Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya最新文献

{"title":"INVESTIGATION OF STRUCTURE AND SEVERAL PROPERTIES OF CARBON STEEL OF GRADE 50 DEFORMED BY DRAWING","authors":"M. V. Chukin, М. Polyakova, K. Pivovarova, Yu. Yu. Efi¬mova, A. Gulin","doi":"10.17073/0368-0797-2018-7-572-578","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-7-572-578","url":null,"abstract":"The continuous method of deformational nanostructuring is pre­sented. It consists of simultaneous applying of the tensile deformation by drawing, bending deformation while going via the rolls system and twisting deformation to the continuously moving wire. Combination of different kinds of deformation makes it possible to change in a wide range its mechanical properties matching high strength and ductility. The advantage of this scheme of deformational processing consists in arranging together tools which are used in metal ware manufacturing industrial processes as well as its simplicity and compatibility with rates at coarse and middle drawing processes. The scheme of the labo­ratory unit for the method implementation is considered. Wire from medium carbon steel of grade 50 was chosen as the object for inves­tigation because it is considered to be the needed kind of metal ware product. Chemical composition and mechanical properties of this wire are described. Experiments on investigation of the possibility for ultra­fine-grained structure formation effectiveness in carbon steel wire were conducted using the developed laboratory unit. Deformation modes and drawing route are given. Microstructure of the wire from medium carbon steel of grade 50 was studied after different kinds of deforma­tional processing in longitudinal and transversal cross-sections. Dur­ing experimental researches the effect of deformational processing on carbon steel wire microstructure was specified as well as its anisotropy in the cross section. The mechanical properties of the wire of grade 50 steel were studied after different kinds of deformational processing. The verification of these properties was carried out in accordance with the demands in current national wire standards. It was proved that car­bon steel wire mechanical properties matches well with norms set in GOST17305-91. Investigation results of microstructure and mechani­cal properties of the wire from medium carbon steel of grade 50 after different kinds of deformational processing show the perceptiveness of the chosen direction for combination of different kinds of deformation for ultrafine-grained structure formation in carbon steel wire.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73949789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CHALLENGES AND OPPORTUNITIES OF UTILIZATION OF ASH AND SLAG WASTE OF TPP (THERMAL POWER PLANT). PART 1","authors":"G. S. Podgorodetskii, V. Gorbunov, E. А. Agapov, T. V. Erokhov, O. N. Kozlova","doi":"10.17073/0368-0797-2018-6-439-446","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-439-446","url":null,"abstract":" The further development of the Russian coal industry, especially in the regions of Siberia and the Far East, in line with the  Energy Strategy, predetermines the need to address the problem of  utilization of ash and slag wastes in newly implemented projects.  The total amount of ash and slag in the ash dumps in Russia is more  than 1.5  billion tons, and the area occupied by fly ash and slag wastes  (FASW) is more than 220 km2. At the same time, the degree of FASW  use does not exceed 10  %. It is shown that the main solutions for the  recycling of the industrial solid waste generated by thermal power  plants are their use in the production of building materials, road construction, or the complex processing of FASW with the extraction  of metals and the production of building mate rials either. Some fly  ash can be used in agriculture. The physicochemical properties of  fly ash and slag wastes and, accordingly, the directions of their use,  as well as the choice of technology, are determined by the mineral  part of the fossil coals and the way they are burned. To use fly ash in  the construction industry, it is necessary to transfer the ash removal  system to the dry method, accompanied, on the one hand, by a large  volume of capital investments in equipment and facilities for storage,  classification, crushing and grinding, the transfer of new physical and  chemical properties to fly ash and slag waste, and on the other side,  an increase in organizational and transport barriers. Examples of proposed technologies for utilization of ash and slag wastes in the form of metal recovery and production of building materials are given. To  obtain iron-containing concentrates, one-stage magnetic separation  is used, but the quality of the concentrate does not meet modern requirements. The most technologically effective for the extraction of  metals from ash and slag wastes are technologies based on flotation  methods. At the same time, it follows from the provided data that  their application can be limited to economic, organizational factors  and the emergence of new environmental risks. The conclusion is  made on the possibility of using the above technologies for existing  coal-fired power plants only with state support.