Si-Cr-Mo改进型H13热作模具钢热变形行为及有限元模拟

Thermal deformation behavior and finite element simulation on Si-Cr-Mo modified H13 hot work die steel

利用Gleeble-3800热模拟实验机,对自主研发的Si-Cr-Mo改进型H13热作模具钢——3Cr2Mo3钢进行热压缩实验,研究了其在变形温度为950~1200℃、应变速率为0.01~10 s^(-1)条件下的热变形行为。基于实验得到的真应力-真应变曲线,建立了Arrhenius型本构方程,并对其进行真应变补偿。由动态材料模型构建了3Cr2Mo3钢的热加工图,并得到了最佳热加工范围。利用有限元软件DEFORM和光学显微镜,研究了3Cr2Mo3钢在热变形过程中的温度场与微观组织的关系。结果表明:3Cr2Mo3钢的真应力受应变速率和变形温度的影响,且在低应变速率下(0.01 s^(-1))出现明显的动态软化特征,6次真应变补偿型本构方程的拟合精度高;实验条件范围内,3Cr2Mo3钢的最佳热加工范围为变形温度为1110~1200℃、应变速率为0.01~1 s^(-1);有限元软件DEFORM温度场结果显示,随着变形温度的升高和应变速率的降低,试样的心部与表面的温度场分布均匀,微观组织为均匀细小的动态再结晶晶粒。

Hot compression tests were conducted on the self-developed Si-Cr-Mo modified H13 hot work die steel-3Cr2Mo3 steel by thermal simulation testing machine Gleeble-3800,and the thermal deformation behavior was studied at the deformation temperatures of 950-1200 ℃ and the strain rates of 0.01-10 s^(-1).Then,based on the true stress-true strain curves obtained from the test,the Arrhenius type constitutive equation was established,and the true strain compensation was performed on it.Furthermore,the thermal processing map of 3Cr2Mo3 steel was constructed by the dynamic material model,and the optimal thermal processing range was obtained.Finally,the relationship between temperature field and microstructure of 3Cr2Mo3 steel during the thermal deformation process was studied by finite element software DEFORM and optical microscopy.The results show that the true stress of 3Cr2Mo3 steel is affected by the strain rate and the deformation temperature,there is an obvious dynamic softening characteristic at low strain rate(0.01 s^(-1)),and the sixth degree true strain compensation type constitutive equation has high fitting accuracy.Within the range of test conditions,the optimum thermal processing range of 3Cr2Mo3 steel is the deformation temperature of 1110-1200 ℃ and the train rate of 0.01-1 s^(-1).The temperature field results of finite element software DEFORM show that with the increasing of deformation temperature and the decreasing of strain rate,the temperature field distribution at the core and surface of specimen is uniform,and the microstructures are uniform and fine dynamic recrystallized grains.