Super-large section vertical semi-continuous casting round billet submersed nozzle

Abstract

The invention provides a super-large section vertical semi-continuous casting round billet submersed nozzle, and relates to the technical field of continuous casting crystallizers. The submersed nozzle comprises a nozzle body. The nozzle body is of a tubular structure, and one end of the nozzle body is closed. A plurality of water outlet holes are formed in the circumferential side wall of the closed end of the nozzle main body and are symmetrically distributed by taking the axis of the pipeline as the center. And the axial length of the water outlet hole in the nozzle main body is smaller than the circumferential length of the nozzle main body. From the inside to the outside of the nozzle main body, the two side walls of the water outlet hole in the width direction gradually incline away from the closed end. The submersed nozzle can guide molten steel jet flow to diffuse in the radial direction, the molten steel jet flow is more fully mixed with surrounding molten steel, formation of local high-temperature areas and low-temperature areas is reduced, and the situation that the thickness of a blank shell is different due to uneven temperature fields is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting mold, and more particularly, to an immersed nozzle for vertical semi-continuous casting of super-large cross-section round billets. Background Art

[0002] Super-large cross-section round billets are widely used in fields such as large-scale mechanical equipment, shipbuilding, and nuclear power engineering. Their high strength, excellent internal quality, and performance all pose higher requirements for the production process. As one of the core equipment of the vertical semi-continuous casting technology for super-large cross-section round billets, the design of the immersed nozzle in the continuous casting mold is crucial for the flow behavior of molten steel and the quality of the cast billet.

[0003] There are some deficiencies in the application of the immersed nozzle used in traditional continuous casting in the vertical semi-continuous casting process of super-large cross-section round billets. For example, the direction of the jet ejected from the water hole is not easy to control, which will cause a destructive impact on the thin billet shell formed in the initial stage of solidification; and due to the very large cross-sectional size, there is a high risk of local liquid surface temperature being too low, and the protective slag not being effectively melted and crusting. Summary of the Invention

[0004] The problem solved by the present invention is that the direction of the jet ejected from the water hole of the existing immersed nozzle is not easy to control, which will cause a destructive impact on the thin billet shell formed in the initial stage of solidification; and due to the very large cross-sectional size, there is a high risk of local liquid surface temperature being too low, and the protective slag not being effectively melted and crusting.

[0005] To solve the above problems, the present invention provides an immersed nozzle for vertical semi-continuous casting of super-large cross-section round billets, including a nozzle body. The nozzle body is in a tubular structure, and one end is a closed end. A plurality of water outlet holes are opened on the circumferential side wall of the closed end of the nozzle body, and the plurality of water outlet holes are symmetrically distributed around the axis of the pipeline. The length of the water outlet hole in the axial direction of the nozzle body is less than the length in the circumferential direction of the nozzle body. From the inside to the outside of the nozzle body, the two side walls of the water outlet hole in the width direction gradually incline away from the closed end.

[0006] Optionally, the length-width ratio of the water outlet hole is 3:1 to 4:1.

[0007] Optionally, the water outlet hole is rectangular or oval.

[0008] Optionally, the number of the water outlet holes is 5.

[0009] Optionally, the included angle between the two side walls of the water outlet hole in the width direction and the cross-section of the nozzle body is θ 。 The calculation formula for the included angle θ is:

[0010] In the formula, k and c are empirical coefficients, h is the depth of the nozzle inserted into the molten steel, and D is the diameter of the round billet.

[0011] Optionally, the total area of the multiple water outlet holes is not greater than 2‰ of the cross-sectional area of the round billet.

[0012] Optionally, the wall thickness of the nozzle body does not exceed 20 mm.

[0013] Optionally, the material of the nozzle body is alumina.

[0014] Optionally, it further includes a connecting section. The connecting section is provided with a circulation hole. The two ends of the connecting section are respectively connected to one end of the nozzle body far away from the water outlet hole and the outlet seat brick of the continuous casting tundish.

[0015] Optionally, the connecting section and the nozzle body are integrally formed.

