I. O. Vakulenko

• Bachelor of Applied Science
• Dnipropetrovsk National University of Railway Transport

During a study of the combustion process of a direct polarity electric arc, a directly proportional dependence of the electric current value on the degree of cold plastic deformation of carbon steel used as an electrode was found. To calculate the value of the electric current during arc burning, in the indicated ratio, it was proposed to replace t...

In comparison with low carbon steels, there is increased interest in the use of aluminium-based alloys as materials for the manufacture of welded structures rolling stock of railway transport. During friction stir welding aluminium-based alloy, against the background of the analysis structural transformations, issues of development hardening proces...

From an analysis of the dependence complex of carbon steel properties on structural parameters, it was found that for an isostructural state, the influence of austenite grain size on impact strength exceeds the dependence on carbon content. As a result of explaining correlation relationships between individual mechanical characteristics, to evaluat...

Purpose. The main purpose of the work is to determine the peculiarities of the development of recrystallization processes of carbon steel austenite depending on the degree of hot plastic deformation and to develop proposals for improving the structural state of the metal of the railway solid-rolled wheel. Methodology. Two carbon steels of a railway...

The metallographic and fractographic analysis methods were used to study the influence of the cast metal quality on the causes of the destruction of a railway carriage under high dynamic and cyclic loads. As a result of study structure fracture surface of the side frame freight car truck, the detected elements indicate simultaneous presence of fati...

The systematization results of microstructure studies of carbon steel has made it possible to explain the mechanism of formation of certain damages to the rolling surface of railway wheels during operation. The evaluation ability of metal to strain hardening was used to explain the nature of the influence compactly located non-deformable dispersed...

On a fragment of the rim of a railway wheel removed from service, the volume of the metal with non-metallic inclusions located near the tread surface was investigated. The use of the microhardness measurement technique made it possible to establish the nature of strain hardening of carbon steel near non-metallic inclusions. It showed that with a no...

Purpose. The work is aimed to clarify the softening mechanism during the heating of martensite hardened carbon steel, which is of practical importance, especially in the development of the production technology of rolled products with different levels of hardening. Methodology. The samples after martensite hardening were tempered at the temperature...

The processing by pulses of electric current (PEC) of a fragment of the rim of a railway wheel was carried out on the DS10D equipment. When the density of the electric current is from 3 to 17 A/mm ² , the processing cycle consisted of the action of a pulse with a duration of 2.5-3 s and a pause between pulses of 4 s. After 150 cycles of PEC, the ha...

The aim of this work is to study the basic principles of thermal cyclic processing (TCТ) of metals to obtain structures that determine the optimal complex of mechanical properties. The basic provisions of metal heating centers using periodically repeated heating and cooling cycles are given. The TCТ method, as a heat treatment method, is based on c...

The procedure of treatment of thermally hardened steel by pulses of shock waves from electric discharges in water increases its hardness and the limited fatigue strength. As a result of the action of shockwave pulses, the number of dislocations increases. This guarantees the propagation of deformation in a cycle, which promotes the increase in cycl...

Journal homepage: http://sjsutst.polsl.pl Article citation information: Vakulenko, I., Grischenko, N., Vakulenko, L., Efremenko, V., Proiydak, S., Perkov, O. Structure and properties of the steel railway wheel disc after forced cooling. Summary. The technological use of accelerated cooling makes it possible to improve the carbon steel properties of...

The effect of plasma parameters on the case hardening of wear-resistant high-chromium cast iron in different structural condition is studied. Correlation relations were established between the initial and finite microstructure of the surface layer formed after plasma hardening at different heating rates. Microhardness profiles over the cross-sectio...

Purpose. The article is aimed to evaluate the influence of structural parameters of low-carbon steel on arcing process. Methodology. The values of the micro- and substructure characteristics of the electrode wire metal were changed by varying the parameters of heat treatment and cold deformation by drawing. The degree of plastic deformation was obt...

Purpose. The article is aimed to investigate the structure of the composite coating obtained by pulse-plasma treatment using cathodes of high-carbon material with higher amount of carbide-forming elements. Methodology. The coating was produced using electrothermal axial plasma accelerator with the following operating parameters: voltage applied...

