The conducted studies determined the patterns of influence of chemical composition and deformation parameters of ball steels with experimental chemical composition on their deformability. The development of experimental chemical compositions of ball steels was carried out based on the existing experience of domestic and foreign researchers, taking into account the possibility of further application of the obtained results for ball steels of standard grades. The studies were carried out using a specialized laboratory installation by the method of hot-rolling samples. An increase in the carbon content in the range of 0.72 ‒ 0.85 %, manganese in the range from 0.72 to 0.85 %, chromium in the range of 0.38 – 1.71 % and nickel in the range from 0.08 to 0.87 % has a significant effect on increasing the deformation resistance of steels. At the same time, the quantitative effect of carbon content in the steels on their deformation resistance is much more pronounced in relation to manganese, chromium and nickel. It was determined that a decrease in the deformation temperature from 1200 to 900 °C, an increase in the deformation rate in the range from 1 to 10 s^–1 and true deformation in the range 0.05 ‒ 0.35 cause an increase in the deformation resistance of ball steels, regardless of their chemical composition. The influence of all these parameters on the deformation resistance of steels has a pronounced nonlinear character and the deformation temperature has the greatest relative influence on the deformation resistance. The data obtained are summarized in the form of a multiple regression equation, which establishes the quantitative relationship between the resistance of steel to deformation with its chemical composition and deformation para­meters. Verification of the adequacy of the obtained equation in relation to the rolling conditions of ball steel billets of standard grades at the continuous medium-grade mill 450 of JSC EVRAZ United West Siberian Metallurgical Plant confirmed the possibility of using it to predict the energy-power parameters of rolling ball steels of various chemical composition.

The conversion of non-magnetic or weakly magnetic constituents of iron ores into the magnetic ‘magnetite’ phase was investigated using partial reduction by hydrogen at temperatures below 400 °C. The examined four commercial iron ores from Russian and Chinese deposits have significant differences in their compositions and morphologies. All ore samples were crushed using mechanical abrasion in a stamp and sieved with a mesh size of 1.5 mm. Reduction was carried out in a tube furnace under isothermal conditions at 375 and 400 °C for one hour. To study the kinetics of the reduction process, non-isothermal studies of selected ores were сonducted using a thermogravimetric analyzer with heating to 800 °C at a heating rate of 10 °C/min in hydrogen flow. The authors made a detailed characterization of the annealed products using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy to determine the magnetic characteristics of initial and partially reduced ores. X-ray diffraction patterns showed hematite peaks in the initial samples; both magnetite and metallic iron peaks were detected in the samples reduced at 375 and 400 °C. Such behavior was observed for all four samples under investigation. The most important result of the study is the confirmation of an order of magnitude increase in saturation magnetization for hematite ores, in addition the reduced ore samples show soft magnetic properties with average coercive force values ​​of approximately 20 kA/m. Application of the low-temperature reduction by hydrogen to iron-containing ores is very promising for production of the materials that could later be subjected to enrichment using magnetic separation methods.

Metal resistance to the formation of contact fatigue defects and wear development has a great influence on the consumer properties of rails. The most significant factors limiting the service life of rails in curved sections of the railway track are wear of rails of the outer threads and development of contact fatigue defects in the inner threads of the track. In this regard, methods of reliable laboratory assessment of the rail metal resistance become important in the development of new products. The paper describes the change in the nature of damage to rails of various hardness categories by contact fatigue defects, and evaluates their wear resistance. The study of defects and forecasting of the rail resource require an integrated approach. The paper provides a brief description of modeling the conditions of formation and accumulation of contact fatigue defects. The parameters under consideration have an effect on the wear resistance of rail metal of various chemical compositions. During the testing, the rails microstructure and the nature of crack growth change. The authors made a comparative analysis of the data obtained characterizing the wear resistance of rail steels of various hardness categories. The basis of the methodology for assessing the wear resistance of railway rails is the physical modeling of adhesion-deformation mechanism of friction of the samples on a roller friction machine (tribometer). During laboratory tests of the studied categories of rails, the friction machine automatically outputs and records a number of computational parameters shown in the work. The conducted research is promising from a practical point of view. The results obtained can be used to develop a theory to increase the service life of differentially hardened rails produced by JSC EVRAZ United West Siberian Metallurgical Plant.

