JP2981402B2 - Repair method of reflux pipe of 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 method for repairing a reflux pipe in a vacuum degassing facility, and more particularly to a method of disassembling and repairing an inner brick at an opening at the bottom of a tank to greatly extend the service life. Repair method. In the present invention, the “reflux pipe” refers to a reflux pipe in a DH type vacuum degassing facility and an RH type vacuum degassing facility.

[0002]

2. Description of the Related Art Vacuum degassing equipment, especially RH type vacuum degassing equipment, is mainly composed of a lower tank having a plurality of (usually two) immersion tubes at the lower end thereof, and each part is provided with a respective one. An appropriate material is selected according to the amount of wear and lining is applied.

[0003] The service life of the lining in each of these parts is generally the part where the flow velocity of the molten steel reaches the maximum and the explosion of bubbles and the like also occurs. Often governed by the condition of the part. And since this part is located between the inside of the tank and the immersion pipe, it cannot be easily replaced like the immersion pipe. Therefore, various measures have been conventionally taken for the brickwork and the repair method. ing.

For brickwork, for example, a tank bottom structure of a vacuum processing apparatus has been proposed (see Japanese Utility Model Publication No. 63-11166). The brick structure at the bottom of the tank (hereinafter referred to as “conventional brick structure at the bottom of the tank”) will be described with reference to FIG. 6, which is described as “Brick structure at the bottom of a vacuum processing apparatus having a dip tube. In the above, the brickwork around the tank bottom opening 21 connected to the dip tube is replaced with a small horizontal brick 22.
a, 22b is provided with a plurality of windings, and a filling layer of an irregular refractory 24 is provided between the outer circumference of the plurality of windings and the bottom brick 23, wherein the tank bottom of the vacuum processing apparatus is provided. Structure ”.

[0005] The method of repairing the opening of the reflux pipe is as follows.
For example, a method of repairing a reflux pipe of a vacuum degassing apparatus has been proposed (see Japanese Patent Application Laid-Open No. Sho 60-215712). This repair method (hereinafter referred to as "conventional repair method") will be described with reference to FIG.
Are placed concentrically, the refractory sleeve 31 is inserted into the reflux pipe A by attaching the immersion pipe B to the reflux pipe A, and then the refractory sleeve 31 is inserted between the reflux pipe wear site and the refractory sleeve 31. A method for repairing a reflux pipe of a vacuum degassing apparatus characterized by filling an irregular-shaped refractory 32 ”. FIG.
Reference numeral 33 denotes a press-fit pipe, and reference numeral 34 denotes a flange.

[0006]

However, as is well known, the opening of the reflux pipe in the lower tank of the RH type vacuum degassing equipment is immersed in molten steel in a ladle with a dip tube attached to the lower part thereof to vacuum degassing. When gas treatment is performed, the high temperature of the molten steel and the turbulent flow caused by the reflux of the molten steel cause wear,
Alternatively, rapid heating / quenching due to repeated use generates and promotes spoiling and causes damage.

[0007] In the above-described conventional brickwork structure at the bottom of the tank, when the immersion pipe is immersed in molten steel in a ladle and vacuum degassing is performed, the steel shell on the outer periphery of the tank bottom expands due to the high temperature of the molten steel. Then, the horizontal joints of the inner layer imminent bricks formed by stacking multiple stages by the deformation of the bottom of the can body tank are opened,
The part is prematurely damaged at an accelerated rate.

[0008] In the case of an irregular refractory filler layer provided between the outer layer brick and the brick, the filler layer is provided with a width of about 20 mm at a position about 300 to 400 mm away from the periphery of the opening. However, the expansion of the bricks and the inner and outer layers of the bricks cannot be sufficiently absorbed. For this reason, cracks mainly occur in the uppermost inner layer horizontal brick, and these cracks are rapidly developed due to the difference in specific gravity from the molten steel and the flow of the molten steel that rises while turbulent, and are not blocked by side wall bricks etc. Damage progresses at an accelerated rate due to the separation and floating of the uppermost inner layer horizontal brick on the bottom center side.

On the other hand, in the above-mentioned conventional repair method, the degree of damage to the opening of the reflux pipe is not always uniform, and irregularities are generated on the opening surface due to local damage to the lining brick, adhesion of the metal, etc., or the wall side. The center of the tank bottom is more severely damaged than that of. Therefore, when the refractory sleeve is fitted on the inner hole of the immersion pipe and placed concentrically, the refractory sleeve is fitted.
Not only may not be able to insert the refractory sleeve, or the irregular refractory filled between the damaged part of the reflux pipe and the refractory sleeve may not have a uniform repair thickness. In general, since it is formed of a thin refractory brick having a thickness of about 10 to 65 mm, the number of times of use is small, and frequent repairs are required.

