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To improve erosion resistance, strength, and other protective properties, a comprehensive modification of the surface layers of 25CrMoV steel, which is widely used in turbine construction, was performed. For comparative studies, modifications with different interlayer materials (Mo and Ti) and modifications without interlayer were used. The Mo and Ti layers were deposited on a nitrided ion plasma surface. The outer protective layer for all modifications was unchanged and consisted of a Mo2N coating. To determine the role of the deposition of interlayer metal coatings on the strength properties of the complex modified coatings, the distributions of hardness (H, GPa), Young's modulus (E, GPa), and other strength parameters (H/E and H3/E2) measured by cross sections (h, μm) were investigated. The hardness of the Mo2N coating was ~30 GPa, and the hardness of the nitrided layer was ~12 GPa. The modulus of elasticity for the Mo2N coating was ⁓415 GPa, and for the nitrided steel - ⁓270 GPa. It was found that the main factor influencing the strength properties of a multilayer structure is related to the different materials of the metal layers. For the Mo and Ti layers, the values of E differ significantly (⁓ 340 GPa and ⁓ 180 GPa, respectively), with almost identical values of H (⁓ 6.5 GPa). The distributions of elastic modulus E = f(h) measured in the modified layers correlate well with the distributions of nitrogen concentration CN = f(h). The distributions of H/E = f(h) and H3/E2 = f(h) for the modifications with Mo and Ti layers show a decrease in mechanical properties in the areas of the intermediate layers (Mo and Ti). For the modification without interlayer, the distributions of these indicators do not show such a drawback. The cavitation resistance of the comprehensively modified 25CrMoV steel is up to 2 times higher than that of the steel in the original condition. NSC KIPT performed extensive ion plasma modification on a pilot batch of turbine parts. These products, which are part of the steam distribution mechanisms, were manufactured by Ukrainian Power Machines JSC (Kharkiv) for the thermal power industry. [ABSTRACT FROM AUTHOR]

Introduction/purpose: It has been known for a very long time that timedependent effects such as creep and shrinkage of concrete considerably influence the behavior of composite steel-concrete beams. It is therefore very important to take these effects into account when calculating the strength and safety of composite steel-concrete beams. To this end, many theoretical and numerical research studies have been established to control this phenomenon. Most of this research presents laborious processes and calculations requiring complex techniques. Methods: This model consists of combining the static equilibrium equations and the two compatibility relations, in curvature and in deformation, of the composite steel-concrete cross-section with the differential equation resulting from the creep rate theory (RCM). The idea of this work was to take this model and simplify it to avoid difficult mathematical transformations. Results: The results from this simplified approach are very satisfactory when compared to those given by the analytical model. Conclusion: To overcome an excessive number of calculations and various difficulties associated with analytical or numerical methods to estimate additional stresses brought by the shrinkage of concrete in composite steelconcrete beams, a simplified analytical methodology has been proposed here while ensuring desired safety. This work has tried to simplify an existing analytical model based on the theory of linear viscoelasticity established in 2012. [ABSTRACT FROM AUTHOR]

The aim of the work is the first stage in the development of a new ampoule backup chemical current source based on the lead dioxide reduction reaction, namely the selection of the cathode base material. The main objects of the study were cathodes made of titanium, steel, and lead with a galvanic coating of lead dioxide formed from a nitrate electrolyte using current density 1...2 A/dm2. To obtain a titanium cathode, the problem of surface passivation was solved using an initial symmetric cathode polarization for 30 seconds. To establish the dependence of the specific characteristics of the system on the material of the base, discharge curves were obtained and the dynamics of the discharge of different cathodes were established. The discharge curves were taken at a constant resistance of 7.3 Ω using a system with zinc anodes and perchloric acid as an electrolyte. The maximum stable discharge potential of the current source was found in titanium cathodes (1.8 V for 23 seconds). Moreover, when obtaining the polarization curves, the tendency of the steel cathode to peel off the coating and corrosion in the electrolyte was revealed, while the titanium cathode demonstrated stable current rates from cycle to cycle. Researching of the lead cathode showed low adhesion and/or conductivity between the formed powder coating and the base material. The study revealed that the optimal material for the base of the lead dioxide cathode for the backup current source, both from the point of view of chemical stability and discharge characteristics, was titanium. Therefore, it will be used in further studies of other components of the electrochemical system. [ABSTRACT FROM AUTHOR]

