JPS6343191B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for manufacturing various casting nozzles such as long nozzles, immersed nozzles, and sliding nozzles used for various molten metal containers. [Background Art] A molten metal supply section in a continuous casting facility is configured as shown in FIG. That is, a sliding plate formed of an upper plate 10 and a lower plate 11 is provided below the outlet 9 at the lower end of the tundish 8, and a nozzle A for the sliding nozzle is provided between the lower plate 11 and the immersion nozzle 12. can be installed. The nozzle A is made of a refractory material such as firebrick, but it may be damaged by thermal shock when the molten metal 13 passes through the nozzle A, or it may be damaged by the molten metal 13, and the molten metal 13 may If it leaks or spouts out from nozzle A, it may lead to a serious accident.
Conventionally, as shown in FIG. 1, a nozzle A has been created in which a cylindrical metal case 2 is fitted around the outer periphery of a nozzle body 1 made of refractory material, and the nozzle body 1 is reinforced by the case 2. ing. For such nozzle A, nozzle body 1
In order to fix the metal case 2 to the metal case 2 and also to fill the gap between the outer circumference of the nozzle body 1 and the inner circumference of the case 2, the gap between the outer circumference of the nozzle body 1 and the inner circumference of the case 2 is It is necessary to fill the gap with the filling layer 3. Conventionally, it has been common to use castable or mortar as the filling layer 3. However, filling the gap between the outer periphery of the nozzle body 1 and the inner periphery of the case 2 with castable as described above becomes very complicated and takes a long time. That is,
First, add water and knead the castable in a mixer, then insert and set the nozzle body 1 into the case 2, perform centering to align the centers of the case 2 and the nozzle body 1, and then insert the castable into the nozzle. Pour into the gap between the main body 1 and the case 2. Because castable shrinks as it hardens, more castable is added and poured. After pouring the castable in this way, the castable is left to harden for about 24 hours. Next, remove the spilled contamination deposits on the castable,
After filling the castable joints, the entire surface is cleaned and finished. After this, the castable is dried for over 24 hours at a temperature of 60 to 100 degrees Celsius. In this way, when castable is used as the filling layer 3, castable can be used for tasks such as wiping off dirt caused by liquid castable adhering to the outer surface of the case 2, or pouring additional parts after pouring castable. This requires additional work, which complicates the work, and also requires a long time to cure and dry the castable, which increases the manufacturing time. Furthermore, when castable is used as the filling layer 3 in this way, the penetration of moisture from the castable into the nozzle body 1 is completely unavoidable, and the penetration of moisture into the pores of the refractory bricks forming the nozzle body 1 is completely inevitable. This may cause problems such as a decrease in the strength of the nozzle body 1, and furthermore, the castable may react with the components in the refractory, or may react with the alkali content of the castable. Due to large shrinkage during drying, cracks are likely to occur in the castable during curing and drying, and if the molten metal 13 from the inner periphery of the nozzle body 1 passes through the cracks in the nozzle body 1 and reaches the castable, the molten metal 13
case 2 through this castable crack.
There is also a problem that the molten metal 13 in the case 2 may be melted by the heat and the molten metal 13 may spout out. In addition, the castable is relatively dense and has good thermal conductivity, so when the molten metal 13 is repeatedly used to pass through the nozzle A intermittently, the castable is relatively dense and has good thermal conductivity.
