JPH04349173A - Molded cylinder for repairing inside of cylindrical refractory - Google Patents

Abstract

PURPOSE:To shorten the time required to allow a worked body to exhibit hardening strength by adding binders consisting of a thermosetting resin and a thermoplastic resin and/or pitch in different blending ratios to a refractory material and molding them in a cylindrical two-layered structure. CONSTITUTION:A material for an inner layer is obtd. by adding 2-10 pts.wt. thermosetting resin (B) having >=100 deg.C curing temp. and 5-15 pts.wt. thermoplastic resin which becomes plastic at 100-200 deg.C and/or pitch (C) to 100 pts.wt. refractory material (A). A material for an outer layer is obtd. by adding 0-3 pts.wt. component B and 8-20 pts.wt. component C to 100 pts.wt. component A. The resulting materials are superposed and molded into a cylinder shape to obtain a molded cylinder for repair.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is used for repairing the inner surface of cylindrical refractories such as molten metal containers, discharge ports in atmospheric furnaces, CAS lances lined with refractory materials such as reflux conduits, and immersion nozzles. It is related to a cylindrical body.

0002

[Prior Art] Regarding the construction method of repair material for cylindrical refractories lined with refractory material, for example, the press-in method (Japanese Patent Publication No. 61
-8124), spraying method (Japanese Unexamined Patent Publication No. 60-24311)
There are publicly known examples such as the following. The press-in method involves press-fitting a slurry repair material into the gap between the cylindrical pipe and the wall of the tapping hole through a number of holes drilled in the cylindrical pipe set in the tapping hole. In addition, the spraying method is a method in which a trowel is attached to the tip of a spray nozzle with a rotating function, and the spray material is applied to the wall of the tapping hole while rotating the trowel, and at the same time, the surface on which the spray material is applied is smoothed using the trowel attached to the tip. It is. Furthermore, Japanese Patent Application Laid-Open No. 61-110711 proposes a method in which a layer of refractory repair material lined with an internal tubular core material is spread and crimped using a roller diameter expanding device.

[0003] Regarding the press-fitting method, the repair material is in the form of a slurry during the press-fitting process, but in order to make the entire repair material into a slurry state, an excessive amount of liquid component is required, and the liquid component remains in the form of a slurry after the repair material has hardened. Since 40 to 70% of it volatilizes, the resulting construction body has the drawback of being extremely porous and having low wear resistance and slag erosion resistance. As for the spraying method, the spraying method itself is carried out by adding a large amount of water, and the action of the trowel only has the effect of smoothing the construction surface, so it also has low wear resistance and slag corrosion resistance. It has the disadvantage of becoming.

[0004]Although all of the above methods are methods for repairing the tap holes in the converter, they have the disadvantage that they cannot be repaired while the converter is in operation. In other words, the discharge port for press-fitting material in the press-in method, and the trowel attached to the tip of the nozzle in the spray method, are both considered to be the core of the invention, but these are used during operations where slag and molten iron are heavily scattered. When inserted into a furnace, slag and other substances adhere to the discharge port and iron, making it impossible to perform its original function. As a countermeasure to this problem, it may be possible to attach a protective cover, but then the original purpose would not be achieved, and as a result, its construction would be limited to periods when the converter is out of service.

Furthermore, the repair method using a roller diameter expanding device disclosed in JP-A-61-110711 requires setting the device inside the tubular core material, resulting in a complicated structure in a very narrow space. Since this requires setting up a device, there is a structural limit to its diameter expansion ratio, and there is a drawback that the thickness of the repair material to be applied is limited. In addition, as the structure of the tubular core material, a structure is disclosed in which a steel plate is wound into a cylindrical shape so that its opposing end surfaces overlap, or a structure in which a band-shaped steel plate is wound helically into a cylindrical shape.

However, with the structure of such a tubular core material, there is no structural problem when the diameter of the entire tubular core material is expanded uniformly, but as in the disclosed roller diameter expanding device, when the diameter of the core material is expanded uniformly, it is difficult to If the diameter is gradually expanded toward the ends, when the diameter of one end of the tubular core material that is in contact with the roller is expanded, the portion of the tubular core material that is not in contact with the rollers will be deformed, and the repair material will deform and take the desired shape. This has the major disadvantage that not only is the repair material not formed properly, but also that the repair material in the unexpanded portion is destroyed in some cases, resulting in a lack of consistency between the repair method and the structure of the repair material.

