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To quickly obtain the fatigue life of cranes in service, the metal structure that determines the crane life is anchored. Meanwhile, the fast prediction method of fatigue life of crane metal structures based on the Stacking ensemble learning model is proposed. Firstly, in line with the structural stress method, the global rough model of the metal structure is established by the co-simulation technology to obtain the fatigue damage regions of the structure. The local fine model is constructed by local cutting and boundary condition transplantation to determine the critical weld at the failure regions. Secondly, through weld definition, equivalent structural stress acquisition, and fatigue life calculation, the sample data set with lifting load and trolley running position as input and fatigue life cycle times as output is constructed. Then, the Stacking integrated learning model combining gradient boosting, ridge regression, Extra Trees, and linear is built. On this basis, combined with the Miner theory, the rapid prediction of crane fatigue life is realized. Finally, the proposed method is applied to the QD40t × 22.5 m × 9 m general bridge crane. The results show that the life sample set constructed by the structural stress method is more accurate and reasonable than the nominal, hot spot, and fracture mechanics methods. The life prediction results of the Stacking integration model were improved by 6.3 to 49.2% compared to the single model. The method has theoretical and practical significance in reducing accidents and ensuring the safe operation of cranes. [ABSTRACT FROM AUTHOR]

The results of modeling and research of casting, rolling, and extrusion processes for producing wire from AleZr system alloys and determining its physical and mechanical properties have been presented. When implementing combined processes for processing aluminum alloys, the number of operations is significantly reduced, productivity and yield are increased. As a result of the conducted research, the influence of alloy preparation modes and their chemical composition on the physical, mechanical and electrical properties of longish semifinished products from AleZr system alloys obtained by combined rollingextrusion (CRE) and ingotless rolling-extrusion (IRE) methods were investigated. The simulation of the CRE process for one of these alloys of the system was carried out in the DEFORM 3D software package using data on its rheological properties obtained by the hot torsion method. Based on the modeling results, the optimal modes for conducting experimental studies were selected. The features of metal forming were experimentally studied, the temperature-velocity and technological parameters of combined processing were found, as well as the properties of cast billets, including those obtained using an electromagnetic mold (EMM). The results of experimental studies of the CRE and IRE processes suggest that it is possible to obtain longish deformed semifinished products from alloys AleZr system with a level of physical, mechanical and electrical properties that meet international standards. At all technological stages, including drawing, the structure of the metal was studied, and data on the physical and mechanical properties of hot-extruded rods and wire in cold-deformed and annealed states was obtained. The heat resistance of wire made from the investigated alloys was studied and it was found that after testing at a temperature of 280 °C and a holding time of 1 h, it satisfies the requirements of the AT3 type standard with a maximum permissible long-term operating temperature of 210 °C. Recommendations are given for industrial implementation; alloys containing 0.15e0.20% zirconium and 0.10e0.15% iron are recommended for the manufacture of AT1 type wire without heat treatment, as well as 0.25e0.30% Zr and 0.2e0.25% Fe for AT3 wire type with heat treatment. [ABSTRACT FROM AUTHOR]

The current study investigates the development of a replica molding process for hypervariable microstructures. Initially, the mold deformation theory for these hypervariable microstructures was derived. Based on this theory, a metal material with magnetic properties was selected as the structural material to create a negative Poisson's ratio (NPR) geometric structure. The experimental results, obtained by fabricating the NPR geometric mold layer with a metal material with adjustable magnetic properties and controlling microstructure deformation indirectly, validate the deformation theory and its predictions. These results demonstrate that the developed molding process, integrated with the magnetic NPR regulation system, exhibits excellent stability and replication capability. In this study, at the zero height (z = 0) position on the interface between the NPR geometric structure layer and the Polydimethylsiloxane (PDMS), the variation becomes more pronounced with increasing distance from the center of the microstructure. Furthermore, the tendency of the function curve varies accordingly. The primary cause is the lack of constraints on the free ends of both sides and the excessive constraints on the intermediate parts. Under the conditions in this study, the maximum ratio of its influence on the radial diameter thickness was 2.1%. This innovative process facilitates the rapid imprinting of microstructural components and offers the advantage of efficient molding. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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 Proceedings in Archeology & History of Ancient & Medieval Black Sea Region is the property of Cimmeria Publishing 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 behavior of a structure under the influence of external factors is determined by three key groups of parameters the metal composition (chemical, structural, and deformation). Obtaining information about these parameters directly on the structure will effectively solve the problem of assessing its actual technical condition. The problem of nondestructive evaluation of the chemical composition of metal is solved using portable spectrometers. A Microlab-Z2 diagnostic complex has been developed to evaluate the other two groups of parameters. It has two functional blocks. The surface preparation unit ensures that the surface of the construction site has a roughness, flatness, and level of applied mechanical hardening corresponding to the laboratory preparation of metallographic specimens. The research unit is a platform on which a metallographic microscope and a portable microhardness tester are installed. It allows metallographic research with magnification up to ×1000, surface microindentation, measurement of microhardness values at load of 0–200 gf, and optical study of the morphology of imprints in any spatial position. The reliability of the data obtained by the Microlab-Z2 diagnostic complex has been confirmed during comparative tests with stationary equipment. An assessment of structure parameters and contamination of metal with nonmetallic inclusions, assessment of the degree of hardening and embrittlement of metal, and detection of aging processes can be performed with the help of the developed device. The use of the Microlab-Z2 diagnostic complex for operational nondestructive evaluation of structural and deformation parameters of metal structures will allow reaching a qualitatively different level of efficiency in performing production and acceptance testing of manufactured products, assessing the maintainability of defects, planning repairs and other compensating measures, and industrial safety expertise. [ABSTRACT FROM AUTHOR]

