JP2012055944A - High-temperature assembly, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-temperature assembly favorable for enhancing sealing property at a boundary region between first and second members that are used in a high-temperature environment, and to provide a method for manufacturing the same.SOLUTION: The high-temperature assembly includes: a first member 1X formed of metal or refractory; a second member 6 formed of metal or refractory, and opposite to the first member; a recessed pool section 1W which is formed in at least any one of the first member 1X and the second member 6 so as to be arranged in a boundary region between the first member 1X and the second member 6; and a heat-resistant ceramic seal section 1R formed by baking a heat-resistant sealant which is filled in the recessed pool section 1W, synthesized by the heat during the use, and subjected to cubic expansion.

Description

  The present invention relates to a high-temperature assembly and a method for producing a high-temperature assembly.

  Gas blowing nozzles that perform gas bubbling by blowing gas into a molten metal such as a molten metal are used. The gas blowing nozzle includes a refractory having a gas passage through which a gas flows and an iron skin surrounding the refractory (Patent Document 1). However, it is required to further improve the sealing performance in the boundary region between the refractory and the iron skin. Furthermore, a molten metal nozzle that allows molten metal such as molten steel to pass therethrough is also provided. The molten metal nozzle has a refractory having a molten metal passage through which the molten metal passes and an iron skin surrounding the refractory. Even in this case, it is required to further improve the sealing performance in the boundary region between the refractory and the iron skin.

JP 2007-262471 A

  The present invention provides a high-temperature assembly and a method for manufacturing a high-temperature assembly that are advantageous for improving the sealing performance in the boundary region between the first member and the second member used in a heated high-temperature environment. .

  A high-temperature assembly according to the present invention includes a first member formed of metal or refractory, a second member formed of metal or refractory facing the first member, a first member, and a second member. A concave pool portion formed in at least one of the first member and the second member so as to be disposed in the boundary region of the first layer, and a heat-resistant sealant that expands in volume by being combined in the concave pool portion and synthesized by heat during use And a heat-resistant ceramic seal part formed by firing.

  The method for producing a high-temperature assembly according to the present invention includes: (1) a first heat-resistant sealant containing a plurality of types of ceramic particles that undergo volume expansion when synthesized, a first member, and a second member. And (2) assembling by assembling at least the first member and the second member in a state where the heat resistant sealant is loaded in the concave pool portion formed in the boundary region between the first member and the second member. A second step of forming the attachment, and (3) in a state in which the heat-resistant sealant is loaded in the concave pool portion formed in the boundary region between the first member and the second member of the assembly. Use a heat-resistant sealant at at least one of the operating temperature of the assembly when in use, the preheating temperature of the assembly before using the assembly, and the heating temperature of the assembly before loading the assembly. Heat and sinter, synthesize multiple types of ceramic particles and expand volume Characterized in that it comprises forming a composite ceramic first member of the assembly body and a third step of sealing the boundary region between the second member.

  The high-temperature assembly according to the present invention includes at least a first member and a second member, and fires a heat-resistant sealant loaded in a concave pool portion formed in a boundary region between the first member and the second member. And a formed heat-resistant ceramic pool portion. During use, preheating, etc., the high temperature assembly is heated to a high temperature region of, for example, 600 to 2000 ° C., particularly 800 to 2000 ° C. For this reason, the heat resistant sealant is heated to a high temperature region for a long time. As described above, an unfired or semi-fired heat-resistant sealant is loaded into the recessed pool portion formed in the boundary region between the first member and the second member. In this state, any one of the operating temperature of the assembly when using the assembly, the preheating temperature of the assembly before using the assembly, and the heating temperature of the assembly before loading the assembly At least one, the heat-resistant sealant is heated and fired. That is, the heat-resistant sealant is heated and fired by using a preheating step or a heating step separately depending on a use temperature when using the assembly or before using the assembly. As a result, the ceramic particles are formed by synthesizing a plurality of types of ceramic particles constituting the heat-resistant sealant, and the heat-resistant ceramic pool portion is formed. As a result, the boundary region between the first member and the second member of the assembly is sealed. In this case, the sealing performance in the boundary region between the first member and the second member can be improved.

  The use temperature of the assembly when using the assembly, the preheating temperature of the assembly before using the assembly, and the heating temperature of the assembly before carrying the assembly are 600 to 2000 ° C., particularly 800 It is a high temperature region of ˜2000 ° C. Therefore, since the heat-resistant sealing agent interposed in the boundary region between the first member and the second member is also heated to a high temperature, the first ceramic particles and the second ceramic particles contained in the heat-resistant sealing agent are more in volume than before the reaction. Forms expanding ceramics (eg mullite, spinel, etc.).

  As described above, according to the present invention, a plurality of types of ceramics constituting the heat-resistant sealant are synthesized to form a synthetic ceramic to form a heat-resistant ceramic pool portion. As a result, the boundary region between the first member and the second member of the high-temperature assembly is sealed. Regarding the firing of the heat resistant seal portion, it may be fired by heating at the temperature at the time of use, or may be separately heated and fired at a stage before use. Heating and baking at the temperature at the time of use is simple because it does not require a separate baking step of heating and baking the heat-resistant seal portion.

FIG. 4 is a cross-sectional view of the tundish upper nozzle according to the first embodiment. FIG. 3 is a cross-sectional view of the vicinity of the heat-resistant ceramic pool portion according to the first embodiment. It is sectional drawing of the tundish upper nozzle which concerns on Embodiment 2. FIG. It is sectional drawing of the tundish upper nozzle which concerns on Embodiment 3. FIG. It is sectional drawing of the tundish upper nozzle which concerns on Embodiment 6. FIG. It is sectional drawing of the tundish upper nozzle which concerns on Embodiment 7. FIG. It is sectional drawing of the blowing plug which concerns on Embodiment 8. FIG. It is sectional drawing of the blowing plug which concerns on Embodiment 8, and is sectional drawing cut | disconnected along the VIII-VIII line of FIG. FIG. 16 is a cross-sectional view of a tundish upper nozzle according to the tenth embodiment. FIG. 20 is a sectional view of a tundish upper nozzle according to the eleventh embodiment. It is a graph which shows the result of a gas leak test concerning a test example. It is a photograph figure which shows the microscope picture of the structure | tissue of a sealing layer in connection with a test example.

The heat resistant ceramic pool portion can be thicker than at least one of the first member and the second member. However, it is not limited to this. According to the present invention, it is preferable that the synthetic ceramic that expands in volume when synthesized is mullite, the first ceramic particles are formed of silica, and the second ceramic particles are formed of alumina. In this case, mullite is synthesized as in the following equation (1).
2SiO ₂ + 3Al ₂ O ₃ → 3Al ₂ O ₃ · 2SiO ₂ (Mullite) (1)
The synthesized mullite (3Al ₂ O ₃ .2SiO ₂ ) expands in volume from before the reaction. In this case, the pores in the heat resistant sealant are easily closed. In this case, considering the formula (1), it is more preferable to contain more alumina (Al ₂ O ₃ ) than silica (SiO ₂ ) by mass ratio. For example, a heat-resistant sealant material can be formed by kneading a material containing silica (SiO ₂ ) and more alumina (Al ₂ O ₃ ) than SiO _{2 with} a dispersion medium such as water. In addition, it is preferable that the synthetic ceramic that expands in volume when synthesized is spinel, the first ceramic particles are made of magnesia, and the second ceramic particles are made of alumina.
In this case, mullite is synthesized as in the following equation (2).
MgO + Al ₂ O ₃ → MgO ・ Al ₂ O ₃ (Spinel) (2)
The volume of the synthesized spinel (MgO.Al ₂ O ₃ ) expands from before the reaction.

  Moreover, it is preferable that the one particle size of the 1st ceramic particle and the 2nd ceramic particle which comprise a heat resistant sealing agent is 30 micrometers or less. In this case, it is preferable that one particle diameter is 30 micrometers or less, 20 micrometers or less, 10 micrometers or less, and 5 micrometers or less. When the particle size is small, the reactivity can be increased. The other particle size of the first ceramic particles and the second ceramic particles is preferably 200 micrometers or less, 100 micrometers or less, 50 micrometers or less, 30 micrometers or less, or 20 micrometers or less. Although the thickness of the seal layer formed of the heat-resistant sealant varies depending on the use, size, and type of the high-temperature assembly, 0.2 to 20 millimeters and 0.2 to 10 millimeters are exemplified.

