The role of surface topography and normal load in the initiation of ratchetting-peak friction, seizure, scuffing, and elastic shakedown

2021 ◽  
pp. 1-12
Author(s):  
Vimal Edachery ◽  
V. Swamybabu ◽  
Gurupatham Anand ◽  
Paramasamy Manikandan ◽  
Satish V. Kailas

Abstract Surface topography is a critical parameter that can influence friction and wear in engineering applications. In this work, the influence of surface topography directionality on seizure and scuffing initiation during tribological interactions is explored. For this, unidirectional sliding wear experiments were carried out in immersed lubrication conditions for various normal loads. The tribological interactions were studied using EN31-60 HRC flats and SAE52100-60HRC pins in a sphere on flat configuration. The results show that, in some cases, the sliding interactions in the initial cycles lead to a high friction coefficient of up to ∼0.68 in lubricated conditions, which was termed as ‘peak friction’, and this was accompanied by scuffing. The existence of peak friction was found to be dependent on surface topography directionality, especially when the directionality in topography was parallel to the sliding direction. Continuous ratchetting was found to be the cause of peak friction which was accompanied by seizure and scuffing. When the topography directionality was perpendicular or independent of sliding direction, elastic shakedown occurred at earlier cycles and prevented peak friction initiation, scuffing and also facilitated for higher steady-state friction values.

1983 ◽  
Vol 105 (1) ◽  
pp. 36-41 ◽  
Author(s):  
R. Glardon ◽  
I. Finnie

Experimental investigations of the friction and wear of four copper alloys and pure nickel are presented. Measurements of the shape and dimensions of the wear tracks and of the extent of subsurface layers are also reported. The results are discussed in terms of mechanical behavior and possible correlations with conventional mechanical properties are considered. The role of cyclic plastic deformation is emphasized and areas of interest for future research are suggested.


2012 ◽  
Vol 591-593 ◽  
pp. 873-879
Author(s):  
Sheng Guan Qu ◽  
Guang Hong Wang ◽  
Li Kui Liu ◽  
Yong Hu ◽  
Xiao Qiang Li

Plasma nitriding technology was carried out on the surface of bearing steels. The phase composition and microhardness of the nitrided layer were analyzed. Sliding wear characteristics of the nitriding steel were studied on an Optimol SRV IV oscillating friction and wear tester at room temperature. The fretting wear mechanism was investigated with scanning electron microscopy (SEM) and 3D surface profiler. The results showed that Cr2N, Fe4N, Fe2 ~ 3N phases were observed on the nitrided surface layers; lubricating condition, normal load and friction velocity have great effect on the friction and wear characteristics of the plasma nitrided steels.


Tribologia ◽  
2017 ◽  
Vol 272 (2) ◽  
pp. 25-31
Author(s):  
Andrzej DZIERWA

Wear tests were conducted using a ball-on-disc tester T-11. In the experiment, a 42CrMo4 rotating steel disc with a hardness of 40±2 HRC was placed in contact with a 100Cr6 steel ball with a diameter of 6.35 [mm]. The hardness of the ball was set to 62±2 HRC. Finishing treatment applied to the surfaces was sand blasting. Disc samples were prepared to obtain surfaces in similar range of the Sa parameter (arithmetical mean height of the surface) but other surface topography parameters vary. Dry sliding tests were conducted at sliding speeds of v1 = 0.16; v2 = 0.24 i v3 = 0.32 [m/s]. The sliding distance was set to 282.6 [m], and the normal load was set to 9.81 [N]. During the tests, the friction force was monitored as a function of time. Disc and ball wear was measured after the tests using a white light interferometer Talysurf CCI Lite. Profiles were taken in four positions (900 apart) perpendicular to the wear track. Then, using an interferometer software program TalyMap Gold 6.0, they were computed and averaged. It was found that the initial surface topography has a significant influence on friction and wear levels under dry sliding conditions. It was also identified the correlation between several surface topography parameters and wear volume.


2012 ◽  
Vol 585 ◽  
pp. 569-573 ◽  
Author(s):  
S.R. Chauhan ◽  
Sunil Thakur

In this paper the friction and wear characteristics of vinylester and vinylester composites have been investigated under dry sliding conditions for different applied normal load, sliding speed and sliding distance. The experiments have been carried on a pin on disc arrangement at normal room temperature conditions. The influence of friction and wear parameters like normal load, speed, sliding distance and percentage of filler content on the friction and wear rate has been investigated. In this study, a plan of experiments based on the techniques of Taguchi was performed to acquire data in a controlled way. An orthogonal array L27 (313) and Analysis of variance (ANOVA) were applied to investigate the influence of process parameters on the coefficient of friction and sliding wear behaviour of these composites. The Taguchi design of experiment approach eliminates the need for repeated experiments and thus saves time, material and cost. The results showed that with increase in the applied normal load and sliding speed the coefficient of friction and specific wear rate decreases under dry sliding conditions. It is also found that a thin film formed on the counterface seems to be effective in improving the tribological characteristics. The results showed that the inclusion of cenosphere as filler materials in vinylester composites will increase the wear resistance of the composite significantly.


