Showing papers in "Metallurgist in 2021"
TL;DR: In this article, a concept scheme of waste-free production is proposed, where the task of improving the efficiency of developing a mineral deposit is accomplished by rational, integrated use of the Earth.
Abstract: As the population grows, the need for mineral resources increases, resulting in an intensification of their extraction. This increases the amount of industrial waste and, thus, the human impact on the environment. Further accumulation and storage of industrial waste lead to irreversible changes in the ecosystem. The only correct vector of environmental protection is the utilization of industrial waste. Mining waste can be disposed by creating waste-free technologies that take into account the integrated development of deposits. The creation of an additional material resource base of a mining company by processing mineral waste will allow implementing the tasks of integrated development of deposits. The impact of mining and metallurgical works on the ecosystem of the region is assessed. Significant conceptual issues of application of industrial waste in the closed cycle of mining and metallurgical works are considered. It is confirmed that waste-free production is possible with a system approach to the integrated development of mineral resources. The impact of mining and metallurgical works on the environment is classified, with the physical and chemical principles of impact as the main classification feature. The ecological and economic efficiency of the use of industrial waste is assessed. A concept scheme of waste-free production is proposed, where the task of improving the efficiency of developing a mineral deposit is accomplished by rational, integrated use of mineral resources of the Earth.
30 citations
TL;DR: In this paper, the history of the development of aluminum-lithium alloys and their application is presented, along with a history of their application in aviation and space technology.
Abstract: New models of competitive aviation and space technology cannot be created without contemporary materials. The development of aluminum–lithium alloys was mainly determined by the fact that the addition of lithium to aluminum alloys decreases their density and increases the modulus of elasticity, thereby providing a significant structural weight reduction compared to traditional aluminum alloys. Along with a reduced density, aluminum–lithium alloys have high strength, good corrosion resistance, and good weldability; therefore, they represent a strategically crucial material for aviation and space technology products. This article presents the history of the development of aluminum–lithium alloys and their application.
17 citations
TL;DR: In this paper, a pilot installation for performing electric resistance annealing (ERA) was designed and implemented, where a system of electrically conductive rollers was used to supply electric current directly to the heating zone.
Abstract: A direct electric resistance heating has been shown to be a preferable method capable of directly achieving the specified properties of the wire during annealing, as well as enabling an improved controllability of the annealing process by utilizing process automation, and providing flexibility of the industrial systems. To estimate energy consumption, temperature fields were calculated during the drawing process under different heating conditions. In addition, temperature measurements were conducted and experimental data treatment was performed for an indirect heating using a continuous furnace and electric-current heating. It was shown that in the process of drawing with the use of a pulsed current, an electroplastic effect (EPE) is created in the deformation zone. The described mathematical model was used to obtain the temperature distribution in the heating zone of the wire exposed to a pulsed current, the nature of which causes the EPE occurrence. The EPE significantly reduces power consumption and operating voltage applied to the workpiece, while ensuring that the specified parameters of the wire are obtained when higher values of current are used. A pilot installation for performing electric resistance annealing (ERA) was designed and implemented. The main purpose of the implemented installation for annealing steel wire was to create a system of electrically conductive rollers used to supply electric current directly to the heating zone. Such system represents a robust stand-alone link in the wire heating process and allows for a trouble-free installation at any transporting section of the heated element (annealed material). The use of an automated control system with temperature and control current feedback for wire annealing ensures a stable operation of the entire system. The use of the experimental installation made it possible to achieve an 18% increase in the annealing rate for a 100 kg wire coil. An automated control system was used to control the drawing process and ensure uniform physical and mechanical properties of the resulting wire when using the electroplastic effect. As a result, the experimental data were obtained, the treatment of which made it possible to draw conclusions and make recommendations regarding a commercial implementation of such installations into the manufacturing process.
15 citations
TL;DR: In this paper, the effect of temperature and speed conditions in radial-shear rolling (RSR) of D16 alloy is analyzed, and the length and volume of the back-end defect are calculated for each of the temperature andspeed conditions.
