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Understanding the processes that control the formation of precipitates of alloying element, their composition and morphology is important for the choosing of optimal regimes of thermomechanical treatment, providing the required structural state and properties of low-alloyed steels. The use of modern methods of atomistic modeling and ab initio calculations to study the mechanisms and conditions of precipitation depending on the steel composition and temperature is discussed. The enthalpy of formation of Ti, V, Nb carbides and nitrides in γ-Fe was calculated using the methods of the theory of the electron density functional and the temperatures of their dissolution were determined in dependence on the composition of the steel. The results obtained agree with the experimental data and obtained by the CALPHAD method. Calculations of the electronic structure, enthalpy of mixing, energy of effective interactions between atoms of alloying and impurity elements have been performed. It was shown that an essential factor determining the nature of the interaction between alloying elements was the magnetic state of iron. It has been established that the enthalpy of mixing, which expresses the tendency of the system to decomposition, increases with the transition of α-Fe from the ferromagnetic to the paramagnetic state. In ferromagnetic α-Fe energetically, the formation of precipitates of Cu, as well as particles of a mixed composition of Cu‒Al, Cu‒Ni and an ordered phase of NiAl are preferable. It has been shown that precipitates Cu-based can be formed during technological times. The transition of α-Fe to the paramagnetic state results in increase of interactions between alloying elements (the exception is the interaction of Cu‒Cu and Cu‒Ni). As a result, additional combinations of alloying elements appear, the interaction between which lead to the formation of precipitates. At the same time, in γ-Fe, precipitates can be formed only based on Mo and Nb. The role of magnetism in the formation of precipitates and their influence on the γ→α-transformation is discussed. It has been shown that the results obtained make a base for enhancement technologies of high-strength low-alloyed steel production.

Purposeful control of structural state of steel at every stage of technological chain of steel goods production is necessary for elaboration of effective metallurgical technologies. The purpose of the complex of research and theoretical studies was development of ideas on peculiarities of structure formation of various steel grades. Current conceptions about phase and structural transformations in steels with different contents of carbon and alloying elements considered. For carbon and alloyed steels, the results of the study of the structure of perlite formed at different temperatures summarized; morphology, crystallography and defects of crystalline structure of cementite, processes of its fragmentation, coagulation and spheroidization; crystallography of austenite degradation products; evolution of the structure during cold and hot plastic deformation; carbon redistribution processes prior to and during diffusion-controlled austenite decay presented. For low-carbon low-and sparingly alloyed cold-resistant weldable steels generalized results of investigation of structure-formation processes, alloying relationships, temperature-deformation rolling conditions, parameters of quenching and high-temperature tempering with structure, mechanical properties and performance characteristics of steel plates presented. The elaborated complex of scientific and technical solutions based on the studies enabled to master and digitize production technologies at PJSC “Magnitogorsk steel-works” of new generation steel rolled products intended for ship-building, oil and gas industries, automobile, hardware and construction industries. The new systems of alloying steels of various application, methods of the new generation steels production and automated control of technological processes protected by 27 patents of RF, are widely used in the production activity of PJSC “Magnitogorsk steel-works”.

The paper presents comprehensive scientific and technological solutions related to the large-scale production of new-generation rolled steel in an integrated metallurgical plant. The new-generation rolled steel is in the form of a high-duty steel plate, each geometric element of which exhibits a customerspecified complex of physical and mechanical properties. In the linear sections, surface and volume elements are effectively used as geometric elements. The results of research projects aimed at enriching our scientific understanding of the phase and structural transformations in steels are presented. The capabilities of the enterprise production and quality management system employed by the Magnitogorsk Iron and Steel Company are described; this system ensured the transition of the enterprise toward digital, highly efficient technologies for producing metal products.

A new version of the crystallographic theory of martensitic transformation has been developed, where instead of Bain deformation, the deformation of the lattice was performed by a shear along the twinning system of crystals and an additional change in dimensions in three mutually perpendicular directions. In the proposed variant, the angle of relaxation rotation of martensite crystal was about 1.8°; in the standard phenomenological theory, it was 10°. The new version made it possible to establish the mechanism of lattice deformation upon martensitic transformation, to determine the angle of relaxation rotation, and to carry out crystallographic analysis of martensitic transformation in various alloys. The formation of crystals (laths) of dislocation martensite in medium-carbon steel was found to occur with redistribution of carbon.

