Pulsed Electromagnetic Field Effect on Residual Stresses and Strains of Welded Joints of AMg6 Aluminum Alloy

The pulsed electromagnetic field treatment of welded joints is a promising method to improve the mechanical characteristics of metal structures. Its influence on the stress-strain state of welded joints made of aluminum alloy AMg6 is investigated. An original experimental technique for studying the kinetics of electromagnetic field pressure force and pulse electric current during such treatment of metallic materials has been developed. By methods of electronic speckle interferometry, the influence of treatment on the evolution of the residual stress-strain state of samples of annular welded joints in the form of flat disks with thickness δ = 1.0 mm has been studied. Annular welded joints were simulated by depositing “idle” beads along the line of a circle with a diameter of 45 mm with recording the stressed state of disks and displacements of their edges before and after treatment. Treatment was carried out according to two variants: the first variant – disks with δ = 1.0 mm, the second variant – disks with δ = 1.0 mm with additional alloy screen with δ = 5.0 mm. It was shown that as a result of the treatment of disks with δ = 1.0 mm and δ = 1.0 mm + screen in the same mode, the force of electrodynamic pressure increased when a screen was used. In the conditions of screened samples, it is probably caused by an increase in the active volume of the electroconductive medium. It was established that treatment promotes metal structure dispersion and reduces the residual welding stresses.