To increase the energy-technological efficiency of a ferroalloy furnace, the author studied the smelting of 45 % ferrosilicon by a carbon-thermal method. In some cases, methods for measuring and changing the specific electrical resistance of charge materials at temperatures up to 1900 K are used to study the technology of smelting ferroalloys for smelting manganese alloys from various ores, carbonaceous ferrochrome, ferrosilicon, ferrosilicon manganese and ferrosilicon aluminum. For a series of heats of 45 % ferrosilicon, measurements of the useful voltage, electrode current, and power factor were carried out. As smelting progressed, the bath resistance was calculated and for the reaction melting zone (melting crucible), the specific electrical resistance in the single-electrode version of the furnace was determined at various sub-electrode gaps. Smelting using technology with an increased sub-electrode gap was performed in a large-scale experimental electric furnace with a capacity of 130 ‒ 290 kV·A. As a result, it was found that an increase in the sub-electrode gap from (0.6 ÷ 0.9) to 6.0 of electrode diameters leads to the effect of a 2.5-fold increase in resistance, voltage and power in the bath (each indicator), but at the same time to a slight decrease in the specific electrical resistance of the melting zone of the furnace with a constant diameter (150 mm) of the electrode. The optimal sub-electrode gap (electrode – substrate distance) in the bath of a single-electrode furnace was determined by changing the specific electrical resistance. The optimal value is 3.33 of the electrode diameter. Assuming deviations of about ±5 % of this value, it is possible to efficiently smelt 45 % ferrosilicon in the range of 3.2 ‒ 3.5 electrode diameters for the sub-electrode gap during the ore recovery process with a closed arc.

The resistance of metals and alloys to plastic deformation has functional properties, since it depends on the history of the development of deformation over time. This is especially true for hot deformation processes. At the same time, complexity of the mathematical description and lack of the necessary experimental equipment for a long time did not allow us to design functionals of this type. Currently, due to the emergence of multifunctional research complexes like Gleeble, such an opportunity has appeared. Accordingly, a methodology was developed to study the functional properties of the resistance of metals and alloys of plastic deformation, which was applied to the study of 12Kh18N10T steel. The choice of steel grade is due to the fact that the behavior of austenitic stainless steel during plastic deformation differs significantly from carbon steels. On the other hand, at present, more and more attention is being paid to the production of metal products from stainless steels. This is due, on the one hand, to the tighte­ning of the operating conditions of metal products, the development of new areas of their application and, on the other hand, a fairly high share of imports in the market of products made of austenitic stainless steels. Therefore, the study of the technological properties of such metals and alloys is relevant. At the same time, it should be noted that the most significant functional properties of the metal resistance to plastic deformation are manifested during hot deformation under continuous rolling conditions. Therefore, in this paper, the temperature range of hot plastic deformation is investigated. The results obtained can be used to determine the energy-power parameters in such processes as continuous rolling of strips in the finishing groups of strands and continuous rolling of sleeves in the lines of modern pipe rolling units.

The study considers ways to increase the efficiency of reduction of iron oxides from man-made waste (dust from electric arc furnaces) using mechanochemical activation (MCA), grinding and pressing. The analysis of chemical and phase compositions of the dust samples was carried out, which made it possible to identify their potential for processing. The experiments included a study of the effect of grinding and pressing at pressures up to 300 MPa on the materials’ phase composition, as well as an assessment of the effects of coke addition during MCA. To study the effect of pressing pressure on the reduction processes, briquettes were fired at a temperature of 1200 °C. The results showed that the degree of iron metallization increases with an increase in pressing pressure: concentration of metallic iron reaches 19 % at a pressure of 300 MPa, which is higher compared to 17 % in the initial state without pressing. The novelty of the work lies in optimizing the pressing parameters and demonstrating its effect on the iron reduction process. The proposed conditions make it possible to increase the efficiency of processing man-made waste, which can be used to improve the environmental and economic components of production.

