Cast iron insulating coverant is primarily used to extend the solidification time of metal in the riser and serves as both an insulator and slag barrier. The optimal time for its addition is between when the steel reaches 2/3 of the riser and the pouring stops, or it can be added after pouring has ceased. The entire addition process must be completed before the riser's surface film forms.

Using cast iron insulating agent can effectively reduce the heat loss of molten metal, extend the solidification time of risers, enhance the feeding effect of risers, and also boasts the advantages of simple and convenient use, as well as low addition amount.