Upper-nozzle / upper-plate integrated object

Abstract

Provided is a combination upper nozzle and upper plate capable of preventing alumina in molten steel from adhering to a lower portion of an upper nozzle where the alumina adheres heavily. A combination upper nozzle and upper plate (1) used for a slide gate, the combination upper nozzle and upper plate (1) including gas blowing portions (21 and 22) in two places, in which one gas blowing portion (21) is capable of blowing a gas to at least an upper portion of an upper nozzle (1-1), and the other gas blowing portion (22) is capable of blowing the gas simultaneously to a lower portion of the upper nozzle (1-1) and a sliding surface of an upper plate (1-2).

Description

Technical Field

[0001] The present invention relates to a combination upper nozzle and upper plate used for a slide gate.Background Art

[0002] A slide gate (also referred to as a slide nozzle) is placed in the bottom of a tundish to regulate the flow of molten steel. The slide gate includes an upper nozzle, an upper plate, a lower plate, and a submerged entry nozzle. In a case of continuous casting for a long time, the submerged entry nozzle needs to be frequently replaced during continuous casting. In this case, the upper nozzle and the upper plate are integrated into a combination upper nozzle and upper plate, the lower plate and the submerged entry nozzle are integrated into a combination lower plate and submerged entry nozzle, and it is configured in such a manner that the combination lower plate and submerged entry nozzle is slid relative to the combination upper nozzle and upper plate to control the outflow of molten steel and the submerged entry nozzle can be replaced quickly. Even if continuous casting is not performed for a long time, the upper nozzle and the upper plate are still integrated into the combination upper nozzle and upper plate.

[0003] In the known combination upper nozzle and upper plate, a gas such as an inert gas is blown to the upper nozzle to prevent alumina from adhering to an inner surface of a hole of the upper nozzle. Moreover, the gas such as an inert gas is blown to a sliding surface of the upper plate to prevent entraining air into the molten steel (refer to Patent Literature 1). In order to blow the gas to the upper nozzle and blow the gas to the sliding surface of the upper plate, gas blowing portions are provided in two places to the combination upper nozzle and upper plate. One gas blowing portion blows the gas to the upper nozzle, and the other gas blowing portion blows the gas to the sliding surface of the upper plate.Citation ListPatent Literature

[0004] Patent Literature 1: Description of U.S. Patent No. 5431374Summary of InventionTechnical Problem

[0005] However, the combination upper nozzle and upper plate has the gas blowing portion for blowing the gas to the upper nozzle in only one place, and therefore, has a problem that alumina in molten steel is likely to adhere particularly to a lower portion of the upper nozzle. If the lower portion of the upper nozzle is clogged with alumina, there arise problems that operation needs to be stopped, the tundish needs to be replaced due to the reduced casting cycle time, and the replacement frequency of a refractory such as the submerged entry nozzle increases further.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a combination upper nozzle and upper plate capable of preventing alumina in molten steel from adhering to a lower portion of an upper nozzle where the alumina adheres heavily.Solution to Problem

[0007] In order to solve the above problems, one aspect of the present invention is a combination upper nozzle and upper plate used for a slide gate, the combination upper nozzle and upper plate including gas blowing portions in two places, in which one gas blowing portion is capable of blowing a gas to at least an upper portion of an upper nozzle, and the other gas blowing portion is capable of blowing the gas simultaneously to a lower portion of the upper nozzle and a sliding surface of an upper plate.Advantageous Effects of Invention

[0008] According to the present invention, the other of the gas blowing portions in the two places is capable of blowing the gas simultaneously to the lower portion of the upper nozzle and the sliding surface of the upper plate. Therefore, when a groove in the sliding surface of the upper plate is filled with the gas, the gas is preferentially supplied to the lower portion of the upper nozzle. Since a gas film can be stably formed in the lower portion of the upper nozzle, it is possible to prevent alumina from adhering to the lower portion of the upper nozzle. As a result, the casting cycle time is increased, the replacement of a tundish becomes less frequent, the replacement of a refractory such as a submerged entry nozzle becomes less frequent, and the economic effect is increased.Brief Description of Drawings

