Continuous casting functional refractory material stirred by inert gas and used for high-quality variety steel and preparation method of refractory material

Abstract

The invention discloses a continuous casting functional refractory material stirred by inert gas and used for high-quality variety steel. The invention discloses a high-strength graphite-based composite material which comprises the following components: 28%-32% of graphite, 28%-32% of white corundum, 10%-14% of alumina powder, 6%-10% of quartz, 3%-7% of metal silicon powder, 1%-3% of aluminum fiber, 3%-4% of a ceramic adhesive, 4%-6% of sodium bentonite, 1%-3% of a reinforcing agent, 2%-4% of boron carbide and 10%-14% of phenolic resin. The invention provides a continuous casting functional refractory material stirred by inert gas for high-quality variety steel and a preparation method thereof, which have the advantages of long service life, local process, reduction of molten steel inclusion, guarantee of thermal shock resistance and molten steel erosion resistance.

Description

Technical Field

[0001] The present invention relates to the field of inorganic non-metallic refractory materials, and more specifically to a high-quality steel continuous casting functional refractory material stirred by inert gas and a preparation method thereof. Background Art

[0002] After the 20th century, with the technological progress of countries around the world, the requirements for steel performance have become increasingly stringent, and various studies have shown that when the impurities in steel are reduced to a certain level, the performance of the steel will have a qualitative leap. Therefore, more and more types of steel have emerged, and the continuous casting process requirements of these steels are becoming more and more stringent, requiring continuous casting refractory materials to not only meet the service life, but also have certain special functions.

[0003] With the market demand for the smelting of high-performance and high-quality steel varieties such as silicon steel and automotive plates, the continuous pouring time of the tundish is getting longer and longer. The continuous casting functional refractory cannot be damaged or replaced during the process to prevent nitrogen increase in the molten steel and inclusion of foreign matter.

[0004] As more and more steel mills have demands for special steel smelting, high-quality, special-function continuous casting refractory materials have emerged. For this reason, the market currently lacks a method to achieve localization and domestic production of such high-end refractory materials. After repeated certification, it was decided to research and develop the project of inert gas agitated continuous casting functional refractory materials used in Baosteel's high-performance and high-quality steel varieties, in order to ensure thermal shock stability and resistance to molten steel erosion, reduce molten steel inclusions, and meet the requirements of high-performance and high-quality varieties of refractory materials. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a continuous casting functional refractory material stirred by inert gas for high-quality steel with long service life, localized process, reduced molten steel inclusions, guaranteed thermal shock stability and resistance to molten steel erosion, and a preparation method thereof.

[0006] According to one aspect of the present invention, there is provided a continuous casting functional refractory material for high-quality steel with inert gas stirring, which comprises the following components in weight percentage: 28%-32% graphite, 28%-32% white corundum, 10%-14% alumina powder, 6%-10% quartz, 3%-7% metallic silicon powder, 1%-3% aluminum fiber, 3%-4% ceramic plastic binder, 4%-6% sodium bentonite, 1%-3% reinforcing agent and 2%-4% boron carbide, plus 10%-14% phenolic resin.

[0007] In some embodiments, the graphite specifications are: particle size 50 mesh, content ≥95.0%, moisture ≤0.5%, particle size 80 mesh, content ≥95.0%, moisture ≤0.5%;

[0008] The specifications of white corundum are: particle size 36#-70#, particle size 80# and particle size 200#;

[0009] Alumina powder particle size: 10-50μm;

[0010] Quartz specifications: particle size 70#-150#;

[0011] The specifications of metal silicon powder are: particle size 200#;

[0012] Aluminum fiber specifications are: diameter 0.1mm-0.3mm, length 2mm-4mm;

[0013] Specifications of sodium bentonite are: particle size 200 mesh;

[0014] The specification of boron carbide is: particle size 325#.

[0015] In some embodiments, the weight percentage of graphite particle size 50 mesh is 15%;

[0016] The weight percentage of graphite particle size 80 mesh is 15%.

