CN110922214B - Coating material for preventing submerged nozzle from nodulation and preparation method thereof - Google Patents
Coating material for preventing submerged nozzle from nodulation and preparation method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
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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
- B22D41/50—Pouring-nozzles
- B22D41/52—Manufacturing or repairing thereof
- B22D41/54—Manufacturing or repairing thereof characterised by the materials used therefor
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/51—Metallising, e.g. infiltration of sintered ceramic preforms with molten metal
- C04B41/515—Other specific metals
- C04B41/5155—Aluminium
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Abstract
The invention discloses a coating material for preventing an immersion nozzle from nodulation and a preparation method thereof, belonging to the technical field of coating materials of immersion nozzles. The invention comprises the following components in percentage by weight: fine mullite powder: 20-56 parts of corundum fine powder: 15-23 parts of Guangxi white mud: 4-8 parts of activated alumina micropowder: 7-18 parts of aluminum dihydrogen phosphate: 5-8 parts of fluxing agent: 8-12 parts of an antioxidant: 2-11 parts of dispersant: 0.3 to 2.0 parts. The invention aims to solve the problems that an immersion nozzle is easy to bake and oxidize and is blocked by nodulation substances in the prior art, and provides a coating material for preventing the submerged nozzle from nodulation and a preparation method thereof, which not only can achieve the purposes of preventing the submerged nozzle from baking and oxidizing and preventing air from entering molten steel through the nozzle in the using process, but also can prevent the submerged nozzle from nodulation and blocking.
Description
Technical Field
The invention relates to the technical field of coating materials of submerged nozzles, in particular to a coating material for preventing submerged nozzles from nodulation and a preparation method thereof.
Background
At present, Al is generally used in continuous casting2O3-C and Al2O3-ZrO2the-C submerged nozzle can be directly oxidized with air in the baking or using process, so that the product has loose structure, reduced strength and large potential safety hazard, and the service life is influenced. Meanwhile, when molten steel passes through the inner wall of the nozzle, the surface of the inner wall is decarburized to form an uneven porous structure, the molten steel can generate local stagnation of molten steel flow on the surface layer, and when steel types such as aluminum killed steel and the like are poured, an easily-oxidizable element Al and the like in the molten steel can be generated into an oxidation product Al2O3More easily adhere to on the mouth of a river inner wall, make mouth of a river hole jam, cause the mouth of a river to hold and flow to because the attachment drops and can form a large amount of non-metallic inclusions in getting into the molten steel, thereby produce the product defect.
In order to solve the problem of the clogging of the submerged nozzle nubbles, two methods are generally adopted in the industry at present: one is to compound a layer of carbon-free or silicon-free material lining on the inner wall of the water gap to prevent blockage, but the process is complex and the cost is higher; the other is that the coating technology is generally arranged on the outer wall of the water gap to prevent the surface of the water gap from being oxidized and prevent air from permeating into the inner wall of the water gap through the pores of the refractory material, but the effect of preventing the inner wall of the submerged water gap from nodulation is not obvious. Therefore, how to solve the problems of baking oxidation and clogging of the submerged nozzle is a constantly pursued goal in the industry.
Through search, a large number of patents have been published on coating materials for submerged entry nozzles, such as chinese patent application No.: 2016200481078, the name of invention creation is: the utility model provides an anti immersion nozzle that corrodes, this application discloses an anti immersion nozzle that corrodes, including the mouth of a river body, the inside runner that is used for the molten steel circulation of seting up of mouth of a river body, mouth of a river body surface is provided with anti erosion coating, and anti erosion coating sets up in the slag line position of mouth of a river body. The advantage is that this anti erosion coating can realize the same anti erosion effect with former zirconia bed of material, and the cooperation zirconia layer is used, can improve life. But the cost is higher, and the slag line part arranged on the outer wall of the water gap can not play a role in preventing accretion.
Also as in chinese patent application No.: 2016101596961, the name of invention creation is: the application discloses a shrink-proof glaze protective coating for a submerged nozzle slag line and a preparation method thereof. Although the anti-shrinkage glaze protective coating can improve the strength and the erosion resistance of the submerged nozzle slag line, the anti-shrinkage glaze protective coating cannot play a role in preventing accretion due to the fact that the anti-shrinkage glaze protective coating is arranged on the slag line on the outer wall of the nozzle.
