bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure of impurity phase inclusions in gray cast iron and their composition
Authors: Boldyrev D A , Amirov R N , Nefed’ev S P
Published: November 2020

It is quite difficult to control the content of carbide-forming elements in the production of casting ‘pressure plate’ of gray pearlitic iron grade SCh25 (GOST 1412–85). Therefore, it is necessary to conduct research and analysis of foreign inclusions, the basis of which are ‘uncontrolled’ carbide formers. The analysis of the content of ‘uncontrolled’ carbide-forming elements on the formation of zones with an interdendritic distribution of graphite types D, E (ASTM A247) castings of a pressure plate is carried out. The elemental composition of impurity inclusions is determined. It has been established that ‘uncontrolled’ carbide-forming elements are represented in cast iron in complex carbide-nitride and sulfide-phosphide phases. A conclusion is drawn on the effect of carbide formers on the formation of areas with an interdendritic distribution of graphite. All types of these phases are concentrated to a greater extent within the zones of interdendritic distributions of lamellar graphite D and E. This indirectly confirms the influence of ‘uncontrolled’ carbide-forming elements on their formation.
Influence of blast furnace slag type on physical and mechanical properties of Portland cement
Authors: Kapustin F L , Balueva T S
Published: November 2020

Physical properties, grain, chemical and mineral compositions of blast-furnace slags selected from the dumps of JSC ‘EVRAZ Nizhny Tagil metallurgical plant’ and PJSC ‘Nadezhdinski Metallurgical Plant’ were studied. Also, the same parameters of granulated blast-furnace slag of JSC ‘Mechel-Materialy’ currently used by cement plants in the Ural region as a mineral additive during Portland cement grinding were investigated. By chemical composition all of them are acidic. In contrast to granulated slag which mainly contains the vitreous phase dump slags are well crystallized and mainly contain the minerals okermanite, mervinite and monticellite. Dump slags have a Student’s t-criterion of more than 15.0, i.e. they can be used as a mineral additive during Portland cement grinding. The introduction of 20 % of the studied slags reduces the water demand of Portland cement of joint grinding and accelerates the setting of the cement paste, reduces the bending and compression strength compared to the additive-free cement. Slag-containing cements after 7 and 28 days of hardening have similar values of compressive strength: 27.2–29.2 and 41.1–43.0 MPa respectively, they are normally hardening and have a strength class of 42.5. Chemical, physical and mechanical properties of these cements meet the requirements of Russian Standard 31108–2016.
Research on the influence of the strip tension on contact stress and cold rolling force with a strain-hardening
Authors: Ilin K , Baranov G
Published: November 2020

The influence of strip tension on contact stress and cold rolling force with strain-hardening has been investigated by using a numerical method. Dependences between roll pressure and strip tension for one rolling case have been studied. A comparison of the results provided by an introduced method to the already known methods allowed measurements of inaccuracy when the arc of contact has been replaced by chord and whenthe yield strength value for each step has been replaced by the average value of yield strength. Approaching to the real shape of the deformation zone and step-by-step calculations of strain-hardening increases magnitudes of average normal stress and rolling force. The highest difference between obtained results in comparison with the introduced method and already known methods reaches the largest value in the case with intensely hardening steels without strip tension. The increase of strip tension shows less difference between methods. The introduced method lets to calculate the rolling force for different metals depending on strip tension with more precision. Obtained results of the numerical analysis of the influence strip tension on the average normal stress and rolling force were summarized in the form of functions convenient for engineering calculations, with inaccuracy less than 5%.
The use of technogenic raw materials to produce a high-alumina chamotte
Authors: Getman A A , Pavlova I A , Farafontova E P
Published: November 2020

When fused corundum is crushed, a finely dispersed powder is formed with an Al2O3 content of 93–95%, in the form of substandard material. It is advantageous to utilize this powder to obtain high-alumina chamotte with Al2O3 content of more than 62%. High-alumina aggregate (chamotte) was obtained by semi-dry technology with intermediate briquette molding from a mixture of corundum dispersed powder and enriched kaolin. Based on a final Al2O3 content of 65 wt. % the batch composition of the mass to produce a high alumina aggregate (chamotte) was calculated. From a mixture of dispersed corundum powder and kaolin moistened with a 5–7% technical lignosulfonate solution with a density of 1050 kg·m−3, a briquette was formed at a specific pressing pressure of 15–20 MPa. The briquette was fired at a temperature of 1700°C. The fired briquette had a strength of 164 to 193 MPa. The water absorption of briquettes was 11–12%. The phase composition of the briquette is represented mainly by corundum and mullite. The enriched kaolin did not show sintering effect on fine corundum.
Nanofine spatial dissipative structures with azimutal lattice curvation
Authors: Malkov V B , Chemezov O V , Pushin V G , Malkov A V , Shulgin B V , Malkov O V
Published: November 2020

