Long-life slab tundish upper nozzle and mounting method thereof

Abstract

The invention discloses a long-service-life slab tundish upper nozzle and an installation method thereof. The long-service-life slab tundish upper nozzle comprises an upper nozzle body and a matched seating brick. The upper part of the outer surface of the upper nozzle and the upper part of the central hole of the seating brick are circular truncated cone surfaces which are matched with each other; and the lower part of the outer surface of the upper nozzle and the lower part of the central hole of the seating brick are cylindrical surfaces which are matched with each other. By improving the mounting method of the upper nozzle and the seat brick matched with the upper nozzle, the mounting precision of the seat brick is ensured, and steel seepage between the upper nozzle and the seat brick is avoided, so that the seepage of molten steel between the upper nozzle and the seat brick is controlled, the influence of flushing of the upper nozzle and the steel seepage between the upper nozzle and the seat brick is reduced, and the service life of the upper nozzle and the seat brick is prolonged; long-time and long-casting-time continuous casting of continuous casting is guaranteed, and cost reduction and benefit increase are achieved. The service life of the upper nozzle is prolonged through different choices of materials of different parts of the upper nozzle, and the service life can be further prolonged. By adopting the invention and the method, the service life of the upper nozzle can be prolonged from 12 hours to 16 hours.

Description

Technical Field

[0001] The invention relates to a metallurgical continuous casting tundish, in particular to an upper water inlet of a long-life slab tundish and a mounting method thereof. Background Art

[0002] With global overcapacity and shrinking demand, competition in the steel industry is becoming increasingly fierce. Continuous casting with a long-life and long-casting tundish is an effective measure to reduce costs and increase efficiency in the continuous casting process, and the long-life tundish water inlet is the core technology of the long-life tundish. Therefore, the long-life tundish water inlet technology is a hot spot in the current continuous casting refractory technology.

[0003] There are two main factors that affect the life of the tundish nozzle during the casting process: one is the melting loss of the refractory material of the nozzle itself. Because during the entire casting process, the stopper rod and the bowl mouth of the tundish nozzle will be eroded and washed to a certain extent. When the contact surface between the two is abnormally eroded or cracked, the appropriate molten steel pouring speed cannot be guaranteed, and it cannot continue to be used. Therefore, the quality of the tundish nozzle has an important impact on the service life of the entire tundish. The second is the steel seepage between the nozzle and its matching seat brick. Because in the tundish, the nozzle is protected by the matching nozzle seat brick. The combination of the nozzle and the seat brick is generally designed to be a combination of an upper cone and a lower straight section. As the steel pouring time increases, there will be a problem of molten steel seeping along the gap between the nozzle and the seat brick. In severe cases, the molten steel will flow further to the lower part, to the tundish shell, causing the molten steel in the tundish to leak, which becomes a vicious production and safety accident. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a long-life slab tundish water inlet; the present invention also provides a method for installing the long-life slab tundish water inlet.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: including a water inlet and a matching seat brick; the upper part of the outer surface of the water inlet and the upper part of the center hole of the seat brick are both matching conical surfaces, and the lower part of the outer surface of the water inlet and the lower part of the center hole of the seat brick are both matching cylindrical surfaces.

[0006] Furthermore, the ratio of the height B of the frustum of the upper part of the center hole of the seat brick to the difference A between the maximum diameter and the minimum diameter of the frustum is B / A=10±2.

[0007] Furthermore, the water inlet bowl of the water inlet is made of high-purity corundum raw material, and the particle size ratio of the high-purity corundum raw material is: 3-1mm particle size ratio is 30%-40%, 1-0mm particle size ratio is 40%-50%, 200 mesh particle size ratio is 15%-20%, and the porosity is 15%-25%; the water inlet lining uses high-aluminum raw material, and the particle size ratio of the high-aluminum raw material is: 3-1mm particle size ratio is 20%-30%, 1-0mm particle size ratio is 30%-40%, 200 mesh particle size ratio is 30%-40%, porosity ≤4%, and the carbon content is guaranteed to be 18%-23%; the water inlet quick-change surface uses high-purity plate-shaped corundum, a high-temperature sintering agent is added to the raw material, and anti-oxidation treatment is performed before use.

