The method of profiling circular pipes is used in the lines of pipe-electric welding and profiling units in order to master the production of pipe products of non-circular cross-section from corrosion-resistant steel grades. Tubular products used in nuclear power generation facilities have higher requirements to mechanical properties and geometrical parameters. In particular, the most difficult aspect of manufacturing profile pipes-windings for turbo-generator stators with a rectangular cross-section is ensuring the flatness of flanges and achieving the radius of the outer corner rounding within a tolerance of ±0.10 mm relative to the nominal value. In order to successfully master the production of this type of product, a synthesis of the circular pipe profiling scheme was carried out. The authors developed the technology of profiling in drive rolls forming box gauges and in non-driven four-roll stands. Computer modeling of the profiling process was carried out in the Marc Mentat 2021 program. After experimental rolling, the profiles’ geometric parameters were analyzed using an optical microscope and special software. Acceptance tests were performed in accordance with the requirements to profile pipes for windings of turbogenerator stators.

Stiffness modulus is an important technical parameter of each four-high stand of continuous wide-strip hot rolling mill and characterizes the roll force that causes elastic deformation of all structural elements of the working stand in the assembly. Accuracy of deviations of longitudinal and widthwise profile of hot-rolled strips and quality of sheet products directly depends on reliability of determination of such parameter at the design stage of efficient technological rolling schedule. After review of classical methods for calculating elastic deformations of four-high stands based on the laws of the elasticity theory and modern publications, it was concluded that it is necessary to take into account the dynamic component when determining the stiffness modulus of the working stands of hot and cold rolling mills. Lack of record-keeping above the specified component entails significant errors in the alignment of the roll gaps at the stage of mill setting for rolling the strips of the required final thickness. In this work, we studied the stiffness modulus of the finishing stands of the operating continuous wide-strip mill, taking into account their constructional features in the production of hot-rolled strips of various sheet gauge of low-carbon steels, mainly intended for further cold rolling. When analyzing experimental data, reliable regression equations were obtained that allow taking into account the effect of the rolled strip width on the stiffness modulus of stands. The results of investigations are presented in graphical and tabular form, demonstrating the change in the stiffness modulus for different mill stands. The results allow us to design and make changes to the existing hot rolling modes in order to ensure the required accuracy of the longitudinal and widthwise profile of hot-rolled strips.

The work is devoted to the study of development regularities of plastic deformation and destruction of medium-alloy steel with a tempered martensite structure (0.34C–Cr–Ni–3Mo–V–Fe steel) under active tension. This steel is characterized by a multi-scale defect structure and contains cementite precipitates and special carbides. An experimental study of the evolution of defect and carbide subsystems during plastic deformation required the use of different methods: optical and electron (scanning and transmission) microscopy; X-ray structural analysis; measurements of quantitative characteristics of the microstructure and pattern of microcracks and their statistical processing. The research revealed that the places of significant localization of plastic deformation at the pre-destruction stage are the boundary areas of grains (former austenitic and real marten­sitic); all structural components of tempered martensite (plates, packets, blocks of laths, laths). A comparison of nature of the deformation relief and the fine structure formed before destruction with the pattern of fractures at various structural-scale levels indicates that the destruction of the steel under study, as well as the plastic deformation preceding it, bears the features of heredity of the original internal structure. Thus, the fracture of the studied steel has a multi-level nature, caused by: hierarchy of the initial internal microstructure; evolution of carbide phases; localization of plastic deformation developing at all stages of plastic deformation and, as a consequence, preparing the paths for microcracks propagation.

