Solidification Structure and Compactness Degree of Central Equiaxed Grain Zone in Continuous Casting Billet Using Cellular Automaton-Finite Element Method
Solidification Structure and Compactness Degree of Central Equiaxed Grain Zone in Continuous Casting Billet Using Cellular Automaton-Finite Element Method
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DOI：
10.2355/isijinternational.52.1301
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发表时间：
2012-07
影响因子：
1.8
通讯作者：
Zibing Hou;F. Jiang;G. Cheng
中科院分区：
文献类型：
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作者：
Zibing Hou;F. Jiang;G. Cheng
建立了元胞自动机-有限元（CAFE）耦合模型，分析了高碳钢连铸坯凝固组织的演变和中心等轴晶区的致密程度。首先比较了模拟凝固组织与实际凝固组织在无MEMS（模具电磁搅拌）、有MEMS和MEMS加强化冷却三种不同条件下的差异。结果表明，该模型能较好地模拟实际凝固组织。然后，利用该模型对不同过热度和浇注速度下的凝固组织进行了模拟。结果表明：等轴晶带宽度随过热度的降低而增大，随浇注速度的降低而减小；本研究还采用不同条件下同一区域内的粒数来评价中央等轴晶粒带的致密程度。结果表明，采用MEMS可明显提高坯料中心等轴晶区的致密度，采用MEMS加强化冷却可进一步提高坯料中心等轴晶区的致密度。此外，降低浇注速度也会增大。但随着过热度的降低，中心等轴晶区的致密度降低。坯料中心等轴晶区的致密程度与中心凝固时间密切相关，随着中心凝固时间的增加而减小。
A Cellular Automaton-Finite Element (CAFE) coupling model was developed to analyze the evolution of solidification structure of high-carbon steel continuous casting billet and the compactness degree of central equiaxed grain zone. Comparison between the simulated and actual solidification structure was first made under three different conditions, i.e., without MEMS (mould electromagnetic stirring), with MEMS and with MEMS plus intensive cooling. It is indicated that the model can provide a good simulation of the actual solidification structure. Thereafter, the model was used to simulate the solidification structure under different superheats and casting speeds. It is shown that the width of equiaxed grain zone increases with the decrease of the superheat, and decreases with the decrease of the casting speed. The compactness degree of central equiaxed grain zone is also evaluated by the grain number in the same area under different conditions in this study. It is demonstrated that the compactness degree of central equiaxed grain zone in the billet is increased obviously when the MEMS is applied, and is further increased with MEMS plus intensive cooling. In addition, it is also increased when decreasing the casting speed. However, the compactness degree of central equiaxed grain zone is decreased when decreasing the superheat. Moreover, it is found that the compactness degree of central equiaxed grain zone in the billet is closely related to the centre solidification time, i.e., it decreases with the increase of the centre solidification time.