The main structural elements of melts of foundry aluminum‑copper‑silicon alloys are elementary nanocrystals of aluminum, copper, silicon and their free atoms. The main crystallizing phases of these alloys are microcrystals of α‑phases, silicon and θ‑phases. The process of their crystallization is nanostructural. First, structure‑forming nanocrystals are formed from elementary nanocrystals and free atoms. Then the centers of crystallization of microcrystals of phases are formed from them. From them, the structure‑forming nanocrystals of m free atoms of aluminum, copper, and silicon, microcrystals of α‑phases, silicon, and θ‑phases are formed. It is shown that the structural stability during remelting of cast aluminum‑copper‑silicon alloys is inversely proportional to the concentrations of adsorbed hydrogen and oxygen atoms.

The article presents data on the chemical composition of bentonite clays from various deposits in Uzbekistan. The feasibility of mixing bentonite clays from various deposits to obtain higher technological indicators is shown. It is proposed to conduct research to adapt bentonites to the conditions of their use in the foundry industry of Belarus.

The results of a study of the effect of modification with cobalt powder on the mechanical properties of high‑strength nodular cast iron and tin‑lead bronze are presented. It has been shown that when cobalt powder is introduced up to 0.1 %, it is evenly distributed in the metal matrix. Increasing the amount of the introduced additive revealed that cobalt is predominantly concentrated in the areas that crystallize last. The introduction of cobalt made it possible to increase the tensile strength of high‑strength cast iron and the relative elongation of bronze. The introduction of cobalt powder does not affect other mechanical properties.

A comparative analysis of investment casting processes was carried out based on two technological approaches: traditional and modified, based on the use of additive technologies. The advantages and disadvantages of different types of additive technologies used for direct and indirect manufacturing of investment patterns are considered. The features of producing wax and paraffin investment patterns using steel molds manufactured using the additive technology of sheet lamination are experimentally studied. The problems of implementing this technology related to the formation of a stepped relief of the surfaces of the mold cavity are discussed. An effective method for smoothing this relief by removing the recesses of the steps using putty is proposed.

The year 2024 marks a significant milestone in the history of OJSC “BSW – Management Company of Holding “BMC” as October 15th commemorates the 40th anniversary of the first steel melting and casting on a continuous casting machine in the electric steelmaking shop.

The purpose of this article is to provide a comprehensive modern perspective on the technical identity of the enterprise in honor of the 40th anniversary of OJSC “BSW – Management Company of Holding “BMC”. It unites past achievements, the present state, and a vision for mediumand long‑term development. Furthermore, it offers an overview of the establishment and development of Belarusian metallurgy from the 1970s to the 1980s.

This review aims to highlight the technical progression, intellectual and technical potential of the enterprise, which were shaped by 40 years of collective effort and international collaboration. The anniversary provides an opportunity to reflect on the origins, analyze achievements to date, and set benchmarks for sustainable mediumand long‑term growth.

This article holds unique value and novelty by consolidating diverse theoretical and historical materials on the 40‑year development of the enterprise. It describes the current state, strategic development directions, and includes excerpts from previous publications in scientific and technical journals, offering a theoretical foundation for practical application in engineering, professional, and educational activities.

This article presents the results of efforts to improve the technology for producing continuously cast billets measuring 300×400 mm, intended for manufacturing railway axles. The necessary technological operations, modes, and conditions required to meet the specified quality requirements for the macroand microstructure of continuously cast billets have been identified. A wide range of modern research methods was employed during the study, including various techniques for assessing the macrostructure of continuously cast billets, metallographic analyses using optical and electron microscopy.

This article examines the impact of dissolved hydrogen in steel on the formation of flakes. A method for measuring hydrogen content in liquid steel is described. Various approaches to hydrogen removal from liquid steel during both furnace melting and secondary steel processing are explored. Particular attention is paid to technological solutions aimed at minimizing hydrogen saturation during steel casting. The study provides a detailed account of implementing a working layer lining for intermediate ladles in continuous casting machines (CCMs) using dry masses.

One of the key quality indicators for coiled steel products, which is standardized and monitored during certification, is the depth of the decarburized layer on the surface. This layer forms during both rolling and heat treatment. Decarburization and scale formation significantly reduce the mechanical properties of the surface layers of steel products, making the surface more susceptible to scratches, scoring, and other defects during rolling, calibration, and cold heading. The formation of a decarburized layer necessitates additional machining costs, leading to increased metal waste and the disposal of a considerable amount of steel.

This article presents an experimental study aimed at identifying one of the causes of localized decarburization in 20G2R steel wire rod after annealing.

