Tundish Permanent Layer Castable

Tundish permanent layer castables are an important component of the refractory material of the tundish. Although they are not the working layer and do not directly contact the molten steel, their use environment is still relatively harsh. The temperature of the tundish rises sharply when it is baked and receives molten steel, and the temperature drops rapidly after the continuous casting is completed and the tundish is turned over. Therefore, the castable is repeatedly subjected to thermal stress caused by rapid cooling and heating. In the injection area where the molten steel stays the longest, the working layer at the slag line will be severely eroded, and the permanent layer castable will also be corroded by slag; when the coating material of the working lining is constructed, the castable will be "corroded by water" by the magnesium coating material with a water content of about 25%. In addition, in the injection area and the pouring hole, the magnesium coating material is easy to sinter with the castable, making it difficult to disassemble the coating material. In the case of manual removal of the coating material, crane hoisting, etc., the permanent layer castable will cause mechanical damage. Under the long-term and repeated thermal stress, the castable will produce cracks. As the use time increases, the cracks gradually expand, and the castable will produce peeling and other damage. As the damage of the permanent layer castable intensifies, if the permanent layer castable reaches its service life, the permanent layer castable will be completely removed and a new castable will be constructed, and sometimes the permanent layer castable is only partially damaged.