JPH0820815A - Method for repairing reflux pipe of vacuum degassing equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for repairing a return pipe in a vacuum degassing facility. [Structure] First, a bottom-layer inner-wall brick that constitutes the reflux pipe A and a first-layer inner-layer brick in which the upper layer is formed into a plurality of layers are disassembled, and then a large-sized wall with a large wall thickness After the sleeve brick 6 is inserted, the rear surface of the sleeve brick 6 is filled with the irregular refractory 9 through the press-fitting pipe 8 to repair the reflux pipe A. [Effect] During operation, when the inner winding brick forming the return pipe is cracked or has a joint breakage, or the inner winding brick is damaged by the flow of molten steel or the like, repair is performed by applying the above repair method of the present invention. It is possible to significantly reduce the number of times, moreover, it is possible to match the repair time of the reflux pipe A and the replacement time of the immersion pipe at the same time, and significantly extend the life of the entire lower tank. it can.

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 in particular, the life of the tank can be greatly extended by disassembling and repairing an inner brick at the opening of the tank bottom. Regarding repair methods. In the present invention, the “recirculation pipe” refers to a circulation 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) dip pipes at the lower end, and each part has its own part. A suitable material is selected according to the amount of wear and lining is applied.

The life of the lining at each of these parts is generally the part where the flow velocity of the molten steel reaches the maximum and bubble explosion etc. occur, and the tank bottom opening, that is, the reflux pipe opening, which is most easily damaged. It is often governed by the state of damage to the part. Since this part is located between the tank and the dip pipe, it cannot be easily replaced like the dip pipe. Therefore, various techniques have been conventionally applied to the brick stacking and the repairing method. ing.

Regarding brickwork, for example, a tank bottom structure of a vacuum processing apparatus has been proposed (see Japanese Utility Model Publication No. 63-11166). This brick-laying structure at the bottom of the tank (hereinafter referred to as "conventional brick-laying structure at the bottom of the tank") will be described with reference to FIG. 6 as follows: "Brick-laying structure at the bottom of the tank of a vacuum processing apparatus having an immersion pipe". In the above, a brick pile around the tank bottom opening 21 connected to the dipping pipe is replaced with a small horizontal brick 22.
a and 22b are arranged in a plurality of turns, and a bottom of the plurality of turns and a bottom brick 23 are provided with a filling layer of an indefinite refractory material 24. Structure.

Further, as a method of repairing the opening of the reflux pipe,
For example, a method for repairing a reflux pipe of a vacuum degassing device has been proposed (see Japanese Patent Laid-Open No. 60-215712). This repairing method (hereinafter referred to as “conventional repairing method”) will be described with reference to FIG. 7 by referring to “a refractory sleeve 31 on the immersion pipe B”.
After being 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 between the wear portion of the reflux pipe and the refractory sleeve 31. The present invention relates to a method for repairing a reflux pipe of a vacuum degassing device, which is characterized by filling an irregular refractory material 32. Note that FIG.
In the figure, 33 is a press-fitting pipe, and 34 is a flange.

[0006]

However, as is well known, the reflux pipe opening of the lower tank in the RH type vacuum degassing equipment is vacuum degassed by immersing the dipping pipe attached to the lower part in the molten steel in the ladle. When gas treatment is performed, wear caused by shocking turbulence due to high temperature of molten steel and recirculation of molten steel,
Alternatively, spurting is generated and promoted by rapid heating / cooling due to repeated use, resulting in damage.

In the conventional brick-laying structure at the bottom of the tank described above, when the dipping pipe is immersed in the molten steel in the ladle for vacuum degassing treatment, the high temperature of the molten steel causes expansion of the iron shell on the outer periphery of the tank bottom. However, due to the deformation of the bottom of the can body tank, the horizontal joints of the inner layer side-by-side bricks formed by stacking multiple layers open,
The part is prematurely damaged due to acceleration.

Further, in the case of an irregular shaped refractory filling layer provided between the outer layer lateral brick and the brick, the filling layer is provided with a width of about 20 mm at a position about 300 to 400 mm away from the peripheral edge of the opening. However, it is not possible to sufficiently absorb the expansion of the floor brick and the inner and outer layer side-by-side bricks. For this reason, cracks mainly occur in the innermost horizontal bricks in the uppermost stage, and these cracks develop rapidly due to the difference in specific gravity from the molten steel and the flow of molten steel that rises in turbulent flow. The brick advancing sideways on the innermost layer on the center side of the bottom peels off and floats, which accelerates the damage.

