scholarly journals Tribological Investigation on the Friction and Wear Behaviors of Biogenic Lubricating Greases in Steel–Steel Contact

2020 ◽  
Vol 10 (4) ◽  
pp. 1477
Author(s):  
Nazli Acar ◽  
José M. Franco ◽  
Erik Kuhn ◽  
David E. P. Gonçalves ◽  
Jorge H. O. Seabra
Keyword(s):  
Friction And Wear ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Point Of View ◽  
Wear Model ◽  
Wear Process ◽  
Machine Element ◽  
Lubricant Analysis ◽  
Machine Elements ◽  
Tribological Contact

The applications of biogenic lubricating greases to machine elements play important roles in the reduction of friction energy and minimizing wear in a tribological contact, as well as the prevention of environmental pollution. The aim of this work was to investigate completely biogenic lubricating greases from a tribological point of view. Model greases were examined using a ball on a disc tribometer at a constant normal force to investigate the friction and wear process according to Fleischer’s energetic wear model. Using the energy-based wear model, the friction and wear process could be interpreted as a cause–effect sequence. Moreover, the influence of the model grease composition on the friction and wear process was analyzed. In addition, rolling bearing tests were performed to investigate the tribological behaviors of some selected biogenic greases during real machine element contact. These tests allowed for the quantification of the friction torque behavior of the full bearing and the evaluation of the wear obtained through lubricant analysis procedures. This experimental work provides useful information regarding the influence that the composition of biogenic model greases has on friction and wear behaviors in a tribological contact.

GreenBearings – Friction Behaviour of DLC-Coated Dry Running Deep Groove Ball Bearings

2015 ◽  
Vol 805 ◽  
pp. 147-153 ◽  
Author(s):  
Julia Kröner ◽  
Stephan Tremmel ◽  
Serge Kursawe ◽  
Yashar Musayev ◽  
Tim Hosenfeldt ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Energy Savings ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Wear Behaviour ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Pumping Stations ◽  
Deep Groove ◽  
First Results

Due to the use of rolling bearings instead of plain bearings friction and wear are drastically reduced in all kind of machines. However, despite the high technical standard of modern rolling bearings there is still a significant potential for optimization. Preliminary Studies show a reduction of the friction torque of up to 44 % compared to conventional rolling bearings because of the use of tribological coatings in certain applications. Based on the millionfold usage of rolling bearings in all industrial fields the reduced lost energy adds up to a remarkable potential for energy savings. If friction and wear are lowered sufficiently, the use of conventional lubricants based on mineral oil can be successively decreased or even completely avoided. In the latter case, the socalled dry running of the rolling bearing, the energy consumption of machines and systems can additionally be reduced significantly. For example, pumping stations or compressed air units, which would be necessary for transporting or spraying the lubricants, can then be saved.This paper presents first results of DLC-coated deep groove ball bearings, which are tested in a four-bearing-test-rig under purely radial load with respect to their friction and wear behaviour.

scholarly journals Investigations on Graphene Platelets as Dry Lubricant and as Grease Additive for Sliding Contacts and Rolling Bearing Application

Lubricants ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
Florian Pape ◽  
Gerhard Poll
Keyword(s):  
Experimental Studies ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Rolling Contact ◽  
Multilayer Graphene ◽  
Oil And Grease ◽  
Angular Contact Ball Bearing ◽  
Graphite Nanoparticles ◽  
Graphene Platelets ◽  
Tribological Contact

In recent years, graphene-based lubrication was in the focus of nano- and microtribological studies. While the sliding properties of graphene based dry lubrication were previously investigated on the nano- and micro-scale, few studies can be found in the literature for the application of graphene as an additive to oil and grease in rolling contacts. In order to apply graphene platelets as dry lubricants and as grease additives in machine elements, tests were carried out on a rolling bearing test rig under typical load conditions. For these investigations, multilayer graphene platelets of varied staple thickness were functionalized on angular contact ball bearing surfaces as a dry lubricant, which forms a thin film. In addition, bearings were lubricated with grease containing graphene platelets. In this case, a small ratio of graphene was dispersed with grease. The graphene platelets were divided into three groups of different thickness: 2 nm, 6–8 nm, and 11–15 nm. Additionally, the tests were compared to graphite nanoparticles (spheres with a size of 3–4 nm) as dry lubricant and graphite-containing grease. The experimental studies were carried out under oscillating motion. The respective load in the tribological contact was 1.5 GPa. During the tests, the pivoting angle was measured by utilizing a rotary encoder. In addition, the friction torque was recorded under a frequency of 0.2 Hz. As the balls’ velocity at the reversal point is zero, the lubrication conditions are critical. The dry lubricated bearings were compared to grease lubricated bearings. Additionally, the frictional properties of the respective greases were investigated by applying a sliding tribometer. In this case, a ball rotates against three contact planes, which causes a tribological contact under a contact pressure of 1 GPa. It was shown that applying graphene as a dry lubricant and as a grease additive under rolling contact conditions reduces friction significantly.

