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No 5 (2023)
Articles
Vosstanovitel'nyy obzhig chernovogo titanomagnetitovogo kontsentrata mestorozhdeniya Gremyakha-Vyrmes s polucheniem titanovanadievogo shlaka i granulirovannogo metalla
Abstract
The studies results on the reduction firing of rough titanium-magnetite concentrate of the Gremyakha-Vyrmes deposit are presented. The reduction firing of the briquetted charge was carried out on a coal substrate to obtain granular metal and titanium-vanadium slag suitable for subsequent hydrometallurgical processing with the extraction of titanium and vanadium. Studies on reducing roasting were carried out in the temperature range of 1450-1500 °C at different costs of a solid reducing agent — coke. The coke content influence in the mixture and the reduction temperature on the composition of the resulting titanium-vanadium slag has been studied. As a result of solid-phase reduction of rough titanium-magnetite concentrate, optimal conditions for obtaining titanium-vanadium slag suitable for further processing have been established.
3-9
Issledovanie vozmozhnosti pererabotki kaolinovykh glin Suvorovskogo mestorozhdeniya s polucheniem koagulyantov
Abstract
The mineral and chemical compositions of the Suvorov depositkaolin clay have been studied using X-ray phase and atomic emission spectrometry with induction plasma. The conditions of thermal calcination and decomposition of kaolin clay with sulfuric and hydrochloric acids are optimized: the calcination temperature is 650-700 °C; the calcination duration is 60-90 minutes. The extraction degree of Al2O3 from calcined clay into sulfuric acid solutions was 92-94%, into hydrochloric acid solutions — 76-78%. The effect of different flocculants on the separation of liquid and solid phases is investigated. It is shown that the use of polyacrylamide increases the filtration rate by 1.5—2 times. The coagulating properties of aluminum sulfate and hydroxochlorides were studied: oxidizability, color, concentration of aluminum and iron in the treated water. The tested coagulants can be effectively used in the purification of drinking and wastewater at low and high temperatures in a wide pH range of treated waters.
10-14
Struktura i mekhanicheskie svoystva deformirovannykh splavov Mg-Sm-Tb-Zr
Abstract
The structure, aging kinetics and mechanical properties of alloys of the new Mg-Sm-Tb-Zr system with different content and ratio of rare-earth metals obtained by hot pressing have been studied. A different effect of samarium and terbium on the process of recrystallization during deformation and the nature of hardening of alloys during additional aging depending on its duration as a result of the decomposition of a supersaturated magnesium-based solution has been established. The mechanical properties of the alloys after hot pressing and aging, including heating in the temperature range up to 300 °C, have been determined.
15-22
Vliyanie RZE na protsess kristallizatsii silumina zaevtekticheskogo tipa
Abstract
The theories and mechanisms explaining the processes of primary silicon modification in hypereutectic silumins are considered. The processes of crystallization of hypereutectic silumin treated with rare-earth elements (REE): yttrium, ytterbium, samarium, erbium, lanthanum and neodymium have been studied. The temperatures of phase transformations and parameters taking into account the solid phase separation in the crystallization interval have been obtained. Differences in crystallization parameters and the nature of solid phase evolution in alloys modified with yttrium, ytterbium, samarium, erbium, cerium and neodymium are shown. It is concluded that further research is necessary to clarify the mechanism of modification of primary silicon in REE hypereutectic alloys.
23-32
Strukturnye i fazovye izmeneniya v obraztsakh iz plit splava sistemy Al-Cu-Mg pod vozdeystviem korrozionnoy sredy posle ekspluatatsionnogo nagreva
Abstract
The article presents the results of studies on the structure, phase composition, mechanical and corrosion properties of forged-rolled plates made from the structural aluminum alloy of Al-Mg-Cu system in different states. A comparative analysis of the obtained results and the properties of commercial AK4-1 alloy was carried out. It is established that the alloy under study exceeds the analog alloy in terms of the strength properties at room and elevated (up to 175 °С) temperatures on 9-12%. The impact strength of KCU of aluminum alloy of Al-Mg-Cu system is two times greater than that of the AK4-1 alloy. It is shown that the strength and corrosion properties raising after operating heating can be explained by the features of the phase composition and morphology of intermetallic phases including the transition metals phases formed in small quantities in the surface lays of the sample.
33-43
Issledovanie prochnosti, relaksatsionnoy i korrozionnoy stoykosti ul'tramelkozernistoy austenitnoy stali 08Kh18N10T, poluchennoy metodom RKU-pressovaniya. II. issledovanie relaksatsionnykh svoystv i stoykosti protiv mezhkristallitnoy korrozii
Abstract
Relaxation resistance and corrosion resistance of samples of ultrafine-grained steel 08H18N10T obtained by the method of equal-channel angular pressing at temperatures of 150 and 450 °C are investigated. For ultrafine-grained steel with high values of the limit of macroelasticity and yield strength, a decrease in the Hall—Petch coefficient due to fragmentation of δ-ferrite particles at the method of equal-channel angular pressing is shown. It is established that the samples of ultrafine-grained steel have 2-3 times higher relaxation resistance compared to coarse-grained steel. It is noted that the method of equal-channel angular pressing leads to an increase in the rate of general corrosion. At the same time, despite the decrease in corrosion resistance, samples of ultrafine-grained steels have high resistance to intercrystalline corrosion. It is established that the decrease in corrosion resistance of ultrafine-grained steel is due to an increase in the volume fraction of martensite deformation at the method of equal-channel angular pressing.
