Modeling of Heat Affected Zone in Multipass GMAW Surfacing S235 Steel Element

The paper presents the model of heat affected zone in a steel element during multipass Gas Metal Arc Weld surfacing. The temperature field is described analytically assuming a volumetric model of heat source and a semi-infinite body model of the surfacing workpiece. The solution takes into consideration the heating during overlaying subsequent weld beads and self-cooling of already padded areas. The critical temperatures A1 and A3 are used to determine partial and full austenitic transformation zones, while the temperature of solidus is used to determine the fusion line. Kinetics of phase transformations during cooling is determined on the basis of TTT-welding diagram. In description of phase transformations progress the J-M-A-K law for diffusive transformations, and the K-M law for martensitic transformation are used. The results of calculations are presented in the form of temperature and volume phase fraction distributions.