Novel gas curtain element for tundish

Abstract

This invention discloses a novel gas curtain element for tundishes. The beneficial effects are as follows: The permeable core of this invention adopts a corundum spinel-chromium oxide high-temperature sintering system, forming a uniformly dispersed and stably interconnected microporous structure. Argon gas is evenly distributed through the central gas guide hole and then dispersed and discharged from the micropores on the working surface, forming a continuous and stable argon gas curtain barrier laterally within the tundish. This gas curtain can adsorb and carry fine inclusions and harmful gases in the molten steel to the slag layer quickly, improving the inclusion removal rate. Simultaneously, this gas curtain element is a permeable purification structure laid horizontally at the bottom, completely replacing traditional refractory components such as slag weirs and retaining walls in tundishes. This fundamentally avoids secondary pollution of molten steel caused by slag weir peeling, erosion, and slag shedding. Furthermore, the sealing layer uses a dense refractory material, preventing material shedding and component leaching, and ensuring no external inclusions are introduced into the molten steel throughout the process, significantly improving the internal quality and mechanical property stability of the cast billet.

Description

Technical Field

[0001] This invention relates to the field of tundish air curtain elements, and more particularly to a novel air curtain element for tundishes. Background Technology

[0002] As the final container for receiving and purifying molten steel from the ladle to the continuous casting machine in the steelmaking continuous casting process, the tundish is a core piece of equipment for ensuring continuous casting operations, improving the cleanliness of molten steel, and stabilizing the quality of cast billets. With the increasing demands for internal purity, mechanical properties, and fatigue resistance of steel from high-end equipment manufacturing, shipbuilding, nuclear power, high-speed rail, and heavy plate industries, clean steelmaking has become a core development direction for the modern steel industry. The secondary purification effect of the molten steel in the tundish directly determines the quality grade of the final steel product.

[0003] Current traditional tundish purification processes generally employ refractory structures such as slag weirs, baffles, and flow stabilizers to achieve initial purification by altering the flow direction of molten steel, extending its residence time, and promoting the flotation of large inclusions. However, in actual production, this traditional method has significant technical drawbacks: 1. Insufficient removal capacity for minute inclusions: Relying solely on flow field adjustment is insufficient to effectively capture and remove fine non-metallic inclusions smaller than 10μm, failing to meet the requirements for producing high-end clean steel and ultra-pure steel; 2. Prone to secondary contamination of molten steel: Slag weirs and baffles are prone to spalling, erosion, and slag shedding under the scouring and thermal shock of high-temperature molten steel, allowing refractory material particles to directly enter the molten steel and form new inclusions; 3. Low gas-liquid contact efficiency: Lacking active air flotation purification function, dissolved gases and fine inclusions in the molten steel are difficult to quickly float and be removed; 4. High refractory material consumption and complex processes: Slag weirs require frequent replacement and construction, increasing production costs and maintenance time, which is detrimental to energy conservation, emission reduction, and efficient continuous casting.

[0004] To improve purification efficiency, existing technologies attempt to install permeable elements at the bottom of the tundish or inside the retaining wall, using argon gas to form an air curtain to assist purification. However, existing permeable elements generally suffer from uneven ventilation, discontinuous air curtains, easy clogging at high temperatures, poor structural adaptability, and unreliable sealing. Some products use an integral permeable structure, causing argon gas to escape from multiple directions, making it impossible to form a directional, uniform, and stable transverse air curtain. Some products have insufficient resistance to high-temperature corrosion and thermal shock, resulting in a short service life. Some products have complex connection structures, making on-site installation and maintenance inconvenient and difficult to reliably replace traditional slag-blocking weir plates. Summary of the Invention

[0005] The purpose of this invention is to provide a novel air curtain element for intermediate packaging in order to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions: A novel air curtain element for tundishes includes a permeable core. The permeable core is covered with a refractory sealing layer on five sides, and the upper side of the permeable core not covered by the sealing layer is the working surface. The permeable core is made of corundum spinel system with added chromium oxide and fired at high temperature. It has an internal argon gas inlet for introducing argon gas, and the inlet of the argon gas inlet is connected to a stainless steel argon gas pipe. In use, the permeable core is laid horizontally at the bottom of the tundish. Argon gas enters the permeable core through the argon gas pipe and the argon gas inlet and exits through the tiny holes in the working surface, forming a horizontal air curtain wall inside the tundish.

[0007] Furthermore, the breathable core turns purple after high-temperature firing, and the entire working surface is a purple area.

