The paper presents the results of numerical simulation of the variable lateral reduction process of strips in a vertical stand of the roughing group of a wide-strip hot rolling mill. The simulation was performed with the aim of developing an engineering methodology for calculating reduction schedules to reduce the crop loss at the strip ends and increase the yield of sound metal. The simulation was carried out in the DEFORM-3D software package based on the finite element method for a slab with a cross-section of 1290×250 mm. The adequacy of the model was confirmed by comparing the width profile of the virtual transfer bar after stand No. 5 with industrial measurement data. Numerical simulation confirmed the effectiveness of the variable lateral reduction technology for minimizing geometric deviations on the end sections of the transfer bar in the roughing group of a wide-strip hot rolling mill. The best results were shown by the schedule with increased length and magnitude of the compensating vertical roll gap opening. During the rolling of strips from a slab with a cross-section of 1290×250 mm in stand No. 5 of a continuous wide-strip mill, rational parameters for variable lateral reduction were determined: an increase in the vertical roll gap by 15–20 % relative to the nominal value over extended sections at the beginning and end of the strip. The developed deformation schedule allows reducing the front-end narrowing to 7 mm and minimizing the formation of longitudinal protrusions (“ears”) on the rear end of the rolled product to 114.6 mm. Based on the identified patterns, practical recommendations are proposed for setting up variable reduction schedules to reduce the crop loss at the head and tail ends of the strip and increase the yield of sound metal. The obtained results provide a practical basis for the implementation of variable lateral reduction technology to improve production efficiency.

This article focuses on the numerical simulation of the cooling process of a pile of clad thick steel plates using the Finite Element Method (FEM). The main objective of the research is to predict the cooling time required for anti-flaking treatment and cooling of the stack to a temperature of 100 °C, after which sheet rolling can be unloaded from the slow cooling section. The relevance of the work stems from the fact that uneven cooling within the pile, caused by sheet flatness deviations, contact with the concrete floor, and other technological factors, directly affects the quality of the final product. During the study, a three-dimensional model based on the Finite Element Method was developed, which considers comprehensive heat transfer (conduction, convection, and radiation), variable thermophysical properties of the dissimilar layers of the bimetal (base layer K60 and cladding 08Kh18N10Т), as well as realistic production conditions: rolling rate, sequential pile formation, and surface roughness. The model was verified and adapted based on the results of a laboratory experiment, which allowed for refining the key heat transfer coefficients for steel-steel, steelconcrete, and steel-air contacts. As a result of simulating a series of industrial scenarios, analytical dependencies of the pile cooling time to 100 °C on the main technological parameters were obtained. It was established that the initial sheet temperature and the number of sheets in the pile (pile height) have the greatest influence, while the impact of the rolling rate is less significant. Based on the obtained data, empirical formulas describing these dependencies using power and logarithmic laws were derived. The practical significance of the work lies in providing a tool for the precise calculation of cooling process parameters, which enables process optimization, reduction of production time, and minimization of the risk of defects in clad steel plate.

The article presents a comprehensive study of the mechanisms of niobium carbonitride formation in steels and alloys for various applications. Based on thermodynamic analysis and experimental data, three main types of inclusions are characterized in detail: primary (blocky, formed in the liquid metal and at the beginning of crystallization), secondary (eutectic, forming within the liquidus-solidus range during the final stages of solidification), and tertiary (solid-phase, precipitating below the solidus temperature). It is shown that the morphology, size distribution, and phase composition of the carbonitrides are determined by the alloy’s chemical composition, modification technology, and crystallization conditions. It has been established that for structural steels, the optimal niobium content does not exceed 0.4-0.5 %, while large primary and secondary inclusions (>1 μm) have a negative impact on plastic and toughness properties. In contrast, in heat-resistant alloys, eutectic carbonitrides, whose sizes are comparable to the cast grain size, form a structure that effectively impedes grain boundary sliding during creep. The highest efficiency in restricting grain growth is demonstrated by nanometric tertiary carbonitrides, which form during the decomposition of supersaturated solid solutions. A critical parameter determining the influence of dispersed particles on the structure is the ratio of their sizes and interparticle spaces to the grain size, where meeting the condition 5dinc < dgrain ensures effective inhibition of boundary migration. The results of the work allow for the optimization of niobium alloying technologies for the targeted formation of the structure in accordance with the performance requirements for the steel or alloy.

