Specific Heat of Tribological Wear Debris Material

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Maria Maciąg
Keyword(s):  
Specific Heat ◽  
Thermodynamic Model ◽  
Wear Debris ◽  
Friction And Wear ◽  
Mass Conservation ◽  
Phenomenological Approach ◽  
Wear Testing ◽  
Physical Parameters ◽  
Friction Process ◽  
Solid Friction

Stationary processes of solid friction, heating and wear are analyzed in this paper on the basis of the first principle of thermodynamics. Analytical dependences between physical parameters of a tribological system have been determined. Densities of extensive quantity fluxes are referred to elementary surface and elementary time, which has permitted to include intensive quantities, especially temperature, in the model presented here. Although the discussion is restricted to the phenomenological approach, conclusions regarding some microscopic properties of the matter in the process of fragmentation are drawn directly from the laws of energy and mass conservation. Differences between specific heat of the starting material cp and of the debris produced cp′ are emphasized. The model of the friction process described by Maciąg, M. (2010, “Thermodynamic Model of the Metallic Friction Process,” ASME J. Tribol., 132(3), pp. 1–7) has been modified and a new method of evaluating cp′ is proposed. Results of standard friction and wear testing are used to describe selected tribological systems in quantitative terms based on the thermodynamic model discussed here (Sadowski, J., and Żurowski, W., 1992, “Thermodynamic Aspects of Metals' Wear-Resistance,” Tribol. Lubr. Eng., 3, pp. 152–159). Very high specific heat of tribological wear debris material is found at the moment of the material's production. To conclude, results of theoretical and experimental analysis are discussed and their interpretation is proposed. Applicability of the system magnitudes C and D to modeling of friction and wear is highlighted.

The friction and wear behaviors of polyimide bearing retainer under point-contact condition

2020 ◽  
Vol 72 (7) ◽  
pp. 931-936
Author(s):  
Yafeng Zhang ◽  
Shaohua Zhang ◽  
Gang Zhou ◽  
Jiang Zhang ◽  
Tao Qing ◽  
...  
Keyword(s):  
Peer Review ◽  
Wear Debris ◽  
Friction And Wear ◽  
Testing Machine ◽  
Point Contact ◽  
Contact Condition ◽  
Wear Testing ◽  
Sliding Velocity ◽  
Content Type ◽  
Polyimide Composites

Purpose Random point-contact between the space bearing retainer and the rolling elements may cause wear of the space bearing retainer. The paper aims to clarify the friction and wear behaviors of polyimide bearing retainer under point-contact condition. Design/methodology/approach Space bearing retainers were cut into flat specimens and the tribological behaviors of the specimens were studied under point-contact condition using a friction and wear testing machine. Different sliding velocities and normal loads were used to simulate the running state of space bearing retainer. The wear behaviors of the space bearing retainer were analyzed by SEM and white light interferometer. Findings The friction coefficient of the polyimide composites decreased with increase in sliding velocity from 1  to 5 mm/s. Moreover, with increase in sliding velocity and normal load, the wear rate of the polyimide composites decreased and increased, respectively. Moreover, the wear behaviors of the polyimide composites were mainly determined by the combined actions of ploughing friction and adhesive friction. The lubricating properties of transfer film and wear debris were limited under point-contact condition. Practical implications The paper includes implications for the understanding of the wear mechanism of the polyimide composites space bearing retainer under point-contact condition and then to optimize space bearing retainer materials further. Originality/value Under point-contact condition, wear debris can hardly participate in the friction process because of limited contact area. Consequently, the wear debris has limited impact on the wear process to decrease the friction and wear. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0017/

ANALYSIS OF THE RANGE OF THE SPECIFIC HEAT OF TRIBOLOGICAL WEAR PRODUCTS

Tribologia ◽  
2019 ◽  
Vol 287 (5) ◽  
pp. 51-57
Author(s):  
Maria MACIĄG
Keyword(s):  
Specific Heat ◽  
Friction And Wear ◽  
Energy Balance Equation ◽  
Maximum Heat ◽  
Friction Process ◽  
Wear Product ◽  
Tribological System ◽  
Wear Products ◽  
Friction Parameters ◽  
Very High

