H13钢高温热变形特征与动态再结晶行为  

Hot deformation characteristics and dynamic recrystallization behavior of H13 steel at high temperature

作　　者：陈国鑫 桑宝光 刘宏伟[2] 高磊 高栋 CHEN Guo-xin;SANG Bao-guang;LIU Hong-wei;GAO Lei;GAO Dong(School of Mechanical Engineering and Automation,Dalian Polytechnic University,Dalian 116034,China;Shengyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]大连工业大学机械工程与自动化学院,辽宁大连116034 [2]中国科学院金属研究所沈阳材料科学国家研究中心,辽宁沈阳110016

出　　处：《塑性工程学报》2022年第6期193-202,共10页Journal of Plasticity Engineering

基　　金：辽宁省教育厅自然科学基础项目(J2020050)。

摘　　要：利用Gleeble-3800热模拟试验机在加热温度900~1150℃、应变速率0.01~10 s^(-1)下对H13钢进行了单道次热压缩实验,依据热压缩实验获得的真应力-真应变曲线构建了H13钢的高温本构方程、热加工图、动态再结晶动力学模型和动态再结晶晶粒尺寸模型,并结合微观组织研究了H13钢的动态再结晶行为。结果表明,在低温低应变速率时(900~950℃,0.01 s^(-1)),动态再结晶出现峰值应力点。在高温低应变速率时(1050~1150℃,0.01 s^(-1)),不存在明显的峰值应力,随着变形量的增加,出现了不同程度的二次硬化。温度较高时(1050℃),随着应变速率的增加,二次硬化效果显著。热变形激活能Q为419853.623 J·mol^(-1),最佳热加工工艺参数为温度1050~1150℃,应变速率0.1~1 s^(-1)。根据微观组织分析结果可知,在低温高应变速率下,晶粒为长条形,温度升高到1050℃后,再结晶体积分数增加,呈现出动态再结晶特征。而在高温低应变速率(1150℃,0.01 s^(-1))下,动态再结晶程度较高会使微观组织粗化,不利于材料的热加工成形。在变形温度为900~970℃、应变速率为0.1~10 s^(-1)和变形温度为970~1150℃、应变速率为1.3~10 s^(-1)时,H13钢易发生流变失稳,在变形温度为1050~1150℃、应变速率为0.1~1 s^(-1)时,H13钢发生完全再结晶,且晶粒组织细小均匀,应优先选择为再结晶区域。The single pass hot compression experiment of H13 steel was carried out at the heating temperature of 900-1150℃and the strain rate of 0.01-10 s^(-1) using Gleeble-3800 thermal simulator.According to the true stress-true strain curves obtained by hot compression experiment,the high temperature constitutive equation,hot processing map,dynamic recrystallization kinetics model and dynamic recrystallization grain size model of H13 steel were established,and the dynamic recrystallization behavior of H13 steel was studied by combining the microstructure.The results show that the peak stress point appears in dynamic recrystallization at low temperature and low strain rates(900-950℃,0.01 s^(-1)).There is no obvious peak stress at high temperature and low strain rate(1050-1150℃,0.01 s^(-1)),and with the increase of deformation amount,secondary hardening with different degrees appears.When the temperature is high(1050℃),the effect of the secondary hardening is significant with the increase of strain rate.The hot deformation activation energy Q is 419853.623 J·mol^(-1),the best hot processing technological parameters is the temperature of 1050-1150℃and the strain rate of 0.1-1 s^(-1).According to the microstructure analysis results,it is found that the grains are in the shape of long strips at low temperature and high strain rate.When the temperature increases to 1050℃,the recrystallization volume fraction increases,which shows dynamic recrystallization characteristics.However,at high temperature and low strain rate(1150℃,0.01 s^(-1)),high dynamic recrystallization degree can make the microstructures coarsen,which is not conducive to the hot processing forming of the material.Flow instability of H13 steel is easy to occur at the deformation temperature of 900-970℃,strain rate of 0.1-10 s^(-1) and at the deformation temperature of 970-1150℃,strain rate of 1.3-10 s^(-1).The complete recrystallization of H13 steel occurs and grain microstructure is fine and uniform at the deformation temperature of 1050-1150�

关 键 词：H13钢 本构方程 热加工图 微观组织 动态再结晶 

分 类 号：TG142.1[一般工业技术—材料科学与工程]