JPH0260955B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a molded article for crimping repair used for repairing tubular parts of molten metal containers, such as converter tapping holes, RH and DH dip pipes, and lances;
In particular, the present invention relates to a molded article for hot repair that is suitable for hot construction. [Conventional techniques and their problems] Conventionally, methods for repairing converter tapping holes in tubular parts such as molten metal vessels include crimping repair material to the enlarged hole portion with a stamp, or repairing worn tap holes. A method is used in which a hole is excavated, sleeve bricks are inserted, and the gap between the hole and the furnace wall is filled with repair refractory material by spraying or pouring. In addition, immersion pipes are mainly repaired by inserting the pipe into the damaged part and press-fitting a press-fitting material, or by spraying. However, in any case, the conventional methods are inconvenient for efficient hot repair in accordance with the timing of operation of the converter or ladle. As a method to repair tapping holes in a short time while hot,
For example, as in Japanese Patent Application Laid-Open No. 57-169012, a method has been proposed in which a pipe equipped with a head is inserted into a tapping hole, and repair material is discharged under pressure from the hole in the pipe at the same time as drilling. There is. Repairs to immersion pipes are also carried out using almost the same method. However, the constructed body produced by this method inevitably has a large porosity, which poses a problem in terms of durability, so a method using a molded body is preferable. The present applicant has proposed a method using a molded body in Japanese Patent Application Laid-Open No. 61-41883, but this method is a method for repairing a metal pipe, an expandable material layer, a repair refractory layer, and a thin metal plate. In this method, a refractory structure is attached to the repaired area, and the refractory layer is pressed onto the repaired surface by the expansion of the expandable material layer that receives heat from the furnace wall. However, since this repair method utilizes the pressure bonding force generated by the expansion of the expandable material, it has the disadvantage that the temperature range in which it can be performed is limited. In addition, there is also a mechanical crimping method using an expandable tubular core material, as disclosed in Japanese Patent Application Laid-Open No. 110711/1983. The repair material used in this method must be molded to a predetermined thickness and deform as the tubular core material expands, and the publication does not specifically describe a repair material suitable for this method. The present inventors found that the most suitable repair material for such a repair method was to use phenolic resin and pitch in an appropriate amount, and to conduct a hot repair process that takes advantage of the softening flow of the phenolic resin and pitch caused by heat and the deformation caused by compression. A patent was filed for a molded article for repair (Japanese Patent Application Laid-open No. 311083/1983). However, although this repair molded body is very effective for repairing small parts of general furnace walls, when it was formed into a tube shape and applied to the repair of converter tap holes,
The following problems arose. That is, when the amount of phenolic resin and pitch used is small, cracks occur intensively in one or two to three places when the diameter is expanded by a crimping machine, and there are cases where the product is not integrated even after subsequent heating. In addition, if the amount of phenolic resin and pitch is large, after the diameter expansion crimping process, the part in contact with the furnace wall will begin to harden, but the inside of the repair molding will still maintain its fluidity, so the tubular repair molding will It was also observed that a downward force was exerted on the inside of the upper part of the body due to gravity, causing circumferential cracks to occur inside the repair molded body. [Means for solving the problem] In order to solve the above-mentioned drawbacks, as a result of various studies, the problem was solved by adding metal fiber to the formulation disclosed in JP-A No. 63-311083. It was extremely successful. The repair material applied to this method must be softened and deformed by the furnace heat, deformed as the tubular core expands, and firmly bonded to the furnace wall. Therefore, the present invention uses 0.5 to 5 parts by weight of metal fibers with a diameter of 0.1 to 1 mm and a length of 10 to 40 mm, and a particle size of 0.1 to 100 parts by weight of the refractory aggregate.
It is composed of 3 to 12 parts by weight of a granular phenolic resin of ~1 mm and 5 to 18 parts by weight of granular pitches of 0.1 to 1 mm in diameter, and at least a part of the granular phenolic resin or granular pitches is present in the form of granules in the molded article. This is a molded article for hot repair characterized by: The repair molded article of the present invention is mainly composed of refractory aggregate, metal fibers, granular phenolic resin, and granular pitch, but the refractory aggregate is not particularly limited, but is preferably basic based on the material of the converter. . Furthermore, carbon sources such as graphite and coke can be added, and metal powders such as Al, Si, and Mg can also be added for the purpose of preventing oxidation and improving hot strength. The metal fibers are preferably stainless steel fibers or steel fibers, with a diameter of 0.1 to 1 mm and a length of 10 to 40 mm, that is, an aspect ratio of approximately 10 to 400, in an amount of 0.5 to 5 parts by weight per 100 parts by weight of the refractory aggregate. Added. If the diameter is thinner than 0.1 mm, the length is shorter than 10 mm, or the amount added is less than 0.5 parts by weight, the addition effect will be poor, and if the length is 40 mm or more, uniform kneading will be difficult. If the diameter is thicker than 1 mm, the corrosion resistance of the constructed body will decrease, and if the amount added is 5 parts by weight or more, kneading becomes difficult and corrosion resistance decreases, which is not preferable in either case. JP-A No. 60-86078 attempts to add metal fibers and metal powder to fire-resistant aggregate in spraying materials for hot repairs, but these do not improve the spalling resistance of the sprayed material. The objective is to improve heat transfer and promote the carbonization reaction of the carbonaceous resin, rather than to impart wear resistance or prevent crack growth. Therefore, metal powder may be used, but in the present invention, it must be a metal fiber that satisfies the above conditions. The particle size of the phenolic resin used is 0.1 to 1.