[0008] By adopting the above technical solution, the purple matrix and purple working surface formed after the sintering of the permeable core are unique characteristics of high-temperature sintering. They are a direct reflection of the full solid-phase reaction and dense grain growth of corundum spinel and chromium oxide components. They can serve as an appearance criterion for judging the sintering qualification and material performance of the product, making it convenient for production quality inspectors to quickly identify the product molding quality and effectively prevent defective products such as under-burned, over-burned, and unevenly composed products from being put into use on site. At the same time, the purple working surface area corresponds to the effective permeable working area of ​​the component. This area has the optimal microporous structure, the best connectivity, and the most stable permeability, with extremely high identification. It can help on-site operation and maintenance personnel to quickly locate the air outlet working surface, accurately identify the effective purification area, facilitate equipment installation calibration, daily inspection and loss detection, effectively avoid problems such as installation misalignment and working surface obstruction, and ensure the stable performance of the air curtain purification effect.

[0009] Furthermore, the sealing layer is a dense refractory material used to prevent argon gas from escaping from the non-working surface of the permeable core, thereby enabling argon gas to be discharged directionally from the working surface.

[0010] By adopting the above technical solution, the dense refractory sealing layer possesses the characteristics of zero air permeability, high density, high temperature resistance, and corrosion resistance. It can completely seal the tiny pores on the bottom surface and four side surfaces of the ventilated core, completely eliminating the problem of argon gas leakage and dissipation from non-working surfaces, and avoiding argon gas diversion, leakage, and waste. At the same time, it enables 100% directional dispersion and discharge of argon gas from the top working surface, maximizing the concentrated gas flow energy and ensuring that the formed gas curtain is continuous, complete, uniform in thickness, and stable in strength, without defects such as gas curtain discontinuity or uneven density caused by side leakage. In addition, the sealing layer can isolate molten steel and slag from direct contact with the non-working surfaces of the ventilated core, blocking structural damage caused by slag penetration and erosion and high-temperature gas overflow, providing all-round protection for the ventilated core substrate structure, significantly improving the overall resistance of the component to high-temperature erosion and slag corrosion, and extending the continuous service life of the equipment.

[0011] Furthermore, the air guide hole is arranged along the length direction of the air permeable core and penetrates the air permeable core, for uniformly distributing argon gas into the interior of the air permeable core.

[0012] By adopting the above technical solution, the elongated gas guide hole can achieve argon gas delivery along the entire length of the permeable core without dead angles, effectively solving the problems of uneven gas supply, weak gas output at both ends, and concentrated gas output in the middle of the traditional point-shaped and segmented gas guide structure. After entering the gas guide hole, the argon gas can diffuse rapidly and be steadily distributed along the entire length, so that the gas pressure inside the permeable core remains uniform. This ensures that the gas output volume and gas output rate of the micropores in various areas of the working face are highly uniform, ultimately forming a horizontally fully covered, blind-spot-free, and uniformly dense overall gas curtain barrier. At the same time, the gas guide hole has smooth flow channels and low resistance, making it less prone to problems such as dust accumulation, blockage, and uneven gas pressure, ensuring the stability of long-term continuous gas supply and adapting to the long-term uninterrupted production needs of continuous casting process.

[0013] Furthermore, the argon gas connector is sealed to the gas inlet for quick connection with an external argon gas supply pipeline.

[0014] By adopting the above technical solution, the stainless steel argon gas connector possesses advantages such as high temperature resistance, oxidation resistance, non-deformation, and strong sealing performance. Its precisely matched sealing connection structure with the gas inlet completely eliminates problems such as leakage, pressure loss, and uneven gas intake at the interface, ensuring that external argon gas can be introduced into the vent core without loss, under stable pressure, and at a uniform speed. Simultaneously, the standardized connector structure allows for quick insertion and connection to conventional on-site gas supply pipelines, eliminating the need for complex welding or modification procedures. This significantly simplifies equipment installation, replacement, and maintenance processes, reducing on-site construction difficulty and labor costs. Furthermore, the interface connection is robust, vibration-resistant, and resistant to high-temperature aging. It maintains absolute sealing even under conditions of high tundish temperature and slight equipment vibration, preventing production problems such as gas curtain failure and substandard molten steel purification due to interface leakage, thus improving equipment operational stability and maintenance efficiency.

[0015] Furthermore, the interior of the permeable core is diffusely distributed with tiny ventilation holes that connect the air guide holes and the working surface, in order to form a uniform and stable argon gas curtain.

[0016] By adopting the above technical solution, after the sintering of the permeable core, a large number of diffusely distributed, interconnected, and uniformly sized micro-ventilation channels are formed inside. The channels are precisely connected from top to bottom to the central air guide hole and the top working surface, constructing a complete, regular, and unobstructed three-dimensional air guiding network. After the argon gas is stabilized by the air guide hole, it can overflow from the working surface in a diffuse, low-flow, and uniform state through a large number of micro-holes, avoiding the problems of concentrated air holes, rapid gas flow, and uneven airflow in traditional permeable structures. This microporous air guiding structure can form a continuous, soft, and fully covered transverse air curtain at the bottom of the molten steel. It can ensure that the argon gas and the molten steel are in full contact, efficiently adsorb and capture micron-sized fine inclusions and harmful gases, and prevent the molten steel from violently churning due to excessive airflow in a single hole. Structurally, it ensures the high efficiency of air curtain purification and the stability of the molten steel surface.

