One of the promising trends of the perfection of the existing technologies is the development of the technologies of alloying and modification of steel oxide, including natural materials. Such materials are the bariumstrontiumcontaining carbonate ores, the nickel concentrates and converter vanadium slag, whose use makes it possible to obtain metal with the improved properties, at the same time from the process is excluded the stage of obtaining ferroalloys and masteralloys, which is characterized by significant expenditures. For improving the existing metallurgical processes the significant studies are required, which can be accomplished with the use of methods of thermodynamic simulation. In the article the results of thermodynamic simulation in the elementary systems of the reduction processes of barium, strontium, vanadium and nickel from their oxides from different restorers are given. The obtained results made it possible to explain the possibility in principle of the realization of the processes of microalloying and modification of steel by inexpensive materials and to determine type and optimum expenditures of restorer. As the tool with the thermodynamic simulation was used the program set “TERRA”, which allows on the basis of the principle of the entropy maximum defining equilibrium classification of multicomponent heterogeneous system for the high-temperature conditions. As the restorers were examined carbon, silicon and aluminum. Studies of the effect of temperature and expenditures of restorers for conditions and regimes of the reduction processes of metals were carried out. The results of investigating the reduction processes of barium and strontium have shown that as the restorer during the application of the oxide barium-containing materials for the treatment of steels is more preferably to use silicon or aluminum. The optimum expenditures of restorers were determined, which ensure the maximum degree of the reduction of barium and strontium. The studies were carried out and the possibility of nickel restoring by carbon was confirmed. The results of investigating the process of vanadium reduction confirmed the realizability of process both separately by silicon and by carbon and by the joint carbon-thermal reduction, during which carbon is the predominant restorer. The use of obtained results will make it possible to develop the new resource-saving technologies with the use of oxide materials for the alloying, microalloying and modifications of the fusions of the system Fe – C.

As it is known, titanium alloys due to a number of features (high specific strength, fatigue resistance, fracture toughness and corrosion resistance) are widely used in aerospace engineering, including ribbed panels. For products of this kind it is necessary to meet high requirements of quality of welded joints and dimensional accuracy of the construction. Fusion welding of titanium alloys results in the formation of inhomogeneities in the connection zone and in the reduction of technological and operational performance. The geometric dimensions of design are distorted due to occurrence of welding stresses, pores and microcracks appear in the weld metal, mechanical properties and other parameters are reduced. These facts require a comprehensive analysis of the manufacturing process of titanium ribbed panels: from the manufacturing of semi-finished products to the final stage of heat treatment of the finished product from the point of detection of the most significant in relation to defects in operations. The blank manufacturing operations, including their preparation for welding, welding and subsequent heat treatment regimes affect the cyclic and static strength of welded ribbed titanium panels depending on the number and total area of welding defects. The article presents the research that allows to predict the properties and reliability of welded structures and to achieve identity of the properties of basic metal and weld metal with the lack of a guarantee of both internal and external defects, depending on the choice of the complex technological measures. It is shown that a certain welding cooling rate in the range of phase transformation temperatures, finish milling, running and cleaning (degreasing and dehydration) of the surface of abutting edges, low annealing after welding in the air and subsequent sand cleaning; GLC in the auxiliary gas medium of nitrogen or argon or the combined GLC blanks and cutting by milling determine correspondence of properties and reliability of the welded joints of base metal of ribbed panels from VT20 alloy.

