Anti-nodulation submersed nozzle lining material and preparation method thereof

Abstract

The invention discloses an anti-nodulation submersed nozzle lining material and a preparation method thereof, and belongs to the technical field of refractory materials, the submersed nozzle lining material comprises, by mass, 40-60% of electrosmelted chromic oxide aggregate, 15-24% of quartz, 16-28% of pre-synthesized CrSiC composite powder and 8-15% of thermosetting phenolic resin, wherein the pre-synthesized CrSiC composite powder comprises 30-40% of chromium oxide fine powder, 25-35% of silicon oxide fine powder and 25-35% of a carbon raw material. The submerged nozzle lining has the characteristic of resisting aluminum oxide inclusion adsorption, solves the problem that the submerged nozzle lining is easy to nodulate, has good thermal shock resistance, and ensures field use and safety.

Description

Technical Field

[0001] This invention relates to a type of anti-nodulation submersible nozzle lining material and its preparation method, belonging to the field of refractory materials technology. Background Technology

[0002] Submerged entry nozzles, serving as the main molten steel channel connecting the tundish and the crystallizer, are key functional refractory materials affecting the smooth operation of continuous casting and the quality of the cast billet. Due to the drastic temperature rise of the nozzle during the casting process, the nozzle body is typically made of alumina-carbon materials with alumina and graphite as the main raw materials. The nozzle lining, which withstands both intense scouring and thermal shock from the molten steel, is usually made of hollow alumina spheres, offering good resistance to scouring and thermal shock. However, in the continuous casting of low-carbon alumina-killed steel, low-carbon alumina-silicon-killed steel, and other low-alloy steels, inclusions such as alumina, calcium aluminate, and spinel in the molten steel easily undergo physical and chemical adsorption with the alumina lining, leading to deposition on the inner wall of the nozzle. This can easily cause nozzle blockage, resulting in crystallizer surface fluctuations, severe slag crusting, and in severe cases, even interruption of continuous casting production.

[0003] Although measures such as inclusion modification treatment, improved nozzle structure, and the use of carbon-free nozzle linings can reduce nozzle clogging to some extent, the effect is still not ideal and cannot meet the continuous casting requirements of high-quality steel. In the prior art, a preferred method for an anti-nodulation lining material for submerged entry nozzles (CN202311630735.8) shows through theoretical calculations that zirconia is less conducive to the nucleation and growth of alumina inclusions in molten steel than alumina or magnesium aluminum spinel lining materials, thus exhibiting better anti-nodulation performance. However, zirconia materials have poor thermal shock stability, making them prone to cracking or even explosion during the initial casting process, affecting on-site use and safety. A submerged entry nozzle lining material for rare earth steel continuous casting and its preparation method (CN202510699213.6) lowers the sintering temperature and increases density by adding silicon nitride iron powder, boron carbide powder, and metallic silicon powder, reducing the lining porosity and thus reducing inclusion adsorption sites. However, this method significantly reduces the material's thermal shock stability. In summary, existing technologies cannot simultaneously solve the problems of easy nodule formation and poor thermal shock resistance in submerged nozzle linings. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide an anti-nodulation immersion nozzle liner material and its preparation method, which has the adsorption characteristics of alumina inclusions, solves the problem of nodulation in immersion nozzle liners, and at the same time has good thermal shock resistance, ensuring field use and safety.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention discloses an anti-nodulation immersion nozzle lining material, which, by weight, comprises 40-60% fused chromium oxide aggregate, 15-24% quartz, 16-28% pre-synthesized CrSiC composite powder, and 8-15% thermosetting phenolic resin, wherein the pre-synthesized CrSiC composite powder comprises 30-40% chromium oxide fine powder, 25-35% silicon oxide fine powder, and 25-35% carbon raw material.

[0007] The fine chromium oxide powder has a particle size of 325-200 mesh, and the Cr2O3 content is greater than 98%.

