The article presents conclusions of the commission, headed by D.I. Mendeleev, directed at the end of the 19th century to the Urals, to find out the reasons for the lag of Ural metallurgical industry from the growth of this industry in Southern Russia. The commission examined the iron ore base of the Urals, its timber reserves and the ways of its delivery to the plants, and established the type of plant owners. Important conclusions were made about the further development of industry.

In connection with the development of copper and molybdenum production in Armenia, it becomes necessary to develop a technology for processing the slags of the functioning metallurgical plants to extract valuable metals from these slags. It concerns the copper slags of Alaverdi Copper-Smelting Plant with a content of FeO ~50  % and the molybdenum slags of Yerevan “Pure Iron” Plant with a content of SiO2 ~80  %. These slags are obtained at high temperatures (with FeO·SiO2 , CaO·SiO2 , Fe3 O4 ) and, therefore, they are less active to be used later. Meanwhile, the mentioned slags are rich in iron and silicon oxides and can serve as a cheap raw material for producing iron silicides. The iron silicides can be used in micro- and nanoelectronics, as well as in metallurgy as an alloying additive in the production of steels of special physical and chemical properties. The production of such valuable silicides from an inexpensive raw material is important for Republic of Armenia and is of not only economic, but also ecological significance. To obtain iron silicides, a method of combined aluminothermal reduction of primarily mechanoactivated copper and molybdenum slags is proposed. The preliminary mechanoactivation allows to purposefully affect the structure of the reaction mixture and parameters of the self-propagating high-temperature synthesis (SHS), thus ensuring the possibility of regulating the structure and phase composition of the synthesized silicides. This work considers issues on the impact of transformation and phase formation on the morphology of slags of copper and molybdenum production in the functioning Armenian metallurgical plants at mechanochemical activation by the method of fine grinding in a vibromill. It is shown that at fine grinding (up to 10  mcm), the slags, containing small-reactivity complex compounds of iron and silicon (fayalite, magnetite, quarzite) undergo profound chemical changes, transforming into amorphous oxides. The obtained activated oxides can serve as a raw material for producing iron- and silicon-containing alloys – iron silicides.

Based on the system approach and on the experience accumulated at theoretical data, design and industrial development of bar rolling, the Chair “Metal Forming” of Ural Federal University develops the universal “Concept of optimum calibration”. The general ideology of roll pass design optimization is stated in article “The concept of optimal bar roll pass design. Report 1. Basic statements”. In the article “The concept of optimal bar roll pass design. Report 2. Calibers space” the structure, appointment and maintenance of the information block reflecting so-called “calibers space” are considered. According to the general concept of optimization, the following task that needs to be solved is the problem of creation of information block so-called “space of schemes of roll pass design” which will be used further as the first space of optimization. The concept “space of schemes of roll pass design of a bar-rolling mill” is considered as the space containing all possible virtual schemes of rolling of a concrete profile on the concrete rolling mill. For formation of the space of schemes of rail calibrations it is necessary to generate separate virtual schemes and to consistently fill this space with them. Thus, the space of calibrations schemes is formed of separate unique calibrations schemes. For formation of this space from separate calibers, it is offered to use the specialized algorithms which are “generators of schemes of roll pass design”. As an example, the structure of the generator prepared for creation of such space for rolling of railway rails is considered. It is revealed that all known rail calibrations can be presented in the form of essentially the same block structure which is used as the central element of the schemes generator of rail calibrations. Usage of described and similar generators in relation to rolling process of a concrete profile on the concrete rolling mill allows obtaining spaces of acceptable schemes of calibrations. Such spaces are necessary for the subsequent optimizing procedures for search of the best calibration scheme from all possible calibrations. The considered approach for creation of calibrations schemes space can be used during creation of computer-aided engineering systems and optimization of calibrations of rolling rolls.

The article gives an overview of well-known hypotheses and theories on ultimate state of metals. Processes in metals when stress is applied are described. Multifunctional equation for ultimate strain dependence from density (opening) is offered with all the factors of metal’s ultimate state before fracture. Phases of the fracture of deformed polycrystal structure are specified. An equation is presented that relates the ultimate deformation of a metal to fracture with all the characteristics that determine the limiting state of the metal. Two- or three- compound energy failure criteria equations used for quality estimation of metal structure and performance when main pipeline operating are given for such criteria as energy capacity, crack initiation, crack proliferation, fragility and scale. The fracture criteria calculation for Kh70 steel samples of pipes after operation for 5, 20 and 24  years was made as an example. The comparative analysis of complex fracture criteria values for Kh70 steel pipelines of different lifespans has been carried out. After 5, 20 and 24 years of usage mechanical characteristics of steel Kh70 of main pipelines haven’t changed dramatically, and fracture criteria are inclined to decrease from 21 to 48.5  %, crack proliferation and fragility criteria are the most changeable. At mesolevel the nature of crack initiation is the same for all classes of steel. Under the influence of operating loads, energy intensity, i.e. the ability of metal to withstand any loads with increasing service life is significantly reduced, which is confirmed by the change in the fracture criteria considered in the article. It is shown that the fracture criteria can be used to predict the performance of pipeline steels after a long period of operation.