[0009] Fig. 1 is a vertical cross-sectional view of a slide gate using a combination upper nozzle and upper plate of one embodiment of the present invention. Fig. 2 is a vertical cross-sectional view of one gas blowing portion of the combination upper nozzle and upper plate of the embodiment. Fig. 3 is a vertical cross-sectional view of the other gas blowing portion of the combination upper nozzle and upper plate of the embodiment. Fig. 4 is a plan view of the combination upper nozzle and upper plate of the embodiment. Description of Embodiment

[0010] A combination upper nozzle and upper plate of an embodiment of the present invention is described in detail hereinafter with reference to the accompanying drawings. However, the combination upper nozzle and upper plate of the present invention can be embodied in various forms, and is not limited to the embodiment described in the present description. The embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by fully disclosing the present description.

[0011] As illustrated in Fig. 1, a combination upper nozzle and upper plate 1 of the embodiment forms a part of a slide gate 3. A tundish 4 holds molten steel. The slide gate 3 controls the outflow of the molten steel from the tundish 4. The slide gate 3 includes the combination upper nozzle and upper plate 1 and a combination lower plate and submerged entry nozzle 2. The combination lower plate and submerged entry nozzle 2 is slid by an unillustrated machine in a horizontal direction relative to the combination upper nozzle and upper plate 1. The flow rate of the molten steel depends on the degree of overlap between a hole 1a of the combination upper nozzle and upper plate 1 and a hole 2a of the combination lower plate and submerged entry nozzle 2.

[0012] The combination upper nozzle and upper plate 1 is inserted into an attachment plate 5 and an opening portion of a bottom wall 6 of the tundish 4. A refractory 7 such as a ramming material surrounds the combination upper nozzle and upper plate 1.

[0013] The combination lower plate and submerged entry nozzle 2 includes a lower plate 2-1 and a submerged entry nozzle 2-2. The lower plate 2-1 and the submerged entry nozzle 2-2 are integrally molded by, for example, CIP molding in such a manner as to enable quick replacement. It is to be noted that the lower plate 2-1 and the submerged entry nozzle 2-2 may be molded separately and integrated with, for example, mortar and an iron shell. Moreover, an unillustrated lower nozzle may be interposed between the lower plate 2-1 and the submerged entry nozzle 2-2.

[0014] As illustrated in Fig. 2, the combination upper nozzle and upper plate 1 includes an upper plate 1-2 and an upper nozzle 1-1 fixed to a recessed portion 28b of the upper plate 1-2. The upper nozzle 1-1 includes an upper porous refractory 11, a middle refractory 12, and a lower porous refractory 13. The upper porous refractory 11 and the lower porous refractory 13 are configured in such a manner as to be permeable to a gas such as argon gas. The porosities of the upper porous refractory 11 and the lower porous refractory 13 are, for example, 20 to 25%, which are greater than the porosity of the middle refractory 12. The materials of these refractories 11, 12, and 13 are not particularly limited. For example, an alumina-based refractory material, a zirconia-based refractory material, and a magnesia-based refractory material can be used.

[0015] The hole 1a of the upper nozzle 1-1 includes a receiving end 1a1 placed on the floor of the tundish 4, and a discharge end 1a2 placed concentrically with the upper plate 1-2. A tubular shoulder portion 14 protruding downward is formed around the discharge end 1a2.

[0016] A ring-shaped groove 15 (hereinafter referred to as the gas pool portion 15) extending in a circumferential direction is formed in an outer surface of the upper porous refractory 11. A vertical groove 16 connected to the gas pool portion 15 is formed in the outer surfaces of the upper porous refractory 11, the middle refractory 12 and the lower porous refractory 13. The vertical groove 16 is coated with a sealing material in such a manner as to be capable of guiding the gas to the gas pool portion 15.

[0017] The upper porous refractory 11, the middle refractory 12, and the lower porous refractory 13 are covered with a tubular wall 17 (hereinafter referred to as the iron shell 17) formed of, for example, a steel material. An upper portion of the iron shell 17 surrounds an upper portion of the upper porous refractory 11, and is hermetically fixed to the upper portion of the upper porous refractory 11 with a heat-resistant sealing material such as mortar. A lower portion of the iron shell 17 surrounds a lower portion of the lower porous refractory 13, and is hermetically fixed to the lower portion of the lower porous refractory 13 with a heat-resistant sealing material such as mortar. Consequently, the gas that is filled in the gas pool portion 15 through the vertical groove 16 can be confined.