[0010] Further, each part of the lower tank is lined by selecting an appropriate material in accordance with the amount of wear, but generally, the opening of the reflux pipe is damaged more quickly than the side wall. . Therefore, in order to greatly extend the service life as compared with the prior art, it is necessary to establish a repair method capable of inserting a thick-faced sleeve brick into the opening and repairing it easily. Have been.

The present inventors have conducted various studies and experiments in order to solve the above-mentioned problems in the conventional brick structure at the bottom of the tank and the repair method, and have succeeded in developing the repair method of the present invention. Therefore, an object of the present invention is to provide a repair method that not only can extend the life of the most easily damaged reflux pipe opening, but also can easily and easily repair the damaged part. To provide.

[0012]

Means for Solving the Problems The repair method according to the present invention is directed to a method for repairing a reflux pipe in a vacuum degassing facility, wherein a lowermost inner winding brick constituting the reflux pipe and an upper layer thereof are formed into a plurality of layers. Disassemble the innermost inner-brick of the formed inner- brick, at the dismantling location, the lowermost sleeve brick,
40 to 60 mm smaller than the outer diameter of the innermost brick
A recirculation of vacuum degassing equipment characterized by inserting a sleeve brick having an outer diameter and having a large wall thickness made of an upper sleeve brick , and filling an irregular refractory into the back of the sleeve brick. Pipe repair method. "As the gist (technical configuration), thereby achieving the object of the present invention described above.

That is, according to the present invention, by adopting such a technical structure, it is possible to insert and repair a sleeve brick having a large wall thickness, and if necessary, to replace a lower-layer lining brick with a new one. The refractory to be filled on the back side can be made uniform in thickness, so that the most susceptible damage to the prematurely damaged part of the reflux pipe opening can be extended with a small number of repairs This has the effect of extending the life of the entire lower tank significantly.

The reflux pipe for the conventional RH vacuum degassing equipment is as follows:
For example, made of magnesia chromium, high alumina, etc.
Brick of specified shape divided into a plurality of pieces in the circumferential direction according to the size of the reflux pipe for RH type vacuum degassing equipment, in a horizontal or vertical shape with a predetermined inner diameter and thickness It is formed as a one-layer structure in total, or as a two-layer structure in which an outer brick is disposed on the upper periphery. However, in such a conventional RH type reflux pipe for vacuum degassing equipment, cracks occur during repeated use of rapid heating and rapid cooling.
Joint breakage or the like occurs, and the steel is rapidly damaged by the flow of molten steel circulating while turbulent.

Here, a method of repairing a reflux pipe according to the present invention will be described in detail with reference to FIGS. FIG. 1 shows the structure of a reflux tube suitable for carrying out the repair method of the present invention, and FIG. 2 shows the structure of the periphery of the reflux tube. FIGS. 3 and 4 are a longitudinal sectional view and a transverse sectional view, respectively, showing an example of a suitable sleeve brick used in the repair method of the present invention, and FIG. 5 illustrates an example of the repair method of the present invention. FIG.

As shown in FIG. 2, a circulation pipe A suitable for carrying out the repairing method of the present invention comprises, as shown in FIG. 2, (1) a circular or vertical brick having a predetermined shape divided into a plurality in the circumferential direction. (2) Medium-winding brick 2 in which a plurality of similarly-applied horizontal bricks, which are also divided in the circumferential direction, are arranged in a ring, and (3) Paving bricks 4. Externally-wound brick 3 whose outer shape is divided into a plurality in the same circumferential direction and whose shape is determined so that the outer shape becomes an octagonal shape in order to improve the arrangement.
And is formed as a three-layer structure. In addition,
In addition to the above, the shape of the outer brick 3 can be selected from an irregular quadrangle, a circle, and a petal shape as shown in part W in FIG.

The reflux tube A will be further described. As shown in FIG. 1, the reflux tube A is composed of a first-layer (opening side) inner-layer brick 1b in which the upper portion of the reflux tube A is formed in a plurality of layers. A lowermost inner winding brick 1 a is provided to support the inner winding brick 2. The lowermost inner winding brick 1a has a one-layer structure, and the lower back side thereof is formed so as to be inclined downward in a narrow shape in accordance with the shape of the flange 5 (see FIG. 5). The lowermost inner winding brick 1a is provided with a flange 5 (see FIG. 5).
Can be selected according to the shape of the section.

