Steels With Surface Dents: Application to 32CrMoV13 (Nitrided) and M50 Steels

2005 ◽  
Vol 127 (3) ◽  
pp. 611-622 ◽  
Author(s):  
D. Nélias ◽  
C. Jacq ◽  
G. Lormand ◽  
G. Dudragne ◽  
A. Vincent
Keyword(s):  
Normal Load ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Experimental Result ◽  
Damage Initiation ◽  
Bearing Steels ◽  
Improved Performance

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.

Theory of Lubrication and Failure of Rolling Contacts

1961 ◽  
Vol 83 (2) ◽  
pp. 213-222 ◽  
Author(s):  
B. Sternlicht ◽  
P. Lewis ◽  
P. Flynn
Keyword(s):  
Fatigue Life ◽  
Contact Zone ◽  
High Speed ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Rolling Contact ◽  
Inlet Temperature ◽  
Fluid Properties ◽  
Contact Fatigue Life

The fatigue life of rolling-element bearings has been the subject of numerous investigations. Most recently the influence of the lubricant on fatigue failure has been given added emphasis. This paper presents the results of an investigation which was undertaken in order to gain a better understanding of fluid behavior in the contact zone and to determine the influence of the lubricant on rolling contact fatigue life. The investigation had three distinct facets: (a) An analysis was performed on pressure and temperature distribution within the contact zone of rolling disks. In the analysis Reynolds, energy, and elasticity equations were solved simultaneously and fluid properties, such as viscosity dependence on temperature and pressure were included. (b) Dynamic stresses in two contacting cylindrical bodies were measured by means of photoelastic techniques. These measurements were used to test the validity of the analytically predicted stress distribution. (c) High-speed ball-bearing fatigue tests were conducted with two specially blended oils which had the same viscosity at the bearing inlet temperature, but widely different pressure viscosity characteristics. The physical characteristics of the oils were the same as those considered in the analysis. The paper summarizes the work and presents a hypothesis for the failure mechanism.

scholarly journals Influence of the axial loads of rolling stock on the contact-fatigue life of rails

2018 ◽  
Vol 77 (3) ◽  
pp. 149-156 ◽  
Author(s):  
V. S. Kossov ◽  
G. M. Volokhov ◽  
O. G. Krasnov ◽  
M. N. Ovechnikov ◽  
A. L. Protopopov ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Contact Fatigue ◽  
Calculated Data ◽  
Operating Conditions ◽  
Rolling Stock ◽  
Axial Loads ◽  
Rolling Surface ◽  
Contact Fatigue Life ◽  
The Impact

Analysis of operational data for defective and highly defective rails showed that up to 25 % is the contact-fatigue defects. In connection with the development of heavy haul traffic on the Russian railways, it is relevant to determine the influence of cars with increased axial loads of 25 and 27 tf on the contact fatigue life of rails. The solution of this problem is set forth in this article. The Brown-Miller model of multi-axial fatigue was used in the calculation. This model is integrated into the Fatigue software system, which is tied to the Marc calculation system through Pat-ran. Since under operating conditions the wheel moves (rolls) along the rail on meandering trajectory, in computer modeling weight coefficients were taken into account that characterize the percentage of wheels in the cross-sectional areas of the rail. Calculations of contact fatigue life took into account the variability of vertical loads from the impact on the track of trains formed from innovative open cars with axial loads of 23.5, 25 and 27 tf under operating conditions, loaded with real loading blocks. According to the analysis of calculated data with an increase in axial loads from 23.5 to 25 tf, it is necessary to expect a decrease in the service life of rails in contact fatigue resistance by 19 %, with a further increase in axle loads of up to 27 tf per 32 %. Considering that the share of freight cars with axial loads of 25 tf does not exceed 15...20 %, then on the routes of its use the service life of rails should be expected to decrease by 3...4 %. The method proposed by the authors for predicting the contact fatigue life of rails with increasing axial loads is advisable to improve in part of the experimental determination of the fatigue and strength characteristics of rail steel from the degree of hardening of the rolling surface, its probabilistic properties and the use of the integral distribution law for vertical forces, taking into account the structure of the freight traffic passing through the section. The work was carried out according to the RFBR project 17-20 01088.

