JP2006312188A - Continuous casting nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous casting nozzle capable of suppressing aluminum sticking onto its inner tube having a discharge hole when continuously casting a steel such as an aluminum killed steel liable to cause the aluminum sticking onto the inner tube. <P>SOLUTION: In this continuous casting nozzle composed of a nozzle body and powder line parts and having the discharge hole, refractories, whose temperature conductivity in the temperature region of ≥500°C is ≤0.01 m<SP>2</SP>/hr, are arranged at least at the working face of the side wall opposite to the discharge hole and the working face of the bottom part of the nozzle inner tube and/or at the inside with a prescribed interval from the working face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nozzle for continuous casting such as a submerged nozzle used in a flow path of molten steel discharged from a container such as a ladle or tundish used for continuous casting in a steelmaking process, and more specifically, alumina adhesion. It is related with the nozzle for continuous casting which can prevent.

  Continuous casting nozzles used in the continuous casting process of steel are used for preventing oxidation of molten steel, controlling molten steel flow, and the like, and have a significant influence on steel quality. The continuous casting nozzle used is affected by the steel type. In particular, when molten steel using aluminum as a deoxidizer is cast, alumina adheres to the inner tube surface of the continuous casting nozzle, causing a nozzle clogging problem. It is known. This problem causes the restriction or stop of operation due to the inability to control the molten steel flow, the life of the nozzle, the steel quality, and the like. In order to solve this problem, the following prior art is disclosed.

  For example, Patent Document 1 discloses a continuous casting nozzle (No. 1) characterized in that, in a nozzle for introducing a molten metal, all or almost all of the peripheral portion thereof is made as a non-fired refractory and the outer peripheral portion is made as a fired refractory. 1)); Nozzle for continuous casting in which the non-fired refractory forming the inner periphery is made of alumina-graphite, zirconia-graphite, magnesia-graphite, fused silica or the like (second item); alumina-graphite In addition, a continuous casting nozzle (Section 3) is disclosed in which an outer peripheral portion is formed of a fired refractory made of zirconia-graphite, magnesia-graphite, fused silica, or the like.

  Patent Document 2 discloses a continuous casting nozzle characterized in that at least an inner surface in contact with molten steel is composed of a sintered body composed of 85 to 97 mol% zirconium oxide and 3 to 15 mol% magnesium oxide. It is disclosed.

  Further, Patent Document 3 discloses a nozzle for continuous casting in which a nozzle inner wall in contact with molten steel is in contact with a zirconium oxide layer and a back surface of the zirconium oxide layer to form a conductive material layer (first term); nozzle 10-50 wt% (mass%) of partially stabilized zirconia powder pulverized after the zirconium oxide layer constituting the inner wall is sintered by adding a stabilizer to the zirconia powder, and zirconia powder and a stabilizer 90-50 Cubic having a sintered body composition of 70 wt% (mass%) or less by mixing and molding at a ratio of wt% (mass%), sintering the molded body, and then heat-treating at a temperature of 500 to 1500 ° C. A continuous casting nozzle that is a zirconium oxide body having a body crystal structure (second term); and a continuous casting nozzle that is carbon or a carbon-containing material (third term) is disclosed.

In Patent Document 4, one or both inner surfaces of an immersion nozzle for continuously injecting molten steel in a tundish into a mold and an intermediate nozzle connected to the upper part of the immersion nozzle are provided with (a) 5% by weight ( free of SiO ₂ of greater than wt%), _Al 2 _{O 3} is 90 wt% (mass%) or more of carbonless high alumina refractory, free of SiO ₂ of greater than (b) 5 wt% (wt%) , A carbonless high-magnesia refractory having an MgO content of 90 wt% (mass%) or more, (c) containing no SiO ₂ exceeding 5 wt% (mass%), and a ZrO ₂ content of 90 wt% (mass%) or more A nozzle for continuous casting made of a refractory material in which one or more of carbonless high zirconia refractories are combined (Claim 1); the refractory material is formed into a cylindrical sleeve, and this sleeve Is Continuous casting nozzle inserted into the inner hole of the immersion nozzle and / or intermediate nozzle (Claim 2); the sleeve is inserted into the nozzle inner hole at a position above the meniscus level of the molten steel in the mold during casting. A casting nozzle (claim 3) is disclosed.

  Further, Patent Document 5 discloses a calcium zirconate having a carbon content of less than 1 wt% (mass%) and a free silica content of less than 1 wt% (mass%), zirconia in which calcium oxide is dissolved, There is disclosed a nozzle characterized in that an inner wall surface is formed of any one of zircon refractories, alumina-zirconia, or magnesia-zircon refractories.

  Patent Document 6 discloses an inner refractory having a thermal conductivity of 1.5 to 4.0 W / m · K disposed on the inner hole side in an immersion nozzle for supplying molten metal into a mold, An immersion nozzle for continuous casting, characterized in that it has a two-layer structure with an outer refractory having a thermal conductivity of 15 to 28 W / m · K disposed outside the inner refractory (Claim 1); A continuous casting immersion nozzle (Claim 2) is disclosed, in which a heat insulating layer composed of a 1 to 6 mm heat insulating fiber layer or a void layer is provided between the inner refractory and the outer refractory.

Japanese Patent Application Laid-Open No. 57-1550 JP-A-62-104654 Patent Claim JP 62-104655 A Patent Claim JP-A-3-243258 Patent Claim JP-A-8-281419 Patent Claim JP 2000-312952 A Patent Claim

  Despite the disclosure of the prior art as described above, problems such as operation limitation or stoppage, nozzle life reduction, and steel quality reduction have not been solved. For example, Patent Document 1 is characterized in that a non-fired refractory is disposed on the inner peripheral portion of a continuous casting nozzle, but because it is a non-fired refractory, it contains volatile matter. Cracks occur in the inner periphery due to sudden temperature rise during use. Furthermore, since the continuous casting nozzle of Patent Document 1 is composed of a fired outer peripheral portion (nozzle body) and an inner peripheral portion made of non-fired refractory, there are many complicated processes for manufacturing the continuous casting nozzle. There is a problem that it takes.

