关键词: 奥氏体不锈钢, 钒, 微观组织, 力学性能

Abstract: Influence of vanadium on the microstructure and mechanical properties of 304N austenitic stainless steel was studied by using thermodynamic equilibrium precipitate phase calculation, metallographic and TEM observation, and mechanical property testing. The results show that when the amount of V added is between 0% and 0.6%, with the increase of V content, the austenite grain size of the tested 304N steel gradually decreases, and the tensile strength at room temperature slightly increases, where the strength improvement effect of adding 0.6%V is more significant. The yield strength and tensile strength at tensile temperature of 200-700 ℃ gradually increase, while the elongation slightly decreases. When the amount of N added is between 0% and 0.14%, the strengthening effect of V almost disappears after reducing the N content. The tensile strength at room temperature is similar to that of ordinary 304 steel, and the tensile strength at tensile temperature of 200-700 ℃ is similar to that of ordinary 304 steel, with a little change in elongation. When the amount of C added is 0.04%-0.08%, increasing the C content results in a little change in the room temperature tensile properties of the tested 304N steel, the tensile strength slightly increases after high-temperature tensile test, while the yield strength and elongation do not change significantly. When the V content is 0.3%-0.6% and the Nb content is 0.2%-0.8%, the Nb-V composite reinforcement effect is better than that of single V. The variation of room temperature tensile strength of the as-rolled steel is that single V>Nb-V composite>single Nb, while the room temperature tensile strength of the steel with Nb-V composite alloying in solid solution state is greater than that of single Nb and single V. The values of high temperature yield strength are that single Nb>Nb-V composite>single V, while that of high temperature tensile strength is Nb-V composite>single V>single Nb.

Key words: austenitic stainless steel, vanadium, microstructure, mechanical properties