Investigations on the role of Inconel 82 additions on improving fatigue and corrosion behaviour of gas tungsten arc AISI 316L stainless steel claddings

Abstract

In the present work, single- and double-weld layers of Inconel 82 were added to 316L stainless steel claddings using the gas tungsten arc welding process with the aim of improving the fatigue and sensitization performance of such clad overlays. These overlays were subjected to a high-temperature sensitization treatment of 750˚C/24 h (air-cooled) to induce precipitation, and then solution treated at 1050˚C/2 h (furnace-cooled) to mitigate the ill effects of intermetallic precipitation. Carbides of types Cr23C6 and Cr7C3 were detected in the aged 316L clad, which occurred interdendritically. These deleterious phases decreased the fatigue crack growth resistance of conventional 316L, but the addition of Inconel 82 resulted in inducing crack-arresting tendencies in it and thus significantly increasing its resistance against fatigue crack propagation. Solution annealing treatment resulted in the dissolution of deleterious phases, due to which the fatigue performance of these clads improved significantly. Among all the specimens, 316L clad with the double layer of Inconel 82 in the solution-annealed condition offered the highest resistance to fatigue crack growth. Corrosion performance evaluated via sensitization studies shows that ageing degraded the corrosion performance of 316L weld overlays, but the addition of Inconel 82 improved it. This study establishes that the addition of Inconel 82 can significantly improve the fatigue and corrosion performance of conventional 316L weld claddings.