[0016] The beneficial effects of the present invention are as follows: By setting one end of the nozzle body of the immersion nozzle of the present invention as a closed end, and evenly arranging circumferentially distributed water outlet holes on the side wall of the closed end, the flow direction of the molten steel can be effectively guided, avoiding the disorder caused by the direct outflow of the molten steel from the bottom of the nozzle, ensuring the uniformity of the outflow of the molten steel, and contributing to improving the quality stability of round billet casting. At the same time, the shape and extension direction of the water outlet holes are defined. The shape of the water outlet holes with a short radial length and a long circumferential length can make the molten steel form a relatively wide and gentle flow distribution in the mold, reduce the local flow velocity difference, and ensure that the temperature and velocity fields of the molten steel in the mold are more uniform; it can effectively reduce the impact force of a single fluid jet, reducing the risk of damage to the primary shell; it can also make the molten steel flow cover a larger liquid surface range, contributing to the full melting of the mold powder, improving the effect of the mold powder, and preventing local over-thickness or over-thinness of the slag layer; the water outlet holes designed to be inclined from the closed end of the nozzle body to the other end can generate an upward molten steel jet, enhancing the fluidity and melting efficiency of the mold powder layer. Especially under the condition of low pouring speed in vertical semi-continuous casting, it is more conducive to the rapid formation of a uniformly covered slag film layer by the mold powder, and the upward angle can guide the molten steel jet to diffuse radially, mixing more fully with the surrounding liquid steel, reducing the formation of local high-temperature and low-temperature regions, and avoiding the difference in shell thickness caused by uneven temperature field. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the immersion nozzle of the present invention; Figure 2 is a cross-sectional view of the immersion nozzle of the present invention; Figure 3 is Figure 2 a partial enlarged view at A in Figure 4 is Figure 2 the front view of Figure 5 is Figure 4 a partial enlarged view at B in Figure 6 It is the contour map of the flow field distribution in the mold of the submerged nozzle for the φ1600mm extra-large cross-section vertical semi-continuous casting round billet; Figure 7 It is the contour map of the distribution at the meniscus of the submerged nozzle for the φ1600mm extra-large cross-section vertical semi-continuous casting round billet.

[0018] Explanation of the reference numerals in the drawings: 1. Nozzle body; 2. Water outlet hole; 3. Connection section. Specific embodiments

[0019] To make the above-mentioned objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0020] The Z-axis in the drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z-axis represents the upper side, and the negative direction of the Z-axis represents the lower side; the X-axis in the drawings represents the horizontal direction and is specified as the front and back position, and the positive direction of the X-axis represents the front side, and the negative direction of the X-axis represents the back side; the Y-axis in the drawings represents the left and right position, and the positive direction of the Y-axis represents the left side, and the negative direction of the Y-axis represents the right side. At the same time, it should be noted that the above-mentioned meanings represented by the Z-axis, Y-axis, and X-axis are only for facilitating the description of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0021] The term "including" and its variants used herein are open-ended, that is, "including but not limited to"; the term "based on" is "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiment". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules, or units, and are not used to limit the order of the functions performed by these devices, modules, or units or their interdependent relationships.

[0022] It should be noted that the modifiers "one" and "more than one" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless clearly specified otherwise in the context, it should be understood as "one or more".

[0023] As Figures 1-5 shown, an immersed nozzle for an extra-large cross-section vertical semi-continuous casting round billet provided by an embodiment of the present invention includes a nozzle body 1. The nozzle body 1 has a tubular structure, and one end is a closed end. A plurality of water outlet holes 2 are formed on the circumferential side wall of the closed end of the nozzle body 1, and the plurality of water outlet holes 2 are symmetrically distributed around the pipe axis. The length of the water outlet hole 2 in the axial direction of the nozzle body 1 is less than the length in the circumferential direction of the nozzle body 1. From the inside to the outside of the nozzle body 1, the two side walls of the water outlet hole 2 in the width direction gradually incline away from the closed end.

