SA508 Gr.3Cl.1钢动态再结晶行为研究

Research on Dynamic Recrystallization of SA508 Gr.3Cl.1 Steel

通过在热模拟试验机Gleeble-1500上对SA508 Gr.3Cl.1钢进行变形温度为950~1 200℃、应变速率为0.001~1 s;的等温压缩试验,研究了其在高温热变形时的动态再结晶行为。基于P-J法确定了临界应力和临界应变,建立了其与热变形参数Z之间的数学模型。基于改进的Avrami方程建立了SA508 Gr.3Cl.1钢的动态再结晶动力学模型。以变形温度和应变速率为变量建立了动态再结晶尺寸模型。研究结果表明:SA508 Gr.3Cl.1钢在高温低应变速率下,更容易发生动态再结晶。在动态再结晶进行充分的情况下,温度越高,应变速率越低,动态再结晶晶粒尺寸越大。动态再结晶尺寸模型计算值与试验值之间的相关系数达0.97。

The dynamic recrystallization behavior of SA508 Gr.3 Cl.1 during high temperature deformation was studied by isothermal compression tests at temperature of 950 ~ 1 200 ℃ with strain rates of 0. 001 to 1 s-1,which was conducted on Gleeble 1500 simulator. The critical stress and strain were determined by P-J method,and the mathematical models representing the relation of them and deformation parameter Z were established.The dynamic recrystallization kinetic model based on the improved Avrami equation and the grain size model with the deformation temperature and strain rate as variables were established. The results show that the dynamic recrystallization is prone to occur at high temperature and low strain rate for SA508 Gr.3 Cl.1. And the dynamic recrystallized grain size is larger at the higher temperature or the the lower strain rate when the dynamic recrystallization occurs completely. The correlation coefficient between the calculated value of the dynamic recrystallization size model and the experimental value is 0.97. Therefore,this model can predict the dynamic recrystallization grain size of SA508 Gr.3 Cl.1 during thermal deformation.