  In addition, Patent Documents 2 and 3 are characterized in that a separately prepared zirconia sintered body is used by being fitted to a nozzle main body part, but it is expensive to manufacture and is a sintered body. Therefore, since it is inferior in spalling resistance and is dense, the thermal conductivity is high and the effect of preventing heat removal cannot be obtained. Further, in Patent Document 4, the carbonless high-alumina refractory has a defect that the sintering proceeds and cracks easily during use. Carbonless high-magnesia refractories also have the disadvantage of being susceptible to thermal spalling due to the high thermal expansion coefficient characteristics of magnesia. Furthermore, in the case of carbonless high zirconia, the zirconia in the working surface part of the nozzle inner tube easily sinters due to the high temperature during use, resulting in a structure gap with the low temperature part that is not sintered. Therefore, it has the disadvantage that the spalling resistance is inferior and the durability is reduced. Further, since Patent Document 5 has a carbon content of less than 1% by mass, when exposed to a high temperature during use, zirconia is rapidly sintered from the working surface side to generate a structure gap. It has the disadvantage that cracks occur during use and the service life is reduced. Furthermore, Patent Document 6 exemplifies alumina, alumina-magnesia, alumina-mullite, and mullite materials as the inner refractory having a thermal conductivity of 1.5 to 4.0 W / m · K. When the continuous casting nozzle is in a steady state, the thermal conductivity is an index for studying suppression of heat removal, lowering of molten steel temperature, etc., but the temperature in the immersion nozzle changes with time In the state, thermal conductivity is not a valid indicator. For this reason, the materials as exemplified cannot sufficiently suppress the adhesion of alumina.

  As described above, according to any of the above patent documents, sufficient durability of the nozzle for continuous casting cannot be obtained, and this causes problems such as operation restriction or stoppage and steel quality degradation to be solved. Not.

  Accordingly, an object of the present invention is to suppress alumina adhesion to the inner pipe of a continuous casting nozzle having a discharge hole when continuously casting a steel type such as aluminum killed steel that is likely to cause alumina adhesion to the continuous casting nozzle. An object of the present invention is to provide a nozzle for continuous casting that can be used.

That is, the continuous casting nozzle of the present invention is composed of a nozzle body and a powder line part, and has a discharge hole, and the working surface of at least the side wall on the side opposite to the discharge hole and the bottom surface of the nozzle inner pipe. And / or a fire-resistant material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is disposed inside the working surface at a predetermined interval.

  In the continuous casting nozzle of the present invention, the nozzle body is composed of an alumina-carbon refractory material composed of 40 to 90% by mass of alumina, 10 to 40% by mass of carbon, and 0 to 30% by mass of silica. Is composed of a zirconia-carbonaceous refractory material composed of 70 to 90% by mass of partially stabilized zirconia and 10 to 30% by mass of carbon.

Further, in the continuous casting nozzle of the present invention, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is formed of an operating surface of at least the side wall of the nozzle inner pipe, It is characterized in that it is disposed at a depth of more than 4% and less than 20% of the nozzle wall thickness of the bottom working surface with a thickness of 5% or more and less than 96% of the nozzle wall thickness.

In the continuous casting nozzle of the present invention, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher has a carbon content of 1% by mass to less than 5% by mass and partially stabilized. It is one or more selected from the group consisting of a zirconia-carbon refractory material comprising more than 95% by mass and not more than 99% by mass of zirconia, a zirconia refractory material without carbon, and a balloon-like alumina refractory material. Features.

Further, in the continuous casting nozzle of the present invention, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is formed of an operating surface of at least the side wall of the nozzle inner pipe, It is arranged on the operating surface of the bottom with a thickness of 4% or more and less than 50% of the nozzle thickness.

In the continuous casting nozzle of the present invention, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher has a carbon content of 1% by mass to less than 5% by mass and partially stabilized. It is characterized by being one or more selected from the group consisting of a zirconia-carbon refractory material consisting of more than 95% by mass and less than 99% by mass of zirconia and zirconia refractory material without carbon.

Further, in the continuous casting nozzle of the present invention, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is composed of at least the working surface of the nozzle inner pipe on the side opposite to the discharge hole side. On the bottom working surface, the thickness is 4% or more and less than 40% of the nozzle wall thickness, and more than 4% of the nozzle wall thickness on the working surface of the nozzle inner pipe on the side opposite to the discharge hole side and the bottom surface, and 80% It is characterized in that it is disposed in a depth of less than 5% and less than 96% of the nozzle thickness.

Further, the continuous casting nozzle of the present invention has a temperature conductivity of 0.01 m ^{2 in} a temperature region of 500 ° C. or higher, which is disposed on at least the working surface of the nozzle inner side wall and the working surface of the bottom portion. Zirconia-carbon refractory material and carbon-free zirconia refractory material comprising a refractory material having a carbon content of 1% by mass or more and less than 5% by mass and a partially stabilized zirconia content of 95% by mass to 99% by mass or less. The inside of the nozzle inner pipe having a depth of more than 4% and less than 80% of the nozzle wall thickness of the working surface on the side wall opposite to the discharge hole and the working surface of the bottom portion of the nozzle inner pipe. The refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more disposed in the carbon is 1% by mass or more and less than 5% by mass and a partially stabilized zirconia amount of more than 95% by mass It is characterized by being one or more selected from the group consisting of zirconia-carbon refractory material composed of 99% by mass or less, zirconia refractory material without carbon, and balloon-like alumina refractory material.

  According to the continuous casting nozzle of the present invention, it is possible to greatly suppress alumina adhesion in the nozzle inner tube, it is possible to greatly improve the life of the nozzle, as a result, it is possible to perform stable continuous casting, Since the alumina adhesion is suppressed, the molten steel flows smoothly in the nozzle, in the tundish, and in the mold, so that there is no slag and powder entrainment, and the steel quality can be improved.

  The present inventors use a submerged nozzle as an example of a continuous casting nozzle having discharge holes, and regarding the rate of temperature rise of the inner pipe working surface of the submerged nozzle in use with respect to the phenomenon of alumina adhesion to the inner pipe working surface. Study was carried out. Usually, the temperature of the inner tube working surface of the immersion nozzle immediately before the start of casting is much lower than the temperature of the molten steel. This is the driving force for alumina adhesion. That is, the molten steel flowing near the inner pipe working surface in the initial stage of casting is cooled in contact with the inner pipe working surface and solidifies. However, since the alumina fine particles originally contained in the steel are present in the molten steel. During the solidification of the molten steel, the alumina fine particles agglomerate to form the nucleus of the alumina adhesion layer. Moreover, the more steel that is solidified, the larger the alumina aggregates that become nuclei. Therefore, the alumina adhesion layer is formed faster and larger on the alumina aggregates that become nuclei.

  Therefore, it is important to suppress solidification of the molten steel in the vicinity of the inner pipe working surface of the immersion nozzle in the early stage of casting in order to suppress alumina adhesion. Therefore, the production | generation of an alumina adhesion layer can be suppressed by raising the temperature of the inner pipe working surface of the immersion nozzle which contacts molten steel rapidly, and making small the temperature difference of molten steel and an inner pipe working surface. Although the temperature rise of the inner pipe working surface is realized by taking heat from the molten steel, it is ideal that the heat from the molten steel is used only for raising the temperature of the inner pipe working surface. However, in practice, the heat from the molten steel is (1) the heat used to increase the internal temperature of the immersion nozzle; (2) the heat radiated to the atmosphere from the outer surface of the immersion nozzle; and (3) the inner tube It is roughly divided into heat used for temperature rise near the operating surface. Therefore, if the refractory material that can reduce the heat consumed in (1) and (2) and increase (3) is distributed at a predetermined position of the continuous casting nozzle, the molten steel and the inner pipe working surface The temperature difference with can be quickly reduced.