[0007] A method for solving the problems of the prior art, such as the reduction in wear resistance and slag corrosion resistance caused by press-fitting or spraying of slurry refractory materials, as well as the various structural problems of the construction method using a roller diameter expanding device. This was developed by some of the inventors and filed as a repair method using a new diameter expansion method (
(Japanese Patent Application Laid-Open No. 3-75492). In this method, when repairing a cylindrical refractory, a previously integrally molded thermoplastic hardening cylinder is attached to a cylindrical refractory to be repaired that has a sufficient amount of heat to make the material of the cylinder thermoplastic. Insert it inside,
Next, the diameter of the thermoplastic hardening cylinder is expanded by moving a diameter expansion jig having an inclined squeeze surface that applies sufficient pressure to bring about a shape change in the thermoplastic cylinder, and the cylinder becomes a cylinder. This is a repair method that involves pressing and curing the refractory surface to be repaired.

[0008] Thermoplastic hardening here refers to, for example, the property that a molded product has thermoplasticity in a low temperature range and becomes thermosetting in a high temperature range, that is, as a molded product at a low temperature is heated, it first The property of softening and then hardening as the temperature rises.

[0009]

[Problem to be solved by the invention] JP-A-3-75492
The method of the publication requires the use of a cylinder having thermoplastic hardening properties. Regarding the repair material used in the repair method using a roller diameter expanding device disclosed in JP-A No. 61-110711, the repair material used is ``a material made by kneading a refractory material such as magnesia or dolomite with a binder such as tar, pitch, or resin. '', but there is no explanation about its specific composition. Japanese Unexamined Patent Publication No. 3-75492 discloses a method using a fireproof material, a phenol resin, and pitch. However, this cylindrical body is effective when the construction thickness is relatively thin, but when the construction thickness is thick, the part in contact with the furnace wall immediately softens due to heat received from the repaired wall surface, but the inside part becomes deformable. It was found that it takes time for the material to soften to the point where it takes time, and during that time, the hardening of the outer surface in contact with the furnace wall progresses, resulting in a decrease in adhesion to the furnace wall.

[0010] As a means to eliminate this drawback,
As disclosed in Japanese Patent No. 120265, there is a method of forming two layers by changing the ratio of phenol resin and pitch in the binder. However, when the repair material of this publication is applied to the method of JP-A-3-75492, when the diameter of the repair cylindrical body is expanded by moving a diameter expansion jig having an inclined squeeze surface, the outer layer is heated in a high-temperature furnace. Since it is crimped to the wall, it develops sufficient strength in a short time by curing through pitch and carbonization of the phenolic resin. However, the temperature in the inner layer is low, so it is not expected that strength will be developed immediately due to carbonization.

[0011] If the repair was to be carried out during the suspension period, it would be sufficient for the repair material to exhibit only shape-retaining properties immediately after construction, and it would be sufficient for the repair material to develop strength during the subsequent blowing. If the repair can be done in a short time and from outside the furnace by moving the diameter expanding jig, it will be possible to carry out the repair even during the 20-minute blowing period.In that case, within 10 minutes after construction. Preferably, the strength of the repair body needs to be developed within 5 minutes,
Therefore, the repair material disclosed in Japanese Patent Application Laid-open No. 2-120265 cannot be applied.

0012

[Means for Solving the Problems] As a result of various studies in order to solve this drawback, the present inventors have developed a thermoplastic hardening cylindrical body which has been integrally molded in advance so that the material of the cylindrical body is sufficiently thermoplastic. It is inserted into the inside of the cylindrical refractory to be repaired, which retains heat, and then the thermoplastic material is made into thermoplastic material by moving a diameter expanding jig with an inclined squeeze surface that exerts sufficient pressure to cause a shape change in the thermoplastic cylindrical material. A thermoplastic curable cylindrical body used in a repair method in which the diameter of a curable cylindrical body is expanded and the cylindrical body is pressed and hardened on a cylindrical refractory repair surface, the cylindrical body comprising:
2 to 2 parts by weight of thermosetting resin for inner layer per 100 parts by weight of fireproof material
10 parts by weight, 5 to 1 part of thermoplastic resin and/or pitch
Adding 5 parts by weight, the outer layer is 0 to 3 parts by weight of thermosetting resin,
The present invention was achieved by completing a molded cylindrical body for repairing the inner surface of a cylindrical refractory having a two-layer structure in which 8 to 20 parts by weight of thermoplastic resin and/or pitch was added.

[0013] The repair molded article in the present invention is made of a fireproof material as a main raw material, and a cylindrical 2
It is molded into a layered structure.

