查看更多>>摘要：Abstract A new temperature-velocity mode for rolling long-length rails is considered. Rails less than 50 m long were rolled using linear rolling mills. The production of rails with a longer length requires the use of billets with a greater weight and equipment having a novel design. In the case of modern rail-beam rolling mills, the number of stands is increased and some of the stands are combined into a continuous group. Universal rolling stands began to be used not only as sizing stands. The rails with a length of 100 m are rolled based on large-weight billets using rolling mills with a continuous reversible group of universal stands. A significant billet length leads to the formation of so-called temperature wedge, i.e., to decreasing temperature throughout the rail length while rolling in the last stand of the rolling mill. The calculations have shown that decreasing temperature throughout the rail length can lead to an increase in the height of the rails. A similar problem should be noted in the production of thin sheet metal with the use of a continuous broadband hot rolling mill. The rolling of the rolled metal in the finishing group of stands with acceleration makes it possible to reduce the cooling time of the rear section of the rolled metal and to heat up the metal due to a more intense deformation. The value of acceleration should be chosen in such a way that at the output from the finishing group of stands, the temperature of the strip should be the same throughout the entire strip length. In this paper, it is proposed to perform rolling the rails with the use of acceleration in which the value should provide the same neck temperature throughout the rail length in the last stand of a rolling mill, as well as reduce the height difference along the rolled product length. The same height of the rails throughout the entire rail length should reduce the cost of grinding and accelerate the procedure of rail laying, thereby providing an increase in the consumer demand and in the competitiveness of the product.
查看更多>>摘要：Abstract The balanced development of the global community in the next decade implies the achievement of sustainable development goals by improving the efficiency of managing the resources in the economic, social and environmental spheres of human activity. The latter two are increasingly important as part of globalization processes, which inevitably affect the national economic, social and environmental agenda. The main measures of the state national policy of the Russian Federation are aimed at solving socioeconomic task to ensure that every person living in this country can use their right to a favorable environment. The timely solution of social and environmental wellbeing tasks as indicators of the population living standards is a priority task for the state bodies in the country’s regions in cooperation with top management teams of backbone urban companies that bear a major social and environmental burden. In the regions with metallurgical plants as dominant local companies, an increase in the resources management efficiency is especially significant. The pollution of atmospheric air and water, high levels of occupational morbidity and injuries caused by the wear of equipment and safety violations at production facilities, prevalence of mortality over births, intensive migratory outflow, depreciation of engineering infrastructure in the context of simultaneously growing industrial output reflect an unbalanced standing of metallurgical production regions and prevent their sustainable development. This study made it possible to develop a system of indicators for estimating the resource efficiency of metallurgical production. The system contemplates their grouping by development components. This allows managements teams to evaluate the contribution of each set of components to the resulting value, propose measures and benchmarks for optimizing the coefficients, identify business competitiveness improvement factors, determine investment targets, and also demonstrate to the global community the transformation of production and economic activities of the companies in line with the global resource saving and sustainability trends.
Babenko A. A.Smirnov L. A.Protopopov E. V.Upolovnikova A. G....
6页
查看更多>>摘要：Abstract This paper describes theoretical and experimental studies of the dependence of the viscosity, coefficient of sulfur and boron distribution between slag and metal, as well as wear degree of periclase-carbon refractories on the basicity and boron oxide content in the slag. It is shown that the formed slags have the values of basicity from 2.0 to 5.0 and rather a high liquid mobility. These slags are characterized by an equilibrium interfacial distribution coefficient of sulfur increased to 5–20, which provides an equilibrium sulfur content in the metal reduced to 0.001–0.005%. The results of fundamental studies of the physical-chemical properties of refining slags of the CaO–SiO2–B2O3–Al2O3–MgO system formed the basis for development of the composition of environmentally friendly fluorine-free ladle slags and technological methods for their formation in the ladle-furnace unit. The recommended composition of such low-viscosity slags, which allow deep desulfurization, direct steel microalloying with boron, and a low aggressive effect on the periclase-carbon refractories, ensures formation of slags with a basicity of 3.0–4.0 containing 1–4% B2O3, 15% Al2O3, and 8% MgO. The formation of environmentally friendly ladle slags of the recommended composition was carried out in a ladle-furnace by loading lime, boron-containing material—colemanite (Turkey) containing 39–41%?B2O3, 26–29% CaO, not more than 5% SiO2, and 3% MgO, and pyramidal aluminum into the steel-teeming ladle for slag deoxidation and boron recovery. Implementation of the developed technology for the formation of ladle slags with the recommended composition ensured production of economically alloyed low-carbon structural boron-containing steels with a low sulfur content, including for production of large-diameter pipes with high strength properties.
