Long-term creep rupture behavior of smoothed and notched bar specimens of low-carbon nitrogen-controlled 316 stainless steel (316FR) and their evaluation

Low-carbon, nitrogen-controlled 316 stainless steel is regarded as a principal candidate for a main structural material of future fast breeder reactor plants in Japan. To grasp creep deformation and rupture behavior of this steel whose modeling is indispensable in the design of high-temperature components, a number of uniaxial tensile creep tests have been conducted for four products of this steel at 550 °C and higher temperatures. Long-term creep rupture data up to about 94,000 h were obtained and used to examine the applicability of rupture and deformation estimation methods developed earlier. In addition, two tests were conducted using round-bar specimens with circumferential notches to make investigation of the effect of stress multiaxiality on creep damage.