D0I:10.13374f.issn1001-053x.2012.03.010 第34卷第3期 北京科技大学学报 Vol.34 No.3 2012年3月 Journal of University of Science and Technology Beijing Mar.2012 T91钢的高温塑性变形及动态再结晶行为 陈振湘) 许晓嫦)四王斌》石绍清》 张金菊” 王福晶” 1)中南大学材料科学与工程学院，长沙4100832)华菱衡钢钢管研究院，长沙410083 ☒通信作者，Email:c12@126.com 摘要采用Gleeble--1500热模拟试验机进行了T91钢的压缩试验，研究了变形温度为1100-1250℃、应变速率为0.01~ 1s时该钢的变形行为，分析了流变应力与应变速率和变形温度之间的关系，计算了高温变形时应力指数和变形激活能，并 采用Zener--Hollomon参数法构建该钢高温塑性变形的本构关系，绘制了动态再结晶图和热加工图.结果表明：在试验变形条 件范围内，其真应力一真应变曲线呈双峰特征：钢中发生了明显的动态再结晶，且再结晶类型属于连续动态再结晶.四1钢的 热变形激活能为484kJ·ol1,利用加工图确定了热变形的流变失稳区，结合力学性能，可以优先选择的变形温度为1200~ 1250℃，应变速率不高于0.1s 关键词耐热钢：塑性变形：本构方程：动态再结晶 分类号TG111.7 Plastic deformation and dynamic recrystallization of T91 steel at high tempera- ture CHEN Zhen-xiang',XU Xiao--chang'回，WANG Bin'',SHI Shao--ing，ZHANG Jin-ju”，WANG Fu-jing'” 1)College of Materials Science and Engineering.Central South University,Changsha 410083.China 2)Research Institute for Hengyang Valin Steel Tube Plant,Changsha 410083,China Corresponding author,E-mail:xxc12@126.com ABSTRACT Hot compressive tests were carried out on a Gleeble-1500 thermal simulation test machine to investigate the hot deform- ation behavior of T91 steel at elevated temperatures of 1100 to 1250C and strain rates of 0.01 to 1s.The relations of flow stress to strain rate and deformation temperature were analyzed for calculating the stress exponent and the deformation activation energy at the elevated temperatures.The constitutive equation was constructed by introducing the Zener-Hollomon parameter.The dynamic recrystal- lization map and the processing map of plastic deformation of T91 steel at the elevated temperatures were drawn.The true stress-strain curves of the steel show a bimodal characteristic.Distinct dynamic recrystallization takes place in the steel,and its mechanism is continuous dynamic recrystallization.The deformation activation energy of the steel is 484kJmol.The instability zones and optimum processing parameters of hot deformation under the condition can be attained by using the two maps.The steel has excellent mechanical properties when rolled at deformation temperatures of 1200 to 1250C and strain rates which are not greater than 0.1s KEY WORDS heat resistant steel;plastic deformation:constitutive equations:dynamic recrystallization T91(9Cr-1Mo-V-Nb)钢是在9Cr-1Mo型耐热 形温区窄，这使得91钢的工业生产具有一定的 钢基础上，添加V、Nb和N等元素开发的新型耐热 难度ǖ-0 钢.该钢种因其高的热强性，良好的持久塑性、抗氧 91钢的热变形行为是制定其轧制、穿孔等热 化性和抗腐蚀性能，低的热膨胀系数和较低的生产 加工工艺的理论依据，其主要受变形温度、变形速率 成本被广泛用于超临界锅炉耐热管道.但是，T91 和变形程度的影响.Tamura等研究了650℃时，T91 钢为低碳高合金钢，其化学成分复杂，属于难变形钢 钢中MX型碳氮化物对其蠕变性能的影响；宁保 种，在热变形过程中变形抗力大、塑性低以及适宜变 群则对四1钢相变过程及强化工艺进行了研究圆： 收稿日期：2011-04-13第 34 卷 第 3 期 2012 年 3 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 34 No． 