Calibrated metal is presented as an effective form of blanks for a number of metal technologies. Greater its use in industry prevent residual stresses formed during cold deformation. The aim of this study was to determine the main calibration parameters that influence the formation of residual stresses. The main components of the tensor of residual stresses in a calibrated rod were determined by the method of grinding and boring of one cylinder. The planning methodology of multivariate experiments was used to determine the effect of the main parameters of the calibration process on the residual stress state. For the account of simultaneous effect on the residual stresses of the relative compression, angle of the working cone of the die, calibration speed and lubrication quality the fractional four-factor experiment has been planned and implemented. These experiments have shown that the parameters of the calibration process significantly affect the residual stresses, which vary not only in magnitude but also in sign. Experimental results have shown that the range of angles of the die was from 8 to 24°, the tangential and axial residual stresses increase simultaneously: increase by 2.3 and 1.8 times. With the increase in the length of the gauge zones maximum axial residual tensile stresses are reduced by 52 % and tangential increased by 21 %. The influence of the main parameters of the calibration process on the size and nature of the distribution over the cross section of cylindrical rods of axial, radial and tangential residual stresses was determined. Changing the sign of the residual stress depends on the deformation parameters and occurs at a depth of (0,5  –  0,8)r/R. It was revealed that at the calibration mode that is used in the production the axial and tangential residual tensile stresses are formed in the peripheral layers of rods at cold forming, and in the central layers – the compressive stresses are formed. Radial residual stresses at the surface are zero, and in the rest of the body volume residual stresses are compressive.

Difficulties in determining the flow resistance of layer of pellets in the burning conveyor type machines during the heat treatment, associated with significant changes in the layer structure due to its shrinkage during the drying process, the low strength of raw pellets, adjustment layer segregation, sintering and melting of pellets, were considered. As a result, flow resistance of pellets layer on conveyor machines greatly exceeds the resistance value which is obtained in laboratory tests of gas dynamics of pellet layer. According to the impact of many factors on the structure of a burnt pellets layer, which can be taken into account only in their cumulative effect, the authors have introduced the concept of an equivalent porosity. As a result of calculating the amount of equivalent porosity with the available literature data and the data obtained in working out the pellets burning technology in a high layer on Kachkanar conveyor machines, a pattern of its distribution along the length of the conveyor machine was revealed. It was established that most significantly the porosity of the layer reduce due to layer shrinkage in the drying zone and cracking of pellets at the outlet of it. The analysis of estimated expressions to determine the gas-dynamic characteristics of the pellets layer helped to get the dependencies that with a sufficient degree of accuracy can be used to calculate the gas-dynamic characteristics of the layer on the conveyor machines considering different porosity. The obtained results can be used in determining the gas dynamic and thermal conditions, providing work of burning conveyor machines with low specific fuel consumption and high quality of the calcined product.

The paper describes the developed technology of the creation of wear-resistant surfaces of friction pairs, which have oil pockets for the holding of lubricants, which are situated between rollers, formed on flat surfaces with the help of a fast-rotating disk. The treatment of friction surface is performed by the disk of the thickness of 6  –  15  mm with reinforced working surface of solid VK-8 alloy. The disk rotates with the surface velocity of 50 – 150 m/c, it is pressed with the pressure of 1.2 – 40.0 MPa. It also shifts along the treated surface with the velocity of 3 – 30 mm/c. In the local treatment zone the metal of the processed surface, which has a ferrite-pearlite structure, is heated up to the temperature of 1100 – 1200 °С and transfers into an austenitic condition. Then the disk is moving beyond the treatment zone, the heated layer is chilled sharply by means of heat transfer into the mass of the detail. The structural transformation of austenite into martensite happens with the change of crystal lattice from the face-centered cubical lattice into a body-centered tetragonal one with the increase of the volume of heated metal. The increased volume, limited with the metal from three sides of the detail, is pressed above the treated surface up to the height of 0.3 – 1.5 mm and forms a buckled roller of martensite behind the moving disk. Here one can observe compressing stress and the degree of deformation up to 240  %. The rollers are formed along the whole surface from the edge to the edge in the direction, which is perpendicular to the motion of the workpiece during the operation process. Inclined (wedge-like) working surfaces of rollers provide the hydrodynamic supporting forces at sliding velocity of friction surfaces, which is more than 2 – 3 m/c (liquid lubrication), but supporting surfaces of rollers are made of a very hard material, allowing keeping wear-resistance in the conditions of boundary lubrication at slow sliding velocities of friction surfaces (less than 2 m/c).