As a result of a survey of gas exhaust systems of low-tonnage electric arc furnaces (from 3 to 10 tons) operated in the foundries of machine-building enterprises, the bottlenecks were identified, due to which a large amount of gas-dust emissions gets into the production rooms and pollutes the air in the working areas. First of all, it occurs due to the design schemes imperfection of the evacuation systems of gas and dust ejected from the furnace cavity through the outlet channel, the working window, gaps between its body and the roof, between edges of the holes in its upper part and the electrodes lowered through them. In particular, joint units of the rotary collection hoods with the gas exhaust pipelines in these systems do not provide proper sealing of movable joints. In this regard, the authors have proposed an improved design of rotation mechanism of the furnace collection hood, which involves the use of two sand gates. These gates eliminate the possibility of harmful emissions release between movably connected elements of the system into the environment. To begin designing of the industrial sample of a modernized mechanism, a method for calculating the energy-power parameters of its drive has been developed. A preliminary validation of the correctness of the taken technical decisions and of the obtained calculating dependencies was performed on the operating model of the investigated system manufactured on a 1:10 scale relative to the industrial sample. For the model research an instrumentation complex that included strain gauge transducer, AC amplifier, analogto-digital converter and computer was used. During this research the load acting on the model drive of the collection hood rotation mechanism when it was transferred from the working position to the parking one and back was fixed. At the same time, the load was measured for two cases: in the absence and in the presence of sand in the gates which ensure sealing of the movably joint elements of the investigated mechanical system. It was established that the portion of resistance forces arising in two sand gates during relative rotation of the moving element is 20  –  26  % of total load on the mechanism drive depending on angular velocity of the cantilever with collection hood. Similarly, this indicator calculated from obtained theoretical dependences was in the range of 17  –  23  % for the rotation mechanisms of collection hood of arc furnaces with a tonnage of 3 to 10  tons. Video filming of the smoke movement patterns, which flows from the furnace model through the existing gaps between its body and roof during the steelmaking process imitating, confirmed the reliability of the sand gates that provide complete sealing at the joint units of the moving parts of the collection hood rotation mechanism. Practical use of the proposed technical solution allows increasing of efficiency of evacuation of the harmful gas and dust emissions from the working zone of smelting furnaces used in the foundry.

The paper presents results of the investigation of phasestructural transformations and volumetric changes that occur during heating in high-silicon spring steel 60Si2CrV subjected to Q&P(quenching and partition) treatment. Chemical composition of the steel was: 0.53  %  C; 1.46  %  Si; 0.44  %  Mn; 0.95 % Cr; 0.10 % V; 0.016 % S; 0.013  %  P. Steel samples were subjected to Q-n-P treatment as follows: a) austenitization at 880  °C; b) quenching with the cooling stop at 120, 160, 200 and 240  °C; c) subsequent holding at 220, 250 and 300  °С with duration from 10 to 3600  s; d) final cooling in water. The volumetric changes during heating were studied using an optical differential dilatometer at a heating rate of 1  K/s. As a reference, a sample of the same steel stabilized by high tempering was used. The amount of retained austenite was determined by X-ray diffraction using a diffractometer DRON-3 with Fe-radiation. It is found that on the heating curves of Q&P samples, the sections corresponding to different transformations during tempering are clearly identified. On dilatograms of the Q&P samples, dilatometric effect corresponding to the second transformation during tempering (270  –  430  °C) was found to be increased dramatically, indicating an increase in retained austenite amount compared to the quenched state as a result of Q&P treatment (as confirmed by Xray study). At the same time, value of the effect corresponding to the third transformation during tempering was found to be decreased. To obtain the maximum amount of retained austenite in 60Si2CrV steel, the partitioning temperature should be of 260  –  300  °С, while the quenching completion temperature should be of 160  –  240  °С. The amount of retained austenite rises substantially as the quenching temperature increases. Duration of the partitioning stage should be selected taking into account the extreme character of austenite dependence on the partitioning time. As a result of the work, an effective applicability of the dilatometric method for analyzing the steel structural state and choosing the optimal mode of Q&P treatment was demonstrated.