It is sufficient that the phenolic resin is within the range of mm, and both resol type and novolac type phenolic resins can be used, and various modified resins of the above-mentioned phenolic resins can also be used. The amount added is 3 to 12 parts by weight per 100 parts by weight of the refractory aggregate, and if it is less than 3 parts by weight, the strength of the repaired construction will be poor, which is not preferable. Furthermore, addition of 12 parts by weight or more is not preferable because when the repair molded article of the present invention is applied hot, it exhibits excessive fluidity and the efficiency of repairing the target area decreases. Next, as long as the pitch is in the range of 0.1 to 1 mm, either petroleum-based or coal-based pitch can be used. The amount added is 5 to 18 parts by weight per 100 parts by weight of the refractory aggregate, and if it is less than 5 parts by weight, physical properties such as a decrease in apparent porosity when hot pressure is applied are noticeable. is not accepted. Also,
If it is added in an amount of 18 parts by weight or more, the hot shape retention will not be sufficient and the physical properties of the resulting construction product will deteriorate, which is not preferable. Further, the particle size of the phenolic resin and pitch used is 0.1 to 1 mm, but if it is used as a fine powder of 0.1 mm or less, it is not preferable because the shape retention under hot conditions deteriorates. Furthermore, if a phenolic resin or pitch of 1 mm or more is used, if no pressure is applied during construction, the area where the phenolic resin or pitch was present becomes a void, which causes a decline in physical properties. Furthermore, the total amount of phenolic resin and pitch added is
It is necessary that the amount is 22 parts by weight or less per 100 parts by weight. If 22 parts by weight or more is added, the hot shape retention characteristic of the present invention will be lost. The organic solvent used in the production of the molded article may be one that dissolves the phenolic resin used and has a boiling point lower than the softening point of the phenolic resin and pitch, and various alcohols, various ethers, etc. Available for use. The amount used may be adjusted depending on the molding method; for example, in the case of press molding, 2 to 5% is appropriate, and in the case of hand molding, 4 to 8% is appropriate. The reason why the organic solvent is used in this way is to partially dissolve the surface of the phenolic resin added in the form of particles during molding, and to make the resulting repair molded product develop a certain level of strength. Furthermore, the reason for using an organic solvent whose boiling point is lower than the softening point of the phenolic resin and pitch used is to speed up the volatilization of the solvent after molding and to quickly develop strength. Furthermore, by heat treatment after molding, all or most of the organic solvent in the molded product is removed by volatilization.
In this case, it is preferable that the temperature be around the lower softening point of the phenolic resin and the pitch. That is, care is taken to ensure that at least a portion of the granular phenolic resin or granular pitches, preferably a large portion of the granular phenolic resin, is present in the molded article of the present invention in the form of granules as long as the shape retention of the repair molded article is maintained. . If the treatment is carried out at a temperature considerably higher than the softening point, the particles of phenolic resin or pitch will soften and flow in the molded article, forming a continuous phase of phenolic resin and/or pitch, and the molded article having the above structure will not be obtained. This is because the shape retention property under hot conditions is lost, which is undesirable. The molded article for hot repair of the present invention is formed into a tubular shape by kneading the raw materials and then pressing or hand punching.
Press molding is preferable because metal fibers are added. [Function] The molded article for hot repair of the present invention is mainly applied at 600°C, as is the case with ordinary baking repair materials.
During the above-mentioned hot process, the heat retained in the furnace wall causes baking hardening and adhesion to the furnace wall. In this case, the phenolic resin and pitch soften and flow due to heat received from the furnace wall, but in the present invention, at least a portion, preferably a majority, of the phenolic resin and pitch are present in the molded product in the form of particles. Therefore, it softens individually,
Although it flows down between the particles of refractory aggregate, it does not soften and deform when heated only as a repair molded body. However, it exhibits the characteristic of being deformed by slight pressure. This pressurization allows the phenolic resin and pitch to be uniformly dispersed within the repair molded body, forming a strong carbon bond, and also resulting in a constructed body with low porosity and excellent physical properties. In addition, the phenolic resin and pitch extruded from the repair material during pressurization concentrate on the repair material and the surface to be repaired, thereby improving the adhesive strength of the construction body. However, as mentioned above, if the amount of phenolic resin and pitch used is small, when expanding the diameter with a crimping machine, 1
If cracks occur intensively in one or two or three places and do not integrate even with subsequent heating, or if there is a large amount of phenol resin and pitch, the inside of the repair molded product may be damaged after the diameter expansion crimping process. Circumferential cracks may occur. To prevent this, metal fibers are added. The addition of metal fibers prevents the occurrence of any of the above-mentioned cracks, and the amounts of phenolic resin and pitch can be varied over a wide range depending on the type and composition of the refractory material. Furthermore, the addition of metal fibers reduces the risk that the repair molded body will be damaged during transportation. [Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Examples 1 to 4, Comparative Examples 1 to 2 After kneading the formulations shown in Table 1 in a kneader, the inner diameter was 200 mm.
mm, outer diameter 250mm, length 300mm cylindrical shape with pressure 100
Kg/cm ² , and the ethanol used as an organic solvent was evaporated at 30° C. for 10 hours to obtain a repair molded article. A set of five of these repair molded bodies was set in a crimping machine, and a simulated tapping hole (inner diameter 270 mm) with an inner wall temperature of 1000°C was prepared.
The material was charged into a container and crimped at a pressure of 2 Kg/cm ² , and its condition was observed and the physical properties were measured. Examples 1 and 2 are repair materials with low fluidity,
No concentration of cracks was observed during diameter expansion, and the repaired body after construction

