In practice, so-called static models are widely used to show the oxygen converter process, describing changes in output parameters based on information about input parameters for each individual production cycle (heat). Additionally, the models used in the final period make it possible to ensure a more accurate hit within the specified limits in terms of temperature and carbon content in the metal. In this case, information on the results of intermediate measurement of metal parameters by a probe tuyere, which is carried out during the consumption of 80 – 95 % of the total oxygen consumption for heat, is used as the initial information. To describe the behavior of an object during the process from the beginning to the end of the production cycle, it is necessary to build a model based on the patterns of phase interaction in an open system (oxygen converter – BOF). In this paper, an attempt is made to construct such a model using the concept of a stationary nonequilibrium state and the results of physical and mathematical modeling of the system when the contact area of two non-miscible liquids changes when exposed to a gas jet. When forming the model, we proceeded from the presence in the melt of two main reaction zones of oxidation of components, which, according to modern concepts, determine the mechanism of processes and hydrodynamics of the melt during blowing of the converter bath. For each selected zone, to a large extent, the characteristics of mass transfer during different periods of the operation, depending on the current parameters of the interacting phases, determine the rates of chemical reactions. The results of checking the adequacy of the model using practical data allow us to conclude that the model can be used to study the blowing process in a BOF.

In order to substantiate the possibility of producing grinding balls of the 5^th hardness group and to stabilize the production of balls of the 4^th hardness group in an operating ball rolling mill, a series of theoretical and experimental studies were conducted. Based on the results of computer modeling of the production process of grinding balls with a diameter of 60 mm, the authors determined the patterns of formation of the metal stress state during cross-screw rolling of balls made of standard steel Sh2.3 and experimental economically alloyed steel Sh76KhF. A decrease in the temperature of billet discharge from the heating furnace within the permissible range of its change according to current technology (880 – 1000 °C) leads to a significant increase in stress intensity over the entire surface of the balls during rolling, which increases the load on the equipment of the rolling stand and wear of the roller calibers. Additionally, the simulation shows that after the end of rolling, there is a significant (up to 80 °C) temperature unevenness on the balls surface, which, however, is almost completely eliminated after the balls are cooled on the conveyor before quenching. In the case of rolling balls from the billets with a discharge temperature from a heating furnace of less than 980 °C, the balls surface temperature before quenching is lower relative to the recommended range, ensuring the production of products with specified properties, which is confirmed by metallographic and durometric studies. Based on the results of the conducted research, a new mode of grinding balls production was developed with the temperature of billet discharge from the heating furnace increased to 980 – 1030 °C. Pilot testing of the new rolling mode showed that its use guarantees producing grinding balls of the 4^th hardness group according to GOST 7524 – 2015 in their production from standard steel Sh2.3 and producing balls of the 5^th hardness group using the developed economically alloyed steel grade Sh76KhF. At the same time, balls made of both steel grades under consideration have increased impact resistance.

The paper analyzes energy consumption during steel wire drawing for pass schedules with different number of passes. The authors compare wire drawing pass schedules that have different number of passes and the same total reduction. Dependences of the wire drawing process para­meters on the number of passes were calculated. The methods for calculating the uniform and redundant deformation work, the friction forces work during wire drawing in monolithic dies are presented. The authors obtained the dependences of uniform and redundant deformation work, as well as the friction forces work and total work on the passes number of the pass schedule. A significant proportion of energy consumption is due to redundant work. Such wire drawing deformation measures as reduction and elongation do not consider redundant deformation. The redundant deformation work depends on the shape of the deformation zone characterized by the ∆-factor, which is equal to the ratio of the average height to the average length of the deformation zone. It was established that energy consumption calculations for wire drawing without taking into account redundant deformation lead to energy consumption underestimation. The paper provides criteria for selecting the number of passes, taking into account the energy consumption for wire deformation during wire drawing. It was determined that an increase in multistage wire drawing number of passes with the initial and final wire diameters equal leads to an increase in energy consumption for wire deformation and friction on the wire-die contact surface. The redundant deformation share in the increase in energy consumption for wire drawing was 68 %, the friction forces share was 32 %. The authors provide recommendations for choosing the optimal pass schedule based on the results obtained. 

