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The paper shows the possibility of manufacturing metal flux-cored wires based on high-strength titanium alloys of different compositions (Ti–5Al–5Mo–5V–1Fe–1Cr and Ti–5Al–5Mo–5V–4Nb–1.5Cr–1Fe–2.5Zr systems), alloy based on medical grade titanium (Ti–13Zr–13Nb system) and structural titanium VT6 alloy (Ti–6Al–4V system), reinforced with TiC particles. The technological moments of the experimental production of metal flux-cored wires by the method of drawing and subsequent pulling are shown. The study was conducted on using these materials as a filler metal in WAAM technology both in the methods of argon arc as well as electron beam surfacing. [ABSTRACT FROM AUTHOR]

Within the framework of currently urgent problem of reconstruction and restoration of equipment of thermal power units of TPP, work has been performed on development of basic technology of welding body elements of a steam turbine from low-alloyed 15Kh2M2FBS (P3) steel to branchpipes from high-chromium martensitic X10CrMoVNb91 steel with 9 % Cr (P91). The paper gives the results of determination of the thermal mode of welding such combined joints to prevent delayed fracture. Proceeding from study of the influence of different modes of high-temperature tempering on impact toughness of weld metal and hardness of welded joint areas hardened during welding, heat treatment modes were selected, depending on electrode material type. It is shown that the resultant mechanical properties of welded joints correspond to the requirements specified during work performance. 12 Ref., 5 Tabl., 9 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of studies on production of layered composite materials, based on aluminium and titanium alloys, by vacuum diffusion welding, with a broad range of specific weight values, which is achieved due to different layer ratio in each of the composites. Based on a layered composite material, a procedure was proposed for manufacture of three-layer honeycomb panels by vacuum diffusion welding. It is found that the average compressive strength of the three-layer panel with a filler from a layered composite material based on Al–Ti alloys is equal to 47.3 MPa, that is four times higher that the strength of similar honeycomb elements made from an aluminium alloy. It is shown that the layered material has higher thermal stability, compared to aluminium alloys. Sample annealing at the temperature of 700 °С for 30 min does not lead to their early destruction or loss of shape. [ABSTRACT FROM AUTHOR]

The paper describes the experience of repair welding of service defects in the body of the connecting rod of mobile jaw crusher Metso lokotrack LT 120, which is a rather rigid honeycomb structure from cast low-alloyed steel of 20GL type with thickness of external walls of 60 mm and of partitions of not less than 45 mm and more than 5 t weight. It was found that the most signifi cant defects – fatigue cracks and cleavage which are incompatible with performance, naturally formed near the structural stress raisers, service damage, caused by contact impact of armour protection, casting defects, as well as in the sites of unsmooth connection of elements, etc. Crack opening displacement is equal to 2…3 mm that is indicative of the start of shape change of the body and need for prevention of further operation in such a state. Rigid structure of the connecting rod body and general state of destruction required special technology of repair welding, which was created and realized by the authors. It included new welding materials, technological measures and engineering solutions and those verifi ed by our own practical experience of repair of cast structures, as well as high skill and competence of the welders. Practical importance and eff ectiveness of the performed work on connecting rod repair was confi rmed by safe operation of the crusher in the design mode for two years. 9 Ref., 3 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of determination of the quantity and dimensions of grains of the structural components of steam pipeline welded joint metal. The above determination was performed using an improved method of analysis of the structuralphase state of welded joints. It was found that during long-term operation of welded joints the grains of α-phase increase in size. Structural analysis was performed for base metal of welded joints, HAZ regions, as well as weld metal. It was established that at long-term operation of steam pipeline welded joints grain dimensions are increased in their HAZ regions. It was found that the boundaries between individual grains are partially eliminated. Based on analysis of statistical data, grain dimensions, as well as their shape and distribution were determined at application of the secant method. 9 Ref., 1 Tabl., 7 Fig. [ABSTRACT FROM AUTHOR]

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

The papers presents the mam technical means and methods of pulsed control of the process of consumable electrode gas-shielded arc welding, developed over the recent years at PWI and Admiral Makarov National University of Shipbuilding. A lot of attention is given to methods using systems of pulsed impact on the processes of electrode metal transfer, weld formation and deposited metal structure. Good prospects for application of systems with pulsed dozed feed of electrode wire are shown, and results of effective control of welding and surfacing processes are given. Methods of arc welding with pulsed feed of shielding gas and two-jet gas shielding are considered, and problems are indicated, which prevent extensive application of these processes. The paper gives the results of some studies of the influence of external electromagnetic impact on electrode metal transfer, weld formation and crystallization, and presents some examples of effective application of this method of welding process control. Analysis of the methods of mechanical impact on the weldmg process using different oscillator systems was performed. The possibility is shown of combined control of electrode metal transfer, deposited bead formation and its metal structure, depending on the scheme of oscillation application and oscillation process parameters. The good prospects for this method application for surfacing operations are pointed out. [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]