Abstract: The effect of five cases of temperature-and-speed conditions in radial-shear rolling (RSR) of D16 alloy is analyzed. The temperature of the rod after each pass is obtained from the simulation results. With decrease in the heating temperature of the billet, the self-heating temperature of the rod during RSR increases. Depending on the selected temperature, rolling speed, reduction per pass, and rod dimensions, the temperature change relative to the initial heating can be more than 100°C. The length and volume of the back-end defect are calculated for each of the temperature-and-speed conditions. With increase in the elongation ratio, the length of the back-end defect increases, and its volume decreases. The smallest back-end defect is observed in rods produced gradually decreasing the rolling temperature in each pass (for a 6 m rod, the scrap losses are 2.2% of the volume of rolled metal). For one of the temperature-and-speed conditions, the specific deformation energy consumption that does not exceed 24–35% of the total energy consumption is obtained. The rods produced by RSR have better strength and plasticity (σB = 452–486 MPa, σy = 262–290 MPa, δ = 13.0–16.5%) than those required by the GOST 21488–97 State Standard.
8 citations
TL;DR: In this article, the possibility of forming a graded structure in steel bars using radial-shear rolling was studied and it was shown that an ultrafine-grained structure extends into the bar from its surface to a depth of at least a quarter of the bar radius.
Abstract: This work is devoted to studying the possibility of forming a graded structure in 08Kh18N10T stainless austenitic steel using radial-shear rolling. Experimental studies show that an ultrafine-grained structure extends into the bar from its surface to a depth of at least a quarter of the bar radius. A transition zone is located in the area between 0.5R and 0.25R of the bar cross section. Due to structural heterogeneity in the bar cross section there is an increase in microhardness by more than a factor of two from the initial value of 152 to 320HV in surface layers and a smooth drop by 10.2% in microhardness within the central area of a bar. This points to a graded nature of the structure formed in the bars of 08X18N10T steel after radial-shear rolling. A study of mechanical properties shows an increase in the tensile strength by about a factor of two to 938 MPa and a reduction in elongation to 24% in the peripheral zone and to 19% in the axial zone.
7 citations
TL;DR: In this article, the authors investigated the influence of the methods and procedures used for the regulation of the conditions of charge dosing and landing of electrodes on the electric mode of a two-electrode single-phase furnace used for smelting commercial silicon.
Abstract: On the basis of data on the distribution of electric power in the working space of a furnace, resistances of the zones of charge, arc, and melt, and the characteristics of displacements of electrodes obtained with the help of an automated system of monitoring of the electric parameters of the process, we estimate the efficiency of the electric mode of a two-electrode single-phase furnace used for smelting commercial silicon. The influence of the methods and procedures used for the regulation of the conditions of charge dosing and landing of electrodes on the electric mode is investigated. It is shown that the requirements of stabilization of the useful power and its rational distribution over the zones imposed on the regulation of the electric mode are not satisfied. The instability of the useful power of the furnace is caused by the application of the manual mode of control and the errors of measurements of currents in the electrodes caused by the incorrect calibration of the reference ammeter. The realization of the technological process under the conditions of high landing of electrodes does not correspond to the rational values of the energy efficiency of the furnace and is accompanied by significant losses of the arc power of the furnace and silicon in the form of silicon monoxide. The absence of data on the state of the working space of the furnace does not enable us to control the distribution of power over its main zones and to realize the possibility of full control over the process. We present examples that confirm the oscillating nature of the technological process and significant asymmetry of the useful power of separated electrodes. It is shown that numerous violations in the course of the analyzed process are caused by the use of irrational methods and procedures of regulation of the modes of charge dosing and landing of electrodes. In particular, the alternation of the modes of loading of the charge with excess and lack of carbon leads to significant fluctuations in the useful power of the furnace and the powers of the arcs. Moreover, the course of smelting can be described as a permanent transient process from one extremely inefficient state into another.