The article considers the issues of obtaining thin-walled parts with arc-shaped elements for small devices and units in small-scale or single production using the principles of prototyping, which has recently been widely used to test and evaluate ideas at the earliest stage of development, and in some cases, to verify the functioning of a prototype device. Taking into account the requirements for the parts quality, the technology of stepped bending is chosen, which uses a set of consecutive V-shaped bends to obtain a given curvature of the billet. The basic principle of the multi-stage forming process is to replace the bending arc with a polygon, each side of which is a rectilinear section of sheet material of a given length, while bending the sheet metal using a small-radius punch. The accuracy of forming an arc segment using polylines depends on their number. The greater the number of bending steps, the smoother the profile is formed, but the bending process becomes more laborious and technically complex. Therefore, the technical and economic indicators of the process depend on correct choice of the number of steps. With this bending method, it is difficult to avoid a prismatic structure on the billet surface; in this case, the traces of step bends will be more noticeable on the inside of the bent sheet material compared to the outside. Using stepped bending technology, various metal parts of the prototype of the universal plasma low-temperature sterilizer of Plaster Med TeCo series were manufactured, which allows fast, safe and effective sterilization of a wide range of medical equipment. As an example, the use of stepped bending technology of a stainless steel sheet billet for the production of a thin-walled bumper for a sterilizer door is considered.

The modern metallurgical industry, especially in the field of ferrous metallurgy, faces significant challenges in improving energy efficiency, reducing waste volumes, and minimizing environmental impact. One of the promising directions is the use of high-silicon silumin alloys, which, due to their high strength, wear resistance, and thermal stability, are finding increasingly broad applications, including their capability for multiple recycling. This paper analyzes the composition and physico-mechanical properties of these alloys and their role in technological processes of ferrous metallurgy, such as smelting, casting, heat treatment, and mechanical processing. Innovative approaches aimed at reducing the energy intensity of production operations, minimizing waste, and creating closed production cycles are examined, which is particularly relevant for ferrous metallurgy, where waste volumes are traditionally high. Examples of application of high-silicon silumins in the production of casting molds, wear-resistant coatings, and structural materials for heavy industries are provided. Special attention is given to recycling and waste utilization technologies at metallurgical enterprises, contributing to lower production costs and increased competitiveness. Thus, the use of high-silicon silumin alloys demonstrates potential for shaping environmentally friendly, energy-efficient, and economically sustainable processes in ferrous metallurgy.

The article discusses a new method for estimating the amount of dust emitted from the converter bath during oxygen blowing of phosphorous hot metal. This method allows one to determine how technological solutions and blast modes affect the environmental performance of the production process. The study identified the causes of increased dust emission and developed the solutions to improve the environmental performance of the plant. Dust and gas emissions from the converter shop fall into two categories: organized and disorganized. Organized emissions are captured at the outlet of the converter mouth, and disorganized emissions occur periodically during cast iron casting, scrap loading, metal and slag discharge. These emissions contain dust, heat, carbon monoxide, nitrogen and sulfur oxides, and aluminum fluorides. Resource-saving technology using inactive slag reduces emitting of dust and gases by using active foamed slag at the initial stage of blowing and reducing lime consumption. Matching the gas volume to the exhaust duct’s through-put reduces dust removal by 30 – 40 % and unorganized emissions by 83 %. Reduction of carbon monoxide emissions is achieved by increasing the rate of rise in the CO concentration to the ignition limits, followed by afterburning on the “flare” and organizing melting with a shortened first heating period. Reducing the phosphorus content of cast iron to 0.3 wt. % decreases lime consumption from 143 to 77 kg/t of steel,
the duration of blowing and heats by 10 – 16 %, lime production and increases the productivity of converters. A comprehensive approach to reducing dust and gas emissions includes optimizing processes, introducing new materials and technologies, and monitoring and analyzing performance indicators. This improves the environmental situation and increases production efficiency.

