CN116274985A - Anti-blocking submerged nozzle for special steel continuous casting and preparation method thereof - Google Patents

Anti-blocking submerged nozzle for special steel continuous casting and preparation method thereof Download PDF

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Publication number
CN116274985A
CN116274985A CN202310021027.8A CN202310021027A CN116274985A CN 116274985 A CN116274985 A CN 116274985A CN 202310021027 A CN202310021027 A CN 202310021027A CN 116274985 A CN116274985 A CN 116274985A
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heat
continuous casting
submerged nozzle
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conducting layer
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陈天琪
钱伊希
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Jiangsu Xinhu Refractories Co ltd
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Jiangsu Xinhu Refractories Co ltd
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    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/02—Linings
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    • B22—CASTING; POWDER METALLURGY
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    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
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    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
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    • C04B2235/38—Non-oxide ceramic constituents or additives
    • C04B2235/3852—Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
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Abstract

The application discloses an anti-blocking submerged nozzle for special steel continuous casting and a preparation method thereof. The anti-blocking submerged nozzle for continuous casting of special steel comprises a main body, wherein the main body consists of a heat conducting layer and a heat insulating layer which are sequentially connected from inside to outside, and the heat conducting layer is contacted with molten steel; wherein the heat conducting layer is prepared from the following raw materials in percentage by weight: 60-80% of electro-fused corundum, 4-11% of silicon carbide, 14-25% of aluminum nitride and 2-4% of boron nitride; an adhesive is added into the heat conducting layer; the heat insulation layer is prepared from the following raw materials in percentage by weight: 65-75% of fused corundum, 5-8% of mullite, 6-11% of glass fiber and 14-16% of silicon nitride; and a bonding agent is added into the heat insulating layer. According to the method, the heat conduction layer and the heat insulation layer are matched, so that the anti-caking performance of the submerged nozzle can be remarkably improved, and the number of continuous casting furnaces for titanium-containing steel is up to more than 16.

Description

Anti-blocking submerged nozzle for special steel continuous casting and preparation method thereof
Technical Field
The application relates to the technical field of refractory materials, in particular to an anti-blocking submerged nozzle for special steel continuous casting and a preparation method thereof.
Background
Refractory materials for continuous casting are generally used for producing functional parts such as submerged nozzles. The submerged nozzle has the functions of guiding molten steel and the like, and is an important component in a continuous casting machine set. The domestic submersed nozzle mainly comprises fused quartz, aluminum carbon and zirconium carbon.
At present, chinaZirconium carbon immersion nozzle body for continuous casting mainly adopts Al 2 O 3 ZrO is adopted at the slag line part of the-C composite material 2 -C composite material. Due to Al 2 O 3 C and SiO in the host material 2 Meanwhile, the aluminum oxide is easy to generate on the inner wall of the water gap, so that the blocking of the water gap is quickened.
Particularly, the frequency of water gap replacement is higher for smelting titanium-containing special steel. The special steel material containing titanium contains nitrogen and titanium, and CaO and TiO exist in molten steel formed by melting 2 Inclusions or CaO/TiO-rich products 2 CaO-TiO of (2) 2 -MgO-Al 2 O 3 Composite inclusions. The molten steel passes through the initial cold steel layer, and the inclusions are continuously accumulated and grown on the rough surface, thereby forming the steel rich in CaO and TiO 2 Is a dendritic plug of (a).
Meanwhile, with the increase of the dendritic blocking object volume, a large-aperture gap is formed in the blocking object, so that the molten steel is caused to stay in the gap for a short time, tiN in the molten steel can be separated out, the molten steel containing the TiN is cooled and solidified on the surface of the blocking object, the blocking of a water gap is serious, the molten steel is biased, attachments are involved, defects such as inclusion and the like are caused, and the melting loss generated by erosion of protective slag added into a crystallizer is large.
