Effect of electromagnetic induction coil position on feeding effect in steel ingot

The relationship between the feeding ability of the riser and the shrinkage and porosity is always a hot investigation topic, and the interior shrinkage and porosity of the ingot is the common defect met by industries. The work on the effect of Electromagnetic Feeding Riser (EFR) on ingot solidification is approached via the interpretative of the electromagnetic heat efficiency, temperature field, and Niyama criteria. The results show that the heating effect is better when the induction coil is at L = 0 mm and the heat efficiency rapidly reduces with the induction coil away from the riser, from the view of magnetic field. An obvious improvement in the solidification process is the application of EFR from the view of temperature field. Then, the Niyama criterion was defined as 1.1 through the experiment and simulation. Electromagnetic feeding starts to restrain the appearance of the shrinkage and porosity when L = 0 mm and D = 60 mm, where the effective Joule heat generated by the induction coil occupies about 75% of the energy dissipated in the riser solidification process, at least. The better feeding effect can be obtained at L = 0 mm and D = 40 mm in consideration of the thickness of the insulation board.