The paper presents the results of investigation of heat-resistant diffusion coatings on steel 08Kh17T and steel 45, produced by aluminizing and chrome aluminizing methods in powder mixtures at 900...950 °C temperature for 2...5 h. The parametric diagrams of heat resistance were plotted on the kinetic dependencies of oxidation of the samples with coatings in 800...1000 °C temperature interval. They allow evaluating endurance of protective coatings at any temperatures up to 1000 °C. [ABSTRACT FROM AUTHOR]

The use of hy Lukasevich Research Network - Institute of Welding, 16-18 Bl. Czeslava str., Gliwice, 44-100, Poland brid laser-arc welding laser + MAG for joining elements of large structures of stainless steel is a relatively new problem. The paper discusses the issues of technology of hybrid welding of austenitic steel X2CrNil8-9 and austenitic-ferritic steel X2CrNiMoN21-5-1 using a disc laser of 12 kW capacity. The technological conditions of hybrid welding with a full penetration of butt joints of steel with a thickness of 8, 12 and 20 mm, as well as T-joints with a butt weld with a partial penetration were determined. The typical defects in welds of high alloy stainless steels, produced by hybrid welding, were indicated. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the heat resistance of coatings, produced by the methods of plasma (PS) and highspeed flame spraying (HSFS), using composite powder based on FeAlCr with addition of 2 wt.% CeO2, as well as by the methods of arc spraying (AS) and activated arc spraying (AAS) with application of flux-cored wire of the following composition 98(82Fe+16Al+2Cr)+2CeO2 (wt.%). Composite powder was prepared by the method of mechanico-chemical synthesis (MChS) by treating a mixture of powder components in a planetary-type mill. Heat-resistance testing was performed in air at 800, 900 and 1000 °C for 7 hours by weight method. Coating structure after heat-resistance testing was studied with application of metallographic and X-ray structural analysis (RSPhA). It is found that during testing of coatings produced by PS and HSFS methods the delamination phenomenon is observed, whereas coatings produced by AS and AAS methods preserve a tight bond with the base. Obtained kinetic curves of high-temperature resistance showed that in the entire time interval of testing at 800 - 1000 °C the oxidation mechanism follows the parabolic law. The data of kinetic dependencies were used to plot the parametric heat resistance diagrams, allowing evaluation of fatigue life of the studied protective coatings in the temperature range of 800 - 1000 °C. The highest heat resistance is found in FeAlCrCeO2 coatings produced by AS and AAS methods from flux-cored wire. At 1000 °C it exceeds the resistance of steel 45 23-26 times, and corresponds to heat resistance of 08Kh17T steel. 12 Ref., 2 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of modelling of temperature fields, stresses and deformations in formation of additive multi-layer structure of aluminum alloy 1561, low-alloy structural steel of 09G2S grade and titanium alloy of Grade 2 grade. Based on the experimental results obtained earlier at the E.O. Paton Electric Welding Institute during application of additive deposits of these materials the computer modelling was carried out for improvement of technology of additive process. In course of calculations there was analyzed an effect of algorithm of sequence of additive layers deposition, namely deposition of cylinder casing on circle and on spiral, on distribution of temperatures in deposition and its resistance to external loads. It is determined that the spiral deposition technology is reasonable to be used in formation of cylinder casings by additive method and apply less heatconducting structural materials, i.e. structural steels and titanium alloys. [ABSTRACT FROM AUTHOR]