Pavlov A. V.Spirin N. A.Beginyuk V. A.Lavrov V. V....
7页
查看更多>>摘要：Abstract The paper presents a balance model of the blast-furnace process improved by the researchers from the Ural Federal University and Magnitogorsk Iron and Steel Works. It generally represents a system of deterministic dependencies characterizing the thermal, reduction, gas dynamics, blast, and slag modes of blast-furnace melting. The basic principle underlying the model is full-scale mathematical modeling. Indicators characterizing the process of the final slag for implementation of the normal slag mode of blast-furnace melting (the slag viscosity at temperatures ranging from 1350 to 1550°C, as well as the values of slag viscosity gradients) were proposed. The slag viscosity gradient along with the acceptable ranges of slag viscosity at different slag temperatures are used in modeling the slag mode as the limiting factors for the diagnosis of slag mode. Selection of the limit values of each of the ranges and the viscosity gradient is carried out by the expert evaluation method. The structure of the model for calculating the parameters of the final slag is considered. Using a mathematical model of the blast-furnace process, the analysis of the slag mode of blast-furnace melting was performed according to the actual indicators of their operation. It was established that desulfurizing ability of the slag is insufficiently used; as a result, the smelted cast iron has a down-graded quality in terms of both the sulfur and silicon content. Due to the changes in the slag mode characteristics, other conditions being equal, it is possible to get a positive effect on the gas permeability in the slag formation zone; the gas reducing ability and productivity of the blast furnace increase; the coke consumption decreases. The authors present the results of design calculations of the performance indicators of the furnaces of the Magnitogorsk Iron and Steel Works when changing the composition of loaded materials. Recommendations on the slag optimal basicity are given. Calculations showed that the optimal values of basicity of the final slag, which ensure its maximum liquid mobility, for the operating conditions of blast furnaces of the Magnitogorsk Iron and Steel Works are 1.04–1.05 for the CaO/SiO2 ratio and 1.30–1.32 for the (CaO + MgO)/SiO2 ratio.
Kozyrev N. A.Osetkovskii I. V.Usol’tsev A. A.Polevoi E. V....
5页
查看更多>>摘要：Abstract The composition of the non-metallic inclusions and microstricture of the electric arc coating using the flux-cored wire of Fe–C–Di–Mn–Cr–Ni–Mo system has been studied. The electric arc coating has been formed with the help of the ASAW-1250 automatic arc welding machine using the investigated flux-cored wire. To reduce the level of contamination of the deposited metal with non-metallic oxide inclusions, aluminum gas purification dust was introduced into the flux-cored wire (instead of amorphous carbon). The composition of the electric arc coating was determined by using the XRF-1800 spectrometer. The microstructure of the electric arc coating has been studied by optical microscopy. The phase and elemental composition have been studied using scanning electron microscopy at the MIRA 3 LMH instrument. The non-metallic inclusions in the electric arc coating consist of oxides of silicon, fluorine, calcium, aluminum, and magnesiums. The darker component in the inclusion, which looks like rectilinear crystals directed from the surface deep into the inclusion, has a similar phase composition. However, the content of chemical elements in it is somewhat different. A small dark component with a rounded shape (aluminum and magnesium oxides) is observed in the inclusion. Traces of sulfur are distinct along the contour of the globules. Metallographic analysis of the deposited surface has shown that the microstructure of the deposited layer is a coarse-needle martensite. Its structure is uniform and has a dendritic (columnar) structure characteristic for cast metal. The results of the performed investigations allow elaborating the measures to reduce the content of non-metallic inclusions containing elements of fluorine, sodium and aluminum, which, in turn, may adversely affect the physical and mechanical properties of the deposited layer, for example, by using refining additives to reduce the contamination of the deposited layer with non-metallic inclusions.
