The increased interest in cold agglomeration in recent years has been largely due to the successful experience in operating briquette lines based on stiff vacuum extrusion (SVE). The high performance of SVE extruders and the satisfactory metallurgical properties of extrusion briquettes obtained this way (brex) make it possible to consider this cold agglomeration technology as promising. SVE extruders allow efficient briquetting of the materials with moisture contents values in the range of 12 – 16 % and compacting pressure of 3.5 – 4.5 MPa, leading to the possibility of achieving high values of mechanical strength of raw briquettes and eliminates the need for drying briquetted charge and heat treatment of the green briquettes. The growing scale of practical use of extruders in the steel industry necessitated the development of simple and effective methods for determining their operating parameters. The briquetted mass is a moistened plastic mass, driven by the blades of a rotating auger and squeezed out further through the holes in the extruder die in the form of elongated briquettes, repeating in cross section the shape of the hole. In application to the optimization problems of extrusion briquette technology, the exact solution of the Navier–Stokes equations for a viscous incompressible medium shifted between coaxial cylinders along the common axis of symmetry and twisted around it by longitudinal displacement and axial rotation of the inner cylinder is given, respectively, under sticking conditions and given longitudinal pressure drop. In particular, it was found that the speed of transportation of the mixed mass cannot exceed the speed delivered by the supplied pressure, and the formula of the latter is transferred to the compressible medium as a special viscosity integral for a viscoplastic medium, where it serves as a generalization of known exact solutions. A similar solution for a compressible medium is being sought. The obtained analytical dependencies can be used to calculate the parameters of industrial briquette extruders operating in both the stiff extrusion mode and the semi-stiff and soft extrusion mode, differing in the moisture values of the briquetted mass and the values of the applied pressure.

One of the ways to improve the technology of limestone roasting in shaft furnaces is associated with improvement of conditions of combustion with natural gas when burning it directly in the layer. To implement this technology, it is necessary to ensure the development of two parallel processes: preparatory, in which the initial gas-air mixture is formed and heated to the ignition temperature, and the main one, during which a layer of combustion of gaseous fuel occurs. At air-blast tuyere feed and at coaxial jet supply of gaseous fuel under increased pressure when there are gas permeable nozzles in the path, a more powerful gas flow (natural gas) flows out of the nozzle at high speed into the external environment. It creates conditions for air flow ejection. Inside the annular space between the streams, a combustion zone is formed, on the inner and outer side of which there are circulating vortices directed along the axis of the jet to the nozzle. It improves stability of the gas-air mixture ignition. The considerable range of turbulent jets (at elevated pressures of the gaseous medium), as well as the possibility of sufficient complete mixing in the boundary layer, opens up the possibility of forming a gas-air mixture of a given composition along the front of the flare process, the movement of gas jets. To ignite the gas flow in the layer, it is necessary to ensure its preheating at least to a temperature of 800 – 1050 °C using a heat source located near its entrance. Energy efficiency of this direction is confirmed by experimental studies on a shaft furnace with a working space with diameter of 3 m. According to the results of experimental sounding of the heated zone of a limestone shaft furnace (in the mode of layer burning of natural gas), regularities were established in changing the temperature field of the burning layer with the formation of maximum temperature of 1200 °C at a distance of 200 mm from the nozzle section. The depth of formation of the combustion zone was limited to the level of 110 mm with the spread of the region of high temperatures over a distance of up to 1000 mm. Technological possibility of forming a region of high temperatures of 1100 – 1600 °C with a length of the high-temperature zone up to 2000 mm was established.

