The creation of strong structural materials allows the production of rod parts such as shafts and axles with a smaller cross section. Strength in this case is maintained, and rigidity decreases, since a thin and long rod has low stability under the action of a longitudinal force and a small bending stiffness due to a transverse load. The small bending stiffness of the rod parts causes significant problems in their processing and assembly, therefore such parts are usually non-technological. Deformation hardening of long-length small-rigid shafts and thin-walled cylinders causes deformations and deflections, for prevention of which one must sacrifice the productivity of the technological process. Flexural rigidity of long parts depends on loading conditions, product geometry and physical and mechanical properties of the material. In real constructions, when the loading conditions and geometric parameters are specified, the rigidity of the products can be changed only by varying the physical-mechanical properties of the material. If a concrete material is specified, only the elastic modulus (E or G) remains to control the rigidity. However, it has been established in a number of studies that the modulus of elasticity does not practically change under ordinary temperature-force conditions. Therefore, at present, the rigidity of the product can only be increased by constructive measures. In the present work, the possibility of increasing the flexural rigidity of cylindrical calibrated bars due to the formation of technological residual stresses is considered.As a result of the experimentalstudies, the effect of the main calibration parameters on the magnitude and nature of the residualstress distribution was established. The obtained curves are used to simulate the flexural rigidity of calibrated bars, depending on the degree of relative reduction and the basic geometric parameters of the working tool (drag). It was established that an increase in the degree of relative reduction and the length of the calibrating zone of the dies has a positive effect on the rigidity of the rod products with an increase in the angle of the working cone of the tool the bending stiffness of the bars is reduced.

Meeting the challenges of the world’s oceans development, especially in the Arctic regions, in the first place, it is absolutely necessary to build a modern fleet, nuclear icebreakers, Arctic cargo ships, gas carriers, stationary and floating drilling structures and offshore platforms, underwater complexes that provide oil and gas production on the continental shelf; to reconstruct coastal areas; and to build harbors, that require a large number of cold-resistant high-strength weldable steels to reduce metal consumption in engineering structures. That’s why the Russian government motivates construction of the shipbuilding complex “Zvezda” situated in the Far East (which is the largest national and world-wide shipyard). Vyborg Dockyard and Severnaya Verf (Northern Shipyard) in St. Petersburg are being modernized. The creation of new steels with minimum alloying and unified chemical composition to enable the development of more economical technologies for welding and assembling such unique vessels and marine technical structures is an urgent task. The paper deals with the issues of formation of the low-alloy steel structure with variable nickel content during the plastic deformation process. The specimens taken from three experimental melts of different chemical composition with varying nickel content (0.5  %, 1  %, and 2  %) were investigated. Selected steels were tested by means of Gleeble 3800 imitating thermomechanical treatment with various temperature parameters of the finishing rolling stage and accelerated cooling up to the predetermined temperature. Mechanical properties were determined. The paper presents results of structure examination by means of optical metallography as well as crystallographic analysis of microstructure using scanning electron microscopy (EBSD analysis). It is demonstrated that the scheme of thermal-deformation effect should depend on the alloying level, i.e. the final structure of steel (ferrite-bainitic, bainitic or martensite-bainitic). The most effective strengthening in steels with a ferrite-bainitic structure is obtained by formation of low-angle boundaries in the α-phase during the plastic deformation. Steels with bainitic structure are not likely to be significantly strengthened by changing of deformation temperature parameters at the finishing stage of thermomechanical treatment. Conditions providing the formation of additional low-angle boundaries were not found in martensite-bainitic steels, which might be the subsequent effect of polymorphic transformation by shearing.

The most economical way of producing steel H-beam profiles of wide assortment is the rolling on modern universal rail-beam mills equipped with continuous and reversible groups of stands with fourroll universal beam calibers. They are effectively used in the foreign metallurgy for the production of rails and beams. In Russia, the first two such mills are constructed and are currently being developed at the EVRAZ ZSMK (Novokuznetsk) and in the Chelyabinsk metallurgical plant. The proposed new method of calculating the roll pass design for universal rail-beam mills is based on the results of the statistical generalization of existing technological rolling modes of H-beam profiles on the universal beam, rail-beam and section mills equipped with universal stands, as well as on authors’mathematical model of metal forming by rolling in universal calibers based on variational principle of minimum total power. At the analysis and generalization of existing technological rolling modes of H-beam profiles a statistical sample was formed that includes the main characteristic parameters of calibration: number (N) and H-beam profile type, the number of passes (n), average reduction ratio in each pass (λi ), the total (common) reduction ratio (λΣ ) for “n” passes and distribution reductions ratio at the passes. The total volume of the sample amounted to 472 points, received at 55  rolls calibrations. Generated sample was investigated using correlation and regression analysis. As a result, regression dependences were obtained for calculation of basic characteristic parameters of calibration. With the application of the developed method roll pass design have been calculated for the finishing rail tandem of universal rail-beam mill for rolling 35B2H-beam. Characteristic features of the obtained mode are almost the same reduction ratio of the neck λш and flanges λф during rolling in every universal caliber and the difference of values λш and λф in passes are 0.4  –  2.4  %, i.e. uniform deformation of the metal is achieved along the profile elements, which contributes to a high quality H-beam.