The article studies the technology of intermittent warm pressing and the process of forming various materials obtained under certain conditions under temperature and pressure. In this method, the pressing time is divided into continuous and intermittent (pause) stages. This method is used in the processing of composite materials, polymers, and some metal alloys. Intermittent pressing increases product quality and reduces the risk of deformation. Intermittent warm pressing technology is considered one of the promising methods for reusing iron scrap, a common waste product in the metalworking industry. Through this technology, iron powder is compressed at high temperatures and under gradual pressure, forming a dense and mechanically stable shape. The principles, advantages, and application areas of this process are examined in the article.

The main task of machine building technology is to manufacture parts with the lowest labor costs, with the highest productivity and coefficient of metal use. A great future in metal processing belongs to combined processing methods and additive technologies. These are the most advanced and advanced methods of manufacturing parts, which provide a sharp increase in labor productivity, a significant reduction in technological waste of metal, a decrease in the complexity of processes and the cost of production. The article is devoted to the design and manufacture of a new import-replacement tool for processing gears using additive technology. Additive technologies, or 3D printing, are an innovative approach to the production of products, in particular processing tools. The fundamental difference between this technology and traditional methods is that the product is obtained by adding material to the base, and not removing material from the workpiece, as is the case with mechanical processing. In this case, the SLS (Selective Laser Sintering) method was used – an additive method for obtaining a model, sintered by a laser beam. Field experiments were conducted to confirm the suitability of the proposed manufacturing method for the type of tools in question. Analysis of the work results of the proposed design showed an increase in the accuracy of the processed products by 1-2 degrees according to GOST 1643-81 and a decrease in the roughness of the side surface of the teeth to 1.2 microns.The research was carried out with financial support within the framework of a grant from the Government of the Tula Region – DS/175/IMS/24/TO “Design of a special importreplacement tool for finishing cylindrical gears.”

The active development of Siberia, the Far East, and the Arctic shelf by mineral resource companies poses a number of challenges for specialists operating mining equipment. Downtime due to the failure of individual components and parts of mining equipment leads to significant losses. Therefore, ensuring the proper functioning of excavator teeth and bits is a pressing issue, especially for equipment operating in low-temperature environments. It is known that the heterogeneity of the microstructure of crowns and teeth determines their further performance. Despite the active implementation of modeling and forecasting of the formation of the cast structure in excavator bucket tooth castings, premature failure is still observed, especially during operation on hard rocks in low-temperature climates. The paper examines the influence of heattreatment on the structure and complex of properties of a material operating under wear conditions on soils of varying strength. It has been shown that only the use of complex heat treatment can ensure the performance of excavator teeth and crowns. The use of homogenization annealing before subsequent hardening and tempering reduces the negative impact of the hereditary interdendritic microstructure in the original state, ensuring the reliability of the working parts of excavators.This study was supported by grant No. 24–29–00713 from the Russian Science Foundation, https://rscf.ru/project/24-29-00713/.

Current trends in industrial and technological development dictate the need to create materials with unique and optimized properties for operation under high loads, aggressive environments and extreme temperatures. One of the most promising groups of such materials is powder materials, characterized by a high degree of control of structure and composition. They are used in various industries due to their high strength, lightness, resistance to wear and corrosion. However, the operational properties of powder materials are often limited by their initial characteristics. Various processing methods are widely used to enhance their functionality. A special place among them is occupied by chemical heat treatment (CTO), a technology that makes it possible to change the structure and composition of the surface of materials by saturating them with active elements under certain temperature and chemical conditions. CTO is used to improve the wear resistance, hardness, corrosion resistance and other properties of the surface layer, which is especially important for powder materials used in conditions of intense mechanical stress or aggressive environments. The technology makes it possible to create functional coatings and surface modifications, expanding the scope of application of powder materials in aviation, automotive, energy, medicine, oil and gas and other industries. The relevance of the research topic lies in the fact that, despite the widespread use of powder materials, their properties and behavior under the influence of various CTO modes have not been sufficiently studied. Existing research often focuses on traditional metals and alloys, while powder materials require a separate approach due to their microstructure, porosity, and sintering characteristics. The purpose of the work is to study the effect of various types of chemical and thermal treatment on the operational properties of powder materials.