Therefore, as a result of further studies, the present inventors have reduced the amount of heat of (1) and (2) by using a refractory material with low temperature conductivity on the inner pipe working surface of the continuous casting nozzle. And, it was found that the amount of heat of (3) can be increased. Patent literature focusing on the thermal conductivity of the refractory material constituting the inner pipe of the continuous casting nozzle and the nozzle body has already been disclosed, but in order to suppress the adhesion of alumina to the inner pipe working surface of the nozzle for continuous casting An important characteristic is temperature conductivity. Here, the temperature conductivity (a) is given by the following equation (1):
a = λ / (c · ρ) (1) Formula where λ represents thermal conductivity; c represents specific heat; and ρ represents specific mass.
As can be seen from the equation (1), the temperature conductivity (a) is obtained from the thermal conductivity (λ), specific heat (c), and specific mass (ρ) of the refractory material constituting the inner pipe working surface of the continuous casting nozzle. This is the value obtained, and the larger the value of the temperature conductivity (a), the faster the temperature change, and the inner pipe working surface of the continuous casting nozzle as shown in Patent Document 6 described above is constituted. The refractory material to be used is different from that specified from the thermal conductivity.

  When the internal temperature of the refractory material constituting the continuous casting nozzle is in a steady state, the thermal conductivity is an effective characteristic value for suppressing alumina adhesion, but in an unsteady state, the thermal conductivity is an effective characteristic value. It becomes. That is, the amount of heat per unit time that the refractory material constituting the inner pipe working surface of the continuous casting nozzle removes heat from the molten steel constitutes the inner pipe working surface of the continuous casting nozzle when the nozzle temperature is in a steady state. Although it shows a strong correlation with the thermal conductivity characteristic value of the refractory material, it shows a strong correlation with the temperature conductivity in an unsteady state. The heat extracted from the molten steel is divided into heat storage inside the continuous casting nozzle and heat radiation to the outside (outside air) of the continuous casting nozzle. Here, when the steady state is reached, there is no heat accumulation inside the continuous casting nozzle, and only heat radiation to the outside of the nozzle (outside air). Moreover, if it is close to a steady state, it may be considered that the heat is almost only released. That is, the specific heat and specific mass data of the refractory material constituting the inner pipe working surface of the continuous casting nozzle related to heat storage can be ignored, and only the thermal conductivity needs to be considered. On the other hand, in the unsteady state, both heat accumulation inside the refractory material and heat radiation outside the nozzle cannot be ignored, so the specific heat, specific mass, and thermal conductivity of the refractory material that constitutes the inner pipe working surface of the nozzle for continuous casting Any of these data cannot be ignored. Therefore, the temperature conductivity obtained from the specific heat, specific mass, and thermal conductivity of the refractory material constituting the inner pipe working surface of the continuous casting nozzle is important. That is, as a characteristic value representing the degree of heat removal from molten steel, depending on whether the internal temperature of the refractory material constituting the inner pipe working surface of the continuous casting nozzle is in a steady state or an unsteady state Effective characteristic values will be different. According to the study by the present inventors, the temperature conductivity becomes an important characteristic because the driving force of alumina adhesion is generated when the casting is in an unsteady state at the initial stage of casting.

  Moreover, the present inventors estimated the inner pipe working surface temperature of the continuous casting nozzle in use, the internal temperature, the amount of heat stored therein, and the amount of heat released from the continuous casting nozzle to the outside air by the following method. This estimation method is based on heat transfer analysis using a finite element method. In the heat transfer analysis, the specific heat, specific mass, and thermal conductivity of the refractory material constituting the inner pipe working surface of the continuous casting nozzle are used as data, and the continuous casting nozzle is divided into many fine elements (sections). The temperature can be calculated at the contact between each element, and as a result, the average temperature of each element can be calculated. Furthermore, this average temperature can be obtained sequentially over time during operation of the continuous casting nozzle. That is, if the average temperature of all elements is obtained in the same way, and this element temperature is known over time, the amount of heat stored in the element by an arbitrary time can be calculated as specific heat data, specific mass, element volume, and arbitrary time. To the next arbitrary time. If the same operation is repeated for all the elements, the amount of heat stored in the continuous casting nozzle is eventually obtained. Next, the heat radiation amount is obtained from the outer surface temperature (surface in contact with the outside air) of the continuous casting nozzle, the outside air temperature, and the like. As described above, the average temperature on the outer surface of each element is known for each element constituting the outer surface, and considering the outer surface of one element, the temperature difference between the average temperature of the outer surface and the outside air temperature The amount of heat released per unit time is determined from the outer surface area of the element and the heat transfer coefficient. Further, for example, when obtaining the heat dissipation amount for one minute, it can be obtained by integrating the heat dissipation amount per unit time as described above over one minute. Similarly, if all the elements constituting the other outer surface are calculated and added together, the amount of heat released is obtained. Here, the heat transfer coefficient is the amount of heat exchanged between the nozzle and the outside air, and is data set when performing heat transfer analysis as a parameter. The accuracy of this parameter affects the overall accuracy of the analysis, but it is reasonable from our study (research for heat transfer coefficient from data such as nozzle temperature, ambient temperature, and molten steel temperature measured with actual equipment). The value is sought and uses that data. In the heat transfer analysis, the temperature conductivity is taken in through data on the heat transfer rate, specific heat and specific mass of the refractory material constituting the inner pipe working surface of the continuous casting nozzle.

  FIG. 1 is a diagram in which an immersion nozzle having a general shape, which is an example of a continuous casting nozzle, is divided into quarters. Here, the immersion nozzle is comprised from the nozzle main body (1) and the powder line part (2). According to the heat transfer analysis using the finite element method, the temperature of the anti-discharge hole side wall operating surface (3) among the inner tube operating surfaces of the submerged nozzle at the initial stage of casting is the discharge hole side wall operating surface (4). It was found that there was a time when the difference between the two became larger than about 1 minute from the start of casting, and the temperature difference at that time exceeded 100 ° C. In particular, the low temperature portion is the portion (B) where the anti-discharge hole side wall working surface (3) and the bottom working surface (5) intersect. That is, it can be estimated that the temperature of this part is the lowest among the inner pipe working surfaces of the submerged nozzle at the initial stage of casting, and that alumina adheres easily. Actually, when the immersion nozzle after being used in an actual furnace is observed, it is observed that a lot of alumina is adhered to the part (B).