The round steel beam is widely used in metallurgy, mechanical engineering, construction and is one of the major players in the engine industry. Having the excellent anti-corrosion properties, combined with a remarkable strength, the round steel beam is often indispensable in the production of the various mechanical machines and devices. The cylindrical springs for the railway and motor transport are made from the round beam with the help of the special bending machines. Billets from the round beam are also used in the metallurgy at the manufacture of seamless pipes for the oil and gas industry. The rollers of the sheet-straightening machines and rolling mills in metallurgy have the form of stepped round beam. The steel construction armature is made from the round beam and is close to it by geometric dimensions. The main foreign producers of continuous-casting-billets machines for production of round-cross-section blanks are SMS-Demag (Germany), Danieli (Italy), SMS Concast (Switzerland) and Siemens VAI (Austria). The modern production of round steel beam has place on many Russian metallurgical plants, for example, on JSC “Chusovskoy metallurgical plant”, PJSC “Chelyabinsk metallurgical plant”, JSC “Volzhsky pipe plant”, OJSC “Nizhneserginsky metizno-metallurgical plant”, JSC “Chepetsky mechanical plant”, PJSC “Seversky pipe plant” and PJSC “Taganrog metallurgical plant”. In manufacture of articles from round beam and under their exploitation, they often have an elastic or elastoplastic deformation of bending or have a complex deformation of torsion with bending. The analytical method for determining residual curvature of round steel beam under elastoplastic bend is proposed in this paper. The calculations allow us to determine residual curvature of round beam after bending and the bending moments of beam’s cross section at bending depending on the beam’ radius, elastic modulus, yield stress and hardening modulus of beam’s metal. The research results can be widely used at engineering and metallurgical plants.

A new method of calculating the roll pass design for universal rail-beam mill based on the results of statistical generalization of existing technological procedures rolling H-profiles and on the application we have developed a mathematical model of metal forming during rolling in the universal grooves.

With the application of the developed method have been calculated roll pass design of the finishing train tandem of universal rail-beam mill for rolling I beam 35B2. A characteristic feature of the regime are obtained almost the same reduction ratio of the web  and flanges  during rolling in every universal groove: the difference values  and  are 0,4-2,4%, ie uniform deformation of the metal is achieved along the profile elements, which contributes to a high quality I-beam.

Physically observed mechanisms of transition from reversible deformation to irreversible do not have an adequate mathematical model in the mechanics of a deformed solid. An attempt is made to describe the observed phenomena on the basis of the energy principles of mechanics. Two models are considered, the first of which provides for a two-stage picture of a uniform strain with linear stretching of a homogeneous sample with isotropic properties. At the first stage, the generally accepted equations of motion in the form of Lagrange are used, the relationship between longitudinal and transverse deformations determines the Poisson’s ratio. After reaching the critical state, the deformation remains uniform with the equations of motion similar to those adopted in the first stage, but the ratio of transverse and longitudinal deformations varies, facilitating the return of the volume of particles to their original value. In this case, the energy of the particles, determined by the change in their volume and shape, decreases, the excess part is released as heat to the surrounding space. In the second model, the material of the deformable body is assumed to be an ideal rigid-plastic medium, for which the initial undeformed state becomes plastic when the tangential stresses reach a critical value. The position of the shear planes is determined from the extreme principles of the theory of plasticity. The most probable is sliding along planes, the normals to which are oriented at an angle of 45° to the axis of maximum normal stress. It is shown that, due to the change in the stress state scheme after the formation of primary slip bands, several other families of slip planes can be successively formed. Moreover, a shift in the second, and then in the third and other families, requires less energy. But the simultaneous existence of several slip planes is impossible, since a reduction in effort leads to the termination of sliding along the initial plane. Thermal sources on slip planes result in energy dissipation, reduction in effort and further development of deformation requires an increase in effort to a critical value corresponding to the beginning of the first stage. Both models are consistent with the experimentally observed mechanisms of irreversible deformation, in particular when static stretching under the conditions of planar deformation, fracture of samples most often occurs at an angle of about 21°.

