Quick-change submersed nozzle with stable back pressure

Abstract

The utility model discloses a quick-change submersed nozzle with stable back pressure, and relates to the technical field of metallurgy. The submersed nozzle comprises a submersed nozzle body, a molten steel channel formed in the middle of the submersed nozzle body, a bowl part formed on the upper portion of the submersed nozzle body, a slag line and a side hole, the slag line and the side hole are formed in the lower portion of the submersed nozzle body, and a breathable layer, a sealing piece and an argon blowing device are arranged on the bowl part. The breathable layer is embedded in the top end of the bowl part and is flush with the top surface of the bowl part, the sealing pieces are embedded in the edges of the inner side and the outer side of the breathable layer and are flush with the top surface of the breathable layer, and the argon blowing device is used for conveying argon to the breathable layer. According to the quick-change submersed nozzle, the problem of inter-plate air suction between the upper nozzle and the submersed nozzle can be effectively solved, the stable argon flow is maintained, the argon blowing sealing effect is improved, non-oxide inclusions generated by air suction are reduced, and the quality of molten steel is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of metallurgy, in particular to a back pressure stable quick-change immersion nozzle. Background Art

[0002] During the continuous casting process, an immersed nozzle is used to connect the tundish to the crystallizer, which can prevent the secondary oxidation of the molten steel during the continuous casting process, prevent the crystallizer protection slag from being drawn into the molten steel, improve the heat flow state and smooth distribution state of the molten steel in the crystallizer, and is conducive to the solidification of the continuous casting billet into a uniform billet shell.

[0003] In order to improve production efficiency and the number of tundish continuous casting furnaces, quick-change immersion nozzles are widely used. During the use of quick-change immersion nozzles, due to the negative pressure generated by the flow of molten steel, the bottom of the upper nozzle and the upper plate surface of the change immersion nozzle are prone to oxygen and nitrogen absorption, which reduces the quality of molten steel. In order to reduce or avoid this phenomenon, fiber materials and argon blowing are generally used for sealing. During the use of argon blowing immersion nozzles, the problem of low or unstable back pressure between plates is more prominent, which is easy to cause air absorption between plates and oxidation steel penetration, resulting in premature shutdown accidents. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of the utility model is to provide a back pressure stable quick-change submerged nozzle. The utility model can effectively eliminate the problem of air suction between the upper nozzle and the submerged nozzle, maintain a quick-change submerged nozzle with a stable argon flow rate, which is conducive to improving the argon blowing sealing effect, reducing non-oxide inclusions caused by air suction, and improving the quality of molten steel.

[0005] In order to achieve the above object, the utility model is implemented through the following technical solutions:

[0006] The utility model provides a back-pressure stable quick-change immersion nozzle, comprising an immersion nozzle body, a molten steel channel formed in the middle of the immersion nozzle body, a bowl formed on the upper part of the immersion nozzle body, and a slag line and a side hole arranged at the lower part of the immersion nozzle body, the bowl being provided with a breathable layer, a sealing component and an argon blowing device, the breathable layer being inlaid on the top of the bowl and flush with its top surface, the sealing component being inlaid on the inner and outer side edges of the breathable layer and flush with its top surface, and the argon blowing device being used for conveying argon to the breathable layer.

[0007] Preferably, the air permeable layer is an annular structure with the same center as the molten steel channel, the radial distance between the air permeable layer and the inner and outer walls of the submerged nozzle body is not less than 10 mm, and the height of the air permeable layer is 30-50 mm. The air permeable layer parameter setting is related to the design of the argon blowing device, the back pressure requirements between the plates, etc. If the setting is unreasonable, it will affect the argon blowing effect (argon pressure), and then affect the sealing effect between the plates and the quality of the molten steel.

[0008] Preferably, the seal is an annular structure concentric with the molten steel channel, the radial distance between the seal and the inner and outer walls of the immersion nozzle body is not less than 10 mm, and the radial width of a single seal is 8 to 15 mm and the height is 12 to 23 mm. The setting of the seal parameters is related to the design of the argon blowing device and the back pressure requirements between the plates. If the setting is unreasonable, the rapid protection of argon gas and the stability of the seal cannot be achieved, which will affect the sealing effect between the plates and the quality of the molten steel.

[0009] Preferably, the argon blowing device includes an argon blowing nozzle and an airway, wherein the argon blowing nozzle is arranged on the outer wall of the bowl, and the airway is arranged inside the wrist; the air outlet of the airway is connected to the air permeable layer, and the air inlet thereof is connected to the argon blowing nozzle; the air outlet of the airway is located between the bottom surface of the sealing component and the bottom surface of the air permeable layer. Argon gas is diffusely blown into the space between the upper water inlet and the submerged water inlet through the airway and the air permeable layer, quickly forming a gas sealing zone, thereby avoiding air inhalation between the plates due to negative pressure, which leads to oxygen and nitrogen increase in the molten steel and the generation of non-oxide inclusions.