On the other hand, the first-layer inner-brick 1b is formed so as to allow the insertion of the thick-walled sleeve brick 6 (see FIGS. 3 and 4: plan view of FIG. 3). The wall thickness is set to 120 mm or more, preferably 150 mm or more. (Note that “first-layer inner-brick” refers to the opening
Seen from the side, it means “the innermost inner brick”. )

The above-mentioned sleeve brick 6 has a predetermined inner diameter and a predetermined height. That is, the inner winding brick 1 of the reflux pipe A
The outer diameter of the sleeve brick 6 is smaller than the inner diameter of the flange 5 (see FIG. 5) so that the sleeve brick 6 can be inserted from below after dismantling a and 1b. ,
30 to 50 higher than the height dimension of the lowermost inner winding brick 1a of the reflux pipe A
mm. As shown in FIGS. 3 and 4, the sleeve brick 6 is divided into a plurality of circumferentially divided lowermost bricks 6a and an outer diameter of the sleeve brick 6 in the first layer of the reflux tube A. Than the outer diameter of the wound brick 1b (see FIG. 1)
Of 40 to 60 m small fence set upper and divided into a plurality circumferentially Sri - it is constituted by stacking a plurality of stages and a blanking bricks 6b.

As shown in FIG. 3, through holes 6c for connecting the press-fitting pipes 8 (see FIG. 5) are formed in predetermined positions of the upper sleeve brick 6b. Is configured as Further, as shown in FIG. 4, an expansion absorbing material 7 made of a ceramic sheet or the like is dispersed in a vertical joint portion of the upper sleeve brick 6b divided into a plurality of pieces in the circumferential direction of the reflux pipe A, as shown in FIG. It is interposed in several places.

According to the present invention, cracks, joint breaks, etc. occur in the inner winding brick 1 (see FIG. 2) forming the reflux pipe A,
The present invention relates to a method for repairing the reflux pipe A when the thickness of the inner brick 1 is reduced due to damage caused by the flow of molten steel circulating while being turbulent. Specifically, the present invention dismantles the lowermost inner-layer brick 1a shown in FIG. 1 and the first-layer inner-layer brick 1b in which the upper layer is formed in a plurality of layers, and subsequently, shown in FIG. 3 and FIG. The sleeve bricks 6a, 6b are inserted, and then, as shown in FIG.
6b is filled with an irregular refractory 9 via a press-fitting pipe 8 to repair the reflux pipe A.

The method for repairing the reflux pipe A according to the present invention will be described in more detail. First, the inner brick 1 (1a, 1a,
After dismantling 1b), as shown in FIG. 5, a sleeve brick 6 is placed concentrically on a dip tube (not shown), and
By attaching the above-mentioned immersion pipe to the reflux pipe A through the above, the sleeve brick 6 is placed in the reflux pipe A in which the inner brick 1 is dismantled.
Insert When the sleeve brick 6 is inserted into the reflux pipe A, the sleeve brick 6 can be placed on a vertically movable base and inserted. Next, a press-fit pipe 8 is connected to a through hole 6c (see FIG. 3) provided at a predetermined position of the sleeve brick 6, and an irregular refractory 9 is formed on the back of the sleeve brick 6 through the press-fit pipe 8. To repair the reflux pipe A.

According to the method of repairing a reflux pipe according to the present invention,
As described in detail above, the three-layer structure of the reflux tube A (see FIGS. 1 and 2) not only enables the inner winding brick 1 to be dismantled even when hot, but also has a thick wall. The sleeve brick 6 having a large dimension can be inserted, and even if the middle brick 2 in the second layer is damaged when the inner brick 1 is disassembled, the outer brick is placed in the third layer. The presence of 3 makes it possible to secure the strength of the structure. Further, the expansion of the sleeve brick 6 can be absorbed by interposing the expansion absorbing material 7 (see FIG. 4) in the vertical joint of the sleeve brick 6, and the deformation of the bottom of the can body tank can be caused. The occurrence of cracks, joint breaks, and the like can be suppressed.

Furthermore, the lowermost inner winding brick 1a (see FIG. 1) of the reflux pipe A adheres to the brick for the immersion pipe and peels off when the immersion pipe is removed, or the material applied to the upper inner winding brick (1b) is different. If the damage is locally precedent due to the difference, the lowermost inner winding brick 1
a can be partially dismantled, and only the lowermost inner winding brick 1a is newly reloaded to partially repair it.

[0025]

Next, the present invention will be described in more detail with reference to an embodiment of a method for repairing a reflux pipe of a vacuum degassing facility according to the present invention. However, the present invention is not limited to this embodiment. Absent.

In this embodiment, the reflux pipe shown in FIG.
A reflux tube A having a layer structure is applied to a 250 T / ch. RH type vacuum degassing system, and the reflux tube 6 is used by using a sleeve brick 6 (6a, 6b) shown in FIGS. A was repaired. First, after the immersion pipe was removed from the reflux pipe A, the lowermost inner-layer brick 1a and the first-layer inner-layer brick 1b having a plurality of upper layers were dismantled using a breaker.

