The process of forming welded joints by high-voltage capacitor welding

The article substantiates the relevance of obtaining welded joints from dissimilar alloys with minimizing the processes responsible for the formation of intermetallic joints by using high-voltage capacitor welding with an induction-dynamic drive. A schematic diagram of high-voltage capacitor welding is given, the physical nature of the work is described. The parts to be welded are connected in series to an electric circuit and an inductor, which is a feature of this method. The physical processes and stages of high-voltage capacitor welding with an induction-dynamic drive are described. Comparison and analysis of high-speed photographic recording with oscillograms of current and voltage is carried out. The presence of an inductive resistance in the discharge circuit shifts the discharge current relative to the voltage. Confirmation of the hypothesis of formation of welded joints in the solid phase is based on the analysis of welded joints by scanning electron microscopy. Energy dispersive analysis of the welded joint zone did not reveal the diffusion of zinc into the AlMg2.5 alloy and magnesium into the B63 alloy. Energy dispersive analysis confirmed the assumption about the formation of a welded joint under conditions of wetting of molten metal by a pulsed electric arc, followed by displacement from the joint zone and plastic deformation of the heated metal. Recommendations are given for taking into account the polarity in high-voltage capacitor welding, depending on the thickness of the thinnest element.

FEATURES OF FORMING THE VT1-0+AMG5 JOINT DURING EXPLOSION WELDING WITH THE INFLUENCE OF ACOUSTIC VIBRATIONS

The work is devoted to the study of the influence of the introduction of acoustic vibrations during explosion welding of the VT1-0 + AMg5 pair. A comparative study of joints obtained by the conventional method of explosion welding and explosion welding with the effect of acoustic vibrations in various welding modes has been carried out. The results of the study of the microstructure and mechanical properties allow us to speak about the positive effect of the introduction of acoustic vibrations during welding VT1-0 + AMg5, which consists in expanding the weldability area and reducing the volume of the melted metal in the joint zone. It is also shown in the work that the nature of surface preparation before welding can have a significant effect on the strength of the joint.

COMPARATIVE ANALYSIS OF SPATIAL STRESS IN THE JOINT ZONE OF TOWER PIER UNDER DIFFERENT SYSTEMS OF CABLE-STAYED BRIDGE

To explore the stress of the tower-beam-pier joint zone of a cable-stayed bridge under different systems, the submodel method in the finite element software ABAQUS was used to establish the local model of the tower-beam-pier joint zone of the bridge. At the same time, Midas/Civil was used to establish the rod system finite element model of the whole bridge. The correctness of the local model was verified by comparing the results of the finite element model and the local model. Then, by changing the combination mode of tower beam pier, the stress comparison analysis of the joint zone of the tower-beam-pier under different systems was carried out. The results showed the stress distribution of the semi-floating system was more reasonable than that of the rigid frame system and the consolidation system. In the use of the three different systems, there was concentrated tensile stress at the chamfer of the web and the bottom plate, where the steel bars should be added. In the rigid frame system, the deflection of the main beam under the load was the smallest, and the maximum displacement occurred at the boundary section, with the value of only 2.668mm.

X-RAY STUDIES OF COMPOSITE MATERIAL STEEL 20 - STAINLESS STEEL 50CR15MO2V AFTER EXPLOSION WELDING AND NORMALIZATION

The results of studies of the characteristics of the fine structure of a bimetal made of stainless steel 50Kh15M2F and carbon steel 20 after explosion welding and subsequent heat treatment in the joint zone are presented. It was found that normalization at temperatures above 900 ° C leads to a martensitic transformation in steel 50Cr15Мo2V, which is accompanied by an increase in hardness and the development of a fine structure: an increase in the level of elastic deformation of the crystal lattice and fragmentation of coherent scattering regions.

ASSESSMENT OF THE OIL AND GAS POTENTIAL PROSPECTS OF THE NEOKOMIAN SEDIMENTS IN THE JOINT ZONE OF THE GYDAN, YAMAL AND NADYM-PURPEY OIL AND GAS BEARING REGIONS OF WESTERN SIBERIA ON THE BASIS OF 3D SEISMIC SURVEY

The article presents a brief overview of the views on the stratification of the section of the neocomian deposits. As a basis for geological modeling, instead of formation units, seismic facies complexes were taken, including reservoirs in the coastal shallow-water zone, in a relatively deep-water zone - isochronous clinoform formations of the achimov strata. Within the researched territory, the characteristic of the established oil and gas potential of the complex is presented, on the basis of 3D seismic survey, perspective objects are identified, and their seismogeological characteristics are given.

