Effect of surface nanocrystallization on the sensitization and desensitization behavior of Super304H stainless steel

Abstract

An attempt has been made to understand the sensitization and desensitization behavior of the shot-peened Super304H during aging around service temperature. The results show that strain-induced α⿲-martensite was blamed mainly for the significant increase of the degree of sensitization (DOS) of shot-peened Super304H when aged at 600°C. However, the DOS decreased greatly when aged at 650°C for 24h or 700°C for 2h, indicating a faster self-healing process of chromium depletion zones due to long range Cr diffusion enhancement by surface nanocrystallization and also the reverse transformation of α⿲-martensite to austenite at the same time.