This paper continues a discussion of specific heat cp’ of wear product material at the time of the products’ generation which was initiated in [L. 2]. The very high values of this quantity found on the basis of the laws of mass and energy conservation have inspired further analyses to possibly validate the results. System quantities C and D [L. 2] have played central roles in earlier modelling of the friction and wear of solids. They are determined for a certain range of the temperature of a macroscopic contact of solids Θ and serve the purpose of a merely approximate estimation of minimum cp’. An attempt at determining real values of cp’ for specific Θ without taking C and D into consideration has been undertaken in this study. The discussion was based on the energy balance equation for the stationary friction process which is associated with wear. The significance of friction parameters, the physical properties of a material subject to friction, and some characteristics of the tribological system have been emphasised. The analysis is also designed to determine maximum heat, cp’max, and a range of its variations, cp’min - cp’max. The resultant analytical dependences that characterise friction and its effects are illustrated with examples of selected experiments [L. 10], which were originally designed to estimate values of cp’ [L. 2]. The evaluation of cp’ discovers negligible differences between cp’ and cp’min. Important information has additionally been acquired about the values of the flash temperature, Θo, and its relations to temperature D. No regular impact of on the specific heat of wear products has been determined.

Tribological effects of laser surface texturing and residual stress

2018 ◽  
Vol 70 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Shuwen Wang ◽  
Feiyan Yan ◽  
Ao Chen
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Friction And Wear ◽  
Surface Texturing ◽  
Laser Surface ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Wear Testing ◽  
Content Type ◽  
Surface Textures

Purpose The purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces. Design/methodology/approach Three different surface textures (circular dimple, elliptical dimple and groove) with two different textured area ratios (10 and 20 per cent) are designed and fabricated by a Picosecond Nd YAG Laser machine. The friction and wear performance of textured specimens is tested using a UMT-2 friction and wear testing machine in mixed lubrication. Findings Test results show that elliptical dimples exhibit the best performance in wear resistance, circular dimples in friction reduction and grooves in stabilization of friction. The surfaces with larger textured area density exhibit better performance in both friction reduction and wear resistance. The improved performance of LST is the coupled effect of surface texture and residual stress. Originality/value The findings of this study may provide guidance for optimal design of functional surface textures in reciprocating sliding contacts under mixed or hydrodynamic lubrication, which can be used in automotive and other industrial applications.

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.

Influence of Liquid Paraffins in Crude Oil on the Friction and Wear Behaviors of the Progressing Cavity Pump`s Stator Rubber

2013 ◽  
Vol 300-301 ◽  
pp. 833-836
Author(s):  
Shi Jie Wang ◽  
Hao Lin ◽  
Xiao Ren Lv
Keyword(s):  
Crude Oil ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Liquid Paraffin ◽  
Testing Machine ◽  
Wear Testing ◽  
Wear Loss ◽  
Oil Well ◽  
Butadiene Rubber ◽  
Better Than

The progressing cavity pump (PCP) always works in the waxy oil well. Therefore the research on the influence of various liquid paraffin contents in crude oil on the friction and wear behaviors of the progressing cavity pump`s stator is very important for choosing the best stator rubber and developing the service life of PCP. Wear behavior of nitrile butadiene rubber (NBR) and fluororubber (FKM) was investigated at room temperature using a reciprocating friction and wear testing machine under the various paraffin contents in crude oil (0%、10%、30%、50%、100%). The wear morphology of blend was analyzed through the stereomicroscope and the wear behavior of two blends was also discussed and compared. The results show that the wear resistance of FKM is better than that of NBR under the same paraffin content in crude oil; With the increase of the paraffin content, the wear and coefficient of friction also increase. When the paraffin content in crude oil is less than 30%, the wear loss of NBR and FKM are basically the same; When the paraffin content in crude oil is more than 30%, the wear loss of NBR is far more than that of FKM.

Friction and wear testing with the modern four-ball apparatus

Wear ◽  
1971 ◽  
Vol 17 (5-6) ◽  
pp. 381-388 ◽  
Author(s):  
E.D. Brown
Keyword(s):  
Friction And Wear ◽  
Wear Testing

Chapter 37—Lubricant Friction and Wear Testing

2008 ◽  
pp. 1017-1017-26
Author(s):  
GE Totten ◽  
SR Westbrook ◽  
RJ Shah ◽  
M Anderson ◽  
FE Schmidt
Keyword(s):  
Friction And Wear ◽  
Wear Testing
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