Feeding Sequence of Lining Material
Correct feeding sequence can not only improve melting efficiency, save power consumption, but also stabilize the quality of molten iron.
The feeding sequence should always be the same. Initially, silicon carbide should be added (if instead of silicon carbide, it should be replaced by a carburizer). This is not only to make it known that it takes time for silicon to be evenly distributed in molten iron, but also to prevent damage to furnace lining due to impact when adding metal materials.
Secondly, add scrap steel to 1 / 3 of the furnace height, and then heat to the temperature above the magnetic transition point (critical temperature or Curie point, at or above this temperature, the magnetic materials become paramagnetic. That is to say, the magnetic field coupling produced by the magnetic axis of the atom along the induction coil).
At the end of this phenomenon, first add a proper amount of low melting point material to form a molten pool as soon as possible to maintain the maximum input power, then add scrap steel and carburizer, following pig iron, and then foundry returns and other materials.
However, the above standards will be changed when drying (or sintering) the furnace. At this time, it is better to use 100% recycled materials.
Generally speaking, if a large amount of recycled materials or other materials with high CE value are initially added in induction melting, at least one of the following phenomena will occur according to experience: the carburizer is wrapped by slag generated from the recycled materials and cannot be absorbed by molten iron. Or the waste steel added later needs extremely long heat preservation time, otherwise the carburizer floats on the surface of the molten iron and cannot be absorbed into the molten iron, so that the absorption rate of the carburizer is reduced and the composition is not stable.