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A calculated evaluation of the efficiency of electrodynamic treatment (EDT) effect on the stress state of butt-welded joints of plates made of aluminium AMg6 alloy with an increase in their thickness δ was carried out. Mathematical modelling of the kinetics and residual stress states of butt-welded joints δ = 2, 4 and 8 mm as a result of their EDT at different values of the temperature T of the plates, at which the treatment was carried out was performed. The value of the vertical velocity V0 of the indenter electrode (EDT tool) was taken as V0 =5 m/s, which corresponds to the modern electrophysical characteristics of the equipment for EDT. The T value was set, reflecting the conditions of EDT after welding (T = 20°C) and during fusion welding (T = 150 and 300°C). The problem was solved in a threedimensional formulation using the ANSYS program. The conditions for the formation of stresses in the plates at EDT after and during welding were determined by the mechanical characteristics of the AMg6 alloy at temperatures T = 20, 150, and 300°C without taking cooling into account. The results of the calculation of kinetics and residual stresses in welded joints are presented. It is shown that for a value of Т = 150°С, EDT provides the most optimal residual stress states of the plates in the entire experimental range δ. It was proven that EDT in the welding process (at T = 150°С) is more efficient compared to EDT of metal after cooling (T = 20°С). It was established that at EDT of welded joints δ = 2 – 4 mm, residual compressive stresses are formed over the entire thickness of the plates, the values of which are close to the yield strength of the AMg6 alloy. At EDT of welded joints δ = 8 mm, residual compressive stresses are formed on the outer surface of the plates, and on the back side – tensile ones. 11 Ref., 2 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]

A procedure was developed for nondestructive evaluation of residual stresses in welded joints based on application of high-density current pulses and laser speckle-interferometry. Comparison of the results of residual stress measurement in welded joints, obtained by the developed method and by hole-drilling method, was performed. 19 Ref., 10 Fig. [ABSTRACT FROM AUTHOR]

The development of industry stimulates the development of modern approaches to the optimization of welded structures. The use of pulsed electromagnetic fields, plasma currents, electrodynamic forces and their combined effects is a new trend in engineering practice. Treatment with a pulsed electromagnetic field (TPEMF) is a promising direction for optimizing the stress-strain states (SSS) of welded joints (WJ) made of non-ferromagnetic metal materials. Using the method of electron speckle interferometry, the effect of TPEMF on the SSS of samples of circumferential WJ with a thickness of δ = 1.0 mm from aluminium alloy AMg6 was investigated. The kinetics of the action of the force P of the magnetic field pressure on the residual displacements f and SSS of the samples during their TPEMF were investigated. TPEMF of WJ samples was performed without and with the use of an additional screen (δ = 5.0 mm) contributes to the reduction of f values by 2 and 4 times, respectively, and residual SSS by 50 and 80 %. The advantages of using electrodynamic treatment (EDT) of butt 3.0 mm alloy AMg61 (1561) in the TIG welding process are substantiated. It was proved that EDT during TIG contributes to the formation of peak values of residual compressive stresses in the weld zone by 60 % more than EDT during room temperature (Tk). The use of a pulsed barrier discharge (PBD), which generates a low-temperature plasma on the surface of the metal, contributes to the optimization of its structure. An increase in the hardness of HV structural steel 25KhGNMT as a result of its PBD treatment from 420 to 510 units was established. [ABSTRACT FROM AUTHOR]

Combined 3D printing technology including a combination of additive (layer-by-layer) surfacing with electrodynamic treatment of deposited layer was considered. On the basis of mathematical modeling with the use of the Prandtl-Reiss ratio, on the example of aluminium-magnesium AMg6 alloy, the influence of the shape of the indenter for electrodynamic treatment on the distribution of basic parameters and components of the stress-strained state, in particular, the size of the zone of plastic deformations and stresses, depth and width of the contact interaction zone in a metal layer interacting with a roller-indenter moving along the normal to a layer at a speed of 1, 5 and 10 m/s across the thickness of the deposited layer was studied. It was established that the use of a roller with a contact surface, having a shape of a semi-circle, leads to an almost uniform distribution of compression stresses components in the deposited layer, the values of which can reach the yield strength of AMg6 alloy. The results of mathematical modeling give reasons to recommend the use of an electrode in the form of a semicircle (EC) for the development of combined technologies of 3D printing of volumetric metal products, which consist in combination of additive surfacing (WAAM, plasma, microplasma surfacing, etc.) of a volumetric metal product with electrodynamic treatment of each deposited layer. [ABSTRACT FROM AUTHOR]

