V-N对中碳SiMn非调质钢显微组织的影响

用光学显微镜和透射电镜研究了0.130%V-0.021 5%N、0.130%V-0.0304%N和0.001%V- 0.020 7%N三种V-N含量的(%)0.37～0.38C、0.82～0.92Si、1.78～1.81Mn、0.06 Ti、0.015Nb非调质钢的组织,用Gleeble 1500热模拟机测定了该钢的应力-应变曲线,并用JMatPro 4.1软件计算了该钢的CCT曲线以及900℃和600℃平衡状态下钢中各相的含量。结果表明,该钢的组织为珠光体+先共析铁素体,随氮含量增加,珠光体增多,晶界铁素体变粗;随钒含量减少,珠光体数量显著增加,贝氏体及铁素体变粗;共析铁素体和先共析铁素体中的析出物尺寸≤3 nm;V和/或N含量高的钢,应变时应力大。

Effect of V-N on Microstructure of a Medium Carbon SiMn Non-Quenched and Tempered Steel

Structure of a non-quenched and tempered steel-(%)0.37~0.38C,0.82~0.92Si,1.78～1.81Mn, 0.06Ti,0.015Nb with three different V-N content-(%)0.130V-0.0215N,0.130V-0.0304N and 0.001V-0.0207N was studied by optical microscope and transmission electron microscope,strain-stress curves of the steel were measured by Gleeble 1500 thermal simulation machine and continuous cooling transformation curves of the steel and each phase content in  steel at 900 ℃ and 600 ℃ in equilibrium state were calculated by JMatPro 4.1 software.Results showed that the structure of the steel was pearlite + proeutectoid ferrite; with increasing N content,the amount of pearlite increased with boundary ferrite coarsening; and with decreasing V content,the amount of pearlite increased with bainite and ferite coarsening; the size of precipitates in proeutectoid ferrite and in eutectoid ferrite was ≤3 nm;and the stress during train for steel with higher V and / or N content was larger.