High temperature deformation behaviour of an industrial S32760/1.4501/F55 super duplex stainless steel (SDSS) alloy

摘要

Super Duplex Stainless Steels (SDSS) are the best option when high mechanical resistance, associated with very good stress corrosion cracking resistance, excellent resistance to pitting and crevice corrosion and increased thermal conductivity are required. This combination of properties makes them very attractive for a number of applications in chemical and petrochemical industry, such as components for offshore oil and gas extraction installations. Unfortunately, the fabrication and processing of these alloys are more difficult than other stainless steels and under certain conditions embrittlement may occur. In order to investigate the phenomenon of cracking registered during the industrial hot forging of an F55 Super Duplex Stainless Steel, some studies were made regarding the phase composition, microstructural and mechanical properties after hot deformation in various conditions. Modern investigation techniques, such as Scanning Electron Microscopy (SEM), Electron Back Scattering Diffraction (EBSD), microhardness testing and fractographic analysis were used, which enabled to draw some useful conclusions concerning the influence of hot deformation on the main microstructural and mechanical characteristics of the investigated F55 Super Duplex Stainless Steel.