The work is devoted to the study of the inhomogeneity of deformation of steel samples with laser surfacing. Highly nitrogenous austenitic stainless steel of the 08Kh18N6AG10S grade was selected as the substrate material in the state as received. To improve the mechanical properties of structural elements that operate under conditions of impact and abrasive wear, a surfacing of Ni–7Cr–6Fe + 60 % WC composite powder was applied to the steel. The surfacing was carried out with a change in the power of laser radiation from 1 to 3 kW and a change in the scanning speed from 0.005 to 0.040 m/s. The penetration depth of a single roller decreases with increasing scanning speed. The microhardness varies widely in the surfacing thickness (from 7,000 ± 80 to 13,500 ± 70 MPa) and decreases with increasing the scanning speed. Using the speckle photography method in the process of uniaxial extension of flat samples, it was found that the modes of laser surfacing also affect the level of inhomogeneity of deformation of micro-volumes of the deposited layer and the substrate. At the elastoplastic transition, the coefficient of variation of local deformations in the sample increases with an increase in the specific energy of laser surfacing. Coatings made of Ni – Cr – Fe + WC composite powder, obtained by laser surfacing under specified conditions, make it possible to increase the hardness and service life of structural elements of rotary controlled systems made of 08Kh18N6AG10S steel.

The authors investigated the microstructure and mechanical characteristics of 56GM steel-based composite produced by wire electron-beam additive manufacturing with the addition of W + WC(Ni) powders during printing. The analysis demonstrates that 56GM/(W + WC(Ni)) composite alloy is characterised by a gradient structure consisting of 56GM base layer, 56GM – 56GM/(W + WC(Ni)) intermediate layer and  56GM/(W + WC(Ni)) composite layer. The base layer of 56GM steel is characterized by a multidirectional acicular structure, which corresponds to the ferrite-martensite state. In 56GM – 56GM/(W + WC(Ni)) intermediate layer the acicular structure becomes less pronounced. In 56GM/(W + WC(Ni)) composite layer an equiaxed grain structure is formed, with an average grain size of 8.59 μm, along the boundaries of which cracks are observed. WC particles are located mainly along the boundaries of small grains and in small quantities inside the grains themselves. It was found that 56GM/(W + WC(Ni)) composite is mainly composed of α-Fe (~80.6 vol. %), Ni (~6 vol. %), WC carbide phase (~10.3 vol. %) and γ-Fe (3 vol. %). The structure and properties of initial 56GM steel change both in the area of direct addition of alloying powder and in the underlying layers due to diffusion processes and infiltration of W + WC(Ni). Microhardness values increase from ~3.5 GPa to ~6.5 GPa with distance from the substrate to the composite layer. In uniaxial tensile tests, the ultimate tensile strength and yield strength values reached 1100 – 1200 MPa and 835 MPa in the intermediate layer, respectively.

The desire of modern manufacturers to reduce the cost of producing goods leads to an increased search for ways to obtain the raw materials for future products more efficiently. One promising method for obtaining raw materials is electric arc surfacing (WAAM), which is discussed in this paper. The aim of the study was to investigate the effect of electric arc surfacing on the structure and fatigue strength of 30CrMnSi steel. To obtain the samples, two walls were surfaced according to the specified modes: I = 150 A, U = 25 V, Q = 600 J/mm (mode 1) and I = 110 А, U = 17 V, Q = 300 J/mm (mode 2). During the study of the walls microstructure after milling, it was found that when the metal is surfaced according to the mode 1, large accumulations of technological defects such as pores and bad welding form in the material. When the metal is treated according to the mode 2, these macroscopic defects are practically not detected. During optical emission analysis, it was observed that during the surfacing process, alloying elements are consumed and the carbon content decreases most actively. It should be noted that the burnout of elements occurs more actively when the metal is surfaced using the mode 1. This may be due to the higher energy input in this process. A predominant ferrite-sorbite structure was found in the metal surfaced using the mode 1. However, local ferritic colonies were revealed on the surface of the samples due to their height. The microstructure of the samples produced using the mode 2 is mainly composed of ferrite and pearlite. Ferrite is isolated as closed grids along the boun­daries of the austenitic grains, and traces of a Widmanstetten structure can also be seen. Perlite is present both as highly dispersed plates and partially spheroidized colonies. Despite the fact that the structure of the samples produced using the mode 1 is generally considered to be more favo­rable in terms of material properties, the fatigue strength of the samples produced according to the mode 2 exceeds that of the mode 1 by an average of 70 %. This may be due to the stronger influence of technological defects on the metal fatigue resistance than microstructural ones.