  The high-temperature assembly according to the present invention is a heat-resistant sealant loaded in a concave pool portion disposed in a boundary region between the first member, the second member, and the first member and the second member. The ceramic pool portion is used, and is used in a high temperature region. The heat-resistant sealant contains a plurality of types of ceramic particles that form a synthetic ceramic that expands in volume when synthesized. Since the volume expands, the sealing performance in the boundary region between the first member and the second member is enhanced. The first member and the second member may be metal or refractory. Accordingly, examples of the combination of the first member and the second member include a combination of a refractory and a metal, a combination of a refractory and a refractory, and a combination of a metal and a metal. Examples of the metal include carbon steel, alloy steel, cast iron, cast steel, titanium, titanium alloy, aluminum, and aluminum alloy. If a metal exists in the combination of the first member and the second member, the heat conduction to the heat-resistant sealant can be enhanced.

  In the heat-resistant sealant before firing, at least one of kyanite and andalusite can be blended as necessary. Kyanite and andalusite are sillimitite minerals. Here, when the ceramic in the heat-resistant sealant before firing is 100%, it is possible to adopt a form in which at least one of kyanite and andalusite is contained by 0.01 to 40% by mass ratio. When heated, each of the kyanite and the andalusite expands, so that the sealability associated with the expansion in the seal layer can be improved. Sillimanite group minerals are believed to decompose by heating to mullite and silica. Since mullite has a lower specific gravity than sillimanite group minerals, it causes volume change (expansion). The larger the kyanite and andalusite particle size, the larger the residual expansion. When the particle size is small, the effect on the residual expansion is hardly obtained.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. The blow nozzle (tundish upper nozzle, high temperature assembly) is equipped on the bottom side of the tundish, which is a molten metal container for holding a high temperature molten metal (for example, molten steel), and has a cylindrical porous fireproof property with gas permeability. An object 1X (one of the first member and the second member) and a metal (iron-based) cylindrical outer skin 6 surrounding the porous refractory 1X (the other of the first member and the second member) ). A ring-shaped gas pool 19 is formed inside the cylindrical porous refractory 1X. A gas introduction pipe 5 is provided as a lower gas introduction passage for supplying the blown gas to the gas pool 19. In the cylindrical porous refractory 1X, a passage 7 for passing a molten metal extending in the vertical direction is formed along the vertical direction. The porous refractory 1X has a large number of communicating pores through which gas can pass, and examples of the material include alumina, magnesia, and zirconia.

  As shown in FIG. 1, a ring-shaped concave pool portion 1 </ b> W around the axis P <b> 1 is formed in a boundary region between the cylindrical porous refractory 1 </ b> X and the cylindrical outer iron skin 6. The concave pool portion 1W is formed in a ring shape so as to go around the upper portion of the outer peripheral portion of the cylindrical porous refractory 1X. At the time of assembly, the unfired heat-resistant sealant is loaded in the concave pool portion 1W. This heat-resistant sealant is fired (synthesized) by heating at the time of preheating, heating before use (carrying in), heating at the time of use, or the like. Thereby, the heat resistant ceramic pool portion 1R is formed in a ring shape around the axis P1. The heat-resistant ceramic pool portion 1R expands as residual expansion in the radial direction and the height direction by firing (synthesis). As a result, the boundary region between the upper part of the cylindrical porous refractory 1X and the upper part 6u of the cylindrical outer iron shell 6 is sealed. In particular, the heat-resistant ceramic pool portion 1R is thicker than the thickness of the outer iron shell 6, and a sufficient amount of residual expansion in the radial direction is ensured. As a result, the boundary region between the upper part of the cylindrical porous refractory 1X and the upper part of the cylindrical outer iron shell 6 can be satisfactorily sealed. As a result, the gas blown into the gas pool 18 or the like is prevented from leaking from the boundary region to the upper end 6up side of the outer iron shell 6. The overall height dimension of the iron skin 6 (assembly) is indicated as HA, the center position of the height dimension is indicated as Hm, and the position 2/3 from the lower end 6d of the height dimension is indicated as Hx. As shown in FIG. 1, the heat-resistant ceramic pool portion 1 </ b> R is positioned above the position Hm in the iron skin 6. Accordingly, the heat-resistant ceramic pool portion 1R is located in the upper portion 6u having a conical shape whose diameter decreases toward the upper end 6up of the iron shell 6. In particular, the heat-resistant ceramic pool portion 1R is preferably positioned above the position Hx in the iron skin 6. This is because it is preferable to improve the sealing property because the iron skin 6 is heated violently from the upper side by the molten metal in the tundish and the upper side of the iron skin 6 is exposed to a high temperature environment. As a result, the gas blown into the gas pool 19 or the like is prevented by the heat-resistant ceramic pool portion 1R from leaking to the upper end 6up side of the outer iron shell 6. In addition, it is thought that the thermal expansion in the radial direction of the iron skin 6 is smaller than the expansion amount in the radial direction of the cylindrical porous refractory 1X.

The heat-resistant sealant before firing forming the heat-resistant ceramic pool portion 1R described above contains alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) as main components (active components). The composition of the heat-resistant sealant preferably contains more alumina (Al ₂ O ₃ ) than silica (SiO ₂ ) by mass ratio. For example, silica (SiO _2), silica (SiO ₂₎ materials containing more alumina (Al ₂ O ₃₎ is used a heat-sealing agent which is kneaded with water (dispersion medium). The dispersion medium may be alcohol. Then, the heat-resistant sealant is loaded into the concave pool portion 1W. When the blowing nozzle is used in such a loaded state, the blowing nozzle is maintained in a high temperature region. In this case, for example, a high-temperature molten metal of about 1400 to 1700 ° C. flows through the passage 7 in the direction of the arrow A1. In this way, when the high-temperature assembly is used, a reaction such as the formula (1) occurs in the sealant by receiving heat from the high-temperature molten metal. Since the iron shell 6 and the refractory 1X have heat transfer properties, they can contribute to the heating of the sealing agent.
2SiO ₂ + 3Al ₂ O ₃ → 3Al ₂ O ₃ · 2SiO ₂ (1)
Thus, mullite (3Al ₂ O ₃ .2SiO ₂ ) is synthesized from 2 mol of SiO ₂ and 3 mol of Al ₂ O ₃ . The synthesized 3Al ₂ O ₃ .2SiO ₂ (mullite) expands in volume from before the reaction. Furthermore, even if the heat-resistant ceramic pool part 1R that has generated mullite is a dense body or has pores, the pores are preferably closed. In this way, mullite (3Al ₂ O ₃ · 2SiO ₂ ) is synthesized by the heat when using the gas blowing nozzle, which is a high-temperature assembly, and the volume expands from before the reaction. It is not necessary to carry out. Here, the smaller the particle size of the silica particles (SiO ₂ ) and the alumina particles (Al ₂ O ₃ ), the easier the synthesis reaction of the formula (1) occurs. For this reason, it is better that the particle diameters of the silica particles (SiO ₂ ) and the alumina particles (Al ₂ O ₃ ) are small. The particle size of the silica particles (SiO ₂ ) and alumina particles (Al ₂ O ₃ ) is preferably 100 micrometers or less, more preferably 30 micrometers or less, 10 micrometers or less, and 3 micrometers or less, and more preferably 1 micrometer. The following are particularly preferred:

According to a certain form, for example, the particle size of silica particles (SiO ₂ ) is 3 micrometers or less or 1 micrometer or less, and the particle diameter of alumina particles (Al ₂ O ₃ ) is packed at a high density. Therefore, it is preferable that the thickness is 75 to 1 micrometer. Here, the composition of the heat-resistant sealant before firing is preferably 5 to 50% by mass of silica (SiO ₂ ) and the balance of alumina (Al ₂ O ₃ ) from the viewpoint of volume expansion. Further, it is more preferable that silica (SiO ₂ ) is 10 to 20% by mass and the remainder is alumina (Al ₂ O ₃ ). The ceramic of the sealant before firing is preferably substantially 95% or more, 98% or more, and 100% of alumina and silica by mass ratio. Therefore, it is considered that the heat-resistant sealant before firing (before the synthesis reaction) should not contain other components such as magnesia and zirconia. Therefore, the ceramic composition of the heat-resistant sealant can be exemplified as follows (a) to (e). However, it is not limited to this.
(A) 70% of alumina particles (Al ₂ O ₃ ) of 75 micrometers or less, 15% of alumina particles (Al ₂ O ₃ ) of 10 micrometers or less, 15 of silica particles (SiO ₂ ) of 1 micrometers or less %.
(B) 70% alumina particles (Al ₂ O ₃ ) of 75 micrometers or less, 15% alumina particles (Al ₂ O ₃ ) of 10 micrometers or less, 15 silica particles (SiO ₂ ) of 3 micrometers or less %.
(C) 70% of alumina particles (Al ₂ O ₃ ) of 100 μm or less, 10% of alumina particles (Al ₂ O ₃ ) of 10 μm or less, and 20 of silica particles (SiO ₂ ) of 3 μm or less %. However, it is not limited to this.
(D) 60% of alumina particles (Al ₂ O ₃ ) of 50 μm or less, 20% of alumina particles (Al ₂ O ₃ ) of 10 μm or less, and 20 of silica particles (SiO ₂ ) of 1 μm or less. %.
(E) 50% of alumina particles (Al ₂ O ₃ ) of 30 μm or less, 10% of alumina particles (Al ₂ O ₃ ) of 10 μm or less, and 40 of silica particles (SiO ₂ ) of 1 μm or less %. % Means mass%. Alumina that has not been synthesized into mullite remains as alumina. Alumina in the seal layer can contribute to improving the heat resistance of the seal layer.

  Next, the flow of gas when the gas blowing nozzle of this embodiment is used in continuous casting will be described. In use, the molten steel, etc. in the tundish transferred from the ladle flows toward the continuous casting machine, but the molten metal is directed downward (in the direction of arrow A1 in FIG. 1) in the passage 7. Flowing. In this case, gas (for example, inert gas such as argon gas) is supplied from the gas source to the gas introduction pipe 5. The gas supplied to the gas supply pipe 5 is supplied to the porous portion of the porous refractory 1X through the gas pool 19, and is blown out from the inner peripheral surface 1Xi into the passage 7 (arrow C1 direction, B1 direction). . This suppresses the adhesion of alumina to the sliding plate, collector nozzle, and immersion nozzle of the tundish sliding nozzle device. In addition, the heat-resistant sealing agent that forms the heat-resistant ceramic pool portion 1R has a composition in which the volume is increased by firing and it is difficult to generate a gap in the boundary region between the outer peripheral portion of the cylindrical porous refractory 1X and the outer iron shell 6. ing. For this reason, even if the temperature becomes high during use, it is difficult for gas to leak out from the boundary region. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

  FIG. 2 shows the vicinity of the heat resistant ceramic pool portion 1R formed by firing (synthesis) of the heat resistant sealant. Here, when the thickness of the outer iron skin 6 is a1, the maximum thickness of the heat-resistant ceramic pool portion 1R is a2, and the height of the heat-resistant ceramic pool portion 1R is b, the sealing performance near the heat-resistant ceramic pool portion 1R is improved. It is preferable that a relationship of a1 <a2 and a relationship of a1 <a2 <b are obtained. However, it is not limited to this. Since a2 <b, the sealing distance (slope side portion 101) of the heat resistant ceramic pool portion 1R is secured as b, and high sealing performance is obtained. In addition, since the cylindrical porous refractory 1X in which the heat resistant ceramic pool portion 1R is formed is a porous material having a large number of pores, the expansion is absorbed by the pores, and the amount of expansion is limited. In this respect, according to the present embodiment, the ring-shaped heat-resistant ceramic pool portion 1R that can form a residual expansion that expands in the radial direction and the height direction by synthesis is formed. It is advantageous.

  On the upper part 6u side of the iron shell 6, the upper part of the cylindrical porous refractory 1X (refractory) has a conical shape, and the thickness in the radial direction (arrow DA direction) decreases toward the upper end 6up side of the iron skin 6. . In this case, if the environmental conditions are severe, the strength of the cylindrical porous refractory 1X is insufficient, and cracks may occur. Therefore, as shown in FIG. 2, the concave pool portion 1W and the heat-resistant ceramic pool portion 1R have a substantially triangular cross section, and face the hypotenuse 101 along the inner wall surface of the iron shell 6 and the cylindrical porous refractory 1X. The upper oblique side 102, the lower oblique side 103 facing the cylindrical porous refractory 1X, and the intersection 104 where the oblique side 102 and the oblique side 103 intersect. As shown in FIG. 2, the length of the hypotenuse part 101 is indicated as K1, the length of the hypotenuse part 102 is indicated as K2, and the length of the hypotenuse part 103 is indicated as K3. The relationship is K2> K3, and the relationship is K2> K1> K3. As a result, the intersecting portion 104 is positioned relatively lower in the heat resistant ceramic pool portion 1R. For this reason, the thickness of the radial direction (arrow DA direction) of the part 1X3 (refer FIG. 2) which faces the hypotenuse part 102 among the cylindrical porous refractories 1X is ensured. Examples are K3 / K2 = 0.8 or less, 0.6 or less, and 0.4 or less. The intersection 104 is preferably rounded. However, when a crack or the like does not become a problem, K2 = K3 and K3> K2 may be set. In some cases, the cross sections of the concave pool portion 1W and the heat-resistant ceramic pool portion 1R may be substantially trapezoidal.

(Embodiment 2)
FIG. 3 shows a second embodiment. This embodiment has basically the same configuration and the same function and effect as the first embodiment. As shown in FIG. 3, the blowing nozzle (tundish upper nozzle, high temperature assembly) is composed of a cylindrical upper porous refractory 1 having gas permeability and an upper porous refractory 1 arranged relatively on the upper side. Also, a cylindrical lower porous refractory 2 having gas permeability disposed relatively below, and a cylindrical dense refractory 3 interposed between the upper porous refractory 1 and the lower porous refractory 2. An upper gas introduction pipe 4 as an upper gas introduction passage for supplying blowing gas to the upper porous refractory 1, and a lower gas introduction pipe 5 as a lower gas introduction passage for supplying blowing gas to the lower porous refractory 2, An outer iron skin 6 having a cylindrical shape that functions as an iron skin as a metal skin that surrounds and holds the outer peripheral surfaces of the upper porous refractory 1, the dense refractory 3 and the lower porous refractory 2; . Thereby, the passage 7 for the molten metal passage extending in the vertical direction is formed. Reference numeral 16 denotes an auxiliary dense refractory laminated above the upper porous refractory 1. A ring-shaped upper gas pool 18 is formed between the cylindrical porous refractory 1 </ b> X and the cylindrical outer iron shell 6. A ring-shaped lower gas pool 19 is formed inside the cylindrical porous refractory 1X. As shown in FIG. 2, the dense refractory 3 is divided into an upper dense refractory 3a and a lower dense refractory 3b. Between the upper dense refractory 3a and the lower dense refractory 3b, a heat-resistant sealing agent is filled to form the seal layer 8. The outer dense surfaces of the upper dense refractory 3a, the lower dense refractory 3b, and the lower porous refractory 2 are provided with an iron skin (inner metal skin) 9 attached by shrink fitting or the like. The iron skin 9 is located on the inner peripheral side of the outer iron skin 6. This part is a double iron skin. A seal layer 17 is interposed between the iron skin 6 (first member) and the iron skin 9 (first member).

  The upper gas introduction pipe 4 is introduced so that the front end portion 4 a faces upward along the outer peripheral portion of the dense refractory 3. The tip portion 4a of the upper gas introduction pipe 4 communicates with the outer peripheral portion 1p of the upper porous refractory 1 through a ring-shaped or cylindrical gas pool 18. The boundary region between the inner peripheral portion of the iron skin 9 and the outer peripheral portion of the dense refractory 3 is filled with the same heat-resistant sealant as the seal layer 8 to form the seal layer 8c, and gas can leak out. There is no such thing. The lower gas introduction pipe 5 is introduced so that the front end portion 5 a is in the horizontal direction, and communicates with the outer peripheral portion 2 p of the lower porous refractory 2 through the ring-shaped gas pool 19. The upper porous refractory 1 and the lower porous refractory 2 preferably have a large number of communicating pores through which gas can permeate and are formed of the same material or a similar material. Examples of the material include alumina, magnesia, and zirconia. The dense refractory 3 and the auxiliary dense refractory 16 are formed of a refractory fired so as to be dense. Unlike a non-fired castable layer, the porosity is extremely low and the gas permeability is low. Small, high density and high strength. That is, the dense refractory 3 has smaller gas permeability than the upper porous refractory 1 and the lower porous refractory 2 and has a denseness.