The paper presents the results of high-temperature differential thermal analysis of braze alloys based on Cu-Mn-Ni-Si system, metallographic examination of brazed joints of 08kp (boiling) steel, made with application of plasma-arc heating. It is shown that at silicon alloying of Cu-Mn-Ni system the alloy melting temperature decreases and its wetting ability increases. X-Ray microanalysis revealed that brazed seam of 08kp (boiling) steel joints consists of copper-based solid solution and dispersed precipitates of a silicon-enriched phase. An iron-based phase with higher concentration of silicon and manganese forms on braze alloy - base metal interphase as a thin band (along the brazed seam), that is indicative of appearance of silicides of a complex composition. Brazed joint strength becomes higher with increase of nickel concentration in the alloy and is equal to 367 MPa. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the formation of macrostructure and distribution of mechanical properties in welded joints of flat samples from aluminium alloy EN AW 6082-T6 8 mm thick, produced by the method of friction stir welding with application of three types of specially designed pins with shoulders: C - cylindrical threaded pin and shoulder with a spiral groove; T - cylindrical threaded pin with three grooves and shoulder with a spiral groove; S - smooth cylindrical pin without thread and flat shoulder. Friction stir welding was conduced in the equipment of the Institute of Welding in Gliwice (Poland), and treatment and mechanical testing were conducted at PWI. Mechanical testing by indentation was performed in Microngamma instrument, which allows experimental identification of the structural state of metal after refinement and determination of the presence of strain ageing by limit values of the ratio of hardness to Young’s modulus of elasticity. It is found that for all the three samples HAZ hardness decreases, and in the thermomechanical impact zone hardness increases. Maximum hardness values are inherent to the central part of welded joint nugget, as well as to light-coloured oval concentrated fragments of the structure in the nugget upper and lower part. Judging by the presence of nanosized strengthened structure and uniformity of its distribution in the nugget, as well as good dispersion of oxide films and absence of discontinuities, friction stir welding with C-type tool can be regarded as the optimum variant. An assumption was made that formation of a uniform structure in welds can be achieved at three-four rotations of the tool in friction stir welding in one spot. [ABSTRACT FROM AUTHOR]

The paper shows the favourable effect of nitrogen alloying of high-alloyed corrosion-resistant steels and weld metal on stabilization of the structure, prevention of grain boundary segregation in the HAZ and weld metal, and ensuring high corrosion resistance and technological strength of welded joints. 15 Ref., 2 Tabl., 10 Fig. [ABSTRACT FROM AUTHOR]

The paper considers an approach for selection of filler material in TIG welding of titanium alloy VT22. It is shown that weld metal obtained using pilot flux-cored wire PPT-22 is a representative of transient class of titanium alloys, to which VT22 alloy is referred to (coefficient of β-stabilizing of such metal equals 1). This wire can be used for argon-arc welding of high-strength titanium alloys VT22. Mechanical properties of such welded joints after heat treatment reach the level of base metal indices. Application of PPT-22 wire in restoration argon-arc surfacing of VT22 alloy parts provides their high service characteristics. 15 Ref., 4 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]

The paper deals with the effect of dispersed particles of refractory compounds (Al2O3, MgO, ZrO2) added as cold filler to 1.6 mm flux-cored wire, on modification of the dendritic structure in low-alloyed weld metal of C-Mn-Cr-Ni-Mo-Si-Cu system of K65 strength class. Obtained results do not allow making an unambiguous conclusion on the mechanism of the effect of refractory oxides on dendritic structure modification. 5 Ref., 6 Tabl., 14 Fig. [ABSTRACT FROM AUTHOR]

The paper provides a comparative experimental evaluation of effect of different factors on residual deformations in arc surfacing of thin steel plates. Effect of composition, structure state and part fi xing method in surfacing with Sv-08A, PP-Np-25Kh5FMS and Sv-Kh19N18G6M3V2 wires on plates from St3 steel of 3×150×240 mm size were evaluated at different conditions of their fi xing. It is experimentally determined that differences in physical properties and structural state of base and deposited metal have the highest effect on the level of residual deformations. The results obtained in this work can be used in development of technology of wear-resistant surfacing of thin sheet structures. 9 Ref., 2 Tabl., 4 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the procedure and results of investigation of hot hardness of deposited high-chromium cast irons with different level of alloying of 450Kh30M, 500Kh22B7, 500Kh22B7M7V2F, 300Kh25S3N2G2 type as well as 500Kh40NS2GRTs nickel-carbide-chromium alloy. It is determined that hot hardness of deposited metal to significant extent depends on presence and types of carbides in metal structure. With relatively low-alloy high-chromium cast irons the hardness drops at rise of temperature and increases at chromium content up to 30% and carbon to 5%. Alloys doped with chromium, niobium, molybdenum, tungsten and vanadium keep high hardness up to 650 °C temperature. Niobium is important for indicated alloys. It plays a role of modifier delaying growth of primary chromium carbides and forming solid cubic niobium carbide. Nickelcarbide- chromium alloy preserves high hardness up to 650 °C temperature due to presence of high concentration of higher chromium carbides in a nickel-based matrix. Wear resistance of deposited alloys drops with rise of temperature in accordance with drop of deposited metal hardness. 12 Ref., 3 Tabl., 3 Fig. [ABSTRACT FROM AUTHOR]

