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利用Gleeble-3800热模拟试验机,研究了Ni-Cr-Mo-B特厚板钢在900~1150℃、应变速率为0.01~10 s-1、试样工程应变量为70%的热压缩变形行为。基于实验数据,使用回归分析的方法建立了Ni-Cr-Mo-B钢的双曲正弦Arrhenius型本构方程。采用应变硬化速率与应力关系曲线、实验流变曲线准确的确定了表征动态再结晶行为的重要特征参数:临界应力/应变、峰值应力/应变和稳态应力/应变。结果表明:Ni-Cr-Mo-B钢的热变形激活能(Q)为351074 J·mol-1;随着变形温度升高及应变速率减小,即Zener-Hollomon参数(Z)减小,各特征参数减小,有利于动态再结晶发生;临界应力与峰值应力比为0.89,临界应变与峰值应变之比为0.44。此外,基于Z参数,确定了Ni-Cr-Mo-B钢动态再结晶特征参数的数学预测模型。
Using the Gleeble-3800 thermal simulator, the hot deformation of Ni-Cr-Mo-B ultra-heavy plate steel at 900 ~ 1150 ℃, strain rate of 0.01 ~ 10 s-1 and sample strain of 70% behavior. Based on the experimental data, a hyperbolic sine Arrhenius constitutive equation of Ni-Cr-Mo-B steel was established by regression analysis. Using the curves of strain hardening rate and stress, the experimental rheological curves accurately determine the important characteristic parameters that characterize the dynamic recrystallization behavior: critical stress / strain, peak stress / strain and steady stress / strain. The results show that the thermal deformation activation energy (Q) of Ni-Cr-Mo-B steel is 351074 J · mol-1. With the increase of deformation temperature and the decrease of strain rate, the Zener-Hollomon parameter (Z) The decrease of each characteristic parameter is in favor of dynamic recrystallization. The ratio of critical stress to peak stress is 0.89, and the ratio of critical strain to peak strain is 0.44. In addition, based on the Z parameter, the mathematical predictive model of the dynamic recrystallization parameters of Ni-Cr-Mo-B steel was determined.