The paper presents the results of metallographic studies of stresscorrosion defects (SCC defects) detected on the output gas pipeline of the compressor station. The diagnostics statistics of defects in such pipelines and the data on the effectiveness evaluation of various diagnostic tools during the diagnosis of SCC are given. A presumptive steel grade corresponding to the pipeline metal was identified. The species and morphology of cracks are described. Their character of development is defined. To detect traces of the influence of metallurgical impurities and the external environment on the defects development, a spectrometry of corrosion products and base metal was made. The authors have made the maps of elements distribution over the sample controlled surface. The absence of influence of nonmetallic sulphide inclusions on the development of metal destruction in this is described for the particular case of SCC. It is shown that the sulfur content in corrosion products does not exceed the sulfur content in the sample metal. In some samples, reduced sulfur content can be observed, with the exception of local sites with nonmetallic sulphide inclusions. Electronic images were obtained, which show that these nonmetallic inclusions (in this case) are not sources of cracking development. The results of cyclic tests of samples cut from the pipeline and containing cracks are given. The choice of the cyclic test mode was carried out in accordance with the analysis of the compressor station operating mode for the current year of operation. According to the data received, pipe materials with defects at their initial stage of development have shown considerable durability under test loads. The samples with cracks have withstood from 1.6·106 to 7.5·106 loading cycles under conditions of cyclic transverse bending in the same test plane in the absence of a corrosive medium. In a real gas pipeline under normal operation conditions, the number of such cycles does not exceed 120 – 200 per year, therefore, it can be concluded that the pipeline with defects in their initial stage of development has a significant residual life, provided that its metal wall is reliably protected from effects of corrosive environment.

The study results of introduction of barium-strontium carbonatite of various fractional composition into flux based on silicomanganese production slag are presented. The principal possibility of using their mixtures for depositing and welding of low-alloy steels is shown, while the use of barium-strontium carbonatite makes it possible to reduce contamination of weld metal with nonmetallic inclusions. In series of experiments in laboratory conditions, various compositions of welding fluxes were made and investigated. As components, barium-strontium modifier BSC produced by “NPK Metallotechnoprom” LC under TU 1717-001-75073896-2005 was used, wt. %: 13.0 – 19.0 % BaO; 3,5 – 7,5 % SrO; 17.5 – 25.5 % CaO; 19.8 – 29.8 % SiO2 ; 0.7 – 1.1 % MgO; 2.5 – 3.5 % K2O; 1.0 – 2.0 % Na2O; 1.5 – 6.5 % Fe2O3 ; 0 to 0.4 % MnO; 1.9 – 3.9 % of Al2O3 ; 0.7 – 1.1 % TiO2 ; 16.0 – 20.0 % CO2 as well as silicomanganese slag produced by JSC “EVRAZ – West-Siberian Metallurgical Combine”, wt. %: 6.91 – 9.62 % Al2O3 ; 22.85 – 31.70 % CaO; 46.46 – 48.16 % SiO2 ; 0.27 – 0.81 % FeO; 6.48 – 7.92 % MgO; 8.01 – 8.43 % MnO; 0.28 – 0.76 % F; 0.26 – 0.36 % Na2O; up to 0,62 % K2O; 0.15 – 0.17 % S; 0.01 % P. Basis of the flux is silicomanganese production slag, into which a flux additive was introduced. Flux additive was produced in two ways. The first one: by mixing barium-strontium modifier with liquid glass in a ratio of 75 and 35 %, respectively. The second variant is as follows: dust of strontium-barium modifier of fraction less than 0.2 mm was used as a flux additive. The technology of flux-additive manufacturing is described. Welding of rollers was carried out using ASAW-1250 welding tractor. Regimes of surfacing were worked out. The chemical compositions of fluxes, slag crusts, flux and weld metal were determined. Metallographic studies of metal were performed. The results of analysis for presence of nonmetallic inclusions in weld zone were carried out in accordance with GOST 1778 – 70. Studies indicate a decrease in contamination of weld metal by silicates that are not deformed and absence of brittle silicates. 