[0010] Preferably, the material of the air permeable layer is aluminum carbon with a volume density of 2.2-2.3 g / cm 3 , the apparent porosity is 15-18%. Among them, when the bulk density is too small and the apparent porosity is too large, the density of the breathable layer material is too low and the structure is loose, which affects the use effect; when the bulk density is too large and the apparent porosity is too small, the air permeability of the breathable layer material is low, which affects the argon blowing effect.

[0011] Preferably, the material of the seal is aluminum silicon carbon, with a volume density of 2.1-2.2 g / cm 3 , the apparent porosity is 10-12%; the thermal expansion rate of the seal during baking at 950-1100°C is 0.6-0.9%, and the thermal expansion rate of the seal during use at 1300-1500°C is 1.1-1.3%. Among them, when the bulk density is too small, the apparent porosity is too large, and the thermal expansion rate is too small, the seal material has low density, loose structure, and small thermal expansion rate, and cannot play a role in sealing and preventing air absorption. When the bulk density is too large, the apparent porosity is too small, and the thermal expansion rate is too large, the thermal expansion of the seal material is large, which affects the flatness of the board surface between the upper nozzle and the immersion nozzle, has an adverse effect on the protective casting, and even causes steel seepage between the plates.

[0012] Preferably, the center lines of the submerged nozzle body, bowl, and molten steel channel coincide; the slag line is located at 1 / 8-3 / 8 of the bottom of the submerged nozzle body, and the diameter of the slag line is the same as the diameter of the submerged nozzle body; the side hole is located at about 1 / 12-1 / 9 of the bottom of the submerged nozzle body, and two side holes are provided, and the two side holes are symmetrical about the center line of the submerged nozzle body; the diameters of the two side holes are both 40-55 mm. The slag line position setting parameters depend on the height of the molten steel slag level in the crystallizer and the parameters of the crystallizer liquid level automatic adjustment system. If the height setting is unreasonable, the service life of the submerged nozzle and the safety of continuous casting production will be affected. The side hole setting parameters are related to the billet pulling speed of the post-process of the crystallizer and the molten steel flow field in the crystallizer. If the setting is unreasonable, the continuous casting production rhythm and billet quality will be affected.

[0013] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0014] 1) In the utility model, a breathable layer is provided on the bowl of the quick-change immersion nozzle, which can diffusely blow the argon gas flowing in from the argon blowing nozzle and the airway into the space between the upper nozzle and the immersion nozzle plate to prevent secondary oxidation and nitridation of the molten steel, eliminate or reduce non-oxide inclusions in the molten steel caused by air suction, and improve the quality of the molten steel.

[0015] 2) In the utility model, a sealing member is provided on the bowl of the quick-change immersion nozzle. The sealing member material can expand to a certain extent when the immersion nozzle is baked online and used, thereby enhancing the sealing between the upper nozzle and the immersion nozzle plate, so that the back pressure can quickly reach the use requirements and remain stable, eliminating the air intake phenomenon caused by slow reaching of the predetermined pressure and unstable back pressure, improving the argon blowing sealing effect, reducing the degree of nozzle nodules, and effectively improving the quality of molten steel.

[0016] 3) The air permeable layer, sealing component and slag line material provided in the quick-change immersion nozzle of the utility model are integrally formed with the immersion nozzle body material, thereby improving the firmness of the combination between different materials and ensuring the stable use effect of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the utility model of the back pressure stable quick-change immersed water outlet.

[0018] Figure 2 It is a schematic diagram of the top view of the structure of the back pressure stable quick-change immersion nozzle of the utility model.

[0019] In the figure: 1-bowl; 2-argon blowing nozzle; 3-air channel; 4-sealing element; 5-breathable layer; 6-steel shell; 7-slag line; 8-molten steel channel; 9-immersed nozzle body; 10-side hole. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the utility model, the preferred implementation scheme of the utility model is described below in conjunction with specific embodiments. However, it should be understood that the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only used for illustrative purposes and cannot be understood as a limitation on this patent.

[0021] The utility model is further described in detail below in conjunction with the accompanying drawings to illustrate a back pressure stable quick-change immersion nozzle.

[0022] like Figure 1 and 2 As shown, a back pressure stable quick-change submerged nozzle comprises a submerged nozzle body 9, a bowl 1, a molten steel channel 8, a slag line 7 and a side hole 10. Among them, the center lines of the submerged nozzle body 9, the bowl 1 and the molten steel channel 8 coincide, the slag line 7 is located at 1 / 8-3 / 8 of the bottom of the submerged nozzle body 9, the diameter of the slag line 7 is the same as the diameter of the submerged nozzle body 9, the side hole 10 is located at 1 / 12-1 / 9 of the bottom of the submerged nozzle body 9, there are two side holes 10, the two side holes 10 are symmetrical about the center line of the submerged nozzle body 9, and the diameters of the two side holes 10 are both 40-55 mm.