[0008] In order to solve the above technical problems, the technical solution adopted by the method of the present invention includes the following steps: 1) installing the upper water inlet on the tundish according to the process requirements; 2) Insert the center hole of the seat brick into the water inlet from top to bottom from the upper part of the water inlet until the seat brick can no longer move downward; 3) Spread dry material or ramming material between the seat brick and the bottom of the tundish, and tamp it down; 4) Lift the seat brick upwards until it is completely out of the water inlet; 5) Apply fire clay on the outer surface of the upper water inlet; 6) Insert the seat brick into the water inlet from the upper part again until the seat brick can no longer move downward; 7) Apply the coating material on the top of the base brick and tamp it down.

[0009] Furthermore, in the step 2), after the seat brick is inserted, measure the distance H1 between the top of the upper water inlet and the upper surface of the seat brick; in the step 6), measure the distance H2 between the top of the upper water inlet and the upper surface of the seat brick; if H2-H1≤15mm, it is considered qualified, otherwise repeat steps 2) to 6) until H2-H1≤15mm.

[0010] Furthermore, in step 5), 3 to 5 mm of fire clay is applied on the outer surface of the upper water inlet.

[0011] Furthermore, in step 7), 30 to 40 mm of coating material is spread on the top of the seat brick and compacted.

[0012] The beneficial effects produced by the above-mentioned technical scheme are as follows: the present invention and method improve the installation method of the water inlet and its matching seat bricks to ensure the installation accuracy of the seat bricks and avoid the occurrence of steel seepage between the water inlet and the seat bricks, thereby controlling the infiltration of molten steel between the water inlet and the seat bricks, reducing the impact of water inlet scouring and steel seepage between the water inlet and the seat bricks, and improving its service life, ensuring continuous casting for a long time and long pouring times, and achieving cost reduction and efficiency improvement. The present invention improves the service life of the water inlet by selecting different materials for different parts of the water inlet, and can further improve the service life. By adopting the invention and method, the service life of the water inlet can be increased from 12 hours to 16 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0014] Figure 1 It is a structural schematic diagram of the seat brick of the present invention; Figure 2 It is a schematic diagram of the structure after the water inlet of the present invention is installed; Figure 3 It is a schematic diagram of the structure of the pre-installation of the water inlet of the present invention; Figure 4 It is a structural schematic diagram of the water inlet of the present invention.

[0015] In the figure: 1-upper water inlet, 2-seat brick, 3-permanent layer, 4-dry material layer at the bottom of the package, 5-intermediate package bottom, 6-fire clay, 7-gap, 8-upper water inlet bowl, 9-upper water inlet body, 10-upper water inlet lining, 11-upper water inlet quick-change surface. DETAILED DESCRIPTION

[0016] During the continuous casting process of the tundish, the upper water inlet and the stopper head work together to control the steel flow. Therefore, the upper water inlet has good resistance to erosion by molten steel, especially the inner hole part, which must be resistant to both erosion by molten steel and chemical corrosion. It must also have good air permeability to prevent the water inlet from being blocked and flocculating.

