JPH09263823A - Refractory for immersion tube and its manufacture and immersion tube lined with this refractory and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an immersion tube having high durability by strengthening the support of bricks and rising the strength of the whole bricks in order to make it possible to use the brick and a precast refractory at the outer periphery and the lower end of the immersion tube of a degassing apparatus used to molten metal refining. SOLUTION: A metallic body 1 having the length of at least >=1/2 of the refractory length and either shape among a wire-, bar- or plate-like, is embedded in the refractory lined on the outer periphery or the lower end of a core metal 3 or fitted on the side surface of the core. Bridge body 3 extended from the metallic body 1 for connecting, and fixing this metallic body 1 with the core metal 3 is exposed or projected on the refractory surface of the core metal side at least in one place to form the immersion tube made of the fixed shape and the precast refractory. As a result, the refractory is firmly fixed to the core metal 3 with the bridge body 2, and the refractory itself is reinforced with the metallic body 1 and the immersion tube having high durability is obtd.

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 a degassing apparatus used for refining molten metal, a refractory used therein, a method for producing the same, and a dip tube constructed with the refractory. The construction method is provided.

[0002]

2. Description of the Related Art As the quality of steel becomes higher and higher, the importance of secondary refining in iron and steel refining, especially degassing processes such as RH and DH, is increasing, and the refining process content is refractory in the degassing tank. It is tough for things. Even under such circumstances, reduction of steel manufacturing cost is an important issue, and research and development are being made every day on the material, structure, repair, or operating method of refractory materials. An immersion pipe can be mentioned as one of the parts in the degassing equipment where wear is large. This dipping pipe is usually located at the lower end of the degassing tank and is a part to be immersed in the molten steel in the ladle when sucking the molten steel into the tank. The length and thickness of the immersion pipe vary depending on the type and capacity of the degassing tank, and the approximate length is 50.
The thickness is 0 mm to 2000 mm, and the outer diameter is 500 mm to 3500 mm. The name is usually a dip tube, but it may also be called a dip tank or a suction pipe. Generally, the immersion pipe and degassing tank are connected by a flange or welding. On the other hand, the dip tube is composed of a core metal and a refractory material. The core metal, which corresponds to the skeleton of the immersion tube, is also called an iron core, and is usually a cylinder made of metal such as iron. Refractory is applied to the inner and outer circumferences, and normally bricks are applied to the inner circumference and castables are applied to the outer circumference.

The refractory material applied to the outer circumference of the dip pipe is attacked by the slag on the molten steel in the ladle, and the refractory material applied to the inner circumference is a gas blown to wear the molten steel or to recirculate the molten steel. Affected by. In addition, spalling is likely to occur on both the inner and outer circumferences due to thermal shock caused by repeated immersion in molten steel and cooling after the treatment. As mentioned above, castable refractories are often used on the outer periphery, but cracks occur due to spalling caused by thermal shock, and the atmosphere penetrates into the tank from these cracks, and the nitrogen concentration in the molten steel is increased. There is a phenomenon that the temperature does not drop or the nitrogen concentration rises, so-called nitrogen pickup.

Further, the lower end of the cored bar of the dip tube is often deformed like a trumpet during use, and the refractory material applied to the inner and outer circumferences often falls off. As one of the measures to solve these problems, a dip pipe with a durable refractory such as bricks or precast refractory on the outer circumference is used.
No. 8-135457 or Japanese Patent Laid-Open No. 7-341119. In these inventions and inventions, the use of standard bricks with excellent corrosion resistance and spall resistance on the outer circumference of the dip pipe ensures high corrosion resistance and spalling resistance against slag on the ladle content steel. There is. Further, since it is structurally more stable than the case where castable refractory is used, cracks are less likely to occur, and nitrogen pickup is less likely to occur.

[0005]

However, in these conventional techniques, since the bricks installed on the outer periphery of the dipping pipe are instructed by sandwiching them vertically with a metal object, if the indicator metal object is damaged by any chance. As a result, bricks around the periphery fall off in no time, and the dipping pipe must be discarded. Especially when degassing the high temperature molten steel for a long time, the indicator metal at the lower end of the outer peripheral brick may be damaged under high temperature. Also, when removing the slag adhering to the outer circumference of the dip pipe, a large force is applied to the outer brick,
Brick may break. In order to solve these problems, it is necessary to strengthen the instructions for bricks and to increase the overall strength of the bricks.

