ISSN (print): 2075-1133, ISSN (online): 2075-115X Главный редактор: Konstantin A. Solntsev Издатель: Pleiades Publishing Входит в: Белый список (уровень 3), Scopus, Web of Science (ESCI)
Scientific and Technological Bases for Developing Cold-Resistant Steel with a Guaranteed Yield Strength of 315–750 MPa for Arctic Conditions. Part 1: Alloying Principles and Requirements for Sheet Product Structure
Abstract—The results obtained upon choosing rational alloying and microalloying for cold-resistant steels with a guaranteed yield strength of 315–750 MPa on the basis of established interrelations between phase transformations, structure, mechanical properties, serviceability parameters, and the content of main alloying elements are presented. Quantitative requirements for various structural parameters and their maximum permissible difference throughout sheet product thickness up to 100 mm have been developed, depending on the strength category and manufacturing technology (thermomechanical treatment with accelerated cooling, quenching from separate furnace heating or rolling heating with high temperature tempering) to provide guaranteed characteristics of strength, cold resistance (impact energy KV at a testing temperature from –60 to –80°С, critical ductile-to-brittle transition temperature Тkb, and nil ductility temperature NDT), and crack resistance according to the criterion of critical crack tip opening displacement (CTOD).
Scientific and Technological Bases for Developing Cold-Resistant Steel with a Guaranteed Yield Strength of 315–750 MPa for Arctic Conditions: Part 2. Manufacturing Technology, Structure, Properties, and Serviceability of Sheet Products
Abstract—The paper presents results of the industrial implementation of hot plastic deformation and thermal treatment schemes for the production of rolled sheet products based on cold-resistant steel with yield strength not lower that 315–750 MPa for the Arctic. On the basis of the studies performed, a set of scientific and technological techniques has been developed for various technological processes (thermomechanical treatment followed by accelerated cooling, quenching from the rolling heating, and separate furnace heating with high-temperature tempering). The developed complex method provides the formation of a structure having an acceptable heterogeneity and anisotropy level corresponding to different morphological and crystallographic parameters throughout the entire thickness of rolled products up to 100 mm based on low-alloy steels with a yield strength not lower than 315–460 MPa and up to 60 mm based on economically alloyed steels with a yield strength not lower than 500–750 MPa. The structure of sheet products is presented that provides guaranteed characteristics of strength, cold resistance (impact energy KV at a testing temperature ranging from –60 to –80°C, critical ductile-to-brittle transition temperature Tkb, and nil ductility temperature NDT), and crack resistance according to a CTOD criterion in a low-temperature range to meet the requirements of the RMRS “Rules for the Classification and Construction of Ships” for steel with the Arc40 index.
Research of Recrystallization Processes in Low-Carbon Low-Alloy Steel in Modeling High-Temperature Rolling
Abstract—The processes of dynamic and static recrystallization occurring under various types of plastic deformation (compression pattern, deformation temperature) of low-carbon low-alloy steel are studied. Modeling of thermomechanical processing followed by a comprehensive analysis of the microstructure was performed on a Gleeble 3800. The studies performed revealed the thermal deformation conditions for the formation of a finely dispersed homogeneous steel structure. The results of industrial testing of the developed modes of hot rolling of sheet metal are given.
The Effect of Microalloying on Mechanical Properties of Low-Carbon Chromium–Nickel–Molybdenum Steel
Abstract—The work covers the effect of niobium, as well as both niobium and vanadium, on mechanical properties of high-strength chromium-nickel-molybdenum steel after thermal refining. The mechanical properties of steels were determined after applying various tempering temperatures (from 580 to 660°C) and durations of tempering (from 1 to 16 h), and also after quenching from rolling heat and furnace heat with subsequent tempering. It is shown that, after quenching and tempering in the temperature range of 580–660°C of the high-strength steel of the Cr–Ni–Cu–Mo composition alloyed with 0.02% Nb and 0.07% V, the yield strength is higher as compared with steel alloyed with niobium (0.05%), at only an insignificant decrease in the impact strength and ductility. Increase of the total composition of the basic alloying elements does not result in a significant change in the mechanical properties within the investigated tempering temperature interval. Quenching from rolling heat increases the strength while maintaining high toughness, and the increase in strength is most noticeable for steel microalloyed only with niobium.