This article presents the study of the effect of ultrafine titanium monocarbide (TiC) powder on the formation of the deposited metal structure. The effective particle size of the powder for the welding bath inoculation of low-carbon and low-alloy steels should be at least 600–700 nm (0.6–0.7 μm). The use of an inoculator powder with a more dispersed fraction was inappropriate from thermodynamic and economic points of view. With the increase in the content of ultrafine TiC powder in the coating of welding electrodes (0%–10%), the crystallites in the deposited metal decreased in size by 8–9 times, and they acquired a more equilibrium state (the shape factor increased by two times). The addition of various amounts of TiC powder to the melt of the welding bath did not result in a noticeable hardening of the deposited metal (Vickers hardness: 188–197 HV). [ABSTRACT FROM AUTHOR]

Coating, as one of the significant applications in the building and construction sector, is crucial to prevent steel from reaching critical temperature and fire-induced structural collapse. This article reviews the current use of conventional coatings and assesses the potential use of novel geopolymer coatings on the metal substrate, particularly on the steel structure. The conventional passive fireproofing systems, including cement-based coatings and intumescent coatings, exhibit unavoidable limitations either due to the high thickness and weight or poor thermal and chemical resistance of the coating. Thus, innovations in conventional and novel coatings are constantly developing and growing rapidly. In recent years, geopolymer coatings have attracted much attention due to their higher mechanical strength and excellent resistance to chemicals and heat. Moreover, the green and environmentally friendly characteristics make geopolymer an admirable coating material for many applications. The main challenge that lies in the development of geopolymer coating is the interfacial bonding with the metal structure. Therefore, the influencing factors, including precursor materials, alkaline activator, and curing processes on the adhesion and thermal and chemical resistance of the geopolymer coating have been well explored. The performance comparison between these coatings indicates that geopolymer coating offers a superior mechanical and thermal performance, along with a substantially lower environmental impact compared with cement-based coating. This suggests that geopolymer coatings have great potential for fire protection on steel structures. [ABSTRACT FROM AUTHOR]

This article presents the results of the analysis of the patent situation in the field of 3D printing technologies with metals and materials based on them and the prospects for their development. In the development of the life cycle of patenting laser additive technologies in Russia in 2000–2020, three main stages can be distinguished, namely, Stage I for 2000–2008, Stage II for 2009–2015, and Stage III for 2016–2020. In terms of the applicability of patent solutions in the field of laser additive technologies, the most developed industries are the mechanical engineering and metallurgical industries. The leaders of patenting in the Russian Federation territory are BASF and Siemens (Germany) and Airbus Operation (France). The leading countries where applicants strive to obtain patents are the USA, Russia, China, Japan, and the countries of the European Union. Three main directions can be distinguished among the main trends in the development of laser additive technologies: development of basic cultivation technologies (development of effective technological modes) of products and technologies of combined processing (e.g., deformation, thermal, and thermal–deformation); development of devices and equipment for additive manufacturing, including special equipment that ensures high-quality geometric parameters and improves the performance properties of the product during the production process; and development and creation of new powder materials and their compositions with a given granulometric composition and technologies for their production. [ABSTRACT FROM AUTHOR]