[0017] Figure 1 , 2As shown in Figures 3 and 4, the long-life slab tundish water inlet includes a water inlet 1 and a matching seat brick 2. The water inlet 1 includes a water inlet bowl 8, a water inlet body 9, a water inlet lining 10 and a water inlet quick-change surface 11; the water inlet body 9 is cylindrical, and the upper part of the outer surface is slightly inclined inward to facilitate the insertion of the seat brick 2; the water inlet lining 10 is arranged on the inner surface of the water inlet body 9, and the height of the water inlet lining 10 is lower than the height of the water inlet body 9; the water inlet bowl 8 is arranged on the top of the water inlet lining 10 and the water inlet body 9, and the water inlet quick-change surface 11 is arranged on the bottom of the water inlet lining 10 and the water inlet body 9. The seat brick 2 is provided with a center hole, and is sleeved and covered on the outside of the water inlet 1 through the center hole to protect the water inlet 1. The upper part of the outer surface of the water inlet 1 and the upper part of the center hole of the base brick 2 are both matched frustum surfaces, and the lower part of the outer surface of the water inlet 1 and the lower part of the center hole of the base brick 2 are both matched cylindrical surfaces. The ratio of the frustum height B of the upper part of the center hole of the base brick 2 to the difference A between the maximum diameter and the minimum diameter of the frustum is 10, that is, the maximum diameter of the bottom of the frustum - the minimum diameter of the top = A, B / A = 10 ± 2, preferably B / A = 10; similarly, the ratio of the frustum height of the upper part of the outer surface of the water inlet 1 to the difference between the maximum diameter and the minimum diameter of the frustum is also 10 ± 2.

[0018] Therefore, the upper nozzle of the long-life slab tundish is made of the following materials: the upper nozzle bowl 8 is made of high-purity corundum raw material, and the particle size ratio of the high-purity corundum raw material is: 3-1mm particle size ratio is 30%-40%, 1-0mm particle size ratio is 40%-50%, 200 mesh particle size ratio is 15%-20%, and the porosity is 15%-25%; a sintering agent and a binder are added, preferably metal aluminum powder is used as a sintering agent, and phenolic resin is used as a binder. The upper nozzle lining 10 is made of high-aluminum raw material, and the particle size ratio of the high-aluminum raw material is: 3-1mm particle size ratio is 20%-30%, 1-0mm particle size ratio is 30%-40%, 200 mesh particle size ratio is 30%-40%, porosity ≤4%, and the carbon content is guaranteed to be 18%-23%; a binder is added, and phenolic resin is preferably used as a binder. The upper water inlet quick-change surface 11 uses high-purity plate-shaped corundum, and the Al2O3 content of the high-purity plate-shaped corundum is ≥99.5%; corundum is used as the raw material, and the particle size ratio is 3-1mm accounting for 15-30%, 1-0mm accounting for 25-45%, 200 mesh accounting for 15-30%, and the remainder is high-temperature sintering agent, resin and anti-oxidation treatment raw materials; the high-temperature sintering agent is preferably metal aluminum powder, and the amount of metal aluminum powder added is 0.3-1.5wt% of the weight of the upper water inlet quick-change surface 11; the corundum is subjected to anti-oxidation treatment before use, and the anti-oxidation treatment is preferably performed by adding 0.5-2% of silicon carbide by weight of the upper water inlet quick-change surface 11.

[0019] Figure 1 , 2As shown in FIG. 3 , the method for installing the upper nozzle of the long-life slab tundish comprises the following steps: 1) The water inlet 1 is installed on the tundish according to the process requirements; 2) Slowly insert the cylindrical surface of the center hole of the seat brick 2 downward from the upper part of the water inlet 1 until the round table surface at the upper part of the center hole of the seat brick 2 contacts the round table surface at the upper part of the outer surface of the water inlet 1 and cannot move downward any further; measure the distance H1 between the top of the water inlet 1 and the upper surface of the seat brick 2; 3) Spread dry material or ramming material between the seat brick 2 and the middle ladle bottom 5, and tamp it to form a ladle bottom dry material layer 4 or a ramming material layer; 4) Lift the seat brick 2 upward until it is completely separated from the water inlet 1; 5) Apply fire mud 6 on the outer surface of the upper water inlet 1, the thickness of the fire mud 6 is 3-5 mm, and the temperature of the fire mud is not less than 5°C; 6) Rotate the seat brick 2 and slowly insert it into the water inlet 1 from the upper part of the water inlet 1 again, and knock the seat brick 2 with a rubber hammer until the bottom of the seat brick 2 contacts the bottom dry material layer 4 or the ramming material layer and cannot move downward any further; 7) Measure the distance H2 between the top of the water inlet 1 and the upper surface of the base brick 2 again. If H2-H1≤15mm, it is considered qualified. Otherwise, repeat steps 2) to 7) until H2-H1≤15mm; 8) Spread a coating material with a thickness of 30-40 mm on the top of the seat brick 2 and then tamp it down. The mixing standard of the coating material is that it can be dispersed when it is kneaded into a ball by hand and then loosened.

