JP2987296B2 - Immersion tube for RH vacuum degassing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dip tube for RH vacuum degassing equipment.

[0002]

2. Description of the Related Art An RH type vacuum degassing apparatus, that is, two immersion pipes for ascending and descending are provided in a degassing tank, and these immersion pipes are immersed in molten steel in a ladle to evacuate the tank. Injecting gas such as argon or nitrogen from one immersion pipe (rising pipe) causes molten steel to flow into the tank, scatter and degas, and the degassed molten steel is supplied to the other immersion pipe (downcoming pipe). ) And return to the ladle. This is a degassing facility that degass by continuing this.

[0003] A dip tube used in such a degassing apparatus is a horizontal brick (hereinafter referred to as a "brick") having a plurality of circumferential sections divided on the inner surface of a cylindrical steel seal fitting having a large number of studs or the like implanted on its outer surface. , Which is referred to as an inner winding brick) in a plurality of stages to form an inner cylinder (an integral inner winding brick is also used), between the inner winding brick and the sealing hardware, and the outer periphery of the sealing hardware. Is formed by applying an irregular-shaped refractory such as a castable refractory to an outer cylinder, and arranging a plurality of gas injection pipes penetrating the inner and outer cylinders.

By the way, when the above-mentioned immersion pipe is immersed in molten steel in a ladle and subjected to vacuum degassing, wear due to the high temperature of the molten steel and the shock turbulence accompanying the reflux of the molten steel, or repeated wear. Rapid heating due to use, wear due to rapid cooling, spalling occurs and is promoted and worn. In particular, irregular-shaped refractories forming the outer cylinder are generally repaired frequently by means such as spray repair using irregular-shaped refractories of a sprayed material because of poor corrosion resistance and large damage compared to refractory bricks. It will be. In addition, slag, ingots and the like stick to the outer peripheral surface. Since the spray repair and the removal of the adhered slag are performed at high temperatures, measures to reduce spray repair and prevent slag from sticking to slag are required. As a measure to reduce and prevent sticking, there is an immersion pipe in which an externally wound brick is provided around the outer periphery of the immersion pipe.

In the meantime, when the externally wound brick is provided around the outer peripheral portion of the immersion pipe, a plurality of annular gas injection pipes for circulating molten steel are provided on the outer peripheral surface of the seal fitting. Therefore, when the sealing hardware and the outer brick are brought into close contact, it is necessary to form a groove on the inner peripheral surface side of the outer brick in accordance with the piping state of the gas injection pipe, which makes the production of the immersion pipe extremely complicated. Become. In addition, since the externally-wound brick is usually provided with a brick of a laterally-closed shape in which the circumferential direction is divided into a plurality of pieces, it is simply adhered with mortar or the like and provided around the outer peripheral portion of the dip tube. If you only have it, it will fall outside during operation and it will fall off.

In view of the foregoing, the present invention has been made to provide an immersion pipe for an RH vacuum degassing facility which facilitates the production of the immersion pipe and prevents the externally wound brick from falling down or falling off during operation. It was made for the purpose.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention relates to a dip tube for vacuum degassing immersed in molten steel. A locking member provided on a flange hangs an upper end of an externally wound brick which is circumferentially arranged and arranged in a vertical direction, and a lower end thereof is locked by a locking member provided on a sealing hardware. The material of the locking member is metal or ceramic.

[0008]

In the present invention, since the upper end and the lower end of the outer brick placed and arranged around the outer periphery of the dip tube are suspended and locked by the locking member, the outer brick is separated from the outer peripheral surface of the seal fitting. Externally placed bricks can be placed around and arranged at the position, and a groove is formed on the inner peripheral surface side of the outer brick in accordance with the piping state of multiple gas injection pipes that are annularly piped to the outer peripheral surface of the seal hardware The elimination of the necessity of the above-described process facilitates the production of the dip tube. In addition, it is possible to prevent the externally wound brick from falling or falling off during operation. For this reason, bricks made of, for example, MgO-C or the like, which have higher corrosion resistance and are less likely to adhere to the refractory than amorphous refractories, are disposed on the outer peripheral surface side to improve the corrosion resistance in a stable state, reduce spraying repair, prevent slime adhesion, etc. Therefore, the life of the immersion tube can be greatly extended.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to an embodiment shown in the drawings.

FIG. 1 shows a longitudinal section of a dip tube according to the present invention, and FIG. 2 shows a horizontal section corresponding to the line A--A in FIG. At the inner periphery of a cylindrical steel seal fitting 2 in which a number of studs 1 and the like are implanted on the outer surface, an inner winding brick 3 composed of a horizontal pressing brick divided in a plurality of circumferential directions is joined in a plurality of stages. An inner tube 6 is formed by lining them together, and an irregular-shaped refractory 4 such as a castable refractory and an outer-wound brick 10 are constructed between the inner brick 3 and the seal hardware 2 and on the outer periphery of the seal hardware 2. The outer cylinder 7 has a configuration in which a plurality of gas injection pipes 5 penetrating the inner and outer cylinders 6 and 7 are arranged and integrated.

In the illustrated embodiment, the inner brick 3 is vertically stacked in two layers, and a U-shaped hook portion is formed on the back (outer peripheral surface) of the lower inner brick 3. The entire body is hung by a support fitting 2a protruding inward at a position slightly higher than the lower end of the refractory, and an irregular refractory 4 is disposed below the lower end thereof.

On the outer peripheral side of the conventional dip tube, an externally wound brick 10 vertically integrated via an irregular refractory 4 is provided around an outer side of the outer peripheral portion away from the seal fitting 2.