The nanofine spatial dissipative structures (NSDS) were characterized by transmission electron microscopy and electron diffraction. The NSDS obtained by thermogradiently processing an amorphous selenium film by unilateral heating of its lower surface at T = 413 K preliminarily. The results indicate that the NSDS of hexagonal selenium obtained in an amorphous film possess an azimuthal curvature of the lattice and a nonlinear fan-shaped system of flexural contours on their electron microscopic image. The lattice of the above NSDS undergoes elastic – plastic rotational curvature around three mutually perpendicular directions. The lattice rotation angles of hexagonal selenium NSDS reach: around [001], – 25°, around the direction perpendicular [001] and lying in the plane of the amorphous film – 32°, around the direction perpendicular to the first two ones and not lying in the plane of the amorphous film - azimuthal curvature of the lattice, – 35°. Thus, as a result of electron-microscopic and microdiffraction studies, it was found that NSDS of hexagonal selenium with azimuthal curvature of the lattice, causing the curvature of its habitus, are in a nonequilibrium state.
Phenomenon of relaxation of inhomogeneous elastic rotational curvature of the lattice of nanofine spatial dissipative structures of hexagonal selenium
Authors: Malkov V B , Chemezov O V , Pushin V G , Malkov A V , Shulgin B V , Malkov O V
Published: November 2020

Nanofine rhomboid spatial dissipative structures (NRSDS) of hexagonal selenium were found and studied by means of transmission electron microscopy in amorphous Se films coated with nanofine layers of amorphous carbon, at a temperature of their thermo gradient treatment of 423 K. As a result, pictures were received of fan-shaped linear bending extinction contours on the electron-microscopic images of NRSDS. It was shown that in the above NRSDS take place continuous linear increase in the bend radius of the lattice along [001], due to continuous linear relaxation of the inhomogeneous elastic torsion of the lattice around [001]. The continuous linear relaxation of the elastic rotational curvature of the lattice around [001] in NRSDS of hexagonal selenium with inhomogeneous elastic rotational curvature of the lattice covers the entire nanofine rhomboid spatial dissipative structures, and not its part, as is the case with the formation of interblock boundaries in the nanofine rhomboid spatial dissipative structures.
Thermal stability of hafnium bronze subjected to dynamic channel angular pressing
Authors: Stolbovsky A , Popov V , Popova E , Falahutdinov R , Murzinova S , Shorokhov E
Published: November 2020

Thermal stability of the structure of Cu-0.8%Hf alloy subjected to severe plastic deformation by 2 passes of dynamic channel angular pressing (DCAP) has been investigated. It is demonstrated that after such deformation the microstructure of the hafnium bronze is non-uniform, where areas of cell structure are neighboring with thin-lamellar structure of twinning type. Such structure indicates the action of two deformation mechanisms, dislocation sliding and twinning. It has been revealed that doping with hafnium has considerably affected susceptibility of copper to relaxation processes under the DCAP and following annealing. It has been found that the microstructure formed under the deformation can be retained at the annealing up to 500°C without noticeable changes, and the microhardness changes only slightly in this temperature range. At the same time, at heating up to 600°C and higher the relaxation processes are developed in the structure which is accompanied with a drastic drop of microhardness.
Physico-mechanical properties of the sinter of various chemical composition
Authors: Sibagatullin S K , Kharchenko A S , Sysoev V I , Gushin D N
Published: November 2020

The paper includes data on the physico-mechanical properties of sinter of various origins including density (bulk, average, and true), porosity (open and total), critical angle of repose, internal and external angles of repose measured on dropping the material down onto a horizontal surface from a steel sheet inclined by 40°, 60°, and 80° to the horizon, angle of external friction on the steel surface, the strength properties of the sinter in a cold state and after reduction at a temperature of 500 °C. The investigated sinter had the following characteristics: an average density of 3.20–3.30 g/cm3; a true density of 4.43–4.57 g/cm3; an external angle of repose of 20.5–32.3 deg; a bulk porosity of 0.46–0.50 m3/m3; a degree of reduction by hydrogen at 500 °C of 3.3–4.8%. It demonstrated the following strength characteristics in the cold state: IR+5 = 92.0%, D0.5-5 = 5.5%, A-0.5 = 2.5%. The strength characteristics after low-temperature reduction in hydrogen atmosphere were as follows: IR+5 = 29.80 %; D0.5-5 = 57.6 %; A-0.5 = 12.6 %.
The effect of wear-resistant coatings composition based on niobium nitride on the structural parameters, mechanical properties and efficiency of the cutting tool
Authors: Tabakov V P , Khudobin L V , Chikhranov A V , Dolzhenko Y A
Published: November 2020