Structure and Properties of the Intermetallic Alloy Based on Nickel Aluminide Microalloyed with Rare Earth Metals
Abstract—The combined influence of rare earth metals (praseodymium, neodymium, and erbium), the technology of smelting an intermetallic alloy based on nickel aluminide on pure charge materials using 25, 50, and 75 wt % of waste, and the technology of casting single-crystal billets and their heat treatment, combined with hot isostatic pressing, on mechanical properties and long-term strength at the level of certified data are investigated.
Basic Physicochemical Concepts for Controlling the δ-Ferrite Content When Welding with Austenite-Ferrite Materials
Abstract—By the example of the metal of a seam obtained using welding materials based on 10Kh19N11M4F steel which are currently used for the welding of high-strength low-alloy steels, the influence of its chemical composition on the behavior of δ-ferrite throughout the entire temperature range of its existence is shown. On the basis of these studies, the prospects of the use of 10Kh19N11M4F steel for the welding of high-nitrogen corrosion-resistant steels with the retention of their nonmagnetization, including in the area of the welded joint, are shown. The critical parameters determining the behavior of δ-ferrite upon crystallization and subsequent cooling of solid steel are found using thermodynamic modeling. It is shown that the depth of the σ-ferritic transformation and the maximum equilibrium temperature of austenitization used for the interpretation of the experimental data obtained during hot physical modeling of welding are the most important among them. The areas of promising compositions of the metal of the seam in the case of welding of low-alloy high-strength and high-nitrogen corrosion-resistant steels without hot cracks and providing, if necessary, nonmagnetization of the seam are found and depicted on the fragment of the improved Scheffler–Speidel diagram.
Modeling of Steel Hardening Process at Thermal and Mechanical Treatment
Abstract—The article deals with the modeling of thermomechanical processing of high-strength steels on the Gleeble 3800 research complex, simulating thermomechanical processing with various temperature and deformation parameters of rolling and with accelerated cooling to a predetermined temperature. The identity of steel hardening processes at the Gleeble 3800 complex and specialized rolling mills and also the possibility of obtaining steels of unified chemical composition are shown.
Synthesis and Electron Beam Facing of Titanium Monoboride–Titanium Matrix Composite Powders
Titanium monoboride–titanium composite powders with the titanium matrix content from 20 to 60% are obtained by self-propagating high temperature synthesis (SHS) in titanium and boron powder mixtures. The SHS powders are used for cladding of coatings with a thickness of up to 3 mm on a VT1-0 titanium sheet by electron beam facing. The phase composition and microstructure of the initial powders and cladded coatings are investigated via X-ray diffraction analysis and optical and scanning electron microscopy. On the basis of the microstructure investigation and microhardness profiles in the coating/base plate transition zone, a conclusion about effective adhesion of the coating to the base plate is made. The dependence of the hardness and abrasive wear resistance of the cladded coatings on the phase composition of the powders used for cladding is studied. It is found that the hardness of the coatings strengthened by needle-like titanium monoboride inclusions in the titanium matrix is 2.2-fold higher and abrasive wear is 3.7-fold higher when compared to the properties of VT1-0 titanium. Here, the effect of strengthening and increase in the wear resistance of the titanium matrix by titanium monoboride particles is much smaller than similar effects in the case of the use of disperse titanium carbide particles as the strengthening phase in cladded coatings.
Correlation of the Diamond/Matrix Interphase Zone Structure with Tool Efficiency Obtained by Technology Combining Metallization of Diamonds with Matrix Sintering
The paper studies the structure and phase characteristics of the interphase zone diamond/matrix in dressers made by thermal diffusion metallization of a diamond combined with matrix sintering based on WC–Co and Cu impregnation. The compact arrangement of chromium powder particles around diamond grains and the shielding effect of copper foil create favorable conditions for thermal diffusion metallization of diamond at matrix sintering. A metallized coating chemically bonded to diamond and consisting of chromium carbide and solid solution of cobalt in chromium phases provides a strong diamond retention in the carbide matrix. It is shown that it is formed on the surface of the diamond under the conditions specified in the experiment and the temperature–time sintering mode. The specific productivity of experimental dresser made by hybrid technology at straightening the green silicon carbide grinding wheel equaled 51.50 cm3/mg, exceeding that of the control dresser made without metallization of diamonds by sintering with copper impregnation by 44.66%.