The combined effect of inclined electric fields and a transverse acoustic field on the Kelvin–Helmholtz instability of the interface of viscous electrically conductive liquids is studied using the example of air – water and argon – iron systems. An inclined electric field, regardless of the effect of sound vibrations, leads to the increased Kelvin–Helmholtz instability in the micrometer wavelength range. The most intense increase in the disturbances of the interface is observed at the angle of inclination of the electric field π/3. This opens up new opportunities for the development of technologies for accelerated cooling of rolled products and surfacing materials by regulating the drop transfer of material. The combined effect of acoustic and electric fields has an ambiguous effect on the Kelvin–Helmholtz instability. In the case of an air – water system, sound vibrations lead to suppression of the Kelvin–Helmholtz instability, while a tangential electric field with a strength of 3·10⁶ V/m enhances this effect, and a normal field, on the contrary, weakens it. For the argon – iron system, sound vibrations lead to the complete disappearance of the viscosity-conditioned maximum and to a significant decrease in the growth rate of disturbances at the interface, which corresponds to the first maximum. Application of a horizontal electric field with a strength of 3·10⁷ V/m significantly weakens the effect of suppressing the Kelvin–Helmholtz instability, while in a vertical field, on the contrary, increases it. It was established that the restoration of the first hydrodynamic maximum in a normal electric field is possible with a ratio of specific electrical conductivities σ greater than 0.012, regardless of the presence of a sound field. A change in the influence of the vertical electric field from a stabilizing to a destabilizing one is possible with a ratio of σ from 0.015 or more.

JSC EVRAZ United West Siberian Metallurgical Plant is the main manufacturer of rails in the Russian Federation. The work traces the evolution of the plant’s rail assortment over the past quarter century. A brief review of publications on modern concepts of the formation of structural and phase states of defective substructure and properties of volumetrically and differentially hardened pre-eutectoid, trans-eutectoid and bainite rails during production and subsequent long-term operation was performed. The service life of rails is determined by many factors: metal purity, structure, phase composition, operating conditions, heat treatment technology, etc. Special attention is paid to a new type of rail products – rails of the DT400IK category with increased wear resistance and contact endurance made of eutectoid steel, designed for use in difficult conditions. The paper considers the promising areas of rail assortment expansion.

Alloys of the Cu – Ni – Mn system are used in many areas, and for some applications (watchmaking, dentistry, precision mechanics) they must have high hardness. A state of high hardness can be achieved by two-stage heat treatment – quenching and subsequent aging. To obtain a good set of performance characteristics, decomposition of the solid solution must proceed through a continuous mechanism, which can be regulated by additional alloying (for example, chromium) and aging parameters. In this work, we studied the influence of quenching and aging modes on microhardness of 56DGNKh (Cu20Ni20Mn2Cr) alloy. It was shown that quenching from temperatures of 700 – 750 °С provides higher microhardness values ​​than quenching from 800 °С. By varying the temperature and duration of aging, it was found that the maximum microhardness is observed at aging temperatures of 475 – 500 °С. Metallographic analysis shows that in this case, the supersaturated solid solution of Mn, Ni and Cr in copper decomposes into a less supersaturated solid solution and the precipitation of MnNi intermetallic particles occurs according to a conti­nuous mechanism. The change in microhardness of 56DGNKh alloy depending on the aging time is multi-stage: its increase at short exposures is replaced by a subsequent decrease at increasing exposure with a clearly defined maximum or “plateau” between these two parts of the graph, and this type of dependence is observed at all aging temperatures. X-ray diffraction phase analysis shows that during the aging process, concentration of the solid solution decreases and MnNi particles are formed, the crystal lattice period of which differs from the period of the solid solution by 50 pm. The observed patterns of changes in hardness during the aging process are explained from the standpoint of the general theory of decomposition of supersaturated solid solutions. The maximum increase in microhardness (up to 450 kgf/mm² versus 130 – 160 kgf/mm² in the state after quenching) is achieved at a coherent or semi-coherent interface between MnNi particles and a Ni-based solid solution. This is observed after quenching from 750 °С and aging at 475 °С for 10 h.

The authors investigated the microstructure and mechanical properties of a model wall manufactured by arc wire 3D printing. 3D printing was performed using heat-resistant pearlitic steel wire in coldArc reduced heat input mode. Stationary thermal imager was employed to analyze the thermal cycles during layer deposition. Compressed air cooling to 200 °C was applied before each layer deposition to reduce heat accumulation. The high temperature gradients between the molten metal and the cooled layer resulted in areas with non-uniform structure, typical of welded joints after arc welding. Such areas with non-uniform structure were formed during the printing of each new layer and repeated throughout the wall height. It was observed that each solidified layer undergoes cyclic thermal effects during the deposition of subsequent ten layers. Intensive heating from deposition of two to three new layers leads to partial structural-phase transformations in the underlying layer. Deposition of the next 7 – 8 layers leads to heating similar to the “tempering” thermal operation. Microstructure analysis across different areas of the wall revealed acicular bainite with a small proportion of lath ferrite, bainitic ferrite, and martensitic-austenitic constituents. A slight increase in the width dimensions of acicular structure laths was observed with increasing wall height compared to the lower layers. The highest microhardness values were observed at the wall and substrate fusion zone (320 ± 7 kgf/mm²) due to rapid heat conduction and high cooling rates during the initial stages of printing. In the wall bulk, microhardness values ranged from 260 to 300 kgf/mm². The scatter of values and the periodic nature of the microhardness curve are associated with the formation of areas with non-uniform structure within each deposited layer of the wall. The wall material exhibits high strength characteristics (up to 800 MPa) and relative elongation (9 – 12 %).

