The analyses of new solutions to determine the contact stress  in zones with variable frictional forces for upsetting the rectangular strip were executed. It is shown that replacement of the Mises  precise plasticity condition by an approximate condition in terms of  primary stress changes the character of curves contact stresses in  the slip and dead zones, and significantly influences on the dimensions of these zones. It was established that with the decrease of the  friction force at the boundary of the dead zone its width increases.  As a result of numerical analysis of the stress state at the dead zone  dependence of its width from the value of contact shear stresses on  the boundary of dead zone was proposed. Conditions of existence  and sizes of the slip, retardation and dead zones on the contact surface of the deformation region were installed in dependence on friction coefficient and relative width of the strip. Considering distributions of the contact stresses, expressions to determine the efforts  of the upsetting process were found. The results were compared  with known experimental and theoretical data. The estimation of  error calculation effort of upsetting was obtained by the engineering methods.

Description of the program realizing a computational method of  parameters of steel smelting in the oxygen converter with top feed of  blasting is provided in this article. This program was created on the  basis of system of the balance equations solved in unison by method of  iterations. For adaptation of the model the information on structure and  amount of materials, products of melting and duration of operations  which is available in passport data on heats of the BOF shop, is used.  In these conditions when determining structure and amount of slag, the mass of iron in scorification processes can be calculated on an oxygen balance taking into account the common expense of the blasting  recorded by industrial-control system in passports of heats. The program allows to predict melting parameters at change of its starting and  terminating conditions, and also to define value of uncontrollable impacts on process in structured part of the database. At the first stage the  program works out the balance equations. The oxygen consumption  on blasting going for scorification is defined. Then quantity of the oxidized elements is determined and the volume of oxygen for oxidation  is calculated. Further its quantity which went for oxidation of the iron  passing into slag is determined by a difference of the common amount  of oxygen given on blasting and which went for oxidation of elements.  Later the amount of slag is defined with all slag-forming materials and amount of the oxidized iron at the expense of blasting oxygen. At the  second stage the balance of formation of gases and oxides of iron is  calculated. At the third stage the amount of slag is determined taking  into account the consumption of each material. At the fourth stage the  amount of the received metal is calculated. At a terminating stage the  mass and heat balance is formed (how many heat came, how many it  was allocated in the course of elements oxidation and how many of it  was left with the gas heated to temperature of metal, slag). The heat  balance is considered according to ambient temperature that allows  considering reference heat effects for chemical reactions. The mass  and heat balance were adjusted on metal temperature at the end of  blasting.

The analysis of slab forming processes under different schemes:  in rolls (RBE scheme), presses (UOE scheme) and stepwise forming  (JCOE scheme) shows that domestic and foreign plants of large-diameter pipe production for laying offshore pipelines use JCOE scheme.  The mathematical modeling of processes of plastic deformation of slab  in edge-bending press by JCOE scheme and on the stepwise forming  and calibration press of welded O-shaped pipe billet on a mechanical expander was made using the Deform 3D software. The results of  mathematical modeling of stress-strain state of the metal in pipe billets  and finished pipes are considered for all the technological production  process of large diameter pipes. It is shown that the plastic state of the  molded J-shaped slabs on forging equipment and at pipe calibration  is characterized by uneven stress-strain state (SSS) of the metal. Numerical results of the distribution of equivalent stress and strain rate on  the outer surface of the pipe of the size Dt × Sm  =  720×22  mm of K56  strength class have shown that pipe sections with more uneven SSS  have high values of residual stresses and strains, so in these areas was  noted an increase of diameter and roundness of the pipe relative to the  average. The results of experimental research of residual stresses in  pipes after expanding made at TESA 1020 and TESA 1420 confirm the  unstable distribution of stress-strain state in the cross-section of large  diameter pipes. In the weld joint σres reaches a value of +220  MPa  (JOE scheme) and +150  MPa (UOE scheme), which is (0.3  –  0.4)σt ,  whereas in the pipe metal σres  =  +40...45  MPa. Numerical calculations by the FEM model of out-of-roundness of pipe after expansion at various initial geometrical dimensions of the molded slabs are confirmed  by physical measurements of geometric dimensions on the installation  of automatic control. The modeling results have established that for the  construction of underwater gas pipeline according to normative documents the optimal geometric pipe shape and dimensional accuracy of  the inner diameter of large-diameter pipes can be achieved at expanding of the pipe billet with out-of-roundness of 5  mm. This ensures the  quality assembly and welding of the edges of connected pipes in the  pipeline. The results of computer simulation by the FEM model of the  stress-strain state of the plastic forming of pipe billet at manufacture by  JCOE scheme should be considered in the calculation of technological  parameters of pipe billet molding, tool calibration and press equipment  setting modes.

