Cause analysis of low temperature toughness fluctuation of 550 MPa steel plate for offshore engineering
ZHU Kang-feng1,2, MA Heng3, SONG Xin-li1, JIA Juan1, LIANG Xiao-kai2, SUN Xin-jun2
1. The State Key Laboratory of Refractory Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 2. Engineering Steel Research Institute, Central Iron and Steel Research Institute Co., Ltd., Beijing 100081, China; 3. Yinshan Section Steel Co., Ltd., Laiwu Steel Group, Jinan 271105, Shandong, China
Abstract：The impact energy of 550 MPa Marine engineering steel fluctuates greatly at low temperature. In order to further explore the cause of low temperature toughness fluctuation,impact tests were carried out on the test steel at different temperatures (-100 ℃-room temperature). The impact fracture,microstructure,second phase and inclusions were analyzed with optical microscope,scanning electron microscope and transmission electron microscope. The reason of low temperature toughness fluctuation was analyzed and discussed by thermodynamics calculation. The results show that the strength of the tested steel meets the requirements of grade,the impact absorption energy decreases with decreasing temperature,and the toughness and brittleness transition temperature is about -50 ℃. At -60 ℃,the impact energy fluctuates greatly,and an extremely low value of 18 J appears. The fracture is quasi-cleavage fracture,the shear section rate is 8%,and there are compound inclusions of Ti,Nb(C,N) and MnS at the crack source. At the same temperature,the shear section of the test steel with impact energy of 122 J is 34%,and there are obvious dimples in the fracture. The microstructure of the test steel is mainly tempered bainite and very little ferrite. There are high density dislocations in bainite slat. There are (Fe,Cr)3C alloy cementite and a small amount of NbC and Cu-rich precipitates on grain boundary. The test steel mainly has small Angle grain boundary,and large Angle grain boundary is relatively low. There are a small amount of (Ca,Al,Mg,Mn,S) inclusions in the matrix,which are nearly round and polygonal in size between 1-3 μm,accounting for 85.87% of the total amount detected. The highest proportion of cas-oxide-MNS inclusions was 31.2%. Thermodynamic calculation results show that TiN precipitates earlier than MnS during solidification. Many factors,such as coarse precipitated phase of grain boundary and ingrain,inclusions,high proportion of small Angle grain boundary and immobile dislocation of plugging,have adverse effects on the impact toughness at low temperature. The existence of large titanium-containing precipitated phase is the key reason for the large fluctuation of impact toughness.
朱康峰, 麻衡, 宋新莉, 贾涓, 梁小凯, 孙新军. 550 MPa级海洋工程用钢板低温韧性波动原因分析[J]. 钢铁, 2022, 57(10): 178-187.
ZHU Kang-feng, MA Heng, SONG Xin-li, JIA Juan, LIANG Xiao-kai, SUN Xin-jun. Cause analysis of low temperature toughness fluctuation of 550 MPa steel plate for offshore engineering[J]. Iron and Steel, 2022, 57(10): 178-187.
[1] 张翔云. 700 MPa级海工钢组织调控及低温韧性研究[D]. 鞍山:辽宁科技大学,2020.(ZHANG Xiang-yun. Study on Microstructure Control and Low Temperature Toughness of 700 MPa Grade Offshore Steel[D]. Anshan:University of Science and Technology Liaoning,2020.) [2] 孙明煜. 低温用海洋工程用钢多相组织调控及力学行为研究[D]. 北京:北京科技大学,2020.(SUN Ming-yu. Study on Multi-Phase Regulation and Mechanical Behavior of Offshore Structural Steel for Low Temperature Service[D]. Beijing:University of Science and Technology Beijing,2020.) [3] YAN J B,LIEW J Y R,ZHANG M H,et al. Mechanical properties of normal strength mild steel and high strength steel S690 in low temperature relevant to Arctic environment[J]. Material and Design,2014(61):150. [4] 关建辉,张继明,孙林,等. 含Ti低碳微合金钢的力学行为和强化机理[J]. 钢铁钒钛,2020,41(6):107.(GUAN Jian-hui,ZHANG Jia-ming,SUN Lin,et al. Strengthening mechanism and mechanical behavior of low carbon microalloyed steel containing Ti[J]. Iron Steel Vanadium Titanium,2020,41(6):107.) [5] 赵培林,宗云. 