CN-121988732-A - Liquid sealing device and sealing method for continuous casting

Abstract

The invention discloses a liquid sealing device and a sealing method for continuous casting, and relates to the technical field of steelmaking. The invention aims to solve the technical problems of poor sealing performance, secondary oxidization of molten steel and difficult cleaning of the conventional ceramic fiber sealing gasket. The invention provides a liquid sealing device, which comprises a supporting part made of refractory materials and a meltable part made of a sealing composition, wherein the sealing composition is solid at normal temperature but is heated and melted at the casting temperature of molten steel to form a liquid sealing layer. The sealing method of the invention comprises the steps of arranging the device in a gap of a water gap, and melting a meltable part by utilizing the heat of molten steel to form a liquid sealing layer. The invention realizes absolute and dynamic sealing of the water gap junction by forming the liquid sealing layer in situ, thoroughly eliminates air suction, remarkably improves molten steel quality, and greatly simplifies cleaning work by spontaneous pulverization of the optimized sealing composition after cooling.

Inventors

• LU QIANG
• LI HAO
• ZHOU KANG
• ZHANG CHENG
• SHEN CHANG
• WU JIAN
• WANG GUOCAI
• CHANG ZHENGSHENG
• GUO JUNBO
• NIU KAIJUN

Assignees

• 马鞍山钢铁有限公司

Dates

Publication Date

20260508

Application Date

20260129

Claims (10)

1. 1. A liquid sealing device for continuous casting for sealing a gap formed between a ladle nozzle and a long nozzle in a continuous casting process, the device comprising: a supporting part made of refractory material which remains solid at the casting temperature of molten steel, and And a meltable portion provided in combination with the support portion and composed of a sealing composition which is solid at ordinary temperature but is melted by heating at the casting temperature of the molten steel to form a liquid sealing layer.
2. 2. The liquid sealing apparatus for continuous casting according to claim 1, wherein the meltable portion is provided on a side of the support portion that is close to the ladle nozzle in use.
3. 3. The liquid sealing apparatus for continuous casting according to claim 1 or 2, wherein the apparatus is an annular structure adapted to a gap formed between the ladle nozzle and the long nozzle, wherein the annular structure is a bottomless cup-type or cap-type structure.
4. 4. The liquid sealing device for continuous casting according to claim 1, wherein the material of the support portion is high-temperature ceramic fiber, wherein the high-temperature ceramic fiber includes high-alumina amorphous fiber and/or polycrystalline mullite fiber.
5. 5. The liquid sealing apparatus for continuous casting according to claim 1, wherein the sealing composition is a slag-based material which undergoes a phase change upon cooling to expand in volume, thereby spontaneously pulverizing the solidified liquid sealing layer.
6. 6. The liquid sealing device for continuous casting according to claim 5, wherein the sealing composition comprises, by mass, 43-47% of CaO, 23-27% of SiO 2 ：20-24%;Al 2 O 3 , and 4-12% of Na 2 CO 3 .
7. 7. The liquid sealing apparatus for continuous casting according to claim 6, wherein the sealing composition further comprises an adhesive, wherein the adhesive is a resin-based adhesive or a starch-based adhesive.
8. 8. The liquid sealing apparatus for continuous casting according to claim 1, wherein the meltable portion occupies 1/4 to 1/3 of the total height in the height direction of the apparatus.
9. 9. A sealing method for a continuous casting process, comprising the steps of: S1, before a continuous casting ladle nozzle is butted with a long nozzle, arranging the liquid sealing device according to any one of claims 1-8 in a gap formed between the ladle nozzle and the long nozzle; And S2, casting high-temperature molten steel through the ladle nozzle and the long nozzle, and melting a meltable part of the device by utilizing heat transferred by the high-temperature molten steel to form a liquid sealing layer so as to seal the gap.
10. 10. The method according to claim 9, wherein in the step S2, the liquid sealing layer is sucked into and fills the gap by a negative pressure generated by the flow of molten steel, and the method further comprises the step S3 of cooling a substance formed by solidification of the liquid sealing layer after the casting process is finished, and pulverizing the substance for cleaning.