is easily cooled, but when the molten metal 13 is passed through the nozzle body 1 intermittently, cooling and heating are repeatedly applied to the nozzle body 1 with large temperature differences. There is also the problem that the nozzle body 1 repeatedly contracts and expands, and cracks are likely to occur in the nozzle body 1. [Object of the Invention] The present invention has been made in view of the above points, and there is no fear that moisture on the refractory nozzle body will be affected by alkali, and the occurrence of cracks can be reduced. It is an object of the present invention to provide a method for manufacturing a casting nozzle that can be manufactured in a short time without complicating the work. [Disclosure of the Invention] The method for manufacturing a casting nozzle according to the present invention includes fitting a metal case 2 around the outer periphery of a nozzle body 1 made of refractory material, and coating the surface with a coating layer 6 made of phenolic resin. Pour the refractory aggregate particles 5 into the gap between the outer periphery of the nozzle body and the inner periphery of the case 2,
This is heated to melt and harden the phenolic resin coating layer 6, and a filling layer 3 of refractory aggregate particles 5 bound by the melted and hardened phenolic resin binder 4 is formed between the outer periphery of the nozzle body 1 and the inside of the case 12. The present invention is characterized in that it fills the gap between the periphery and the periphery, and the present invention will be described in detail below. As the phenolic resin, any of a novolac type phenolic resin, a resol type phenolic resin, and a mixture of a novolac type phenolic resin and a resol type phenolic resin can be used.
This phenolic resin contains silicates such as sodium silicate and potassium silicate, or silicates such as aluminum phosphate and silicon phosphate as vitrifying agents to prevent oxidation of the phenolic resin or its carbide and to improve the medium temperature. It is preferable to mix phosphates so that the coating layer 6 contains these silicates and phosphates. For example, in the case of sodium silicate,
Any of sodium metasilicate, sodium sesquisilicate, and sodium orthosilicate can be used, and can be blended with the phenolic resin in the form of a sodium silicate solution or powdered sodium silicate. Silicates and phosphates can be used singly or in combination. In addition, phenolic resins contain metal non-oxides that melt when heated, such as Al, Mg, Si, etc., to prevent oxidation of phenolic resins or their carbides, and to improve intermediate temperatures.
It is preferable that Ni, Cr, Ti, Nb, and V are blended singly or in combination of two or more, or blended as an alloy. In addition to these additives, other additives can be blended as needed, but the particle size of these additives is preferably 300 μm or less from the standpoint of miscibility. Then, this phenolic resin is coated on the surface of the refractory aggregate particles 5 to form a phenolic resin coating layer 6 as shown in FIG. Coating can be carried out by a dry hot coating method, a cold coating method, a semi-hot coating method, a powder solvent method, or the like. The dry hot coating method uses solid phenolic resin with a coating of 130 to 180%
It is added to and mixed with the refractory aggregate particles 5 heated to ℃, the solid phenolic resin is melted by heating by the refractory aggregate particles 5, and the surface of the refractory aggregate particles is wetted with the molten phenolic resin to form the coating layer 6. It is coated and then cooled while retaining this coating layer to obtain granular and free-flowing resin-coated particles 14. In the cold coating method, the phenolic resin is dissolved in a solvent such as methanol to form a liquid, and this is added to the refractory aggregate particles 5 and mixed, and the resin-coated particles 14 are obtained by volatilizing the solvent. be. In the semi-hot coating method, resin-coated particles 14 are obtained by adding and mixing liquid phenolic resin dissolved in the above-mentioned solvent to refractory aggregate particles 5 heated to 50 to 90°C. In the powder solvent method, the solid phenolic resin is crushed, the crushed resin is added to the refractory aggregate particles 5, a solvent such as methanol is further added, and the mixture is mixed to obtain the resin-coated particles 14. . Although it is possible to obtain resin-coated grains 14 that are granular, free-flowing, and have excellent fluidity using any of the methods described above, the dry hot coating method is preferable in terms of workability and the like. The mixing ratio of the refractory aggregate particles 5 and the phenolic resin varies depending on the required performance, but in general, the mixing ratio of the phenolic resin to 100 parts by weight of the refractory aggregate particles is 2 to 15 parts by weight in terms of resin solid content. Parts by weight are preferred. Further, the amount of silicates, phosphates, and metal non-oxides should be adjusted to 0.01 to 10 parts by weight. Further, during this mixing, a curing agent, various coupling agents such as a silane coupling agent for making the refractory aggregate particles 5 and the phenolic resin compatible, wax, etc. may be added as necessary. For example, the refractory aggregate particles 5 include zirconia, zircon, alumina, mullite, silica, etc., but those rich in SiO ₂ component are preferred here.