Copyright of VLC Arquitectura is the property of VLC Arquitectura 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 Yellow River is the property of Editorial Board of Yellow River 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 Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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. Analyzing the stress distribution in the metal structure of the gantry crane under the cyclic operation mode and identifying stress concentrators in the crane column to assess the survivability of the machine. Methodology. In order to achieve the objective, the methods employed included analytical calculation method, finite element method, as well as differential and integral calculus methods. To study the state of the metal structure of the gantry crane, namely the column, the program Solid Works and its application Simulation were used. Findings. Using the CAD/CAE-system, the loaded condition of the metal structure of the gantry crane was modeled and the maximum working loads were determined, and a calculated scheme of their operation was constructed. The method is presented for calculation of survivability of load-bearing elements of the crane taking into account coefficients of intensity and concentration of stresses which allow defining speed of growth of cracks in dangerous stress zones of a metal structure. Originality. The existing methods for designing crane metal structures gained their traction. The integrated technique for assessing crane reliability has been suggested for the first time. This technique is focused on estimating the survivability of components elements. For the first time solid-state models of the crane and its column have been developed; the analysis of the stress-strain state of the column was performed, maximum stresses were determined, stress concentration points in the metal structure of the column were identified and recommendations for improvement of stress zones were presented. Practical value. The presented method for assessing the reliability of metal structures of gantry cranes can be implemented in the practice of design organizations for the development, design of new gantry cranes and modernization of existing ones. The obtained results provide an opportunity to assess the accumulated damage in the elements of the metal structure, to predict the development of defects to a critical size, as well as to decide on the further operability of a gantry crane. [ABSTRACT FROM AUTHOR]

Features of centrifugal plasma surfacing using powders of three different alloying systems based on iron and nickel were studied. It is found that at centrifugal plasma surfacing the iron-based test powder has the best welding-technological properties. It allows producing deposited metal of 200Kh15D2MS2R type. The layer deposited with this powder, has a microstructure of uniform height and ensures increase of the sleeve wear resistance 5-6 times, compared to batch-produced ones, which are made from steel 70 and "uenched by HFC. A design of the bushing component is proposed with replaceable surfaced sleeve, which is more adaptable to fabrication and allows repairing it by simple replacement of the worn sleeve. [ABSTRACT FROM AUTHOR]

The results of studies of the process of obtaining wire for the manufacture of jewelry chains from new nickel-free 585 gold fineness alloys are presented. New 585 gold fineness alloys, alloyed with palladium, silver and other elements, and as modifiers – with rhodium and ruthenium in the stated quantities have been proposed. By modeling the process of section rolling of rods in octagonal calibers using the variation method of minimum total power, the broadening of the metal and the energy-power parameters of rolling rods from the investigated alloys have been determined. The regularities of their change have been found. Software has been developed for designing processes for the production of longish deformed semi-finished products and technological modes of rolling and drawing of new gold alloys. With the help of experimental studies, the adequacy of the results of calculations and modeling was checked, and new data were obtained on the mechanical properties of the metal and its structure. It has been found that the proposed alloys and the modes of their processing using the processes of section rolling and drawing make it possible in industrial conditions to obtain jewelry wire with a diameter of up to 0.25 mm with the level of mechanical and operational properties required for chain tying. [ABSTRACT FROM AUTHOR]

Features of centrifugal plasma surfacing using powders of three different alloying systems based on iron and nickel were studied. It is found that at centrifugal plasma surfacing the iron-based test powder has the best welding-technological properties. It allows producing deposited metal of 200Kh15D2MS2R type. The layer deposited with this powder, has a microstructure of uniform height and ensures increase of the sleeve wear resistance 5 – 6 times, compared to batch-produced ones, which are made from steel 70 and quenched by SHF. A design of the bushing component is proposed with replaceable surfaced sleeve, which is more adaptable to fabrication and allows repairing it by simple replacement of the worn sleeve. [ABSTRACT FROM AUTHOR]

Proceeding from published data, the influence of modification and microalloying by boron, titanium, tungsten, zirconium, yttrium, etc., on the deposited metal structure, mechanical and service properties is shown. It is demonstrated that addition of these elements or their compounds with carbon and nitrogen in the quantity of up to 0.2 %, allows producing a fine-grained, homogeneous structure of metal, a more uniform distribution of alloying elements, that makes a positive effect on the values of strength, ductility, wear and heat resistance. It was determined that introducing small additives of boron or its compounds (in the quantity of up to 0.2 %), cerium or yttrium (in the quantity of up to 0.015 % of each), or application of complex master alloys, which can have the above-mentioned elements in their composition, as well as such modifiers, as zirconium, titanium carbides and borides or tungsten carbides, looks promising in terms of increase of wear and heat resistance of the deposited metal. Proceeding from the performed analysis, it was also shown that addition of titanium and zirconium diborides to the composition of flux-cored wire charge, promotes activation of the processes of formation of molten metal drops at the electrode wire tip, resulting in improvement of the quality of metal transfer in the welding arc that leads to greater values of the coefficients of alloying element transition into the deposited metal and improves deposited bead formation. [ABSTRACT FROM AUTHOR]