[0014] The refractory material is appropriately selected from among basic materials such as magnesia, dolomite, and calcia, neutral materials such as alumina and spinel, and acidic materials such as silica and zircon, depending on the material of the wall surface to be repaired. There are no restrictions as long as you use it. It is also possible to add carbonaceous materials such as graphite and coke, metal powders such as aluminum, silicon, and magnesium, and it is also possible to add various types of fibers such as metal fibers and carbon fibers as necessary. It is.

Among the binders used in the present invention, thermoplastic resins that exhibit plasticity at a temperature of 100 to 200° C. can be used, such as novolac type phenolic resins, petroleum resins, and polyethylene resins. Furthermore, the pitch similarly softens and becomes plastic at a temperature of 100 to 200°C, and either petroleum-based or coal-based pitch can be used. The thermoplastic resin and pitch are added to impart plasticity to the material when heated, and since both the thermoplastic resin and pitch have the same effect, they can be used alone or together. is also possible.

On the other hand, the thermosetting resin may be any resin that hardens through a chemical reaction at a temperature of 100° C. or higher, such as epoxy resin, resol type phenolic resin, furan resin, novolac type phenolic resin added with a curing agent. Resins such as can be used. Particularly preferable thermosetting resins include resol-type phenolic resins and novolak-type phenolic resins with a hardening agent added, but when a novolak-type phenolic resin is used as the thermoplastic resin, novolak-type phenolic resins with a hardening agent added are used. The use of phenolic resins must be avoided.

[0017] In the present invention, the repair molded cylindrical body has a two-layer structure, and the feature is that the blending ratio of the binder used in these two layers is changed. That is, since the inner layer is intended to develop strength at an early stage, the thermosetting resin is 2 to 10 parts by weight and the thermoplastic resin and/or pitch is 5 to 15 parts by weight based on 100 parts by weight of the fireproof material. . If the thermosetting resin is less than 2 parts by weight, sufficient curability cannot be obtained even when heat is applied, and if it exceeds 10 parts by weight, curing progresses too quickly, both of which are not preferred. If the amount of the thermoplastic resin and/or pitch added is less than 5 parts by weight, the initial plasticity of the material will not be sufficiently developed, and if it exceeds 15 parts by weight, the physical properties of the resulting constructed body will deteriorate, so both are preferred. do not have.

Next, the outer layer preferably contains 0 to 3 parts by weight of thermosetting resin and 8 to 20 parts by weight of thermoplastic resin and/or pitch to 100 parts by weight of the refractory material. In cases where a thermosetting resin is not particularly required in the outer layer, the surface of the refractory material to be repaired is at a very high temperature, e.g. 1000°C or higher. This is to progress. However, if more than 3 parts by weight of the thermosetting resin is added, curing proceeds too quickly and adhesiveness deteriorates. If the amount of thermoplastic resin and/or pitch added is less than 8 parts by weight, sufficient plasticity will not be expressed during diameter expansion, and if it exceeds 20 parts by weight, not only will excessive fluidity be exhibited, but the physical properties of the constructed object will also deteriorate. So both are unfavorable.

Particularly preferred combinations of binders for the inner and outer layers include 3 to 7 parts by weight of resol type phenolic resin for the inner layer;
Pitch 3-10 parts by weight, novolac type phenolic resin 2
~7 parts by weight, and the outer layer is made of resol type phenolic resin 0
-3 parts by weight, pitch 4-12 parts by weight, and novolac type phenol resin 3-10 parts by weight. By doing this, even the inner layer will develop strength within about 5 minutes after construction. Furthermore, making the composition of the bonding material similar is effective in preventing peeling between the inner and outer layers and integrating the repair material.

The repair molded cylindrical body of the present invention is usually most easily formed into a cylindrical shape by kneading layered raw materials and then press molding or hand molding. The two layers may be molded separately and superimposed, or the two compositions may be placed in a mold and molded at once, and the molding method is not particularly limited.

[0021]

[Function] In the present invention, the structure of the molded cylindrical body for repair is made of two layers, because when it is inserted inside the refractory material that retains heat and is to be repaired, the inner and outer parts of the molded body for repair are generated. In addition to dealing with temperature differences, this is also to ensure that the repair material has a sufficient thickness. That is, since the pressure applied by the squeeze surface has the effect of accelerating the effect, if the construction thickness is thin, construction is possible even with a single layer structure, but the durability of the resulting construction body is low. In order to ensure durability, it is necessary to increase the construction thickness, but in that case, it is impossible to obtain shape retention only by accelerating hardening with the squeeze surface, and heat curing is particularly important in the inner layer where the temperature is low. It is necessary to add a synthetic resin to promote curing through its chemical reaction. In addition, by using a thermosetting resin such as resol-type phenolic resin for the inner layer, we ensure reaction hardening at 100 to 150°C, and by achieving strength development in a short time, it is possible to Repairs are possible.

