Tundish permanent linings mainly play the role of security protection and heat insulation effect. At present, tundish permanent layer is casting by Al₂O₃-SiO₂refractory castables.

　　What are the damage causes of tundish permanent layer?

　　1. The lack of thermal shock resistance

　　In uses, either cracking and spalling caused by fluctuating temperature or the slag penetrates into crack, slag is inlaid in permanent layer for castables, resulting tilting tundish is difficult.

　　2. Poorly slag penetration resistance

　　In use process, the slag penetrates into permanent layer for castables to accelerate sintering, leading to spalling caused by fluctuating temperature.

　　3. Poor high temperature performance

　　Refractory castables are perhaps sintered under lower temperature, thus leading to spalling of sinter layer near the coating layer.

　　4. The others

　　Sometimes the slag has strong erosion, working layer and permanent layer for castables suffered erosion one after another, thus reducing service life of the tundish.

　　In summary, well resolving these problems that concerning slag penetration, thermal shock resistance and erosion resistance is the sticking point to improve the application of the tundish castables.