7 citations
TL;DR: In this article, the accumulated experience of testing of carbon steels and corrosion-resistant alloys in the presence of aggressive CO2, which leads to the development of dangerous local corrosion defects is analyzed.
Abstract: The current stage of development of promising gas and gas-condensate fields on the territory of Russia is realized at the extracting plants whose products contain carbon dioxide (CO2). The presence of carbon dioxide, in combination with moisture and other factors, stimulates the intense development of corrosion processes and requires careful and well-justified analysis of the corrosion activity of working media with subsequent choice of the engineering solutions ensuring the reliable safe operation of hydrocarbon-extracting plants. We analyze the accumulated experience of testing of carbon steels and corrosion-resistant alloys in the presence of aggressive CO2, which leads to the development of dangerous local corrosion defects. These defects are developed especially rapidly under the conditions of condensation of moisture, which is most intensely accumulated in the process of the gas extraction in the first sections of the pipeline for the highest temperature drops. The tests carried out at the Gazprom VNIIGAZ, LLC demonstrated that local defects may develop on carbon and low-alloy steels (such as 09G2S steel) under the operating conditions of extracting plants in the presence of CO2 and moisture condensation. Especially high corrosion resistance was exhibited only by the alloy whose chromium content is ≥ 13%.
6 citations
TL;DR: In this article, the authors studied the problem of cleaning conveyor belts from adhered finely divided materials in the process of operation of belt conveyors, where the material remaining on the belts causes numerous problems for the conveyor transport.
Abstract: We study an actual problem of cleaning of conveyor belts from adhered finely divided materials in the process of operation of belt conveyors. The material remaining on the belts causes numerous problems for the conveyor transport. In the course of time, adhered particles fall into the subconveyor space, thus violating the normal operation of the conveyor. This also leads to rapid failures of the roller supports, excessive abrasion of the working surface of the belt, and hence, to a more rapid wear of the conveyor belt. The procedure of cleaning of the belts enables one to remove the indicated problems. At present, there are various types of available cleaning units. Each of these units has its own advantages and disadvantages. In most cases, this complicates the choice of the required unit. We estimate the efficiency of application of a discrete double-row scraper cleaner of the conveyor belt. Its application increases the degree of cleaning without damaging the surface of the belt due to the presence of a counterbalance clamping attachment.
5 citations
TL;DR: In this paper, the authors describe the development of an automated system for controlling the technological process of obtaining a modifying concrete additive comprising spherical silicon dioxide nanostructures, as well as presenting the main process-specific parameters to be measured, adjusted, signaled, and / or blocked.
Abstract: In this study, the authors describe the development of an automated system for controlling the technological process of obtaining a modifying concrete additive comprising spherical silicon dioxide nanostructures. The paper describes the automation object, outlines system development aims, as well as presenting the main process-specific parameters to be measured, adjusted, signaled, and / or blocked. A list of automation equipment of the field, lower, and upper levels of the automated process control system (APCS) is provided. As well as input signal processing, the automatic polling of sensors and instruments is achieved by employing a distributed system based on Siemens equipment for the collection of data, which interact via Ethernet. The paper considers software requirements for the APCS operation and analyzes its reliability. The maximum safety level of the APCS is SIL 3; the average service life is stated to be 12 years. The developed automated control system for the technological process of obtaining the silica-based modifying additive permits the development of its structure, specifically an increase in the number of measurement points using a 10% input-output margin. In addition, software and data support of the APCS allows the system configuration to be modified, as well as enabling its expansion through an upgrade and the input of new tasks (sets of tasks and algorithms).
5 citations
TL;DR: In this article, a two-high screw piercing of steel 50 billets was performed at feed angles of 15 and 18 degrees, and the wound was stopped at 10-12 mm distance from the rear end of the billet.
