宽厚板坯连铸结晶器内坯壳-铜板界面热行为研究.pdfVIP

∗ 宽厚板坯连铸结晶器内坯壳-铜板界面热行为研究 蔡兆镇 朱苗勇 (东北大学材料与冶金学院，沈阳 110004) 摘 要 根据结晶器内初凝坯壳热收缩量与结晶器铜板热面间的位移关系、保护渣的液- 固状态及厚度分布、铸坯 表面和铜板热面的温度分布以及气隙的动态变化等建立了坯壳-铜板界面热流模型，并在此基础上，通过将该模型 嵌入至结晶器内坯壳凝固过程二维瞬态热/力耦合有限元模型，研究分析了国内某钢厂实际宽厚板坯连铸工况下结 晶器内某碳钢凝固过程坯壳角部区域气隙、保护渣厚度分布的规律和对应区域热流变化的特征。 关键词 宽厚板坯连铸 结晶器 保护渣 热行为 Simulation of Thermal Behavior of Shell-Mold Interface during Steel Solidification in Wide and Thick Slab Continuous Casting Mold Cai Zhaozhen, Zhu Miaoyong (School of Materials and Metallurgy, Northeastern University, Shenyang,110004) Abstract According to the displacement between solidifying shell surface and the mold hot face as solidification contraction, the liquid-solid structure and distribution of mold flux, and the temperature distribution of slab surface and mold hot face, one heat flux model of shell-mold interface was established. Based on this, by the means of implanting the model into a 2D transient thermal-mechanical finite element model of shell solidification in mold, the thermal behavior of shell-mold interface which includes air and mold flux distribution law and heat flux changing character of shell corner during carbon steel solidification in the wide and thick slab mold under the practical continuous casting conditions were investigated. Key words wide and thick slab continuous casting, mold, mold flux, thermal behavior 1 引言 宽厚板坯连铸具有断面大、拉速低、坯壳-结晶器界面传热行为复杂等特点，易引发初凝坯壳在结晶器 内不均匀生长。结晶器内坯壳与铜板间的界面传热行为主要由因保护渣凝固产生的结晶器-保护渣界面热阻、 保护渣的状态和厚度分布及对应传热特性、坯壳凝固收缩引起的坯壳-保护渣间气隙分布等共同决定。受检 测条件的限制，目前对结晶器内该界面热行为的研究主要采用数值模拟方法，并建立了多个有代表性的界面 传热模型[1～8]，但绝大多数的做法是将渣道内的保护渣厚度处理为定值或仅沿结晶器高度方向发生变化。而 在实际连铸过程中，保护渣在结晶器内沿周向和高度方向的分布并不均匀。为此，本文利用根据连铸坯在结 晶器内凝固收缩量与结晶器内表面的位移关系、保护渣的液-固状态及厚度分布、铸坯表面和铜板热面的温 度分布以及气隙的动态变化等建立坯壳-铜板界面热流模型，并通过