An experiment is performed for explosive convergence (collapse) of a cylindrical shell of low carbon steel with a ferrite-perlite structure. It is revealed that during ultra-rapid heating caused by high-speed deformation austenite formation occurs in an unusual sequence: first, free ferrite is converted, then pearlite. The decrease in free ferrite transformation temperature is explained by action of high pressure, as well as by varying degrees of heating steel structural constituents. An effect of barothermal quenching is observed, as a result of which a pearlite-martensite structure forms.

This article presents a review of current results of theoretical and experimental studies of the specific features of the structure that is formed in high-strength low-alloy steel in the process of hot rolling and which determines the properties of the steel. The current concepts of the physical processes that are developed at different stages of a thermomechanical treatment depending on the temperature–strain-rate regimes and chemical composition of the steel are considered. Particular attention is paid to the problems of the formation of the structural state that continue to be debated. The simulation methods of different scale level used to solve the problems of controlling structure formation at all stages of thermomechanical processing process are discussed.

It was shown in the work using electron back scattering diffractions analysis that when cooling lower than temperature of the martensitic fcc-hct transformation in the alloy In - 4.5 wt% Cd a packet structure is formed consisting of colonies of tetragonal lamella plates. At the next packages there are always three grades of the plates of a tetragonal martensite which are in twinning situation and differing with the direction of the tetragonality axis. Each martensitic plate consists in turn of a set of more shallow submicrotwinning plates alternating in the direction of an axis of tetragonality. On the basis of the obtained data it is possible to conclude that the structure of the package consisting of twinning plates and the structure of the separate martensitic plate consisting, in turn, of submicro-twins submits to the general regularities. At each structural level in group of the neighboring areas the building blocks of three grades differing with the direction of a tetragonality axis are found.

Electron back-scattering diffraction shows that a package structure consisting of colonies of tetragonal lamella plates is formed when cooled below the temperature of the martensite fcc→fct transformation in the In–4.5 wt % Cd alloy. On the basis of the data obtained, it can be concluded that the package structure consisting of twin plates and the structure of a separate martensite plate consisting, in turn, of submicrotwins obeys general laws. At each structural level, in the group of neighboring regions, structural elements of three types, which differ in the direction of the tetragonality axis, are found.

In this paper we continued a metallographic study of a number of old products produced in the Urals in the early 18th century, i.e., in the period of transition from handicraft damp-blow technology to blast-furnace production of cast iron and two-stage process of iron and steel production. The results of the study of the microstructure and chemical composition of cast-iron products of the Kamensk cast-iron and iron-works plant, as well the features of their production have been presented and discussed. This paper is attributed to the field of archeometallography.

This paper presents the results of research on the effect of extreme impacts on metals and alloys. This research was performed over the last 25 years in the physical metallurgy laboratory of the Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences. For the purpose of this study, the following extreme impacts are considered: strong magnetic fields, laser heating, shock-wave loading, severe plastic deformation by dynamic channel-angular pressing and shear under pressure, and frictional surface treatment by dry friction.

In this paper, we have continued a metallographic study of a number of old articles produced in the Urals at the beginning of the 18th century, i.e., during the transition from manual to factory production. The results of studying the microstructure and the chemical composition of articles made of iron and carbon steel at the Kamensk foundry and ironworks, as well the features of their production have been presented and discussed. This paper relates to the field of archeometallography.

The ab initio computer simulation of lattice parameters and local structure distortions caused by interstitial carbon atoms in the iron-carbon system has been carried out using WIEN2k software. For the calculations, the full-potential method of linearized augmented plane waves (LAPWs) taking into account the generalized gradient approximation of PBE–GGA was used in a supercell of 54 iron atoms with periodic boundary conditions. The carbon dissolution energy has been found to be 0.85 eV for bcc iron, and 0.79 eV for bct iron. The carbon–carbon interaction energies in the ferromagnetic bct iron have been calculated. It has been found that accounting for tetragonal distortions considerably changes the interaction energy of carbon atoms in comparison with that of the bcc iron. Both the maximum degree of tetragonality of iron and the maximum attraction of carbon atoms have been observed for the case of carbon atoms placed in octahedral pores of the same type. If carbon atoms are in different types of octahedral pores, the tetragonal distortion of the lattice is weak. The obtained results are in good agreement with the Zener–Khachaturyan hypothesis and experimental data of Kurdyumov.