Again, as with chinese patent application No.: 2018103575530, the name of invention creation is: the scheme describes a graphite oxidation resistant coating prepared by using single-layer/double-layer alumina, alumina and siliceous or magnesia-alumina spinel and other main raw materials and adding aluminum dihydrogen phosphate as a binder. The coating has the advantages that the high-temperature performance is excellent, the compactness of the coating is improved through reasonable gradation, the strength of the coating is improved by adding aluminum dihydrogen phosphate, but the coating has the defects of higher cost and poorer thermal shock stability, and a sufficient glass phase cannot be formed when the coating is baked at a water gap of 700-1100 ℃, so that the using effect of the coating is reduced.
None of the above solutions is lost to a good search for coating materials for submerged entry nozzles, but there is still room for further improvement, and research on coating materials for submerged entry nozzles in the industry has never been stopped.
Disclosure of Invention
1. Technical problem to be solved by the invention
The invention aims to solve the problems that an immersion nozzle is easy to bake and oxidize and is blocked by nodulation substances in the prior art, and provides a coating material for preventing the submerged nozzle from nodulation and a preparation method thereof, which not only can achieve the purposes of preventing the submerged nozzle from baking and oxidizing and preventing air from entering molten steel through the nozzle in the using process, but also can prevent the submerged nozzle from nodulation and blocking.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
the invention relates to a coating material for preventing a submerged nozzle from nodulation, which comprises the following raw materials in percentage by weight: fine mullite powder: 20-56 parts of corundum fine powder: 15-23 parts of Guangxi white mud: 4-8 parts of activated alumina micropowder: 7-18 parts of aluminum dihydrogen phosphate: 5-8 parts of fluxing agent: 8-12 parts of an antioxidant: 2-11 parts of dispersant: 0.3 to 2.0 parts.
As a further improvement of the invention, the fluxing agent is a mixture of waste glass powder, potash feldspar and boron clinker, wherein the amount of waste glass powder is as follows: the total dosage of the potash feldspar and the boron frit is (2-4): 1.
As a further improvement of the invention, the grain diameter of the mullite fine powder is less than or equal to 0.088mm, wherein Al in the mullite fine powder2O3The content of (A) is 60wt% -90 wt%.
As a still further improvement of the present invention,the grain size of the corundum fine powder is less than or equal to 0.075mm, wherein Al in the corundum fine powder2O3The content of (A) is more than or equal to 96 wt%.
As a further improvement of the invention, the particle size of the Guangxi white mud is less than or equal to 0.075mm, wherein Al in the Guangxi white mud2O3The content of (A) is 30wt% -35 wt%, SiO2The content of (A) is 49wt% -50 wt%.
As a further improvement of the invention, the particle size of the activated alumina micro powder is less than or equal to 2 mu m, wherein Al in the activated alumina micro powder2O3The content of (A) is more than or equal to 99 wt%.
As a further improvement of the invention, P in the aluminium dihydrogen phosphate2O5The content of (A) is 37wt% -43 wt%, Al2O3The content is 36wt% -45 wt%, and the pH value of the aluminum dihydrogen phosphate is 1.5-4.5.
As a further improvement of the invention, the antioxidant is a mixture of at least one of silicon carbide or silicon nitride and aluminum powder and silicon powder, the particle size is less than or equal to 0.075mm, wherein the dosage of the aluminum powder is as follows: the amount of the silicon powder is 1 (3-4).
The invention relates to a preparation method of a coating for preventing a submerged nozzle from nodulation, which comprises the following steps:
a. mixing materials: putting mullite fine powder, corundum fine powder, Guangxi white mud, active alumina micro powder, a fluxing agent, a dispersing agent and an antioxidant into water with the temperature of 35-70 ℃, uniformly mixing, adding aluminum dihydrogen phosphate, stirring for 5-10 min, uniformly stirring to obtain a mixture, and finally grinding the mixture for 2-3 h to obtain slurry;
b. construction: b, adopting a negative pressure dipping mode to make the slurry obtained in the step a adhere to the inner wall of the submerged nozzle, wherein the thickness of the coating is 1-2 mm;
c. and (3) drying: and d, drying the coating obtained in the step b at the temperature of between 90 and 110 ℃ for 2 to 3 hours to prepare the coating for preventing the submerged nozzle from nodulation.
