Sulfide stress corrosion (SSC) susceptibilities of duplex stainless steels 2205 produced by powder metallurgy (HIP) and hot rolling

Abstract

Owing to their excellent properties, duplex stainless steels (DSSs) may be selected for the H₂S environment. Operational limits are not defined and depend on fabrication processes. In this work, the susceptibilities of two DSSs 2205 to sulfide stress corrosion (SSC) in saline solutions with three pH levels were investigated. The difference between materials is the fabrication route: hot rolled (HR) tubes and powder metallurgy with compacting and sintering final operations by hot isostatic pressing (PM-HIP). The susceptibility parameters were evaluated by slow strain rate tensile tests (SSRT). Both materials suffered embrittlement in solutions with pH 3.5 and 4.5, but the susceptibility was slightly better in the HR. In the solution with pH 5.5, the HR fractured with ductile behavior, while the PM-HIP was brittle. The better resistance of HR to SSC can be explained by microstructural features, such as the lower grain size and austenite island interspace.