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В статье рассматривается влияние комплексной химико-термической обработки (КХТО) стальных изделий, включающей в себя цементацию, диффузионное насыщение хромом и закалку на коррозионную стойкость стальных изделий в 30% водном растворе HCl и 3% NaCl. В качестве обрабатываемых материалов использовались стали Ст3, 40Х, 40Х13, 20Х13. Было выявлено, что КХТО позволяет получать покрытия толщиной от 7 до 27 мкм, при этом микротведрость поверхности покрытых образцов достигает 24000 МПа в зависимости от температуры КХТО. Было выявлено, что на скорость коррозии влияет элементный состав покрываемого материала, режимы КХТО, состав коррозионно-активной среды. Проведение испытаний образцов выявило, что стали без покрытий имеют более низкую коррозионную стойкость, чем материалы, подвергнутые КХТО. При этом, скорость коррозии материалов снижается пропорционально увеличению содержания хрома в и снижению содержания углерода в покрываемом материале. Наиболее эффективно скорость коррозии снижается в среде NaCl. Так, скорость коррозии образцов, изготовленных из стали Ст3, снизилась в 11,6 раз, из стали 40Х в 8,22 раза, 40Х13 в 4,56 раза, 20Х13 в 4,1 раз. В 30% водном растворе HCl скорость коррозии образцов, изготовленных из стали Ст3, снизилась в 4,6 раз, из стали 40Х в 4,4 раза, 40Х13 в 3,99 раз, 20Х13 в 3,84 раза. Также, было выявлено, что на коррозионную стойкость оказывает влияние температура КХТО. Так, при температуре КХТО 1000°С скорость коррозии в 3 % NaCl составляла 0,08 г/(м2*час). При увеличении температуры до 1070°С скорость коррозии уменьшалась до 0,059 г/(м2*час). Аналогично температура КХТО влияла и на другие исследуемые материалы.

Introduction. For steel armor materials, it is important to reduce the thickness and, consequently, the metal consumption of the protective structure. The previously developed class of materials with the structure of a natural ferrite-martensite composite (NFMC) has characteristics that favor the inhibition of crack development under impact loads and has prospects as an armor material.Problem Statement. The purpose of this work is to evaluate the possibility of using NFMC materials for armor protection devices based on the results of ballistic resistance tests under a high-power concentrated impact (a projectile flying at a hyper-high speed).Theoretical Part. The study of ballistic resistance was carried out on samples of steel 14G2 processed according to various modes. The samples had the shape of plates and a square grid on the surface. Simulation tests of the impact of heat-strengthened dowels from a powder-actuated tool and firing of military small arms at the testing site from an SVD sniper rifle and an AK-74 assault rifle with machine loading ammunition were carried out. The results of simulation tests showed a clear advantage of steel with the NFMC structure. The comparison of the results of firing with military small arms has showed that the ballistic resistance of steel with the NFMC structure depends on the ratio of the volume fractions of ferrite and martensite, which cause different thicknesses of the ductile and strong components of the composite. The highest resistance was observed for a sample with an NFMC structure processed according to the regime: quenching 730°C and tempering 180°C.Conclusions. Steels treated for the NFMC structure can provide effective protection for military personnel with a lower material consumption of armor protection devices, which is due to a special method of braking destruction during a high-power local impact. Thus, the practical application of the developed class of natural composite materials seems promising for obtaining an armor plate with a thinner thickness, which helps to reduce the weight of combat vehicles, increase their mobility and reduce fuel consumption.

The method is proposed to protect the carbon steel from corrosion by silicate coatings filled with powdered zinc and graphene nanoplates obtained by thermal splitting of graphite. The conditions for steel pre-treatment in an alkaline solution containing citrate ions and a nonionic surfactant, for the production of potassium liquid glass composition with the addition of zinc and graphene powders are selected. It is shown that coatings 70–80 µm thick, cured at room temperature for three days and containing 80–90 wt. % zinc, 7– 12 wt. % silicon dioxide and 0.2 wt. % carbon have the highest adhesion, water resistance and protective ability. The study of steel corrosion in 3.5% NaCl solution using methods of voltammetry and the dependence of open circuit potential on the test duration showed that silicate coatings filled with zinc and graphene provide cathodic polarization of steel and protect it from corrosion better than twice as thick coatings obtained by hot galvanizing. Graphene nanoplates enhance the contact of zinc particles with each other and with steel, promoting its cathodic polarization. Using scanning electron microscopy and X-ray spectral microanalysis, it has been shown that zinc corrosion products fill the pores of the near-surface layer of coatings, enhancing their protective ability. [ABSTRACT FROM AUTHOR]

