Viscosity detection and the estimation model of fluorine-containing mold flux for continuous casting

ZHAO Zhong-yu; ZHAO Jun-xue; TAN Ze-xin; QU Bo-qiao; CUI Ya-ru

doi:10.13374/j.issn2095-9389.2020.05.03.002

Volume 43 Issue 4

Mar. 2021

Turn off MathJax

Article Contents

Article Navigation > Chinese Journal of Engineering > 2021 > 43(4): 529-536

ZHAO Zhong-yu, ZHAO Jun-xue, TAN Ze-xin, QU Bo-qiao, CUI Ya-ru. Viscosity detection and the estimation model of fluorine-containing mold flux for continuous casting[J]. Chinese Journal of Engineering, 2021, 43(4): 529-536. doi: 10.13374/j.issn2095-9389.2020.05.03.002

Citation:

ZHAO Zhong-yu, ZHAO Jun-xue, TAN Ze-xin, QU Bo-qiao, CUI Ya-ru. Viscosity detection and the estimation model of fluorine-containing mold flux for continuous casting[J]. Chinese Journal of Engineering, 2021, 43(4): 529-536. doi: 10.13374/j.issn2095-9389.2020.05.03.002

Citation:

PDF( 1001 KB)

Viscosity detection and the estimation model of fluorine-containing mold flux for continuous casting

doi: 10.13374/j.issn2095-9389.2020.05.03.002

1.
School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
2.
CISDI R&D Co. Ltd, Chongqing 401120, China

More Information

Corresponding author: E-mail: zhaojunxue1962@126.com
Received Date: 2020-05-03
Publish Date: 2021-04-26

Abstract

Abstract

Mold flux plays a significant role in the continuous casting of steel. Especially, the viscosity (or its inverse, fluidity) of mold flux is a key parameter for industrial applications to aid in product quality. In this paper, viscosities of different types of fluorine-containing continuous casting mold fluxes were first measured by the rotating cylinder method, and then a new viscosity estimation model was established based on the Arrhenius equation combined with nonlinear regression analysis to analyze the influence of component changes on the viscosity. Combining model calculation and experimental measurement, an iso-viscosity diagram of the CaF₂–Na₂O–Al₂O₃–CaO–SiO₂–MgO slag system was also created. It is found that deviation within 10% is calculated using the model in this study compared with the traditional viscosity estimation models of different types of fluorine-containing continuous casting mold fluxes but gradually increases when the w(CaF₂) of slag exceeds 20%, mainly due to the change of slag composition caused by fluoride volatilization. Finally, the measured value cannot correspond to the composition of the initial slag, and the model cannot give an accurate estimated value. It is also found that an increase of CaF₂ can significantly reduce viscosity, whereas, the effect of Al₂O₃ and Na₂O on viscosity is restricted by CaF₂ content. When w(CaF₂) > 17%, the viscosity of slag decreases with increasing w(Al₂O₃), and when w(CaF₂) < 17%, the viscosity of slag increases significantly with increasing w(Al₂O₃). When w(CaF₂) > 11.5%, the viscosity of the slag system decreases significantly with increasing w(Na₂O) mass. When w(CaF₂) < 11.5%, the effect of Na₂O on viscosity is not obvious. In addition, the diagram shows that the mass fraction of CaF₂ in the low viscosity area is nearly 14%. This shows that the viscosity and fluidity of mold flux can be improved by adjusting the component ratio in this iso-viscosity diagram for applications in the steel industry.
- continuous casting mold flux,
- CaF₂,
- viscosity estimation model,
- nonlinear regression analysis,
- iso-viscosity diagram

FullText(HTML)

References(27)

