14Cr-ODS铁素体钢的热变形行为及热加工图

利用Gleeble-1500D热模拟实验机研究机械合金化法制备的14Cr-ODS铁素体钢在变形温度为1 050~1 200℃、应变速率为0.001~0.3 s 1条件下的高温变形行为,测定其真应力真应变曲线,分析流变应力随应变速率以及变形温度的变化关系。应用MATLAB软件计算最佳的应力水平参数,通过线性回归分析得出材料的变形激活能、材料常数和材料的双曲线本构方程,构造14Cr-ODS铁素体钢的热加工图。结果表明:14Cr-ODS铁素体钢的流变应力随温度升高而减小,随应变速率增加而增大;其变形激活能为501.11 kJ/mol,最佳应力水平参数为0.007,应力指数为4.08;加工失稳温度区域为1 050~1 100℃,应变速率区域为0.1~0.3 s 1;适合加工的条件是变形温度为1 150℃,应变速率为0.1 s 1。

Hot deformation behavior and processing map of a 14Cr-ODS ferritic steel

Hot deformation behavior and true stress-true strain curves of 14Cr-ODS steel prepared by mechanical alloying technology were investigated by conducting hot compression deformation tests on Gleeble-1500D simulator at the deformation temperature range of 1 050~1 200 ℃ and the strain rates of 0.001 s 1~0.3 s 1.The relationships between rheological stress and strain rate,as well as rheological stress and deformation temperature were studied.The optimum value of stress was calculated by MATLAB software.Based on the obtained data,activation energy,stress parameter and material parameters in the hyperbolic-sine equation were resolved.On basis of dynamic materials model,the processing map of 14Cr-ODS steel was proposed.The results show that the flow stress decreases with increasing temperature and decreasing strain rate.Activation energy for the hot deformation of 14Cr-ODS ferritic steel is about 501.11 kJ/mol,and the stress index and best stress parameter are 4.07804 and 0.007 respectively.The flow instability domain is in temperature range of 1 050~1 125 ℃ and strain rate range of 0.1~0.3 s 1.The temperature of 1 150 ℃ and deformation rate of 0.1 s 1are the best hot deformation condition.