Increasing fatigue fracture resistance of welded joints by controlled synchronization of electrodynamic actions

Keywords

electrodynamic treatment, electrode device, one- and two-channel circuit, re­sidual welding stresses, aluminum alloy, durability, electric current pulse, cycle amplitu­de, eddy currents, electroplastic effect, plastic deformations, pulsed electromagnetic field.

Cite as

Lobanov L. M., Pashchin, N. A., Mikhodui O. L., Shlonskyi P. S., Chopyk V. V., and Karlov O. M. Increasing fatigue fracture resistance of welded joints by controlled synchronization of electrodynamic actions. Physico¬chemical Mechanics of Materials. 2022. 58(2), 005-011.

Abstract

The use of modern welded transport structures made of aluminum – based alloys requires the development of promising methods for extending their life, one of which is electrody­namic treatment (EDT). EDT helps to increase the durability of welded joints by optimi­zing the stress-strain state in the area of the expected fatigue failure. The use of micropro­cessor control in two-channel EDT allows us to increase the processing efficiency due to the controlled synchronization of the components of electrodynamic actions in comparison with a single-channel EDT. During fatigue tests of experimental welded samples of AMg6 aluminum alloy for the amplitude values of the cycle 2σ_a = 80–160 MPa single-channel and two-channel EDT provide an increase in their durability N, respectively, in 2.0–2.4 and 2.2–2.7 times despite the fact that two-channel EDT was realized at three times lower energy costs in comparison with a single-channel one. The consequence of the exclusion of the pulsed current passage through the prototype in the two-channel EDT is a decrease of the parameter in N 1.5 times compared to EDT with the passage of current, which is as­sociated with the exclusion of the electropulse component, which intensifies the relaxation of residual welding stresses due to electroplasticity. The two-channel EDT of the weld and fusion line doubles the value of N compared to the treatment of the weld alone, which is due to the propagation of the compression stress zone on the fusion line, which provides a smaller range cyclic stresses compared to the resulting EDT weld.

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