Aside from electromagnetic stirring, casting with low superheat and intensive cooling of the strand in the upper range of secondary cooling zone, Mechanical Soft Reduction (MSR) has proved, above all, to be very effective in reducing segregation and axial porosity in continuously cast billet. Implementation of MSR technology in the production of continuously cast billets has a number of features that are due to their square shape. In this case, particularly promising is the use of blocks of segment design, so called pinch-roll segment. The presence in CCM line of MSR block of such design allows to implement a two-stage deformation scheme. The paper proposes a new two-stage scheme of MSR technology realizing the combined deformation on the basis of cobbing in vertical plane and shearing relative displacement of the faces at the first stage, and at the second stage – deformation on the basis of cobbing in vertical plane. This approach additionally helps to correct deformations of the profile cross section, namely the rhomboidity defect. We present the results of a comparative study using physical modeling methods to assess the contribution of additional shear relative displacement of faces in the horizontal plane to the overall efficiency of MSR technology of continuous casting. The use of a flat model in conjunction with the proposed form of deforming rolls and a combination of modeling materials allowed to achieve a good similarity in geometric criterion, as well as in the criterion of stress ratio equivalence arising at the interface of crystallization front. The obtained experimental data helps to develop ideas about the mechanisms of additional positive effect from the application of shear action. In particular, the deformation of metal surface and adjacent layers of the billet in the rolls with a special above-described profiling will improve their quality due to the occurrence of shear deformations intensifying the process of collapse of subcortical bubbles, “healing” of microcracks, etc. In turn, the artificial creation of torque effect in cross section of the billet will contribute to the occurrence of shear deformations in the crystallized “bridges” of axial liquid-solid region of the ingot, thereby intensifying the process of their destruction and improving the quality of the billet’s macrostructure.

Knowledge of the nature and behavior of forces acting on an arc is important when designing furnaces, controlling and automating their work. The effect of electromagnetic arc blowing has a negative effect on technical and economic indicators of the furnace, since the arc is removed from dimples in metal and slag. Radiation of the arc on walls and arch increases. And the effective power absorbed by the metal decreases. For this and a number of other tasks, it is necessary to know the dynamic behavior of the arc, which is largely determined by the instantaneous values and directions of the individual forces and the resultant force. The paper discusses the behavior of an electromagnetic force acting on an arc column from currents flowing through a liquid metal and currents flowing through other parallel arcs and graphitized electrodes in a three-phase AC arc furnace. It was assumed that the arcs burn perpendicular to the surface of the metal bath (their axes coincide with the axes of the electrodes) and effective value of the linear currents in different phases is the same. A mathematical model is proposed for calculating the instantaneous values and directions of the main electromagnetic forces acting on arcs in a three-phase arc furnace, allowing to reveal the nature of arcs dynamic behavior. A computer program has been created that makes it possible to visualize the behavior of a hodograph of forces acting on an arc. Hodographs of forces acting on the arc from the currents flowing through the melt are shown; they are ellipses lying in a horizontal plane. The resulting force deflecting an arc is also an even harmonic function with a frequency twice as high as the industrial frequency of the current. Its hodograph is an ellipse lying in a horizontal plane, the big semi-axis of which makes an angle of 20 – 80° with a line connecting the center of decay of the electrodes and the electrode axis.

The authors have carried out the investigations of fluxing agent containing silicomanganese slag with a flux additive based on gas treatment dust of aluminum production. Influence of carbon-fluorine-containing additive introduction on total oxygen and hydrogen content in weld metal has been studied, as well as its influence on impact strength at positive and negative temperatures. For fluxing agent manufacture, silicomanganese slag was used as a base, and aluminum production electrostatic precipitators dust was used as additive. Silicomanganese slag is produced by the West Siberian Electrometallurgical Plant; dust is from aluminum production electrostatic precipitators (carbonfluorine- containing adding) of RUSAL Co. Samples were welded on ASAW-1250 welding tractor. Chemical composition of studied welded samples was investigated according to GOST 10543 – 98 by atomic emission method on DFS-71 spectrometer and by X-ray fluorescence method on XRF-1800 spectrometer. Fractional gas analysis was performed using LECO TS-600 analyzer. Welded samples were tested for impact strength at positive and negative temperatures using impact pendulum-type testing machine according to GOST 9454 – 78. When using a carbon-fluorine-containing flux additive in welding flux based on silicomanganese slag, amount of oxygen and hydrogen in weld metal decreases, while impact strength increases at positive and negative temperatures. Dependences of the amount of oxygen and hydrogen in weld metal and impact strength on the amount of introduced carbonfluorine- containing flux additive were constructed.

