Tundish plaster

Tundish plaster is a specialised refractory coating applied to the inner surface of a tundish, which serves as an intermediate vessel in continuous steel casting. The primary purpose of tundish plaster is to provide thermal insulation, protect the tundish lining, and ensure smooth, clean steel flow from the ladle to the mold. It plays a vital role in enhancing steel quality, reducing refractory wear, and improving casting efficiency.

Typically composed of refractory materials such as magnesite, alumina, silica, and various bonding agents, tundish plaster is designed to withstand the extreme temperatures and chemical environments present during molten steel handling. It is applied as a slurry, which is then dried and sometimes sintered to form a uniform, insulating layer over the tundish’s working lining. This plaster layer acts as a sacrificial coating, which can be easily removed or replaced between casting sequences, extending the service life of the permanent refractory lining.

One of the most important functions of tundish plaster is thermal insulation. By reducing heat loss through the tundish walls, the plaster helps maintain the temperature of the molten steel, ensuring a stable casting process and reducing the risk of steel solidification within the tundish. This thermal efficiency is crucial for producing uniform, defect-free billets or slabs.

In addition to insulation, tundish plaster also prevents steel re-oxidation and contamination. By covering the tundish surface, it minimises contact between molten steel and the base refractory materials, which might otherwise react and introduce unwanted elements into the steel. A smooth, even plaster coating promotes laminar flow and reduces turbulence, helping to control the movement of inclusions and promoting better steel cleanliness.