For example, it is preferable to use silica sand. In order to improve filling properties, it is preferable that the refractory aggregate particles 5 have a small particle size, with an average particle size (AFS) of 100
It is desirable that the particles be as fine as the above. Then, the resin-coated particles 14 thus formed are used to fill the gap between the nozzle body 1 made of refractory brick and the case 2 made of metal such as steel, as shown in FIG. However, in this work, the nozzle body 1 is first inserted and set into the case 2, and centering is performed to align the centers of the case 2 and the nozzle body 1. Then, the resin-coated particles 14 are poured into the gap between the nozzle body 1 and the case 2, and the gap is filled with the resin-coated particles 14. Since the resin-coated particles 14 have a smooth granular shape, they can be smoothly flowed into the gap between the nozzle body 1 and the case 2 using vibration, and the gap can be easily filled. After filling the gap between the nozzle body 1 and the case 2 with the resin-coated particles 14 in this way, the upper and lower openings of the gap between the nozzle body 1 and the case 2 are sealed with castables, and the resin-coated particles are sealed. Heat drying is performed in a state where the grains 14 are prevented from flowing out. Heating is in an oven at a temperature of about 150 to 300 degrees Celsius.
It is common to do this for about a minute. By heating in this way, the phenolic resin of the coating layer 6 in the resin-coated grains 14 is once melted, and the phenolic resins of the coating layer 6 of adjacent resin-coated grains 14 are welded together, and in this state, the phenolic resin is melted. The resin hardens, and as shown in FIG. 4, the hardened phenolic resin becomes a binder 4 to bind each refractory aggregate grain 5, and the refractory aggregate grains 5 bound by this phenolic resin binder 4 becomes the filling layer 3, and the gap between the nozzle body 1 and the case 2 can be filled with the filling layer 3 as shown in FIG. Thereafter, the entire casting nozzle A can be finished by cleaning the entire casting nozzle A if necessary. In the casting nozzle A manufactured by filling the gap between the nozzle body 1 and the case 2 with the filling layer 3 in which refractory aggregate particles 5 are bound with the phenolic resin binder 4, continuous casting is performed. Flows to nozzle A when used in actual equipment such as equipment
The phenolic resin binder 4 is fired and carbonized by the action of the high temperature of the molten metal 13 of 1500° C. or higher. Nozzle body 1 and nozzle body 1 as described above.
The casting nozzle A can be obtained by filling the gap between the nozzle A and the metal case 2 fitted around the outer periphery of the nozzle A. The resin-coated particles 14 poured into the gap between the main body 1 and the case 2 are granular and fluid in themselves, and there is no need to mix them with water to make them into a liquid. There is no need for the process of adding water in advance and kneading with a mixer, and there is no need for the additional pouring process as with castables, so the work does not become complicated as when using castables. The filling layer 3 can be formed by heating and curing the phenolic resin, and the phenol resin can be cured by heating for a short time without requiring a long period of time to harden and dry as in the case of castable resin. This means that the casting nozzle A can be manufactured using the same method. In addition, there is no influence of moisture or alkali on the refractory nozzle body 1, unlike when using castables, and there is no risk of the strength of the nozzle body 1 being reduced. In addition, a packed layer 3 is formed by bonding the refractory aggregate particles 5 with the phenolic resin binder 4.
Unlike castable, it does not shrink significantly during hardening and drying, and there is no risk of cracks occurring in the filling layer 3. Furthermore, the packed layer 3 has excellent heat insulation properties, and when the nozzle A is repeatedly used in such a manner that the molten metal 13 is passed intermittently, the nozzle body 1 is cooled by the packed layer 3, which has excellent heat insulation properties. Therefore, when the molten metal 13 is passed through the nozzle body 1 intermittently, the nozzle body 1 is not repeatedly cooled and heated due to large temperature differences, and the nozzle body 1 is prevented from being repeatedly cooled and heated. There is no risk of cracks occurring in the nozzle body 1 due to repeated contraction and expansion due to large dimensional differences. In addition, as mentioned above, SiO ₂ is used as the refractory aggregate particles 5.
