氮含量对25Mn2CrVS贝氏体型非调质钢组织和性能的影响

研究了N含量(0.016wt%、0.029wt%和0.049wt%)对贝氏体型非调质钢25Mn2CrVS组织和力学性能的影响。结果表明:3组试验钢均为板条贝氏体、粒状贝氏体和铁素体组织,当氮含量从0.016%增加到0.029%时,试验钢强度和韧性增加,组织发生细化,且板条束状贝氏体含量减少,M/A相由长条状变成块状且分布弥散,针状铁素体增加;而氮含量增加至0.049%时,试验钢强度基本不变,韧性急剧下降,组织明显粗化,晶界铁素体形成。固溶钒可以促进板条束状贝氏体在晶界上的形成,奥氏体中析出的VN能够促进针状铁素体的形成。

Effect of nitrogen content on microstructure and properties of 25Mn2CrVS bainite type non-quenched and tempered steel

Effect of nitrogen content (mass fraction of 0.016%, 0.029% and 0.049% respectively) on the microstructure and mechanical properties of 25Mn2CrVS bainite type non-quenched and tempered steel was studied. The results show that the microstructure of all the tested steels consists of lath bainite, granular bainite and ferrite. When the nitrogen content increases from 0.016% to 0.029%, the strength and toughness of the tested steel increase, and the microstructure is refined. When the nitrogen content increases to 0.049%, the strength of the steel is basically unchanged, but the toughness drops sharply, the microstructure is obviously coarsened, and the grain boundary ferrite is formed. Vanadium in solid solution can promote the formation of lath bainite at grain boundary, and VN particles precipitated from austenite can promote the formation of acicular ferrite.