The heat-resistant sealant before firing for forming the seal layers 8, 8c, 17 contains alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) as main components (active components). The composition of the heat-resistant sealant preferably contains more alumina (Al ₂ O ₃ ) than silica (SiO ₂ ) by mass ratio. For example, silica (SiO _2), silica (SiO ₂₎ more alumina (Al ₂ O ₃₎ material containing used heat sealing agent which is kneaded with water or alcohol. Then, such a heat-resistant sealing agent is applied to a boundary region between the lower surface 3d of the upper dense refractory 3a (first member) and the upper surface 3u of the lower dense refractory 3b (second member). A heat resistant sealant is also loaded into the concave pool portion 1W formed on the outer peripheral portion of the cylindrical porous refractory 1X. Thus, the sealing agent before baking is apply | coated to the said border region. When the blowing nozzle in this state is used, the blowing nozzle is maintained in a high temperature region. In this case, for example, a high temperature molten metal of about 1400 to 1600 ° C. flows through the passage 7 in the direction of the arrow A1. In this way, when the high-temperature assembly is used, a reaction such as the formula (1) occurs in the sealant by receiving heat from the high-temperature molten metal. Since the iron skins 6 and 9 and the refractories 1, 2, 3a, 3b and 16 have heat transfer properties, they can contribute to the heating of the sealing agent.

2SiO ₂ + 3Al ₂ O ₃ → 3Al ₂ O ₃ · 2SiO ₂ (1)
Thus, mullite (3Al ₂ O ₃ .2SiO ₂ ) is synthesized from 2 mol of SiO ₂ and 3 mol of Al ₂ O ₃ . The synthesized 3Al ₂ O ₃ .2SiO ₂ (mullite) expands in volume from before the reaction. In this way, mullite (3Al ₂ O ₃ .2SiO ₂ ) is synthesized by heat during use of the gas blowing nozzle, which is a high-temperature assembly, and the volume expands before the synthesis reaction (firing). The heating process may not be performed separately. Here, the smaller the particle size of the silica particles (SiO ₂ ) and the alumina particles (Al ₂ O ₃ ), the easier the synthesis reaction of the formula (1) occurs. For this reason, it is better that the particle diameters of the silica particles (SiO ₂ ) and the alumina particles (Al ₂ O ₃ ) are small. The particle size of the silica particles (SiO ₂ ) and alumina particles (Al ₂ O ₃ ) is preferably 100 micrometers or less, more preferably 30 micrometers or less, 10 micrometers or less, and 3 micrometers or less, and more preferably 1 micrometer. The following are particularly preferred:

According to a certain form, for example, the particle size of silica particles (SiO ₂ ) is 3 micrometers or less or 1 micrometer or less, and the particle diameter of alumina particles (Al ₂ O ₃ ) is packed at a high density. Therefore, it is preferable that the thickness is 75 to 1 micrometer. Here, the composition of the heat-resistant sealant before firing is preferably 5 to 50% by mass of silica (SiO ₂ ) and the balance of alumina (Al ₂ O ₃ ) from the viewpoint of volume expansion. Further, it is more preferable that silica (SiO ₂ ) is 10 to 20% by mass and the remainder is alumina (Al ₂ O ₃ ). The ceramic of the sealant before firing is preferably substantially 95% or more, 98% or more, and 100% of alumina and silica by mass ratio.

  Next, the flow of gas when the gas blowing nozzle of this embodiment is used in continuous casting will be described. In use, the molten steel, etc. in the tundish transferred from the ladle flows toward the continuous casting machine, but the molten metal is directed downward (in the direction of arrow A1 in FIG. 1) in the passage 7. Flowing. In this case, gas (for example, inert gas such as argon gas) is supplied from the gas source to the upper gas introduction pipe 4 and the lower gas introduction pipe 5. The gas supplied to the upper gas introduction pipe 4 is supplied to the porous portion of the upper porous refractory 1 through the gas pool 18, and is directed from the inner peripheral surface 1i of the upper porous refractory 1 into the passage 7 (arrow B1). Blown in the direction). Thereby, the adhesion of alumina to the upper part of the nozzle is suppressed. The gas supplied to the lower gas supply pipe 5 is supplied to the porous portion of the lower porous refractory 2 via the gas pool 19, and is directed from the inner peripheral surface 2i of the lower porous refractory 2 into the passage 7 (arrow C1). Blown in the direction). This suppresses the adhesion of alumina to the sliding plate, collector nozzle, and immersion nozzle of the tundish sliding nozzle device.

  Now, according to the present embodiment, as shown in FIG. 3, a ring around the axis P <b> 1 is formed in the boundary region between the outer peripheral portion of the cylindrical dense refractory 16 and the inner peripheral portion of the cylindrical outer iron shell 6. A concave pool portion 1W is formed. The concave pool portion 1W is formed in a ring shape so as to make one round on the outer peripheral portion of the cylindrical porous refractory 1X. At the time of assembly, the recessed pool portion 1W is loaded with a heat-resistant sealant. This heat-resistant sealant is baked by heat at the time of use and becomes the heat-resistant ceramic pool portion 1R. The heat resistant ceramic pool portion 1R is thicker than the thickness of the iron skin 6, and is formed in a ring shape around the axis P1. The heat-resistant ceramic pool portion 1R seals the boundary region between the upper part of the cylindrical porous refractory 1X and the upper part of the cylindrical outer iron shell 6. For this reason, it is suppressed that the gas from the gas pool 18 leaks outside from the said boundary area, ie, the upper part of the outer side iron shell 6. FIG. The heat-resistant ceramic pool portion 1R is positioned above the position Hm in the iron skin 6. In particular, the heat-resistant ceramic pool portion 1R is preferably positioned above the position Hx in the iron skin 6. The iron skin 6 is heated violently from the upper side by the hot molten metal held in the tundish. The upper side of the iron skin 6 is exposed to a severe high temperature environment. For this reason, it is because it is preferable to improve sealing performance. The gas from the gas pool 18 is prevented from leaking from the upper part of the outer iron shell 6 to the outside. In some cases, the ceramic pool portion 1R may be located between the position Hx and the position Hm. As shown in FIG. 3, the dense refractory 16 holding the heat-resistant ceramic pool portion 1R is dense and has a very low porosity. For this reason, the amount of expansion in the radial direction of the heat-resistant ceramic pool portion 1R is suppressed from being absorbed by the dense refractory 16 and can contribute to enhancing the sealing performance.

  Unlike the non-fired castable, the dense refractory 3 is formed of a dense fired refractory that has been fired in advance, so that the gas permeability is small, but gas may permeate slightly. That is, a part of the gas supplied to the upper porous refractory 1 may permeate through the upper dense refractory 3a to leak into the lower dense refractory 3b. Similarly, part of the gas supplied to the lower porous refractory 2 may permeate through the lower dense refractory 3b and try to leak into the upper dense refractory 3a. However, according to the present embodiment, the seal layer 8 is interposed in the boundary region between the lower surface 3d of the upper dense refractory 3a and the upper surface 3u of the lower dense refractory 3b. For this reason, the leakage from the upper dense refractory 3a to the lower dense refractory 3b is blocked. In addition, leakage from the lower dense refractory 3b to the upper dense refractory 3a is blocked. Therefore, gas supply to the upper porous refractory 1 and the lower porous refractory 2 can be performed independently.

  In addition, the heat-resistant sealant that forms the seal layer 8 has a composition in which the volume is increased by firing and a gap is hardly generated in the boundary region between the upper dense refractory 3a and the lower dense refractory 3b. For this reason, even if the temperature becomes high during use, it becomes difficult for the gas to leak from the seal layer 8. Further, an iron skin 9 is provided as a metal skin surrounding the outer peripheral surfaces of the upper dense refractory 3a, the lower dense refractory 3b, and the lower porous refractory 2. Since the outer peripheral edge 8p of the seal layer 8 is in contact with the inner peripheral wall of the iron shell 9, gas flows along the outer peripheries of the upper dense refractory 3a, the lower dense refractory 3b, and the lower porous refractory 2. Flow is suppressed. Therefore, it is advantageous to supply the gas to the upper porous refractory 1 and the lower porous refractory 2 more independently. Further, a seal layer 8 c formed of the same heat-resistant sealant as that of the seal layer 8 is inserted between the iron skin 9 and the dense refractory 3 that are in contact with the pipe 4. For this reason, gas cannot leak through the outside of the pipe 4. Therefore, the gas supply to the upper porous refractory 1 and the lower porous refractory 2 can be performed more independently.

