Investigation of wear mechanism of forged steel piston skirt under boundary lubricated conditions

2018 ◽  
Vol 70 (7) ◽  
pp. 1303-1309
Author(s):  
Zhang Jian ◽  
Deng Lijun ◽  
Hao Guannan ◽  
Liu Shiying
Keyword(s):  
Surface Roughness ◽  
Wear Mechanism ◽  
Boundary Lubrication ◽  
Normal Load ◽  
Testing Machine ◽  
Wear Model ◽  
Content Type ◽  
Piston Skirt ◽  
Steel Piston ◽  
Lubrication Conditions

Purpose With the implementation of new emission standards, the thermal–mechanical coupling load of engine pistons becomes more important. In this case, forged steel material with higher fatigue limit and impact resistance has been applied gradually in piston manufacturing. However, new failure problems emerge, and the wear of skirt under boundary lubrication conditions is an essential problem which needs to be solved urgently. Design/methodology/approach In this research, the abrasion testing machine was used to simulate the wear behavior under different conditions of normal pressure, relative velocity and surface roughness. Besides, the wear morphology was observed by scanning electron microscope. Then, the wear model was established by using test results fitting method, offering a way to conduct qualitative analysis for the wear problem under the same conditions. Findings The results show that mainly the wear mechanism of the piston skirt under boundary lubricated conditions is adhesive wear and abrasive wear. In addition, the coefficient and wear rate will increase with the increase in the normal load and surface roughness and decrease with the increase in the relative speed. In the wear model, the wear loss is mainly influenced by the normal load, the relative sliding speed and the wear time. Originality/value The wear degree of piston skirt was qualitatively obtained in this investigation by factors such as pressure, velocity and so on, and the wear mechanism of forged steel piston skirt under boundary lubrication conditions was also determined. These could provide theoretical support for further optimization of cylinder motion and oil supply system, reduction of friction loss and power loss.

Measurement of roller chain wear lubricated with palm oil-based hexagonal boron nitride nanoparticles

2020 ◽  
Vol 72 (10) ◽  
pp. 1199-1204
Author(s):  
Hilmi Amiruddin ◽  
Mohd Fadzli Bin Abdollah ◽  
Muhamad Aliff Danial Mohamad Nizar
Keyword(s):  
Boron Nitride ◽  
Palm Oil ◽  
Wear Mechanism ◽  
Hexagonal Boron Nitride ◽  
Wear Performance ◽  
Content Type ◽  
Roller Chain ◽  
Resistance Torque ◽  
Torque Values ◽  
Lubrication Conditions

Purpose This study aims to introduce a novel technique which helped in quantifying the wear performance of a roller chain which was lubricated by using the palm oil-based hexagonal boron nitride (hBN) nanoparticles (nano-biolubricant). Design/methodology/approach The efficiency of the nano-biolubricant was evaluated by using a custom-made roller chain tribometer, at different resistance torque values at a constant speed and running time. Prior to the test, 2 different lubrication conditions were applied. The mass loss and elongation behaviour of a roller chain was selected as a degradation metric for monitoring the amount of the chain wear. The predominant wear mechanism of a roller chain was identified by surface morphological analysis. Findings Regardless of the lubrication conditions, the wear performance of the roller chain was significantly increased, at increasing resistance torque values. Higher wear was noted when the roller chain was lubricated using a nano-biolubricant, however, the wear curve showed a promising high chain life. The predominant wear mechanism involved is abrasive wear. Originality/value Although an increase in the elongation during running is based on the wear between the pins and roller, none of the earlier studies quantified the wear performance of a roller chain under differing lubrication conditions. Hence, for bridging the gap, this study described a new method for measuring the wear performance of the roller chain which was lubricated using the palm oil-based hBN nanoparticles or a nano-biolubricant. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0061/

Tribological evaluation of piston skirt/cylinder liner contact interfaces under boundary lubrication conditions