As a further improvement of the present invention, the step of negative pressure impregnation is as follows:
(1) cleaning the inner wall surface of the submerged nozzle by using compressed air, horizontally placing the submerged nozzle into the impregnation tank, and covering the top end cover of the impregnation tank;
(2) pumping the impregnation tank to vacuum;
(3) pumping the slurry into the dipping tank through a feed pipe by using a feed pump until the liquid level of the slurry in the dipping tank reaches 8-12 cm above the highest plane of the submerged nozzle;
(4) vacuumizing again to below-0.098 MPa, and maintaining the pressure for at least 10 min;
(5) closing the vacuum-pumping valve, slowly opening the pressure release valve to restore the current air atmosphere in the immersion liquid groove, and standing the immersion type water gap for at least 30min under the atmospheric pressure until the inner wall surface of the immersion type water gap is fully saturated and immersed.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) the coating material for preventing the submerged nozzle from nodulation mainly takes mullite fine powder, corundum fine powder, Guangxi white mud, quartz powder, activated alumina micro powder and the like as main raw materials, aluminum dihydrogen phosphate is used as a bonding agent, and a fluxing agent, a dispersing agent and an antioxidant are added, so that the prepared coating has good adhesion performance and oxidation resistance. Because the raw material part adopts the mullite fine powder, the property of the mullite is stable, the melting point of the mullite is 1850 ℃, the raw material cost of the whole coating material can be reduced, and the thermal shock stability and the high-temperature performance of the submerged nozzle coating are improved. The anti-nodulation coating of immersion nozzle sets up at immersion nozzle inner wall, not only can prolong immersion nozzle's life, improves immersion nozzle's continuous casting time, can also reach the purpose that reduces nodulation thickness.
(2) The invention relates to a coating material for preventing a submerged nozzle from nodulation, wherein a fluxing agent is a mixture of waste glass powder, potassium feldspar and boron frit, and the dosage of the waste glass powder is as follows: the total dosage ratio of the potassium feldspar to the boron frit is (2-4): 1, the temperature and the range of a formed coating can be adjusted by introducing the waste glass powder, the boron frit and the potassium feldspar for matched use, the strength is high, the oxidation resistance is excellent, and the shrinkage generated during the firing of part of Guangxi white mud and the melting of a fluxing agent can be counteracted by adding the waste glass powder. The coating is in a high-viscosity molten state within the temperature range of 700-1200 ℃, plays a role in isolating air, thereby preventing the immersion nozzle from being oxidized in the baking and using processes and being capable of completely replacing the surface antioxidant coating of the immersion nozzle. When the submerged nozzle is used, the inner wall coating of the submerged nozzle is melted at high temperature to form a compact liquid glass layer, the hole cracks of the inner wall of the submerged nozzle are sealed, the submerged nozzle is prevented from being baked and oxidized, further surface decarburization is caused, pits, cracks and the like are formed, usually molten steel is easy to form nodules, and the nodules are caused mainly because the temperature of the inner surface of the nozzle is lower than that of the molten steel, the molten steel is easy to form cold steel, and further the nodules are generated.
(3) The coating material for preventing the submerged nozzle from nodulation is prepared from more than one of aluminum powder, silicon powder and silicon carbide or silicon nitride as an antioxidant, wherein the particle size is less than or equal to 0.075mm, and the dosage of the aluminum powder is as follows: the dosage ratio of the silicon powder is 1 (3-4). By adding special antioxidant such as aluminum powder, silicon powder and mixture of more than one of silicon nitride or silicon carbide as antioxidant, the antioxidant property of the coating is improved, and simultaneously, the coating can play a good anti-caking effect.
(4) According to the preparation method of the coating for preventing the submerged nozzle from nodulation, the coating is arranged in a reduced pressure dipping mode, so that compared with the traditional brushing mode, the labor intensity can be obviously reduced, the coating is saved, the adhesion effect of the coating on the inner wall surface of the submerged nozzle can be improved, and the phenomenon of coating falling and cracking is avoided.
