Based on thermodynamic calculations, it is shown that heating and cooling of metals and alloys are reversible, equilibrium processes. Based on thermodynamic calculations, it is shown that melting and crystallization of metals and alloys are also reversible, equilibrium processes. With an increase in the cooling rate of the metal, the temperature of its equilibrium crystallization decreases. At a high rate of metal cooling, a short‑term initial process of nonequilibrium crystallization is observed, which quickly passes into the main stage of equilibrium crystallization.

Options for improving the quality of castings during injection molding are considered. The variants of the design and placement of the chill vents in the mold are presented. The practical experience of using chill vents in order to improve the ventilation system of the mold to ensure a reduction in the defect of the gas sink molds and porosity is described.

The article demonstrates the increasing trend of implementing the CHM technology in Russian foundries, highlighting the advantages of this technology and the equipment utilized. An analysis of the current market situation for foundry equipment supply is conducted, along with examples of modern Russian equipment produced by Rodonit company (St. Petersburg).

A nanostructural mechanism of structural stability during remelting of foundry binary alloys has been developed. This mechanism is determined by the stability of the centers of crystallization of microcrystals of α‑phases and β‑phases. It is shown that this stability depends on the concentration of adsorbed hydrogen and oxygen atoms. The higher these concentrations, the less stable the centers of crystallization of α‑phase and β‑phase microcrystals in melts of foundry binary alloys, and vice versa. With an increase in overheating and (or) the holding time of melts of foundry binary alloys, the concentrations of adsorbed hydrogen and oxygen atoms in them increase. As a result, structural stability decreases during the remelting of foundry binary alloys.

The article compares the properties of kaolin and bentonite clays. It has been shown that kaolin clays have high fire resistance, and bentonites have high astringent properties. The experience of specialists from OJSC “MTW” in the joint use of various types of clays is considered. The combination of kaolin and bentonite in the suspension made it possible to increase the strength of the molding sand while maintaining moisture levels. The disadvantage of kaolin clay suspensions is that the moisture content increases with increasing dosage. When preparing bentonite suspensions, their short shelf life should be taken into account.

A nanostructural mechanism for recrystallization of binary aluminum and tin bronzes has been developed. First, structure-forming nanocrystals of α-phases, β-phases and γ-phases are formed from elementary nanocrystals of copper, aluminum, tin and their free atoms. The crystallization centers of microcrystals of phases are formed from them. From these centers, structure-forming nanocrystals of phases, free atoms of copper, aluminum, tin, microcrystals of α-phases, β-phases and γ-phases of binary aluminum and tin bronzes are formed.

The production of seamless hot‑deformed pipes from martensitic stainless steel with a high chromium content, used under the constant influence of aggressive environments, involves overcoming a series of technological challenges. These challenges are due to the metal’s structural features, such as relatively low plasticity, a narrow temperature range for hot deformation, a tendency to defect formation during rolling, and more intense wear on the rolling tools. The article discusses the main stages of research work on mastering the technology of producing seamless hot‑rolled pipes from stainless steel grade L80 type 13Cr at OJSC “BSW – Management Company of Holding “BMC”. It presents the results and complexities of mastering the technology for producing seamless stainless steel pipes, analyzes the results aimed at reducing the cost of finished products by increasing the durability of piercing mandrels, the resistance of disc saws for cutting blanks, eliminating metal adhesion to the piercing mill’s Dishar discs, increasing the productivity of the rolling line and heat treatment process.

This article presents the results of research on the processes occurring during the synthesis of wollastonite‑containing ceramics obtained from various clay components. The peculiarities of crystalline phase formation in the material are described. The obtained information lays the foundation for the organization of ceramic production that is in demand in the metallurgical industry.

The technology of manufacturing dies from a hard alloy granulated mixture includes the following operations: preparation of raw materials, forming of blanks, and subsequent sintering. The preparation of hard alloy mixtures consisting of carbide powders and binder metals is one of the main operations in the production of hard alloys. The properties of the resulting alloys largely depend on the conditions of performing this operation. All operations are interconnected, and any change in technological parameters can lead to a change in the formation of the final material structure and, consequently, its properties. This article discusses the technology of manufacturing and the production process of die blanks from a hard alloy granulated mixture. The results of laboratory studies of the hard alloy mixture, the manufacture, and production tests of die blanks are described.

During repeated drawing of low‑carbon steel, the initial grain size of ferrite and the intensity of hardening affect the accumulation of defects in the crystal structure and the overall decrease in the plastic properties of cold‑formed wire. Minimizing the cell sizes and reducing the intensity of deformation hardening for a more dispersed initial structure maintain an increased relative contraction of fine‑grained steel after large total compressions. The increase in the tendency to harden coarse‑grained steel is accompanied by an increased decrease in the ductility of the wire during repeated drawing. Large total compressions increase the structural sensitivity of the relative constriction of low‑carbon wire.