Single-layer wear-resistant coatings based on niobium nitride deposited on a carbide cutting tool are considered in this article. The influence of one and two alloying elements on the change of the coating structure, mechanical properties and efficiency of the cutting tool was studied. It was revealed that in all cases, alloying with titanium, zirconium, aluminum and chromium leads to a change in the microstructure and an increase in the mechanical properties of the coatings and the inclusion of two elements into the composition of coatings increases mechanical properties to a greater extent. Research has shown that cutting tools with coatings based on niobium nitride are characterized by a decrease in the stress state of the tool base and an increase in the total compressive stresses in the coating. Compared to titanium nitride, the niobium nitride coating reduces the temperature on the front surface of the cutting tool, but for complex-alloy coatings, there is a slight increase in contact temperatures. Changing the heat-stressed state and increasing the mechanical properties leads to an increase in the crack resistance of such coatings. It is shown that the use of developed compositions of multi-element coatings can improve the efficiency of the cutting tool.
Research features of opening of refractory arsenopyrite concentrates by using low-temperature roasting
Authors: Zvontsov N O , Rogozhnikov D A
Published: November 2020

The article describes an alternative pre-treatment method of refractory arsenopyrite concentrates using low temperature roasting. The process consists of carrying out oxidative roasting in the temperature range of 200–400 °C – relatively low for traditional process. The calculation results of the equilibrium composition of roasting products are presented on the example of a flotation gold-bearing concentrate of the Uderey’s deposit in the HSC Chemistry 6 program. The main concentrate minerals containing gold arepyrite (FeS2) and arsenopyrite (FeAsS). In addition, the concentrate of the Uderey’s deposit is characterized by the presence of antimony in the form of Sb2S3. During the calculations of the equilibrium composition, the optimal conditions for low-temperature roasting were selected. It was found that under these conditions, the dissociation of higher sulfides occurs, arsenic goes into the form of trisulfide (As2S3) and some of the iron goes into the form of sulfate (FeSO4). All this suggests that the process of low-temperature roasting allows to open the refractory concentrate and get a cinder, the further processing of which will not cause special problems: the non-volatile form of arsenic trisulfide will not cause complications when cleaning exhaust gases, and iron sulfate will simplify further leaching processes.
Estimation of selective reduction of iron and phosphorus from manganese ores of different genesis
Authors: Kosdauletov N Y , Roshchin V E
Published: November 2020

The possibility of selective reduction of iron from complex oxides by carbon monoxide gas is investigated. Brazilian ore rich in manganese oxide, ferromanganese ore from the Selezenskoye Deposit (Russia) and concentrate from the Zhayrem GOK (Kazakhstan) were used as samples. Experiments have shown that it is possible to selectively reduce iron from complex manganese ores to a metallic state not only with solid carbon, but also with carbon monoxide. Experimental results of solid-phase reduction showed that at a temperature of 900 °C. With an exposure time of 1.5 hours, the release of metallic iron is detected. At the same time, in the atmosphere with the metal phase, there is no presence of other elements other than iron in the metal. As the temperature rises to 1000 °C, the amount of metallic iron, as well as manganese and phosphorus, increases. At a temperature of 1000 °C, phosphorus turns into metal, despite the type of reducing agent. In all experiments, oxides of manganese, silicon and calcium remained in the oxide part.
Obtaining of niobium-containing ferroalloys from the Russian ore raw materials
Authors: Zhuchkov V I , Zayakin O V , Mikhailova L Yu
Published: November 2020

The possibility of processing niobium-containing pyrochlore-apatite concentrates obtained from ores of Beloziminskoye deposit has been studied. A two-stage scheme for selective reduction of phosphorus into a metal phase to obtain low-phosphorus niobium-containing slag was suggested. The reduction of phosphorus and iron was carried out by a carbothermic method using coke and pig iron carbon as the reducing agent. Pig iron chip and magnetite product (80 % Fe2O3) were used as the precipitating agent. In laboratory and semi-industrial conditions the basic possibility of selective separation and sedimentation of phosphorus (to 91 %) and iron from a niobic concentrate without considerable reduction of niobium (up to 1–2 %), according to the two-stage scheme with minimum possible temperature of process during the first period (∼ 1260 °C) and hot soak at the increased temperature (∼ 1450 °C) during the second period were shown. Obtained low-phosphorus niobium-containing slag after crushing can be used for ferroniobium production according to existing technological schemes.
The problems of application of domestic ore raw materials in the production of ferroalloys
Authors: Zhuckov V I , Leontiev L I , Zayakin O V , Dashevsky V Ya
Published: November 2020

There is a difficult situation with ferroalloy production in Russia – production has a raw material import dependence in the presence of our own large, although not quite high-quality, in accordance with world standards, mineral resource base. As rule, domestic ferroalloy raw materials are of low quality: a low content of leading elements (manganese, chromium ores), a high content of phosphorus (manganese, niobium ores), sulfur (manganese ores). The paper gives examples of a complex of physicochemical studies and the development of a number of alternative technologies for the smelting of new ferroalloy compositions with Mn, Cr, Nb, W. The scientific studies together with the development of the technology have been carried out to study the effect of ferroalloys composition on consumer properties. Because of the fact that the chemical composition of the ores of most new deposits cannot ensure the production of standard ferroalloys. By help deep physicochemical and technological studies it is possible to create new processes and combinations of different types of ferroalloys from non-traditional domestic mineral raw materials. The alloys are not inferior in terms of technical and economic indicators of products obtained from rich imported ore materials.
Influence of technological depressurization on the operation of a cascade pneumatic separator
Authors: Ponomarev V B , Fesun I P
Published: November 2020