44-59
Evolyutsiya defektov pri kholodnoy prokatke nizkolegirovannykh splavov molibdena
Abstract
The experimental work briefly describes the technology of multiple electron beam melting, which allows to obtain low-alloy molybdenum alloys with other carbide-forming elements and carbon. Two new alloys described in the work allow deformation by cold rolling up to a thickness of 0.17 mm. Based on the modified Golovin—Sims expression, it is shown that an alloy with dispersed carbides (size 30-200 nm) is strengthened during cold rolling much stronger than an alloy in which only large (≥1 microns) carbides are present. The evolution of continuity defects during cold rolling with an increase in the degree of deformation is traced.
60-70
O tekhnologicheskikh prichinakh poyavleniya bugorkov na metallograficheskikh shlifakh prutkov iz splava MN45-VP
Abstract
Based on the peculiarities of the copper-nickel alloy of vacuum melting Cu-45%Ni such as “constantan” (Russian abbreviation “МН45-ВП”), the reasons for the appearance of characteristic "tubercle" on the metallographic cuts of its rods as a type of surface effect of the "mustache" type are revealed. It has been shown that the formation of "tubercle" is a manifestation of diffusion processes caused by increased unevenness of the chemical composition of material. It is also indicated that the reason for this heterogeneity is due to the absence of special electromagnetic devices in the composition of the induction melting furnace for mixing the melt, the components of which are separated by indicators of magnetic susceptibility, i.e. the duration of the melt exposure during cooling during degassing is insufficient.
71-75
Issledovanie udel'noy elektroprovodnosti reniysoderzhashchikh rastvorov karbonata ammoniya i raschet ee energii aktivatsii
Abstract
The specific electrical conductivity dependence of aqueous solutions of ammonium carbonate and solutions of the ammonium carbonate—ammonium perrenate system on the reagents content in the range of their concentration of 0.1—1.8 mol/l for (NH4)2CO3, 0.01—0.1 mol/l for NH4ReO4 and solution temperatures in the range of 20-50 °C were investigated by the conductometric method. A linear increase in electrical conductivity with an increase in the temperature of electrolytes and a nonlinear increase with an increase in the concentration of reagents was revealed. The temperature coefficients values of electrical conductivity and the activation energy values of electrical conductivity in the studied range of concentrations and temperatures are calculated. A decrease in the activation energy of electrical conductivity with an increase in the temperature of the solution was noted. The calculated value of the activation energy of electrical conductivity indicates the diffusive nature of charge transfer.
76-84
Issledovanie kineticheskikh kharakteristik tverdofaznogo prevrashcheniya splavov Kh30N60M9 i Kh23N65M13 v temperaturnom intervale 500-650 °C po dannym termogravimetricheskogo analiza
Abstract
The results of the study of the structural states of single-phase alloys Kh30N60M9 and Kh23N65M13 for the conditions of heating samples at a rate of 1.0 °C/min are presented. The structural states of the alloy samples were obtained by water quenching; the alloy quenching temperature was 1107 and 1135 °C, respectively. The article presents the results of thermal analysis of samples of the considered alloys in the conditions of an inert gas - argon, without carrying out its additional purification from oxygen, the volume fraction of which was up to 0.003 %. As a characteristic of the structure state, an indicator of the rate of weight gain is proposed. According to the experimental results of weight gain, an original method for calculating this kinetic indicator as the rate of solid-state transformation, then the conversion coefficient (k) is proposed. The true values of weight gain considered are referred to the true values of temperatures in the temperature range of 500-650 °C, when the scales of variables and values of variables are proposed in the range of true values (0..1). As a result of the work, confirmation of the improved thermophysical characteristics for the Kh30N60M9 alloy in the considered temperature range was found, in comparison with the Kh23N65M13 alloy. The calculated indicators of the conversion coefficients of the alloy samples were confirmed by experimental data on the amount of enthalpy in the considered gradations of the temperature range, for which the areas under the DTA graphs of the Kh30N60M9 and Kh23N65M13 alloy samples were calculated for the conditions of heating the samples at a rate of 1.0 °C/min. It was found in the work that the decomposition of the solid solution structure is more inherent and essential for the structure of the Kh23N65M13 alloy in the temperature range of 500–650 °C.
85-92
Razrabotka metodik i eksperimental'nykh ustanovok dlya opredeleniya teploemkosti zhelezorudnykh materialov
Abstract
One of the most important thermophysical pellets characteristics is considered — their heat capacity, which affects the technological production process of iron ore pellets at the stage of their heat treatment in a layer on a conveyor belt. Since the physical heat capacity of materials is determined by the enthalpy value, the mixing method is used to measure the latter, which is implemented on an installation with an adiabatic calorimeter. The research object is Kachkanar pellets of different basicity. The average values of the pellets enthalpy and their physical heat capacity, taking into account changes in the phase and chemical composition of the material, are presented in the interpolation equations form. The temperature dependences of the apparent heat capacity of pellets of various basicity at different heating rates were determined using a newly created experimental setup that allows determining the complex of thermophysical characteristics. Estimates of the enthalpy change and the dependence of the apparent heat capacity on temperature for fluxed and unfluxed concentrates of Sokolovsko-Sarbaysky mining and processing plant were carried out on an experimental installation using the method of quantitative thermal analysis. The presented methods for determining the enthalpy and heat capacity of iron ore pellets and concentrates, as well as the designs created for the implementation of these methods can be used to determine the heat capacities of various materials of metallurgical production and to optimize the operating parameters of their heat treatment.
93-101