[0022]

【Example】

Examples 1 to 2, Comparative Examples 1 to 3 The materials shown in Table 1 were kneaded in a kneader, then hand-molded, and had an inner diameter of 140 mmφ and an outer diameter of 240 mmφ (inner layer 30 mmφ).
A molded cylindrical body for repair having a two-layered cylindrical structure and having a length of 300 mm and an outer layer thickness of 20 mm was obtained. Comparative Example 1 in Table 1 is a material composition of a repair material used for the press-in method, and was kneaded in a kneader to obtain a slurry-like repair material for the press-in method. Comparative Example 2 was a material for a repair material for spraying, and was kneaded using an Einrich mixer. Comparative Example 3 has a material composition of a single-layer repair molded body, and after kneading with a kneader, the inner diameter is 140 mmφ and the outer diameter is 24 mm.
It was molded by hand to have a diameter of 0 mm and a length of 300 mm.

Each of the repair materials of Examples 1 to 2 and Comparative Examples 1 to 3 was tested in a converter having a furnace capacity of 250 tons. Steel tapping hole brick M
gO-C brick. The inner diameter of the sleeve after construction is 190
mmφ, the diameter of the diameter expanding device if using a diameter expanding device with a squeeze surface, the diameter of the pipe with many holes to be set for the press-fitting method, and the setting position of the trowel for the spraying method. Each was set and repaired. The results are also shown in Table 1. In addition, the service life in Table 1 is the number of times of tapping until the tapping time extended by repair is shortened to a certain time.

[0024]

[Table 1]

[0025]

[Effects of the Invention] In all of the examples, good construction bodies were formed regardless of whether during operation (during blowing) or after tapping, and the service life of all of them was 38 channels or more. On the contrary,
In the case of Comparative Example 1, which is a press-fitting method, slag adhered to the set pipe during repair during operation, and the press-fitting device that was supposed to rotate and discharge the repair material did not rotate, making the repair impossible. During the repair work during the suspension period after steel tapping, an apparently good constructed body was formed, but the porosity of the constructed body was large and its service life was as low as 12 channels. In the case of Comparative Example 2, which is a spraying method, during repair during operation, slag adhered to the trowel that was supposed to smooth the workpiece, and the repaired surface after work was extremely uneven, resulting in a low service life of 3 channels. In the case of Comparative Example 2 as well, the repair after tapping could be carried out without any problem, but the construction body was still porous and the service life was 9 channels. Furthermore, in the case of Comparative Example 3 in which a single-layer repair molded body was constructed using a diameter expanding device having the same squeeze surface as in the example, the repair during operation was approximately 1/2 of the predetermined construction thickness. It only sticks to the wall and is 6c
It was durable for h. When repairs were performed after steel tapping, the repair material applied to the top surface fell off after construction, but this is thought to be because the inner layer did not harden due to insufficient heat and shape retention was not achieved. .

[0026] The present invention provides a bonding material most suitable for pressure-hardening a thermoplastic repair material using a diameter expanding jig having a squeeze surface when repairing a cylindrical refractory such as a converter tapping hole. The present invention provides a cylindrical body having a composition, and is an excellent repair material that is simpler and more durable than the various methods conventionally used for such repairs. In the present invention, since the time from the start of repair to the onset of hardening strength of the construction body is extremely short, it is possible to repair during blowing, and it is also possible to repair without stopping operation, which contributes to improving work efficiency. It's a big thing to do.

Claims (1)

[Claims] Claim 1: A previously integrally molded thermoplastic curable cylindrical body is inserted into the inside of a cylindrical refractory to be repaired that has a sufficient amount of heat so that the material of the cylindrical body becomes thermoplastic, and then the thermoplastic Expanding the thermoplastic cylindrical body by moving a diameter expanding jig having an inclined squeeze surface that exerts sufficient pressure to cause a shape change in the exposed cylindrical body, and converting the cylindrical body into a cylindrical refractory repair surface. The thermoplastic curable cylindrical body used in the repair method of press-curing has an inner layer of 2 to 10 parts by weight of thermosetting resin and 5 to 15 parts by weight of thermoplastic resin and/or pitch added to 100 parts by weight of the fireproof material. , the outer layer is made of a thermosetting resin of 0 to 3 parts by weight, and the thermoplastic resin and/or pitch is made of 8 to 3 parts by weight.
A molded cylindrical body for repairing the inner surface of a cylindrical refractory, characterized in that it has a two-layer structure in which 20 parts by weight is added.