 Using the method of electronic microanalysis, it has been established that in magnetite ores magnetite crystals, depending on the  temperature-time conditions of natural ore formation, have different  microstructure. So in the composition of sedimentary-metamorphic  ferruginous quartzites and magmatic skarns, magnetite crystals have a homogeneous structure and are close in composition to stoichio metry.  In the Kovdor deposit, magnetite crystals have a heterogeneous structure, in the matrix of crystals of which the isomorphic impurities of  Al,  Mg, Ti, etc. exist as separate spinel microphases. When the crystals of  Kovdor magnetite are restored under conditions close to agglomeration, it is established that in the process of agglomeration, crystals of  a heterogeneous structure are destroyed with the formation of two ore  phases: solid solutions of magnetite and wustite that do not participate  in liquid-phase hardening of agglomerates. At the final stage of production of fluxed agglomerates, calcium silicate bonds (melilitic composition) with low strength properties are formed in the composition of  the finished product at the melt site. In accordance with the results of  the present study, the physical and chemical processes of hardening of  fluxed agglomerates using magmatic ores of different genesis it is suggested, when buying iron ore deposits, to pay attention not only to the  content of iron oxides and silicon in the ores, but also on the structural  features of crystals of magnetite itself. At the same time, there are a  number of magmatic ore occurrences in which the magnetite crystals  have a heterogeneous structure.

At large-scale iron and steel enterprises compressed air is generated at CHP (combined heat and power plant) – blowing house, that generates heat and compressed air to the needs of industry. Electri city and  heat are generated at steam turbine plants (STP, cogeneration units). As  a general thing a single-stage compressors and compounded steam turbine driven compressors are used to compress air. If using compounded compressors air cooling is conducted only before the se cond stage  to reduce energy costs/consumption. In order to get that done heat exchangers are used and water is a cooling medium/heat-transfer fluid.  Water temperature is reduced with the help of atmospheric air after  heat exchangers in cooling towers. Decrease of temperature after heat  exchangers is conducted in cooling tower by atmospheric air. Air of  environment temperature goes to the compressor first stage. Putting to  use this system, the temperature of cooled air before compressor stages  depends mainly on environment temperature not to give an opportunity to decrease air temperature before compressor stages to required/ desired values, particularly in summer. In this paper there is a power  cycle at CHP (combined heat and power plant) – blowing house of iron  and steel enterprise, where in addition absorption thermotransformer  as refrigerating machine has been used (AbTT). Extraction steam of  power turbine is used to drive AbTT. In this power cycle AbTT is used  to decrease air temperature in the inlet of the first and second compressor stages. Thermodynamic effectiveness of the newly developed  system has been performed. Total fuel consumption at CHP (combined  heat and power plant) – blowing house has been taken as a performance criterion with all else being equal. Functional connections to  determine the change of total fuel consumption for power, heat generation and compressed air with AbTT in compare with the original one  are presented. This estimation has presented that the use of AbTT gives  the possibility to reduce air temperature before compressor stages by  10  °C and total overall fuel consumption in terms of reference fuel by  0.15  ton of reference fuel/h.

