The paper presents the research results of an experimental coal-chemical pitch, obtained on the base of solvent controlled influence (hydrogen donator) on thermally activated organic mass of coking coal. The authors also have defined the main parameters of preparation of such a pitch of temperature, process time and component ratio. The most active process catalyst was selected. The test product according to the quality factors – volatile-matter content, softening temperature, substance portion, which are not soluble in toluene and quinolones, structural characteristics – corresponds to a high-temperature coke-chemical pitch. It is shown that the maximum conversion level and the best application properties according to traditional quality factors for pitch can be obtained on the base of coal concentrate with the largest content of vitrinite and the thickness of a plastic layer. Coal-chemical pitch is suitable as a binder for the production of refractory masses and contains in dozens of times less carcinogenic benzapyrene, as it is obtained directly from coal without the impact of high temperatures, typical for the coking process.

The development of schemes of heat exchange in a blast furnace was considered with the improvement of the blast furnace smelting technology. It was noted that for the estimation of the thermal state of blast furnace as a control object it is expedient to divide it into two thermal zones, upper and bottom. The interface between them is in the top of the mixed recovery between the level of the beginning of the carbon gasifi cation of coke and the horizon, below which iron oxides are directly reduced. Upper slow heat exchange section in terms of heat exchange is reserve height providing better thermal and regenerative operation of the furnace. The bottom section of slow heat exchange should not be used as a reserve for improvement of thermal and reduction work of the blast furnace. It is shown that the presence of two zones of intense heat exchange in the present conditions of smelting of various types of iron ore using the combined blowing of high parameters is a prerequisite for the stability of the course of the blast furnace process and effi ciency of smelting.

The article presents the conclusions and analysis results of three variants of specific cutting works analytical dependences from durable and plastic properties of cut band materials which are characterized by the limit of strength and coefficients of indentation and incision. The conclusions are based on three accepted combinations of cutting effort dependences from relative intromission of knives into the band, thus characterizing periods of indentation and cutting. Combinations of quadratic and linear dependences, two quadratic ones and the use of one of the quadratic dependence in the zone of indentation and in the zone of cutting were investigated. The first variant is considered to be the most acceptable one for engineering calculations. On its base there were received dependences for cutting effort calculation by means of inclined and disk-shaped knives.

The article presents the comparative evaluation of thermal stresses in the capacity of iron-ore pellets with diff erentiated porosity. Thermostressed state of pellets, derived from the use of thermal power wet charge heat-spraying technology for charge skull and palletized materials has been analyzed. The infl uence of porosity, thermal pellets massiveness on the magnitude and nature of the thermal stresses changes along the cross section of the pellets has been set. The authors have evaluated the nature of changes in the strength of the pellets with diff erentiated porosity along its cross section, with the dynamics of the temperature fi eld of the porous spheres and criteria of massive heat in the nucleus and pellet shells. The analysis of the role of thermal stress to activate the sintering of iron-ore pellets has been conducted to propose recommendations for improving the thermal conditions of pellets burning. On the basis of this analysis the authors have concluded that a more favorable pore structure of pellets is produced by forced nucleation technology, in the capacity of which the nucleus with high porosity is formed.

Cooling rate is one of the major parameters of thermal processing. The experiments on the diff erentiated thermal processing by air of rails of R65 type are made on skilled installation to purpose an establishment of microstructure formation rules in a rails heads. In the course of thermal processing the temperature was measured in points characterizing the quality of rails training at acceptance tests at the depth of 10 mm and 22 mm from a surface of a head driving on the central line of symmetry axis of a rail. Metal cooling rate was calculated in the range of temperatures of pearlite transformations. Change dependence of cooling rate of rail metal on air pressure was established. The dependences received during the experiment possess high factor of reliability that allows applying them in forecasting of cooling rate at pressure increase by means of extrapolation.

The paper presents the basic thermomechanical properties of the molding and core mixtures and the factors they depend on. The authors of the work have analyzed the conditions for thermal and dynamic eff ects of melt on the walls of the form during the fi lling and hardening of the metal and their infl uence on the formation of surface defects in the casting. The article also gives the results of deformation dependence of the most common molding sands on the duration of heating when simulating actual conditions of casting formations. The connection of deformation capacity of the mixture with the defects formed on the castings and compliance of molding (core) mixture has been shown. A set of measures to prevent surface defects has been off ered in the paper. It has been established that the formation of scabs, breaks and burnings-on at castings is a consequence of the deformation changes and destruction of surface layers of the mixture. From the point of view of exclusion of surface defects and environmental aspects, the best are sodium silicate and metallophosphate mixtures.

Since the mechanical properties of metals and alloys with ultrafi negrained structure are very attractive from practical appliance one of the technology development approaches is the creation of continuous methods of severe plastic deformation. Implementation of current methods of nanostructuring to existing technological processes of metallurgical and steel wire production involves a number of limitations connected with the size of processed workpieces. The article shows the necessity of developing a method of continuous methods of severe plastic deformation which according to its technical and technological characteristics would be compatible with existing technological processes of metalware manufacture. Combining of diff erent kinds of plastic deformation is a perspective tendency. Carbon wire was chosen as an investigation object. Combination of external stress leads to enhancing the technological possibilities of drawing as the basic wire production operation to large extent. On the basis of combining drawing with bending and twisting new method for obtaining the ultra-fi ne grained structure in semi-product which is protected by the patent of the Russian Federation. The essence of the method is the simultaneous applying deformations of tension when drawing, bending when going through the system of rolls and torsional deformation on a conti nuously moving wire. Various hardware devices and tools already app lied for steel wire production can be used to implement this method thus simplifying its introduction to the current industrial equipment. Schematic diagram and description of the developed method are presented. Photographs of the carbon wire microstructure with diff erent carbon content after diff erent types of deformation eff ects are shown. It is proved that combining drawing with bending and twisting leads to carbon wire microstructure refi nement. It is shown that deformation combined eff ect on carbon wire allows to modify its mechanical pro per ties in a wide range, while matching its high strength and ductility.

