Method for producing ultra-low carbon steel by use of VD (vacuum degasser) device

Abstract

The invention discloses a method for producing ultra-low carbon steel by use of a VD (vacuum degasser) device and belongs to the technical field of refining of molten steel. In the molten steel refining treatment process of the VD device, carbon dioxide is taken as bottom blowing gas for bottom blowing of a steel ladle of the VD device, CO2 and C elements in the molten steel react in the high-vacuum state for forced decarbonization, forced decarbonization and natural forced decarbonization of the molten steel are combined, the decarbonization rate of the VD device is increased, and the metallurgical effect is realized. A steel ladle bottom blowing system is configured with two kinds of gas, namely, carbon dioxide and argon, carbon dioxide and argon can be switched for use, carbon dioxide is used in the vacuum state in the treatment cycle, and argon is adopted in the non-vacuum state in the treatment cycle. The method has the benefits as follows: forced decarbonization and natural forced decarbonization of the molten steel are combined, and ultra-low carbon steel production by the VD device is realized, removal of impurities in steel can be promoted, the desulfurization rate can beincreased, and production of high-purity steel by the VD device is realized; the temperature of the molten steel in the CO2 bottom blowing area is reduced, a bottom blowing brick is protected, and corrosion to the bottom blowing brick is reduced.

Description

technical field [0001] The invention belongs to the technical field of molten steel refining, in particular to a method for producing ultra-low carbon steel with a VD device. Background technique [0002] VD (Vacuum Degasser) device is a widely used vacuum refining equipment for molten steel. It has good functions such as dehydrogenation, deoxidation, decarburization, denitrification and desulfurization, and plays an important role in the production of high-quality steel. Domestic VD devices are mostly used for dehydrogenation and denitrification of molten steel. Some foreign steel mills have reported using VD devices to produce very low carbon or ultra-low carbon steel, and achieved good treatment results. [0003] According to the vacuum decarburization theory, it is generally believed that there are three decarburization mechanisms in the VD decarburization process: surface decarburization of argon bubbles, decarburization of CO bubbles inside molten steel, and decarburiz...

AI Technical Summary

Problems solved by technology

The decarburization of the VD device in the prior art is natural decarburization under a high vacuum state. How to strengthen and improve the decarburization conditions to achieve the purpose of VD deep decarburization is a technical problem faced by the VD device in the production of ultra-low carbon steel. At present, this domestic project Process technology is still under development