[0018] As illustrated in Fig. 4, the combination upper nozzle and upper plate 1 is provided with gas blowing portions 21 and 22 in two places. The gas blowing portions 21 and 22 are connected to an unillustrated gas supply source such as an argon gas cylinder via an unillustrated valve.

[0019] As illustrated in Fig. 2, one gas blowing portion 21 includes a gas blowing pipe 23 fixed to the iron shell 17, and the vertical groove 16. The gas blowing pipe 23 is connected to the vertical groove 16.

[0020] As illustrated in Fig. 3, the other gas blowing portion 22 includes a gas blowing pipe 24 penetrating the iron shell 17, a slit 25 formed in the lower porous refractory 13, and a vertical hole 26 formed in the upper plate 1-2. The gas blowing pipe 24 includes a T-shaped branch portion 24a inside the lower porous refractory 13. The branch portion 24a is housed in a recessed portion 13a of the lower porous refractory 13. The recessed portion 13a is blocked by, for example, mortar. A main pipe 24a1 of the branch portion 24a is connected to the slit 25. A branch pipe 24a2 of the branch portion 24a is connected to the vertical hole 26. The vertical hole 26 is connected to a ring-shaped groove 27 in a sliding surface of the upper plate 1-2.

[0021] As illustrated in Fig. 4, the upper plate 1-2 has a rectangular shape in plan view. As illustrated in Fig. 3, the upper plate 1-2 includes a dense refractory 28 without pores. The refractory 28 includes a hole 28a linked to the hole 1a of the upper nozzle 1-1 in a center thereof. The recessed portion 28b is formed in an upper surface of the refractory 28. The recessed portion 28b has a shape complementary to the tubular shoulder portion 14 of the upper nozzle 1-1. The tubular shoulder portion 14 of the upper nozzle 1-1 is fixed to the recessed portion 28b with, for example, mortar. The above-mentioned ring-shaped groove 27 is formed in a lower surface of the refractory 28. The material of the refractory 28 is not particularly limited. For example, an alumina-based refractory material, a zirconia-based refractory material, and a magnesia-based refractory material can be used.

[0022] The upper surface and a side surface of the refractory 28 are covered with a tubular wall 29 (hereinafter referred to as the iron shell 29) formed of, for example, a steel material. The iron shell 29 is fixed to the refractory 28 with, for example, mortar. An opening portion for receiving the upper nozzle 1-1 is formed in the iron shell 29. A perimeter 29a of the opening portion is bent in such a manner as to fit the iron shell 17 of the upper nozzle 1-1 thereto, and is welded to the iron shell 17 of the upper nozzle 1-1.

[0023] As illustrated in Fig. 2, when the gas whose pressure and flow rate have been adjusted is supplied to the gas blowing portion 21, the gas is filled in the gas pool portion 15 through the gas blowing pipe 23 and the vertical groove 16, and the gas permeates a wall of the upper porous refractory 11 from the gas pool portion 15. Hence, a gas film is formed on an inner surface of the hole 1a of the upper porous refractory 11. The gas film prevents the molten steel from coming into direct contact with the inner surface of the hole 1a of the upper porous refractory 11. Therefore, it is possible to prevent alumina from adhering to the upper porous refractory 11.

[0024] Similarly, as illustrated in Fig. 3, when the gas whose pressure and flow rate have been adjusted by the valve is supplied to the gas blowing portion 22, the gas is filled in the slit 25 through the main pipe 24a1 of the branch portion 24a of the gas blowing pipe 24, and the gas permeates a wall of the lower porous refractory 13 from the slit 25. Hence, a gas film is formed on an inner surface of the hole 1a of the lower porous refractory 13. The gas film prevents the molten steel from coming into direct contact with the inner surface of the hole 1a of the lower porous refractory 13. Therefore, it is possible to prevent alumina from adhering to the lower porous refractory 13.

[0025] At the same time, as illustrated in Fig. 3, the gas passes through the branch pipe 24a2 of the branch portion 24a and the vertical hole 26, and is filled in the groove 27 in the sliding surface of the upper plate 1-2. The gas is filled in the groove 27, and therefore, it is possible to prevent entraining air into the molten steel from the outside through a place between the sliding surface of the upper plate 1-2 and a sliding surface of the lower plate 2-1.