scholarly journals The Use of Statistical Functions for the Selection of Laser Texturing Parameters

2020 ◽  
Vol 10 (1) ◽  
pp. 454-461
Author(s):  
Piotr Sęk
Keyword(s):  
Surface Texturing ◽  
Point Of View ◽  
Laser Surface Texturing ◽  
Machining Parameters ◽  
Textured Surfaces ◽  
Surface Layers ◽  
Adhesion Properties ◽  
Machine Elements ◽  
Selection Of ◽  
Statistical Functions

AbstractLaser surface texturing is currently the most developed technique for producing fully reproducible microcavities on the surfaces of machine elements. From the point of view of texture technology, an important aspect is the proper selection of process parameters to obtain texture elements with desirable and repetitive geometries and physicochemical properties. Surface texturing improves mottling and fretting resistance and is also used wherever the adhesion properties of surface layers (printing techniques, bonding materials, biological and chemical activity, coatings, etc.) are important. The article shows the possibility of applying statistical functions to the selection of appropriate machining parameters to obtain microgeometry useful in the application of textured surfaces [1].

Wear Model for Piston Ring and Cylinder Bore System

2005 ◽  
Author(s):  
Yunchao Qiu ◽  
Qian Zou ◽  
Gary C. Barber ◽  
Harold E. McCormick ◽  
Dequan Zou ◽  
...  
Keyword(s):  
Piston Ring ◽  
Thickness Distribution ◽  
Matrix Ring ◽  
Experimental Investigations ◽  
General Tendency ◽  
Wear Model ◽  
Wear Process ◽  
The Matrix ◽  
Surface Profiles ◽  
Cylinder Bore

A new wear model for piston ring and cylinder bore system has been developed to predict wear process with high accuracy and efficiency. It will save time and cost compared with experimental investigations. Surfaces of ring and bore were divided into small domains and assigned to corresponding elements in two-dimensional matrix. Fast Fourier Transform (FFT) and Conjugate Gradient Method (CGM) were applied to obtain pressure distribution on the computing domain. The pressure and film thickness distribution were provided by a previously developed ring/bore lubrication module. By changing the wear coefficients of the ring and bore with accumulated cycles, wear was calculated point by point in the matrix. Ring and bore surface profiles were modified when wear occurred. The results of ring and bore wear after 1 cycle, 10 cycles and 2 hours at 3600 rpm were calculated. They coincided well with the general tendency of wear in a ring and bore system.

Investigation on the Tool Wear Model and Equivalent Tool Life in End Milling Titanium Alloy Ti6Al4V

2018 ◽  
Author(s):  
Kai Guo ◽  
Bin Yang ◽  
Jie Sun ◽  
Vinothkumar Sivalingam
Keyword(s):  
Tool Wear ◽  
Titanium Alloys ◽  
Tool Life ◽  
End Milling ◽  
Cutting Speed ◽  
Carbide Tool ◽  
Wear Model ◽  
Wear Process ◽  
Coated Carbide Tool ◽  
Coated Carbide

Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.

Performance of Plain Journal Bearings Operating Under Vortex Flow Conditions

1974 ◽  
Vol 96 (1) ◽  
pp. 145-149 ◽  
Author(s):  
J. Freˆne ◽  
M. Godet
Keyword(s):  
Reynolds Number ◽  
Friction Torque ◽  
Point Of View ◽  
Taylor Vortex ◽  
Experimental Program ◽  
Frictional Torque ◽  
Taylor Vortices ◽  
Attitude Angle ◽  
Relative Eccentricity ◽  
High Reynolds

An experimental program conducted on an original device was undertaken to study the performance of plain bearings operating at sufficiently high Reynolds number to introduce Taylor vortices. Curves of relative eccentricity, attitude angle, and friction torque were obtained versus speed and load. Experimental results conducted for Reynolds number smaller than 1100 indicate that both laminar and Taylor vortex regimes are encountered. The occurrence of the vortices is identified by a break in the slope of the friction torque versus speed curves. The position of the break is in good agreement with the theoretical predictions of Di Prima and Ritchie. From the practical point of view, the data show that for constant viscosity the occurence of Taylor vortices does not alter the curves of eccentricity versus either speed or load but modifies the attitude angle and frictional torque. In turn, the increase in frictional torque, and subsequently of temperature may cause a decrease in viscosity and thus a drop in load carrying capacity for fluids such as oils whose variations of viscosity with temperature is large.