2010 ◽  
Vol 22 (3) ◽  
pp. 73-87 ◽  
Author(s):  
Nicholaos G. Demas ◽  
Robert A. Erck ◽  
George R. Fenske
Keyword(s):  
Boundary Lubrication ◽  
Cylinder Liner ◽  
Piston Skirt ◽  
Lubrication Conditions

Contribution of roughness parameters in the scuffing performance of metallic surfaces

2017 ◽  
Vol 69 (4) ◽  
pp. 507-515 ◽  
Author(s):  
Lukasz Wojciechowski ◽  
Radomir Majchrowski ◽  
Thomas G. Mathia
Keyword(s):  
Boundary Lubrication ◽  
Three Dimensional ◽  
Evaluation Study ◽  
Statistical Correlation ◽  
Morphological Parameters ◽  
Metallic Surfaces ◽  
Double Blind ◽  
Content Type ◽  
Lubrication Conditions

Purpose Boundary lubrication cannot provide long-term protection against scuffing. Therefore, it is fundamental to recognise the breaking point of the boundary layer that activates scuffing. Based on this assumption, three-dimensional (3D) morphologies of surfaces were characterised, and the fundamental conditions of the scuffing process were investigated to identify the transition from boundary lubrication conditions to catastrophic wear. Design/methodology/approach A series of systematic tribological double-blind experiments were carried out using a poorly lubricated cylinder/plane interface to model the tribological inverse problem in a boundary lubrication situation. Areal morphological analysis was performed, with the help of an optical interferometer, on a millimetric area corresponding to the contact surface during experimental tribological investigations. The statistical correlation between scuffing and the selected morphological parameters was evaluated. This evaluation study consisted of determining the linear, logarithmic, exponential, polynomial (of degree 2) or power dependency between time to scuffing and morphological parameters. Findings A clear, statistically confirmed relationship was observed between selected morphological parameters of the surface (Spd, Sha, Str, Sz) and its scuffing performance. Originality/value 3D morphological parameters that best specified the technological scuffing performance of metallic surfaces were selected and proposed.

scholarly journals Theoretical and Experimental Investigation on Friction in Lubricated Line Contacts with Different Materials and Textures in Presence of Wear

2016 ◽  
Vol 681 ◽  
pp. 142-154 ◽  
Author(s):  
Francesca Di Puccio ◽  
Enrico Ciulli
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Friction Coefficient ◽  
Boundary Lubrication ◽  
Flat Surface ◽  
Surface Conditions ◽  
Lubrication Regimes ◽  
Line Contacts ◽  
Lubrication Conditions ◽  
Theoretical Procedure

An experimental investigation on the friction coefficient in line contacts under mixed and boundary lubrication regimes is described. Rectangular contacts between cylindrical specimens and the flat surface of discs of different material and surface roughness combinations were analyzed. Very low Stribeck numbers have been considered, resulting also in low dimensionless film thickness, so that the morphology of the surfaces and the material had a remarking role. In this work, the theoretical procedure for assessing the friction coefficient in the tested cases is described and compared to experimental results. Additionally, wear effects obtained in boundary lubrication conditions are shown. The surface conditions are put in relation with some particular trends of the friction coefficient obtained for certain combinations of materials and roughness.

Numerical investigation of sliding friction behaviour and mechanism of engineering surfaces

2019 ◽  
Vol 71 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Xiaogang Zhang ◽  
Yali Zhang
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Sliding Friction ◽  
Normal Load ◽  
Numerical Results ◽  
Operating Conditions ◽  
Friction Mechanism ◽  
Content Type ◽  
Optimal Surface ◽  
Friction Behaviour

Purpose This study aims to investigate the sliding friction behaviour and mechanism of engineering surfaces. Design/methodology/approach A new numerical approach is proposed. This approach derives the macroscale friction coefficient from microscale asperity interactions. By applying this approach, the sliding friction behaviour under different operating conditions were investigated in terms of molecular and mechanical components. Findings Numerical results demonstrate an independent relationship between normal load and friction coefficient, which is governed by the saturated plastic ratio. Numerical results also demonstrate that under very small load, an increase in load increases the friction coefficient. In addition, numerical results confirm the existence of optimal surface roughness where the friction coefficient is the lowest. For the surface profiles used in the current calculation, an optimal surface roughness value is obtained as Rq = 0.125 μm. Originality/value This new approach characterizes the deterministic relationship between macroscale friction coefficient and microscale asperity molecular/mechanical interactions. Numerical results facilitate the understanding of sliding friction mechanism.