Further, according to the present embodiment, since the heat-resistant sealant is filled between the upper dense refractory 3a and the lower dense refractory 3b to form the seal layer 8, the upper porous refractory 1 and the upper dense refractory 3b are formed. A set of upper tiers made of refractory 3a and a set of lower tiers made of lower porous refractory 2 and lower dense refractory 3b can be assembled by bonding with a heat-resistant sealant that forms seal layer 8. . Further, according to the present embodiment, as described above, between the iron skin 6 (one of the first member and the second member) and the iron skin 9 (the other of the first member and the second member). Also, a seal layer 17 formed of a heat-resistant seal is interposed. Silica particles (SiO ₂ ) and alumina particles (Al ₂ O ₃ ), which are contained as active ingredients, are blended in the heat-resistant sealant that forms the seal layer 17. Further, in the boundary region between the lower portion 6d of the outer skin 6 (one of the first member and the second member) and the lower porous refractory 2 (the other of the first member and the second member), the heat-resistant sealant A sealing layer 20 is formed by coating the film. Furthermore, in the boundary region between the inner peripheral portion of the upper portion 6u of the outer iron shell 6 (first member) and the outer peripheral portion of the upper porous refractory 1 (second member), the outer iron shell 6 (first member) Also in the boundary region between the inner peripheral portion of the upper portion 6u and the outer peripheral portion of the auxiliary dense chamber refractory 16 (second member), a seal layer 25 formed by applying a heat-resistant sealant is formed.

And the sealing agent which comprises the heat resistant ceramic pool part 1R and the sealing layers 8, 8c, 17, 20, and 25 is formed with the above-mentioned heat resistant sealing agent. For this reason, since the molten metal such as high-temperature molten steel passes through the passage 7 when the blowing nozzle is used, the heat-resistant ceramic pool portion 1R and the seal layers 8, 8c, 17, and 20 are transferred by heat transfer from the molten metal such as molten steel. 25 are heated to a high temperature. Therefore, the silica particles (SiO ₂ ) and alumina particles (Al ₂ O ₃ ) constituting the sealing agent synthesize mullite and expand. For this reason, the sealing performance in the sealing layers 8, 8c, 17, 20, and 25 described above can be improved. In some cases, the heat-resistant ceramic pool portion 1R and the seal layers 8, 8c, 17, 20, and 25 may be heated to a high temperature by preheating before use or heating before carrying in the assembly. As described above, the seal layers 8, 8 c, 17, 20, and 25 are formed of the heat-resistant sealant according to the present embodiment. At least one of them is formed with the heat-resistant sealant according to the present embodiment, and the rest may be formed with a known sealant (such as mortar). In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

(Embodiment 3)
FIG. 4 shows a third embodiment. This embodiment has basically the same configuration and the same function and effect as the first embodiment. In the embodiment shown in FIG. 3, the dense refractory 3 is divided into an upper dense refractory 3a and a lower dense refractory 3b. And between the upper dense refractory 3a and the lower dense refractory 3b, a heat-resistant sealant that synthesizes mullite is filled to form a seal layer 8 when fired as described above. However, in the present embodiment, as shown in FIG. 4, the dense refractory 3 has a shape in which the upper dense refractory 3 a and the lower dense refractory 3 b according to Embodiment 1 are integrated. The seal layer 8 of the first embodiment is not formed. Also in the present embodiment, the heat-resistant ceramic pool portion 1R and the seal layers 8c, 17, 20, and 25 are formed of a heat-resistant sealant that forms the mullite according to the present embodiment. That is, also in the present embodiment, as shown in FIG. 4, the ring-shaped concave pool portion 1 </ b> W around the axis P <b> 1 is formed in the boundary region between the cylindrical dense refractory 16 and the cylindrical outer iron shell 6. Is formed. The recessed pool portion 1W is formed so as to make one round on the outer peripheral portion of the cylindrical porous refractory 1X. The recessed pool portion 1W is loaded with a heat-resistant sealant during assembly. This heat-resistant sealant is baked by the heat during use, that is, by the heat of the molten metal passing through the passage 7 to become the heat-resistant ceramic pool portion 1R, and expands in the radial direction and the height direction. The heat-resistant ceramic pool portion 1R is thicker than the thickness of the iron shell 6, and is formed in a ring shape around the axis P1.

  As a result, the heat-resistant ceramic pool portion 1 </ b> R expands in the radial direction and the height direction, and seals the boundary region between the outer peripheral portion of the dense refractory 16 and the inner peripheral portion of the cylindrical outer iron shell 6. For this reason, it is suppressed that the gas of the gas pool 18 leaks to the upper end 6up side of the iron skin 6 from the said boundary area | region. As shown in FIG. 4, the heat resistant ceramic pool portion 1 </ b> R is positioned above the position Hm in the iron skin 6. In particular, the heat-resistant ceramic pool portion 1R is preferably positioned above the position Hx in the iron skin 6. This is because the upper surface of the iron skin 6 is exposed to a high-temperature environment because the iron skin 6 is heated violently from the upper side thereof, so that it is preferable to improve the sealing performance. As shown in FIG. 4, the outer peripheral part of the dense refractory 16 and the inner peripheral part of the cylindrical outer iron shell 6 have a conical shape with a diameter decreasing toward the upper part. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

(Embodiment 4)
Since the fourth embodiment has basically the same configuration and the same operation and effect as the first to third embodiments, FIGS. 1 to 4 are applied mutatis mutandis. When the ceramics in the heat-resistant sealant before firing forming the heat-resistant ceramic pool portion 1R and the like is 100%, the silica particles (SiO ₂ ) are 0.1 to 30% by mass ratio, and the alumina particles (Al ₂ O ₃ ). Is contained in an amount of 0.1 to 20% (0.1 to 10%, 0.1 to 50%) of one or both of andalusite and kyanite. When heated, andalusite and kyanite (also referred to as kyanite) are aluminum silicates (Al ₂ SiO ₅ ), and when heated, they expand and thus expand during use, further improving sealability. be able to. The particle size of the particles of andalusite or kyanite can be selected as necessary, and examples thereof include 1 to 1000 micrometers, 1 to 100 micrometers, and 5 to 50 micrometers, but are not limited thereto. The larger the kyanite and andalusite particle size, the larger the residual expansion. When the particle size is small, the effect on the residual expansion is hardly obtained. In some cases, the blending ratio of the andalusite and / or kyanite particles may be 1 to 30% by mass ratio. If the particles of andalusite or kyanite are excessive, it is difficult to obtain a homogeneous structure. In addition, when the addition amount of an andalusite or a kyanite is increased, the residual line change rate is increased after firing and the expansion is considered to continue. However, when the addition amount of andalusite or kyanite is excessively large, the residual expansion becomes too large, and the expansion continues and the structure becomes brittle, which may cause peeling.

(Embodiment 5)
Since the fifth embodiment basically has the same configuration and the same function and effect as the first to third embodiments, FIGS. 1 to 4 are applied mutatis mutandis. However, the following points are different. In this embodiment, the ceramic that expands in volume when it is synthesized by a heat-resistant sealant that forms the heat-resistant ceramic pool portion 1R or the like is spinel. Therefore, in the heat resistant sealant, the first ceramic particles are formed of magnesia, and the second ceramic particles are formed of alumina. The heat-resistant sealant contains alumina (Al ₂ O ₃ ) and magnesia (MgO) as main components (active ingredients). The ceramic composition of the heat-resistant sealant preferably contains more alumina (Al ₂ O ₃ ) than magnesia (MgO) by mass ratio. For example, it is preferable to use a heat-resistant sealant obtained by kneading a material containing magnesia (MgO) and more alumina (Al ₂ O ₃ ) than silica (SiO ₂ ) with water. Then, such a heat-resistant sealing agent is applied to a boundary region between the lower surface 3d of the upper dense refractory 3a (first member) and the upper surface 3u of the lower dense refractory 3b (second member). Thus, the sealing agent before baking is apply | coated to the said border region. When the blowing nozzle in this state is used, the blowing nozzle is maintained in a high temperature region. In this case, for example, a high temperature molten metal of about 1400 to 1650 ° C. flows through the passage 7 in the direction of the arrow A1. Reaction as shown in the formula (2) occurs in the sealant by receiving heat from the molten metal.

