Effects of Soaking Time and Cold Work on Sensitisation of Austenitic Stainless Steels

Abstract

The effects of soaking and coldworks on sensitisation of austenitic stainless steels were studied. Annealed and samples coldworked to 20% and 40% were subjected to sensitisation heat treatment at 650 C for 24 and 72 hours. Metallographic analysis carried out showed that sensitisation occurred in both annealed and coldworked samples which manifested as ditches. Soaking for 72 hours showed more ditches than 24 hours. Intergranular ditches were more prevalent in annealed and lower coldworked samples. In contrast, heavily coldworked samples were more susceptible to transgranular carbide precipitation evident by ditches on slip bands and recrystallised grains.