The audit of the technological process of 20GFL steel melting in arc furnaces with the capacity of six tons in Rubtsovsk branch office of JSC “Altaivagon” has revealed some problems connected with defects of mechanical properties of steel. The chemical composition of the researched samples is within the established State Standards. To confirm this fact and to reveal the cause of the defect problem the authors of the article have conducted the statistical analysis of the influence of chemical composition on the quality characteristics of mechanical properties of metal. To conduct the regression analysis and to build the model of forecasting the following algorithms there have been used: Linear Regression (LR), Random Forest (RF) and Support Vector Machine (SVM). The solution of the problem connected with the steel defects by mechanical properties has been offered with the help of forecasting models. As the result it has been established that there are some possibilities to forecast and to control mechanical properties of steel along its melting. When receiving the forecast of defects by one of the parameters, assuming the current values of the content of chemical composition and the final conditions, one can calculate the chemical composition of steel, which can be reached on the considering melting and which will assure the absence of defects. It has been established that for the analysis of tendencies of steel quality of cast products one can use two key indicators out of two groups of mechanical properties – yield point stress σт and impact hardness КСV. Schematic control of the quality can be fulfilled by timing diagram of mean removal chart of the controlled parameters by the defect from its border value in standard defections. The indicator of good quality and the risk minimization is the output of the timebase diagram from the two standard defections.

The paper presents the results of complex researches of 40Cr13 stainless steel. Using the methods of optical, scanning and atomicforce microscopy, micro- and nanostructures have been obtained, as well as has been given the comparison of the received images of structures and phase states of steel in three different states (after annealing, hardening and high-temperature tempering) with the results of electron and optical microscope investigations. The received optical images of a ferrite-pearlite structure of a valuable content of globular carbide with the composite of (Сr, Fe)₂₃C₆ , received after annealing, are given in comparison with the research results of scanning and atomic-force microscope investigations. It has been shown that the use of atomic-force and scanning electron microscopy in this work allows to make conclusions on steel microstructure, which coincide not only with the data of optical metallography but also exceed the latter in specification of structural characteristics. The usage of scanning electron microscopy allows establishing that large carbides are situated along the borders of ferrite grains. There are also some number of carbides inside the fine grains of ferrite; the sizes of inclusions have been defined. After hardening there are some structures which consist of macroacicular martencite. The usage of the images of atomic-force microscopy allows receiving the structure with the expressed acicular structure in comparison with scanning electron microscopy with the possibility to build visual 3D-images. The form of undissolved carbides is also globular. The sizes of martensitic lamella have been defined. The steel structure after high-temperature tempering (secondary sorbite) is formed as the result of the cracking of martensite on ferrite-carbide mixture with the formation of carbides of right round shape. The formed single and line carbides contain strong carbide-former – chromium (Сr, Fe)₂₃C₆ . It was confirmed by the results of spectrum analysis. Such structure differs from martensite in higher strength. For all the states the authors have given the results of mechanical tests by the scheme of axial extension, as well as have defined the HB hardness.

