无氟CaO-Al_(2)O_(3)-TiO_(2)基高钛钢保护渣结晶行为及渣膜可视化  

Crystallization behavior and visualization of fluorine-free CaO-Al_(2)O_(3)-TiO_(2) based mold flux for high titanium steel

作　　者：朴占龙 王雁 胡桂渊 朱立光 张彩军 王杏娟 孙立根 PIAO Zhanlong;WANG Yan;HU Guiyuan;ZHU Liguang;ZHANG Caijun;WANG Xingjuan;SUN Ligen(School of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,Hebei,China;Hebei High Quality Steel Continuous Casting Technology Innovation Center,Tangshan 063210,Hebei,China;School of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,Hebei,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210 [2]河北省高品质钢连铸技术创新中心,河北唐山063210 [3]河北科技大学材料科学与工程学院,河北石家庄050018

出　　处：《钢铁》2024年第10期55-63,共9页Iron and Steel

基　　金：国家自然科学基金青年基金资助项目(52304350);国家自然科学基金资助项目(52374335,52174313);河北省自然科学基金资助项目(E2021209037,E2021209083);中央引导地方科技发展资金资助项目(236Z1017G);河北省基本科研业务费资助项目(JST2022002);唐山市科技计划资助项目(23130204E)。

摘　　要：高钛钢在浇铸过程中,结晶器内存在钢-渣界面反应现象,导致铸坯表面产生裂纹和缺陷,严重时甚至发生漏钢。为解决高钛钢钢-渣界面反应现象,开发出CaO-Al_(2)O_(3)-TiO_(2)基高钛钢保护渣,该渣系能够抑制钢-渣界面反应的发生,但其与CaO-Al_(2)O_(3)系保护渣主体成分都含有CaO和Al_(2)O_(3),存在结晶能力强的可能,易导致润滑效果差。为此,深入探究CaO-Al_(2)O_(3)-TiO_(2)基高钛钢保护渣结晶行为,并利用DHTT(双丝设备)设备模拟结晶器内渣膜温度场而实现渣膜可视化研究,通过SEM-EDS解析渣膜矿相结构,为CaO-Al_(2)O_(3)-TiO_(2)基保护渣的应用提供理论指导。研究结果表明,CaO-Al_(2)O_(3)-TiO_(2)基保护渣临界冷却速率为10℃/s,开始结晶温度为1350℃,孕育时间为345 s。高温区析出大量交错互锁的亮色条状钙钛矿晶体,低温区析出细小的钙钛矿和BaAl_(2)O_(4)。在结晶器弯月面至结晶器出口处,渣膜中液态渣膜逐渐减薄,结晶态渣膜逐渐增厚,但结晶器出口处仍存在液态渣膜。在结晶器内渣膜一直保持液态渣膜、结晶态渣膜、玻璃态渣膜3层稳定结构,这说明在浇铸高钛钢过程中,CaO-Al_(2)O_(3)-TiO_(2)基保护渣能够发挥控制传热和润滑铸坯的作用。The steel-slag interface reaction often occurs in the mold when casting the high titanium steel,resulting in cracks and defects on the surface of the billet,and even the steel breakout will happen in the serious cases.The CaO-Al_(2)O_(3)-TiO_(2) based mold flux for high titanium steel was exploited for solving the phenomenon of the steel-slag interface reaction,which could inhibit the occurrence of the reaction.But the main component of CaO-Al_(2)O_(3)-TiO_(2) based mold flux and CaO-Al_(2)O_(3) based mold flux are CaO and Al_(2)O_(3),it means that the mold flux may have a strong crystallization ability and easy to result in difficultly casting the high titanium steel.Thus,the crystallization behavior of CaO-Al_(2)O_(3)-TiO_(2) based mold flux was deeply explored.The DHTT equipment was used to simulate the temperature filed of slag films in the mold for realizing the visualization,and the SEM-EDS was used to analyze the microstructure of slag films,the theoretical guidance for the application of CaO-Al_(2)O_(3)-TiO_(2) based mold flux was provided.The results showed that the critical cooling rate is 10℃/s,the start crystallization temperature is 1350℃,incubation time is 345s.The large amounts of the bright and interlocking striped perovskite is precipitated in the high temperature zone,and the fine perovskite and BaAl_(2)O_(4) are precipitated in the low temperature zone.The thickness of liquid slag film and crystallization slag film are respectively decreased and increased among the meniscus and outlet of the mold,but the liquid slag film still exists at the mold outlet.The liquid slag film,crystallization slag film and glass slag film are always exist between the hot surface mold and initial shell,which indicates that CaO-Al_(2)O_(3)-TiO_(2)based mold flux can play the role of controlling heat transfer and lubrication in the process of casting high titanium steel.

关 键 词：高钛钢 临界冷却速率 孕育时间 渣膜结构 可视化 

分 类 号：TF777[冶金工程—钢铁冶金]