Study of Residual Stresses in Welded Joints of Heat-Resistant ML10 Magnesium Alloy After Electrodynamic Treatment

Abstract

Airframes from ML10 magnesium alloy are repaired using argon-arc welding with nonconsumable electrodes. The residual stresses occurring in the repair welds deteriorate the operating characteristics of restored parts. The presence of residual stresses necessitates postweld heat treatment, which increases the prime cost of repair operations. This implies the option of applying the alternative methods of weld stress state adjustment, including the electrodynamic treatment, which make it possible to reduce the level of residual stresses in welded joints and, thus, the cost of repair welding operations for airframes from this alloy. The results of the performed experiments show that electrodynamic treatment allows one to reduce the initial level of stresses in welded joints (which reaches 120 MPa) to 30 MPa and to form, at definite geometric characteristics of specimens, compression stress fields in the treatment zone, whose values reach –50 MPa. It is demonstrated that the optimal distance between the treatment zones is 5 mm, which ensures granted overlapping of electrodynamic action zones and, hence, the maximum effectiveness of electrodynamic treatment.