The subject of the study is a metal composite obtained by electric arc surfacing in argon of corrosion–resistant steel on low-carbon steel. Powdered chromium-nickel steel was deposited with an increased content of silicon and molybdenum relative to the traditional composition. In this work, we studied the elemental and structural-phase compositions, as well as the mechanical properties of both components of the material and the composite as a whole in the initial state and after annealing at 680 °C for 3 h. The main part of the corrosion-resistant component is a two-phase auste­nitic-ferritic mixture with a ratio of 65 % HCC phase and 30 % BCC phase. The material has high microhardness (more than 4000 MPa). The highest microhardness (4550 MPa) is observed in a narrow strip of deposited metal with a width of 25 μm, where the phase composition is represented by martensite (BCC), and austenite is absent. The transition across the boundary into carbon steel is accompanied by a decrease in microhardness to 1225 MPa. Here, a decarbonized zone with a width of 180 μm was formed near the fusion line. The resulting non-equilibrium stress-strain state of the composite led to low strength, low plasticity and brittle fracture of the deposited layer during tensile testing. After annealing, microstructure of the corrosion-resistant component became more uniform in size of both austenitic and ferritic structural elements. As a result of these transformations, internal stresses decreased and microhardness decreased to 3100 MPa. At the same time, the width of the decarbonized zone in the base metal increased. All these changes led to the fact that, although the tensile stress of the annealed material increased by 8 %, and the deformation to rupture – by 27 %, however, nature of the fracture remained brittle and rupture still occurs along the deposited layer. This is determined by the austenitic-ferritic phase composition of the stainless component, which, in turn, is determined by chemical composition of the deposited material.

The authors investigated the microstructure and mechanical properties of wear-resistant coatings applied by the method of gas-thermal spraying with heating of the metal to a liquid state and its subsequent spraying with a gas jet. Nowadays, thermal spraying is increasingly an alternative to various methods of surfacing due to the high costs of consumables, the complexity of maintenance and safety during repairs. By this method, it is possible to reliably solve a variety of technological tasks, which include spraying of wear-resistant, antifriction and corrosion-resistant coatings; alitizing by spraying (increasing heat resistance); increasing the size of products; surfacing and soldering; elimination of casting defects; manufacture of molds, etc. The tribotechnical properties of the vibration damper rod of a railway carriage with reinforcing surface layers applied to the working surface by methods of gas-thermal spraying with 40Kh13 steel and galvanic chromium plating were investigated. Structure and thickness of the coatings, microhardness distribution in the coating-substrate zone, as well as the features of the coatings destruction under the same test conditions were studied. The criterion for comparing the coatings’ wear resistance was the operating time of the samples before the beginning of the coating destruction. Wear of the rollers was determined by the change in diameter, and wear of the pads – by the depth and width of the grooves formed on their surface during the experiment. The coating applied to the vibration damper rod by spraying 40Kh13 steel wire has high wear resistance in conditions of boundary friction with grease and can be an alternative to electroplated chrome coating. The high wear resistance of the coating makes it possible to recommend it for restoring the dimensions of worn parts and increasing the durability of new ones, as well as for replacing special anti-friction bearing alloys.

The authors investigated the patterns of fracture during impact bending tests and determined the values of impact strength and temperature of the ductile-brittle transition in temperature range from –196 to 100 °С of heat-resistant 12 % chromium ferritic-martensitic steel EP-823 in structural states after traditional heat (THT) and high-temperature thermomechanical (HTMT) treatments. After THT, temperature of the ductile-brittle transition T_dbt is approximately –45 °С, after HTMT – approximately –40 °С. At these temperatures, the impact energy (KCV) after THT is approximately 36 J/cm², after HTMT – 32 J/cm². Fractographic studies conducted by scanning electron microscopy of the fracture features of impact steel samples after two treatments (THT and HTMT) in the low-temperature test area (at cryogenic temperatures) showed a predominantly brittle nature of fracture, while fracture occurs by the mechanism of a transcrystalline quasi-cleavage. In the temperature range of the ductile-brittle transition, a mixed nature of fracture is observed, which passes through the mechanism of a transcrystalline quasi-cleavage with elements of ductile dimple fracture. In the temperature range from 50 to 100 °С, the extremely ductile nature of the fracture was detected, realized by the transcrystalline dimple fracture mechanism. After HTMT, there is a slight decrease (relative to THT) in the steel impact strength in almost the entire temperature range under consideration and, accordingly, an increase in the temperature of its ductile-brittle transition. This is due to the tests’ geometry, in which the direction of impact occurs in the plane of the layered structure, and it facilitates the formation of delamination cracks.