[0024] The two side walls of the water outlet hole 2 in the width direction, that is, the two side walls along the length direction of the water outlet hole 2; from the inside to the outside of the nozzle body 1, the two side walls of the water outlet hole 2 in the width direction gradually incline away from the closed end, that is, from the inside of the pipe to the outside of the pipe, the water outlet direction of the water outlet hole 2 gradually inclines away from the closed end.

[0025] Specifically, the core component of this immersed nozzle is the nozzle body 1, which has a tubular structure and one end is a closed end. During the actual casting process, the design of the closed end can effectively guide the flow direction of the molten steel and avoid the disorder caused by the direct outflow of the molten steel from the bottom of the nozzle. On the circumferential side wall of the closed end of the nozzle body 1, a plurality of water outlet holes 2 are evenly distributed, and these water outlet holes 2 are symmetrically distributed around the pipe axis, ensuring the uniformity of the molten steel outflow and helping to improve the quality stability of the round billet casting. The length of the water outlet hole 2 in the axial direction of the nozzle body 1 is less than the length in the circumferential direction of the nozzle body 1, indicating that the width in the axial direction is less than the length in the circumferential direction, that is, the shape of the water outlet hole 2 is approximately a flat hole in the transverse (circumferential) direction, which is completely different from the side holes (similar to round holes) with a low length-width ratio in the vertical direction (axial direction) of conventional continuous casting. The flat hole can make the molten steel form a relatively broad and gentle flow distribution in the mold, reduce the local flow velocity difference, and ensure that the temperature and velocity fields of the molten steel in the mold are more uniform. The water outlet holes 2 are arranged obliquely, and the inclination direction is from the closed end of the nozzle body 1 to the other end, which can generate an upward molten steel jet. It can enhance the fluidity and melting efficiency of the mold powder layer. Especially under the condition of low pouring speed in vertical semi-continuous casting, it is more conducive to the rapid formation of a uniformly covered slag film layer of the mold powder. In addition, the upward angle guides the molten steel jet to diffuse radially, mixes more fully with the surrounding molten steel, reduces the formation of local high-temperature and low-temperature zones, and avoids the difference in the thickness of the billet shell caused by uneven temperature fields.

[0026] The submerged nozzle of the present invention has one end of the nozzle body 1 set as a closed end, and water outlet holes 2 evenly distributed in the circumferential direction are uniformly opened on the side wall of the closed end. It can effectively guide the flow direction of molten steel, avoid the disorder caused by the direct outflow of molten steel from the bottom of the nozzle, and ensure the uniformity of the outflow of molten steel, which helps to improve the quality stability of round billet casting. At the same time, the shape and extension direction of the water outlet hole 2 are defined. The shape of the water outlet hole 2 with a short radial length and a long circumferential length can make the molten steel form a relatively wide and gentle flow distribution in the mold, reduce the local flow velocity difference, and ensure that the temperature and velocity fields of the molten steel in the mold are more uniform; it can effectively reduce the impact force of a single fluid jet and reduce the risk of damage to the primary shell; it can also include making the molten steel flow cover a larger liquid surface range, which helps to fully melt the mold powder, improve the effect of the mold powder, and prevent the local thickness of the slag layer from being too thick or too thin; the water outlet hole 2 designed to be inclined from the closed end of the nozzle body 1 to the other end can generate an upward molten steel jet, enhance the fluidity and melting efficiency of the mold powder layer. Especially under the condition of low pouring speed in vertical semi-continuous casting, it is more conducive to the rapid formation of a uniformly covered slag film layer by the mold powder, and the upward angle can guide the molten steel jet to diffuse radially and mix more fully with the surrounding molten steel, reducing the formation of local high-temperature and low-temperature zones and avoiding the difference in shell thickness caused by uneven temperature fields. Optionally, the length-width ratio of the water outlet hole 2 is 3:1 to 4:1.