Drawings
FIG. 1 is a schematic view of the process of negative pressure impregnation in the present invention.
Detailed Description
For a further understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The present invention will be further described with reference to the following examples.
Example 1
The coating material for preventing the submerged nozzle from nodulation comprises the following raw materials in parts by weight: fine mullite powder: 20, corundum fine powder: 15, Guangxi white mud: 4, activated alumina micropowder: 7, aluminum dihydrogen phosphate: 5, fluxing agent: 8, antioxidant: 2, dispersing agent: 0.3. the coating material mainly takes mullite fine powder, corundum fine powder, Guangxi white mud, quartz powder, active alumina micro powder and the like as main raw materials, aluminum dihydrogen phosphate is used as a bonding agent, and a fluxing agent, a dispersing agent and an antioxidant are added at the same time, so that the prepared coating has good adhesion performance and oxidation resistance. Because the raw material part adopts the mullite fine powder, the property of the mullite is stable, the melting point of the mullite is 1850 ℃, the raw material cost of the whole coating material can be reduced, and the thermal shock stability and the high-temperature performance of the submerged nozzle coating are improved.
The fluxing agent of the embodiment is a mixture of waste glass powder, potassium feldspar and boron clinker, and the dosage of the waste glass powder is as follows: the total dosage ratio of the potassium feldspar to the boron clinker is 2:1, the potassium feldspar is added to reduce the viscosity and keep the fluidity, the boron clinker is added to improve the viscosity, the viscosity of the coating during baking can be adjusted by the potassium feldspar and the boron clinker, the content of the potassium feldspar and the boron clinker is adjusted according to actual conditions, the potassium feldspar and the boron clinker are also kept at a certain viscosity at a high temperature, the coating is not easy to fall off and crack, and the coating can be prevented from being oxidized. The waste glass powder, the boron frit and the potassium feldspar are introduced to be matched for use, so that the temperature and the range of the formed coating can be adjusted, the strength is high, the oxidation resistance is excellent, and the shrinkage generated when part of Guangxi white mud is sintered and the fluxing agent is melted can be offset by adding the waste glass powder. The coating is in a high-viscosity molten state within the temperature range of 700-1200 ℃, plays a role in isolating air, thereby preventing the immersion nozzle from being oxidized in the baking and using processes and being capable of completely replacing the surface antioxidant coating of the immersion nozzle. When the submerged nozzle is used, the inner wall coating of the submerged nozzle is melted at high temperature to form a compact liquid glass layer, the hole cracks of the inner wall of the submerged nozzle are sealed, the submerged nozzle is prevented from being baked and oxidized, further surface decarburization is caused, pits, cracks and the like are formed, usually molten steel is easy to form nodules, and the nodules are caused mainly because the temperature of the inner surface of the nozzle is lower than that of the molten steel, the molten steel is easy to form cold steel, and further the nodules are generated. In the embodiment, the waste glass powder, the potassium feldspar and the boron frit are used as the fluxing agent, so that the melting range of the coating can be adjusted to 700-1200 ℃ which is larger than the actual baking temperature range of 700-1100 ℃, and further the surface nodulation of the nozzle is reduced, and the larger the melting temperature range of the coating is, the wider the temperature range of the coating is.
The grain size of the mullite fine powder in the embodiment is less than or equal to 0.088mm, wherein Al in the mullite fine powder2O3The content of (A) is 60wt% -90 wt%.
The grain size of the corundum fine powder of the present example is not more than 0.075mm, wherein Al is in the corundum fine powder2O3The content of (A) is more than or equal to 96 wt%.
The particle size of the Guangxi white mud is less than or equal to 0.075mm, wherein Al in the Guangxi white mud2O3The content of (A) is 30wt% -35 wt%, SiO2The content of (A) is 49wt% -50 wt%.
The particle size of the activated alumina micro powder of the embodiment is less than or equal to 2 μm, wherein Al in the activated alumina micro powder2O3The content of (A) is more than or equal to 99 wt%.
