Microstructure and intergranular corrosion behavior of HAZ in DP-TIG welded DSS joints

In this study, 10.8-mm-thick workpieces of S32101 duplex stainless steel were welded using a keyhole deep penetration tungsten inert gas welding system. The misorientation angle distribution of grain boundaries in the heat affected zone was analyzed using the electron backscatter diffraction technique. Double-loop electro-chemical potentiokinetic reactivation tests were performed to assess the intergranular corrosion resistance, based on the degree of sensitization. The volume fractions of ferrite and austenite and the grain boundary misorientation angle affect the intergranular corrosion of the welded joints. The relationship between the grain boundary misorientation angle of the austenite and the degree of sensitization was established. The volume fraction of austenite and the frequency of Sigma 3 coincidence site lattice boundary, increases with the increasing heat input. The misorientation angle distribution in the austenite, the frequency of Sigma 3 coincidence site lattice boundary, and the volume fraction of CrN influence the intergranular corrosion resistance of the heat affected zone.