The thermodynamic calculations have been performed to study the influence of silicon (0.1 – 0.8 %), aluminum (0.005 %) and carbon (0.1 %) contained in the metal on recovery process of boron from slag with the basicity equal to 5, at temperatures of 1400 – 1700 °C with the help of software package HSC 6.1 Chemistry (Outokumpu). The experiments of interfacial distribution of boron between slag system of СаО – SiО₂ – MgO – Al₂O₃ – B₂O₃ and metal have been carried out in a high temperature electrical resis­tance furnace of Tamman. The low-carbon steels with different con­tents of silicon were the base metal. The results of thermodynamic modeling and experimental data have shown that direct microalloy­ing of steel with boron are crucially possible due to boron reduce with the help of silicon in metal. The reduction of boron with slag is possible with the help of silicon in metal and the process was theo­retically based and experimentally studied. The results of thermody­namic modeling indicate the possibility of thermodynamic recovery of boron from the system of СаО – SiО₂ – MgO – Al₂O₃ – B₂O₃ with the help of silicon, despite its low (0.1 – 0.8 %) concentration in the metal. The increase of the initial silicon content in the steel increases the concentration of boron in the reduced metal. The results have shown the effect of silicon content and temperature of metal on the content of boron in steel. It has been shown that an extract of the metal by slag, containing 4.3 % B₂O₃ , is accompanied by boron reduction. The primary reductant of boron is silicon, whose content in the metal after the experiment is reduced by 15 – 22 %. Thus, the steel sample with high concentration of silicon contains greater amount of boron. Recovery rate of boron ranges from 5.8 to 6.9 %, it is essentially correlated with the results of thermodynamic mod­eling. The concentration of boron in the metal can be controlled by changing temperature of process and content of silicon in the steel. The research results can be used in the development of the process technology of direct steel microalloying with boron.

The paper describes the conducted physical-chemical certification of silicone carbide, obtained from fine-grained charge of two kinds, which contains microsilica formed at the production of silicon and high-silicon ferrosilicium, as well as semicoke from brown coal of Beresovskii deposit of Kansk-Achinsk basin. Microsilca of both kinds contains 93.41 – 95.33 % and 91.72 – 93.00 %, 63 % of SiO₂ ; 1.96 – 3.28 % and 0.56 – 1.18 % of С_своб. ; 0.30 – 0.34 % and 0.18 – 0.20 % of Si_своб. ; 1.25 – 1.45 % and 1.38 – 2.32 % of (CaO + Fe₂O3 + MnO). Microsilica has a specific surface of 21 000 – 24 000 m²/kg and is inclined to aggregation with the formation of spherical units with the size of 200 – 800 nm. The units consist of spherical particles with a dimensional diapason from 30 to 100 nm. Brown-coal semicoke contains 94.05 % of carbon; 9.2 % of ash; 0.2 % of sulfur; 0.007 % of phosphorus and has a specific surface of 264 000 kg/m². Phase and chemical compositions of silicone carbide, its specific surface, the size and the form of carbide particles have been studied. It has been established that in both cases predominate phase is silicon carbide of a cubical structure (β-SiC), but an accompanied one is a glassy phase, formed with lime silicate, magnesium and iron. At carburizing of charge, containing microsilca of the production of ferrosilicium, α-iron accompanies to silicon carbide. At the synthesis temperature of 1923 and 1973 K and the duration of 50 and 90 minutes polymorthic transformation of β-SiC into α-SiC_II occurs. The content of silicon carbide in the products of carbonization is 82,52 – 84,90 %. The authors of the work have established the viability and optimal conditions of chemical enrichment of silicon carbide: influence of hydrochloric acid with the concentration of not less than 35 % at the temperature of 353 K, ratio of Т:Ж = 1:2, durability of 3 hours. The indexes of chemical enrichment have been defined: the content of silicon carbide in the products of enrichment is 90.42 – 91.10 %, removal of impurities of metal and iron oxides of 87 – 95 %. Silicon carbide appears as micropowder with the particles of wrong form with the dimensional range of 0.2 – 1.0 um with the specific surface of 8000 – 9000 m²/kg.

