A historical overview of the development of iron foundry production in the world is presented. The modern level of the material structure in iron casting has an outstripping growth of ductile cast iron grades. The paper describes the features of iron foundry production in Belarus. Technologies and equipment are significantly inferior to foreign ones in terms of productivity and specific resource costs per unit of product. The specific character of Belarus lies in the still widespread use of cupolas, molds from sand-clay mixtures, predominant use of gray cast iron, and small volumes of ductile cast iron production. The total capacity of all foundries is 557.5 thousand tons of casting per year, but the peculiarity is that only about 250 thousand tons per year are actually produced. Development and implementation of the “Program for the Development of Foundry Industries of the Republic of Belarus for years 2017–2030” made it possible to ensure more efficient operation of the foundry industry in the country. In the near future Belorussian foundry industry will reproduce the global trend for critical casting products: transfer to ductile cast iron instead of gray one and further transition to ausferritic (bainitic) cast iron instead of rolled steel.

The substantiated problem of improving the structural properties of agglomerated metallurgical raw materials is associated with the formation of a favorable pore structure in iron ore pellets. The author analyzed various methods for the formation of structural properties of molded dispersed materials in various industries. The paper presents the technological capabilities of promising technologies for production of iron ore pellets based on the heat-power spraying of wet charge on pelletizer’s charge skull and pelletized materials. The physical possibilities of heat-power spraying of wet charge in the forced nucleation and in the process of forming the iron ore pellets’ structural properties are disclosed at the stage of pelletizing. The technical features and production operations of the main technologies for wet charge spraying and the design features of devices for obtaining pellets are shown. The paper describes the experimental unit and technology for the forced nucleation. The macro- and microstructure of the germ mass at forced nucleation were studied. Principles of the formation of regulated structure and improved metallurgical properties in iron ore pellets were substantiated. The article presents the description and characteristics of structural changes on the surface of the sprayed charge layer. A hypo­thesis was put forward about the structural correspondence of geometric dimensions and relief of charge lappings and cavities in the sprayed layer with the nature of porosity and germ structure. The germ mass affects the pellets’ structural properties. The author obtained the dependences of structural changes’ relative values on the sprayed layer surface on pressure of air-charge jet and particle size of the sprayed charge. There is relationship between geometric dimensions of the sprayed charge layer and the structural changes’ size. A probable mechanism of porosity formation in the germ mass during heat-power spraying of a wet charge onto the pelletizer skull was formulated. The aerodynamic characteristics of air-charge jet influence the formation of porosity. New possibilities of heat-power spraying of wet charge can intensify pellets production and improve their quality.

Russia has an impressive titanium mineral resource while the contribution into the global production of titanium concentrates is quite insignificant. The current annual demand of Russian enterprises for titanium raw materials is 40 times higher than its production. To improve and launch the processing of domestic titanium raw materials characterized by low quality and complex polymineral composition, new process solutions are required. These solutions should aim at the full extraction of TiO₂ and related valuable components from the ore deposits whose development is planned or already started (for example, Afrikanda – perovskite-titanomagnetite deposit located on the Kola Peninsula). This report presents the results of studying the chemical and mineral compositions of perovskite and ilmenite concentrates with the purpose to assess the possibility of their joint processing using carbothermic reduction melting. Emission spectrometry, X-ray diffraction, electron microscopy, and X-ray spectral microanalysis were applied in these studies. It was found that the basis of the ilmenite gravity concentrate sample is modified ilmenite represented by leucoxenization products – pseudorutile and rutile, with their total content in the concentrate to be about 80 wt. %. Composition of other minerals (alumochromite, chromite, magnetite) includes titanium in the form of impurities – 2 – 3 wt. %. In the perovskite flotation concentrate sample titanium is contained in perovskite and titanite making up the bulk of the ore minerals of the concentrate. As for rare and rare-earth elements contained in the ilmenite sample – monazite having up to 33 wt. % Ce, and zircon were found. Perovskite sample contains rare-earth elements (REE concentration in wt. %) in loparite-(Ce) (22.8), aluminocerite-(Ce) (46.2), anсylite-(Ce) (51.3), torite (22.3), as well as in the main mineral – perovskite (2.8). With the exception of perovskite and loparite-(Ce), other REE-containing minerals are rare, and their share in total does not exceed 1 wt. %