Proceeding from published data, the influence of modification and microalloying by boron, titanium, tungsten, zirconium, yttrium, etc., on the deposited metal structure, mechanical and service properties is shown. It is demonstrated that addition of these elements or their compounds with carbon and nitrogen in the quantity of up to 0.2 %, allows producing a fine-grained, homogeneous structure of metal, a more uniform distribution of alloying elements, that makes a positive effect on the values of strength, ductility, wear and heat resistance. It was determined that, introducing small additives of boron or its compounds (in the quantity of up to 0.2%), cerium or yttrium (in the quantity of up to 0.015 % of each), or application of complex master alloys, which can have the above-mentioned elements in their composition, as well as such modifiers, as zirconium, titanium carbides and borides or tungsten carbides, looks promising in terms of increase of wear and heat resistance of the deposited metal. Proceeding from the performed analysis, it was also shown that addition of titanium and zirconium diborides to the composition of flux-cored wire charge, promotes activation of the processes of formation of molten metal drops at the electrode wire tip, resulting in improvement of the quality of metal transfer in the welding arc, that leads to greater values of the coefficients of alloying element transition into the deposited metal and improves deposited bead formation. 28 Ref., 1 Tabl., 7 Fig. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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 literature review of the main methods of modification and microalloying of deposited metal was made. It was shown that, in contrast to the «microalloying» term, the «modification» term should mean not only a method of introducing small additives of chemical elements or their compounds into the deposited metal but also various physical effects or technological processes aimed at achieving the same goal - refinement of micro- and macrostructure of metal, cleaning of grain boundaries and near-boundary zones, improving the complex of technological, mechanical and operational properties of steels and alloys. Examples of such physical effects are application of vibrations to a product in the process of surfacing; input of energy from a pulsed heat source; pulsed electrode or filler wire feed; application of sources with modulation of welding current; external electromagnetic effect, etc. The classification of modification methods, depending on the scheme of their implementation and impact on the properties of the deposited metal is given. The main advantages and disadvantages of methods of introducing modifying and microalloying additives into the deposited metal are shown. It was determined that from the considered methods of modification, the chemical method is the simplest and the most rational, which implies introducing modifiers into the deposited metal directly through the charge of flux-cored electrode wires. This method is technologically and economically simple and versatile, and can be used with minor changes in electric arc, electroslag and plasma surfacing. 33 Ref., 1 Table, 3 Figures. [ABSTRACT FROM AUTHOR]

A literature review of the main methods of modification and microalloying of deposited metal was made. It was shown that, in contrast to the term «microalloying», the term «modification» should consider not only a method of introducing small additives of chemical elements or their compounds into the deposited metal but also various physical effects or technological processes aimed at achieving the same goal – refinement of micro- and macrostructure of metal, cleaning of grain boundaries and boundary zones, improving the complex of technological, mechanical and operational properties of steels and alloys. Examples of such physical effects are application of vibrations to a product in the process of surfacing; input of power from a pulsed heat source; pulsed electrode or filler wire feed; application of sources with modulation of welding current; external electromagnetic effect, etc. The classification of modification methods depending on the scheme of their implementation and impact on the properties of the deposited metal is given. The main advantages and disadvantages of methods of introducing modifying and microalloying additives into the deposited metal are shown. It was determined that from the considered methods of modification, the chemical method is the simplest and the most rational, which implies introducing modifier elements into the deposited metal directly through the charge of flux-cored electrode wires. This method is technologically and economically simple and versatile, and can be used with minor changes in electric arc, electroslag and plasma surfacing. 33 Ref., 1 Tabl., 3 Fig. [ABSTRACT FROM AUTHOR]

Friction stir welding may be used to create butt joints of an aluminum matrix composite dispersion-hardened by SiC particles. With increase in content of the reinforcing SiC particles, the range of welding conditions producing defect-free joints is significantly narrowed. In cyclic loading, the joints begin to fail from the weld surface. [ABSTRACT FROM AUTHOR]

The results of the first stage of ultrasonic studies of the metal structure of pipelines of thermal power plants in operation are presented. The tests were carried out on metal of steel grades 15Kh1M1F and St20 with different operating life (operating time). The metal samples were subjected to metallographic analysis, the received data (the average grain size the distribution variance ) was used for theoretical calculation of the parameters of ultrasonic pulses of the bottom signal in metal. Quantitative data were obtained on the effect of the thickness of the couplant layer (the gap) between the transducer and the test object at operating frequencies of 5.0, 7.5 and 10 MHz for various values of the average grain size in metal. Examples of calculated and experimental pulses and signal spectra for a frequency of 5 MHz are given. [ABSTRACT FROM AUTHOR]