It is shown that in submerged-arc surfacing with the impact of constant transverse magnetic field the coefficient of melting of electrode wires of 3-5 mm diameter increases by 25 – 30%. It is experimentally established that at the impact of an alternating field at unchanged level of the transverse component of induction, the effect of increase of the coefficient of melting depends on the frequency of this field. At increase of the field frequency up to 10 – 20 Hz, the increment of the coefficient of melting decreases to zero values. A procedure was developed for determination of the minimum level of transverse component of field induction in the electrode drop zone, at which the drop is detached from the melting electrode tip. It is shown that the effect of lowering of the coefficient of melting at increase of the field frequency is due to reduction of pulse duration. The paper gives the calculated data, allowing determination of optimum values of induction and frequency of the alternating field, at which the coefficient of wire melting at submerged-arc surfacing (welding) is increased. 8 Ref., 4 Fig. [ABSTRACT FROM AUTHOR]

The paper deals with the features of joining titanium alloy PT-3V to steel 08Kh18N10T by diffusion welding with application of an interlayer of ultrafi ne nickel powder, produced by thermal decomposition of nickel formate Ni(COOH)2+2H2O. Comparison of the structures of welded joints of these materials for presence of intermetallic phases in welding without interlayers and with a nickel interlayer at different mode parameters was performed. Application of ultrafi ne nickel powder at temperatures of 965 and 890 °C leads to formation of a continuous layer of solid intermetallics. At the temperature of 790 °C the diffusion zone has a multilayer structure, differing from the microstructure of steel-titanium joint, produced without the nickel interlayer. Mechanical rupture testing of the welded joints showed that suffi cient strength properties are achieved at application of an interlayer of ultrafi ne nickel powder at lower temperature and pressure, preventing intensive growth of intermetallics. The highest values of ultimate strength were achieved at welding temperature of 760 – 790 °C and were equal to 346 MPa on average. 13 Ref., 3 Tabl., 4 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the history of flux-cored wires appearance and their application as remelted material, both in micrometallurgy (surfacing), and in large-scale metallurgy (electroslag remelting and foundry). Features of technological processes with fluxcored wire application in each of the considered areas are shown. At present technologies ensuring improvement of metal quality in foundry are developing the most actively. Prospects for flux-cored wires application in surfacing from the viewpoint of improvement of their production technology and development of new compositions of deposited metal have largely been exhausted. Technologies of surfacing in a current-supplying mould have certain potential for a wider application, particularly in the field of producing composite layers. Electroslag remelting of metal, as in the years of its development, is mainly focused on producing ingots of a large mass and diameter with application of monolithic electrodes of a large cross-section. [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]

The paper presents the results of a examination of structure and properties of the samples produced by laboratory melt of rail metal (in lightly deformed and cast state) obtained by electroslag remelting after flash-butt welding of rails. The examinations showed that microstructure of weld metal and heat-affected zone in both cases differs by homogeneous dense structure. Fracture of the samples took place mainly in the heat-affected zone. Strength of welded joints from metal in cast state is lower, than lightly deformed one, which is apparently caused by coarse grain, size of which can be refined using heat treatment. Rail steel of electroslag remelting in cast and lightly deformed state has a level of mechanical properties made to non-thermostrengthened rails K76 on GOST R 51045 and DSTU 4344 that reveals the perspectives of application of electroslag remelting for manufacture of rails, including rail tongue, applied in cast steel. [ABSTRACT FROM AUTHOR]

A theory of electric contacts assumes an experimentally-verified inverse proportionality of electric transient resistance from applied load. The paper shows that this condition is not fulfilled at small compression forces of different-sized contacts, which take place, in particular, in excitation of electric arc by contact or breakup of thin conductor. Measurements of electric resistance of near-contact area between thin (0.75 mm diameter) conductor and sheet of steels St37 (steel 10) and 1.4301 (08Kh18N10), brass CuZn37 (L63) and aluminum alloy AlMg3 (AMg3) showed that there is an increase of electric resistance due to elastic deformation of contact surface under effect of local loading in rise of forces to specific limits. Under experiment conditions a boundary force made 2-3 daN, depending on mechanical characteristics of metal. Out of these limits a generally accepted functional dependence becomes effective. [ABSTRACT FROM AUTHOR]

