JP3002871U - Immersion tube for vacuum degassing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] In the immersion pipe for vacuum degassing equipment, by setting the length of the seal metal object to be short, cracks and peeling due to expansion and deformation of the lower part of the refractory structure can be prevented. It is possible to suppress the invasion of the outside air, to prevent the invasion of the outside air due to the opening of joints and the like without extending the joints by forming the inner-wall brick in a single step and to extend the life of the immersion pipe. In an immersion pipe for performing a vacuum degassing treatment by immersing it in molten steel, a plurality of inwardly wound bricks, which are integrally formed in the axial direction of the soaked pipe, are arranged in a cylindrical shape, and an outer peripheral surface upper part of the inwardly wound brick is disposed. The vacuum degassing equipment, characterized in that the length of the seal metal object that is hung around the outer periphery of the inner brick is set to be approximately half the axial length of the immersion pipe from the upper end flange. It may be provided in a dip pipe for use, an L-shaped steel rod for holding an irregular shaped refractory is protrudingly provided at a lower end of the sealing metal article, and an irregular refractory layer is provided on a lower end surface of an inward-wrapping brick. An inert gas blowing mechanism may be provided in the.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dip tube for RH vacuum degassing equipment.

[0002]

[Prior art]

 In the RH vacuum degassing equipment, the degassing tank is provided with two dipping pipes for raising and lowering, and the dipping pipe is immersed in molten steel in the ladle to evacuate the tank, and one dipping pipe The molten steel flows into the tank by being blown with a gas such as argon or nitrogen and is scattered to degas, and the degassed molten steel is discharged from the other immersion pipe (downcomer pipe). Return to the ladle. It is a degassing facility that degasses molten steel by continuing this process.

The immersion pipe used in such a degassing facility has a horizontal brick (in which a plurality of studs and the like are planted on the outer surface thereof) formed on the inner surface of a cylindrical steel seal metal piece in the circumferential direction. (Inner winding bricks) will be lined by joining them in multiple stages to form an inner cylinder. Between the inner winding brick and the seal metal object and around the seal metal, castable refractory or other irregular fire An object is constructed into an outer cylinder, and a plurality of gas injection pipes penetrating the inner cylinder and the outer cylinder are arranged and integrated.

By the way, when the above immersion pipe is immersed in the molten steel in the ladle and subjected to vacuum degassing treatment, the high temperature of the molten steel and the wear due to the shocking turbulence accompanying the circulation of the molten steel, or repeated Rapid heating due to use and spalling due to rapid cooling occur and are promoted and worn. In particular, the inner-wall bricks that form the inner cylinder are stacked in multiple layers (usually three layers) in the vertical direction, so the horizontal direction of the inner-wall bricks that are laminated by the molten steel recirculation or the blowing of an inert gas The joints are damaged in advance, and the inner bricks easily fall off.

As a solution to such a problem, there is one disclosed in Japanese Utility Model Publication No. 5-7230. The immersion pipe described in this publication (1 in the figure of the publication) is a vertical direction in which the inner cylinder refractory (inner brick) crosses the axis of the cylinder, and there is no joint that divides the inner cylinder refractory. It is designed to be integrated. Further, as an embodiment in the above publication, FIG. 1 shows an inner cylinder refractory material supported by a brim at the lower end of a metal cylindrical body (sealing metal object).

[0006]

[Problems to be solved by the device]

 However, in the structure shown in FIG. 1 of the above publication, a hook having an L-shaped cross section is formed in the lower part of the inner brick, and the hook is hooked to the support receiving metal fitting projecting on the inner peripheral surface side of the lower end of the metal seal. Since the inner brick is supported at the bottom, the support bracket is also integrally expanded as the lower end of the metal seal expands. In addition, since the inner brick is exposed on the lower end surface of the dip pipe, the inner brick and the amorphous refractory on the outer periphery are separated. In particular, in the case of immersion pipes that have been treated for a long time such that the treatment ratio of ultra-low carbon steel has increased in recent years and the treatment time has exceeded 30 minutes, the lower part that is immersed in the molten steel repeats due to the high temperature of the molten steel. During use, the lower part of the seal metal piece opens and deforms like a flare skirt, and the supporting brackets integrally welded to the seal metal piece also open. In addition, the expansion of inner bricks and amorphous refractories does not become larger than the expansion of seal metal. Therefore, if the lower part of the metal seal opens and deforms like a flare skirt, it deforms the irregular refractory that is installed on the outer periphery from the inside and causes cracks, or the inner brick and the irregular refractory are cracked. There is a problem in that the gaps are separated and a gap is created, and molten steel enters during dipping, which melts the metal seals, studs, or support brackets, and eventually the inner bricks fall off during use.

