Mechanical properties of stainless steels at 20 to −253°C

Conclusions

• 1. In steels with stable austenite the yield strength and ultimate strength increase considerably with decreasing testing temperatures. The rate of increase in strength increases with decreasing temperatures.

• 2. The formation of nickel martensite during plastic deformation additionally increases the ultimate strength, while the plasticity of notched samples remains satisfactory down to −253°C. The formation of martensite alloyed with manganese greatly reduces the plasticity at −253°C, which in turn causes a decrease of σ_b and σ ⁿ_b by comparison with their values at −196°C.

• 3. Manganese, nickel, and chromium have a negligible effect on the strengthening of austenite at 20 to −253°C.

• 4. The plasticity of stable chromium-nickel austenitic steel at low temperatures, determined on smooth and notched samples, depends little on the composition or temperature at 20 to −253°C; the plasticity of stable chromium-manganese austenite increases somewhat with increasing concentrations of manganese but remains lower than in chromium-nickel steel with approximately the same concentration of alloying elements at −196 and −253°C.