[0008] The silica powder has a particle size of 325-200 mesh, and the SiO2 content is greater than 98%.

[0009] The carbon raw materials include one or a combination of flake graphite and nano carbon black.

[0010] The flake graphite has a particle size of 325-200 mesh, and the content of fixed carbon is greater than 99%.

[0011] The nano-carbon black has a particle size of 0.05~0.2µm, and the content of fixed carbon is greater than 99%.

[0012] Secondly, this invention discloses a method for preparing an anti-nodulation immersion nozzle liner material, comprising the following steps:

[0013] Weigh out fused chromium oxide aggregate, quartz, pre-synthesized CrSiC composite powder and thermosetting phenolic resin according to the formula, mix them evenly and then process them into mud through kneading and drying.

[0014] The clay is then subjected to a process of acclimation and homogenization, followed by isostatic pressing.

[0015] Finally, it is sintered and then machined to the required size.

[0016] The isostatic pressing pressure is 40~80 MPa; the sintering temperature is 1400~1600℃; and the sintering time is 4~8 hours.

[0017] The preparation method of the pre-synthesized CrSiC composite powder includes:

[0018] Weigh out the fine chromium oxide, fine silicon oxide, and carbon raw materials according to the specified ratio;

[0019] After mixing, the mixture is kept warm in an argon or carbon-buried atmosphere.

[0020] Finally, grinding and sieving are performed to obtain the final product.

[0021] The insulation treatment temperature is 1200~1400℃, and the insulation time is 3~6 hours.

[0022] The beneficial effects of this invention are as follows: This invention provides an anti-nodulation submerged nozzle lining material and its preparation method. The submerged nozzle lining material is prepared using chromium oxide aggregate, quartz, and pre-synthesized CrSiC composite powder as main raw materials. Chromium oxide has low solubility in molten steel and high thermal conductivity, resulting in strong thermal shock resistance and erosion resistance. Quartz has a low coefficient of thermal expansion and strong thermal shock resistance. The CrSiC composite powder has high compatibility with chromium oxide and quartz. Furthermore, the pre-synthesized CrSiC composite powder is a layered compound with good thermal conductivity and resistance to slag and melt erosion, significantly improving the thermal shock resistance and erosion resistance of the lining material. During high-temperature service, the Si in CrSiC selectively oxidizes to form a dense SiO2 layer on the surface, sealing pores and reducing Al2O3 inclusion adsorption sites in the molten steel. The residual CrC retains its microporous layered structure, further improving the material's thermal shock performance. This results in a final lining material with high thermal shock resistance, erosion resistance, and anti-nodulation capabilities.

[0023] CrSiC compounds are expensive. This invention uses common refractory raw materials such as chromium oxide, silicon oxide, and carbon raw materials to form a composite powder with CrSiC as the main component by high-temperature carbothermic reduction. The synthesis cost is low and the process is simple. Detailed Implementation

[0024] The present invention will be further described below. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0025] Example 1

[0026] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: 30% chromium oxide fine powder, 35% silicon oxide fine powder and 35% flake graphite are used as raw materials by mass. After mixing, the mixture is heated at 1200℃ for 3 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained. The CrSiC content in the composite powder is about 75%.

[0027] By weight, 60% fused chromium oxide aggregate, 16% quartz, 16% pre-synthesized CrSiC composite powder, and 8% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 40 MPa. After sintering at 1600℃ for 8 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0028] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0029] The particle size of flake graphite is 325~200 mesh, and the content of fixed carbon is greater than 99%.

[0030] Example 2

[0031] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: by mass, 40% chromium oxide fine powder, 35% silicon oxide fine powder and 25% flake graphite are used as raw materials. After mixing, the mixture is subjected to heat treatment at 1400℃ for 6 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained, with a CrSiC content of about 79% in the composite powder.

[0032] By weight, 60% fused chromium oxide aggregate, 16% quartz, 16% pre-synthesized CrSiC composite powder, and 8% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 40 MPa. After sintering at 1600℃ for 8 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0033] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0034] The particle size of flake graphite is 325~200 mesh, and the content of fixed carbon is greater than 99%.