P in the aluminum dihydrogen phosphate of this example2O5The content of (A) is 37wt% -43 wt%, Al2O3The content is 36wt% -45 wt%, and the pH value of the aluminum dihydrogen phosphate is 1.5-4.5. The dispersant is a mixture of carboxymethyl cellulose, hydroxyethyl cellulose and sodium tripolyphosphate. Aluminum dihydrogen phosphate is used as a bonding agent, and hydroxyethyl cellulose, sodium tripolyphosphate, carboxymethyl cellulose and the like are added as dispersing agents, so that the aluminum dihydrogen phosphate-containing composite material not only canThe construction performance and the adhesion performance of the coating material can be improved, the high-temperature oxidation resistance of the coating can be improved, and the coating material with excellent high-temperature performance can be obtained. Specifically, hydroxyethyl cellulose is used as a dispersant in this embodiment.
The antioxidant in the embodiment is a mixture of more than one of aluminum powder, silicon powder and silicon carbide or silicon nitride, the particle size is less than or equal to 0.075mm, wherein the aluminum powder is used in an amount of: the dosage ratio of the silicon powder is 1: 3. By adding special antioxidant such as aluminum powder, silicon powder and mixture of more than one of silicon nitride or silicon carbide as antioxidant, the antioxidant property of the coating is improved, and simultaneously, the coating can play a good anti-caking effect.
The preparation method of the coating for preventing the submerged nozzle from nodulation in the embodiment comprises the following steps:
a. mixing materials: putting mullite fine powder, corundum fine powder, Guangxi white mud, active alumina micro powder, a fluxing agent, a dispersing agent and an antioxidant into water with the temperature of 35 ℃ for uniform mixing, adding aluminum dihydrogen phosphate, stirring for 5-10 min by using a stirrer, uniformly stirring to obtain a mixture, and finally ball-milling for 2-3 h by using a ball mill to obtain slurry;
b. construction: b, adopting a negative pressure dipping mode to enable the slurry obtained in the step a to be attached to the inner wall of the submerged nozzle, wherein the thickness of the coating is 1 mm; the anti-accretion coating is arranged on the inner wall of the immersion nozzle, so that the service life of the immersion nozzle can be prolonged, the continuous casting time of the immersion nozzle is prolonged, and the purpose of reducing the accretion thickness can be achieved.
As shown in fig. 1, the steps of the negative pressure impregnation in this embodiment are as follows: (1) cleaning the inner wall surface of the submerged nozzle by using compressed air, horizontally placing the submerged nozzle into the impregnation tank, and covering the top end cover of the impregnation tank; (2) pumping the impregnation tank to vacuum; (3) pumping the slurry into the impregnation tank through a feed pipe by using a feed pump until the liquid level of the slurry in the impregnation tank reaches 8cm above the highest plane of the submerged nozzle; (4) vacuumizing again to-0.098 MPa, and maintaining the pressure for 10 min; (5) closing the vacuum-pumping valve, slowly opening the pressure release valve to restore the current air atmosphere in the immersion tank, standing the immersion nozzle for 30min under the atmospheric pressure, and fully saturating and immersing the inner wall surface of the immersion nozzle. The mode that adopts decompression flooding sets up the coating, compares with traditional brush mode and can obviously reduce intensity of labour, saves coating, can also improve the adhesion effect of coating on immersion nozzle inner wall surface, avoids appearing the phenomenon that the coating drops the fracture.
c. And (3) drying: and d, drying the coating obtained in the step b at 90 ℃ for 2h to prepare the coating for preventing the submerged nozzle from nodulation.
Example 2
The coating material for preventing the clogging of the submerged nozzle of the present embodiment is substantially the same as that of embodiment 1 except that: 24 parts of mullite fine powder, 20 parts of corundum fine powder, 8 parts of Guangxi white mud, 17 parts of active alumina micro powder, 7 parts of dihydrogen phosphate, 7.5 parts of waste glass powder, 1.5 parts of potassium feldspar, 1 part of boron frit, 1 part of aluminum powder, 3 parts of silicon powder, 6 parts of silicon carbide and 2 parts of carboxymethyl cellulose.