Analysis of the Behaviour of Rolling Bearings in Contaminated Oil Using Some Condition Monitoring Techniques

2006 ◽  
Vol 220 (5) ◽  
pp. 447-453 ◽  
Author(s):  
T Akagaki ◽  
M Nakamura ◽  
T Monzen ◽  
M Kawabata
Keyword(s):  
Vibration Analysis ◽  
Wear Debris ◽  
Friction And Wear ◽  
Rolling Bearing ◽  
Rolling Bearings ◽  
Deep Groove ◽  
Deep Groove Ball Bearing ◽  
Observation Results ◽  
Wear Debris Analysis ◽  
Worn Surfaces

Friction and wear behaviours of rolling bearing in contaminated oil containing white-fused alumina particles were studied. The friction and wear processes were monitored using wear debris analysis, such as ferrography and spectrometric oil analysis program, and vibration analysis. Test bearing was a deep groove ball bearing (6002P5); Wear debris and worn surfaces of the bearing components were observed with a scanning electron microscope (SEM). It was found that the friction coefficient in the contaminated oil became lower by about 0.001 than that in the new oil for the large contaminants. The results of wear debris analysis showed that the large contaminants caused the high wear rate in the bearing. Three types of wear debris were commonly observed: thread-like debris, cutting chip debris, and plate-like debris. On the basis of the SEM observation results of the worn surfaces, wear mechanisms of these wear debris were discussed. The results of vibration analysis showed that the probability density function of vibration waveform was normal distribution in both the new and contaminated oils. In the contaminated oil, it changed depending on the contaminant size and the runtime, i.e. the progress of wear in the bearing. The result of wear debris analysis was related to that of vibration analysis and discussed.

Friction and wear model of a heavy loaded sliding pair

Wear ◽  
2000 ◽  
Vol 241 (1) ◽  
pp. 65-78 ◽  
Author(s):  
V.V. Kharlamov ◽  
V.L. Kolmogorov ◽  
S.V. Pavlishko
Keyword(s):  
Friction And Wear ◽  
Wear Model

A Numerical Simulation of Fretting Wear considering the Dynamic Evolution of Debris for the Coated Contact Surface

2021 ◽  
pp. 1-49
Author(s):  
Li Xiao ◽  
Yingqiang Xu ◽  
Zhiyong Chen
Keyword(s):  
Fretting Wear ◽  
Contact Pair ◽  
Dynamic Evolution ◽  
Wear Depth ◽  
Wear Coefficient ◽  
Wear Model ◽  
Wear Process ◽  
Dlc Coating ◽  
Wear Life ◽  
Wear Calculation

Abstract In this paper, a multi-layer body model in which material properties and wear coefficient change with node coordinates is proposed, so that the wear profile is not restricted by the singularity of the interface of the coated contact pairs. The conversion rate of the adhered particles was obtained to describe the growth and expansion of the debris at the fretting interface based on experiments, and the wear model of coated contact pair considering the dynamic evolution of the debris layer was established. By comparing the previous experimental and computational results, the wear calculation method proposed in this paper is more reasonable to predict the wear profile of the coated contact pair. In addition, the influence of the debris layer on the wear depth, friction width, and contact pressure in the fretting process is analyzed, indicating that the existence of the debris layer can delay the wear process. Finally, the fretting wear life of the SCMV steel contact pair deposited with the W-DLC coating is estimated.

scholarly journals Effect of Ionicity of Three Protic Ionic Liquids as Neat Lubricants and Lubricant Additives to a Biolubricant

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 713 ◽  
Author(s):  
Hong Guo ◽  
Angela Rina Adukure ◽  
Patricia Iglesias
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Friction And Wear ◽  
Cost Effective ◽  
Lubricant Additive ◽  
Lubricant Additives ◽  
Environmental Damage ◽  
Protic Ionic Liquids ◽  
Protic Ionic Liquid ◽  
Wear Process

Friction and wear of sliding surfaces are responsible for important energy losses and negative environmental effects. The use of environmentally friendly and cost-effective protic ionic liquids as neat lubricants and lubricant additives has the potential to increase the efficiency and durability of mechanical components without increasing the environmental damage. In this work, three halogen-free protic ionic liquids with increasing extent of ionicity, 2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexancate, and 2-hydroxydimethylammonium 2-ethylhexanoate, were synthesized and studied as neat lubricants and additives to a biodegradable oil in a steel–steel contact. The results show that the use of any protic ionic liquid as a neat lubricant or lubricant additive reduced friction and wear with respect to the biodegradable oil. The ionic liquid with the lowest ionicity reached the highest wear reduction. The one possessing the highest ionicity presented the poorest friction and wear behaviors as a neat lubricant, probably due to the more ionic nature of this liquid, which promoted tribocorrosion reactions on the steel surface. This ionic liquid performed better as an additive, showing that a small addition of this liquid in a biodegradable oil is enough to form protective layers on steel surfaces. However, it is not enough to accelerate the wear process with detrimental tribocorrosion reactions.

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