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 unevenness may occur on the opening surface due to local damage of the lining brick, adhesion of metal, or the wall side. Compared to the above, the center side of the bottom of the tank is more damaged. Therefore, if a refractory sleeve is fitted in the inner hole of the immersion pipe and placed concentrically, the refractory sleeve
In some cases, the refractory sleeve to be inserted may not only not have a uniform repair thickness due to the irregular refractory filling between the damaged portion of the reflux pipe and the refractory sleeve. Generally, since it is formed of a thin refractory brick having a wall thickness dimension of about 10 to 65 mm, it has a limited number of useful lives and must be frequently repaired.

Further, each part of the lower tank is lined by selecting an appropriate material according to the amount of wear, but generally, the reflux pipe opening is damaged faster than the side wall. . Therefore, in order to extend the service life to a greater extent than in the past, it is desired to establish a repair method in which a sleeve brick having a large wall thickness can be inserted into the opening and the repair can be performed easily. Has been done.

The present inventors succeeded in developing the repairing method of the present invention as a result of various examinations and experiments in order to solve various problems in the conventional brick-laying structure and the repairing method for the bottom of the tank. Therefore, an object of the present invention is to provide a repair method that not only can prolong the life of the reflux pipe opening, which is most liable to be damaged, but also can easily and easily repair the damaged portion. To provide.

[0012]

The repair method according to the present invention is, "In the method for repairing a reflux pipe in a vacuum degassing facility, the innermost brick at the lowermost stage forming the reflux pipe and its upper stage are formed in a plurality of layers. A method for repairing a reflux pipe of a vacuum degassing equipment, characterized by disassembling the first-layer inner brick and inserting the sleeve brick, and filling the rear surface of the sleeve brick with an amorphous refractory . "Is the gist (technical constitution), and thereby the above-mentioned object of the present invention is achieved.

That is, according to the present invention, by adopting such a technical constitution, it is possible to insert and repair a sleeve brick having a large wall thickness and, if necessary, newly install the bottom lined brick. It is also possible to re-load to the rear, and to make the irregular refractory to be filled on the back even thickness, so that the locally pre-damaged portion of the reflux pipe opening, which is most likely to be damaged, can be extended with a small number of repairs. Therefore, there is an effect that the life of the entire lower tank can be greatly extended.

The reflux pipe for the conventional RH vacuum degassing equipment is
For example, it consists of magnesia, chrome, high alumina, etc.,
Brick with a predetermined shape that has a predetermined inner diameter and wall thickness, and is divided into a plurality of bricks in the circumferential direction according to the size of the reflux pipe for RH type vacuum degassing equipment. It is formed to have a one-layer structure in total or a two-layer structure in which an outer winding brick is arranged on the outer periphery of the upper part. However, in such a conventional reflux tube for a RH type vacuum degassing facility, cracking occurs when it is used while repeating rapid heating and rapid cooling.
The joints may be broken or rapidly damaged by the flow of molten steel that circulates while flowing turbulently.

Here, the method for repairing the reflux pipe according to the present invention will be described in detail with reference to FIGS. 1 shows the structure of a reflux pipe suitable for carrying out the repairing method of the present invention, and FIG. 2 shows the structure of the periphery of the reflux pipe. 3 and 4 are a longitudinal sectional view and a transverse sectional view 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.

The reflux pipe A suitable for carrying out the repairing method of the present invention is, as shown in FIG. 2, (1) an annular brick having a predetermined shape divided into a plurality of pieces in the circumferential direction. Inner-walled bricks 1 arranged in multiple layers and stacked in multiple stages, (2) Middle-sized bricks 2 in which laterally-arranging bricks, which are also divided into a plurality of pieces in the circumferential direction, are annularly arranged, and (3) Floor bricks 4 The outer-wrapping brick 3 has a shape determined so as to have an octagonal shape in order to improve the arrangement with
And are formed as a three-layer structure. In addition,
In addition to the shape of the outer-wrapped brick 3, it is possible to select a shape such as an irregular quadrangle, a circle, or a petal shape, a part of which is shown in the portion W in FIG.

The reflux pipe A will be further described. As shown in FIG. 1, the reflux pipe A has a first layer (opening side) inner brick 1b in which the upper part of the reflux pipe A is formed in a plurality of layers. In order to support the middle-sized brick 2, an innermost-covered brick 1a at the bottom is arranged. The lowermost inner-layer brick 1a has a one-layer structure, and the lower back surface side thereof is formed in a tapered shape in conformity with the shape of the flange 5 (see FIG. 5). The bottom inner brick 1a has a flange 5 (see FIG. 5).
It is possible to select a form such as forming an L-shaped cross section according to the shape of the above.