The article is devoted to assessing the impact of the technological depressurization of the powdered material dispenser on the work of the cascading pneumatic separator. The results of laboratory tests are presented. The article states that the magnitude of effectiveness and the separation boundary of powdered materials are reduced when working with a depressurized dispenser. The mathematical model of the cascading separator and the results of the computer experiment are presented. The article presents the dependence of the quantity of the product and the content of fine particle classes in the finished material on the amount of relative air flow through the powdered dispenser of the initial product. The change in the granulometric composition of the enriched quartz sand received is shown, depending on the amount of relative air consumption through the powdered dispenser at a fixed air velocity through the upper part of the separator. It was found that the maximum relative speed of air flow through the powder dispenser should be no more than 10–15 %.
Simulation of patterns of crystallizing ingot macrostructure formation
Authors: Sidorov O Yu
Published: November 2020

The electromagnetic, hydrodynamic, and temperature fields of a crystallizing cylindrical ingot with a diameter of 163 mm have been calculated using the finite-difference method. Crystallization has been simulated in an electromagnetic crystallizer. The crystallization rate has been calculated, and then the ingot areas have been divided into small crystals, dendrites and globular ones. Quantitatively, the relationship between the temperature field gradient during crystallization and the ingot structure can be expressed by the following rules: 1) elongated grains of about 10 mm – cooling rate of about 1.8 · 10−4 kg/s; 2) elongated grains of about 20–30 mm – cooling rate of about 0.7 · 10−4–1.8 · 10−4 kg/s; 3) globular grains with a size of 10–20 mm – cooling rate of less than 0.7 · 10−4 kg/s. The possibility of simulation of the ingot structure during its crystallization based on the relationship between the crystallization rate and the grain size has been shown. The influence of the inductor current frequency on the structure of a crystallizing ingot has been simulated. It has been shown that an increase in the current frequency from 5 to 500 Hz leads to the expansion of the area with small crystals.
Methodology of designing an air cascade separator
Authors: Ponomarev V B , Shishkin A S
Published: November 2020

The calculation technique of industrial cascade separators based on experimental and analytical research process methods for air fractionation of bulk materials is considered. The main technological factors and process defining parameters used in calculation of separator design are presented. It is shown that for the design of an industrial separator, it is necessary to find a relationship between the initial granulometric distribution and the fractional requirements for the finished product from the concentration of the material flow and the air flow velocity to the complete cross-section of the separator. The experiment results of material flow concentration influence on division efficiency for various cascade separator constructions are given. Mathematical relationship of the air flow rate through the apparatus on the separation boundary and bulk concentration is proposed. The correlation of these parameters with the constructive sizes of the separator is shown. The initial particle size distribution of bulk, the set restrictions for fractional characteristics of the received powder and the approximating equations of fractional extraction function of fineness narrow classes in a large or small product based on experimental data are used for calculation of the equipment.
Investigation of structure and properties of low alloy steel obtained by wire arc additive manufacturing under various fluxes
Authors: Trekin G E
Published: November 2020

Wire arc additive manufacturing (WAAM) is vigorously explicating direction of mechanical engineering. When using submerged arc welding (SAW) it is possible to apply low-alloy steels with high efficiency and properties, that will allow to use it for manufacture of details and instrument. Microstructure, hardness, distribution of nonmetallic and chemical composition were investigated for SAW build up walls, in as-deposited condition, by low-alloy wire under fluxes with a different basicity. The characteristics of microstructure fixed by an optical microscopic metallography remain practically constant for all deposited weld metals. It is ferrite – martensite (bainite) structure, which has a high dispersibility. The exploration of hardness has shown formation of the partially quenched top with increased hardness and previous thermo- cyclic treated passes with lower hardness. When depositing SAW insignificant saturation of metal with silicium and manganese and a carbon drop occurs. The distribution of nonmetallics is most favorable for additive manufactured material under neutral and basic fluxes. As a result, a comparative research of fluxes was conducted, allowing to make a choice for additive manufacturing of low-alloy work pieces.
A development of computer vision elements for processing the results of tensile tests of specimens and building diagrams of ultimate plasticity
Authors: Erpalov M V
Published: November 2020

The use of specimens with a round notch allows expanding the application of tensile tests in order to study the ultimate plasticity of materials. However the main difficulty in processing the results of experiments is the need to measure the radius of curvature of the neck and the diameter in the minimum cross-section of the specimen. These dimensions determine a stress triaxiality value of the material in the center of the neck according to the Bridgman model or the other ones. This article is devoted to the development of elements of a computer vision system designed to measure the neck, which is formed both on cylindrical specimens and on specimens with a notch. To extract the contour of the specimen and to measure the forming neck, the video recording of the test process on a digital single-lens reflex (DSLR) camera is used. The paper proposes a method for recording the test process using the background, which allows to increase the accuracy of determining the contour of the specimen during subsequent image processing. The Sobel filter is used to extract the contour of the specimen, and a special neck profile equation allows to determine the neck dimensions.
The possibility evaluation of zinc sulphate forms extraction from sludge of PJSC EVRAZ NTMK with following metalloflux obtaining
Authors: Sheshukov O Yu , Mikheenkov M A , Nekrasov I V , Egiazaryan D K
Published: November 2020

