Traction Coefficients for Coated Bearing Races Lubricated With Teflon Transfer Films

1991 ◽  
Vol 113 (2) ◽  
pp. 343-348 ◽  
Author(s):  
D. W. Dareing
Keyword(s):  
Coefficient Of Friction ◽  
Operation Time ◽  
Published Data ◽  
Coating Film ◽  
Metallic Surfaces ◽  
Current Time ◽  
Transfer Films ◽  
The Coefficient Of Friction ◽  
Soft Metal ◽  
Engine Maintenance

The paper evaluates different soft metal coatings for use in conjunction with teflon transfer films. The work was directed at angular contact bearings. The overall goal was to reduce friction within the bearings and thus increase operation time between engine maintenance beyond current time levels. The paper gives a mathematical model which accounts for elastic deflections in coating, film, and substrates. Predicted traction forces are in agreement with published data. Calculations show that traction coefficients reduce when the coefficient of friction is reduced and surface flexibility is increased. Teflon has a low coefficient of friction (f ≈ 0.10) against nearly all metallic surfaces and is relatively flexible even at cryogenic temperatures. In order to reduce traction coefficients with surface coatings in parallel with teflon transfer films, the coating must bring about a lower coefficient of friction or increase surface flexibility.

The Influence of Surface Roughness on the Mechanism of Friction

1970 ◽  
Vol 92 (2) ◽  
pp. 264-272 ◽  
Author(s):  
T. Tsukizoe ◽  
T. Hisakado
Keyword(s):  
Surface Roughness ◽  
Metal Surface ◽  
Coefficient Of Friction ◽  
Dry Friction ◽  
Metal Surfaces ◽  
Roughness Effects ◽  
Real Area Of Contact ◽  
The Coefficient Of Friction ◽  
Tangential Forces ◽  
Soft Metal

A study was made of surface roughness effects on dry friction between two metals, assuming that the asperities are cones of the slopes which depend on the surface roughness. The theoretical explanations were offered for coefficients of friction of the hard cones and spheres ploughing along the soft metal surface. A comparison of calculated values based on these with experimental data shows good agreement. Moreover, theoretical discussion was carried out of surface roughness effects on dry friction between two metal surfaces on the basis of the analyses of the frictional mechanism for a hard slider on the metal surface. The theoretical estimation of the coefficient of friction between two metal surfaces can be carried out by using the relations between the surface roughness and the slopes of the asperities, and the coefficient of friction due to the adhesion at the interface. The experiments also showed that when two metal surfaces are first loaded normally and then subjected to gradually increasing tangential forces, real area of contact between them increases and the maximum tangential microslip of them increases with the increase of the surface roughness.

Predicting the Coefficient of Friction in Sliding-Rolling Contacts

1989 ◽  
Vol 111 (2) ◽  
pp. 386-390 ◽  
Author(s):  
Yufeng Li ◽  
Ali Seireg
Keyword(s):  
Surface Roughness ◽  
Coefficient Of Friction ◽  
Thermal Regime ◽  
Surface Coating ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Published Data ◽  
Excellent Correlation ◽  
Rolling Contacts ◽  
The Coefficient Of Friction

This paper deals with the development of a dimensionless empirical formula for calculating the coefficient of friction in sliding-rolling steel on steel contacts under different operating conditions in the thermal regime. The effect of lubrication, surface roughness, and surface coating on friction are considered. The formula shows excellent correlation with the experimental tests conducted by many investigators and provides a unified relationship for all the published data.

Correlating the Features of Topography to Friction by Sliding Experiments

2008 ◽  
Author(s):  
Anirudhan Pottirayil ◽  
Pradeep L. Menezes ◽  
Satish V. Kailas
Keyword(s):  
Sheet Metal ◽  
Coefficient Of Friction ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Work Piece ◽  
Manufacturing Processes ◽  
Experimental Procedure ◽  
The Coefficient Of Friction ◽  
Soft Metal

Friction can influence the quality of the finished product to a large extent in certain manufacturing processes. Sheet metal forming is a particular case, where the friction between the hard-die and the relatively soft work-piece can be extremely important. Under such conditions, topography of the harder surface can influence the resistance to traction at the interface. This paper discusses about the correlation between certain features of the surface topography and coefficient of friction based on experiments involving sliding of a few soft metal pins against a harder material. A brief description of the experimental procedure and the analysis are presented. A hybrid parameter which encapsulates both the amplitude features as well as the relative packing of peaks is shown to correlate well with the coefficient of friction.

scholarly journals Experimental and Analytical Investigations on Tribological Properties of PTFE/AP Composites

