The study of sigma and carbide in cast austenitic stainless-steel grade HH after 24 years of high-temperature service.

Cast austenitic stainless steel (CASS) has been widely used for long-term service periods in high-temperature applications. Nonetheless, the behavior of CASS after high-temperature and long-term service is insufficiently researched alongside the microstructural analysis for sigma phase and carbide. Here, intermediate pipe support made from CASS grade HH was investigated after 24 years of service at 700 °C and compared with the solution-treated specimen at 1100 °C for 2 h.