The Non-Metallic Inclusions in the Continuous Casting Billets
Continuous casting billets are the products of continuous casting process, which is an important application method in steelmaking. The cast slabs produced by continuous casting equipment have uniform size, shape and composition and less inclusions, as well as superior quality. However, due to the complexity of the casting process and the difficulty in controlling the molten steel, the inclusions in the continuous casting billets cannot be completely eliminated, and thus the non-metallic inclusions have become an important factor affecting the quality of the continuous casting billets.
Non-metallic inclusions in the continuous casting billets are mainly formed by a series of chemical, physical and mechanical factors in the casting and solidifying processes, including stirring, oxidation and mass transfer of slag, gravity, diffusion of oxygen and nitrogen in steel, and oxidation of steel during cooling. These non-metallic inclusions are usually rich in oxygen, nitrogen and carbon, such as alumina oxides, silicates and carbides. They all have different shapes, sizes and distributions.
The impacts of non-metallic inclusions on the performance and properties of continuous casting billets can be divided into two aspects. On the one hand, their presence can cause a decrease in mechanical properties and productivity of the billets, such as a decrease in tensile strength, yield strength, fatigue strength, impact toughness and cold formability. On the other hand, they can lead to the formation of cracks and surface defects in the finished products, and may even cause serious scrap.
Therefore, it is of great importance to ensure the qualities of the continuous casting billets by controlling the non-metallic inclusions contained in them. Today, with the development of advanced chemical and physical methods and powerful analytical instruments, it is possible to accurately control the non-metallic inclusions contained in the continuous casting billets. These advanced methods usually involve controlling the oxygen content in the steel and adding various deoxidizers and protective elements to reduce the impact of non-metallic inclusions on the performance of the continuous casting billets.
In a word, the non-metallic inclusions contained in the continuous casting billets are of great influence on the properties of the products, so it is necessary to control the inclusions in them. To this end, chemical and physical methods and powerful analytical instruments should be used to meet the control requirements. In this way, the quality of continuous casting billets can be ensured, and the performance and properties of the final products can be improved.
