利用有限元模型对板坯倒角结晶器锥度的优化

Optimization of Slab Chamfered Mold Taper Design by Using FEM

为解决某厂板坯连铸机倒角结晶器在倒角部位经常出现缝隙，进而导致连铸坯发生裂纹缺陷的问题，利用有限元软件ANSYS对板坯倒角结晶器内钢液的凝固过程进行热力耦合数值模拟。分析结果表明，随着连铸坯在结晶器内向下移动，连铸坯和结晶器壁界面处的气隙宽度并非线性增加，而是在结晶器上部气隙宽度增加速度较快，在结晶器下部气隙宽度增加速度变缓。采用传统单锥度结晶器并不能有效弥补坯壳的收缩变形，特别在结晶器上部区域，通常采用的0．9％-1．2％／m的锥度偏小，难以抑制角部气隙生长，使角部坯壳生长受阻。根据模型计算结果优化后，将倒角结晶器窄面锥度变为渐变式，大致简化为2段：第1段是从弯月面附近到距上口0．35m处，采用较大锥度，平均锥度为2．16％；第2段是从距结晶器上口0．35m到结晶器出口处，采用较小锥度，平均锥度为1．31％。

In order to solve the problem of the gap appearing frequently in the chamfer position of slab continuous caster chamfered mold which resulted in crack problem of slabs, thermo-mechanical coupled numerical simulation of solidification process of molten steel in the slab chamfered mold was performed by using finite element software ANSYS. The results showed that the width of air gap between slab and mold wall interface did not increased linearly, instead, the width increased quickly in the upper part of the mold and slowly in the lower part with slab moving downward in the mold. The slab shell shrinkage and deformation could not be compensated effectively by using traditional single taper mold. Especially in the upper mold, the small taper, 0. 9% ~ 1.2%/m, made it difficult to restrain the growth of the corner gap which inhibited the growth of the shell in the comer. According to the calculation results of the model, the taper of the narrow face of the chamfered mold was gradual, roughly simplified into two sections. The first section was the distance 0.35 m from near the meniscus level. In this section, the larger taper was adopted and the average taper was 2. 16%. The second section was from the distance 0. 35 m from the meniscus level to the mold exit. In this section, the smaller taper was adopted and the average taper was 1.31%.