The paper describes the approaches to theoretical investigation and mathematical models of physical processes running in the anode layer of high-current (~102 A) electric arcs, burning in inert gas at atmospheric pressure. Numerical studies of anode processes in electric arcs with nonevaporating (water-cooled) anode, as well as in welding arcs (arcs with evaporating anode) were performed. It is shown that anode potential drop in the considered arcs is negative, having an essentially nonuniform distribution in the region of anode attachment of the arc. The latter circumstance largely determines the pattern of electric current flowing and energy transfer between arc plasma and anode (arc contraction on the anode or discharge distributed over anode surface). A procedure of calculation of effective anode drop in electric arcs is proposed, allowing for the above change of anode potential drop along the anode surface. 32 Ref., 1 Tabl., 15 Fig. [ABSTRACT FROM AUTHOR]

The paper deals with the main technological features which should be taken into account during design, manufacturing and mounting of tanks from 9 % Ni steel for liquefied natural gas storage. They include preparation for welding, selection of welding processes and materials, modular assembly of the tank in site, application of ultrasonic peening of welded joints for stress relieving. 8 Ref., 6 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the promising directions and obtained results in the fields of welding and related technologies, pursued in Belarus at SSPA «Powder Metallurgy», including friction stir welding, additive technologies, flame spraying of powder materials and electrospark coating. Comprehensive development of works in the field of additive technologies is achieved by application of equipment, which ensures polymer and metal 3D-printing, production of metal powders and additional compaction operations. Alongside research performance, this equipment is used for product manufacturing. A unit with a system of recording the welding mode parameters was developed for conducting experimental studies and practical application of friction stir welding. Computer modeling programs (Deform, Sysweld, Ansys, etc.) are used during performance of investigations and development of technological processes and tool designs. Tool manufacture is performed in experimental production, in particular by the methods of powder metallurgy and additive technologies. New scientific and practical results were obtained on development of processes and equipment for flame deposition of coatings from powder materials on parts of various functional purposes, using high power jets (up to 125 kW). Investigations were performed and equipment was developed for forming thick-layer (up to 5000 - 7000 μm) electrospark coatings with application of electrode-anode vibration of 22 kHz frequency. 18 Ref., 8 Fig. [ABSTRACT FROM AUTHOR]

The paper deals with development of the technology of high-frequency welding in manufacture of thin-walled spirally-welded pipes by adding activators to the weld zone and pressure application to improve the strength characteristics of welded joint metal. Investigations are based on scientific principles of theoretical fundamentals of welding, materials science and problems of metal strength. A feature of the considered welding technology is the fact that during heating of the edges to be joined by high frequency currents the activators, having lower melting temperatures, go into the liquid state, bind surface contamination and transport it to the surface at pressure application. Edges of the cleaned metal are joined as a result of running of diffusion processes at temperatures close to base metal melting temperatures. Essentially, the process of joining at the final stage proceeds with the weld metal being in the solid phase. Obtained weld width is not greater than 4 - 8 ~m. Weld metal consists of the base metal being welded, enriched in activator elements. Near-weld zone structure is close to that of the base metal. Thin-walled spirally-welded pipes can be produced with a high quality of welded joint at a high welding speed. 21 Ref., 3 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]

The paper provides the results of investigation and engineering developments being a basis for working out a technology and technique of performance of electroslag welding with consumable nozzle of the strengthening elements of construction columns of high-rise building. An experience of application of new apparatuses and special technological fixture in performance of welding operations under assembly conditions was demonstrated. 15 Ref. , 7 Fig. [ABSTRACT FROM AUTHOR]

Pulsed arc welding is characterized with periodically varying arc power and due to its peculiarities allows solving complex technological issues in development of unique structures, rising efficiency of welding processes, deposit corrosion-resistant alloys on steel. Up to the moment there are a great number of producers of welding equipment introducing in their production the ideas of application of pulsed welding. However, data on effect of pulsed arc welding on the welding thermal cycles have odd nature and, therefore, it is difficult to carry out comparison between the thermal cycles typical for stationary and pulsed arc welding. In welding of high-carbon steels there is a problem of reduction of weld metal stirring with a base metal and due to this increase of welded joint cold crack resistance. Successful application of pulsed arc welding for solution of the problems mentioned above provoked a need in the comparative investigations of effect of modes of pulsed arc welding on parameters of the welds, HAZ and welding thermal cycles in comparison with stationary arc welding produced with high-alloy welding consumables. This was the main aim of the investigations, the results of which are given in this paper. Ref. 31, Fig. 8. [ABSTRACT FROM AUTHOR]

