0.06C-0.6Si-1.5Mn-0.6Cr双相钢的连续冷却转变

Study on continuous cooling transformation of dual phase steel with 0.06C-0.6Si-1.5Mn-0.6Cr

在Gleeble-1500热应力／应变模拟机上测定了0．06C-0．6Si-1．5Mn-0．6Cr双相钢的未变形和变形连续冷却转变曲线（CCT曲线）．利用光学显微镜对组织进行了观察，利用维氏硬度计对金相组织进行了测定．结果表明，当冷却速度小于10℃／s时，随着冷却速度的增加，贝氏体体积分数和宏观维氏硬度值增加都较为明显；而当冷却速度在10—20℃／s范围内时，无论变形还是未变形时贝氏体体积分数和硬度的变化都趋于平缓．由CCT曲线可知，实验钢经变形后奥氏体向铁素体转变温度在780～550℃之间，在2—20℃／s范围内可以获得贝氏体组织．

The continuous cooling transformation curves without and with deformation of a dual phase steel （0.06C- 0.6Si - 1.5Mn -0. 6Cr） were studied by Gleeble- 1500 thermal -mechanical simulation. Microstruetures were observed by using an optical microscope and the hardness of the specimens was measured. The results showed that the volume fraction of bainite and Viekers hardness increased obviously with the cooling rate increasing when the cooling rate was lower than 10℃/s; while the volume fraction of bainite （both at undeformed and deformed states） and hardness tended to vary gently in the cooling rate range of 10 - 20℃/s. From CCT curves, it can be drawn that γ→α transformation temperature is between 780 - 550℃ for the deformed steel and bainite can be gained in the cooling rate of 2 - 20℃/s.