Induction Furnace Coil Coat & Patching Material

Coil coat (coil grout) is a castable applied over the induction coil before the working lining is rammed. It protects the coil insulation and conducts heat away from it. Without it, metal fins penetrating from a worn lining can reach the coil directly, which is both a furnace failure and a serious safety event. Patching material is a separate product used to repair worn areas of the lining between full relines.

Choose on what governs your application. CUMI SUPER SHIELD is 94% Al₂O₃ min and rated to 1800°C, so specify it where peak service temperature governs. CUMI SHIELD is 87-90% Al₂O₃ to 1700°C and develops 550 kg/cm² min after firing at 1450°C, so specify it where fired strength matters. Saint-Gobain HeatKing CA 337 is a fused alumina grout offering significantly higher dielectric strength than silicate-bonded grouts, for when coil protection is the priority.

Coil coat goes on before the lining, against the coil, and stays there for the life of the furnace. Patching material repairs and upgrades worn areas of an existing alumina-based lining between full relines. HeatKing PA 748 (83% Al₂O₃, 17 MPa min fired at 1250°C) is also used as a primer or undercoat with alumina-based melting refractories, so it serves both a repair and a preparation role.

Yes. We are an authorised CUMI dealer and supply SUPER SHIELD and SHIELD, alongside the Saint-Gobain HeatKing range including CA 337 fused alumina coil coat and PA 748 patching material. Tell us your furnace size, melt chemistry and whether dielectric protection or peak temperature is your priority, and our engineers will match the grade and quantity.