[0020] Figure 2 As shown, after installation, the structure of the tundish and the upper water inlet is as follows: the upper water inlet 1 is installed at the water inlet position of the tundish, the seat brick 2 covers the outer side of the upper water inlet 1 inside the tundish, the seat brick 2 and the upper water inlet 1 are filled with fire mud 6, the space between the seat brick 2 and the bottom 5 of the tundish is filled with a bottom dry material layer 4 or a ramming material layer, and there is a gap 7 between the outer surface of the seat brick 2 and the permanent layer 3 of the tundish. Example

[0021] The upper nozzle bowl 8 is made of high-purity corundum raw material. By adjusting the particle ratio, the 3-1mm particle size ratio is 35%, the 1-0mm particle size ratio is 47%, the 200 mesh particle size ratio is 18%, and the porosity is 15%, ensuring that the bowl has good air permeability during use. The material with high porosity can not only ensure the good thermal shock resistance of the product, but also ensure that argon can pass through the nozzle bowl well during use to form a protective gas film to avoid contact between molten steel and the nozzle bowl, while preventing floccules and bowl scouring, and extending the service life of the nozzle.

[0022] The upper nozzle lining 10 is made of high-aluminum material. By adjusting the particle size ratio of the raw materials, the 3-1mm particle size ratio is 20%, the 1-0mm particle size ratio is 40%, and the 200 mesh particle size ratio is 40%, the porosity is 3%, and the carbon content is 18%, which can ensure the thermal shock resistance of the product and effectively improve the resistance of the inner wall of the nozzle to molten steel erosion and chemical corrosion.

[0023] The upper water inlet quick-change surface 11 uses high-purity plate-shaped corundum with an Al2O3 content of 99.5%, adds high-temperature sintering agent, 0.8% metal aluminum powder, and is anti-oxidation treated before use, and 1.0% silicon carbide to improve the high-temperature wear resistance and oxidation resistance of the quick-change surface, thereby increasing the service life of the water inlet.

[0024] Perform an appearance inspection on the tundish water inlet 1, the seat brick 2, etc. used for installation, requiring them to be free of damage, cracks, and moisture. Measure the dimensions of the water inlet 1 and the seat brick 2 to ensure they meet the process requirements. After installation using the above method, the service life of the water inlet described in this embodiment is 14 hours. Example

[0025] The upper nozzle bowl 8 is made of high-purity corundum raw material. By adjusting the particle ratio, the 3-1mm particle size ratio is 30%, the 1-0mm particle size ratio is 50%, the 200 mesh particle size ratio is 20%, and the porosity is 25%, ensuring that the bowl has good air permeability during use. The material with high porosity can not only ensure the good thermal shock resistance of the product, but also ensure that argon can pass through the nozzle bowl well during use to form a protective gas film to avoid contact between molten steel and the nozzle bowl, while preventing floccules and bowl scouring, and extending the service life of the nozzle.

[0026] The upper nozzle lining 10 is made of high-aluminum material. By adjusting the particle size ratio of the raw materials, the 3-1mm particle size ratio is 27%, the 1-0mm particle size ratio is 38%, and the 200 mesh particle size ratio is 35%, so that the porosity is ≤4% and the carbon content is 23%, which can ensure the thermal shock resistance of the product and effectively improve the resistance of the inner wall of the nozzle to molten steel erosion and chemical corrosion.