The literature presents contradictory data on the microsegregation of silicon in cast iron. Authors of the previous works have investigated silicon microsegregation in dendritic cell consisting both of primary austenite and eutectic austenite that grows on the primary austenite dendrites. Since the silicon content in austenite affects the temperature and completeness of the phase transitions during cooling and heat treatment, the absence of data on silicon microsegregation do not allow to predict the microstructure of cast iron in the as-cast condition and after heat treatment. The silicon microsegregation in gray cast iron with composition Fe  +  3.11  %  С  +  1.6  %  Si  +  0.4  %  M n by the energy dispersive X-ray spectroscopy and calculation of the nonequilibrium solidification in the Thermo-Calc software were investigated. The silicon microsegregation in the primary austenite is not observed. The silicon content in the primary austenite was ≈2  % that is higher than silicon content in the eutectic austenite ≈1.5  %. Due to the calculations results the microsegregation of silicon in primary austenite are negligible. By calculation the non-equilibrium solidification of ternary alloys Fe – Si – C [Fe  +  1.5  %  Si  +  X  %  C], at X  =  1.5; 2.8; 3.7 it was shown that the only primary austenite solidified at 1.5  %  С and microsegregation of silicon are positive (Si content in the center of the dendritic cells is lower than on its boundaries). For the alloy with 2.8  %  С, the microsegregation of Si in the primary austenite is also positive, however the silicon content in the eutectic austenite, growing on the primary austenite during the austenite-graphite eutectic formation, will be lower and the “rim effect” (maximum Si content at the boundary between primary and eutectic austenite) should appears. At the 3.7  % of C in alloys the primary dendrites amount should be limited, so the major part of the dendritic cell should consist of the eutectic austenite, the Si content in which should be decreasing during the solidification. In this case the so-called negative microsegregation should occur.

The authors have studied the effect of the grain structure, crystal structure and defects of 35KhGF steel samples on the character of temperature dependence of the melt specific electrical resistance at temperatures of 1450–1720  °C. Grain and crystalline structures changed as a result of heat treatment - normalization and tempering. The peculiarities of grain and crystalline structures, the defects were recognized according to the results of metallographic study. The metallographic study was carried out by diffraction of backscattered electrons-EBSD analysis. Scanning areas were chosen with the inclusion of defects in metal of technological origin, namely, microscopic discontinuities filled with gas or slag. The results of EBSD analysis are drawn as IPFpatterns; they show the texture state of the samples using the color assignment method. The microstructure of a 35KhGF steel sample after normalization at 910  °C has the smallest crystallites (of the order of 1  μm) and the largest extent of the grain boundaries. All samples have defects  – discontinuities of the order of 1 μm in size. Specific electrical resistance of molten 35KhGF steel samples was measured by the method of rotating magnetic field in heating mode and subsequent cooling. For samples preliminarily normalized at 910  °C, a discrepancy in the temperature dependences of resistivity and an irreversible decrease in the resistivity temperature coefficient were observed in cooling mode of the melt. The discrepancy between the temperature dependences of the electrical resistivity and the irreversible decrease in the temperature coefficient of the resistivity was analyzed on the basis of the microinhomogeneous structure concepts of metallic melts and the phenomenon of metallurgical heredity. According to the notion of the microheterogeneous structure of metallic melts, the melting of a multiphase steel ingot does not immediately produce a homogeneous solution of the alloying elements in the iron at the atomic level, and a chemically microinhomogeneous state is maintained in a certain temperature range. Looking at the branching of the temperature dependences of the electrical resistivity, the transition of the melt into the state of true solution occurs only near the temperature T*  =  1640  °C. The value of temperature T* according to the notion of the structural metallurgical heredity phenomenon depends on microstructure, phase composition and crystalline structure of the initial sample. The presence of discontinuities leads to appearance of an excess volume of melt during metal melting, which is partially retained during cooling and crystallization. In this case, the temperature coefficient of the resistivity in cooling mode is close to zero in absolute value, even at ingot cooling rates of the order of 10  °C/s the crystallization conditions change, in particular, the metal’s propensity to amorphization increases.

