Influence of carbon and nitrogen on the creep properties of type 316 stainless steel at 873 K

Abstract

This paper is concerned with the creep properties of a nitrogen-alloyed type 316L (316LN) stainless steel (SS) at 873 K in the stress range 215-335 MPa. A comparison has been made with the creep properties of type 316 SS having a similar grain size and chemical composition with respect to the major alloying elements. Type 316LN SS showed a higher rupture life, a lower steady state creep rate and a higher rupture ductility at all stress levels. The improvement in creep properties has been attributed to the combined influence of precipitation strengthening by fine intragranular and intergranular carbides and strengthening arising from the nitrogen in solid solution. Correlations between metallographic observations and the creep properties as well as the role of interstitial elements in these properties are discussed.