JP2002030327A - Method for assembling divided type vacuum vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assembling method with which when a divided type vacuum vessel is assembled, the working time is shortened and the safety is improved. SOLUTION: In the assembling of members vertically dividing the vacuum vessel, at the upper end surface of a lining refractory in the member positioned in the lower side, a weir is arranged and on the upper surface in the range from an iron shell to the weir, monolithic refractory is built up. Successively, the lower end surface of the lining refractory in the member positioned in the upper side is assembled so a to closely stick to the monolithic refractory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assembling a plurality of members into which a vacuum chamber used for vacuum degassing of a molten metal is divided into upper and lower parts, and more particularly to a method for safely preventing an operator from entering the inside of the vacuum chamber. It relates to an assembly method that can work.

[0002]

2. Description of the Related Art Various methods such as an RH method and a DH method are known as vacuum degassing of molten metal such as molten steel. For example, in the case of the RH method for molten steel, as shown in FIG. 4, the pressure in the vacuum tank 1 is reduced, and the molten steel 7 in the ladle 6 is sucked into the vacuum tank 1 via the rising pipe 8 to perform a vacuum degassing process. . The molten steel 7 subjected to the vacuum degassing process in the vacuum chamber 1 is circulated to the ladle 6 through the downcomer 9.

[0003] The refractory lining 3 of the vacuum chamber 1 gradually wears out by performing a vacuum degassing process. Therefore, it is necessary to periodically repair or replace the refractory lining 3. In particular, the refractory lining 3 below the vacuum chamber 1
Due to contact with molten steel and slag, erosion and spalling occur, causing the most severe wear. In order to improve the efficiency of repairing and replacing work of the portion where the refractory lining 3 has been worn, the vacuum chamber 1 is configured to be vertically divided. FIG. 4 shows an example of a configuration in which the vacuum chamber 1 can be divided into three members.

FIG. 3 is a cross-sectional view showing an example of a state of a joint where a lower member 11 and an upper member 12 are fixed using a conventional assembling method. Comparing the thickness of the lining refractory, the lining refractory 3a of the lower member 11 is thicker and the lining refractory 3b of the upper member 12 is thinner. Therefore, after the repair or replacement of the member whose refractory lining has been worn is completed, when assembling the members, as shown in FIG. 3, at the joint between the member 11 located on the lower side and the member 12 located on the upper side. A step is formed on the upper end surface of the lining refractory 3a of the member 11 located on the lower side on the center side of the vacuum chamber.

[0005] As shown in FIG. 3, this step is formed to prevent the air leak by increasing the airtightness of the joint portion. Provided for placing the refractory brick 10 on the floor. However, placing the refractory brick 10 takes a long time. Moreover, since the operator enters the vacuum chamber, it is necessary to prevent the metal or slag attached to the vacuum chamber from falling to the operator. Therefore, there is a problem that it takes a long time to remove the metal and the slag in advance.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and reduces the working time when assembling the vacuum tank after repairing and replacing the refractory lining of the divided vacuum tank. It is another object of the present invention to provide a method for assembling a divided vacuum chamber capable of improving the operation safety.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for assembling a plurality of members obtained by dividing a vacuum chamber used for vacuum degassing of a molten metal into upper and lower parts, and comprising a refractory lining for a lower member. A weir is provided on the center side of the vacuum tank on the upper end surface, an irregular-shaped refractory is placed on the upper end surface of the refractory lining in the range from the inner peripheral surface of the steel shell to the weir, and then the lower end surface of the refractory lining of the member located above is This is a method for assembling a divided vacuum chamber that fixes a member located on the lower side and a member located on the upper side so as to be in close contact with the irregular-shaped refractory.

[0008] In the above-mentioned invention, as a preferred embodiment, the method of laying out an amorphous refractory includes forming a weir by arranging a plastic refractory having plasticity on the inner peripheral surface side of a steel shell to form a plastic refractory. It is preferable that a castable refractory is disposed between the weir to be formed and a weir provided on the center side of the vacuum tank on the upper end surface of the refractory lining.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The assembling method of the present invention is a method of immersing the lower end of a straight-body type vacuum tank in a molten metal, depressurizing the vacuum tank, sucking up the molten metal into the vacuum tank, and performing vacuum degassing. The present invention is applied to a vacuum tank of an apparatus for performing the process, for example, a vacuum tank used for RH vacuum degassing of molten steel, a vacuum tank used for DH vacuum degassing, or the like. These vacuum tanks are configured so that they can be divided into upper and lower parts in order to repair or replace refractory linings.