[0006]

Means for Solving the Problems As a result of diligent examination of measures for achieving the above, the following invention was obtained. That is, first, a refractory for a dip tube to be installed on the outer circumference of the core metal or the lower end of the core of the dip tube is as follows. A wire-shaped, rod-shaped, or plate-shaped metal body having a length of at least half or more of the refractory is embedded in the refractory or attached to the core metal side surface. For connecting and fixing the body to the core metal, a crosslinked body extending from the metal body,
It is a standard or precast refractory that is exposed or protrudes on the core metal side surface of at least one or more of the refractory.

There are several methods for producing such a refractory for a dip tube. Here, the following five methods are proposed. All of them are for producing a refractory material by using a mold, and (1) a core, the metal body of which is a linear, rod-shaped, or plate-shaped metal body having at least half the length of the mold. After placing the refractory reinforcement with at least one crosslinked body attached to and fixed to the mold so as to contact the inner bottom surface or the inner side surface of the mold, pour the kneaded material or the kneading body into the regular shape. Or manufacture precast refractory.

(2) After charging the kneaded material or a part of the kneaded body into the mold, a linear shape having a length of at least half or more of the mold,
A refractory reinforcement body in which at least one cross-linking body for connecting and fixing the metal body to a core metal is attached to any one of a rod-shaped or plate-shaped metal body is contacted with the inner bottom surface or the inner side surface of the mold. Then, the remaining kneaded material or the kneaded body is charged, and a standard or precast refractory material is manufactured.

(3) At least one cross-linked body for connecting and fixing the metal body to the cored bar on any of the linear, rod-shaped, and plate-shaped metal bodies having a length of at least half the length of the mold. The refractory reinforced body attached at the above positions is provided with a recess for inserting a part or all of the crosslinked body on the inner bottom surface or the inner side surface of the mold, and after inserting the crosslinked body of the refractory reinforcement into the dent, Soil or kneaded material is charged to produce a standard or precast refractory.

(4) At least one cross-linked body for connecting and fixing the metal body to the cored bar on any of the linear, rod-shaped, and plate-shaped metal bodies having at least half the length of the mold or more. The refractory reinforcement that is attached above is suspended in a mold, and the kneading body is poured into the mold to produce a precast refractory.

(5) After pouring the kneading body into the mold, the metal body is connected and fixed to a cored bar to any one of linear, rod-shaped and plate-shaped metal bodies having at least half the length of the mold. A precast refractory is manufactured by inserting a refractory reinforcement to which at least one cross-linking body is attached into a mold.

By connecting and fixing the immersion pipe refractory obtained as described above to the outer circumference or the lower end of the immersion pipe core metal through the crosslinked body of the refractory, the desired immersion pipe of the present invention is obtained. can get. When constructing such a dip pipe, the cross-linked body of the refractory for a dip pipe as it is, or the length of the cross-linked body is extended, or a new cross-linked body is attached to the metal body, and the cross-linked body is cored. It shall be connected and fixed to the outer circumference or bottom of the gold.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An example of a dip tube according to the present invention will be described below with reference to the sectional view of FIG. 1 and the explanatory view of FIG. In the present invention, a refractory reinforcement as shown in FIG. 2 is present inside or on the surface of the refractory to be installed on the outer circumference or the lower end of the dip tube. This refractory reinforcement comprises a linear, rod-shaped or plate-shaped metal body 1 and a crosslinked body 2 fixed to the metal body 1.

In FIG. 1, a metal body 1 is provided inside a peripheral refractory material 5.
Is embedded. This metal body 1
Has a function to reinforce the outer peripheral refractory 5, so that the outer peripheral refractory 5 is not broken even if some force is applied due to removal of the adhered slag. A cross-linked body 2 extending in the direction of the core metal 3 on the back surface of the outer peripheral refractory 5 is attached to the metal body 1, and its tip is welded to the core metal 3. As a result, the outer peripheral refractory 5 is firmly fixed to the core metal 3, and it is not necessary to support the brick at the lower end of the dipping tube where the temperature easily rises. It is desirable to apply an outer filler 9 between the outer peripheral refractory 5 and the core metal 3 in preparation for intrusion of bare metal.