The paper is devoted to application of the methods of nondestructive testing and visual examination using UAV (drones) for evaluation of damage of the TV tower structure. A methodology is described, which includes application of aerial photography and photogrammetry method to construct a 3D model of the TV tower and localize the damage. 3DF Zephyr software was used to plot a 3D-model, which allowed sizing the defects and classifying them. Conducted examination provided the grounds for elaboration of the recommendations on operative repair and restoration of the TV tower to ensure its safe operation. The presented results confirm the high potential of the combination of the traditional nondestructive testing methods with remote diagnostics based on application of drones and photogrammerty for examination of large-sized structures. [ABSTRACT FROM AUTHOR]

It was found that a combination of the advantages of ultrasonic testing and electron speckle-interferometry in the case of elimination of their disadvantages is the base for development of the method of nondestructive evaluation of residual welding stresses in full-scale structures. A procedure of nondestructive evaluation of the distribution of residual tensile welding stresses in the weld zone of a butt welded joint was developed. It is based on simultaneous application of ultrasonic testing and electron speckle-interferometry and fulfillment of the condition of «area equality» of the epures of balanced compressive and tensile residual stresses. The procedure was proposed for application on samples of single-pass welded joints of sheet constructions from metallic materials with a stable structure. The subject of the study are tensile residual welding stresses in a MIG-welded sample of a butt joint of structurally stable 1561 aluminium alloy. Residual welding stress component a. longitudinal relative to the weld was evaluated in the plate central area. It was found that the discrepancy of the values of residual welding stresses near the center of the welded joint of 1561 aluminium alloy is equal to approximately 0.1a02 for this material, which corresponds to the claimed accuracy of the methods. Based on the investigation results, a range of procedures was proposed for nondestructive evaluation of the residual welding stresses in full-scale welded structures, based on a combination of ultrasonic testing and electron speckle-interferometry. [ABSTRACT FROM AUTHOR]

The technology of producing Ti-TiC modifiers was improved, which reduced the average diameter of its particles by more than 6 times. The use of the proposed processing procedure made it possible to produce a Ti-TiC powder with at least 20 % of TiC in its composition. It was found that for the investigated modes, processing in kerosene is more effective in terms of dispersion than processing in ethanol. The use of the produced powder as a modifier at its content in a deposited metal 25Kh5FMS at the level of 0.01 %, leads to a significant change in the microstructure and its conversion from a columnar into a cellular one. In terms of the possibility to control the structure and properties of the deposited metal, the most promising is the use of modified Ti-TiC powders of H2 and H4 type, which were produced as a result of high-voltage processing of the mixture of corresponding powders in a hydrocarbon fluid using a voluminous-distributed multi-spark discharge mode. This provides a significant effect on the structure of the deposited metal of type 25Kh5FMS, but at the same time does not lead to the formation of microcracks in the deposited metal. 12 Ref., 1 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]

The development of high-tech industries stimulates the growth of requirements to metal structures and a complex of their main and special properties. The use of pulsed electrical discharges, plasma currents, pulsed electromagnetic fields, and their combined effects to improve the mechanical characteristics of metals and alloys is relevant in connection with the need in replacing traditional energy-intensive technologies of structural materials with more advanced ones. The use of pulsed barrier discharge (PBD) in metal treatment, which generates a low-temperature plasma on the surface of the metal being treated, is a new approach to optimize the mechanical properties of metal materials, which is based on electrophysical processes. In the work, strengthening of structural 25KhGNMT steel as a result of the action of PBD on its surface was studied. The treatment of steel by PBD took place in a discharge device at a voltage increment rate of ≈3ꞏ1011V/s. The influence of the duration of PBD treatment on the value of Vickers hardness (HV) of the test samples was studied. The study of the structure of 25KhGNMT steel was carried out by the method of transmission electron microscopy in order to determine its changes as a result of the action of PBD. It was established that HV values after PBD treatment increase from 420 to 500 kg/mm2, which is accompanied by microstructure dispersion, which positively affects the mechanical characteristics of 25KhGNMT steel. [ABSTRACT FROM AUTHOR]

