Comparative study of activated flux-GTAW and multipass-GTAW dissimilar P92 steel-304H ASS joints

In the present study, welding of P92 steel and 304H austenitic stainless steel (304H ASS) plates (thickness: 8 mm) was performed using activated flux-gas tungsten arc welding (activated flux-GTAW) and compared with the multipass-gas tungsten arc welding (multipass-GTAW). The comparison was done based on weld bead morphology, angular distortion, metallurgical features, mechanical properties, and economics of welding. In activated flux-GTAW, TiO₂ powder (flux) is used to achieve through thickness penetration in single pass, whereas the multipass-GTAW was done in eight passes using the Ni-based filler wire ErNiCr-3/Inconel 82. The results indicated that the activated flux-GTAW process considerably lowered the angular distortion of the welded plates owing to the uniform thermal cycle in single pass. The activated flux-GTAW weldment exhibited better tensile properties with ultimate tensile strength (UTS) as 690.4 MPa and 36.30% elongation. However, the impact strength of weld metal of activated flux-GTAW weldment was quite low due to the formation of untempered martensitic structure. The economic assessment divulged that the activated flux-GTAW process is cost-effective due to no groove preparation and single pass process.