Microstructural characterization, mechanical, and intergranular corrosion of an Inconel 625 - AL6XN super austenitic stainless steel welded joint

The microstructural features of a dissimilar welded joint play an important role in the mechanical and corrosion behavior during the fabrication of metallic components in the energy generation industries. This research was conducted to measure the corrosion resistance and mechanical properties of a dissimilar weld made of an Inconel 625 and AL6XN super austenitic stainless steel using pulsed-gas metal arc welding with an ERNiCrMo-3 filler metal. The microstructural observation revealed the growth of the prior recrystallized grains in the heat-affected zone of the Inconel 625 alloy. In contrast, the heat-affected zone of AL6XN showed small changes in the grain size. The AL6XN/weld-metal interface exhibited the formation of non-mixed and partially melted zones. Furthermore, the results showed that the ultimate tensile strength (UTS) and the yield stress (σ_y) of the welded joint exhibited higher values than those of the AL6XN as-received material. Finally, the AL6XN/weld-metal interface presented lower resistance to intergranular corrosion.