A Global Tribological Approach of Friction Dry Contact Polymer with SGF on Steel, in Terms of Consequences on Metallic Surface Condition (Comparative Wear Coefficients of Steel Surface)

2015 ◽  
Vol 723 ◽  
pp. 927-942 ◽  
Author(s):  
Virgil Florescu ◽  
Lucian Capitanu ◽  
Dorin Rus
Keyword(s):  
Friction Coefficient ◽  
Steel Surface ◽  
Plastic Material ◽  
Normal Load ◽  
Contact Temperature ◽  
Metallic Surface ◽  
Linear Wear ◽  
Sliding Speed ◽  
Dry Contact ◽  
Steel Surfaces

In this paper, we present a global tribological approach of friction dry contact polymer with SGF on steel, in terms of consequences on metallic surface condition (comparative wear coefficients of polished steel surface) based on extensive experimental determinations between the value and the evolution of the friction coefficient, wear of steel surfaces and contact temperature, in the case of linear dry contact, for thermoplastic material reinforced with short glass fibers (SGF) and various steel surfaces. The aim was to highlight the evolution of the wear process depending on the friction coefficient, as well as the dependence of the loading wear and the sliding speed. Wear depth and volume were calculated based on the “wear imprint” method. As a result, it was possible to graphically illustrate the evolution of the friction coefficient, of the contact temperature, and the change of the wear process, emphasizing the abrasive, adhesive and corrosive wear. The evolution of the plastic material transfer function of the contact temperature, namely of the power lost by friction was highlighted. It has been demonstrated that in the case of a 30% SGF content it can reach and even exceed contact temperatures very close to the yield limit of the plastic material. The influence of the normal load and sliding speed was evaluated in detail. The influence of SGF content, normal load, relative sliding speed and contact temperature over the metal surface wear and over the nature of wear mechanism was recorded. The reaction to wear of different steel surfaces in linear dry friction contact on polymers with SGF (polyamide + 20% SGF, polyamide + 30% SGF and polycarbonate with 20% SGF), observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.). Thus, authors' findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component are presented, which generally is specific to the polymers’ friction. Authors’ detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4mm/h, respectively the order of volumetric wear rate is of 10-6cm3/h. The resulting comparative volumetric wear coefficients are of the order (10-11to 10-12) cm3/cm and respectively linear wear coefficients of 10-9mm/cm.

Boundary Lubrication Model under Square Surface Contact Condition

2010 ◽  
Vol 29-32 ◽  
pp. 1396-1401
Author(s):  
Wei Zu Wang ◽  
Liu Yi Wang ◽  
Zeng Xue Zhang ◽  
Hai Bo Chen
Keyword(s):  
Friction Coefficient ◽  
Boundary Lubrication ◽  
Contact Area ◽  
Normal Load ◽  
Contact Temperature ◽  
Sliding Speed ◽  
Surface Contact ◽  
Relative Deficiency ◽  
Frictional Surfaces ◽  
Relationship Of

The contact temperature of the frictional surfaces under boundary lubrication in square surface contact is calculated according to classic heat conduction theories. The friction coefficient of boundary lubrication is expressed with the friction coefficient of boundary film and direct contact. Then, a model is developed based on the relationship of adsorption heat, friction coefficient and contact temperature. The model is used to solve a sample question. The results illuminate that when the applied load is relatively small, the friction coefficient keeps at a stable small value with the variation of the sliding speed and the load. However, when the load reaches a certain value, the increase of the sliding speed or the normal load both leads to the increase of the friction coefficient. The friction coefficient is also increases with the increase of the contact temperature. The relative deficiency of oil, which indicates the proportion of the true contact area to mean contact area, has almost the same variation trend of the friction coefficient.