Equal-Channel Angular Pressing (ECAP) has become an effective technique of severe plastic deformation designed to produce ultrafine grain metals with improved mechanical properties, such as a good combination of strength and ductility. A  report on the effect of ECAP routes on the mechanical and microstructure of commercial 5052 aluminum alloy needs also to be included. This work has been undertaken, in order to obtain the results. In this work, several deformation routes were used to process the Al – Mg (5052) alloy, namely A, Ba, Bc and C. Deformation route A involved repeatedly pushing the sample into the ECAP die without rotation, route Ba was performed by rotating the sample through 90° in alternate directions between each pass, route Bc by rotating the sample 90° in the same sense between each pass and route C by rotating the sample 180° between passes. The addition of the pass number decreases the grain size of ECAP-processed samples when compared to the as-annealed sample. It also confirmed that the microstructure of the 8-pass samples shows a finer grain size than the as-annealed sample. Furthermore, the Bc route (samples rotated in the same sense by 90° between each pass) has been proven to be the most effective deformation route, in order to obtain equiaxed ultrafine grain structure when compared to other deformation routes. This phenomenon takes place due to the continuous deformation in all cubic planes. The restoration after the 4-pass number will lead to the rapid evolution of sub-grains to high-angle grain boundaries, forming equiaxed grains. The characterization of the hardness number also shows that the addition of the ECAP pass number increases the hardness number of 5052 aluminum alloy, where samples processed with the Bc route indicate the highest hardness number at 168.4 HB. Moreover, a similar phenomenon also suggests that the tensile strength of all ECAP deformation routes has comparable values. The effect of heat treatment for samples with the Bc route also shows that 200 °C annealed samples have the highest hardness number and tensile strength when compared to other samples.

Created in 2004, the high-entropy (HEA) five-component Cantor alloy CoCrFeNiMn is still in the focus of attention of researchers in the field of physical materials science due to a good combination of strength and plastic properties, which open up prospects for its use in various high-tech industries. We performed a brief review of recent publications by domestic and foreign researchers on improving the mechanical properties of the Cantor alloy by alloying with niobium and zirconium, which proved themselves well in alloying traditional alloys. Zirconium alloying leads to a lower melting point due to the formation of eutectic with all elements of the Cantor alloy. Alloying with niobium atoms in the range of 0 – 16 at. % ensures the formation of a volume fraction of the Laves phases and σ–phase up to 42 %, which, in turn, is responsible for a fivefold increase in the yield strength from 202 to 1010 MPa. The work on the joint alloying of the Cantor alloy with Zr + Ti + Y₂O₃, Nb + C, Nb + V systems was analyzed. With complex alloying, the mechanical properties are significantly improved. The paper reveals and discusses the physical mechanisms of hardening. Microalloying of 0.2 % Nb alloy with 1.3 % C provides an excellent combination of yield strength (~1096 MPa) and elongation (~12 %) after annealing at 700 °C.

The impact of hydrogen sulfide raw materials on steel equipment and pipelines is known and is associated not only with internal corrosion processes, but also with the hydrogenation of carbon and low-alloy steels used. Penetration of hydrogen into steel can lead to the loss of its strength properties and subsequent destruction of gas pipelines operated under high pressure conditions. The manifestations of cracking characteristic of hydrogen sulfide environments, which are a consequence of the penetration of hydrogen into steel, are the most dangerous from the point of view of the safety and reliability of the operation of facilities for the production and transportation of corrosive gas. The effect of H2S on the decrease in ductility of the main types of structural steels was studied based on the results of simulation tests. The formation of blisters (bloatings) and cracks on the surface of steels due to the effect of hydrogen on steel was recorded. The study of the phase composition and properties of corrosion products was carried out in order to assess their possible influence on the processes of steel hydrogenation. The formation of evenly distributed on the surface and the densest corrosion deposits will hinder both the corrosion processes and the penetration of hydrogen into steel. A decrease in the plastic properties of steel is also observed when exposed to hydrogen, which can be transported both separately and together with methane through the main gas pipelines. The main possible means of protecting steels that are unstable to hydrogenation is the use of corrosion inhibitors. It was established that the most effective corrosion inhibitors with rational technologies of application and dosage can protect steels from penetration of hydrogen into them and their destructive effect.

