Tensile properties at cryogenic temperatures of austenitic stainless steel and high manganese steel irradiated by fast neutrons at 5K

The tensile tests of experimental SUS304 series stainless steels which have nitrogen contents of 0.003, 0.132 and 0.230 were carried out at liquid helium temperature after fast neutron irradiation at 5K, without any intermediate warm-up. The 0.2% yield strength at liquid helium temperature after the irradiation increased for the no-additional-nitrogen stainless steel and, however, the yield strength became independent of the irradiation with nitrogen content. The tensile strength and martensite volume after the irradiation were not affected by the nitrogen content. A high manganese steel (25 Mn-Cr) was tested at liquid helium temperature after the irradiation at 5K, warm-up to liquid nitrogen temperature. The tensile strength and the 0.2% yield strength have a tendency to increase with irradiation. The effects of irradiation on tensile properties are discussed. (author)