The literature data on the interactions between carbon atoms and the methods of calculating its activity in the γ-iron lattice have been analyzed. Both statistical thermodynamic results and the data obtained by methods of computer simulation have been considered. To compare the available results, the simulation of the carbon activity in austenite using the Monte Carlo method has been carried out. It has been shown that the experimental curve of the concentration dependence of the carbon activity can be reproduced using a large number of strongly differing energies of interactions between carbon atoms in the first two coordination shells. Thus, the problem of determining the parameters of the С–С interaction in fcc iron according to the data on the activity is mathematically ill posed and first-principles calculations are necessary. It has been shown that, at carbon concentrations of up to 7 at %, the approximate statistical theories lead to accurate results. An analysis of the results of an ab initio simulation showed that the inclusion of the interaction between carbon atoms in the third and fourth coordination shells hardly affect the carbon activity.

Exact orientation relationship for martensite transformation in medium-carbon 37KhN3A steel with lath martensite are determined. The mechanism of deformation during the transformation of martensite in steel is described.

Methods of metallography, scanning electron, and transmission electron microscopies were used to study the structure of two pipe steels (without vanadium and with 0.03% vanadium) subjected to γ → α isothermal transformation at temperatures of 400–600°C (initial structure) and tempering at 600–650°C. It has been found that the addition of 0.03% vanadium intensifies the process of the precipitation of ferrite and contributes to the formation of a granular structure. It has been shown that, in high-strength pipe steels with 0.03% vanadium, which have bainitic granular-type structures, the effect of the precipitation strengthening is effected upon subsequent high-temperature tempering at 600–630°; the addition of vanadium leads to an increase in the hardness by 16 HV. In the presence of bainite of the lath type in the initial structure, the subsequent tempering leads to a softening associated with the processes of the recovery, polygonization, and initial stages of recrystallization in situ, which develops at temperatures above 640°C. It has been found that the hardness of the steel without vanadium upon additional tempering decreases regardless of the morphology of structural constituents in the initial structure.

Based on X-ray diffraction studies of the martensite texture in a single martensite packet, exact orientation relationships between the orientations of martensite crystallites and the original austenite single crystal in medium-carbon steel 37KhN3A have been determined to be as follows: (011)α||(1; 0.990; 1.009)γ to an accuracy of \( \pm 0.15^\circ ,{\left[ {01\overline 1 } \right]_\alpha }||{\left[ {1;1.163; - 2.133} \right]_\gamma }\) to an accuracy of ±0.15°. It has been shown that the orientation relationships proved to be almost the same as in the Fe–31% Ni alloy with a twinned martensite with close lattice parameters. Therefore, the conclusion has been drawn that the mechanism of the lattice deformation upon the martensitic transformation is the same in both alloys. It is described as follows. The lattice deformation occurs by shear on the (111) plane in the \({\left[ {11\overline 2 } \right]_{_\gamma }}\) direction and is accompanied by an additional change in the dimensions in the mutually perpendicular directions \({\left[ {11\overline 2 } \right]_{_\gamma }},\left[ {111} \right],\;and{\left[ {1\overline 1 0} \right]_{_\gamma }}\). The invariantlattice deformation is implemented by slip in martensite on the planes of the (112)α type in the direction \({\left[ {\overline 1 \overline 1 1} \right]_\alpha }\). One of the 24 crystallographically equivalent variants of the transformation mechanism has been considered. Apart from this type of deformation, an additional deformation of martensite is possible that does not change its orientation. It has been shown that the orientation of the martensite crystallite calculated via the phenomenological theory of the martensitic transformations (PTMT) differs by approximately 1° from the experimentally determined orientation. This refers to both the lath and twinned martensite. In the twinned martensite, the invariant plane obtained in the PTMT calculations and the habit plane coincide. In lath martensite of 37KhN3A steel, the invariant plane of the martensite crystal obtained in PTMT calculations deviates by ~25° from the orientation of the surface of the martensite plate (habit plane), which is close to the (111)γ plane. An explanation of this phenomenon is given.

The historical aspect is provided for research into the effect of a magnetic field and a number of other actions on martensitic transformation in steels and alloys.