The results of composition-viscosity plotting for slag of the CaO – SiO2 – B2O3 system containing 15 % of Al2O3 and 8 % of MgO using simplex lattice method are given in this paper. It allows obtaining mathematical models describing property dependence on composition as a continuous function. The study was subjected to a fixed area in a form of local simplex represented by two CaO – SiO2 – B2O3 concentration triangles. The experiment was planned in pseudo-component coordinates. To describe dependence of slag viscosity on its composition, a mathematical model of polynomial of the third degree was chosen. In experiment planning matrix, slag compositions are given in pseudo-components and original components coordinates. Slags corresponding to studied local simplex vertex composition were melted in graphite crucibles from pre-heated oxides of ChDA brand. Composition of slag, corresponding to the points of local simplex plan, was obtained by counter-mixing of simplex vertex slag. In experiments, molybdenum crucibles were used to measure slags viscosity. Measurements were carried out using an electric vibrational viscometer in an argon flow with continuous cooling of melt from homogeneous-liquid to solid state. The results of generalization of mathematical modeling and graphical representation presented in form of compositionproperty
diagrams made it possible to quantify effect of slag basicity and B2O3 content on viscosity of resulting oxide system. The slag of CaO – SiO2 – B2O3 oxide system, containing 15 % of Al2O3 and 8 % of MgO, is characterized by sufficiently low viscosity in temperature range of 1450 – 1500 °C. Viscosity of such slags increases significantly with temperatures decrease to 1400 °C. It has been established that slags with basicity of 2 to 5, containing 1 to 4 % of B2O3 , are characterized by high liquid mobility at constant concentrations of Al2O3 (15 %) and MgO (8 %), their viscosity in temperature range of 1450 – 1500 °C does not exceed 4 – 7 poise. Such slags have, as a rule, high refining properties and can be recommended for the formation on a ladle furnace installation.

Flow of liquid melt in the crystallizer is a little-studied process. Analytical solutions of melt flow in general case refer to complex mathematical problems, therefore numerical methods are used to model it. The purpose of this work is to use numerical method proposed by Professor V.I. Odinokov, based on finite-difference representation of the initial system of equations. This method has been successfully used in mechanics of continuous media, in foundry industry in mathematical modeling of strained deformed state of shell molds on investment models,
as well as in other technological works, which indicates its universality. In the present study, the object of research is hydrodynamic flows of liquid metal during steel casting into a rectangular section mold when fed from a submerged nozzle with eccentric holes, and the result is a spatial mathematical model describing the flows of liquid metal in the crystallizer. To simulate the processes occurring in the crystallizer, the software complex “Odyssey” was used. The theoretical calculation is based on fundamental equations of hydrodynamics and approved numerical
method. Solution of differential equations system formulated
in the work was carried out numerically. Investigated area was divided into elements of finite dimensions, for each element the resulting system of equations was written in the difference form. The result of the solution is velocity field of metal flow in crystallizer volume. To solve the system of algebraic equations obtained, a numerical scheme and a calculation algorithm were developed. Based on developed numerical scheme and algorithm, a computation program was compiled in Fortran-4. Mathematical model makes it possible to vary geometric dimensions of the crystallizer and cross-section of metal exit openings from the immersion nozzle, and it can also help to understand the flow pattern of the cast metal that affects heat dissipation of crystallizer walls and to find the optimal parameters for liquid metal outlet from the gravy glass at various casting modes. As an example it is given calculation of steel casting into a rectangular mold with a height of 100 cm and a section of 2000×40 (cm) in plan. Casting was carried out from immersion nozzle eccentrically in both sides in a horizontal plane. The calculation results are presented in graphical form. The movement of liquid metal flows is shown, their magnitudes and intensity are determined. 

