Comparison Between Hot Rolled and Powder Metallurgy–Hot Isostatic Pressing (PM-HIP) Processed Duplex Stainless Steel UNS S32205

Duplex stainless steels (DSS) have been selected to many applications in petrochemical industries. One of these applications is in manifolds and pieces for the oil and gas production. Some pieces may be produced by forming (forging and rolling) or powder metallurgy with high isostatic pressing (PM-HIP). Thus, PM-HIP can be used for complex geometries with minimum or no machining operations, being so called near net shape process. The HIP step is the compacting and sintering operation occurring together, under isostatic stress state, high temperature and inert atmosphere. HIPed products show very low level of porosities to achieve structural quality level. In this paper a hot rolled and a PM-HIP DSS with similar composition were compared as regard to microstructure, mechanical and pitting corrosion resistance. The results show that the HIPed DSS is isotropic and has very fine grain size, while the wrought steel has the typical microstructure of elongated islands of austenite and ferrite. The longitudinal specimen of the hot rolled tube presented higher impact toughness at − 46 °C, despite of the very fine grain size of the HIPed steel. The flow stress curve of both materials were modeled and compared.