Abstract: Two-high screw piercing of steel 50 billets was performed at feed angles of 15 and 18 degrees Piercing was stopped at 10–12 mm distance from the rear end of the billet Axial fracture was registered at 15 degrees feed angle in front of the mandrel nose, while no fracture was observed at 18 degrees feed angle Piercing for similar parameters was simulated using DEFORM finite element analysis software, and several criteria were used for fracture prediction Ayada criterion was ineffective, as evidenced by the comparison with experimental data The normalized Cockcroft–Latham criterion was effective for fracture prediction only in the axial zone Results of this study showed that the most effective technique for fracture prediction is the construction of a dependence of “accumulated strain–stiffness coefficient of tension” along the trajectory of the point movement
5 citations
TL;DR: In this paper, the angular thermal radiation coefficients and the efficiency of arcs for different distances from them to the walls of electric-arc furnaces of 0.5 to 120 t capacity are calculated.
Abstract: The angular thermal radiation coefficients and the efficiency of arcs for different distances from them to the walls of electric-arc furnaces of 0.5 to 120 t capacity are calculated. A relationship between the arc efficiency and the specific power consumption of the furnaces is established. The arc efficiency versus the depth of submersion of the arcs into the metal bath and slag in high- and low-capacity electric-arc furnaces is calculated and plotted.
TL;DR: In this paper, the effect of preliminary deformation of continuously cast billets made of chromium-containing grades of steel by radial-shear rolling (RDR) on the structure and properties of seamless pipes was analyzed.
Abstract: The paper analyzes the effect of preliminary deformation of continuously cast billets (CCB) made of chromium-containing grades of steel by radial-shear rolling (RDR) on the structure and properties of seamless pipes. A bar stock measuring 105 mm in diameter was obtained using an RDR mill at large feed angles (β = 21°). A comparative analysis of the microstructure of the initial CCB and hotrolled bars has shown that radial-shear rolling enables intensive refinement of the structure of continuously cast billets, and ensures a high-quality (70 to 90%) work-up of the cast structure at reduction ratios of 2.0 to 2.2. A pipe-rolling mill (PRM) installed at the Pervoural’sk New Pipe Plant JSC (PNPP JSC) was used to obtain seamless pipes from the deformed bars, and the mechanical properties of such pipes were studied. It was found that the pipes obtained from the experimental billets are fully compliant with the ISO 11960:2004 requirements for strength group J55 (σt > 517 MPa; σ0.2 > 379 MPa; δ > 16%). In addition, the level of plastic properties of the experimental pipes (based on present elongation δ5, %) exceeds the ISO 11960:2004 requirements by 1.6–1.8 times. To achieve a comparable level of properties using the existing technology, an additional heat treatment (HT) is required, which points to the potential advantages of using RDR pre-deformed billets to obtain seamless pipes with the required properties.
TL;DR: In this paper, the possibility of preparing complex vanadium-containing ferroalloys directly from vanadium slag and their application in steelmaking is considered in a review, where the physicochemical and thermophysical properties of complex alloys (melting temperature, density, heat capacity, thermal conductivity, melting time in liquid steel, changes in steel temperature during ferro-alloy introduction) are studied.
Abstract: The possibility of preparing complex vanadium-containing ferroalloys directly from vanadium slag and their application in steelmaking are considered in a review. Complex alloys make it possible to expand the ore base for ferroalloy production since it may involve poorer and more complex charge materials. Due to this it is possible to regulate parameters of the production process of their preparation more flexibly. Dependences of the physicochemical and thermophysical properties of complex ferroalloys (melting temperature, density, heat capacity, thermal conductivity, melting time in liquid steel, changes in steel temperature during ferroalloy introduction) on the concentration of vanadium, silicon, titanium and manganese in the ferroalloy are studied. The most favorable effect on properties of the ferroalloys studied appears to be an increase in silicon concentration, in view of which with complex vanadium ferroalloy it is useful to include an element such as silicon, and the vanadium-containing oxide component of the charge may be leaner with respect to the basic element content than commercial vanadium pentoxide. Use of vanadium converter slag makes it possible to exclude the vanadium pentoxide preparation stage from the production chain for processing vanadium. It is beneficial for production because vanadium pentoxide processing is characterized by a high level of environmental pollution and loss of vanadium (about 25%). Use of complex vanadium ferroalloys during steel treatment demonstrates the expediency of their use. Combined introduction of vanadium with silicon, calcium, and manganese into a steel melt makes it possible to create a favorable composition and shape for non-metallic inclusions. The main advantages of preparing and using complex vanadium ferroalloys are demonstrated.