The development of high-tech industries stimulates the growth of requirements for metal of welded structures, a complex of their basic and special properties. The use of pulsed electric currents, plasma currents, pulsed electromagnetic fields and their combined effects to improve the mechanical characteristics of metals and alloys is relevant in connection with the need in replacing traditional energy-intensive technologies of treatment of welded structures with more progressive. The use of a pulsed barrier discharge (PBD) in the metal treatment, which generates low-temperature plasma on the surface of the treated metal is a new approach to optimizing mechanical properties of high-strength steels for welded structures, which is based on electrophysical processes. In the work, strengthening of 25KhGNMT steel as a result of PBD action on its surface was investigated. PBD treatment of steel took place in a discharge device at an increment rate of voltage ≈3·1011 V/s. The effect of PBD treatment period on Vickers hardness value (HV) of test specimens was investigated. Studies of the structure of 25KhGNMT steel were carried out by the method of transmission electron microscopy to reveal its changes as a result of PBD action. It was found that values of HV after PBD treatment increase from 420 to 505 kg/mm², accompanied by a general increase in dislocation density and dispersion of microstructure, which can positively affect the mechanical characteristics of 25KhGNMT steel for welded structures operating under dynamic loads. 13 Ref., 2 Tabl., 7 Fig. [ABSTRACT FROM AUTHOR]

The advantages of using electrodynamic treatment (EDT) of metal in the welding process as compared to EDT at room temperature were substantiated. The advantages and disadvantages of using electrode for EDT in the form of a cylindrical rod and a roller in the welding process were considered. Using the method of mathematical modeling in planar and axisymmetric statements, the effect of the shape of the electrode-indenter on stress-strain state of the welded plate from aluminum AMg6 alloy after applying the dynamic EDT component was evaluated. The features and differences of creation and use of developed mathematical models were described. The distribution of the values of the stress-strain state throughout the thickness of the plate was determined, in particular, the values of the zone of plastic deformations and stresses during interaction of the plate with the electrode-indenter moving at a speed of 5 m/s. It was found that the use of a cylindrical indenter with a hemispherical working end (axisymmetric shape) as compared to the roller (plane elongated shape) is more effective from the standpoint of optimizing the residual stress state in the plate. The use of a cylindrical indenter leads to the formation of compressive stresses in the plate with the values of up to -120 MPa. This should have a positive effect on the distribution of residual welding stresses under the action of the dynamic EDT component. 4 Ref., 3 Tabl., 7 Fig. [ABSTRACT FROM AUTHOR]

Application of electrodynamic treatment (EDT), taking into account the welding process peculiarities, is a new trend in engineering practice, enhancing the process capabilities. At the same time, a necessary condition for realization of fusion welding process, is heating of the weld metal with its further cooling to room temperature. Realization of EDT technology during welding promotes more intensive relaxation of welding stresses as a result of EDT, compared to weld metal treatment at room temperature. Proceeding from investigation results it was found that EDT of butt welded joint samples leads to transition of residual tensile welding stresses into compressive stresses. Experimental verification of the residual stress-strain state with application of the method of electron speckle interferometry confirmed the results of mathematical modeling, namely lowering of tensile stresses and increase of compressive stresses in the weld after EDT at temperature Т = 150 °С, compared to EDT at Т = 20 °С. It was proved that EDT of samples of butt joints from AMg6 alloy during TIG welding improves their production accuracy that is characterized by lowering of the level of their residual longitudinal grooving, compared to postweld EDT. 14 Ref., 2 Tabl., 6 Fig. [ABSTRACT FROM AUTHOR]

The calculation evaluation of effect of impact interaction of electrode-indenter with a welded plate of AMg61 alloy at its electrodynamic treatment (EDT) in the conditions of elevated temperatures was carried out. The solution of the problem was carried out in a flat two-dimensional Lagrangian statement based on a previously developed mathematical model using ANSYS/ LS-DYNA software. The thermal cycle of welding was set by mechanical characteristics of AMg61 alloy at temperatures of 150 and 300 °C. The results of the calculation of residual stresses during impact action of electrode-indenter at room and elevated temperatures in preliminary tensioned plates of AMg61 alloy of 3 mm thickness were presented. It is shown that the most acceptable temperature (from the studied temperature values) for the electrodynamic treatment of AMg61 alloy is 150 °C. Based on the results of the studies, it was found that the electrodynamic treatment of welded joint specimen in the form of a plate preliminary loaded with elastic tension leads to the transition of residual welding tensile stresses into compression stresses. [ABSTRACT FROM AUTHOR]

