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Some Comments on the Interpretation of the Tribological Wear Coefficient

Sadowski Jan

Tribologia

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2021

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nr 2

45--56

EN

An original model of tribological wear is presented, an alternative to the commonly used J.F. Archard’s model. The impossibility is established of a full conversion of mechanical work into the heat of dissipation and thereby of avoiding wear in the sliding friction of solids. The assumption is consequently questioned that only some contacts of surface asperities are subject to temporary wear. Material wastage is assumed to occur at each contact of asperities. The volume of worn material is dependent on the volumetric wear coefficient of the “energy dissipation zone” in friction. The dimensions of the zone are determined in both the elements in friction. Linear wear intensities and volumetric wear are described in analytical terms. The thermodynamic analysis of the tribological process indicates some limitations to these intensities. Energetic efficiencies of solid wear and heating as a result of friction are defined. Some new interpretations of the wear coefficient are proposed.

PL

W pracy przedstawiono oryginalny model zużywania tribologicznego alternatywny do powszechnie stosowanego modelu J.F. Archarda. Stwierdzono niemożliwość zupełnej zamiany pracy mechanicznej na ciepło dyssypacji i tym samym uniknięcia zużycia przy tarciu ślizgowym ciał stałych. Na tej podstawie zakwestionowano słuszność założenia, że tylko część styków nierówności powierzchni podlega doraźnemu zużywaniu. Przyjęto, że ubytki materiału występują w każdym styku nierówności. Objętość startego materiału uzależniono od współczynnika zużycia i objętości tak zwanej strefy dyssypacji energii podczas tarcia. Ustalono wymiary tej strefy w obu trących się elementach. Opisano analitycznie liniowe intensywności zużywania i zużycie objętościowe. Przeprowadzona analiza termodynamiczna procesu tribologicznego wykazała istnienie ograniczeń tych intensywności. Określono sprawności energetyczne zużywania i nagrzewania ciał stałych wskutek tarcia. Przedstawiono nowe interpretacje współczynnika zużycia.

2

Structure and properties of aluminium-silicon matrix composites manufactured by pressure infiltration method

Kremzer M., Dobrzański L., Dziekońska M., Radziszewska A.

Archives of Materials Science and Engineering

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2014

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Vol. 68, nr 2

53--58

EN

Purpose: The goal of the paper is to develop technologies for manufacturing composite materials with casting aluminum alloy matrix reinforced by silicon AN AC-AlSi12 and to investigate the effect of the amount of the pore forming agent in the form of graphite MG 192 on the structure and properties of porous ceramic skeleton infiltrated with liquid aluminum alloy. Design/methodology/approach: The composite was manufactured by the use of porous material pressure infiltration method. Hardness test was carried out with Rockwell method in A scale. The wear resistance was measured by the use of TSM Instruments Tribometer. The tribomiter allows to realize dry friction wear mechanism conditions. Additionally the examinations on stereomicroscope of wear tracks were made. Findings: Composite materials reinforced by porous skeleton manufactured on the base Al2O3 particles show superior in mechanical properties and wear resistance than the aluminum alloy EN AC-AlSi12 constituting the matrix. The developed composite materials also have better wear resistance compared to the matrix. Practical implications: Tested composite materials can be applied in many industry branches, among others, in the automotive, aerospace industry and in manufacturing of professional sports equipment. Originality/value:The investigation results shows that the worked out technology of composite materials manufacturing can find the practical application in the production of near net shape and locally reinforced elements.

3

Dry sliding wear characteristics of 0.13 wt. % carbon steel

Gupta V.K., Ray S., Pandey O.P.

Materials Science Poland

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2008

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Vol. 26, No. 3

617--631

EN

Wear characteristics of 0.13 wt. % plain carbon steel, heat treated under various conditions, were monitored on a standard pin-on-disk wear testing machine under the normal loads of 2.5, 4.5 and 5.5 kg and at a constant sliding velocity of 1 m/s. Weight loss of the specimen was measured at various time intervals to obtain wear rate. The variation in volume loss with sliding distance indicated the presence of run-in wear followed by steady state wear. The wear mechanism was found to be primarily oxidative in nature, which was confirmed by the analysis of worn surfaces and wear debris generated during sliding. Wear resistance was found to be dependent on the microstructure and morphology of the phases. The wear coefficients calculated for various heat-treated specimens revealed that the ferrite-coarse pearlite, ferrite-fine pearlite, ferrite-tempered martensite and ferrite martensite structures show the wear resistance in decreasing order.