[0017] Furthermore, the air curtain element is laid directly on the bottom of the tundish as an integral structure, independently forming the steel purification and flow field control structure within the tundish, replacing the traditional slag-blocking weir plate.

[0018] By adopting the above technical solution, this air curtain element adopts an integrated, integral molding structure, eliminating the need for splicing and assembly. It can be directly laid flat and installed at the bottom of the tundish, eliminating the need for building and fixing traditional slag weirs, retaining walls, and diversion components. This completely replaces the traditional tundish flow field control and slag-blocking refractory structure. On the one hand, it eliminates the cumbersome procedures of traditional refractory component construction, maintenance, repair, and replacement, significantly reducing the consumption of refractory materials, reducing solid waste generation and production energy consumption, and simplifying the tundish construction process. On the other hand, it fundamentally solves the problems of cracking, peeling, and slag shedding caused by long-term slag weir plates being washed by molten steel, high-temperature erosion, and rapid heating and cooling. It completely eliminates secondary inclusion pollution caused by refractory debris falling into the molten steel, improving the purity of molten steel and the stability of billet quality from a hardware perspective. At the same time, the integral structure laid at the bottom can optimize the molten steel flow field in the tundish, extend the residence time of molten steel, and further improve the removal effect of inclusions in conjunction with the purification effect of the air curtain.

[0019] Furthermore, the argon flow rate can be adjusted to keep the gas curtain strength and the degree of molten steel turbulence within a controllable range, avoiding agitation of the protective slag on the surface of the molten steel and preventing secondary oxidation and inclusion of impurities.

[0020] By adopting the above technical solution, the equipment can precisely adjust the argon input flow rate and pressure through an external gas supply system, achieving refined control and adjustment of the gas curtain output intensity, airflow density, and molten steel agitation intensity. It can match the optimal gas supply parameters according to different steel grades, casting speeds, and molten steel purity requirements. Under low flow conditions, it can maintain a stable, weak gas curtain to meet the purification needs of conventional steel grades. In the production of high-purity steel grades, the flow rate can be appropriately increased to enhance the flotation effect of inclusions. Throughout the process, the molten steel's agitation state can be controlled within a reasonable range, ensuring moderate agitation to break up static stratification and promote the rapid aggregation and flotation of fine inclusions. It also avoids excessive airflow that could cause violent fluctuations and tumbling of the molten steel surface, effectively preventing the crystallizer protective slag from being drawn into the molten steel. Simultaneously, it isolates air from contact with the molten steel, preventing the intrusion of harmful gases such as oxygen and nitrogen, perfectly avoiding secondary oxidation defects in the molten steel, and adapting to the production process requirements of various high-quality steel products.

[0021] Furthermore, the corundum spinel-chromium oxide system of the breathable core gives it high-temperature corrosion resistance, thermal shock resistance, and high throughput.

[0022] By adopting the above technical solutions, the corundum spinel matrix possesses excellent high-temperature rigidity, high refractoriness, and structural stability, capable of withstanding long-term high-temperature conditions above 1500℃ in the tundish, and the matrix is ​​not prone to softening, deformation, or collapse. The addition of chromium oxide significantly optimizes the material's grain structure, refining grains and densifying grain boundaries, greatly enhancing the material's resistance to molten steel penetration, slag erosion, and high-temperature scouring, effectively resisting long-term scouring by molten steel and slag wetting corrosion. Simultaneously, the composite system has a uniform coefficient of thermal expansion, perfectly adapting to the frequent start-ups and shutdowns and rapid temperature rises and falls in continuous casting production, greatly improving thermal shock resistance and preventing material cracking, spalling, and micropore closure. Furthermore, after sintering, the micropore structure exhibits extremely strong connectivity and a high open rate, preventing slag accumulation and pore blockage during long-term high-temperature use, maintaining stable air permeability and ventilation throughout the process, ensuring long-term continuous and stable equipment operation, and significantly reducing the frequency of downtime due to malfunctions.

[0023] Furthermore, the breathable core is a pre-made semi-finished product that is machine-pressed and then fired. The sealing layer is formed by casting the breathable core with sealing material after it is fixed on the mold, and then demolding and baking. The sealing layer fully covers the bottom surface and four side surfaces along the outline of the breathable core, and only forms a continuous exposed air outlet working surface on the upper side.