As an example, FIG. 2 shows the result of the temperature transition state of the inner pipe working surface of the immersion nozzle in the initial stage of casting obtained by the heat transfer analysis using the finite element method. FIG. 2 shows the temperatures of the discharge hole side part (C) and the counter discharge hole side part (B: the lowest temperature part on the working surface side) shown in FIG. 1 when the immersion nozzle is made of a single material. Is shown. From FIG. 2, in the immersion nozzle made of zirconia (temperature conductivity in the temperature region of 500 ° C. or higher = 0.002 m ² / hour), the temperature difference between the two parts becomes the largest about 160 ° C. after about 30 seconds from the start of casting, With a balloon-like alumina immersion nozzle (temperature conductivity in the temperature range of 500 ° C. or higher = 0.004 m ² / hour), the temperature difference between the two parts becomes the largest at about 200 ° C. after about 20 seconds from the start of casting, and the graphite It can be seen that the temperature is about 190 ° C. after about 1 minute with the immersion nozzle (temperature conductivity in the temperature range of 500 ° C. or higher = 0.11 m ² / hour).

  There is also a large difference in the temperature rise rate of the zirconia immersion nozzle, the balloon-like alumina immersion nozzle, and the graphite immersion nozzle, and the temperatures of both parts of the zirconia immersion nozzle and the balloon-like alumina immersion nozzle are rapidly increasing. On the other hand, the temperature of both parts in the graphite immersion nozzle gradually increased. Thus, it turns out that the rising speed of the working surface temperature in the early stage of casting and the temperature difference in the working surface differ depending on the constituent material of the immersion nozzle. Furthermore, although the temperature difference occurs as described above in the inner pipe operation surface at the initial stage of casting, it can be seen that the temperature difference in the inner pipe operation surface almost disappears as casting progresses. It is understood that it is important to consider.

  The zirconia immersion nozzle, the balloon-like alumina immersion nozzle, and the graphite immersion nozzle are not actually manufactured. If the immersion nozzle is manufactured with zirconia, balloon-like alumina, or graphite, the heat transfer characteristics are as described above. This is a hypothetical result of heat transfer analysis using the finite element method.

Further, by the same method, an alumina immersion nozzle (temperature conductivity in a temperature region of 500 ° C. or higher = 0.02 m ² / hour) or an alumina-graphite immersion nozzle (temperature conductivity in a temperature region of 500 ° C. or higher = Table 1 below shows the results of a heat transfer analysis for 0.05 m ² / hour) and the estimated amount of heat stored in the immersion nozzle and the amount of heat released from the immersion nozzle to the outside air in one minute from the start of casting. .

  From the above results, it was found that there is a slight difference in the amount of stored heat and the amount of heat released depending on the refractory material constituting the immersion nozzle, but this is not a large difference. Therefore, when considering the results shown in FIG. 2 and Table 1, most of the heat taken away from the molten steel at the initial stage of casting is increased in temperature near the working surface in the immersion nozzle made of zirconia and the immersion nozzle made of balloon-like alumina. It can be seen that it is being used. That is, it can be seen that the balloon-shaped alumina immersion nozzle is a refractory material that has a relatively ideal usage of the heat quantities (1) to (3) described above. On the other hand, in the graphite immersion nozzle, it can be seen that the heat taken away from the molten steel is not much used for increasing the operating surface temperature, but rather is used for heat storage inside the nozzle, and is not a desirable fireproof material.

  As described above, as a result of examining the temperature characteristics of the immersion nozzle composed of various refractory materials, the refractory material constituting the inner pipe working surface of the continuous casting nozzle is differentiated by the difference in temperature conductivity. Can do. Among them, materials such as balloon-like alumina are desirable refractory materials from the viewpoint of heat transfer characteristics, but there are difficulties in using them in actual equipment. That is, if balloon-like alumina is distributed on the working surface of the inner tube of the nozzle that is in contact with the vigorously flowing molten steel, the molten steel is easily damaged, and the balloon-like alumina is damaged, and heat transfer of a refractory material such as balloon-like alumina. The characteristics will not be utilized. On the other hand, a refractory material such as zirconia does not receive molten steel wear even if it is disposed on the working surface side of the nozzle inner tube.

In the first embodiment of the present invention, at least 4% and less than 20% of the nozzle wall thickness from the working surface and the working surface of the bottom side wall of the nozzle inner pipe of the continuous casting nozzle. A refractory material having a layer thickness of 5% or more and less than 96% of the nozzle wall thickness and having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more is provided. Here, the side wall opposite to the ejection hole indicates a portion indicated by the region (3) shown in FIG. As shown in FIG. 2, the temperature of the working surface portion (B) of the counter-discharge-hole side wall is considerably lower than the temperature of the working surface portion (C) of the discharge-hole-side sidewall, and the temperature difference is large. Therefore, the temperature conductivity in the temperature region of 500 ° C. or higher is 0.01 m inside at least a predetermined distance from the working surface of the side wall on the side opposite to the discharge hole and the working surface of the bottom of the nozzle inner tube of the nozzle for continuous casting. ^By disposing a refractory material of ² / hour or less, preferably 0.005 m ² / hour or less, the temperature of the part (B) can be quickly raised to reduce the temperature difference, and as a result, alumina adheres. Can be suppressed. Further, even if alumina is temporarily attached, the temperature difference between the parts (B) and (C) on the operating surface is small, so that it adheres relatively uniformly in the circumferential direction within the nozzle inner tube, and the conventional continuous It does not adhere to the working surface of the side wall opposite to the discharge hole like a casting nozzle. That is, the flow of the molten steel flowing in the nozzle inner tube is almost the same as before the alumina adhesion, which means that it works advantageously to realize stable casting. In addition, a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more is disposed inside the working surface of the discharge hole side sidewall and the working surface of the counter discharge hole side sidewall. As a result, the operating surface temperature can be increased more rapidly.

Here, the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher has a nozzle wall thickness of at least the working surface of the side wall of the nozzle inner pipe and the working surface of the bottom portion. It is good to arrange inside 4% and less than 20%, preferably 6 to 10%. When the location of the refractory material is less than 4% of the nozzle wall thickness from the operating surface, even if the refractory material constituting the nozzle body is disposed on the operating surface side, the refractory material is only slightly damaged. , A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is exposed to the working surface. For example, when the refractory material is made of balloon-like alumina, Undesirable to cause rapid molten steel wear damage. On the other hand, when the position of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is 20% or more of the nozzle thickness from the operating surface, it is disposed on the operating surface side. The thickness of the refractory material that constitutes the nozzle body is too thick, and the performance of the refractory material with a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is not exhibited, and alumina adhesion is suppressed. Can not do. Further, the thickness of the inner layer composed of a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is 5% or more and less than 96%, preferably 10% of the nozzle thickness. It is preferably 50% or less and more preferably 20% or more and 40% or less. If the thickness of the inner layer is less than 5% of the nozzle wall thickness, it is too thin, so the heat removed from the molten steel easily escapes to the outside of the inner layer, and further easily from the outer surface of the continuous casting nozzle to the outside air. Because it escapes, it is not preferable. Further, when the thickness of the inner layer becomes 96% or more of the nozzle wall thickness, the inner layer is exposed on the outer surface of the continuous casting nozzle, and the molten steel accumulates in the mold after the initial casting, and the continuous casting nozzle If it is immersed in molten steel, it will be damaged by wear. Further, if the temperature conductivity of the refractory material constituting the inner layer exceeds 0.01 m ² / hour in a temperature region of 500 ° C. or more, the operating surface temperature cannot be rapidly increased, and an alumina adhesion suppressing effect is obtained. It is not preferable because it is not possible.

