Abstract:
Nitrogen alloyed low carbon grade 316L(N) stainless steel (SS) is a major structural material for high
temperature structural components of sodium cooled fast reactors. With a view to significantly enhance
the high temperature mechanical properties of 316L(N) SS and thereby increase the design life of struc-
tural components from 40 years to 60 years, the influence of nitrogen content on the tensile and creep
properties of this steel has been investigated. Four heats of 316LN SS with 0.07, 0.11, 0.14, and 0.22 wt.%
nitrogen were used in this investigation. Tensile tests were carried out at various temperatures between
room temperature and 850 ◦ C. Creep tests were carried out at 650 C at various stress levels in the range
of 140–225 MPa. The maximum rupture life in these tests was 16,000 h. The tensile and creep data were
analysed according to RCC-MR nuclear code procedures and the design curves have been generated. The
tensile and creep strength of 316L(N) SS have been found to improve significantly by increasing the
nitrogen content.