[0024] By adopting the above technical solution, the interface between the sealing layer and the ventilated core is seamlessly bonded and tightly integrated, with no gaps, no delamination, and no risk of detachment. Compared with later pasting and spraying sealing structures, the sealing performance, integrity, and high temperature resistance are greatly improved, and problems such as bulging, cracking, and detachment of the sealing layer will not occur under high temperature conditions. The five-sided fully enclosed structural design forms an all-round closed protection for the bottom surface and four sides of the ventilated core, leaving only the top complete and continuous working surface as the only air outlet channel, achieving precise constraint on the air outlet direction and area. It not only completely avoids the problems of air leakage, slag seepage, and corrosion on non-working surfaces, but also concentrates airflow to improve the air curtain purification effect, and provides all-round protection for the ventilated core substrate, blocking the erosion and damage of molten steel and slag to the sides and bottom, greatly extending the overall service life of the component and reducing equipment wear and production costs.

[0025] The specific working principle is as follows: This tundish gas curtain element relies on a high-performance permeable matrix of corundum spinel-chromium oxide and a five-sided sealed directional gas guiding structure to achieve integrated functions of efficient purification of molten steel in the tundish, flow field optimization and quality control. The overall workflow is coherent and controllable. During the equipment installation stage, the integrated gas curtain element is directly laid horizontally and fixed to the bottom of the continuous casting tundish, replacing the traditional slag weir and retaining wall structure, completing rapid installation and sealing connection. The stainless steel argon gas pipe is sealed to the external adjustable argon gas supply pipeline to ensure that the gas intake channel is unobstructed and leak-free. During the production operation phase, the external gas supply system precisely controls the argon flow and pressure according to the steel grade and casting parameters. Argon is smoothly introduced into the internal venting holes of the venting core through stainless steel argon pipes. Relying on the pressure stabilization and flow distribution effect of the venting holes, the argon is evenly distributed throughout the entire venting core. Subsequently, the argon overflows uniformly, diffusely, and vertically from the top exposed working surface through numerous dispersed and stably connected micro-vents within the venting core, forming a continuous, uniformly thick, and highly stable argon protective gas curtain barrier at the bottom of the tundish. As the gas curtain rises, it fully contacts the flowing molten steel, precisely capturing micron-sized oxides, sulfides, and other fine inclusions in the molten steel that are difficult to remove using conventional processes through bubble adsorption, entrainment, and buoyancy. Simultaneously, it adsorbs harmful gases such as dissolved hydrogen and nitrogen in the molten steel, carrying various impurities to the slag layer on the surface of the molten steel for adsorption and removal, thus efficiently purifying the molten steel. Meanwhile, at the bottom... The uniformly rising argon bubbles can create a moderate and gentle stirring effect on the molten steel, optimizing the flow field inside the tundish, extending the residence time of the molten steel, and promoting the full floating and separation of inclusions. Furthermore, the stirring intensity can be precisely controlled by adjusting the argon flow rate, avoiding violent fluctuations in the molten steel surface and preventing the entrapment of protective slag and secondary oxidation of the molten steel. In addition, the five-sided sealing layer of the permeable core can completely block lateral and bottom leakage of argon gas, while isolating the erosion and penetration of the substrate by molten steel and slag. Combined with the high-temperature stability, thermal shock resistance, and erosion resistance of high-performance materials, it ensures that the components maintain unobstructed micropores and stable gas output under harsh conditions of long-term high temperature, strong erosion, and rapid heating and cooling, without refractory debris falling off or foreign inclusions being introduced. This fundamentally solves the pain points of traditional tundish metallurgical processes, such as secondary pollution, incomplete removal of inclusions, and easy equipment wear and tear. Ultimately, it steadily improves the purity of molten steel and the internal quality of the billet, achieving efficient, clean, low-consumption, and long-term production in tundish metallurgical processes.