This work presents investigations on the structure, chemical analysis, and strength properties of deposited metal using two types of metal powder compositions, namely the primary powder and the residuals (secondary) of the heat‑resistant ironchromium‑nickel alloy Inconel 718.

Based on the obtained results, the causes of the formation of a fine‑cellular‑dendritic directional structure with needle and dendritic morphology were determined, as well as the decrease in heat resistance of the deposited material from the secondary powder of the heat‑resistant iron‑chromium‑nickel alloy Inconel 718 at elevated temperatures.

Foundry production is a versatile industry that allows the production of products of almost any configuration and geometric dimensions. These products can be made from materials based on various metals and alloys, bimetallics, and composite materials. The obtained products can have uniform or gradient properties. However, to obtain a product with significantly different properties on the surface and in the volume from the casting, it is expedient to apply coatings with desired properties on the castings that complement the properties, allowing the improvement of coating performance. The paper focuses on the production of cast composite materials with improved surface properties. Various types of coatings based on high‑entropy alloys, cermets, polymers, carbon nanotubes, capable of enhancing the properties of cast composite materials, are considered. The classification and peculiarities of applying these coatings on the surface of composite materials are presented. The prospects of using these coatings to improve the properties of cast composite materials are shown.

As a result of the study of flame‑induction heating of steel and cast iron shavings, optimal heating modes, dimensions of the furnace and the ratio of the sizes of its components (gas‑flame and induction heaters) were established, which served as the basis for the development of a new heating technology, which ensures minimization of dimensions in comparison with known analogues, increasing the productivity and efficiency of the furnace. It has been established that at the stage of evaporation and removal of water vapor and light oil fractions from the chips in the temperature range of 100–550 °C until the optimal oil concentration of 1.5–3.0 % is achieved, among all known methods of muffle heating, gas‑flame heating is the most economical and productive heating, and subsequently, when heating a dehydrated porous mass of metal with a density of 1100–1700 kg/m³ to 850 °C – induction heating in an atmosphere of products of thermal sublimation and destruction of coolant. It is advisable to carry out induction heating with a current frequency of 2.0–2.4 kHz with a ratio of the lengths of the gas‑flame and induction heating zones of 2.0–2.5 and the dimensions of the inductor (height to hole diameter) of 3.7–4.0. The degree of oxidation of hot‑pressed briquettes corresponds to the initial oxygen content in the chips: for steel – 1.3–1.7 %, for cast iron – 0.46–0.47 %. The data obtained made it possible to develop a technology for flame‑induction heating of ferrous metal shavings, as well as the design of a small‑sized furnace with a specific productivity of 6500–9500 kg/m²·h and an efficiency of 40–45 %.

A method for the formation of a composite material is demonstrated, which involves applying titanium to one side of the textile blend 07S11‑KV (produced by OJSC “Mogotex”) and carbon to the other side of the fabric. Tests were conducted on the obtained material in a climatic chamber at temperatures ranging from –20 °C to –40 °C. It is shown that the developed composite material withstands low temperatures well, with no additional deformation of the composite material or structural defects observed. This composite material can be considered as promising for special applications in low‑temperature conditions (antistatic, microwave absorbing, biomedical).

The analysis of the structure of ballistic materials was carried out and the optimal mechanical properties necessary to ensure the best bullet resistance and durability of armored steel were selected. A study of 45X2NMFBA armor steel was carried out under various heat treatment modes. The optimal modes of heat treatment have been determined to ensure an increase in mechanical properties. It was found that with an increase in the cooling rate of steel, a finer‑grained structure is formed, and an increase in the quenching temperature leads to an increase in the grain of primary austenite. The results of optical microscopy and mechanical properties of the studied steel samples are presented

Modern casting model kits, often created using adhesive technologies, can experience deformations leading to warping and even destruction. This can occur due to differences in thermal expansion and moisture absorption rates between the material and the adhesive. The study evaluated the behavior of the adhesive joint in model kit elements under operational conditions in liquid and humid environments, assessing the hardness and strength of the joint. The analysis revealed a correlation between the density of the plastic and the quality of the adhesive joint.

The knowledge about distribution of chemical elements in graphite is crucial for understanding the mechanism of nucleation and growth of graphite inclusions during high‑temperature crystallization of a cast iron melt. It is also important for understanding the mechanisms of subsequent plastic deformation of cast iron.

The specificity of the electron probe microanalysis (EPMA) of spherical graphite inclusions in cast iron, which is connected with a selection of the specimen’s cross‑section to be studied, is described. The most reliable and informative results are obtained when the graphite inclusion is cut by a plane of the metallographic section exactly in the middle.

Comparative EPMA is performed of the profiles of chemical elements over a cross‑section of graphite inclusions in the ascast and deformed (by hot extrusion) ductile iron. It is found that in the as‑cast state, the center of inclusions, in addition to the main element (carbon), features anomalies in the concentration profiles of a number of elements. Magnesium, silicon, sulfur, oxygen and sometimes iron exhibit increased content in the center. This can be attributed to the presence of oxide, sulfides and oxysulfide microparticles in the cast iron melt during crystallization (or inclusions of silicon‑containing ferrite) on which graphite inclusions subsequently grow.