Currently, a promising area is the development of technologies for sintering or briquetting of converter sludge. Recycling of this sludge into production will allow solving a number of important tasks for modern metallurgy in the utilization of man-made waste, saving raw materials and reducing the cost of steel. The efficiency of utilizing useful components in the composition of briquettes is significantly higher than in any other state (in a fine or polydisperse fraction, in sorted form). In this paper, we consider the development and justification of an integrated approach to thermochemical sintering of converter sludge based on conditioning of iron-containing sludge by non-thermal adsorption dehydration and thermochemical sintering with simultaneous reduction of iron from oxides. Adsorption dehydration to a moisture content of 2 – 3 % is provided by a short-term contact of iron-containing slimes with a porous energy carrier, brown coal semi-coke, which is separated by pneumoseparation and sent for energy technological use, and the iron-containing product mixed with coals is subjected to thermo-oxidative coking. Coking is carried out in an annular furnace with a rotating hearth, where, when temperatures reach 1050 – 1100 °C, a large and durable lump material is formed with 55 – 60 % of the iron-containing product with almost complete reduction. Thermodynamic modeling of converter sludge sintering with coals was carried out. A tool for performing computational experiments using methods of thermodynamic modeling of the studied object was the Terra software package designed to calculate the thermodynamic properties and composition of the phases of equilibrium state of arbitrary systems with chemical and phase transformations. The results of thermodynamic modeling were fully confirmed by the experimental studies. The obtained material is an analog of ferrocox containing 35 – 39 % of iron and 45 – 49 % of carbon, while the zinc oxide content does not exceed 0.017 %.

The report considers the purpose of drawing mills and possible violations of the technological process associated with the design flaws of drawing mill drive. We analyzed the design of a planetary gearbox with a common carrier used in the drive of the stretching drum of a drawing mill. During the operation of such a transmission, there are disadvantages: due to the imbalance of links of the mechanism relative to the central axis, additional dynamic forces arise. This design transmits movement from the leading link to the carrier only through one satellite, the teeth of which perceive all the force transmitted by the torque, which reduces the reliability of the gearbox and the drive as a whole. The design of a three-satellite balanced self-aligning planetary gearbox, free from these disadvantages, is described.

Novotroitsk Plant of Chromium Compounds (NPCC) specializes in the processing of chromite and dolomite ores. Operating experience showed that the loss of operability of the ball mill installed in this workshop leads to unplanned downtime due to the failure of drive elements, which account for 11.3 % of the rated operating time of the workshop. To improve the reliability of technological equipment, it was proposed to replace the existing electric drive with a modern geared motor, which transmits rotation to the mill drum through a gear coupling. As a result of the new drive engineering, it was possible to simplify its design and reduce the labor intensity of maintenance and repair. Additional capital expenditures do not exceed RUB 3.4 million and pay off in less than 3 months.

Using the example of the steelmaking production of JSC EVRAZ United West Siberian Metallurgical Plant, the paper considers the task of synchronous calendar planning in the interval of several planned periods of operation of basic oxygen furnace (BOF), BOF shops, production as a whole, as well as ongoing repairs of BOF for steelmaking production (two BOF shops with two and three BOFs). Scheduled stops of the BOF for repair depend on the actual achieved duration of the lining campaign and production schedules of the units and are performed when the current duration of the BOF campaign reaches a given standard value. Thus, the current duration of the BOF campaign is described by a discrete, nonlinear quasi-periodic function that does not have a fixed period, but has some regularity. Technological limitations were forma­lized, determining the minimum and maximum values of the number of melts per day that each of the workshops can produce with one or two BOFs operating simultaneously. The authors formulated the conditions to avoid performing two “cold” repairs in one shop in one planned period and ensuring daily processing by BOF shops of all cast iron coming from the blast furnace shop. In the proposed mathematical formulation of the problem, it is required to find such schedules of BOF repairs and such calendar plans of their work that satisfy the formulated constraints and optimize the non-linear criterion. The proposed criterion is aimed at ensuring the constant readiness of the shops for implementation of the production program and design productivity. The task is formulated for the conditions of trouble-free operation and stable provision of the shops with liquid cast iron as the main component of the metal charge of BOF smelting.