A procedure was developed to detect defective areas in aircraft structure elements by electron shearography method. Nondestructive testing of the quality of full-scale elements of SC «Antonov» aircraft structures was performed: parts of helicopter blade and AN-74 aircraft elevator trimmer. Ref. 14, Fig. 8. [ABSTRACT FROM AUTHOR]

High-strength alloy steels of 30KhGSN2A type are widely used in the manufacture of products that can bear significant loads. In the thermally hardened state, this steel has a tensile strength of more than 1500 MPa. Depending on the product, it can be used in thicknesses from 2 to 15 mm and more. However, the use of such steels requires strict technical requirements for their heat treatment, creating difficulties during the manufacture of products. Development of welding technology in the manufacture of products of 30KhGSN2A steel is currently relevant. In the present work, technological features of welding of high-strength alloy steels of 30KhGSN2A type are stated. [ABSTRACT FROM AUTHOR]

The effect of thermal action in the process of electrodynamic treatment (EDT) of welded joints of AMg6 alloy on their stressstrained states was investigated. Based on the of the Prandtl-Reuss ratio for the movement of elastic-plastic environment at elevated temperatures, a mathematical model of evaluation of stress state of metal materials was developed as a result of their interaction with the electrode-identer at EDT. On the basis of the developed model, a calculated evaluation of the effect of elevated temperatures on residual stresses of a preliminary strained plate of AMg6 alloy as a result of EDT was carried out. The verification of the results of the calculation with the use of welded plates of AMg6 alloy of 2 mm thickness was carried out. Thermal action was carried out with the help of the accompanying EDT preheating of the weld metal. To evaluate the effect of the thermal potential of EDT on residual stresses, TIG welding of butt-joint specimens was performed. EDT of specimens at the temperature TEDT = 20 and 100 °C was performed. Applying the method of electron speckle-interferometry, the values of the longitudinal component (along the longitudinal axis of the weld) of residual welding stresses in the central cross-section of the specimens before and after EDT were measured. Thermal impact on EDT was provided with the use of a heat gun, and the heating temperature was controlled by an infrared thermometer. It was revealed that heating of the weld in the process of its EDT along the longitudinal axis of a butt joint provides greater values of residual compression stresses in the centre of the weld as compared to the treatment at T = 20 °C. [ABSTRACT FROM AUTHOR]

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.)

Welding and other related technologies are used in manufacture of space vehicles. When developing the designs of third generation rockets, special attention is paid to problems of improvement of flight reliability and safety characteristics that is ensured by rational application of new types of high-performance welded joints in the design, which are produced due to introduction of effective welding processes. Fabrication of the traditional (waffle) structure and advanced (stringer) structure was analyzed, taking into account the cost-effectiveness of application of the welding processes. In terms of cost-effectiveness, it is rational to apply friction stir welding. Here, a considerable economic effect of application of friction stir welding technology for fabrication of structures of fuel tanks of rocket carriers is anticipated. [ABSTRACT FROM AUTHOR]

The use of the modern method of non-destructive quality testing -- electron shearography in combination with vacuum load for the study of elements of titanium honeycomb panels is considered. The effectiveness of the procedure for detecting inner defects of different location in the honeycomb panels, size and configuration is shown. 10 Ref., 9 Fig. [ABSTRACT FROM AUTHOR]

The problem of selection of testing methods for assessment of the technical condition of the main longitudinal beams of the E.O. Paton Bridge was considered. Special features of the object of control and examination results are briefly described. A qualitative algorithm is proposed for examination of large-sized building metal structures. 7 Ref., 10 Fig. [ABSTRACT FROM AUTHOR]

The calculated model of the process of impact interaction of the indenter-electrode with the plate of aluminum AMg6 alloy during electrodynamic treatment is presented. The solution of the problem is carried out on the basis of the Prantle-Reiss relations for the motion of an elastic-plastic medium in a plane two-dimensional Lagrangian formulation using the program «ANSYS/LS-DYNA». The results of the calculation of the process of forming areas of residual stresses and plastic deformations under the impact of the indenter are presented. It was found that under the impact of the indenter at a speed of 10 m/s on the back surface of the plate of AMg6 alloy, the values of plastic deformations are higher than on the back one. This is explained by the effect of reflection of a plastically deformed layer of metal from the back side of the plate, which stays in the conditions of resting on a rigid support. An experimental verification of the model adequacy during evaluation of the distribution of plastic deformations after electrodynamic treatment of a welded plate of AMg6 alloy was performed. [ABSTRACT FROM AUTHOR]

