【摘要】 目的基于实测的流动应力曲线,构建可用于热成形模拟的34Cr2Ni2Mo合金结构钢高精度本构方程。方法采用热模拟试验测试该材料的流动应力曲线,在动态再结晶的条件下,构建了基于物理机制的热本构方程,通过曲线拟合获得了本构方程参数。结果热模拟试验测试的流动应力曲线具有明显的动态再结晶现象,构建的本构方程包括流动应力、屈服/饱和/临界/稳态应力、发生50%再结晶的时间等内变量计算方程,在参数拟合后对其误差分析表明,本构方程计算的流动应力偏差控制在±15 MPa以内。结论 34Cr2Ni2Mo合金结构钢本构方程能够较为准确的描述该钢在热成形过程的流动应力变化特征,具有较强的数值稳定性和外延拓展性。更多还原

【Abstract】 The work aims to build the high-precision constitutive equation of 34Cr2Ni2Mo alloy structural steel used to simulate thermal forming based on the measured flow stress curves. The flow stress curves of the material were tested through the thermal simulation. The hot constitutive equation was built based on the physical mechanism under the conditions of dynamic recrystallization. The parameters of constitutive equation were obtained through curve fitting. The flow stress curves of the material tested through thermal simulation had obvious dynamic recrystallization. The constitutive equation included equations of internal variables, such as flow stress, yield/saturated/critical/steady stress and the time for occurrence of 50% recrystallization. After parameter fitting, the error analysis indicated that the flow stress deviation calculated by the constitutive equation should be controlled within ±15 MPa. The constitutive equation of 34Cr2Ni2Mo alloy structural steel can describe the change features of flow stress in the of forming process of the steel in a relatively correct manner, which is of good numerical stability and extensionality.更多还原