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79681927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THERMODYNAMICS OF OXYGEN SOLUTIONS IN ALUMINUM-CONTAINING Ni – Cr MELTS","authors":"V. Dashevskii, A. Alexandrov","doi":"10.17073/0368-0797-2018-6-490-493","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-490-493","url":null,"abstract":"Thermodynamic analysis of the effect of aluminum on the solubility of oxygen in Ni – Cr melts has been carried out. Aluminum at  very low levels practically does not affect the concentration of oxygen  in the melt, which is determined by the chromium content. When the  aluminum content is above ~0.01  % for all alloys, it already determines the solubility of oxygen in the melt. The minimum values of  the oxygen concentration are achieved with an aluminum content of  ~0.2  %. With the increase of chromium content in the melt, the minimum oxygen concentration increases. For Ni – 10 % Cr, Ni – 20 %  Cr and Ni – 30 % Cr alloys, it is 2·10–3, 7·10–3 and 10–2, respectively.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78360564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THERMODYNAMICS OF THE PROCESSES OF INTERACTION OF LIQUID METAL COMPONENTS IN Fe – Mg – Al – La – O SYSTEM","authors":"G. G. Mikhailov, L. Makrovets, L. Smirnov","doi":"10.17073/0368-0797-2018-6-460-465","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-460-465","url":null,"abstract":"At the present time, rare-earth elements in metallurgy are used in  the form of mischmetal – a rare-earth elements natural mixture (with  atomic numbers from 57 to 71). It contains about 50  wt.  % of cerium.  The remaining elements are mainly lanthanum and niobium. The specific composition is determined by the ore deposit. Inconstant composition of the modifier containing rare-earth metals (REM) can significantly reduce its efficiency. Experimentally, for every branded steels  composition the ratio of various REMs can’t be selected because of the  high costs of obtaining technically pure rare-earth metals. The task of  determining the each rare earth element optimum concentrations and  complex ligature composition can be solved by thermodynamic modeling. In the framework of thermodynamic modeling, the interaction  between magnesium, aluminum and lanthanum with oxygen in liquid  iron is presented. And the thermodynamic model of steel deoxidation  by these active metals composition is considered. On the basis of available literature data on the phase diagrams of the systems MgO – Al2O3 ,  MgO – La2O3 and La2O3 – Al2O3 , the coordinates of the invariant equilibria points in the system MgO – La2O3 – Al2O3 were determined. The  phase diagram of the system MgO – La2O3 – Al2O3 was constructed. It  made possible to establish all phase equilibria realized in the process  of deoxidation of steel with magnesium, lanthanum and aluminum and  to describe these phase equilibria by chemical reactions equations. The  activity of the components in liquid oxide melts was determined using  the theory of subregular ionic solutions, which takes into account the  dependence of the coordination number of cations on the composition  of the oxide melt. The activity of components in metal melts conjugated with oxide systems were determined by Wagner’s theory using the  parameters of the first order interaction. Equilibrium constants values  for the steel deoxidation reactions are installed indirectly by thermodynamic calculations. On the basis of the obtained data the components  solubility surface in the metal melts of Fe – Mg – Al – La – O system  was constructed, which allowed to determine the liquid metal composition regions associated with the corresponding oxide phase.