Aiming at the related technology, the conventional zirconium carbon submerged nozzle can only ensure that the submerged nozzle is not blocked on the premise that the titanium-containing special molten steel of a continuous casting 3-4 furnace is not more than 1000 tons. Therefore, how to improve the number of continuous casting furnaces for titanium-containing special steels is less, and the problem that a submerged nozzle is easy to be blocked is a problem to be solved in the industry.
Disclosure of Invention
In order to solve the problems that the number of furnaces for continuous casting of titanium-containing special steel is small and the submerged nozzle is easy to block, the application provides an anti-blocking submerged nozzle for continuous casting of special steel and a preparation method thereof.
In a first aspect, the application provides a special steel continuous casting is with preventing blockking up immersion nozzle that adopts following technical scheme:
the anti-blocking submerged nozzle for continuous casting of special steel comprises a main body, wherein the main body consists of a heat conducting layer and a heat insulating layer which are sequentially connected from inside to outside, and the heat conducting layer is contacted with molten steel;
wherein the heat conducting layer is prepared from the following raw materials in percentage by weight:
60-80% of electro-fused corundum, 4-11% of silicon carbide, 14-25% of aluminum nitride and 2-4% of boron nitride; the adhesive is added into the heat conduction layer, and the adhesive accounts for 10-15% of the total weight of the raw materials of the heat conduction layer;
the heat insulation layer is prepared from the following raw materials in percentage by weight:
65-75% of fused corundum, 5-8% of mullite, 6-11% of glass fiber and 14-16% of silicon nitride; the heat insulating layer is added with a bonding agent, and the bonding agent accounts for 10-15% of the total weight of the heat insulating layer raw materials.
Through adopting above-mentioned technical scheme, the submerged nozzle passes through the structure and the material cooperation of main part, can reduce the possibility that cold steel layer formed in continuous casting initial stage, can prolong cold steel layer's formation time in continuous casting later stage, and its concrete principle is as follows:
the main part of immersion nozzle makes bilayer structure, and the one deck that contacts with molten steel is the heat conduction layer, and the immersion nozzle preheats the heat conduction layer before using earlier, and the heat conduction layer evenly transmits the heat to the inner wall of main part for the inner wall heat is even. The heat insulation layer can enable the inner wall of the main body to maintain stable high temperature for a long time, and the temperature is close to the temperature of molten steel; when the molten steel contacts with the water gap, the temperature difference between the molten steel and the water gap is small, and the molten steel is not easy to cool on the inner wall of the water gap.
The heat conducting layer is made of silicon carbide, aluminum nitride and boron nitride materials to modify corundum, and the silicon carbide has high heat conductivity coefficient and can rapidly and uniformly distribute heat, so that the temperature of each part of the heat conducting layer is uniform; meanwhile, aluminum nitride can be sintered with aluminum oxide in nitrogen atmosphere to form aluminum oxynitride phase, the aluminum oxynitride phase can ensure that the heat resistance of the heat conducting layer is excellent, the preheating temperature of the water gap is improved, the water gap is kept at high temperature, and TiN and TiO are reduced 2 And the possibility of precipitation of complex titanium oxides on cooling. Aluminum oxynitride and boron nitride exist in the heat conduction layer, so that the wettability of molten steel on the heat conduction layer can be effectively reduced, and the aluminum oxide and titanium oxide can be slowed downAnd the adhesion possibility of the composite inclusion on the heat conductive layer. Further reduces the possibility of the attachment of inclusions to the inner wall of the nozzle. The boron nitride forms boron oxide with low melting point after being melted at high temperature, and the boron oxide further fills some unsealed air holes, thereby further avoiding the inclusion in the molten steel from being adsorbed on the inner wall of the water gap.
The heat insulating layer is made of mullite, glass fiber and silicon nitride and is used for modifying corundum, the heat conductivity coefficient of the heat insulating layer is low, a good heat insulating effect is achieved, the possibility of temperature loss of the heat conducting layer can be effectively reduced, and the heat insulating layer is matched with the heat conducting layer, so that the molten steel condensation nodulation time can be prolonged.
