摘要
熔池中的流动是影响电子束冷床炉熔铸铸锭质量的一个非常重要因素。本研究通过建立三维非稳态模型研究电子束冷床炉熔铸钛扁锭过程中的流动及熔池形态变化,采用混合欧拉-拉格朗日算法模拟非稳态凝固过程。通过设置一系列的能量输入策略,分析了不同电子枪功率下的结晶器内的非对称流动特征、温度场及熔池形态变化。研究结果表明流动及传热共同导致了非对称熔池的形成。钛液从溢流口进入结晶器后,一部分向下流动侵蚀凝固坯壳,一部分由于不同温度的密度差受到的浮力返回了液面。凝固坯壳被侵蚀后变薄影响对称性,返回液面的钛液改变了液面温度,影响了能量吸收效率及液面温度分布。通过优化电子枪的能量输入策略,可以有效的改善熔池的对称性,避免因熔池不对称导致熔铸缺陷的出现。
Fluid flow in the solidifying pool plays an important role for the casting quality in electron beam cold hearth re-melting(EBCHR or EB Re-melting)process.A three-dimensional unsteady state model was built to describe the fluid flow and the sump evolution during the EBCHR process of titanium slab casting.The Mixed Lagrange and Euler(MiLE)approach was employed to investigate the unsteady state casting process.A set of asymmetrical EB power input was tested in the model to demonstrate the characteristic of the fluid flow,temperature distribution and sump profile.The results show that the asymmetrical sump is induced by the coupling of fluid flow and heat transfer within the asymmetrical mold.Part of the inlet fluid infiltrates the solidifying shell,and part of the inlet fluid rebounds to the melt surface.The infiltration of downward inlet flow reduces the solidifying shell,while the rebound of upward inlet flow enforces the heat absorption along the melt surface.The sump asymmetry can be adjusted with optimization of the EB power density.
作者
许耀平
陈其朋
刘源
史亚明
秦铁昌
沈厚发
Xu Yaoping;Chen Qipeng;Liu Yuan;Shi Yaming;Qin Tiechang;Shen Houfa(Key Laboratory for Advanced Materials Processing Technology,Ministry of Education,School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China;Kunming Iron and Steel Co.,Ltd,Kunming 651206,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2020年第11期3761-3768,共8页
Rare Metal Materials and Engineering
基金
National Key R&D Program of China(2016YFB0301202)。
关键词
电子束冷床炉
流动
熔池变化
非对称温度场
electron beam cold hearth re-melting
fluid flow
sump evolution
asymmetry temperature distribution
