Showing papers in "Journal of Friction and Wear in 2013"
TL;DR: The Mechanism of Wear Process of Cobalt-Carbide was studied in this article, where it was shown that the machining of chromium-based alloy with a more heat-resistant process of the wear of the carbide inserts with or without a nanoscale coating occurs less intensively than for the tool wear process of Ni alloy.
Abstract: The work “The Mechanism of Wear Process of Cobalt-Carbide” shows the result of studying cemented carbide when machining refractory alloys based on chromium (X65HBΦT) and nickel (XH77TУP). The conducted research has shown that the machining of chromium-based alloy with a more heat-resistant process of the wear of the carbide inserts with or without a nanoscale coating occurs less intensively than for the tool wear process in the machining of Ni alloy It is established that this effect is connected with different crystal structures, phase contents, and properties of the heat-resistant alloys in question.
38 citations
TL;DR: In this paper, the surfaces of carbide tools made of VK8 and H13A alloys covered with an NbHfTi alloy layer deposited by magnetron sputtering is modified by electron beam treatment.
Abstract: The surfaces of carbide tools made of VK8 and H13A (Sandvik Coromant) alloys covered with an NbHfTi alloy layer deposited by magnetron sputtering is modified by electron beam treatment. This yields an interlayer with concentrations of the alloying elements that gradually vary with its depth. A gradient wearresistant (TiAl)N coating is deposited on this interlayer. Results of studying this composite using X-ray structural analysis are presented. The results of comparative mechanical tests that show the potential of the proposed treatment method are considered.
26 citations
TL;DR: In this paper, the effect of the coatings on cutting forces, coefficient of friction, tool surface tension, and tool vibration due to variable tangential forces is investigated at interrupted cutting.
Abstract: The paper presents the studies of mono- and multicomponent nitride vacuum and plasma coatings (Ti100 − xAlx)N, etc. at interrupted cutting. The contact processes during milling and the effect of the coatings on cutting forces, coefficient of friction, tool surface tension, and tool vibration due to variable tangential forces are considered. The influence of the coatings on abrasive wear resistance and resistance to cracking at variable thermal power loading is proved.
25 citations
TL;DR: In this article, the effect of chemical composition and heat treatment on the microstructure and abrasive wear resistance of V-Mn, V-Ni-Cr, and V-Mo spheroidal vanadium carbide cast irons (18-23 vol %) has been studied.
Abstract: The effect of the chemical composition and heat treatment on the microstructure and abrasive wear resistance of V-Mn, V-Ni-Cr, and V-Mo spheroidal vanadium carbide cast irons (18–23 vol %) has been studied. The wear resistance has been determined under conditions of wear by abrasives with various hardnesses, i.e., corundum and quartz and compared to that of high-chromium cast iron with 13% Cr. It has been found that the advisability of using high-vanadium cast irons is governed by the hardness of the abrasive. When a hard abrasive, i.e., corundum was used, V-Mo cast iron with the maximum concentration of spheroidal VC carbides, which were uniformly distributed in the martensitic matrix, had the highest wear resistance. When a soft abrasive, i.e., quartz, was applied, high-chromium cast iron with a hardness of 68 HRC, which contained the largest amount of M7C3 carbides, was more wear-resistant. In the course of isothermal exposure at 300–1000°C, V-Ni-Cr and V-Mo cast irons with an austenitic structure had high resistance to phase and structural transformations. However, the properties and microstructure of V-Mo cast irons with a martensitic matrix depended strongly on the temperature of exposure during heat treatment.
22 citations
TL;DR: In this paper, features of the wear of cutting tools made from nitride ceramics were determined when machining nickel-based AP741NP alloy, and the performance of these tools proved to depend on the cutting modes, as well as the properties and structure of the materials.
Abstract: The experimental results have demonstrated that tools made from nitride ceramics have high efficiency in the high-speed machining of nickel-based AP741NP alloy. The wear of these tools proved to depend on the cutting modes, as well as the properties and structure of ceramics. Features of the wear of cutting tools from nitride ceramics are determined when machining nickel-based AP741NP alloy.
20 citations
TL;DR: In this paper, the model of experimental tooth wear face milling on the back surface of the processing time has been proposed to calculate the change in of wear in processing for arbitrary cutting conditions.
Abstract: In this paper, the model of experimental tooth wear face mills on the back surface of the processing time. Using regression analysis model, the flank of wear on the processing time takes into account the feed, depth and cutting speed for face milling. The created model can calculate the change in of wear in processing for arbitrary cutting conditions of face milling.
