17CrNiMo6钢的静态再结晶行为

采用Gleeble-1500热模拟试验机,在压缩温度为950~1050 ℃(间隔50 ℃)、预应变为0.1~0.2(间隔0.05)、应变速率为0.01~1 s^-1、不同原始晶粒尺寸和道次间隔时间条件下,对17CrNiMo6钢进行双道次热压缩试验。讨论了道次间隔时间、压缩温度、预应变、应变速率和原始晶粒尺寸对17CrNiMo6钢静态再结晶行为的影响。根据回归分析得到静态再结晶在不同变形条件下的流变应力曲线,结合压缩后试样的显微组织,建立了17CrNiMo6钢静态再结晶动力学模型和晶粒尺寸模型。结果表明,17CrNiMo6钢静态再结晶体积分数随压缩温度、间隔时间、预应变和应变速率增加而增大;静态再结晶晶粒尺寸随压缩温度和原始奥氏体晶粒尺寸增加而增大,随预应变和应变速率的增加而减小。通过对比所建模型的预测值与热压缩所得的试验值,发现二者较为吻合,验证了模型的准确性。

Static recrystallization behavior of 17CrNiMo6 steel

Under the conditions of compression temperature of 950-1050 ℃(interval 50 ℃), prestrain of 0.1-0.2 s^-1(interval 0.05), strain rate of 0.01-1 s^-1, different prior grain sizes and different pass intervals, double-hit hot compression test of the 17CrNiMo6 steel was carried out on Gleeble-1500 thermo-mechanical simulator. The effects of pass interval, compression temperature, prestrain, strain rate and prior grain size on static recrystallization behavior of the 17CrNiMo6 steel were discussed. According to the microstructure of the specimens after compression and the flow stress curves of static recrystallization under different deformation conditions obtained by regression analysis, the static recrystallization kinetics model and grain size model of the 17CrNiMo6 steel were established. The results show that the volume fraction of static recrystallization increases with the increase of compression temperature, interval time, prestrain and strain rate. The grain size of static recrystallization increases with the increase of compression temperature and prior austenite grain size, while decreases with the increase of prestrain and strain rate. By comparing the predicted results by the models with the experimental values of thermal compression test, it is found that the two are in good agreement, which proves the accuracy of the models is high.