In the first embodiment of the present invention, as the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more constituting the inner layer, a balloon-like alumina refractory material, zirconia-carbon A quality refractory material, a zirconia refractory material, etc. can be used.

Here, the balloon-like alumina refractory material is an alumina refractory material having an alumina purity of 95% or more using hollow alumina as a part or all of the alumina raw material. The zirconia-carbonaceous refractory material has a carbon content of 1% by mass or more and less than 5% by mass, preferably 1 to 3% by mass, partially stabilized zirconia content of 95% by mass to 99% by mass or less, preferably 97 to 99% by mass. It has the composition of. Here, when the amount of carbon is less than 1% by mass, it is not preferable because the spalling resistance is poor, and when the amount of carbon is 5% by mass or more, it is preferable because the temperature conductivity exceeds 0.01 m ² / sec. Absent. Note that partially stabilized zirconia can use Y ₂ O ₃ , CaO, MgO, or the like as a stabilizer. Furthermore, the zirconia refractory material is a refractory material obtained by adding balloon-like and / or fiber-like zirconia to partially stabilized zirconia grains.

  In the continuous casting nozzle of the present invention, an alumina-carbon refractory material can be used as the refractory material constituting the nozzle body, and a zirconia-carbon refractory material can be used as the refractory material constituting the powder line portion. . The alumina-carbon refractory material is 40 to 90% by mass of alumina, preferably about 50% by mass, 10 to 40% by mass of carbon, preferably about 30% by mass, and 0 to 30% by mass of silica (30% by mass or less). ), Preferably having a composition of about 20% by mass and an apparent porosity of 10 to 30%, preferably about 20%, and a relatively high porosity. The alumina-carbon refractory material can be appropriately mixed with, for example, boron carbide, silicon carbide or the like as an antioxidant within a range of 1 to 5 mass%, preferably 1 to 3 mass%. The zirconia-carbon refractory material has a composition in the range of 70 to 90% by mass, preferably about 80% by mass, and 10 to 30% by mass of carbon, preferably about 20% by mass.

  In addition, the manufacturing method of the nozzle for continuous casting by this invention is not specifically limited, For example, the normal integral molding method can be used. The monolithic molding method means that the inner layer part dough, the main body part dough, and the powder line part dough previously prepared by kneading are loaded into the composite nozzle creation formwork, and then uniaxial press by a conventional method. This is a method of forming a molded body by molding and / or CIP molding. In addition, you may make the boundary part of each material into the blur structure where both mixed. Drying and firing of the molded body can be performed by conventional methods.

  Here, the blur structure is a configuration in which a boundary layer having a thickness of about 1 to 10 mm is provided at a boundary portion of each refractory material. The boundary layer is formed by mixing refractory materials (hereinafter referred to as “boundary material”) that constitute the boundary (a material created by mixing the boundary material is referred to as “boundary layer material”). The mixing method is a method of using a kneaded material of a boundary layer material prepared in advance (for example, prepared by mixing the boundary material at 50:50), or after one of the boundary materials is put into a molding form, It can be created by a method comprising making irregularities about the thickness of the boundary layer and then putting the other boundary material into the mold.

In the second state aspect of the present invention, the working surface of the bottom part of the inner tube of the nozzle for continuous casting and the working surface of at least the side wall on the side opposite to the discharge hole have a thickness of 4% to 50% of the nozzle thickness, A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of at least ° C. is disposed. Here, as shown in FIG. 2, the temperature of the working surface part (B) on the side opposite to the discharge hole side is considerably lower than the temperature of the working surface part (C) on the discharge hole side, and the temperature difference is also large. Therefore, the temperature conductivity in the temperature region of 500 ° C. or more is 0.01 m ² / hour or less, preferably 0, on the bottom working surface of the continuous casting nozzle and at least the working surface of the side wall opposite to the discharge hole. By disposing a refractory material of 0.005 m ² / hour or less, the temperature of the part (B) can be quickly raised to reduce the temperature difference, and as a result, alumina adhesion can be suppressed. Even if alumina is temporarily attached, the temperature difference on the working surface is small, so that it adheres relatively uniformly in the circumferential direction in the nozzle inner tube, and the anti-discharge hole is similar to the conventional continuous casting nozzle. It will not adhere to the working surface of the side wall. That is, the flow of the molten steel flowing in the nozzle inner tube is almost the same as before the alumina adhesion, which means that it works advantageously to realize stable casting. If a fireproof material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is disposed on the working surface of the discharge hole side wall and the working surface of the counter discharge hole side wall, the working surface The temperature can be increased more rapidly. In addition, a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more is disposed only below the position corresponding to the vicinity of the upper portion of the discharge hole on the working surface of the side wall opposite to the discharge hole. Even in this case, the effect of suppressing the adhesion of alumina can be obtained.

In addition, the thickness of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher can be 4% or more and 50% or less, preferably 10 to 30% of the nozzle thickness. If the thickness of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in the temperature range of 500 ° C. or higher is less than 4% of the nozzle wall thickness, the amount of heat extracted from the molten steel is too thin from the working surface to the back Therefore, it is not preferable because a sufficient amount of heat storage cannot be secured in the vicinity of the operating surface, and thus the operating surface temperature cannot be rapidly increased. Further, if the thickness of the refractory material exceeds 50% of the nozzle thickness, a refractory material different from the refractory material of the nozzle body is disposed, which is not preferable because the spalling resistance is poor. Furthermore, when the temperature conductivity in the temperature region of 500 ° C. or higher of the refractory material exceeds 0.01 m ² / hour, the operating surface temperature cannot be rapidly increased, and the alumina adhesion suppressing effect cannot be obtained. It is not preferable.

In the second embodiment of the present invention, a zirconia-carbon refractory material, a zirconia refractory material is used as the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more constituting the working surface. Materials etc. can be used.

Here, the zirconia-carbonaceous refractory material has a carbon amount of 1% by mass or more and less than 5% by mass, preferably 1 to 3% by mass, a partially stabilized zirconia amount of 95% by mass to 99% by mass or less, preferably 97 to 99% by mass. % Composition. Here, when the amount of carbon is less than 1% by mass, it is not preferable because the spalling resistance is poor, and when the amount of carbon is 5% by mass or more, it is preferable because the temperature conductivity exceeds 0.01 m ² / sec. Absent. Note that partially stabilized zirconia can use Y ₂ O ₃ , CaO, MgO, or the like as a stabilizer. Furthermore, the zirconia refractory material is a refractory material obtained by adding balloon-like and / or fiber-like zirconia to partially stabilized zirconia grains.