[Table] was also integrated. Furthermore, although Examples 3 and 4 were made of highly fluid materials, no cracks in the circumferential direction were observed in the repaired bodies after construction. On the other hand, in Comparative Example 1 in which metal fibers were not added, the cracks caused by the diameter expansion remained in the repaired body after construction and were not integrated. In addition, in the sample of Comparative Example 2, cracks were concentrated in one place during diameter expansion, but because of the high fluidity, they were integrated by pressure bonding. but,
A circumferential crack had formed on the upper side of the repaired body after construction, and the physical properties of that part had deteriorated. Example 5, Comparative Examples 3 and 4 The compositions shown in Table 2 were prepared in the same manner as in Example 1, with an inner diameter of 200 mm, an outer diameter of 250 mm, and a length of
Cylindrical crimped repair moldings of 200 mm and 300 mm were obtained. Set five molded bodies with a length of 300 mm and one molded body with a length of 200 mm (total length 1700 mm) into the crimping machine,
The inner wall of the tapping hole of a 250t converter was repaired by crimping. The inner diameter of the tapping hole before construction was 270 to 280 mm. The repaired body after construction was integrated and in good condition, and was able to withstand 25 tapping cycles.

【table】

[Table] On the other hand, in Comparative Example 3, in which no metal fibers were added, cracks appeared in several places after construction, and the durability was shortened.
It was a low 16 times. This was due to wear and tear on the repair parts due to cracks in several places. In addition, in Comparative Example 4, in which the total amount of granular phenolic resin and granular pitch added was 18% and had good fluidity, no cracks were observed after application, but the service life was only 12 times. Especially the part that became the upper part during repair is 12
There was no residue left after the unrolled steel, and this seems to be due to peeling due to cracks in the circumferential direction. Example 6, Comparative Examples 5 and 6 A cylindrical crimped repair molded article having an inner diameter of 500 mm, an outer diameter of 680 mm, and a height of 300 mm was obtained using the formulations shown in Table 3 in the same manner as in Example 1. RH these three molded bodies.
A crimping machine was used to repair the inner surface of the immersion tube on the processed pipe side. The temperature of the inner surface of the immersion tube during construction was 800 to 1000°C. The results are shown in Table 3 together with the results for the case where steel fibers were not added (Comparative Example 5) and the conventional water-mixed alumina press-in repair material (Comparative Example 6).

〔Effect of the invention〕

As a result of the above-described structure and function, the molded article for hot repair of the present invention has good shape retention in hot conditions, deforms and adheres tightly under slight pressure, and becomes a molded article with low porosity. The metal fibers prevented the occurrence of cracks, significantly increasing durability and shortening construction time. Furthermore, damage during transportation of the molded product was reduced.

Claims (1)

[Claims] 1. Diameter 0.1 to 1 mm for 100 parts by weight of refractory aggregate,
0.5 to 5 parts by weight of metal fibers with a length of 10 to 40 mm and particle size
It is composed of 3 to 12 parts by weight of granular phenolic resin with a particle size of 0.1 to 1 mm and 5 to 18 parts by weight of granular pitches with a particle size of 0.1 to 1 mm, and at least a part of the granular phenolic resin or granular pitches remains granular in the molded article. A molded article for hot repair characterized by the fact that it exists.