Purpose is to analyze steel degradation of the internal well equipment during its continuous service while contacting directly the corrosive environments. Methods. A range of research concerning the damaged metal tubes of the internal equipment for oil and gas wells, in particular regarding continuous service tubing, comprised both standard and specific studies involving different variations of X-ray spectral analysis with the use of scanning electron microscope JSM-35CF (JEOL Company, Japan) and SEM-515 with microanalyzer Link by Philips Company. The studied samples have been made of tubing in the period of the unauthorized and emergency well shutdowns; life of the wells is 0 up to 15 years. To analyze both structure and chemical composition of metal inclusive of such gases as oxygen and hydrogen, chippings were produced mechanically from various parts of tube walls. Findings. X-ray structural studies have made it possible to obtain data confirming cementite decay (Fe3С) in the tube metal during continuous operation of the internal well equipment. X-ray structural analysis methods have helped identify the parameters of crystal lattice of a matrix; and a level of elastic distortions of the lattice (i.e. microstresses of the distortions) has been evaluated as well as carbon distribution within ferrite and cementite. The abovementioned offered the possibility to describe both reason and mechanism of the reduced resistance to corrosion in the context of internal well equipment. Originality. New regularities under cementite decay in tube metal have been identified in addition to changes in the parameters of a crystal a lattice; microstresses of the lattice distortions; and carbon distribution within ferrite and cementite. The aforesaid helps explain in a new way both reason and mechanism of the reduced resistance to corrosion in the context of internal well structures operating continuously in aggressive environments. The basic sources and mechanisms of tube steel degradation, resulting from the metal hydrogenation and oxidation, have been defined which becomes the foundation to develop scientifically the substantiated measures mitigating the negative impact on the condition of the internal well facilities operating continuously in the chemically aggressive environments. Practical implications. Degrading hydrogen effect on the crystal lattice of metal has been proved. The effect creates conditions under which tube structures of oil and gas wells experience their failure. [ABSTRACT FROM AUTHOR]

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The technological features of producing brass-steel joint by the method of autovacuum heating are considered. The thickness of the brass layer after mechanical treatment was 10 mm. Studying the structures and chemical composition of various joint zones confi rmed the solution-diff usion nature of interaction of liquid brass with steel. The measurements of microhardness showed the absence of hard and brittle structures. A high quality of the joint was confi rmed by mechanical tests of the two-layer joint on static bending, rupture and shear. 17 Ref., 2 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

Copyright of Eurasian Physical Technical Journal is the property of E.A. Buketov Karaganda University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. is to perform analysis of corrosion durability (fatigue) of pump rod materials in terms of various chemically active simulation environments, and study influence of economically modified rare-earth impurity on corrosion fatigue strength of pump rod materials. Methods. 40 and 20N2M steel grades have been applied as well as experimental steel (ES). Steel of the conditinal ES grade has been melted within a pilot site of Institute of Electric Welding Named after E.O. Paton of the National Academy of Sciences of Ukraine. The steel was alloyed economically by means of a micro impurity of a rare-earth element (REE) being 0.03% of cerium; in addition, it contained comparatively low concentration of sulfur and phosphorus as well as minor concentration of dissolved hydrogen. The following has been used as simulation environments: 1) NACE environment (i.e. 5% NaCl solution which contained 0.5% CH3COOH, and saturated H2S; t = 22 ± 2°C; pH = 3.8-4.0); 2) 3% NaCl solution without hydrogen sulphide. Once every day, the environment was replaced to oxygenate it up to 8-10 mg/l concentration. Findings. Stability against sulfide stress-corrosion cracking (SSCC), hydrogen initiated cracking (HIC), and corrosion fatigue of steel of deep pump rods for oil industry has been studied. It has been defined that the experimental steel, modified economically by means of micro impurities of a REE, meets NACE MR0175-96 standard in terms of chemical composition as well as strength; in turn, 20N2M and 40 steel grades have high resistance neither to SSCC (threshold stresses are < 0.8 s) nor to corrosion fatigue attack; moreover, steel grade 40 has demonstrated low resistance to HIC (CLR > 6% and CTR > 3%). Originality. It has been identified that corrosion fatigue attack results from hydrogen penetration of steel initiating its cracking and hence destruction under the effect of alternating loads accelerated by the action of corrosive environment. Further, surface micro destructions, influenced by micro stresses, transform into large discontinuities and cracks with following macro destructions. Practical implications. It has been proved that high resistance to corrosion cracking can be achieved by means of refining of pump-rod steel of ferrite and perlite type using metallurgical methods, i.e. 0.01-0.03% REE microalloying. [ABSTRACT FROM AUTHOR]