That is, the vacuum chamber is divided into two or more members, and after repair or replacement of the refractory lining is completed, it is reassembled and used for vacuum degassing. Note that the present invention can be applied when assembling the members of the vacuum tank divided into two or more pieces, and thus the number of divided vacuum tanks is not limited. For example, when dividing the vacuum chamber into three members,
The assembling method of the present invention can be applied to assembling a lower member and an intermediate member, and assembling an intermediate member and an upper member.

When assembling the members of the split type vacuum chamber,
First, as shown in FIG. 2, a weir 4 is provided on the upper end surface of the lining refractory 3a of the member 11 located on the lower side on the center side of the vacuum tank. Weir 4
The material is not limited to a specific type, but it is desirable to use the same type of metal as the molten metal to be subjected to vacuum degassing.
For example, when assembling a vacuum chamber for performing vacuum degassing of molten steel, it is desirable to provide a steel weir 4.

Next, the irregular-shaped refractory 5 is provided in a range from the inner peripheral surface of the steel shell 2 on the upper end face of the lining refractory 3a of the member 11 located on the lower side to the weir 4. As a method of laying, an irregular refractory having a self-shape retaining property (for example, a plastic refractory) is disposed at the time of construction, or an irregular refractory having a self-shape retaining property and an irregular refractory having a fluidity (for example, (Castable refractory).

When an irregular-shaped refractory having a self-shape retention property is arranged, it is preferable to improve the gap filling property after the refractory lining 3a and the lining refractory 3b are brought into close contact with each other. Therefore, it is preferable to use an amorphous refractory which has self-shape retention during construction and exhibits fluidity when a heat load is applied. For example, an amorphous refractory in which a thermoplastic resin is blended as a part of the binder can be suitably used.

When an amorphous refractory having self-shape retention and an amorphous refractory having fluidity are used together, a plastic refractory 5a is arranged on the steel shell 2 side to form a weir, and the plastic refractory is formed. It is preferable to dispose the castable refractory 5b between the weir formed by the object 5a and the weir 4 provided on the upper end surface of the lining refractory at the center of the vacuum tank. Regardless of the method used, the worker does not need to enter the vacuum chamber, and the irregular-shaped refractory 5 can be provided on the upper end face of the lining refractory 3a from outside the vacuum chamber.

Next, the upper member 12 and the lower member 11 are fixed so that the lower end face of the refractory 3b of the upper member 12 is in close contact with the irregular refractory 5. . FIG. 1 is a cross-sectional view showing an example of a state of a joined portion where upper and lower members are assembled by using the assembling method of the present invention. When the member 11 located on the lower side and the member 12 located on the upper side are fixed, the irregular-shaped refractory 5 forms a space formed by the refractory 3b and the weir 4 of the member 12 located on the upper side (hereinafter, referred to as a “weird”). And a gap between the upper end surface of the lining refractory 3a of the member 11 located below and the lower end surface of the lining refractory 3b of the member 12 located above.

The irregular-shaped refractory 5 filled in the irregular-shaped refractory-filled portion corresponds to the refractory brick 10 in the conventional assembling method shown in FIG. In the present invention, the airtightness of the joint is improved by the irregular refractory 5 filled in the irregular refractory filled portion and the irregular refractory 5 filled in the gaps between the lining refractories 3a and 3b. If the maximum height h of the irregular-shaped refractory 5 filled in the irregular-shaped refractory-filled portion is less than 20 cm, an air leak is likely to occur when the irregular-shaped refractory 5 is worn. There is no particular limitation on the upper limit of the maximum height.

The type of the amorphous refractory 5 is not limited to a specific type, but it is preferable to use a plastic refractory 5a and / or a castable refractory 5b in consideration of use at a high temperature. As generally known, the plastic refractory 5a is a refractory obtained by adding water glass (that is, sodium silicate), a plasticizing agent, and an appropriate amount of water as a binder to a refractory aggregate having a controlled particle size and kneading the mixture. Yes,
The castable refractory 5b is a refractory obtained by adding alumina cement or the like as a binder and an appropriate amount of water to a refractory aggregate whose particle size has been adjusted and kneading the mixture.