By using silica sand rich in components, the thermal expansion at medium temperatures (500 to 900°C) in the packed bed 4 can be increased, and when the nozzle A is used for casting, the gap between the nozzle body 1 and the case 2 is always reduced. This means that it can be filled without any gaps. In addition, as mentioned above, by blending silicate and phosphate into the phenolic resin, the silicate and phosphate act as a binder for the glass by firing with the molten metal 13, and the phenolic resin also acts as a binder for the glass. By blending the metal non-oxide, the metal non-oxide acts as an oxide binder by firing with the molten metal 13, and as a result, this glassy binder is bonded to the filling layer by the oxide binder. 4 can be given flexibility,
It is possible to absorb the expansion and contraction of the nozzle body 1 and reduce the stress load on the case 2. Next, the present invention will be specifically explained using examples. Example 1 Average particle size 100 mesh heated to 140°C, SiO ₂
Put 30kg of 98% silica sand into a whirl mixer,
This is a novolak type phenolic resin with a softening point of 90℃.
After adding 2.4Kg (8% by weight of silica sand) and kneading for 30 seconds, 240g of hexamethylenetetramine was added to 300g of hexamethylenetetramine.
g of water was added and kneaded until the sand grains were disintegrated. Next, 15 g of calcium stearate was further added to the mixture, kneaded for 30 seconds, and then discharged to obtain resin-coated granules. Example 2 Resin-coated grains were obtained in the same manner as in Example 1 except that powdered sodium silicate No. 1 containing 4% by weight of silica sand was heated and mixed in advance with the novolak type phenolic resin in Example 1. Example 3 One part of powdered sodium silicate was added to the resin-coated grains obtained in Example 1.
1.5 kg (4% by weight of silica sand) of No. 1 was added and mixed for 30 seconds in a Whirl mixer to obtain resin-coated granules in which powdered silica sand and soda were dispersed. Comparative Examples 1 and 2 The quality of castable used for comparison is
Shown in the table.

[Table] Various tests were conducted on the resin-coated grains obtained in Examples 1 to 3 and the castables in Comparative Examples 1 and 2. The results are shown in Table 2. In Table 2, the melting point (°C) is determined by the JACT test method SM.
-1, room temperature bending strength (Kg/cm ² ) is based on JACT test method C-1, and rapid thermal expansion coefficient (%) is
1000 in _N2 gas according to JACT test method SM-7
Each test was conducted at a measurement temperature of °C. Hot bending strength (Kg/cm ² ) was determined by placing a test piece made according to JACT test method SM-1 into an electric furnace set at 1000°C, and measuring the bending strength at 1000°C after processing for 1 minute. I turned it over and finished it. Oxidation resistance was determined by test pieces (20φ x 50mm) prepared according to JACT test method SM-7, placed in an electric furnace set at 1000℃ for 5 minutes, taken out, cooled, and placed on a vibrating sieve for 1 minute. After vibrating, the weight was measured, and the weight percent of the residue was calculated using the following formula for evaluation. (Weight after treatment/Weight before treatment) × 100 (%) The shrinkage rate of the cured product was 120 × 60 × for Examples 1 to 3 at a mold temperature of 300°C and a baking time of 45 seconds.