Subject and purpose. Currently, gas, solid-state, and fiber lasers are used to process materials in the aviation industry. For the thermal treatment of steels, gas CO2 lasers with a capacity of more than 1 kW used, which are reliable in operation but have high cost and low efficiency. There are no results on the use of low-power (up to 20 W) pulsed-mode lasers for surface hardening of steel products. The purpose of this work is to determine the modes of surface hardening of products from carbon and alloy steels using low-power solid-state pulsed YAG lasers. Methodology. For laser hardening, a 5 W solid-state YAG laser was used (diode pumping, radiation wavelength λ = 1,064 μm, pulse mode). The use of a nonlinear crystal made it possible to obtain UV radiation with λ = 0,355 μm (third harmonic). The following modes were investigated: processing with single pulses (duration 0,1...0,4 ms) and multi-pulse processing with short (30...70 ms) pulses. The scanning speed was 8...2 mm/s. The energy in the pulse was determined by the photoelectric method. Thermal hardening was performed on the following steels: У12, P6M5. The possibility of UV radiation hardening was evaluated on steel 20, 45, У12, and ШХ15. Findings. The optimum values of pulse duration for maximum hardness in laser hardening of the investigated steels. With multi-pulse treatment of steels, the pulse duration is shorter than with single-pulse treatment, the hardening intensity is higher, and the quality of the processed surface is better. Single-pulse and multi-pulse processing are accompanied by partial melting of the surface of steel products, which does not allow it to be used in cases where a high quality of the surface is required. Laser hardening of steel by ultraviolet radiation is not accompanied by melting. Conclusion. For surface hardening of products, where partial melting of the surface is possible, low-power lasers in pulse mode can be used. Laser hardening by ultraviolet radiation is a promising direction for thermal hardening of steels, which allows maintaining the original quality of the surface layer. Thermal hardening with low-power lasers can be effective for small-sized areas of the processed parts of the fuel equipment of aircraft engines, friction elements, and, especially, the tool is small.

Magnetic pulse welding is an innovative joining method that allows combining dissimilar metals. The article discusses weldability of copper rings with steel rods in order to study the possibility of using single-turn inductor. All specimens were welded with a discharge energy of 18 kJ. Significant deformations of copper rings were observed. Metallographic examination of welds revealed no defects. High-quality joining of metals in the welding zone with a characteristic wavy boundary interface was noted. However, to obtain more information on the exact mechanisms of weld formation, it is recommended to carry out numerical modeling of the process. [ABSTRACT FROM AUTHOR]

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The stress state of a thin tungsten ribbon and magnetron-sputtered tungsten coatings on a ferrite steel substrate were investigated by X-ray tensometry (sin²ψ method). In-plane biaxial compressive stresses were revealed in the samples of the tungsten ribbon:  δy = −0.40 GPa and − 0.45 GPa in the rolling direction and δx = − 0.28 GPa and − 0.25 GPa in the direction perpendicular to the rolling direction from the front and back sides, respectively. The magnetron-sputtered tungsten coatings have in-plane equiaxial stresses, rotationally symmetric with respect to the surface normal ( δx = δy ). The stress magnitudes in the tungsten coatings are several times higher than those in the tungsten ribbon. The highest compressive stress (– 3.7 GPa) was found in a tungsten coating with a nominal thickness of 250 nm, in a coating with a thickness of 460 nm, the stress level was 1.5 times lower. The peculiarity of the analysis was that in the case of the tungsten ribbon, the line (310) was used, which certainly belongs to the precision region of the diffraction angles, while in the case of the tungsten coatings, due to the overlap of (310) α-W and (220) α-Fe lines, the lines (220) and (211) were used, which satisfy this condition to a lesser extent. The use of relatively soft Co-radiation (compared to Cu-radiation) somewhat mitigated this discrepancy. The stress-free lattice parameter (a0), corresponding to the undeformed cross section of the strain ellipsoid, was lower in the tungsten ribbon and higher in the coatings than the reference value for α -W; as the coating thickness increases, this difference increases. The reasons for these differences are discussed. Considering the broadening of the tungsten diffraction peaks, it was found that both the small size of the crystallites and the microstrain of the crystal lattice are the cause of this broadening in the samples of both groups, although the microstructure of the coatings is much more defective. [ABSTRACT FROM AUTHOR]