  In the continuous casting nozzle of the present invention, an alumina-carbon refractory material can be used as the refractory material constituting the nozzle body, and a zirconia-carbon refractory material can be used as the refractory material constituting the powder line portion. . The alumina-carbon refractory material is 40 to 90% by mass of alumina, preferably about 50% by mass, 10 to 40% by mass of carbon, preferably about 30% by mass, and 0 to 30% by mass of silica (30% by mass or less). ), Preferably having a composition of about 20% by mass and an apparent porosity of 10 to 30%, preferably about 20%, and a relatively high porosity. The alumina-carbon refractory material can be appropriately mixed with, for example, boron carbide, silicon carbide or the like as an antioxidant within a range of 1 to 5 mass%, preferably 1 to 3 mass%. The zirconia-carbon refractory material has a composition in the range of 10 to 30% by mass, preferably about 80% by mass, and 10 to 30% by mass of carbon, preferably about 20% by mass.

In addition, the manufacturing method of the nozzle for continuous casting by this invention is not specifically limited, For example, the normal integral molding method can be used. The integral molding method refers to a kneaded refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher, which is disposed on an operating surface previously kneaded and used for a nozzle body. This is a method in which a kneaded material and a kneaded material for a powder line part are loaded into a composite nozzle producing mold, and thereafter a molded body is produced by uniaxial press molding and / or CIP molding by a conventional method. In addition, after only temporarily forming the nozzle main body kneaded material by uniaxial press molding and / or CIP molding, the temperature conductivity in the temperature region of 500 ° C. or higher disposed on the working surface is 0.01 m ² / hour or lower. This is a method in which a kneaded material of a refractory material is loaded on the inner surface side of a temporary molded body of a nozzle body, and a main body is formed by uniaxial press and / or CIP molding to produce a molded body. In addition, you may make the boundary part of each material into the blur structure where both mixed. Drying and firing of the molded body can be performed by conventional methods.

In the third embodiment of the present invention, at least the working surface of the side wall opposite to the discharge hole and the working surface of the bottom portion of the inner tube of the nozzle have a thickness of 4% or more and less than 40% of the nozzle thickness, and at least the inner tube of the nozzle. 500 ° C or more at a thickness of 5% or more and less than 96% of the nozzle wall thickness within a depth of more than 4% and less than 80% of the nozzle wall thickness of the working surface on the side opposite to the discharge hole and the bottom working surface A refractory material having a temperature conductivity in the region of 0.01 m ² / hour or less is provided. Here, as shown in FIG. 2, the temperature of the working surface part (B) of the side wall opposite to the discharge hole is considerably lower than the temperature of the working surface part (C) of the side wall of the discharge hole, and the temperature difference Is also big. Therefore, the temperature conductivity in the temperature region of 500 ° C. or more is 0.01 m ² / hour or less on the working surface of the bottom of the continuous casting nozzle and at least the working surface of the side wall on the side opposite to the discharge hole, preferably 0.01 m ² / hour or less. By disposing a refractory material of 0.005 m ² / hour or less, the temperature of the part (B) can be quickly raised to reduce the temperature difference, and as a result, alumina adhesion can be suppressed. Even if alumina is temporarily attached, the temperature difference on the working surface is small, so that it adheres relatively uniformly in the circumferential direction in the nozzle inner tube, and the anti-discharge hole is similar to the conventional continuous casting nozzle. It will not adhere to the side wall. That is, the flow of the molten steel flowing in the nozzle inner tube is almost the same as before the alumina adhesion, which means that it works advantageously to realize stable casting. If a fireproof material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is disposed on the working surface of the discharge hole side wall and the working surface of the counter discharge hole side wall, the working surface The temperature can be increased more rapidly. In addition, a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more is disposed only below the position corresponding to the vicinity of the upper portion of the discharge hole on the working surface of the side wall opposite to the discharge hole. Even in this case, the effect of suppressing the adhesion of alumina can be obtained.

The thickness of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher, which is disposed on at least the working surface of the side wall of the nozzle inner pipe and the working surface of the bottom, is The nozzle thickness can be 4% or more and 40% or less, preferably 10 to 30%. If the thickness of the refractory material with a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is less than 4% of the nozzle wall thickness, it will be too thin to maintain sufficient strength and easily cause molten steel wear. This is not preferable because it may fall off. Further, when the thickness of the refractory material exceeds 40% of the nozzle thickness, the refractory having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more that constitutes the inner layer portion arranged behind the nozzle is provided. Since a refractory material different from the refractory material constituting the material and the nozzle body is disposed, the spalling resistance is inferior.

Further, the temperature conductivity in a temperature region of 500 ° C. or higher disposed at a predetermined interval from the working surface of the nozzle inner pipe at least on the side opposite to the discharge hole side and the working surface of the bottom is 0.01 m ² / The distribution position of the refractory material below the time is a position exceeding 4% and less than 80% of the nozzle thickness from the working surface of the nozzle inner tube, and preferably 6% or more and 10% or less. When the distribution position is 4% or less of the nozzle wall thickness from the working surface of the nozzle inner tube, the thickness of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more on the working surface side. Is less than 4% of the nozzle wall thickness, which is not preferable for the above reason. Further, when the distribution position is 80% or more of the nozzle wall thickness from the working surface of the nozzle inner tube, the temperature conductivity in the temperature region of 500 ° C. or more is 0.01 m on the working surface side of the nozzle inner tube. ² / hour or less of the refractory material and the refractory material constituting the nozzle body are disposed, and the thickness of the refractory material constituting the nozzle body is increased. Is not preferable because the characteristics of the refractory material of 0.01 m ² / hour or less cannot be utilized, and alumina adhesion to the nozzle inner tube cannot be suppressed. The thickness of the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher disposed inside the nozzle inner tube is preferably 5% or more and less than 96% of the nozzle thickness. Is preferably 10% to 50%, more preferably 20% to 40%. In addition, since the thickness of the refractory material is less than 5%, the heat extracted from the molten steel is easily behind the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher. It is not preferable because it escapes to the nozzle body and easily escapes to the outside air from the outer surface of the continuous casting nozzle. When the thickness of the refractory material is 96% or more of the nozzle wall thickness, the refractory material is exposed on the outer surface of the continuous casting nozzle, and the molten steel accumulates in the mold after the initial casting. When the casting nozzle is immersed in the molten steel, the refractory material with a temperature conductivity of 0.01 m ² / hour or less exposed to the outer surface of the continuous casting nozzle is easily damaged by damage from the molten steel. It is not preferable because it receives it. Furthermore, when the temperature conductivity in the temperature region of 500 ° C. or higher of the refractory material exceeds 0.01 m ² / hour, the operating surface temperature cannot be rapidly increased, and the alumina adhesion suppressing effect cannot be obtained. It is not preferable. A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more disposed on the operating surface and a temperature conductivity in a temperature region of 500 ° C. or more disposed inside. However, in order to obtain a better effect, the fireproof material disposed on the operation surface can be disposed between the fireproof material of 0.01 m ² / hour or less. It is preferable to distribute a refractory material disposed inside the material continuously.