EVRAZ NTMK JSC has significant amount of blast furnace sludges, that accumulated in dumps. Chemical and phase analysis of that sludges was carried out. It has shown significant amount of zinc sulphate, which prevents such sludge utilization in a blast furnace. Moreover, zinc sulphate requires a high temperature unit for recycling by common schemes. The possibility of zinc sulphate conversation into oxidized zinc with simultaneous metallized residue obtaining under the common for Waelz process temperatures was confirmed in laboratory. The obtained during laboratory experiments metallized residue is suitable for using in blast furnace as charge addition. The results of a thermodynamic analysis of the zinc sulphate conversion to oxide and the physicochemical basis for the extraction of such zinc forms are presented. Theoretical calculations and laboratory experiments confirmed that sludges with zinc sulphate could be suitable materials for blast furnace. But, sludges of different processes allow to obtain fired briquettes with different physical properties.
Reducing the carbonitride formation risk with increasing titanium dioxide content in the blast furnaces charge of JSC EVRAZ NTMK
Authors: Sheshukov O Yu , Mikheenkov M A , Nekrasov I V , Egiazaryan D K
Published: November 2020

Analyse of the blast furnace charge chemical content changing with the JSC EVRAZ NTMK raw materials base alteration was carried out. That expected change would result in TiO2 content increasing in the blast furnace slags. That increasing would lead to carbonitride formation in the upper levels of the blast furnace, which reduce technical parameters of the blast furnace operation by reducing effective volume of the furnace and derange regular charge moving. Possible ways of that problem solving was shown. It was proposed the complex technology, that affect 3 technological stages: agglomeration, blast furnace process and out-of-furnace treatment of steel. Converting of TiO2 into CaO·TiO2 allows to delay carbonitride formation due to increasing required temperature for that process. In that case, carbonitride formation would move to the tuyere zone of blast furnace, where it increase lining durability. The proposed technology was industrially tested, and the main idea was proved. Few problems were found during industrial tests, but theoretical solving of them was proposed.
The effect of thermoplastic processing on the structure and mechanical properties of metastable austenitic steel
Authors: Ozerets N N
Published: November 2020

The patterns of structural transformations and the change in the mechanical properties of a metastable austenitic steel subjected to cold plastic deformation by drawing with high total degrees of compression and subsequent aging were studied in this work. The studies showed that after quenching, the use of intense plastic deformation by drawing revealed the high technological capabilities of the studied austenitic steel. Austenite in the steel is deformation-unstable and turns into deformation martensite during cold plastic deformation by drawing. Aging of deformed steel causes an additional increase in mechanical properties, due to the separation of the intermetallic phase NiAl from the bcc solid solution (strain martensite). It was revealed that almost carbon-free corrosion-resistant austenitic steel, as a result of correctly selected alloying, combines the advantages of three steels: metastable austenitic steels, Transformation-Induced Plasticity (TRIP)-steels and martensitic aging steels. As a result of using all possible hardening mechanisms, a high-strength state was achieved.
Effect of frictional treatment with a dense cubic boron nitride indenter on the micromechanical properties of the NiCrBSi–Cr3C2 coating
Authors: Soboleva N N , Makarov A V , Nikolaeva E P , Skorynina P A , Malygina I Yu
Published: November 2020

Coatings based on NiCrBSi alloys with Cr3C2 addition can effectively resist wear, corrosion, and oxidation at high temperatures. The use of frictional treatment by sliding indenters as finishing is a modern way to create high surface quality and to enhance the strength and wear resistance of the surface of parts. The article studies the characteristics determined by instrumented microindentation of the surface of a NiCrBSi–Cr3C2 laser clad coating subjected to frictional treatments with a sliding indenter made of dense cubic boron nitride DBN in the air at loads on the indenter of 350, 500 and 700 N, and after grinding. Frictional treatment in the entire considered range of loads contributes to an increase in strength performance, as well as parameters indicating an increased ability of the coating surface to resist elastoplastic deformation. The highest growth of the parameters is observed after frictional treatment at a load of 700 N.
Destruction of cement stone modified with a plasticizer and a nanoscale aluminum oxide
Authors: Gerasimova E S , Trestsova E D
Published: November 2020

