The analysis of technological processes of smelting and casting of cylindrical bars from Inconel 718 alloy, obtained in a vacuum induction furnace at PJSC “Ruspolimet”, was performed. The existing technology does not ensure the production of a sound bar of the required quality due to the presence of porosity in the axial zone, and also due to liquation at the macro level of elements such as chromium, nickel, niobium. The results have shown the need to adjust the parameters of casting and solidification of bars from the Inconel 718 alloy. The task to get high-quality sound bar was set without changing the main technical parameters of production, namely: type of furnace – vacuum induction furnace with capacity of 3 tons; material of the furnace lining – ceramics based on aluminum oxide Al₂O₃ ; type of the casting mold – cylindrical mold for bar diameter of410 mm; diameter of crystallizer for vacuum-arc remelting –450 mm. With the use of the Thermo-Calc program (version 2017a), the solidus temperatures for the equilibrium solidification process and for the non-equilibrium process were clarified, which were 1211 °С and 1091 °С, respectively. Based on the results obtained, the casting speed (SCM LP) system corrects casting speed by reducing the diameter of the casting nozzle from 32 to28 mm and casting temperature by reducing it from 1470 to1460 °C. According to the corrected technology, a batch of bars has been smelted. From the bar of the first batch, transverse templates were selected to determine the chemical composition and longitudinal temp lates for metallographic analysis. Metallographic studies have been carried out that suggest a decrease in porosity of axial zone of the bar and a decrease in phase separation at the macro level. Based on the results obtained, the authors proposed to introduce approp riate changes in casting technology. It is shown that computer modeling of metallurgical processes of metal casting and crystallization allows developing a technology of obtaining a high-quality bar already at the first redistribution, while avoiding appearance of products that do not meet customer requirements.

In this paper, the development features of a single free jet of hightemperature nitrogen interacting with a flat surface were studied. Calculation of the heat exchange process during heating by the attacking jets is very difficult to implement analytically due to complexity of the gas-dynamic processes occurring both in a single jet and in a system of jets interacting with the metal. The computational difficulties are aggravated by the fact that when interacting with the surface the jet as such disappears. The flat (fan) flow interacts with the surface: form, aerodynamic properties and thermal state of the flow strongly differ from those of the original jet. The studies were conducted on the basis of numerical simulation in the FloEFD software and computing complex for multiphysical simulation based on solution of the equations of gas dynamics and heat transfer. The solved system of equations consisted of Navier-Stokes equations, equations of energy and continuity and was supplemented by k – ε turbulence model. A three-dimensional model was developed for simulation, the necessary properties, initial and boundary conditions were specified. In the study of aerodynamics of a single high-temperature jet interacting with the surface, the main defining values were: nitrogen flow rate from the nozzle U0 , nitrogen temperature T, internal diameter of the nozzle d0 , distance from the nozzle section to the surface h, distance from the critical point (point of intersection of the jet axis with the surface) along the flow radius r. Data on the gas velocity decrease as the jet develops due to the loss of initial energy to engage the motionless surrounding gas in motion, is presented. The studies have shown that increase in the initial velocity of gas outflow brings the area of higher velocities closer to the surface both in the jet itself and in the fan jet. This factor contributes to heat transfer intensification. In addition, high speeds increase the total thickness of the fan flow and reduce the thickness of hydrodynamic boundary layer, which increases with distance from the critical point.

A comparative assessment of strenuous state of the anvils with and without channels has been carried out for the installation of combined continuous casting and deformation process in the production of steel sheets for welded pipes. The conditions of operation and loading of the anvils of combined continuous casting and deformation process are described. The design of anvil with channels for water cooling and the nature of its loading are given. Using the algorithm for solving problems in the elasticity theory by finite element method, the laws governing the distribution of axial stresses in anvils from the slab reduction force are determined. Effect of the channels for anvils cooling with water on the magnitude and nature of stresses distribution in them from the stress of the slab reduction was estimated. The calculation results of temperature fields and axial and equivalent thermoelastic stresses in anvils with channels are presented for the production process of steel sheets for welded pipes in a combined continuous casting and deformation unit. The article considers regularities of total stresses distribution in anvils with channels. To assess the effect of anvils structure on their stress state, regularities of distribution of thermoelastic and total stresses in strands without channels have been determined. The graph of dependence of thermoelastic stresses in the anvil on temperature of its contact surface is given. Recommendations for choosing the material of the fighters are given. The advantages and disadvantages of the anvils with channels for the unit for combined continuous casting and deformation are described. The parameters of such a pilot installation are presented. The authors also describe the results of an experimental study of the parameters of a combined process at the manufacture installation for continuous casting and deformation of JSC Ural Pipe Plant.

