板坯凝固过程夹杂物运动行为

Inclusion Behavior During Slab Solidification

利用数值模拟的方法对结晶器中的钢液流动、传热凝固以及夹杂物运动进行了耦合计算。研究表明,钢液对结晶器窄面的冲击严重,导致在冲击点附近的凝固坯壳较薄。夹杂物越大、拉速越小,越有利于夹杂物上浮至自由液面。小颗粒夹杂在结晶器中并不能被有效去除。对于粒径为50μm的夹杂物,当拉速为1 m/min时其上浮率仅为46%,有37%的夹杂物被凝固坯壳捕捉。夹杂物被坯壳捕捉的位置多集中在窄面和宽面靠近窄面处,而在水口下方被捕捉的夹杂物数量则较少。

A numerical simulation method was used to study the turbulent flow, heat transfer coupled with the motten steel solidification and inclusion movement in mold. The results show that due to the strong jet impingement on the narrow face in mold, solid shell near the impingement point is very thin. Inclusions tend to float up to the free surface at low casting speeds or when their sizes are large. Small inclusions can not be effectively removed in mold. For inclusions of 50 μm, the removal rate is only 46% when the casting speed is 1 m/min, and 37% of the inclusions are trapped in the solid shell. Most of the inclusions trapped in the solid shell are located at the narrow face and the wide face near the narrow side, but few are located under the nozzle.