A material for continuous casting nozzle and a method for manufacturing the same

Abstract

The application relates to the technical field of continuous casting functional nozzle materials, and discloses a continuous casting functional nozzle material and a preparation method thereof. The continuous casting functional nozzle material comprises the following components in parts by weight: corundum 40-50 parts, metallic silicon 5-8 parts, glucose or malt dextrin 5-10 parts, urea 0.5-1 part and functional additives 4-6 parts. The functional additives comprise the following raw materials in parts by weight: anorthite 1-10 parts and mullite-coated aluminum titanate 1-10 parts. Through the technical scheme, the problem of insufficient thermal shock resistance and low strength of the continuous casting functional nozzle material in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of continuous casting functional nozzle materials, specifically to a material for continuous casting functional nozzles and its preparation method. Background Technology

[0002] In continuous casting of steel, the functional nozzle is a core component connecting the tundish and the crystallizer. It is primarily used to precisely control the molten steel flow rate, stably guide the molten steel flow pattern, isolate air to prevent secondary oxidation of the molten steel, and effectively avoid slag entrapment. The comprehensive performance of its material directly affects the surface quality, internal purity, and continuity and stability of continuous casting production. Currently, the most widely used materials for functional nozzles in industrial continuous casting are carbon-bonded refractories such as alumina-carbon and zirconium-carbon. These materials, with their good high-temperature resistance and certain corrosion resistance, can meet the basic operating requirements of continuous casting production. However, in practical applications, they still suffer from insufficient thermal shock resistance and low strength, which limits their service life and application effectiveness.

[0003] In continuous casting, functional nozzles frequently experience rapid temperature fluctuations from room temperature to over 1500℃. Traditional materials, with their high coefficients of thermal expansion and low thermal conductivity, are prone to microcracks due to thermal stress concentration. These cracks can propagate and cause the nozzle to burst and fail. Furthermore, under the influence of high-speed molten steel, static pressure, and mechanical impacts and vibrations during operation, materials with insufficient strength are susceptible to wear, spalling, and even breakage, leading to premature nozzle failure and frequent downtime for replacement. This not only increases refractory material consumption and production costs, and reduces production efficiency, but also risks quality defects such as molten steel leakage and inclusions in the cast billet due to nozzle damage. This makes it difficult to meet the demands of current continuous casting processes that are moving towards higher casting speeds, longer casting runs, and higher quality. Therefore, it is necessary to develop materials for continuous casting functional nozzles that address both thermal shock resistance and strength issues. Summary of the Invention

[0004] This invention proposes a material for continuous casting functional nozzles and its preparation method, which solves the problems of insufficient thermal shock resistance and low strength of materials for continuous casting functional nozzles in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a material for a continuous casting functional nozzle, comprising the following components in parts by weight: 40-50 parts corundum, 5-8 parts metallic silicon, 5-10 parts glucose or maltodextrin, 0.5-1 part urea, and 4-6 parts functional additives; The functional additives include the following raw materials in parts by weight: 1-10 parts of calcium feldspar and 1-10 parts of mullite-coated aluminum titanate.

[0006] In this invention, glucose or maltodextrin and urea are used as organic binders added to the material for continuous casting functional nozzles, which has the advantages of low cost and better binding effect.

[0007] As a further technical solution, the mass ratio of the calcium feldspar and mullite-coated aluminum titanate is 1:4 to 4:1.

[0008] As a further technical solution, the preparation method of the mullite-coated aluminum titanate includes the following steps: Aluminum titanate is activated to obtain pretreated aluminum titanate; The pretreated aluminum titanate was added to mullite sol, mixed, dried, calcined, and ground to obtain mullite-coated aluminum titanate.

[0009] As a further technical solution, the mass of the pretreated aluminum titanate is 25% to 35% of the mass of the mullite sol.

[0010] As a further technical solution, the calcination includes a first calcination and a second calcination; The temperature of the first calcination is 580~620℃, and the time is 25~40min; The second calcination is carried out at a temperature of 1500~1550℃ for 2~3 hours.

[0011] As a further technical solution, the particle size of the anorthite is 2~4μm; the particle size of the aluminum titanate is 0.5~1μm.

[0012] As a further technical solution, the concentration of the mullite sol is 0.20~0.28 g / L.

[0013] This invention also proposes a method for preparing a material for a continuous casting functional nozzle, comprising the following steps: Alumina, metallic silicon, and functional additives are mixed, and glucose or maltodextrin and urea are added. The mixture is then granulated, dried, shaped, and sintered to obtain a material for continuous casting functional nozzles.

[0014] As a further technical solution, the sintering temperature is 1100~1150℃ and the time is 20~25h.

