Welding of nitrogen containing austenitic stainless steel using GMAW process

Abstract

In this study, the welding aspects of 21–4-N Nitronic Steel has been considered. It was found that the clusters of carbide were dissolved after solution annealing of the as-received base material at 950 °C and 1150 °C temperatures for 120 min, followed by water quenching. The weld solidification mode was changed from austenite-ferrite at the weld-HAZ interface to ferrite–austenite at the weld center as per their Cr/Ni equivalent ratio. Weld center has minimum austenite and maximum ferrite and this ferrite content decrease towards HAZ (heat affected zone). Further, grain coarsening and carbides dissolution took place due to the heating effect of the weld thermal cycle in multipass welding. The tensile strength was improved after solution annealing for different base metal conditions and weld made on respective base metals. The welding made on 1150 °C solution annealed samples were outperformed.