The effect of introduction of chromium with increased concentration as a reducing agent was studied at the manufacture of flux cored wire of the Fe – C – Si – Мn – Сr – Ni – Mo system. Metal welding deposition was carried out on the plates of St3 steel with the help of AN-26С flux with preliminary heating of the base metal to 250 – 300 °С. Flux cored wire of5 mmin diameter, made on a laboratory machine, was deposited on ASAW-1250 welding tractor in the following modes: current 420 –520 A, voltage 28 – 32 V, welding speed 7.2 – 9.0 m/h. After it the metal was cooled at room temperature. For manufacture of the samples, the corresponding powdery materials were used as fillers (charge): iron powder PZhV1 according to GOST (State Standards) 9849 – 86, FS 75 ferrosilicon powder according to GOST 1415 – 93, FKh900A high carbon ferrochrome powder according to GOST 4757 – 91, FMn 78(A) carbonaceous ferromanganese powder according to GOST 4755 – 91, PNK-1L5 nickel powder according to GOST 9722 – 97, FMo60 ferromolybdenum powder according to GOST 4759 – 91, FV50U 0.6 ferrovanadium powder according to GOST 27130 – 94, PC-1U cobalt powder according to GOST 9721 – 79 and tungsten powder PVN TU 48-19-72-92. It was determined that carbon, manganese, chromium, molybdenum, nickel and, to a small extent, vanadium, within the limits studied, simultaneously increase hardness of the deposited layer and decrease wear rate of the samples. It is shown that the low viscosity of the matrix does not allow tungsten carbides to be kept on the surface, as a result of which the wear is carried out not according to the uniform abrasion of the surface, but according to the scheme of spalling high-strength carbides particles from the matrix. As a result, new cracks are formed in the matrix, contributing to its additional wear. According to the results of the multifactor correlation analysis, dependences of hardness and wear resistance of the deposited layer on mass fraction of the elements included in the flux-cored wires of the Fe – C – Si – Мn – Сr – Ni – Mo system were determined. The obtained dependences can be used to predict hardness and wear resistance of the deposited layer with a change in the chemical composition of the weld metal.

High performance of rolling and tube rolling mills, good quality of finished metal products can be obtained by heating metal billets with minimal oxidation and decarburization in heating furnaces. Such conditions can be provided by annular furnaces, which are widely used in the rolling production of pipes, railway wheels and tires. High-quality heating allows us to obtain the structure of metal products with given thermal and working properties, as well as the plasticity necessary for subsequent mechanical processing. In this paper, we consider thermal engineering features of the operation of an annular furnace for heating billets before rolling at “Chelyabinsk Tube Rolling Plant” PJSC (ChTPZ). The problems arising during the operation of thermal unit were analyzed: high specific fuel consumption for billets heating; high temperatures of walls external surfaces and roof external surfaces; low heating rate of the billet; large amount of air leaks into the furnace working space. Also design of gas-burning devices does not provide the possibility of regulating gas supply in a large range of loads, up to a periodic complete shutdown. And thermal energy of waste gases is practically not used. Metal heating has been analyzed and annular furnace heat balance has been compiled. Analysis of the results of computational studies has revealed factors that reduce energy efficiency of the existing furnace design. The measures were proposed for its modernization in order to reduce fuel consumption and to increase productivity (use of fibrous refractory materials, regenerative burners, non-water-cooled partitions, etc.). To assess impact of the proposed measures, the furnace heat balance after its systems reconstruction and assembly has been compiled, the main indicators of the furnace heat operation have been determined. When implementing proposed measures, significant economic effect is expected, including improvement in quality of metal heating while reducing fuel consumption and increasing productivity of the unit. In particular, after furnace reconstruction it is expected to increase the total (by 18.1 %) and heat (by 31.0 %) efficiency of the furnace, and to decrease (to48.3 kgconditional fuel/ton) specific fuel consumption. 