The system for electrostimulated drawing parameters control (temperature in deformation zone and drawing force) is considered, which forms a control signal to generator of high power current pulses. Its principle is based on periodic discharge of pre-charged capacitor to low-resistance load. To provide possibility of adjusting pulse amplitude and increasing its power, two non-reversible, serially and unidirectionally connected thyristor converters are used, instead of unregulated DC power source in charger, that allow obtaining adjustable voltage on power capacitors. In order to optimize capacitor charging process, two-circuit system of subordinate parameter control was carried out with an external voltage regulation loop and an internal circuit regulating charging current of the capacitors. Due to high speed of transient processes at electrostimulated drawing (a high degree of temperature rise in deformation zone due to considerable current pulse value up to 10 kA and its reproduction frequency up to 400 Hz), manual control is almost impossible. In order to increase reliability and quality of process of electrostimulated drawing using high power current pulse generator, an automatic control system for electrostimulated drawing
process (EDACS) is implemented. This system contains a single-loop system for adjusting the drawing force, as well as delayed temperature feedback in deformation zone. Dependences of change in drawing force and temperature on frequency of reproduction of pulses were obtained from the results of laboratory studies and calculations applying known and original techniques. For analysis of operating modes for electrostimulated drawing using automatic control system, the EDACS model was implemented in MATLAB-Simulink environment. The model is adequate to real parameters obtained in electroplastic effect investigations. The developed model allowed improvement of technical characteristics and operating modes of the system. Functional chart, model of system in MATLAB-Simulink environment, oscillograms of transient processes are considered. A singleloop automatic control system of drawing force with flexible temperature feedback in deformation zone allows optimization of operation modes as well as increase in reliability of electrostimulated drawing process. The system may be recommended for the research of electrostimulated deformation processes, it may also by introduced in production at wire drawing. 

The reasons for the occurrence of vibrations in engineering constructions and their effect on the operability of mechanisms are considered It is determined that one of the main sources of vibration of machine elements are plain bearings, in which the shaft is located in the hollow bar (liver) with a gap, there is a struck at the selection of it. The principle of vibration protection systems is considered, the main element of which is the elastic element - shock absorber. The influence of the rigidity of the elastic element on the performance of sliding bearings is analyzed. The design of an elastic pneumatic element of increased stiffness, made in the form of a cylinder with limited radial deformation, is given. It is shown that the ability of such an element to center the shaft relative to the geometric axis of the support under the action of a radial load is provided by the appearance of a difference in contact area between the outer surface of the bearing housing and the surface of the elastic cylinder. A technique is developed for calculating the increment of the contact area of an elastic element, made in the form of a pneumatic cylinder with limited radial deformation, with a surface through which the external load is transmitted at specified support parameters: the length of the cylinder and the amount of excess gas pressure inside the cylinder. It is believed that the shaft is in the bearing without a gap, and the shell forming the cylinder is inextensible. It is established that the deformation and rigidity of an elastic pneumatic cylinder with limited radial deformation depend on its length and the magnitude of the excess pressure inside the cavity. The obtained mathematical dependencies allow defining and setting parameters of an elastic pneumatic element made in the form of a cylinder with limited radial deformation (cylinder length and the value of excess gas pressure inside the cylinder) depending on operating conditions of the sliding bearing.

Traditional processes of thermochemical treatment of steel have a longer duration, so there are proposed the new methods of intensification of diffusion saturation with high-energy impacts on the material surface. In the process of micro-arc alloying the steel product is immersed in a container filled with powder of coal, and is heated by passing electric current. In a powder environment, microdischarges are formed, which are concentrated around the product and create an area of gas discharge with the formation of a carbonaceous gas environment, which enables carburizing of steel. The application of coating containing diffusant allows forming coating of a carbide type due to simultaneous carbon diffusion into alloying elements. The influence of micro-arc surface alloying of steel with vanadium on mechanical properties of diffusion coatings is studied, and the primary mechanism of steel hardening at microarc alloying is revealed. Cylindrical samples of 20 steel were used; the source diffusant was a powder of ferrovanadium. Current density on the sample surface was 0.3 A/cm2, total duration of the process was 3 min. The mechanical properties of coatings were evaluated by means of indentation using pyramidal indenter, at loads of 2.5 mN, 20 mN and 100mN. The diffusion layer with thickness of 170 – 180 μm consists of a base with hardness of 8 – 9 GPa, containing mild etching inclusions of up to 5 μm with microhardness of 21 – 25 GPa. The base of the layer represents an α-solid solution of vanadium in iron, and inclusions are carbides of VC0.863 type. By atomic force microscopy it was established, that the surface relief is defined by single, relatively large carbide particles with a size of up to 3 μm, and by plural nano-sized carbide particles, which act as  the strengthening phase, providing high microhardness of the coating. By method of indentation of the hardened layer cross section using different loads hardening effect of the carbide particles is proven. Estimation of possible mechanisms of hardening have shown that the greatest contribution to diffusion layer hardening is made by dispersion component significantly increasing the yield stress of α-solid solution of iron in comparison with the initial state, which is 38 times greater than the contribution of solid-solution hardening.

