Abstract: 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 corner 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15m to 021m， the highest temperature in the axis of slag cap decreases from 1826℃ to 1721℃， and the melt pool depth decreases linearly from 022m to 016m.

Key words: electroslag remelting(ESR), electromagnetic field, temperature field, skin effect, numerical simulation