It is shown that at the present time the calculation methods, which allow determining induction in the weld pool zone, which is generated by two-rod devices for input of transverse magnetic field during arc welding. However, these methods are extremely difficult to use. In this paper, the calculation methods for determining numerical values of the induction components of a transverse magnetic field in the weld pool were proposed. The methods are based on the use of experimental data on the value of the induction generated by the transverse magnetic field input device in the weld pool zone at different value of rod crosssections of these input devices. The calculation expressions and an algorithm for their use are proposed to determine the magnetic field induction components in the indicated zone. The satisfactory convergence of the calculated data with the experimental ones is shown. The methods are recommended for using in arc surfacing and welding of products of materials which are not ferromagnetics. 8 Ref., 6 Fig. [ABSTRACT FROM AUTHOR]

Paper presents the results of works on restoration of a damaged area of blade of gas turbine engine fan by means of welding-up of a fragment by electron-beam welding method. An endurance limit (σ-1) was determined for fan blades of D-36 engine with 16-65·103 N thrust repaired by this technology. Metallographic examination of the blades with fragment welding-up after fatigue tests was carried out. Perspective directions on increase of the endurance limit of repair fan blades were proposed. 8 Ref., 2 Tabl., 9 Fig. [ABSTRACT FROM AUTHOR]

The paper analyzes the available literature data on the properties of different materials currently used in the means of individual armor protection and the methods for improving their bulletproof and other service properties are evaluated. It is shown that at the present time to create the means of individual armor protection, a variety of materials are used: fabric aramid or polyethylene fibers, metal plates based on steels, titanium, aluminum and their alloys, as well as ceramics based on boron and silicon carbides, etc. The main advantages and disadvantages of these armored materials are shown. On the basis of literary data, it was established that for the 3-5 class of protection, the armored plates of structural alloyed steels were widely used. To minimize the disadvantages inherent in steel armored plates, it is necessary to use bimetallic compositions with alternating hard and soft layers, produced, among others, by welding or surfacing methods. 20 Ref., 4 Tab., 3 Fig. [ABSTRACT FROM AUTHOR]

The structural pseudo-β-titanium alloys found a wide application in aircraft and rocket building. However, while producing welded joints of pseudo-β-alloys applying method of fusion welding, the difficulties arise connected with change in the structure and formation of metastable phases in welded joint. In this paper, using the developed mathematical model of the TIG-welding process, the influence of thermal welding cycle on the weld shape, cooling rate and structure of welded joint metal of the pseudo-β-titanium alloy VT19 was investigated. A number of phases in the weld metal, heat-affected zone and base metal was established, the phase composition and its effect on the mechanical properties of welded joints were predicted. [ABSTRACT FROM AUTHOR]

The work presents the results of development and manufacture of a unique research complex for investigation of fast processes of heat-mass transfer in consumable electrode arc welding. Advantages of the developed complex over the traditionally applied ones using film and video cameras with shadow principle of registration of heat and mass transfer characteristics are shown. Fast processes were studied with application of high-speed video recording with illumination of the arc gap by Cu-Br laser beam, improving visualization of the studied object — the process of melting and transfer of each drop of molten metal under the conditions of intensive light of the electric arc. The paper contains explanatory diagrams, control algorithms, video frames of a separate welding microcycle, examples of oscillogram recording and graphical representations of changes in their quantitative values. 13 Ref., 1 Tabl., 14 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental and computational studies of fatigue resistance of full-scale samples of the pivot assembly and side wall rack sealing assembly of a gondola car of 12-4106-01 model. It is found that their operating life is determined by fatigue resistance of welded joints of structural elements of the assembly. Their fatigue strength is equal from 12.1 MPa (side wall rack sealing assembly) up to 33.6 MPa (pivot assembly). Sections of fatigue cracks initiation, regularities of their propagation and fatigue strength of structures were established. As shown by calculation of the car body stressed state, the fatigue strength values ensure operation for 34.1 and 57.0 years, for the pivot assembly and side wall rack sealing assembly, respectively, before appearance of the fatigue crack. 9 Ref., 2 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