[0023] In this example, the radial distance between the air permeable layer 5 and the outer wall and the inner wall of the submerged nozzle body 9 is not less than 10 mm, and the height of the air permeable layer 5 is 30 to 50 mm.

[0024] In this example, there are two seals 4, and the radial distance between the seals 4 and the outer wall and the inner wall of the immersion nozzle body 9 is not less than 10 mm, and the edge of the seal 4 is consistent with the edge of the air permeable layer 5. The radial width of a single seal 4 is 8 to 15 mm, and the height is 12 to 23 mm.

[0025] The material of the air permeable layer 5 in this example is aluminum carbon, and the volume density is 2.2-2.3 g / cm 3 , apparent porosity 15-18%; the material of the seal 4 is aluminum silicon carbon, and the volume density is 2.1-2.2g / cm 3 The apparent porosity is 10-12%. The thermal expansion rates during the online baking and use of the immersed nozzle (950-1100°C, 1300-1500°C) are 0.6-0.9% and 1.1-1.3% respectively.

[0026] The raw materials of the breathable layer material include, by weight: 60% to 77% of fused low-carbon brown corundum, 12% to 25% of fluorinated graphite, 3% to 8% of alumina powder, 3% to 8% of resin, 0.5% to 2.5% of diluent, and 0.8% to 2.5% of antioxidant.

[0027] The additional diluent is one or more alcohol organic solvents such as ethanol and ethylene glycol.

[0028] The antioxidant is one or more of boron carbide powder, silicon carbide powder, metal aluminum powder and metal silicon powder.

[0029] The raw materials of the sealing material include, by weight, fused low-carbon brown corundum 49% to 70%, andalusite 6% to 12%, pyrophyllite 8% to 15%, expanded graphite 9% to 25%, alumina powder 3% to 7%, phenolic resin 4% to 8%, and antioxidant 0.8% to 2.5%.

[0030] The antioxidant is one or more of boron carbide powder, silicon carbide powder, metal aluminum powder and metal silicon powder.

[0031] A method for manufacturing a quick-change immersion nozzle with stable back pressure, comprising the following steps:

[0032] 1) Ingredients: Mix the raw materials according to the weight ratio according to the ingredient list;

[0033] 2) Mixing and granulation: put the prepared raw materials into a granulator for mixing and granulation;

[0034] 3) Material trapping: Place the prepared materials in the material trapping room, ensure that the temperature in the material trapping room is between 20 and 25°C, the humidity is less than 38%, and the material trapping time is 7 to 15 hours;

[0035] 4) Molding: Add the trapped immersion nozzle body material, bowl material, slag line material, air permeable layer material, and sealing material into the mold respectively, and mold them in an isostatic pressing equipment with a molding pressure of 130-150MPa;

[0036] 5) Drying: Dry the formed immersion nozzle in a drying kiln at 220-250℃ for 18-24h;

[0037] 6) Firing: Place the immersion nozzle into a firing kiln in a reducing atmosphere and keep it at 1050-1150℃ for 5-6 hours;

[0038] 7) Mechanical processing: Turn the fired immersion nozzle according to the requirements of the drawing;

[0039] 8) Coating: Evenly apply a layer of anti-oxidation coating on the outside of the immersion nozzle, with a coating thickness of 0.1-0.2mm;

[0040] 9) Flaw detection: Perform X-ray flaw detection on the immersion nozzle;

[0041] 10) Packaging: Finished products will be packaged after passing the inspection.

[0042] Table 1 is a list of raw material addition amounts for each embodiment and comparative example of the breathable layer material of the utility model.

[0043] Table 2 is a list of raw material addition amounts for each embodiment and comparative example of the seal of the utility model.

[0044] Table 3 shows the main process parameters of various embodiments and comparative examples of the present invention.

[0045] Table 4 is a table of the performance test results of various embodiments and comparative examples of the breathable layer material of the present invention.

[0046] Table 5 is a list of performance test results of various embodiments and comparative examples of the seal of the utility model.