[0035] Example 3

[0036] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: by mass, 38% chromium oxide fine powder, 32% silicon oxide fine powder, 20% flake graphite and 10% nano carbon black are used as raw materials. After mixing, the mixture is subjected to heat treatment at 1200℃ for 4 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained, with a CrSiC content of about 90% in the composite powder.

[0037] By weight, 50% fused chromium oxide aggregate, 14% quartz, 21% pre-synthesized CrSiC composite powder, and 15% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 60 MPa. After sintering at 1400℃ for 6 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0038] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0039] The particle size of flake graphite is 325~200 mesh, with a fixed carbon content greater than 99%. The particle size of nano carbon black is 0.05~0.2µm, with a fixed carbon content greater than 99%.

[0040] Example 4

[0041] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: by mass, 40% chromium oxide fine powder, 25% silicon oxide fine powder, 20% flake graphite and 15% nano carbon black are used as raw materials. After mixing, the mixture is subjected to heat treatment at 1300℃ for 4 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained, with a CrSiC content of about 85% in the composite powder.

[0042] By weight, 50% fused chromium oxide aggregate, 14% quartz, 21% pre-synthesized CrSiC composite powder, and 15% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 60 MPa. After sintering at 1400℃ for 6 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0043] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0044] The particle size of flake graphite is 325~200 mesh, with a fixed carbon content greater than 99%. The particle size of nano carbon black is 0.05~0.2µm, with a fixed carbon content greater than 99%.

[0045] Example 5

[0046] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: by mass, 40% chromium oxide fine powder, 35% silicon oxide fine powder, 17% flake graphite and 8% nano carbon black are used as raw materials. After mixing, the mixture is subjected to heat treatment at 1300℃ for 5 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained, with a CrSiC content of about 62% in the composite powder.

[0047] By weight, 40% fused chromium oxide aggregate, 24% quartz, 28% pre-synthesized CrSiC composite powder, and 8% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 80 MPa. After sintering at 1400℃ for 4 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0048] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0049] The particle size of flake graphite is 325~200 mesh, with a fixed carbon content greater than 99%. The particle size of nano carbon black is 0.05~0.2µm, with a fixed carbon content greater than 99%.

[0050] Example 6

[0051] This invention discloses a method for preparing an anti-nodulation immersion nozzle liner material. The specific preparation process is as follows: by mass, 38% chromium oxide fine powder, 34% silicon oxide fine powder, 18% flake graphite and 10% nano carbon black are used as raw materials. After mixing, the mixture is subjected to heat treatment at 1300℃ for 5 hours under an argon atmosphere. After grinding and sieving, a pre-synthesized CrSiC composite powder is obtained, with a CrSiC content of approximately 64% in the composite powder.

[0052] By weight, 40% fused chromium oxide aggregate, 24% quartz, 28% pre-synthesized CrSiC composite powder, and 8% thermosetting phenolic resin are mixed evenly according to the specified ratio, and then the mixture is kneaded and dried to form a mud. The mud is then subjected to bridging and homogenization, and then isostatically pressed under a pressure of 80 MPa. After sintering at 1400℃ for 4 hours, it is processed to the required size to obtain the anti-nodulation lining material.

[0053] The chromium oxide fine powder has a particle size of 325-200 mesh, with a Cr2O3 content greater than 98%. The silicon oxide fine powder has a particle size of 325-200 mesh, with a SiO2 content greater than 98%.

[0054] The particle size of flake graphite is 325~200 mesh, with a fixed carbon content greater than 99%. The particle size of nano carbon black is 0.05~0.2µm, with a fixed carbon content greater than 99%.

[0055] Comparative Example

[0056] It adopts a common aluminum carbon body, with an inner diameter of 50mm for the sprue. The sprue lining is made of hollow alumina spheres with an Al2O3 content of 50-60%, SiO2 content of 15-25%, and carbon content of 15-25%.