In view of this, the present invention provides a dip tube for a vacuum degassing equipment, which can prevent the lower part of the sealing metal piece from expanding and deforming toward the end and preventing the inner winding brick from falling off. It was made for the purpose.

[0008]

[Means for Solving the Problems]

 The inventors of the present invention developed the immersion pipe structure of the present invention as a result of various studies and experiments in order to solve the above-mentioned problems, and the technical configuration of the present invention is to perform vacuum degassing treatment by immersing in molten steel. In the dipping pipe for performing the above-mentioned dipping pipe, a plurality of inner winding bricks which are integrally formed in the axial direction of the dipping pipe are arranged in a cylindrical shape, and are suspended above the outer peripheral surface of the inner winding brick. The immersion pipe for a vacuum degassing facility is characterized in that the length of the seal metal fitting that surrounds the upper end flange is approximately half the axial length of the immersion pipe. An L-shaped steel rod for holding an irregular shaped refractory may be protrudingly provided on the lower end of the metal object, and an irregular refractory layer may be provided on the lower end surface of the inwardly wound brick, and an inert gas blowing mechanism is provided on the outer periphery of the upper part of the sealed metallic object. May be.

According to the dip tube of the present invention having the above-mentioned technical structure, the length of the sealing metal object can be shortened by suspending the inner winding brick from the upper part, and the lower part can be suspended. To prevent the occurrence of cracks on the outer peripheral irregular-shaped refractory caused by the expanded deformation of the inner wall, separation of inner bricks and irregular refractory, or separation of seal metal and irregular refractory from the outside air. Intrusion bricks can be suppressed, and the inner bricks have a single-stage structure with no horizontal joints, so that the horizontal joints are not damaged, and therefore the life of the immersion pipe can be greatly extended.

[0010]

[Action]

 In the present invention, it is not necessary to make the axial dimension (vertical direction) of the sealing metal article longer than necessary, and it is possible to prevent the lower portion from expanding and deforming in a divergent manner by making it shorter than before. it can. As a result, cracks are generated in the irregular refractory that is installed on the outer periphery, or the invisible bricks and the irregular refractory on the outer periphery are separated and a gap is created to prevent molten steel from entering during immersion. In addition, since the inner bricks are constructed in a single stage and suspended at the upper part, even if the lower part of the sealing metal object is expanded and deformed by the high temperature held by the molten steel, it expands. The support receiving portion is not expanded and deformed, and it is possible to reliably suspend and prevent the inner brick from falling off.

[0011]

【Example】

 Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings.

FIG. 1 shows a vertical cross section of an example of a dip tube according to the present invention, and FIG. 2 shows a horizontal cross section corresponding to the line AA in FIG. Joining an inner winding brick 3 composed of laterally squeezing bricks divided into a plurality of circumferential directions to the inner circumference of a cylindrical steel sealing metal fitting 2 fixed to a flange 8 and having a large number of studs 1 and the like planted on the outer surface. The inner cylinder 6 is lined by means of, and between the inner brick 3 and the seal metal 2 and on the outer periphery of the seal metal 2, an amorphous refractory 4 such as castable refractory 4 is applied to form an outer cylinder 7. In addition, a plurality of gas injection pipes 5 penetrating the outer cylinders 6 and 7 are arranged to be integrated.

[0013] The inner brick 3 is composed of horizontal bricks that are divided into a plurality of pieces in the circumferential direction and lengthened in the vertical direction, and are formed in a cylindrical shape with one step. A hooking portion having a V-shape is formed, and the whole structure is suspended by a support receiving metal fitting 2a provided on the inner peripheral side of the metal seal 2 at a position slightly lower than the lower surface of the flange 8.

The inner brick 3 is configured in a single step with a length dimension from the lower end face of the dipping pipe to the upper position of the dip, and even when immersed in the molten steel, the receiving metal fitting 2a is not immersed and the molten steel is held. A hook with a U-shaped cross-section is formed on the back of the flange, which is not directly exposed to high temperatures, at a position slightly lower than the bottom of the flange, and the entire upper part is suspended by the support bracket 2a protruding from the inner circumference of the metal seal 2. To have. The bottom surface of the inner brick 3 is surrounded by the irregular refractory 4 so that the inner brick 3 and the irregular refractory 4 applied to the outer periphery of the inner brick 3 do not separate from each other to form a gap. Then, as shown by 4a, the inner peripheral surface of the molten steel flow hole is provided.

