Abstract：The submerged entry nozzle and its connection with the upper nozzle are easy to inhale air in continuous casting. Air aspiration leads to the oxidation of molten steel,nodule at the nozzle and serious continuous casting accidents. Argon injection inside the nozzle to prevent air aspiration,improper control of injecting argon is easy to cause defects in slab. Based on Bernoulli's theorem and law of conservation of mass,a velocity-mass model from the tundish to the mold is established,and the mechanism of air aspiration by the above components is discussed. Firstly,the influences of nozzle diameter,nozzle immersion depth,tundish level, slab width and casting speed on the ratio(AA/AP) of cross-sectional area at nozzle inlet to cross-sectional area at nozzle outlet are analyzed in both ideal and pressure loss cases. Then,the nozzle structure is optimized and the control model of argon flow is established. In order to prevent air aspiration into the submerged entry nozzle,the diameter of the nozzle should be reduced,the difference between the liquid level in the tundish and the nozzle immersion depth should be decreased,the casting velocity and the width of the cast slab should be increased. Among them,the nozzle diameter has the greatest influence to AA/AP. When the nozzle diameter increased by 10%,AA/AP increased from 2.15 to 2.62. The effect of slab width and casting speed was slightly lower than that of nozzle diameter. When the slab width and casting speed increased by 10%,AA/AP decreased from 2.15 to 1.96. The liquid level and immersion depth of tundish have the least influence on it. Based on the research results,the nozzle structure is optimized in accordance with the flow beams of liquid steel. Combined with the volume of vacuum area in the nozzle,the control model of argon blowing quantity is determined,which keeps the slightly positive pressure in the nozzle. The results provide a theoretical basis for reducing or even eliminating the air aspiration and controlling the argon flow rate,which is of great significance to the production of high-quality steel and energy saving and consumption reduction.
张伟阳, 程树森. 浸入式水口吸入空气机理及吹氩量控制模型[J]. 钢铁, 2022, 57(10): 110-119.
ZHANG Wei-yang, CHENG Shu-sen. Mechanism of air aspiration and control model of argon flow volume for submerged entry nozzle[J]. Iron and Steel, 2022, 57(10): 110-119.
[1] 邓勇, 杨利彬, 汪成义. 马钢低碳钢板坯高拉速连铸技术的应用[J]. 连铸, 2022(1): 72.(DENG Yong, YANG Li-bin, WANG Cheng-yi. Application of high-speed continuous casting technology for low carbon steel slab in Masteel[J]. Continuous Casting, 2022(1): 72.) [2] 罗衍昭, 何文远, 王少军,等. 2.05 m/min高拉速低碳钢FC控流结晶器的应用[J]. 连铸, 2022(4): 72.(LUO Yan-zhao, HE Wen-yuan, WANG Shao-jun,et al. Application of fluid control mold on low carbon steels at 2.05 m/min high speed slab continuous casting[J]. Continuous Casting, 2022(4): 72. ) [3] 张洪才, 印传磊, 郑力宁, 等. 浸入式水口结构对连铸大圆坯质量的影响[J]. 中国冶金, 2022, 32(9): 57.(ZHANG Hong-cai, YIN Chuan-lei, ZHENG Li-ning, et al. Influence of submerged nozzle structure on large-size continuous casting round billet quality[J]. China Metallurgy, 2022, 32(9): 57.) [4] 殷瑞钰,张福明,张寿荣,等. 钢铁冶金工程知识研究与展望[J]. 工程研究——跨学科视野中的工程,2019,11(5):438.(YIN Rui-yu,ZHANG Fu-ming,ZHANG Shou-rong,et al. Research on iron and steel metallurgical engineering knowledge[J]. Journal of Engineering Studies,2019,11(5):438.) [5] 杨明磊,程常桂,李阳,等. 连铸中间包水口机理及控制技术的发展[J].钢铁研究学报,2017,29(10):773.(YANG Ming-lei,CHENG Chang-gui,LI Yang,et al. Development of control technology and clogging mechanism for tundish nozzle in continuous casting[J]. Journal of Iron and Steel Research,2017,29(10):773.) [6] Savolainen J,Rousu A,Fabritius T,et al. Modelling of pressure distribution inside the SEN in a stopper-rod controlled system[J]. Steel Research International,2010,81(11):980. [7] Suzuki M,Yamaoka Y,Kubo N,et al. Oxidation of molten steel by the air permeated through a refractory tube[J]. ISIJ International,2007,42(3):248. [8] Gutiérrez E,Barreto J J,Garcia-Hernandez S,et al. Decrease of nozzle clogging through fluid flow control[J]. Metals,2020,10(11):1420. [9] SjÖstrÖm U,Burty M,Gaggioli A,et al. An experimental study of argon injection and aspiration of air into stopper rods in continuous casters[C]//Steelmaking Conference Proceedings. [S.L.]:Iron and Steel Society of AIME,1998:63. [10] Huang X,Thomas B G. Modeling of transient flow phenomena in continuous casting of steel[J]. Canadian Metallurgical Quarterly,1998(3/4): 197. [11] 陈志平,朱苗勇,文光华,等. 