The paper presents the results of studies of the structure and properties of a wire with a diameter of 0.5 mm from an alloy of the Al-REM system with a rare-earth metal content of 7–9%. Wire obtained as a result of the implementation of the technology of its manufacture using the methods of casting into an electromagnetic mold (EMM), continuous extruding, and drawing. The rheological properties of the metal of continuously cast round billets from the experimental alloy obtained using an electromagnetic mold are determined. The modeling and analytical assessment of the possibility of carrying out the process of combined rolling-extruding (CRE) of such billets in a closed box-type roll groove of a continuous extruding unit are carried out. The features of metal shaping have been studied. The temperature-speed and technological parameters were found at which the CRE process can be carried out in a stable mode of operation. Data have been obtained for the forces acting on the die and rolls during rolling-extruding. The results of experimental studies of the process of obtaining longish deformed semi-finished products from an experimental alloy on the laboratory unit CRE-200 and the pilot plant unit CRE-400 are presented. The structure of the metal has been studied; data on the ultimate tensile strength, yield strength, relative elongation, and electrical resistance of hot-extruded rods and wires in cold-worked and annealed states have been obtained. It was found that the proposed processing modes make it possible to obtain by the method of combined rolling-extruding rods with a diameter of 9 mm in industrial conditions from longish billets with a diameter of 18 mm, cast by means of EMM. Wire in a cold-deformed and annealed state with a diameter of 0.5 obtained by drawing from the rods with a diameter of 9 mm from an experimental alloy of the Al-REM system containing 7–9% rare-earth metals with the required physical and mechanical properties. [ABSTRACT FROM AUTHOR]

Copyright of Revista Sul-Americana de Engenharia Estrutural is the property of Revista Sul-Americana de Engenharia Estrutural 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 method for assessing the condition and residual life of water-path metal structures of hydraulic turbines is described using runner chambers and penstocks of hydroelectric power plants (HPP) as an example. Applications of the method are exemplified. [ABSTRACT FROM AUTHOR]

The effect of thermal cycles of arc welding on the structure and mechanical properties of metal of the heat-affected zone of welded joints of microalloyed structural steels of the strength class from c350 to c490 was investigated. it was established that as a result of the action of thermal cycles of welding, metal structure of the heat-affected zone of most microalloyed steels of the strength class from C350 to C490, except for steel 09g2syuch, remains stable bainite in a wide range of cooling rates, and mechanical properties do not change significantly. as a result of welding, at moderate cooling rates the structure of the heat-affected zone metal in the steel 09G2SYuch can change from bainitic to bainito- martensitic and martensitic as the metal cooling rate increases. as a result of that, the values of static strength and impact toughness of the metal are increasing and its ductile properties are reduced. [ABSTRACT FROM AUTHOR]

The effect of thermal cycles of arc welding on the structure and mechanical properties of metal of the heat-affected-zone of welded joints of microalloyed structural steels of strength class from C350 to C490 was investigated. It was established that as a result of the action of thermal welding cycles, the metal structure of the heat-affected-zone of most microalloyed steels of strength class from C350 to C490, except for 09G2SYuch steel, remains stable bainite in a wide range of cooling rates, and mechanical properties do not change significantly. As a result of welding, at moderate cooling rates the structure of the heat- affected-zone metal in the steel 09G2SYuch can change from bainite to bainite-martensitic and martensitic as the metal cooling rate increases. As a result of that, the values of static strength and impact toughness of the metal are increasing and its ductile properties are reduced. [ABSTRACT FROM AUTHOR]