It is well known that hydration and hardening of Portland cement are associated with complicated physical and chemical processes, in particular the interaction of clinker minerals with water to form new hydrate phases of different composition. Sometimes the presence of various substances can affect these processes leading to self-destruction of the hydrated cement stone. The morphology and composition of damaged cement stone modified with an additive and with a nanoscale aluminum oxide were studied. It is shown that in the presence of the ‘Linamix PC’ plasticizer and a nanoscale aluminum oxide, well-crystallized Ca(OH)2 plates with an average thickness of 1.5 microns and a length and width equal to 300–400 microns are formed. Also, a network of thread-like ettringite with a diameter of less than 1 micron on the surface of microcracks of cement stone is formed. Most likely the cement stone sample could be damaged by the forces of crystallization pressure during the growth of both Ca(OH)2 and ettringite crystals.
Utilization of final tailings concentration of titano-magnetite ores in Portland cement production
Authors: Kapustin F L , Bashkatov N N
Published: November 2020

When producing iron ore concentrate at Kachkanarsk integrated mining works 2 types of wastes are formed, namely: final tailings of dry magnetic separation (DMS) and final tailings of wet magnetic separation (WMS). Final tailings of wet magnetic separation (WMS) are pulled off or dumped into disposal area up to 45mln tons annually causing great damages to the environment. These final tailings are finely dispersed materials, their chemical composition is oxides of silicon, aluminium, calcium and iron in general. All this allows to use the wastes under consideration to produce Portland cement clinker replacing clayey and iron components in the raw material mixture completely and limestone partially. The replacement of clay with final tailings of ore enrichment are suitable to manufacture clinker raw material mixture allowing to use two-component raw mix instead of three-component and four-component one thus simplifying the technology of cement production and improving the ecological situation in Sverdlovsk region. The utilization of final tailings for concentration of titano-magnetite ores decreases fuel consumption when burning clinker compared to the traditional compositions. Experimental cement meets all the requirements of the Russian Standard 10178 as to their chemical and physic-mechanical properties and have grade 500.
Utilization of ferrochrome slag in concrete production
Authors: Bashkatov N N
Published: November 2020

Ferrochrome slag is waste resulted from the manufacture process of ligature melting. It is a porous material of dark grey-green colour with 2530 kg/m3 density and the open pores size from 1mm to 5 mm. After crushing crushed slag possesses the following characteristics or properties, namely: the least grain coarseness is 20 mm, the largest one is 120mm, the needle and plane grain content is 25.5%, so it refers to ordinary group of crushed stone, its crushability grade is M800, attrition grade AI and frostproofness is F25. Screenings or riddlings obtained by crushing and fractioning of slag possess gradation factor 2.9 and it refers it coarse sand group of class II. Concrete mixes have been investigated by using granite aggregates and ferrochrome ones. It is determined that mixes containing ferrochrome aggregate are stiffer than the traditional ones. In this case strength characteristics of the experimental concretes are 1.7 times higher than those of the traditional concretes. When evaluating approximate cement consumption for concrete made of ferrochrome slag aggregates it was established that such concrete possesses strength of B30 class, but by using granite aggregate in the concrete mix result in strength of B20 class.
Decoding variant for dilatometric measurements of metal samples heating and cooling
Authors: Mikhailov S B , Sharapova V A , Mikhailova N A , Karelova A E
Published: November 2020

Dilatometric measurements in the form of sample sizes registration with temperature changes are widely used in the practice of physical materials science. In recent decades, the hardware component of these measurements has substantially changed with a practically unchanged version of their use as applied to the characteristics of various phase transformations. The basic point, in this case, is the identification of the critical points temperature for the ‘start/finish’ transformations based on the analysis of dilatograms deviations from a tangents carried out in the temperature intervals near the break observed on the obtained experimental curves. However, in most cases, this information has a framework character due to the presence of deficiencies in the critical points temperatures determining. In some cases, to compensate for these shortcomings, results of the changes analysis in the first derivative of dilatometric curves are additionally used. A series of works carried out by the authors is studying the features at changing the temperature coefficient of linear expansion true values. An algorithm for obtaining this spectrum is prescribed.
The effect of elastic deformation on the minor hysteresis loops of low carbon steel
Authors: Mushnikov A N , Gorkunov E S , Zadvorkin S M , Goruleva L S , Kryucheva K D
Published: November 2020

The effect of elastic tensile deformations on the magnetic permeability of a structural low-carbon steel 20K (0.23 % C, 0.20 % Si, 0.46 % Mn) at various magnetic states was experimentally studied. To obtain these parameters, the measurements of minor hysteresis loops, which begin in the demagnetized state and in the remanent magnetization state, were carried out. The maximum tensile stress equal to 250 MPa that corresponds to 90 % of the conditional yield strength of studied steel. Stress dependences of the initial and reversible magnetic permeabilities as well as differential magnetic permeability along the descending branch of the minor hysteresis loop, which starts in the remanent magnetization state, are non-monotonic. They have extremums at σ = 50–70 MPa. However, stress dependences of the sums of those parameters are monotonic. The relative changes reach 25 % at tensile stresses of 250 MPa which make the promise of using the sums of magnetic permeabilities as parameters for assessing the magnitude of tensile stresses.
Analysis of the influence of the parameters of the power supply network on the operating modes of the electric drives of the stands of the hot rolling mill 1700 of ArcelorMittal Temirtau JSC
Authors: Breido I V , Druzhinin V M
Published: November 2020