[0026] The beneficial effects of this invention are as follows: The permeable core in this invention adopts a corundum spinel-chromium oxide high-temperature sintering system, forming a uniformly dispersed and stably interconnected microporous structure. Argon gas is evenly distributed through the central guide hole and then diffuses out from the micropores on the working surface, forming a continuous and stable argon gas curtain barrier laterally within the tundish. This gas curtain can adsorb and carry fine inclusions and harmful gases from the molten steel to the slag layer, significantly improving the inclusion removal rate. It is particularly effective at removing tiny inclusions that are difficult to remove using traditional processes, consistently meeting the purity requirements of high-end clean steel and thick slabs. Furthermore, this gas curtain element is a permeable purification structure laid horizontally at the bottom, ensuring complete purification. It completely replaces traditional refractory components such as slag weirs and retaining walls in tundishes, fundamentally preventing secondary pollution of molten steel caused by slag weir peeling, erosion, and slag shedding. Simultaneously, the sealing layer uses dense refractory material, preventing material shedding and component leaching, and ensuring no foreign inclusions are introduced into the molten steel throughout the process, significantly improving the internal quality and mechanical property stability of the cast billet. Furthermore, by adjusting the external argon gas flow rate, the gas curtain's output intensity and the molten steel's turbulence state can be precisely controlled, achieving appropriate stirring of the molten steel and efficient flotation of inclusions, while avoiding violent fluctuations in the molten steel surface, slag entrapment, and secondary oxidation of the molten steel. The permeable core has a stable high-temperature structure, high opening rate, and is not easily clogged, making it suitable for continuous high-temperature and strong scouring conditions. It maintains stable ventilation even under rapid heating and cooling conditions, ensuring reliable long-term continuous production. Furthermore, the permeable core uses corundum spinel as its matrix, with added chromium oxide and high-temperature sintering. Its high-temperature strength, resistance to molten steel erosion, slag penetration resistance, and thermal shock resistance are significantly superior to conventional permeable refractory materials. Combined with a five-sided sealing layer for directional airflow constraint, it ensures uniform airflow while effectively protecting the permeable core, reducing direct erosion from molten steel and slag, significantly extending its overall service life, and reducing replacement frequency and production costs. Moreover, this air curtain element adopts an integrated structure with five-sided sealing and one-sided airflow, allowing for direct horizontal installation at the bottom of the tundish, simplifying positioning, enabling rapid installation, and ensuring a tight seal. The system is highly reliable; the stainless steel argon gas connector allows for quick connection to external gas supply pipelines, ensuring a tight seal, preventing leaks, and facilitating maintenance. It is adaptable to continuous casting tundishes of varying capacities and structures without requiring modifications to the tundish itself, demonstrating strong versatility and field suitability. Furthermore, the design of this gas curtain element eliminates the need for slag-blocking weirs, reducing refractory material consumption, construction labor, and maintenance time, thereby lowering production energy consumption and solid waste emissions. Simultaneously, it improves the steel qualification rate and billet yield, reducing scrap losses due to inclusion defects. Overall, it promotes the upgrading of tundish metallurgical processes towards high efficiency, energy saving, cleanliness, and intelligence, yielding significant economic and social benefits. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a novel air curtain element for intermediate packaging as described in this invention; Figure 2 This is a front cross-sectional view of a novel air curtain element for intermediate packaging as described in this invention.

[0028] The annotations in the attached figures are explained as follows: 1. Ventilation core; 2. Sealing layer; 3. Argon gas connection pipe; 4. Gas vent. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings: like Figures 1-2 As shown, a novel air curtain element for tundishes includes a permeable core 1. The permeable core 1 is covered with a refractory sealing layer 2 on its five outer sides. The upper side of the permeable core 1 that is not covered by the sealing layer 2 is the working surface. The permeable core 1 is made of corundum spinel system with added chromium oxide and fired at high temperature. It has an internal air guide hole 4 for introducing argon gas. The air inlet of the air guide hole 4 is connected to a stainless steel argon gas pipe 3. In use, the permeable core 1 is laid horizontally at the bottom of the tundish. Argon gas enters the permeable core 1 through the argon gas pipe 3 and the air guide hole 4 and is discharged through the tiny holes in the working surface, forming a horizontal air curtain wall inside the tundish.

[0030] In this embodiment, the permeable core 1 turns purple after high-temperature firing, and the entire working surface is a purple area. The purple matrix and purple working surface formed after firing the permeable core 1 are unique characteristics of high-temperature sintering. They are a direct reflection of the full solid-phase reaction and dense grain growth of corundum spinel and chromium oxide components. This can be used as an appearance judgment basis for product sintering qualification and material performance compliance, making it convenient for production quality inspectors to quickly identify the product molding quality and effectively prevent defective products such as under-fired, over-fired, and unevenly composed products from being put into use on site. At the same time, the purple working surface area corresponds to the effective permeable working area of ​​the component. This area has the optimal microporous structure, the best connectivity, and the most stable permeability uniformity, with extremely high recognizability. It can help on-site operation and maintenance personnel quickly locate the air outlet working surface and accurately identify the effective purification area, which is convenient for equipment installation calibration, daily inspection and loss detection, effectively avoiding problems such as installation misalignment and working surface obstruction, and ensuring the stable performance of the air curtain purification effect.

[0031] In this embodiment, the sealing layer 2 is a dense refractory material used to prevent argon gas from escaping from the non-working surface of the permeable core 1, thus enabling argon gas to be discharged directionally from the working surface. The dense refractory material sealing layer 2 has the characteristics of zero permeability, high density, high temperature resistance, and corrosion resistance. It can completely seal the tiny pores on the bottom surface and four side surfaces of the permeable core 1, completely eliminating the problem of argon gas leakage and dissipation from the non-working surface, and avoiding argon gas diversion, leakage, and waste. At the same time, it enables 100% directional dispersion and discharge of argon gas from the top working surface, maximizing the concentrated air kinetic energy, ensuring that the formed air curtain is continuous, complete, uniform in thickness, and stable in strength, and will not cause defects such as air curtain discontinuity or uneven density due to side leakage. In addition, the sealing layer 2 can isolate the molten steel and slag from direct contact with the non-working surface of the permeable core 1, blocking the structural damage caused by slag penetration and erosion and high-temperature gas flow overflow, and protecting the base structure of the permeable core 1 in all aspects. This significantly improves the overall resistance of the component to high-temperature erosion and slag corrosion, and extends the continuous service life of the equipment.