It is shown that the intense cooling (with rates of 2–9°C/sec) of wheel rims after their hot rolling in a rolling mill increases the yield limit and the ultimate strength of the metal. It is also established that, in the absence of supersaturation of the solid solution with carbon atoms in the course of this kind of cooling, the mechanical properti...

Purpose. The paper aims at estimation of resource of strength increase for railway wheel disk. Methodology. The material for research was carbon steel of railway wheel containing 0.57%C, 0.65%Si, 0.45%Mn, 0.0029%S, 0,014%P, 0,11%Cr. A railway wheel was heated to the temperatures above and was held at this temperature until the completion of аusteni...

Causes of reasons and explanation of mechanism forming damages of railway wheels tread were investigated. At slipping on contact surfaces wheelrail a between by simultaneous development of processes of work-hardening and softening metal determines the terms of origin damages of railway wheels tread were fixed.

Effect of pulses of electrical discharge in the water at the magnitude of the limited endurance under cyclic loading thermally hardened carbon steel was investigated. Observed increase stamina during cyclic loading a corresponding increase in the number of accumulated dislocations on the fracture surface. Using the equation of CofinoManson has reve...

Purpose: The work is directed at elaboration of softening effect of carbon steel of a railway wheel after the speed-up cooling to the different temperatures. Methodology: Material for the research was carbon steel of a disk railway wheel with content of 0.57 % C, 0.65 % Si, 0.45 % Mn, 0.0029 % S, 0.014 % P, 0.11 % Cr. Specimens as plates 3 mm thick...

Purpose. The research supposes the explanation of influence of stress impulses from an electrical discharge in water on the level of the limited endurance at a cyclic loading of the thermally work-hardened carbon steel. Methodology. Material for research was steel 45 (0,45 % carbon) with сoncentration of chemical elements within the limits of steel...

Purpose. It is determining the nature of the ferrite grain size influence of low-carbon alloy steel on the speed propagation of acoustic vibrations. Methodology. The material for the research served a steel sheet of thickness 1.4 mm. Steel type H18T1 had a content of chemical elements within grade composition: 0, 12 % C, 17, 5 % Cr, 1 % Mn, 1, 1 %...

Purpose. The purpose of work is a comparative analysis of chemical compounds influence on the process of forming arc welding and condition of its burning. Methodology. A wire with diameter 3 mm of low carbon steel with contain of carbon 0.15% was material for electrode. As chemical compounds, which determine the terms of arc welding forming the fol...

Purpose. Assessing the impact of technological parameters on the properties of the complex in the manufacture of valves with a high level of safety. Methodology. Material for the study was selected alloy steel 20ХГС2. Curing rods with a diameter of 6,5 mm was performed rapid cooling from temperatures of 1080…1100 °C. The heating was carried out in...

Purpose. Damageability estimation of carbon steel in the conditions of cyclic loading. Methodology. The steel fragments of railway wheel rim and rail head served as material for research with chemical composition 0.65 % С, 0.67 % Mn, 0.3 % Si, 0.027 % P, 0.028 % S и 0.7 % C, 0.82 % Mn, 0.56 % Si, 0.025 % P, 0.029 % S accordingly. The microstructure...

Purpose. The purpose of work is a comparative analysis of chemical compounds influence on the process of electric arc forming and condition of its burning. Methodology. Material for an electrode was a wire 3 mm in diameter of low carbon steel with contain of carbon 0.15%. As chemical compounds, which determine the terms of forming of arc welding we...

Purpose. The purpose of work is an estimation of influence of an electric spark treatment on the state of mouldable superficial coverage of carbon steel. Methodology. The steel of fragment of railway wheel rim served as material for research with chemical composition 0.65% С, 0.67% Mn, 0.3% Si, 0.027% P, 0.028% S. Structural researches were conduct...

Purpose. Explanation of the influence mechanism of ferrite grain size on the fatigue strength of low-carbon steel. Methodology. Material for research is the low-carbon steel with 0.1% of carbon contnent. The different size of ferrite grain was obtained due to varying the degree of cold plastic deformation and temperature of annealing. The estimatio...

Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of ark welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness w...

Purpose. Modern ideas about the contact interaction of bodies in friction are based on models that take into account the geometric parameters of the surface layers constituting tribosystems. These models provide a high level of adequacy to describe the features of the relief of the surfaces of parts and their impact on the performance characteristi...

Purpose. The purpose of work is the possibility estimation of аthermic technologies use of cold-deformed metal softening for elements of railway car body and wheel. Methodology. The material for research is the carbon steel of the wheel rim fragment containing 0.55%С, 0.74%Mn, 0.33%Si, and the steel 20. The wheel steel is studied after heat strengt...

Purpose. The purpose of the paper is an estimation of degree of metal hardness change for the railway wheel with martensite structure during rolling. Methodology. As strength characteristic the Rockwell hardness is used. Wear tests were conducted in the conditions of normal loading with (10%) and without sliding on the test equipment SMTs-2. Parame...

Introduction. Load increase on the wheel pair ax requires the use of railway wheels with the advanced complex of properties. Except strength properties, the properties of metal resistance to defect nucleation on the wheel thread are of high importance. The above mentioned properties increase is possible by using different technological decisions: a...

The observed questions of estimate degree decrease density dislocations in carbon steel rail wheel after electrical impulse treatment.

The structural changes in the near-surface layers of a railway wheel rim are studied during operation in rolling stock. The standard operating conditions of rail transport are shown to be characterized by alternating impact loading; regular braking; and, hence, periods of rapid heating of the surface layers in wheels that are replaced by intense he...

The effect of the morphology and size of iron carbide in a high-carbon steel on the fatigue strength and critical crack opening is considered. The increase in the fatigue strength induced by a decrease in the pearlite size in medium-and high-carbon steels is caused by the fact that the time of formation of nonuniformities in a uniform dislocation d...

The effect of the ferrite grain size on the fatigue strength of a low-carbon steel is studied. It has been shown that, as the ferrite grain size increases, the fatigue strength decreases due to plastic-flow localization. One of the explanations of this phenomenon is the beginning of the formation of periodical cellular dislocation structures.

Deformation-band nucleation is analyzed to explain the causes that hinder the development of deformation bands in thermally hardened carbon steels.

The effects of the volume fraction of a hardened layer and the amount of a magnetic phase on the ultimate tensile strength of thermally hardened low-carbon rolled bars are considered. A relationship based on the additive contributions of metal volumes having different structural states to the nominal strength has been obtained.

When a low-carbon 12GS2 steel with a martensitic structure is tempered, its softening, which is more intense as compared to the isothermal austenite transformation, is caused by rapid carbon precipitation from the solid solution and a decrease in the dislocation density and in the level of internal stresses. The explanation of the character of chan...

The variation of the flow stress in the region of microyielding and the conditions of formation of a Lüders band are studied for carbon steels. The effects of the ferrite grain size in a low-carbon steel and of the distance between carbide particles in medium- and high-carbon steels on the nucleation of mobile dislocations and on the formation of a...

Dislocation annihilation observed as a result of bend-tensile loading of a cold-rolled low-carbon steel is attributed to the small-angle rotation of individual microdomains. This process is found to involve the shift of existing subgrain boundaries and the formation of new ones.

Carbon steel with volume fraction of cementite from 0.034 to 0.11 is subjected to quenching and tempering, deformation drawing and annealing at 680°C. The values of parameters of strain hardening and properties of steels with improved structure are determined via tension tests with the strain rate equal to 1 · 10-3 s-1. It is found that the rise of...

The critical crack opening displacement in carbon steels subjected to toughening is shown to be related not only to the size of a structural element but also to the parameters of strain hardening and the plasticflow activation energy.

An assessment of effect of ferrite grain size of low carbon steel (0,06% C) and strain hardening parameters on density of mobile dislocations when forming a nucleus of strain band is a purpose of work. The parameters of strain hardening in the field of microyield are estimated via extrapolation of area of parabolic changing in stress. The relations...

