Experimental on process, microstructure and mechanical properties of X80 high strength pipeline steel for low temperature
DUAN He1,2, SHAN Yi-yin1, YANG Ke1, SHI Xian-bo1, YAN Wei1, REN Yi3
1. Institute of Metal Research, Chinese Academy of Science, Shenyang 110016, Liaoning, China; 2. School ofMaterials Science and Engineering, University of Science and Technology of China, Hefei 230000, Anhui, China; 3. State Key Laboratory of Metal Materials and Application for Marine Equipment, Anshan 114009, Liaoning, China
Abstract：As the pipeline extends to low temperature areas,higher requirements are imposed on the low temperature performance of the pipeline. In order to break through the bottleneck of the strength and toughness balance of high strength pipeline steel laid in the low-temperature region,it is necessary to optimize the microstructure and the thermal mechanical controlled process (TMCP) of the commercial available pipeline steel. In order to study the relationship between the TMCP parameters and the complex microstructure to guide the actual rolling process,the Gleeble thermal simulator was used to observe the different microstructures by changing the cooling rate,finishing rolling temperature,finishing cooling temperature and relaxed time,and then,the change rule in the different microstructures was analyzed. The results showed that with increase of the cooling rate,the volume percent of polygonal (quasi-polygonal) ferrite decreased but that of the bainitic ferrite increased. With increase of the finishing rolling temperature,the grains were coarsening but the fraction of acicular ferrite was basically unchanged. When the finishing cooling temperature was raised to 550 ℃,severely coarsened microstructure was emerged and a large number of MA islands with sharp-angled shape which are harmful to the low temperature toughness appeared. When the relaxed time was prolonged,the grain size and the volume percent of polygonal ferrite were both gradually increased. Based on the results on properties,a microstructure composed of fine quasi-polygonal ferrite (PF),granular bainite (GB) and a small amount of bainitic ferrite (BF) (QF+GB accounted for more than 90%) was designed for the X80 pipeline steel used in extremely-cold region. In this microstructure,the percentage of high angle grain boundaries was more than 50%. Finally,the industrial TMCP parameters such as finishing rolling temperature,finishing cooling temperature and cooling rate were optimized to be 750 ℃,480 ℃ and 20 ℃/s,respectively,which made the X80 pipeline steel with excellent low temperature impact toughness,satisfying the requirements of comprehensive properties,especially in the extremely-cold region.
段贺, 单以银, 杨柯, 史显波, 严伟, 任毅. X80低温用高强度管线钢的工艺与组织性能试验[J]. 钢铁, 2020, 55(2): 103-111.
DUAN He, SHAN Yi-yin, YANG Ke, SHI Xian-bo, YAN Wei, REN Yi. Experimental on process, microstructure and mechanical properties of X80 high strength pipeline steel for low temperature. Iron and Steel, 2020, 55(2): 103-111.
[1] 张彩军,蔡开科,袁伟霞,等. 管线钢的性能要求与炼钢生产特点[J]. 炼钢,2002,18(5):40.(ZHANG Cai-jun,CAI Kai-ke,YUAN Wei-xia,et al. Performance requirements and productive feature of pipeline steel[J]. Steelmaking,2002,18(5):40.) [2] 程政,缪成亮,王章岭,等. X80管线钢边部裂纹成因分析与改进[J]. 中国冶金,2019,29(8):76. (CHENG Zheng,MIAO Cheng-liang,WANG Zhang-ling,et al. Formation analysis and improvement of edge cracks in X80 pipeline steel[J]. China Metallurgy,2019,29(8):76.) [3] 陈妍,牟昊,丁伟. 国内外管线钢最新研发进展[J]. 轧钢,2012,29(2):37.(CHEN Yan,MU Hao,DING Wei. R&D progress on technology for producing pipeline steel at home and aboard[J]. Steel Rolling,2012,29(2):37.) [4] Coldren A P,Mihelich J L. Acicular ferrite HSLA steels for line pipe[J]. Metal Science and Heat Treatment,1977,19(7):559. [5] 朱立光,王雁,王硕明,等. 微合金元素钒和铌对诱发针状铁素体的影响[J]. 钢铁,2019,54(8):216. (ZHU Li-guang,WANG Yan,WANG Shuo-ming,et al. Effect of microalloy elements V and Nb on induction of intragranular acicular ferrite[J]. Iron and Steel,2019,54(8):216.) [6] 赵晶军,龙木军,汪勤政,等. 不同冷速下钛微合金化Q345B钢的HAZ组织及性能[J]. 中国冶金,2019,29(3):11.(ZHAO Jing-jun,LONG Mu-jun,WANG Qin-zheng,et al. Microstructure and properties of titanium microalloyed Q345B steel in heat affected zone at different cooling rates[J]. China Metallurgy,2019,29(3):11.) [7] 肖福仁. 针状铁素体管线钢的组织控制与细化工艺研究[D]. 秦皇岛:燕山大学,2003.(XIAO Fu-ren. Research on Microstructure Control and Refinement Technology for Acicular Ferrite Pipeline Steels[D]. Qinhuangdao:Yanshan University,2003.) [8] 赵明纯. 新一代针状铁素体管线钢的组织与性能研究[D]. 