[0026] When the groove 27 in the sliding surface of the upper plate 1-2 is filled with the gas, the gas is preferentially supplied to the lower porous refractory 13 of the upper nozzle 1-1. Hence, a gas film can be stably formed on the inner surface of the hole 1a of the lower porous refractory 13.

[0027] Effects of the combination upper nozzle and upper plate of the embodiment are described below.

[0028] The gas blowing portion 22 includes the branch portion 24a inside the lower porous refractory 13. Therefore, the combination upper nozzle and upper plate 1 can be made compact, and the combination upper nozzle and upper plate 1 can be easily installed in a machine for a slide gate.

[0029] The upper nozzle 1-1 includes the upper porous refractory 11, the middle refractory 12, and the lower porous refractory 13. Therefore, the gas can be supplied efficiently to the upper porous refractory 11 and the lower porous refractory 13. Upon start of casting, a stopper head may be pressed against an upper portion of the upper nozzle 1-1 to prevent the molten steel from flowing. In this case, alumina is likely to adhere to the upper portion of the upper nozzle 1-1. Moreover, during casting, throttling may be performed by displacing the hole of the upper nozzle and upper plate and the hole of the lower plate and submerged entry nozzle from each other. In this case, stagnation occurs, and therefore, alumina is likely to adhere to a lower portion of the upper nozzle 1-1. The adhesion of alumina can be prevented even in such a case by supplying the gas efficiently to the upper porous refractory 11 and the lower porous refractory 13.

[0030] The gas blowing portion 22 is connected to the ring-shaped slit 25 formed in the lower porous refractory 13. Therefore, the gas film can be stably formed on the inner surface of the hole 1a of the lower porous refractory 13.

[0031] It is to be noted that the combination upper nozzle and upper plate of the present invention is not limited to concretization of the above embodiment, and can be concretized in other embodiments without changing the purport of the present invention.

[0032] In the above embodiment, the upper nozzle includes the three-layer porous refractory, but may include a single-layer porous refractory. Moreover, the one gas blowing portion blows the gas to the upper portion of the upper nozzle in the above embodiment, but the one gas blowing portion may blow the gas to the upper portion and a middle portion of the upper nozzle. Furthermore, in the above embodiment, the slit is formed inside the lower porous refractory. However, a gas pool portion may be formed on an outer surface of the lower porous refractory.

[0033] In the above embodiment, the upper nozzle and the upper plate are joined with mortar and the iron shell, but may be integrally molded by, for example, CIP molding.

[0034] The upper plate may incorporate a zirconia insert to prevent abrasion of the refractory.

[0035] The present description is based on Japanese Patent Application No. 2023-106612 filed on June 29, 2023. The entire contents thereof are incorporated herein.Reference Signs List

[0036] 1Combination upper nozzle and upper plate 1-1Upper nozzle 1-2Upper plate 3Slide gate 11Upper porous refractory (upper portion of the upper nozzle) 12Middle refractory 13Lower porous refractory (lower portion of the upper nozzle) 21One gas blowing portion 22The other gas blowing portion 24aBranch portion 25Slit

Examples

Embodiment Construction

[0010]A combination upper nozzle and upper plate of an embodiment of the present invention is described in detail hereinafter with reference to the accompanying drawings. However, the combination upper nozzle and upper plate of the present invention can be embodied in various forms, and is not limited to the embodiment described in the present description. The embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by fully disclosing the present description.

[0011]As illustrated in Fig. 1, a combination upper nozzle and upper plate 1 of the embodiment forms a part of a slide gate 3. A tundish 4 holds molten steel. The slide gate 3 controls the outflow of the molten steel from the tundish 4. The slide gate 3 includes the combination upper nozzle and upper plate 1 and a combination lower plate and submerged entry nozzle 2. The combination lower plate and submerged entry nozzle 2 is slid by an unillustrated machine in a horizonta...

