A continuous casting tundish dispersion-type breathable ring upper nozzle seat brick and its refining method by argon blowing

Abstract

The invention relates to a continuous casting tundish diffuse-type gas-permeable ring upper nozzle brick cup and an argon blowing refining method thereof. The upper nozzle brick cup comprises an upper nozzle brick cup body, diffuse-type gas-permeable rings, a gas chamber and a gas inlet pipe, wherein the gas-permeable rings are uniformly arranged in a circle; the gas-permeable rings and the circular gas chamber are arranged in the upper nozzle brick cup body; the air chamber is arranged at the bottoms of the diffuse-type gas-permeable rings and communicate with the diffuse-type gas-permeable rings; the upper parts of the gas-permeable rings extend out of the upper surface of the upper nozzle brick cup body by 5 to 10 mm; the gas inlet pipe is connected to one side part of the gas chamber; one end of the gas inlet pipe communicates with the air chamber; the other end of the gas inlet pipe extends out of one side part of the upper nozzle brick cup body, is connected with a metal pipe fitting and communicates with an external argon gas source; an upward circular air curtain barrier is formed after argon gas is blown into the gas inlet pipe, so that gas washing of molten steel entering an upper nozzle is realized, and floating and removing of inclusions are promoted; and a certain quantity of argon bubbles enter the upper nozzle along with a steel flow, so that a stable and continuous circular gas flow is formed, which not only solves the problem of nozzle clogging, but also solves the technical problem that protective argon bubbles enter steel to cause sub-surface bubbles of a casting blank.

Description

technical field [0001] The invention relates to a continuous casting tundish dispersion-type air-permeable ring upper nozzle seat brick and an argon blowing refining method thereof, belonging to the technical field of iron and steel metallurgy continuous casting tundish metallurgy. Background technique [0002] At present, low-carbon aluminum-killed steel and IF steel are produced by casting slab continuous casting machines. In order to solve the problem of nozzle nodulation, various steel mills generally adopt the method of blowing argon gas into the inner wall of the upper nozzle of the tundish. When the flow rate of argon gas entering the nozzle When the value is increased to a certain value, the gas will form an "annular airflow" in the nozzle, which can significantly reduce the problem of nodulation in the nozzle. However, the disadvantages of this technology are: (1) Due to the continuous adhesion of oxides and other inclusions in the molten steel to the inner surface ...

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Problems solved by technology

However, the disadvantages of this technology are: (1) Due to the continuous adhesion of oxides and other inclusions in the molten steel to the inner surface of the upper nozzle, coupled with the static pressure of the molten steel, as the amount of steel passing through the upper nozzle increases, the blown argon gas It is difficult to continue to pass through the inner wall surface of the upper nozzle, and the amount of argon gas entering the nozzle gradually decreases, forming an unstable "circular air flow" in the submerged nozzle, and the molten steel entering the mold is intermittently entrained with "big bubbles" into the mold , a small part of the argon bubbles move to the lower circulation area of ​​the crystallizer, and are captured by the inner surface of the solidified slab shell, and finally form the subcutaneous bubbles of the cast slab; (2) Argon bubbles blown through the inner wall of the upper nozzle enter the nozzle with the steel flow , argon bubbles have little effect on capturing and removing non-metallic inclusions in molten steel

The disadvantage of this patented technology is that it is applied to cast slab continuous casting machine to produce low-carbon aluminum-killed steel and IF steel. It cannot form a stable "circular air flow" in the immersion nozzle, and argon gas must be blown into the inner wall of the upper nozzle to suppress the nozzle. The problem of nodules cannot solve the technical problem that the protective argon bubbles enter the crystallizer and cause subcutaneous bubbles in the slab

The disadvantage of this patented technology is that it is applied to cast slab continuous casting machine to produce low-carbon aluminum-killed steel and IF steel. It cannot form a stable "circular air flow" in the immersion nozzle, and argon gas must be blown into the inner wall of the upper nozzle to suppress the nozzle. The problem of nodules cannot solve the technical problem that the protective argon bubbles enter the crystallizer and cause subcutaneous bubbles in the slab

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