The interaction of hydrogen atoms with nanocrystalline palladium and nickel in the work was studied by the molecular dynamics method. The nanocrystalline structure of palladium and nickel was created in the model by crystallization from the liquid state at the presence of several specially introduced crystalline embryos. After solidification, the calculation blocks, in addition to the crystalline phase, contained grain boundaries and triple junctions of grain boundaries. The interactions of metal atoms with each other were described by the multi-particle Cleri-Rosato potential constructed in the framework of the tight-binding model. Morse potentials were used to describe the interactions of hydrogen atoms with metal atoms and with each other. The parameters of Morse potentials were calculated from the experimental data of the
absorption energy, the activation energy of the above-barrier diffusion of hydrogen in a metal (at normal and high temperatures), the binding energy with a vacancy, dilatation. According to the results obtained in the present work, at a high concentration of hydrogen (the concentration of 10% from the metal atoms was considered), the hydrogen atoms combine into aggregates, which are formed predominantly near the surface of the metal. The aggregates contained, as a rule, several dozen hydrogen atoms and had low diffusion activity. The binding energy of hydrogen atoms with these aggregates was greater than with the metal crystal lattice or grain boundaries in it. In palladium, hydrogen aggregates were formed farther from the surface than in nickel. Apparently, this is due not so much to the relatively low energy of hydrogen absorption by palladium (–0.1 eV) in comparison with nickel (0.16 eV), but rather to the difference in lattice parameters of the metals under consideration: 3.89 Å for Pd and 3.524 Å for Ni. For the same reason, conspicuously, hydrogen aggregates in a pure crystal lattice were more often observed in Pd than in Ni. In Ni, aggregates, as a rule, were formed in defect areas containing an excess free volume: near the free surface, in grain boundaries and in triple junctions.

Experimental studies of laser-irradiated layers in a magnetic field (MF) have shown a non-trivial morphology of the surface of handling zone of material in case of reflow. Twisting of a thin layer of liquid metal is observed, irradiated area is getting a crescent appearance, definitely strictly oriented in relation to magnetic flux. This is probably due to the effect of Righi-Leduc, as well as the action of Lorentz forces, which deflect the electrons flow. As a result, there is significant mixing of metal in the irradiation zone, chemical composition equalization, which positively affects the strength properties of the products. One of the important consequences of the MF-effect on the results of laser processing is the phenomenon of magnetostriction. In laser irradiation without MF slide lines were observed on the pre-polished surface patterns resulting from the emerging thermal and structural stresses. By analyzing the topography of irradiated surfaces using modern analysis techniques and computer image processing, it was established that irradiation in MF in conditions of magnetostriction decreases the stress level in irradiated areas and reduces the risk of cracking. The results of temperature measurements at the irradiated spot on cooling stage allow establishing that the cooling rate during laser processing in a MF is considerably higher than without the field. It affects the processes of phase and structural transformations. At laser heating in MF microheterogenic austenite is supercooled with great speed to temperatures of martensite transformation. After that its transformation begins, the sequence of which is determined by the level of local saturation, degree of deformation and is controlled by temperature. The first crystals of martensite are formed in the least saturated areas of austenite, and a very high speed (thousands or tens of thousands of °С/s) of the transformation process beginning γ → α prevents martensite self tempering, which partially can occur when the temperature decreases further due to transformation spread on the remaining volume of austenite, grabbing areas of different saturation. As a result, along with the “fresh-formed” martensite in the areas of laser quenching the martensite is formed, in which segregation of carbon or even ε-carbide may occur and residual austenite with high carbon intensity are formed. Released dispersed carbides contribute to obtaining a sufficiently high hardness values of metals irradiated in a MF.