Technical Field

[0001] The present invention relates to a combination upper nozzle and upper plate used for a slide gate.Background Art

[0002] A slide gate (also referred to as a slide nozzle) is placed in the bottom of a tundish to regulate the flow of molten steel. The slide gate includes an upper nozzle, an upper plate, a lower plate, and a submerged entry nozzle. In a case of continuous casting for a long time, the submerged entry nozzle needs to be frequently replaced during continuous casting. In this case, the upper nozzle and the upper plate are integrated into a combination upper nozzle and upper plate, the lower plate and the submerged entry nozzle are integrated into a combination lower plate and submerged entry nozzle, and it is configured in such a manner that the combination lower plate and submerged entry nozzle is slid relative to the combination upper nozzle and upper plate to control the outflow of molten steel and the submerged entry nozzle can be replaced quickly. Even if continuous casting is not performed for a long time, the upper nozzle and the upper plate are still integrated into the combination upper nozzle and upper plate.

[0003] In the known combination upper nozzle and upper plate, a gas such as an inert gas is blown to the upper nozzle to prevent alumina from adhering to an inner surface of a hole of the upper nozzle. Moreover, the gas such as an inert gas is blown to a sliding surface of the upper plate to prevent entraining air into the molten steel (refer to Patent Literature 1). In order to blow the gas to the upper nozzle and blow the gas to the sliding surface of the upper plate, gas blowing portions are provided in two places to the combination upper nozzle and upper plate. One gas blowing portion blows the gas to the upper nozzle, and the other gas blowing portion blows the gas to the sliding surface of the upper plate.Citation ListPatent Literature

[0004] Patent Literature 1: Description of U.S. Patent No. 5431374Summary of InventionTechnical Problem

[0005] However, the combination upper nozzle and upper plate has the gas blowing portion for blowing the gas to the upper nozzle in only one place, and therefore, has a problem that alumina in molten steel is likely to adhere particularly to a lower portion of the upper nozzle. If the lower portion of the upper nozzle is clogged with alumina, there arise problems that operation needs to be stopped, the tundish needs to be replaced due to the reduced casting cycle time, and the replacement frequency of a refractory such as the submerged entry nozzle increases further.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a combination upper nozzle and upper plate capable of preventing alumina in molten steel from adhering to a lower portion of an upper nozzle where the alumina adheres heavily.Solution to Problem

[0007] In order to solve the above problems, one aspect of the present invention is a combination upper nozzle and upper plate used for a slide gate, the combination upper nozzle and upper plate including gas blowing portions in two places, in which one gas blowing portion is capable of blowing a gas to at least an upper portion of an upper nozzle, and the other gas blowing portion is capable of blowing the gas simultaneously to a lower portion of the upper nozzle and a sliding surface of an upper plate.Advantageous Effects of Invention

[0008] According to the present invention, the other of the gas blowing portions in the two places is capable of blowing the gas simultaneously to the lower portion of the upper nozzle and the sliding surface of the upper plate. Therefore, when a groove in the sliding surface of the upper plate is filled with the gas, the gas is preferentially supplied to the lower portion of the upper nozzle. Since a gas film can be stably formed in the lower portion of the upper nozzle, it is possible to prevent alumina from adhering to the lower portion of the upper nozzle. As a result, the casting cycle time is increased, the replacement of a tundish becomes less frequent, the replacement of a refractory such as a submerged entry nozzle becomes less frequent, and the economic effect is increased.Brief Description of Drawings

[0009] Fig. 1 is a vertical cross-sectional view of a slide gate using a combination upper nozzle and upper plate of one embodiment of the present invention. Fig. 2 is a vertical cross-sectional view of one gas blowing portion of the combination upper nozzle and upper plate of the embodiment. Fig. 3 is a vertical cross-sectional view of the other gas blowing portion of the combination upper nozzle and upper plate of the embodiment. Fig. 4 is a plan view of the combination upper nozzle and upper plate of the embodiment. Description of Embodiment

[0010] A combination upper nozzle and upper plate of an embodiment of the present invention is described in detail hereinafter with reference to the accompanying drawings. However, the combination upper nozzle and upper plate of the present invention can be embodied in various forms, and is not limited to the embodiment described in the present description. The embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by fully disclosing the present description.