[0017] In some embodiments, the weight percentage of white corundum particle size 36#-70# is 8%;

[0018] The weight percentage of white corundum particle size 80# is 12%;

[0019] The weight percentage of white corundum particle size 200# is 10%.

[0020] In some embodiments, the enhancer is aluminum sulfate.

[0021] According to one aspect of the present invention, a method for preparing a high-quality steel continuous casting functional refractory stirred by inert gas is provided, comprising the following steps:

[0022] S1. Raw material selection;

[0023] S2, ingredients, add each group of ingredients according to the proportion;

[0024] S3, mixing and granulating, using a granulator to mix and granulate;

[0025] S4, screening, using a vibrating screen to screen the granulation raw materials;

[0026] S5, trapping the material, sealing 75% of the raw materials;

[0027] S6, mixing, using a horizontal mixing device to mix the finished raw materials and the remaining 25% of the raw materials evenly;

[0028] S7, inspecting and determining the particle size, moisture content and green body density of the mixed raw materials;

[0029] S8, forming, using die-casting equipment to press the mixed principle into a stopper rod blank;

[0030] S9, drying, drying the formed green body;

[0031] S10, firing, pushing the stopper rod blank into a high-temperature tunnel kiln for firing, and then cooling to room temperature before taking it out of the kiln;

[0032] S11, processing, processing the outer circle and slag line thickness of the stopper rod;

[0033] S12, spraying, spraying glaze on the outside of the stopper rod using an automatic glaze dipping device;

[0034] S13. Inspection: Check the appearance, size and physical and chemical indicators of the finished product;

[0035] S14. Qualified products are packaged and put into storage, and unqualified products are destroyed.

[0036] In some embodiments, in S3, the raw materials need to be premixed and preheated before kneading. The premixing is performed by mixing the raw materials with a stirring device and preheating the premixed raw materials at a temperature of 70°C-80°C.

[0037] In some embodiments, in S5, 75% of the raw materials are placed in a silo or a material storage area and covered with plastic sheeting to ensure that the raw materials do not come into contact with water. The air temperature should be greater than 15°C and the raw materials are left to stand for more than 24 hours. At the same time, constant temperature and humidity are required, and the mud is placed in multiple layers to achieve a reasonable combination of the mud materials and ensure the stability of the mud material indicators.

[0038] In some embodiments, the drying in step S9 includes natural drying and heat drying, wherein the natural drying is drying at room temperature above 15°C for more than 6 hours, and the heat drying is drying in a heating kiln at 110°C-150°C for 1-2 hours.

[0039] In some embodiments, firing comprises the following steps:

[0040] S1, loading, pushing the stopper rod blank into the high temperature tunnel kiln;

[0041] S2, heating, uniformly heating to 550℃-750℃ within 5 hours;

[0042] S3, high temperature firing, the high temperature tunnel kiln is heated to 1550-1650℃ for firing within 4 hours;

[0043] S4, heat preservation, heat preservation and firing at 1550-1650℃ for 18 hours to 24 hours;

[0044] S5, cooling, uniformly cooling to 150℃-200℃ within 8 hours;

[0045] S6. Cooling: Cooling to room temperature and taking the fired stopper rod out of the kiln.

[0046] The present invention discloses a continuous casting functional refractory material stirred by inert gas for high-quality steel, which has the beneficial effects of long service life, localized process, reduced inclusions in molten steel, guaranteed thermal shock stability and resistance to erosion by molten steel. Through the use of technical processes, the steel plant cooperates with the optimization of baking conditions, and prepares sample blocks by selecting the best raw materials, particle size, and different adjustments of binders, and measures its chemical composition, residual carbon rate, volume density, apparent porosity, room temperature compressive strength, room temperature flexural strength, and high temperature flexural strength. After data analysis, the best formula is selected to ensure the thermal shock stability and resistance to erosion by molten steel of the refractory material; through the composite of the inner cavity breathable material of the cast functional refractory material and the bowl mouth directional blowing inert gas material, small bubbles of argon are blown, and the bowl mouth and the stopper rod head are purged to prevent the alumina adsorbent from agglomerating at the bowl mouth of the water inlet and the head of the stopper rod, reduce the inclusion of foreign matter in molten steel, and reduce the fluctuation of the molten steel liquid level, thereby improving the quality of clean steel; the inner cavity of the continuous casting functional refractory material diffuses and blows inert gas, and the pinholes in the bowl mouth directional blowing of inert gas work simultaneously. DETAILED DESCRIPTION