In the deformed cast iron, anomalies in the concentration distribution of elements in the inclusions are largely eliminated and their distribution becomes more uniform. The higher the reduction ratio, the larger is the homogeneity of the chemical composition. To some extent, the heterogeneity of the composition distribution is still found in the longitudinal section at deformation with the reduction ratio of 60 %. For the reduction ratio of 80 %, in cross section the inclusion becomes almost completely homogeneous in chemical composition over the in cross section.

The results of studying the processes of laser deposition of aluminum and magnesium‑based alloys, the features of the structure of deposited layers using electron microscopy and X‑ray computed tomography data, measurements of microhardness after laser deposition of aluminum and magnesium alloys are presented. Modeling of the stress‑strain state of flat components during laser deposition of an aluminum‑magnesium alloy containing 0.6–0.95 % magnesium, 0.7–1.0 silicon, up to 0.3 titanium, up to 0.5 zinc, and up to 0.4 % manganese was performed. The nature of the distribution of deformations and stresses during the use of various technological schemes of laser deposition during surface treatment of aluminum‑magnesium alloys by laser deposition methods is established.

The quality of obtained castings directly depends on the model equipment and the materials used for its production. The properties of elements of model kits, made of plastic and joined using glue technology, are examined. The properties of these joints were evaluated through natural aging under atmospheric conditions. Works were carried out to analyze the influence of abrasive properties of the molding mixture and its components on the quality of glued model kits. Hardness and plasticity tests of the molding mixture were conducted using G. M. Orlov’s sample with both standard and plastic inserts, both integral and glued.

This paper presents the results of a study on the effect of pressure treatment (direct hot extrusion) on the structure of graphite inclusions and the metallic matrix of high‑strength austempered ductile iron. Comparative analysis of the cooling processes of the cast high‑strength ductile iron billet without deformation and after deformation was carried out using simulation modeling methods. The results of the study on the effect of hot deformation (up to 950–970 ℃) on the fracture structure and mechanical properties of austempered high‑strength ductile iron billets are presented.

Gas inclusions significantly influence the quality of solidifying melts. Dissolved gases in liquid metals, due to diffusion and chemical reactions, contribute to the formation and growth of new inclusions. The mathematical problem of the dynamic behavior of a spherical cavity is solved using the Navier‑Stokes equation, treating the melt as a viscous incompressible fluid. An expression for the change in radius of a spherical cavity under Newtonian behavior of the melts is obtained.

The results of the analysis of occupational injuries among workers in foundry workshops with different types of production are presented. It is shown that the highest number of accidents by location occurs in the fettling‑cleaning, molding, and meltingpouring areas of foundry workshops, and the most hazardous professions are those of fettler, molder, melter, pourer, and repair fitter. An analysis of the causes of injuries in foundry workshops showed that about 76 % of cases occur due to organizational reasons, about 16 % due to technical reasons, about 6 % due to sanitary‑hygienic reasons, and about 2 % due to psychophysiological reasons. The possibility of predicting injury rates among workers in foundry workshops is demonstrated.

Safe operation of enterprises in the metallurgical and foundry industries largely depends on ensuring fire safety. Therefore, at enterprises, the adaptation of fire safety norms is of great importance. Categorization of premises and buildings according to explosion and fire hazards is carried out. 

The article provides an example of calculating the categorization of a room where there is no release of radiant heat, sparks, and flames – a garage for storing vehicles. This facility can be located in the same room or building as foundry and metallurgical shops.

An analysis of the formation of organic solvent vapors, represented by white spirit, ketones, alcohols, benzene derivatives, 1,4‑dioxane, ethyl cellosolve, and paint aerosol, was conducted. The substances belong to the 3rd and 4th hazard classes. In the production process, the base paint Uno HD, Diamont R‑M BASF P+E paint, Standoflex 2k autolak topcoat, and Standox fine 1k‑body single‑component putty‑pore filler were used. The consumption of materials was 6.3, 2.7, 1.8, and 3.7 tons/year, respectively. In calculating the paint aerosol emissions, the efficiency of the treatment facilities was assumed to be 52 %. The environmental tax amounted to 2,619.93 rubles.

Based on thermodynamic calculations of the substantial Universe, it is shown that the cosmological theory of the Big Bang is erroneous. The thermodynamic ban on this theory makes the hypothesis of dark energy expanding the substantial Universe also erroneous. It is shown that the substantial Universe is a thermodynamically equilibrium system. Therefore, the substantial Universe cannot disintegrate, losing its structure, cannot shrink to a point, cannot disappear into a black hole. The equilibrium substantial Universe exists forever, preserving its enthalpy, entropy, mass and temperature. The main reason for the redshift of spectral lines of light from distant stars and galaxies is not the expansion of the substantial Universe, but its clouds of gas and dust, which reduce the energy of photons.