Electric Pulse Component Effect on the Stress State of AMg6 Aluminum Alloy Welded Joints Under Electrodynamic Treatment

The residual welding stresses deteriorate the welded joint lifetime, and they are the chief cause of brittle metal fracture, i.e., corrosion cracking. The development of efficient methods to reduce the welding stresses, which are noteworthy for low energy costs and ease of realization, is customary important for the modern welding production. One such method is the electrodynamic treatment (EDT) based on the electric current pulse passing through the welded joints at the instant of dynamic load application to it. In the optimization of the parameters it is appropriate to test the pulse electric current effect on the residual welding stresses. The procedure of investigation of the EDT electric pulse component effect on the stress state of AMg6 aluminum alloy welded joints is proposed. It is established that the electric current pulse passing through the welded joint metal enhances the EDT efficiency in reduction of residual welding stresses. It is shown that the electrodynamic effect initiates the plastic tensile strains in metal, their interaction with the plastic welding compressive strains reduces residual stresses in the welded joint. Here the electric current pulses passing increases the peak values of the plastic tensile strains, which results in the more efficient electrodynamic effect on the residual welding stresses decrease in AMg6 alloy. The results lend credence to the physical model describing the electroplastic effect on the welding joints’ stress state.