Plate integrated object on upper nozzle

Abstract

To provide a plate-integrated object on an upper nozzle that can suppress alumina adhesion at the bottom of the upper nozzle where alumina adhesion in molten steel is most prevalent.SOLUTION: A plate-integrated object on an upper nozzle 1 used for a sliding gate has two gas blowing parts 21, 22, where one gas blowing part 21 is capable of blowing gas into at least the upper part of the upper nozzle 1-1, and the other gas inlet 22 is capable of blowing gas into the lower part of the upper nozzle 1-1 and the sliding surface of the upper plate 1-2 at the same time.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an upper nozzle / upper plate assembly used in a sliding gate. [Background technology]

[0002] A sliding gate (also called a sliding nozzle) is placed at the bottom of the tundish to adjust the flow of molten steel. The sliding gate is equipped with an upper nozzle, an upper plate, a lower plate, and an SEN. When casting continuously for a long period of time, it is necessary to frequently replace the SEN during the continuous casting. In that case, the upper nozzle and the upper plate are integrated into an upper nozzle-upper plate, and the lower plate and the SEN are integrated into a lower plate-SEN, and the lower plate-SEN is slid against the upper nozzle-upper plate to control the outflow of molten steel and enable the SEN to be replaced quickly. Even when continuous casting is not performed for a long period of time, the upper nozzle and the upper plate are integrated into an upper nozzle-upper plate.

[0003] In a conventional upper nozzle-upper plate assembly, a gas such as an inert gas is blown into the upper nozzle to prevent alumina from adhering to the inner surface of the hole in the upper nozzle. Also, a gas such as an inert gas is blown into the sliding surface of the upper plate to prevent the molten steel from entraining air (see Patent Document 1). In order to blow gas into the upper nozzle and onto the sliding surface of the upper plate, two gas blowing sections are provided in the upper nozzle-upper plate assembly, one of which blows gas into the upper nozzle and the other gas blowing section blows gas onto the sliding surface of the upper plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 5,431,374 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the upper nozzle-upper plate combination, there is only one gas inlet for injecting gas into the upper nozzle, so there is a problem that alumina in molten steel is likely to adhere to the lower part of the upper nozzle in particular. If alumina becomes clogged at the lower part of the upper nozzle, problems such as the need to suspend operations, the shortening of the casting cycle and the need to replace the tundish, and the need to replace refractories such as the submerged entry nozzle more frequently may occur.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide an upper nozzle upper plate integral body that can suppress alumina deposition in the lower part of the upper nozzle, where alumina deposition in molten steel is greatest. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention is an upper nozzle and upper plate integrated unit used in a sliding gate, which has two gas blowing sections, one of which is capable of blowing gas into at least an upper part of the upper nozzle, and the other gas blowing section is capable of blowing gas into the lower part of the upper nozzle and the sliding surface of the upper plate simultaneously. Effect of the Invention

[0008] According to the present invention, the other of the two gas blowing sections can blow gas simultaneously into the lower part of the upper nozzle and the sliding surface of the upper plate, so that when the groove on the sliding surface of the upper plate is filled with gas, the gas is preferentially supplied to the lower part of the upper nozzle. Since a gas film can be stably formed on the lower part of the upper nozzle, it is possible to suppress the adhesion of alumina to the lower part of the upper nozzle. As a result, the casting cycle is extended, the replacement of the tundish is reduced, and the replacement of refractories such as the submerged entry nozzle is reduced, resulting in an economical effect. [Brief description of the drawings]

[0009] [Figure 1]1 is a vertical cross-sectional view of a sliding gate using an integrated upper nozzle and upper plate according to one embodiment of the present invention. FIG. [Diagram 2] 1 is a vertical cross-sectional view of one gas blowing portion of an upper nozzle and upper plate integral assembly according to the present embodiment. FIG. [Diagram 3] 11 is a vertical cross-sectional view of the other gas blowing portion of the upper nozzle / upper plate integral assembly of the present embodiment. FIG. [Figure 4] FIG. 4 is a plan view of an upper nozzle and upper plate integral assembly according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an upper nozzle and upper plate integrated assembly according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the upper nozzle and upper plate integrated assembly according to the present invention can be embodied in various forms and is not limited to the embodiments described herein. The present embodiment is provided with the intention of enabling those skilled in the art to fully understand the invention by fully disclosing the specification.