[0032] In this embodiment, the gas guide hole 4 is arranged along the length of the permeable core 1 and penetrates the permeable core 1. It is used to evenly distribute argon gas into the interior of the permeable core 1. The elongated gas guide hole 4 can realize the delivery of argon gas along the entire length of the permeable core 1 without dead angles, effectively solving the problems of uneven gas supply, weak gas output at both ends, and concentrated gas output in the middle of the traditional point-shaped and segmented gas guide structure. After the argon gas enters the gas guide hole 4, it can diffuse rapidly and stabilize and distribute the flow along the entire length, so that the gas pressure inside the permeable core 1 remains uniform. This ensures that the gas output volume and gas output rate of the micropores in each area of ​​the working surface are highly uniform, and finally forms a horizontal, fully covered, blind-spot-free, and uniformly dense overall gas curtain barrier. At the same time, the flow channel of the gas guide hole 4 is unobstructed and has low resistance, so it is not easy to have problems such as dust accumulation, blockage, and uneven gas pressure, ensuring the stability of long-term continuous gas supply and adapting to the long-term uninterrupted production needs of continuous casting process.

[0033] In this embodiment, the argon gas connector 3 is sealed to the gas inlet 4 for quick connection with the external argon gas supply pipeline. The stainless steel argon gas connector 3 has the advantages of high temperature resistance, oxidation resistance, non-deformation, and strong sealing performance. The precise matching sealing connection structure with the gas inlet 4 can completely eliminate problems such as leakage, pressure loss, and uneven gas intake at the interface, ensuring that external argon gas can be introduced into the gas permeable core 1 without loss, under stable pressure, and at a uniform speed. At the same time, the standardized connector structure can be quickly plugged into and fixed with conventional gas supply pipelines on site without complicated welding or modification procedures, greatly simplifying the equipment installation, replacement, and maintenance process, and reducing on-site construction difficulty and labor costs. Moreover, the interface connection is stable, vibration-resistant, and resistant to high temperature aging. It can still maintain absolute sealing under the conditions of high temperature in the tundish and slight equipment vibration, avoiding production problems such as gas curtain failure and substandard steel purification due to interface leakage, thus improving equipment operation stability and maintenance efficiency.

[0034] In this embodiment, the permeable core 1 has micro-ventilation holes that connect the air guide hole 4 to the working surface, forming a uniform and stable argon gas curtain. After the permeable core 1 is sintered, a large number of micro-ventilation channels with uniform pore size are formed inside, which are dispersed, interconnected and precisely connect the central air guide hole 4 to the top working surface from top to bottom, constructing a complete, regular and unobstructed three-dimensional air guiding network. After the argon gas is stabilized by the air guide hole 4, it can overflow from the working surface in a diffuse, micro-flow and uniform state through a large number of micro-holes, avoiding the problems of concentrated pores, rapid gas flow and uneven air flow in traditional permeable structures. This micro-pore air guiding structure can form a continuous, soft and fully covered transverse air curtain at the bottom of the molten steel, which can ensure that the argon gas and the molten steel are in full contact, efficiently adsorb and capture micron-sized fine inclusions and harmful gases, and prevent the molten steel from violently churning due to excessive air flow in a single hole. Structurally, it ensures the high efficiency of air curtain purification and the stability of the molten steel surface.

[0035] In this embodiment, the air curtain element is laid directly on the bottom of the tundish as a whole structure, independently forming the steel purification and flow field control structure within the tundish, replacing the traditional slag-blocking weir plate. This air curtain element adopts an integrated, integrally molded structure, requiring no splicing or assembly, and can be directly laid flat on the bottom of the tundish. It eliminates the need for constructing and fixing traditional slag-blocking weirs, retaining walls, and diversion components, completely replacing the traditional tundish flow field control and slag-blocking refractory structure. On the one hand, it saves the cumbersome procedures of traditional refractory component construction, maintenance, inspection, and replacement, significantly reducing the need for refractory components. This reduces the consumption of refractory materials, decreases solid waste generation and production energy consumption, and simplifies the tundish construction process. On the other hand, it fundamentally solves the problems of cracking, peeling, and slag shedding caused by long-term erosion by molten steel, high temperature, and rapid heating and cooling of traditional slag-blocking weirs. It completely eliminates secondary inclusion pollution caused by refractory debris falling into the molten steel, improving the purity of molten steel and the stability of billet quality from a hardware perspective. At the same time, the integral structure laid at the bottom can optimize the molten steel flow field in the tundish, extend the residence time of molten steel, and further improve the removal effect of inclusions in conjunction with the air curtain purification effect.