TL;DR: In this paper, the relationship between the initial structural state of steel 1055 and the evolution of its microstructural and mechanical properties under the influence of equal-channel angular pressing (ECAP) in a stepped matrix was discussed.
Abstract: This work discusses the relationship between the initial structural state of steel 1055 and the evolution of its microstructural and mechanical properties under the influence of equal-channel angular pressing (ECAP) in a stepped matrix. Deformation was performed at a temperature of 400°С along the Bc route with the billet turning 90° around the longitudinal axis for six passes. It was shown that the effect of the initial structure (ferrite-pearlite, martensitic, troostite) on the structural state and mechanical properties of ultrafine-grained steels consists in the inheritance of the original grain structure and mechanical properties during ECAP. It was also revealed that after six ECAP passes, regardless of the initial structural state, a relatively homogeneous grain structure with a grain size of 0.7–1.2 μm is formed, providing high mechanical property values. The highest strength characteristics were obtained in samples with an initial martensitic structure. Thus, the ultimate tensile strength and conventional yield strength increased from 1510 to 1843 MPa (an absolute increase of 333 MPa) and from 1315 to 1691 MPa (an absolute increase of 376 MPa), respectively; the relative elongation decreased from 11 to 4%, while the relative narrowing decreased from 35 to 11%.
TL;DR: In this article, a new design of guide shoes containing a longitudinal groove on the working surface and the delivery of coolant directly in the process of rolling was proposed to increase the wear resistance and reduce the adhesion tendency of the metal to the surface.
Abstract: We consider the problem of wear resistance of guide shoes in the process of piercing in a screw rolling mill. To increase the wear resistance and reduce the adhesion tendency of the metal to the working surface, we propose a new design of guide shoes containing a longitudinal groove on the working surface and the delivery of coolant directly in the process of rolling. The experimental testing of the proposed new design of guide shoes was carried out in the course of rolling of the pipes 194.5 × 15.9 mm in size. After rolling, adhered metal was not detected on the contact surfaces. In order to estimate the deformation of the metal with the use of the new design of guide shoes, we simulated the process of piercing and performed the comparative analysis of the influence of guide shoes of new design upon the parameters of piercing (as compared with the influence of the traditionally applied shoes). It was shown that the deformed metal does not exhibit any tendency to flow into the zone of cooling channels. We also reveal an insignificant increase in the axial speed of piercing, which exerts a positive influence on the weakening of a trend to the formation of internal captivity due to the lower cyclicity of the process. The mean normal force acting upon the guide shoes and the area of contact with the metal decrease by about 20% due to the presence of the groove. As the temperature of the working surfaces of the guide shoes decreases, their wear resistance increases and the quality of the outer surface of the pipes improves.
TL;DR: In this article, an experimental study into the distribution of contact stresses along the length of a milling roll barrel and external longitudinal stresses measured by a magnetic anisotropy sensor (MAD) with an accuracy of ± 1 MPa over a width of 250 mm of a steel strip with a thickness of about 1 mm during cold rolling at the exit from a four-roller mill 205/360 × 500.