Experimental Production of Cu–Cr–N Composite Alloys and Thermodynamic Modeling of Their Phase Composition
Composite Cu–Cr–N alloys were obtained in situ under vibration of “copper melt–chromium powder” compositions before their crystallization. Two types of alloys were prepared, where chromium powder was freely dispersed or compacted into a tablet. Atmospheric nitrogen was used as a source of chromium nitrides in the alloys. The microstructure of the alloys is represented by a copper matrix hardened with chromium particles and numerous inclusions of nonstoichiometric chromium nitrides Cr2N1 – x. Thermodynamic modeling showed that the composition and quantities of chromium nitrides in the Cu–Cr–N alloy depend on the partial pressure of nitrogen above the melt.
The Influence of Technological Parameters of Cold Gas Dynamic Spraying on Wear Resistance of Aluminum–Carbon Nanofibers Coatings
The microhardness, coefficient of friction, elastic modulus, elastic recovery coefficients, and plastic deformation resistance are determined for functional aluminum matrix–carbon nanofibers coatings. Wear rate tests were carried out to evaluate the wear resistance of functional coatings, as well as to predict their service life. The coatings with the best mechanical and wear resistance characteristics were distinguished as well.
Catalytically Active Coatings for Systems of Steam Conversion of Natural Gas: Synthesis and Catalytic Properties
Scientific and engineering problems in development of catalytically active compositions for immobilized catalyst systems for steam conversion of hydrocarbon feedstock to hydrogen fuel have been considered. Processes for synthesis of catalytic powder mixtures and production of functional coatings based on them with the use of a promising method of supersonic cold gas-dynamic sputtering have been studied. The data of experimental study in the field of development of catalysts for methane steam conversion to hydrogen-containing fuel on the Cr15Al15 tape support using as starting materials Ni–Al–Al(OH)3–Ca(OH)2–Mg(OH)2 composite powder mixtures are given.
Obtaining Functional Intermetallic Ni–Ti Coatings by Heterophase Transfer Combined with Laser Treatment
The results of the investigation of the intermetallic Ni–Ti system coating obtained by the complex method of cold gas dynamic spraying and laser treatment are presented. The dependence of the coating charge composition on the initial powder composition is shown. Its structure, porosity, and microhardness are studied, and also the results of X-ray phase analysis confirming the presence of the intermetallic phase are presented. The microhardness is increased by more than a factor of 5 to 632 HV, and the porosity is decreased by a factor of 25 to 0.2%. Investigation of the substrate–coating boundary shows the presence of mutual diffusion.
Modern Approaches to the Development of Marine Antifouling Coatings
At present, 75–80% of the current operating costs of conventional transport are expended for fuel. According to the International Maritime Organization, the world fleet burns 300 million tons of fuel annually, releasing into the atmosphere 960 million tons of СО2 and 9 million tons of SO2. As a result of fouling, the speed of ships may decrease by 50%. By 2020, without new technologies that reduce fuel consumption, air emissions can grow 40%, taking into account constantly increasing volumes of traffic. Therefore, defense methods against marine overgrowth are an urgent topic, and many leading firms are developing antifouling solutions. The paper considers the main means of protection against fouling with the help of polymer coatings, namely, contact active coatings, nonleaching coatings, self-polishing coatings, and non-biocidal coatings. The mechanism of using polymer coatings, as well as their advantages and disadvantages, is described.
Strength Improvement of Metals Produced by Selective Laser Melting of Powders
Standard samples for mechanical tests have been produced by selective laser melting (SLM) of metal powders of various chemical compositions. It has been determined that strength properties of all SLM samples are higher than those of solid samples of the same chemical composition. It has been established that the factors of strength improvement are vapor condensed nanoparticles above the melting zone and ultrafine grain structure formed at the stage of crystallization.
