Bottom blowing ventilation type turbulence suppressor for continuous casting

Abstract

The utility model discloses a bottom blowing ventilation type turbulence suppressor for continuous casting, which comprises a cylindrical body (1), the cylindrical body (1) comprises a body side wall (11) and an impact bottom plate (12) which are connected, a step table (2) is arranged in the impact bottom plate (12), a square ventilation element (3) is embedded at the upper part of the step table (2), and an air chamber (4) and an air passage (5) which are connected are arranged at the lower part of the step table (2). And the ventilation element (3) is communicated with an external air source through a standard fixed-length metal ventilation joint (6). The device has the advantages that the device has a bottom blowing ventilation function, a bubble generation mode is beneficial to formation of a large number of independently nucleated small dispersed bubbles, the diameter is 0.1-2mm, the bubbles float upwards in an air curtain shape, the probability that the bubbles collide with inclusions and float upwards to be removed is increased, meanwhile, the turbulence energy strength of incident flow strands of a steel ladle is further counteracted, and the service life of the steel ladle is prolonged. And the plunger flow proportion is increased, and erosion to the bottom of the turbulence suppressor is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of refractory materials, in particular to a bottom-blowing air-permeable turbulence inhibitor for continuous casting. Background Art

[0002] In recent years, the steel industry has imposed increasingly strict requirements on the cleanliness of molten steel. As an intermediate buffer container for high-temperature molten steel to finally enter the mold from the ladle and solidify into a solid steel billet, the continuous casting tundish plays a crucial role in connecting the preceding with the following. The process of molten steel pouring from the ladle into the impact zone of the tundish is accompanied by intense stirring and reaction among the gas-solid-liquid multiphases of "molten steel - tundish slag - air - refractory material", which is an important reason for the secondary pollution of molten steel. The use of a turbulence inhibitor can effectively reduce the impact kinetic energy and the reaction tendency among multiphases. By restricting the flow direction of the injected molten steel, the side wall of the main body blocks the molten steel, and the return flow collides and mixes with the subsequent injected molten steel. This process continues continuously, thereby reducing the turbulence intensity and stirring energy, calming the molten pool and increasing the proportion of plug flow at the same time.

[0003] Inclusions in molten steel mainly include two types: one is endogenous inclusions, mainly from tiny deoxidation products generated during the steelmaking stage, with a size less than 50um; the other is exogenous inclusions, mainly from slag or refractory materials involved in the molten steel, with a size greater than 50um. The floating and removal of inclusions follow Archimedes' principle, that is, in the molten steel bath, the main component of inclusions is non-metallic oxide, and its density is less than that of molten steel. Therefore, inclusions have the tendency to float from the molten pool to the steel-slag interface by their own buoyancy and are finally captured and absorbed by the tundish slag. However, under the condition of small inclusion size, such as less than 20um, in addition to the action of buoyancy and gravity, the interfacial tension between it and molten steel cannot be ignored. Therefore, the removal effect of small inclusions in molten steel is not ideal. Summary of the Utility Model

[0004] The purpose of the utility model is to solve the problems of insufficient removal effect of inclusions and purification of molten steel, large impact kinetic energy of the incident jet, and insufficient calming effect of the molten pool in the existing turbulence inhibitor. A bottom-blowing air-permeable turbulence inhibitor for continuous casting is provided, which improves the removal effect of small inclusions, fully purifies the molten steel, improves the cleanliness, reduces the impact intensity of the incident jet and the erosion of the main body, and is conducive to calming the molten pool and increasing the proportion of plug flow.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A bottom-blowing air-permeable turbulence inhibitor for continuous casting, comprising a body and an air curtain filter that cooperate with each other. Among them, the body is a cylindrical structure, which includes a connected body side wall and an impact bottom plate. A stepped platform is provided inside the impact bottom plate. A square air-permeable element is embedded in the upper part of the stepped platform, and an air chamber and an air passage are provided in the lower part and are connected. The air-permeable element is communicated with an external gas source through a metal ventilation joint of a standard fixed length.

[0007] Further, the body side wall and the impact bottom plate are integrally formed by casting. The air curtain filter is embedded in the impact bottom plate. The air-permeable element of the air curtain filter is a machine-pressed forming structure, which is independently embedded in the upper part of the stepped platform, and the periphery is filled and sealed with fire clay.