The Dependence of the Friction Coefficient on the Size and Course of Sliding Speed

2014 ◽  
Vol 693 ◽  
pp. 305-310 ◽  
Author(s):  
Eva Labašová
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
Testing Machine ◽  
Current Component ◽  
Sliding Speed ◽  
Rectangular Shape ◽  
Coefficient Increase ◽  
The Coefficient Of Friction ◽  
Ring Method ◽  
Run Up

The coefficient of friction for the bronze material (CuZn25Al6) with insert graphite beds and other bronze material (CuSn12) are investigated in this paper. Friction coefficient was investigated experimentally by the testing machine Tribotestor`89 which uses the principle of the ring on ring method. The external fixed bushing was exposed to the normal load of the same size in all tests. Process of load was increased from level 50 N to 600 N during run up 300 s, after the run up the appropriate level of load was held. The internal bushing performed a rotational movement with constant sliding speed. The value of sliding speed was changed individually for every sample (v = 0.2 (0.3, 0.4) m.s-1). The forth test had a rectangular shape of sliding speed with direct current component 0.3 m.s-1 and the amplitude 0.1 m.s-1 period 300 s, the whole test took 2100 s. The obtained results reveal that friction coefficient increase with the increase of sliding speed.

Piston Ring-Cylinder Bore Friction Modeling in Mixed Lubrication Regime: Part II—Correlation With Bench Test Data

1999 ◽  
Vol 123 (1) ◽  
pp. 219-223 ◽  
Author(s):  
Ozgen Akalin ◽  
Golam M. Newaz
Keyword(s):  
Friction Coefficient ◽  
Test Data ◽  
Piston Ring ◽  
Normal Load ◽  
Test System ◽  
Mixed Lubrication ◽  
Contact Temperature ◽  
Bench Test ◽  
Crank Angle ◽  
Contact Width

A bench friction test system for piston ring and liner contact, which has high stroke length and large contact width has been used to verify the analytical mixed lubrication model presented in a companion paper (Part 1). This test system controls the speed, temperature and lubricant amount and records the friction force, loading force, crank angle signal and contact temperature data simultaneously. The effects of running speed, applied normal load, contact temperature and surface roughness on friction coefficient have been investigated for conventional cast-iron cylinder bores. Friction coefficient predictions are presented as a function of crank angle position and results are compared with bench test data. Analytical results correlated well with bench test results.

scholarly journals Effect of Self-Generated Transfer Layer on the Tribological Properties of PTFE Composites Sliding against Steel

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 399 ◽  
Author(s):  
Ting Xie ◽  
Shihao Feng ◽  
Yongheng Qi ◽  
Ailong Cui
Keyword(s):  
Friction Coefficient ◽  
Layer Thickness ◽  
Tribological Properties ◽  
Normal Load ◽  
Wear Test ◽  
Wear Volume ◽  
Functional Requirements ◽  
Transfer Layer ◽  
Sliding Speed ◽  
Ptfe Composites

Coatings are normally employed to meet some functional requirements. There is a kind of self-generated coating during use, such as the transfer layer during sliding, which may greatly affect the tribological behavior. Although the transfer layer has aroused much attention recently, the formation of the transfer layer closely depends on the service conditions, which need to be further studied. In this paper, the effects of sliding speed, normal load, and duration of wear test on the transfer layer thickness during friction of Ni/PTFE (Polytetrafluoroethylene) composites were experimentally investigated. The formation mechanism of transfer layer and the relationships between tribological properties and transfer layer thickness were analyzed in detail. It was found that the transfer layer thickness increased with increases of sliding speed and normal load; and after a period of wear test, the transfer layer thickness remained stable. The transfer layer thickness correlates linearly with the friction coefficient and wear volume of the PTFE composites. With the increase of the transfer layer thickness, the friction coefficient decreased, while the wear volume increased, which means that a uniform, thin, and stable transfer layer is beneficial for the reduction of friction and wear of the polymeric composites.