[0011] As shown in FIG. 1, the upper nozzle upper plate integral body 1 of this embodiment constitutes a part of the sliding gate 3. The tundish 4 holds molten steel. The sliding gate 3 controls the outflow of molten steel from the tundish 4. The sliding gate 3 includes the upper nozzle upper plate integral body 1 and the lower plate submerged entry nozzle integral body 2. The lower plate submerged entry nozzle integral body 2 slides horizontally relative to the upper nozzle upper plate integral body 1 by a machine (not shown). The flow rate of the molten steel depends on the degree of overlap between the hole 1a of the upper nozzle upper plate integral body 1 and the hole 2a of the lower plate submerged entry nozzle integral body 2.

[0012] The upper nozzle and upper plate integral body 1 is inserted into an opening in a mounting plate 5 and a bottom wall 6 of a tundish 4. The periphery of the upper nozzle and upper plate integral body 1 is surrounded by a refractory material 7 such as a ramming material.

[0013] The lower plate and submerged nozzle assembly 2 comprises a lower plate 2-1 and a submerged nozzle 2-2. The lower plate 2-1 and the submerged nozzle 2-2 are integrally molded by CIP molding or the like so as to enable quick replacement. The lower plate 2-1 and the submerged nozzle 2-2 may be molded separately and then integrated with mortar, iron shell, or the like. A lower nozzle (not shown) may be interposed between the lower plate 2-1 and the submerged nozzle 2-2.

[0014] As shown in FIG. 2, the upper nozzle-upper plate integral assembly 1 includes an upper plate 1-2 and an upper nozzle 1-1 fixed to a recess 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 to be permeable to gases such as argon gas. The porosity of the upper porous refractory 11 and the lower porous refractory 13 is, for example, 20 to 25%, which is larger than the porosity of the middle refractory 12. The material of these refractories 11, 12, and 13 is not particularly limited, and an alumina-based refractory material, a zirconia-based refractory material, a magnesia-based refractory material, or the like can be used.

[0015] The hole 1a of the upper nozzle 1-1 has a receiving end 1a1 disposed on the floor of the tundish 4 and a discharge end 1a2 disposed concentrically with the upper plate 1-2. A cylindrical shoulder 14 protruding downward is formed around the periphery of the discharge end 1a2.

[0016] A ring-shaped groove 15 (hereinafter referred to as a gas pool portion 15) extending in the circumferential direction is formed on the outer surface of the upper porous refractory 11. A vertical groove 16 connected to the gas pool portion 15 is formed on 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 so that gas can be guided 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 cylindrical wall 17 (hereinafter referred to as the iron shell 17) formed of a steel material or the like. The upper part of the iron shell 17 surrounds the upper part of the upper porous refractory 11 and is sealably fixed to the upper part of the upper porous refractory 11 by a heat-resistant sealing material such as mortar. The lower part of the iron shell 17 surrounds the lower part of the lower porous refractory 13 and is sealably fixed to the lower part of the lower porous refractory 13 by a heat-resistant sealing material such as mortar. This allows the gas filling the gas pool section 15 through the vertical grooves 16 to be trapped.

[0018] 4, the upper nozzle and upper plate integral body 1 is provided with two gas blowing parts 21 and 22. The gas blowing parts 21 and 22 are connected to a gas supply source such as an argon gas cylinder (not shown) via a valve (not shown).

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

[0020] As shown in FIG. 3, the other gas blowing section 22 includes a gas blowing pipe 24 penetrating the steel 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 has a T-shaped branching section 24a inside the lower porous refractory 13. The branching section 24a is housed in a recessed section 13a of the lower porous refractory 13. The recessed section 13a is filled with mortar or the like. A main pipe 24a1 of the branching section 24a is connected to the slit 25. A branching pipe 24a2 of the branching section 24a is connected to the vertical hole 26. The vertical hole 26 is connected to a ring-shaped groove 27 in the sliding surface of the upper plate 1-2.

[0021] As shown in FIG. 4, the upper plate 1-2 is rectangular in plan view. As shown in FIG. 3, the upper plate 1-2 includes a dense refractory material 28 having no pores. The refractory material 28 has a hole 28a in the center thereof, which is connected to the hole 1a of the upper nozzle 1-1. A recess 28b is formed on the upper surface of the refractory material 28. The recess 28b has a shape complementary to the cylindrical shoulder portion 14 of the upper nozzle 1-1. The cylindrical shoulder portion 14 of the upper nozzle 1-1 is fixed to the recess 28b by mortar or the like. The above-mentioned ring-shaped groove 27 is formed on the lower surface of the refractory material 28. The material of the refractory material 28 is not particularly limited, and an alumina-based refractory material, a zirconia-based refractory material, a magnesia-based refractory material, or the like can be used.