[0047] The present invention is described in detail below in conjunction with various embodiments, but it should be noted that these embodiments are not limitations of the present invention, and equivalent changes or substitutions in functions, methods or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the terms can be understood according to the specific circumstances.

[0049] The invention discloses a high-quality steel continuous casting functional refractory material stirred by inert gas. The invention comprises the following components by weight percentage: 28%-32% graphite, 28%-32% white corundum, 10%-14% alumina powder, 6%-10% quartz, 3%-7% metallic silicon powder, 1%-3% aluminum fiber, 3%-4% ceramic plastic adhesive, 4%-6% sodium bentonite, 1%-3% reinforcing agent and 2%-4% boron carbide, and 10%-14% phenolic resin.

[0050] Graphite is an allotrope of carbon. It is a gray-black, opaque solid with stable chemical properties, corrosion resistance, and is not easy to react with acids, alkalis and other agents. The melting point of graphite is 3850±50℃. Even if it is burned by ultra-high temperature arc, the weight loss is very small and the thermal expansion coefficient is also very small. The strength of graphite increases with the increase of temperature. At 2000℃, the strength of graphite doubles. When used at room temperature, graphite can withstand drastic changes in temperature without being damaged. When the temperature changes suddenly, the volume of graphite does not change much and no cracks will occur.

[0051] The graphite specifications are: particle size 50 mesh, content ≥95.0%, moisture ≤0.5%, particle size 80 mesh, content ≥95.0%, moisture ≤0.5%.

[0052] The weight percentage of graphite particle size 50 mesh is 15%;

[0053] The weight percentage of graphite particle size 80 mesh is 15%.

[0054] White corundum is a white material with a content of more than 99% aluminum oxide (Al2O3) and a small amount of iron oxide, silicon oxide and other ingredients. It has a dense texture, high hardness, and sharp corners. It is suitable for the manufacture of ceramics, resin-bonded abrasives, grinding, polishing, sandblasting, precision casting (special corundum for precision casting), etc. It can also be used to manufacture advanced refractory materials.

[0055] The specifications of white corundum are: particle size 36#-70#, particle size 80# and particle size 200#.

[0056] The weight percentage of white corundum particle size 36#-70# is 8%;

[0057] The weight percentage of white corundum particle size 80# is 12%;

[0058] The weight percentage of white corundum particle size 200# is 10%.

[0059] The particle size of alumina powder is 10-50μm. Alumina (aluminum oxide) is an inorganic substance with the chemical formula Al2O3. It is a high hardness compound with a melting point of 2054℃ and a boiling point of 2980℃. It is an ion crystal that can be ionized at high temperatures.

[0060] The specifications of quartz are: particle size 70#-150#; the main component is SiO2, colorless and transparent, often containing a small amount of impurities, and becoming translucent or opaque crystals, with a hard texture. Grease luster, density is 2.65g / cm 3 Its chemical, thermal and mechanical properties have obvious anisotropy. It is insoluble in acid, slightly soluble in KOH solution, and has a melting point of 1750℃.

[0061] The specifications of metal silicon powder are: particle size 200#; metal silicon powder is a multifunctional industrial raw material, widely used in many fields. Its main uses include refractory materials, powder metallurgy, organic silicon polymer synthesis and metallurgical casting. In these fields, metal silicon powder is mainly used to improve the high temperature resistance, wear resistance and oxidation resistance of products, and can also be used as a deoxidizer and alloy additive.

