bluuebunny/crossref_metadata_2025_split 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.