 The article describes the development carried out within framework of the state program, which provides development of industrial  enterprises, including enterprises of metallurgical cycle. Such enterprises are complex plants and associations of vario us scales whose  production has important strategic significance. For reliable functioning of metallurgical enterprises, the adequate power supply system  with high energy efficiency and minimum possible power consumption is required. Most receivers of metallurgical production belong  to the first category of reliability of electricity supply that makes  high demands on their power systems. The power supply systems of  metallurgical companies are considered. It is shown that the power  supply system may be affected by various negative factors, including the switching overvoltages. Such overvoltages can have high frequency character and occur when triggered vacuum swit ches. Their  appearance is caused by the arc interruption mechanism in vacu um  (arc reignition, current chopping, voltage escalation). Overvoltages  reduce level of reliability of power supply systems that can lead to  long outage of responsible consumers. Most vulnerable to overvoltages elements of power supply systems are electric motors whose  isolation has the smallest margin of electric strength. Typical means  of protection (spark-gapped arresters, metal-oxide surge arresters,  spark gaps) are ineffective for limiting the overvoltages with high  frequency character. To limit overvoltages of this kind protective RC  circuits are increa singly used. However, their application must be accompanied by fairly accurate simulation, because the wrong choice  of their parameters can lead to deterioration of switching process. All this causes importance of the problem of choosing the optimal  parameters of protective RC circuits and their connection schemes.  The typical power supply scheme was identified and simulation of  the switching overvoltages arising in the similar scheme was carried  out. MathLab package was applied to build the model of a fragment  of the power supply system. Du ring crea tion of the model there were  used already known provisions and provisions for the first time offered by the authors that provide the larger accuracy to the mo del.  The received results are presented in the form of oscillograms and  comparison of experimental and calculated data was performed. The  relative error of the results was less than 5  %. The recommendations  for the construction of rational power supply systems of metallurgical companies allowing to reduce negative disturbances, acting on  the such systems are given.

In physical metallurgy practice the analysis of phase and structural transformations often is made through the methods based on measurement of magnetic characteristics of metal body; in these methods  measurements of coercive forces, Curie points, the analysis of frequency dependence of magnetic properties and Barkhausen effect are used.  In this paper, the technique based on change of magnetic permeability  of the sample at its continuous cooling from temperatures above Curie point (Tc ), through the martensite transformation start temperature  (Ms ) to the final stages of transformation (Mf ) is applied. The method  essence consists in measurement of frequency fluctuations in oscillatory circuit based on a chain “L (inductance coil, as a magnetic-test  coil) – C (precision condenser)”. Explored metal sample played a magnetic core role in the measuring coil. For supervision of phase transformations effects, the sample was warmed up preliminary and then  quickly transferred to the coil. The main effects were associated with  the transition through the Curie point of ferrite, as well as with the  transformation of austenite into martensite. The measuring scheme has  allowed fixing Curie point of ferrite for various steels in the range of  580  –  780  °С with accuracy of 5  ºС, at the same time martensite transformations interval had extent not less than 100  ºС. It has been shown  that magnetometric analysis technique, based on deviation of magnetic  state of ferromagnetic phases in material at near Curie temperature,  allows to define quantity of δ-ferrite in the mixed structure (martensite  +  δ-ferrite) at its various morphology that is not always achievable by traditional metallographic methods. Magnetometric analysis  of the samples subjected to primary high-temperature quenching and  the subsequent heating on lower temperatures with cooling in the measuring coil unit, has allowed defining temperatures of Ac1 and Ac3 in  studied steels which were in the range of 760 – 1020 ºС. Determination of the point Ac1 for 15Cr13Mn5MoWVB steel (780  –  790  °С) allowed setting the temperature of its tempering after quenching equal  to 780  °С, closest to the temperature of Ac1 , that made it possible to  reduce the rate of decrease in hardness at the subsequent long ageing (up to 3000  hours) of this steel at 720  °С. The developed method  for determining the temperatures Ac1 and Ac3 in steels is additional  to similar methods based on measurements of thermal, dilatometric  and mechanical characteristics and makes it possible to make a more  reasonable choice of these temperatures. The proposed methodology in  the current hardware implementation is applicable only to those steels  where the austenite at its overcooling is sufficiently stable against  processes of decomposition by diffusion mechanism, but undergoes a complete transformation with the aid of the martensitic mechanism  upon reaching Ms and Mf  points (this means that the time of the incubation period at the level of “nose” of the S-shaped decomposition curve  should be not less than 5 minutes); for other steels, including austenitic, carbon and ordinary low alloy engineering steels this technique is  inapplicable.

