Comparative mechanical and microstructural analysis of heat input on duplex SS/austenitic SS by TIG weld

Comparative analysis of variable heat infusion (Low/High heat infusion) over dissimilar metal comprises of Duplex stainless steel (DSS) 2205 and Austenite stainless steel (ASS) 304L has been executed with support of TIG welding. For joining the plates, we use ER309L & ER2209 with lower heat involvement (LHI) and higher heat involvement (HHI). Because of the ferrite/ austenite phase balance, weld zone, HAZ, and interface hardness do not show any discernible changes as heat input increases. LHI weldment shows great amount of ductile nature. According to the characterization of the specimen LHI may be more useful for structure integrity of the weld than HHI. We found evidence of (γ2) precipitation in the HAZ of the HHI. We found 29% & 55% for 309L under LHI and HHI and 61% & 30% for 2209 filler ferrite under LHI and HHI respectively. We also observed avg. values for hardness as 241.29Hv, 265.40Hv, 247.48Hv & 267.03Hv for filler 309L HHI, 2209 HHI, 309L LHI & 2209 LHI respectively. The Sec. austenite phase development and larger particle size are the causes of the decrease in impact toughness value. The occurrence of γ2 precipitate particles in the WZ indicates the presence of tensile fracture for HHI weldment.