The results of studying the influence of the modifier of the Al – Ti – C system, obtained by high-voltage electric discharge treatment in a hydrocarbon liquid, on the structure and properties of the cast AK7pch (A357) alloy are presented. The prospects for the use of a modifier produced by the method of a high-voltage electric discharge treatment of metal powders to improve the structure of cast alloys and weld metal are shown. 25 Ref., 1 Tabl., 4 Fig. [ABSTRACT FROM AUTHOR]

The increased number of ruptures in reinforcing ropes after short-time functioning may be associated with their manufacturing and operating conditions. The objective is to establish the main causes of premature breakage of high-strength reinforcement bars, based on the elemental and structural-phase composition of steel, mechanical properties of the wires, as well as the nature of the damaged surfaces and fracture characteristics. 18 Ref., 6 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics 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.)

At present a growing interest in pulsed electromagnetic field treatment technologies is observed to improve the mechanical properties of metals, alloys and welded joints. Based on the pulsed electromagnetic field treatment, effective methods can be developed to optimize the stress‑strain state of aluminum alloy products in order to extend their life for the use in aircraft, shipbuilding and other industries. The aim of the work is to study the influence of pulsed electromagnetic field treatment on the stress‑strain state of circumferential welded joints of aluminum AMg6 alloy. An original experimental procedure was developed to study the kinetics of the electrodynamic pressure force during treatment of metallic materials with a pulsed electromagnetic field. It is shown that as a result of treatment with a pulsed electromagnetic field in the same conditions, the value of P increased with the use of the screen, which is predetermined by the increase in the active additional volume of the electric conductive medium. It was established that the use of the screen during treatment by a pulsed electromagnetic field helps to reduce the level of residual tensile welding stresses and improve the accuracy of circumferential welded joints. 8 Ref., 3 Tabl., 8 Fig [ABSTRACT FROM AUTHOR]

Welded joints of intermetallic β-stabilized alloy of TiAl system – Ti–44Al–5Nb–3Cr–1.5Zr (at. %) were investigated. Intermetallic blanks of 3 and 10 mm thickness were welded by electron beam welding. In order to prevent the occurrence of cold cracks in the welded joints of titanium aluminide samples of different thickness, the following post-welding local heat treatment using an electron beam was performed. This method of processing is one of the most attractive for improving the structure of the ingot and reducing the level of residual welding stresses, which, in its turn, significantly increases the mechanical properties of the alloy. Static tensile tests were performed to assess the strength of welded joints. The samples failed in the base material. The paper presents histograms showing the values of tensile strength (σt) of welded joints obtained during tensile test for samples of different thickness with and without LHT application. It is shown that the use of local heat treatment increases the tensile strength of samples of 3 and 10 mm thickness by 1.8 times, compared with samples produced without LHT. In addition, the values of this characteristic for welded joints of different thicknesses, which are obtained using this technique, are quite uniform. Comparative analysis of the results of tensile tests and the results of microhardness studies was performed, which showed that destruction of the samples took place in the zone of lowering of mechanical properties. The nature of fractures of different parts of the welded joint was studied, which confirmed that fracture occurs in the zone of brittle part of the sample. It is known that mechanical properties of the welded joint are closely related to its structural state. During local heat treatment, an additional β0 (B2) phase appears in the structure, which increases the ductility of the weld material. [ABSTRACT FROM AUTHOR]

The paper considers the possibility for applying automatic orbital welding using non-consumable electrode in helium environment or plasma welding using the methods of autopressing or successive penetration to produce welded joints of pipe elements of highpressure spirals in high-pressure heaters. The results of testing this technology and the optimal modes of producing stationary welded joints of pipe elements in spirals of high-pressure heaters of NPP power units are presented. A description of technical proposals on creation of domestic welding equipment for implementation of the proposed technology was presented. It is shown that the use of the developed technology applying domestic equipment can significantly increase the labour efficiency when producing welded joints of pipe elements in spirals of high-pressure heaters and significantly improve their quality. [ABSTRACT FROM AUTHOR]