The influence of the deformation scheme under uniform and concentrated tension, compression and drawing on the intensity of strain hardening of low‑carbon steel with different dispersion of the structure is considered. With an increase in the grain size of ferrite, the tendency to hardening increases for all deformation schemes. Compression reduces the structural sensitivity of the intensity of strain hardening. Uniform tension enhances the intensity of hardening compared to drawing and concentrated tension, but is inferior to uniaxial compression. The breakthrough of dislocation accumulations through the subsurface layers of the wire of the stronger surface layer formed during drawing is accompanied by an increase in the density of mobile dislocations and a decrease in the intensity of strain hardening.

A rational set of mechanical properties and high hardenability of the diffusion layer ensure the use of sparingly alloyed steels for large‑module gears. The technology currently used by metallurgical plants for the production of hot‑rolled carburized steel does not ensure a stable production of a fine‑grained structure in products. The results of studies of rolled samples of sparingly alloyed structural steel 21KhGNMBA, heat‑treated according to different technological schemes are given. It has been established that at the same austenitic grain of the metal, rolled products from two suppliers differ significantly in the size of the actual grain. Coarse‑grained microstructure structure is explained by peculiarities of heat treatment of rolled products with long delayed cooling at incomplete annealing without recrystallization. It was obtained that the initial coarse‑grained structure of rolled products increased the tendency to grain aggregation of products during subsequent high‑temperature treatment, which led to an increase in the hardenability of steel and increased kinematic error of gears made of this rolled product.

A heat treatment process involving hardening with intermediate tempering has been developed to enhance the wear resistance of high‑precision die tools by 1.5–2 times compared to standard heat treatments. When heating for hardening above 1150 °C, secondary carbides dissolve intensively, austenite grain growth occurs, and there is a marked increase in retained austenite. The most suitable approach proved to be intermediate tempering at 600 °C, which avoids significant austenite grain growth with increasing initial hardening temperature, resulting in a fine to medium needle‑like martensitic structure with some residual austenite.

This study examines the artifacts introduced during metallographic sample preparation when using an angle grinder and plasma cutting for sectioning samples. The effects of heating and melting on the structural and phase composition of samples in the cut zone are discussed. The structures of steels that develop as a result of improper sectioning are also presented.

The influence of modes of preliminary heat treatment (HT) of P91 steel on crack formation during impact bending test has been investigated. Curves of dependence of force variation in time and specimen deflection variation depending on the force have been experimentally obtained, by which the following were determined: crack nucleation energy, crack development energy, maximum value of specimen deflection before fracture, maximum force and fracture force, strain rate, time before fracture, amount of fibrous component, impact toughness, stress intensity coefficient. The fractures were investigated by optical microscopy methods. It is shown that standard pre‑welding heat treatment (HT) of P91 steel – double normalization significantly reduces impact toughness, transforming the fracture into a quasi‑brittle state. The use of different variants of thermocyclic treatment (TCT) increases the total fracture energy and minimizes the amount of brittle component, while after TCT the fracture has mainly intracrystalline character.

The article presents sources of sulfur and phosphorus entering the weld pool, their influence on the quality of weld metal during electric arc welding and methods of their removal. It is shown that the influence of sulfur and phosphorus on the formation of hot cracks is mutually enhanced by the fact that the liquation sites of the compounds of these elements in the weld metal coincide. Sulfur removal is facilitated by Mn introduced into the weld pool melt and the main oxides of manganese and calcium contained in the slag, and phosphorus removal is facilitated by the main oxides of FeO and CaO contained in the slag.

The goal of this work is to develop a finite element model of a spherical graphite inclusion in ductile cast iron, modeling the process of its destruction under bilateral compression and verification of models by performing compression experiments.

A three‑dimensional model of a spherical graphite inclusion in ductile cast iron is developed and a finite element model that includes more than one million finite elements. It is constructed based on the assumption that in the center of the graphite inclusion there is a microscopic foreign spherical particle. According to one of the versions, it is a complex combination of oxides, sulfides and oxysulphides, the outer layer of this particle being coherent with the graphite lattice; according to another version, it is a particle of siliceous ferrite. This particle is framed by graphite, which has a polycrystalline sectoral structure in the form of pyramids with vertices diverging from the center of the particle; at the base of the pyramids are pentagons and hexagons. Each segment of the pyramid includes many graphite plates arranged parallel and layered on top of each other.

Numerical modeling of biaxial (quadrilateral) deformation of spherical graphite inclusion was carried out using the Ansys program. It is shown that the central particle is not deformed nor destroyed; the stresses in it do not exceed 53 MPa. It is demonstrated that destruction initially occurs along the boundaries of graphite pyramids, and at certain stages they are destroyed. In the longitudinal section, the displacement of the graphite planes inside the pyramids is also noticeable. The stresses in different parts of the pyramids differ by an order of magnitude and range from 14 MPa (mainly in the central part) to 192 MPa (at the edges of the graphite inclusion).

