摘要
使用Gleeble-1500D热模拟试验机对9Ni钢进行了热压缩变形实验,研究其在应变量为0.8、变形温度为800~1150℃、应变速率为0.1~5 s^(-1)下的热变形行为,并对不同热变形条件下实验样品的微观组织进行了系统研究。研究发现,针对不同的变形条件,真应力-真应变曲线中的流变应力随着变形温度的升高以及应变速率的降低而逐渐下降,应变速率在1150℃时对流变应力的影响比在800℃时更明显。通过引入Zener-Hollomon方程构建了9Ni钢的本构方程,并绘制了不同应变下9Ni钢的热加工图。通过计算得到9Ni钢的应变热激活能为295.601 kJ·mol^(-1)。结合变形后的微观组织分析获得9Ni钢的最佳热加工变形温度范围为900~1000℃、应变速率范围为1~1.5 s^(-1)以及变形温度为1000~1150℃、应变速率为0.1~5 s^(-1)。在该范围内发生了完全动态再结晶,功率耗散效率大于0.27,为9Ni钢的控轧控冷工艺参数制定及优化提供了参考。
Thermal compression deformation experiments on 9 Ni steel were performed by Gleeble-1500 D thermal simulation test machine.The thermal deformation behavior was studied with strain amount of 0.8,deformation temperature of 800-1150℃and strain rate of 0.1-5 s^(-1),and the microstructure of experimental samples under different thermal deformation conditions was systematically studied.It is found that the flow stress of true stress-true strain curves decreases gradually with the increase of deformation temperature and the decrease of strain rate under different deformation conditions.The effect of strain rate on flow stress is more obvious at 1150℃than that at 800℃.The constitutive equation of 9 Ni steel was constructed by introducing Zener-Hollomon equation and the hot processing map of 9 Ni steel with different strains was drawn.It is obtained by calculation that the strain thermal activation energy of 9 Ni steel is 295.601 kJ·mol^(-1).The optimal hot processing deformation temperature range of 900-1000℃,strain rate range of 1-1.5 s^(-1) and deformation temperature range of 1000-1150℃,strain rate range of 0.1-5 s^(-1) are obtained by analyzing the microstructure of 9 Ni steel after deformation.Fully dynamic recrystallization occurs in this range,and the power dissipation efficiency is greater than 0.27,which provides a reference for the formulation and optimization of rolling control and cooling control process parameters of 9 Ni steel.
作者
宋泽
乔志霞
赵倩
张海军
SONG Ze;QIAO Zhi-xia;ZHAO Qian;ZHANG Hai-jun(School of Mechanical Engineering,Tianjin University of Commerce,Tianjin 300134,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2022年第4期135-143,共9页
Journal of Plasticity Engineering
基金
国家自然科学基金面上资助项目(51974201)。
关键词
9NI钢
热变形行为
本构方程
热加工图
9Ni steel
thermal deformation behavior
constitutive equation
hot processing map