The Effect of Sliding Speed on Friction and Wear of RBD Palm Olein

2013 ◽  
Vol 315 ◽  
pp. 951-955 ◽  
Author(s):  
Samion Syahrullail ◽  
Jazair Yahya Wira ◽  
W.B. Wan Nik ◽  
Chiong Ing Tiong
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Palm Olein ◽  
Normal Load ◽  
Mineral Oil ◽  
Low Friction ◽  
Sliding Speed ◽  
Rbd Palm Olein

In this paper, the effect of sliding speed on the anti-friction of RBD palm olein was investigated using four-ball tribotester. The speeds were varied from 800 to 1400 rpm. The normal load was set to 40 kg and the test oil was heated up to 75 °C before the experiments. The result showed that palm olein has low friction coefficient compared to additive-free paraffinic mineral oil.

Transition of Wear Mechanisms of Plasma Source Nitrided AISI 316 Austenitic Stainless Steel Against Ceramic Counterface

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
G. Y. Li ◽  
Z. Y. Wang ◽  
M. K. Lei
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Normal Load ◽  
Plasma Source ◽  
Specific Wear Rate ◽  
Phase Layer ◽  
Sliding Speed ◽  
Aisi 316

A single high-nitrogen face-centered-cubic (f.c.c.) phase (γN) layer formed on the plasma source nitrided AISI 316 austenitic stainless steel at a nitriding temperature of 450 °C for a nitriding time of 6 h. An approximately 17 μm-thick γN layer has a peak nitrogen concentration of about 20 at. %. Tribological properties of the γN phase layer on a ball-on-disk tribometer against an Si3N4 ceramic counterface under a normal load of 2 and 6 N with a sliding speed of 0.15 to 0.29 m/s were investigated by friction coefficient and specific wear rate measurement. Worn surface morphology and wear debris were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The microhardness of the γN phase layer on the nitrided stainless steel was measured as about 15.1 GPa. The change in the friction coefficient of the γN phase layer on the stainless steel was dependent on the applied normal load, which was associated with that in the specific wear rate. Under a lower normal load of 2 N, the lower specific wear rate of the γN phase layer with a sliding speed of 0.15 m/s was obtained as 2.8 × 10−6 mm3/N m with a friction coefficient of 0.60. Under a higher normal load of 6 N, the lower specific wear rate with a sliding speed of 0.29 m/s was 7.9 × 10−6 mm3/N m with a friction coefficient of 0.80. When the applied load increased from 2 to 6 N, a transition of the wear mechanisms from oxidative to abrasive wear was found, which was derived from the oxidation reaction and the h.c.p. martensite phase transformation of the γN phase during the wear tests, respectively.

The Mechanical Properties and Friction and Wear Behavior of C/C-SIC

2010 ◽  
Author(s):  
Gao Wen ◽  
Chongsheng Long ◽  
Tang Rui ◽  
Jiping Wang
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Carbon Matrix ◽  
Specific Wear Rate ◽  
Sliding Speed ◽  
Wear Rates ◽  
Sic Composites

Carbon fiber reinforced carbon-silicon carbide composites (C/C-SiC) were prepared by chemical volume infiltration (CVI) method and reaction melt infiltration (RMI) technique of silicon liquid to carbon reinforce carbon matrix composites. The friction and wear behaviors of C/C-SiC composites at various loads and sliding speeds were investigated by MRH-3 block-on-ring tribometer at room temperature under water lubricating conditions. Furthermore, the morphologies, phase of the worn surface and the debris were observed, examined and analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) respectively. Experimental results showed that the C/C-SiC composites had a better wear resistence, and the friction coefficient under water lubricated conditions is about 0.02–0.06. The influence of sliding speed on the friction coefficients and the specific wear rate of C/C-SiC is more obvious than that of normal load when the load is less than 200N (inclueded200N). The friction coefficient and the specific wear rate of C/C-SiC decreased as the sliding velocity increased. At the sliding speed higher than 2m/s, the friction coefficient is less than 0.02. The specific wear rates is at a low level about (2×10−7mm3/Nm–5×10−8mm3/Nm).

