Numerical Simulation of In-mold Electromagnetic Stirring on Slide Gate Caused Bias Flow and Solidification in Slab Continuous Casting

A mathematical model coupled with electromagnetic field, flow, heat transfer and solidification has been developed to simulate the bias flow caused by slide gate under different slide-gate opening rates, EMS currents and casting speeds. Through comparing the magnetic flux density and flow field with measured results, the reliability of mathematical model is proved. The symmetric index, variance of solidified shell thickness have been introduced to judge the symmetry of flow field and uniformity of solidified shell, respectively. The results show that bias flow phenomenon has happened when the slide-gate opening rate is less than 100%, the deviated direction is opposite to the opening direction of slide gate. As the slide gate opening rate decreases, the symmetry of flow field and uniformity of solidified shell decrease. Increasing the EMS current and decreasing the casting speed, the symmetry of flow field caused by slide gate increases, but it can not eliminate completely, while the uniformity of solidified shell increases firstly and then decreases. There exists an optimal EMS to balance the symmetry of flow field and uniformity of solidified shell.