The paper presents the results of development and research of a new resource-saving technology for processing poor oxide and carbonate manganese ores in a unit of jet-emulsion type. The basic principles of creating a jet unit and the technology of processing pulverized manganese ores are considered. For the preliminary reduction of manganese from higher oxides or carbonates decomposition, as well as the removal of moisture from the ore, it is proposed to use a reducing gas, which is a product of the implementation of manganese reduction technology in jet-emulsion unit. Thus, the authors propose to close the process, that is, to create a consistent flow of substance and energy passing through the main jet-emulsion unit and the preparatory unit of the fluidized bed. The main task of calculating the proposed technology is to determine the consumption of crude ore in the fluidized bed unit in order to obtain a given yield of the intermediate product and at the same time to ensure the possibility of complete conversion of high oxides or carbonates of crude ore into lower oxides by reducing gas produced in the main unit. To solve this problem, an optimization task was set and implemented. The first stage is selection of composition and consumption of the reducing gas and determination of consumption of the initial manganese ore, which provides the output of a given amount of the intermediate product. The second stage is solution of the optimization problem for output and composition of the gas, which should ensure the recovery process in the second unit. The paper presents the results of calculating the processing technology in the jet-emulsion unit for oxide ore of the Selezen’skoe and carbonate ore of the Usinskoe deposits. A comparative analysis of two options for processing manganese ores by the proposed technology and by the technology without preliminary recovery and roasting was carried out. The proposed technology of processing manganese ores in a closed-cycle jet-emulsion unit allows one to significantly reduce the specific costs of materials, increase productivity, and significantly reduce the energy intensity of the process compared to the technology of processing poor manganese ores without preliminary reduction or roasting.

The paper considers the features of structural transformations during annealing of the high-entropy alloy Al_0.3CoCrFeNi. The ingots obtained by argon arc melting were subjected to cold rolling with a compression ratio of 50 %. The produced worpieces were annealed in the furnace for 4 hours at temperatures of 200, 400, 600, 800 and 1000 °C. The samples obtained by the described technique were examined using the methods of synchrotron X-ray diffraction in the lumen mode and diffraction of backscattered electrons. The research data indicate that up to a temperature of 600 °C, the structure of the alloys is represented by a single phase with a face-centered cubic lattice. When annealing alloys at temperatures of 800 and 1000 °C, the phase composition is characterized by the presence of two phases: a disordered phase with a face-centered cubic lattice and an ordered phase with a primitive cubic lattice. At temperatures above 800 °C, the burning of alloys is accompanied by development of recrystallization processes. It was found that after annealing at 800 °C, the relative proportion of micro-volumes characterized by inter-angular misorientation of more than 10° was 20 %, and after annealing at 1000 °C – 65 %. Microhardness of the studied samples increases with an increase in temperature up to 600 °C and decreases with a further increase in temperature. Analysis of the width of diffraction maxima using the methods of profile analysis of diffractograms indicates an increase in distortions of the crystal lattice of the ordered phase. This behavior may be associated with the release of nanoscale inclusions in the matrix of the main phase.

For development of new ferroalloys and their application, it is necessary to know their physical and chemical characteristics. The most important characteristics of the alloy, on which assimilation and distribution of the main elements of ferroalloys in the iron-carbon melt depend, are their time of melting and dissolution. Using a mathematical model for calculating the melting time, developed by the employees of the Ural Federal University and the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences, the authors studied the duration of melting of complex nickel-containing ferroalloys in liquid steel. The program allows one to calculate the temperature of a piece of ferroalloy, thickness of the frozen steel crust, size of the alloy piece and duration of the melting periods depending on physicochemical and thermophysical characteristics of the ferroalloys. The melting mechanism of ferroalloys determines the time of their melting in liquid steel. This work contains mathematical modeling of melting of complex nickel ferroalloys containing %: ~10 Ni; 0.5 – 55.0 Cr; ~0.2 C; ~0.2 Si, in iron-carbon melt. It was found that all the alloys under consideration belong to the group of low-melting ferroalloys and process of their melting proceeds in three periods. With an increase in the initial diameter of ferroalloy piece from 3 to 100 mm, the melting time increases by 250 – 300 times. It is shown that an increase in Cr content up to 37 % in complex alloy leads to a decrease in the melting time, and with a further increase in the Cr content to 55 %, an increase in the melting time occurs. A decrease in temperature of liquid steel bath from 1700 to 1520 °С is accompanied by an increase in the duration of melting of complex ferroalloys by 7 – 8 times. In general, the considered complex nickel ferroalloys are characterized by a much faster melting process in liquid steel compared to standard ferrochrome and ferronickel.