Description

Liquid sealing device and sealing method for continuous casting Technical Field The invention relates to the technical field of steelmaking, in particular to a sealing device and a sealing method for a water port joint in a continuous casting process. Background In the continuous casting (abbreviated as continuous casting) link of steel smelting, high-temperature molten steel in a ladle is required to be injected into a tundish through a ladle drain nozzle and a long nozzle. In order to prevent secondary oxidation of flowing molten steel in contact with air and leakage of molten steel, the joint of the ladle nozzle and the long nozzle must be effectively sealed. At present, a sealing mode commonly adopted in the industry is to place a sealing gasket made of ceramic fiber cotton between contact surfaces of two water gaps. The sealing gasket is manufactured through pulping and suction filtration molding processes. However, this solution has several drawbacks that are difficult to overcome, firstly, the sealing performance is not stable. The ceramic fiber pad itself is a porous net structure and cannot achieve complete air tightness. In the casting process, negative pressure (Venturi effect) is generated in the molten steel flowing at high speed, and a large amount of air in a gap at the joint is sucked, so that the molten steel is secondarily oxidized and nitrogen is increased, a large amount of oxide inclusions are generated, the castability of the molten steel is deteriorated, the casting blank quality is finally seriously influenced, and the casting blank is extremely unfavorable for the production of high-quality steel (such as sheet billet, bearing steel and the like). Second, durability is insufficient. The prior ceramic fiber pad has lower refractoriness and high-temperature strength, and is easy to ablate under the continuous heat action of high-temperature molten steel (more than about 1500 ℃), so that the sealing performance is further deteriorated and even fails. Third, cleaning and maintenance are difficult. The used sealing gasket is easy to bond with the surface of the bowl part of the long water gap, and needs to consume certain manpower to clean and repair after the steel ladle is replaced, so that the labor intensity is increased, the water gap is easy to damage, and the subsequent sealing effect is affected. Although improvements have been made in the prior art, such as by adjusting the material formulation to increase plasticity or reduce porosity, they do not depart from the category of "solid-solid" contact seals. An inherent disadvantage of this type of sealing is that, once perfect centering of the two gates is not achieved, or there is an uneven contact surface, gaps are inevitably created, and thus a stable and reliable protective casting cannot be achieved. Disclosure of Invention Aiming at the problems of poor sealing performance, easy secondary oxidation of molten steel and difficult cleaning after use of the conventional continuous casting water gap sealing device in the background art, the invention aims to provide the liquid sealing device and the sealing method for continuous casting so as to realize absolute and dynamic sealing of the water gap connection part and simplify cleaning work. In order to solve the technical problems, a first aspect of the present invention provides a liquid sealing device for continuous casting, for sealing a gap formed between a ladle nozzle and a long nozzle in a continuous casting process, the device comprising a supporting portion made of a refractory material that remains solid at a casting temperature of molten steel, and a meltable portion provided in combination with the supporting portion and made of a sealing composition that is solid at ordinary temperature but melts by heating at the casting temperature of molten steel to form a liquid sealing layer. By adopting the technical scheme, the traditional solid sealing mode is overturned by arranging the two-part structure of the meltable part and the supporting part. In the continuous casting process, the meltable part is melted into a liquid sealing layer in situ by utilizing the heat of molten steel, the liquid sealing layer has fluidity, can perfectly fill all irregular gaps between water gaps, forms a dead angle-free liquid-tight barrier, fundamentally solves the problem that the solid sealing cannot avoid the leakage of the gaps, and simultaneously ensures that the liquid sealing layer cannot flow into a steel flow, and ensures the sealing stability and the purity of the molten steel. As a preferable mode of the present invention, the meltable portion is provided on a side of the support portion that is close to or faces the ladle nozzle in use. By arranging the meltable portion closer to the heat source (i.e. the molten steel flowing from the ladle nozzle) it is ensured that it absorbs heat preferentially and rapidly and melts completely, thereby rapidly forming an effective liquid sea