Using the example of hardened carbon steels (steel 45, U8), the effect of combination of various surface hardening technologies is considered (using electromechanical processing, surface plastic deformation, non-abrasive ultrasonic finishing and their combination) on changes in structural state and surface microhardness, cyclic durability of hardened specimens and fatigue failure mechanisms. The studies were carried out by the methods of optical and scanning electron microscopy and by microhardness and fatigue tests. It is shown that for the investigated steels in quenched state, a high-speed pulsed thermo-deformation effect during electromechanical processing is accompanied by an increase in the surface microhardness (by more than 50 %) and decrease in the fatigue limit (by 20 – 30 %). Such a change in properties is associated with formation in the surface layer of substantially non-equilibrium, inhomogeneous in chemical composition, ultradispersed phases with increased hardness. At the same time, in the near-surface metal volumes tempering processes of the hardened structure proceed with the formation of softening zones and tensile residual stresses, accompanied by a decrease in the microhardness in these zones and the fatigue limit of the specimens. Such effects reduce some of the materials performance characteristics during surface hardening. The ways to improve the properties of such products due to additional technological operations require further studies. Combined surface hardening (based on electromechanical processing, surface plastic deformation and non-abrasive ultrasonic finishing) of carbon steels allows, due to variations in the intensity of temperature and deformation effects, to purposefully change the structural-phase composition and stress-strain state of the surface and near-surface metal layers. As a result, it becomes possible to form a balanced complex of strength and fatigue characteristics of the samples, depending on the preliminary heat treatment of steel. The operations of surface plastic deformation and non-abrasive ultrasonic finishing after electromechanical hardening, due to intensive plastic deformation provide smoothing of the surface and healing of near-surface defects and allow correction of stress-strain state of the processed metal. It provides an increase in microhardness in the tempering zone by 20 – 25 % and the fatigue limit of the samples by 25 – 30 %. 

Boriding is a common method of thermo-chemical treatment of steel products. It increases their hardness and wear resistance, but also increases the surface fragility, has a long duration and high labor intensity. The combined coating with boron and vanadium is used to improve the properties, and it is possible to apply microarc surface alloying to reduce the duration of the diffusion saturation process. This makes it possible to intensify the diffusion of alloying elements by forming a gas discharge zone at the surface of the steel product. The aim of this work was to study the structure, phase composition, mechanical properties and wear resistance of steel after boriding and vanadation. During the experiments, a lubricant containing boron carbide powders B4C and ferrovanadium FeV80 were used, which was applied to the surface of the steel sample. During boriding and vanadation of steel a surface layer with a thickness of 150 – 190 μm is formed. It has a base with microhardness of 7.8 – 8.3 GPa and light grey granular inclusions and eutectic areas with microhardness of 13.5 – 14.0 GPa. Further there is a carbonized layer of eutectoid concentration, passing into the original ferrite-perlite structure. The content of alloying elements in the characteristic points of the surface layer was determined, which confirmed the increased content of carbon, vanadium and boron in the base layer, areas of eutectic and carbide phase. X-ray phase analysis revealed the presence of iron borides FeB and Fe2B, vanadium borides VB2 and V2B3 and vanadium carbide VC0.88 in the surface layer. Mechanical properties of coatings were studied by microindentation of its cross-section with registration and analysis of deformation diagram under loading and subsequent unloading of the indenter. Hardness at indentation in the base layer increased to 7.95 GPa, in dispersed inclusions – to 13.90 GPa. The modulus of elasticity for indentation in the base and inclusions is 238 MPa and 340 MPa, respectively. Creep and proportion of the plastic component in microindentation is naturally reduced with increase in hardness. Fine inclusions of iron borides, vanadium borides and carbides significantly increase the steel wear resistance. It has increased in 4 times during friction against the fixed abrasive particles in comparison with the initial state.

On the basis of conducted experimental studies, regularities of the influence of temperature-speed rolling conditions on the plasticity and deformation resistance in the zones of continuously cast billets of alloy rail steels of E76KhF, E76KhSF grades are determined and scientifically substantiated. The results indicate the complex nature of dependence of rail steel E76KhF plasticity on deformation temperature. In particular, for near-surface layers of continuously cast billets, a noticeable decrease in plasticity in the temperature range of 1025 – 1075 °Cwas recorded, which is absent for the layers located in central zone of that billets. Generalization of the results of plasticity studies of various layers of continuously cast rail E76KhF steel billets has shown that absolute values of the plasticity criterion are significantly reduced with the distance from the surface to the central zone. This fact can be explained by a coarse-grained structure and increased concentration of non-metallic inclusions in the central zone of continuously cast billets relative to their surface layers; it was confirmed by the results of metallographic studies. In particular, it was found that the average grains diameter in the surface layer of deformed continuously cast billets is in 1.3 – 2.1 times less compared to the central zone. There was confirmed the presence of significant concentrations of non-deformable inclusions of the silicate type (Al₂O₃· SiO₂ ; FeO·SiO₂ ; MnO·SiO₂ ), which have most negative influence on steel plasticity while in the surface area such inclusions are absent. On the basis of conducted researches it was established that with increase in deformation temperature of rail steel E76KhSF there is a decrease in resistance to plastic deformation according to the exponential law. In this case, absolute values of the steel deformation resistance are reduced with the distance from the surface to the central zone of continuously cast billets, which is associated with the above illustrated increase in grain size and localization of non-metallic inclusions. The revealed tendency to reduce the deformation resistance from the surface layers to the center of continuously cast billets is maintained regardless to deformation rate, while the absolute values of the deformation resistance increase significantly with the growth of deformation rate from 1 to 10 s^–1. Mathematical processing of the obtained experimental data allowed to obtain regression equations that help to predict plastic and deformation properties of alloyed rail steels of E76KhF and E76KhSF grades with a sufficient degree of reliability under the specified rolling conditions and are complex theoretical basis for the development and improvement of new heating modes of billets for rolling and rail rolling schemes. Adequacy of the obtained experimental dependences is confirmed by results of pilot industrial testing of the new mode of railway rails production on the universal rail mill of “EVRAZ ZSMK”.