References

[1]	王新華. 鋼鐵冶金: 煉鋼學. 北京: 高等教育出版社, 2007 Wang X H. Metallurgy of Iron and Steel: Steelmaking. Beijing: Higher Education Press, 2007
[2]	Anisimov K N, Longinov A M, Toptygin A M, et al. Investigation of the mold powder film structure and its influence on the developed surface in continuous casting. Steel Transl, 2016, 46(7): 489 doi: 10.3103/S0967091216070032
[3]	Viswanathan N N, Fatemeh S, Du S C, et al. Estimation of escape rate of volatile components SiF₄ and HF from slags containing CaF₂ during viscosity measurement. Steel Res, 1999, 70(2): 53 doi: 10.1002/srin.199905600
[4]	Cho J W, Yoo S, Park M S, et al. Improvement of castability and surface quality of continuously cast TWIP slabs by molten mold flux feeding technology. Metall Mater Trans B, 2017, 48(1): 187 doi: 10.1007/s11663-016-0818-3
[5]	Susa M, Sakamaki T, Kojima R. Chemical states of fluorine in CaF₂?CaO?SiO₂ and NaF?Na₂O?SiO₂ glassy slags from the perspective of electronic polarisability. Ironmaking Steelmaking, 2005, 32(1): 13 doi: 10.1179/174328105X15841
[6]	趙俊學, 趙忠宇, 尚南, 等. 連鑄保護渣中氟化物作用及影響分析. 鋼鐵, 2018, 53(10):8 Zhao J X, Zhao Z Y, Shang N, et al. Analysis on influence of fluoride in mold powder of continuous casting. Iron Steel, 2018, 53(10): 8
[7]	Li J Y, Zhang L, Tan Y, et al. Research of boron removal from polysilicon using CaO–Al₂O₃–SiO₂–CaF₂ slags. Vacuum, 2014, 103: 33 doi: 10.1016/j.vacuum.2013.12.002
[8]	王謙, 何生平, 李玉剛, 等. 中國連鑄保護渣技術現狀及發展需求. 連鑄, 2014(5):1 Wang Q, He S P, Li Y G, et al. Status and developing needs of mould fluxes for continuous casting in China. Continuous Cast, 2014(5): 1
[9]	Arefpour A R, Monshi A, Saidi A, et al. Effect of CaF₂ and MnO on mold powder viscosity and solidification during high-speed continuous casting. Refract Ind Ceram, 2013, 54(3): 203 doi: 10.1007/s11148-013-9575-x
[10]	Persson M, Seetharaman S, Seetharaman S. Kinetic studies of fluoride evaporation from slags. ISIJ Int, 2007, 47(12): 1711 doi: 10.2355/isijinternational.47.1711
[11]	Haverkamp R G. An XPS study of the fluorination of carbon anodes in molten NaF–AlF₃–CaF₂. J Mater Sci, 2012, 47(3): 1262 doi: 10.1007/s10853-011-5772-5
[12]	Shi C B, Cho J W, Zheng D L, et al. Fluoride evaporation and crystallization behavior of CaF₂–CaO–Al₂O₃–(TiO₂) slag for electroslag remelting of Ti-containing steels. Int J Miner Metall Mater, 2016, 23(6): 627 doi: 10.1007/s12613-016-1275-3
[13]	Park H S, Kim H, Sohn I. Influence of CaF₂ and Li₂O on the viscous behavior of calcium silicate melts containing 12 wt pct Na₂O. Metall Mater Trans B, 2011, 42(2): 324 doi: 10.1007/s11663-011-9474-9
[14]	Tong Z F, Qiao J L, Jiang X Y. Kinetics of Na₂O evaporation from CaO?Al₂O₃?SiO₂?MgO?TiO₂?Na₂O slags. Ironmaking Steelmaking, 2017, 44(4): 237 doi: 10.1080/03019233.2016.1210354
[15]	Park J Y, Ryu J W, Sohn I. In-situ crystallization of highly volatile commercial mold flux using an isolated observation system in the confocal laser scanning microscope. Metall Mater Trans B, 2014, 45(4): 1186 doi: 10.1007/s11663-014-0087-y
[16]	Shin S H, Cho J W, Kim S H. Structural investigations of CaO–CaF₂–SiO₂–Si₃N₄ based glasses by Raman spectroscopy and XPS considering its application to continuous casting of steels. Mater Des, 2015, 76: 1 doi: 10.1016/j.matdes.2015.03.035
[17]	Guo J M, Peng K W, Yi L, et al. Study on properties of Al₂O₃?CaO?SiO₂?CaF₂?MgO slag system. Appl Mech Mater, 2014, 513-517: 24 doi: 10.4028/www.scientific.net/AMM.513-517.24
[18]	趙俊學, 葛蓓蕾, 崔雅茹, 等. 含易揮發組元爐渣的高溫性能檢測. 工業加熱, 2016, 45(2):12 Zhao J X, Ge B L, Cui Y R, et al. High temperature properties measurement of slag with higher volatile content. Ind Heat, 2016, 45(2): 12
[19]	韓秀麗, 李沛. 堿度值R、F-含量和Na₂O含量對中碳鋼保護渣渣膜結晶體的影響規律. 河北聯合大學學報(自然科學版), 2014, 36(1):18 Han X L, Li P. Effect of alkalinity, F’s content and Na₂O content in steel slag film crystals. J Hebei United Univ Nat Sci Ed, 2014, 36(1): 18
[20]	趙顯久, 溫宏權, 張捷宇. 連鑄結晶器保護渣物相性能研究. 現代冶金, 2019, 47(3):46 Zhao X J, Wen H Q, Zhang J Y. The phase properties of mold flux in continuous casting mold flux. Mod Metall, 2019, 47(3): 46
[21]	Riboud P V, Roux Y, Lucas L D, et al. Improvement of continuous casting powders. Fachber Hiittenprax Metallweiterverarb, 1981(19): 859
[22]	Iida T, Sakai H, Kita Y, et al. An equation for accurate prediction of the viscosities of blast furnace type slags from chemical composition. ISIJ Int, 2000, 40(Suppl): S110 doi: 10.2355/isijinternational.40.Suppl_S110
[23]	Mills K C, Fox A B, Li Z, et al. Performance and properties of mould fluxes. Ironmaking Steelmaking, 2005, 32(1): 26 doi: 10.1179/174328105X15788
[24]	劉振學, 王力. 實驗設計與數據處理. 2版. 北京: 化學工業出版社, 2015 Liu Z X, Wang L. Experimental Design and Data Processing. 2nd Ed. Beijing: Chemical Industry Press, 2015
[25]	Mills K C, Sridhar S. Viscosities of ironmaking and steelmaking slags. Ironmaking Steelmaking, 1999, 26(4): 262 doi: 10.1179/030192399677121
[26]	潘志勝, 王謙, 何生平, 等. 連鑄保護渣組分對黏度的影響. 特鋼技術, 2010, 16(2):18 Pan Z S, Wang Q, He S P, et al. Effect of viscosity components on mould fluxes. Spec Steel Technol, 2010, 16(2): 18
[27]	Mills K C, Fox A B. The role of mould fluxes in continuous casting-so simple yet so complex. ISIJ Int, 2003, 43(10): 1479 doi: 10.2355/isijinternational.43.1479