[0011] As illustrated in Fig. 1, a combination upper nozzle and upper plate 1 of the embodiment forms a part of a slide gate 3. A tundish 4 holds molten steel. The slide gate 3 controls the outflow of the molten steel from the tundish 4. The slide gate 3 includes the combination upper nozzle and upper plate 1 and a combination lower plate and submerged entry nozzle 2. The combination lower plate and submerged entry nozzle 2 is slid by an unillustrated machine in a horizontal direction relative to the combination upper nozzle and upper plate 1. The flow rate of the molten steel depends on the degree of overlap between a hole 1a of the combination upper nozzle and upper plate 1 and a hole 2a of the combination lower plate and submerged entry nozzle 2.

[0012] The combination upper nozzle and upper plate 1 is inserted into an attachment plate 5 and an opening portion of a bottom wall 6 of the tundish 4. A refractory 7 such as a ramming material surrounds the combination upper nozzle and upper plate 1.

[0013] The combination lower plate and submerged entry nozzle 2 includes a lower plate 2-1 and a submerged entry nozzle 2-2. The lower plate 2-1 and the submerged entry nozzle 2-2 are integrally molded by, for example, CIP molding in such a manner as to enable quick replacement. It is to be noted that the lower plate 2-1 and the submerged entry nozzle 2-2 may be molded separately and integrated with, for example, mortar and an iron shell. Moreover, an unillustrated lower nozzle may be interposed between the lower plate 2-1 and the submerged entry nozzle 2-2.

[0014] As illustrated in Fig. 2, the combination upper nozzle and upper plate 1 includes an upper plate 1-2 and an upper nozzle 1-1 fixed to a recessed portion 28b of the upper plate 1-2. The upper nozzle 1-1 includes an upper porous refractory 11, a middle refractory 12, and a lower porous refractory 13. The upper porous refractory 11 and the lower porous refractory 13 are configured in such a manner as to be permeable to a gas such as argon gas. The porosities of the upper porous refractory 11 and the lower porous refractory 13 are, for example, 20 to 25%, which are greater than the porosity of the middle refractory 12. The materials of these refractories 11, 12, and 13 are not particularly limited. For example, an alumina-based refractory material, a zirconia-based refractory material, and a magnesia-based refractory material can be used.

[0015] The hole 1a of the upper nozzle 1-1 includes a receiving end 1a1 placed on the floor of the tundish 4, and a discharge end 1a2 placed concentrically with the upper plate 1-2. A tubular shoulder portion 14 protruding downward is formed around the discharge end 1a2.

[0016] A ring-shaped groove 15 (hereinafter referred to as the gas pool portion 15) extending in a circumferential direction is formed in an outer surface of the upper porous refractory 11. A vertical groove 16 connected to the gas pool portion 15 is formed in the outer surfaces of the upper porous refractory 11, the middle refractory 12 and the lower porous refractory 13. The vertical groove 16 is coated with a sealing material in such a manner as to be capable of guiding the gas to the gas pool portion 15.

[0017] The upper porous refractory 11, the middle refractory 12, and the lower porous refractory 13 are covered with a tubular wall 17 (hereinafter referred to as the iron shell 17) formed of, for example, a steel material. An upper portion of the iron shell 17 surrounds an upper portion of the upper porous refractory 11, and is hermetically fixed to the upper portion of the upper porous refractory 11 with a heat-resistant sealing material such as mortar. A lower portion of the iron shell 17 surrounds a lower portion of the lower porous refractory 13, and is hermetically fixed to the lower portion of the lower porous refractory 13 with a heat-resistant sealing material such as mortar. Consequently, the gas that is filled in the gas pool portion 15 through the vertical groove 16 can be confined.

[0018] As illustrated in Fig. 4, the combination upper nozzle and upper plate 1 is provided with gas blowing portions 21 and 22 in two places. The gas blowing portions 21 and 22 are connected to an unillustrated gas supply source such as an argon gas cylinder via an unillustrated valve.

[0019] As illustrated in Fig. 2, one gas blowing portion 21 includes a gas blowing pipe 23 fixed to the iron shell 17, and the vertical groove 16. The gas blowing pipe 23 is connected to the vertical groove 16.