In addition, the heat insulating layer is made of mullite, glass fiber and silicon nitride, so that the bonding strength between the heat conducting layer and the heat insulating layer can be improved. And secondly, the pore structure between silicon carbide is improved through aluminum oxynitride phase generated by aluminum nitride and aluminum oxide, so that the problem of strength reduction caused by silicon carbide with high addition is solved, and the heat conducting layer has more excellent thermal shock resistance. Meanwhile, mullite and silicon carbide are sintered at high temperature, rearrangement and bonding among particles are promoted at high temperature, liquid phase is filled among mullite particles, and the density of the heat insulation layer is improved after cooling. Therefore, the thermal shock resistance of the whole submerged nozzle is remarkably improved.
In summary, the structure and the materials of the main body are improved, so that the submerged nozzle has the characteristics of excellent blocking resistance and thermal shock resistance.
Preferably, the heat conducting layer comprises the following raw materials in percentage by weight: 65-67% of electro-fused corundum, 6-10% of silicon carbide, 20-25% of aluminum nitride and 3-4% of boron nitride.
Preferably, the heat insulation layer comprises the following raw materials in percentage by weight: 65-70% of electro-fused corundum, 6-7% of mullite, 8-10% of glass fiber and 15% of silicon nitride.
By adopting the technical scheme, the proportion of the heat conducting layer and the insulating layer is optimized, so that the anti-nodulation performance and the thermal shock resistance of the submerged nozzle can be obviously improved.
Preferably, the particle size of the aluminum nitride in the heat conducting layer is 3-5 μm.
By adopting the technical scheme, aluminum nitride with proper grain size is selected, so that the aluminum nitride has better dispersibility, can be fully dispersed in raw materials, and further improves the thermal shock resistance of the submerged nozzle.
Preferably, the mixing amount of the adhesive is 12-13%, and the mixing amount of the adhesive is 12-13%.
By adopting the technical scheme, the adhesive and the bonding agent can be the same or different, and the selection of the adhesive and the bonding agent comprises one or more of phenolic resin and dextrin. The blending amount of the adhesive and the binder is optimized in the application, so that the adhesive strength between the heat conducting layer and the heat insulating layer is not reduced while raw materials are uniformly mixed.
Preferably, the thickness ratio of the heat conduction layer to the heat insulation layer is 1 (2-3).
In a second aspect, the present application provides a method for preparing an anti-blocking submerged nozzle for continuous casting of special steel, which adopts the following technical scheme:
a preparation method of an anti-blocking submerged nozzle for continuous casting of special steel comprises the following steps:
preparing raw materials in the heat conducting layer and the heat insulating layer, grinding and crushing the raw materials to be less than 150 meshes, and sieving for later use;
mixing the raw materials according to the formula to obtain a heat conducting layer and a heat insulating layer respectively, adding an adhesive into the heat conducting layer according to the formula, adding the adhesive into the heat insulating layer, and pressing into a green brick under the pressure of 50-100 MPa;
heating the green bricks to 600-700 ℃ under nitrogen atmosphere, and preserving heat and calcining for 2-3 h; and then heating to 1660-1800 ℃ and preserving heat for secondary calcination for 2-4 h to obtain the finished product of the submerged nozzle.
By adopting the technical scheme, the preparation method of the submerged nozzle is simple and convenient, the submerged nozzle can maintain high temperature in the preheating stage, the possibility of the inner wall nodulation of the initial nozzle is reduced, and the number of continuous casting furnaces is prolonged.
Preferably, the temperature of secondary calcination of the green bricks is 1700-1750 ℃, and the secondary calcination is carried out for 2-3 hours.
By adopting the technical scheme, the calcination temperature and the calcination time are optimized in the application, so that most of aluminum nitride is converted into a nitrogen-rich aluminum oxynitride phase, and the anti-clogging performance of the submerged nozzle is further improved.