The paper is devoted to the research of velocity variation of ultrasound propagation at plastic deformation of corrosion-resistant highchromium steel 40KH13 with ferrite-carbide (as-received condition), martensitic (after hardening) and sorbite (after high-temperature tempering) structures. It has been revealed that each condition demonstrates its own load curve. In as-received condition the load diagram is practically a parabolic one on the whole extent, while in a martensitic condition there is only the stage of a linear deformation hardening, and in a sorbite condition the plastic fl ow curve is three-stage. Using the methods of optic and atomic-force microscopy, the authors have researched the structure of steel at diff erent kinds of thermal treatment. Simultaneously with the regist ration of load curves the researches have conducted the velocity measurement of ultrasound surface waves (Rayleigh waves) in the researched steel at the extension. The realization of the method of velocity variation of Rayleigh waves is in a periodic generation of rectangular impulses with the duration of 100 ns at the input of a radiant piezoelectric transducer and the registration of the passed-by one according to the sample of the wave by means of the receiving piezoelectric transducer, connected up to the digital oscilloscope. The registered signal in a digital form has been used to measure time, passed from the moment of impulse generation at the input of the radiant transducer up to the moment of signal initiation at the output of the receiving transducer. The distance between the transducers during the experiment is constant. It has been shown that the dependence of ultrasound velocity at active loading is defined by the plastic fl ow rule, i.e. the staging of the appropriate loading diagram. The structural condition of the researched steel changes not only the type of the deformation curve at uniaxial tension, but it also changes the dependence character of ultrasound velocity on the deformation.

The temperature and concentration dependences of the electrical resistivity of the nickel-chromium alloys in the liquid state have been studied. Experimental data suggest a nonlinear concentration dependence of the electrical resistivity isotherms of the studied alloys. The results of studies of the temperature and concentration dependencies of the electrical resistivity of nickel-chromium alloys allow determining the optimal conditions for the formation of microhomogeneous and the equilibrium structure of the melt. Using of percolation theory and quasichemical model of microheterogeneous structure of liquid metal alloys gives the possibility to explain the nature of the isotherms of the electrical resistivity of nickel-chromium melts. The process of structure formation of nickel-chromium melts with increasing chromium concentration has been presented in the form of schemes, reflecting the gradual formation of different clusters, featuring by their structure and size.

The article is devoted to the conducting of simulation process of niobium dissolution in iron at electric arc welding. The model is based on the presentation of the nature and diffusion of dissolution of niobium particles in metals. The model includes the diffusion equation, initial and boundary conditions, as well as the motion equation of the media interface. It has been assumed that the value of the diffusion coefficient in the liquid iron is in many times higher than the value of this coefficient in the solid solution. The solution of the diffusion Stefan problem in the fi eld of solid is in the form of Fourier series cosines, and in the fi eld of liquid in the form of the error functions. The result is the dissolution of niobium, which for high temperatures and particle sizes of 10 μm is from 10 s to 100 s.

Using the methods of optical, scanning and transmission electron diffraction microscopy as well as microhardness and tribology parameters measurement the authors have established the changes regularities of structure-phase states, defect substructure of rails surface after the long term operation (passed tonnage of gross weight of 500 and 1000  mln. tons). It has been shown that the wear rate increases in 3 and 3.4 times after passed tonnage of gross weight of 500 and 1000 mln. tons, accordingly, and the friction coefficient decreases in 1.4 and 1.1 times. The cementite plates are destroyed absolutely and cementite particles of around form with the sizes of 10–50 nm are formed after passed tonnage of 500 mln. tons. The appearance of dynamical recrystallization initial stages is marked after the passed tonnage of 1000 mln. tons. The possible mechanisms of established regularities have been discussed in the work. It has been noted that two competitive processes can take place during rails long term operation: 1. process of cutting of cementite particles followed by their carrying out into the volume of ferrite grains or plates (in the structure of pearlite); 2. process of cutting, the subsequent dissolution of cementite particles, transition of carbon atoms to dislocations (into Cottrell atmospheres), transition of carbon atoms by dislocations into volume of ferrite grains or plates followed by repeat formation of nanosize cementite particles.

The process of zones formation in the layer was investigated. A new research method was developed for the saturation zone in the layer by discharge of sintering bowls with the structure conservation. Sintering mixture was pelletized using of melt paraffin instead of water. The destruction of the granules in areas with a dry charge material above the zone of saturation forms a zone of fine fractions with a height of about 6 mm with low gas permeability. Zone of fines increases the pressure loss in 1.4 times and the shrinkage of the layer – by 20–25 mm. Fines form a channel course of the gases in the zone of saturation clogging the channels with a diameter less than 0.6 mm. Negative impact on the permeability of the destruction layer of the pellets in the drying zone – intensive heating zone – and the saturation zone should be reduced to improve the efficiency of the sintering process.

The problems associated with the study of stress-strain state of the metal and efforts on the mill for rolling the balls of large sizes are considered. Implementation of the proposed measures allowed the balls of high-quality with a diameter up to 125 mm to be rolled.