Abstract: The dynamic recrystallization of 10 mm strip of Nb-Ti microalloying low-carbon steel (/% : 0.06C, 0.22Si, 1.80Mn, 0.03Nb, 0.15Ti, ≤0.007N, ≤0.002S) in single pass compression with strain rate 0.1-20.0 s^-1, total deformation 75% at 850 -1100℃ has been tested and studied by using Gleeble 1500 hot simulator. Based on true stress- true strain curves combined work-hardening rate curve it is obtained that the dynamic recrystallization critical strain is 0.4-0.7 and the complete recrystallization strain is 1.1-1.4. The hot deformation activation energy of steel is 618.225 kJ/mol. And based on the Zener-Hollomon equation and dynamic recrystallization status diagram by tested results ,it is obtained the dynamic model of recrystallization of test steel by using Johnson-Mehl-Avrami (JMA) equation method to get the real value of recrystallization volume fraction and by using Epsilon-P model to regress on the test data.

Key words: Nb-Ti Microalloying, Low-Carbon High Strength Steel, Dynamic Recrystallization, Work Hardening Rate, Dynamic Model

摘要： 通过Gleeble 1500热模拟试验机试验研究了Nb-Ti微合金化低碳钢（/%:0.06C,0.22Si,1.80Mn,0.03Nb,0.15Ti,≤0.007N,≤0.002S）10mm带钢在850~1100℃,以应变速率0.1~20.0 s^-1,总变形量75%单道次压缩变形时动态再结晶,由真应力-真应变曲线,结合加工硬化率曲线,得出动态再结晶临界应变0.4~0.7和完全再结晶应变量1.1~1.4。该钢的热变形激活能为618.225 kJ/mol。根据试验结果得到Zener-Hollomon方程和动态再结晶状态图,利用Johnson-Mehl-Avrami（JMA）方程法得到再结晶体积分数实际值,采用Epsilon-P模型对实验数据进行回归,得到试验钢的再结晶动力学模型。

关键词: Nb-Ti微合金化, 低碳高强度钢, 动态再结晶, 加工硬化率, 动力学模型