The effect of the annealing temperature on the flow stress in the field of microdeformation was studied on quenched carbon steels tempered at 650°C and cold-worked to 30-80%. A partial retention of polygonization boundaries and the formation of new high-angle boundaries that can absorb carbon atoms decrease the transparency of ferrite grain boundar...

Carbon steels, containing 0.23; 0.6 and 0.8% carbon, are subjected to quenching, tempering at 650°C and cold plastic deformation via drawing up to 30, 60 and 80% followed by annealing at 400-680°C for 1 h. Changing in yield stress of microyield field is studied for the wire specimens depending on annealing temperature. X-ray analysis showed a parti...

Using the analysis of an acoustic emission diagram recorded in the course of carbon steel deformation, the points for the beginning of plastic metal yield and for the transition to the homogeneous deformation-induced strengthening region were determined. By analyzing the nucleation and growth of Chernov-Luders bands, it was established, that the in...

The article presents the results of a study of the process of deformation of specimens of carbon steel (with superfine ferrite grain) in tension on the yield plateau as a function of the structure.

Low carbon steel (0.06% C) wires after heat treatment at 450°C, cold drawing with section reduction ε=75% and tempering at 100 - 650°C, 1 hour were tension tested at 20°C at a strain rate 103 s-1. X - ray analysis showed that with the increase of the tempering temperature ttemp the density of crystal defects and dislocation decreases. The strain ha...

Results from the study of the deformation process of specimens from carbon steel (with superfine ferrite grains) under tension on a yield site depending on structure are presented.

Effect of bending-tension deformation parameters on cold rolled low carbon sheet steels has been investigated. Change of a deformation sign or a loading kind during plastic flow is accompanied by decreasing of resistance of small plastic deformation as well as a fall in ultimate strength. Decrease in yield stress level under bending-tension deforma...

The simultaneous occurrence of the ferrite collective recrystallization and the cementite particle coalescence causes the deviation of the carbon distribution on the rod diameter from a normal law under annealing of the cold-drawn low-carbon steel. The cyclic processes of the particle solution and coagulation induce the replacement of the ferrite g...

The properties of carbon steel with a ferrite + cementite + martensite structure were investigated. From the results of metallographic investigations it follows that the collective recrystallization of ferrite cannot be slowed in low-carbon steel, even when a volume percentage of the austenitic phase is added to the cementite. The effect of defects...

Plastic flow propagation in the Chernov-Luder deformation zone in steels with super-fine ferrite grains is accompanied by drops in flow stress. Refinement of ferrite grain size increases the mobile dislocation density required for plastic flow and decreases its activation energy, which promotes development of unstable metal flow. For the investigat...

It is possible to improve the tensile properties of metal with a certain combination of deformation temperature and rate parameters by using the strengthening influence of static and dynamic strain aging processes. The authors describe investigations on carbon steel wire with 0. 78%C subjected to 77% cold work. Warm straightening enables relative e...

The aim of this present paper was to estimate the ferrite structure stability on recrystallization as a function of the volumetric proportion and the dispersity of the uniformly globular cementite particles. The investigations were carried out on nonalloyed carbon steels of 0. 06-0. 8% carbon content. The initial structure was based on hardening an...

1. For high-carbon steels with uniformly distributed globular cementite the dependence or the strain-hardening coefficient on ferrite grain size is similar to that observed for single-phase metal. 2. An increase in cementite particle volume fraction with the same ferrite grain size leads to an increase in the value of m. 3. The effect of ferrite gr...

The variation in strength properties of low-carbon nonalloy steels with a ferrite-martensite structure is described by a relation of Hall-Petch type, in which the structural parameter is the distance between martensite regions ( lambda ). It has been experimentally established that the dependence of the strengthening of steel with a ferrite-martens...

After interrupted quenching or interrupted quenching with subsequent induction heating, the surface layer, to a minimum depth of 0. 3 mm, in 20GSR and 35GS reinforcing steels consisted of a virtually homogeneous microstructure (ferrite matrix and globular carbides) with a maximum hardness of 280 HV. After interrupted quenching, tensile residual str...