INFLUENCE OF HIGH-VELOCITY IMPACT PARAMETERS ON THE STRUCTURE AND PROPERTIES OF THE VT1-0 + AMG5 JOINT

The paper presents the results of studying the joints of VT1-0 titanium with the aluminum-magnesium alloy AMg5, obtained by explosion welding in different modes of impact. The analysis of microstructures showed that, depending on the conditions of collision, the boundary of the joint zone can have both a wave and a waveless profile. Areas of melted metal are formed even with minimal energy input, but until a certain point they do not significantly affect the strength of the joint. At relatively low values of the energy W, titanium weakly dissolves in aluminum and is present in the melted areas in the form of crushed particles. A further increase in the modes of explosion welding leads to an increase in the degree of dissolution of titanium in melts, which is accompanied by the appearance of cracks. The results of the performed mechanical tests showed that the values of the peel strength of the layers are noticeably higher and reach an equal-strength joint in comparison with the method of welding through an intermediate layer of pure aluminum. In the investigated range of welding modes, the strength of the joint increases in the energy range W = 0,85...1,1 MJ/m, and at W = 1,1 MJ/m it reaches a maximum. With a further increase in the modes of explosion welding, the strength of the joint decreases, which is associated with a change in the structure of the melted regions with the formation of brittle intermetallics in them.

STRUCTURE TRANSFORMATION IN THE ZONE OF BIMETAL COPPER + STEEL 30CRMNSIA AFTER EXPLOSION WELDING AND FOLLOWING ANNEALING

The results of studies of the structure in the joint zone of 30CrMnSiA steel with copper М3 after explosion welding and subsequent annealing at a temperature of 880 ° C and a holding time of 1 hour are presented. The formation of alloys of various configurations is shown, the distribution of chemical elements and the distribution of hardness over the cross-section of the bimetal are studied.

The Effect of Top Surface Lubrication on the Friction Stir Welding of Polycarbonate Sheets

In this work, top surface lubrication during friction stir welding of polycarbonate sheets was applied. A homogenous layer of Paraffin wax has been placed on the top surface of the joint area with a width that ensures to cover the shoulder diameter. Then FSW was applied using conventional FSW tool with rotating pin and shoulder at different FSW parameters (Rotation speeds of 1 000, 1500, 2 000 min–1 and welding speeds of 25, 50, 75,100 mm/min). The main objective of using the wax is to act as a lubricant that reduces the friction between the shoulder and the polycarbonate surface. The joints produced were investigated in terms of surface quality, internal defects, and mechanical properties. During FSW the wax is melted and played as lubricant between the tool shoulder and the polycarbonate surface and resulted in defect-free surface with no thickness reduction of the original plate. The transverse cross-section showed defect-free joints for the majority of the FSW parameters investigated. Tensile testing results showed a reduction of the tensile strength after FSW, and an enhancement in the tensile strength with the increase of welding speed or rotation speed. The fracture occurs at the joint zone and the fracture surface investigation using SEM showed the existence of spherulitic structure in the weld joint.

FEATURES OF STRUCTURE FORMATION IN EXPLOSION WELDED BIMETAL STEEL 20 + STAINLESS STEEL 50CR15MO2V AFTER LONG HIGH-TEMPERATURE HEATING

The results of studies of the structure in the joint zone of stainless steel 50Cr15Мo2V with carbon steel 20 after explosion welding and subsequent heat treatment at a temperature of 1000 ° C and holding times of 5-20 hours are presented. The formation of a continuous diffusion layer in the joint zone is shown, the thickness of which depends on the holding time.

Achievements of the department for development of new products, related technologies and materials of JSC RosNITI

The latest achievements of the department for new products, related technologies and materials are presented in the following areas: creation of anti-corrosion and conservation coatings; development of cylinders; development and testing of rolling tools, technological lubricants and coatings. Based on the results of the activities of the department employees, high-tech science-intensive types of new products with high added value, which are in demand in the market, have been developed and implemented, such as heat-insulated lift pipes, oil and gas pipes with a metal coating of the welded joint zone, pipes with threaded casing connections with GW coatings, pipes with deoxidized inner and outer surfaces, cylinders of new designs, original lubricants and deoxidizing materials.