Binary liquid-metal thermodynamic systems with strong negative deviations from Raoult’s law can be satisfactorily described within the model of ideal associated solutions when three types of associates are participating: Ар В, АВ and АВq , where А and В are the solution components; р and q are stoichiometric coefficients numerically equal to 2, 3 or 4. More complex associates, Ар Вq in particular, do not form in the solution. In these conditions, according to the rule of phases of associated solutions, the number of associate types in each point of a binary solution must not be greater than two. Since Ар В and АВq associates interact chemically producing the АВ associate, a subsystem containing only Ар В and АВ associates and a subsystem containing only АВ and АВq associates can be conventionally formed out of the complete thermodynamic system.This method allows determining and expressing concentrations and thermodynamic properties of the assumed associates in an explicit analytical form in each subsystem. The obtained results, however, are normally checked by the numerical solution of a system of initial equations with set calculated thermodynamic parameters. Two separate calculated solutions at the junction of subsystems are “jointed” using the previously proposed special functions imitating diffusive leveling of the associate concentration difference in this nonequilibrium zone. Identification of real solution associates with this method can be considered as valid and not requiring any adjustable parameters if calculated free energies of the associates are close to the reference values of free energies of the respective intermetallides. For example, when experimental data of component activities at 1600 °C were analyzed in the Ni – Al system for the identified associates Ni₃Al, NiAl and, the free formation energies were found to be 129.6, 93.1 and 124.2 kJ/mole, respectively. These values are close to the average formation energy values of the respective intermetallides specified in the modern data bases, i.e. 130.1, 92.5 and 126.0 kJ/mole, respectively. Similar analyses were also performed for seven other binary systems with aluminum, including systems containing one or two types of as sociates. The absolute error of approximation of activity isotherms of solution components for this method was 0.001 – 0.035.

The new construction materials with high technological and performance characteristics, which cannot be achieved by traditional methods, are required to create modern mechanical equipment. Prospects for the development of technologies of steels form changing are largely related to the use of external radiation, in particular powerful current pulses generated by the pulse generators of powerful unipolar current amplitude up to 10 – 15 kA, frequency reproduction up to 400 Hz and pulse duration of 100 microseconds. The disadvantages of such generators, preventing their widespread use in the industry are low efficiency and significant power consumption of the AC, as well as the inability to control the power parameters. The article presents description of the powerful generator of unipolar pulses having the charger connected to power capacitors and the thyristor switch, discharging the capacitors to the low ohm load. In order to reduce the main power, the charge exchange device on the base of thyristor connected antiparallelly in thyristor switch is introduced in the scheme. To realize the possibility of pulse amplitude control and increase in its capacity two irreversible thyristor transformers are used in charger instead of an unregulated direct current source. These thyristor transformers are switched on in series and in unidirectional way. They permit to obtain the regulated voltage at power capacitors. In order to optimize the capacitor charging process a two-circuit system of subordinate regulation of pulse generator parameters with external voltage control circuit and internal control – current capacitor charge. The model of the suggested generator is implemented in the “Matlab, Simulink” medium. This model is adequate to the real pulse generator used in SibSIU for investigation of electrostimulated plastic deformation of metals and alloys. The developed model permitted to improve the technical parameters and device operation regimes. The considerable mains power decreases as well as possibility of capacitor charge voltage control up to 600 V in the range of pulse repetition frequency of 400 Hz are the advantages of updated generator in comparison with the analogues. The generator can be used in industry, in particular, at rolling production for hard deformed steel wire drawing.

The mathematical problem definition considering dependence of heat transfer coefficient on surface temperature in case of heating (chilling) of bodies of the correct geometrical form in the form of an unrestricted plate, cylinder or sphere, in case of free convection in unrestricted amount was for the first time written down, thereby making the task of heat conductivity nonlinear. The decision for model of thermally thin body was received. The calculation method for the surface temperatures at initial stage was developed. On the basis of the integrated linearizing transformations the engineering method of fields of temperatures and axial thermal tension in a quasistationary stage of heating (chilling) of bodies of the correct geometrical form was developed for the case of the heat exchange coefficient depending on surface temperature under the sedate law according to the mode of free convection: laminar, transitional or turbulent. Verification of decisions on model of fixed heat transfer coefficient have shown that the error of decisions is acceptable for engineering calculations, and not accounting of the dependence of heat transfer coefficient on temperature can result in big inaccuracies. Formulas for calculation of axial thermal tension are given for any point of the body: on a surface and in the center.