On the other hand, the first-layer inward-wound brick 1b has a thick wall thickness so that the sleeve brick 6 (see FIGS. 3 and 4: plan view of FIG. 3) can be inserted. The wall thickness is set to 120 mm or more, preferably 150 mm or more.

The sleeve brick 6 has a predetermined inner diameter and height. That is, the inner 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 the a and 1b are dismantled. ,
30 to 50 more than the height of the innermost brick 1a at the bottom of the reflux pipe A
It is set about mm lower. As shown in FIGS. 3 and 4, the sleeve brick 6 is composed of a lowermost sleeve brick 6a which is divided into a plurality of pieces in the circumferential direction, and an outer diameter dimension in the first layer of the reflux pipe A. Than the outer diameter of the rolled brick 1b (see Fig. 1)
It is configured by stacking a plurality of upper sleeve bricks 6b, which are divided into a plurality of pieces in the circumferential direction with a small size of 40 to 60 mm.

As shown in FIG. 3, a through hole 6c for connecting the press-fitting pipe 8 (see FIG. 5) is bored at a predetermined position of the upper sleeve brick 6b, and these are integrated structure before repair. 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 the vertical joints of the upper sleeve brick 6b which is divided into a plurality of pieces in the circumferential direction of the reflux pipe A. It is placed in multiple places.

Further, according to the present invention, cracks, joint breakage, etc. occur in the inner 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 wall thickness of the inner-wall brick 1 becomes thin due to damage caused by the flow of molten steel that is turbulently refluxing. Specifically, the present invention dismantles the innermost-walled brick 1a at the bottom shown in FIG. 1 and the first-layered internally-covered brick 1b in which the upper layer is formed in a plurality of layers, and subsequently shown in FIGS. 3 and 4. After inserting the sleeve bricks 6a and 6b, as shown in FIG. 5, the sleeve bricks 6a and 6b are inserted.
The rear surface of 6b is filled with an irregular refractory 9 through 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, the sleeve bricks 6 are placed concentrically on the dip pipe (not shown), and the flange 5
The immersion pipe is attached to the recirculation pipe A through the pipe, so that the sleeve brick 6 is placed in the recirculation pipe A in which the inwardly wound brick 1 is dismantled.
Insert. Incidentally, when the sleeve brick 6 is inserted into the reflux pipe A, the sleeve brick 6 can be placed on a pedestal which can be raised and lowered and inserted. Next, a press-fitting pipe 8 is connected to a through hole 6c (see FIG. 3) provided at a predetermined position of the sleeve brick 6, and the irregular refractory 9 is attached to the back surface of the sleeve brick 6 through the press-fitting pipe 8. And the reflux pipe A is repaired.

According to the method for repairing a return pipe according to the present invention,
As described in detail above, the three-layer structure of the reflux pipe A (see FIGS. 1 and 2) not only allows the inner brick 1 to be dismantled even while hot, but also increases the wall thickness. Even if the inner brick 1 is dismantled and the middle brick 2 of the second layer is damaged even if the sleeve brick 6 having a large dimension can be inserted, the outer brick of the third layer is damaged. The presence of 3 makes it possible to secure the strength of the structure. Further, the expansion absorber 7 (see FIG. 4) is interposed in the vertical joint portion of the sleeve brick 6 to absorb the expansion of the sleeve brick 6 and to cause the deformation of the bottom of the can body tank. It is possible to suppress the occurrence of cracks, joint breaks, and the like.

Further, the innermost-wrapped brick 1a (see FIG. 1) of the reflux pipe A adheres to the brick for the dipping pipe and is peeled off when the dipping pipe is removed. If there is a local preceding damage due to the difference, the innermost brick 1 at the bottom
It is also possible to partially repair by dismantling only a and newly reloading only the innermost brick 1a at the bottom.

[0025]

EXAMPLES Next, the present invention will be described in more detail with reference to an example of the method for repairing the reflux pipe of the vacuum degassing equipment according to the present invention, but the present invention is not limited to this example. Absent.