[0027] Specifically, setting the length-width ratio of the water outlet hole 2 to 3:1 - 4:1 is a key parameter obtained through comprehensive consideration of various factors such as the flow characteristics of molten steel, the flow field distribution of molten steel in the mold, and the quality requirements of ultra-large section round billets. From the perspective of fluid mechanics, the water outlet hole 2 with this ratio can effectively control the outflow speed and direction of molten steel. When molten steel flows out from the water outlet hole 2 with a length-width ratio within this range, compared with orifice types with other ratios, it can form a relatively stable and directional flow stream. During the vertical semi-continuous casting process, this flow stream helps to reduce the surface fluctuation of molten steel and the possibility of vortex generation, thereby avoiding the entrainment of the mold powder on the molten steel surface into the molten steel interior and effectively preventing the generation of slag inclusion defects.

[0028] Optionally, the water outlet hole 2 is rectangular or elliptical.

[0029] Specifically, the water outlet hole 2 is designed in two optional shapes: rectangular or oval. The choice of these two shapes is based on different casting process requirements and the molten steel flow characteristics, and can play a unique advantage in the production of ultra-large cross-section vertical semi-continuous casting round billets. From the perspective of fluid mechanics, the rectangular water outlet hole 2 has a regular geometric structure, and its straight-edge design enables the molten steel to form a relatively regular flow when flowing out. In scenarios where strict control of the molten steel flow direction is required during casting, the rectangular water outlet hole 2 performs excellently. For example, when producing alloy steel round billets with extremely high requirements for the uniformity of the internal tissue structure, the rectangular water outlet hole 2 can, with its stable flow output, make the molten steel form a stable circulating flow in the mold, promote the uniform mixing of the components in the molten steel, and reduce the segregation phenomenon. In addition, the straight-edge structure of the rectangular water outlet hole 2 is relatively simple in processing and manufacturing. The dimensional accuracy can be precisely controlled through numerical control processing equipment, which is convenient for mass production and can effectively reduce the manufacturing cost. The oval water outlet hole 2 has unique hydrodynamic characteristics. Its smooth edge design can effectively reduce the resistance when the molten steel flows out and reduce the generation of turbulence. When casting high-viscosity steel grades, such as high-carbon steel round billets, the oval water outlet hole 2 can better adapt to the viscous characteristics of the molten steel, enabling the molten steel to flow out in a relatively gentle manner and avoiding excessive fluctuations in the liquid level in the mold due to overly violent molten steel flow. At the same time, during the flow of the molten steel, the oval water outlet hole 2 helps to guide the molten steel to form a spiral flow field, which can enhance the scouring effect of the molten steel on the mold wall, prevent the uneven growth of the billet shell on the mold wall, and thus improve the surface quality of the round billet. Moreover, when the oval structure is subjected to the scouring of high-temperature molten steel, the stress distribution is more uniform. Compared with other shapes, it has better erosion resistance and can extend the service life of the submerged nozzle. During the actual production process, the shape of the water outlet hole 2 can be flexibly selected according to the specific round billet specifications, steel grade characteristics, and casting process requirements. By reasonably selecting the two shapes of the water outlet hole 2, the precise control of the molten steel flow state can be achieved, thereby ensuring the high-quality production of ultra-large cross-section vertical semi-continuous casting round billets.

[0030] Optionally, the number of the water outlet holes 2 is 5.

[0031] Specifically, the number of the water outlet holes 2 is determined by comprehensively considering various factors such as the distribution of molten steel flow rate, the uniformity of the flow field in the mold, the quality of round billets, and production efficiency. The preferred number is 5. Of course, it can also be set to 4, 6, 7, etc. according to the specific shape of the nozzle body 1. For example, when the nozzle body 1 is a cylindrical tubular structure, 4, 5, 6, or 7 water outlet holes 2 can be evenly distributed in the circumferential direction of the nozzle body 1; when the nozzle body 1 is a regular polygon prism pipe, the number of the water outlet holes 2 is preferably corresponding to the sides of the prism pipe. Analyzing from the aspect of the uniformity of the flow field in the mold, the 5 water outlet holes 2 are symmetrically distributed with the pipe axis as the center, which can form a relatively uniform flow field in the mold. When the molten steel flows out from these 5 water outlet holes 2, they interact with each other in the mold to form a stable and symmetric circulation flow. This uniform flow field helps the inclusions in the molten steel to be evenly distributed and float to the surface of the molten steel, improving the purity of the round billet.