The phase composition of VZhL14N-VI nickel superalloy was analyzed in a wide temperature range – from room temperature to 1600 °C by means of CALPHAD (CALculation of PHAse Diagrams) calculations. In light of the findings, the authors devised potential heat treatment modes for VZhL14N-VI superalloy. The impact of different heat treatment modes on the grain size, hardness, and electrical conductivity of VZhL14N-VI superalloy samples produced by ceramic mold casting was investigated, as well as the effect on the alloy of high-temperature annealing at 1070 – 1170 ℃ for 1 – 4 h. The alloy heat treatment resulted in a notable increase in grain size and a decrease in hardness. The influence of artificial aging temperature after high-temperature annealing and quenching on the hardness and electrical conductivity of the alloy in the range of 610 – 810 ℃ was studied. At 810 °C, the alloy exhibits the most pronounced aging effect, accompanied by a rapid increase in hardness, reaching approximately 370 HV. In contrast to the observed changes in hardness, the electrical conductivity of the alloy exhibited minimal variation during the aging process. The proposed heat treatment conditions diverge from those recommended by the OST 1 90126–85 Russian standard for this alloy. The developed heat treatment mode includes the alloy heat treatment at a temperature of 1170 ± 10 ℃ for 4 h, followed by air cooling and aging at a temperature of 810 ± 10 ℃ for 10 – 14 h, followed by air cooling. The proposed heat treatment mode is expected to result in an increase in hardness of VZhL14N-VI superalloy castings by 10 – 20 HV in comparison to the samples subjected to the standard heat treatment mode.

The authors used the technique of constructing the schemes of multicomponent diagrams (n > 3) in traditional coordinates “temperature – concentration”, the basis of which are n – angles with a divergent coordinate grid at n > 4, to construct the liquidus surface of the Fe – B – Mn – C – Cr five-component system. Choice of the system was determined by the need to harden the surfaces of parts made from a large number of low-alloy steels by boriding. The critical points of the liquidus surface were melting points of the alloy chemical elements, melting points of borides and melting temperatures of eutectics of the phase diagrams, which are the sides of a pentahedral prism. Individual experimental melting temperatures of the steels and calculated melting temperatures of new eutectics during the interaction of eutectics of double phase diagrams were also taken into account. The latter were determined according to the eutectic reaction rule, which provides for the use of only melting temperatures of the initial eutectics in the calculation. At the same time, phase composition of the multicomponent boride eutectics of the system was determined. The resulting liquidus surface shows the temperature at which crystallization begins and the phase composition of the layer during boriding of casting mold coa­tings for surface hardening of castings. The calculated melting temperatures of eutectics form the solidus surfaces of the system. In accordance with the concentration values ​​of the elements, especially boron, five solidus surfaces are formed in the system at 1571, 1451, 1394, 1105 and 978 °C. These melting temperatures of eutectics are the boundaries between the diffusion and diffusion-crystallization mechanisms of formation of boronized layer in solid and solidifying states of treated surfaces, therefore, they determine the mechanism of formation of boronized layer, their phase composition, structural morphology and properties.