The finishing group of stands of the 1700 SRS-1 continuous mill of ArcelorMittal Temirtau JSC is characterized by high rolling speeds and high productivity. The use of DC motors as power sources for the main drives of the stands of high-power thyristor converter units significantly affects the nature of the operating modes of the power supply system and the quality of electricity on the buses of the SRS-1 substation. Experiments were performed to study the electricity grid supply substation in which the basic indexes of quality of electric energy and the built waveform voltage SAG during rolling. Voltage dips are observed throughout the rolling process and reach 10% of the rated network voltage. Due to the complexity of removing individual parameters of electric drives and conducting experiments on a real mill, an adequate model of the electric drive of the stand of the finishing group of the 1700 SRS-1 mill was developed and built.
Optimization of the ion-plasma nitriding of structural steel
Authors: Baraz V R , Yurchenkov E A , Ishina E A
Published: November 2020

Mathematical planning was used in order to determine the optimal mode for ion nitriding the structural steel 0.38C–2Cr–2Ni–Mo. This was justified by the requirement to preserve strictly limited functional parameters obtained as a result of diffusion saturation: hardness in the range of 450–650 HV in a layer 0.15–0.40 mm deep. According to of X-ray diffraction analysis in addition to reflections from the matrix phase (alloyed ferrite α-Fe), the reflexes of nitride compounds are recorded, namely, the γ′-phase with a FCC lattice (Fe4N) and the ε-phase with a HCP lattice (Fe3N) with a high nitrogen content. An analytical expression in the form of a linear function for the studied optimization parameters (microhardness and depth of nitration) was obtained by implementing factor planning and regression processing of the obtained data. This made it possible to assess the degree and direction of influence of the investigated factors on the optimization parameters under study.
Technologies for remote lidar sensing of the surface to detect low concentrations of hydrocarbons in Siberia and the far north
Authors: Leshchenko S L
Published: November 2020

The results of research in the field of remote sensing using the technologies of radar and laser detection of hydrocarbons raw materials aimed at the search, localization and topographic location of discovered oil and gas field, the determination of leaks and atmospheric pollution by hydrocarbon gases (e.g. methane) are presented. The main problems with sounding are revealed. To determine the extremely low concentrations of methane in the atmosphere, the main constraining factors were determined and the need to suppress side interference arising on the probing path of the laser beam was shown. To formulate requirements for the sensitivity of equipment and the accuracy of software calculations, the choice of a mathematical model of the path of the laser beam is justified. A modification of the known model is proposed to represent the lidar path based on the differential absorption method taking into account correction coefficients of molecular and aerosol absorption and scattering. Thus, the presented model is a set of methods for providing more accurate and localized data for the implementation of a hardware-software complex.
Iron and steel industry of Russia in the XXI century
Authors: Dokuchaev S V
Published: November 2020

The author states that over the past twenty years, the iron and steel industry of Russia has held its position as one of the key industries of the Russian economy. Technological upgrading of production facilities has minimized the backwardness, however the rapid steel production growth in Asia has resulted in loosing business in the global steel market, while getting more dependent on the market situation. This article deals with the main trends, problems and collisions of the steel industry development in the first two decades of this century. The structure of Russian steel export is reviewed. This work is based on statistical and comparative analysis, ratings and forecasts, as well as theoretical postulates of Douglas North about the close relationship of market economy processes with political and social institutions of the country. The purpose of the article is to show that the industry is facing impending stagnation under the economic sanctions, export dependency of the Russian steel industry and worldwide steel overproduction. The following may be taken as the scientific results of the study: systematization, generalization and author’s assessment of processes in the Russian steel industry and its development prospects, against the background of global trends in the industry.
Resource-saving potential of brick scrap from demolition of buildings
Authors: Domanskaya I K
Published: November 2020

The composition and properties of crushing products of brick scrap of different sizes were studied. It is shown that a large (5–40 mm) and small (0.16–5.0 mm) fraction of brick scrap crushing products may be of interest for replacing natural aggregates, while a pulverized (0–0.16 mm) fraction has pozzolanic activity. The presence of cement masonry mortar in the composition of products for crushing scrap brick walls of buildings is the main obstacle to their use as a large aggregate for light concrete: the average density of crushed brick grains in this case was 890 kg/m3, while for crushed cement grains – at least 1350 kg/m3. With an increase in the degree of crushing of these wastes, their material composition and physical properties are averaged and therefore more suitable for reuse in construction, including as a fine aggregate for mortars. The chemical and mineral composition of brick scrap, studied on the example of a dusty fraction, allows us to predict its good prospects for replacing natural mineral raw materials in the production of firing materials, for example, Portland cement.
Study of the main metallurgical characteristics of iron ore raw materials (sinter and pellets)
Authors: Vitkina G Yu , Dmitriev A N , Alektorov R V
Published: November 2020