19 citations
TL;DR: In this article, the problem of improving the accuracy of predicting the tribomechanical characteristics of joints made of polymeric composites is addressed, and the application of the two-level method of calculations is shown to determine the contact parameters and volume stress strained state of gears made of disperse reinforced polymeric composite composites.
Abstract: The problem of improving the accuracy of predicting the tribomechanical characteristics of joints made of polymeric composites is addressed. The application of the two-level method of calculations is shown to determine the contact parameters and volume stress strained state of gears made of disperse-reinforced polymeric composites. The obtained dependences can serve the main calculation optimization of concentration of reinforcing filler in order to boost the life of gear based on the criterion of the bending strength of worn teeth.
17 citations
TL;DR: The surface of the WC/Co carbide tool was modified by an electron beam with the magnetron sputtering of Nb + Hf + Ti alloy to obtain a gradient interlayer before hardfacing with (Ti + Al)N as discussed by the authors.
Abstract: The surface of the WC/Co carbide tool was modified by an electron beam with the magnetron sputtering of Nb + Hf + Ti alloy to obtain a gradient interlayer before hardfacing with (Ti + Al)N. The results of investigations of the composite using a scanning electron microscope equipped with a device for X-ray energy dispersion spectroscopy are given. The results of the comparative mechanical tests show reduced wear rate.
17 citations
TL;DR: In this article, the authors evaluated the effect of a nanostructured functionally oriented coating particle formed by the method of cladding by a flexible tool (CFT) and evaluated their impact on the reduction of generated tooth gearing noise.
Abstract: The results of a study on the technological capabilities of the modification of working profile of the teeth of the gears by nanostructured functionally oriented coating particles formed by the method of cladding by a flexible tool (CFT) and evaluated their impact on the reduction of generated tooth gearing noise. It is established that the efficiency of the technology CFT used for the noise reduction of bevel gear drives of machine tools is largely determined by the rational choice of the donor material composition for the formation of a coating. In some cases, gear teeth made from various materials formed on the working profile can significantly change the general character of the distribution of the frequencies of sound energy reducing the level of noise at one frequency and remaining unchanged or even higher at others. The best results in lower noise level of gearing in the whole spectrum of frequencies provided by the bronze-graphite Br05S20Gr0.5DMO0.5 coating. The decrease in noise at the general level was 2–4 dBA depending on rotation speed and, on a separate spectral component, reaches 6–9 dBA.
13 citations
TL;DR: In this article, the authors describe a geometric model of the height of microroughness on the machined flat surface after the face milling with the account of wear of tools.
Abstract: The present paper describes a geometric model of the height of microroughness on the machined flat surface after the face milling with the account of wear of tools. The model takes into account the height variations of microroughness on the flat surface due to the dimensional wear of the radius portion of apexes of face mill teeth. The work resulted in the findings of the height of microroughness at different feeds, rounding radii, different front and back angles of the mill tooth taking into account the wear of tools over the tailing surface.
13 citations
TL;DR: In this article, a method for evaluating the tribological parameters and service life of the piston-cylinder tribosystem of a diesel engine based on calculations and experimental studies is presented, which makes it possible to determine the calculated duration of contact between the friction surfaces of the tribos system; to obtain an experimental dependence of the wear rate on the contact pressure in this friction pair; and, based on this, to evaluate the service life, taking into account the mode of its operation as a component of a machine.
Abstract: A method for evaluating the tribological parameters and service life of the piston-cylinder tribosystem of a diesel engine based on calculations and experimental studies is presented. This approach makes it possible to determine the calculated duration of contact between the friction surfaces of the tribosystem; to obtain an experimental dependence of the wear rate on the contact pressure in this friction pair; and, based on this, to evaluate the service life of the piston-cylinder tribosystem of the diesel engine taking into account the mode of its operation as a component of a machine.
TL;DR: In this article, a new design of a plasmatron with an interelectrode insert and coaxial injection of powder into a plasma jet was proposed for obtaining wear-resistant coatings.
Abstract: A plasma method for obtaining wear-resistant coatings is proposed that enables one to spray powders of different dispersions and composition, as well as to obtain coatings of low porosity and increased hardness. A ceramic or metal powder enters in the jet of thermal plasma where the particles are uniformly heated due to a new design of a plasmatron with an interelectrode insert and coaxial injection of powder into a plasma jet. In this case, a high efficiency of plasma spraying and the control of layer structure and quality are ensured. Thermal and technological studies of the efficiency of the formation of a high-temperature heterogeneous jet and the plasma spraying of coatings of metallic (a fraction of 40–100 μm) and aluminum oxide powders with basic main particle size of 28–40 μm were conducted using an annular input of powder with gas focusing. The nature of flowing Al2O3 particles from the radial-annular slot for powder input with transporting gas is investigated. Statistical distributions of temperature and velocity of the particles on the axis of the plasma jet are presented. The sizes of the area of plasma jet are determined in which particles are melted as much as possible. The results of spraying and study of the coating properties are given.
