First-tank flocculated-flow-preventing method used for aluminum-killed steel produced by using thin and medium slab continuous casting machine

Abstract

The invention provides a first-tank flocculated-flow-preventing method used for aluminum-killed steel produced by using a thin and medium slab continuous casting machine. According to the invention, a first-tank desulphurization rate of an LF furnace is higher than 80%; weak argon stirring is adopted during a wire feeding process, a stirring time is controlled at 5-10min, and a calcium weight percentage in molten steel is no smaller than 0.0020%; a tundish baking temperature is no lower than 1100 DEG C; a submerged entry nozzle baking temperature is no lower than 1100 DEG C; a time interval since the tundish baking device is raised until casting is started is shorter than 5min; argon blowing operation is carried out before an upper nozzle is installed; before the tundish is cast, argon is delivered in, and reductive atmosphere in the tundish is maintained. With the method, inclusions can be well absorbed by top slag, and can sufficiently float, such that the generation of flocculated flow can be controlled. With the method, a first-tank flocculated flow occurrence rate when aluminum-killed steel produced by using the thin and medium slab continuous casting machine is treated by using the LF furnace is reduced from 50% to 2%; a casting interruption accident caused by flocculated flow is avoided; and the stability of a steelmaking production process is ensured.

Description

technical field [0001] The invention belongs to the field of continuous casting and refining technology, and in particular relates to a method for producing aluminum-killed steel by a medium-thin slab continuous casting machine used in ladle refining furnace (ie LF furnace) to prevent flocculation in the first tank. Background technique [0002] LF furnace is a refining equipment developed in Japan in the early 1970s. Because of its simple equipment, low investment cost, flexible operation and good refining effect, it has become a rising star in the metallurgical industry, and has been widely used and developed in the world. The refining of LF furnace mainly depends on the white slag in the ladle, blowing argon into the ladle in a low-oxygen atmosphere for stirring, and refining by heating the molten steel passing through the primary furnace with graphite electrodes. Since the argon stirring accelerates the chemical reaction between slag and steel, using arc heating for tem...

AI Technical Summary

Problems solved by technology

In the casting process, it is easy to block the nozzle and cause flocculation

In particular, flocculation is more likely to occur in the production of aluminum-killed steel first cans. The reasons are: first, the tundish is baked with gas, and the oxidizing property in the tundish is relatively strong, which will oxidize Als in molten steel to form Al 2 o 3 Inclusions, attached to the nozzle wall

Secondly, because the temperature of the tundish when pouring is much lower than the temperature of the molten steel, the temperature of the molten steel entering the tundish decreases and the fluidity becomes poor

Because of the above two reasons, the aluminum killed steel head tank produced by the medium and thin slab continuous casting machine is more prone to flocculation, and if the flocculation is serious, it may even lead to a pouring failure accident.