The preparation method of a coating for preventing the clogging of a submerged nozzle in this embodiment is substantially the same as that of embodiment 1, except that: in the material mixing step: putting mullite fine powder, corundum fine powder, Guangxi white mud, active alumina micro powder, a fluxing agent, a dispersing agent and an antioxidant into water with the temperature of 70 ℃ for uniform mixing, adding aluminum dihydrogen phosphate, stirring for 5min by using a stirrer, uniformly stirring to obtain a mixture, and finally ball-milling for 3h by using a ball mill to obtain slurry. And (3) adopting a negative pressure dipping mode to make the slurry adhere to the inner wall surface of the submerged nozzle, and drying the coating for 3 h. Specifically, the thickness of the coating layer on the inner wall of the submerged nozzle in this embodiment is 2 mm. Production statistics show that continuous casting time of the submerged nozzle is prolonged to 10 hours from the original average 6 hours when steel is produced by using the coating technology, and the average nodulation thickness is reduced by 25%.
As shown in fig. 1, the steps of the negative pressure impregnation in this embodiment are as follows: (1) cleaning the inner wall surface of the submerged nozzle by using compressed air, horizontally placing the submerged nozzle into the impregnation tank, and covering the top end cover; (2) pumping the impregnation tank to vacuum; (3) pumping the slurry into the dipping tank through a feed pipe by using a feed pump until the liquid level of the slurry in the dipping tank reaches 12cm above the highest plane of the submerged nozzle; (4) vacuumizing again to-0.1 MPa, and maintaining the pressure for 15 min; (5) closing the vacuum-pumping valve, slowly opening the pressure release valve to restore the current air atmosphere in the immersion tank, and standing the submerged nozzle for 40min under the atmospheric pressure until the inner wall surface of the submerged nozzle is fully saturated and immersed. The mode that adopts decompression flooding sets up the coating, compares with traditional brush mode and can obviously reduce intensity of labour, saves coating, can also improve the adhesion effect of coating on immersion nozzle inner wall surface, avoids appearing the phenomenon that the coating drops the fracture.
c. And (3) drying: and (c) drying the coating obtained in the step (b) at 110 ℃ for 3h to prepare the coating for preventing the submerged nozzle from nodularizing.
Example 3
The coating material for preventing the clogging of the submerged nozzle of the present embodiment is substantially the same as that of embodiment 1 except that: 56 parts of mullite fine powder, 23 parts of corundum fine powder, 8 parts of Guangxi white mud, 18 parts of active alumina micro powder, 5 parts of aluminum dihydrogen phosphate, 6 parts of waste glass powder, 2 parts of potassium feldspar, 1 part of boron frit, 0.5 part of aluminum powder, 1.5 parts of silicon nitride fine powder and 1 part of hydroxyethyl cellulose.
The preparation method of a coating for preventing the clogging of a submerged nozzle in this embodiment is substantially the same as that of embodiment 1, except that: in the material mixing step: putting mullite fine powder, corundum fine powder, Guangxi white mud, active alumina micro powder, a fluxing agent, a dispersing agent and an antioxidant into water with the temperature of 60 ℃ for uniform mixing, adding aluminum dihydrogen phosphate, stirring for 10min by using a stirrer, uniformly stirring to obtain a mixture, and finally ball-milling for 2h by using a ball mill to obtain slurry. And (3) adopting a negative pressure dipping mode to make the slurry adhere to the inner wall surface of the submerged nozzle, and drying the coating for 2h for use. Specifically, the thickness of the coating layer on the inner wall of the submerged nozzle in this embodiment is 2 mm. Production statistics show that continuous casting time of the submerged nozzle is prolonged to 10 hours from the original average 6 hours when steel is produced by using the coating technology, and the average nodulation thickness is reduced by 25%.
As shown in fig. 1, the steps of the negative pressure impregnation in this embodiment are as follows: (1) cleaning the inner wall surface of the submerged nozzle by using compressed air, horizontally placing the submerged nozzle into the impregnation tank, and covering the top end cover; (2) pumping the impregnation tank to vacuum; (3) pumping the slurry into the dipping tank through a feed pipe by using a feed pump until the liquid level of the slurry in the dipping tank reaches 10cm above the highest plane of the submerged nozzle; (4) vacuumizing again to-0.12 MPa, and maintaining the pressure for 25 min; (5) closing the vacuum-pumping valve, slowly opening the pressure release valve to restore the current air atmosphere in the immersion tank, standing the immersion nozzle for 45min under the atmospheric pressure, and fully saturating and immersing the inner wall surface of the immersion nozzle. The mode that adopts decompression flooding sets up the coating, compares with traditional brush mode and can obviously reduce intensity of labour, saves coating, can also improve the adhesion effect of coating on immersion nozzle inner wall surface, avoids appearing the phenomenon that the coating drops the fracture.
c. And (3) drying: and d, drying the coating obtained in the step b at 100 ℃ for 3 hours to prepare the coating for preventing the submerged nozzle from nodulation.