The behavior of materials in different areas of cyclic loading is very different and can depend on both their state and the test conditions. As the criteria for damage during cyclic loading, width of the hysteresis loop, parameters of the dislocation theory, magnitude of the stresses and their intensity, relation with the grain size, etc. can serve. Meanwhile, there is still no general complex mathematical equation reflecting the effect on metal damage during fatigue of such important characteristics of polycrystals as the density or defectiveness, the stress relaxation rate, loading rate, structural and energy state of the material, namely, strength and hardness, and the applied emerging stress-strain state. In the present work, the influence of cyclic loading on failure from the point of view of competition of the loading and relaxation rates of internal stresses with allowance for the spectrum of plastic deformation waves is considered. Depending on the type and loading conditions, a different spectrum of the waves of plastic deformation and fracture is formed under different kinds and loading conditions. It is shown that as the frequency of cyclic loading (strain rate) increases, the voltage rise time decreases, and the voltage corresponding to a certain plastic deformation increases. The intensity of reducing the resistance to material destruction is related to the intensity of damage accumulation. General analytical equations for describing the behavior of the fatigue curves of polycrystalline metals and alloys are obtained, which allow one to represent the influence of the factors of their state in dependence on the influence of the external conditions of cyclic loading. The equation allows to simulate various situations of behavior of polycrystals with fatigue in metals, as well as to analyze the fatigue curves of materials in different states. Since the relaxation rate in polycrystals is the vectorial value = pl.d + p , representing the sum of the vectors of the plastic deformation rate ( pl.d ) and the actual fracture rate p is the nucleation and growth of cracks, then taking this into account, with increasing pl.d with constant total relaxation rate, the rate of destruction will decrease, the fatigue curve will go lower (position). Fatigue curves are constructed for various parameters of the structuralenergy state (Brinell hardness) and density-dependent coefficients.

Fe – Ni alloys are widely used in modern technology. Boron is one of the alloying components in these alloys. Oxygen is one of the harmful impurities in Fe – Ni 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 thermodynamics of the oxygen solution in boron-containing Fe – Ni melts is of considerable interest for the practice of such alloys production. Thermodynamic analysis of oxygen solutions in boroncontaining Fe – Ni melts has been carried out. The equilibrium constant of interaction of boron and oxygen dissolved in the Fe – Ni 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 boron with oxygen in Fe – Ni melts, the oxide phase, in addition to B2 O3 , contains FeO and NiO. Values of the mole fractions of B2 O3 , FeO and NiO in the oxide phase for different boron concentrations in Fe – Ni melts were calculated at 1873  K. In the case of an iron melt at low boron contents, the mole fraction of boron oxide is ~0.1. As the content of nickel and boron increases in the melts, the mole fraction of boron oxide in the oxide phase increases and, in the case of pure nickel, is close to unity. Dependences of the oxygen solubility on the contents of nickel and boron in the studied melts were calculated. With increasing nickel content in melt deoxidation ability of chromium increases significantly. The oxygen solubility curves in boron-containing Fe – Ni melts pass through a minimum whose position shifts to the higher boron content with an increase in the nickel content in melt. Boron contents in minimum points on the oxygen solubility curves and the corresponding minimum oxygen concentrations were determined.