[0018]

EXAMPLE A vacuum degassing treatment was carried out by making the vacuum tank 1 of a RH vacuum degassing apparatus for molten steel of 260 t scale as shown in FIG. After replacing the refractory lining 3a of the lower member (hereinafter referred to as the lower tank), which is the most severely worn due to contact with molten steel or slag, of the three members, the vacuum tank is formed by using the assembling method of the present invention. 1 was assembled.

That is, after relining the refractory 3a of the lower tank, as shown in FIG. 2, the refractory 3a of the lower tank
A weir 4 is provided at the upper end surface on the center side of the vacuum tank, and a plastic refractory 5a is provided between the steel shell 2 and the weir 4 to form a weir. Between the weir 4 formed of the plastic refractory 5a and the weir 4 Castable refractory 5b was served. The plastic refractory 5a and the castable refractory 5b are provided by an operator by pouring from the outside of the vacuum chamber 1 and the amount of the refractory 5 filled in the irregular refractory filled portion after the vacuum chamber 1 is assembled. The maximum height h was set to 20 cm. The width of the filled portion of the refractory was determined by the position of the weir 4, and was 10 cm.

Next, as shown in FIG. 1, a member positioned above the lower tank (hereinafter referred to as an intermediate tank) was fixed so that the lower end surface of the refractory 3b of the member was in close contact with the irregular refractory 5. This is an invention example. Next, as a comparative example, vacuum degassing was performed using the same apparatus, and the refractory lining 3a of the lower tank was replaced, and then adhered to the lining refractory of the intermediate tank and the upper member (hereinafter referred to as the upper lid tank). Ingots and slag were removed. Next, as shown in FIG. 3, the lower tank and the intermediate tank were fixed without using the irregular-shaped refractory. In addition, the worker enters the vacuum chamber and the refractory lining the lower tank.
3a, a refractory brick 10 was arranged on the upper side of the vacuum chamber at the center.

In the example of the invention, since the worker does not enter the tank at the time of assembling, the work of removing the metal and slag adhered to the intermediate tank and the upper lid tank for ensuring safety can be omitted. The required time was 4 hours. On the other hand, in the comparative example, the vacuum tank 1
It took 8 hours to assemble. Moreover, in the invention example, the worker does not need to enter the vacuum chamber 1 and can work outside the vacuum chamber 1, so that the safety is greatly improved. After the operation is resumed, the degree of vacuum is 133 Pa (that is, 0.1 torr).
Reached.

[0022]

According to the present invention, since the vacuum chamber can be assembled without the operator entering the vacuum chamber, the assembling time can be reduced and the safety can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a state of a joint where upper and lower members are fixed using the method of the present invention.

FIG. 2 is a cross-sectional view showing an example of a state in which a weir is provided on an upper end surface of a refractory lining and an irregular refractory is provided using the method of the present invention.

FIG. 3 is a cross-sectional view showing an example of a state of a joint where upper and lower members are fixed using a conventional method.

FIG. 4 is a sectional view showing an example of an RH vacuum degassing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Steel shell 3 Lining refractory 3a Lining refractory of the member located below 3b Lining refractory of the member located above 4 Weir 5 Irregular refractory 5a Plastic refractory 5b Castable refractory 6 Ladle 7 Molten steel 8 Ascending pipe 9 Downcoming pipe 10 Refractory brick 11 Member located below 12 Member located above

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Misono 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Chiba Works, Ltd. F term in Chiba Works (reference) 4K013 BA07 CE01 4K051 AA06 AB03 BB03 BG03

Claims (2)

[Claims] 1. A method for assembling a plurality of members obtained by dividing a vacuum chamber used for vacuum degassing of a molten metal into upper and lower parts, comprising: A weir is provided, and an irregular-shaped refractory is provided on an upper end surface of the refractory lining in a range from the inner peripheral surface of the steel shell to the weir,
Next, the member located on the lower side and the member located on the upper side are fixed so that the lower end surface of the lining refractory of the member located on the upper side is in close contact with the irregular refractory, How to assemble. 2. A method for laying out irregular shaped refractories, comprising: forming a weir by arranging a plastic refractory having flexibility on an inner peripheral surface side of the steel shell; and forming the weir formed by the plastic refractory and the lining. The method according to claim 1, wherein a castable refractory is disposed between the upper end of the refractory and a weir provided on the center side of the vacuum tank.