Cracking susceptibility after post-weld heat treatment in Haynes 282 nickel based superalloy

Abstract

This paper presents a study of the standard post-weld heat treatment (PWHT) behaviour of autogenous laser welded γ′ age-hardenable precipitation strengthened nickel based superalloy Haynes 282 (HY 282). The study involves a careful and detailed microstructural characterisation as well as an analysis of the weld cracking susceptibility during welding and Gleeble thermo-mechanical physical simulation. Various factors that could influence post-weld cracking in superalloys weld were experimentally examined. Our microstructural examination of the as-solution heat treated (SHTed) material and the thermo-mechanically refined grain material shows that intergranular heat affected zone (HAZ) cracking is observable in only the as-welded SHTed material. There was no indication of post-weld heat treatment cracking in all welded materials. Our conclusion, in this study, is that the chemistry of superalloy HY 282 which aids the preclusion/ formation of deleterious solidification microconstituents during welding as well as its relatively slow aging kinetics enhances its resistance to PWHT cracking.