显微组织对海洋工程用热轧H型钢低温断裂韧性的影响[J]. 金属热处理,2017,42(8):68.(ZHAO Pei-lin,ZONG Yun. Influence of microstructure on low temperature impact toughness of hot rolled H-shape steel for marine engineering[J]. Heat Treatment of Metals,2017,42(8):68.) [6] 潘晓丽,朱健,王秉新. 390 MPa级低合金高强钢的低温韧性[J]. 理化检验-物理分册,2012,48(4):221.(PAN Xiao-li,ZHU Jian,WANG Bing-xin. Low temperature toughness of 390 MPa grade high strength low alloy steel[J]. Physical Testing and Chemical Analysis(Part A:Physical Testing),2012,48(4):221.) [7] 温永红,唐获,武会宾,等. F40级船板低温韧性机理[J]. 北京科技大学学报,2008,30(7):724.(WEN Yong-hong,TANG Di,WU Hui-bin,et al. Low-temperature toughness characteristics of F40 hull structure steel[J]. Journal of University of Science and Technology Beijing,2008,30(7):724.) [8] 甘贵平,叶姜,樊雷. 回火处理对一种低碳贝氏体钢组织及低温韧性的影响[J]. 钢铁研究学报,2020,32(3):258.(GAN Gui-ping,YE Jiang,FAN Lei. Effect of tempering treatment on microstructure and low temperature toughness of a low carbon bainite steel[J]. Journal of Iron and Steel Research,2020,32(3):258.) [9] 陈赛克,李静媛. MnS+TiN夹杂物对超高强度钢韧性的影响[J]. 成都科技大学学报,1988(5):129.(CHEN Sai-ke,LI Jing-yuan. Effect of MnS+TiN inclusions on the toughness ultrahigh strength steels[J]. Journal of Chengdu University of Science and Technology,1988(5):129.) [10] 田钱仁,马骞,尚德礼,等. GCr15轴承钢中TiN复合夹杂物形成机理[J]. 辽宁科技大学学报,2018,41(3):173.(TIAN Qian-ren,MA Qian,SHANG De-li,et al. Formation mechanism of complex TiN inclusions in GCr15 bearing steel[J]. Journal of University of Science and Technology Liaoning,2018,41(3):173.) [11] 吴俊平,靳星,龙木军,等. 含钛微合金钢低温冲击韧性波动的原因与改进[J]. 中国冶金,2017,27(12):59.(WU Jun-ping,JIN Xing,LONG Mu-jun,et al. Cause analysis and improvement of undulation of low temperature impact property for Ti microalloyed steel[J]. China Metallurgy,2017,27(12):59.) [12] WANG B X,LIAN J B. Effect of microstructure on low-temperature toughness of a low carbon Nb-V-Ti microalloyed pipeline steel[J]. Materials Science and Engineering A,2014,592:50. [13] 李样兵,柳付芳,赵国昌,等. 14CrlMoR钢136 mm特厚板极限低温冲击韧性[J]. 特殊钢,2020,41(4):59.(LI Yang-bing,LIU Fu-fang,ZHAO Guo-chang,et al. Ultimate negative temperature impact toughness of 14CrlMoR steel 136 mm extra thick plate[J]. Special Steel,2020,41(4):59.) [14] 史智越,徐海峰,许达,等. 采用ASPEX和旋弯疲劳法表征GCr15轴承钢夹杂物[J]. 钢铁,2019,54(4):56.(SHI Zhi-yue,XU Hai-feng,XU Da,et al. Characterization of inclusions in GCr15 bearing steel by ASPEX and rotary bending fatigue methods[J]. Iron and Steel,2019,54(4):56.) [15] FU R,FENG D,CHEN X C. Effects of undersized inclusions on ductile fracture behavior of FeNi42 alloy in sheet tension[J]. Journal of Iron and Steel Research,International,2007,14(5):53. [16] 吕刚,何建丽,赵卫东. 夹杂物对金属材料成形及断裂影响的研究进展[J]. 塑性工程学报,2021,28(12):1.(LÜ Gang,HE Jian-li,ZHAO Wei-dong. Research progress on influence of inclusions on forming and fracture of metal materials[J]. Journal of Plasticity Engineering,2021,28(12):1.) [17] YAN W,SHAN Y Y,YANG K. Influence of TiN inclusions on the cleavage fracture behavior of low-carbon microalloyed steels[J]. Metallurgical and Materials Transactions A,2006,38A:1212. [18] 王帅,胡锋,李德发,等. TiN对高强度耐磨钢韧性的影响及其机制分析[J]. 中国冶金,2021,31(7):38.(WANG Shuai,HU Feng,LI De-fa,et al. Effect of TiN on toughness of high-strength wear-resistant steel and its mechanism analysis[J]. China Metallurgy,2021,31(7):38.) [19] YAN W,SHAN Y Y,YANG K. Effect of TiN inclusions on the impact toughness of low-carbon microalloyed steels[J]. Metallurgical and Materials Transactions A,2006,37:2147. [20] 雍岐龙. 钢铁材料中的第二相[M]. 北京:冶金工业出版社,2006.(YONG Qi-long. Secondary Phases in Steels[M]. Beijing:Metallurgical Industry Press,2006.) [21] 杨跃标,李宗强,邓深,等. 热轧钛微合金化高强钢低温冲击韧性的控制[J]. 钢铁,2021,56(3):42.(YANG Yue-biao,LI Zong-qiang,DENG Shen,et al. Low temperature impact toughness controlling for Ti-microalloyed high strength steel[J]. Iron and Steel,2021,56(3):42.)
2022, Vol. 57 