In summary, the present application has the following beneficial effects:
the immersion nozzle is made into a double-layer structure, the heat conduction layer contacted with molten steel conducts heat rapidly, the heat insulation layer can prolong the heat dissipation time, the inner wall of the immersion nozzle can maintain long-term high temperature after preheating treatment, and the molten steel condensation nodulation time can be prolonged.
Detailed Description
Currently, submerged nozzles for continuous casting of specialty steels are generally zirconium-carbon, i.e., al is used 2 O 3 -C composite material as host material, zrO 2 -C composite material as slag line site. The zirconium-carbon submerged nozzle material is not suitable for smelting titanium-containing special steel, because CaO-TiO exists in the titanium-containing special molten steel 2 Inclusions or CaO/TiO-rich products 2 CaO-TiO of (2) 2 -MgO-Al 2 O 3 Composite inclusions are easy to deposit on the inner wall material of the submerged nozzle. And TiN in the molten steel can be separated out in the casting process, so that the nozzle is seriously blocked. Through experiments, the number of continuous casting furnaces of the traditional zirconium carbon immersion nozzle is only 3-4 furnaces, and the steel passing amount is not more than 1000 tons.
In view of the above problems, the applicant has studied on the structure, material and preparation method of the submerged nozzle, and found that: the main part of immersion nozzle makes bilayer structure, and the one deck that contacts with molten steel is the heat conduction layer, and the immersion nozzle preheats the heat conduction layer before using earlier, and the heat conduction layer evenly transmits the heat to the inner wall of main part for the inner wall heat is even. The heat insulation layer can enable the inner wall of the main body to maintain stable high temperature for a long time, and the temperature is close to the temperature of molten steel; when molten steel contacts with the water gap, the temperature difference between the molten steel and the water gap is small, the molten steel is not easy to cool on the inner wall of the water gap, the possibility of forming a cold steel layer can be reduced in the initial stage of continuous casting, and the forming time of the cold steel layer can be prolonged in the later stage of continuous casting.
Carbon is selected for the heat conducting layerThe corundum is modified by silicon carbide, aluminum nitride and boron nitride materials, and the three materials have synergistic effect in the aspects of anti-blocking and thermal shock resistance. The silicon carbide has high heat conductivity coefficient, and can rapidly and uniformly distribute heat, so that the temperature of each part of the heat conducting layer is relatively uniform; meanwhile, aluminum nitride can be sintered with aluminum oxide in nitrogen atmosphere to form aluminum oxynitride phase, the aluminum oxynitride phase can ensure that the heat resistance of the heat conducting layer is excellent, the preheating temperature of the water gap is improved, the water gap is kept at high temperature, and TiN and TiO are reduced 2 And the possibility of precipitation of complex titanium oxides on cooling.
And secondly, the aluminum oxynitride phase is granular, and can effectively fill the pores among long whisker-shaped silicon carbide and among flaky boron nitride, so that the problem of strength reduction caused by silicon carbide and boron nitride with high addition is solved, and the aluminum oxynitride phase has more excellent thermal shock resistance. Furthermore, aluminum oxynitride and boron nitride exist in the heat conduction layer, so that the wettability of molten steel on the heat conduction layer can be effectively reduced, and the adhesion possibility of aluminum oxide, titanium oxide and composite inclusions on the heat conduction layer is reduced. Further reduces the possibility of the attachment of inclusions to the inner wall of the nozzle.
Finally, boron nitride forms low-melting-point boron oxide after being melted at high temperature, and the boron oxide further fills some unsealed air holes, so that impurities in molten steel are further prevented from being adsorbed on the inner wall of the water gap.
