Proposal of invariant precursors for boundary lubricated scuffing

Wojciechowski, Łukasz; Mathia, T.

doi:10.1016/j.wear.2015.05.007

Cited by 15 publications

(15 citation statements)

References 21 publications

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“…The impact of rheological properties in terms of elasto-plastic behaviour of contacting bodies via residual stresses has been treated in previous papers showing clearly that the increase of the compressive residual stresses causes the increase of the scuffing performance [2,3]. The present paper is focused on morphological and physicochemical features of contacting surface's layer.…”

Section: Introductionmentioning

confidence: 95%

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Roughness and wettability of surfaces in boundary lubricated scuffing wear

Wojciechowski

Kubiak

Mathia

2016

Tribology International

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The diversity of multidisciplinary approaches suggests that fundamentals of scuffing require systemic, complex multi-scale and multi-physics analysis of an irreversible process as it is postulated in present study. That is probably one of the reasons of lack of unequivocal model of this irreversible transitional process from stable more or less lubricated wear to scuffing described only by one or few authors in equation(s) form. Therefore, it is useful to characterize the tribological surface properties in frame of systemic approach looking simultaneously for the optimal compromise between rheological, morphological and physicochemical features of contacting surface's layer. Hypothetical role connected to any group of features in the topological approach is elucidated and experimentally confirmed via the wettability, strongly combined with surface roughness and surface free energy. Due to the fact that the free energy is directly related to the surface wettability it can as well affect the scuffing activation process. For scientific and rhetoric reasons some selected results of limited boundary lubrication investigations under double blind trial conditions in case of gear oil with anti-wear (AW) and extreme pressure (EP) additives are elucidated here. The results issued from scuffing tests on AISI 4140 ground steel burnished under different forces in order to generate different surface roughness, residual stresses and surface energy are analysed. It was stated and numerically correlated that the wettability by lubricating medium influences the scuffing resistance. Additionally, the dependence of wettability on selected parameters of roughness and a time to scuffing activation have been stated. On that basis, it is proposed to reinforce concept of "oleophilic" and "oleophobic" properties of metallic surfaces as autonomous invariants determining the activation of catastrophic wear process under boundary lubricated conditions. Keywords: Scuffing; Wettability; Boundary lubrication; Surface roughness. This is an eprint of paper published by Elsevier in Tribology International (2015) kris@kubiak.co.uk http://dx Nomenclature:

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Section: Introductionmentioning

confidence: 95%

“…3. The impact of morphological properties of manufactured surfaces of contacting bodies via 3D systematic before tribological experimental investigations has been treated in previous papers showing clearly the ways to identify invariant of scuffing process [3].…”

Section: Introductionmentioning

confidence: 99%

Roughness and wettability of surfaces in boundary lubricated scuffing wear

Wojciechowski

Kubiak

Mathia

2016

Tribology International

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“…Therefore, assuming that it is impossible to recognise a universal mechanism of SP initiation, it seems to be very important to propose a general procedure for the technological creation of surfaces resistant to scuffing. Previous investigations from authors (Wojciechowski and Mathia, 2015a;2015b;2015c;Wojciechowski et al, 2016;2015;Wojciechowski and Mathia, 2015d) indicated the necessity of a topological approach to this problem, in which the dominant role is played by the interaction between the rheological, morphological and physicochemical properties of contacting surfaces. Particularly important here is the fact that the surface morphology can directly affect its physicochemical properties (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Particularly important here is the fact that the surface morphology can directly affect its physicochemical properties (e.g. via its wettability Wojciechowski and Mathia, 2015a;2015b;Wojciechowski et al, 2016;Kubiak et al, 2011a;Wojciechowski and Nosal, 2010) and indirectly its rheological properties (oil capacity and the pressures at its asperities Wojciechowski and Mathia, 2015c;2015d). Therefore, to investigate the importance of morphology in the technological creation of improved scuffing performance is a basic aim of these investigations.…”

Section: Introductionmentioning

confidence: 99%

Contribution of roughness parameters in the scuffing performance of metallic surfaces

Wojciechowski

Majchrowski

Mathia

2017

ILT

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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.

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“…As long as the volume of the pockets ensures the storage or leading out of wear debris, the flow of oil in the contact zone remains unthreatened. However, if the volume of the pockets is not able to accommodate a larger quantity of debris, this debris will accumulate in the contact zone [16]. Consequently, the oil flow will be disturbed and the scuffing process will be activated.…”

Section: Introductionmentioning

confidence: 99%