The С235 steel samples were dry-slid along the counterbody (C45 steel) according to the pin-on-ring configuration scheme (shaft-pad type) at sliding speeds of 0.75 – 8.0 m/s under a contact pressure of 0.13 MPa. The need for such an experiment is justified by the lack of indicative data on the tribotechnical behavior of steel in sliding contact with steel in the absence of oxidation products in the contact space. Temperature of the sample holder does not exceed 35 °C at all sliding speeds. This allows us to assume that there are no oxidation products on the contact surfaces. Formation of the transfer layer is visually observed in sliding only at low speeds: 0.75 – 1.3 m/s. The friction coefficient decreases during the formation time of the transfer layer and reaches a final value of about 0.4. The sliding surfaces of the samples contain signs of adhesive interaction at all sliding speeds. Adhesion is particularly pronounced on the sliding surface of the sample at a sliding speed of 2.5 m/s. The friction coefficient at this sliding speed has significant fluctuations around 0.8 ± 0.1. At the same time, there is a high rate of wear. Dependence of wear intensity on the sliding speed has maximum at a sliding speed of 2.5 m/s. The lowest wear rate is observed at a sliding speed of 5.0 m/s and at friction coefficient of about 0.7 ± 0.05. A low amplitude of friction coefficient fluctuations (0.7 ± 0.03) is observed when sliding at a speed of 8.0 m/s. X-ray phase analysis showed that contact layers of the samples at all sliding speeds have only α-Fe phase with a lattice parameter of about 0.287 nm.

Creation of compounds of dissimilar metals is one of the priority areas in the field of obtaining special structural materials with a unique combination of properties. In connection with development of new production processes, the question arises about the influence of structural-phase heterogeneity of multilayer materials on deformation behavior. In particular, an important scientific problem is the localization of plastic flow. The digital image correlation (DIC) method was used to analyze the nature of localized plastic deformation in the bimetallic composite austenitic stainless steel/low-carbon steel manufactured by additive beam technology. It was found that in all layers of the bimetal, plastic deformation develops locally in each layer of the studied composite according to the loading stages. It is shown that during deformation of a bimetallic compound, the appearance of the yield plateau stage (n = 0) and, accordingly, the Lüders deformation is suppressed, despite the significant content of a low-carbon steel layer in the bimetal. In the parabolic section with the hardening index n = 0.5, the components of local elongations ε_xx form a stationary periodic distribution of localized deformation zones. With the onset of the stage with n ≤ 0.5, a high-amplitude deformation zone is observed in the transition layer, which coincides with the place of future sample fracture. In this case, the growth of the amplitude of localized deformation in this zone begins at the parabolic stage of the loading diagram. Structural heterogeneity at the interface in the bimetallic composite austenitic stainless steel/low-carbon steel is the source of the initiation of a fracture crack in the austenitic steel layer. Apparently, the initiation of the destruction zone in the transition layer is associated with the formation of a brittle carburized layer, which occurs due to the diffusion of carbon through the interface low-carbon steel – stainless steel.

The study of the cast structure of castings makes it possible to optimize the technological parameters of the casting process and improve the quality of cast billets. Electron microscopic studies of nonmetallic inclusions and X-ray spectral analysis of their micro-volumes in metal plates cut from defective sections of a massive casting were carried out. The “fresh” fractures of impact samples with a sharp V-shaped incision destroyed at –60 °C were investigated. It was found that there are practically no oxide films and non-metallic inclusions at the boundaries and in the body of the casting grains. The latter occur on the inner surface of micropores or near them at the edge, and aluminum carbonitrides are present at the grain boundaries or in their body. Determination of chemical composition of non-metallic inclusions in micro-volumes of the order of 1 µm³ allowed us to establish their nature and possible causes of their appearance, as well as formulate practical recommendations for the prevention of visually observable defects in a massive casting. To improve the quality and reduce the number of micropores occurring in the casting, it is necessary to use a cleaner charge that does not contain zinc. Zinc has a low boiling point (907 °C [10]), and, when casting the mold, its vapors, along with other gases, rise to a casting head, under which, as a result of crystallization, they settle in pure form or in the form of ZnO-type compounds on the walls of the resulting micropores, shrinkage porosities, cavities. In addition, it is necessary to remove the slag more carefully so that it does not participate in pores formation, and its particles do not precipitate in or near the pores in the form of magnesia spinel, calcium and manganese sulfides, iron, aluminum, calcium oxides, etc. It is also required to limit the residual aluminum content in steel after its deoxidation to 0.03 %, as is customary in metallurgical production, and to minimize the resin content in the mold material.