Titanium pseudo-β alloys have high strength reaching 1200-1400 MPa in aged state as well as high fabricability in comparison with alloys with pseudo-α or (α+β) structure. Such advantages of pseudo-β-titanium alloys, typical representative of which is high-alloy VT19, make this class of titanium alloys perspective for application in new equipment and during modernization of existing one. The paper has studied the effect of mode of electron beam welding, modes of pre-heating and local heat treatment as well as furnace annealing on properties of welded joints of pseudo-β-titanium alloy VT19 produced by electron beam welding. Variation of rate of electron beam welding of alloy VT19 does not allow changing relation between α- and β-phases within the significant limits in weld metal and heat affected zone. Electron beam welding in combination with pre-heating allows regulating the relation between α- and β-phases in welded joint metal and reduce content of β-phase in weld metal of alloy VT19 from 91 to 53% as well as rise strength of welded joints from 876 to 937 MPa. [ABSTRACT FROM AUTHOR]

The main difficulty, appearing in solution of the problem of automatic «tracking» of a welded joint line in tandem arc welding, is related with measurement of side deviations from this line of each of electrodes located close to each other in process of welding. Besides, together with side correction of movement of the electrodes, deviating from the welded joint line, there is a need in angular correction of a torch. It would provide “parallelism” between welded joint line and line joining the electrodes. A new solution was proposed to solve the indicated problem based on application of electric-arc methods of measurements and application of recurrent procedures of linear and angular correction of welding torch movement. The results of computer modelling are given in the paper. [ABSTRACT FROM AUTHOR]

The paper presents the results of investigations of the strength of coatings of low-hydrogen electrodes, baked at 200, 300 and 400 °C, depending on the composition of liquid Li, Na and K-glasses, as well as their binary mixtures. Investigation results were interpreted from the viewpoint of evolution of silicon-oxygen structure of liquid glasses under the conditions of changing kind and ratio of cations-modifiers, as well as the level of water content, related to the parameters of electrode heat treatment. Diagnostics of structural-functional self-organization of silicon-oxygen anions (SOA) in the liquid glass composition was performed with application of the data of nuclear magnetic resonance (NMR). NMR29SI spectrum was used. The generalized results were considered in terms of dominance of polycondensation mechanism. A correlation was established between the values of coating strength and ratio of bridge Q4, Q3, Q2 and non-bridge Q1 connectivities in SOA structure. [ABSTRACT FROM AUTHOR]

The paper deals with the possibility of improving the performance of oil storage tanks with V = 50-120 thous. m3 through application of normalized sheet steel 09G2SYuch-U390 and 09KhG2SYUCH-U440 for design rings of tank wall. A relationship between the length of through-thickness fatigue crack in the butt welded joint of the studied steel and number of tank loading cycles was derived experimentally under the conditions of plane deformation at the initial stage of through thickness- crack propagation. Based on the obtained relationship, it was established that after formation of a through-thickness crack in the welded joint of the wall and appearance of oil leakage, there is sufficient time and conditions for its visual detection and taking measures for elimination of the detected defect. The possibility of application of this method to detect the through-thickness crack is proof of the fact that tanks with design rings from the studied steel satisfy the leak-before-creak criterion. [ABSTRACT FROM AUTHOR]

The paper presents the results of metallographic investigation of metal at test surfacing of 110G13L steel samples with high- chromium cast iron shot in current-supplying mould. Possibility of producing sound bimetal joints and features of formation of metal fusion zone at minimum and maximum penetration of base metal are shown. [ABSTRACT FROM AUTHOR]

The high-pressure heaters are the fundamentally necessary links of the second circuit power units of nuclear power plants with light water VVER-type reactors. They represent one-plane or two-plane piped spirals of carbon steel. The paper presents the results of selection and mastering the mechanized welding technology for applying high-pressure heaters in the manufacture and renovation repair. 20 Ref., 2 Fig. [ABSTRACT FROM AUTHOR]

The paper gives the results of studying the influence of the parameters of the process of submerged-arc surfacing of steel with flux-cored wire of PPBrOF10-1 grade and with coated electrodes ANBO-2, providing deposited metal of the composition, corresponding to cast bronze of BrO10F1L grade, on formation of intercrystalline penetrations of bronze into steel. It is shown that formation of intercrystalline penetrations is the most significantly influenced by values of current and deposition rate. Based on metallographic studies, it is found that absence of intercrystalline penetrations of bronze into steel is achieved at limitation of effective heat input of the process of arc surfacing both with flux-cored wire and with coated electrodes to the value of 450 kJ/m. 8 Ref., 2 Tabl., 2 Fig. [ABSTRACT FROM AUTHOR]