Static Friction of Contacting Real Surfaces in the Presence of Sub-Boundary Lubrication

1998 ◽  
Vol 120 (2) ◽  
pp. 296-303 ◽  
Author(s):  
A. A. Polycarpou ◽  
Izhak Etsion
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Film Thickness ◽  
Boundary Lubrication ◽  
Normal Load ◽  
Static Friction ◽  
Liquid Films ◽  
Adhesion Forces ◽  
Static Friction Coefficient ◽  
Magnetic Hard Disk

A model for calculating the static friction coefficient of contacting real (rough) surfaces in the presence of very thin liquid films (sub-boundary lubrication) is developed. The liquid has a very high affinity for the surfaces and its thickness is of the order of the surface roughness average. An extension of the Greenwood and Williamson (GW) asperity model and an improved Derjaguin, Muller and Toporov (DMT) adhesion model are utilized for calculating the contact and adhesion forces, respectively. The effects of the liquid film thickness and the surface topography on the static friction coefficient are investigated. A critical film thickness is found above which the friction coefficient increases sharply. The critical thickness depends on the surface roughness and the external normal load. This phenomenon is more profound for very smooth surfaces and small normal loads, in agreement with published experimental work on magnetic hard disk interfaces.

Micro/nanotribology using atomic force microscopy/friction force microscopy: State of the art

1998 ◽  
Vol 212 (1) ◽  
pp. 1-18 ◽  
Author(s):  
B Bhushan
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Friction Force ◽  
Boundary Lubrication ◽  
Normal Load ◽  
Atomic Scale ◽  
Friction Force Microscopy ◽  
Material Transfer ◽  
Force Microscopy ◽  
Atomic Force

Atomic force microscopy/friction force microscopy (AFM/FFM) techniques are increasingly used for tribological studies of engineering surfaces at scales ranging from atomic and molecular to microscales. These techniques have been used to study surface roughness, adhesion, friction, scratching/wear, indentation, detection of material transfer and boundary lubrication and for nanofabrication/nanomachining purposes. Micro/nanotribological studies of materials of scientific and engineering interest have been conducted. Commonly measured roughness parameters are found to be scale dependent, requiring the need of scale-independent fractal parameters to characterize surface roughness. Measurement of atomic-scale friction of a freshly cleaved highly orientated pyrolytic graphite exhibited the same periodicity as that of corresponding topography. However, the peaks in friction and those in corresponding topography were displaced relative to each other. Variations in atomic-scale friction and the observed displacement have been explained by the variations in interatomic forces in the normal and lateral directions. Local variation in microscale friction is found to correspond to the local slope, suggesting that a ratchet mechanism is responsible for this variation. Directionality in the friction is observed on both micro- and macroscales which results from the surface preparation and anisotropy in surface roughness. Microscale friction is generally found to be smaller than macroscale friction as there is less ploughing contribution in microscale measurements. Microscale friction is load dependent and friction values increase with an increase in the normal load, approaching the macrofriction at contact stresses higher than the hardness of the softer material. The wear rate for single-crystal silicon is negligible below 20 μN and is much higher and remains approximately constant at higher loads. Elastic deformation at low loads is responsible for negligible wear. The mechanism of material removal on a microscale is studied. At the loads used in the study, material is removed by the ploughing mode in a brittle manner without much plastic deformation. Most of the wear debris is loose. Evolution of the wear has also been studied using AFM. Wear is found to be initiated at nanoscratches. AFM has been modified to obtain load-displacement curves and for measurement of nanoindentation hardness and Young's modulus of elasticity, with the depth of indentation as low as 1 nm. Hardness of ceramics on the nanoscale is found to be higher than that on the microscale. Ceramics exhibit significant plasticity and creep on the nanoscale. Scratching and indentation on nanoscales are powerful ways to screen for adhesion and resistance to deformation of ultra-thin films. Detection of material transfer on the nanoscale is possible with AFM. Boundary lubrication studies and measurement of lubricant-film thickness with a lateral resolution on a nanoscale have been conducted using AFM. Self-assembled monolayers and chemically bonded lubricant films with a mobile fraction are superior in wear resistance. Friction and wear on micro- and nanoscales at low loads have been found to be generally smaller compared to that at macroscales. Therefore, micro/nanotribological studies may help define the regimes for ultra-low friction and near-zero wear.