Currently, there is an active development and study of additive technologies. Metal 3D printing makes it possible to obtain parts and structures of complex configuration using a minimum of shaping operations, which can lead to a reduction in overall cost of the resulting products. In this paper, we studied the structure formation in manufacture of products made of stainless steels 10Cr12Ni10Ti (analogue of AISI 321) and 08Cr18Ni9 (analogue of AISI 304) by additive methods – SLM (Selective Laser Melting) and WAAM (Wire Arc Additive Manufacturing). In the course of microstructural analysis, it was found that during the manufacture of products using SLM technology, small austenitic grains oriented in the direction of heat removal are formed, and with WAAM method, austenite is formed mainly in form of dendrites. It is shown that porosity is formed during manufacture of the samples by SLM method, which is associated with non-melting of individual powder particles. When implementing additive manufacturing by WAAM (electric arc surfacing), there is no increased porosity. In the course of the study, a new defect of the structure formed during the manufacture of products by both methods was revealed – formation of interface boundaries between layers, which is associated with the technology of additive manufacturing itself. When manufacturing a WAAM product, it manifests itself more clearly than when obtaining metal by SLM. Boundaries of the surfacing rollers in the manufacture of products by SLM accumulate various intermetallides and structural defects more intensively, relative to WAAM. As a result of the small relative volume of one surfacing roller, compared with WAAM, accumulation of these defects and intermetallides can act as an effective barrier during movement of dislocations, which can lead to an increase in the strength properties of products.

To evaluate the phase and structural components of grinding media made of cast iron with a high content of copper and silicon obtained by extracting iron from copper-smelting slags, phase equilibria in the iron – carbon system were calculated with the addition of copper and silicon in various concentrations. The calculation was carried out using the ThermoCalc software package with construction of phase diagrams by the Calphad method. At the same time, temperatures of the beginning of phase transformations were estimated taking into account the presence of all thermodynamically possible phases in the system at various combinations of copper and silicon concentrations.

In 2020, EVRAZ United West Siberian Metallurgical Combine JSC (EVRAZ ZSMK JSC) completed work on the creation of a mathematical modeling system for all processing units of the metallurgical plant. During testing of the system, a high error was found in the existing factor model for predicting agglomerate production, which was developed taking into account the specific sintering rate of individual concentrates. The paper proposes the use of linear regression to predict the productivity of sintering machines, which, unlike nonlinear methods, is optimal for integration into high-performance optimization systems. A feature of the work is forecasting, taking into account the proportion of the agglomeration charge. The model was tested at EVRAZ ZSMK JSC and showed sufficient accuracy (R² > 90). A large economic effect is expected from the model. A separate study of existing agglomerate quality forecasting systems was conducted. Machine learning (ML) methods have recently made a great contribution to the development of forecasting models used to assess the quality of the agglomerate. This is due to the fact that the sintering process is a very complex dynamic with non‒linearity and a large delay. The physico-chemical phenomena involved in this process are complex and numerous. The neural network can constantly adjust the parameters of the model to reflect changes in systemic causes. A linear method was also studied to predict the agglomerate quality. Due to the poor quality of the resulting linear model, the “random forest” machine learning method was applied. Currently, the model is being operated as part of the integrated optimization program SMM Prognoz for the entire plant. For the convenience of the user, when implementing the module, visualization of the model quality using historical data was added, as well as the statistical metrics obtained.

The work is devoted to the study of the effect of microalloying with yttrium (Y) additives to improve the corrosion resistance of Incoloy 825 superalloy. The influence of Y on microstructure was evaluated by metallographic methods using optical and scanning electron microscopes, resistance to pitting and intergranular corrosion was evaluated by electrochemical and chemical methods of analysis. The paper describes changes in the structure, phase composition and hardness of cast samples with yttrium content of 0, 0.01, 0.05 and 0.1 wt. %. The obtained data correlate with the results of thermodynamic calculations of phase formation during crystallization. The influence of additions on the structure after strain hardening was investigated. Small addition (up to 0.01 wt. %) promotes increase of mobility of recrystallized grain boundaries. With increasing Y amount, the grain size decreases and hardness increases. It is shown that the greatest deoxidizing ability is observed at small additions of Y in the amount up to 0.01 wt. %, while the total amount of dissolved [O] decreased five times. Increasing the Y content reduces the ability to remove heavy inclusions from the melt, resulting in an increase in the proportion of oxide inclusions. The effect of additives on nitrogen [N] was not observed, and the volume fraction of nitride inclusions did not change, but the size of nitride inclusions decreased and the character of their distribution changed to uniform than in the alloy without Y. The results of pitting and intergranular fracture resistance tests showed that Y is an element that can be used to improve the corrosion properties of Incoloy 825 alloy. The best combination of resistance to the two types of corrosion was observed for the 0.01 wt. % Y sample.