The inner peripheral refractory material 6 and the lower end refractory material 7 of the core metal 3 have no problem in the conventional materials and construction methods. FIG. 1 shows an inner peripheral refractory 6 supported on the inner periphery by an inner peripheral refractory supporting metal 11.
And an inner filler 10 and a lower end refractory 7 supported by studs 8 at the lower end are shown. As a method of manufacturing a refractory having a refractory reinforcement and being applied to the outer periphery or the lower end, there are the following methods. That is, after placing the refractory reinforcement so as to contact the inner bottom surface or the inner side surface of the mold, a method of charging the kneaded clay or the kneading body, after charging a part of the kneaded clay or the kneading body, The refractory reinforcement is placed so as to be in contact with the inner bottom surface or the inner side surface of the mold, and further, a method of charging the remaining kneaded clay or a kneading body, a recess for inserting a part or all of the crosslinked body of the mold This is a method in which a kneaded material or a kneaded body is charged after the crosslinked body of the refractory material is inserted into the recess provided on the inner bottom surface or the inner side surface. These are all methods for producing a standard refractory material or precast refractory material that is subjected to pressure molding, rammer molding or stamp molding.

On the other hand, with respect to the precast refractory, since the kneaded body has a high fluidity, a method of suspending the refractory reinforcement body in the mold and then pouring the kneaded body, after pouring the kneaded body into the mold The method of inserting the refractory reinforcement into the mold can also be used. The cross-linked body 2 and the metal body 1 may be integrally formed, or may be welded in advance or fixed to the metal body 1 by screws or fitting. The cross-linked body 2 does not necessarily have to be projected on the refractory surface, and the metal body 1 or the cross-linked body 2 is exposed on the refractory surface, and a rod or the like for extension is welded or screwed to the metal body 1 or the cross-linked body 2. It is also possible to connect them by fitting to form the crosslinked body 2.

The material of the metal body is usually ordinary steel, and there is no problem.
However, when high temperature strength and the like are particularly required, it is desirable to use stainless steel or heat resistant steel. Moreover, examples of the cross-sectional shape of the metal body include a circle, an ellipse, a square, a rectangle, a mountain shape, an L shape, an H shape, and an I shape. Circular pipe,
Although hollow pipes such as square pipes can be used, it is better not to use them if they may be damaged when molded as an outer peripheral refractory. The same applies to the material and cross-sectional shape of the crosslinked body.

The material of the outer peripheral refractory 5 may be appropriately selected depending on the operating conditions. In the case of RH and DH immersion pipes, M is generally used as a material that can achieve both corrosion resistance and spall resistance.
gO-C brick is suitable. However, other materials may be selected depending on the case. Further, not only bricks, but also precast amorphous refractories are possible. As a method for supporting the outer peripheral refractory material in the present invention, a conventional brick supporting method, for example, Jitsukai Sho 58-1354 is used.
There is no problem even if the method of supporting from above and below as disclosed in Japanese Patent Laid-Open No. 57-57 or Japanese Patent Application Laid-Open No. 7-341119 is used together. Rather, it can be supported more reliably. Further, the cored bar of the immersion pipe in the present invention is a cored bar having a double jacket and a cooling medium is allowed to flow between the cored bar and the cored bar, or the pipe is run along the cored bar to flow the cooling medium. You may use the core metal etc. which were made to cool.

FIG. 3 shows a case where a refractory having the metal body 1 provided on the surface of the core metal is applied to the outer circumference of the dip tube. Metal body 1
When the refractory was manufactured, the refractory was placed on the inner bottom surface of the mold, and then the whole body of kneaded clay was charged to form the refractory.
In order to prevent the metal body 1 from peeling off from the outer peripheral refractory 5, the metal body 1 is provided with a protrusion 12.

Further, FIG. 4 shows an example in which a brick having a metal body embedded therein is used on the outer circumference and the lower end of the dipping tube. At the lower end of the submerged pipe, which is prone to erosion, it is preferable to construct a standard refractory material such as a high-resistant brick, and if a normal brick is used, spalling often occurs and the brick falls off, so be careful. It costs. In the present invention, by making the lower end brick, it was possible to realize a stable immersion tube having a longer life than conventional ones.

Further, FIG. 5 shows an example in which a refractory material in which a metal body is embedded is applied to the outer circumference of the dip tube and the length thereof is extended to the lower end of the dip tube. When a fixed refractory such as a brick without a metal body is extended to the lower end of the dip tube, the lower end usually cracks and falls off. However, in the present invention, since the refractory material in which the metal body is embedded is adopted, cracking can be prevented.