The structure was studied and the texture formation process was investigated in tapes made of Cu–Ni–Me ternary alloys (Me = Fe, Cr, V, or Mn) during cold deformation by rolling to a degree of ∼99% with subsequent recrystallization annealing. It was shown that it is generally possible to create a perfect cubic texture in a thin ribbon made of ternary alloys based on copper and nickel to which a period 4 d-element (iron, chromium, or vanadium) was added. This makes these tapes promising as substrates in the technology for producing second-generation high-temperature superconductor tapes. The optimal annealing conditions were determined, under which, in the studied alloys, a perfect biaxial near-single-crystalline texture can be obtained with a content of cubic grains {001}〈100〉 ± 10° on the surface of the textured ribbon of above 99%.

The effect of a magnetic field on martensitic transformations, which is satisfactorily described by the Krivoglaz–Sadovskii formula, has been analyzed taking into account the nonequilibrium of the martensitic transformation, the possible adiabatic conditions, and the magnetostriction of the paraprocess in ferromagnetic austenite.

Results have been presented for studies of the microstructure and chemical composition of a number of articles made of iron and cast iron at the Kamensk plant, which cover the period from the start of the production of iron on the territory of the city of Kamensk-Ural’skii at the turn of the 17th–18th centuries to the beginning of the 20th century. Differences in the composition of the Kamensk cast iron and modern grades of foundry cast iron have been established. Possible sources of technological difficulties and production waste at the Kamensk plant have been revealed. The potential of metallographic studies for the attribution of historical articles made of ferrous metals are shown.

The role of weakened surfaces parallel to the plane of rolling in the formation of delamination cracks in the course of impact-toughness testing of steels with the bcc structure subjected to high-temperature thermomechanical treatment has been theoretically substantiated. A mechanism of increasing impact toughness during the formation of delamination cracks has been described using 08Kh18T1 steel as an example. It has been shown that the stress state that arises in a material with weakened surfaces can be modeled using composite specimens.

Features of the microstructure and mechanical properties of fine-lamellar pearlite, a bulk nanomaterial, are considered. It is shown that the material possesses unique properties.

The martensite structure of a hardened pseudosingle crystal of grade 37KhN3A medium-carbon structural steel (0.37 wt % C, 1.50 Cr, 3.0 Ni, 0.33 Mn) had the form of coarse packets with dimensions of to 1 cm in the cross section. Every packet was composed of six-orientation martensite crystals arising on one common austenite plane of type {111}. The position of three texture maximums was determined using an X-ray diffractometer for every orientation. In addition, the position of four maximums of retained austenite was found. The periods of martensite lattices and retained austenite as well as the carbon concentration in martensite lattices and near the boundaries are determined.

The structure of strips produced from the Cu–1 wt % Y binary alloy using cold deformation by rolling to the degree of deformation of ~99%, followed by recrystallization annealing, as well as the process of texture formation in these strips, is studied. The possibility of forming a perfect cubic texture in a thin strip made of a binary yttrium-modified copper-based alloy has been shown in principle, which opens the prospect of the use of this alloy to produce substrates for strip high-temperature superconductors of the second generation. The optimum conditions of annealing have been determined, which make it possible to form a perfect biaxial texture in the Cu–1 wt % Y alloy with a content of cubic grains {001}〈100〉 ± 10° on the surface of the textured strip of over 95%.

Structure and mechanical properties of rolled plates (20–35 mm thick) of low-carbon low-alloy steel subjected to thermomechanical treatment (TMT) according to various regimes under laboratory and industrial conditions have been studied. Structural factors that favor obtaining high mechanical properties have been established. The retarding action of TMT on softening upon tempering has been revealed. The reasons for the decrease in the resistance to brittle fracture of the steel subjected to TMT, repeated quenching from the temperature of the furnace heating, and tempering have been determined.

The structural and magnetic phase transitions in Ni-Mn-Sn-based alloys have been studied. The temperature dependences of the martensitic and magnetic phase transformations in Ni51 − xMn36 + xSn13 alloys (0 ≤ x ≤ 4) have been determined in the case where manganese atoms substitute for nickel atoms. For the studied alloys, the concentration phase diagram has been constructed and the temperature regions of the existence of the high-temperature austenite phase L21 and the low-temperature martensite phase in different magnetic states have been determined.