Granulated blast furnace slag is steadily used in large quantities in production of cements, in road construction, agriculture and in other areas of engineering and technology. Peculiarity of its production process is active interaction of molten metallurgical slag with cooling liquid. Simultaneously and instantly, slag solidifies and the mass of the latter breaks up in the atmosphere of hot steam into small particles due to critical stresses occurring. The problem is that during granulation of slags, usually containing sulfur, large amount of harmful substances (sulfur oxide and hydrogen sulfde) is released into the atmosphere. Its concentration at work sites - sites of granulation many times exceeds the MPC. To combat this phenomenon, finely dispersed, expensive lime or limestone is introduced into the composition of cooling liquid. This is associated with high costs for the construction of crushing, grinding and dust treatment equipment. In addition, placement of such equipment is hampered by the lack of free space in the blast furnaces. In this work, it is shown that lime and limestone can be replaced by fine red mud (RM), a waste from the production of alumina from bauxite. This material also has properties of absorption of sulfur compounds from the gas phase. The problem of its processing is also an urgent task. At present, RM is located in sludge storage facilities that are harmful to environment, and destruction of the enclosing dam leads to an environmental catastrophe (Hungary, 2010). This article presents the results of study of RM use. Sorption properties of RM of 6 plants were studied under laboratory conditions. The samples of granulated slag obtained in the process of interaction with RM were investigated. Laboratory and industrial tests were conducted. It was found that with its help, concentration of sulfur gases at granulation work sites can be reduced by twice. It is important that the new granulated slag, called “sludge-slag” in this case, is not inferior to the usual one by its basic technological properties.

Based on the analysis of the literature and production data, it is shown that the wear resistance of steel grinding balls, which are the main grinding medium for crushing various types of raw materials in the drum type mills, is determined not only by hardness of the surface layer, but also by the quality of their macro- and microstructure. At the same time, there is a complex nature of dependences of the balls impact resistance on the above mentioned parameters with their simultaneous impact, which determines the relevance of research in this direction. Series of experimental studies was carried out in order to obtain scientifically based dependencies of impact resistance of grinding balls on the quality of their macro- and microstructure. The grinding balls with a diameter of40 mm,50 mmand60 mmproduced by OJSC “EVRAZ ZSMK” (Novokuznetsk) and by JSC “Industrial Solutions” (Nizhny Tagil) were used. The research was carried out by metallographic, durometric and fractographic methods of analysis; tests of grinding balls on the impact resistance were performed on the impact drop machine. According to the results of metallographic studies it was determined that the volume-hardened balls are characterized by a three zone structure. The surface hardened layer with a depth from 1.9 to7.4 mmis martensite. The transition zone with thickness from 1.0 to1.7 mmhas a structure martensite + troostite. The central zone occupies the entire remaining volume of the ball and has several varieties of microstructure: ferrite + perlite, martensite + troostite + ferrite, martensite + troostite. On the basis of generalization of the obtained experimental data, it was established that at surface hardness of balls within 42 – 52 HRC the quality of macrostructure (presence of flakes) is the parameter determining impact resistance. For balls with high surface hardness (57 – 61 HRC) the most significant impact on impact resistance is provided by non-uniform microstructure of metal, which causes a significant difference in hardness across the balls crosssection.