Abstract: The article presents the results of an experimental study into the distribution of contact stresses (pressures) along the length of a milling roll barrel and external longitudinal stresses measured by a magnetic anisotropy sensor (MAD) with an accuracy of ±1 MPa over a width of 250 mm of a steel (08kp) strip with a thickness of about 1 mm during cold rolling at the exit from a four-roller mill 205/360 × 500. A quantitative analysis shows the influence of longitudinal stresses in the outer parts of the steel strip on the metal pressure in the deformation zone. An equation is proposed for calculating the coefficient of the influence of unevenness and distribution of longitudinal stresses along the strip width at the exit from the mill on the pressure of the metal on the rolls. A computer-aided design (CAD) system was used to model and calculate the deformation and strength indicators of rolling thin strips, taking into account the influence of the characteristics of the rigid ends on the deformation zone. The graphs of the distribution of normal and tangential stresses along the length of the deformation zone are calculated depending on the longitudinal stresses. I. M. Pavlov’s theory about the significant influence of the external “hard” parts of the strip on the pressure of the metal on the rolls is empirically demonstrated. Based on the results of the experiments, an equation is proposed that takes into account the effect of the uneven longitudinal stresses in the outer parts and the stiffness of the strip on the pressure. The equation for determining the average metal pressure on the rolls is refined, taking into account the influence of the outer parts of the strip on the deformation zone during thin-sheet rolling.
TL;DR: In this paper, a simulated coarse-grained heat affected zone microstructure formation mechanism is established in high strength low alloy steels using electron backscatter diffraction (EBSD).
Abstract: A simulated coarse-grained heat affected zone microstructure formation mechanism is established in high strength low alloy steels using electron backscatter diffraction (EBSD). The governing effect of dispersion and ratios between different types of ferritic structural constituents on variation in impact strength is demonstrated. It is assumed from results of simulating a heat affected zone coarse-grained area that a reduction in welding energy input leads to a shift in ductile-brittle transition temperature towards a lower temperature.
TL;DR: In this paper, a technology of hardening of the working surfaces of the rollers of dies intended for the treatment of titanium alloys is proposed, where the detonation deposition of the WC-10Co-4Cr alloy with a thickness of 600 μm and subsequent fusion of this layer with the help of a laser make it possible to increase the hardness of working layer up to 1057 HV (> 67 HRC.
Abstract: We propose a technology of hardening of the working surfaces of the rollers of dies intended for the treatment of titanium alloys The detonation deposition of the WC–10Co–4Cr alloy with a thickness of 600 μm and subsequent fusion of this layer with the help of a laser make it possible to increase the hardness of the working layer up to 1057 HV (> 67 HRC) In this case, the wear resistance becomes more than seven times higher as compared with the case of traditional thermal treatment applied for Kh12MFsteel
TL;DR: In this article, thermal and thermogravimetric studies of lead sludge in the presence of and without oxidizing agents were performed to determine the thermally active part of the charge composition.
Abstract: Results are provided for thermal and thermogravimetric studies of lead sludge in the presence of and without oxidizing agents in order to determine the thermally active part of the charge composition. It is shown that during oxidation firing of lead sludge the process begins with charge dewatering and organic compound decomposition, and rare metal oxidation commences after complete destruction of organic compounds. Addition of sodium nitrate or calcium hypochlorite oxidizing agents provides complete oxidation of rhenium and osmium in the range of 400–650°C with the subsequent extraction of osmium into sublimate and concentration of rhenium in the form of perrhenate compounds in the ash. In this case decomposition of organic substances proceeds in parallel with oxidation reactions of rare metals without affecting their oxidation.
TL;DR: In this paper, it is shown that by selecting the temperature for the beginning of rolling in the finishing group of stands according to steel composition (microalloying system) it is possible to achieve a significant improvement in the homogeneity of the composition, structure, and set of rolled product properties.
Abstract: Redistribution of carbon and other elements, and formation of the structure, composition, and properties of low-carbon Nb, Nb–Ti, Nb–V, Nb–V–Mo and Ti–Mo microalloyed steels during hot rolling is studied using metal of five laboratory melts. It is established that by selecting the temperature for the beginning of rolling in the finishing group of stands according to steel composition (microalloying system) it is possible to achieve a significant improvement in the homogeneity of the composition, structure, and set of rolled product properties. Therefore, it is demonstrated by experiment that chemical and structural heterogeneity of metal formed in the billet casting stage may be largely eliminated during hot rolling on the basis of controlling carbide (carbonitride) precipitate formation.
