The influence of type of dispersed phase on rolling contact fatigue of lubricating greases on mineral base oil

The paper discusses the influence of type dispersed phase on value of rolling contact fatigue of bearings lubricated with selected lubricating compositions. The compositions, which were produced on the mineral base oil were thickened of lithium stearate, calcium stearate, aluminum stearate, lithium complex soap and modified silica, montmorillonite, and polytetrafluoroethylene were evaluated. Were carried out the investigations of rolling contact fatigue (pitting) of bearings, which were lubricated of the compositions prepared on the above-mentioned thickeners. Then was evaluated the influence of various thickeners on changes of rolling contact fatigue. The tribological tests were carried out using T-03 four-ball machine under high load conditions. On the basis of obtained results it may be concluded, that used of thickeners such as: modified amorphous silica, montmorillonite and polytetrafluoroethylene to produce of lubricating compositions, positively affected on the change of rolling contact fatigue of tribosystems lubricated with the above-mentioned compositions in comparison to the compositions, when as a dispersed phase were used a soap thickeners.

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THE INFLUENCE OF DIFFERENT VEGETABLE DISPERSION PHASES ON THE ROLLING CONTACT FATIGUE OF BIODEGRADABLE LUBRICATING GREASES

Tribologia ◽

10.5604/01.3001.0010.6716 ◽

2016 ◽

Vol 270 (6) ◽

pp. 57-67

Author(s):

Rafał KOZDRACH

Keyword(s):

Vegetable Oils ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

High Load ◽

Rolling Contact ◽

Lubricating Grease ◽

Dispersion Phase ◽

Base Oil ◽

Mineral Oils ◽

Favourable Change

The paper discusses the influence of the vegetable dispersion phase on the rolling contact fatigue of bearings lubricated with ecological lubricating compositions. Four vegetable oils were used for the production of lubricating greases: rapeseed, sunflower, soybean, and castor. For comparison purposes, the synthetic and mineral oils were used as well. The rolling contact fatigue (pitting) of bearings lubricated with particular compositions were investigated and evaluated for each base oil. The tribological tests were carried out using T-03 four-ball machine under high load conditions. Based on the obtained results, it may be concluded that vegetable oils, such as rapeseed, sunflower and castor, as the base of lubricating grease positively affected the rolling contact fatigue of tribosystems lubricated with the above-mentioned compositions in comparison to the control lubricated with greases based on mineral or synthetic oil. There is no favourable change in rolling contact fatigue of tribosystems lubricated with greases based on soybean oil.

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The Effect of AW/EP Additives on Rolling Contact Fatigue of the Coated Parts

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-63430 ◽

2005 ◽

Author(s):

Remigiusz Michalczewski ◽

Witold Piekoszewski ◽

Marian Szczerek

Keyword(s):

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Reactive Sputtering ◽

Cyclic Stress ◽

Rolling Contact ◽

Base Oil ◽

Surface Fatigue ◽

Rolling Contacts ◽

Crn Coatings ◽

Mineral Base

The paper concerns the influence of lubricants on surface fatigue of coated elements. As lubricants a mineral base oil and its mixtures with AW/EP additives were used. TiN and CrN coatings were deposited using the arc-vacuum technique, and WC/C by reactive sputtering. The tests were performed using a cone-three ball tester. The worn surfaces were observed employing SEM and analyzed using EDS technique. The results show that coatings like TiN and CrN do not exhibit a satisfactory resistance to cyclic stress. Only WC/C coatings, in rolling contacts may prolong the life of heavy-loaded machine components.

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Evaluation of contact fatigue life of a wind turbine carburized gear considering gradients of mechanical properties

International Journal of Damage Mechanics ◽

10.1177/1056789518814284 ◽

2018 ◽

Vol 28 (8) ◽

pp. 1170-1190 ◽

Cited By ~ 5

Author(s):

Wei Wang ◽

Huaiju Liu ◽

Caichao Zhu ◽

Zhangdong Sun

Keyword(s):

Residual Stress ◽

Fatigue Life ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Heavy Duty ◽

Initial Residual Stress ◽

Contact Fatigue Life ◽

Carburized Gear ◽

Load Conditions

Case hardening processes such as carburizing are extensively applied in heavy-duty gears used in wind turbines, ships, high-speed rails, etc. Contact fatigue failure occurs commonly in engineering practice, thus reduces reliabilities of those machines. Rolling contact fatigue life of a carburized gear is influenced by factors such as the gradients of mechanical properties and profile of initial residual stress. In this regard, the study of contact fatigue life of carburized gears should be conducted with the consideration of those aspects. In this study, a finite element elastic–plastic contact model of a carburized gear is developed which takes the gradients of hardness and initial residual stress into account. Initial residual stress distribution and the hardness profile along the depth are obtained through experimental measurements. The effect of the hardness gradient is reflected by the gradients of yield strength and fatigue parameters. The modified Fatemi–Socie strain-life criterion is used to estimate the rolling contact fatigue life of the heavy-duty carburized gear. Numerical results reveal that according to the Fatemi–Socie fatigue life criterion, rolling contact fatigue failure of the carburized gear will first initiate at subsurface rather than surface. Compared with the un-carburized gear, the rolling contact fatigue lives of the carburized gear under all load conditions are significantly improved. Under heavy load conditions, the carburized layer significantly reduces the fatigue damage mainly due to the benefit to inhibit the accumulation of plasticity. Influence of the residual stress is also investigated. Under the nominal load condition, compared with the residual stress-free case, the existence of the tensile residual stress causes remarkable deterioration of the rolling contact fatigue life while the compressive residual stress with the same magnitude leads to a moderate growth of the rolling contact fatigue life. As the load becomes heavier when plasticity becomes notable, the influence of the initial residual stress on the life is somewhat weakened.

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