The possibility of obtaining a perfect cube texture in thin ribbon made of binary copper-nickel alloys opens the possibility of using them as substrates in the technology of second-generation HTSC cables. The possibility of production of multicomponent alloys based on a binary Cu-30% Ni alloy additionally alloyed with elements (such as iron or chromium) that strengthen the fcc matrix has been shown. Optimum regimes of annealing have been determined, which make it possible to obtain a perfect biaxial texture with the content of cube grains {001}〈100〉 exceeding 97% in Cu-M and Cu-30Ni-M (M = Fe or Cr) alloys. In the tapes made of copper alloys with iron or chromium, the precipitation of disperse particles occurs in the process of cooling after recrystallization annealing, which improves the mechanical properties of the substrate. The estimation of the mechanical properties of the textured ribbons of binary and ternary copper alloys demonstrates a yield stress higher than that of the ribbons of pure copper by a factor of 2.5–4.5.

We have presented a review of the results of investigating the effect of the cooling conditions and heat treatment on the amount of retained austenite and mechanical properties of commercial steels. Possible methods of obtaining enhanced amount of retained austenite due to the stabilization effect, bainitic transformation, and quenching from the intercritical temperature range have been discussed and analyzed.

We present a review of the results of the effect of external factors on the amount of austenite retained in steels and alloys. Possible methods of reducing the amount of retained austenite via the action of cold treatment, magnetic field, and plastic deformation, as well as the question of the effect of retained austenite on the mechanical properties of commercial and model steels and alloys, — have been discussed and analyzed.

The structure and mechanical properties of 20GL steel are studied. It is shown that a significant decrease in the ductility and impact toughness of the steel is caused by intercrystalline fracture, which is induced by a weakening of the intercrystallite bonds due to the existence of coarse lamellar pearlite and nonmetallic inclusions, namely, film inclusions and eutectic-type oxysulfides, at the boundaries of primary crystals. Annealing from a temperature in the intercritical range is found to improve the mechanical properties.

Polarization pitting corrosion tests are used to investigate the effect of a structure on the corrosion resistance of hypereutectoid U10 steel. In the steel structure, coarse-lamellar and fine-lamellar pearlite forms as a result of isothermal decomposition at temperatures of 500 and 650°C and fine-lamellar pearlite forms during additional annealing at 650°C for 10 or 300 min. The nonequilibrium structure of fine-lamellar pearlite obtained in the process of isothermal decomposition at a temperature of 500°C is found to have the maximum pitting corrosion resistance among the structural states under study.

Magnetic properties and martensitic transformations in the Ni47 − x Mn42 + x In11 alloys (with 0 ≤ x ≤ 2) have been studied. The magnetic-field-induced martensitic transformation was found to be observed for all the alloys. The critical temperatures of magnetic and structural phase transformations, temperature dependences of spontaneous magnetization of austenite and martensite, and the critical field, at which the martensitic transformation occurs, have been determined based on magnetic measurements performed for the alloys under study. The spontaneous magnetization of the alloys in the martensitic state has been shown to be lower than that in the magnetic-field-induced austenitic state by a factor of six.

Results of a chemical analysis of the metal of three antique blades are given, which, based on their chemical composition and the presence of patterns on their surface, can be classified as bulat arms. Alloys that contain 1.5–3.46% carbon have been melted, from which plates with a bulat pattern have been fabricated. The micro- and macrostructure of seven alloys containing 2.4–3.48% C have been studied in detail. The microhard-ness of the structural constituents of these alloys has been determined; the tensile stress-strain diagram of the alloy with 3.02% C has been constructed. The results obtained are compared with P.P. Anosov’s data on bulats.

The phase and magnetic transformations in a ferromagnetic alloy of the Ni-Mn-In system are studied using dilatometry, magnetometry, metallography, and scanning electron microscopy. The effect of a magnetic field of varying intensity on the martensitic transformation and magnetic transitions of the Ni47Mn42In11 alloy is found. It is shown that the linear expansion coefficient and magnetization exhibit an anomalous behavior in the region of the magnetostructural transition.