Most superalloy steels, especially those alloyed with chromium, tungsten, cobalt, and molybdenum, are strongly riveted during plastic deformation by drawing. Superalloy steels with a clean, scale-free surface are susceptible to stick-slip with the carbide tool - drag. Therefore, in case of cold deformation, it is necessary to use special lubricants with extreme pressure components and strong lubricating coatings. After cleaning the surface from scale, a lime-salt coating is applied. Recently, a fairly effective sub-coating of the composition (in an aqueous solution) has been used: sodium sulphate Na2SO4 - 130...250 g/l; liquid glass Na2SiO3 - 20...30 g/l; treatment at a temperature of 80...90°C. In some technological processes, thin metal coatings are used as an oil coating - copper, lead-tin, and oxalate. After deformation, all types of coatings must be completely removed, since heat treatment can lead to processes of interaction of metal with lubricating coatings. This can lead to deterioration of the surface quality and loss of the necessary properties. The purpose of the study is to create a methodological framework for the oxidation processes of superalloys of the working layer and interfacial surfaces of bimetallic pairs. Methodology - thermodynamic calculations of the equilibrium of chemical reactions on the metal - gas phase interface surfaces. The paper presents the results of experimental studies with the established dependence of the isobaric potential on temperature for reactions on the interfacial surface "Me2 - gas phase". The authors obtained the dependence of the isobaric potential on temperature for gaseous reaction products on the surface of superalloys. The existence of the dependence of the isobaric potential on temperature for reactions of the formation of complex oxides on the surface of superalloys is confirmed. Scientific significance - the adequacy of oxidation processes of superalloys of the working layer and interfacial surfaces of bimetallic pairs has been experimentally confirmed. [ABSTRACT FROM AUTHOR]

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Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Надано опис нової конструкції вібраційної машини для зміцнення поверхневим пластичним деформуванням циліндричних довгомірних деталей, зокрема стабілізаторів колісних візків залізничних вагонів. Окреслено основні конструктивні та технологічні параметри процесу вібраційно – відцентрового зміцнення цих деталей. На циліндричних зразках із сталі 45 експериментально досліджено вплив технологічних параметрів даного зміцнювального процесу на такий основний показник зміцнювальної обробки як глибина зміцнення. Наведено математичні залежності для вибору оптимальних значень конструктивних та технологічних параметрів даної зміцнювальної обробки. Окреслено перелік довгомірних циліндричних деталей, для яких придатна і ефективна вібраційно – відцентрова зміцнювальна обробка, серед яких торсіонні вали підвіски військових танків, осі коліс залізничного транспорту, бурові та обсадні труби газо- та нафтовидобувних свердловин.

Исследовано деформационное поведение в ходе растяжения клеевого соединения сталь/сталь. Выявлена временная эволюция изополей деформаций в приповерхностных слоях образцов соединений. Установлена корреляция между стадиями на деформационных кривых и картинами эволюции пространственных структурных элементов, которые на поверхности стальной накладки отражают пространственно-локализованное распределение деформационных полей. Эти деформационные поля ограничены изолиниями, внутри которых деформация имеет одинаковое значение. Выявлено, что на поверхности стальной накладки происходит расслоение на три типа областей: деформируемые области растяжения; деформируемые области сжатия; недеформи-руемые области. На стадии, предшествующей разрушению клеевого соединения, установлено предельное значение сдвигового смещения, которое равно 0,0067 мм. При этом показано, что на близких к периферии участках на площадях склеивания начинают расти напряжения в направлении, перпендикулярном площади склеивания. Эти напряжения способствуют возникновению отдирающих усилий. Установлено, что для исследуемого случая характер разрушения клеевого соединения является адгезионным.

Ионная бомбардировка поверхностей, модифицируемых с использованием вакуумно-дуговых технологий, является основным физическим процессом для таких модификаций. Эксперименты производились на установке типа «Булат». В работе по азотированию поверхностей массивных стальных деталей (ст. 25Х1МФ и 40Х) исследованы особенности использования в качестве бомбардирующих частиц ионов титана и молибдена, обладающих различным энергосодержанием. Этот этап ионной бомбардировки связан с очисткой поверхности и нагревом её до необходимой температуры. На этапе азотирования бомбардировку осуществляли ионами азота, генерированными в двухступенчатом разряде. Для диагностики изменений, происходящих на поверхности образцов и на расстоянии от неё вглубь металла, использовали рентгено-флуоресцентный масс-анализ и производили измерения твёрдости с помощью прибора Nanoindentor G200. Выполнены сравнительные измерения относительных концентраций элементов в составе поверхности стали после бомбардировок различными ионами (Ti или Мо), а также получены профили залегания внедрённого в металл азота и модифицированной твёрдости. Выявлены особенности в результатах азотирования стальной поверхности при использовании разных сортов ионов. Фотографии поперечных шлифов, полученных с помощью оптического металлографического микроскопа ММО 1600, продемонстрировали отличия в структурных характеристиках приповерхностных слоёв при бомбардировках ионами титана и молибдена. Эти отличия связаны с повышенной температурой в слоях при бомбардировке ионами молибдена. Целью настоящей работы является проведение сравнительных экспериментов по обработке стальных поверхностей ускоренными ионами разных металлов с последующим анализом влияния таких воздействий на процессы азотирования этих поверхностей.