TL;DR: In this paper, it is shown that the use of aluminum powder reduces the loss of alloying elements, increases the hardness of deposited coatings, and reduces the cost of plasma surfacing due to a reduction in argon consumption.
Abstract: This work reveals that addition of 4–6 wt.% of aluminum powder to the composition of a hard alloy powder provides surfacing of high-quality coatings without pores, cracks, and other defects. At the same time, aluminum is a strong deoxidizer and a nitride forming element, which permits use of nitrogen, compressed air, and hot hydrocarbons instead of argon as transporting gases. It is shown that the use of aluminum powder reduces the loss of alloying elements, increases the hardness of deposited coatings by 3–5 НRС, and also significantly reduces the cost of plasma surfacing due to a reduction in argon consumption.
TL;DR: In this article, the influence of finish rolling and accelerated cooling stages on structure and property formation for low-manganese steel under laboratory conditions is studied, and the range of rolling parameters providing an optimum combination of strength, toughness, and cold resistance is determined.
Abstract: The influence of finish rolling and accelerated cooling stages on structure and property formation for low-manganese steel under laboratory conditions is studied. Rolling ends at temperatures in both the γ-region and at various temperatures in the γ + α-region. Accelerated cooling completion temperature is varied in the range of 630–350°C. Comprehensive analysis of the microstructure, crystallographic texture, and fine structure parameters of laboratory rolled specimen is performed. Specific features of structure and property formation are studied and compared with known pipe steels. The range of rolling parameters providing an optimum combination of strength, toughness, and cold resistance is determined.
TL;DR: RyRybak, S. M. Gorbatyuk, K. S. Khairutdinov, Yu. Ch. Tyulyaeva, P. Makarov.
Abstract: To the article “Utilization of Mineral Waste: A Method for Expanding the Mineral Resource Base of a Mining and Smelting Company,” by J. Rybak, S. M. Gorbatyuk, K. Ch. Bujanovna-Syuryun, A. M. Khairutdinov, Yu. S. Tyulyaeva, and P. S. Makarov, Vol. 64, Nos. 9-10, pp. 851–861, January, 2021
TL;DR: In this article, the variation in the heat fluxes from the arcs with the wall height in 100-ton electric arc furnaces (EAF) for different arc lengths and slag layer thicknesses and constant arc power are calculated and analyzed.
Abstract: The variation in the heat fluxes from the arcs with the wall height in 100-ton electric arc furnaces (EAF) for different arc lengths and slag layer thicknesses and constant arc power are calculated and analyzed. As the depth of submersion of the arcs into the slag is increased from 70 to 300 mm, the maximum heat flux in the lower part of walls decreases by half. As the arc length is decreased by a factor of 1.5 while the arc power remains constant, the heat flux decreases by 10 to 30% and its distribution over the height and perimeter of the walls changes.
TL;DR: In this article, a methodology for creating and testing electromagnetic stirring systems for billet and bloom CCMs has been developed based on theoretical and experimental studies, physical modeling, and industrial tests of electromagnetic stirrers designed by the VNIIMETMASH Holding Company.
Abstract: During casting of steel, especially alloyed and high-carbon steel, in billet and bloom CCMs, segregation, shrinkage, and crystallization macrostructural defects may appear, and they cannot be completely eliminated even with rational design and process parameters. Various methods of physical action on crystallizing continuously cast ingots can be used to improve the quality of billets and rolled products. One of the most technologically advanced methods is electromagnetic stirring (EMS) of the liquid phase of crystallizing billets. The industrial CCMs currently operating in Russia and designed for the production of high-quality billets are mainly equipped with foreign-made EMS systems. Having a number of advantages, such as efficiency and commonality, such stirrers also have some disadvantages, including undismountable housing (cannot be repaired locally) and the need for several cooling circuits and boiler-type demineralized cooling water. Currently, the VNIIMETMASH Holding Company (Moscow) is the main developer and supplier of electromagnetic stirring systems for CCMs in Russia. Implementing an import-substitution program, the VNIIMETMASH has developed and put into operation mold EMSs (M-EMS), strand EMSs (S-EMS), and final EMSs (F-EMS) in billet and bloom CCMs, including horizontal ones. The stator poles are cooled with mold water in M-EMSs and with water for the process equipment in S-EMSs and F-EMSs. The coils are wo++und with a submersible double-insulated wire. A methodology for creating and testing EMS systems for billet and bloom CCMs has been developed based on theoretical and experimental studies, physical modeling, and industrial tests of electromagnetic stirrers designed by the VNIIMETMASH.