The article presents original experimental data on surface tension of the melts Fe100 – x Mnx (x = 4 ... 13 wt. %). Surface tension and density of the melt was measured by the method of sessile drop at heating from the liquidus temperature up to 1780 °C and subsequent cooling of the sample in the atmosphere of high-purity helium. Temperature and concentration dependences of surface tension and density of Fe – Mn melts was constructed. Manganese is a surface-active substance in iron melt. The value of surface tension coefficient of Fe – Mn melts decreases while Mn content increases. Experimental data on the surface tension of Fe – Mn melts is consistent with the theoretical dependences (Pavlova-Popiel equation and the Shishkovsky equation). During the study of microheterogeneity of Fe – Mn melts, correlation between the values of kinematic viscosity, surface tension and density was determined. Dependence of the fluidity of Fe – Mn melts on their density in the cooling mode has a linear character which indicates the implementation of the Bachinsky law. Discrepancy of values of the ratio of melt viscosity to the surface tension coefficient was obtained from experimental data and was calculated by the empirical formula. According to the experimental data on viscosity and surface tension of Fe – Mn melts, the authors have evaluated the entropy change in volume of the melt and change of surface entropy of the melt, respectively. Surface entropy of the melt and entropy in the melt volume decreases in absolute value with increase of Mn content in it. According to the results of the work, it was concluded that there is no destruction of the microheterogeneous structure of Fe100 – x Mnx melts (x = 4 ... 13 wt. %) when heated up to 1780 °С.

1.7 %) contents on phase transformations, structure formation processes and mechanical properties of Fe – 25Mn – 5Ni – Al – C steels was studied theoretically and experimentally. The authors have estimated intervals of optimal crystallization regimes and subsequent deformation-thermal effects for obtaining austenitic steels with high specific strength. Measurements of hardness on the section of samples and mechanical tests in a wide interval of temperatures of cold, warm and hot deformation were performed as well as the assessment of phase structure of steels (alloys) on the basis of Fe – 25Mn – 5Ni– – Al – C. In a cast state alloy with 5 % of Al was non-magnetic, i.e. it had austenitic structure; alloys with 10 – 15 % of Al were magnetic with two-phase structure (γ + α). Aluminum considerably increases deformation resistance. At the same time values σ1 and σmax grow, i.e. also deformation hardening grows and softening processes are slowed down. With growth of deformation rate, influence of Al becomes stronger. Austenitic high-manganese alloys with 5 % of Al both with low and with high content of carbon have rather high plasticity and durability, and differ in high stability of austenite. Alloying with nickel increases plasticity. Alloys with Al less than 10 % are rather plastic also in a cast state. High-manganese (from 25 % of Mn) alloys with Al content to 5 – 7 % can be considered as high-strength cold-resistant and heat-resistant with thermally and mechanically stable austenite up to carbon content ~1.5 %.

Numerical relation of cast iron chill characteristics (distance of chilled layer H and volume quota of ledeburite in it Qл ) with its carbon equivalent СE was investigared. This data helps to prognosticate with high probability the evolution of the surface chilled layer forming at the production of castings with different thickness from cast iron of various chemical compositions. The object of study is the unalloyed induction melted cast iron with eight variants of chemical composition with carbon equivalent from 3.30 up to 5.53 %. From these cast irons we made the step-by-step castings with steps sizes of 10×60 mm and thickness of 5, 10, 20 and 40 mm. The distance (depth) of chilled layer was measured at the fractures of the castings and gaged on thickness of full chill zone. Ledeburite volume quota was detected by metallographic method using “Nexsys-Image expert pro 3” computer program. According to experimental data, when the casting thickness is 5 and 10 mm the through (at all thickness) full chill is formed at carbon equivalent ≤ 4.08 % and ≤ 3.67 % consequently. At the castings with 20 and 40 mm thickness the zone of full chill is absent, and in this case the chilled layer depth increases with a decrease of carbon equivalent and decreases with an increase of casting’s thickness X. The dependence of H from СЕ have the exponential character and can be described by the equation H = A exp (–k СE ), where A and k are empirical coefficients. Ledeburite volume quota near the contact surface of casting with chiller is near 90 %, but with an increase in the distance from the surface it decreases with different intensity depending on changes of carbon equivalent and casting’s thickness. By mathematical processing of the experimental data received for the distance of 5 mm from the contact surface of the casting with chiller, we have detected that numerical re lation Qл in casting chilled layer with value of CE can be described by the exponential dependence