Steels of various strength classes were distributed and analyzed  according to deformation resistance parameter. It is considered that  the deformation process in the thermodynamic aspect appears to be a  dissipative effect: a part of kinetic energy of the external mechanical  action transfers to the internal energy of the deformable metal with the  formation of a certain dislocation structure. Because of it the energy  criteria were proposed for the deformability of metal, determined in  the standard tensile test. The basis of these criteria is the deformation  work, which was determined by the area of the tension diagram. In this  case, the absorbed energy determines the unit rupture work, and the  rate of energy absorption determines the metal deformation resistance (compliance of plastic deformation). Quantitative assessment of dissipation effect demonstration with matching of the unit rupture work values and the compliance criteria was evaluated. The study was carried  out using standard tensile tests of samples, made of steels with various  strengths, achieved due to chemical composition (alloying) and heat  treatment, used to manufacture products of various structural purposes.  Herewith in the selected complex of steels, the yield strength range  was 210  –  1660  MPa, the ultimate strength was 840  – 1940  MPa. Consequently, it was established that unit rupture work of the concentrated  deformation much exceeds the unit rupture work of the uniform deformation. The criteria of the concentrated deformation compliance  are much lower than the criteria of uniform deformation compliance,  moreover, there is a noticeable correlation between it. The correlation  can be considered as a demonstration of the structural evolution of  metal in both stages of its deformation, in which, in the process of  self-organization of dissipative system, such as deformable metal, the  dislocation density serves as an internal parameter controlling the evolutionary transformation. The correlation between the compliance criteria and the ultimate stresses under uniform deformation and fracture  was established. Thereby, the ranking of steels with different strengths  per energy, absorbed during deformation, was conducted. In the applied aspect, the numerical values of the unit rupture work and the compliance criterion can be used for predicting the behavior of steels of  various strength classes under mechanical treatment and mechanical  action during operation.

The wear resistance of PCD cutting elements of GES 1313  model of E6 in the form of cylinders with a diameter of 13.44 mm  and a height of 13 mm was studied when cutting granite and abrasive  wheels by turning at various speeds, with determining the optimum  cutting speed and obtaining comparative cutting data for Mansurovsky Granite and abrasive wheels of 64C (SiC) grade in order to  develop recommendations on the test conditions for PCD cutting elements. For the characteristics of wear resistance, the ratio of the  decrease in the volume of diamond layer to the volume of the processed material (or the amount of the processed material) was taken  into account for the same degree of wear of the cutting element. In  the first case, the wear resistance was estimated in relative units, in  the second case in cm3 according to the wear of the back surface  in mm. When cutting granite, the cutting speed was changed from  80 to 320  m/min, when cutting abrasive wheels, the cutting speed  was 500  m/min. To calculate the volume of PCD cutting elements 
in the “Compass  3D” program, 3D  models of their worn parts were  designed, a calibration plot of the volume versus the wear size on the  back cutting surface of the PCD was constructed. The cutting angle  was –22°. It was shown that the change in the volume of the worn out  part of the PCD is less than accuracy of the wear pad measurement to  a wear value of 0.8  mm when the cutting angles varies from –20 to  –25. It was found that an increase in the cutting speed from 80  m/min  to 160  m/min while cutting granite in 12  times decreases the wear  resistance of PCD cutting elements; the relative volume wear of PCD  cutters when cutting granite is (0.01  –  0.02)·10–6, which is 20  times  less than at cutting abrasive wheels of 64C grade. The relative wear  resistance of PCD cutters when cutting abrasive wheels of 64C grade  does not depend on the degree of blunting on the back surface to  1.4  mm, this technique can be recommended as an express method  for determining the wear resistance of PCD. The implemented method with the use of “Compass 3D” program or similar engineering  programs to calculate the volume of worn out part of the PCD can  be used to estimate the relative abrasion resistance of abrasive and  cutting materials.