Paper 19: Unlubricated Sliding at High Speeds between Copper and Steel Surfaces

1966 ◽  
Vol 181 (15) ◽  
pp. 25-30 ◽  
Author(s):  
M. J. Kadhim ◽  
S. W. E. Earles
Keyword(s):  
Oxide Layer ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Sliding Speed ◽  
Wear Rates ◽  
High Speeds ◽  
Before And After ◽  
The Coefficient Of Friction ◽  
Steel Disc ◽  
Steel Surfaces

Experiments are described in which stationary copper specimens are rubbed in a normal atmosphere against a rotating S62 steel disc under normal loads up to 4·5 lbf. The coefficient of friction is measured at sliding speeds of 93, 220, 328, and 490 ft/s using ⅛-in diameter specimens. Except at the lowest speed a gradual buildup of a continuous copper oxide layer on the disc track is observed with increasing normal load together with a corresponding decrease in the coefficient of friction. Having established an oxide layer on the track the coefficient of friction observed is low for all normal loads. The coefficient of friction is shown to decrease with normal load N and sliding speed U, to be a function of N1/2 U, and to depend on the state of the disc surface. Wear of -in diameter specimens is measured by weighing before and after a test. The wear rate is shown to decrease with sliding speed and increase with load, and for speeds of 220 and 328 ft/s to be a function of N/U. The wear rates measured at 93 ft/s are the same function of N/U for low values of N/U.

Metrological support and some results of pairs of cylindrical friction studies

2016 ◽  
Vol 6 (3) ◽  
pp. 177-183
Author(s):  
Серебрянский ◽  
Aleksey Serebryanskiy ◽  
Богатырева ◽  
Zhanna Bogatyreva
Keyword(s):  
Friction Coefficient ◽  
Metrological Support ◽  
Friction And Wear ◽  
Reliable Data ◽  
Linear Wear ◽  
Sliding Velocity ◽  
Sliding Speed

Proposed metrological support of the research of cylindrical pairs on friction and wear al-lows obtaining reliable data about real wear processes. Analysis of the types of wear and pre-sented studies results of specific linear wear of friction pairs with self-lubricating anti-friction plastics showed that an increase in the sliding speed and load - linear wear is reduced. The analy-sis on the influence of the static forces of friction coefficient shows that with load and sliding velocity increasing friction coefficient decreases in all the three cases

A STRATEGY TO ENHANCE THE BIOMEDICAL ARTICULATION SYSTEM BY ELECTROCHEMICALLY TEXTURING OF METAL SURFACES

2012 ◽  
Vol 24 (04) ◽  
pp. 343-347
Author(s):  
Ta-I Yang ◽  
Yi-Chun Chen ◽  
Huei-Ting Huang ◽  
I-Hsiang Tseng ◽  
Hsu-Wei Fang
Keyword(s):  
Friction Coefficient ◽  
Steel Surface ◽  
Electrochemical Etching ◽  
High Load ◽  
Stainless Steel Surface ◽  
Artificial Joint ◽  
Surface Wear ◽  
Textured Surfaces ◽  
Lower Load ◽  
Steel Surfaces

The concept of texturing steel surfaces were attempted to ease the surface wear and to prevent the release of harmful ions in the conventional joint replacement systems. The surfaces of the bio-compatible steels were textured by photolithography and electrochemical etching techniques to lower the friction coefficient and hence reduce the wear of the surface. Experimental results confirmed that the surfaces with textures (grooves) showed lower friction coefficient compared to un-textured surfaces at a high load (50 N). The friction coefficient could be further reduced for a lower load (10 N) through optimizing the generated hydrodynamic lift. A significant 47% reduction of friction coefficient was archived by tailoring the orientation and size of the textures on the stainless steel surface. The demonstrated strategy in this study would thus offer exciting avenues for developing artificial joint systems that last the full duration of the patients' life without any side-effect concerns.

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