17Cr2Ni2Mo齿轮用钢热变形动态再结晶行为

 为了探索材料热塑性变形工艺理论，针对热轧态17Cr2Ni2Mo齿轮用钢进行热力模拟试验，研究材料在应变速率=0.01～10 s-1、热变形温度t=1 050～1 150 ℃条件下的动态再结晶行为。结果表明，在较高应变速率下，应力在峰值后，出现动态回复或持续性动态再结晶软化，在较低应变速率下，应力呈现波浪多峰值状，出现多次动态再结晶软化。通过加工硬化率随应变变化曲线(θ ε)，确定了动态再结晶临界特征应变量εc，结合峰值应变量εp统计得到εc/εp比值为0.629～0.854，并可知当应变速率一定时，εc随着温度升高而减小，当温度一定时，εc随应变速率的增大而增大。同时建立了流变应力本构方程，数据验证平均相对误差为1.705%。最后建立了动态再结晶动力学模型。

Dynamic recrystallization behavior of steel for 17Cr2Ni2Mo gears

 The thermal simulation test was carried out on the steel of hot rolled 17Cr2Ni2Mo gears. The dynamic recrystallization behavior of the materials were studied at strain rate=0.01~10 s-1 and hot deformation temperature t=1 050～1 150 ℃，which can provide theoretical guidance for exploring thermoplastic deformation processes of materials. The results show that the flow stress appears as a dynamic recovery or a continuous dynamic recrystallization softening phenomenon after the peak value at a higher strain rate. The flow stress exhibits multiple peaks in the wave and multiple dynamic recrystallization softening occurs at lower strain rates. The dynamic recrystallization critical characteristic strain εc is determined by the work hardening rate with strain curve (θ ε)，and the εc/εp ratio is statistically between 0.629 and 0.854. It can be seen that εc becomes smaller as the temperature increases as the strain rate is constant. When the temperature is constant，εc becomes larger as the strain rate becomes larger. At the same time，the constitutive equation of flow stress is established，and the average relative error of data verification is 1.705%. Finally，a dynamic recrystallization kinetics model was established，which can provide a theoretical reference for the formulation of related thermal processing processes.