Mechanical and corrosion resistant properties of ATIG welded 2205 duplex stainless-steel via different fluxes

In this study, 6 mm thick duplex stainless-steel grade 2205 plate was welded by active tungsten inert gas (ATIG) using different oxide fluxes and the effect of optimal oxide fluxes on structure, mechanical and corrosion properties was systematically analyzed and discussed. Initially, fourteen oxides were tested (SiO₂, TiO₂, ZnO, MnO₂, Cr₂O₃, Fe₂O₃, ZrO₂, SrO, CaO, MoO₃, V₂O₅, Mn₂O₃, Co₂O₃ and MgO). Among these, three candidate oxides, i.e., SiO₂, Ti₂O and ZnO were selected for further evaluation based on the depth ratio, depth-to-width (D/W), and ultimate tensile strength (UTS) results. By using Minitab 17 software, optimal combinations of these fluxes for maximum penetrations were estimated. The obtained results revealed that the optimal flux composition is 76 % SiO₂-24 % ZnO. The results showed that the depth attained by the optimized flux is 2.9 times greater than tungsten inert gas (TIG) weld. The D/W ratio was also improved 3.7 times when contrasted with typical TIG welding. The energy absorbed in fusion zone in the case of ATIG weld is greater when contrasted with TIG weld. It was found that the weld bead obtained with optimal flux combination in ATIG weld can better withstand sudden loads. The obtained UTS value (810 MPa) for ATIG weld was close to parent metal (825 MPa) and greater than the weld produced by TIG welding (766 MPa). However, the corrosion resistant property was found to be slightly decreased for metal welded with ATIG as compared to metal welded by using TIG. These results give a comprehensive guideline for further investigations on TIG welding of 2205 duplex stainless-steel.