电渣重熔过程电磁场和温度场数值模拟

Numerical Simulation of Electromagnetic Field and Temperature Field of ESR

建立了考虑电流集肤效应的三维电渣重熔电磁场和温度场数学模型,并采用电磁场和金属熔池形貌测量方法分别验证了数学模型的准确性,分析了电流频率和渣池厚度对电渣重熔过程电流密度、磁感应强度、电磁力、焦耳热、温度、熔池深度的影响规律.结果表明:随着电流频率增加,电极和钢锭表面电流集肤效应明显,渣池内部电流分布基本不变;电渣重熔系统内最大焦耳热位于平底电极与渣池接触角部,然而高温区位于渣池内部电极下方靠近渣金界面处.当渣池厚度从0.15 m增加到0.21 m,渣池中心轴线上最高温度从1 826℃降低到1 721℃,金属熔池深度从0.22 m降低到0.16 m.

3D finite element models for both the magnetic field and temperature field of electroslag remelting （ESR） system were developed and validated by the experimental measurements of magnetic flux density and melt pool profile. The effects of current frequency and slag cap thickness on the current density, magnetic flux density, electromagnetic force, joule heat, temperature field and melt pool depth were investigated, respectively. The results showed that with the increase of current frequency, the skin effect of current on the external surfaces of electrode and ingot is more significant, but the current frequency has no effect on the current density distribution in slag cap. The maximum joule heat zone is located on the comer of contact position between flat head electrode and slag. However, the high temperature zone is located in the slag cap below the electrode head and near the slag/melt interface. With the increase of slag cap thickness from 0. 15 m to 0. 21 m, the highest temperature in the axis of slag cap decreases from 1 826 ℃ to 1 721℃, and the melt pool depth decreases linearly from 0. 22 m to 0. 16 m.