连铸铸坯浸入式水口吹氩工艺研究[J]. 钢铁,2009,44(7):28.(CHEN Zhi-ping,ZHU Miao-yong,WEN Guang-hua,et al. Effect of submerged entry nozzle argon blowing on slab quality[J]. Iron and Steel,2009,44(7):28.) [12] Bai H,Thomas B G. Effects of clogging,argon injection and casting conditions on flow rate and air aspiration in submerged entry nozzles[C]//Steelmaking Conference Proceedings. Warrendale: Iron and Steel Society,2000:183. [13] ZHANG J,LIU Q,YANG S,et al. Advances in ladle shroud as a functional device in tundish metallurgy:A review[J]. ISIJ International,2019,59(7):1167. [14] 龙山. 宽厚板连铸机铸坯质量的研究与改进[D]. 鞍山:辽宁科技大学, 2016.(LONG Shan. Research and Improvement of Slab Quality for Wide and Thick Plate Caster[D]. Anshan:University of Science and Technology Liaoning,2016.) [15] 刘颜彬, 唐海燕, 王凯民, 等. 水口结构对板坯结晶器液面流动行为的影响[J]. 连铸, 2022(3): 1.(LIU Yan-bin, TANG Hai-yan, WANG Kai-min, et al. Effect of submerged entry nozzle structures on liquid surface flow behavior of slab continuous casting mold[J]. Continuous Casting, 2022(3):1.) [16] 印传磊, 翟万里, 蒋栋初, 等. 42CrMo钢大尺寸夹杂物的来源与控制[J]. 中国冶金, 2021, 31(1): 36.(YIN Chuan-lei, ZHAI Wan-li, JANG Dong-chu,et al. Source and control of large-size inclusions in 42CrMo steel[J]. China Metallurgy, 2021, 31(1): 36.) [17] Salgado U D. Investigation of Particle Attraction by Steel/Refractory and Steel/Gas Interfaces and the Associated Relevance for Clogging in Casting Processes[D]. Leoben: University of Leoben,2018. [18] 杨晋. 连铸用浸入式水口和长水口的结构与材质探讨[J]. 中国金属通报, 2020(1):268.(YANG Jin. Discussion on structure and material of immersion nozzle and long nozzle for continuous casting[J]. China Metal Bulletin,2020(1):268.) [19] 时朋召. 厚铸坯连铸用结晶器浸入式水口结构优化与应用研究[D].赣州: 江西理工大学,2017.(SHI Peng-zhao. Research on Structure Optimization and Application of Mould Immersion Nozzle for Slab Continuous Casting[D]. Ganzhou: Jiangxi University of Science and Technology,2017.) [20] 王振兰,李小明. 连铸用功能耐火材料的发展[J]. 山东冶金,2008(1):8.(WANG Zhen-lan,LI Xiao-ming. Development of functional refractories for continuous casting[J]. Shandong Metallurgy,2008(1):8.) [21] Liu R,Thomas B G,Sengupta J,et al. Measurements of molten steel surface velocity and effect of stopper-rod movement on transient multiphase fluid flow in continuous casting[J]. Transactions of the Iron and Steel Institute of Japan,2014,54(10):2314. [22] Timmel K,Shevchenko N,RÖder M,et al. Visualization of liquid metal two-phase flows in a physical model of the continuous casting process of steel[J]. Metallurgical and Materials Transactions B,2015,46(2):700. [23] 张林杨. 含钛超低碳钢连铸浸入式水口的结瘤分析与控制[D]. 唐山:华北理工大学,2017.(ZHANG Lin-yang.The Analysis and Control of Submerged Nozzle Clogging for Ultra-low Carbon Steel Containing Titanium[D]. Tangshan:North China University of Science and Technology,2017.) [24] Klostermann J,Chaves H,Schwarze R. Investigation of the gas-liquid flow in a stopper rod controlled SEN[J]. Steel Research International,2007,78(8):595. [25] Yang H,Olia H,Thomas B G. Modeling air aspiration in steel continuous casting slide-gate nozzles[J]. Metals,2021,11(1):116. [26] 刘国齐,李红霞,袁磊,等. 连铸用浸入式水口防结瘤研究进展[J]. 耐火材料,2021,55(6):533.(LIU Guo-qi, LI Hong-xia,YUAN Lei. et al. Research progress on preventing nodulation of immersed nozzle for continuous casting[J]. Refractories,2021,55(6):533.) [27] Javurek M,Thumfart M,Wincor R. Investigations on flow pattern and pressure inside SEN below stopper rod[J]. Steel Research International,2010,81(8):668. [28] 刘中秋,李宝宽,阮晓明,等. 一种连铸结晶器浸入式水口吹氩控制方法:中国,CN109047695A[P].2018-12-21.(LIU Zhong-qiu,LI Bao-kuan,RUAN Xiao-ming,et al. The Invention Relates to an Immersion Nozzle Blowing Argon Control Method for Continuous Casting Mold:China,CN109047695A[P].2018-12-21.)
2022, Vol. 57 
