小方坯连铸末端电磁搅拌综合控制模型

Collective Control Model of Final Electromagnetic Stirring in Billet Continuous Casting

为解决连铸生产过程中因拉速、过热度等工艺条件频繁波动而导致铸坯凝固末端发生变化,使得末端电磁搅拌(FEMS)难以产生稳定良好的搅拌效果的问题,提出一种FEMS综合控制模型。此模型通过在线凝固传热模型计算得到FEMS安装处的坯壳厚度SF,然后采用基于目标坯壳厚度控制的二冷模型调节二冷水量使SF保持稳定,并根据不同的SF调节FEMS的电流和频率,使FEMS的使用效果达到最优值。采用射钉试验验证了数学模型的计算精度。计算机模拟及现场应用的结果表明,在160mm×160mm小方坯连铸机上,此综合控制模型能够使FEMS安装处的坯壳厚度保持稳定,目标坯壳厚度设定为52mm时,有效提高铸坯的内部质量。

The frequent fluctuations of technical parameter,such as casting speed and superheat,can cause the fluctuations of solidification end location in billet,which weakened the effect of final electromagnetic stirring（FEMS）.A new collective control model of FEMS was established to improve the effect of FEMS.The shell thickness at the location of FEMS（SF） was calculated through a real-time heat transfer and solidification model.The fluctuations of shell thickness at the location of FEMS was be reduced through using a secondary cooling model based on target shell thickness controlling method,and the current and frequency was also adjusted according to the variations of SF at the same time.Nail-shooting was used to validate the mathematic model.The results of computer simulation and industrial trails shows that this model can stabilize the shell thickness at the location of FEMS and improve the inside quality of billet when it was applied in a 160 mm×160 mm billet casting machine with a target shell thickness which was set to 52 mm.