Peculiarities of the bainite structure formed in low-carbon steel 07G2NDMBT during isothermal austenite decomposition, namely, the sizes of crystallites, their mutual orientation, and the presence of cementite precipitates, are considered. The temperature range of the formation of bainite with the subgrain structure was determined. The size of the austenite grain and degree of hot deformation were found to affect the transformation of bainite that occurs upon subsequent cooling and the submicrocrystalline bainite structure. We studied the structure and mechanical properties of a rolled sheet 16 mm thick, which was subjected to thermomechanical treatment (TMT) under plant conditions in accordance with optimum regimes. It was shown that the high structure dispersion of the steel subjected to TMT is due to not only the formation of bainite with the subgrain structure, but also the partial transfer of crystal-structure defects from hot-rolled austenite to the final bainite structure.

Methods of transmission electron microscopy and EBSD analysis have been used to study the evolution of the structural state of a eutectoid steel in the process of plastic deformation by drawing. It has been established that the reason for steel embrittlement is in the formation in the former grains of the high-temperature phase of a specific element of the structure, namely, a crystallographically oriented colony of products of eutectoid decomposition, including a conglomerate of morphological colonies with a common orientation along the cleavage plane of one of the constituents of the eutectoid. The process of its formation means multiple changes in the scale of the structure and, therefore, increase in the temperature threshold of the material brittleness.

The effect of a high-strength magnetic field on the phase transformations of ferromagnetic materials based on the Ni-Mn-In system with different degrees of alloying has been revealed experimentally. The effect of the chemical composition of the alloys and magnetic treatment on the martensitic transformations and magnetic transitions has been investigated. It has been established that, upon substituting nickel atoms with manganese atoms, the temperature of the martensitic transformation decreases.

Optical metallography and transmission electron microscopy have been used to study the structure of the rolled sheets produced from the pipe steel of Kh90 class. The sheets were manufactured using different technological schemes of strengthening: direct quenching from rolling heating (QRH) followed by high-temperature tempering; and two-step thermomechanical treatment with rapid cooling to a desired temperature (TMT). A relationship between the nature of the structure and mechanical properties of the rolled sheet has been established. It has been shown that the two-step thermomechanical treatment has significant advantages over the quenching from the rolling heating, which is related to the formation of highly dispersed bainite with a subgrain structure upon TMT.

Dilatometry, magnetometry, and optical metallography were used to study structural and magnetic transformations in Ni-Mn-In alloys of different compositions. Temperatures of structural and magnetic transformations of the Ni47 − x Mn42 + x In11 alloys (with x = 0–2) were determined. It is shown that, as the valence electron concentration decreases, the martensitic transformation temperature decreases. Some of the Ni-Mn-In alloys exhibit a ferromagnetic transformation in both the initial austenite and in the arising martensite.

Transmission electron microscopy is used to analyze the evolution of the microstructure of steel 120G4 after complete and partial pearlitic transformation and subsequent heating to 680–1200°C. It is found that, as the heating temperature increases, the fraction of a carbide phase decreases and the character of an austenitic defect structure changes from microtwins and stacking faults to dislocations.

The hardness and wear resistance during sliding and abrasive friction of 80S2 (0.83% C, 1.66% Si) and U8 (0.83% C) steels subjected to the isothermal γ → α decomposition in the temperature range 330–650°C and additional 5-min annealing at 650°C are compared. The optimum decomposition temperature is found to be 550°C. At this temperature, fine lamellar pearlite with the maximum hardness and wear resistance as compared to other pearlitic and bainitic structures forms in the silicon steel. The silicon-alloyed fine lamellar pearlite of 80S2 steel is found to have high hardness and abrasive wear resistance as compared to the similar structure in plain U8 steel; however, this pearlite has no advantages in the wear resistance under conditions of sliding friction on a steel plate. Silicon alloying of the bainitic structures in the eutectoid steel leads to a noticeable decrease in the wear resistance during sliding friction and abrasive action. Friction oxidation is shown to negatively affect the abrasive wear resistance of the silicon steel.

The phase composition and structure of defect portions of pipelines after long-term service in contact with a hydrogen sulfide-containing medium have been investigated. From structural changes, the process of the initiation of cracks and fracture of a low-carbon ferritic-pearlitic steel containing slag-induced laminations and precipitates of sulfides of the (Fe,Mn)S type has been reconstructed. The conditions under which a block cementite substructure is formed in the course of service and a transformation of the plate-type shape of the carbide phase occurs have been analyzed. It has been established that the dispersed carbides precipitating in this case limit the mobility of dislocations and thereby favor degradation of service properties of the pipe steel.