The heat insulating layer is modified by mullite, glass fiber and silicon nitride, and the combined action of the mullite, the glass fiber and the silicon nitride can enhance the bonding strength between the heat conducting layer and the heat insulating layer. Meanwhile, the heat conductivity coefficient of the heat insulating layer is obviously reduced, a good heat insulating effect is achieved, the possibility of temperature loss of the heat conducting layer can be effectively reduced, and the condensation nodulation time of molten steel can be prolonged by matching the heat insulating layer.
Secondly, mullite and silicon carbide are sintered at high temperature, rearrangement and bonding among particles are promoted at high temperature, liquid phase is filled among mullite particles, and the density of the heat insulation layer is improved after cooling. Meanwhile, the fibrous structure of the glass fiber enables more stress dispersion points to exist in the heat insulation layer, so that the main material has better toughness and excellent thermal shock stability.
Therefore, the technical problem is successfully solved. The thermal shock stability of the submerged nozzle can also be successfully improved.
Al of the fused corundum in the following examples and comparative examples unless otherwise specified 2 O 3 The content is more than or equal to 99 percent;
the aluminum nitride powder is selected from the following three specifications:
particle size 3-5 μm, trade mark Destek040M;
particle size 40-80 nm, brand XT-AlN;
particle size 15 μm, brand XC-1083;
glass fiber: class a, cat No. 210;
the boron nitride is hexagonal boron nitride with the grain diameter of 5-15 mu m;
the adhesive and the binder are phenolic resin, and are purchased from Jinan Dahui chemical technology Co., ltd., brand 2123.
Examples
Example 1
A special steel continuous casting is with preventing blockking up submerged nozzle, its formula is as follows:
the total weight of the raw materials of the heat conducting layer is calculated according to 100 parts, wherein, 60 parts of fused corundum, 11 parts of silicon carbide, 14 parts of aluminum nitride and 22 parts of boron nitride; the mixing amount of the adhesive phenolic resin is 8 parts;
the total weight of the raw materials of the heat insulating layer is calculated according to 100 parts, wherein 65 parts of fused corundum, 8 parts of mullite, 11 parts of glass fiber and 16 parts of silicon nitride; the mixing amount of the adhesive phenolic resin is 11 parts.
The method comprises the following steps:
grinding and crushing fused corundum, silicon carbide, aluminum nitride, boron nitride, mullite and silicon nitride until the granularity of each raw material is below 150 meshes, wherein the aluminum nitride is XC-1083, and sieving for later use;
selecting raw materials according to the formula of the heat conducting layer, and mixing to obtain a heat conducting layer material; weighing, calculating the weight of the adhesive according to a proportion, adding the adhesive into the main material, and stirring and blending to obtain a preformed heat conducting layer;
selecting raw materials according to the formula of the heat insulation layer, and mixing to obtain a heat insulation layer material; weighing, calculating the weight of the adhesive according to a proportion, adding the adhesive into the heat insulation layer material, and stirring and blending to obtain a preformed heat insulation layer;
the preformed heat conducting layer and the preformed heat insulating layer are attached according to the thickness ratio of 1:1, and then are placed in a die and pressed into green bricks under the pressure of 100 MPa;
heating the green bricks to 600 ℃ under nitrogen atmosphere, and preserving heat and calcining for 3 hours; and heating to 1660 ℃ and calcining for 4 hours to obtain the finished product of the submerged nozzle.
Examples 2 to 7
The anti-clogging submerged nozzle for continuous casting of special steel is different from example 1 in the raw material composition of the heat insulating layer and the heat conducting layer, and the specific composition is shown in the following table 1.
TABLE 1 composition of the body
Figure 486874DEST_PATH_IMAGE001
Example 8
The anti-blocking submerged nozzle for continuous casting of special steel is different from the embodiment 5 in that: the aluminum nitride with the grain size of 15 μm is replaced by the weight parts such as aluminum nitride with the grain size of 3-5 μm.
Example 9
The anti-blocking submerged nozzle for continuous casting of special steel is different from the embodiment 5 in that: the aluminum nitride with the grain size of 15 mu m is replaced by the weight parts such as aluminum nitride with the grain size of 40-80 nm.
