1. Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 2. Hubei Province Key Laboratory of Systems Science on Metallurgical Processing, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 3. Metals Valley and Band Metallic(Foshan) Composite Materials Co., Ltd., Foshan 528000, Guangdong, China
Abstract：Due to the different cooling rates along the thickness direction,the surface and 1/4H(H represents thickness) of the ultra thick plate have different microstructures. In order to study the influence of microstructures on the strength and toughness of different parts of ultra thick plate,the tensile test at room temperature and impact test at low temperature were carried out. The microstructure and mechanical properties of the surface and 1/4H were characterized by SEM、TEM、EBSD analysis as well as other technical means. The results show that yield strength at the surface is slightly higher than that at 1/4H due to the small martensite block size and the higher dislocation density. The impact properties at low temperature of the surface and 1/4H are obviously different. Compared with 1/4H,-60 ℃ and -80 ℃ low temperature impact energy at the surface is reduced by 12.6% and 24.7%,respectively,which is attributed to the lower number density of large angle grain boundary (HAGB) and the higher internal stress concentration induced by the larger cooling rate at the surface.
[1] 杨才福,苏航. 高性能船舶及海洋工程用钢的开发[J]. 钢铁,2012,47(12):1.(YANG Cai-fu,SU Hang. Research and development of high-performance shipbuilding and marine engineering steel[J]. Iron and Steel,2012,47(12):1.) [2] 赵捷. 我国高品质船舶、海洋工程用钢研究进展[J]. 材料导报,2018,32(s1):428.(ZHAO Jie. Progress on high quality ship steel for ships and marine engineering steel in China[J]. Materials Reports,2018,32(s1):428.) [3] 刘艳,曹建宁,耿明山. 海洋平台用齿条钢特厚板坯料水冷模铸技术研发[J]. 钢铁,2018,53(2):91.(LIU Yan,CAO Jian-ning,GENG Ming-shan. Research and development of water-cooled casting technology for over-thick ingot blanks of offshore platform rack plate[J]. Iron and Steel,2018,53(2):91.) [4] 胡锋,王同良,车马俊,等. 特厚超高强海工钢表面回火马氏体组织对冲击韧性的影响[J]. 材料热处理学报,2017(10):80.(HU Feng,WANG Tong-liang,CHE Ma-jun,et al. Effect of tempered martensite at surface on impact toughness of extra-thick ultra-high strength marine steel[J]. Transactions of Materials and Heat Treatment,2017(10):80.) [5] LIU H,ZHANG H,LI J. Thickness dependence of toughness in ultra-heavy low-alloyed steel plate after quenching and tempering[J]. Metals-Open Access Metallurgy Journal,2018,8(8):628. [6] 李样兵,柳付芳,李杰,等. 大厚度严要求14Cr1MoR钢最佳热处理制度探究[J]. 中国冶金,2021,31(2):76. (LI Yang-bing,LIU Fu-fang,LI Jie,et al. Study on best heat treatment system of 14Cr1MoR steel with heavy thickness and strict requirements[J]. China Metallurgy,2021,31(2):76.) [7] 李样兵,赵国昌,龙杰,等. 轧后ACC提高超厚14Cr1MoR钢低温冲击韧性的生产实践[J]. 中国冶金,2020,30(2):84. (LI Yang-bing,ZHAO Guo-chang,LONG Jie,et al. Production practice of improving impact toughness of 14Cr1MoR steel plate by ACC after rolling[J]. China Metallurgy,2020,30(2):84.) [8] 张守清,胡小锋,杜瑜宾,等. 海洋平台用Ni-Cr-Mo-B超厚板的截面效应[J]. 金属学报,2020(9):1227.(ZHANG Shou-qing,HU Xiao-feng,DU Yu-bin,et al. Cross-section effect of Ni-Cr-Mo-B ultra-heavy steel plate for offshore platform[J]. Acta Metallurgica Sinica,2020(9):1227.) [9] 王小勇,潘涛,王华,等. Ni-Cr-Mo-B超厚板表面低碳回火马氏体组织的韧性研究[J]. 