In this paper, the processes of decarburization of periclase-carbon and aluminum-periclase-carbon ladle refractories were investigated. Decarburization processes take place already at the stage of drying and heating the lining after repair, during its heat treatment on gas or electric stands. These processes cause irreparable damage to refractories even before the ladle is put into direct operation (before contact with molten steel). One of the ways to increase resistance of carbon-containing refractories against oxidation is the use of antioxidants (Al, SiC, Si, etc.), which are introduced into the composition of the raw mixture at the manufacturing stage. Their action is based on priority oxidation compared to carbon. Antioxidants act in a certain temperature range, which opens up wide opportunities for development of energy- and resource-saving temperature modes for lining heat-treatment. The authors made mogravimetric analysis of periclase-carbon and aluminum-periclase-carbon non-ignited resin-bonded refractories of AMC 78-8/7HG, RI-MC175LC (RI); MayCarb 284-AX (MAYERTON) grades used in the execution of working layers of steel ladle linings. Thermogravimetric analysis of refractory samples was carried out on a LABSYS evo TG DTA DSC 1600 derivatograph when heated to a temperature of 1100 °C at a speed of 15 °C/min. X-ray phase analysis was performed on an XRD-6000 X-ray diffractometer. The results of thermogravimetric analysis are presented in the form of derivatograms. It was established that the maximum rate of carbon oxidation in all cases is reached at a temperature of 700 – 750 °C. Therefore, in order to implement a low-carbonizing first heating of the ladle after repair, temperature modes are recommended for refractories of the studied brands, including low-temperature (up to 500 °C) lining exposure.

The paper summarizes the research on the control of Cantor CoCrFeMnNi high-entropy alloy (HEA) mechanical properties. We studied the effects of alloying with aluminum, vanadium, manganese, titanium, silicon, carbon, and copper on the hardening of HEAs made by vacuum arc melting, laser melting, arc melting, drip casting, mechanical alloying with subsequent plasma sintering, gas sputtering followed by the shock wave and static compaction. It was shown that the addition of 2.5 % TiC and 5 % WC significantly improves the tensile strength, but reduces the elongation to failure. In the 4.4 – 155 µm grain size range, the tensile strength increases as the grain size decreases. The strength and yield limits for any grain size increase as the temperature decreases. Intensive plastic deformation forming nanoscale (~50 nm) grains significantly increases the tensile strength (up to 1,950 MPa) and hardness (up to 520 HV). The strength and ductility can be adjusted with subsequent isochronous and isothermal annealing. The formation of nanostructure phase states with shock compression, mechanical alloying, and subsequent spark plasma sintering significantly increase the tensile strength at room temperature while maintaining excellent plasticity (relative elongation ~28 %). We proposed electron-beam processing (EBP) to control the HEA mechanical properties. We analyzed the deformation curves for the HEA made by wire arc additive manufacturing after EBP at 10 – 30 J/cm² electron beam energy density and made some assumptions about the reasons for the strength and ductility decrease. We also compared the mechanical properties of Cantor alloys made by various processes and found the reasons for the spread of the strength and ductility values.

In this work, the authors studied the elastoplastic properties of the formed tribological layers of WC – (Fe – Mn – C) composites with matrices consisting of γ-iron (containing 4 % Mn (WC – 80G20)) and γ + α′ (containing 20 % Mn (WC – 80G4)) after friction on a high-speed steel disk at contact pressure of 5 MPa and sliding speeds in the range from 10 to 37 m/s. It was established that the main factor determining the morphology of the worn surface is sliding speed. At sliding speeds of 10 and 20 m/s, finely dispersed mechanically mixed tribolayers 3 – 4 µm thick are formed. As the sliding speed increases to 30–37 m/s, the thickness of the tribolayers reaches 10 – 15 µm, and the structure consists of oxidized fragments of WC – (Fe – Mn – C) composites and FeWO₄ complex oxide and does not have a sharp boundary, like the tribolayers formed at lower sliding speeds. The highest values of nanohardness (~33 GPa) and effective Young’s modulus (~523 GPa) were achieved in the WC – 80G4 tribolayer after friction at 10 m/s when the nanoindenter was embedded into agglomerates of fragmented WC grains. This contrasted with the properties of the tribolayers formed at sliding speeds above 20 m/s. The results of nanoindentation showed an obvious effect of tribochemically induced softening in the emerging tribolayer after high-speed sliding at a speed of 37 m/s. Such a layer had a composite microstructure consisting of fragmented composite components cemented in-situ by tribochemically formed FeWO₄ and, in addition to antifriction properties, had an increased indentation fracture resistance.