Examples 10 to 12
The anti-blocking submerged nozzle for continuous casting of special steel is different from the embodiment 8 in that: the mixing amounts of the adhesive and the bonding agent are different, and the concrete steps are as follows:
the blending amount of the adhesive and the binder in example 10 was 12 parts;
the blending amount of the adhesive and the binder in example 11 was 13 parts;
the amounts of the binder and the adhesive in example 12 were 15 parts.
Examples 13 to 15
The anti-blocking submerged nozzle for continuous casting of special steel is different from example 11 in that: the processing parameters are different, and the method is as follows:
in the embodiment 13, the green bricks are heated to 600 ℃ under the nitrogen atmosphere and are subjected to heat preservation and primary calcination for 3 hours; then heating to 1700 ℃, preserving heat and calcining for 3 hours to obtain a finished product of the submerged nozzle;
in the embodiment 14, the green bricks are heated to 600 ℃ under the nitrogen atmosphere and are subjected to heat preservation and primary calcination for 3 hours; then heating to 1750 ℃ and preserving heat for secondary calcination for 2 hours to obtain a finished product of the submerged nozzle;
in the embodiment 15, the green bricks are heated to 700 ℃ under the nitrogen atmosphere and are subjected to heat preservation and primary calcination for 2 hours; then heating to 1800 ℃ and preserving heat for secondary calcination for 2 hours to obtain a finished product of the submerged nozzle;
examples 16 to 18
An anti-clogging submerged nozzle for continuous casting of special steel, which differs from example 14 in that: the thickness ratio of the heat conduction layer and the heat insulation layer is different, specifically as follows;
the thickness ratio of the heat conductive layer to the heat insulating layer in example 16 was 1:2;
the thickness ratio of the heat conductive layer to the heat insulating layer in example 17 was 1:3;
the thickness ratio of the heat conductive layer to the heat insulating layer in example 18 was 1:4.
Comparative example
Comparative example 1
The immersion nozzle for continuous casting of special steel is different from example 1 in that: instead of the heat conductive layer, an insulating layer of equal thickness is used.
Comparative example 2
The immersion nozzle for continuous casting of special steel is different from example 1 in that: a thermally conductive layer of equal thickness is used instead of the thermally insulating layer.
Comparative examples 3 to 8
The immersion nozzle for continuous casting of special steel is different from example 1 in that: the heat insulating layer and the heat conducting layer have different raw material compositions, and the specific compositions are shown in the following table 2:
TABLE 2 composition of the body
Figure 192924DEST_PATH_IMAGE002
Performance test
1. The mechanical properties of the submerged nozzle samples prepared in examples 1 to 18 and comparative examples 1 to 8 were examined under normal temperature and pressure conditions.
2. The applicability test was performed on a steel mill special steel production line. Using the submerged entry nozzle samples prepared in examples and comparative examples of the present application, the blank was a conventional zirconium carbonaceous nozzle (Al was used as the bulk material 2 O 3 ZrO is adopted at the slag line part of the-C composite material 2 -C composite).
The following steel grades were tested: 20MnTiB.
Detection result
TABLE 3 mechanical Properties of submerged entry nozzle samples
Figure 343283DEST_PATH_IMAGE003
Applicability test:
different submerged nozzle samples were used for casting 20MnTiB, steel throughput 1000 tons:
TABLE 4 casting Property of submerged nozzle samples
Figure 298731DEST_PATH_IMAGE004
"/" indicates no detection or complete blockage of the nozzle.