沈阳:中国科学院金属研究所,2003.(ZHAO Ming-chun. Microstructure and Property of New-Generation Acicular Ferrite Pipeline Steel[D]. Shenyang:Institute of Metal Research,Chinese Academy of Sciences,2003.) [9] XIAO F,LIAO B,REN D,et al. Acicular ferritic microstructure of a low-carbon Mn-Mo-Nb microalloyed pipeline steel[J]. Materials Characterization,2005,54(4/5):305. [10] 王伟,单以银,杨柯. 超低碳微合金管线钢中针状铁素体的组成对强度的影响[J]. 金属学报,2007,43(6):578.(WANG Wei,SHAN Yi-yin,YANG Ke. Effect of acicular ferrite constitution on strength of ultralow-carbon micro-alloyed pipeline steel[J]. Acta Metallurgica Sinica,2007,43(6):578.) [11] 由洋,王学敏,尚成嘉. 奥氏体化温度对HSLA100高强度低合金钢组织及冲击韧性的影响[J]. 金属学报,2012,48(11):1290.(YOU Yang,WANG Xue-min,SHANG Cheng-jia. Influence of austenitizing temperature on the microstructure and impact toughness of a high strength low alloy HSLA100 steel[J]. Acta Metallurgica Sinica,2012,48(11):1290.) [12] 王小勇,潘涛,王华,等. Ni-Cr-Mo-B超厚钢板表面低碳回火马氏体组织的韧性研究[J]. 金属学报,2012,48(4):401.(WANG Xiao-yong,PAN Tao,WANG Hua,et al. Investigation of the toughness of low carbon tempered martensite in the surface of Ni-Cr-Mo-B ultra-heavy plate steel[J]. Acta Metallurgica Sinica,2012,48(4):401.) [13] 刘东升,程丙贵,罗咪. F460高强韧厚船板焊接热影响区的组织和冲击断裂行为[J]. 金属学报,2011,47(10):1233.(LIU Dong-sheng,CHENG Bing-gui,LUO Mi. Microstructure and impact fracture behavior of HAZ of F460 heavy ship plate with high strength and toughness[J]. Acta Metallurgica Sinica,2011,47(10):1233.) [14] 狄国标,刘振宇,郝利强,等. 海洋平台用钢的生产现状及发展趋势[J]. 机械工程材料,2008,32(8):1.(DI Guo-biao,LIU Zhen-yu,HAO Li-qiang,et al. Present production state and development tendency of offshore platform steels[J]. Materials for Mechanical Engineering,2008,32(8):1.) [15] ZHOU T,YU H,HU J,et al. Study of microstructural evolution and strength-toughness mechanism of heavy-wall induction bend pipe[J]. Materials Science and Engineering A,2014,615(6):436. [16] XIE Z J,FANG Y P,HAN G,et al. Structure-property relationship in a 960 MPa grade ultrahigh strength low carbon niobium-vanadium microalloyed steel:The significance of high frequency induction tempering[J]. Materials Science and Engineering A,2014,618(8):112. [17] WANG C,WANG M,SHI J,et al. Effect of microstructural refinement on the toughness of low carbon martensitic steel[J]. Scripta Materialia,2008,58(6):492. [18] Schino A D,Guarnaschelli C. Effect of microstructure on cleavage resistance of high-strength quenched and tempered steels[J]. Materials Letters,2009,63(22):1968. [19] 王伟. 高性能管线钢的组织及强韧化机理研究[D]. 沈阳:中国科学院金属研究所,2009.(WANG Wei. Study on Microstructure and Strengthening and Toughening Mechanism of High Performance Pipeline Steels[D]. Shenyang:Institute of Metal Research,Chinese Academy of Sciences,2009.) [20] 高惠临. 管线钢与管线钢管[M]. 北京:中国石化出版社,2012.(GAO Hui-lin. Pipe Line Steel and Pipeline[M]. Beijing:China Petrochemical Press,2012.) [21] Davis C L,King J E. Cleavage initiation in the intercritically reheated coarse-grained heat-affected zone:Part I. Fractographic evidence[J]. Metallurgical and Materials Transactions A:Physical Metallurgy and,Materials Science,1994,25(3):563.
[22] 孙莹,于庆波. 多边形铁素体含量对X60、X70管线钢DWTT断口纤维率的影响[J]. 材料热处理学报,2014,35(3):105.(SUN Ying,YU Qing-bo. Effect of polygonal ferrite on shear-area percentage of DWTT fracture of pipeline steels X60 and X70[J]. Transactions of Materials and Heat Treatment,2014,35(3):105.) [23] 赵连玉. 高性能管线钢组织对力学性能及抗H2S腐蚀性能的影响[D]. 沈阳:中国科学院金属研究所,2013.(ZHAO Lian-yu. Influence of microstructure on the mechanical property and the anti-H2S property of high performance pipeline steel[D]. Shenyang:Institute of Metal Research,Chinese Academy of Sciences,2013.) [24] 牛延龙,刘清友,贾书君,等. X80级高强低合金管线钢组织与冲击韧性[J]. 钢铁,2019,54(2):67.(NIU Yan-long,LIU Qing-you,JIA Shu-jun,et al. Microstructure and impact toughness of X80 grade high strength low alloy pipeline steel[J]. Iron and Steel,2019,54(2):67.) [25] ZHONG Y,XIAO F,ZHANG J,et al. In situ TEM study of the effect of M/A films at grain boundaries on crack propagation in an ultra-fine acicular ferrite pipeline steel[J]. Acta Materialia,2006,54(2):435. [26] Dáz-Fuentes M,Iza-Mendia A,Gutiérrez I. Analysis of different acicular ferrite microstructures in low-carbon steels by electron backscattered diffraction. Study of their toughness behavior[J]. Metallurgical and Materials Transactions A,2003,34(11):2505. [27] Hwang B,Kim Y G,Lee S,et al. Effective grain size and charpy impact properties of high-toughness X70 pipeline steels[J]. Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,2005,36(8):2107.
2020, Vol. 55 
