The article provides a detailed analysis of research results on the use of various types of titanium raw materials from Russian deposits: primary (titanomagnetite, ilmenite-titanomagnetite), metamorphosed (buried leucoxene and ilmenite-leucoxene sandstones) and complex zircon-rutile-ilmenite placers. All titanium deposits in Russia are characterized by low ore quality, which does not meet technological requirements for the production of pigment TiO₂ and metallic titanium. Main deposits are based on titanomagnetites containing from 3 to 17 % of TiO₂ . Ilmenite is in a subordinate position. Leucoxene sandstones of the Yarega deposit have high titanium content (about 10 %o TiO₂ ). But when they are dressed by known methods, low-quality high-silicon leucoxene concentrates are obtained containing 40 - 50 %o TiO₂ with significant titanium losses. Ilmenite-leucoxene sandstones of the Pizhemskoe deposit contain 3 - 10 %o of TiO₂ . The main titanium-containing phases are pseudorutyl Fe₂O₃ 3TiO₂ and leucoxene. The cementing binder of grains in sandstones is siderite with magnetic properties, which greatly reduces the degree of minerals disclosure during crushing and worsens the conditions for ore dressing in general. Ilmenite-bearing placers consist of fine-grained disseminated ilmenite and are difficult to concentrate. Complex zircon-rutil-ilmenite placers are infected with chromium and other undesirable impurities, which do not allow existing dressing methods to obtain a conditioned ilmenite concentrate. The main problems of using hard-to-concentrate titanium ores of all the above types of deposits and scientifically based ways to solve them are discussed. It is aimed at obtaining high-quality raw materials for the production of titanium metal and pigment TiO₂ with the simultaneous extraction of other valuable components. Particular attention is devoted to studies on the use of mass complex raw materials - titanomagne-tites, which are allocated in three phased directions, lasting for about 200 years - from the beginning of the XIX century to the present.

To estimate the size of the drops formed on individual bubbles of the reducing gas during the oxide melt barbotage, a metal phase formation model was used. This model includes the following stages: formation of bubbles upon injection of gas into the melt; metal recovery on the bubbles surface and its concentration in the form of drops in stern. Equations are presented that make it possible to estimate the limiting sizes of a gas bubble (R^кр_п) and drops (r^кр_к) moving in oxide melt without crushing. Using the densities (p, kg/m³) and surface tension (σ, mJ/m²) of B₂O₃ - CaO (1) and B₂O₃ - CaO - CuO (2) melts in the temperature range of 1373 - 1673 K, described by the equations σ₁= 87,0 + 0,242T, p₁ = 3,2610-3 - 0,91T, σ₂= 10,8 + 0,178T, p₂ = 3,1910-3 - 0, 70T, respectively , the critical dimensions of a gas bubble (R^кр_п)moving in an oxide melt without crushing were calculated. In B₂O₃ - CaO - CuO melt, critical radius of the bubble varies from 0.047 to 0.053 m depending on temperature, and for the B₂O₃ - CaO system these values are 0.06 - 0.081 m. Using a technique with thermodynamic equilibrium calculations that allows to describe the features of oxide melt barbotage by various reducing gases, we determined the change of the copper oxides content in B₂O₃ - CaO - CuO melt depending on the amount of CO introduced at different temperatures. Based on the obtained data, the amount of copper formed during the interaction of Cu₂O in the melt with a single CO bubble wascalculated depending on the content of copper oxide and the amount of CO in the bubble. The correlation dependences of the drop size on the content of Cu₂O in the melt (C_{Cu O}, %), temperature (T, K) and the amount of CO in the bubble (n_CO , mol) were obtained by statistical data processing methods.

The authors have investigated key technological parameters of stable production of IF steel sheet with BH-effect. The features of ultralow carbon IF steels and IF steels with BH effect are described. Scheme of IF-BH steel hardening during hot drying of the car body after painting is considered. Data on the chemical composition of IF and IF-BH steels produced at Russian and worldwide enterprises are presented. The authors have analyzed the reasons of appearance of such a defect in the steel sheet as slip bands that arise when the yield area appears on the tensile diagram of steel samples. The requirement on the “shelf life” presented to the IF-BH steel grades is given and disassembled. The article considers the formula for calculating effective carbon content in steel based on the total carbon content in steel, niobium, titanium and nitrogen. The range of carbon effective in steel is given to achieve the optimal value of the BH effect based on previously published works. The results of industrial IF-BH steel production have been analyzed for the conditions of Russian enterprise and recommendations were given on criteria such as the optimum carbon content range in solid solution, the recommended maximum total concentrations of carbon and nitrogen in steel, and the BH effect value guaranteeing a high yield of IF-BH steel sheet in the production. Calculations of various options of microalloying by titanium and niobium for IF-BH steel were done. Criteria are formulated that allow stably obtaining a given value of the BH effect in cold-rolled ultralow-carbon steels. A two-stage scheme for microalloying by titanium and niobium is proposed. The influence of grain size in sheet steel on the presence and value of the BH effect is described as well as on the presence/absence of a yield plateau on the tensile diagram in the sheet metal in the initial state.