When the outer brick 10 is degassed by immersing the immersion pipe in molten steel, the damage on the outer peripheral surface side immersed in the molten steel due to the high temperature and slag of the molten steel proceeds rapidly. It is provided in order to reduce repair work that must be performed frequently by means such as spray repair, or to prevent sticking of slag, ingots, etc., to the entire outside of the seal fitting 2. If it is installed and arranged, the strength of the externally wound brick 10 can be increased and the life can be prolonged, but a plurality of gas injection pipes 5 for circulating molten steel are annularly provided on the outer peripheral surface of the seal fitting 2. When the outer brick 10 is brought into close contact with the outer brick 10, it is necessary to form a groove on the inner peripheral surface side of the outer brick 10 in accordance with the piping state of the gas injection pipe 5, and the production of the dip tube becomes extremely complicated. To the minimum necessary As shown in the enlarged view of FIG. 3, the circumferential direction is divided into a plurality of parts according to the size of the immersion pipe at a position away from the seal fitting 2 via the irregular refractory 4 outside the seal fitting 2. The bricks of the horizontal approaching shape are joined by one step, and are provided from immediately below the flange 8 to the lower position.

A hole 10a of a predetermined size is formed at a predetermined position on the outer peripheral surface and the lower end surface of the outer winding brick 10 at a predetermined position on the outer peripheral surface and the lower end surface thereof in order to fix the outer winding brick 10 at a position away from the seal hardware 2. ing.

The material of the outer brick 10 has a large amount of C, a small coefficient of thermal expansion, a high corrosion resistance, a high spalling resistance and the like in order to prevent sticking and improve the durability. It is preferable that the material has characteristics, and MgO-C can be used as a material having these quality characteristics.

The locking member 9 is provided to fix the outer winding brick 10 at a position separated from the sealing hardware 2.
For example, it is made of ordinary steel such as a rolled steel material for general structure, or special steel such as stainless steel, and one example thereof has a projection 9a suspended from the outside of the long side of an L-shaped cross section as shown in FIG. A concave portion 10a having a shape corresponding to the protrusion 9a is provided on the outer periphery and / or lower end surface of the upper end portion of the outer brick 10 and the protrusion 9a is inserted into the concave portion 10a. And / or can be fixed to the outer periphery of the seal fitting 2 by appropriate means such as welding or screwing.

When the externally wound brick 10 is to be installed and arranged, a positioning metal fitting 2b such as a bolt or an iron plate is welded to a predetermined position on the outer peripheral surface of the seal fitting 2 and then provided. After the side is inserted and fixed in a concave portion 10 a formed in a predetermined position of the outer winding brick 10, the irregular refractory 4 is filled between the seal fitting 2 and the outer winding brick 10.

Therefore, in the above configuration, in place of the conventional amorphous refractory 4 in the circumferential direction of the outer peripheral surface of the immersion pipe, the sealing metal 2 is used.
Since the externally wound bricks 10 are arranged and arranged at a position away from the base and fixed by the locking members 9, not only the production of the dip tube is facilitated, but also the collapsed and fall-off during operation is prevented, and the molten steel is retained. Damage due to high temperature and slag can be significantly reduced, and repair work such as spray repair can be reduced, as well as sticking of slag and slag can be prevented.

The locking member 9 is provided so as to protrude from the outside of the metal seal 2, and is made of a ceramic material such as zirconia, alumina, sialon or the like instead of steel. Oxidization and melting due to the high temperature of molten steel can be prevented, and the service life can be greatly extended.

In the embodiment shown in the figure, the inner bricks 3 are stacked in two layers, and a U-shaped hooking portion is formed on the back of the lower inner brick 3 and suspended therefrom. Although the case of the dip tube provided with is shown, an inner winding brick 3 in which the vertical direction is integrated or formed in three or more stages is used, the hook portion is formed in an L shape, and the lower inner winding brick is turned downward. To form a truncated cone, or to eliminate the irregular refractory 4 below the inner brick 3. Furthermore, although only the protrusion of the locking member is cylindrical, it is needless to say that the whole may be cylindrical and bent in an L-shape.

[0021]

As described above, according to the present invention, in an immersion pipe for immersing in molten steel and performing vacuum degassing,
Since the outer brick is placed around the seal metal through an irregular refractory and separated from the seal metal, it is placed around the seal metal. Therefore, it is not necessary to form a groove on the inner peripheral surface of the outer brick, so that the production of the dip tube can be facilitated. In addition, when performing degassing treatment by immersing the immersion tube in molten steel by fixing the externally wound brick with the flange and seal metal and the locking member, the refractory brick with higher corrosion resistance than conventional amorphous refractories is in operation The present invention can be applied without falling down or falling off, so that damage on the outer peripheral surface side of the immersion pipe can be greatly reduced, and as a result, repair work such as spray repair can be greatly reduced. Also,
By applying the MgO-C material which does not easily adhere to the outer brick, it is possible to prevent the adherence of the slag during operation, reduce the slag removal work, and thus greatly extend the life of the dip tube. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a dip tube according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is an enlarged longitudinal sectional view of a main part.

FIG. 4 is a perspective view showing an example of a locking member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stud 2 Seal metal 3 Inner winding brick 4 Irregular refractory 5 Gas blowing pipe 6 Inner cylinder 7 Outer cylinder 8 Flange 9 Locking member 10 Outer brick

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C21C 7/10 F27D 1/14

Claims (2)

(57) [Claims] 1. A dip tube for immersing in molten steel and performing vacuum degassing treatment, wherein the dip tube is provided around an outer peripheral portion of the dip tube.
RH vacuum degassing characterized in that an upper end of an externally wound brick vertically integrated is suspended by a locking member provided on a flange, and the lower end is locked by a locking member provided on a seal metal. Immersion tube for equipment. 2. The immersion pipe for RH vacuum degassing equipment according to claim 1, wherein the material of the locking member is metal or ceramic.