The influence of surface roughness and viscosity on micropitting damage

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Li ◽  
Liantao Lu
Keyword(s):  
Surface Roughness ◽  
Boundary Lubrication ◽  
Design Methodology ◽  
Wear Loss ◽  
Range Analysis ◽  
Heavy Load ◽  
Content Type ◽  
Two Factors ◽  
Lubrication Condition ◽  
Laser Confocal Microscope

Purpose This study aims to investigate the influence of surface roughness and viscosity on micropitting and their influence sequence. Design/methodology/approach Specimens were made of carburized and quenched 18CrNiMo7-6, and different surface roughness was obtained by grinding and shot peening. Tests were carried out on a rolling-sliding tribometer, with different viscosity lubricants and a heavy load under a boundary lubrication condition. The laser confocal microscope was used to measure the aspects, surface roughness, profiles in the contacted region and micropitting damage percentage. A factorial experiment was designed, and the range analysis was applied to find the sequence of influence of surface roughness and viscosity. Findings The result shows that surface roughness has a more noticeable influence since the change of viscosity cannot generate sufficient wear loss to suppress micropitting. Originality/value The influence sequence of two factors on micropitting was investigated and the reason for the distribution was analyzed.

Study on Wear Model and Adhesive Wear Mechanism of Brass under Boundary Lubrication

2021 ◽  
Vol 57 (2) ◽  
pp. 367-373
Author(s):  
Lin Liu ◽  
Chao Yang ◽  
Jianzhong Zhou ◽  
Hamid Garmestani ◽  
Davoud Dastan
Keyword(s):  
Wear Mechanism ◽  
Boundary Lubrication ◽  
Adhesive Wear ◽  
Wear Model

Tribological properties of Fe-Cr-B alloy for sliding boot in coal mining machine under dry sliding condition

2017 ◽  
Vol 69 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Hongbin Xuan ◽  
Gongjun Cui
Keyword(s):  
Coal Mining ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Normal Load ◽  
Mining Machine ◽  
Dry Sliding ◽  
Wear Resistant ◽  
Content Type ◽  
Wear Rates ◽  
1045 Steel

Purpose To improve the wear resistance of the sliding boot, the wear-resistant Fe-21 Wt.% Cr-5 Wt.% B alloy is prepared, and the wear mechanism is studied under dry sliding condition. Design/methodology/approach The anti-wear Fe-21 Wt.% Cr-5 Wt.% B alloy is prepared by powder metallurgy technique. The tribological behavior of Fe-Cr-B alloy sliding against ASTM 1045 steel pin is studied at 30-60 N and 0.03-0.12 m/s using a reciprocating pin-on-disk tribometer under dry sliding condition. Meanwhile, the ASTM 5140 and 3316 steel are studied as compared samples. Findings The friction coefficients of tested specimens increase with the increasing normal load. However, this effect is the opposite in case of different sliding speeds. The specific wear rates increase as the sliding speed and normal load increase. The Fe-Cr-B alloy shows the best tribological properties under the dry sliding condition and the wear mechanism is mainly ploughing. Originality/value This wear-resistant Fe-21 Wt.% Cr-5 Wt.% B alloy can replace the traditional materials to process the sliding shoes and improve the service life of coal mining machine.

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