[0008] Further, the air-permeable element is located at the bottom of the body and the impact point. The side length of the air-permeable element is smaller than the diameter of the impact bottom plate, and the thickness of the air-permeable element is 50-100 mm.

[0009] Further, the air-permeable element is a breathable material, its porosity ≥ 25%, the bubble diameter formed by the air-permeable element is 0.1-2 mm, and the bubbles float up in the shape of an air curtain structure.

[0010] Further, the air chamber is composed of a cavity surrounded by the bottom of the air-permeable element and the lower part of the stepped platform. The height of the air chamber is 20-50% of the thickness of the air-permeable element.

[0011] Further, the air chamber is located below the air-permeable element and uses a stepped structure to position and support the air-permeable element. The step height H of the stepped platform is 20-50 mm, and the protruding length d on both sides of the stepped platform is 20-100 mm.

[0012] Further, the body is made of high-alumina or high-magnesia casting material, and the air-permeable element is made of aluminum-carbon and magnesia-carbon machine-pressed materials.

[0013] Further, the metal ventilation joint is made of carbon steel, and its connection method is a standard fixed-length threaded structure connector.

[0014] Compared with the prior art, the advantages of the technical solution of the present utility model are specifically as follows:

[0015] (1) The turbulence inhibitor of the present utility model embeds an air curtain filter with an air-permeable structure at the impact bottom, so that it has a bottom-blowing air-permeable function. Inert gas is blown in through an external connector and an internal air chamber, and finally fine and dispersed bubbles are formed through the air-permeable element;

[0016] (2) The turbulence inhibitor of the present utility model has a bottom-blowing air-permeable function, which is beneficial to the collision and adsorption of inclusions in the molten steel with bubbles and their floating removal, thereby improving the purity of the molten steel and improving the quality;

[0017] (3) The turbulence inhibitor of the present utility model has a bottom-blowing air-permeable function. The upward floating direction of the air curtain is opposite to the incoming flow of the ladle, which is beneficial to further reducing the impact kinetic energy of the incoming jet, reducing the impact and erosion on the bottom of the turbulence inhibitor, and prolonging the service life.

[0018] (4) The air-permeable connection mode of the turbulence inhibitor of the present utility model adopts standard metric thread connection. The air chamber structure and the air-permeable element structure are simple, easy to manufacture, convenient for installation and positioning, and safe and reliable during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the internal structure diagram of the bottom-blowing air-permeable turbulence inhibitor for continuous casting of the present utility model;

[0020] Figure 2 It is the top view of the bottom-blowing air-permeable turbulence inhibitor for continuous casting of the present utility model. DETAILED DESCRIPTION OF THE INVENTION Embodiment

[0021] To make the present utility model more clearly understood, the following further describes a bottom-blowing air-permeable turbulence inhibitor for continuous casting of the present utility model in conjunction with the drawings. The specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0022] Refer to Figure 1 and Figure 2 A bottom-blowing air-permeable turbulence inhibitor for continuous casting includes a body 1 and an air curtain filter that cooperate with each other, and is characterized in that:

[0023] The body 1 is of a cylindrical structure, which includes a connected body side wall 11 and an impact bottom plate 12. The two are integrally formed by casting, and high-alumina or high-magnesia casting materials are used;

[0024] A stepped platform 2 is provided inside the impact bottom plate 12. A square air-permeable element 3 is embedded in the upper part of the stepped platform 2, and an air chamber 4 and an air passage 5 are provided in the lower part. The air-permeable element 3 is communicated with an external air source through a standard-sized metal air vent joint 6. The metal air vent joint 6 is made of carbon steel, and its connection mode is a standard-sized threaded structure connector;

[0025] The air-permeable element 3 of the air curtain filter is made of aluminum-carbon and magnesia-carbon machine-pressed materials. It is independently embedded in the upper part of the stepped platform 2 and is filled and sealed with fire clay around. The air-permeable element 3 is located near the bottom of the inhibitor body and the impact point. The side length of the air-permeable element 3 is smaller than the diameter of the impact bottom plate 12, and the thickness of the air-permeable element 3 is 50 - 100 mm;

[0026] The air chamber 4 is composed of a cavity surrounded by the bottom of the air-permeable element 3 and the lower part of the stepped platform 2. The height of the air chamber 4 is 20 - 50% of the thickness of the air-permeable element 3.