The paper considers the historical development of scientific views on the structure of oxide and metal melts. The authors, using the research of the Ural Scientific School and their own works as examples, examine the evolution of approaches based on the polymer (ionic) theory of oxide melts and the cluster theory of liquid metals. The possibility of using a polymer model to determine the boundary of slag transition from a homogeneous state to a heterogeneous one and conditions for the formation of a homogeneous slag with maximum refining properties is shown. Al₂O₃ can exhibit both basic and acidic properties. It was found that with Al₂O₃ content of up to 16 % in oxide melts corresponding to the slags formed in ladle furnace unit, alumina exhibits basic properties, and when its content exceeds more than 16 %, it begins to exhibit acidic properties. Additional information on activities of the oxide melt components allows us to determine the parameters of the slag with the best properties for non-metallic inclusions absorption. Metal melt is characterized by a “critical” temperature at which the melt during heating transitions from hereditary cluster-type disequilibrium to a state of thermodynamic equilibrium, i.e., the melt “homogenizes”. Nonequilibrium melts temporarily retain elements of the structures of the initial phases. Overheating of the metal above the “critical” temperature during thermal-time treatment makes it possible to improve and stabilize the quality of products. Modification of the melt leads to a significant decrease in the amount of necessary overheating and acceleration of the homogeneous melt formation. Fundamental studies of the properties and structure of metal liquids showed the development of a new applied direction under the general name “thermal-time treatment”.

The great demand for products of the drawing industry causes the need to increase the productivity of existing equipment. There are two ways to solve this issue: creation of new designs of drawing equipment and search for hidden organizational reserves. Increasing productivity through organizational measures requires less time and material costs for implementation. The paper considers the possibility and prospects of multi-mill servicing. Normative models of drawing equipment operation for multi-mill servicing were developed. The prospects of using the developed models are shown on the example of the existing production. Analysis of the drawing equipment operation made it possible to justify the processing modes for multi-mill servicing and thereby increase productivity by 1.35 times and reduce the cost of finished products by 2 %.

Ferrous metallurgy is a colossal industry with a huge number of industrial facilities and equipment built for centuries. It accounts for approximately 8 % of current global anthropogenic emissions of CO₂ oxides. The future of decarbonization of these assets depends on investments by major market players in the development and implementation of breakthrough steel production technologies and operation of the carbon units market. With careful and responsible management of companies’ climate agenda, even against the backdrop of ever-growing demand for steel, metallurgy has every chance of reducing greenhouse gas emissions by 2.5 times in 25 years. At the same time, the implementation of industrial and environmental innovations at enterprises requires an integrated approach. As part of the research, we studied the regulatory documents of the Government of the Russian Federation regulating reduction of carbon intensity of products, growth of energy conservation and reduction of the impact on climate of the metallurgical industry. Criteria for sustainable (including green) development projects for steel producers were identified. The analysis of EVRAZ Group’s climate initiatives, carried out as part of the implementation of the company’s decarbonization strategy, was conducted. The identified climatic projects of the Russian industrialists were developed with the aim of producing and selling coal units. The formulated key directions of decarbonization of domestic ferrous metallurgy include operational methods for reducing direct and indirect greenhouse gas emissions, transition to environmentally friendly technologies, the use of low-carbon energy sources, introduction of closed crude cycles of ferrous metals, and optimization of the total carbon intensity of the asset portfolio. The implementation of environmental and climate projects will ensure the sustainable development of the metallurgical industry, optimize integrated efficiency indicators, and identify a niche in the competitive business environment.

The increase in consumption of high-quality steel dictates the need for more steel undergoing the vacuum process, since processing the steel melt under vacuum improves its properties by reducing gas and non-metallic inclusions in it. However, rising fuel prices and the desire to transition to carbon-free metallurgy require the industry to reduce energy intensity and, as a consequence, reduce energy consumption. This can be achieved by switching to continuous production, reducing the period of technological downtime of high-temperature equipment, the temperature of which must be maintained to increase the lining service life and improve the final product quality. But the transition to continuous steelmaking requires the development of a number of new technological units capable of functioning within the framework of the continuous steelmaking unit, including the extra-furnace processing unit for the melt. The propose of the work was development of a theoretical basis for extra-furnace processing unit of molten steel with a continuous degasser. A unit for extra-furnace processing of steel melt with a continuous U-shaped vacuum degasser is presented, which is part of a unit for continuous liquid-phase iron reduction with a capacity of 10 tons per hour for production of St3 steel. The authors studied the influence of residual pressure in a vacuum chamber on the rate of degassing and the time of a gas bubble ascent. Dimensions of the vacuum degasser were determined taking into account the productivity of the iron reduction unit. A multilayer lining was selected, and losses to the environment were assessed, taking into account convective and radiant heat transfer.