To verify the computer models, experiments were performed on the compression of ductile cast iron samples at a room temperature using a tensile testing machine. SEM studies have confirmed the sector‑pyramidal structure of a graphite inclusion with the presence of parallel planes inside the pyramids. It has been shown experimentally that, starting from a certain load, complete destruction of the pyramid‑shaped packets of graphite planes occurs. The results of modeling of quadrilateral compression adequately describe the behavior of a spherical graphite inclusion. In future, the obtained results will be used for comparison with the behavior of graphite at high‑temperature (900–1000 °C) deformation of cast iron.

The possibility of increasing the mechanical strength of porous materials from sponge titanium powders by two methods has been investigated. In the first case, sintering activation was carried out using alloying additives based on Al, ZnO and TiH₂. It was found that the maximum (1.8–1.9 times) increase in strength compared to samples made only from titanium powder is achieved by adding up to 0.5 % TiH₂. With the introduction of other alloying additives (Al, ZnO), the mechanical strength increases by no more than 16–20 %. The influence of sintering regimes and atmosphere on the mechanical strength of porous titanium has been studied. It is shown that samples sintered in a vacuum have 1.85–1.90 times higher mechanical strength compared to the same samples sintered in an argon atmosphere. In the second case, to increase the mechanical strength of porous titanium, it was proposed to use bidisperse mixtures consisting of fine and coarse titanium powders. For this purpose, up to 20 wt.% of a fine titanium powder with a particle size of 100–160, 40–100 or <40 μm was added to the titanium sponge powder with a particle size of 630–1000 μm. It was found that the introduction of 10–12 wt.% of the finest (<40 μm) titanium powder leads to a 4‑fold increase in the tensile strength of the porous material compared to porous materials made only from coarse (630–1000 μm) titanium powder of the same chemical composition.

This paper presents the results of a study on thermodiffusion zinc coatings obtained using a technology where zinc dust – waste from hot‑dip galvanizing created during the air blowing of pipes post‑galvanization – is used as the zinc component on steel products, including those with threaded surfaces. The technology involves applying zinc coatings to steel products, including threaded surfaces, through thermodiffusion saturation in a stationary container with a powder mixture consisting of 40 % Zn_waste, 59 % Al₂O₃, and 1 % NH₄Cl. This method yields coatings with good appearance, and the desired coating thickness, ensuring compatibility for threading, can be controlled by adjusting the exposure time.

The surface morphology and internal structure of graphite inclusions in ductile cast iron are investigated. Based on this, the theory of graphite nucleation on solid inclusions in the melt is confirmed. It is shown that the morphology of the outer surface of spherical graphite inclusions can vary from almost smooth to consisting of successively overlapping graphite flakes. It is suggested that, depending on the thermophysical conditions of crystallization, the growth of inclusions along one of the crystallographic planes prevails: [1010] for slow cooling (scaly surface morphology of the “cabbage head” type) and [0001] for faster cooling (smooth surface).

Metallographic studies of the internal structure of the spherical graphite inclusion has revealed its segmental‑layered structure with characteristic concentric wavy lines. Inside the inclusion, characteristic zones are distinguished: the center, sectors with characteristic junctions diverging from the center, and sometimes inclusions of siliceous ferrite are found. The polycrystalline structure of the inclusion with characteristic boundaries between graphite pyramids has been confirmed. The EPMA method revealed anomalies in the distribution of carbon, magnesium, silicon, sulfur, and oxygen concentrations in the graphite inclusion. In the center, content of the magnesium, sulfur, and oxygen is significantly increased. This confirms the theory of graphite nucleation on sulfides and oxides. In some cases, an increase in the oxygen content was observed on the outer part of the inclusion, which may be due to the displacement of oxides to the periphery during the growth of the graphite inclusion in the melt. The obtained results provide clarifi ations and supplementations to the theory of heterogeneous nucleation of spheroidal graphite particles in ductile cast iron, where the central part of the spheroid is a conglomeration of complex sulfides and oxides.

The article examines the impact of working conditions on employees in foundry production. The analysis of occupational diseases in foundries with different production profiles is presented. It is noted that the highest number of occupational diseases occurs in the cleaning and grinding, molding, and melting‑pouring sections of the foundry. The highest number of cases across various types of production is found among grinding operators, molders, furnace operators, pourers, and repair mechanics.

Currently, the processes of applying protective coatings to the surface of steel products are widely used – bronzing, latuning, etc. These operations are performed by thermocatalytically applying lead compounds to the surface of steel products, followed by reliable fixation of a layer of bronze, brass, etc. on this substrate. Taking into account subsequent technological operations, a significant amount of circulating, washing and wastewater containing a sufficiently large number of dissolved compounds is formed.