The main problem of ferroalloy production in Russia is the availability of ore raw materials in domestic factories. Only a few types of alloys are produced from our own raw materials (such as ferrosili-con and vanadium alloys). Most ferroalloys are either imported from abroad or smelted from imported raw materials. The difficult situation in domestic ferroalloy production is associated with raw material import dependence. Despite the presence of its own large mineral resources base, although not quite high-quality in accordance with world standards. Domestic ferroalloy raw materials have a low content of leading elements (manganese, chromium ores), a high content of phosphorus (manganese, niobium ores) and sulfur (manganese ores). This requires a conduction of physical and chemical studies and the creation of a number of new alternative technologies. The work shows that it is possible to create new processes and combinations of different types of ferroalloys from non-traditional domestic ore raw materials based on deep physicochemical and technological studies. They are not inferior in terms of their technical and economic indicators of products obtained from imported materials. To successfully solve the problem of providing the ferroalloy industry with domestic ore raw materials, it is necessary to combine the research of geology, enrichment and metallurgy.

Currently, the technology of resonant-pulsating metal refining (RPR) becomes more widely used for refining cast iron and steel. The paper highlights the stages of development of resonant-pulsating refining to improve the quality of products and presents the results of physical and mathematical modeling of metal refining with nitrogen and argon. It is established that physical modeling gives a good qualitative picture of the processes of metal blowing in the ladle by tuyeres of various designs. Mathematical modeling allows us to quantify the optimal parameters of blowing with argon and nitrogen in ladles of different capacities, depending on the ladle size and on diameters of tuyere and pulsator. The influence of this type of metal blowing on gas content, microstructure of cast iron, its mechanical and performance properties of products made of it was evaluated. It was found that the strength properties of cast iron increased from 91 - 105 to 130 - 170 MPa, the hardness increased from 137 - 150 to 163 - 182 HB, and the density also increased from 6890 - 6900 to 7000 - 7200 Kg/m³. In addition, it should be noted that the use of the presented technology can significantly reduce the harmful effects of phosphorus. The operational stability of products made of blast-furnace cast iron has reached the best domestic and foreign indicators. This technology has also proved to be effective in continuous casting of steel on high-grade casters. It made it possible to achieve the best performance in the industry with minimal costs during implementation. The developed technology is easy to implement on existing steel non-furnace processing units and on continuous steel casting machines. It can be widely used in foundries, electric steelmaking and oxygen-converter shops.

Explored reserves of titanomagnetite ores of Suroyamskoe deposit in Chelyabinsk region is equaled to 11 billion tons. Construction of a new metallurgical enterprise may be relevant for their production and processing. The most promising is the traditional scheme of metal production: ore mining, its crushing and enrichment, production of agglomerate and pellets from concentrates, smelting of pig iron in blast furnaces and steel production in oxygen converters. To establish basic technological parameters of the new production scheme, pig iron smelting from sinter obtained from titanomagnetite ores of Suroyams-koye deposit and its further devanadation (to produce vanadium slag suitable for the production of ferrovanadium) were studied in laboratory conditions of Nosov Magnitogorsk State Technical University. At the initial stage, a calculation was carried out, than experiments in laboratory conditions were made. As a result, the technology was developed for smelting pig iron from sinter obtained from concentrate of Suroyamskoe deposit and its subsequent devanalization to produce two products: pig iron and vanadium slag. It has been established that it is advisable to obtain vanadium in it at least of 0.22 % when smelting pig iron. Dependences of the main indicator of devanadation effi-cience - the content of vanadium oxide in slag - on the concentration of vanadium in pig iron and the amount of slag were found. The fundamental possibility of de-exploitation of experimental Suroyamskii pig iron was confirmed with the production of vanadium slag containing up to 12 % V₂O₅ with the use of air blast as an oxidizing agent.

