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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 of aluminium AMg6 alloy with an increase in their thickness d was carried out. Mathematical modelling of the kinetics and residual stress states of butt-welded joints d = 2, 4 and 8 mm was carried out as a result of their EDT at different values of temperature T of the plates, at which the treatment was performed. The value of the vertical velocity V0 of the electrode-indenter (EDT tool) was taken as V0 = 5 m/s, which corresponds to the modern electrophysical characteristics of the equipment for EDT. The values of T were 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 three-dimensional formulation using the ANSYS softare. The conditions for the formation of stresses in the plates at EDT after and during welding were determined by the mechanical characteristics of AMg6 alloy at temperatures T = 20, 150, and 300 °C without taking cooling into account. The results of the computation of residual stresses in welded joints are presented. It is shown that at a value of T = 150 °C, EDT provides the most optimal residual stress states of the plates in the entire experimental range of d. It was proved that EDT in the welding process (at T = 150 °C) is more efficient compared to EDT of metal after cooling (T = 20 °C). It was established that at EDT of welded joints d = 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 AMg6 alloy. At EDT of welded joints d = 8 mm, residual compressive stresses are formed on the outer surface of the plates, and on the back side -- tensile ones. [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-strain 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 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 a shape of the electrode-indenter on stress-strain state of the welded plate from aluminium 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 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 (of axisymmetric shape) as compared to the roller (of planar elongated shape) is more effective from the standpoint of optimizing the residual stressed state in the plate. the use of a cylindrical indenter leads to the formation of compressive stresses in the plate with the values 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. [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 T = 150 °C, compared to EDT at T = 20 °C. 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 distortion, compared to postweld eDt. [ABSTRACT FROM AUTHOR]

The calculated evaluation of effect of impact interaction of the 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 the 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 a 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]

The effect of thermal action in the process of electrodynamic treatment (EDT) of welded joints of AMg6 alloy on their stressstrain states was investigated. Based on 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 as a result of their interaction with the electrode-indenter at EDT was developed. 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. The 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 compressive stresses in the weld centre as compared to the treatment at T = 20 °C. [ABSTRACT FROM AUTHOR]

The calculated model of the process of impact interaction of the electrode-indenter with the plate of aluminium 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 movement of an elastic-plastic medium in a plane two-dimensional Lagrangian formulation using the software «ANSYS/LS-DYNA». The results of calculating the process of forming areas of residual stresses and plastic deformations under the impact action of the indenter are presented. It was found that under the impact action of the indenter at a speed of 10 m/s on the reverse surface of the plate of AMg6 alloy, the values of plastic deformations are higher than on the contact 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]