氮合金化HRB500E钢的静态再结晶行为试验研究

为了对相关热轧工艺制度的确定提供必要的理论依据，采用应力松弛法研究了氮合金化HRB500E钢的静态再结晶行为，运用Gleeble-1500D热模拟试验机分析了不同的应变量、应变温度、应变速率对试验钢静态再结晶的影响，并与普通的钒微合金化HRB500E钢进行了对比. 依据试验结果，以Avrami 方程为基础，建立了两种试验钢的静态再结晶动力学模型，并进行了静态再结晶分数曲线与模型预测值的对比检验. 研究结果表明，控制两种试验钢的应变量在0.4～1.0区间递增，应变温度在950～1 100 ℃范围内递增，应变速率在0.1～1.0 s?1范围内递增时，其t_0.5值（再结晶完成50%所需要的时间）均分别随之减少，再结晶速度加快；其中，应变量及应变温度对试验钢静态再结晶的影响较为显著，应变速率次之. 在应变条件相同的情况下，氮合金化HRB500E钢静态再结晶进程滞后于钒微合金化HRB500E钢. 检验结果表明，两种试验钢静态再结晶动力学模型预测结果与试验结果较吻合. 

Static Recrystallization Behavior of Nitrogen Alloyed HRB500E Steel

In order to provide necessary theoretical basis for hot rolling process, the static recrystallization behavior of nitrogen alloyed HRB500E steel was studied by using stress relaxation method. The effects of various strain capacity, strain temperature and strain rate on the static recrystallization of samples were analyzed with Gleeble-1500D thermal simulation machine. Besides, the results were compared with those of vanadium microalloyed HRB500E steel. Based on the experimental results and Avrami equation, the kinetic models of static recrystallization were established in terms of two kinds of experimental steels, and the static recrystallization fraction curve was compared with the predicted one of the model. The results show that when the strain is increased in the range of 0.4?1.0, the strain temperature in the range of 950?1 100 ℃, and the strain rate in the range of 0.1?1.0 s?1, t_0.5 (time for 50% recrystallization) decreases and the recrystallization speed increases. In particular, the static recrystallization of the experimental steels is more notably affected by strain capacity and strain temperature than strain rate. Under the same strain conditions, the static recrystallization process of the nitrogen alloyed HRB500E steel lags behind that of the vanadium microalloyed HRB500E steel. The verification results show that the prediction results of the kinetic models were in good agreement with the experimental results.