硼对无氟保护渣熔渣微观结构的影响

doi:10.13228/j.boyuan.issn0449-749x.20210608

Abstract
Figure/Table
References
Related Citation (15)

Download: PDF (2981 KB) HTML (1 KB)
Export: BibTeX | EndNote (RIS)

Abstract Nowdays, under the background of steel overcapacity and energy conservation in the steel industry, actively looking for substitutes to fluorine in mold fluxes and developing new fluorine-free mold fluxes have become an important way to achieve green and efficient continuous casting production. As an ideal substitute for fluorine, boron has become a new research focus of fluorine-free mold fluxes technology due to its economic cost and fluxing effect, and it is considered to have the broadest application prospects. In order to explore the melting and crystallization mechanism of boron-containing and fluorine-free mold fluxes, and to clarify the internal cause for the change of viscosity properties of boron-containing and fluorine-free mold fluxes from the perspective of the change of melt microstructure, blast furnace slag, limestone, quartz sand, soda ash and borax was used as the main raw material to prepare boron-containing and fluorine-free mold fluxes, in order to realize its industrial application. Combined with Raman spectroscopy and Scigress molecular dynamics simulation, the microstructure such as bond length, coordination number and structural unit of fluorine-free mold fluxes were analyze. The results show that as the borax content increases from 4% to 16%, the structure of boron-oxygen backbone in the slag has undergone major changes, the average coordination number of B—O increases from 3.028 to 3.096, and the average coordination number of Si—B increases from 0.229 to 0.898, moreover, the [BO₃] trihedron transforms into [BO₄] tetrahedron, and the average bond length of B—O remains unchanged at 1.375 nm. The number of bridging oxygen in the slag increases, and the structural unit changes from a simple island-like structure and a ring-like structure to a complex one. The layered structure and the framework structure are transformed, forming a complex borosilicate structure, which increases the DOP of slag, as a result, atomic groups and the migration resistance of ions is strengthened. This is not conducive to the nucleation and growth of crystals, and inhibits the crystallization of mold fluxes, thereby reducing the viscosity of mold fluxes further. On the whole, when the borax content in the boron-containing fluorine-free slag system is 7%-16%, the slag polymerization degree is higher, the network structure is more complex, and the viscosity stability is better.

Key words： borax fluorine-free mold fluxes slag structure molecular dynamics Raman spectroscopy

Received: 30 September 2021

	Service

	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	YAN Xiao-peng
	LIU Lei
	HAN Xiu-li
	WANG Yin-hui
	ZHANG Di

Cite this article:

YAN Xiao-peng,LIU Lei,HAN Xiu-li等. Effect of boron on microstructure of fluorine-free mold fluxes[J]. Iron and Steel, 2022, 57(5): 72-80.

URL:

http://www.chinamet.cn/Jweb_gt/EN/10.13228/j.boyuan.issn0449-749x.20210608 OR http://www.chinamet.cn/Jweb_gt/EN/Y2022/V57/I5/72

