The tensile behaviors of vanadium-containing 25Cr-20Ni austenitic stainless steel at temperature between 200 °C and 900 °C

The high-temperature tensile behaviors of two 25Cr-20Ni austenitic stainless steels with different V concentration (0 wt% V and 0.3 wt% V, respectively), have been studied at temperature between 200 ℃ and 900 ℃. The ultimate tensile strength of both steels is strong temperature dependent, which decreases slowly first at 200-300 ℃, keeps platform then at 300-500 ℃ and decreases rapidly afterwards from 600 ℃ to 900 ℃. It is caused by the decreasing strain hardening ability, dynamic strain aging and dynamic recovery together with dynamic recrystallization at different temperatures. At higher than 800 ℃, the elongation of both steels increases markedly due to the dynamic recovery and dynamic recrystallization. However, because of the deteriorated effects of M23C6 precipitates at grain boundary, the elongation of both steels at 700 ℃ does not increase despite decreasing strength. Additionally, the addition of 0.3 wt% V decreases the ductility of the material in the temperature range of 800 ℃ to 900 ℃, which is induced by the impeding effects of solute vanadium on dynamic recovery and recrystallization.