Kulakov S. M.Koinov R. S.Lyakhovets M. V.Taraborina E. N....
8页
查看更多>>摘要：Abstract The paper considers the vital problem of human-machine control of complex process units and complexes with a large variety of states, multidimensionality, variability, and uncertainty. In ferrous metallurgy, these units include coke batteries, blast furnaces, steelmaking outfits (arc furnaces, oxygen converters), foundry and rolling complexes, rolling mills, main shops and production facilities. It is shown that, in the context of the twenty-first century, the model approach to creating control systems for these objects does not exhibit sufficient efficacy. Alternative approaches based on case-based reasoning (CBR) are considered. In particular, they include the full-scale model of and the full-scale approach to developing support systems and management decision-making. The well-known full-scale model procedures for applying the best practices (methods of standard representative situations and exemplary process cycles) are presented. A new CBR method of automated selection and implementation of control actions with the involvement of process operators is proposed for process control systems. A modified CBR cycle of command selection and the corresponding flowchart of the software control system for a cyclic process unit are developed. The improved CBR-cycle includes several additional operations such as the correction of control decisions for selected cases; retrospective optimization of implemented control decisions; preservation of not only the best and optimized, but also erroneous decisions; case base updating; generation of solutions in unique or previously unreported situations. The structure of the case information model is formed by the example of the software control of steel melting at an oxygen converter shop. This structure includes the data on a specific situation in the control system, parameters of selected control actions, and steel melting results. An example of the control program formation for preparing and conducting the upcoming steel heat is developed on the basis of the data about a pre-selected melting case at a modern oxygen converter shop.
查看更多>>摘要：Abstract The quality maintenance of metal products provides for an accurate prediction of the warranty period for safe operation. One factor that affects the service life of a product made of steel, especially high–quality (special) steel, having high long–term strength is the guarantee for the absence of flakes in steel (cracks identified during the transverse macrosection inspection, gray spots identified during the longitudinal fracture inspection). The object of this paper is to develop an effective technology for inspecting the hydrogen mass fraction in liquid steel, as its presence is largely responsible for the formation of flakes in steel.
Netyaga A. V.Kuskov Yu. M.Biktagirov F. K.Ignatov A. P....
4页
查看更多>>摘要：Abstract The effect of slag pool rotation on the formation of the structure of high-speed steel hardfaced by a PR-10R6M5 grade steel powder (315–650 μm fraction) in a three-section current-supplying mold 180 mm in diameter has been studied. It is established that even a low rotation frequency of the slag pool (from 40 to 60 rpm) promotes obtaining approximately 2 times more dispersed structure as to compare to the structure obtained with no rotation of the pool. The macrohardness of steel hardfaced under the pool rotation is about 5 HRC units higher than with no rotation.
Morozov A. V.Lavrov V. A.Cheglov A. E.Degtev S. S....
7页
查看更多>>摘要：Abstract In the paper, we study the complex effect of the normalization annealing modes of hot-rolled steel on the texture of high-alloy electrical isotropic steel with a high aluminum content and metal microalloying with tin and antimony while developing a technology for the production of high-alloy (Si content is > 2.9%) cold-rolled electrical isotropic steel with a low level of specific magnetic losses (P1.5/50 ≤ 2.50 W/kg for strips with a nominal thickness of 0.50 mm and P1.5/50 ≤ 2.35 W/kg for strips with a nominal thickness of 0.35 mm). Alloying of steel with aluminum (Al > 1.0%) and tin (Sn > 0.025%) improves the texture of the finished steel, significantly reducing the level of specific magnetic losses. The effect of heat treatment modes of cold-rolled steel on the formation of the microstructure of the annealed metal and the adhesion of the electrical insulating coating is considered.
查看更多>>摘要：Abstract The results of industrial tests of ShKh15steel grinding balls with diameters of 25, 30, and 35 mm of 5th hardness group as per GOST (State Standard) 7524–2015 at AO Kharkiv Pilot Cement Plant during grinding of cement in the second chamber of a cement mill are presented. It is shown that the use of ShKh15 steel grinding balls with small diameters to grind cement ensures grinding fineness of 10–11% (residual for a sieve with a mesh no. 008) under their specific consumption of 1.136 kg/t of cement, which is a factor of 1.9?less than in using cast-iron cylpebs.
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