Heat-resistant nickel-based alloys are widely used in the domestic aircraft industry, rocket engineering, and instrument making. Increasing the basic mechanical and operational characteristics of the metal is achieved mainly by alloying the base with various elements such as rhenium, ruthenium, hafnium, etc. However, increasing the operational properties can also be achieved by metal nitriding, as a result of which interstitial solid solutions are formed (finely dispersed nitrides), which increase the strength of the alloy. The work is devoted to the study of nitriding process of nickel-based complex alloys. Various options of the interaction of nitrogen with the melt are considered under conditions of open melting and processing with low-temperature nitrogen-containing plasma. The use of plasma-arc remelting allows one to obtain various types of gas in form of atoms, ions and molecules in plasma. The first two forms are much more active than molecular nitrogen, which leads to super-equilibrium concentrations in the alloy. A thermodynamic analysis of nitrogen solubility in a nickel-based melt was performed during open melting and under plasma-arc remelting. The nitrogen solubility in model EP741NP alloy was calculated depending on the partial pressure of nitrogen above the melt surface and in the plasma-forming gas. It was shown that treatment of the melt with nitrogen-containing plasma makes it possible to obtain higher content of nitrogen in the alloy. In this work, temperature of the metal in the zone of contact with plasma arc was estimated using the technique according to which the evaporation of the melt components from the arc spot area occurs when the metal boiling point is reached.

Alloys containing rare-earth metals (REM) are increasingly used in production of steels and alloys. After modification and microalloying of steel with REM, structure of primary metal is refined, its mechanical characteristics are upgraded, concentration of oxygen dissolved in liquid iron is decreased significantly, and originated nonmetallic inclusions do not exceed several microns in size and are of predominantly globular shape. Due to relatively high cost of REM, it is proposed to calculate their consumption at each stage of technological process to determine optimal amount required for deoxidation or modification. In this work, thermodynamic modeling of phase equilibria in liquid metal of Fe - La - Ce -Al - O system has been performed. The authors provide a base of thermodynamic data of the system under study: temperature dependences of the equilibrium constants of reactions between the components, values of the first-order interaction parameters (according to Wagner) for elements in liquid iron, values of energy parameters of the theory of subregular (for oxide melt) and regular (for solid solution) ionic solutions. Based on coordinates of calculated isothermal (1600 °С) isostructural (0.01 wt. % aluminum) cross section of solubility surface of components in metal (SSCM) of the Fe - La - Ce -Al - O system, lanthanum and cerium flow diagrams were constructed for various initial oxygen concentrations (metal is pre-deoxidized with aluminum). It has been shown that costs of expensive REM used in microalloying and metal modification strongly depend on composition of the initial metal.

In recent years, the unique physicomechanical properties of highentropy alloys (HEA) have been the subject of increased attention of Institute of Metallurgy, Ural Branch of RAS, Ekaterinburg, Russia  researchers. The study of the thermodynamic characteristics of such materials may be of interest for formulating the principles of formation of structures with the necessary functional characteristics. Since the processes of structure and phase formation, as well as the diffusion mobility of atoms, the mechanism of formation of mechanical properties and thermal stability are significantly different from similar processes in traditional alloys, that is why HEA are allocated to a special group of materials. Of particular interest are high-entropy alloys based on transition refractory metals such as Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W. Light metals such as Ti, V, and Cr are usually selected to reduce the mass density; refractory ones such as Nb , Ta and W, are primarily responsible for the strength characteristics of the entire material. The paper provides a brief overview of results of the study of high-entropy alloys in the new laboratory of Institute of Metallurgy of UB RAS in 2019. Two groups of alloys were studied: HEA of the AlNbTiVZr type containing low-melting aluminum and HEA of the (Ti, V) ZrNbHf (Ta, W) type containing exclusively refractory transition metals. By varying the ratio of components in the first group of HEA, the existence limits of disordered regions of solid solution and intermetallic compounds characteristic of this system were established. For the second group of HEA, a forecast is made of the phase composition, properties and structure based on quantum-chemical calculations involving first-principle molecular dynamics. The forecast showed the possibility or unlikely formation of a disordered solid solution in the above systems with the presence or absence of specific chemical elements.

Duplex Stainless Steels (DSS) are currently widely used in petrochemical industry, in which austenite and ferrite are in equal fractions, thus providing for a favorable combination of mechanical properties along with high corrosion resistance of these steels. The development of new DSS compositions is searching of a compromise. Increasing the chromium content in steel provides its higher corrosion resistance, but in order to maintain phases balance, nickel concentration have to be raised, that causes the formation of undesirable о-phase. To exclude its formation, nickel is replaced with nitrogen which induces the formation of unfavorable chromium nitrides. In the present work, thermodynamic criteria for the reasonable choice of chemical compositions of advanced DSS were developed: 1) austenite and ferrite should be in equal fractions at the beginning of hot plastic deformation; 2) temperature of the о-phase formation beginning should be below the temperature of the end of hot plastic deformation; 3) onset temperature for the beginning of chromium nitrides formation should be minimal. The success of these criteria was studied under the influence of primary and secondary alloying elements for DSS, and the results of these studies have been generalized using multiple regression equations. It has been revealed that the chemical composition optimization of well-known commercial DSS grades, as well as the development of new grades with specified properties can significantly benefit from the use of these equations. Hot physical experiments have shown that thermodynamic modeling well describes the ferrite content found in experimental steels of different compositions at different quenching temperatures.