The goals of the work were to search and systematize the speed limits of the steel strip during hot-dip galvanizing, associated with the threat of product defects. Since speed can be combined with many other factors, this paper provides an overview of the known causes of common defects. The causes were grouped taking into account the operations of individual sections of continuous hot-dip galvanizing units. To determine the circumstances in which defects occur, a method was used that involved step-by-step stratification of retrospective data and comparison of the distribution density of influencing factors for defective and non-defective products. The method was applied in the analysis of the data on defects at the MMK Metallurgy plant in Turkey, obtained in 2020–2021. Twenty-one types of acceptable and unacceptable defects that occur during galvanizing of DX51D steel were selected for analysis. Twenty-two technological parameters were taken as factors, including the strip speed. For each selected type of the defects, a set of influencing factors is determined, and for some types of defects, the alleged causes of their occurrence are indicated. It is shown that the relationship observed for many types of defects with the strip speed can actually be caused by other factors. We determined the types of defects, the probability of which increases with an increase in the speed or the level of its change. The paper proposes measures aimed at preventing the increase in the proportion of defective products along with the performance gain.

Screw piercing of a workpiece is a process with complex cyclical nature of metal flow in deformation center. Setting up the deformation tool and its calibration, as well as the accuracy of the workpiece feed and release of the hollow billet from deformation zone, have a significant impact on the quality of the hollow billet: dimensional accuracy and presence of defects on its inner and outer surface. In the paper, a technical solution was proposed to increase the stability of piercing a continuously cast workpiece on screw rolling mills. Implementation of the idea involves the use of an improved calibration of the piercing mill tool. For both in order to achieve the workpiece alignment and its stable feeding along rolling axis of the piercing mill, it was proposed to add a special thickening (hump) on the roll input cone and to change calibration of its input section on the ruler in order to meet the workpiece with the rolls earlier: before the initial capture of the workpiece by the rolls, that is, before deformation of metal of the continuously cast workpiece by the rolls. To check and correct the proposed solution, the tasks of FEM-modeling of screw piercing process with a modified design of the tapered roll and ruler were set and solved using the QForm 3D software package. Results of the finite element modeling (FEM) showed that the use of improved tool calibration makes it possible to improve the alignment of the workpiece and ensure its stable position along the rolling axis of the piercing mill, thereby reducing the runout of the workpiece in the deformation center and thereby reducing the force on the rolls from 8 to 5 MN. The results of measurements of the hollow billets’ geometric parameters obtained by FEM showed insignificant relative deviations that fit within the regulatory limits.

Organization of technological process and design of a furnace significantly affect the parameters of post-combustion, determining the need to develop a mathematical model of post-combustion zone. Modeling of gas dynamics, chemical reactions, convective diffusion and heat transfer in the gas phase above the melt was carried out in an experimental melter-gasifier furnace at three different values of mass flow rates and two positions of post-combustion tuyeres. Temperature distributions and off-gas components concentrations were obtained. It was found that at the lower position of the tuyere, post-combustion is carried out in the area of reflected jet, stagnant zones are formed around the tuyere and between the reflected jet and the melt surface, which decrease the post-combustion level. At the upper position of the tuyere, post-combustion occurs inside the primary jet, intensive mixing of all components of the furnace atmosphere occurs, post-combustion undergoes more completely, which leads to an increase in the off-gases temperature with an increase in uniformity of temperature fields and concentrations compared with the lower position of the tuyere. At the lower position of the tuyere, the flame zone turns out to be open, its shape significantly depends on the mass flow, and the flame zone volume increases with an increase in the mass flow. At the upper position of the tuyere, the flame zone is closed, with an increase in the mass flow, its shape does not change, but the flame zone volume decreases. For reduction processes in slag melt, the upper position of the tuyere is preferable, while for production of the producer gas at the furnace outlet, position of the tuyere closer to the melt surface is preferable.

Shewhart control charts (ShCCs) are a powerful and technically simple tool for process variability analysis. However, simultaneously, they cannot be fully algorithmized and require deep process knowledge together with additional data analysis. ShCCs are well known, though, and the number of papers is great, as well as standards on ShCCs work in most countries, there are some serious obstacles for their effective application which are not being discussed in either educational or scientific literature. Just these problems are being considered in this paper. We analyzed two sides of standard assumption about data normality. First, we discuss the widely-spread misconception that measurement data are always distribu­ted according Gauss law. Then, it is shown how the deviation from normality may impact the method of ShCCs’ constructing and interpreting. Using a specific process data, we debate on right and wrong ways to build ShCC. Further, the paper describes two new definitions of assignable causes of variation: not changing (I-type) and changing (X-type) the system. At the end, we discuss how the work with ShCCs should be organized effectively. It is outlined that creating and analyzing ShCCs is always a system question of interaction between the process and the person who tries to improve this process.