2Cr12NiMo1W1V超临界汽轮机叶片用耐热钢的热变形行为

 为了解决2Cr12NiMo1W1V耐热钢在锻造过程中晶粒粗大和组织不均匀的问题，利用Gleeble-3800热模拟试验机，在变形温度为1 000～1 200 ℃、应变速率为0.01～10 s－1、变形量为70%的条件下，研究和分析了2Cr12NiMo1W1V耐热钢的高温塑性变形和动态再结晶行为。结果表明，该耐热钢的真应力-应变曲线具有动态再结晶特征。再结晶晶粒尺寸随着变形温度的增加或应变速率的降低呈增加趋势，在变形温度为1 150～1 200 ℃，应变速率为0.01 s－1时，晶粒尺寸急剧增加。在真应力-应变曲线的基础上，建立了材料热变形本构方程，其热激活能为453.74 kJ/mol。根据峰值应力绘制了合金的热加工图并获得在各加工条件下的效率值，合金的最佳热加工区间为变形温度为1 000～1 150 ℃、应变速率为0.1～1 s－1以及变形温度为1 060～1 125 ℃、应变速率为0.1～10 s－1。

Hot deformation behavior of 2Cr12NiMo1W1V heat resistant steel used for supercritical steam turbine blades

In order to solve the problem of coarse grain and microstructure uniformity of 2Cr12NiMo1W1V heat resistant steel during forging process，the hot deformation characteristics and dynamic recrystallization behavior at the temperature range of 1 000-1 200 ℃ and strain rate range of 0.01-10 s－1 under 70% deformation were investigated by means of hot compression tests with Gleeble-3800. The results show that the true stress-strain curve of the alloy has dynamic recrystallization characteristics. The recrystallized grain size increases with the increase of deformation temperatures or the decrease of deformation rates. The grains grow fast when deform at 0.01 s－1 with temperature range of 1 150-1 200 ℃. The constitutive equation is established on basis of the true stress-strain curves and the activation energy（Q）was obtained as about 453.74 kJ/mol. The hot working maps are developed based on the peak stress and show variations of the efficiency of power dissipation related to temperature and strain rate. The optimum hot working temperature and strain rate interval are 1 000-1 150 ℃ and 0.1-1 s－1，1 060-1 125 ℃ and 0.1-10 s－1 respectively.