D0L:10.13374/.issn1001-053x.2011.07.010 第33卷第7期 北京科技大学学报 Vol.33 No.7 2011年7月 Journal of University of Science and Technology Beijing Jul.2011 两阶段控制冷却工艺对含钼X80抗大变形管线钢组 织与性能的影响 孟德亮) 康永林)四郑晓飞) 安守勇”夏佃秀) 1)北京科技大学材料科学与工程学院，北京1000832)济南钢铁集团总公司技术中心，济南250101 ☒通信作者，E-mail:kangylin@usth.edu.cn 摘要采用TMCP热轧及轧后两阶段控制冷却技术，在试验室制备了含Mo成分的X80级抗大变形管线钢，并利用扫描电 镜和透射电镜等分析方法研究了不同冷却条件对组织与性能的影响.结果表明，采用两阶段控制冷却工艺的含Mo成分X80 抗大变形管线钢为铁素体一贝氏体双相组织：随加速冷却中开冷温度降低，组织中铁素体含量增加，试样强度降低，屈强比降 低，均匀伸长率提高：随加速冷却中终冷温度降低，贝氏体中M/A含量减少，尺寸更细小，分布更分散，试样强度变化不大但均 匀伸长率显著提升.分析表明，当铁素体含量一定时，均匀伸长率与贝氏体中M/A密切相关，细小且均匀分布的M/A可提高 加工硬化速率，推迟颈缩发生，使均匀伸长率升高.当加速冷却中开冷温度为690℃、终冷温度为450℃时，组织中铁素体的体 积分数约为23%、晶粒尺寸约为5μm,M/A岛尺寸约为1μm,组织均匀性良好，试样得到最优的强度塑性匹配. 关键词管线钢：钼：控制冷却：微观组织：力学性能 分类号TG142.4:TG335.1 Effect of two-stage controlled cooling on the microstructure and properties of Mo-containing X80 high-deformability pipeline steel MENG De-liang,KANG Yong-lin,ZHENG Xiao-fei,AN Shou-yong?,XIA Dian-xiu) 1)School of Materials Science and Engineering.University of Science and Technology Beijing,Beijing 100083,China 2)Technology Center,Jinan Iron Steel Co.Ltd.,Jinan 250101,China Corresponding author,E-mail:kangylin@ustb.edu.cn ABSTRACT A Mo-eontaining X80 high-deformability pipeline steel was processed by TMCP rolling and two-stage controlled cooling in laboratory.The effects of cooling conditions on the microstructure and properties of the steel were investigated by scanning electron microscopy (SEM)and transmission electron microscopy (TEM).It is found that the microstructure of the steel processed by two-stage controlled cooling is ferrite-bainite dual phase.As the start temperature in accelerated cooling comes down,both the strength and yield ratio decrease and the uniform elongation (uEl)increases with the ferritic volume fraction increasing.As the finish temperature in accelerated cooling becomes lower,the amount of martensite-austenite (M/A)constituents in bainite decreases and the M/A islands are much finer and more uniformly dispersed.The strength changes little but the uEl increases significantly.It is considered that uEl is closely related to M/A constituents in bainite when the ferritic volume fraction is constant.Finely and uniformly dispersed M/A islands can increase the value of uEl by increasing the work hardening rate and delaying the onset of necking.When the accelerated cooling starts at 690C and finishes at 450C,the ferritic volume fraction is about 23%,the grain size is approximately 5um,and the average grain size of M/A islands is approximately 1 um.The uniform microstructure provides good combination of strength-ductility properties. KEY WORDS pipeline steel;molybdenum:controlled cooling:microstructure:mechanical properties 长距离油气输送管线在敷设和服役过程中，不 黄土区等地质活动复杂的地带，在地质作用下管道 可避免地会穿越地震多发区、不连续冻土区和疏松 会因外部非正常载荷干扰而产生屈曲、拉裂和挤毁 收稿日期：20100709 基金项目：国家高技术研究发展计划资助项目(No.2009AA03Z518)第 33 卷 第 7 期 2011 年 7 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 33 No． 