The sealing metal 2 has a role of blocking the invasion of air from the outside and a role of supporting the entire inner-wrapped brick 3, and since the inner-wrapped brick 3 is laminated in a plurality of stages in the conventional dipping pipe. In addition, it was necessary to set the dimension long enough to support the whole with the innermost brick at the bottom, but if it is set long, the expansion of the lower part will increase due to the high temperature of the molten steel and the expansion will increase. By repeatedly expanding and deforming while expanding and contracting toward the end, cracks may be generated in the irregular refractory 4 on the outer periphery, or the inner brick 3 and the irregular refractory 4 may be separated to form a gap. As a result, molten steel may invade, or a gap may be created between the seal metal 2 and the irregular-shaped refractory 4 installed on the inner and outer peripheries, which may lead to invasion of outside air. Also block the outside air from entering below The length is set to the minimum required to achieve the above, and the dimension is set to a short length up to the position near the position of the inert gas inlet 9.

[0016] Accordingly, since the portion for suspending the inner-wall brick 3 in a single stage is provided in the upper portion by the above-mentioned configuration, it is possible to prevent the support receiving metal fitting 2a from integrally expanding, and the seal metal fitting. 2 can be set to be short, and it is possible to prevent the diameter dimension from expanding and deforming toward the end.

At the lower portion of the sealing metal piece 2, round steels 10 of the same number as the number of the circumferential direction of the inner brick 3 are divided into a plurality of pieces are provided at equal intervals by means of welding or the like, and the tip side is formed into an L shape. When the inner brick is bent and brought into contact with the lower end surface of the inner brick 3, it is possible to prevent the inner brick from falling off when a crack occurs, and it is possible to significantly extend the useful life.

Furthermore, if the studs 1 and the like are planted in the round steel 10, it is not necessary to use the long stud 1 downward, and the irregular fireproof structure installed on the outer circumference of the inner brick 3 The object 4 can be supported, and the service life can be further extended.

In the illustrated embodiment, the immersion pipe is shown in which a hook portion having a U-shaped cross section is formed on the back surface of the inner brick 3, but the hook portion may be formed in a U-shaped cross section, or It can be pierced in a concave shape and can be suspended by a support rod. In addition, the hook portions can be provided in two steps, one above the other, for hanging. Further, it goes without saying that the seal metal 2 may be constrained by being banded on the outer periphery of the lower end with a round steel or the like.

FIG. 3 is a vertical cross-sectional view similar to FIG. 1 showing an example in which a porous refractory material 10 having an inert gas injection space 11 is buried in the outer periphery of the upper portion of the metal seal 2, and the same reference numerals as those in FIG. The same member is shown. As shown in the example of Fig. 3, by injecting an inert gas, even if cracks or peeling occur in the refractory structure part, contact between the molten steel to be treated and the atmosphere can be prevented, and the molten steel It is possible to prevent nitrogen absorption and the like.

[0021]

[Effect of device]

 According to the dipping pipe of the present invention, the length of the shell metal object can be set short by suspending the inner winding brick at the upper part, and the lower part can be expanded and deformed in a divergent shape toward the outer periphery. Prevents cracking of irregular refractories, separation of inner bricks from irregular refractories, or separation of seal metal from irregular refractories, and configures the inner brick of the immersion pipe in a single stage. Since the immersion pipe is immersed in the molten steel for degassing, the molten pipe is horizontally suspended due to the shocking recirculation of the molten steel or turbulent flow due to the blowing of an inert gas. It is possible to prevent the joint part from being damaged in advance, suppress the infiltration of molten steel and the outside air, and further prolong the life of the immersion pipe.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a dip tube according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a vertical sectional view showing another example of the present invention.

[Explanation of symbols]

 1 Stud 2 Seal metal 3 Inner brick 4 Unshaped refractory 5 Gas injection pipe 6 Inner cylinder 7 Outer cylinder 8 Flange 9 Inert gas injection port 10 Porous refractory 11 Gas injection void

Claims (4)

[Scope of utility model registration request] 1. A dip tube for immersing in molten steel for vacuum degassing, wherein a plurality of inner winding bricks, which are integrated in the axial direction of the dipping tube, are arranged in a cylindrical shape, and the outer circumference of the inner winding brick is arranged. The vacuum desorbing device is characterized in that the length of the seal metal object that is hung above the surface and provided around the outside of the inner brick is approximately half the axial length of the dipping pipe from the upper end flange. Immersion pipe for gas equipment. 2. The vacuum degassing equipment according to claim 1, wherein an L-shaped round bar is provided so as to project from a lower end surface of the metal seal, and the L-shaped round bar holds an irregular-shaped refractory. Dip tube. 3. The immersion pipe for vacuum degassing equipment according to claim 1 or 2, wherein an amorphous refractory layer is provided in a lower portion of the inner brick. 4. The immersion pipe for vacuum degassing equipment according to claim 1, wherein a porous refractory having an empty space for injecting an inert gas is embedded in an outer periphery of an upper portion of the metal seal.