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 tendency to cold cracks 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 tendency to cold cracks 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 area of metal overheating of heat-affected-zone of a number of high-strength alloyed steels, the dependence of change of their mechanical properties during welding, and also the data, characterizing the tendency of high-strength alloyed steels to cold cracks formation at different concentrations of diffusion hydrogen in the deposited metal, are presented. 15 Ref., 4 Tab., 4 Fig. [ABSTRACT FROM AUTHOR]

The paper provides a description of producing a resistance heating element from multilayer coatings, which were deposited on a steel base by the method of microplasma spraying. TiO2 in the form of powder with particles of 15–40 μm size was used to deposit narrow resistive paths. A sublayer from Al2O3 with 40 μm particle size was deposited to provide electric insulation from the steel base. Performed testing of resistance heating elements showed their serviceability up to the temperature of 200 °C at specific power of 75 W. Increase of the temperature of resistance element heating in air above 230 °C leads to loss of electrical conductivity. The main possible areas for such resistance heating element application are mechanical engineering, chemical and radioelectronic industry. Performed experiment allowed demonstrating the fundamental possibility of manufacturing resistance heating elements with resistive paths from TiO2 with application of microplasma spraying technology. 18 Ref., 1 Tabl., 5 Ref. [ABSTRACT FROM AUTHOR]

This paper considers the peculiarities of formation of composite alloys based on tungsten carbides in arc surfacing. It is determined that application of spherical granules of tungsten carbides, which are to lower degree subjected to solution in process of surfacing, is the most reasonable in development of electrode material. The optimum content of reinforcing phase in electrode metal was determined which shall vary in 60-70% limits of material mass in volume. Developed were gas-slag-forming and alloying systems and pilot compositions of the electrodes were manufactured. A series of technological peculiarities on providing coating homogeneity, consisting of components different on specific gravity and grain-size composition, as well as its deposition on electrode rod were specified in experimental way. Determined were specifics of surfacing process using developed electrodes, presented are the results of metallographic examinations of deposited metal. Laboratory abrasive wear tests of composite alloys with pilot electrodes showed their high efficiency. 10 Ref., 1 Tabl., 2 Fig. [ABSTRACT FROM AUTHOR]

The paper gives the results of computational research of the influence of light-shade boundaries promoting preheating of joints of sunlit plates to be welded and their intensive cooling on the shaded side during electron beam welding under the conditions simulating open space, on the stress-strain state. A set of numerical procedures and software for computer modeling of the kinetics of temperature fields, stresses and strains in butt fusion welding of plates from aluminium alloy AMg6, allowing for essentially non-uniform external temperature impact were developed for this purpose. The influence of the position of light-shade boundaries relative to the weld on the forming current and residual stressed state of aluminium plates in welding was analyzed. For this purpose the respective problems of nonstationary thermoplasticity were solved by finite element method, based on computational temperature field kinetics, determined allowing for the features of the impact of welding heat source and conditions of external heating and cooling. Performed calculations showed, in particular, that distribution of residual stresses forming in welded joints of plates from aluminium alloy AMg6 at different position of lightshade boundaries, is characterized by maximum stresses, which do not reach the base metal yield limit (170 -- 180 MPa). Such stresses should not essentially lower the mechanical characteristics and performance of welded parts and components, produced in open space conditions. 6 Ref., 3 Fig. [ABSTRACT FROM AUTHOR]

The paper studies the effect of parameters of arc, laser and hybrid laser-arc welding on formation of structure and properties of weld metal and heat affected zone of butt joints from high-strength low alloy steel S460M with yield limit up to 480 MPa. It is shown that increase of rate of gas-shielded arc welding to 50 m/h (13.9 mm/s) allows receiving a quality weld with increased indices of static strength and impact toughness. Laser welding with increased cooling rate provokes reduction of indices of ductility and impact toughness of weld metal that is related with formation of martensite hardening structure of weld metal and heat affect zone of the welded joints revealing at high cooling rate. Application of method of hybrid laser-arc welding of steel S460M allow decreasing cooling rate of weld metal and heat affected zone in comparison with laser welding method. This provides high level of mechanical properties and impact toughness of metal of these zones. 16 Ref. 1 Tabl., 5 Fig. [ABSTRACT FROM AUTHOR]