Base characteristics of ferritic-martensitic heat resisting steels with 12 % of chrome are parameters of their strength and creep resistance at temperatures of 600 – 750 °С. Steel 16Cr12MoWSiVNbB (EP-823) is considered as the basic material for manufacturing environments fuel rods (TVEL) of a developed reactor with natural safety of BRESTtype. In the literature, there are data about its mechanical characteristics for tensile tests in a range of temperatures of 20 – 750 °С and the limited characteristics of rupture strength. Data on its creep velocity is absent. Laws of creep of steel EP-823 were investigated on metal of three heats with weight of 3 kg. The compression tests at air were applied for cylindrical samples of 5 ÷ 6 mmat temperatures of 600 – 760 °С and stresses of 70 – 310 MPa. The base of compression tests did not exceed 11 hours. The structure after quenching and tempering consisted of tempered martensite and 6 – 12 vol. % of delta-ferrite, the grain size was less 20 μm. It is shown, that the description of creep tests results in double logarithmic (log (σ) – log (έ)) coordinates provides the best concurrence of results of approximation and experiment, than in half-logarithmic (σ – log (έ)). The analysis of parametrical dependences on Hollomon’s P_S = (T/1000)[C_S – log (έ) and to Larsen-Miller’s P_E = (T/1000)[С_E – log (σ)] has allowed to find the equations for creep velocity for the set pressure level of 100 – 220 MPa in the form of log (έ) = –19,355 + 9,17 (T/1000) log (σ) and ultimate strength of creep under the set admissions for creep velocity of 0,01 – 1 %/hour in the form of log (σ) = 4,304 – – 0,109 (T/1000) [20 – log (έ)]. Calculations of ultimate strength of creep and creep velocity on pair models and models of Hollomon (Larsen-Miller) give close results, but the preference should be given the second ones as these models consider all three varied factors. Data of control tests under the scheme of a tensile in the same conditions are cited. It is shown, that between results of tests on compression and on tensile at definition of durability characteristics, there is the linear dependence expressed by the equation σ_0.2 at compression = 1.3σ_0.2 at tensile. At the analysis of creep it has been established, that creep velocity for steel of one grade (09Cr12W3NbB) and for one heat at different type of loading (tensile or compression) have similar values while creep velocities for steel of one grade (EP-823), but of different heats even at one type of loading – compression, can differ substantially.

The processing of friable materials used in metallurgical industry for production of definite size classes requires operation of crushing machines, including single-roll machines. Parameters of crushing process are degree and efficiency of crushing. The crushing degree is estimated by the ratio of dimensions of the initial crushing and resulting pieces and depends on the size of gap between the roll and the fixed jaw. Crushing efficiency is determined by mass of material crushed by consumed electric energy unit, and depends mainly on strength of crushed material. In order to reduce energy consumption needed for crushing, a single-roll crusher was developed at Siberian State Industrial University with forced feeding of crushing piece into the fracture zone due to the locker located on the roll. Forces of technological resistance appearing during machine operation are the main initial values for machine drive power and structural elements strength testing, thus, the operation power analysis is an integral stage in the design of any machine, including a crushing one. In the present work, forces acting on a crushing piece from roll side and fixed jaw in vertical and horizontal planes are identified. Based on the results obtained, it was determined that internal compressive forces acting on piece of crushing material cause action of normal compressive stresses in a piece, as well as an internal torque effect, which causes shearing stresses action, i.e. a complex stress state is generated in a fractioned piece with simultaneous action of normal and shearing stresses, under which action a fractioning piece is destroyed. Thus reduction in energy consumption for crushing is achieved, with all other conditions being equal. It reduces energy consumption of a single-roll crusher with forced feeding of material into the crushing zone.

Cutting with parallel blades cutters consists of three periods: blades ridging in metal; cutting; chipping (separation). Maximum force is required at the end of the ridging period and at the beginning of cutting. Since one of the blades is stationary, the second blade in cutting process has to go deep into the entire thickness of metal to cut the billet. For example, if thickness of metal is20 mm, then the upper blade needs to pass20 mmfor its cutting. If you make both blades moving towards each other, cutting effort will be less. In this case, each blade cutting20 mmof metal will pass 10mm. In order not to make mechanism of cutter with two movable blades too complicated, it is important to ensure its mobility from one drive. So, there acute the issue of arrangement possibility of blades moving towards each other with guaranteed strength of the units, transmitting effort on the blades. Kinematic scheme of cutters with blades moving parallel to each other in a vertical plane is proposed. Advantages of the proposed cutters design are the following: counter movement of blades requires less effort to cut the billet; force from each blade is distributed to two connecting rods, reducing load on each of them; since blades move towards each other, the main cutting force is distributed along the units of the mechanism and is transmitted to the engine, which reduces load on the frame and foundation when cutting; when blades move towards each other, metal separation occurs faster, it allows to concentrate maximal force during cutting with minimal load on the engine; the cut part of the billet does not fall below the roller bed at the end of cutting, so installation of the lower movable table is not required. Mobility of the proposed mechanism is determined by P.L. Chebyshev formula with its value = 1. Kinematic analysis of blades is carried out using a special method, which is in using point of connecting rods intersection.