Cast iron is one of the main structural materials, having a number of valuable service properties, in particular, wear resistance. Improvement of this characteristic is usually achieved by changing the structure of cast iron due to introduction of expensive alloying elements into its composition. The experiments carried out showed the possibility of transforming gray low-alloy cast iron to chilled wear-resistant one, due to modification of the deposited metal by small portions of tellurium powder. Electroslag surfacing was carried out in a current-carrying mold with melting of filler in the form of chips of low-alloy cast iron in the slag layer and additionally introducing flux-cored wire with a charge, containing tellurium powder, into the slag pool. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office 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 Automatic Welding / Avtomatitcheskaia Svarka 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 influence of introducing tungsten and tungsten concentrate in powder-core wire on the structure, microhardness of the structural components, hardness, and wear of the applied metal layer is studied. For surfacing, tungsten-bearing powder wire (types H and E in the IIW classification) is produced in the laboratory. The fillers employed are KR-1 silicon powder (State Standard GOST 2169–69); MR-0 manganese powder (State Standard GOST 6008–82); PKhA-1M chromium powder (Technical Specifications TU 14-1-1474–75); VEL-1 vanadium (Technical Specifications TU 48-0533–71); PNK-1L5 nickel (State Standard GOST 9722–97); PAP-1 aluminum (State Standard GOST 5494–95); PVT tungsten (Technical Specifications TU 48-19-72–92); and PZhV-1 iron powder (State Standard GOST 0489–96). In some wire, tungsten powder is replaced by KSh-4 tungsten concentrate (State Standard GOST 213–83), produced by OAO GK AIR. The carbon-bearing reducing agent employed is gas-purification dust from aluminum production. Its composition is as follows: 21.00–43.27 wt % Al2O3, 18–27 wt % F, 8–13 wt % Na2O, 0.4–6.0 wt % K2O, 0.7–2.1 wt % CaO, 0.50–2.48 wt % SiO2, 2.1–2.3 wt % Fe2O3; 12.5–28.2 wt % Ctot; 0.03–0.90 wt % MnO, 0.04–0.90 wt % MgO, 0.09–0.46 wt % S, and 0.10–0.18 wt % P. The wire (diameter 5 mm) is produced on laboratory equipment. An ASAW 1250 system is used for surfacing, in the following conditions: Is = 400–450 A; Uarc = 32–36 V; Vs = 24–30 m/h. In surfacing, five metal layers are applied, under a layer of AN-26S flux and flux based on slag from silicomanganese production. The chemical composition of the applied metal is determined, and metallographic data are obtained: the size of the former austenite grain, the size of the martensite needles, and the content of nonmetallic inclusions are determined. Wear tests are conducted, and the hardness and microhardness are measured. The use of tungsten concentrate instead of tungsten powder in surfacing is shown to be possible in principle. The degree of tungsten extraction is calculated. For type-H wire, the replacement of tungsten powder by tungsten concentrate does not increase the content of nonmetallic inclusions in the metal layers applied; the primary austenite grain size is decreased. For type-E wire, the use of tungsten concentrate tends to decrease the primary austenite grain size and the size of the martensite needles and also increases the microhardness of martensite within the applied layer. The replacement of tungsten powder by tungsten concentrate in class-H wire considerably increases the hardness and wear resistance of the applied layer. [ABSTRACT FROM AUTHOR]

Copyright of Automatic Welding / Avtomatitcheskaia Svarka 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.)

Abstract: The production of a solid-phase diffusion bond in OT4-1 alloy on the basis of a cold forced fit of components in a shaft-hole configuration is considered. The influence of the maximum stress-strain state in the cold forced fit and subsequent heat treatment (in autonomous vacuum) on the structural evolution and properties of the contact region is investigated. In cold plastic deformation of the alloy with the formation of a solid-phase diffusion bond, deformational relief (traces of grain-boundary slip) is observed in the microstructure of the contact region. In addition, decrease is noted in the area of the contact surfaces, and fewer bulk interactions are noted in the contact plane (grain distortion) and in the contact volume (regions of dislocation departure). The basic characteristics of the structural interface—the unit parameter of structural organization, the grain density, the mean grain-boundary density, and the development of the grain boundaries—exceed by factors of 10, 4, 1.8, and 1.5, respectively, those of the basic metal in the initial state. Heating in autonomous vacuum in the range of α → β phase transitions leads to stepwise structural changes in the basic metal and in the contact region of the solid-phase diffusion bond. Initially, a globular component appears in the microstructure. With further heating, this component reverts to the initial acicular structure (with some increase in microhardness). The formation of globular structure on heating plastically deformed metal is observed not only at temperatures corresponding to phase transition but also at higher temperatures; this has not previously been noted. With increase in temperature, the duration of this stage decreases. In addition, with less developed plastic deformation, the formation of globular structure is observed close to the polymorphic-transformation temperature Tpt, with shorter holding. For the basic metal (with little deformation), the globular structure disappears practically completely after heating for 10 min at 950°C. In the cold-deformed contact region of the solid-phase diffusion bond, the globular structure disappears on heating for 1 h at 950°C, for 40 min at 975°C, and for 20 min at 1000°C. At those temperatures the sealing of discontinuities is practically complete. In other words, the weld line disappears: the metal with continuous microstructure in the contact region does not differ from the basic metal, except for a slight enlargement of the microstructure. Quantitative assessment of the structural changes in terms of the basic characteristics of the structural interface permits determination of their mechanism and kinetics and also the dependence of the structure on the plastic strain and the heat treatment. On that basis, it is possible to identify conditions such that the discontinuities are eliminated, the boundaries disappear, and the properties of the solid-phase diffusion bond are no worse than those of the basic metal. [ABSTRACT FROM AUTHOR]

