Mechanical Behaviour of Aged High Nitrogen Austenitic Stainless Steels

The present investigation is aimed at studying the effect of ageing on mechanical behaviour of two high nitrogen austenitic stainless steels as these steels are exposed to high temperatures in their applications. Two steels with nitrogen contents greater than 0.6% were given solution treatment and were aged at 500–900°C for 1–100 h. It was found that the steels exhibit superior mechanical properties in solution treated condition while ageing has a deleterious effect on properties due to weak interfaces of depleted austenite matrix and Cr2N lamellae. The plastic flow behaviour can be modeled using modified Ludwik equation in these steels.