Over 110 million tons of slag were accumulated in the dumps of the Russian copper-smelting enterprises, and their number is increasing. Environmental taxes and dumps maintenance costs are burdensome, which makes it necessary to make the most complete disposal of these production wastes. At the same time, these slags contain valuable elements, in particular, iron, copper, zinc, selenium, arsenic and some others, the extraction of which can make recycling profitable. The paper presents the results of a thermodynamic calculation of the behavior of copper-smelting slag elements in the mixture with carbon during heating. Modeling was performed using the TERRA software package. The influence of the process temperature in the range of 600 – 1750 °C on reduction of iron, zinc and silicon was analyzed at the amount of carbon in the system corresponding to the stoichiometry of iron reduction reactions and exceeding the stoichiometric one. It was established that when heated above 650 °C, metallic iron appears in the system, and its full reduction is completed at 1250 °C. The appearance of metallic zinc is observed in two temperature ranges: in the first, appearance of zinc is observed with a simultaneous decrease in concentration of zinc oxide; in the second, an increase in concentration of metallic zinc with a simultaneous decrease in concentration of zinc sulfide. At temperatures above 1650 °C, silicon appears in the system. Under laboratory conditions, the processes of solid-phase reduction of iron with the capture of zinc oxide and separation of the reduction products were tested. It was established that as a result of pyrometallurgical separation by melting reduction products, iron-carbon alloys (steel and cast iron) and alloys with high silicon content can be obtained. The results of the work can be used in development of theoretical and technological foundations for the processing of copper smelting slags, which are not processed by existing technologies.

Development of rolling stock, increase in the speed of transportation, load-bearing capacity of highways and their length requires constant improvement of the production technology for railway rails. Modern rail-beam mills have in their composition a continuously reversible group of stands, which includes universal stands. Rolling of rail profiles in universal calibers is radically different from rolling in two-roll calibers, and at the moment is not well studied, both theoretically and practically. The article defines the conditions for feasibility of the rolling process in universal calibers with a pair of non-drive rolls, taking into account the values of active (reserve friction forces) acting from the drive rolls and reactive forces from the non-drive rolls and roller fittings. The energy balance method solves the problem of determining the back-up force required for deformation in non-drive rolls. When solving the equation of equilibrium of forces in the deformation center formed by the drive rolls, the reserve of friction forces is defined, the magnitude of which largely determines the possibility of the rolling process. Theoretical dependences are obtained for estimating the power balance during rolling in universal calibers of modern rail-beam mills, taking into account the reserve of friction forces provided by the drive rolls and the support required for deformation in non-drive rolls. Information about the force conditions in a universal caliber is necessary to analyze the feasibility of the rolling process in it under various deformation modes and to clarify the drawing coefficients for elements of the resulting profile. Dependencies are proposed that allow estimating the consumption of the reserve of friction forces for the operation of roller fittings serviced by universal caliber. The well-known formula of A.I. Tselikov and A. I. Grishkov on the definition of broadening was clarified in relation to rolling in universal calibers with two non-drive rolls. The support from the non-drive rolls side effects the change in size of sole and head of the rail profiles.

The conducted studies have determined the regularities of influence of rolling parameters of billets and grinding balls in their production from the rejects of K76F rail steel on probability of defects formation during deformation. Modeling of the rolling process of high-grade billets from the rejects of continuously cast ingots of rail steel of the specified grade in DEFORM-2D software package allowed us to establish a significant effect of such parameters as: partial coefficients of drawing along the transfer bar, frequency of rolling edges, and rolling temperature, on the probability of defect formation, characterized by the maximum value of the Cockcroft-Latham criterion in cross section of the rolls. It is shown that an increase in the coefficients of drawing (compression) along the transfer bar, due to intensification of the rolling mode and an increase in frequency of edging, reduces the likelihood of defects forming during rolling by reducing the temperature inhomogeneity along the rolls section. The established effect of temperature increase on reducing the probability of defects formation is due to an increase in plasticity of the considered rail steel. Based on the data obtained, general recommendations are formulated on the directions of improving the rolling modes of billets from the rejects of rail steels and restrictions on their application in practice. Based on the results of modeling the rolling of grinding balls from the rejects of rail steel on a helical rolling mill, a significant effect of an increase in the deformation temperature on reduction of cracking in the balls axial zone, due to an increase in the steel ductility, was established. Therefore, a new mode of rolling grinding balls from the rejects of K76F rail steel was developed, which provides an increase in impact resistance of grinding balls while maintaining high surface hardness. Effectiveness of this mode is confirmed by the results of its pilot testing in conditions of the ball rolling mill at JSC “Guryevskii Metallurgical Plant”.