The strain parameters instability causes variable axial stress during the drawing process. Contact friction specification varies in the shortest time and depends on many factors: homogeneity physico-mechanical properties of the processed material along the length of the pulled billet, quality of technological lubrication, stability of tension force of the billet at the entrance of deformation center and cooling intensity of the fiber, suction drums, washers, rollers, etc. To estimate the effect of friction coefficient on stability of drawing force (stress), first derivative with respect to friction coefficient in drawing equation is used. The first derivative dependence on drawing coefficient is constructed for different hardening models and deformation parameters. Action of anti-tension was investigated when drawing on stressed state of a circular continuous profile. Studies have been carried out for simulation models of hardening. In the course of study, it was proved that it is possible to estimate instability of stressed state by the first derivative with respect to magnitude, depending on friction coefficient of the equation that determines drawing stress. For different deformation parameters, the first derivative with respect to friction coefficient is calculated for the equation determining axial drawing stress. A decrease in magnitude of the derivative is shown with an increase in anti-tension, which indicates expediency of drawing with antitension to stabilize drawing force and to reduce fatigue wear of dies working surface. Calculations were performed for different values of friction coefficient for drawing under the conditions of presence and absence of drawing cylinder and slope angle of drawing cone to drawing axis, mechanical properties of the billet for drawing, and for various coefficients of its hardening. The stabilizing effect of drawing cylinder of dies on drawing stresses with an increased friction coefficient is shown. Instability of drawing stress from deviation of nominal value of friction coefficient depends on values of other strain parameters. In conditions of drawing cylinder presence and small amount of deformation in drawing path and smaller initial friction coefficient, change in its magnitude has a greater effect on stability of the stressed state. Increase in drawing stress stability positively affects quality of wire, operational stability of units and drawing-line elements, for example, due to decrease in fatigue wear of die working surfaces, drawing drums, bypass and straightening rollers. Drawing with anti-tension and the use of special drawing tools stabilize stress state in deformation zone.

The article presents and describes Cohen’s class time-frequency distributions which are expedient to use as a mathematical tool that allows to create a convenient – in terms of information content and semantic clarity – visual-graphical representation of the opera ting modes of various technological processes including processes of ferrous metallurgy. It was noted that a controlling process is usually implemented without simultaneous visual monitoring of each scalar (one-dimensional) coordinate that is under control, but the presence of such monitoring is an important condition for the computer-aided controlling of the dynamics of non-stationary technological processes. To eliminate this drawback, it was proposed to perform synchronous monitoring using the multidimensional Cohen’s class time-frequency distributions, when each measurement scalar signal is specifically represented through one of these distributions, for example, the Wigner-Ville distribution. An expression is given for the generalized distribution of Cohen’s class with a distribution kernel and an ambiguity function. This function allows receiving distributions of various types from the maternal function. The most typical representatives of time-frequency distributions forming this class are given with their available  kernels. The possibility of appearance of interference elements, which make it difficult to identify the controlled modes, on a signal distribution map is proved. Case of the formation of virtual elements within the Wigner-Ville distribution representing a two-component one-dimensional signal is considered. Te conditions are explained for the emergence of parasitic elements on the distribution map, obtained, for example, during realizing the process of multi-component feeding the bulk blast furnace charge materials in the production of sintering mixture. An analytical expression is obtained for the Wigner distribution, which displays a multi-component scalar signal and contains the information (useful) and virtual (parasitic) parts of the time-frequency distribution. A link between the number of bulk material feeders available in the feeding devices unit and the number of parasitic (virtual) elements in the Wigner distribution was determined. Using the dosing process as an example, the effect of the noise components propagation in the Wigner distribution is demonstrated. An example is given to illustrate the penetration of noise into the Wigner distribution and appearance of the virtual concentration in it when displaying a signal waveform with a noisy pause and two sections with different frequencies. An expression for the Wigner distribution in the form of a comb function is obtained. The conclusion was made about the parameters of the distribution periodicity and the required sampling frequency of measurement signals.