7 Jul． 2011 两阶段控制冷却工艺对含钼 X80 抗大变形管线钢组 织与性能的影响 孟德亮1) 康永林1)  郑晓飞1) 安守勇2) 夏佃秀2) 1) 北京科技大学材料科学与工程学院，北京 100083 2) 济南钢铁集团总公司技术中心，济南 250101  通信作者，E-mail: kangylin@ ustb． edu． cn 摘 要 采用 TMCP 热轧及轧后两阶段控制冷却技术，在试验室制备了含 Mo 成分的 X80 级抗大变形管线钢，并利用扫描电 镜和透射电镜等分析方法研究了不同冷却条件对组织与性能的影响． 结果表明，采用两阶段控制冷却工艺的含 Mo 成分 X80 抗大变形管线钢为铁素体 － 贝氏体双相组织; 随加速冷却中开冷温度降低，组织中铁素体含量增加，试样强度降低，屈强比降 低，均匀伸长率提高; 随加速冷却中终冷温度降低，贝氏体中 M/A 含量减少，尺寸更细小，分布更分散，试样强度变化不大但均 匀伸长率显著提升． 分析表明，当铁素体含量一定时，均匀伸长率与贝氏体中 M/A 密切相关，细小且均匀分布的 M/A 可提高 加工硬化速率，推迟颈缩发生，使均匀伸长率升高． 当加速冷却中开冷温度为 690 ℃、终冷温度为 450 ℃时，组织中铁素体的体 积分数约为 23% 、晶粒尺寸约为 5 μm，M/A 岛尺寸约为 1 μm，组织均匀性良好，试样得到最优的强度塑性匹配． 关键词 管线钢; 钼; 控制冷却; 微观组织; 力学性能 分类号 TG142. 4; TG335. 1 Effect of two-stage controlled cooling on the microstructure and properties of Mo-containing X80 high-deformability pipeline steel MENG De-liang1) ，KANG Yong-lin1)  ，ZHENG Xiao-fei 1) ，AN Shou-yong2) ，XIA Dian-xiu2) 1) School of Materials Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) Technology Center，Jinan Iron ＆ Steel Co． Ltd． ，Jinan 250101，China  Corresponding author，E-mail: kangylin@ ustb． edu． cn ABSTRACT A Mo-containing X80 high-deformability pipeline steel was processed by TMCP rolling and two-stage controlled cooling in laboratory． The effects of cooling conditions on the microstructure and properties of the steel were investigated by scanning electron microscopy ( SEM) and transmission electron microscopy ( TEM) ． It is found that the microstructure of the steel processed by two-stage controlled cooling is ferrite-bainite dual phase． As the start temperature in accelerated cooling comes down，both the strength and yield ratio decrease and the uniform elongation ( uEl) increases with the ferritic volume fraction increasing． As the finish temperature in accelerated cooling becomes lower，the amount of martensite-austenite ( M/A) constituents in bainite decreases and the M/A islands are much finer and more uniformly dispersed． The strength changes little but the uEl increases significantly． It is considered that uEl is closely related to M/A constituents in bainite when the ferritic volume fraction is constant． Finely and uniformly dispersed M/A islands can increase the value of uEl by increasing the work hardening rate and delaying the onset of necking． When the accelerated cooling starts at 690 ℃ and finishes at 450 ℃，the ferritic volume fraction is about 23% ，the grain size is approximately 5 μm，and the average grain size of M/A islands is approximately 1 μm． The uniform microstructure provides good combination of strength-ductility properties． KEY WORDS pipeline steel; molybdenum; controlled cooling; microstructure; mechanical properties 收稿日期: 2010--07--09 基金项目: 国家高技术研究发展计划资助项目( No． 2009AA03Z518) 长距离油气输送管线在敷设和服役过程中，不 可避免地会穿越地震多发区、不连续冻土区和疏松 黄土区等地质活动复杂的地带，在地质作用下管道 会因外部非正常载荷干扰而产生屈曲、拉裂和挤毁 DOI:10.13374/j.issn1001-053x.2011.07.010