[0027] In this embodiment, the breathable element 3 is made of a breathable material with a porosity of ≥ 25%. The bubble diameter formed by the breathable element 3 is 0.1 - 2 mm, and the rising bubbles present a curtain-like structural morphology.

[0028] In this embodiment, the air chamber 4 is located below the breathable element 3 and uses a stepped structure to position and support the breathable element 3. The step height H of the stepped platform 2 is 20 - 50 mm, and the protruding length d on both sides of the stepped platform 2 is 20 - 100 mm.

[0029] The body 1 of the present utility model includes a body side wall 11 and an impact bottom plate 12, which are integrally formed by casting. A space is reserved at the bottom. By using a stepped partition, the air curtain filter includes a breathable element 3, an air chamber 4, and a metal ventilation joint 6. The upper part of the stepped platform is used to position and fix the breathable element 3, and the lower part is the air chamber 4 and the air duct 5. The breathable element 3 is in contact with the molten steel. During operation, the inert gas is connected through the metal ventilation joint 6 outside the breathable element, and the blown-in gas is "divided" into fine bubbles with a diameter of 0.1 - 2 mm and blown into the molten pool in the stabilizer cavity.

[0030] By compoundly embedding a breathable functional component in the bottom plate of the traditional turbulence inhibitor, on the one hand, the blown-in inert gas forms dispersed bubbles with an independent nucleation diameter of 0.1 - 2 mm through the breathable element. During the upward floating process of a large number of bubbles, an air curtain filter is formed, which promotes the continuous collision and adsorption between the bubbles and the inclusions. Since the bubble size is much larger than the inclusions, especially micro-inclusions, and the density of the bubbles is much smaller than that of the molten steel, the inclusions in the molten steel are more likely to be separated, captured, and removed by floating with the bubbles as the attachment medium, thereby achieving the purpose of further purifying the molten steel and improving the cleanliness. On the other hand, the upward floating process of the air curtain forms a countercurrent with the downward flow, further offsetting the turbulent kinetic energy intensity of the ladle incident jet flow, which is beneficial to reducing the impact intensity of the incident jet flow and the erosion of the body, and is more conducive to calming the molten pool and increasing the proportion of the plunger flow.

[0031] In addition to the above embodiments, the present utility model can also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present utility model.

Claims

1. A bottom-blowing air-permeable turbulence suppressor for continuous casting, comprising a body (1) and an air curtain filter that cooperate with each other, characterized in that: The main body (1) is a cylindrical structure, comprising a connected main body side wall (11) and an impact base plate (12), wherein a stepped platform (2) is provided inside the impact base plate (12), wherein a square air permeable element (3) is embedded in the upper part of the stepped platform (2), and a connected air chamber (4) and an air duct (5) are provided in the lower part, and the air permeable element (3) is connected to an external air source via a standard fixed-length metal vent joint (6).

2. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1, characterized in that: The body side wall (11) and the impact bottom plate (12) are cast into an integral structure, an air curtain filter is embedded in the impact bottom plate (12), and the air permeable element (3) of the air curtain filter is a machine-pressed structure, which is independently embedded in the upper part of the step platform (2) and is sealed and fixed around with fire clay.

3. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The air permeable element (3) is located at the bottom of the body and at the location of the impact point, the side length of the air permeable element (3) is smaller than the diameter of the impact bottom plate (12), and the thickness of the air permeable element (3) is 50-100 mm.

4. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The air permeable element (3) is made of an air permeable material with a porosity of ≥25%. The diameter of the bubbles formed by the air permeable element (3) is 0.1-2 mm, and the bubbles float upward to form an air curtain-like structure.

5. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The air chamber (4) is composed of a cavity surrounded by the bottom of the air permeable element (3) and the lower part of the stepped platform (2), and the height of the air chamber (4) is 20-50% of the thickness of the air permeable element (3).

6. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The air chamber (4) is located below the air permeable element (3), and adopts a step structure to position and support the air permeable element (3). The step height H of the step platform (2) is 20 to 50 mm, and the protruding length d on both sides of the step platform (2) is 20 to 100 mm.

7. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The body (1) is a high-alumina or high-magnesia casting material, and the air-permeable element (3) is an aluminum-carbon or magnesium-carbon machine-pressed material.

8. The bottom-blowing air-permeable turbulence suppressor for continuous casting according to claim 1 or 2, characterized in that: The metal vent joint (6) is made of carbon steel, and its connection method is a standard fixed-length threaded structural connector.

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