Effect of the welding procedure on the deformation of superposed welds of a low carbon steel

This study compared gas-metal arc welding (GMAW) and laser beam welding (LBW) for the superposed joining of two low-carbon steels. The motivation was to reduce the visible defects (notches) in the external part of one of the sheets. Both welding processes produced sound welds characterized by ferrite and pearlite; however, the notch disappeared when LBW was used. The hardness values of the fusion and heat-affected zones were similar for both processes, but the tensile strengths were very different. The shear tensile strengths of the LBW and GMAW were 415 and 84 MPa, respectively. Finite element analysis simulations indicated a more diffuse distribution of the von Mises stress throughout the welded component. The GMAW FEA model also presented a defect because of excessive heat transfer and residual stresses. In conclusion, LBW can replace GMAW in this particular case with improvements in appearance, productivity, and mechanical strength.