3 Mar． 2012 T91 钢的高温塑性变形及动态再结晶行为 陈振湘1) 许晓嫦1) 王 斌1) 石绍清2) 张金菊1) 王福晶1) 1) 中南大学材料科学与工程学院，长沙 410083 2) 华菱衡钢钢管研究院，长沙 410083 通信作者，E-mail: xxc12@ 126． com 摘 要 采用 Gleeble--1500 热模拟试验机进行了 T91 钢的压缩试验，研究了变形温度为 1 100 ～ 1 250 ℃、应变速率为0. 01 ～ 1 s － 1 时该钢的变形行为，分析了流变应力与应变速率和变形温度之间的关系，计算了高温变形时应力指数和变形激活能，并 采用 Zener--Hollomon 参数法构建该钢高温塑性变形的本构关系，绘制了动态再结晶图和热加工图． 结果表明: 在试验变形条 件范围内，其真应力--真应变曲线呈双峰特征; 钢中发生了明显的动态再结晶，且再结晶类型属于连续动态再结晶． T91 钢的 热变形激活能为 484 kJ·mol － 1 ，利用加工图确定了热变形的流变失稳区，结合力学性能，可以优先选择的变形温度为1 200 ～ 1 250 ℃，应变速率不高于 0. 1 s － 1 ． 关键词 耐热钢; 塑性变形; 本构方程; 动态再结晶 分类号 TG111. 7 Plastic deformation and dynamic recrystallization of T91 steel at high tempera￾ture CHEN Zhen-xiang1) ，XU Xiao-chang1) ，WANG Bin1) ，SHI Shao-qing2) ，ZHANG Jin-ju1) ，WANG Fu-jing1) 1) College of Materials Science and Engineering，Central South University，Changsha 410083，China 2) Research Institute for Hengyang Valin Steel Tube Plant，Changsha 410083，China Corresponding author，E-mail: xxc12@ 126． com ABSTRACT Hot compressive tests were carried out on a Gleeble-1500 thermal simulation test machine to investigate the hot deform￾ation behavior of T91 steel at elevated temperatures of 1 100 to 1 250 ℃ and strain rates of 0. 01 to 1 s － 1 ． The relations of flow stress to strain rate and deformation temperature were analyzed for calculating the stress exponent and the deformation activation energy at the elevated temperatures． The constitutive equation was constructed by introducing the Zener-Hollomon parameter． The dynamic recrystal￾lization map and the processing map of plastic deformation of T91 steel at the elevated temperatures were drawn． The true stress-strain curves of the steel show a bimodal characteristic． Distinct dynamic recrystallization takes place in the steel，and its mechanism is continuous dynamic recrystallization． The deformation activation energy of the steel is 484 kJ·mol － 1 ． The instability zones and optimum processing parameters of hot deformation under the condition can be attained by using the two maps． The steel has excellent mechanical properties when rolled at deformation temperatures of 1 200 to 1 250 ℃ and strain rates which are not greater than 0. 1 s － 1 ． KEY WORDS heat resistant steel; plastic deformation; constitutive equations; dynamic recrystallization 收稿日期: 2011--04--13 T91( 9Cr--1Mo--V--Nb) 钢是在 9Cr--1Mo 型耐热 钢基础上，添加 V、Nb 和 N 等元素开发的新型耐热 钢． 该钢种因其高的热强性，良好的持久塑性、抗氧 化性和抗腐蚀性能，低的热膨胀系数和较低的生产 成本被广泛用于超临界锅炉耐热管道． 但是，T91 钢为低碳高合金钢，其化学成分复杂，属于难变形钢 种，在热变形过程中变形抗力大、塑性低以及适宜变 形温区窄，这使得 T91 钢的工业生产具有一定的 难度［1--4］． T91 钢的热变形行为是制定其轧制、穿孔等热 加工工艺的理论依据，其主要受变形温度、变形速率 和变形程度的影响． Tamura 等研究了 650 ℃ 时，T91 钢中 MX 型碳氮化物对其蠕变性能的影响［5］; 宁保 群则对 T91 钢相变过程及强化工艺进行了研究［6］; DOI:10.13374/j.issn1001-053x.2012.03.010