Using the HSC 6.1 Chemistry software package (Outokumpu)  and simplex-lattice planning, the thermodynamic modeling of the  boron equilibrium distribution between iron containing 0.2  % of C,  0.35  % of Si, 0.028  % of Al (in the terms and hereinafter indicated  mass.  %) and slag of the system СаО – SiO2 – Аl2O3 – 8  %  МgO – 4  % В2O3 was carried out in a wide range of chemical composition and at  temperatures of 1550  °С and 1600  °С. Adequate mathematical models in the form of III degree polynomial obtained for each temperature, describes the equilibrium distribution of boron between slag and  metal depending on the slag composition. Mathematical modeling  results are presented graphically in the form of diagrams of composition – boron equilibrium distribution. It is shown that slag basicity  affects on the boron distribution coefficient. Thus, increasing the slag  basicity from 5 to 8 at temperature of 1550  °С reduces the boron distribution coefficient from 160 to 120 and, as a consequence, increase  the boron content in the metal from 0.021  % at LB  =  159 to 0.026  %  at LB  =  121, that is, growth slag basicity is beneficial to the development of boron reco very process. The positive effect of the slag basicity on boron recovery process in the researched range of the chemical  composition can be explained according to the slag phase composition and thermodyna mics of boron reduction reactions. The temperature growth of the metal negatively affects the boron recovery.  Equilibrium boron distribution coefficient increases by an average of  10 units with an increase in temperature to 1600  °C. The diagrams  contain marked field of slag chemical composition with 53  –  58  % of  CaO, 8.5  –  10.5  % of SiO2 and 20  –  27  % of Al2O3 , providing boron  distribution coefficients at level of 140  –  170 at temperature range of  1550  –  1600  °C and allowing to expect boron concentration in the  metal at the level of 0.020  % at LB  =  168  % and 0.023  % at LB = 139  at the 4  % of B2O3 in the slag initial.

Thermodynamic simulation of chemical and phase transformations was made for the system of oxidized manganese ore – carbon.  Prediction of thermodynamic simulation of chemical and phase transformations in the system was carried out using “Astra 4” multipurpose software system designed for simulation of equilibrium states  and processes in high temperature systems with chemical and phase  transformations developed in Bauman MSTU. Calculations of phase  composition and characteristics of the equilibrium were carried out using the reference database on properties of individual substances. The  basis for information in the database of “Astra 4” software complex  are thermodynamic, thermo-physical and thermochemical properties  of individual substances, which were systematized at the Institute of  High Temperatures of USSR Academy of Sciences and National Bureau of Standards of the United States, published in periodicals, monographs, handbooks, and processed and calculated in Bauman MSTU.  The study of simulation of chemical and phase transformations in the  system were carried out in the temperature range of 1573  –  2573  K  with carbon content of 5  –  10  –  15  % in the system and pressure of  0.1  MPa. During the simulation it was found that the maximum transition degree of manganese into kMn5Si3 is up to 95.3  % at T =  1873  K  and 30  % content of reductant in the system, with further increase in  temperature, the manganese begins to move in to the gas phase. Silicon in comparison with manganese, recovers more difficultly, and with  temperature increasing begins to transit into the gas phase, the most  optimal temperature interval of silicon recovery is 1773  –  1873  K with  the content of reductant in the system from 15 to 30  %. The transition degree of iron (αFe ,  %) in the system depending on temperature  and %  content of the reducing agent, allowed to determine the optimal  temperature range of 1773  –  1873  K when the content of the reducing  agent is 15  %. Thermodynamic modeling of phase transitions of the  system manganese ore – reducing agent allowed to perform the opportunity of obtaining ferro-silico-manganese from refractory oxidized  manganese ore of “Western Kamys” deposit by electric smelting.

The analyses of new solutions to determine of the contact stress in zones with variable frictional forces for upsetting the rectangular strip are executed. It is shown that replacement of the Mises precise plasticity condition by an approximate condition in terms of primary stress, changes the character of curves contact stresses in the slip and dead zones, and significantly influences on the dimensions of these zones. Conditions of existence of the slip and retardation zones on the contact surface of the deformation region in depending on the friction coefficient and the relative width of the strip are installed. A method for determining efforts of the upsetting for bizonal and three-zone curves of contact stresses is developed. Comparison of the results with known experimental and theoretical data has done. The estimation of error calculation effort of upsetting by the engineering method is obtained.

The needle structures were observed in the condensate obtained  by heating the galvanized steel in plasma- arc furnace with graphite  cathode in the atmosphere of argon. The research results have shown  that the leading phase in this case is zinc oxide ZnO.