高频磁场下连铸保护渣润滑行为数学模型

为了研究高频磁场下连铸保护渣在结晶器内的润滑状况,建立了高频磁场下连铸保护渣润滑行为数学模型,并应用该数学模型研究了初始凝固时磁场作用下渣道宽度、弯月面高度、渣道动压、渣耗、摩擦力等因素对保护渣润滑行为的影响。结果发现,磁场的作用拓宽了保护渣渣道宽度,增大了弯月面高度,使保护渣渣道入口及出口宽度增加,使初始凝固点下移,改善了传热条件有利于铸坯表面质量提升;磁场的作用减小了因结晶器振动而产生的正压和负压,并且正、负压都是随着磁场强度的增大而减小,但磁场强度存在一个最佳值;磁场的作用增大了渣耗量,改善了铸坯与结晶器之间的润滑;铸坯与结晶器之间摩擦力随着磁场强度的增大而减小,当磁场强度为40 mT时,总摩擦力减小趋于平缓,因此磁场强度为40 mT左右时对减小摩擦力的作用效果较好。

Mathematical model of lubrication behavior of continuous castingprotective slag under high frequency magnetic field

A mathematical model was established to study the lubrication behavior of continuous casting protective slag in the mold under high frequency magnetic field. This mathematical model was used to study the influence of the slag channel width, meniscus height， dynamic channel pressure, slag consumption， friction force and other factors on the lubrication behavior of the protective slag during initial solidification. The results showed that the application of the magnetic field increases the width of slag channel， the height of the meniscus, as well as the width at the entrance and exit of slag channel， lowers the initial solidification point， and improves the heat transfer conditions in favor of the surface quality of the slab. The application of the magnetic field reduces the positive pressure and negative pressure generated by the vibration of the mold， and the positive and negative pressures decrease with the increase of the magnetic field intensity， but the magnetic field intensity has an optimal value. The application of the magnetic field increases the slag consumption and improves the lubrication between the slab and the mold. The friction force between the slab and the mold decreases with increasing the magnetic field intensity. When the magnetic field intensity is 40mT， the total frictional force tends to be unchanged. Therefore， the reasonable magnetic field intensity for reducing the friction is about 40mT.