Effect of severe plastic deformation on microstructure and properties of duplex stainless steel

Abstract

The excellent performance of dduplex and super duplex stainless steels due to their high corrosion resistance and high mechanical strength is directly related to their austeno-ferritic microstructure. However, these steels may suffer the formation of secondary brittle phases when they reach temperatures 600-950°C, with catastrophic service failure of components. In order to understand the influence of the mechanical history of the steel, the equal channel angular pressing (ECAP) was applied on UNS S32750 bar samples, processed by using a hydraulic press (DE-80). Microstructural characterisation was carried out on the severe plastic deformed samples by means of OM, SEM and EBSD. Ultimate tensile strength has improved with a low decreasing of elongation after the first pass. The hardness evolution of the same samples was also evaluated.