[0057] Table 1. Thickness of the nodule layer on the inner wall of the sluice gate corresponding to various embodiments of the present invention.

[0058]

[0059] This invention selected Al-deoxidized ultra-low carbon steel ([Al]: 0.05%) as the casting material for testing. 290t of steel / ladle, casting speed 1.1-1.4m / min, 12 heats, 50min / heat. The experiment was conducted on a continuous casting machine with an eight-strand casting configuration. One strand was selected as the experimental strand, and the symmetrical strand as the control strand. After casting of the control strand, the submerged entry nozzle was removed, and the thickness of the nodule was measured. After continuous casting tests, the thickness of the nodule layer on the inner wall of the control strand was approximately 15.2mm. The thickness of the nodule layer on the inner wall of the nozzle corresponding to each embodiment of this invention is shown in Table 1, ranging from 3.1mm to 4.9mm. The data comparison shows that the submerged entry nozzle lining material prepared by this invention can effectively prevent nodule formation and significantly reduce the thickness of the nodule layer. Furthermore, the submerged entry nozzle lining material corresponding to Example 3 showed the best effect because the pre-synthesized CrSiC composite powder prepared in this example had the highest CrSiC content.

[0060] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A type of anti-nodulation immersion nozzle liner material, characterized in that: By weight, it includes 40-60% fused chromium oxide aggregate, 15-24% quartz, 16-28% pre-synthesized CrSiC composite powder and 8-15% thermosetting phenolic resin, wherein the pre-synthesized CrSiC composite powder includes 30-40% chromium oxide fine powder, 25-35% silicon oxide fine powder and 25-35% carbon raw materials.

2. The anti-nodulation immersion nozzle liner material according to claim 1, characterized in that: The fine chromium oxide powder has a particle size of 325-200 mesh, and the Cr2O3 content is greater than 98%.

3. The anti-nodulation submersible nozzle liner material according to claim 1, characterized in that: The silica powder has a particle size of 325-200 mesh, and the SiO2 content is greater than 98%.

4. The anti-nodulation submersible nozzle liner material according to claim 1, characterized in that: The carbon raw materials include one or a combination of flake graphite and nano carbon black.

5. The anti-nodulation submersible nozzle liner material according to claim 4, characterized in that: The flake graphite has a particle size of 325-200 mesh, and the content of fixed carbon is greater than 99%.

6. The anti-nodulation submersible nozzle liner material according to claim 4, characterized in that: The nano-carbon black has a particle size of 0.05~0.2µm, and the content of fixed carbon is greater than 99%.

7. A method for preparing an anti-nodulation submersible nozzle liner material according to any one of claims 1 to 6, characterized in that: Includes the following steps: Weigh out fused chromium oxide aggregate, quartz, pre-synthesized CrSiC composite powder and thermosetting phenolic resin according to the formula, mix them evenly and then process them into mud through kneading and drying. The clay is then subjected to a process of acclimation and homogenization, followed by isostatic pressing. Finally, it is sintered and then machined to the required size.

8. The method for preparing the anti-nodulation submersible nozzle liner material according to claim 7, characterized in that: The isostatic pressing pressure is 40~80 MPa; the sintering temperature is 1400~1600℃; and the sintering time is 4~8 hours.

9. The method for preparing the anti-nodulation submersible nozzle liner material according to claim 7, characterized in that: The preparation method of the pre-synthesized CrSiC composite powder includes: Weigh out the fine chromium oxide, fine silicon oxide, and carbon raw materials according to the specified ratio; After mixing, the mixture is kept warm in an argon or carbon-buried atmosphere. Finally, grinding and sieving are performed to obtain the final product.

10. The method for preparing the anti-nodulation immersion nozzle liner material according to claim 9, characterized in that: The insulation treatment temperature is 1200~1400℃, and the insulation time is 3~6 hours.

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