According to the proportion, the solid raw materials are weighed and stirred, and then poured into a stirrer; adding appropriate amount of water at 70 deg.C, mixing, adding aluminum dihydrogen phosphate, and stirring. The viscosity of the coating is 2846 mPas, the prepared coating is dipped to enable the slurry to be attached to the inner wall surface of the submerged nozzle, and the coating is dried for 3 hours and then used. The thickness of the coating is 1mm, and the coating still has good adhesive property and does not have the phenomena of peeling or cracking after being heated at the high temperature of 800 ℃ for 3.0 h.
Example 4
The coating material for preventing the submerged nozzle from nodulation of the embodiment comprises the following components in parts by weight: 40 parts of mullite fine powder, 20 parts of corundum fine powder, 6 parts of Guangxi white mud, 12 parts of active alumina micro powder, 6 parts of aluminum dihydrogen phosphate, 6.5 parts of waste glass powder, 0.5 part of potassium feldspar, 1.5 parts of boron frit, 0.7 part of aluminum powder, 2.8 parts of silicon powder, 3.5 parts of silicon carbide fine powder and 1 part of sodium tripolyphosphate.
According to the proportion, the solid raw materials are weighed and stirred, and then poured into a stirrer; adding appropriate amount of water at 35 deg.C, mixing, adding aluminum dihydrogen phosphate, and stirring. And (3) adopting a negative pressure dipping mode to make the slurry adhere to the inner wall surface of the submerged nozzle, and drying the coating for 3 h. The coating has a thickness of 2mm, and still has good adhesion performance without peeling or cracking when baked at 1050 ℃ for 3 hours.
Comparative example 1
The average thickness of the submerged nozzle nodules is about 2.7mm when the coatings are not arranged, and is reduced to 1.1mm after the coatings are arranged, so that the control requirement of the site can be met, the flaw detection alarm rate of subsequent finished products is obviously reduced, and the specific measurement results are shown in the following table 1.
TABLE 1 average thickness of submerged entry nozzle accretion/mm
The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.
Claims (7)
1. A coating material for preventing the accretion of a submerged entry nozzle, characterized in that: the paint comprises the following components in parts by weight: fine mullite powder: 20-56 parts of corundum fine powder: 15-23 parts of Guangxi white mud: 4-8 parts of activated alumina micro powder: 7-18 parts of aluminum dihydrogen phosphate: 5-8 parts of a fluxing agent: 8-12 parts of an antioxidant: 2-11 parts of a dispersant: 0.3-2.0 parts; wherein the fluxing agent is a mixture of waste glass powder, potassium feldspar and boron frits, wherein the dosage of the waste glass powder is as follows: the total dosage of the potassium feldspar and the boron frit is (2-4): 1; the antioxidant is a mixture of at least one of silicon carbide or silicon nitride and aluminum powder and silicon powder, the particle size is less than or equal to 0.075mm, wherein the aluminum powder dosage is as follows: the amount of the silicon powder is 1 (3-4).
2. The coating material for preventing clogging of a submerged entry nozzle according to claim 1, wherein: the grain diameter of the mullite fine powder is less than or equal to 0.088mm, wherein Al in the mullite fine powder2 O3 The content of (B) is 60wt% -90 wt%.
3. The coating material for preventing clogging of a submerged entry nozzle according to claim 1, wherein: the grain size of the corundum fine powder is less than or equal to 0.075mm, wherein Al in the corundum fine powder2 O3 The content of (A) is more than or equal to 96 wt%.