In the third embodiment of the present invention, as the refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more constituting the working surface, zirconia-carbon refractory material, zirconia refractory material Materials etc. can be used. Moreover, as a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more disposed inside, zirconia-carbon refractory material, zirconia refractory material, balloon-like alumina refractory Materials etc. can be used.

Here, the balloon-like alumina refractory material is an alumina refractory material having an alumina purity of 95% or more using hollow alumina as a part or all of the alumina raw material. The zirconia-carbonaceous refractory material has a carbon content of 1% by mass or more and less than 5% by mass, preferably 1 to 3% by mass, partially stabilized zirconia content of 95% by mass to 99% by mass or less, preferably 97 to 99% by mass. It has the composition of. Here, when the amount of carbon is less than 1% by mass, it is not preferable because the spalling resistance is poor, and when the amount of carbon is 5% by mass or more, it is preferable because the temperature conductivity exceeds 0.01 m ² / sec. Absent. Note that partially stabilized zirconia can use Y ₂ O ₃ , CaO, MgO, or the like as a stabilizer. Furthermore, the zirconia refractory material is a refractory material obtained by adding balloon-like and / or fiber-like zirconia to partially stabilized zirconia grains.

  In the continuous casting nozzle of the present invention, an alumina-carbon refractory material can be used as the refractory material constituting the nozzle body, and a zirconia-carbon refractory material can be used as the refractory material constituting the powder line portion. . The alumina-carbon refractory material is 40 to 90% by mass of alumina, preferably about 50% by mass, 10 to 40% by mass of carbon, preferably about 30% by mass, and 0 to 30% by mass of silica (30% by mass or less). ), Preferably having a composition of about 20% by mass and an apparent porosity of 10 to 30%, preferably about 20%, and a relatively high porosity. The alumina-carbon refractory material can be appropriately mixed with, for example, boron carbide, silicon carbide or the like as an antioxidant within a range of 1 to 5 mass%, preferably 1 to 3 mass%. The zirconia-carbon refractory material has a composition in the range of 70 to 90% by mass, preferably about 80% by mass, and 10 to 30% by mass of carbon, preferably about 20% by mass.

In addition, the manufacturing method of the nozzle for continuous casting by this invention is not specifically limited, For example, the normal integral molding method can be used. The monolithic molding method is a kneaded material for the working surface of a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher, which is disposed on a working surface previously kneaded and prepared. In this method, the kneaded dough, the nozzle body kneaded material, and the powder line kneaded material are loaded into a composite nozzle creating mold, and then a molded body is formed by conventional uniaxial press molding and / or CIP molding. is there. In addition, you may make the boundary part of each material into the blur structure where both mixed. Drying and firing of the molded body can be performed by conventional methods.

Example 1
The effect of the nozzle for continuous casting according to the present invention will be shown in Examples.
3A to 3D are diagrams showing distribution patterns of the immersion nozzle of the product of the present invention manufactured in Example 1. FIG. The immersion nozzle shown in FIGS. 3A to 3D has a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or more of the nozzle body (6), the powder line part (7), and the inner layer part. The refractory material (8). Here, the nozzle body (6) is composed of 52% by mass of alumina, 28% by mass of graphite and 20% by mass of fused silica, and is composed of an alumina-graphite refractory material having an apparent porosity of 20%. The powder line part (7) is composed of 85% by mass of calcia-stabilized zirconia (containing 5% by mass of calcia with respect to 100% by mass of zirconia) and zirconia-graphitic refractory material consisting of 15% by mass of scaly graphite. ing.
Further, as the refractory material (8), the balloon-like alumina refractory material used in the products 1 to 4 of the present invention is composed of porous hollow alumina particles having a purity of 99% or more and a bulk specific gravity of 1.2, and an apparent porosity is 80. The balloon-like alumina refractory material used in the products 5 to 8 of the present invention is composed of porous hollow alumina particles having a purity of 99% or more and a bulk specific gravity of 1.5, and an apparent porosity of 70%. The balloon-like alumina refractory material used in the products 9 to 12 of the present invention is made of porous hollow alumina particles having a purity of 99% or more and a bulk specific gravity of 1.4, and an apparent porosity of 75%. The zirconia-graphitic refractory material used in the products 13 to 16 of the present invention is composed of 97% by mass of zirconia and 3% by mass of graphite, and has an apparent porosity of 15%.

  Table 2 also shows the results of applying the obtained immersion nozzle of the present invention to an actual machine. In the actual machine, the immersion nozzle of the product of the present invention and the immersion nozzle of the comparative product [consisting of a nozzle body and a powder line portion, the nozzle body is composed of 52 mass% alumina, 28 mass% graphite and 20 mass% fused silica, and apparent porosity. Is composed of 20% alumina-graphitic refractory material, and the powder line part is composed of 85% by mass of calcia-stabilized zirconia (containing 5% by mass of calcia with respect to 100% by mass of zirconia) and 15% by mass of scaly graphite. -Consisting of graphite refractory material] were used at the same time, and the state of adhesion of alumina and the fluctuation of the molten metal surface in the mold, which is a standard for stable casting, were examined. The obtained results were indexed and evaluated based on a comparative immersion nozzle. That is, the average deposition thickness of alumina was measured, and an index of the average deposition thickness of the immersion nozzle of the present invention product when the immersion nozzle of the comparative product was set to 100 (referred to as alumina deposition index) was obtained. The smaller the alumina adhesion index, the better the less alumina adhesion. In addition, the amount of molten metal surface fluctuation is measured by measuring the variation of the molten metal surface in the mold at the end of casting, indexed with the variation amount of molten metal surface in the mold using the comparative standard immersion nozzle as 100, and used simultaneously. The index of the mold level fluctuation in the mold using the immersion nozzle was obtained. The smaller the mold level in the mold, the more stable and better the casting. The steel used in the actual machine test was an aluminum killed steel having an Al content of 0.02% by mass or more, and a molten steel having a molten steel temperature of 1580 ° C. was used.