Next, an upper sleeve brick 6b (thickness: 120 mm) whose outer diameter is reduced by 60 mm from the inner diameter of the first-layer inner-brick 1b (see FIG. 1), (See FIG. 5) 10 mm smaller than the inner diameter of the lowermost sleeve brick 6a whose height is set to be 50 mm lower than the lowermost inner winding brick 1a of the reflux tube A, and stacked with the predetermined inner diameter and height. A sleeve brick 6 (see FIG. 3) having the same dimensions as the integral structure before the repair was placed on the dip tube concentrically.

Subsequently, the dip tube on which the above-mentioned sleeve brick 6 was mounted was attached to the circulation tube A, and the sleeve brick 6 was inserted into the circulation tube A in which the inner brick 1 was disassembled in this way. Thereafter, a press-fit pipe 8 (see FIG. 5) is connected to a through hole 6c (see FIG. 3) provided at a predetermined position of the sleeve brick 6, and a press-fit pipe 8 is inserted into a gap formed on the back of the sleeve brick 6. Was filled with irregular-shaped refractory 9 (see FIG. 5) and repaired.

According to the repairing method of this embodiment, only the effect that the number of repairs can be reduced to one half or less as compared with the conventional repairing method using a thin brick having a small thickness is produced. In addition, there is an effect that the trouble at the time of inserting the sleeve brick, which is caused because the degree of damage of the reflux pipe A is not uniform, is eliminated. As a result, the repair time is not prolonged, and the repair of the reflux tube A and the replacement of the immersion tube can be performed simultaneously in accordance with the damage condition of the immersion tube.

[0030]

According to the present invention, in the case where cracks or joint breaks are generated in the inner winding brick forming the circulation pipe during operation or the inner winding brick is damaged due to the flow of molten steel circulating while turbulent, Unlike the conventional repair method (the method described in Japanese Patent Application Laid-Open No. 60-215712), it is not possible to insert a sleeve brick or to cause a situation where repair must be performed frequently, Disassembling the damaged inner winding brick has the effect of inserting a thicker brick with a thicker wall, and has the effect of being able to be repaired in a planned manner. As a result, the number of repairs can be greatly reduced, Further, there is a remarkable effect that the repair time of the reflux pipe and the replacement time of the immersion pipe coincide with each other so that they can be performed at the same time.

Further, the absorption of the expansion stress of the brick or the deformation stress of the can body does not become insufficient as in the conventional brick structure at the bottom of the tank (the structure described in Japanese Utility Model Publication No. 63-11166). Even if a large sleeve brick with a large thickness is inserted, cracks and breaks can be suppressed.
By extending the life of the reflux pipe opening which is most susceptible to damage, there is an effect that the life of the entire lower tank can be greatly extended.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a reflux tube suitable for carrying out the repair method of the present invention.

FIG. 2 is a plan view showing a structure around a reflux pipe in FIG. 1;

FIG. 3 is a longitudinal sectional view showing an example of a suitable sleeve brick used in the repair method of the present invention.

FIG. 4 is a plan view of the sleeve brick of FIG. 3;

FIG. 5 is a diagram for explaining an example of a repair method according to the present invention.

FIG. 6 is a view showing a conventional brick structure at the bottom of a tank.

FIG. 7 is a view for explaining a conventional repair method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner winding brick 1a Lowermost inner winding brick 1b 1st layer inner winding brick 2 Middle winding brick 3 Outer winding brick 4 Paving brick 5 Flange 6 Sleeving brick 6a Bottom sleeving brick 6b Upper sleeving brick 6c Penetration Hole 7 Expansion absorber 8 Press-fit pipe 9 Irregular refractory 21 Tank bottom opening 22a, 22b Side brick 23 Bottom brick 24 Irregular refractory 31 Refractory sleeve 32 Irregular refractory 33 Press-fit pipe 34 Flange A Reflux tube B Immersion tube

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Yamamoto 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Honko Pipe Co., Ltd. (72) Inventor Masaaki Nishi 1-2-1-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Hiroshi Mitani 1-1-2, Marunouchi, Chiyoda-ku, Tokyo, Japan In-tube (72) Inventor Kazuhiko Araki 1-1-2, Marunouchi, Chiyoda-ku, Tokyo, Japan (56) References JP-A-2-179817 (JP, A) JP-A-4-88116 (JP, A) JP-A-5-195045 (JP, A) JP-A-63-93818 (JP, A A) Jiko 3-7384 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) C21C 7/10 F27D 1/16

Claims (1)

(57) [Claims] 1. A method for repairing reflux condenser in the vacuum degassing facility, and lowermost the winding bricks constituting the reflux condenser, and an inner winding bricks innermost of the winding in the brick inner forming the upper multiple layers Demolition, and at the dismantling point, the bottom sleeve brick and the front
40 to 60 mm smaller than the outer diameter of the innermost brick
Thickness consisting of an upper sleeve brick with a large outer diameter
A method of repairing a reflux pipe in a vacuum degassing facility, comprising inserting a sleeve brick into the sleeve brick and filling the back of the sleeve brick with an irregular refractory.