Austenitic stainless steels are susceptible to caustic stress corrosion cracking (SCC) above 121°C. When sulfides are present in caustic solutions the SCC has been reported to occur at lower temperatures. This paper discusses a study of the role of sulfide in caustic solutions on SCC of austenitic stainless at T=~50°C.
Assessment of sigma phase embrittlement in austenitic stainless steels such as Type 304H, commonly used in fluid catalytic cracking (FCC) units. Other austenitic stainless steels used in other refining process units are also discussed. The detection and measuring of the amount of sigma phase were made using metallography.
A laboratory study was performed by exposing seven candidate heat exchanger alloys to simulated 2 (sCO2) Brayton power cycles. The alloys, consisting of fineirtriaitilcly s 3te.6e%ls ,O austenitic stainless steels, and nickel-base alloys, were exposed to impure CO2 containing 2 and 5.3% H2O at a constant pressure of 200 bar.
Case study: Cracking occurred in a (UNS S32100) type austenitic stainless steel nozzle fitting at a low point in the reactor effluent piping in a Gasoil Hydrotreater unit following start up. Normal preventive measures had been taken. The failed sample was removed for metallurgical analysis and determination of mechanism(s).