The effect of electrodynamic action on the life of welded joints of AMg6 aluminum alloy under cyclic loading was investigated. It was found that electrodynamic treatment of specimens of butt welded joints of AMg6 alloy results in reduction in residual tensile welding stresses, which is followed by their transition to compression. It is shown that as a result of double-sided singlechannel electrodynamic surface treatment in welded joints of AMg6 alloy, the cyclic life is three times increased as compared to the initial one. Additional electrodynamic treatment of the fusion line increases the life by five times as compared to the non-treated metal. In the comparative evaluation of single- and two-channel electrodynamic treatment of samples, it was found that the increase in life when using a two-channel scheme (as compared to single-channel) is determined by the controlled synchronization of components of electrodynamic effect, which eliminates the passage of electric current pulse through its treated metal in the phase of its attenuation. It was shown that the life of two-channel treated specimens with electric pulsed action is more than 50% higher than that of the dynamic ones, which is connected with the contribution of electroplastic effect to the reduction of residual welding stresses. [ABSTRACT FROM AUTHOR]

Intermetallic β-stabilized alloy of TiAl−Ti–44Al–5Nb–3Cr–1.5Zr (at. %) system, which was obtained by electron beam melting was investigated. The cast alloy blanks were re-remelted by the method of induction crucibleless zone melting. This processing method is one of the most attractive for improving the structure of the ingot, which, in its turn, significantly improves the mechanical properties of the alloy. The paper describes the equipment for high-temperature mechanical testing of the alloy. Such mechanical characteristics as yield strength, tensile strength, degree of deformation during compression, as well as the modulus of elasticity and creep rate in the initial state and after ICZM were determined. Deformation curves were plotted from these data. The test results showed that ICZM led to a significant improvement of the high-temperature characteristics of Ti–44Al–5Nb–3Cr–1.5Zr alloy. Ref. 15, Tabl. 1, Fig. 5. [ABSTRACT FROM AUTHOR]

Accidents occurring on railway track of 1520 nun are often associated with the fracture of cast load-carrying elements of three-element freight car trucks. The level of quality and endurance of such truck elements as side frame and truck bolster, which are traditionally manufactured by casting technology, are insufficient, so it is advisable to use welding technology to manufacture the mentioned parts of sheet rolled metal in order to increase the fatigue resistance characteristics. The development of a new all-welded structure of side frame of a three-element freight car truck with an axial load of 23.5 tc was carried out on the basis of widespread use of mathematical modelling to determine the stress-strain state of welded elements of the truck under the action of a regulated range of loads and to evaluate the strength according to the valid standards and modem global approaches. The technology of assembly and welding, as well as the appropriate specialized equipment for manufacture of a developed design of welded side frame were created. Two test specimens were manufactured and accelerated fatigue tests were carried out. the results of which showed a significant increase in endurance and vitality under operational cyclic loads as compared to designs of existing cast side frames. Taking into account high values of reliability, availability and manufacturability, ability of a significant reduction in unsprung weight and increase in dimensional accuracy, the welded structure of the side frame of a three-element freight car truck is very promising for its implementation on railway track of 1520 mm. [ABSTRACT FROM AUTHOR]

To the accuracy and reliability of actuating mechanisms of modern automatic machines for orbital (GTAW) welding of stationary butts of pipelines of NPP power units a number of specific requirements is specified. In particular, they concern the largest diameters of faceplates of welding heads of such automatic machines, in which, as a rule, all or the most of those mechanisms are located. This paper describes the designs of actuating mechanisms of modern automatic machines for GTAW of stationary butts of NPP pipelines, designed at the Scientific and engineering centre of welding and control in the field of nuclear energy. The mechanisms of clamping (fixation) of welding heads on the pipe being welded, the mechanism for stabilizing the arc length, the mechanism for rotation (rotator) of the faceplate around the axis of the pipes to be welded, the mechanism for automatic regulation of arc voltage, the mechanism for oscillation of non-consumable electrode (across the weld) and the mechanism of filler wire feed were developed. The results of industrial operation of some automatic machines for GTAW, designed at the Scientific and engineering centre of welding and control in the field of nuclear energy, are presented, in which the described mechanisms are used. The aim of this work is to present the results of works carried out at the Scientific and engineering centre of welding and control in the field of nuclear energy in the direction of creating components of automatic machines for GTAW of stationary butts of thin-walled pipelines of steels from austenitic, pearlite classes, carbon steels and alloys of non-ferrous metals (except aluminum and its alloys). [ABSTRACT FROM AUTHOR]