TL;DR: In this paper, a dimensionless heat problem for a friction pair of a multidisc brake was formulated under conditions of a linear decrease in the friction power of discs with time, and the validity of a mathematical model of the temperature field in the discs of the brake has been experimentally confirmed and functional dependences of the maximum temperature of friction surfaces of the discs on values of the main performance parameters were obtained.
Abstract: A dimensionless heat problem for a friction pair of a multidisc brake was formulated under conditions of a linear decrease in the friction power of discs with time. Thermal state of friction pairs of the multidisc brake under load and velocity conditions of the friction of the discs that simulate service brakings of a wheel tractor was experimentally and theoretically studied. The validity of a mathematical model of the temperature field in the discs of the brake has been experimentally confirmed and functional dependences of the maximum temperature of friction surfaces of the discs on values of the main performance parameters have been obtained.
TL;DR: In this paper, the authors evaluated the increase in the fatigue resistance of dies during the extrusion of steel 45 blanks with applying active friction forces, during which the mold moves in the direction of a blank material flow with a velocity that exceeds the flow velocity, making it possible to unload dies and produce parts from medium-carbon and low-alloy steels.
Abstract: A highly productive method for the cold die forging of blanks makes it possible to fabricate parts with smooth surfaces and the required mechanical characteristics without subsequent heat treatment and machining. The field of application for this method is restricted to high stresses in dies that deform a blank, which reduces their fatigue resistance. Extrusion with applying active friction forces, during which the mold moves in the direction of a blank material flow with a velocity that exceeds the flow velocity, makes it possible to unload dies and produce parts from medium-carbon and low-alloy steels by cold die forging. This work deals with assessing the increase in the fatigue resistance of dies during the extrusion of steel 45 blanks with applying active friction forces.
TL;DR: In this paper, the tribological properties of nanocomposite Ti-Hf, (Ti, Hf)N, and (Ti Hf, Si-N)N coatings deposited by the pulse HF-assisted vacuum arc method are studied.
Abstract: The tribological characteristics of nanocomposite Ti-Hf, Ti-Hf-N, and Ti-Hf-Si-N coatings deposited by the pulse HF-assisted vacuum arc method are studied. A substantial increase in the wear resistance and a decrease in the coefficient of friction of a protective Ti-Hf-Si-N coating compared to the steel substrate and protective Ti-Hf and (Ti, Hf)N coatings are found and explained.
TL;DR: In this article, a numerical and analytical model is constructed to calculate the deformation friction force component when the regular relief die moves over the viscoelastic base, which is modeled with the Kelvin body with the relation time spectrum.
Abstract: The numerical and analytical model is constructed to calculate the deformation friction force component when the regular relief die moves over the viscoelastic base, which is modeled with the Kelvin body with the relation time spectrum. The developed friction model is applicable to both the discrete and full contact between interacting surfaces. The die regular relief is modeled with a set of surface points. The results obtained with the developed model are compared for the case of full contact with the analytic calculation. The sliding velocity and the die regular relief shape are studied to identify the influence on the contact characteristics and the deformation componentof the coefficient of friction.
TL;DR: In this article, the influence of the chemical structure of polyfluorinated alcohols within their nanocomposites with Na+-montmorillonite to change the tribological behavior of filled poly-ɛ-caproamide was considered.
Abstract: The paper considers the influence of the chemical structure of polyfluorinated alcohols within their nanocomposites with Na+-montmorillonite to change the tribological behavior of filled poly-ɛ-caproamide. The introduction of fluoride organoclay in poly-ɛ-caproamide proved to change both the structure of surface layers of the polymer samples and its susceptibility to intense mechanical deformation.
TL;DR: In this paper, the mechanical and tribological properties of thin oxide coatings that are produced by the carboxylate method and have various chemical compositions and thicknesses and are deposited on substrates from different materials (steel or quartz glass) have been assessed.
Abstract: The mechanical and tribological properties of thin (up to 300 nm) oxide coatings that are produced by the carboxylate method and have various chemical compositions and thicknesses and are deposited on substrates from different materials (steel or quartz glass) have been assessed. The study involves the surface examination and the determination of the surface roughness of specimens using optical and atomic force microscopes, the determination of the elastic properties of the coatings based on indentation results, as well as the study of their tribological behavior during dry and lubricated sliding.