The study is aimed at upgrading electric drives of low-speed process units in ferrous metallurgy, such as rotary kilns, converters, roasting and sintering machines. The overall objective of the study is to increase the efficiency and reliability of electric drives of the units. The objective is achieved by partially transferring the speed reduction function to a special electric motor, as well as by implementing the modular principle of constructing the electric motor. The applied task of the study is to develop an energy-efficient modular electric motor for the electric drive of the OK 306 roasting machine. The task is solved by model design and comparison of the parameters of alternative versions of the electric motor. The modular electric motor consists of several traction linear modules operating on a common secondary element. The design of the electric motor is described and the design data of the traction linear module are presented. Based on the design results, data on four versions of the traction linear module for a gearless and geared electric drive with different values of torque and speed are obtained and presented. The basic version of the design provides the efficiency of the electric drive up to 49 %, which is 1.7 times higher than the efficiency of the existing electric drive. The analysis and discussion of the technical data of the basic version of the electric motor is carried out. It is stated that the designed electric motor has high technical and energy indicators, allowing it to compete with the serial electric motor of the basic electric drive. The competitive advantage of the developed electric motor also lies in its reliability, inherent in the modular design principle in combination with high overload capacity. A comparative assessment showed that the implementation of the developed electric motor in the electric drive of the incineration machine gives a significant economic effect, estimated at 3.22 million rubles.The study was supported by the grant of the Russian Science Foundation No. 22-61-00096, https://rscf.ru/project/22-61-00096/.

The challenges of manual arc welding of austenitic high-nitrogen corrosion-resistant steels with a nitrogen content of up to 1% (wt.) are considered. Studies of the technological weldability of nitrogen-containing steels 04Kh20N6G11M2AFB and 05Kh16G11ASND developed in Russia have shown the possibility of obtaining high-quality defect-free corrosion-resistant steels with a very low level of magnetic permeability of welded joints during manual arc welding with coated domestic electrodes O3L-9A and foreign-made electrodes ESAB OK 69.25. A new electrode EA-868 OP for manual arc welding is proposed, providing the required level of quality and properties of welded joints. The metal of various zones of welded joints does not have ferromagnetic properties. Magnetic permeability does not exceed 1.002 Gs/Oe. When testing samples in a 3.5 % NaCl solution for 1,000 hours, it was found that the corrosion properties of welded joints correspond to the indicators typical of corrosion-resistant steels when used in sea water. Welding modes and recommendations for limiting weld heat input are given, when performing which all welded joints do not have pores. It was found that when welding in the weld metal, the nitrogen content decreases to 0.35–0.42 % (wt.), which leads to a decrease in their strength properties by 30–39 %, therefore, equal strength of welded joints can be achieved by a corresponding increase in the cross-section of the welds. The obtained results provide technologists with the opportunity to select the electrode brand among the studied welding materials depending on the design requirements (03L-9A, ESAB OK 69.25 and EA-868 OP) for manual arc welding of nitrogen-containing steels without restrictions on the thickness of the base metal and can be used to develop industrial welding technologies for corrosion-resistant parts and structures for critical purposes, which require low magnetization.

It was established that during solidification of 15Kh13N2 pre-peritectic martensitic steel, microalloyed to 0.04 % wt. Nb, carbide phases rich in niobium (from 54.2 to 79.4 % wt. Nb) with an average size from 0.2 to 4.2 μm are formed. It is shown that chromium, nickel, vanadium, titanium, silicon and manganese are directly liquated at the crystallization stage, enriching the interdendritic space and forming a solid solution with an increased content of carbide-forming elements. For cast metal after quenching with high tempering, it was determined that the average value of microhardness in the interdendritic space is 226 HV, and in the dendritic crystal zone - 146 HV. The revealed features of crystallization and the individual nature of the distribution of elements between the microliquation zones “dendritic crystal - interdendritic space” in the first approximation allowed for three-dimensional measurement to present the primary structure of 15Kh13N2 martensitic steel as a material in which more plastic dendritic crystals are separated from each other by a hard and brittle matrix. As a result, the banded structure of deformation (metallurgical heredity) recorded by metallographic analysis, consisting of zones that are practically incapable of homogenization, can be reflected in the instability of mechanical property values in the assessment of the quality of rolled products on a macro scale. At the same time, NbC-based carbide phases, detected in the in the eutectic zones last to harden, increase the likelihood of instability of the mechanical property values of rolled products. The selection of the optimal heat treatment mode was performed in laboratory conditions on a 25 mm diameter billet, which was tested in workshop conditions on a 190 mm diameter rolled product with quenching from a temperature of 990 °C and tempering at 710 °C of a 10 t charge. The resulting microstructure provided the required level of strength and resistance to brittle fracture at negative temperatures in rolled products due to the formation of a finely dispersed ferrite-carbide mixture with a certain directionality relative to the “former” martensite needles in each of the “dendritic crystal - interdendritic space” microliquation zones.