The paper presents the results of studies of the chemical, phase composition and metallurgical characteristics of titanomagnetite sinter. The iron ore used in blast furnaces of JSC ‘EVRAZ NTMK’ is titanomagnetite sinter obtained from ores of the Gusevogorsky deposit. Samples of sinter with different basicities as well as with addition of binding polymers in the amount of 300 and 500 g per ton of sinter were investigated. The results of industrial tests of the production and blast furnace smelting of sinter with different basicities and additives of binding polymers are presented on the example of the operation of blast furnaces no. 5 and 6 of JSC ‘EVRAZ NTMK’. It was shown that an increase in the basicity of the sinter from 2.1 to 2.4 and the introduction of a polymer binder (in the amount of 500 g per ton of sinter) positively affect the complex of sinter metallurgical characteristics – durability after reduction, reducibility, softening and melting temperatures, and also decrease the coke rate in blast furnace smelting by 1.0–1.2%.
Improvement in vanadium-containing titanomagnetite processing technology
Authors: Kushnarev A V , Mironov K V , Zagainov S A , Forshev A A
Published: November 2020

The article describes the modern technology of iron smelting from vanadium-containing titanomagnetite. The complex of research presented by the NTMK team and the leading research teams of the Ural Institute of metals, the metallurgical Institute of the Ural branch of the Russian Academy of Sciences, and the Ural Federal University is the basis for achieving high productivity of the blast furnaces EVRAZ NTMK. The presented research and development works are the basis for the technology of metallurgical processing of vanadium-containing titanomagnetite. The developed technology makes it possible to achieve high rates of melting intensity and total consumption of carbon contained in the fuel. Such indicators are achieved by reconstruction, namely by changing the line of the working space of the blast furnace. Modern loading devices were used, energy-efficient technology of coal-dust fuel intake was introduced, and the oxygen content in the air was increased. Considerable attention is paid to the analysis of the domain process and problems of domain melting of titanomagnetite. Particular attention is paid to the implementation of measures to reduce the content of titanium in cast iron.
Plasma hardening of corrosion-resistant steel
Authors: Mironova M V
Published: November 2020

The structure, phase composition and hardness of a 20X13 steel coating treated with two consecutive passes of a plasma arc are studied. It is shown that plasma treatment makes it possible to obtain martensite with a significant (30–50 %) share of permanent austenite in the structure of the local hardening zone. In this case, the hardness of the heat-strengthened blanket is 650–700 HB. The total depth of the local hardening zone with the modified structure reaches one millimeter. The study shows that a homogeneous structure with periodically changing phase composition and hardness develops in the surface layer of 20X13 steel, heat-treated plasma arc. in this case, the plasma arc must pass sequentially with a certain degree of overlap of local quenching zones. It is obvious that by adjusting the parameters of the processing conditions (the current of the plasma arc, the speed of its movement, the degree of overlap of local quenching zones), it is possible to purposefully form a certain structural-phase state of the surface layer with properties that best meet the operating conditions.
Graphite flake cast iron surface hardening
Authors: Mironova M V
Published: November 2020

The influence of the operating parameters of electric arc heat treatment of the surface layer of graphite flake cast iron type CП-61 on the structure, microhardness of structural components and the size of the hardening zone is studied. It is shown that controlling the arc power, its speed and the degree of overlap of local hardening zones allows purposefully forming modified structural States with properties most suitable for specific operating conditions in the surface working layer of cast iron. Overlapping of local hardening zones allows purposefully forming modified structures with suitable properties for specific operating conditions in the surface working layer of cast iron rolls. According to the research results, regularities of formation of the structure and phase composition and properties of the surface layer of cast iron type CП-61 under the influence of electric arc heat treatment were obtained. Control of parameters of the processing mode (power and speed of the arc, the degree of overlap of local hardening zones) allows you to purposefully form modified structures with suitable properties for specific operating conditions in the surface working layer of cast iron.
Evolution of the structure of precipitation-hardening steel during heat treatment
Authors: Safonov E N
Published: November 2020

In order to identify the mechanism of the processes responsible for the formation of the properties of deposited steels of type 15N4M2D2G2AYuF and 20N4M2D2G2YuF, we studied the patterns of formation of their structure and phase composition as a result of heat treatment. The analysis of the results made it possible to recommend tempering at the temperature of 550 °C for two hours as the main mode of heat treatment of these steels. The development of the properties and structure of the deposited steel of the presented type is the result of multi-step interaction of several hardening mechanisms. The main role in the formation of the structure and properties is played by martensitic transformations, as well as solid-solution hardening by interstitial and substitutive atoms. At the first stage, the hardening is caused by the deposition of dispersed intermetallic compounds and carbides. In addition, dispersed particles of intermetallic phases are released at the early stages of aging and slow down the annihilation of dislocations in the matrix. With longer aging, carbides deposited at fixed dislocations contribute to hardening.