4. The coating material for preventing clogging of a submerged entry nozzle according to claim 1, wherein: the particle size of Guangxi white mud is less than or equal to 0.075mm, wherein Al in Guangxi white mud2 O3 The content of (A) is 30wt% -35 wt%, SiO2 The content of (A) is 49wt% to 50 wt%.
5. The coating material for preventing clogging of a submerged entry nozzle according to claim 1, wherein: the grain diameter of the active alumina micro powder is less than or equal to 2 mu m, wherein Al in the active alumina micro powder2 O3 The content of (A) is more than or equal to 99 wt%.
6. The coating material for preventing clogging of a submerged entry nozzle according to claim 1, wherein: aluminum dihydrogen phosphate inner P2 O5 37-43 wt% of Al2 O3 The content is 36wt% -45 wt%, and the pH value of the aluminum dihydrogen phosphate is 1.5-4.5.
7. The method for preparing a coating material for preventing the clogging of a submerged entry nozzle according to claim 1, wherein: the method comprises the following steps:
a. mixing materials: putting mullite fine powder, corundum fine powder, Guangxi white mud, active alumina micro powder, a fluxing agent, a dispersing agent and an antioxidant into water at the temperature of 35-70 ℃, uniformly mixing, adding aluminum dihydrogen phosphate, stirring for 5-10 min, uniformly stirring to obtain a mixture, and finally grinding the mixture for 2-3 h to obtain slurry;
b. construction: b, adopting a negative pressure dipping mode to enable the slurry obtained in the step a to be attached to the inner wall of the submerged nozzle, wherein the thickness of the coating is 1 mm-2 mm; the negative pressure impregnation comprises the following steps:
(1) cleaning the inner wall surface of the submerged nozzle by using compressed air, horizontally placing the submerged nozzle into the impregnation tank, and covering the top end cover of the impregnation tank;
(2) pumping the impregnation tank to vacuum;
(3) pumping the slurry into the dipping tank through a feed pipe by using a feed pump until the liquid level of the slurry in the dipping tank reaches 8-12 cm above the highest plane of the submerged nozzle;
(4) vacuumizing again to below-0.098 MPa, and maintaining the pressure for at least 10 min;
(5) closing the vacuum-pumping valve, slowly opening the pressure release valve to restore the current air atmosphere in the immersion tank, and standing the submerged nozzle for at least 30min under the atmospheric pressure until the inner wall surface of the submerged nozzle is fully saturated and immersed;
c. and (3) drying: and d, drying the coating obtained in the step b at the temperature of 90-110 ℃ for 2-3 h to prepare the coating for preventing the submerged nozzle from nodulation.
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| CN112159241B (en) * | 2020-10-09 | 2021-06-22 | 邢台德勤工矿工程有限公司 | Corundum-aluminosilicate composite refractory material and preparation method and application thereof |
| CN112876264A (en) * | 2021-01-13 | 2021-06-01 | 广东韶钢松山股份有限公司 | Application method of continuous casting machine immersion type water gap sealing material |
| CN113999023B (en) * | 2021-09-28 | 2022-11-25 | 赛文斯新型材料(无锡)有限公司 | Preparation method of nano refractory material for stopper rod |
| CN114716850B (en) * | 2022-04-22 | 2023-06-02 | 钢铁研究总院有限公司 | Nozzle coating for rare earth steel continuous casting and preparation method thereof |
| CN114773045B (en) * | 2022-04-22 | 2023-03-03 | 钢铁研究总院有限公司 | Magnesium-silicon coating for rare earth steel continuous casting nozzle and preparation method thereof |
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| KR100961329B1 (en) * | 2007-12-21 | 2010-06-04 | 주식회사 포스코 | Submerged entry nozzle having coating layer for preventing clogging of submerged entry nozzle |
| CN101712559A (en) * | 2009-05-25 | 2010-05-26 | 上海宝明耐火材料有限公司 | Water gap lining layer material for continuous casting |
| CN101935231B (en) * | 2010-08-24 | 2012-10-10 | 中钢集团洛阳耐火材料研究院有限公司 | Preparation method of compound refractory kiln furniture |
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| CN105693289B (en) * | 2016-03-21 | 2018-05-29 | 河南省西保冶材集团有限公司 | A kind of submersed nozzle slag line shrinkproof glaze protective coating and preparation method thereof |
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