Evaluation of cleanliness and distribution of inclusions in the thickness direction of interstitial free (IF) steel slabs

GAO Shuai; WANG Min; GUO Jian-long; WANG Hao; ZHI Jian-guo; BAO Yan-ping

doi:10.13374/j.issn2095-9389.2019.03.22.004

Volume 42 Issue 2

Feb. 2020

Turn off MathJax

Article Contents

Article Navigation > Chinese Journal of Engineering > 2020 > 42(2): 194-202

GAO Shuai, WANG Min, GUO Jian-long, WANG Hao, ZHI Jian-guo, BAO Yan-ping. Evaluation of cleanliness and distribution of inclusions in the thickness direction of interstitial free (IF) steel slabs[J]. Chinese Journal of Engineering, 2020, 42(2): 194-202. doi: 10.13374/j.issn2095-9389.2019.03.22.004

Citation:

GAO Shuai, WANG Min, GUO Jian-long, WANG Hao, ZHI Jian-guo, BAO Yan-ping. Evaluation of cleanliness and distribution of inclusions in the thickness direction of interstitial free (IF) steel slabs[J]. Chinese Journal of Engineering, 2020, 42(2): 194-202. doi: 10.13374/j.issn2095-9389.2019.03.22.004

Citation:

GAO Shuai, WANG Min, GUO Jian-long, WANG Hao, ZHI Jian-guo, BAO Yan-ping. Evaluation of cleanliness and distribution of inclusions in the thickness direction of interstitial free (IF) steel slabs[J]. Chinese Journal of Engineering, 2020, 42(2): 194-202. doi: 10.13374/j.issn2095-9389.2019.03.22.004

PDF( 1357 KB)

Evaluation of cleanliness and distribution of inclusions in the thickness direction of interstitial free (IF) steel slabs

doi: 10.13374/j.issn2095-9389.2019.03.22.004

1.
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
2.
Technical Center of Baotou Iron and Steel (Group) Co., Ltd., Baotou 014010, China

More Information

Corresponding author: E-mail: worldmind@163.com
Received Date: 2019-03-22
Publish Date: 2020-02-01

Abstract

Abstract

During the production of Al-killed titanium-alloyed interstitial free steel, to reduce defects in cold rolled sheets and decrease the influence of inclusions on the properties of the steel, it is important to clarify the distribution of inclusions in the thickness direction of IF (interstitial free) steel along the slab. In this study, standard metallographic techniques were employed to analyze the total oxygen and nitrogen by performing scanning electron microscopy, energy spectroscopy, automatic scanning electron microscopy, and original morphology analysis. The results show that the average mass fractions of T.O and N are 1.6 × 10^?5 and 1.7 × 10^?5, respectively, and the T.O for the 1/8 thickness from the inner arc is 2.0 × 10^?5, while the content of N for between the 1/4 and 3/8 thickness from the inner arc is 1.8 × 10^?5. A total of 1177 inclusions were counted. More than 70% of inclusions are within 5 μm in size, and the average size of inclusions in the thickness direction is 2.8 μm. The sizes of inclusions for the 3/8 thickness from both the inner and outer arcs are larger at 4.0 μm and 4.4 μm, respectively. The amount of precipitation of TiN is large in the slab center, and there are mainly Al₂O₃ and Al₂O₃–TiO_x near the inner and outer arc surfaces with sizes between 5 and 10 μm. Al₂O₃–TiN distributes irregularly in the 1/4 thickness from the inner and outer arcs, and the size fluctuates between 3 and 5 μm. The size of TiN during solidification fluctuates between 3 and 6 μm. TiN precipitates in the liquid and δ phase of the solidification front when the solidification rate is between 0.646 and 0.680, and the size fluctuates between 3 and 6 μm.
- slabs,
- thickness,
- inclusions,
- distribution,
- titanium nitride,
- precipitation

FullText(HTML)

References(28)