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80738713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ASSESSMENT OF THE EFFICIENCY OF USING BLIND FEEDERS OF VARIOUS GEOMETRY BASED ON MATHEMATICAL SIMULATION RESULTS","authors":"A. Fedosov, G. Chumachenko, M. А. Khodarev, V. V. Golomeev","doi":"10.17073/0368-0797-2018-7-543-550","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-7-543-550","url":null,"abstract":"A short analysis of existing methods for reducing the feeders’ volume is carried out. Their advantages and disadvantages are singled out. The area of application of optimization methods of the feeders’ form is substantiated with the purpose of increasing the casting yield. The actual location of shrinkage defects in variously designed feeders is considered. The patterns of location and shape of shrinkage cavity are shown depending on the shape of the feeder upper section. This allowed to distinguish four groups of feeders and noted the differences in the effectiveness of their work. To clarify the mechanism of shrinkage defects formation in feeders with a different form of the upper section and to estimate the effectiveness of their work, it is proposed to use methods of mathematical modeling. The appropriateness of using mathematical modeling methods is emphasized, by means of the pos­sibility of idealizing external influencing factors on thermal processes in the form that is difficult to achieve in real conditions of foundry pro­duction. The SOLIDCast application is used as the modeling means. The initial and boundary conditions for mathematical modeling were identical for all types of feeders. The results of the shrinkage cavities prediction are presented as isosurfaces diagrams, the sizes were used for estimation of the feeders work efficiency. The method of estima­tion of variously designed feeders’ effectiveness is proposed on the basis of mathematical modeling results. Characteristics of shrinkage defects location in feeders’ volume are proposed to use for estima­tion of feeder’s effectiveness. Its calculation for the feeders of equal size but having differently designed top part is shown. The introduced efficiency index has a good adjustment with geometric module (ratio between volume and surface of feeder). Increasing feeder’s geometric module increases its thermal efficiency. It is shown that the use of a notch allows to increase feeder’s efficiency. The explanation of mecha­nism of notch thermal behavior and its influence on shrinkage defects location is offered on the basis of analysis of isothermal lines in feed­ers’ cross section. Recommendations towards maximization of casting yield are substantiated due to the change in feeder top part design. The opportunity of increasing of casting yield up to 4% and reducing casting defects by optimization feeder’s upper section shape is shown.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75949394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"СОВЕРШЕНСТВОВАНИЕ ВИБРАЦИОННЫХ ПИТАТЕЛЕЙ-ГРОХОТОВ ДЛЯ ГОРНО-МЕТАЛЛУРГИЧЕСКОЙ ПРОМЫШЛЕННОСТИ","authors":"Василий Иванович Ляшенко, В. З. Дятчин, Всеволод Петрович Франчук","doi":"10.17073/0368-0797-2018-6-470-477","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-470-477","url":null,"abstract":"The main scientific and practical results of the improvement of  vibrating feeders-screens for mining and metallurgical industry are  presented on the basis of dynamic calculation of the vibrating feederscreen with two differently directed self-balancing vibrators. Methods  of theoretical generalizations are described using mathematical statistics, physical and mathematical modeling, computation and feasibility studies, laboratory and full-scale experimental studies, industrial  tests in the conditions of operating enterprises using standard and new  methods. Mathematical modeling and calculation of the parameters of  a vibrating feeder of the PVG type are proposed. It is recommended  when choosing dynamic parameters of the feeder, to use the vibration  transmission coefficient, which is taken within the limits (1.5  –  3.5)g,   and in heavy loading modes, is up to 5g. It is shown that during preparation of breeze coke in the crushing body, from 10 to 50  % of fine  material is received from its bunker with a particle size of 0  –  3  mm,  which is additionally re-milled, reducing the quality of coke. A vibrating feeder-screen with a spatial oscillation of the working element will  increase the efficiency of screening of the material by 15  –  20  % and  will improve the self-cleaning of the screen. The driving forces of the  exciters are directed at different angles of 15 and 45° to the screening surfaceand are attached from each other at a distance equal to half  width of the box, i.e. 600  mm. It is established that in the resonance  mode at a constant amplitude with increasing frequency the coefficient  of the vibro-displacement regime increases according to a quadratic  dependence, at a working frequency of 100 rad/s it also increases from  the loading edge of the feeder to the unloading and from one side to  another, the value of which varies within 2.62  –  2.84.