The X-ray method was used to study martensitic transformations in different areas on the fracture surface of the samples made of coarse-grained (CG) and ultrafine-grained (UFG) Fe – 0.02C – 18Cr – 8Ni steel after torsion testing. The fine structure of UFG steel was analyzed on JEM-2100 transmission electron microscope (TEM). The authors carried out the steel hardness tests on TN 300 hardness tester. Static tension of cylindrical samples with a diameter of 3 mm was performed at a temperature of 20 °C on N50KT universal testing machine. Torsion testing of cylindrical samples with a working part diameter of 10 mm and a length of 100 mm was carried out at a temperature of 20 °C using  MK-50 unit. The equal-channel angular pressing (ECAP), forming UFG structure, improves the mechanical properties of steel under tension and torsion, and also helps to stabilize the austenitic structure of Fe – 0.02C – 18Cr – 8Ni steel under torsion. 100 % of α-martensite is formed on the fracture surface of CG steel samples, regardless of the X-ray diffraction area. On the fracture surface of UFG steel samples, the maximum amount of α-martensite (30 %) is formed in the peripheral area of ​​the fracture; the minimum amount of α-martensite (15 %) – in the fracture central part. The authors made a comparative analysis of the martensitic phases distribution on the samples fracture surface after torsion testing with the martensitic phases distribution in the samples of the same steel after severe plastic deformation by torsion (SPDT), when both ε- and α-martensite are formed. The absence of ε-martensite on the fracture surface of the samples made of CG and UFG Fe – 0.02C – 18Cr – 8Ni steel during torsion is associated with an insignificant pressure for this type of loading, less than in the SPDT process.

The share of local iron ore raw materials of metallurgical enterprises of the Ural region is 50 – 60 %. The rest is brought from Central Russia, the Kola Peninsula and Kazakhstan. The issue of replacing imported raw materials with local, cheaper ones, is very relevant. The extraction of siderite iron ore of the Bakalskoye deposit (Southern Urals), the reserves of which are about 1 billion tons, is many times less than the mining and geological conditions allow because of the insignificant demand for this raw material due to its low quality. The high content of magnesium oxide in the ore makes blast furnace smelting difficult or impossible using more than 20 % of siderites in the charge. The basis of any blast furnace slag is a four-component system CaO – SiO₂ – Al₂O₃ – MgO with the following composition, wt. %: 30 – 40 SiO₂, 31 – 49 CaO, 3 – 18 MgO, 7 – 20 Al₂O₃. The melting point of such slags is 1280 – 1320 ℃. At a temperature of 1450 °C, their viscosity is about 0.5 Pa·s. An increase in the magnesium oxide content (>20 %) leads to a sharp increase in melting point of the slags, reduces the crystallization interval and makes them unstable. In this regard, the materials made from siderite ore using various technologies for preparing them for blast furnace smelting (raw ore, roasting-magnetic separation, agglomeration) are introduced into the blast furnace charge only as additives. Their share does not exceed 20 %. The effect of boric anhydride on the viscosity of high-magnesia blast furnace slags containing 15 – 36 % MgO was studied using modern methods of statistical processing of experimental data. It was shown that addition of boric anhydride to the initial charge allows to reduce the melting point of the slag and to increase the crystallization interval. This makes it possible to conduct blast furnace smelting on slags containing about 40 % MgO, which corresponds to a siderite share of 40 – 50 % in the initial charge.