The urgent task is the development of reliable and durable composite materials, manufactured from various components in terms of properties. Multilayered steel is among these materials. The alternation of a large number of heterogeneous layers makes it possible to obtain a complex of properties unattainable for homogeneous steel. To create a series of composite materials for the production of cutting tools based on instrumental powder steels (in particular, Uddeholm Elmax steel), the use of diffusion welding is possible. Study of the effect of heat treatment modes on the structure and performance properties of a multilayer composition based on Uddeholm Elmax and low-carbon stainless AISI420MoV steel has become the goal of this paper. The structures of initial steels and composite material after annealing, and then after quenching and tempering were studied. Metallographic examination of the samples was carried out with the help of “Thixomet” image analyzer. The structure of all samples was considered in the longitudinal section. A general view of the samples surface was investigated for the presence of any defects and nonmetallic inclusions. For this, panoramic images of the samples were considered. Carbide particle size measurements were also performed and the layers width in the multilayer composition was measured. It is shown that the material studied has a pronounced layered structure with a sharp transition from one layer to the next one. Technology used in the production of the composite material ensures that there is no transition zone between the layers. Also, there were no typical defects of diffusion welding – bundles, pores, oxide inclusions. It was established that during thermal processing the size of carbides inclusions in the structure of the composite material decreases, and their number increases. The layers formed by Uddeholm Elmax and AISI420MoV are distinguished by the number of such inclusions. The structural transformations occurring during thermal processing lead to an increase in the surface hardness (according to Rockwell) of the material under investigation. A study was also made of the corrosion resistance and microhardness of the composite material. The results of the work made it possible to recommend a heat treatment regime for the composition studied. 

The article considers results of the evaluation of rational frequency effecting the sample when implementing the method of determining the fatigue characteristics of materials based on synergistically organized emission of stress waves. The essence of this process lies in the fact that a flow of the emission signal is formed with a small-scale loading of the tested sample at each step of loading. At the same time, another series of dislocations is being generated, capable of reaching the crystal surface at the next moment of loading and emitting a stress wave. The magnitude of this signal characterizes the processes occurring in the material at a particular load, and allows the power parameters corresponding to such value as endurance limit to be recorded. The purpose of this work is to determine the frequency of small-scale loading, providing the maximum wave signal when implementing the method for determining the fatigue characteristics of materials based on synergistically organized emission of stress waves. The analysis of the movement of material elements was made. Based on previously published materials on the use of synergistically organized acoustic emission, the process of behavior of the metal structural components was analyzed; the process of the behavior of its grain under the influence of dislocation movements is identified and described. The strength of each such impact was represented by the delta function. The behavior of metal grains was described by the second order differential equation. The probability of a grain moving from impulse action from the side of lying crystals and from its own impulses is described by the density of movement probability of this grain. Considering jointly the dynamic and probabilistic description of the grain behavior, the Kolmogorov – Focker – Planck equation was obtained. Due to the fact that in the present work, the oscillatory nature of the metal grain movement was of interest, the above-mentioned equation was transformed into a wave-mechanical function of the process of grain behavior. The solution of wave-mechanical function is wave equation. As a result of consideration of the wave equation, natural frequency of material grain oscillations was revealed. This frequency falls in the range of frequencies that can be reproduced under stepwise loading of the test sample. This makes it possible to realize a resonance effect as applied to behavior of the metal crystal structure. Thus, frequency at which fluctuations in the material structure at the grain level will resonate with an external effect on the sample is determined. Resonant interaction of the material structure and external incremental loading of the sample will ensure a more powerful value of the emission signal at the same value of the steps under small-scale loading.