The development of small-scale iron production has expanded the output of cast products in Russia. It is often necessary to strengthen the surface of cast-iron components. To that end, special alloys and metallic powders are applied to the working surface. In addition, strengthening by decarburization in the solid state offers a short cut from the ore to the final iron component; it is even more efficient than the familiar path from ore to steel. In the present work, such structural conversion of cast-iron components is considered. Experiments are conducted in two stages: (1) production and preparation of cast-iron blanks from industrial waste; (2) solid-state decarburization of the cast-iron blanks. The initial iron source consists of rolling scale and iron oxide formed in the surface etching of rolled sheet at AO ArcelorMittal Temirtau. Analysis of the microstructure and the change in the mass transfer between the cast-iron plate and the applied layer of oxide powder yields consistent results and indicates that solid-state decarburization of cast iron and finished castiron components is feasible. [ABSTRACT FROM AUTHOR]

Research shows that the controlled cooling of strip coils should not begin in storage but rather during coil transportation to the store or to the next technological operation. That increases the effectiveness of coil cooling, thanks to the greater heat content of the metal or the greater cooling rates. On the basis of the research, proposals are made for controlled cooling of strip coils in existing lines for the transportation of hot coils to stores, with slow-cooling (thermostat) sections and accelerated-cooling sections. Controlled cooling of strip coils is also possible in newly constructed and reconstructed lines that transport coils of hot-rolled strip to the next technological operation, without intermediate storage. [ABSTRACT FROM AUTHOR]

Surfacing with composite coatings strengthened by carbide, boride, and other particles is currently of great interest in materials physics. The performance of the applied layer is primarily determined by the phase composition of the coating. To permit the selection of coatings capable of withstanding extremal operating conditions, including high loads and abrasive wear, their properties and structure must be investigated in detail. In the present work, state-of-the-art techniques in materials physics are used to study the structure, phase composition, and tribological properties of coatings applied to Hardox 450 low-carbon martensitic steel by Fe-C-Cr-Nb-W powder wire and then subjected to electron-beam treatment. The electron-beam parameters are as follows: in the first stage, energy density per pulse ES = 30 J/cm2; pulse length τ = 200 μs; and number of pulses N = 20; in the second stage, ES = 30 J/cm2; τ = 50 μs; and N = 1. These conditions are selected on the basis of calculations of the temperature field formed in the surface layer of the material by a single pulse. It is found that electron-beam treatment of an applied layer of thickness about 5 mm leads to modification of a thin surface layer (about 20 μm), consisting largely of α iron and the carbide NbC; small quantities of the carbides Fe3C and Me6C (Fe3W3C) are also present. This modified surface layer differs from the unmodified coating mainly in terms of the morphology and dimensions of the secondary-phase inclusions. In the modified surface layer, the inclusions are smaller and take the form of thin layers along the grain boundaries. In the unmodified coating, the inclusions are mainly rounded particles, chaotically distributed within the grain. After electron-beam treatment, the wear resistance of the applied layer increases by a factor greater than 70 with respect to Hardox 450 steel, while the frictional coefficient is significantly less (about a third as much). [ABSTRACT FROM AUTHOR]

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya 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.)

This paper summarizes the results of investigations of influence of the thermal cycles, characteristic for arc welding processes, on the structure and mechanical properties of high-strength alloyed steels with yield strength of 590- 785 MPa, as well as on their susceptibility to cold crack formation. The structural transformations in the metal of heat-affected-zone of welded joints were investigated using a quick-response dilatometer, and its mechanical properties and susceptibility to cold crack formation were evaluated according to the results of tests of standard specimens and by the Implant method, respectively. The diagrams of the structural transformations of austenite in the region of metal overheating of heat-affected-zone of a number of high-strength alloyed steels, the dependences of change in their mechanical properties during welding, and also the data, characterizing the susceptibility of high-strength alloyed steels to cold crack formation at different concentrations of diffusion hydrogen in the deposited metal, are presented. 15 Ref., 4 Tables, 4 Figures. [ABSTRACT FROM AUTHOR]

Copyright of Automatic Welding / Avtomatitcheskaia Svarka 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.)

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.)