After firing a 5 mm shell and releasing it from the mold, immediately fix one longitudinal end of this test piece and attach a micro gauge (1/100 mm) to the end face of the other end.
was applied, the gauge was read at each elapsed time, and the shrinkage rate (%) was evaluated by calculating from the following formula. Shrinkage rate = (measured value / 120) × 100 Castable is poured into a triple mold of 40 × 40 × 150 mm, demolded after 48 hours, and the following formula is calculated from the micro gauge reading in the same manner as above for the longitudinal direction. The shrinkage rate (%) was evaluated by calculation. Shrinkage rate = (measured value/150) x 100 Surface stability was evaluated by exposing a 50 x 100 x 5 mm test piece to 600°C for 5 minutes, taking it out, and visually observing the appearance.

[Table] ◎: Very good, ○: Good

[Table] ◎: Very good, △: Slightly bad.
×: Very poor The results in Table 2 confirm that each Example had a lower shrinkage rate than castable, and also had excellent surface stability and no cracks. In addition, in order to evaluate the workability of Examples 1 to 3 and Comparative Examples 1 and 2, resin-coated particles or castables were poured between the nozzle body and the case in an actual nozzle, and then dried and hardened. I did this. The results are shown in Table 3. In Table 3, filling performance was evaluated by performing a hammering sound test in which castable resin-coated particles were poured into each of 10 nozzles and the case was struck with a hammer. The state after drying and hardening can be visually observed by pouring resin-coated grains or castables between the nozzle body and case, drying and hardening them, then cutting the nozzle case and exposing the filled layer to light. I evaluated it accordingly. The state after firing is determined by opening the nozzle.
After firing at 800° C. for 3 hours, the degree of wobbling of the case was evaluated by confirming it by tapping sound, and further by cutting the case to expose the filled layer and visually observing it. The results in Table 3 confirm that each example is superior to each comparative example using castable in terms of workability, fillability, state after drying and hardening, and state after firing. . [Effects of the Invention] As described above, the method for manufacturing a casting nozzle according to the present invention involves fitting a case around the outer periphery of the nozzle body, and applying refractory aggregate particles whose surface is coated with a coating layer of phenolic resin to the nozzle body. A filling layer of refractory aggregate particles is poured into the gap between the outer periphery and the inner periphery of the case, and the phenolic resin coating layer is melted and hardened by pouring into the gap between the outer periphery and the inner periphery of the case. Since the gap is filled between the outer periphery of the nozzle body and the inner periphery of the case, the work of adding water, kneading, and pouring additional water, which is required when using castables, is no longer necessary, which makes the work more complicated. Furthermore, the filling layer can be formed by heating and curing the phenolic resin, and it does not require a long period of time for curing and drying as in the case of castables. It can be manufactured in a short time without any need for production. In addition, the casting nozzle manufactured in this way does not have the influence of moisture or alkali on the refractory nozzle body, which is the case when castable is used as the filling layer, and there is no risk of reducing the strength of the nozzle body. Moreover, the packed layer formed by bonding refractory aggregate particles with a phenolic resin binder does not shrink significantly during hardening and drying unlike castable, and the packed layer has no There is no risk of cracks occurring.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a casting nozzle, Fig. 2 is a reduced sectional view showing how the casting nozzle is used, and Fig. 3 is an enlarged sectional view of a resin-coated granule in which refractory aggregate granules are coated with a coating layer. , FIG. 4 is an enlarged cross-sectional view of refractory aggregate particles bound by a phenolic resin binder. 1 is the nozzle body, 2 is the case, 3 is the filling layer, 4
is a phenolic resin binder, 5 is a refractory aggregate particle,
6 is a covering layer.

Claims (1)

[Claims] 1. A metal case is fitted around the outer periphery of a nozzle body made of refractory material, and refractory aggregate particles whose surface is covered with a coating layer of phenolic resin are placed in the gap between the outer periphery of the nozzle body and the inner periphery of the case. This is heated to melt and harden the phenolic resin coating layer, and the outer periphery of the nozzle body and the inner periphery of the case are made of a filling layer of refractory aggregate particles bound by the molten and hardened phenolic resin binder. A method for producing a casting nozzle, characterized by filling a gap between the casting nozzles.