钢连铸圆坯结晶器锥度数值模拟优化

Numerical Optimization of Round Mould Taper for Continuous Casting Steel Slab

基于有限元软件ANSYS,建立了二维连铸圆形结晶器内钢水凝固传热及弹塑性应力有限元瞬态分析模型。从物理现象的本质特征出发,钢坯传热边界采用与气隙相关的热流密度修正函数,建立与温度相关的热物性参数、力学性能和屈服函数。在二次开发的基础上,利用多场间接耦合的方式,对4种圆坯的凝固收缩变形过程进行数值模拟研究。模拟结果显示,钢种、碳含量和拉坯速度对铸坯边界凝固收缩影响显著。在结晶器高度方向上,结晶器锥度为明显的分段抛物线连续曲线,在结晶器出口处,4种圆坯边界凝固收缩量分别达到2.20mm、3.41mm、3.79mm和4.29mm,以铸坯边界的凝固收缩曲线和结晶器基本设计原则为依据,完成抛物线型连续锥度结晶器型腔的统一设计。

Two-dimensional transient FEM (finite element model) for heat transfer and elastic-plastic stress of liquid steel solidification in continuous casting round mould was established based on the ANSYS software,in which from the essential phenomena in the mould,a gas gap-dependent heat transfer condition were introduced to modify the heat flux function,and the variation of material thermal properties,mechanical properties as well as yield function with temperature were considered. Based on secondary development for the model,using multi-field indirect coupled method,the solidification shrinkage process of four kinds of round steel billets were simulated. The results reveal that solidifications shrinkage is closely related to steel types,carbon content and drawing velocity. Mould taper exhibits continuous parabolic curves along the height of the mould. At the outlet of mould,the solidification shrinkage rates of four round billets make 2.2 mm,3.41mm,3.79 mm and 4.30 mm,respectively. Based on the solidification shrinkage curves of round billets and basic principle of mould design,the universal parabolic taper for round mould is completed.