The authors have conducted a comparative analysis of diffusion layers of steels of various structural classes manufactured by complex technology including laser remelting of powder material and plasma nitriding. Parameters of diffusion layers of bainitic steel (Fe – 0.09 % C – 1 % Cr – 2 % Ni – 1 % Mo – 1 % Cu) and martensitic steel (Fe – 0.25 % C – 13 % Cr – 2 % Ni) manufactured by direct laser deposition (DLD) and austenitic steel (Fe – 0.03 % C – 17 % Cr – – 14 % Ni – 3 % Mo) manufactured by selective laser melting (SLM) were investigated. During plasma nitriding at 540 °C for 24 h of martensitic and austenitic steels, diffusion layer of 140 – 160 μm was formed, additionally maximum microhardness of surface layer was 800 HV0.1 and 1050 HV0.1 and it is almost constant on thickness of 100 μm. Diffusing layer of bainitic steel is 900 μm and its microhardness monotonously decreases from the surface. Reinforcing phases of nitrided layer were determined by X-ray analysis: γ′ (Fe4N) is fixed in the bainitic steel, γ′ and CrN are fixed in martensitic and austenitic steels. Moreover on the surface of austenitic steel solid nitrided layer is formed. The influence of heat treatment after laser remelting of powder material was also studied. It was determined, that despite decreasing of crystal structure defects after heat treatment, the thickness of nitrided layer changes slightly. Also the authors have investigated the influence of porosity of austenitic steel on the thickness of nitrided layer. It was shown, that porosity of 0.5 – 2.0 % doesn’t result in changing of diffusion layer’s thickness.

During the study of technological data of the process of liquid iron transportation, it was found that the number of locomotives and mixers depending on the duration of operations and especially on the inter-operational downtime does not always ensure normal rhythm of the main production. It leads to significant production losses, therefore, the work of the producing and transport complex is not effective enough. The authors have developed a simulation model of a logistics system for transporting liquid iron at a metallurgical plant. The study and construction of the model was performed using AnyLogic. Real data from production, namely the schedule of blast furnace smelting for a three-week period, was used as the initial data. To prove adequacy of the model, the results were compared with the actual tact of the mixers movement, as well as with the theoretical need of the converter shop. Values of the liquid iron weight delivered to the converter shop were obtained during the simulation and were related to the theoretical ones. Efficiency of the model is achieved by automatically collecting in real time of statistical values of the parameters of simulation objects. The system analyzes the collected data and makes decisions based on them for a short period of time (less than one second). In default operation mode of the simulation model, motion of the mixers is controlled automatically without participation of the dispatcher, which improves efficiency, as well as decision-making speed. Such model provides simulation of failures in operation of the converter shop. According to the simulation results, it can be concluded that the system delivers less liquid iron to a converter shop, but retains its rhythm. After resuming the operation of all converters, the tact of transportation reaches the required level.

The article notes the increasing role of ferroalloy sub-sector in the qualitative development of metallurgy. Progress predicts of modern metallurgy are difficult in the context of increasing risks of global economic development. The high volatility of domestic producers’ prices for the main ferroalloys also has a negative impact. It is necessary to develop methodological tools for forecasting changes in market prices for metallurgical products with a high degree of accuracy. One of the important areas of application in metallurgy forecasting tools is construction of a model for forecasting the cost of ferroalloy products. It is the main purpose of the study. On the example of constructing a forecast model for changing the price of ferrosilicon, relevance of the neural network approach to forecasting the cost of ferroalloy products was substantiated. As part of the tasks of industry development, the capabilities of neural networks have been poorly studied to date. Formal description of the time series forecasting model based on neural networks is given. When constructing neural networks, any time series problem is represented as a multidimensional regression problem. The main parameters of predictive networks training are highlighted. The average price of ferrosilicon on the Russian market and the prices in the Russian regions were used as input variables. The networks that meet the qualitative criteria of forecasting models were trained. Selection of the networks was carried out taking into account the results of graphical analysis and cross-checking. A neural network model was constructed to predict the change in ferrosilicon price in the short term with high accuracy. This model can be useful in strategic decisions justifying in the activities of industry research institutes and metallurgical enterprises.

The main component of natural gas is methane CH4 , that is, a component consisting of two active reducing agents for iron – carbon and hydrogen. Previously, computer simulations have found that the reduction of iron from magnetite with carbon begins at 680 °C, and its reduction with hydrogen – at 350 °C. In this paper it is shown that the beginning of the reduction of iron with methane should be expected at a temperature of 530 °C. However, this temperature for natural gas, obtained from gas condensate fields and containing up to 10 % of heavy hydrocarbons and impurities, increases to 550 °C. When using natural gas together with oxygen in the ratio CH4 : O2 = 2:1, temperature of the beginning of reduction also increases to 620 °C. In addition, a calculation formula was proposed for Fe – O – C – H system, which allows predicting the formation of a “pure” phase of iron at 1500 °C based on the chemical composition of the reducing gas mixture.