基于摩擦修正的GE1014钢热本构方程及热加工图

Thermal constitutive equation and thermal processing map on GE1014 steel based on friction correction

对GE1014钢进行了热变形温度为850~1200℃、应变速率为0.01~10 s^(-1)、应变量为0.7条件下的高温轴向压缩试验,对流变曲线进行了摩擦修正,建立了GE1014钢的热本构方程和Z参数方程,基于动态材料模型理论建立了GE1014钢的热加工图,并通过材料变形后的显微组织分析确定了热加工图的准确性和最后热变形区域。结果表明,摩擦效应在低变形温度或高应变速率条件下对GE1014钢的高温流变曲线影响显著;计算得到摩擦修正后的GE1014钢的热变形激活能为400.197 kJ·mol^(-1);当试验钢的真应变为0.4和0.7时,在试验条件下的高温、低应变速率区的能量耗散效率η达到最大值0.34。综合分析热加工图及试验钢的显微组织,确定了GE1014钢在变形温度为1100~1150℃、应变速率为0.1 s^(-1)条件下能够获得均匀、细小的完全动态再结晶组织,此时GE1014钢的热加工性能最好。

The high temperature axial compression test was conducted on GE1014 steel under the conditions of the thermal deformation temperature of 850-1250℃,the strain rate of 0.01-10 s^(-1) and the deformation amount of 0.7,and the rheological curves were modified by friction correction.Then,the thermal constitutive equation and Z parameter formula of GE1014 steel were established,and the thermal processing map of GE1014 steel was established based on the theory of dynamic material model.Finally,the accuracy of thermal processing map and the optimum thermal deformation zone were confirmed by analyzing the microstructure of the material after deformation.The results show that friction effect significantly affects the high temperature rheological curve of GE1014 steel at low deformation temperature or high strain rate,and the thermal deformation activation energy of GE1014 steel after fiction correction is calculated as 400.197 kJ·mol^(-1).When the true strain of the test steel is 0.4 and 0.7 respectively,the maximum energy dissipation efficiencyηunder the high temperature and low strain rate reaches the maximum of 0.34.Comprehensively analyzing the thermal processing map and the microstructure of the test steel,it is determined that the GE1014 steel under the deformation temperature of 1100-1150℃and the strain rate of 0.1 s^(-1) can obtain the uniform and fine fully dynamically recrystallized structure,and the thermal workability of GE1014 steel is the best at this time.