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85832860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OXYGEN SOLUBILITY IN VANADIUM-CONTAINING Fe – Co – Cr MELTS","authors":"A. Aleksandrov, V. Dashevskii","doi":"10.17073/0368-0797-2018-7-579-583","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-7-579-583","url":null,"abstract":"Thermodynamic analysis of the effect of vanadium on the solu­bility of oxygen in Fe – Co – Cr melts has been carried out. Vanadium in Fe – Co – Cr melts at low contents increases oxygen concentration, which is determined by the chromium content. With a higher content of vanadium after changing the mechanism of the interaction process of chromium and vanadium with oxygen, when vanadium already de­termines the solubility of oxygen in the melt, the oxygen concentration initially decreases, and then, after passing through the minimum point, increases.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80278885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FRACTURE RESISTANCE OF “TRANSITION” AREA IN THREE-LAYER STEEL/VANADIUM ALLOY/STEEL COMPOSITE AFTER THERMOMECHANICAL TREATMENT","authors":"T. A. Nechaikina, S. Nikulin, S. Rogachev, V. Turilina, A. Baranova","doi":"10.17073/0368-0797-2018-6-447-453","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-447-453","url":null,"abstract":"The creation of new structural materials for cladding tubes  of fast neutron reactors is an urgent task of modern nuclear power  engineering. A three-layer radiation-resistant and corrosion-resistant material based on vanadium alloy and stainless steel, intended  for work under extreme conditions (high temperatures, radiation  and aggressive environment) of operation of fast neutron reactor  cladding tubes has been developed in recent years. The most important aspect determining the operability of this material during  operation is the quality of the joining of different materials layers  among themselves, determined by the modes of thermomechanical treatment. The effect of the annealing on the chemical composition, structure, and fracture resistance of the “steel/vanadium  alloy” interface in the steel/vanadium alloy/steel three-layer tube,  obtained by hot co-extrusion of three-layer tube billet at 1100  °C  was studied. The 20Kh13 (AISI 420 type) steel for the outer layers and V – 4Ti – 4Cr vanadium alloy for the core were used as the  components of the tube. The structure and chemical composition  in the layer joining zone were studied using the optical microscopy and electron microscopy with X-ray microspectral analysis.  The fracture resistance of the “steel/vanadium alloy” interface was  evaluated by a compression test of a three-layer ring sample with  notch using an acoustic emission (AE) measurement. It is shown  that after co-extrusion a “transition” area of diffusion interaction  having a variable chemical composition with a width of 10–15 μm  is formed between vanadium alloy and steel, which represents the  continuous series of solid solutions, without precipitation of brittle  phases, providing a strong bonding between vanadium alloy and  steel in the three-layer material. No voids, delaminations or defects were detected at the “steel/vanadium alloy” interface. However, a  crack is formed in the steel layer during the compression tests of  the notched semi-ring three-layer samples after hot co-extrusion.  Annealing favorably influences the formation of the “transition”  area due to the increase in the width of the diffusion interaction  area. No cracks or delaminations at the boundary between steel and  vanadium layers were observed in the three-layer tube samples after annealing, and the three-layer material behaves like a monolith  material during testing.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84849751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MATHEMATICAL MODELING OF OPERATION OF THE PALLET CARS’ GRATE BARS MADE OF STEEL 40Kh24N12SL","authors":"D. Ivanov, A. A. Kozhukhov, V. А. Sklyar","doi":"10.17073/0368-0797-2018-7-536-542","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-7-536-542","url":null,"abstract":"To determine the reasons that decrease life of the grate bars of pellet cars from steel 40Kh24N12SL during the operation, a compara­tive analysis of the results of macro-investigations of the grate bars af­ter operation with the results of modeling the operating conditions for the grate was performed. The modeling of the operating conditions was carried out using the finite element method, which allowed achieving high reliability