Research on Contact Fatigue Properties of Some Materials Used for Heavy Load Gear

2010 ◽  
Vol 139-141 ◽  
pp. 360-363
Author(s):  
Ying Xia Yu ◽  
Bo Lin He ◽  
Er Yu Shao
Keyword(s):  
Fatigue Life ◽  
Crack Propagation ◽  
Maximum Shear Stress ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Heavy Load ◽  
Contact Fatigue Life ◽  
Materials Used

The contact fatigue tests were carried out using three kind of steel(45, 42CrMo, 40CrNi2Mo) which were quenched and tempered to the same medium hardness(HRC37±1). The experimental equipment is JPM-1 type contact fatigue tester. During the experiment process, the contact stress is 1600MPa and the surface roughness is 0.4 um. The crack initiation and the crack propagation direction were observed by using SEM. The contact fatigue failure mechanism was also analyzed. The experimental results were analyzed by using Weibull distribution. The experimental results show that the contact fatigue crack was initiated in the roller surface. With increasing of the cycle, the initiated crack propagates into subsurface and becomes to pitting. The pitting becomes bigger and bigger and leads to failure finally. The maximum shear stress is the main driving force for the crack propagation. The contact fatigue life increases in sequence of 45, 42CrMo, 40CrNi2Mo. The contact fatigue life has the relationship with the shearing resistant stress Тk. About the same carbon content, the value of the shearing resistant stress Тk becomes greater with increasing the alloying elements. The best material used for making heavy duty gear is 40CrNi2Mo steel.

scholarly journals Assessment of tribotechnical properties and resistance to wear of plasma coatings

2021 ◽  
pp. 95-108
Author(s):  
Alexandr O. Tokarev ◽  
Lyubov D. Makagon Makagon
Keyword(s):  
Sliding Friction ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Operational Tests ◽  
Cavitation Wear ◽  
Cyclic Impact ◽  
Plasma Technologies

In order to determine the operating conditions of parts for which restoration of worn surfaces is acceptable by the method of plasma spraying of various powder alloys, contact fatigue tests were carried out under cyclic contact impulse loading. In addition, tribotechnical tests were carried out with various wear-resistant coatings under conditions of liquid sliding friction. Bench and operational tests showed the use of coatings obtained using modern plasma technologies, the feasibility of protecting parts operating in conditions of corrosion, waterjet and cavitation wear, as well as in sliding friction. The coating sprayed with Ni-Al intermetallic alloy powder provides the most reliable protection against shock cyclic impact and abrasion during liquid friction than other materials studied. Coating with wear-resistant self-fluxing powder Ni-Cr-B-Si-C alloy, hardened by solid carboboride phases, without its additional heat treatment for restoration of surfaces working in sliding friction pairs, is not recommended.

Effects of material heterogeneity on surface fatigue for rough lubricated rolling–sliding contacts

2016 ◽  
Vol 231 (2) ◽  
pp. 274-290 ◽  
Author(s):  
Guillermo E Morales-Espejel ◽  
Hugo Boffy ◽  
CH Venner
Keyword(s):  
Contact Fatigue ◽  
Heterogeneous Materials ◽  
Heterogeneous Material ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Small Scale ◽  
Surface Fatigue ◽  
Subsurface Material ◽  
Contact Fatigue Life ◽  
Optimisation Methods

In view of increasingly severe operating conditions and the use of composite (strongly) heterogeneous materials, detailed modelling and optimisation methods are needed to predict the effects of subsurface material topology, either by design or resulting from inclusions and material anisotropy, on rolling-sliding contact fatigue life. In this paper, a method is proposed showing that such predictions can at present be obtained for realistic configurations on small-scale computers by integrating efficient numerical solution of the 3D displacement and stress field in the (heterogeneous) material with fast rough surface-lubricated contact models. Contact pressures, subsurface stresses and surface fatigue effects are shown for cases of bonded individual or multiple (clusters) of statistically distributed inhomogeneities close to the surface in realistic actual rolling–sliding rough contact geometries. The model contributes to the development of optimised failure criteria for composite/heterogeneous materials close to the surface.

Contact Fatigue Tests and Contact Fatigue Life Analysis

2005 ◽  
Author(s):  
Hong Lin ◽  
Robert R. Binoniemi ◽  
Gregory A. Fett ◽  
Mick Deis
Keyword(s):  
Fatigue Life ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Contact Fatigue Life ◽  
Life Analysis ◽  
Fatigue Life Analysis
Sign in / Sign up

Export Citation Format

Share Document