Abstract
A low carbon, nitrogen alloyed version of stainless steel type 316 (SS 316L(N)) is the current choice as structural material for fast breeder reactors, and there is a need to derive reliable stress rupture correlations for life extrapolation. The present paper demonstrates the success of the heat correlation proposed by Ray, Sasikala and Rodriguez in deriving multiple heat isothermal correlations for stress rupture data for a large number of heats of SS 316L(N) from the European Commission's Working Group. This method of using multiple heat data as the knowledge base allows reliable correlations and extrapolations also for individual heats, even when the available data are inadequate for meaningful single heat stress rupture correlations. It is also shown, concatenating data for SS 316L(N) heats with those for two groups of SS 316 grade material (from the National Research Institute of Metals), that as far as heat dependence of stress rupture life is concerned, it is possible to consider SS 316L(N) heats as belonging to the SS 316 group. The isothermal ‘reference’ correlations thus derived are robust because of the large number of heats and the volume of data in the concatenated database for SS 316 and SS 316L(N) grades.
Get full access to this article
View all access options for this article.