MgO + Al ₂ O ₃ → MgO ・ Al ₂ O ₃ (2)
One mole of MgO and one mole of Al ₂ O ₃ are fired to synthesize spinel. Spinel (MgO.Al ₂ O ₃ ) expands in volume from before the reaction. Expansion remains as residual expansion. As described above, the spinel is synthesized at the time of use due to the heat at the time of using the gas blowing nozzle which is a high-temperature assembly, and the volume expands from before the reaction. Therefore, it is not necessary to separately perform the heating step (synthesis step). . Here, the smaller the particle size of the magnesia particles (MgO) and the alumina particles (Al ₂ O ₃ ), the easier the synthesis reaction of the formula (2) occurs. For this reason, it is better that the magnesia particles (MgO) and the alumina particles (Al ₂ O ₃ ) have smaller particle sizes. The particle size of the magnesia particles (MgO) and the alumina particles (Al ₂ O ₃ ) is preferably 100 micrometers or less, more preferably 50 micrometers or less, 10 micrometers or less, and particularly preferably 1 micrometers or less.

According to an embodiment, for example, the particle size of the magnesia particles (MgO) is 1 micrometer or less, and the particle size of the alumina particles (Al ₂ O ₃ ) is considered to be packed at a high density. However, it is preferably 75 to 1 micrometer. Here, the ceramics in the heat-resistant sealant before firing is preferably substantially 95% or more, 98% or more, and 100% for alumina and silica. As for ceramics in the heat-resistant sealant before firing, it is preferable in terms of volume expansion that magnesia (MgO) is 1 to 50% by mass and the balance is alumina (Al ₂ O ₃ ). Further, it is more preferable that magnesia (MgO) is 1 to 20% by mass and the remainder is alumina (Al ₂ O ₃ ). The following forms (a) to (c) can be adopted.
(A) 70% of alumina particles (Al ₂ O ₃ ) of 75 micrometers or less, 15% of alumina particles (Al ₂ O ₃ ) of 10 micrometers or less, 15% of magnesia particles (MgO) of 1 micrometers or less Can be blended.
(B) 70% of alumina particles (Al ₂ O ₃ ) of 75 micrometers or less, 15% of alumina particles (Al ₂ O ₃ ) of 10 micrometers or less, 15% of magnesia particles (MgO) of 3 micrometers or less Can be blended.
(C) 70% of alumina particles (Al ₂ O ₃ ) of 100 micrometers or less, 10% of alumina particles (Al ₂ O ₃ ) of 10 micrometers or less, 20% of magnesia particles (MgO) of 3 micrometers or less Can be blended. However, it is not limited to this. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

(Embodiment 6)
FIG. 5 shows a sixth embodiment. The present embodiment has basically the same configuration and the same function and effect as the above-described embodiment. Also in the present embodiment, as shown in FIG. 5, in the boundary region between the outer peripheral portion of the cylindrical dense refractory 16 and the inner peripheral portion of the cylindrical outer iron shell 6, a ring shape around the axis P <b> 1 is formed. A recessed pool portion 1W is formed. The concave pool portion 1W is formed so as to make one round on the outer peripheral portion of the conical shape of the dense refractory 16 (cone whose diameter decreases toward the top). The upper part of the iron skin 6 is formed in a conical shape so as to decrease in diameter toward the upper end thereof. Here, the cone shape means a cone whose diameter decreases toward the top. At the time of assembly, the recessed pool portion 1W is loaded with a heat-resistant sealant. This heat-resistant sealant is baked and expanded by the heat during use, that is, by the heat of the molten metal passing through the passage 7 to form the heat-resistant ceramic pool portion 1R. The heat-resistant ceramic pool portion 1R is formed in a ring shape around the axis P1. The heat resistant ceramic pool portion 1R is formed of mullite or spinel that expands when synthesized, and forms a boundary region between the conical upper portion of the dense refractory 16 and the conical upper portion of the cylindrical outer iron shell 6. It is sealed. As shown in FIG. 5, the dense refractory 16 that holds the heat-resistant ceramic pool portion 1R is dense and has a porosity that is extremely smaller than that of the porous refractory. For this reason, the amount of expansion in the radial direction of the heat-resistant ceramic pool portion 1 </ b> R is suppressed from being absorbed by the dense refractory 16. Therefore, it can contribute to improving sealing performance.

  As shown in FIG. 5, the dense refractory 3 is divided into an upper dense refractory 3a and a lower dense refractory 3b. And between the upper dense refractory 3a and the lower dense refractory 3b, a heat-resistant sealant that synthesizes mullite is filled to form a seal layer 8 when fired as described above. Further, as shown in FIG. 5, a ring-shaped concave pool portion 3W is formed around the axis P1 in the boundary region between the upper dense refractory 3a and the lower dense refractory 3b. At the time of assembly, the recessed pool portion 3W is loaded with a heat-resistant sealant. The loaded heat-resistant sealant is fired (synthesized) as mullite or spinel by heat during use and expands in the radial direction and the height direction to form the heat-resistant ceramic pool portion 3R. This expansion will remain as a residual expansion thereafter. As a result, a biasing force FA (see FIG. 5) is generated toward the upper end 6up of the upper part 6u of the outer iron shell 6. As a result, it is advantageous to bring the conical outer periphery of the cylindrical dense refractory 16 closer to or in close contact with the conical inner periphery of the outer iron shell 6. For this reason, the sealing performance of the boundary region between the conical outer periphery of the cylindrical dense refractory 16 and the conical inner periphery of the outer iron shell 6 can be further enhanced. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

(Embodiment 7)
FIG. 6 shows a seventh embodiment. The present embodiment has basically the same configuration and the same function and effect as the above-described embodiment. Also in the present embodiment, as shown in FIG. 6, a ring-shaped concave pool portion 1W around the axis P1 is formed in the boundary region between the cylindrical dense refractory 16 and the cylindrical outer iron shell 6. ing. The recessed pool portion 1W is formed so as to make one round in the outer peripheral portion of the cylindrical dense refractory 16. At the time of assembly, the recessed pool portion 1W is loaded with an unfired or semi-fired heat resistant sealant. This heat-resistant sealant is fired by heat during use to form the heat-resistant ceramic pool portion 1R. The heat-resistant ceramic pool portion 1R is formed in a ring shape around the axis P1. The heat-resistant ceramic pool portion 1R is formed of mullite or spinel that expands when synthesized, and expands in the radial direction and the height direction. As a result, the outer peripheral portion of the cylindrical dense refractory 16 and the cylindrical shape are formed. The boundary region with the inner periphery of the outer iron skin 6 is sealed. For this reason, it is suppressed that the gas of the gas pool 18 leaks from the upper end 6up side of the iron skin 6 through the said boundary area | region.

  Furthermore, according to the present embodiment, as shown in FIG. 6, in the boundary region between the cylindrical upper porous refractory 1 and the auxiliary dense refractory 16, a ring-shaped concave pool portion 16W is formed around the axis P1. ing. The recessed pool portion 16W is filled with an unfired heat resistant sealant. When the loaded heat-resistant sealant is baked (synthesized) by heat during use, it forms mullite or spinel and expands in the radial direction and the height direction to form the heat-resistant ceramic pool portion 16R. This expansion exists as a residual expansion. As a result, an urging force FA (see FIG. 6) toward the upper end 6up of the outer iron shell 6 is exhibited. As a result, the outer periphery of the conical shape of the auxiliary dense refractory 16 (cone that decreases in diameter toward the upper part) approaches the inner peripheral part of the conical shape of the outer iron shell 6 (cone that decreases in diameter toward the upper part). Or it is advantageous for close contact. Therefore, the sealing performance of the boundary region between the conical outer periphery of the auxiliary dense refractory 16 and the conical inner periphery of the outer iron shell 6 can be further enhanced. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed. As shown in FIG. 6, the heat resistant ceramic pool portion 1 </ b> R is positioned above the center height position Hm in the iron skin 6. In particular, the heat-resistant ceramic pool portion 1R is preferably positioned above the position Hx in the height direction in the iron skin 6. This is because the iron skin 6 disposed on the lower side of a hot water storage container such as tundish is vigorously heated from the upper side thereof, and the upper side of the iron skin 6 is exposed to a severe high temperature environment, so that it is preferable to improve the sealing property. The cross sections of the recessed pool portion 1W and the heat resistant ceramic pool portion 1R are substantially trapezoidal, but they may be triangular in cross section.