Biotechnological Method of Obtaining Nanoparticles of Silver, Cadmium, and Zinc Sulfides. Physico-chemical Characteristics. Creation of Polymeric Nanocomposites
A simple and environmentally safe method for obtaining stable nanoparticles of metal sulfides nanoparticles—NpAg2S, NpCdS, and NpZnS—was developed using different strains of microorganisms in an aqueous solution of metal salts and sulfur sources at the National Research Center Kurchatov Institute—GosNIIgenetika. The concentration of nanoparticles is 1‒4 mg/mL in aqueous suspensions. Using the methods of electron microscopy, spectrofluorimetry, and dynamic light scattering, the main characteristics of biogenic nanoparticles were determined: shape, size distribution, crystal structure, effective diameter, luminescent spectrum, and zeta potential. According to their characteristics, these nanoparticles are referred to quantum dots. It is established that the stability of nanoparticles in aqueous suspensions is due to protein molecules adsorbed on the surface of nanoparticles, which are supplied by cells of microorganisms. Effective immobilization of biogenic nanoparticles on the surface of various polymer supports was carried out. Biogenic nanoparticles along with nanoparticles obtained by physico-chemical methods can be used as fluorophores for imaging of biological processes, also as photocatalysts, solar cells, and for new nanocomposite materials.
Epoxy Radiotechnical Hot Pressed Glass Fiber Plastics for Ship Aerial Fairings and Protection of Antennas in Radio Connection and Radio Location Systems
The present work is aimed at solving an urgent scientific problem of creation of high-strength and water-resistant dielectric glass-reinforced hot pressed glasses using bi- and polyfunctional epoxy amine binders and fiberglasses from alkalineless, quartz, and silica glasses, as well as their use in shipbuilding.
Heat-Resistant Antifriction Carbon Plastics for Sliding Bearings of Pumps of Ship Power Stations, Thermal and Nuclear Power Plants
The paper summarizes the experience of development and application of high-speed sliding bearings for centrifugal pumps of ship energy units, thermal electric stations, and nuclear power plants. The operation of sliding bearings involves superheated water to temperatures of 200°С and at sliding velocities of 20–40 m/s. Unlike metals, these sliding bearings need no additional oil lubrication. Two antifriction carbon plastics, namely, phenolic type FUT-B and new polyphenylene sulfide type UPFS, are discussed.
On the Microstructure and Chemical Composition of the Polyimide Film Surface and Condensed Substances after Long-Term Exposure at the Mir Space Station
Using scanning electron microscopy, electron probe microanalysis, and infrared spectroscopy, we comprehensively studied changes in the microstructure and chemical composition of the surface layers of the PM-1E polyimide film, as well as the substances condensed on it, which for a long time (1218 days) was exposed at the Mir orbital space station. It was shown that, during the exposure in space, the microstructure and chemical composition of the film changes only in the first layer of the packet and that no such transformations are observed in the layers located below. On the open surface of the first layer of the polyimide film, new phase formations of various shapes and sizes with both film and needle-like structures differing in chemical composition were discovered. It was found that the condensed matter formed consists of compounds involving silicon, iron, copper, zinc, chlorine, potassium, and calcium, which are likely to precipitate from the own external atmosphere of the orbital station.
Factors Influencing the Fire-Resistance of Epoxy Compositions Modified with Epoxy-Containing Phosphazenes
The flame resistance of epoxy compositions based on resin D.E.R.-330, isomethyltetrahydrophthalic anhydride, and new epoxy-containing aryloxycyclotriphosphazenes according to GOST (State Standard) 28157-89 (analog of the test UL-94) was studied. Thermogravimetric analysis and microstructural investigations of the coke residue formed during combustion were performed. It was found that an increase in the phosphazene content of cured compositions increases significantly their flame resistance, and this is connected with both increase in the amount of porous coke residue, which is the barrier against flame propagation and flame heat transfer onto the sample, and increase in size of pores arising in coke residue. The data obtained can be used to create tough and flame-resistant composite materials for microelectronics, the aircraft and other industries.
Organoplastic for Composite Hull Constructions Exploited in Marine Environment
The results of the development of a three-layer polymer composite material for hull structures operating in a marine environment with an organic plastic middle layer are considered. The physicomechanical properties of the organoplastic are studied to justify the choice of starting materials, the structure, and the technology for its manufacture.