In the work, stress state of welded joints of intermetallic of the TiAL system was investigated. The influence of stress state of the weld on cold cracks formation was determined. A mathematical model was created and computational experiments were carried out to determine residual welding stresses in welded joint. Using the methods of optical and electron microscopy, the structure of welded joints of intermetallic of titanium-aluminum system was studied. At the same time, the relationship between the cooling rate of the material after the end of welding process and the structure of welded joint was established. Based on the results of numerical experiments and metallographic examinations, a technology for welding of intermetallic alloy with a subsequent local heat treatment was developed, which allows producing defect-free welded joints. [ABSTRACT FROM AUTHOR]

Development and introduction of new energy-saving technologies meets the modern demands of Ukraine. In the paper background, current state and directions of development of studying the influence of electromagnetic fields on mechanical properties and the stressed state of metal materials and welded joints are considered. The possibility of their application for control of the stressed state, the evolution of structure, properties, elongation of the life of welded structures is shown. [ABSTRACT FROM AUTHOR]

The influence of the parameters determining different duration of electrodynamic effect on reduction of the level of residual stresses in the welds of butt joints of the aluminum AMg6 alloy as a result of electrodynamic treatment was investigated. It is shown that an increase in the duration of electrodynamic effect, achieved by growing in the inductance of the discharge circuit at constant amplitude values of a pulsed electric current, is characterized by a greater increase in the period of current decay as compared to the period of its increment. At the same time, the increase in the duration of electrodynamic effect leads to an increase in the efficiency of the method for reducing the level of residual stresses in the welded joints of the AMg6 alloy. It is noted that at a duration t ≥ 0.7 ms, the decrease in stresses is determined by the intensity of electrodynamic effect and the Joule heating of the plate surface. 5 Ref., 1 Tabl., 4 Fig. [ABSTRACT FROM AUTHOR]

The carried out investigations and practice established that the quality of welded joints of pipelines, meeting the modern requirements largely depends on the quality of treatment of ends of groove edges of their butt joints prior to welding and on the quality of assembly of pipeline components directly before welding. The paper presents the results of experimental, technological and design works carried out at the Scientific and Engineering Center of Welding and Control in the Field of Nuclear Energy, on creating a facing tool for metal pipes of a diameter from 76 to 108 mm. It is shown that, in comparison with the best foreign analogues, the designed facing tool has a number of significant technological and operational advantages. [ABSTRACT FROM AUTHOR]

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 rational methods of construction of metal transformable shells with the aim of creation of the space-purpose structures were investigated. The mathematical modeling of the neutral shell surface of the transformable-volume structure (TVS) was performed, the result of which was used to set the reference surface at the kinematic modeling of its stress-strain states during a compact folding. The parameters of the process of welding thin shells of stainless steel were determined, guaranteeing the maximum approaching of physico-mechanical properties of welded joints to similar properties of the base metal, thus providing their vacuum density. The methods of modification of surface of thin metal shells of stainless steel, which allow improving the safety margin of TVS of space purpose without changing their mass and compactness were developed. The possibility was experimentally confirmed and the conditions of stability of complete reverse transformation of a multisectional conical-type TVS were formulated. 7 Ref., 12 Fig. [ABSTRACT FROM AUTHOR]

The article presents the results of development of technical means of semi-virtual type for training welders and welding production specialists at the SE Scientific and engineering center of welding and control in the field of nuclear energy in cooperation with the E.O. Paton Electric Welding Institute of the NAS of Ukraine and the G.E. Pukhov IPME of the NAS of Ukraine. The level of development of technical means for training and certification of welders and welding production specialists was considered, which allows predicting the expansion in the fields of application of modern information technologies, including those reproducing the mixed reality with the maximum adaptation of virtual space to real welding equipment and providing the remote access of telecommunication systems. It was shown that simplification of training and its approximation to the conditions of real welding processes is possible using a new generation of welding simulators, in which modern information technologies are widely applied. [ABSTRACT FROM AUTHOR]

Some theoretical problems of resistometric method for determination of welding arc spot coordinates and evaluation of speed of electrode movement during realization or simulation of arc welding, as well as the peculiarity of creating hardware part and software of simulating welding systems are considered using this method. The examples of using this method in the hardware-software complexes (welding simulators), as well as the basic variants of circuit design of devices for realization of resistometric method in the simulating welding systems, designed and industrially manufactured at the SE «Scientific and engineering center of welding and control in the field of nuclear energy of Ukraine of the E.O. Paton Electric Welding Institute of the NAS of Ukraine, are presented. 17 Ref., 4 Fig. [ABSTRACT FROM AUTHOR]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics 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.)