[0032] Optionally, the total area of the multiple water outlet holes 2 is not greater than 2‰ of the cross-sectional area of the round billet.

[0033] Specifically, restricting the total opening area of the side water holes can precisely control the flow rate of the molten steel flowing into the mold per unit time. If the total area of the water outlet holes 2 is too large, the molten steel will flow out of the nozzle too fast, forming a strong downward impact flow in the mold, resulting in violent fluctuations in the molten steel surface level and even generating vortices. This unstable flow field is extremely likely to entrain the surface protective slag into the molten steel interior, forming slag inclusion defects; at the same time, the high-speed impact flow will also intensify the erosion of the molten steel on the mold wall, accelerating the wear of the mold and affecting its service life. On the contrary, if the total area is too small, the molten steel flows slowly, and it is difficult to form an effective circulating flow field in the mold, which is not conducive to the floating and discharging of inclusions in the molten steel and may lead to quality problems such as inclusion aggregation inside the round billet. Controlling the total area within 2‰ of the cross-sectional area of the round billet can make the molten steel flow out at a moderate speed, form a stable and reasonable flow field distribution in the mold, ensure the smoothness of the molten steel surface, and lay a foundation for the high-quality forming of the round billet. The ratio of the total opening area is proportional to the cross-sectional area of the cast billet, which helps to achieve the uniformity of the flow rate during the pouring of round billets of different sizes and ensure the stability of the flow field and temperature field.

[0034] Optionally, the included angle between the two side walls of the water outlet hole 2 in the width direction and the cross-section of the nozzle body 1 is θ. The calculation formula for the included angle θ is:

[0035] In the formula, k and c are empirical coefficients, h is the depth of the nozzle inserted into the molten steel, and D is the diameter of the round billet.

[0036] Specifically, k and c in the formula are empirical coefficients, usually taking k = 16 and c = 4. This formula and coefficients are applicable to the super-large cross-section round billet with a diameter above φ1000mm. h represents the depth of the nozzle inserted into the molten steel, and this parameter directly affects the initial pressure and flow path when the molten steel flows out. The deeper the insertion depth, the greater the static pressure when the molten steel flows out. It is necessary to optimize the molten steel outflow direction by adjusting the inclination angle to avoid excessive impact on the bottom of the mold; D is the diameter of the round billet, which reflects the specification size of the billet. Round billets with different diameters correspond to different mold sizes and internal spaces, and different molten steel flow fields are required to ensure the solidification quality. By taking the ratio of h to D as one of the variables, the relationship between the nozzle insertion depth and the round billet specification can be established to ensure that the calculated inclination angle adapts to different working conditions. The empirical coefficients k and c are quantitative corrections to the above theoretical relationship, and they comprehensively consider complex factors such as molten steel temperature, steel grade characteristics, and mold vibration frequency that are difficult to accurately calculate theoretically. Among them, the cross-section is the section perpendicular to the axis of the nozzle body 1.

[0037] Optionally, the wall thickness of the nozzle body 1 does not exceed 20mm.

[0038] Specifically, the wall thickness of the nozzle can be designed to be 20mm, which is less than the wall thickness of 25 - 30mm of the traditional continuous casting submerged nozzle. This design can further reduce the material usage and manufacturing cost, while meeting the requirements of single-use.

[0039] Optionally, the material of the nozzle body 1 is alumina.

[0040] Specifically, for the vertical semi-continuous casting technology of super-large cross-section round billets with a diameter above φ1300mm, the maximum service time of the nozzle is very short, not exceeding 10 hours, and it cannot be reused. Therefore, the submerged nozzle for the super-large cross-section vertical semi-continuous casting round billet is composed of a single low-cost material, specifically alumina, and there is no need to compound refractory materials with higher heat resistance grades and high costs.