The article provides a detailed analysis of domestic and foreign research works on the stress-strain state in a shell mold during production of metal castings. Experimental and theoretical studies are important for improving the technology of producing high-quality foundry products. In this paper, the problem of reducing the stress-strain state in a cast ceramic shell mold is formulated and solved by reducing the resulting tensile stresses on its outer surface by performing temperature seams (recesses). The parameter determining crack resistance is the normal tensile stress σ₂₂, which occurs on the outer surface of the shell mold at the initial moment of casting the metal and cooling the steel casting in it. The problem under conside­ration is axisymmetric. The shell mold has spherical and cylindrical sections. The authors formulated the objective function, provided a numerical scheme and a developed algorithm for solving the problem based on the equations of linear elasticity theory, equations of thermal conductivity and proven numerical methods. The result of solving the model problem is the optimal geometric location of the temperature seams in the form of annular recesses and their number. Stress fields are shown in the form of plots along the sections of the area under consideration in the presence and absence of temperature seams. For the sake of convincing the proposed method (performing temperature seams), the test example considers the most rigid option, which does not use the factors established earlier in previous studies that affect the reduction of tensile stresses on external surface of the shell mold. The results obtained characterize the resistance of ceramic casting mold to cracking and demonstrate the feasibility and effectiveness of the proposed technology for manufacturing ceramic casting shell molds.

For 13G1S-U sheet steel and large forgings made of heat-treatable 38KhN3MFA-Sh steel, produced by existing technologies, the possible con­sequences for quality assessment of metal products were analyzed related to changes in the number of samples used in testing a single product unit (batch, forging). Based on the calculation of skewness and kurtosis coefficients, the authors estimated the change of distribution type of impact strength values accompanying the change in the number of samples. The sampling of impact strength range values ​​obtained from testing two samples (three possible paired combinations) per unit of products were compared using the Student’s and Smirnov’s criteria, both among themselves and with the original sampling (three samples for evaluating one batch of sheet). The obtained results also showed that in conditions when the statistical nature of values distributions of the metal products quality parameters differs from the normal distribution type, it is necessary to use the criteria of nonparametric statistics. The risks of possible loss of information on the metal products’ quality when reducing the number of samples tested within a single batch were assessed. In order to obtain adequate results of statistical analysis, it is necessary to identify and eliminate possible side effects that distort results of analysis: trends, seasonal fluctuations, and data recording errors. For metal products characteri­zed by the developed heterogeneity of structures, obtaining objective information on the toughness reserve of steels can be obtained on the basis of micromechanical tests of samples whose dimensions are comparable to the scale of structural heterogeneity. The obtained results can be useful in the statistical analysis of production process and product control databases in metallurgy to obtain reasonable technological recommendations (within the framework of operation of the end-to-end quality management system) aimed at improving the uniformity of metal product.

The control of blast furnace hearth lining is of critical importance in ensuring efficient and safe operation of blast furnace production process. Hearth lining plays a fundamental role in protecting the blast furnace walls from high temperatures and chemically aggressive slag melt. Early detection of high wear areas allows planning of preventive maintenance, thereby minimizing downtime and lost productivity. Furthermore, it contributes to the efficient use of resources by optimizing the replacement of damaged lining sections, thus avoiding unnecessary expenditure on preventive measures. The paper presents a three-dimensional unsteady model of blast furnace hearth, developed based on thermocouple data. This model facilitates estimation of the crucible heat-up and temperature distribution in the crucible masonry in three-dimensional and two-dimensional (graphical) forms. Estimation of the hearth lining burnout is achieved through the utilization of readings of the thermocouples installed in the hearth lining of blast furnace in the area encompassing the three lower refrigerator belts. Implementation of the mathematical model is permissible at any juncture following the overhaul of the first discharge. If a sufficient amount of time passed since the blast furnace was blown in, and there is a possibility of burnout or skull formation in the hearth lining, it is also necessary to utilize the results of ultrasonic control (USC) of the blast furnace lower part. The mathematical model of the blast furnace hearth condition enables informed decision-making by users regarding prevention of the emergency situations related to lining burnout, thus demonstrating its potential as a tool for enhancing the efficiency and safe operation of blast furnaces.