Promising methods for regulating the stress-strain state of welded joints

The development of industry stimulates the advancement of modern approaches for optimizing welded structures. This study presents three technologies for the treatment of welded structures based on the use of pulsed electromagnetic fields, plasma currents, electrodynamic forces, and their combined effects—an emerging direction in engineering practice aimed at improving the mechanical properties of metallic materials and welded joints. Treatment with a pulsed electromagnetic field（Tw PEMF） technology is introduced, which enables the optimization of the stress-strain state in welded structures made of non-ferromagnetic materials. The study investigates the stress-strain state of ring-shaped samples of welded joints made from AMg6 aluminum alloy（δ = 1.0 mm）, using electronic speckle interferometry, both with and without an additional conductive shield, after Tw PEMF. It was found that Tw PEMF reduces the displacement values by 2 and 4 times and decreases residual stresses by 50 % and 80 %, respectively, in samples without and with the shield. Also presented is an electrodynamic treatment（EDT） technology for butt-welded joints of AMg61（1561） aluminum alloy with a thickness of δ = 3.0 mm during tungsten inert gas（TIG） welding, compared to EDT applied at room temperature. Based on mathematical modeling and experimental data, EDT during TIG welding contributes to the formation of an optimal residual stress-strain state of the welded joint. Additionally, a surface treatment technology for structural optimization based on pulsed barrier discharge（PBD）, which generates low-temperature plasma on the treated metal surface—is presented. It was found that PBD increased the Vickers hardness of 25Kh GNMT structural steel by 20 %（420-510 kg/mm²） at depths up to 2 mm and promoted microstructural refinement of the metal.