Background. Conducting targeted research to improve the quality of metals and their effective use is important in the world, with special attention paid to the following tasks: the use of watersoluble, organic inhibitors to combat scale formation, determination of optimal conditions for the inhibition of corrosion of metals. Purpose. Creation of new highly effective inhibitors based on nitrogen-containing compounds to prevent corrosion of steel in acidic medium and investigation of the mechanism of their action. Methodology. In work gravimetry, IR spectroscopy, X-ray structural analysis as well CE 105 corrosiometer. Originality. Mechanisms of action of organic inhibitors with chromium-containing compounds have been proposed, general regularities have been established affect the effectiveness of steel protection against corrosion in their presence. Findings. The results of the study are that the mechanism of protection of organic inhibitors has depended on their structure and physico-chemical characteristics. [ABSTRACT FROM AUTHOR]

Background. At present, the urgent problem facing the mining and metallurgical industry of Uzbekistan is increasing the complexity of the use of raw materials, extracting valuable components from man-made waste, involving them in processing. Technogenic raw materials of ferrous metallurgy in the form of steelmaking slag are subjected to enrichment, but the concentrate obtained in this case has a too small fraction, which cannot be loaded into the metallurgical furnace due to large losses by the gas flow. To avoid dust carry-over, the technogenic raw material of fine fraction after its enrichment can be processed into a valuable product, iron ore coal metallized pellets used in the form of raw materials in steel smelting. Purpose. Processing of man-made waste in the form of furnace steel-making slag, with the receipt of iron ore coal metallized pellets, which can be used as raw materials for steel melting. Methodology. To determine the degree of enrichment of furnace slags by the jigging method, experiments were carried out in a laboratory two-chamber diaphragm jigging machine MOD-2. And also was studied the washability of furnace slag on one level concentration table of the LKS -1Ya grade. The effectiveness of the reducing ability of coke and Angren coal for iron oxides was carried out in a laboratory furnace. Originality. The optimal indicator of the size of steel-making slags for the extraction of iron and its compounds from ferrous metallurgy slags by the method of gravity concentration has been determined. The physicochemical processes occurring during the heat treatment of ore-fuel pellets in a reducing environment have been determined. Findings. As a result of research and development, a method has been developed for processing steel-making slag, which makes it possible to obtain an additional amount of raw materials for steel smelting, as well as the use of production residues in the construction industry. [ABSTRACT FROM AUTHOR]

In the metal structures that are subjected to significant mechanical and radiation loads during their operation, structural alterations occur, which are unevenly distributed over the depth of the material. Materials with a modified surface, including thin coatings and multilayers, are equally challenging objects for structural studies. The development of methods for depth-selective layer-by-layer X-ray diffraction diagnostics is a nontrivial task aimed at controlling the effective depth of the collection of structural information. The most developed approaches to date include: (a) asymmetric (glancing-angle) geometry and (b) the use of primary radiation with different penetrating power. In both cases, calibration procedures with coatings or two-layer systems of known thickness are required to determine the thickness of an effectively reflective layer. In this work, we have studied the possibilities of X-ray diffraction examinations of steel and iron samples with a thin (micron) copper coating. The thickness of the copper coating was estimated from the intensity decrease of the iron substrate’s diffraction lines. With the use of asymmetric (glancingincidence) measurements, the conditions for the disappearance of lines from the substrate were established, which made it possible to estimate with acceptable accuracy the thickness of the steel layer participating in the formation of the diffraction pattern. The method of the depth-differentiated estimation of the structural characteristics of the "interface" and conditionally "bulk" regions of the α-Fe substrate by using polychromatic cobalt radiation is tested. The limitations of this approach and the possibility of its application to a wider range of steels are discussed. The considered aspects of X-ray diffraction studies of model systems of the "steel-coating" or "steel-modified surface" type are important in the study of surface radiation-stimulated structural alterations in steels of power engineering. [ABSTRACT FROM AUTHOR]