[1] 陈清泉. 连铸结晶器保护渣研究[D].武汉:武汉科技大学,2009.(CHEN Qing-quan. Study on Mold Flux for Casting[D]. Wuhan:Wuhan University of Science and Technology,2009.)
[2] 丁满堂.无氟保护渣的研制[J].炼钢,2013,29(6):57.(DING Man-tang. Development of fluoride-free mold flux[J]. Steelmaking,2013,29(6):57.)
[3] 赵俊学,赵忠宇,尚南,等.连铸保护渣中氟化物作用及影响分析[J].钢铁,2018,53(10):8.(ZHAO Jun-xue,ZHAO Zhong-yu,SHANG Nan, et al. Analysis on influence of fluoride in mold powder of continuous casting[J]. Iron and Steel, 2018,53(10):8.)
[4] 赵俊学,王泽,赵忠宇,等.氟化物挥发对连铸保护渣熔点的影响[J].钢铁,2019,54(8):181.(ZHAO Jun-xue,WANG Ze, ZHAO Zhong-yu, et al. Influence of fluoride evaporates on melting point of molding powder for continous casting[J].Iron and Steel, 2019,54(8):181.)
[5] 文光华,唐萍,李书成,等.无氟板坯连铸结晶器保护渣的研究[J].钢铁,2005,40(7):29.(WEN Guang-hua,TANG Ping,LI Shu-cheng, et al. Study of fluoride-free mold powder for slab continuous casting[J]. Iron and Steel, 2005,40(7):29.)
[6] 李桂荣,王宏明,李敬生,等.含B₂O₃无氟连铸保护渣物理性能的研究[J].特殊钢,2005,25(3):12.(LI Gui-rong,WANG Hong-ming,LI Jing-sheng, et al. A study on physical properties of free fluoride mould powder containing B₂O₃[J]. Special Steel, 2005,25(3):12.)
[7] ZHOU L, WANG W, LU B, et al. Effect of basicity and B₂O₃ on viscosity, melting and crystallization behaviors of low fluorine mold fluxes for casting medium carbon steels[J]. Metals and Materials International, 2015, 21(1):126.
[8] 王宏明,郭亚,李桂荣.CaO-SiO₂-B₂O₃-硼泥渣系的熔化性能及渣系结构分析[J].江苏大学学报(自然科学版),2016,37(6):675.(WANG Hong-ming,GUO Ya,LI Gui-rong. Analyses of melting properties and structure of CaO-SiO₂-B₂O₃-boron mudslag system[J]. Journal of Jiangsu University(Natural Science),2016,37(6):675.)
[9] Kharlashin P S. Investigation of viscosity and fusibility properties in order to optimize compositions of slag-forming mixtures used for continous steel casting at OAO MK Azovetal[J]. Steel in Translation,1999,115(4):34.
[10] 吴婷. 低反应性连铸保护渣熔体的微结构特征及宏观性能研究[D].重庆:重庆大学,2017.(WU Ting. Study on Microstructure and Macroproperty of Mould Fluxes with Low-reactivity[D]. Chongqing:Chongqing University,2017.)
[11] ZHANG L, WANG W, XIE S, et al. Effect of basicity and B₂O₃ on the viscosity and structure of fluorine-free mold flux[J]. Journal of Non-Crystalline Solids, 2017, 460(5):113.
[12] 束奇峰,王珍,Klug J,等. TiO₂和B₂O₃对Al₂O₃-CaO-MgO-Na₂O-SiO₂渣系结晶行为的作用[J]. 中国稀土学报,2012,30(专辑):144.(SHU Qi-feng,WANG Zhen,Klug J,et al. Effect of TiO₂ and B₂O₃ on the crystallization behavior of Al₂O₃-CaO-MgO-Na₂O-SiO₂ slag system[J]. Journal of the Chinese Society of Rare Earths, 2012,30(Album):144.)
[13] 王杏娟,田阔,樊亚鹏,等.TiO₂对连铸三元无氟CaO-SiO₂-TiO₂渣系特性的影响[J].材料导报,2018,32(12):2100.(WANG Xing-juan,TIAN Kuo, FAN Ya-peng, et al. Impact of TiO₂ on properties of three element fluorine free CaO-SiO₂-TiO₂ slag system for continuous casting[J]. Materials Reports, 2018,32(12):2100.)
[14] 王杏娟,靳贺斌,朱立光,等.B₂O₃对CaO-Al₂O₃-SiO₂基连铸保护渣性能及结构的影响[J].材料导报,2019,33(8):1395.(WANG Xing-juan,JI He-bin,ZHU Li-guang, et al. Effect of B₂O₃ on properties and structure of CaO-Al₂O₃-SiO₂ continuous casting mold flux[J]. Materials Reports, 2019,33(8):1395.)
[15] 韩文殿,仇圣桃,干勇,等.含TiO₂无氟保护渣的传热研究及生产实践[J].钢铁研究学报,2006,18(1):9.(HAN Wen-dian,QIU Sheng-tao,GAN Yong, et al. Heat transfer and practical application of fluoride-free flux containing TiO₂[J]. Journal of Iron and Steel Research,2006,18(1):9.)