[0062] The specifications of aluminum fiber are: diameter 0.1mm-0.3mm, length 2mm-4mm; aluminum fiber can significantly improve the strength and wear resistance of tiles, reduce the risk of breakage and deformation, and has the characteristics of high strength and high modulus, which is suitable for enhancing the mechanical properties of materials. Aluminum fiber can still maintain stable performance at high temperatures and is suitable for applications in high temperature environments.

[0063] Ceramic plastic adhesive can increase the toughness and strength of refractory materials, fill the tiny cracks or fractures in refractory products, thereby improving their impact resistance and ability to withstand external forces.

[0064] The specifications of sodium bentonite are: particle size 200 mesh; good thermal stability, high plasticity and strong adhesion, high hot wet tensile strength and dry compressive strength.

[0065] Boron carbide specifications: particle size 325#. Used for wear resistance and corrosion resistance of refractory materials.

[0066] The reinforcing agent is aluminum sulfate. As a filler, it is filled in the refractory material. Adding aluminum sulfate can increase the density and hardness of the material, improve the thermal stability and refractory performance of the material, and also improve the mechanical and chemical properties of the material; a reinforcing agent that increases the stability and refractory performance of the refractory material. Aluminum sulfate can form a stable physical and chemical structure in the material, increase the density and hardness of the material, and improve its fire resistance and corrosion resistance.

[0067] Phenolic resin, as a binder, has a multifunctional property that makes it compatible with a variety of organic and inorganic fillers. In particular, it has a fast wetting speed and can provide the required mechanical strength, heat resistance and electrical properties for abrasives, refractory materials, friction materials and bakelite powder after cross-linking.

[0068] After testing, the following table shows the optimal ratio.

[0069]

[0070] The present invention provides a method for preparing a high-quality steel continuous casting functional refractory material stirred by inert gas, comprising the following steps:

[0071] S1. Raw material selection;

[0072] S2, ingredients, add each group of ingredients according to the proportion;

[0073] S3, mixing and granulating, using a granulator to mix and granulate;

[0074] S4, screening, using a vibrating screen to screen the granulation raw materials;

[0075] S5, trapping the material, sealing 75% of the raw materials;

[0076] S6, mixing, using a horizontal mixing device to mix the finished raw materials and the remaining 25% of the raw materials evenly;

[0077] S7, inspecting and determining the particle size, moisture content and green body density of the mixed raw materials;

[0078] S8, forming, using die-casting equipment to press the mixed principle into a stopper rod blank;

[0079] S9, drying, drying the formed green body;

[0080] S10, firing, pushing the stopper rod blank into a high-temperature tunnel kiln for firing, and then cooling to room temperature before taking it out of the kiln;

[0081] S11, processing, processing the outer circle and slag line thickness of the stopper rod;

[0082] S12, spraying, spraying glaze on the outside of the stopper rod using an automatic glaze dipping device;

[0083] S13. Inspection: Check the appearance, size and physical and chemical indicators of the finished product;

[0084] S14. Qualified products are packaged and put into storage, and unqualified products are destroyed.

[0085] Requirements for the physical and chemical performance indicators of finished products made from refractory raw materials:

[0086] project index <![CDATA[Al2O3%]]> ≥42 C％ ≥23 <![CDATA[Bulk density g / cm 3 > ≥2.2 Apparent gas rate% ≤19 Normal temperature compressive strength MPa ≥19 Thermal shock resistance 1100℃, water cooling ≥5

[0087] In S3, the raw materials need to be premixed and preheated before kneading. The premixing is performed by mixing the raw materials with a stirring device and preheating the premixed raw materials at a temperature of 70° C. to 80° C.

[0088] In S5, 75% of the raw materials are placed in a silo or material storage area and covered with plastic sheeting to ensure that the raw materials do not come into contact with water. The air temperature should be greater than 15°C and left to stand for more than 24 hours. At the same time, constant temperature and humidity are required, and the clay is placed in multiple layers to achieve a reasonable combination of clay materials and ensure the stability of clay material indicators.