Main Directions for Research on the Development of Tribotechnical Composites Used in the Arctic Regions (Experience of North-Eastern Federal University in Yakutsk)
Materials science studies the relationship between the structure and properties of materials and their changes under external impacts, and it belongs to the priority domains of science and technology. The creation of new materials, improvement of existing materials, and development of efficient technologies for their processing are the main goals of materials science. Today a substantial number of new metal alloys with special properties, different composites, ceramics, polymers, nanostructured functional powder and synthetic superhard materials, multifunctional coatings, etc., have been designed for various economic activities. But the creation of materials and technologies remains an urgent need because of the progressive development of manufacturing which requires adaptive properties of materials and technologies for their processing. This review analyzes the directions of research at North-Eastern Federal University in the field of tribotechnical materials for use in the Arctic regions. The main areas of research are identified, namely, development of new technologies of production of polymer composite materials (PCM) and improving their performance properties. The prospects of physical processing and chemical modification of the polymer matrix surface are shown. Physicomechanical and tribotechnical properties of antifrictional PCM are discussed. The results of the main theoretical generalizations in the field of analysis of PСM supramolecular structures are presented: (1) effects of critical filler concentrations on the structure and properties of PCM; (2) hypothesis of the nature of intermolecular interaction between the filler and the polymer. The modern trends of scientific investigation are shown, one of which is tribooxidative processes in PCM. The specific development of scientific knowledge and the use of polymers for the northern regions are revealed.
Mechanical Properties of the Welded Joints of the Pressed Aluminum–Magnesium 1565ch Alloy at Low and High Temperatures
The paper shows the research results of the structure and mechanical properties of welded joints of the hot-pressed panels and profiles manufactured by JSC Arkonik SMP from aluminum–magnesium 1565ch alloy at the temperature range from –165 to 150°C. It is established that the nature of changes in the properties of welded joints of pressed panels and profiles of 1565ch alloy made by manual argon arc welding with non-consumable electrodes of TIG with filler material СвАМг61 at various test temperatures is similar to changes in the welded joints of rolled sheets. When the test temperature is lowered, low-temperature hardening of the welded joints is observed—at cryogenic temperature (–165°C), 20–30% of strength is gained compared to 20°C. The prolonged aging of welded joints at an elevated temperature (150°C) leads to a decrease in strength by 25–30% compared to 20°C. The strength coefficient of welded joints with reinforced joint is not less than 0.9 of the actual strength of the base metal at all test temperatures.
Managing Welded Joint Formation at Electron-Beam Welding of Aluminum Alloys of Increased Thicknesses
Abstract—The technology of electron beam welding of homogeneous and dissimilar welds of aluminum alloys 1561, 1560М, and 1980T1 has been developed. Beam scanning along the semielliptical trajectory has secured the quality of the welded parts with fine mechanical properties. The welding scheme and optimal modes have been determined. The results of mechanical and corrosion tests, as well as the results of the delayed failure tests, are presented. The technology is implemented for hydrofoil devices and for the manufacture of shipbuilding machinery components.
Degradation of Fuel Cladding Materials Based on Zirconium after Operation in VVER-Type Reactors
The paper presents microstructural studies of specimens cut from fuel elements made of E110 spongy zirconium-based alloy after operation in a VVER-1000 before reaching the burnup of ~35 MWd/kg U. As a result of exposure to high temperatures and neutron irradiation, significant changes in the phase composition of fuel cladding materials appear: change in the size, density, and composition of β-Nb particles; change in the composition of the Laves phase; formation of dislocation loops of α type, as well as δ and γ hydrides. The main structural elements determining the degradation of the mechanical properties of the E110 alloy under irradiation are dislocation loops and fine-phase precipitates owing to their relatively large density. The data obtained can be used to construct dose dependences of microstructural changes with the aim of predicting the residual life of claddings and fuel assemblies as a whole.
Zirconium Alloys with Low Melting Points
A novel class of low-melting Zr-based alloys has been developed. They are deep triple and quadruple eutectics with very low melting points from 690 to 860°C. Low-melting Zr-based alloys have been proposed as a matrix material for fuel elements with dispersed high-U fuel. Proposed fuel compositions have been developed with high thermal conductivity and U content (25–50% higher than in the case of VVER and PWR fuel rods). As applied to PWR and BWR reactors, they have some advantages compared to conventional uranium dioxide fuel pellets. The use of new dispersion fuel can improve neutronic characteristics of the reactors, increase burnup, reduce fuel temperature, and improve fuel efficiency.
