26MnB5钢的动态再结晶行为

Dynamic recrystallization behavior of 26MnB5 steel

利用Gleeble-1500热模拟压缩试验获得了26MnB5钢在880~1 000℃、0.01~10s-1、最大变形55%条件下的真应力-真应变曲线,研究了26MnB5钢在试验条件下的动态再结晶行为。结果表明：26MnB5的真应力-真应变曲线在高温、低应变速率条件下出现明显峰值点特征,意味着样品发生了动态再结晶;26MnB5再结晶程度和奥氏体晶粒均匀度随温度的增加或应变速率的降低而提高,而晶粒平均尺寸则表现出先减小后增大的趋势;利用Johnson-Mehl-Avrami（JMA）方程可以建立26MnB5钢动态再结晶动力学模型,模型预测值与实测值基本吻合。

True stress and true strain curves of 26Mnt35 steel were obtained through high temperature compression test of the temperature range of 880-- 1 000 ℃, the strain rate of 0.01 -- 10 s 1 and the maximum deformation of 55% on Gleeble-1500 thermal simulator. The dynamic recrystallization behavior of 26MnB5 steel was investiga- ted. It turns out that the true stress and true strain curves at the conditions of high temperature or low strain rate are characterized by obvious peak point, which means some level of dynamic recrystallization happens. With the rising of temperature or the lowering of strain rate, the degree of recrystallization and the uniformity of austenitic grain size increases, while the average grain size decreases first and then increases. The kinetic model of dynamic recrystallization for 26MnB5 steel can be established using Johnson-Mehl-Avrami （JMA） equation and the soften- ing fraction predicted by the kinetic model is consistent with the measured value.