摘要
采用等温压缩实验研究了20Cr2Ni4A钢在变形温度为900~1100℃、应变速率为0.01~10 s^(-1)、真应变为0.8条件下的热变形行为和显微组织演变。真应力-应变曲线表明,流变应力随应变速率的增大和变形温度的降低而增大。在950~1100℃、0.01~0.10 s^(-1)变形条件下,流变曲线有明显峰值,软化效果明显。根据峰值应力建立了20Cr2Ni4A钢的本构方程,计算出变形激活能为489.24 kJ/mol。基于动态材料模型,构建0.8真应变下热加工图并结合显微组织得出:高应变率和低变形温度更容易导致流变不稳定。在低温和高应变速率下变形的组织主要是伸长的变形晶粒,在975~1030℃、0.07~0.20 s^(-1)变形条件下,动态再结晶完全,组织细小且均匀,有效改善了原始晶粒大小不均匀的现象。
Isothermal compression experiments were conducted to investigate the hot deformation behavior and microstructural evolution of 20Cr2Ni4A steel under deformation temperatures of 900-1100℃,strain rates of 0.01-10 s^(-1),and true strains of 0.8.The true stress-strain curves indicate an increase in flow stress with increasing strain rate and decreasing deformation temperature.Significant peaks are observed in the flow curves at deformation temperatures of 950-1100℃and strain rates of 0.01-0.10 s^(-1),demonstrating pronounced softening effects.The constitutive equation of the 20Cr2Ni4A steel was established based on the peak stress,and the deformation activation energy was calculated to be 489.24 kJ/mol.Utilizing a dynamic materials model,a processing map was constructed at a true strain of 0.8,revealing that high strain rates and low deformation temperatures were more likely to induce flow instability.Microstructural analysis shows that at low temperatures and high strain rates,the predominant deformation mechanism involves elongated deformed grains.Complete dynamic recrystallization occurs at deformation temperatures ranging from 975 to 1030℃and strain rates ranging from 0.07 to 0.20 s^(-1),resulting in a fine and homogeneous microstructure that effectively mitigates the unevenness in the initial grain size.
作者
范英琦
吴晓东
周少荣
王忠英
FAN Yingqi;WU Xiaodong;ZHOU Shaorong;WANG Zhongying(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,China;East China Branch of Central Iron and Steel Research Institute,Huai'an 223000,China)
出处
《热加工工艺》
北大核心
2026年第2期76-82,共7页
Hot Working Technology
基金
国家重点研发计划项目(2020YFB2008100)。
