Requirements of Pure Water Quality of Steel Water for Continuous Casting of Thin Slab Billet
Continuous casting is a key technological process in modern steelmaking. The quality of steel water directly affects the quality of products. In terms of thin steel slab billet continuous casting, the quality of steel water not only directly affects the quality of thin slab finished products, but also affects the seamless production of thin slab continuous casting. Therefore, for thin slab billet continuous casting, the requirements for the quality of steel water are extremely strict.
1. Requirements for Chemical Component:
In order to improve the plasticity of steel water, reduce feeding and reduce the oscillation of molten steel in thin slab continuous casting, it is necessary to add some chemical components to the steel water, such as calcium, magnesium, chloride, sulfur, manganese, aluminum and other micro-combined components. Among them, calcium, magnesium and chloride are the main components.
Calcium has a great influence on the surface properties, toughness and plasticity of thin slab billet. It affects the surface quality of thin slab billet and the thickness and bead shape of thin slab billet. In general, when the Ca content of steel water is between 0.03%-0.20%, the thin slab surface can get the best conditions. In thin slab continuous casting, Ca should not be too high, too low or too uneven.
Magnesium has a great influence on the surface, toughness and plasticity of steel, so it can be used to control the sliding surface quality, decrease the degree of surface cracking, reduce the center line segregation and improve the center line metallographic structure of thin slab continuous casting. The content of Mg in thin strip and medium strip steel billets is usually 0.030%-0.120%.
The content of chloride in steel water is closely related to the stability of thin slab continuous casting. The stability of thin slab continuous casting can be improved by increasing the content of chloride. The content of NaCl in thin slab billet steel water is generally 0.10%-0.50%.
2. Requirements for Aluminum Content:
Aluminum is an important factor affecting the quality of thin slab billet continuous casting. Aluminum has a great influence on the metallographic structure of thin slab billet continuous casting. Generally speaking, when the aluminum content of steel water is between 0.009%-0.020%, the thin slab billet has the best casting structure.
3. Requirements for Temperature:
The fluctuations of molten steel temperature directly affects the quality of thin slab billet continuous casting. If the temperature is too high, it will cause porosity, shrinkage and loose structure; if the temperature is too low, it will cause segregation and low strength of thin slab billet. The control of molten steel temperature is important to ensure the quality of thin slab billet continuous casting. In thin strip and medium strip steel continuous casting, the temperature of molten steel is generally controlled between 1450~1520°C.
In summary, the quality requirements of steel water for thin slab billet continuous casting are very strict, not only to require the purity of steel water, but also to require all chemical components to meet the requirements. Only in this way can we ensure the quality of thin slab billet continuous casting, and lay a solid foundation for the seamless production of thin slab continuous casting.