[16] QI X, WEN G H, TANG P. Investigation on heat transfer performance of fluoride-free and titanium-bearing mold fluxes[J]. Journal of Non-Crystalline Solids, 2008, 354(52/54):5444.
[17] Nakada H,Nagata K. Crystallization of CaO-SiO₂-TiO₂ slag as a candidate for fluorine free mold flux[J]. Transactions of the Iron and Steel Institute of Japan, 2006, 46(3):441.
[18] 潘伟杰,李民,何生平,等.Na₂O对超高碱度连铸保护渣性能的影响[J].钢铁,2022,57(1):93.(PAN Wei-jie,LI Min,HE Sheng-ping,et al.Effect of Na₂O on properties of ultra-high basicity continuous casting mold fluxes[J]. Iron and Steel,2022,57(1):93.)
[19] 靳贺斌,吉俊德,何生平,等.钢渣反应对高钛钢保护渣物化特性的影响[J].连铸,2021(6):59.(JIN He-bin,JI Jun-de,HE Sheng-ping,et al.Effect of steel slag reaction on physicochemical properties of mold fluxes of high-titanium steel[J] Continuous Casting,2021(6):59.)
[20] 董晓旭,张淑会,吕庆.低钛高炉渣脱硫能力研究[J].矿冶工程,2017,37(2):88.(DONG Xiao-xu,ZHAO Shu-hui,LÜ Qing.Desulphurization effect of BF slag with low titanium content[J].Mining and Metallurgical Engineering,2017,37(2):88.)
[21] 王新月,金山同,张铁军.低硫钢连铸过程结晶器内渣-钢间硫的迁移[J].特殊钢,2006, 22(5):18.(WANG Xin-yue,JIN Shan-tong,ZHANG Tie-jun.Transfer of sulphur between flux and liquid steel in mold during low sulphur steel concasting[J]. Special Steel,2006,22(5):18.)
[22] 李殿明, 邵明天, 杨宪礼, 等. 连铸结晶器保护渣应用技术[M]. 北京:冶金工业出版社, 2008.(LI Dian-ming,SHAO Ming-tian,YANG Xian-li, et al. Application Technology of Mold Powder for Continuous Casting[M]. Beijing: Metallurgical Industry Press,2008.)
[23] 张燮. FeO-SiO₂-V₂O₃渣系熔融结构和性质的多尺度分析[D].重庆:重庆大学,2012.(ZHANG Xie. Multi-scale Analyses of Molten Structure and Properties of FeO-SiO₂-V₂O₃ System[D].Chongqing: Chongqing University, 2012.)
[24] Mills K C,Keene B J.Physical properties of BOS slags[J].International Materials Reviews, 2013, 32(1):1.
[25] 赵谦,祖群,齐亮, 等. 分子动力学模拟预测氧化钠含量对二元钠硅酸盐玻璃弹性模量的影响[J]. 硅酸盐学报,2018,46(11):1558.(ZHAO Qian,ZU Qun,QI Liang, et al. Molecular dynamics simulation predicts the effect of sodium oxide content on elastic modulus of binary sodium silicate glass[J]. Acta Silicata Sinica,2018,46(11):1558.)
[26] Swenson Jan, Börjesson Lars. Intermediate-range structure and conductivity of fast ion-conducting borate glasses[J]. Journal of Non-Crystalline Solids, 1998, 232/233/234(1):658.
[27] GAO Jin-xing, WEN Guang-hua, HUANG Ting, et al. Effects of the composition on the structure and viscosity of the CaO-SiO₂-based mold flux[J]. Journal of Non-Crystalline Solids, 2016, 435(23):33.
[28] LI Jiang-ling, SHU Qi-feng. Structural study of glassy CaO-SiO₂-CaF₂-TiO₂ slags by raman spectroscopy and MAS-NMR[J]. ISIJ International, 2014, 54(4):721.
[29] Kamitsos E I, Chryssikos G D, Karakassides M A. Vibrational spectra of magnesium-sodium-borate glasses. 1. Far-infrared investigation of the cation-site interactions[J]. Cheminform, 1987, 18(20):275.
[30] Hidi IJ, Melinte G, Stefan R, et al. The study of the structure and bioactivity of the B₂O₃·Na₂O·P₂O₅ system[J]. Journal of Raman Spectroscopy, 2013, 44(27):1187.
[31] Youngman R E, Zwanziger J W. Network modification in potassium borate glasses: Structural studies with NMR and Raman spectroscopies[J]. Journal of Physical Chemistry, 1996, 100(41):16720.
[32] 王杏娟,武宾宾,朱立光, 等. 无氟连铸保护渣流变特性的研究[J].钢铁钒钛,2017,38(4):135.(WANG Xing-juan,WU Bin-bin,ZHU Li-guang, et al. Study on rheological properties of fluorine-free continuous casting mould powder[J]. Iron Steel Vanadium Titanium,2017,38(4):135.)