V-N对中碳SiMn非调质钢显微组织的影响

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

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JMatPro4.1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。

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. 021 5N, 0. 130V- 0.030 4N and 0. 001V- 0.020 7N 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 JMatPro4.1 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 ferrite 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.