Numerical and experimental investigation of residual stresses in magnetically impelled arc butt welded joints in low alloy steels

摘要

Numerical modeling of multi-physic manufacturing processes such as welding has been always a complex task when it involves phase changes. In this paper, a finite element model for simulation of the heat transfer, phase transformation, and mechanical analysis of magnetically impelled arc butt welding of low alloy steels is presented. Both effects of volumetric dilatation and transformation-induced plasticity were considered in the mechanical analysis. Series of welded joints were prepared in various welding conditions by using magnetically impelled arc welding machine. Microstructure and residual stresses of a sample were used to verify numerical results. To highlight the importance of volumetric dilatation and transformation-induced plasticity effects, the numerical results were compared with and without the mentioned effects. While without considering phase transformation effects maximum circumferential stresses on weld line reached 260 MPa, consideration of phase volume changes reduced it to - 60 MPa and further consideration of transformation-induced plasticity (TRIP) decreased it to - 70 MPa. On the other hand, the residual stress in the axial direction in this point without considering phase transformation effects was near + 5 MPa while it was near - 90 MPa and - 25 MPa considering just phase volume changes and phase volume changes together with TRIP effects, respectively.