of the obtained results. For the reliability of the model­ing results, the maximum possible number of boundary modeling con­ditions was obtained, obtained from both macro-examples conducted earlier and from the scientific literature. The application of the finite element method made it possible to determine that a high temperature gradient with local overheating zones is formed along the section of the component. It is shown that the nature of overheating is predictable and is related to the conditions of the coolant supply to the working area during operation of the part. It is established that zones with large values of internal stresses and deformations are locally formed during operation. The regularity of appearance of these zones is shown, which highly dependents on the presence of inhomogeneities in the structure of the part, and is also supposedly related to geometric complexity of the casting. It is also established that in the presence of shrinkage shells, all values of stresses and deformations increase sharply, espe­cially in local maximums. In this case, the distribution of local zones with high stresses and deformations in the presence of shrinkage shells remains practically unchanged. An analysis of the location of zones with high stresses and strains made it possible to explain the existing principle of the destruction of the grate by cracking during operation. It is proved that one of the main causes of buckling, cracking and fracture of the grates of the pellet cars made of steel 40Kh24N12SL is the pres­ence of shrinkage shells in the metal structure. As a result of modeling the operating conditions, mechanism of the occurrence of buckling, cracking and fracture of the grates of steel 40Kh24N12SL during op­eration is described, which completely coincides with the results of macro-investigations and observations obtained during operation.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86050223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ПЕРЕРАСПРЕДЕЛЕНИЕ АТОМОВ УГЛЕРОДА В ДИФФЕРЕНЦИРОВАННО ЗАКАЛЕННЫХ РЕЛЬСАХ ПРИ ДЛИТЕЛЬНОЙ ЭКСПЛУАТАЦИИ","authors":"Виктор Евгеньевич Громов, А. А. Юрьев, Ю.Ф. Иванов, В. А. Гришунин, С.В. Коновалов","doi":"10.17073/0368-0797-2018-6-454-459","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-6-454-459","url":null,"abstract":"Using  transmission  electron  microscopy  methods  at  various  distances from the rolling surface along the central axis, changes in  structure, phase composition, and defective substructure of the head  of differentially hardened rails were studied after passed tonnage of  691.8  million tons of gross weight. It is confirmed that prolonged  operation of rails is accompanied by two simultaneous processes of  transformation of structure and phase composition of plate-pearlite  colonies: cutting of cementite plates and dissolution of cementite  plates. The first process is carried out by mechanism of cutting carbide  particles and removing their fragments, accompanied only by change  in their linear dimensions and morphology. The second process of  dest ruction of the cementite plates of perlite colonies is carried out by  leaving carbon atoms from crystalline lattice of cementite on dislocation, as a result of which phase transformation of rails metal is possible. This is due to a noticeable relaxation of mean energy of carbon  atom  s binding to dislocations (0.6  eV) and to iron atoms in cementite  lattice (0.4  eV). The stages of transformation of cementite plates are  considered: enveloping the plates with sliding dislocations and then  splitting them into weakly oriented fragments; penetration of sliding  dislocations from ferrite lattice into lattice of cementite; dissolution of  cementite and formation of nanoscale particles. The presence of nanosized cementite particles in ferrite matrix is noted due to their removal  during dislocation slide. Using expressions of modern physical materials science and X-ray diffraction analysis, influence of content of  carbon atoms on structural elements of rail steel was estimated. It is  shown that prolonged operation of rails is accompanied by a significant  redistribution of carbon atoms in surface layer. In the initial state, the  main quantity of carbon atoms is concentrated in cementite particles,  and after a long operation of rails, along with cementite particles, carbon is located in defects of crystal structure of steel (dislocation, grain  boundaries and subgrains), and in the surface layer of steel atoms carbon is also found in crystal lattice based on α-iron.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78700225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}