Corrosion and cavitation resistance in seawater of high-strength economically alloyed nitrogen chromium–nickel–manganese steels Cr19Mn10Ni6Mo2N and Cr19Mn10Ni6Mo2Cu2N is experimentally studied compared to chromium-nickel steels Cr18Ni9 and Cr18Ni9N. Tests for resistance to pitting corrosion were carried out according to the chemical method in the test solution 100 g/l FeCl3 ·6H2 O. Resistance to general corrosion was assessed by tests in synthetic seawater (3  %  NaCl). Test for cavitation resistance in seawater was performed using a research stand of high-intensity cavitation effects with the use of ultrasonic devices UIP 1000  hd Hielscher Ultrasonic in 3  %  NaCl solution in water at a frequency of 20 kHz, a power of 1000  W and amplitude of 25 microns for 8  –  36  hours. The extent of damage and change in the surface microhardness, change in the phase composition and mass of the samples were assessed after cavitation. It is shown that steels Cr19Mn10Ni6Mo2N and Cr19Mn10Ni6Mo2Cu2N are more susceptible to pitting in seawater and in solution of ferric chloride, and have the general corrosion rate lower than that of chromium-nickel steels type Cr18Ni9. It is shown that ultrasonic cavitation can not only lead to surface damage due to erosion, enhance local corrosion, but also to changes in their physico-mechanical properties by strain hardening and phase transformations. Steels Cr19Mn10Ni6Mo2N and Cr19Mn10Ni6Mo2Cu2N with thermally and mechanically stable austenite are more resistant to ultrasonic cavitation in the seawater in comparison with chromium-nickel steels, especially those with less strength and less resistant steel Cr18Ni9. So subjected to cavitation in the seawater for 36 hours, samples of chromium-nickel steels Cr18Ni9 and Cr18Ni9N had a significant change in their condition: significant damage (etching) and surface hardening, and there was formation of a small amount of martensite in steel Cr18Ni9. Samples of steels Cr19Mn10Ni6Mo2N and Cr19Mn10Ni6Mo2Cu2N had only minor changes in surface conditions and hardening of the surface layers.

The article presents investigation results of the effect of inhomogeneity of boundary conditions on the intensity of metal cooling in the process of continuous casting of cylindrical billets from corrosionresistant steels. It is assumed that the boundary conditions are nonuniform along the billet perimeter. In the longitudinal direction, the cooling intensity is assumed to be constant within the cooled sector of the billet. During the research it was believed that there are flows of thermal energy between the cooling sectors. A comparative analysis of temperature gradients and resulting thermal stresses in the solidified billet at different cooling intensities realized in the secondary cooling zone was carried out The values of thermal stresses are compared with the maximum permissible for each grade of steel in order to find those cooling conditions in which the thermal stresses do not exceed the permissible values. Based on the results obtained, conclusions are drawn about the effect of cooling intensity on the occurrence of external and internal defects in the resulting cylindrical continuous cast billets. The authors have also made the conclusions about the effect of inhomogeneity of the boundary conditions on the formation of temperature fields in a solidified cylindrical continuously cast billet. The results of the conducted studies are presented in a graphic form and their detailed analysis is carried out. To calculate the temperature fields in the solidifying billet, a specially developed mathematical model was used, based on the equation of nonstationary heat conductivity. For the calculation of thermal stresses, known mathematical formulas have been used that allow calculating the values of thermal stresses arising between cooling zones in the solidifying billet during the continuous casting of steel. The obtained data are of high practical importance, since they can be used to develop rational cooling regimes, in which excess permissible thermal stresses will not be observed. This, as a consequence, will reduce the number of internal and external defects arising in the solidifying continuously cast billet.

Traditional methods of heat treatment are energy-intensive and time-consuming, so the task of increasing their efficiency is very relevant. The process of repeated high-speed heating with short-term aging in the temperature range of polymorphic pre-transformation and transformation from the viewpoint of evolution of structure, properties and character of the fracture of quenched high-carbon steels was investigated. In particular, it was found that high-speed heating (600  –  700  °C/s) and short-term holding (0.5  sec) followed by cooling in salted water (6  °C) leads to the formation of a structure not differing from the structure of low-drawn (200  °C, 2  hours) martensite of traditionally hardened steel with 4 times increase in elongation and 2  times contraction while maintaining strength during the tensile test. Short-term aging of 8  –  15  –  25  seconds with repeated quenching of high-carbon steels from 820  °С in cold salted water (6  °С) leads to formation of the structure of ultra-fine-lamellar, submicroplast, globular perlite. There is a three-dimensional nanostructuring of steel that differs from traditional hardening with high temperature tempering by the structure and properties: magnitude of the applied stresses, both at deformation stages and at fracture (increase in σ by 55  %, in σ0.2 – by 17  %, in ψ  –  8  times, in αn  –  by 80  %). Increase in short-time holding up to 40  –  50  sec, with repeated quenching from 820  °C leads, in contrast to the traditional one, to formation of the structure of ultra-small-malt martensite and to appearance in fracture on the slip planes of the patching structure, resembling a honeycomb in shape. After the low temperature tempering during the tensile test, all stages of deformation are presented. In fracture the crushing of pit structure and the absence of brittle tunnel pits are observed, plasticity is improved (δ  ~  1.5  times, ψ  –  3  times) at strength preservation.