[0036] In this embodiment, the argon flow rate is adjustable, ensuring that the gas curtain strength and the degree of molten steel turbulence are within a controllable range. This avoids disturbing the protective slag on the surface of the molten steel, preventing secondary oxidation and inclusion in the molten steel. The equipment can precisely adjust the argon input flow rate and pressure through an external gas supply system, achieving fine-grained controllability and adjustability of the gas curtain output strength, gas flow density, and molten steel turbulence. The optimal gas supply parameters can be matched according to different steel grades, casting speeds, and molten steel purity requirements. Under low flow conditions, a stable and weak gas curtain can be maintained to meet the purification requirements of conventional steel grades. When producing high-purity steel grades, the flow rate can be appropriately increased to enhance the inclusion flotation effect. Throughout the process, the tumbling state of molten steel can be controlled within a reasonable range. This ensures proper stirring of the molten steel, breaks up static stratification, and promotes the rapid aggregation and floating of fine inclusions. At the same time, it avoids excessive airflow that could cause violent fluctuations and tumbling of the molten steel surface, effectively preventing the protective slag from being drawn into the molten steel. It also isolates the molten steel from air contact, preventing the intrusion of harmful gases such as oxygen and nitrogen, perfectly avoiding the defects of secondary oxidation of molten steel, and adapting to the production process requirements of various types of high-quality steel.

[0037] In this embodiment, the corundum spinel-chromium oxide system of the permeable core 1 provides it with high-temperature erosion resistance, thermal shock resistance, and high open-cell rate. The corundum spinel matrix possesses excellent high-temperature rigidity, high refractoriness, and structural stability, capable of withstanding long-term high-temperature conditions above 1500℃ in the tundish, and the matrix is ​​not prone to softening, deformation, or collapse. The addition of chromium oxide significantly optimizes the material's grain structure, refining the grains and densifying the grain boundaries, greatly improving the material's resistance to molten steel penetration, slag erosion, and high-temperature scouring, effectively resisting long-term scouring by molten steel and slag wetting corrosion. At the same time, the composite system has a uniform coefficient of thermal expansion, perfectly adapting to the frequent start-ups and shutdowns and rapid temperature rises and falls in continuous casting production, greatly improving thermal shock resistance and avoiding material cracking, spalling, and micropore closure and blockage. Furthermore, after sintering, the micropore structure of the material has extremely strong connectivity and a high open-cell rate, making it less prone to slag accumulation and pore blockage during long-term high-temperature use, maintaining stable permeability and air conduction performance throughout the process, ensuring long-term continuous and stable operation of the equipment, and significantly reducing the frequency of downtime due to malfunctions.

[0038] In this embodiment, the ventilated core 1 is a pre-made semi-finished product that is machine-pressed and then fired. The sealing layer 2 is formed by casting the ventilated core 1 with sealant after it is fixed on the mold, and then demolding and baking it. The sealing layer 2 completely covers the bottom surface and four side surfaces along the outline of the ventilated core 1, and only forms a continuous exposed air outlet working surface on the top side. The interface between the sealing layer 2 and the ventilated core 1 is seamlessly attached and tightly bonded, without gaps, delamination, or the risk of falling off. Compared with the later pasting and spraying of the sealing structure, the sealing performance, integrity, and high temperature resistance are greatly improved, and there will be no problems such as bulging, cracking, or falling off of the sealing layer 2 under high temperature conditions. The five-sided fully enclosed structural design forms an all-round sealed protection for the bottom surface and four sides of the ventilated core 1, leaving only the top continuous working surface as the only air outlet channel, achieving precise constraint on the air outlet direction and area; it not only completely avoids the problems of air leakage, slag seepage and corrosion on non-working surfaces, and concentrates airflow to improve the air curtain purification effect, but also provides all-round protection for the ventilated core 1 substrate, blocking the erosion and damage of molten steel and slag to the sides and bottom surface, greatly extending the overall service life of the component, and reducing equipment wear and production costs.