Example 2
4 (a) to 4 (d) are diagrams showing distribution patterns of the immersion nozzle of the product of the present invention manufactured in Example 2. FIG. The immersion nozzle shown in FIGS. 4A to 4D has a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more of the nozzle body (6), the powder line part (7) and the working surface. The refractory material (9). Here, the nozzle body (6) is composed of 52% by mass of alumina, 28% by mass of graphite and 20% by mass of fused silica, and is composed of an alumina-graphite refractory material having an apparent porosity of 20%. The powder line part (7) is composed of 85% by mass of calcia-stabilized zirconia (containing 5% by mass of calcia with respect to 100% by mass of zirconia) and zirconia-graphitic refractory material consisting of 15% by mass of scaly graphite. ing.
Further, as the refractory material (9), the zirconia refractory material used in the products 17 to 20 of the present invention comprises calcia-stabilized zirconia particles 80% by mass and porous hollow zirconia particles 20% by mass, and the apparent porosity is 18%. The zirconia refractory material used in the inventive products 21 to 24 is composed of 80% by mass of calcia-stabilized zirconia particles and 20% by mass of porous hollow zirconia particles, and has an apparent porosity of 15%. The zirconia-graphitic refractory material used in the products 25 to 28 of the present invention is composed of 98% by mass of zirconia and 2% by mass of graphite, and has an apparent porosity of 17%.
Table 3 also shows the results of applying the obtained immersion nozzle of the present invention to an actual machine.

Example 3
5 (a) to 5 (d) are diagrams showing distribution patterns of the immersion nozzle of the product of the present invention manufactured in Example 3. FIG. The immersion nozzle shown in FIGS. 5A to 5D has a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or more of the nozzle body (6), the powder line part (7), and the inner layer part. Refractory material (8) and a refractory material (9) having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher on the operating surface. Here, the nozzle body (6) is composed of 52% by mass of alumina, 28% by mass of graphite and 20% by mass of fused silica, and is composed of an alumina-graphite refractory material having an apparent porosity of 20%. The powder line part (7) is composed of 85% by mass of calcia-stabilized zirconia (containing 5% by mass of calcia with respect to 100% by mass of zirconia) and zirconia-graphitic refractory material consisting of 15% by mass of scaly graphite. ing.
Further, as the refractory material (8), the balloon-like alumina refractory material used in the inventive products 29 to 40 is composed of porous hollow alumina particles having a purity of 99% or more and a bulk specific gravity of 1.2, and an apparent porosity of 80. % Refractory material.
Further, as the refractory material (9), the zirconia refractory material used in the inventive products 29 to 32 is composed of 20% by mass of porous hollow zirconia particles and 80% by mass of magnesia-stabilized zirconia particles, and the apparent porosity is 17%. The zirconia refractory material used in the products 33 to 36 of the present invention is a refractory material having 30% by mass of zirconia fiber and 70% by mass of magnesia-stabilized zirconia grains, and an apparent porosity of 20%. The zirconia-graphitic refractory material used in the inventive products 37 to 40 is a refractory material comprising yttria-stabilized zirconia 97 mass% and graphite 3 mass%, and an apparent porosity of 15%.
Table 4 also shows the results of applying the obtained immersion nozzle of the present invention to an actual machine.

  The nozzle for continuous casting of the present invention can be suitably used for an immersion nozzle or the like.

It is 1/4 sectional drawing of an immersion nozzle. It is a graph which shows the temperature change at the time of casting in the predetermined part of an immersion nozzle. It is a figure which shows the material distribution pattern of the immersion nozzle obtained in Example 1. FIG. It is a figure which shows the material distribution pattern of the immersion nozzle obtained in Example 2. FIG. It is a figure which shows the material distribution pattern of the immersion nozzle obtained in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle body 2 Powder line part 3 Anti-discharge-hole side wall working surface 4 Discharge-hole side wall working surface 5 Bottom working surface 6 Nozzle body 7 Powder line part 8 Refractory material 9 Refractory material

Claims (8)

In a continuous casting nozzle composed of a nozzle body and a powder line part and having discharge holes, at least a predetermined distance from the working surface and / or the working surface of the side wall of the nozzle inner pipe on the side opposite to the discharge hole and / or the working surface. A continuous casting nozzle characterized by disposing a refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher in the opened interior.   The nozzle body is composed of an alumina-carbon refractory material composed of 40 to 90% by mass of alumina, 10 to 40% by mass of carbon and 0 to 30% by mass of silica, and the powder line part is 70 to 90% by mass of partially stabilized zirconia. The continuous casting nozzle according to claim 1, further comprising a zirconia-carbon refractory material comprising 10 to 30% by mass of carbon. The refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher is 4% of the nozzle wall thickness of at least the working surface on the side opposite to the discharge hole and the working surface of the bottom of the nozzle inner tube. The nozzle for continuous casting according to claim 1 or 2, wherein the nozzle is disposed at a thickness of more than 5% and less than 96% of the nozzle wall thickness within a depth of more than 20% and less than 20%. A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is from 1% by mass to less than 5% by mass of carbon and from 95% by mass to 99% by mass of partially stabilized zirconia. The continuous casting nozzle according to claim 3, wherein the nozzle is one or more selected from the group consisting of a zirconia-carbon refractory material, a carbon-free zirconia refractory material, and a balloon-like alumina refractory material. A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher has a nozzle wall thickness of 4 on at least the operating surface of the side wall of the nozzle inner pipe and the operating surface of the bottom. The nozzle for continuous casting according to claim 1 or 2, which is disposed with a thickness of not less than 50% and less than 50%. A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature range of 500 ° C. or higher is from 1% by mass to less than 5% by mass of carbon and from 95% by mass to 99% by mass of partially stabilized zirconia. The nozzle for continuous casting according to claim 5, wherein the nozzle is one or more selected from the group consisting of a zirconia-carbon refractory material and a carbon-free zirconia refractory material. A refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher has a nozzle wall thickness of 4 on at least the operating surface of the side wall of the nozzle inner pipe and the operating surface of the bottom. The nozzle thickness is within a depth of more than 4% and less than 80% of the nozzle thickness of the working surface of the nozzle inner pipe at least on the side opposite to the discharge hole side and the working surface of the bottom. The nozzle for continuous casting according to claim 1 or 2, wherein the nozzle is disposed at a thickness of 5% or more and less than 96%. The refractory material having a temperature conductivity of 0.01 m ² / hour or less in a temperature region of 500 ° C. or higher, which is disposed on at least the working surface on the side wall opposite to the discharge port and the working surface of the bottom of the nozzle inner pipe, One or two selected from the group consisting of a zirconia-carbon refractory material and a zirconia refractory material that is carbon-free and a zirconia-carbon refractory material that is comprised of 1% by mass to less than 5% by mass and a partially stabilized zirconia content of 95% by mass to 99% by mass Above, a temperature region of 500 ° C. or more disposed in a depth of more than 4% and less than 80% of the nozzle wall thickness of the working surface of the nozzle inner pipe on the side opposite to the discharge hole and the working surface of the bottom. The refractory material having a temperature conductivity of 0.01 m ² / hour or less is a zirconia having a carbon content of 1% by mass to less than 5% by mass and a partially stabilized zirconia content of 95% by mass to 99% by mass or less. The continuous casting nozzle according to claim 7, wherein the nozzle is one or more selected from the group consisting of a carbonaceous refractory material, a carbon-free zirconia refractory material, and a balloon-like alumina refractory material.

Images