In this embodiment, the reflux pipe 3 shown in FIG. 1 is used.
This is a layered reflux pipe A, which is applied to an RH type vacuum degassing facility of 250 T / ch., And the reflux brick 6 (6a, 6b) shown in FIGS. 3 and 4 is used. Repaired A. First, after removing the immersion pipe from the reflux pipe A, the innermost-walled brick 1a at the lowermost stage and the first-layered inner-layered brick 1b having a plurality of upper stages thereof were disassembled by using a breaker.

Next, the upper sleeve brick 6b having an outer diameter smaller than the inner diameter of the middle-sized brick 2 (see FIG. 1) by 60 mm.
(Wall thickness: 120 mm), the outer diameter of which is 10 mm smaller than the inner diameter of the flange 5 (see FIG. 5), and the height of which is 50 mm lower than the innermost brick 1a of the reflux pipe A. The sleeve bricks 6a were stacked, and the sleeve bricks 6 (see FIG. 3) which had a predetermined inner diameter and height and had an integral structure before repair were placed concentrically on the dip pipe.

Subsequently, the dip tube on which the above-mentioned sleeve brick 6 was placed was attached to the reflux pipe A, and the sleeve brick 6 was inserted into the reflux pipe A in which the inwardly wound brick 1 was dismantled in this manner. After that, a press-fitting 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 the press-fitting pipe 8 is inserted into a gap formed on the back surface of the sleeve brick 6. The irregular shaped refractory 9 (see FIG. 5) was filled and repaired.

According to the repair method of this embodiment, the number of repairs can be reduced to one half or less as compared with the conventional repair method using the sleeve brick having a small wall thickness. In addition, there is an effect that the complexity at the time of inserting the sleeve brick, which is caused by the unevenness of damage of the reflux pipe A, is eliminated. As a result, the repair time is not extended, and the repair of the reflux pipe A and the replacement of the immersion pipe can be performed at the same time in accordance with the damage condition of the immersion pipe.

[0030]

EFFECTS OF THE INVENTION According to the present invention, when the inner-wall brick forming the recirculation pipe during operation is cracked, the joint is broken, or the inner-wall brick is damaged by the flow of molten steel that recirculates while turbulently flowing, It is not possible to insert a sleeve brick like the conventional repair method (method described in Japanese Patent Laid-Open No. 60-215712), or without causing a situation in which repair must be performed frequently, By inserting a sleeve brick with a large wall thickness by disassembling the damaged inner winding brick, the effect of being able to systematically repair occurs, and as a result, the number of repairs can be significantly reduced, In addition, there is a remarkable effect that the repairing time of the reflux pipe and the replacement time of the immersion pipe can be matched with each other so that they can be carried out at the same time.

Further, unlike the conventional brick-laying structure at the bottom of the tank (the structure described in Japanese Utility Model Publication No. 63-11166), absorption of expansion stress of bricks or deformation stress of the can is not insufficient, and Even if a large-sized sleeve brick with a large thickness is inserted, the occurrence of cracks, joint breakage, etc. can be suppressed,
By prolonging the life of the reflux pipe opening, which is most likely to be damaged, the life of the entire lower tank can be significantly extended.

[Brief description of drawings]

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

FIG. 2 is a plan view showing the structure around the reflux pipe of FIG.

FIG. 3 is a vertical 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.

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

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

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

[Explanation of symbols]

 1 Inner Brick 1a Bottom Inner Brick 1b 1st Layer Inner Brick 2 Middle Brick 3 Outer Brick 4 Floor Brick 5 Flange 6 Sleeve Brick 6a Bottom Slave Brick 6b Upper Slave Brick 6c Through Hole 7 Expansion absorber 8 Press-in pipe 9 Irregular refractory 21 Tank bottom opening 22a, 22b Horizontal brick 23 Bottom brick 24 Irregular refractory 31 Refractory sleeve 32 Irregular refractory 33 Press-in pipe 34 Flange A Circulation tube B Immersion tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Yamamoto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Masaaki Nishi Nishi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe (72) Inventor Hiroshi Mitani 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) Inventor Kazuhiko Araki 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Tube Co., Ltd.

Claims (2)

[Claims] 1. A method for repairing a reflux pipe in a vacuum degassing facility, wherein a bottom inner-wall brick constituting the reflux pipe and a first-layer inner-wall brick having a plurality of upper layers are disassembled and slid. A method for repairing a reflux pipe of a vacuum degassing equipment, which comprises inserting a brick and filling the rear surface of the sleeve brick with an amorphous refractory. 2. A method for repairing a reflux pipe in a vacuum degassing equipment, which comprises dismantling and reloading the innermost bricks constituting the reflux pipe.