The Basic Principles of Assessment of the Structural Integrity and Lifetime of the BN-Type Fast Neutron Reactor Components Considering Material Degradation
The paper presents an overview of the basic principles of extending the lifetime of BN-600 fast reactors. These principles based on analysis of the main in-service mechanisms of material embrittlement and damage underlie the normative documents of the Rosatom State Corporation and were used by the authors in their developments for justification of the design lifetime of the BN-800 and BN-1200 fast reactors. The so-called critical events and limit states that determine the structural integrity and lifetime of fast reactor components have been formulated. On the basis of the results of this work, the repost “Basic Principles for Lifetime and Structural Integrity Assessment of BN-600 and BN-800 Fast Reactor Components with Regard to Material Degradation” was made at the International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17) held by the IAEA in Yekaterinburg in 2017.
Quality Control of Steels for Large-Sized Welded Structures of the Arctic Shelf: Application of Russian and Foreign Requirements
Abstract—The implementation of large-scale projects for the development of the Arctic inevitably requires the participation of both Russian and foreign manufacturers of marine facilities and, accordingly, the use of both domestic and foreign steels. In this regard, it is advisable to compare the order of appointment of Russian and foreign regulatory requirements for steels designed for operation at low climatic temperatures and for the welded joint metal and to analyze the theoretical and experimental validity of these requirements. This is especially important owing to the fact that differences in metal quality requirements can serve as a tool to drive out Russian steel manufacturers from international projects.
A Mathematical Model of Radiation-Induced Shape Change in Fuel Subassemblies of the BN-Type Reactor Core and Its Implementation in the ANSYS Software Package
One of the main operability criteria for fuel subassemblies (FSAs) in sodium-cooled fast reactor cores, i.e., the criterion of tolerable shape change in the hexagonal wrapper tube, is formulated. The equations that enable one to investigate the kinetics of the stress-strain state of a three-dimensional body have been adapted to operating conditions of the FSAs. A mathematical model of radiation-induced shape change in ferritic-martensitic EP-450 grade steel is proposed. With regard to the proposed model and data on the radiation-induced shape change in other currently used and prospective BN reactor core structural materials, blocks for recording radiation-induced swelling and radiation-induced creep were developed for the ANSYS software package, which made it possible to utilize its potential in this area. The test case with the proposed models of the radiation-induced swelling and creep demonstrates that the developed blocks describe sufficiently well the radiation-induced shape change in the examined structural materials exposed to radiation. Calculation of the radiation-induced shape change in the FSA hexagonal wrapper tube has been performed at various radiation-induced swelling rates and radiation-induced creep moduli. The calculated results and the results of post-irradiation inspection of the FSA dimensions are compared. Recommendations for use of the proposed models designed to calculate and estimate the radiation-induced shape change and define the stress-strain state of the FSAs are made.
X-ray Nondestructive Testing as an Essential Tool during Technology Design and Development of Modern Aircraft Materials
The X-ray nondestructive testing process is carried out by a system which includes an object of control (OC), source of radiation, detector, and operator. Under interaction of radiation with the OC, its radiation image is formed as an X-ray dose distribution in accordance with the OC properties. At this stage, useful information about the OC is formed, which is further partially lost, partially distorted, and veiled with a noise by conversion of a radiation image into an optical one. The optical image is analyzed by an operator, and the result of testing depends on his physical and emotional state. In this article, the step-by-step analysis of the entire radiation monitoring system is performed. The first stage is formation of a radiation image. For the theoretical estimate of the minimum defect size detected by the X-ray testing system, spatial-frequency spectrum analysis was used. The minimum sizes of a defect were established, for which the radiation image will be formed depending on the characteristics of the source of radiation and the OC. The second stage is the transformation of the radiation image into an optical one. We presented the simulation of this process and developed a model of how an operator recognizes the X-ray optical image and makes the decision about the OC condition. The optical image formation was studied and the choice criterion for the radiation energy was determined by using the digital radiography technique.