TL;DR: In this article, the authors consider actual problems of production, transportation, and storage of hydrogen and demonstrate the urgency and prospects of subsequent investigations and introduction of hydrogen-based technologies in powder metallurgy.
Abstract: We consider actual problems of production, transportation, and storage of hydrogen and demonstrate the urgency and prospects of subsequent investigations and introduction of hydrogen-based technologies in powder metallurgy. We present predictions of an international organization according to which commercial mass production of hydrogen is expected in the nearest future. This will make hydrogen less costly and more available for the extensive applications in various branches of science and industry. It is indicated that hydrogen is not only a promising alternative energy carrier but also an efficient reducer for numerous metals and alloys and an element applied in various technologies of powder metallurgy aimed at getting broad ranges of high-quality products. It is assumed that hydrogen can find extensive applications in industry in the future.
TL;DR: In this paper, the authors present comprehensive scientific and technological solutions related to the large-scale production of new-generation rolled steel in an integrated metallurgical plant, in the form of a high-duty steel plate, each geometric element of which exhibits a customerspecified complex of physical and mechanical properties.
Abstract: The paper presents comprehensive scientific and technological solutions related to the large-scale production of new-generation rolled steel in an integrated metallurgical plant. The new-generation rolled steel is in the form of a high-duty steel plate, each geometric element of which exhibits a customerspecified complex of physical and mechanical properties. In the linear sections, surface and volume elements are effectively used as geometric elements. The results of research projects aimed at enriching our scientific understanding of the phase and structural transformations in steels are presented. The capabilities of the enterprise production and quality management system employed by the Magnitogorsk Iron and Steel Company are described; this system ensured the transition of the enterprise toward digital, highly efficient technologies for producing metal products.
TL;DR: In this article, the authors present the dependences for the numerical analyses of the curvature of reverse bend and the adjustment gap for the RLM both with horizontal and inclined positions of the rollers.
Abstract: It is shown that there are two basic types of design of roller leveling machines (RLM) according to the principle of adjustment of the gap between the rollers, namely, with parallel and inclined arrangement of the rollers. We present the dependences for the numerical analyses of the curvature of reverse bend and the adjustment gap for the RLM both with horizontal and inclined positions of the rollers. It is demonstrated that, in the case of straightening performed in an RLM with horizontal arrangement of the rollers, the gap decreases from 38.8 to 7.8 mm as the thickness of the sheet made of 10KhSND steel decreases from 40 to 12 mm. For the sheet made of 10G2S1D steel, it decreases from 38.6 to 7.2 mm and for the sheet made of 14Kh2GMR steel from 38.6 to 6.2 mm. In the case of straightening carried out in an RLM with inclined arrangement of the rollers for a sheet made of 10KhSND steel with a thickness of 20 mm, the minimal gap constitutes Cmin = 19.6 mm, while the maximal gap Cmax = 20.0 mm. Moreover, for 10G2S1D steel, we get Cmin = 19.5 mm and Cmax = 20.0 mm. Finally, for 12G2MFT steel, we find Cmin = 19.3 mm and Cmax = 19.9 mm. We performed the experimental straightening of sheets of 10 steel 16 mm in thickness and 2400 mm in width on a seven-roller RLM (produced by Severstal’). The comparison of the experimental value of gap Cexp = 13.1 with its theoretical value Ccalc = 12.8 mm shows that difference between these values is equal to 4.5%.