A mathematical physical based semi-empirical model and a corresponding computer program are developed for describing recrystallization process and carbonitrides particles precipitation in deformed austenite. The model is suitable for alloyed steels of a wide range of compositions. The model allows calculating a thermodynamic equilibrium for carbonitride excess phases with solid solution, the kinetics of their nucleation and growth, and their effect on recovery and recrystallization. A detailed description is given for each aspect of the model and its physical nature. Verification of the simulation results with the experimental data taken from published sources confirms the sufficient reliability of the proposed computer model for evaluative calculations. The model's features are demonstrated by an example that simulates influence of Nb content on recristallization, recovery and nucleation, growth and Ostwald ripping of Nb and Ti carbonitride particles. The simulation shows and numerically predicts the effect of slowing down recrystallization and recovery with increasing in Nb content. That attests significance of the effect of dispersed carbonitrides on recrystallization and recovery. The simulation theoretically predicts an intensification of Ti(C, N) particles precipitation and growth with an increase in the Nb concentration. As another result, it is an increasing the dispersion and number of Nb(C, N) particles with an increase in the Nb concentration owing to more rapid transition to the Ostwald ripening stage, which is characterized by much more slowly average particle size growth than from a supersaturated solid solution. [ABSTRACT FROM AUTHOR]

Copyright of Mechanics & Advanced Technologies is the property of National Technical University of Ukraine KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A mathematical physical-based semi-empirical model and a corresponding computer program are developed for describing recrystallization process and carbonitrides particles precipitation in deformed austenite. The model is suitable for alloyed steels of a wide range of compositions. The model allows calculate a thermodynamic equilibrium for excess carbonitride phases with solid solution, the kinetics of their nucleation and growth, and their effect on recovery and recrystallization. A detailed description is given for each aspect of the model and its physical nature. Verification of the simulation results with the experimental data from published sources confirms the sufficient reliability of the proposed computer model for evaluative calculations. The model's features are demonstrated by an example that simulates influence of Nb content on recristallization, recovery and nucleation, growth and Ostwald ripening of Nb and Ti carbonitride particles. The simulation shows and allows numerically evaluate the effect of slowing down recrystallization and recovery with increasing in Nb content. This indicates a significant effect of dispersed carbonitrides on recrystallization and recovery. The simulation theoretically predicts an intensification of Ti(C, N) particles precipitation and growth with an increase in the Nb concentration. Another result is an increase of dispersion and number of Nb(C, N) particles with an increase in the Nb concentration owing to more rapid transition to the Ostwald ripening stage, which is characterized by much more slowly average particle size growth than from a supersaturated solid solution. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By the method of polarization measurements there have been investigated the corrosion-electrochemical properties of steel 09G2S which was obtained by means of the powder metallurgy. Similar measurements were carried out for compact steel in order to compare the obtained data. Anodic and cathodic curves taken in the sea water showed that corrosion-electrochemical properties of both steels were identical, i.e. both cathodic and anodic processes on these steel samples proceed according to the same mechanism with the only difference that currents observed on the powder electrode are almost 2.5 times up from those on the compact electrode. It revealed that the corrosion rate of powder steel is also up 2.5 times from that on the compact steel. Corrosion-electrochemical studies into sulfate solutions with different pH values showed that as pH increases, the stationary potentials of steels shifts to the negative side while rates of cathodic and anodic processes decrease. To our thinking, the transition regions on anodic curves result from the competing adsorption between OH- and SO2-4 ions. The higher dissolution rates of the powder electrode in the investigated solutions are, on the one hand, due to high true surface of the powder steel and to non-equipotentiality of surface specified steel, on the other hand. [ABSTRACT FROM AUTHOR]

The possibility is considered of producing a steel-titanium joint which forms at complex spray-deposition of a layer of aluminium oxide and a layer of iron powder PZh-1 on titanium with subsequent deposition by a consumable electrode or plasma of a layer of steel using filler wire Zv-08G2S. A new combined method was developed for joining steel to titanium with deposition of protective layers of Al2O3 and iron powder PZH-1 on titanium, with further deposition of a layer of filler wire Zv-08G2S by the plasma process. Ref. 8, Tabl. 2, Fig. 8. [ABSTRACT FROM AUTHOR]

