Microstructural Study and Corrosion Performance of Duplex and Superaustenitic Steels in Sour Well Environment^⋆ Available to Purchase

A study has been made of mill-annealed and cold-worked duplex Dalmine D22 and D25 stainless steels (75 and 140 ksi) and of cold-worked superaustenitic Dalmine D28-32 steel (110 ksi). The materials have been tested under conditions typical of oil and natural gas wells operating in a severe environment. The effect of environment variables (T, pCO₂, pH₂S, NaCl concentration, and pH) and cold-working on corrosion properties, particularly sulfide stress corrosion cracking (SSCC), has been investigated. Engineering diagrams have been produced for qualification and selection of the most suitable material for use in a given environment. For duplex steels, the corrosion mechanisms in relation to environmental variables, applied stress, and microstructure have been examined from the microstructural aspect.