[0015] The working principle and beneficial effects of this invention are as follows: In this application, the material for continuous casting functional nozzles is based on corundum as the main component. Through the synergistic effect of functional additives (calcium feldspar and mullite-coated aluminum titanate), the thermal shock resistance and strength of the material are significantly improved. The mullite-coated layer, combined with calcium feldspar, can effectively inhibit the thermal expansion of aluminum titanate, reduce the overall thermal expansion coefficient of the material, and buffer thermal stress by utilizing the difference in thermal conductivity among the three components, thereby reducing microcracks caused by alternating high and low temperatures during continuous casting. Glucose or maltodextrin, urea, corundum, and functional additives form a dense bond structure, enhancing the bonding force between components. Combined with the supporting effect of the coating layer, this improves the overall strength of the material, ultimately resulting in a significant improvement in the material's thermal shock resistance and strength. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] In the following examples and comparative examples, the corundum is fused alumina, which is composed of coarse particles and fine powder in a mass ratio of 2:1, with an average particle size of 0.8 mm for the coarse particles and an average particle size of 45 μm for the fine powder; the metallic silicon is metallic silicon powder with a particle size of 325 mesh.

[0018] Example 1 A material for a continuous casting functional nozzle comprises the following components in parts by weight: 40 parts corundum, 5 parts metallic silicon, 5 parts glucose, 0.5 parts urea, and 4 parts functional additives; The functional additives include the following raw materials in parts by weight: 1 part of calcium feldspar (particle size of 2μm) and 10 parts of mullite-coated aluminum titanate; The preparation method of mullite-coated aluminum titanate includes the following steps: Aluminum titanate (particle size 0.5 μm) was activated by adding aluminum titanate powder to a 10% dilute nitric acid solution at a solid-liquid ratio of 1 g: 5 mL and wet ball milling at room temperature for 2 h; filtration, washing with deionized water until the filtrate was neutral, and drying at 110 °C for 12 h to obtain pretreated aluminum titanate. Pretreated aluminum titanate was added to mullite sol (concentration of 0.20 g / L) and mixed (the mass of pretreated aluminum titanate was 25% of the mass of mullite sol), dried, and then calcined for the first time at 580℃ for 40 min. A second calcination was then performed at 1500℃ for 3 h. The mixture was then ground to obtain mullite-coated aluminum titanate. A method for preparing a material for a continuous casting functional nozzle includes the following steps: Alumina, metallic silicon, and functional additives are mixed, glucose and urea are added, granulated, dried, statically pressed, and sintered at 1100℃ for 25 hours to obtain a material for continuous casting functional nozzles.

[0019] Example 2 A material for a continuous casting functional nozzle comprises the following components in parts by weight: 50 parts corundum, 8 parts metallic silicon, 10 parts maltodextrin, 1 part urea, and 6 parts functional additives; The functional additives include the following raw materials in parts by weight: 10 parts of anorthite (particle size 4μm) and 1 part of mullite-coated aluminum titanate; The preparation method of mullite-coated aluminum titanate includes the following steps: Aluminum titanate (particle size 1 μm) was activated by adding aluminum titanate powder to a 10% dilute nitric acid solution at a solid-liquid ratio of 1 g: 5 mL and wet ball milling at room temperature for 2 h; the mixture was filtered, washed with deionized water until the filtrate was neutral, and dried at 110 °C for 12 h to obtain pretreated aluminum titanate. Pretreated aluminum titanate was added to mullite sol (concentration of 0.28 g / L) and mixed (the mass of pretreated aluminum titanate was 35% of the mass of mullite sol), dried, and then calcined for the first time at 620℃ for 25 min. A second calcination was then performed at 1550℃ for 2 h. The mixture was then ground to obtain mullite-coated aluminum titanate. A method for preparing a material for a continuous casting functional nozzle includes the following steps: Corundum, metallic silicon, and functional additives are mixed, maltodextrin and urea are added, granulated, dried, statically pressed, and sintered at 1150℃ for 20 hours to obtain a material for continuous casting functional nozzles.

[0020] Example 3 A material for a continuous casting functional nozzle comprises the following components in parts by weight: 45 parts corundum, 6 parts metallic silicon, 8 parts maltodextrin, 0.8 parts urea, and 5 parts functional additives; The functional additives include the following raw materials in parts by weight: 2 parts of anorthite (particle size 4μm) and 8 parts of mullite-coated aluminum titanate; The preparation method of mullite-coated aluminum titanate includes the following steps: Aluminum titanate (particle size 0.7 μm) was activated by adding aluminum titanate powder to a 10% dilute nitric acid solution at a solid-liquid ratio of 1 g: 5 mL and wet ball milling at room temperature for 2 h; the mixture was filtered, washed with deionized water until the filtrate was neutral, and dried at 110 °C for 12 h to obtain pretreated aluminum titanate. Pretreated aluminum titanate was added to mullite sol (concentration of 0.25 g / L) and mixed (the mass of pretreated aluminum titanate was 30% of the mass of mullite sol), dried, and then calcined for the first time at 600℃ for 32 min. A second calcination was then performed at 1530℃ for 2.5 h. The mixture was then ground to obtain mullite-coated aluminum titanate. A method for preparing a material for a continuous casting functional nozzle includes the following steps: Corundum, metallic silicon, and functional additives are mixed, maltodextrin and urea are added, granulated, dried, statically pressed, and sintered at 1120℃ for 24 hours to obtain a material for continuous casting functional nozzles.

