D0L:10.13374h.issn1001-053x.2013.11.013 第35卷第11期 北京科技大学学报 Vol.35 No.11 2013年11月 Journal of University of Science and Technology Beijing Nov.2013 700℃超超临界锅炉材料GH4700合金热压缩行为 王珏)凶，董建新1)，张麦仓1)，谢锡善)，徐芳泓2) 1)北京科技大学材料科学与工程学院，北京100083 2)太原钢铁集团有限公司先进不锈钢材料国家重点实验室，太原030003 ☒通信作者，E-mail:wangjue sor@126.com 摘要利用变形温度为1120~1210℃、应变速率为0.1~20s-1以及变形量为15%~60%的等温热压缩实验研究了 GH4700合金的热变形行为.通过对低温和高应变速率条件下的形变热效应进行修正，得到准确的流变曲线，推导出描 述峰值应力与温度和应变速率等变形参数的本构方程，并得到GH4700合金热变形表观激活能为322kJ.组织分析表 明，动态再结晶是热变形过程中最主要的软化方式，再结晶形核方式为应变诱发晶界迁移，变形温度升高和应变速率增 大均有利于再结晶形核.再结晶发展阶段，随着变形量的增大和变形温度的升高，动态再结晶比例增加，在应变速率· 温度坐标中，再结晶比例等值线呈反“C”形式.采用分段函数描述了不同应变速率下GH4700合金动态再结晶晶粒尺 寸与变形参数的关系. 关键词镍合金：热压缩：动态再结晶：形变热效应 分类号TG146.1+5 Deformation behaviors during hot compression of GH4700 alloy for 700 C ultra-supercritical boilers WANG Jue),DONG Jian-rin),ZHANG Mai-cang),XIE Xi-shan),XU Fang-hong2) 1)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)State Key Laboratory of Advanced Stainless Steel Materials,Taiyuan Iron Steel (Group)Co.Ltd.,Taiyuan 030003,China Corresponding author,E-mail:wangjue.sor@126.com ABSTRACT The hot deformation behavior of nickel-based superalloy GH4700 was investigated by isothermal com- pression tests at temperatures of 1120 to 1210C and strain rates of 0.1 to 20 s-1 with deformations of 15%to 60%.The flow curves at high strain rate and low temperature were corrected in consideration of the deformation-heating effect. Accurate constitutive equations were established between peak stress and deformation parameters,i.e.,temperature and strain rate.The activation energy of the alloy was determined to be 322 kJ.Microstructure analysis results show that dynamic recrystallization (DRX)is the principal softening mechanism during hot working.Strain-induced-grain- boundary-migration is the nucleation mechanism,which is promoted by the increase of both temperature and strain rate. The ratio of DRX grains is increased by temperature and strain,while the iso-ratio contour of DRX exhibits an "anti- C"type in the strain rate-temperature coordinate system.The relationship between DRX grain size and deformation parameters was calculated to be a piecewise function which depends on strain rate. KEY WORDS nickel alloys:hot compression;dynamic recrystallization;deformation heating 作为700℃以上超超临界锅炉管道的备选材料 满足超超临界条件的要求，GH4700设计中加入大 之一，GH4700合金热变形行为和加工性是其应用量合金元素：25%Cr使合金具有耐高温氧化和硫酸 的保证，也是国产化前需要解决的重要问题.为了 盐腐蚀的能力)：20%Co作为基体组成元素可以增 收稿日期：2012-10-22 基金项目：国家自然科学基金资助项目(50831008)第 35 卷 第 11 期 北 京 科 技 大 学 学 报 Vol. 35 No. 11 2013 年 11 月 Journal of University of Science and Technology Beijing Nov. 2013 700 ℃超超临界锅炉材料 GH4700 合金热压缩行为 王 珏1) ，董建新1)，张麦仓1)，谢锡善1)，徐芳泓2) 1) 北京科技大学材料科学与工程学院，北京 100083 2) 太原钢铁集团有限公司先进不锈钢材料国家重点实验室，太原 030003 通信作者，E-mail: wangjue sor@126.com 摘 要 利用变形温度为 1120∼1210 ℃、应变速率为 0.1∼20 s−1 以及变形量为 15%∼60%的等温热压缩实验研究了 GH4700 合金的热变形行为. 通过对低温和高应变速率条件下的形变热效应进行修正，得到准确的流变曲线，推导出描 述峰值应力与温度和应变速率等变形参数的本构方程，并得到 GH4700 合金热变形表观激活能为 322 kJ. 组织分析表 明，动态再结晶是热变形过程中最主要的软化方式，再结晶形核方式为应变诱发晶界迁移，变形温度升高和应变速率增 大均有利于再结晶形核. 再结晶发展阶段，随着变形量的增大和变形温度的升高，动态再结晶比例增加，在应变速率 - 温度坐标中，再结晶比例等值线呈反 “C” 形式. 采用分段函数描述了不同应变速率下 GH4700 合金动态再结晶晶粒尺 寸与变形参数的关系. 关键词 镍合金；热压缩；动态再结晶；形变热效应 分类号 TG146.1+5 Deformation behaviors during hot compression of GH4700 alloy for 700 ℃ ultra-supercritical boilers WANG Jue1) , DONG Jian-xin1), ZHANG Mai-cang1), XIE Xi-shan1), XU Fang-hong2) 1) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 2) State Key Laboratory of Advanced Stainless Steel Materials, Taiyuan Iron & Steel (Group) Co. Ltd., Taiyuan 030003, China Corresponding author, E-mail: wangjue sor@126.com ABSTRACT The hot deformation behavior of nickel-based superalloy GH4700 was investigated by isothermal com￾pression tests at temperatures of 1120 to 1210 ℃ and strain rates of 0.1 to 20 s−1 with deformations of 15% to 60%. The flow curves at high strain rate and low temperature were corrected in consideration of the deformation-heating effect. Accurate constitutive equations were established between peak stress and deformation parameters, i.e., temperature and strain rate. The activation energy of the alloy was determined to be 322 kJ. Microstructure analysis results show that dynamic recrystallization (DRX) is the principal softening mechanism during hot working. Strain-induced-grain￾boundary-migration is the nucleation mechanism, which is promoted by the increase of both temperature and strain rate. The ratio of DRX grains is increased by temperature and strain, while the iso-ratio contour of DRX exhibits an “anti￾C” type in the strain rate-temperature coordinate system. The relationship between DRX grain size and deformation parameters was calculated to be a piecewise function which depends on strain rate. KEY WORDS nickel alloys; hot compression; dynamic recrystallization; deformation heating 作为 700 ℃以上超超临界锅炉管道的备选材料 之一，GH4700 合金热变形行为和加工性是其应用 的保证，也是国产化前需要解决的重要问题. 为了 满足超超临界条件的要求，GH4700 设计中加入大 量合金元素：25% Cr 使合金具有耐高温氧化和硫酸 盐腐蚀的能力 [1]；20% Co 作为基体组成元素可以增 收稿日期：2012-10-22 基金项目：国家自然科学基金资助项目 (50831008) DOI:10.13374/j.issn1001-053x.2013.11.013