The possibility of structural transitions in the metal melts is discussed based on analysis of the temperature dependences of their viscosity, electrical resistance, and surface tension. Mechanism of structural transitions in complexly alloyed melts consists in destruction of microinhomogeneity not only of the structure, but also of the chemical composition. Anomalies in the temperature and concentration dependences of the structurally sensitive properties of metal melts - viscosity, density, electrical resistance, and surface tension - are caused by a change in the melt structure. Branching of the temperature dependences of the structurally sensitive properties of such melts is explained by an irreversible violation of the microinhomogeneous state inherited from the initial multiphase chemically inhomogeneous ingot. Microinhomogeneities that arise due to the predominant interaction of singlesort or not single-sort atoms correspond to short-range order violation in atomic arrangement (SRO) and to a range of 2 - 5 A. Microinhomogeneous state of the metal melts is caused by the segregation of atoms of fluctuation nature without clear interphase boundaries (by clusters), and is associated with violation of the middle order (MRO) and with a range of 5 - 20 A. Microheterogeneous state of the melt, which is characterized by the presence of dispersed particles enriched by one of the components suspended in an environment of a different composition and separated from it by a interfacial surface, corresponds to the long-range order (LRO) and to a range of more than 20 A. Structural transitions in metal melts can also be understood as “liquid - liquid” phase transitions in terms of competition between two homogeneous liquid phases, which differ in the magnitude of the enthalpy, which varies with increasing temperature. Liquid - liquid phase transitions are observed depending on the temperature background of the melt. Branching of the temperature dependences of viscosity, density, and surface tension, measured during heating and subsequent cooling of the melt, is also the result and evidence of the liquid-liquid phase transition. The author proposes an algorithm for a priori analysis of the temperature dependences of viscosity, electrical resistance, and surface tension of complexly alloyed melts based on their structure.

The significance of the new theory of metal reduction from ores has been demonstrated. It was shown that all the existing versions of the theory are based on atomic-molecular representations of the early 20-th century where reduction is considered as a process of exchange of oxygen atoms between a reducing agent and oxide molecules. These representations do not take into account changes in the crystalline structure of oxides and in the state of a gas medium with change in temperature and pressure. The attention here was drawn to the absence of molecules in oxides, and atoms in metals. Inconsistency of a number of the theory conclusions with practice of reduction during operation of plants was revealed. Based on the assumptions of redox reactions as processes of exchange of reagents by the valence electrons, defective ionic structure of real crystals, changes in the state of the gaseous medium during heating and pressure increase using some statements of quantum mechanics on the distribution of electrons in solids, the authors have developed electron version of the reduction theory. This theory is based on the unity of the anionic sublattice of all crystals of the oxide phase and the collective electronic system of all valence electrons of metal cations in oxide. It is shown that in the reduction plants, due to the thermal ionization of gases and thermionic emission from the surface of the heated bodies, the gas medium is plasma. The presence of charged particles in the plasma ensures their interaction at a considerable distance and the course of chemical processes in the kinetic mode. The gaseous reduction products are removed from the reaction zone with exhaust gases, and the electrons released in the plasma are absorbed by the oxide surface and exist in the oxide together with the anionic vacancies that arise when oxygen is removed. In high-grade ores the vacancies merge and disappear on the oxide surface, and the free electrons of the vacancies combine the nearest cations with a metal bond to form a metal shell which later turns into carbides. The formation of carbide shells blocks the oxide surface and stops reduction. When temperature rises and the shells melt the reduction process resumes. Therefore, the carbon-thermal reduction produces cast iron and high-carbon ferroalloys. In low-grade and complex ores the vacancies are scattered in the oxide volume along the total anionic sublattice forming solution of vacancies and free electrons. The vacancies merge and disappear in places of increased concentration of cations where the Fermi level of atoms is less than the chemical potential of the free electrons. In the formed anionic void the free electrons rearrange metal cations with low Fermi energy and bind them with a metal bond bypassing the stage of atom formation. Crystal growth in an anionic void occurs without resistance from the parent oxide phase.