[0021] Example 4 The difference between this embodiment and Embodiment 3 is only that the functional additives include the following raw materials in parts by weight: 8 parts of anorthite (particle size of 4μm) and 2 parts of mullite-coated aluminum titanate.

[0022] Example 5 The difference between this embodiment and Embodiment 3 is only that the functional additives include the following raw materials in parts by weight: 1 part of calcium feldspar (particle size of 4μm) and 9 parts of mullite-coated aluminum titanate.

[0023] Example 6 The difference between this embodiment and Embodiment 3 is only that the functional additives include the following raw materials in parts by weight: 9 parts of anorthite (particle size of 4μm) and 1 part of mullite-coated aluminum titanate.

[0024] Comparative Example 1 The only difference between this comparative example and Example 3 is that the functional additive is anorthite (particle size 4 μm).

[0025] Comparative Example 2 The only difference between this comparative example and Example 3 is that the functional additive is mullite-coated aluminum titanate.

[0026] Comparative Example 3 The only difference between this comparative example and Example 3 is that the functional additives include the following raw materials in parts by weight: 2 parts of anorthite (particle size 4 μm) and 8 parts of aluminum titanate (particle size 0.7 μm).

[0027] Experimental Example 1 The thermal shock resistance and flexural strength of the continuous casting functional nozzle materials prepared in Examples 1-6 and Comparative Examples 1-3 were tested respectively. Flexural strength: according to GB / T 3002-2017 "Test Method for High Temperature Flexural Strength of Refractory Materials", the test temperature was 1400℃ and the time was 3h. The results are shown in Table 1 below.

[0028] Table 1. Test results of material properties for continuous casting functional nozzles prepared in Examples 1-6 and Comparative Examples 1-3

[0029] Compared with Comparative Examples 1-3, the thermal shock resistance and flexural strength of the continuous casting functional nozzle materials prepared in Examples 1-6 are superior, indicating that the use of calcium feldspar and mullite to coat aluminum titanate as functional additives improves the thermal shock resistance and strength of the continuous casting functional nozzle materials.

[0030] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A material for a functional nozzle in continuous casting, characterized in that, Includes the following components in parts by weight: 40-50 parts corundum, 5-8 parts metallic silicon, 5-10 parts glucose or maltodextrin, 0.5-1 part urea, and 4-6 parts functional additives; The functional additives include the following raw materials in parts by weight: 1-10 parts of calcium feldspar and 1-10 parts of mullite-coated aluminum titanate.

2. The material for a continuous casting functional nozzle according to claim 1, characterized in that, The mass ratio of the calcium feldspar and mullite-coated aluminum titanate is 1:4 to 4:

1.

3. The material for a continuous casting functional nozzle according to claim 1, characterized in that, The preparation method of the mullite-coated aluminum titanate includes the following steps: Aluminum titanate is activated to obtain pretreated aluminum titanate; The pretreated aluminum titanate was added to mullite sol, mixed, dried, calcined, and ground to obtain mullite-coated aluminum titanate.

4. The material for a continuous casting functional nozzle according to claim 3, characterized in that, The mass of the pretreated aluminum titanate is 25% to 35% of the mass of the mullite sol.

5. The material for a continuous casting functional nozzle according to claim 3, characterized in that, The calcination includes a first calcination and a second calcination.

6. The material for a continuous casting functional nozzle according to claim 3, characterized in that, The temperature of the first calcination is 580~620℃, and the time is 25~40min; The second calcination is carried out at a temperature of 1500~1550℃ for 2~3 hours.

7. The material for a continuous casting functional nozzle according to claim 3, characterized in that, The anorthite has a particle size of 2-4 μm; the aluminum titanate has a particle size of 0.5-1 μm.

8. The material for a continuous casting functional nozzle according to claim 3, characterized in that, The concentration of the mullite sol is 0.20~0.28 g / L.

9. A method for preparing a material for a continuous casting functional nozzle, used to prepare the material for a continuous casting functional nozzle as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Alumina, metallic silicon, and functional additives are mixed, and glucose or maltodextrin and urea are added. The mixture is then granulated, dried, shaped, and sintered to obtain a material for continuous casting functional nozzles.

10. A method for preparing a material for a continuous casting functional nozzle according to claim 9, characterized in that, The sintering temperature is 1100~1150℃ and the time is 20~25h.

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