Technology of arc surfacing with flux-cored wire, in which tungsten oxide WO3 and substances containing reducing agents: carbon and silicon are used as fillers, is of interest for implementation in terms of resource saving. Thermodynamic estimation of probability of 21  reactions proceeding under standard conditions was carried out with the use of tabular thermodynamic data for reagents in temperature range of 1500–3500  K. This interval includes temperatures at the arc periphery and in the upper layers of surfacing bath. Among the reactions are direct reduction of tungsten oxide WO3 by carbon and silicon; indirect reduction of tungsten oxide WO3 by carbon; reaction of tungsten combination with carbon and silicon with formation of tungsten carbides and silicides. W, WC, W2 C, WSi2 , W5 Si3 , CO, CO2 , SiO, SiO2 were regarded as possible reaction products. Oxidation reduction reactions were recorded for 1  mole of O2 , and reactions of tungsten combination with carbon and silicon – for 2/3 moles of W. Probability of reactions proceeding was estimated based on the standard Gibbs energy of reactions. As a standard for reagent substances in the range of 1500  –  3500  K, the following states were selected: W(s), WO3 (s,  l) with phase transition at 1745  K, WC(s), W2 C(s), C(s), CO(g), CO2 (g), WSi2 (s,  l) with phase transition at 2433  K, W5 Si3 (s,  l) with phase transition at 2623  K, Si(s,  l) with phase transition at 1690  K , SiO(g), SiO2 (s,  l) with phase transition at 1996  K. To estimate the degree of influence of reactions of possible evaporation in WO3 tungsten oxide arc (Tboil  =  1943  K) on thermodynamic properties, thermodynamic characteristics of two reactions were calculated in which WO3 (g) was chosen as a standard state in the same temperature interval. Thermodynamic analysis of WO3 reduction shows that temperature of melt along with composition of flux-cored wire can affect composition and service properties of deposited layer. In the system under consideration, formation of tungsten, tungsten silicides and carbides is likely at high temperatures of melt (more than 2500  K). The flow of reactions significantly changes composition of gas phase, but not slag phase in surfacing bath. At temperatures below 1500  K, formation of tungsten and tungsten silicides is most likely due to reduction of WO3 by silicon, with the slag phase becoming more acidic due to SiO2 silicon oxide formation. However, this temperature range is below the melting point of WO3 tungsten oxide (1745  K). In the temperature range of 1500  –  2500  K, a number of competing reduction reactions occur, as a result of which both tungsten and its silicides and carbides are being formed in metallic melt. Reactions of tungsten combination with silicon and carbon with formation of silicides and carbides are less likely than reduction reactions. Evaporation of tungsten oxide WO3 in the arc increases thermodynamic probability of reduction reactions occurrence, but more likely at low temperatures.

BOF steelmaking technology is largely determined with processes taking place in the LD-converter reaction zone, which consists of “primary” and “secondary” sub-zones. The “primary” zone is a crater formed as result of supersonic gas stream impact on metal melt sur- face, fulfilled with metal droplets of 0.1  –  2  mm in diameter. Surrounding in the “secondary” zone consists of the large amount of gas bubbles of 0.2  –  4  mm in diameter. The total surface area of droplets and bubbles is by four orders of magnitude larger as compared with the stable metal surface of magnitude larger as compared with the stable metal surface place. This suggests important role of interface phenomena at steel refining processes. The reaction zone structure and its temperature distribution were studied with “hot” modeling method, where molten cast iron was blown with oxygen in transparent quartz crucible. Each blow was accomplished with photo- and cinema filming through crucible wall. Besides temperature distribution obtained material also allowed study of metal bath hydrodinamics directly in blowing zone. The most unexpected result here was the motion trajectory of bubbles in the “secondary” zone. They moved normally to the crater surface, i.e. almost in a horizontal direction instead of vertical float as it was noticed at “cold” modeling with water. This very important phenomenon is caused by surface tension in homogeneity, due to which the bubbles are moved at higher temperatures direction. Surface tension forces in front of and behind gas bubble in liquid with temperature gradient are different. Because contact forces behind bubble are larger as compared that in front, it is pushed out in direction of surface tension decrease. Surface tension inhomogeneity is generated with temperature (up to 1200  °C) and oxygen concentration gradients in the “secondary” reaction zone. Iron-carbon surface tension changes with temperature rise inconsistently. Surface tension increases with temperature rise up to 1550  °C. At reaching 1550  –  1600  °C there is a bend, which after surface tension begin to decrease. This bend point is as higher as lower carbon concentration in alloy gas bubbles and heterogeneous phase’s motion in surface decrease direction starts from 1550  °C isotherm. So it is outward border of “secondary” reaction zone, which separates it from main metal bath. Inside it resulting surface tension forces push gas bubbles and slag particles into accelerating motion with mass of metal melt in horizontal direction to the crater. This phenomenon determines whole steelmaking bath hydrodynamics with oxygen redistribution between molten metal components and hence the steel refining process in general.

Investigations of the friction influence on the shaping of a flat blank are presented. It is shown that the shaping of a flat blank is determined by kinematic scheme of the metal flow. An intermediate kinematic scheme of the metal flow is proposed. It is proved that as the coefficient of friction increases, the «radial» kinematic scheme of the metal flow smoothly changes to «normal». Evaluation of the friction influence was carried out using computer and physical simulation. For computer simulation the DEFORM program complex was used. Plasticine was chosen as the material for the physical simulation of flat blank shaping. When comparing the results of virtual and laboratory experiments, there is almost complete coincidence.