TL;DR: The tribological characteristics of sintered tin bronze with additions of oxides of aluminum and nickel have been studied in this paper, where the presence of Motor Life Professional additive in oil reduces coefficient of friction, the temperature in the friction zone, and the volume wear rate of rubbing surfaces.
Abstract: The tribological characteristics of sintered tin bronze with additions of oxides of aluminum and nickel have been studied. The addition of ultrafine particles of alumina or the mixture of alumina and nickel oxide to sintered tin bronze reduces the coefficient of friction, the temperature in the friction zone and the volume wear rate of the rubbing surfaces. The average coefficient of friction of the material does not change substantially over time. During wear, the chipping of oxide microparticles was observed, which led to a change in the roughness of the working surfaces. The presence of Motor Life Professional additive in oil reduces coefficient of friction, the temperature in the friction zone, and the volume wear rate of rubbing surfaces.
TL;DR: In this article, the formation of wear particles under various loading conditions is discussed, and it is shown that at the initial stage, the volume fatigue fracture of friction members that experience dynamic loading results from their fatigue wear.
Abstract: Regularities of the fatigue fracture of surface layers of metals, as well as polymer and inorganic materials, under friction are discussed. The kinetics of the growth of fatigue microcracks and mechanisms of the formation of wear particles under various loading conditions are described. It is shown that, at the initial stage, the volume fatigue fracture of friction members that experience dynamic loading results from their fatigue wear.
TL;DR: In this article, the melting of an ultrathin lubricating film clamped between two atomically smooth solid surfaces that are in relative motion is studied based on the Lorentz model for the approximation of a viscoelastic medium.
Abstract: The melting of an ultrathin lubricating film clamped between two atomically smooth solid surfaces that are in relative motion is studied based on the Lorentz model for the approximation of a viscoelastic medium. An equation of motion for the stresses has been derived in the form of a three-order differential equation and analyzed at various friction surface temperatures. In all cases, the phase portraits and the time dependences of the stresses have been plotted. It has been found that, depending on the temperature and the lubricant parameters, either the damped oscillation mode or the stochastic oscillation mode may occur. The stochastic oscillation mode is presented in the phase plane as a strange attractor. It has been shown that initial conditions have a critical effect on the system behavior. Based on the model, the behavior of two types of tribosystems, i.e., with the unidirectional shear of the surfaces and under an alternating external effect, has been described.
TL;DR: In this article, the tribological properties of the coatings based on fine-grained VK6-M hard alloy, chromium, and molybdenum have been investigated.
Abstract: The tribological properties of the coatings based on fine-grained VK6-M hard alloy, chromium, and molybdenum have been investigated. The coatings were obtained by the electrospark deposition followed by the laser treatment. The electric spark deposition does not affect the coefficient of friction and temperature in the friction zone of the coated surface in contrast to steel 45 surface. Additional laser treatment reduces the dispersion of the friction coefficients and temperatures, but hardly alters their level. The wear rate of the coatings increases in the direction VK6-M → Cr → Mo → steel 45. A hard alloy coating is most effective, since the wear rate decreases as much as 15 times compared to steel 45. The wear rate of the coatings based on chromium and molybdenum is 1.7 and 1.4 times lower than that of steel 45. The laser treatment reduces the wear rate even more, i.e., by 70% for the coating based on the hard alloy and 3.5 and 3 times, respectively, for coatings based on chromium and molybdenum.
TL;DR: In this article, the results of tribotests of nanosized carbon coatings formed on silicon surfaces by the pulse vacuum-arc method at various orientations of substrates with regard to a carbon plasma flow are presented; the tribot tests were carried out for as-deposited coatings and coatings annealed in vacuum at 600 and 800°C.
Abstract: Results of tribotests of nanosized carbon coatings formed on silicon surfaces by the pulse vacuum-arc method at various orientations of substrates with regard to a carbon plasma flow are presented; the tribotests were carried out for as-deposited coatings and coatings annealed in vacuum at 600 and 800°C. It has been shown that, among as-deposited coatings, the carbon coating deposited on a substrate perpendicular to the axis of the plasma flow has the highest wear resistance. An increase in the wear resistance of diamond-like carbon coatings after annealing at 600°C has been found.
TL;DR: In this article, the friction between ultrahigh molecular weight polyethylene and ground steel surfaces is studied, and it is shown that the initial stages of friction that occur on the polished surface are characterized by complex physicochemical transformations that develop up to the formation of Fe-O-C groups.