[0041] Optionally, it further includes a connecting section 3. The connecting section 3 is provided with a circulation hole. The two ends of the connecting section 3 are respectively connected to one end of the nozzle body 1 far from the water outlet hole 2 and the outlet seat brick of the continuous casting tundish.

[0042] Specifically, the overall structure of the submerged nozzle is divided into the upper inlet connecting section 3 and the nozzle body 1. The upper inlet connecting section 3 is connected to the outlet seat brick of the tundish, and its structural form is the same as that of the traditional continuous casting submerged nozzle. During pouring, the molten steel in the upper tundish flows into the nozzle body 1 through the inlet connecting section 3.

[0043] Furthermore, the connection relationship between the connecting section 3 and the nozzle body 1 is not limited. For example, two separate parts can be connected together by means such as clamping and welding. Preferably, the connecting section 3 and the nozzle body 1 are integrally formed.

[0044] The submerged nozzle for the super-large cross-section vertical semi-continuous casting round billet of the present invention has overall technical characteristics different from the submerged nozzle structure adopted in traditional continuous casting technology, and can meet the special process technical requirements of the vertical semi-continuous casting technology for super-large cross-section round billets with a diameter of more than φ1300mm. For example, taking the φ1600mm super-large cross-section round billet as an example, a submerged nozzle with a five-side-hole structure is adopted. The transverse length of the water outlet hole 2 is 50mm, the axial height is 15mm, and the length-width ratio is 3.33. The total opening area of the five side holes is about 3509mm2, accounting for 1.75‰ of the cross-sectional area of the billet. The insertion depth of the submerged nozzle is 100mm, and the upward angle θ of the side holes is 5°. Please combine with Figure 6 , the molten steel is jet-guided from the five water outlet holes 2 to the liquid surface, and then combined with Figure 7 , it can be clearly seen from the velocity contour map at the meniscus in the figure that there are no obvious local concentration areas in the flow velocities at the meniscus and the billet shell, and the velocity distribution is relatively dispersed and reasonable; in addition, the dispersed jet will also make the temperature distribution in the mold more uniform.

[0045] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. An immersed nozzle for super-large cross-section vertical semi-continuous casting round billet, characterized in that, It includes a nozzle body (1); the nozzle body (1) has a tubular structure, and one end is a closed end; a plurality of water outlet holes (2) are formed in the circumferential side wall of the closed end of the nozzle body (1), and the plurality of water outlet holes (2) are symmetrically distributed with the pipe axis as the center; the length of the water outlet hole (2) in the axial direction of the nozzle body (1) is less than the length in the circumferential direction of the nozzle body (1); from the inside to the outside of the nozzle body (1), the two side walls of the water outlet hole (2) in the width direction gradually incline away from the closed end.

2. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, characterized in that, The aspect ratio of the length to the width of the water outlet hole (2) is 3:1 to 4:

1.

3. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, wherein, The water outlet hole (2) is rectangular or oval.

4. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, characterized in that, The number of the water outlet holes (2) is 5.

5. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to any one of claims 1, characterized in that The included angle between the two side walls of the water outlet hole (2) in the width direction and the cross section of the nozzle body (1) is θ; the calculation formula of the included angle θ is: In the formula, k and c are empirical coefficients, h is the depth of the nozzle inserted into the molten steel, and D is the diameter of the round billet.

6. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, characterized in that, The total area of the plurality of water outlet holes (2) is not greater than 2‰ of the cross-sectional area of the round billet.

7. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, characterized in that, The wall thickness of the nozzle body (1) does not exceed 20 mm.

8. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 1, characterized in that The material of the nozzle body (1) is alumina.

9. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to any one of claims 1-8, characterized in that, It further includes a connecting section (3); the connecting section (3) is provided with a circulation hole; the two ends of the connecting section (3) are respectively connected to the end of the nozzle body (1) far from the water outlet hole (2) and the outlet seat brick of the continuous casting tundish.

10. The submerged nozzle for super-large cross-section vertical semi-continuous casting round billet according to claim 9, characterized in that, The connecting section (3) and the nozzle body (1) are integrally formed.

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