2013 ◽  
Vol 1505 ◽  
Author(s):  
Emil J. Sandoz-Rosado ◽  
Elon J. Terrell

ABSTRACTIn this study, the failure mechanisms of graphene under sliding are examined using atomistic simulations. A 6nm diameter diamond tip is slid (at a controlled normal load) over a graphene monolayer that is adhered to a semi-infinite silicon substrate. The impact of tip adhesion on the wear and frictional behavior of graphene is studied by comparing two diamond tips, one of which has been hydrogen-passivated and the other which is bare carbon. By contrasting the passivated and unpassivated tips, the interplay of adhesive and abrasive wear on the graphene membrane can also be compared. The results of this work indicate that chemical bonding between the tip and the graphene greatly exacerbates tearing in the graphene monolayer by plowing ahead of the indenter, causing material build-up and increasing effective contact area.


Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Y. Sasidhar ◽  
Satish V. Kailas

Tribological interaction between two contacting surfaces is influenced by many factors such as relative motion, normal load, environment, and lubrication apart from surface characteristics of the mating surfaces. Though surface characteristics such as roughness was dealt by many researchers for decades, the other important characteristic of surfaces, surface topography, has not got its share of attention. In the present investigation, basic studies were conducted using Inclined Scratch Tester to understand the role of surface topography on friction and transfer layer formation. A tribological couple made of copper pin against EN8 flat was used in the tests. Two surface parameters of steel flats — roughness and texture — were varied in tests. Care was taken to ensure that the surface roughness, measured along the scratch direction, had similar values for different textures, namely Unidirectional, 8-ground, and Random. It was observed that the transfer layer formation and the coefficient of friction along with its two components, namely adhesion and plowing, are controlled by the nature of surfaces and are independent of surface roughness. The plowing component of friction was highest for the surface that promotes plane strain conditions near the surface and was lowest for the surface that promotes plane stress conditions near the surface.


1984 ◽  
Vol 106 (1) ◽  
pp. 54-58 ◽  
Author(s):  
V. Aronov ◽  
A. F. D’Souza ◽  
S. Kalpakjian ◽  
I. Shareef

Dry frictional contact between two metallic surfaces, one cast iron and the other steel, is analyzed. The experiments were conducted using a pin-on-disk setup instrumented with force and acceleration transducers. The interactions between friction, wear, and vibrations and their dependence on normal load and system stiffness are investigated. The results indicate that stiffness has a significant effect on the normal load at which transition takes place from mild to severe friction and wear. The variation of surface roughness with normal load for different stiffnesses is also examined. The different regimes of friction are observed, as the normal load is increased. They are characterized as steady state friction region, nonlinear friction region, region of transient friction with disturbances and region of self-excited vibrations. It is shown that the transition from the steady-state friction can be characterized by a sudden increase in the coefficient of friction and amplitude of slider oscillations.


Friction ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1-28
Author(s):  
Lei Chen ◽  
Linmao Qian

Abstract Surficial water adsorption and interfacial water condensation as natural phenomena that can alter the contact status of the solid interface and tribological performances are crucial in all length scales, i.e., from earthquakes to skating at the macroscale level and even to micro/nano-electromechanical systems (M/NEMS) at the microscale/nanoscale level. Interfacial water exhibits diverse structure and properties from bulk water because of its further interaction with solid surfaces. In this paper, the evolutions of the molecular configuration of the adsorbed water layer depending on solid surface chemistry (wettability) and structure, environmental conditions (i.e., relative humidity and temperature), and experimental parameters (i.e., sliding speed and normal load) and their impacts on tribological performances, such as adhesion, friction, and wear, are systematically reviewed. Based on these factors, interfacial water can increase or reduce adhesion and friction as well as facilitate or suppress the tribochemical wear depending on the water condensation kinetics at the interface as well as the thickness and structure of the involved interfacial water.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3074
Author(s):  
Kaveh Torkashvand ◽  
Vinod Krishna Selpol ◽  
Mohit Gupta ◽  
Shrikant Joshi

Sliding wear performance of thermal spray WC-based coatings has been widely studied. However, there is no systematic investigation on the influence of test conditions on wear behaviour of these coatings. In order to have a good understanding of the effect of test parameters on sliding wear test performance of HVAF-sprayed WC–CoCr coatings, ball-on-disc tests were conducted under varying test conditions, including different angular velocities, loads and sliding distances. Under normal load of 20 N and sliding distance of 5 km (used as ‘reference’ conditions), it was shown that, despite changes in angular velocity (from 1333 rpm up to 2400 rpm), specific wear rate values experienced no major variation. No major change was observed in specific wear rate values even upon increasing the load from 20 N to 40 N and sliding distance from 5 km to 10 km, and no significant change was noted in the prevailing wear mechanism, either. Results suggest that no dramatic changes in applicable wear regime occur over the window of test parameters investigated. Consequently, the findings of this study inspire confidence in utilizing test conditions within the above range to rank different WC-based coatings.


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