[0047] Table 1 (Wt, %)

[0048]

[0049]

[0050] Table 2 (Wt, %)

[0051]

[0052] Table 3

[0053]

[0054] Table 4

[0055]

[0056]

[0057] Table 5

[0058]

[0059] As shown in Examples 1 to 3 of Tables 1, 2, and 3, within the amount of raw materials added as specified in the utility model, an appropriate amount of fused low-carbon brown corundum, graphite fluoride, alumina powder, resin, a diluent, and an antioxidant are added to the breathable layer material, and an appropriate amount of fused low-carbon brown corundum, andalusite, pyrophyllite, expanded graphite, alumina powder, resin, and an antioxidant are added to the sealing member; while the process parameters such as the trapped material temperature, trapped material time, molding pressure, firing temperature, and insulation time are well controlled, a quick-change immersed nozzle can be prepared that can effectively eliminate the problem of air suction between the plates between the upper nozzle and the immersed nozzle, and maintain a stable argon flow rate, which is beneficial to improving the argon blowing sealing effect, reducing non-oxide inclusions caused by air suction, and improving the quality of molten steel.

[0060] In contrast, for comparative examples 1 to 2 in which the amount of raw material added and the production process are not controlled, the quick-change submerged nozzle cannot effectively eliminate the problem of air intake between the plates between the upper nozzle and the submerged nozzle, and maintains a stable argon flow rate, which is not conducive to improving the argon blowing sealing effect and reducing non-oxide inclusions caused by air intake, thereby reducing the quality of molten steel and failing to meet the performance requirements of the product.

[0061] According to the description and drawings of the utility model, those skilled in the art can easily manufacture or use a back-pressure stable quick-change submerged water outlet of the utility model, and can produce the positive effects recorded in the utility model.

[0062] Unless otherwise specified, in the present invention, the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood in conjunction with the drawings and according to specific circumstances.

[0063] Unless otherwise specified and limited, in the present invention, the terms "disposed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] The above is only a preferred embodiment of the utility model, but the utility model is not limited to the above specific embodiments. Ordinary technicians in this field can also make some modifications, supplements or replace them with similar methods without departing from the principle of the utility model, which should also be regarded as the protection scope of the utility model.

Claims

1. A back pressure stable quick-change immersion nozzle, comprising an immersion nozzle body (9), a molten steel channel (8) formed in the middle of the immersion nozzle body (9), a bowl (1) formed on the upper part of the immersion nozzle body (9), and a slag line (7) and a side hole (10) arranged on the lower part of the immersion nozzle body, characterized in that: The bowl portion (1) is provided with a breathable layer (5), a sealing member (4) and an argon blowing device. The breathable layer (5) is embedded in the top of the bowl portion (1) and is flush with its top surface. The sealing member (4) is embedded in the inner and outer side edges of the breathable layer (5) and is flush with its top surface. The argon blowing device is used to transport argon gas to the breathable layer (5).

2. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The air permeable layer (5) is an annular structure cocentric with the molten steel channel (8), the radial distance between the air permeable layer (5) and the inner and outer walls of the submerged nozzle body (9) is not less than 10 mm, and the height of the air permeable layer (5) is 30 to 50 mm.

3. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The sealing member (4) is an annular structure cocentric with the molten steel channel (8), the radial distance between the sealing member (4) and the inner and outer walls of the immersion nozzle body (9) is not less than 10 mm, and the radial width of a single sealing member (4) is 8 to 15 mm and the height is 12 to 23 mm.

4. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The argon blowing device comprises an argon blowing nozzle (2) and an air channel (3); the argon blowing nozzle (2) is arranged on the outer wall of the bowl portion (1), and the air channel (3) is arranged inside the bowl portion; the air outlet of the air channel (3) is connected to the air permeable layer (5), and the air inlet thereof is connected to the argon blowing nozzle (2); the air outlet of the air channel (3) is located between the bottom surface of the sealing component (4) and the bottom surface of the air permeable layer (5).

5. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The material of the air permeable layer (5) is aluminum carbon, and the volume density is 2.2-2.3 g / cm 3 , the apparent porosity is 15-18%.

6. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The material of the sealing element (4) is aluminum silicon carbon, and the volume density is 2.1-2.2 g / cm 3 , the apparent porosity is 10-12%; the thermal expansion rate of the sealing member (4) during baking at 950-1100°C is 0.6-0.9%, and the thermal expansion rate of the sealing member (4) during use at 1300-1500°C is 1.1-1.3%.

7. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The slag line (7) is located at 1 / 8-3 / 8 of the bottom of the submerged nozzle body (9), and the diameter of the slag line (7) is the same as the diameter of the submerged nozzle body (9).

8. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The side hole (10) is located at 1 / 12-1 / 9 of the bottom of the immersion nozzle body (9), and two side holes (10) are provided, and the two side holes (10) are symmetrical about the center line of the immersion nozzle body (9).

9. The back pressure stable quick-change submerged nozzle according to claim 8, characterized in that: The diameters of the two side holes (10) are both 40-55 mm.

10. The back pressure stable quick-change submerged nozzle according to claim 1, characterized in that: The center lines of the submerged nozzle body (9), the bowl (1) and the molten steel channel (8) coincide with each other.

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