Abstract: The friction between ultrahigh molecular weight polyethylene and polished and ground steel surfaces is studied. It is shown that the initial stages of friction that occur on the polished surface are characterized by complex physicochemical transformations that develop up to the formation of Fe-O-C groups. As a result this, in the experiment, a hydrophobic modified nanosized steel surface has gradually formed for 20 min; the increment of mass at the surface has been measured at an accuracy of 1 × 10−4 g.
TL;DR: In this article, the problem of measuring static friction at high temperatures and low contact pressures is theo� retically analyzed, as well as the instruments for the accurate determination of the coefficient of static friction for contact pairs made of steel and bronze.
Abstract: The problem of measuring static friction at high temperatures and low contact pressures is theo� retically analyzed, as well as the instruments for the accurate determination of the coefficient of static friction at high temperatures for contact pairs made of steel and bronze The results of experimental investigation show that at low contact pressure and temperature above 120°C coefficient of static friction dramatically increases This increase in the coefficient of friction can be of great practical value with regard to the load capacity of contacts where external forces are balanced with friction forces
TL;DR: In this article, the physical and mechanical properties of multicomponent nitride ((AlSi, Ti)N and (AlSi and Cr)N), carbides ((Al Si, Ti)-C:H and (alSi, Cr)-C :H) coatings deposited on the surface substrate from 40Kh steel was carried out to determine the impact of the load and the sliding velocity on the coefficient of friction.
Abstract: The study of the physical and mechanical properties of multicomponent nitride ((AlSi, Ti)N and (AlSi,Cr)N), carbides ((AlSi, Ti)-C:H and (AlSi,Cr)-C:H) coatings deposited on the surface substrate from 40Kh steel has been carried out to determine the impact of the load and the sliding velocity on the coefficient of friction. The empirical model of the coefficient of friction of the coating-aluminum couples has been proposed in order to find the nature of the friction wear of coatings. A comparative evaluation of the wear resistance of the coatings at normal and elevated temperatures has been conducted.
TL;DR: In this paper, the effect of a phenolformaldehyde binder and the nature of reinforcing fibers on the specific features of the friction of polymer composite materials (PCMs) and the formation of their self-lubricating properties is shown.
Abstract: The effect of a phenolformaldehyde binder and the nature of reinforcing fibers, i.e., polyoxadiazol and carbon fabrics, on the specific features of the friction of polymer composite materials (PCMs) and the formation of their self-lubricating properties is shown. The friction of these PCMs is experimentally studied and an analysis of specific features of this process is carried out based on the first formulated general principle of the structure of a friction surface of these PCMs that implies the rigid fixation of fibers in the structure of a fabric. The effect of properties of the fibers and binder on this process is established.
TL;DR: In this article, a model of dynamic effect during low-amplitude oscillations of surfaces comparable with the preliminary displacement and the first acts of sleep under the oscillating tangential loading of the contact is developed.
Abstract: A model of dynamic effect during low-amplitude oscillations of surfaces comparable with the preliminary displacement and the first acts of sleep under the oscillating tangential loading of the contact is developed. Solving a system of differential force balance equations has yielded the main characteristics of the process of the dynamics of a nominally stationary contact depending on the governing parameters of the system. Regularities of the friction characteristic at low sliding velocity are determined with allowance for the preliminary displacement phenomenon, the Stribeck effect, as well as the parameter of the plasticity and viscosity of friction. The model allows one tracing the evolution of relative displacements and slip velocities, calculating phase diagrams, as well as deriving the friction characteristic and real slip amplitudes typical of the mixed friction mode and low-amplitude fretting.
TL;DR: In this article, the deformation of the surface layer induced by the rolling and sliding of a rigid cylinder is investigated using ideal plastic plane strain theory taking into consideration contact friction, and the plastic region and length of the contact arc related to the forces and the moment applied to the cylinder are calculated.
Abstract: Steady-state plastic deformation of the surface layer induced by the rolling and sliding of a rigid cylinder is investigated using ideal plastic plane strain theory taking into consideration contact friction The plastic region and length of the contact arc related to the forces and the moment applied to the cylinder are calculated Results are studied for rolling friction theory in the case of large contact loads and for surface plastic-layer deformation to increase the wear resistance and fatigue strength of machine parts
TL;DR: In this paper, the main directions and first results of developing friction modifiers for a rail-freight car wheel system are presented and a model for calculating forces of rolling friction with longitudinal and lateral creep is proposed.
Abstract: The main directions and the first results of developing friction modifiers for a rail-freight car wheel system are presented. A model for calculating forces of rolling friction with longitudinal and lateral creep is proposed. The relative slip and the thermal state of the contact zone are assessed. The concept of developing modifiers is presented and results of laboratory tribotests of steel specimens with one of the variants of modifying coatings are presented.