[0022]

Industrial Applicability According to the present invention, a highly durable dip tube having a refractory material such as brick on its outer periphery and lower end can be obtained. As a result, the life of the immersion pipe can be extended, the operation can be stabilized and the refractory unit consumption can be reduced, which greatly contributes to the reduction of steel manufacturing costs.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a dip tube in which a refractory having a metal body inside is applied to the outer periphery of a cored bar.

FIG. 2 is a schematic explanatory diagram of a refractory reinforcement.

FIG. 3 is a cross-sectional view of a dip tube in which a refractory having a metal body provided on the surface is applied to the outer periphery of a cored bar.

FIG. 4 is a cross-sectional view of a dip tube in which a refractory material provided with a metal body inside is applied to the outer periphery of the cored bar and the lower end of the cored bar.

FIG. 5 is a cross-sectional view of an immersion pipe in which a working range of an outer peripheral refractory having a metal body provided therein is extended to a lower end of the immersion pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal body 2 Crosslinked body 3 Core metal 4 Flange 5 Outer peripheral refractory material 6 Inner peripheral refractory material 7 Lower end refractory material 8 Stud 9 Outer filling material 10 Inner filling material 11 Inner peripheral refractory material 12 Metal protrusion

Claims (8)

[Claims] 1. A refractory to be applied to the outer periphery of the cored bar or the lower end of the cored bar of the dip tube, which has a length of at least half or more of the refractory and is a linear, rod-shaped or plate-shaped metal body. But,
At least one or more cross-linking bodies embedded in the refractory or attached to the surface of the core metal and extending from the metal body for connecting and fixing the metal body to the core metal are provided. A standard or precast refractory for immersion pipes that is exposed or protruding on the core metal side surface of the refractory. 2. When manufacturing a refractory for an immersion pipe using a mold, a metal core is provided on a linear, rod-shaped, or plate-shaped metal body having at least half the length of the mold. After placing the refractory reinforcement with at least one crosslinked body attached to and fixed to the mold so as to contact the inner bottom surface or the inner side surface of the mold, pour the kneaded material or the kneading body into the regular shape. Or a method for producing a refractory for a dip pipe, which comprises producing a precast refractory. 3. When manufacturing a refractory for an immersion pipe using a mold, after charging a kneaded clay or a part of the kneaded body into the mold, a linear shape, a rod shape, or a shape having a length of at least half or more of the shape, A refractory reinforcement body, in which at least one cross-linking body for connecting and fixing the metal body to a core metal is attached to one of the plate-shaped metal bodies, is contacted with the inner bottom surface or the inner side surface of the mold. A method for producing a refractory for a dip pipe, characterized by comprising placing the remaining kneaded material or a kneaded body to produce a refractory having a regular shape or precast. 4. When manufacturing a refractory for an immersion pipe using a mold, a metal core is provided on a linear, rod-shaped, or plate-shaped metal body having at least half the length of the mold. A refractory reinforcement having at least one crosslinked body for connecting and fixing to, a recess for inserting a part or all of the crosslinked body is provided on the inner bottom surface or the inner side surface of the mold, and the recess is A method for producing a refractory for a submerged pipe, comprising inserting a kneaded material or a kneaded body after inserting a crosslinked body of a refractory reinforcement, and producing a refractory of a fixed shape or precast. 5. When manufacturing a refractory for a dip tube using a mold, the core is made of a linear, rod-shaped, or plate-shaped metal body having at least half the length of the mold. A refractory for a submerged pipe, characterized in that a refractory reinforcement having at least one crosslinked body attached to and fixed to is suspended in a mold and the kneading body is poured to produce a precast refractory. Manufacturing method. 6. When manufacturing a refractory for a dip tube using a mold, after pouring the kneading body into the mold, at least half or more of the length of the mold is one of linear, rod-shaped, and plate-shaped metal. A refractory reinforcement body having at least one crosslinked body for connecting and fixing the metal body to a core bar is inserted into a mold to produce a precast refractory body. A method for manufacturing a refractory for a dip pipe. 7. A dip tube characterized in that the refractory for a dip tube according to claim 1 is connected and fixed to the outer periphery or the lower end of a core metal through a cross-linked body of the refractory. 8. The crosslinked body of the refractory for a dip tube according to claim 1 as it is, or the length of the crosslinked body is extended, or a new crosslinked body is attached to a metal body, and the crosslinked body is attached to the outer periphery of the core metal. Alternatively, a method for constructing an immersion pipe, which is characterized in that it is connected and fixed to the lower end.