(Embodiment 8)
7 and 8 show an eighth embodiment. The present embodiment has basically the same configuration and the same function and effect as the above-described embodiment. This embodiment is a case where it applies to the blowing plug (high temperature assembly) attached so that it may be embed | buried under the bottom wall W of a ladle. The blow plug includes a refractory layer 30 (the other of the first member and the second member) and an iron skin 32 (one of the first member and the second member) surrounding the outer peripheral portion 30p of the refractory layer 30. And a gas supply pipe 33 connected to the bottom 32 b of the iron skin 32. The refractory layer 30 includes a gas passage 35 for blowing hubring gas into the molten metal M, a gas pool chamber 36 formed between the lower surface 30 d of the refractory layer 30 and the iron shell 32 and communicating with the gas passage 35. It has. Between the outer peripheral portion 30p of the refractory layer 30 and the inner peripheral portion 32i of the iron shell 32, a seal layer 38 to which a heat resistant sealant is applied is formed. Similarly to the first embodiment, the ceramic of the heat-resistant sealant that forms the seal layer 38 contains alumina particles (Al ₂ O ₃ ) and silica particles (SiO ₂ ) as main components (active components). The ceramic composition of the heat-resistant sealant preferably contains more alumina (Al ₂ O ₃ ) than silica (SiO ₂ ) by mass ratio. For example, silica (SiO _2), silica materials containing more alumina than _{(SiO 2) (Al 2 O} 3) can be used a heat-sealing agent which is kneaded with water. Then, the heat-resistant sealant is applied to the outer peripheral portion 30 p of the refractory layer 30 and / or the inner peripheral portion 32 i of the iron skin 32. Thus, the sealing agent before baking is apply | coated to the said border region. Thereafter, the refractory layer 30 and the iron skin 32 are assembled. If the blowing plug in this state is used, the blowing nozzle is maintained in a high temperature region. In this case, the blow plug is embedded in the bottom wall W of the ladle that stores the high-temperature molten metal M of about 1400 to 1700 ° C., for example. For this reason, in the sealing agent heated by the heat received from the molten metal M, a reaction such as the above-described formula (1) occurs, and mullite is synthesized. Therefore, in the boundary region between the outer peripheral portion 30p of the refractory layer 30 (one of the first member and the second member) and the inner peripheral portion 32i of the iron shell 32 (the other of the first member and the second member). Sealability can be improved. If necessary, kyanite can be added to the heat-resistant sealant before firing.

  According to the present embodiment, as shown in FIG. 7, a ring-shaped concave pool portion 1 </ b> W around the axis P <b> 1 is formed in the boundary region between the refractory layer 30 and the cylindrical iron shell 32. The concave pool portion 1 </ b> W is formed so as to make one round at the outer peripheral portion of the refractory layer 30. At the time of assembly, the recessed pool portion 1W is loaded with a heat-resistant sealant. This heat-resistant sealant is baked by heat during use, that is, by the heat of the molten metal M, so that the heat-resistant ceramic pool portion 1R is formed. The heat-resistant ceramic pool portion 1R is formed in a ring shape around the axis P1. The heat resistant ceramic pool portion 1R is formed of mullite that expands when synthesized, and expands in the radial direction and the height direction. As a result, the sealing performance for sealing the boundary region between the upper part of the outer peripheral part of the refractory layer 30 and the upper part of the inner peripheral part of the iron shell 32 is enhanced. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed. The heat-resistant ceramic pool portion 1R is positioned above the center position Hm of the height dimension of the iron skin 32. This is because the upper surface of the iron skin 6 is exposed to a high-temperature environment because the iron skin 32 is heated intensely from the upper side thereof, so that it is preferable to improve the sealing performance.

  As shown in FIG. 7, the concave pool portion 1W and the heat-resistant ceramic pool portion 1R have a substantially triangular cross section. The oblique side portion 101 along the inner wall surface of the iron shell 32, the upper oblique side portion 102, and the lower side It has a hypotenuse 103 and an intersection 104. Since the hypotenuse part 102 is long, the intersecting part 104 is positioned relatively on the lower side. For this reason, the thickness of the part 30x (refer FIG. 7) which faces the hypotenuse part 102 among the refractory layers 30 is ensured in the radial direction (arrow DA direction).

(Embodiment 9)
Since this embodiment basically has the same configuration and the same operation and effect as the eighth embodiment shown in FIGS. 7 and 8, the FIGS. 7 and 8 are applied mutatis mutandis. The heat resistant sealant forms the seal layer 38 and the heat resistant ceramic pool portion 1R. As in Embodiment 1, the heat-resistant sealant contains alumina particles (Al ₂ O ₃ ) and magnesia particles (MgO) as main components (active ingredients) and is synthesized by heat during use to form spinel. To do. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed.

(Embodiment 10)
FIG. 9 shows a tenth embodiment. The present embodiment has basically the same configuration and the same function and effect as the first embodiment. As shown in FIG. 9, in the boundary region between the outer peripheral portion of the cylindrical porous refractory 1X (refractory) and the inner peripheral portion of the cylindrical outer iron shell 6, a ring-shaped concave pool portion 1W1 around the axis P1 is provided. , 1W2 is formed. The recessed pool portions 1W1 and 1W2 are formed so as to make one round on the outer peripheral portion of the cylindrical porous refractory 1X. At the time of assembly, the heat resistant sealant is loaded in the concave pool portions 1W1 and 1W2. This heat-resistant sealant is fired (synthesized) by heat during use, that is, by the heat of the molten metal passing through the passage 7 to form the heat-resistant ceramic pool portions 1R1 and 1R2. The heat-resistant ceramic pool portions 1R1, 1R2 are formed in a ring shape around the axis P1, and are formed of mullite or spinel that expands by firing. The heat-resistant ceramic pool portions 1R1 and 1R2 seal the boundary region between the upper part of the outer peripheral part of the conical shape of the cylindrical porous refractory 1X and the upper part 6u of the inner peripheral part of the conical shape of the cylindrical outer iron shell 6. Yes. In particular, the heat-resistant ceramic pool portions 1R1 and 1R2 are thicker than the thickness of the outer iron shell 6, and the residual expansion amount in the radial direction (direction perpendicular to the axis P1) is ensured satisfactorily. As a result, it is possible to satisfactorily seal the boundary region between the upper portion of the outer peripheral portion of the cylindrical porous refractory 1X and the upper portion 6u of the cylindrical outer iron shell 6. Here, the upper part means the upper side of the height position Hm which is half the height dimension HA of the iron skin 6. The heat-resistant ceramic pool portion 1R is located above the position Hm in the iron skin 6. In particular, it is preferably located above the position Hx. As a result, the gas blown into the gas pool 19 or the like is effectively suppressed from leaking from the boundary region to the upper end 6up side of the outer iron shell 6. Since the cylindrical porous refractory 1X is a porous material having a large number of pores, the expansion is absorbed by the pores, so there is a limit to the expansion. In this respect, according to the present embodiment, the ring-shaped heat-resistant ceramic pool portions 1R1 and 1R2 are formed in a plurality of steps (two steps) in the height direction above the position Hm, which is advantageous for securing the expansion amount. is there.