The structural evolution upon high-cycle fatigue (tension with the magnitude of stress in a cycle below the macroscopic yield stress) of the hypereutectoid steel U10 (1.03 wt % C), in which pearlite of different morphology (fine-lamellar, coarse-lamellar, and partially spheroidized pearlite) was formed, has been investigated by scanning and transmission electron microscopy. Based on the fractographic analysis, features of fracture of these structural states have been considered. At a significant distance (10 mm) from the fatigue fracture, features of structural transformations caused by cyclic loading have been revealed. It has been shown that upon high-cycle fatigue in the steel U10 with structures of lamellar and partially spheroidized pearlite, substantial structural changes occur, namely, fragmentation and partial dissolution of cementite plates, and in fine pearlite, additionally, spheroidizing of cementite and polygonization of the ferritic component are observed. A dependence of the character of fracture on the type of structure formed upon fatigue loading has been established. In the steel with a nonequilibrium structure of unannealed fine pearlite, an enhanced elasticity modulus, as compared to other more stable structures (coarse-lamellar, annealed fine, and spheroidized pearlite), and a reduction in the magnitude of the elasticity modulus under the action of cyclic loading have been found. It has been established that the structural changes in fine pearlite of laboratory specimens of the steel U10 upon cyclic tension are qualitatively similar to those in a railroad wheel of the steel 65G under the service conditions.

The transformation kinetics and the morphology of structures formed in the Cu-24 at % Ga alloy at a cooling rate of 1 to 4 × 105 K/s are studied. A massive transformation shows up in the Cu-24 at % Ga alloy at slow cooling rates, and this transformation can be replaced, upon sharp quenching, by a martensitic reaction. The transformation kinetics and the morphology of structures formed in the Cu-24 at % Ga alloy at cooling rates of up to 400 kK/s are analyzed in the study. © 2011 Pleiades Publishing, Ltd.

The crystallographic relationship between the structural components in high-carbon 120G4 steel after a partial isothermal pearlitic transformation has been studied by TEM. It has been found that a high density of microtwins and stacking faults was observed in the retained austenite. A new type of crystallographic relationship has been detected—parallelism of close-packed directions and planes of the structural components of fine-plate pearlite to one of the variants of twinned austenite.

Data are given concerning the structure and the chemical composition of carbon steel used for making cold arms, which was produced at the Zlatoust arms factory in the nineteenth and early twentieth centuries. The results of the analysis of the structure of metal demonstrates the general trend of the development of metallurgy both at the Ural plants and in the world: from the creation of the crucible methods of production of cast steel to the mass production of cast steel by the Bessemer and Martin methods.

The structural evolution of hypereutectoid U10 steel with a pearlitic structure of various types (fine lamellar or partly spheroidized pearlite) is studied during fatigue loading. The fracture of these structures is considered using fractography data. The specific features of the structural transformations and the changes in the dislocation structure of the U10 steel are revealed during cyclic tension in the high-cycle fatigue region at a significant distance (10 mm) from a fatigue fracture surface. Substantial structural changes are shown to occur in U10 steel with various pearlitic structures during high-cycle fatigue tests (tension at a stress amplitude in a cycle lower than the macroscopic yield strength). These are the fragmentation, partial dissolution, and spheroidization of cementite lamellae and the polygonization of the ferrite component. The relationship between the type of fracture surface and the type of structure formed upon fatigue loading is found.

Effect of the structure and texture formed upon thermomechanical treatment (TMechT) on the cold resistance of low-carbon low-alloy welding steel is considered. The structure has been investigated by the metallographic and electron-microscopic methods; the texture has been studied by X-ray diffraction method with the aid of the analysis of the orientation distribution function (ODF). Structural factors that affect an increase in the cold resistance, including creation of a submicrocrystalline structure, have been considered. It has been established that the components of the texture result from a regular crystallographic rearrangement of the texture of hot deformation of austenite into the texture of the α phase upon the γ → α transformation. It is shown that the dependence of the cold resistance of the rolled sheet on the fraction of the cube component in the texture of the α phase has a complex nonmonotonic nature.