CSP热轧TRIP钢动态再结晶行为研究

摘要：采用Gleeble-3500热模拟试验机，在温度为950~1150℃、应变速率为0.1~10s-1和变形量为65%的条件下研究了CSP热轧TRIP钢的动态再结晶行为，探讨了初始奥氏体晶粒尺寸对TRIP钢动态再结晶行为的影响。研究结果表明，初始奥氏体晶粒尺寸越小，变形温度越高，应变速率越慢时，TRIP钢中奥氏体越易发生动态再结晶。其中，粗晶试样（初始奥氏体晶粒尺寸为767.54μm）在1050~1150℃内变形时，将发生动态再结晶。其热变形激活能为361539.17J/mol，确定了Zener-Holloman参数与应变速率和温度的关系式，建立了动态再结晶临界应变模型、高温奥氏体流动应力模型和动态再结晶晶粒尺寸模型，理论模拟结果与试验结果吻合较好。

Study on dynamic recrystallization behavior of hot rolled TRIP steel produced by CSP process

Abstract：The dynamic recrystallization behavior of hot rolled TRIP steel produced by CSP process was studied by means of Gleeble-3500 thermal simulation testing machine in the temperature range of 950-1150℃ with the strain rate of 0.1-10s-1 and the strain of 65%. And the effect of initial austenite grain size on the dynamic recrystallization behavior of TRIP steel was explored. The results show that the finer initial austenite grain size, the higher deformation temperature and the lower strain rate, the more positive austenite dynamic recrystallization of TRIP steel. Moreover, it is found that when the coarse grained samples (initial austenite grain size is 767.54μm) deform in the range of 1050℃ to 1150℃, the austenite dynamic recrystallization will take place, and the dynamic recrystallization activation energy of TRIP steel is deduced as 361539.17J/mol. The Zener-Hollomon parameter equation as a function of strain rate and temperature is determined. And the model of critical strain for dynamic recrystallization, the flow stress model of austenite at high temperature and the grain size model for dynamic recrystallization are also established. The calculation results are coincided well with the experimental results.