[0089] The drying in step S9 includes natural drying and heating drying. The natural drying is drying at room temperature above 15° C. for more than 6 hours, and the heating drying is drying in a heating kiln at 110° C.-150° C. for 1-2 hours.

[0090] Firing includes the following steps:

[0091] S1, loading, pushing the stopper rod blank into the high temperature tunnel kiln;

[0092] S2, heating, uniformly heating to 550℃-750℃ within 5 hours;

[0093] S3, high temperature firing, the high temperature tunnel kiln is heated to 1550-1650℃ for firing within 4 hours;

[0094] S4, heat preservation, heat preservation and firing at 1550-1650℃ for 18 hours to 24 hours;

[0095] S5, cooling, uniformly cooling to 150℃-200℃ within 8 hours;

[0096] S6. Cooling: Cooling to room temperature and taking the fired stopper rod out of the kiln.

[0097] Continuous casting of high-quality steel is a modern process in the metallurgical industry. Its advantages are fewer processes, shorter processes, lower material and energy consumption, fewer personnel, and significantly reduced production costs, greatly improved steel quality and optimized product structure. At present, my country's continuous casting ratio must reach 100%. High-end continuous casting functional refractory materials are localized. According to the requirements of new industrialization and the development of longer-lasting, more energy-saving, pollution-free (green) functional new refractory materials, the domestic market demand for this invention product is huge, with an annual demand of more than 12,000 tons.

[0098] The product developed by the present invention is a high-quality steel continuous casting functional refractory material stirred by inert gas, which meets the needs of steel mills with advanced world standards.

[0099] According to the consumption of continuous casting steel, the demand is relatively large, and the demand for high-quality steel with inert gas agitation continuous casting functional refractory materials by large and medium-sized steel enterprises across the country will increase significantly. The annual growth rate is estimated to be above 15%, and the economic life of the product is 15 years. The product of the present invention is currently in the development stage and has a strong competitive advantage in the domestic and foreign markets.

[0100] Comparing the price and quality, the product of the present invention is about 35% lower than the imported price, and the service life is increased by 30%, reaching more than 15 furnaces, and the highest is 20 furnaces. It is at the international advanced level, fills the domestic gap, and can replace exports.

[0101] Actual measured indicators of the main body (inner cavity) of the continuous casting functional refractory material stirred by inert gas for high-quality steel:

[0102] project unit Measured value <![CDATA[AL2O3]]> ％ 52.5 F.C. ％ 25.2 Bulk density <![CDATA[g / cm 3 ]]> 2.40-2.5 Apparent porosity ％ 16.5-18.0 Normal temperature compressive strength MPa 22.5-30.0 Flexural strength at room temperature MPa 6.5-9.5

[0103] From the usage data, the maximum number of furnaces used is 20. Flow rate: 3L / min-7L / min, back pressure is stable at 90Kpa-150Kpa, and the stopper opening is stable, indicating that there are few nodules on the mouth of the nozzle and the head of the stopper, and it has good castability. On-site users also reported that the high-quality steel inert gas agitated continuous casting functional refractory produced by our company has no significant difference in product use results compared with the normal manufacturer, and can replace imported products.

[0104] The above are only some embodiments of the present invention. It should be pointed out that for ordinary technicians in this field, other modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. High-quality steel continuous casting functional refractory stirred by inert gas, characterized in that: Calculated by weight percentage, the invention comprises the following components: 28%-32% graphite, 28%-32% white corundum, 10%-14% alumina powder, 6%-10% quartz, 3%-7% metallic silicon powder, 1%-3% aluminum fiber, 3%-4% ceramic plastic adhesive, 4%-6% sodium bentonite, 1%-3% reinforcing agent and 2%-4% boron carbide, and 10%-14% phenolic resin.