References

[1]	Wang R, Bao Y P, Yan Z J, et al. Comparison between the surface defects caused by Al₂O₃ and TiN inclusions in interstitial-free steel auto sheets. Int J Miner Metall Mater, 2019, 26(2): 178 doi: 10.1007/s12613-019-1722-z
[2]	Guo J L, Bao Y P, Wang M. Cleanliness of Ti-bearing Al-killed ultra-low-carbon steel during different heating processes. Int J Miner Metall Mater, 2017, 24(12): 1370 doi: 10.1007/s12613-017-1529-8
[3]	Xiao C, Cui H. Effect of Al content on inclusions in the automobile high strength steel. Chin J Eng, 2018, 40(增刊1): 29 肖超, 崔衡. Al含量對汽車用高強鋼中夾雜物的影響. 工程科學學報, 2018, 40(增刊1):29)
[4]	趙成林, 唐復平, 朱曉雷, 等. IF鋼連鑄坯表層夾雜分布特征的試驗. 鋼鐵, 2017, 52(12):42 Zhao C L, Tang F P, Zhu X L, et al. Experiment on distribution characteristics of surface inclusions in IF steel continuous casting billet steel making. Iron Steel, 2017, 52(12): 42
[5]	周萌, 姜敏, 苑鵬, 等. 超低碳鋼連鑄坯厚度方向大尺寸夾雜物分布特征. 煉鋼, 2016, 32(2):60 Zhou M, Jiang M, Yuan P, et al. Characterization of large inclusions along the thickness direction in the ultra-low carbon steel slab. Steelmaking, 2016, 32(2): 60
[6]	Wang M, Bao Y P, Cui H, et al. Surface cleanliness evaluation in Ti stabilised ultralow carbon (Ti-IF) steel. Ironmaking Steelmaking, 2011, 38(5): 386 doi: 10.1179/1743281211Y.0000000016
[7]	王敏, 包燕平, 楊荃, 等. IF鋼鑄坯厚度方向潔凈度演變. 工程科學學報, 2015, 37(3):307 Wang M, Bao Y P, Yang Q, et al. Cleanliness evolution of interstitial free (IF) steel slabs in the thickness direction. Chin J Eng, 2015, 37(3): 307
[8]	Peng Z G, Qi J H, Yang C W. Influence of slag denaturalization on inclusions in IF steel. Chin J Eng, 2018, 40(增刊1): 177 彭著剛, 齊江華, 楊成威. 頂渣改質工藝對IF鋼夾雜物的影響. 工程科學學報, 2018, 40(增刊1):177)
[9]	Guo J L, Bao Y P, Wang M. Steel slag in China: treatment, recycling, and management. Waste Manage, 2018, 78: 318 doi: 10.1016/j.wasman.2018.04.045
[10]	顧超, 趙立華, 甘鵬. 超低碳鋼精煉過程中Fe?Al?Ti?O類復合氧化物夾雜的演變與控制. 工程科學學報, 2019, 41(6):757 Gu C, Zhao L H, Gan P. Revolution and control of Fe?Al?Ti?O complex oxide inclusions in ultralow-carbon steel during refining process. Chin J Eng, 2019, 41(6): 757
[11]	Bao Y P, Wang M, Jiang W. A method for observing the three-dimensional morphologies of inclusions in steel. Int J Miner Metall Mater, 2012, 19(2): 111 doi: 10.1007/s12613-012-0524-3
[12]	Wang H, Li J, Shi C B, et al. Evolution of Al₂O₃ inclusions by magnesium treatment in H13 hot work die steel. Ironmaking Steelmaking, 2017, 44(2): 128 doi: 10.1080/03019233.2016.1165498
[13]	Bramfitt B L. The effect of carbide and nitride additions on the heterogeneous nucleation behavior of liquid iron. Metall Mater Trans B, 1970, 1(7): 1987 doi: 10.1007/BF02642799
[14]	楊亮. 電渣重熔GCr15SiMn軸承鋼TiN夾雜物形成機理及控制工藝[學位論文]. 北京: 北京科技大學, 2017 Yang L. Generation Mechanism and Control Technology of TiN Inclusion for GCr15SiMn in ESR Process[Dissertation]. Beijing: University of Science and Technology Beijing, 2017
[15]	Chase Jr M W, Curnutt J L, Downey Jr J R, et al. JANAF thermochemical tables, 1982 supplement. J Phys Chem Ref Data, 1982, 11(3): 695 doi: 10.1063/1.555666
[16]	Itoh H, Hino M, Ban-Ya S. Thermodynamics on the formation of spinel nonmetallic inclusion in liquid steel. Metall Mater Trans B, 1997, 28(5): 953 doi: 10.1007/s11663-997-0023-5
[17]	Choudhary S K, Ghosh A. Mathematical model for prediction of composition of inclusions formed during solidification of liquid steel. ISIJ Int, 2009, 49(12): 1819 doi: 10.2355/isijinternational.49.1819
[18]	陳家祥. 煉鋼常用圖表數據手冊. 2版. 北京: 冶金工業出版社, 2010 Chen J X. Steelmaking Common Chart Data Sheet. 2nd Ed. Beijing: Metallurgical Industry Press, 2010
[19]	Kraft T, Chang Y A. Predicting microstructure and microsegregation in multicomponent alloys. JOM, 1997, 49(12): 20 doi: 10.1007/s11837-997-0025-4
[20]	郭漢杰. 冶金物理化學教程. 2版. 北京: 冶金工業出版, 2006 Guo H J. Metallurgical Physical Chemistry Course. 2nd Ed. Beijing: Metallurgical Industry Press, 2006
[21]	Ueshima Y, Mizoguchi S, Matsumiya T, et al. Analysis of solute distribution in dendrites of carbon steel with δ/γ transformation during solidification. Metall Trans B, 1986, 17(4): 845 doi: 10.1007/BF02657148
[22]	Ganesan S, Poirier D R. Solute redistribution in dendritic solidification with diffusion in the solid. J Cryst Growth, 1989, 97(3-4): 851 doi: 10.1016/0022-0248(89)90587-3
[23]	Ohnaka I. Mathematical analysis of solute redistribution during solidification with diffusion in solid phase. Trans Iron Steel Inst Jpn, 1986, 26(12): 1045 doi: 10.2355/isijinternational1966.26.1045
[24]	Goto H, Miyazawa K, Yamada W, et al. Effect of cooling rate on composition of oxides precipitated during solidification of steels. ISIJ Int, 1995, 35(6): 708 doi: 10.2355/isijinternational.35.708
[25]	王金永, 劉建華, 劉建飛, 等. Ti-IF鋼凝固過程中TiN的析出機理和規律. 北京科技大學學報, 2014, 36(8):1025 Wang J Y, Liu J H, Liu J F, et al. Precipitation mechanism and behavior of TiN during Ti-IF steel solidification. J Univ Sci Technol Beijing, 2014, 36(8): 1025
[26]	胡漢起. 金屬凝固原理. 北京: 機械工業出版社, 1998 Hu H Q. Principle of Metal Solidification. Beijing: Mechanical Industry Press, 1998
[27]	Won Y M, Thomas B G. Simple model of microsegregation during solidification of steels. Metall Mater Trans A, 2001, 32(7): 1755 doi: 10.1007/s11661-001-0152-4
[28]	Ma Z T, Janke D. Characteristics of oxide precipitation and growth during solidification of deoxidized steel. ISIJ Int, 1998, 38(1): 46 doi: 10.2355/isijinternational.38.46