Conclusion of detection
The single comparison of example 1, comparative examples 1-8 and blank control of this application, in combination with tables 3-4, resulted in:
first, the results of the tests in example 1, comparative examples 1-2 and the blank group revealed that: the heat conduction layer and the heat insulation layer are compounded, so that the effects of better internal heat conduction and external heat insulation and heat preservation can be achieved, the number of continuous casting furnaces of the submerged nozzle is increased, and the average thickness of knots is not more than 3.07mm after continuous casting of 10 furnaces;
second, the results of the tests of comparative example 1, comparative examples 3 to 5 and the blank group revealed that: the heat conducting layer material is modified by compounding silicon carbide, aluminum nitride and boron nitride, and has a synergistic effect in improving the thermal shock resistance and anti-nodulation performance of the submerged nozzle;
third, the results of the tests in comparative example 1, comparative examples 6 to 8 and the blank group are as follows: the thermal insulation layer material can remarkably improve the thermal shock resistance by using mullite, glass fiber and silicon nitride.
The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims (8)

1. The utility model provides a special steel continuous casting is with preventing blockking up submerged nozzle, includes main part, its characterized in that:
the main body consists of a heat conducting layer and a heat insulating layer which are sequentially connected from inside to outside, and the heat conducting layer is contacted with molten steel;
wherein the heat conducting layer is prepared from the following raw materials in percentage by weight:
60-80% of electro-fused corundum, 4-11% of silicon carbide, 14-25% of aluminum nitride and 2-4% of boron nitride; the main material is added with an adhesive, and the adhesive accounts for 10-15% of the total weight of the raw materials of the heat conducting layer;
the heat insulation layer is prepared from the following raw materials in percentage by weight:
65-75% of fused corundum, 5-8% of mullite, 6-11% of glass fiber and 14-16% of silicon nitride; the heat insulating layer is added with a bonding agent, and the bonding agent accounts for 10-15% of the total weight of the heat insulating layer raw materials.
2. The anti-clogging submerged nozzle for continuous casting of special steel as claimed in claim 1, wherein: the heat conducting layer comprises the following raw materials in percentage by weight: 65-67% of electro-fused corundum, 6-10% of silicon carbide, 20-25% of aluminum nitride and 3-4% of boron nitride.
3. The anti-clogging submerged nozzle for continuous casting of special steel as claimed in claim 1, wherein: 65-70% of electro-fused corundum, 6-7% of mullite, 8-10% of glass fiber and 15% of silicon nitride.
4. The anti-clogging submerged nozzle for continuous casting of special steel according to claim 2, wherein: the grain diameter of aluminum nitride in the heat conducting layer is 3-5 mu m.
5. The anti-clogging submerged nozzle for continuous casting of special steel as claimed in claim 1, wherein: the mixing amount of the adhesive is 12-13%, and the mixing amount of the adhesive is 12-13%.
6. The anti-clogging submerged nozzle for continuous casting of special steel as claimed in claim 1, wherein: the thickness ratio of the heat conduction layer to the heat insulation layer is 1 (2-3).
7. A method for preparing an anti-clogging submerged nozzle for continuous casting of special steel as claimed in any one of claims 1 to 6, characterized by: the method comprises the following steps:
preparing raw materials in the heat conducting layer and the heat insulating layer, grinding and crushing the raw materials to be less than 150 meshes, and sieving for later use;
mixing the raw materials according to the formula to obtain a heat conducting layer and a heat insulating layer respectively, adding an adhesive into the heat conducting layer according to the formula, adding the adhesive into the heat insulating layer, and pressing into a green brick under the pressure of 50-100 MPa;
heating the green bricks to 600-700 ℃ under nitrogen atmosphere, and preserving heat and calcining for 2-3 h; and then heating to 1660-1800 ℃ and preserving heat for secondary calcination for 2-4 h to obtain the finished product of the submerged nozzle.
8. The method for preparing the anti-blocking submerged nozzle for continuous casting of special steel according to claim 7, wherein the secondary calcination temperature of the green brick is 1700-1750 ℃, and the heat preservation calcination is carried out for 2-3 h.
CN202310021027.8A 2023-01-07 2023-01-07 Anti-blocking submerged nozzle for special steel continuous casting and preparation method thereof Pending CN116274985A (en)

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