The paper presents the results of investigation of phase-structural transformations and volumetric changes that occur during heating in high-silicon spring steel 60Si2CrV subjected to Q-n-P treatment. The chemical composition of steel was of 0.53 % C; 1.46 % Si; 0.44 % Mn; 0.95 % Cr; 0.10 % V; 0.016 % S; 0.013 % P. Steel samples were subjected to Q-n-P treatment as follows: a) austenitization at 880 °C, b) quenching with the cooling stop at 120, 160, 200 and 240 °C, c) subsequent holding  at 220, 250 and 300 ^оС with duration from 10 to 3600 s, d) final cooling in water. The volumetric changes during heating were studied using an optical differential dilatometer at a heating rate of 1 K/s. As a reference, a sample of the same steel stabilized by high tempering was used. The amount of retained austenite was determined by X-ray diffraction using a diffractometer DRON-3 with Fe radiation. It is found that on the heating curves of Q-n-P samples, the sections corresponding to different transformations during tempering are clearly identified. On the dilatograms of the Q-n-P samples, the dilatometric effect corresponding to the second transformation during tempering (270-430 °C) was found to be increased dramatically, indicating an increase in retained austenite amount compared to the quenched state as a result of Q-n-P treatment (as confirmed by X-ray study). At the same time, the value of the effect corresponding to the third transformation during tempering was found to be decreased. To obtain the maximum amount of retained austenite in 60С2ХФА steel, the partitioning temperature should be of 260-300 ^оС, while the quenching completion temperature should be of 160-240 ^оС. The amount of retained austenite rises substantially as the quenching temperature increases. The duration of the partitioning stage should be selected taking into account the extreme character of the austenite dependence on the partitioning time. As a result of the work, an effective applicability of the dilatometric method for analyzing the steel structural state and choosing the optimal mode of Q-n-P treatment was demonstrated.

The article is devoted to the development of a method for modeling the heating of oxidized metal billets, in which the dimensions and thickness of the scale layer vary with time. The approach used in this development facilitates the appliance of modern software packages for the analysis of objects with varying geometry; and due to this the complexity of developing mathematical models of several metallurgical processes can be dramatically reduced. To simulate the process of metal oxidation, the method of equivalent thermal conductivity was used. The experimental verification of the method is performed and the possibility of its use for improving the methods of controlling the processes of industrial heating is shown. This method was worked out during experiments on the furnace №3 with walking beam of the mill 150 at Nizhne-Serginsk Hardware and Metallurgical Plant. Calculations were made to determine the thickness of the scale layer, which varies with time; the corresponding dependencies were constructed. The problem was solved by ANSYS Multiphysics software package as a problem of non-stationary heat conduction with boundary conditions of the first kind. During modeling, a finite-element grid was constructed, sufficiently detailed to obtain reliable results and, at the same time, allowing to solve the problem on low-power computers. In the course of solution, a number of simplifications were applied, in particular, simplification of the computational algorithm, in which the thickness of the scale layer is uniquely determined by surface temperature of the billet. Temperature distribution along the billet’s thickness was determined. Graphs and isotherms were constructed to compare values of the temperatures in metal and in scale layer. Also, a comparison of the temperature differences in the scale layer determined by the calculation method was made for the furnace and experimental conditions. In this study, the problem is considered as nonstationary, with varying boundaries. The research object is preparation of the metal (real solid) with scale layer, increasing with time. When solving a problem, this real solid was replaced by a conditional one with constant averaged dimensions. According to the equality of thermophysical processes, properties of the conditional solid were determined, whose change is equivalent to the dimensions of the real solid.

Experimental data on influence of conditions of high-strength steel crystallization on its mechanical properties are given in the work. Special attention is paid to the cold resistance as to the most important indicator of operation properties of the responsible products defining reliability and operability of a cast final product. Serial curves of impact strength, work of crack development and percent of fibration are given depending on test temperature. The possibility of increase in cold resistance of the cast alloyed steel is shown depending on casting technology: in a volume sandy form (control casting), in a thin-walled form with the ceramic layer and compulsory cooling with air-and-water mix differentiated on height (with external cooling) and in the same form with input of microrefrigerators when filling liquid steel (with complex impact). According to the research results it was established that the impact strength of the experimental metal obtained at complex impact on the hardened metal is higher in all studied temperature interval. Distinctive feature is smoother change nature of impact strength of experimental metal and lack of sharp reduction of this indicator for control samples. Change of work of crack development also depends on conditions of crystallization and cooling of casting metal. Serial curves have shown that tested metal has smaller tendency to fragile destruction (higher cold resistance). Similar dependences are received during the research of break fibration.