[0020] As illustrated in Fig. 3, the other gas blowing portion 22 includes a gas blowing pipe 24 penetrating the iron shell 17, a slit 25 formed in the lower porous refractory 13, and a vertical hole 26 formed in the upper plate 1-2. The gas blowing pipe 24 includes a T-shaped branch portion 24a inside the lower porous refractory 13. The branch portion 24a is housed in a recessed portion 13a of the lower porous refractory 13. The recessed portion 13a is blocked by, for example, mortar. A main pipe 24a1 of the branch portion 24a is connected to the slit 25. A branch pipe 24a2 of the branch portion 24a is connected to the vertical hole 26. The vertical hole 26 is connected to a ring-shaped groove 27 in a sliding surface of the upper plate 1-2.

[0021] As illustrated in Fig. 4, the upper plate 1-2 has a rectangular shape in plan view. As illustrated in Fig. 3, the upper plate 1-2 includes a dense refractory 28 without pores. The refractory 28 includes a hole 28a linked to the hole 1a of the upper nozzle 1-1 in a center thereof. The recessed portion 28b is formed in an upper surface of the refractory 28. The recessed portion 28b has a shape complementary to the tubular shoulder portion 14 of the upper nozzle 1-1. The tubular shoulder portion 14 of the upper nozzle 1-1 is fixed to the recessed portion 28b with, for example, mortar. The above-mentioned ring-shaped groove 27 is formed in a lower surface of the refractory 28. The material of the refractory 28 is not particularly limited. For example, an alumina-based refractory material, a zirconia-based refractory material, and a magnesia-based refractory material can be used.

[0022] The upper surface and a side surface of the refractory 28 are covered with a tubular wall 29 (hereinafter referred to as the iron shell 29) formed of, for example, a steel material. The iron shell 29 is fixed to the refractory 28 with, for example, mortar. An opening portion for receiving the upper nozzle 1-1 is formed in the iron shell 29. A perimeter 29a of the opening portion is bent in such a manner as to fit the iron shell 17 of the upper nozzle 1-1 thereto, and is welded to the iron shell 17 of the upper nozzle 1-1.

[0023] As illustrated in Fig. 2, when the gas whose pressure and flow rate have been adjusted is supplied to the gas blowing portion 21, the gas is filled in the gas pool portion 15 through the gas blowing pipe 23 and the vertical groove 16, and the gas permeates a wall of the upper porous refractory 11 from the gas pool portion 15. Hence, a gas film is formed on an inner surface of the hole 1a of the upper porous refractory 11. The gas film prevents the molten steel from coming into direct contact with the inner surface of the hole 1a of the upper porous refractory 11. Therefore, it is possible to prevent alumina from adhering to the upper porous refractory 11.

[0024] Similarly, as illustrated in Fig. 3, when the gas whose pressure and flow rate have been adjusted by the valve is supplied to the gas blowing portion 22, the gas is filled in the slit 25 through the main pipe 24a1 of the branch portion 24a of the gas blowing pipe 24, and the gas permeates a wall of the lower porous refractory 13 from the slit 25. Hence, a gas film is formed on an inner surface of the hole 1a of the lower porous refractory 13. The gas film prevents the molten steel from coming into direct contact with the inner surface of the hole 1a of the lower porous refractory 13. Therefore, it is possible to prevent alumina from adhering to the lower porous refractory 13.

[0025] At the same time, as illustrated in Fig. 3, the gas passes through the branch pipe 24a2 of the branch portion 24a and the vertical hole 26, and is filled in the groove 27 in the sliding surface of the upper plate 1-2. The gas is filled in the groove 27, and therefore, it is possible to prevent entraining air into the molten steel from the outside through a place between the sliding surface of the upper plate 1-2 and a sliding surface of the lower plate 2-1.

[0026] When the groove 27 in the sliding surface of the upper plate 1-2 is filled with the gas, the gas is preferentially supplied to the lower porous refractory 13 of the upper nozzle 1-1. Hence, a gas film can be stably formed on the inner surface of the hole 1a of the lower porous refractory 13.

[0027] Effects of the combination upper nozzle and upper plate of the embodiment are described below.

[0028] The gas blowing portion 22 includes the branch portion 24a inside the lower porous refractory 13. Therefore, the combination upper nozzle and upper plate 1 can be made compact, and the combination upper nozzle and upper plate 1 can be easily installed in a machine for a slide gate.