Using local systems of automatic control of temperature and surplus pressure of heating in the working volume of flaming thermal furnace of chamber type, settings, as a rule, are selected separately without the account of their interconnection. At the same time in control of expense of fuel and air not only temperature but also pressure changes in the working chamber of furnace, that, in turn, is accompanied by change of gaseous exchange with a medium and renders substantial influence temperature in a working chamber. All this is accompanied by substantial excessive consumption of gaseous fuel, and, as a result, by the rise of costs of metal heat treatment. Using heating chart with the constant volume of products of burning in the furnaces of such type, the control of its heat power is in combining charges of different components of gaseous fuel at condition of providing of the given temperature in the working volume. According to the principle of Bellman dynamic programming, optimization of control for the cycle of metal heat treatment was provided by choice of the applied fuel which is optimal on a cost composition for every period of quantum. The present cost of fuel serves as the linear function of middle charges of its separate components in periods of quantum and finding of its minimum value for every discrete moment of time, presented as a decision of task of the linear programming. The determination algorithm for optimal values of charges of gaseous fuel separate components was worked out, as well as for the expense of surplus air, used as controlling influences for the automatic systems of adjusting of temperature and surplus pressure of heating medium in the working volume of furnaces. The functional cart of automatic control system is provided, which implementation allows not only optimization of heating technology by cost of separate fuel components, but also provision of the control autonomy of temperature and surplus pressure of heating medium in the working chamber of furnaces of chamber type by means of self-adjustment. In real-time control process is executed with optimization of cost of separate components of fuel self-adjustment of the system.

The article presents the results of modeling in a dynamic format 
of one of the most important parameters of any research object – the efficiency of its work. As the object of investigation, a blast furnace with a volume of 2014 m3 was chosen. The main parameters of the efficiency of this object are traditionally used daily productivity and specific consumption of coke; these two parameters were generalized in this paper. In this case, various algebraic signs of the influence of these parameters were taken into account in the generalized efficiency index. Taking into account the variation of each of these parameters at 3 levels, the number of levels of the generalized efficiency index was determined as 32 = 9, therefore it was rational to take a 9-point scale with the measuring scale of profitability from the efficient operation of the blast furnace. The two-dimensional array of primary data of the volume N = 177 was transformed into a 9×9 transitional matrix for processing of random transitions of the efficiency index from one state to another by the Markov chain method with discrete states and time. The set of parameters of the random process is calculated: for the long-term forecast – the stationary vector of state probabilities, the average time of recurrence (reversal) for each efficiency state, the evaluation of the blast furnace efficiency in points; for a short-term forecast – the first time of transition from each state to any other state, the step number for a “burst” of probability for each reliable state at the initial moment of time, and the components of the efficiency index are obtained. It was established that the average level of the analyzed efficiency of the blast furnace (daily output 3702 tons and specific coke consumption 470 kg/ton) is achieved mainly due to short-term transitions of low-efficiency states to high-efficiency states and vice versa. The transfer of the system to more efficient and prolonged conditions is possible, and as practice has shown on the same blast furnace after repair works to eliminate the distortion of the furnace profile, the daily productivity has increased to 5048 tons with a specific coke consumption of 445 kg/t, but the structure of the transition matrix and the calculated indicators of the Markov chain have fundamentally changed in the direction of increasing the probabilities of stay and transitions of the system in more efficient states. The use of the Markov chain method with discrete states and time makes it possible to estimate the probable value of the change in the parameters of the operation of a blast furnace in a given time interval with constant levels of parameters characterizing the conditions of its operation.

Thermodynamic analysis of the effect of silicon on the solubility of oxygen in Fe – Co – Cr melts has been carried out at 1873 K. Silicon has a sufficiently high deoxidizing ability in Fe – Co – Cr melts. Silicon at low contents practically does not affect the concentration of oxygen in the melt, which is determined by the chromium content. With a higher content of silicon after changing the mechanism of interaction process of chromium and silicon with oxygen, when silicon already determines the solubility of oxygen in the melt, the oxygen concentration decreases.