An analysis of tensile behavior of Type 304 stainless steel was conducted for specimens in the solution-annealed condition and after exposure to a sodium environment. The Voce equation was used to describe tensile flow curves for plastic strains above 0.005 at temperatures between 550 and 700°C and strain rates of 3.81 × 10−6 to 1.90 × 10−3 s−1. The results show that, when compared with solution-annealed specimens, the tensile flow behavior of the sodium-exposed specimens is characterized by a higher strain-hardening rate, which decreases rapidly with an increase in flow stress. The values of the saturation stress for uniform elongation predicted from the Voce model are higher for the sodium-exposed specimens than for those in the solution-annealed condition at strain rates ≲5 × 10−5 s−1 and lower for strain rates ≳5 × 10−5 s−1. Metallographic examination of the fracture surfaces shows a transition from a complete ductile fracture to a partial intergranular failure as the strain rate decreases. Carburization of the specimens appears to inhibit the intergranular failure.
Effect of Direction Change in Maximum Principal Strain Axis on Multiaxial Low Cycle Fatigue Life of Type 304 Stainless Steel at Elevated Temperature.
