Continuous casting billet evaluation index

Continuous casting billet evaluation index
Evaluation index
To evaluate the quality of continuous casting and rolling billets, there are four main indicators, namely, the geometry of the cast billet, surface quality, internal structure density and steel cleanliness. The quality of these four indicators is closely related to the design of the continuous casting machine, the process adopted, and the characteristics of the solidification of the cast slab. During the casting and solidification process, the continuous casting billet is subjected to the effects of thermal and mechanical stresses such as cooling, bending, straightening, drawing, clamping, and hydrostatic head of the steel, making it prone to various cracks and defects. The characteristics of solidification make it easy to produce internal defects such as central segregation and porosity. In addition, the conditions for the floating and separation of inclusions in the molten steel in the mold are always not as sufficient as die casting, especially the factors that cause molten steel pollution during the entire casting process. It is much more complicated than during die casting. Therefore, non-metallic inclusions, especially large inclusions, have become one of the important defects that endanger the quality of continuous casting slabs. However, the outstanding feature of continuous steel casting|ironmaking is that the process can be controlled, and the causes of almost all quality defects have been clarified so far. Therefore, effective measures can be directly taken to prevent or reduce these quality defects.

Measures to prevent defects of continuous casting slab

At present, the main measures and new technologies taken to prevent the defects of continuous casting slabs are:
1. The main purpose of adopting the detection technology of slag under the big ladle is to prevent the slag from entering the tundish and improve the cleanliness of the molten steel in the tundish.
2. The electromagnetic brake technology of the mold is adopted to reduce the impact of the casting flow and improve the quality.
3. Automatic control of crystallizer liquid level.
4. Compression casting technology.
5. Electromagnetic stirring.
6. Develop surface defect detection technology for cast slabs.
7. Billet quality management.