In this article, for the first time, research of the defective frog wing of the 1/11 mark on the Latvian Railway has been carried out. In the process of which was collected, processed and the analysis of points defects on the Latvian Railway was carried out for eight compartments of the track distance during 2014, 2015 and 2016 (Developed a chief of defectoscopy shop V. Glotov, approved CD the chief of the distance V. Makedon). The frog wing of the 1/11 mark (the 60 E1 DO 04 07 frog type) was considered according to the basic classification of the defects, and an analysis and research of the cause of its fracture were carried out. [ABSTRACT FROM AUTHOR]

The relationships governing the formation of the structure of metals in electron beam welding are investigated by fractal analysis, which determines the single numerical parameter for describing the macrostructures of welded joints in order to evaluate the homogeneity and fragmentation of the structure. The results are then used to determine the relationship of the welding conditions with the fractal dimension of the structure and the properties of the metal of the welded joint, in particular, the long-term strength limit. [ABSTRACT FROM PUBLISHER]

Copyright of China Harbour Engineering is the property of Editorial Office of China Harbour Engineering 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 development of macroscopic inhomogeneities in the form of Chernov-Luders bands and serrated deformation bands (Portevin-Le Chatelier effect) in plastic metal flow is studied. For these two cases, regularities in the development of deformation inhomogeneity were established and the kinetics of motion of the fronts of Chernov-Luders bands and serrated deformation bands was studied. It is shown that the Chernov-Luders fronts and the serrated Portevin-Le Chatelier deformation can be considered as macroscopic autowave switching and excitation processes, respectively, in deformable media of different nature. [ABSTRACT FROM AUTHOR]

The processes of corrosion-fatigue failure of materials in contact with mineral fertilizers are insufficiently studied. As a result of joint influence of atmospheric corrosion and mechanical loads, about 70 to 80% of machine parts get out of order, 20 to 25% of which are failures caused by operating overload due to the strength loss because of atmospheric corrosion. A large part of metal structures of agricultural vehicles used to transport mineral fertilizers is under the direct influence of aggressive environments and dynamic loads that occur during the motion by field roads. Saturated solutions of the most aggressive working environments used in agricultural production, in particular ammonium sulphate and nitrophosphate are investigated to reduce fatigue resistance of ordinary steels groups -- St3 and St5 (GOST 2651:2005; DIN 17100) and quality steels -- 10 Steel, 15 Steel, 20 Steel, 25 Steel (GOST 1050-88; DIN 17200) when loaded at all levels. The fatigue endurance limit decreases in comparison with air up to 2.02 times in a solution of ammonium sulphate, and to 2.32 times in a solution of nitrophosphate. In organic fertilizer environments, compared to distilled water, the conditional fatigue endurance limit increased to 9%. The properties of the given materials as an inhibitor of corrosion-fatigue failure were discovered and proved. [ABSTRACT FROM AUTHOR]

Plastic deformation may occur in metal structure during the manufacturing and service process which will affect the service life of equipment. This study proposes a radio‐frequency method resulting from electromagnetic properties variation for metal plastic deformation monitoring. There is a clearly correlation between the macroscopic electromagnetic properties and the plastic deformation of materials. The energy distribution of radio‐frequency varies obviously due to electromagnetic properties variation according to the simulation results. Meanwhile, the reflection features are mainly affected by permeability and electric conductivity of the material. Experiments have been conducted to verify simulation results. The results of the experiments indicate that the reflected radio‐frequency signal strength decreases with progressive plastic deformation in metal, which has been in conformity with simulations. [ABSTRACT FROM AUTHOR]

The purpose of this paper is, on the one hand, to set the kinematics of the mining extraction system used for the mechanization of well drilling and, on the other hand, o perform calculations to verify the metal structure of the metal tower of extraction system, both by classic analytical calculation as well as by the finite element method. The metal structure of the extraction tower is modeled as a planar frame, which is an unspecified static system loaded with the technological forces that appear in the extraction cable and the mass forces given by the weight of the tower with the Solid Edge utility by 3D modeling. [ABSTRACT FROM AUTHOR]

The state and key directions of development of technologies for restorative heat treatment of steam pipeline welded joints are considered. The technologies of heat treatment and their advantages and disadvantages are presented. The first part of the review presents a summary of the development of restorative heat treatment. The directions of development of restorative heat treatment of welded joints, the most promising for extension of service life of steam pipelines according to the opinion of the authors, were formulated and justified. The justification of the possibility of using heat treatment of long-operating elements of steam pipelines with a degraded structure and presence of damages is given. The possibility of producing a metal of a steam pipeline with a structural state and properties, meeting the service requirements is justified. [ABSTRACT FROM AUTHOR]