[0022] The top and sides of the refractory material 28 are covered with a cylindrical wall 29 (hereinafter referred to as the shell 29) made of steel or the like. The shell 29 is fixed to the refractory material 28 with mortar or the like. An opening for receiving the upper nozzle 1-1 is formed in the shell 29. The periphery 29a of the opening is bent so that the shell 17 of the upper nozzle 1-1 can fit therein, and is welded to the shell 17 of the upper nozzle 1-1.

[0023] 2, when gas with adjusted pressure and flow rate is supplied to the gas injecting section 21, the gas passes through the gas injecting pipe 23 and the vertical groove 16 to fill the gas pool section 15, and then the gas penetrates the wall of the upper porous refractory 11. As a result, a gas film is formed on the inner surface of the hole 1a of the upper porous refractory 11. This gas film prevents the molten steel from directly contacting the inner surface of the hole 1a of the upper porous refractory 11, so that adhesion of alumina to the upper porous refractory 11 can be suppressed.

[0024] 3, when gas whose pressure and flow rate are adjusted by a valve is supplied to the gas blowing section 22, the gas passes through the main pipe 24a1 of the branched section 24a of the gas blowing pipe 24, filling the slit 25, and then the gas penetrates the wall of the lower porous refractory 13. As a result, a gas film is formed on the inner surface of the hole 1a of the lower porous refractory 13. This gas film prevents the molten steel from directly contacting the inner surface of the hole 1a of the lower porous refractory 13, so that adhesion of alumina to the lower porous refractory 13 can be suppressed.

[0025] At the same time, as shown in Fig. 3, gas passes through the branch pipe 24a2 of the branch section 24a and the vertical hole 26 to fill the groove 27 on the sliding surface of the upper plate 1-2. Filling the groove 27 with gas makes it possible to prevent the molten steel from drawing in air from the outside through the gap between the sliding surface of the upper plate 1-2 and the sliding surface of the lower plate 2-1.

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

[0027] The effects of the integral upper nozzle and upper plate of this embodiment will be described below.

[0028] Since the gas blowing section 22 has a branch section 24a inside the lower porous refractory material 13, the upper nozzle-upper plate integrated unit 1 can be made compact, and the upper nozzle-upper plate integrated unit 1 can be easily installed on a machine for a sliding gate.

[0029] Since the upper nozzle 1-1 includes the upper porous refractory 11, the middle refractory 12, and the lower porous refractory 13, gas can be efficiently supplied to the upper porous refractory 11 and the lower porous refractory 13. When starting casting, a stopper head may be pressed against the upper part of the upper nozzle 1-1 to prevent the molten steel from flowing. In this case, alumina is likely to adhere to the upper part of the upper nozzle 1-1. Also, during casting, the hole of the upper nozzle upper plate and the hole of the lower plate submerged nozzle may be shifted to perform throttle injection. In this case, stagnation occurs, and alumina is likely to adhere to the lower part of the upper nozzle 1-1. By efficiently supplying gas to the upper porous refractory 11 and the lower porous refractory 13, adhesion of alumina can be suppressed even in such cases.

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

[0031] The upper nozzle and upper plate integral assembly of the present invention is not limited to being embodied in the above-described embodiment, but may be embodied in other embodiments without departing from the spirit and scope of the present invention.

[0032] In the above embodiment, the upper nozzle is made of three layers of porous refractory, but it may be made of a single layer of porous refractory. In the above embodiment, one gas blowing part blows gas into the upper part of the upper nozzle, but it may be made of a single layer of porous refractory. Furthermore, in the above embodiment, a slit is formed inside the lower porous refractory, but a gas pool part may be formed on the outer surface of the lower porous refractory.

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

[0034] The upper plate may incorporate zirconia inserts to prevent refractory wear. [Explanation of symbols]

[0035] 1...Upper nozzle and upper plate integrated 1-1…Upper nozzle 1-2…Upper plate 3. Sliding gate 11...Upper porous refractory (upper part of upper nozzle) 12...Central refractories 13...Lower porous refractory (lower part of upper nozzle) 21...One gas inlet 22...The other gas blowing section 24a…Branch 25…Slit

Claims

1. An upper nozzle and upper plate integral assembly used in a sliding gate, It has two gas inlet ports. One of the gas blowing units is capable of blowing gas into at least an upper portion of the upper nozzle, The other gas blowing section is an upper nozzle and upper plate integral body capable of blowing gas simultaneously into the lower part of the upper nozzle and the sliding surface of the upper plate.

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

3. The upper nozzle includes an upper porous refractory, a middle refractory, and a lower porous refractory, The one gas blowing section is capable of blowing gas into the upper porous refractory material, 3. The upper nozzle and upper plate integral assembly according to claim 1, wherein the other gas blowing portion is capable of blowing gas into the lower porous refractory material.

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

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