工程科学学报，第41卷，第4期：470-478,2019年4月 Chinese Journal of Engineering,Vol.41,No.4:470-478,April 2019 DOI:10.13374/j.issn2095-9389.2019.04.007:http://journals.ustb.edu.cn 38MnB5热成形钢高温变形行为及本构方程 林 利2)，李宝顺”，朱国明，康永林”，刘仁东) 1)北京科技大学材料科学与工程学院，北京100083,2)鞍钢股份有限公司技术中心，鞍山114009 ☒通信作者，E-mail:zhuguoming(@usth.cdu.cn 摘要利用Gleeble--3500热模拟试验机对38MnB5热成形钢的高温变形行为进行研究，分别在650~950℃温度区间内，以 0.01、0.1、1和10s1的应变速率对其进行等温单向拉伸测试，并得到相应条件下的真应力-应变曲线.结果表明：38MB5热 成形钢流变应力随着变形温度的升高而减小，随着应变速率的增大而增大.当应变速率逐渐增加时，热变形时发生的动态回 复和动态再结晶效果并不显著，而当温度逐渐升高时，二者作用逐渐加强.考虑了温度、应变速率和应变的综合复杂影响，建 立38MB5热成形钢高温下的本构方程.此本构方程通过对流变应力、应变、应变速率等实验数据的回归分析，得到与变形温 度、应变速率和应变相关的材料参数多项式。计算结果与实验结果对比发现，通过本构方程所获得的计算值与试验值吻合 良好. 关键词热成形钢；流变行为；本构方程；Arrhenius模型；拉伸测试 分类号TG142.1 High-temperature deformation behavior and constitutive relationship of press-hardening steel 38MnB5 LIN Li'.2,IBao-shun》,ZHU Guo-ming》回，KANG Yong-?4im》,LIU Ren-dong2 1)School of Material Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)Ansteel Technology Center,Anshan 114009,China Corresponding author,E-mail:zhuguoming@ustb.edu.cn ABSTRACT With the rapid development of global economy,problems in energy production and environmental protection are becom- ing severe,and the automotive industry is under increasing pressure to reduce the weight of vehicles and improve crash performance. Due to the demand for reduced vehicle weight as well as improved safety and crashworthiness,hot-stamped components from ultra-high strength steels have been utilized for automobile manufacturing.Currently,the most widely used hot-stamped steel plate is 22MnB5.Its tensile strength is 1500 MPa and yield strength is 1200 MPa.In contrast,as the demands for steel strength have increased,the demand for high strength grades of steel has been quickly put on the production agenda.In recent years,a novel hot-stamped steel,38MnB5 has been developed,with a tensile strength exceeding 2000 MPa.The high temperature deformation behavior of 38MnB5 steel was in- vestigated by the Gleeble-3500 thermal-mechanical simulator.The isothermal uniaxial tensile tests of the steel were performed within deformation temperature range of 650-950 C under strain rates of 0.01,0.1,1,and 10s,and the typical true stress-strain curves of 38MnB5 at relative conditions were analyzed.The experimental results show that the flow stress rises with decreasing deformation temperature under the same strain rate,and with an increasing strain rate.When the strain rate gradually increased,dynamic recovery and dynamical recrystallization exhibited an apparent effect on the hot deformation process,while the inconspicuous impact receded with rising temperature.In consideration of the multiple influences on deformation temperature,strain rate and strain,a phenomenolog- ical,constitutive relationship was developed to depict the hot deformation process of 38MnB5.In the established equation,the material 收稿日期：201804-13 基金项目：国家自然科学基金资助项目(U1460101)工程科学学报，第 41 卷，第 4 期: 470--478，2019 年 4 月 Chinese Journal of Engineering，Vol． 41，No． 4: 470--478，April 2019 DOI: 10． 13374 /j． issn2095--9389． 2019． 04． 007; http: / /journals． ustb． edu． cn 38MnB5 热成形钢高温变形行为及本构方程 林 利1，2) ，李宝顺1) ，朱国明1) ，康永林1) ，刘仁东2) 1) 北京科技大学材料科学与工程学院，北京 100083 2) 鞍钢股份有限公司技术中心，鞍山 114009 通信作者，E-mail: zhuguoming@ ustb． edu． cn 摘 要 利用 Gleeble--3500 热模拟试验机对 38MnB5 热成形钢的高温变形行为进行研究，分别在 650 ～ 950 ℃ 温度区间内，以 0. 01、0. 1、1 和 10 s － 1的应变速率对其进行等温单向拉伸测试，并得到相应条件下的真应力--应变曲线． 结果表明: 38MnB5 热 成形钢流变应力随着变形温度的升高而减小，随着应变速率的增大而增大． 当应变速率逐渐增加时，热变形时发生的动态回 复和动态再结晶效果并不显著，而当温度逐渐升高时，二者作用逐渐加强． 考虑了温度、应变速率和应变的综合复杂影响，建 立 38MnB5 热成形钢高温下的本构方程． 此本构方程通过对流变应力、应变、应变速率等实验数据的回归分析，得到与变形温 度、应变速率和应变相关的材料参数多项式． 计算结果与实验结果对比发现，通过本构方程所获得的计算值与试验值吻合 良好． 关键词 热成形钢; 流变行为; 本构方程; Arrhenius 模型; 拉伸测试 分类号 TG142. 1 收稿日期: 2018--04--13 基金项目: 国家自然科学基金资助项目( U1460101) High-temperature deformation behavior and constitutive relationship of press-hardening steel 38MnB5 LIN Li1，2) ，LI Bao-shun1) ，ZHU Guo-ming1)  ，KANG Yong-lin1) ，LIU Ｒen-dong2) 1) School of Material Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) Ansteel Technology Center，Anshan 114009，China Corresponding author，E-mail: zhuguoming@ ustb． edu． cn ABSTＲACT With the rapid development of global economy，problems in energy production and environmental protection are becom￾ing severe，and the automotive industry is under increasing pressure to reduce the weight of vehicles and improve crash performance． Due to the demand for reduced vehicle weight as well as improved safety and crashworthiness，hot-stamped components from ultra-high strength steels have been utilized for automobile manufacturing． Currently，the most widely used hot-stamped steel plate is 22MnB5． Its tensile strength is 1500 MPa and yield strength is 1200 MPa． In contrast，as the demands for steel strength have increased，the demand for high strength grades of steel has been quickly put on the production agenda． In recent years，a novel hot-stamped steel，38MnB5 has been developed，with a tensile strength exceeding 2000 MPa． The high temperature deformation behavior of 38MnB5 steel was in￾vestigated by the Gleeble--3500 thermal-mechanical simulator． The isothermal uniaxial tensile tests of the steel were performed within deformation temperature range of 650--950 ℃ under strain rates of 0. 01，0. 1，1，and 10 s － 1，and the typical true stress-strain curves of 38MnB5 at relative conditions were analyzed． The experimental results show that the flow stress rises with decreasing deformation temperature under the same strain rate，and with an increasing strain rate． When the strain rate gradually increased，dynamic recovery and dynamical recrystallization exhibited an apparent effect on the hot deformation process，while the inconspicuous impact receded with rising temperature． In consideration of the multiple influences on deformation temperature，strain rate and strain，a phenomenolog￾ical，constitutive relationship was developed to depict the hot deformation process of 38MnB5． In the established equation，the material