[0029] The upper nozzle 1-1 includes the upper porous refractory 11, the middle refractory 12, and the lower porous refractory 13. Therefore, the gas can be supplied efficiently to the upper porous refractory 11 and the lower porous refractory 13. Upon start of casting, a stopper head may be pressed against an upper portion of the upper nozzle 1-1 to prevent the molten steel from flowing. In this case, alumina is likely to adhere to the upper portion of the upper nozzle 1-1. Moreover, during casting, throttling may be performed by displacing the hole of the upper nozzle and upper plate and the hole of the lower plate and submerged entry nozzle from each other. In this case, stagnation occurs, and therefore, alumina is likely to adhere to a lower portion of the upper nozzle 1-1. The adhesion of alumina can be prevented even in such a case by supplying the gas efficiently to the upper porous refractory 11 and the lower porous refractory 13.

[0030] The gas blowing portion 22 is connected to the ring-shaped slit 25 formed in the lower porous refractory 13. Therefore, the gas film can be stably formed on the inner surface of the hole 1a of the lower porous refractory 13.

[0031] It is to be noted that the combination upper nozzle and upper plate of the present invention is not limited to concretization of the above embodiment, and can be concretized in other embodiments without changing the purport of the present invention.

[0032] In the above embodiment, the upper nozzle includes the three-layer porous refractory, but may include a single-layer porous refractory. Moreover, the one gas blowing portion blows the gas to the upper portion of the upper nozzle in the above embodiment, but the one gas blowing portion may blow the gas to the upper portion and a middle portion of the upper nozzle. Furthermore, in the above embodiment, the slit is formed inside the lower porous refractory. However, a gas pool portion may be formed on an outer surface of the lower porous refractory.

[0033] In the above embodiment, the upper nozzle and the upper plate are joined with mortar and the iron shell, but may be integrally molded by, for example, CIP molding.

[0034] The upper plate may incorporate a zirconia insert to prevent abrasion of the refractory.

[0035] The present description is based on Japanese Patent Application No. 2023-106612 filed on June 29, 2023. The entire contents thereof are incorporated herein.Reference Signs List

[0036] 1Combination upper nozzle and upper plate 1-1Upper nozzle 1-2Upper plate 3Slide gate 11Upper porous refractory (upper portion of the upper nozzle) 12Middle refractory 13Lower porous refractory (lower portion of the upper nozzle) 21One gas blowing portion 22The other gas blowing portion 24aBranch portion 25Slit

Examples

Embodiment Construction

[0010]A combination upper nozzle and upper plate of an embodiment of the present invention is described in detail hereinafter with reference to the accompanying drawings. However, the combination upper nozzle and upper plate of the present invention can be embodied in various forms, and is not limited to the embodiment described in the present description. The embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by fully disclosing the present description.

[0011]As illustrated in Fig. 1, a combination upper nozzle and upper plate 1 of the embodiment forms a part of a slide gate 3. A tundish 4 holds molten steel. The slide gate 3 controls the outflow of the molten steel from the tundish 4. The slide gate 3 includes the combination upper nozzle and upper plate 1 and a combination lower plate and submerged entry nozzle 2. The combination lower plate and submerged entry nozzle 2 is slid by an unillustrated machine in a horizonta...

Claims

1. A combination upper nozzle and upper plate used for a slide gate, the combination upper nozzle and upper plate comprising gas blowing portions in two places, wherein one gas blowing portion is capable of blowing a gas to at least an upper portion of an upper nozzle, and the other gas blowing portion is capable of blowing the gas simultaneously to a lower portion of the upper nozzle and a sliding surface of an upper plate.

2. The combination upper nozzle and upper plate according to claim 1, wherein the other gas blowing portion includes a branch portion inside the upper nozzle.

3. The combination upper nozzle and upper plate according to claim 1 or 2, wherein the upper nozzle includes an upper porous refractory, a middle refractory, and a lower porous refractory, the one gas blowing portion is capable of blowing the gas to the upper porous refractory, and the other gas blowing portion is capable of blowing the gas to the lower porous refractory.

4. The combination upper nozzle and upper plate according to claim 3, wherein the other gas blowing portion is connected to a ring-shaped slit formed in the lower porous refractory.

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