PSI - Issue 16

Leonid Lobanov et al. / Procedia Structural Integrity 16 (2019) 27–34 Leonid Lobanov, Nikolai Pashсhin / Structural Integrity Procedia 00 (2019) 000 – 000

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The distribution of longitudinal (along the weld line) residual stresses  x before and after EDT are given in Fig. 6. It is seen that the initial maximum  x did not exceed 120 MPa (curve 1). After EDT of welded joint in weld axis the initial values  x in weld were changed from 120 to – 75 MPa (curve 2). After EDT of weld and base metal at 10 mm distance from weld axis (curve 3) the values  x are changed from 90 to – 100 MPa, that is commensurable with EDT of weld centre, By analyzing the data of Fig. 6 it is seen that the maximum effectiveness of electrodynamic effect is reached in EDT in weld axis and base metal near the fusion line (curve 3). The effect of EDT on fatigue resistance of specimens of welded joints of alloy AMg6 of thickness  = 2 mm, made by the automatic TIG (Ar) welding at values of arc voltage, welding current and process speed of U w = 20 V, I w = 170 A, V w = 5.5 mm/s, respectively, was studied. The double-sided treatment of specimens along the line of weld of 90 mm length was made by series of ECP using mode of two-channel EDT at charge voltage U ch = 430 V and capacitance of CES C = 5580  F. The distance between the zones of applying the electrodynamic effects was 5 mm. Fatigue tests for bending the specimens of welded joints were made in machine UPM-02 at symmetric cycle with a range of amplitude of cycle stresses of 2  a = 80…160 MPa.

Fig. 6. Distribution of longitudinal residual stresses  x in transverse section of welded plate of alloy AMg6, curve 1 – initial  x , 2 –  x after EDT along weld axis, 3 –  x after EDT of weld axis and base metal at 10 mm distance from weld axis.

Fig. 7. Results of fatigue tests of specimens of welded joints of alloy AMg6 in coordinates 2 σ а – N, where curve 1 – initial state, 2 – after EDT.