[0039] The specific working principle is as follows: The tundish gas curtain element relies on the high-performance permeable matrix of corundum spinel-chromium oxide, the five-sided sealing and the upper directional gas guiding structure to achieve the integrated functions of efficient purification of molten steel in the tundish, flow field optimization and quality control. The overall workflow is coherent and controllable. During the equipment installation stage, the integrated gas curtain element is directly laid horizontally and fixed to the bottom of the continuous casting tundish, replacing the traditional slag weir and retaining wall structure, completing the rapid installation and sealing connection. The stainless steel argon gas pipe 3 is sealed to the external adjustable argon gas supply pipeline to ensure that the gas inlet channel is unobstructed and leak-free. During the production operation phase, the external gas supply system precisely controls the argon flow and pressure according to the steel grade and casting parameters. Argon is smoothly introduced into the internal venting holes 4 of the permeable core 1 through a stainless steel argon pipe 3. Relying on the pressure stabilization and flow distribution effect of the venting holes 4, the argon is evenly distributed throughout the entire permeable core 1. Subsequently, the argon overflows uniformly, diffusely, and vertically from the top exposed working surface through numerous dispersed and stably connected micro-vents within the permeable core 1, forming a continuous, uniformly thick, and highly stable argon protective gas curtain barrier at the bottom of the tundish. As the gas curtain rises, it fully contacts the flowing molten steel, precisely capturing micron-sized oxides, sulfides, and other fine inclusions in the molten steel that are difficult to remove using conventional processes through bubble adsorption, entrainment, and buoyancy. Simultaneously, it adsorbs harmful gases such as hydrogen and nitrogen dissolved in the molten steel, carrying various impurities to the slag layer on the surface of the molten steel for adsorption and removal, thus efficiently purifying the molten steel. Meanwhile, at the bottom... The uniformly rising argon bubbles can create a moderate and gentle stirring effect on the molten steel, optimizing the flow field of the molten steel inside the tundish, extending the residence time of the molten steel, and promoting the full floating and separation of inclusions. Moreover, the stirring intensity can be precisely controlled by adjusting the argon flow rate, avoiding violent fluctuations in the molten steel surface and preventing the entrapment of protective slag and secondary oxidation of the molten steel. In addition, the five-sided sealing layer 2 on the permeable core 1 can completely block the lateral and bottom leakage of argon gas, while isolating the erosion and penetration of molten steel and slag into the substrate. Combined with the high-temperature stability, thermal shock resistance, and erosion resistance of high-performance materials, it ensures that the components maintain unobstructed micropores and stable gas output under harsh conditions of long-term high temperature, strong erosion, and rapid heating and cooling, without refractory debris falling off or foreign inclusions being introduced. This fundamentally solves the pain points of traditional tundish metallurgical processes such as secondary pollution, incomplete removal of inclusions, and easy equipment wear, ultimately steadily improving the purity of molten steel and the internal quality of the billet, and realizing efficient, clean, low-consumption, and long-term production of tundish metallurgical processes.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A novel air curtain element for intermediate tundishes, characterized in that: The device includes a permeable core (1), which is covered with a refractory sealing layer (2) on its five outer sides. The upper side of the permeable core (1) that is not covered by the sealing layer (2) is the working surface. The permeable core (1) is made of corundum spinel system with added chromium oxide and fired at high temperature. It has an air guide hole (4) for introducing argon gas. The air inlet of the air guide hole (4) is connected to a stainless steel argon gas pipe (3). When in use, the permeable core (1) is laid horizontally at the bottom of the intermediate package. Argon gas enters the permeable core (1) through the argon gas pipe (3) and the air guide hole (4) and is discharged through the tiny holes on the working surface, forming a horizontal air curtain wall in the intermediate package.

2. The novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The breathable core (1) turns purple after being fired at high temperature, and the entire working surface is a purple area.

3. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The sealing layer (2) is a dense refractory material used to prevent argon from overflowing from the non-working surface of the permeable core (1) and to enable argon to be discharged directionally from the working surface.

4. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The air guide hole (4) is arranged along the length direction of the air permeable core (1) and penetrates the air permeable core (1) to uniformly distribute argon gas into the interior of the air permeable core (1).

5. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The argon gas connector (3) is sealed to the gas guide hole (4) for quick connection with the external argon gas supply pipeline.

6. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The permeable core (1) has tiny ventilation holes that connect the air guide hole (4) to the working surface, which are diffusely distributed inside to form a uniform and stable argon gas curtain.

7. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The air curtain element is laid directly on the bottom of the tundish as an integral structure, independently forming the steel purification and flow field control structure in the tundish, replacing the traditional slag-blocking weir plate.

8. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The argon flow rate can be adjusted to keep the gas curtain strength and the degree of molten steel turbulence within a controllable range, avoiding agitation of the protective slag on the surface of the molten steel and preventing secondary oxidation and inclusion of impurities.

9. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The corundum spinel-chromium oxide system of the breathable core (1) gives it high-temperature corrosion resistance, thermal shock resistance and high open rate performance.

10. A novel air curtain element for intermediate tundishes according to claim 1, characterized in that: The breathable core (1) is a pre-made semi-finished product that is machine-pressed and then fired. The sealing layer (2) is formed by casting the breathable core (1) with sealing material after it is fixed on the mold, and then demolding and baking. The sealing layer (2) fully covers the bottom surface and four side surfaces along the outline of the breathable core (1), and only forms a continuous exposed air outlet working surface on the upper side.

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