Dissimilar Welding of Cast Alloy 706 with Different Prior Heat Treatment Conditions and Austenitic Stainless Steel 321

Abstract

Abstract The welding of dissimilar joints is most common in the aerospace applications, especially, cast nickel-based superalloys are welded with austenitic stainless steel for high-temperature service conditions. It is well known that heat-affected zone (HAZ) cracking is a common phenomenon while welding age-hardened alloy 706. In this study, an alloy equivalent to cast alloy 706 subjected to three different heat treatment cycles and was welded with annealed austenitic stainless steel 321. The HAZ on the alloy 706 was investigated, and it was found that the HAZ of alloy 706 that underwent stabilization heat treatment was free from microfissures. The fusion zone microstructures were also investigated. The mechanical properties were evaluated, and it was found that the alloy 706 welded in stabilized and age-hardened condition furnished better mechanical properties than in both room temperature and elevated temperature.