How to properly install and repair the coil grout of an Induction furnace

1. When repairing localized damage to the coil grout, remove all debris from the coating and then apply the necessary repair material. Note that after repair, the surface should be smooth, flat, and concentric.

2. When applying a new coil coating, first hang a plumb line in the center of the furnace to check if the coil's installation position is concentric with the furnace. When applying the coil coating, ensure it is embedded between the coil turns, with a coating thickness of approximately 8-10 mm. The surface should be smooth and flat.

When removing the old furnace lining using an ejector mechanism, the coating should be made into a smooth, flat inner surface in an inverted cone shape, wider at the top and narrower at the bottom. The lower coating thickness can be 12-15 mm, or refer to the furnace manufacturer's specifications. The slope should be minimized within 300 mm below the furnace nozzle to prevent gaps between the nozzle and the hot surface material during use, which could cause molten iron leakage.

3. Minimize the gaps or protrusions between the bottom/top turns of the coil and the corresponding bottom/upper support structure of the electric furnace (such as the pouring gate). The aim is to create a smooth, integral cylindrical surface between the coil grout and the furnace's bottom/upper support structure, allowing the furnace lining to expand and contract freely on this smooth surface during heating or cooling. This prevents excessive stress between the furnace lining and the aforementioned protrusions or gaps during expansion and contraction, which could lead to cracks in the furnace lining.

4. After applying the coating, roughen the surface with a wire brush to facilitate drying.

5. New coil grouts or repairs to larger areas of coil coating should be allowed at least 24 hours of natural drying; small-area coil coating repairs should also be allowed at least 6 hours of natural drying.

Coil Grout

What is the induction furnace?

An induction furnace is an electrical furnace in which the heat is applied by induction heating of metal. Induction furnace capacities range from less than one kilogram to one hundred tons, and are used to melt iron and steel, copper, aluminum, and precious metals.

What are the disadvantages of induction furnace?

Nonetheless, the disadvantages of induction furnaces are high quality – more expensive scrap charging requirement, high investment cost for installation, lower melting capacities (below 15 tonnes per hour), and heat losses in the water-cooled induction coil (European Commission 2005).

What is the difference between electric furnace and induction furnace?

The IF (Induction Furnace) has higher thermal efficiency and can rapidly heat the charge materials. In contrast, the EAF (Electric Arc Furnace) loses a significant amount of arc heat through the furnace cover and walls.

What are the two types of induction furnaces?

Induction furnaces are of two types: cored furnace and coreless furnace. Cored furnaces are used almost exclusively as holding furnaces. In cored furnace the electromagnetic field heats the metal between two coils. Coreless furnaces heat the metal via an external primary coil.