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4295
Author(s):  
Hai Wang ◽  
Annan Sun ◽  
Xiaowen Qi ◽  
Yu Dong ◽  
Bingli Fan
Keyword(s):  
Wear Resistance ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Chemical Structure ◽  
Element Composition ◽  
Support Material ◽  
Test Conditions ◽  
Transfer Films ◽  
The Coefficient Of Friction

The tribological properties of polytetrafluoroethylene (PTFE)/AP (poly(para-phenyleneterephthalamide) (PPTA) pulp) composites under different test conditions (load: 2N, 10N; frequency: 1 Hz, 4 Hz; amplitude: 2 mm, 8 mm) were holistically evaluated. PTFE/AP composites with different AP mass ratios of 3%, 6%, and 12% as a skeleton support material were prepared. The coefficient of friction (COF) and wear rate were determined on a ball-on-disk tribometer. Furthermore, the morphology, element composition, and chemical structure of the transfer membrane were analyzed accordingly. The relationships between load, frequency, amplitude, and tribological properties were further investigated. According to the wear mechanism, AP enables effective improvement in the stiffness and wear resistance, which is also conducive to the formation of transfer films.

Frictional Properties of a Surface Covered With a Soft Metal Film—Part 1: Experiments on Friction Between a Single Protuberance and a Surface

1981 ◽  
Vol 103 (2) ◽  
pp. 236-242 ◽  
Author(s):  
S. Kato ◽  
K. Yamaguchi ◽  
E. Marui ◽  
K. Tachi
Keyword(s):  
Coefficient Of Friction ◽  
Deformation Mechanism ◽  
Metal Film ◽  
Surface Film ◽  
Thin Metal Film ◽  
Film Properties ◽  
Empirical Expression ◽  
Frictional Properties ◽  
The Coefficient Of Friction ◽  
Soft Metal

Frictional properties in the contact between a hard protuberance and a metal surface covered by a soft thin metal film are examined experimentally. The protuberance used in the experiment is a hard steel ball which simulates asperities on many engineering surfaces. The load dependency of the coefficient of friction and the effects of thickness and hardness of the film on the friction are clarified. The simple empirical expression of friction, which represents the effect of the film properties, is presented, considering the deformation mechanism of the surface film.

Slip Sliding Away — Slip Resistance of Athletic Socks on Indoor Flooring

2009 ◽  
Vol 53 (9) ◽  
pp. 568-571
Author(s):  
David G. Curry ◽  
Anne Mathias
Keyword(s):  
Coefficient Of Friction ◽  
Laboratory Study ◽  
Published Data ◽  
Slip Resistance ◽  
Significant Difference ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Flooring Materials

A laboratory study was conducted to assess the slip resistance of athletic socks on various household flooring materials under both wet and dry conditions. While prior studies regarding slip resistance have focused on shod walkers, there is a lack of published data on the coefficient of friction between stocking-clad feet and indoor flooring. To investigate this, four types of athletic socks were tested on samples of eight flooring materials for both wet and dry conditions. These results were compared to tests of a Neolite slider pad on these floors. The results indicated that for socks on textured vinyl flooring, there was no significant difference in slip resistance between the wet and dry conditions, though there was a trend towards greater slip resistance under wet conditions. Generally, it appears that the likelihood of slipping on other types of wet indoor walking surfaces is lower when walking in socks rather than shoes.

Frictional Properties of a Surface Covered With a Soft Metal Film—Part 2: Analysis of Friction Between a Single Protuberance and a Surface

1982 ◽  
Vol 104 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Shinobu Kato ◽  
Katsumi Yamaguchi ◽  
Etsuo Marui ◽  
Kiyoo Tachi
Keyword(s):  
Pressure Distribution ◽  
Coefficient Of Friction ◽  
Metal Film ◽  
Surface Film ◽  
Analytical Investigation ◽  
Friction Characteristic ◽  
Frictional Properties ◽  
The Coefficient Of Friction ◽  
Soft Metal ◽  
Side Flow

Analytical investigation of the evaluation of the coefficient of friction is made to clarify the mechanism of the load dependency of friction, which was obtained in Part 1 of this research, and also to ascertain the effects of the surface film on the friction characteristic. The plastic flow of the soft metal film between a protuberance and the subsurface is presumed, and the pressure distribution originating from the side flow is calculated on the basis of the plasticity theory. The effects of the coefficient of friction of the load, the thickness and hardness of the film, and the radius of the protuberance, are examined. As a result, it is clarified that the load dependency of friction arises from the extremely high pressure distribution generated in the film.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

scholarly journals Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4217
Author(s):  
Üsame Ali Usca ◽  
Mahir Uzun ◽  
Mustafa Kuntoğlu ◽  
Serhat Şap ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Applied Load ◽  
Practical Significance ◽  
Tribological Characteristics ◽  
M 10 ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Four Levels

Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 °C) were used. Taguchi’s L16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 °C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.

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