  As shown in FIG. 9, the thickness of the upper heat-resistant ceramic pool portion 1R1 is shown as a11. The thickness of the lower heat-resistant ceramic pool portion 1R1 is shown as a12. In this case, the relationship is a11> a12. The boundary region between the upper part of the cylindrical porous refractory 1X and the upper part of the cylindrical outer iron shell 6 can be satisfactorily sealed. During use, the iron skin 6 is also heated intensely from above, so that the upper part of the iron skin 6 is exposed to a more severe environment. For this reason, the advantage which can exhibit the effect of a heat-resistant sealing agent more effectively by the relationship of a11> a12 is acquired. As a result, the gas blown into the gas pool 19 or the like is prevented from leaking from the boundary region to the upper end 6up side of the outer iron shell 6. As in Embodiment 1, the heat-resistant sealant is synthesized by heat during use to form mullite or spinel. In addition, the heat-resistant sealing agent before baking can contain at least one of a kyanite and an andalusite as needed. However, depending on the use environment, the relationship may be a11 <a12 or a11 = a12.

  As shown in FIG. 9, the upper part of the cylindrical porous refractory 1 </ b> X has a conical shape, and the thickness in the radial direction (DA direction) is reduced. For this reason, in order to ensure the thickness of the cylindrical porous refractory 1X in the DA direction as much as possible, the cross sections of the concave pool portion 1W1 and the heat-resistant ceramic pool portion 1R1 positioned relatively on the upper side are substantially triangular. However, the cross sections of the recessed pool portion 1W1 and the heat-resistant ceramic pool portion 1R1 positioned relatively below are substantially rectangular or trapezoidal. This is because the heat-resistant ceramic pool portion 1R1 is on the lower side, so that the thickness of the porous refractory 1X in the DA direction can be secured.

(Embodiment 11)
FIG. 10 shows an eleventh embodiment. The present embodiment has basically the same configuration and the same function and effect as the first embodiment. As shown in FIG. 10, a dense ring-shaped dense refractory 1 </ b> M having a lower porosity than that of the dense porous refractory 1 </ b> M is coaxially provided on the outer peripheral portion of the cylindrical porous refractory 1 </ b> X. In the boundary region between the outer periphery of the dense refractory 1M and the inner periphery of the cylindrical outer iron shell 6, that is, the outer periphery of the dense refractory 1M has a ring-shaped concave pool portion 1W1, around the axis P1. 1W2 is formed in a plurality of upper and lower stages. The concave pool portions 1W1 and 1W2 are formed so as to make one round in the outer peripheral portion of the dense refractory 1M. When assembled, the recessed pool portions 1W1 and 1W2 are loaded with an unfired (non-synthesized) heat-resistant sealant. The heat-resistant sealant before firing can contain at least one of kyanite and andalusite as necessary. This heat-resistant sealant is fired (synthesized) by heat during use, that is, by the heat of the molten metal passing through the passage 7 to form the heat-resistant ceramic pool portions 1R1 and 1R2 up and down. The heat-resistant ceramic pool portions 1R1, 1R2 are formed in a ring shape around the axis P1, and are formed of mullite or spinel that expands by firing. Since the inner peripheral side of the heat-resistant ceramic pool portions 1R1 and 1R2 is a dense refractory 1M having high density, the radial expansion of the heat-resistant ceramic pool portions 1R1 and 1R2 is ensured well, and the boundary region described above Improved sealing performance.

(Test example)
A test was conducted on a heat-resistant sealant for forming the heat-resistant ceramic pool portion 1R and the like. In this test example, ceramics of the heat-resistant sealant is 70% alumina particles (Al ₂ O ₃ ) having a mass ratio of 75 micrometers or less and 15% alumina particles (Al ₂ O ₃ ) having a diameter of 10 micrometers or less. Silica particles (SiO ₂ ) of 1 micrometer or less were blended at 15%. And the heat-resistant sealing agent was formed by mixing water and ceramics as a dispersion medium. This heat-resistant sealant was applied to the boundary region between the first member (material: high alumina) and the second member (material: high alumina). The coating thickness was 1 mm. Then, the gas was allowed to flow from the inlet toward the outlet while being heated to 1500 ° C. with a burner combustion flame from the outside. And the leak flow rate of the gas discharged | emitted from an exit was measured. The nozzle back pressure was maintained at 0.2 kg / cm ² . As a comparative example, a mortar conventionally used was used, and the test was performed under the same conditions as in the test example.

  The test results are shown in FIG. In FIG. 11, the ● marks indicate test examples of the present invention. ◆ indicates a comparative example. As shown by the asterisks in FIG. 11, in the comparative example, the leaked gas flow rate has increased since about 20 minutes have passed since the start of the test. Further, as shown by the ● marks in FIG. 11, in the test example, the leaked gas flow rate does not increase even after 120 minutes have elapsed from the start of the test. From this, it can be seen that the heat-resistant sealant according to the present invention can stably obtain high sealing performance in a high temperature region.

  An example of the seal layer after 120 minutes from the start of the test was observed with an optical microscope. The result is shown in FIG. As shown in FIG. 12, the seal layer was in close contact with the nozzle body. Looking at the boundary between the nozzle body and the seal layer, it is estimated that there is a possibility that melting has occurred in part. It is considered that fine silica particles are melted. Although island-like pores (black portions) are generated in the seal layer, the pores are not open pores but closed pores. This also shows that the sealing performance of the sealing layer of the present invention is improved. It is inferred that the volume expansion is more affected by the mullite synthesis than before the reaction. Closed pores are considered advantageous for volume expansion. In the sealing layer, the ceramic portion other than the pores was dense. This also shows that the sealing performance of the sealing layer of the present invention is further improved.

  (Others) The present invention is not limited to the embodiment described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist. The combination of the first member and the second member may be a combination of refractory-refractory, metal-metal, refractory-metal, metal-refractory. Mortar may be used as the heat-resistant sealant. Mortar is a binder made by mixing sand (fine aggregate), cement and water. As a use of the high temperature assembly of the present invention, it can be widely used in a high temperature region in which a molten metal such as molten steel, molten iron, molten aluminum, and molten titanium is used, a high temperature region exposed to a high temperature gas, and the like.

  1X is a cylindrical porous refractory, 1W is a concave pool portion, 1R is a heat resistant ceramic pool portion, 1 is an upper porous refractory, 2 is a lower porous refractory, 3 is a dense refractory, 3a is an upper dense refractory, 3b is a lower dense refractory, 4 is an upper gas introduction passage, 5 is a lower gas introduction passage, 6 is an outer iron skin, 7 is a passage, 8 is a seal layer, and 9 is an iron skin.

Claims (6)

  A first member formed of metal or refractory, a second member formed of metal or refractory facing the first member, and a boundary region between the first member and the second member. As described above, the concave pool portion formed in at least one of the first member and the second member and the heat-resistant sealant that is loaded into the concave pool portion and synthesized by heat during use and expands in volume are fired. A high-temperature assembly comprising a heat-resistant ceramic seal portion formed.   2. The ceramic according to claim 1, wherein the ceramic that expands in volume when synthesized is mullite, the heat-resistant sealant includes first ceramic particles and second ceramic particles, and the first ceramic particles are formed of silica, and the second ceramics. A high temperature assembly wherein the particles are made of alumina.   2. The ceramic according to claim 1, wherein the ceramic that expands in volume when synthesized is spinel, the heat-resistant sealant includes first ceramic particles and second ceramic particles, and the first ceramic particles are formed of magnesia, A high temperature assembly wherein the particles are made of alumina.   In one of Claims 1-3, one particle size of the said 1st ceramic particle and the said 2nd ceramic particle is 30 micrometers or less, and the other particle size is 200 micrometers or less. A featured high temperature assembly.   In one of Claims 1-4, when the ceramics in the said heat-resistant sealant are 100%, one or both of andalusite and kyanite are contained in a mass ratio of 0.01 to 40%. High temperature assembly characterized by that. A first step of preparing a heat-resistant sealant containing a plurality of types of ceramic particles that undergo volume expansion when synthesized, a first member, and a second member;
An assembled body is assembled by assembling at least the first member and the second member in a state where the heat-resistant sealant is loaded in a concave pool portion formed in a boundary region between the first member and the second member. A second step of forming;
The assembled body when the assembled body is used in a state where the heat resistant sealant is loaded in the concave pool portion formed in a boundary region between the first member and the second member of the assembled body. The heat-resistant sealant is heated at at least one of a use temperature of the assembly, a preheating temperature of the assembly before use of the assembly, and a heating temperature of the assembly before delivery of the assembly A third step of sealing the boundary region between the first member and the second member of the assembly by forming a synthetic ceramic that is volume-expanded by synthesizing the plurality of types of ceramic particles. A method for producing a high-temperature assembly comprising: