The influence of liquid sodium on the creep-rupture behaviour of SS AISI 316 L(N)

To determine the influence of sodium on the creep-rupture behaviour of 316 L(N)-steel 42 tests in sodium and 36 tests in air at 550degC have been performed. No effect of sodium was found to be significant for the material tested in the as-received condition. For components starting operation in the non-sensitized condition in high purity sodium design can be based on in-air data. It can also be concluded that the mechanical properties of thin-walled components will not be influenced by the sodium environment. Provisional reservations in respect to design rules should be made for sensitized material, since additional creep rupture tests on previously sensitized material show somewhat shorter times-to-rupture and onset of tertiary creep in sodium than in air. An assessment for thin-walled components (d < 4 mm) starting operation in the sensitized condition has to be based on the metallographic post test examinations of the in-sodium tested specimens. (author)