2. The high-quality steel continuous casting functional refractory material stirred by inert gas according to claim 1 is characterized in that: The graphite specifications are: particle size 50 mesh, content ≥95.0%, moisture ≤0.5%, particle size 80 mesh, content ≥95.0%, moisture ≤0.5%; The specifications of the white corundum are: particle size 36#-70#, particle size 80# and particle size 200#; The particle size of the alumina powder is: 10-50 μm; The quartz specifications are: particle size 70#-150#; The specifications of the metal silicon powder are: particle size 200#; The aluminum fiber specifications are: diameter 0.1mm-0.3mm, length 2mm-4mm; The sodium bentonite specifications are: particle size 200 mesh; The specification of the boron carbide is: particle size 325#.

3. The high-quality steel continuous casting functional refractory stirred by inert gas according to claim 2, characterized in that: The weight percentage of the graphite particle size 50 mesh is 15%; The weight percentage of the graphite particle size 80 mesh is 15%.

4. The high-quality steel continuous casting functional refractory material stirred by inert gas according to claim 3 is characterized in that: The weight percentage of the white corundum particle size 36#-70# is 8%; The weight percentage of the white corundum particle size 80# is 12%; The weight percentage of the white corundum with a particle size of 200# is 10%.

5. The high-quality steel continuous casting functional refractory material stirred by inert gas according to claim 3 is characterized in that: The reinforcing agent is aluminum sulfate.

6. The method for preparing high-quality steel continuous casting functional refractory by inert gas agitation according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Raw material selection; S2, ingredients, add each group of ingredients according to the proportion; S3, mixing and granulating, using a granulator to mix and granulate; S4, screening, using a vibrating screen to screen the granulation raw materials; S5, trapping the material, sealing 75% of the raw materials; S6, mixing, using a horizontal mixing device to mix the finished raw materials and the remaining 25% of the raw materials evenly; S7, inspecting and determining the particle size, moisture content and green body density of the mixed raw materials; S8, forming, using die-casting equipment to press the mixed principle into a stopper rod blank; S9, drying, drying the formed green body; S10, firing, pushing the stopper rod blank into a high-temperature tunnel kiln for firing, and then cooling to room temperature before taking it out of the kiln; S11, processing, processing the outer circle and slag line thickness of the stopper rod; S12, spraying, spraying glaze on the outside of the stopper rod using an automatic glaze dipping device; S13. Inspection: Check the appearance, size and physical and chemical indicators of the finished product; S14. Qualified products are packaged and put into storage, and unqualified products are destroyed.

7. The method for preparing high-quality steel continuous casting functional refractory material by inert gas agitation according to claim 6, characterized in that: In S3, the raw materials need to be premixed and preheated before kneading. The premixing is performed by mixing the raw materials through a stirring device and preheating the premixed raw materials at a temperature of 70° C. to 80° C.

8. The method for preparing high-quality steel continuous casting functional refractory material by inert gas agitation according to claim 6, characterized in that: In the S5, 75% of the raw materials are placed in a silo or a material storage area and covered with plastic sheeting to ensure that the raw materials do not come into contact with water. The air temperature should be greater than 15°C and the raw materials are left to stand for more than 24 hours. At the same time, constant temperature and humidity are required, and the mud is placed in multiple layers to achieve a reasonable combination of mud materials and ensure the stability of mud material indicators.

9. The method for preparing high-quality steel continuous casting functional refractory material by inert gas agitation according to claim 6, characterized in that: The drying in step S9 includes natural drying and heating drying. The natural drying is drying at room temperature above 15° C. for more than 6 hours, and the heating drying is drying in a heating kiln at 110° C.-150° C. for 1-2 hours.

10. The method for preparing the high-quality steel continuous casting functional refractory material by stirring with inert gas according to claim 6, characterized in that: The sintering process comprises the following steps: S1, loading, pushing the stopper rod blank into the high temperature tunnel kiln; S2, heating, uniformly heating to 550℃-750℃ within 5 hours; S3, high temperature firing, the high temperature tunnel kiln is heated to 1550-1650℃ for firing within 4 hours; S4, heat preservation, heat preservation and firing at 1550-1650℃ for 18 hours to 24 hours; S5, cooling, uniformly cooling to 150℃-200℃ within 8 hours; S6. Cooling: Cooling to room temperature and taking the fired stopper rod out of the kiln.

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