金属学报,2012(5):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(5):401.) [10] LUO Z J,SHEN J C,HANG S U,et al. Effect of substructure on toughness of lath martensite/bainite mixed structure in low-carbon steels[J]. Journal of Iron and Steel Research,International,2010,17(11):40. [11] Naylor J P. The influence of the lath morphology on the yield stress and transition temperature of martensitic-bainitic steels[J]. Metallurgical Transactions A,1979(7):861. [12] 董瀚,李桂芬,陈南平. 高强度30CrNiMnMoB钢的脆性断裂机理[J]. 钢铁,1997,32(7):49.(DONG Han,LI Gui-fen,CHEN Nan-ping,et al. On mechanism of brittle fracture of high strength 30GrNiMnMoB steel[J]. Iron and Steel,1997,32(7):49.) [13] 胡赓祥,蔡珣,戎咏华. 材料科学基础 [M]. 3版. 上海:上海交通大学出版社,2010.(HU Geng-xiang,CAI Xun,RONG Yong-hua. Fundamentals of Materials Science[M]. 3rd ed. Shanghai:Shanghai Jiaotong University Press,2010.) [14] 罗志俊. 10CrNi5Mo钢特厚板组织与性能关系研究[D]. 昆明:昆明理工大学,2010.(LUO Zhi-jun. Research on the Relationship Between Microstructure and Properties of 10CrNi5Mo Steel Extra-Thick Plate[D]. Kunming:Kunming University of Science and Technology,2010.) [15] LONG S L,LIANG Y L,JIANG Y,et al. Effect of quenching temperature on martensite multi-level microstructures and properties of strength and toughness in 20CrNi2Mo steel[J]. Materials Science and Engineering A,2016,676(31):38. [16] 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. [17] 刘宗昌,任慧平,安胜利. 马氏体相变[M]. 北京:科学出版社,2012.(LIU Zong-chang,REN Hui-ping,AN Sheng-li. Martensitic Transformation[M]. Beijing:Science Press,2012.) [18] 朱景川. 固态相变原理[M]. 北京:科学出版社,2010.(ZHU Jing-chuan. Solid State Phase Transition Principle[M]. Beijing:Science Press,2010.) [19] Somekawa H,Mukai T. Effect of grain refinement on fracture toughness in extruded pure magnesium[J]. Scripta Materialia,2005,53(9):1059. [20] 王春芳,王毛球,时捷,等. 低碳马氏体钢的微观组织及其对强度的影响[J]. 钢铁,2007,42(11):57.(WANG Chun-fang,WANG Mao-qiu,SHI Jie,et al. Microstructural characterization and its effect on strength of low carbon martensitic steel[J]. Iron and Steel,2007,42(11):57.) [21] Furuhara T,Kikumoto K,Saito H,et al. Phase transformation from fine-grained austenite[J]. ISIJ International,2008,48(8):1038. [22] 王小勇. 海洋工程用低合金高强度超厚板的淬透性与强韧性研究[D]. 北京:钢铁研究总院,2013.(WANG Xiao-yong. Research on Hardenability and Toughness of Low-Alloy High-Strength Ultra-Thick Plates for Offshore Engineering[D]. Beijing:Central Iron and Steel Research Institute,2013.) [23] 李振团,柴锋,杨才福,等. 淬火工艺对铜沉淀强化UHS钢组织性能的影响[J]. 钢铁,2019,54(6):79.(LI Zhen-tuan,CHAI Feng,YANG Cai-fu,et al. Effect of quenching process on microstructure and mechanical properties of Cu precipitated hardened ultra-high strength steel[J]. Iron and Steel,2019,54(6):79.) [24] 田景云,罗志俊,沈俊昶,等. 冷却速度对10Ni5CrMo钢组织和性能的影响[J]. 钢铁,2012,47(12):71.(TIAN Jing-yun,LUO Zhi-jun,SHEN Jun-chang,et al. Effect of cooling rate on microstructure and properties of 10Ni5CrMo steel[J]. Iron and Steel,2012,47(12):71.) [25] Tomita Y,Okabayashi K.Effect of microstructure on strength and toughness of heat-treated low alloy structural steels[J]. Metallurgical Transactions A,1986,17(7):1203. [26] 卢叶茂,梁益龙,龙绍檑,等. 淬火20CrNi2Mo低碳钢中大角度晶界对强度的影响[J]. 材料导报,2018,32(24):4339.(LU Ye-mao,LIANG Yi-long,LONG Shao-lei,et al. Effect of high angle boundaries on strength for 20CrNi2Mo steel[J]. Materials Reports,2018,32(24):4339.) [27] 牛延龙,刘清友,贾书君,等. 控冷工艺下组织及M/A岛对管线钢韧性的影响[J]. 钢铁,2020,55(6):91.(NIU Yan-long,LIU Qing-you,JIA Shu-jun,et al. Influence of microstructure and M/A island evolution on toughness of pipeline steel under controlled cooling process[J]. Iron and Steel,2020,55(6):91.) [28] 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.)
2021, Vol. 56 