[0027] The upper water inlet quick-change surface 11 uses high-purity plate-shaped corundum with an Al2O3 content of 99.5%, adds high-temperature sintering agent 0.7% metal aluminum powder, and undergoes anti-oxidation treatment and 1.5% silicon carbide before use to improve the high-temperature wear resistance and oxidation resistance of the quick-change surface, thereby increasing the service life of the water inlet.

[0028] After installation using the above method, the service life of the water inlet described in this embodiment is 16 hours.

Claims

1. A long-life slab tundish water inlet, characterized by: It comprises an upper water inlet (1) and a matching base brick (2); the upper part of the outer surface of the upper water inlet (1) and the upper part of the center hole of the base brick (2) are both matched round table surfaces, and the lower part of the outer surface of the upper water inlet (1) and the lower part of the center hole of the base brick (2) are both matched cylindrical surfaces.

2. The long-life slab tundish water inlet according to claim 1 is characterized by: The ratio of the height B of the frustum of the upper part of the center hole of the seat brick (2) to the difference A between the maximum diameter and the minimum diameter of the frustum is B / A=10±2.

3. A long-life slab tundish water inlet according to claim 1 or 2, characterized in that: The water inlet bowl portion (8) of the water inlet (1) is made of high-purity corundum raw material, and the particle size ratio of the high-purity corundum raw material is: 3-1 mm particle size ratio is 30%-40%, 1-0 mm particle size ratio is 40%-50%, 200 mesh particle size ratio is 15%-20%, and the porosity is 15%-25%; the water inlet lining (10) is made of high-aluminum raw material, and the particle size ratio of the high-aluminum raw material is: 3-1 mm particle size ratio is 20%-30%, 1-0 mm particle size ratio is 30%-40%, 200 mesh particle size ratio is 30%-40%, the porosity is ≤4%, and the carbon content is guaranteed to be 18%-23%; the water inlet quick-change surface (11) is made of high-purity plate-shaped corundum, a high-temperature sintering agent is added to the raw material, and anti-oxidation treatment is performed before use.

4. The method for installing the upper nozzle of the long-life slab tundish according to claim 1, 2 or 3, characterized in that: The method comprises the following steps: 1) installing the water inlet (1) on the tundish according to the process requirements; 2) Insert the center hole of the base brick (2) into the water inlet (1) from the top to the bottom, until the base brick (2) can no longer move downward; 3) Spread dry material or ramming material between the seat brick (2) and the bottom of the tundish, and tamp it down; 4) Lift the base brick (2) upward until it is completely separated from the water inlet (1); 5) Apply fire clay to the outer surface of the water inlet (1); 6) Insert the seat brick (2) again from the upper part of the water inlet (1) downwards into the water inlet (1) until the seat brick (2) can no longer move downwards; 7) Spread the coating material on the top of the base brick (2) and tamp it down.

5. The method for installing a long-life slab tundish water inlet according to claim 4, characterized in that: In the step 2), after the base brick (2) is inserted, the distance H1 between the top of the water inlet (1) and the upper surface of the base brick (2) is measured; in the step 6), the distance H2 between the top of the water inlet (1) and the upper surface of the base brick (2) is measured; if H2-H1≤15mm, it is considered qualified, otherwise, repeat steps 2) to 6) until H2-H1≤15mm.

6. The method for installing a long-life slab tundish water inlet according to claim 4, characterized in that: In the step 5, 3 to 5 mm of fire clay is applied to the outer surface of the water inlet (1).

7. The method for installing a long-life slab tundish water inlet according to claim 4, 5 or 6, characterized in that: In the step 7, 30 to 40 mm of coating material is spread on the top of the seat brick (2) and then compacted.

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