EFFECTS OF LARGE NEUTRON DOSES AND ELEVATED TEMPERATURE ON TYPE 347 STAINLESS

Abstract

Tests of subsize tensile and impact specimens of Type 547 stainless steel irradiated in three capsules to fastneutron exposures of up to 1.1 x 10/sup 22/ nvt were conducted. Ductile fractures at impact energies of 65 ft-lb, representing a 35% decrease in impact strength, were noted at room temperature. Impact energies of approximates 20 ft-lb and a fracture with both brittle and ductile characteristics were observed at -300 deg F. Irradiation-induced property changes included increases in yield strength from 35,000 to 105,000 psi and in ultimate strength from 90,000 to 112,000 psi and a decrease in total elongation from 63 to 31% at room temperature. A 600 deg F anneal produced no measurable recovery of preirradiation properties for periods up to 144 hr, but a large degree of recovery was obtained by annealing 1 hr at 1800 deg F. In material irradiated at 750 deg F, increases in yield strength from 55,000 to 149,000 psi and in ultimate strength from 92,000 to 149,000 psi, decreases in elongation from 55 to 10%, and reductions in area from 70 to 60% were observed. (H.G.G.)