Nickel-cobalt alloys are widely used in modern technology. Manganese is one of the alloying components in these alloys. Oxygen is a harmful impurity in Ni – Co alloys; it presents in the metal in dissolved form or in the form of oxide nonmetallic inclusions. The presence of oxygen in these alloys degrades their service properties. The study of oxygen solution thermodynamics in manganese-containing Ni – Co melts is of considerable interest for the practice of such alloys production. Thermodynamic analysis of oxygen solutions in manganese-containing Ni – Co melts has been carried out. The equilibrium constant of interaction of manganese and oxygen dissolved in the nickel-cobalt melts, the activity coefficients at infinite dilution, and the interaction parameters characterizing these solutions were determined for melts of different composition. In the interaction of manganese with oxygen in Ni – Co melts, the oxide phase, in addition to MnO, contains NiO and CoO. The values of the mole fractions of MnO, NiO and CoO in the oxide phase were calculated at 1873 K for different manganese concentrations in Ni – Co melts. In the case of nickel melt, even when manganese content is higher than 0.1 %, the mole fraction of manganese oxide is close to unity. As the cobalt content in the melt increases, the mole fraction of manganese oxide in the oxide phase decreases. In the case of pure cobalt, it is close to unity with manganese contents above 0.7 %. The dependences of the oxygen solubility on contents of cobalt and manganese in the studied melts were calculated. In nickel-cobalt melts, manganese is characterized by a high affinity for oxygen. The deoxidizing ability of manganese decreases with increasing cobalt content in the melt. In pure cobalt it is significantly lower than in pure nickel. The oxygen solubility curves in manganese-containing Ni – Co melts pass through a minimum, the position of which shifts to the higher manganese content with an increase in cobalt content in the melt. 

The article considers the tasks of system analysis and development of models required for the synthesis of a situational (multivariate) procedure for estimating the standard duration of manufacturing a batch of products within a multi-structural steel wire complex (object of study), including independently functioning units with continuous, semi-continuous and discrete technological processes (etching, drawing, annealing, copper plating), which are connected by a single material flow. The complex is distinguished by: a variety of technological routes, allowing to produce a wide range of products (steel wire), corresponding to different standards, steel grades, diameters, shapes and masses of finished products; multivariate specialization of drawing mills; flexible connections between departments; parallel, sequential and combined work of the main and auxiliary equipment; equipment by specialized vehicles (cranes, conveyors, transfer carts, electric vehicles). During the system analysis of the research object, the following issues were resolved: a number of technological routes in the branches of complex were identified and described, their characteristics were evaluated. Graphic models of production processes have been developed, displaying sequence and parallelism of operations, their decomposition into elements and microelements for each compartment. The determining factors were identified characterizing the organization of production processes for all departments. Regulatory models have been developed for the duration of operations based on the integration of various research methods. The solution of the above task is based on the clock approach and includes: building a factor model of the piece situational tact of the s-type drawing mill, “pickling bath-tap” subsystem, heat treatment furnace, and the copper plating line. Additionally, the concept of piece equivalent operation of equipment was introduced to bring to a comparable form with the strokes of coarse-drawing mills. To ensure the coordinated work of the coarse drawing department with other departments, an appropriate amount of pickling, thermal, fine drawing equipment and copper plating has been determined. Models of interconnected part-time steps of the work of previous and subsequent branches (in relation to the rough drawing department) are formed. The degree of work coordination was determined on the basis of comparison of the part-time work cycles of equipment and vehicles at the entrance and exit of each section. To do this, regulatory models of vehicle operation were pre-built. The results of the performed work allow us to proceed to the presentation of the algorithm itself for estimating production duration of batches of steel wire, which will be presented in the second message. 

Currently, the processing technologies of oxidized nickel ores are characterized by multistage and the use of expensive raw materials, which significantly affects the cost of the final product. The experience of Russian manufacturers, such as “Yuzhuralnickel” and PJSC “Ufaleynickel”, has confirmed that the current technology does not allow to achieve economic efficiency under the circumstances. Basis of the technology of these enterprises was mine matte smelting at shaft furnace. Due to the high coke consumption (20 – 30 tons per 1 ton of Nickel), the cost of nickel produced in this case was so high that it made the technology economically inefficient in today’s market conditions. Nowadays, on the international market of ferronickel there is a downward trend in the share of high-grade nickel in nickel alloys consumption due to the increase in production of crude ferronickel and metallized forms with reduced nickel content. The solution of the problem can be the development of a new, more energy-efficient technology for oxidized nickel ores processing. The chair “Energy-Efficient and Resource-Saving Industrial Technologies” of NUST “MISIS” has developed an innovative technology of processing of complex ores and industrial waste in the furnace of bubbling type PM6 (Process MISIS–6). The paper presents a brief description of the technology and the experiments results of two-stage technology for the production of commercial ferronickel from oxidized nickel ores of theSouthern Urals.