Summary

The article describes the problem of friction unit surface layer parts wear resistance assurance based on control of geometrical and physic mechanical properties to be formed the machining.
① Rybinsk State Academy of Aviation Technology named after P. A. Solovjev, 152934, Rybinsk, Yaroslavl region, St. Pushkin, 53, Phone Office: (4855) 222091, Fax: (4855) 213964, E-mail: .
spmom-09v44n4_p-007.pdf (193.79 Kb)

Summary

Thermal fatigue wear is a kind of degradation, which characterises the metallic element friction surface of some couples, like forging dies, fire guns, heavy-duty mechanical brakes, etc. During the drop forging process, the die surfaces are heated. Because this heating has a variable or almost cyclic character, the thermal stresses and strains effects are similar to that, which characterise the low cycle, fatigue. The paper presents the experimental results concerning specific aspects, which characterise thermal fatigue wear of the steels used in forging dies construction, e.g. equations which emphasise the cyclic durability and cyclic strengthening or softening phenomena of the die steels. These data can be used both in designing and exploitation of the forging dies.
① Petroleum-Gas University of Ploiesti, 39 Bucharest Blvd., 100680 Ploiesti, Romania, ,
② S.C. UPETROM- 1 MAI S.A. Ploiesti, St.1 Decembrie, No.1, Ploiesti, Romania ,
spmom-09v44n4_p-013.pdf (158.63 Kb)

Summary

Lubricants facilitate the effective operation of mechanical equipment, reducing friction and wear, but at the same time, they represent a large and diffuse pollution source both in soil and in water. Eliminating or reducing the formation of pollutants and waste pollution prevention makes an important contribution to environmental protection. Biodegradable lubricants represent the technical and environmental alternative for conventional lubrication. Lubricating greases are considered as colloidal dispersions of a thickener in a lubricating fluid. Their biodegradable properties and their lubricating ability depend on the main components: base oil, thickener, and the additives. The aim of our work is to find the most suitable formulations of ecological lubricating greases having good performances, in order to use them as multifunctional lubricants.
① Affiliated at: SC. ICERP S.A., Blvd. Republicii, No. 291A, Ploiesti, Romania, ;
② Affiliated at: Petroleum-Gas University of Ploiesti, Blvd. Bucharest, No.39, Ploiesti, Romania
spmom-09v44n4_p-021.pdf (165.99 Kb)


Summary
The notion „functional atom” (FA) was created in the Center of Tribology at the Technical University of Sofia, in the field of tribology as interdisciplinary science. The functional atom is formed of 3 components similarly to the basic contact system „body-contact-counterbody”. This notion assigns the central role of contacts in the interaction of bodies in nature, techniques and society.
The idea for the FA is expressed in the fact that its two alternatives “body” and „counterbody” do not interact directly, but through the third body – the contact between them, and the contact networks in the whole functional space of the atom.
Six postulates as basis of the model, theory and application of FA are formulated in the present work. The application of FA is illustrated with concrete examples: the development of the macrostructure of tribology as interdisciplinary science;formulation and using of General law of the contact interaction of bodies in the functional space of tribology – friction, wear, lubrication, contact deformation, contact conductance and capillarity. Other illustrations and applications of the model of FA in triboecology, tribotechnologies, engineering education, etc.
① Tribology Center – Sofia, Bulgaria.
② Interdisciplinary Civic Academy – Sofia, Bulgaria.
spmom-09v44n4_p-029.pdf (443.56 Kb)

Summary

Research results of the modification mechanism of the Armenian minerals with fluorocontained olygomers are given. It is shown that, when treating of mineral fillers with fluoroalcon, a modified product is formed saving the structure of fillers with developed layers of fluoroalcon in which chlorine atoms are located on its periphery. It was established that the developed composites based on heterochained polymers and modified fillers are characterised by higher wear resistance, low friction coefficient, and improved strength properties.
① State Engineering University of Armenia, 105 Teryan Str., 375009 Yerevan, Armenia. Tel.: (374 1) 520 436, E-mail: , ,
spmom-09v44n4_p-041.pdf (193.04 Kb)

Summary

The analytical calculation of the coefficient of heat flow distribution and the average contact temperature of the semi-limited body friction with the tetrahedral counterbody are presented, an example of calculating the friction conditions with high contact stresses and velocities is given.
① National metallurgical academy of Ukraine, Gagarina avenue, 4, 49600, Dnepropetrovsk.
② Dnepropetrovsk State Agrarian University, Voroshilov st., 25, 49600, Dnepropetrovsk,
spmom-09v44n4_p-051.pdf (1.82 Mb)

Summary

The objective of this paper is to present a simplified friction measurement test cell for measuring the friction, developed on the main components of the piston-crank-slider mechanism of an internal combustion engine, including complete piston ring packs, piston skirts, connecting rod bearings and crankshaft main bearings. In detail, the main objective of this study was to measure average friction torque absorbed by an engine in motoring conditions. The proposed cell consists of an AC electric motor driving the piston-crank-slider mechanism of a typical, small, single cylinder, four-stroke engine.
Several experimental runs were performed using this cell and the obtained results were compared with results from a detailed numerical engine friction simulation code, previously developed and published by the author(s) [Livanos et al.] Good agreement was found between simulation and experimental results, indicating that the proposed cell is capable of adequately predicting the dynamic friction behaviour of rotating and oscillating engine main components.
① Technological Educational Institute of Athens.
spmom-09v44n4_p-061.pdf (21.2 Mb)

Summary

For definition of the distribution of working load on elements of rolling and the maximum effort transferred by a separate ball on a racetrack surface, the statically indefinable system was considered. The elastic-plastic condition of a racetrack surface was defined at the maximum loading of the rotary mechanism. Recommendations on the increase of reliability and working capacity of the mechanism were made.
① Tomsk State University of Architecture and Building, 2 Solyanaya sq., Tomsk, 634003, Russia.
② Krasnoyarsk Institute of Economic and Trade, 105a Sverdlov st., Minusinsk, 662606, Russia.
spmom-09v44n4_p-071.pdf (1.21 Mb)

Summary

Laws of the formation of properties eutectic gas-plasma coating on an iron-base containing interstitial phases depending on a degree of nonequilibrium conditions are established. It is shown that, after high-temperature diffusion annealing, eutectic coatings work on deterioration in a pair with the couched steel better than up to annealing. A conclusion is drawn on self-organising structure and properties of the investigated coatings during friction and wear processes.
spmom-09v44n4_p-081.pdf (3.90 Mb)