What are the key technologies to realize low superheat casting and the matching technologies
The key to realize low superheat casting is: (1) to control the inclusions in steel and prevent the nozzle from nodulation during low superheat casting; (2) Accurately control the temperature of molten steel in tundish during continuous casting; (3) Stable control of production rhythm of steelmaking continuous casting.
In order to control the composition of inclusions in steel, calcium treatment technology is widely used. However, when the sulfur content in steel is high, CAS inclusions are easy to form, leading to nozzle nodulation, and the dot shaped inclusions formed by calcium treatment are very harmful to some steels. The adoption of low aluminum clean steel technology can achieve the dual goals of improving cleanliness and optimizing inclusions. At present, the temperature of molten steel can be controlled in a very narrow range through secondary refining. In addition, the adoption of tundish insulation technology and inclusion control technology in steel creates conditions for low superheat casting. The research shows that the most effective way to control the temperature stability of molten steel in tundish is to use plasma heating device to supplement stable and reliable neutral heat energy to tundish. In addition, in order to reduce the superheat of molten steel, it is also possible to consider using water-cooled nozzle or conical lossless condenser on the meniscus of molten steel for auxiliary cooling.