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction. Chemical decorative treatment of steel consists in painting steel products and applying oxide films to the surface to create an attractive appearance and prevent the product from rust. Staining copper organic compounds with aqueous solutions has the following feature: the coating color varies depending on the resistance time in solution, which is associated with changing in thickness of the forming oxide layer where interference phenomena occur. For a wide application of this method, studies are needed to investigate the relationship between the staining modes and the resulting coating color. The work objective is to establish relationship between the coating staining obtained from alkaline copper-containing solutions and their quantitative and qualitative phase composition. Materials and Methods. The phase composition of the coatings obtained was studied by the method of local electrochemical analysis (LEA) based on the cathodic reduction of the oxide phases of the coatings in the galvanopulse mode using a clamp sensor. From the obtained impulse chronopotentiograms, the potential values at the pause moment were considered, and then these values were compared to the standard potentials of various redox pairs of copper oxides. Research Results. The analyzed coatings were formed during different time of holding the sample in solution and had a different color. The data of the redox pair correspond to: [[Сu(OH)4]2-/Cu - adsorption layer of hydroxocuprate-anions on the surface of electrodeposited copper steel; Cu(OH)2/Cu - adsorption layer of copper hydroxide on the surface of electrodeposited copper; Cu2О/Cu - oxide film of copper oxide (I) on copper. This equates to conclude about the colored coatings composition on the samples studied. Brown, violet and blue films formed during the initial period of exposure of the copper coating in solution contain adsorbed hydroxocuprate and copper hydroxide. Blue, yellow and lilac films formed over a longer period of time contain, in addition to these phases, copper oxide (I). Discussion and Conclusions. From the data obtained, it follows that the management of the color change time required in various technological applications can be carried out through changing the concentration of copper sulfate, as well as an organic reducing agent. The mechanism of coating coloration is affected by the adsorption layers formed on the steel surface. By varying the aging time of the sample in the electrolyte, it is possible to control the phase composition of the adsorption layers, and, consequently, influence the coating colorability.

The hydrogen removal from electrolytically hydrogenated samples of two different steels (ferritic and austenitic) was experimentally studied. The temperature dependences of hydrogen evolution were obtained using the set-up with hot vacuum extraction and mass spectrometric registration of the volatile components. For both steels, the process of hydrogen evolution can be described as consisting of two stages, which are overlapped with different degrees of resolution. In assumption that each moiety is related to a certain form of hydrogen in material (specific trapping site), the kinetic parameters of the process of the gas extraction were estimated for two stages of both samples. The similarity of the kinetic parameters of the first stage indicates the same form (or location) of hydrogen in both steel samples. This is believed to be surface localized hydrogen. The kinetic parameters of the second (“high temperature”) stage have more significant differences, which may indicate different kinetics of the thermally stimulated removal of hydrogen from the near-surface layers of α-Fe and γ-Fe. These parameters can serve as markers of the localization of hydrogen in various steels and allow one to compare the ratios of different forms of hydrogen in such materials. [ABSTRACT FROM AUTHOR]

The paper provides the results of analytical review of researches and commercial application of electroslag welding and surfacing in Ukraine as well as foreign countries from the beginning of XXI century. The analysis showed that volume of application of electroslag welding of large thickness metal (more than 100 mm) in different branches of industry noticeably reduced, however, stable growth of its application in the recent years is noted in construction of bridge and high-rise buildings, ship building as well as repair of large parts of machines on-site. New steels have low sensitivity to grain growth in a heat affected zone, allowed expanding range of products made by electroslag welding. There is a considerable increase of volume of application of electroslag surfacing with strip electrode for anticorrosion coatings in pressure vessels, separators, steam generators, compressors and other equipment, being operated in oil and gas, power, metallurgical, paper-and-pulp and chemical industries. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Diagnostics & Nondestructive Testing / Tekhnicheskaya Diagnostika I Nerazrushayushchiy Kontrol is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The weapon has always been not only a means of warfare, but also the subject of the historical, cultural, technological heritage of any nation. Scientific achievements, technological and cultural innovations are realized in the weapon. Medieval Europe is rich in technological invention in the field of gunsmiths. Especially a lot of inventions relate to the manufacture of cold blade weapons. Through attempts and mistakes, medieval gunsmiths found the best possible variants of the material from which the weapon was made. Perhaps in the greatest degree this concerns the production of swords. In the Middle Ages, the sword was something more than a weapon. It was still a subject of status, prestige and art. Therefore, the gunner paid special attention to its manufacture. The sword provides the key to understanding the emergence and further evolution of all medieval weapons, and even more– phenomenon of European militaristic cultures. [ABSTRACT FROM AUTHOR]

The analysis of the historical development of the of metal structures in Art Nouveau style in relation to the previous era of eclecticism was carried out. It revealed three approaches to shaping the metal for use in load-bearing structures for creating expressive interior environment: constructive-technological, constructive-decorative, constructive-imaginative. The employment of metals in the interior in the style of Art Nouveau is systematized by the material and method of applying.