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CN-122010533-A - Magnesia ladle nozzle brick for cord steel and preparation method thereof

CN122010533ACN 122010533 ACN122010533 ACN 122010533ACN-122010533-A

Abstract

The invention discloses a magnesia ladle nozzle brick for cord steel, which comprises, by weight, 47% -54% of 97% of fused magnesia, 7% -9% of forsterite, 12% -18% of fused spinel, 4% -6% of high-temperature sintering promoting powder, 5% -8% of ceramic plastic adhesive, 1% -3% of carbon-containing powder, 1% -3% of graphite, 1% -3% of boron carbide, 4% -6% of aluminum-magnesium alloy powder, 2% -4% of silicon powder, and 4% -6% of additional resin and 0.4% -0.5% of resin reinforcing agent. The invention aims to provide a magnesia ladle nozzle brick for cord steel, which has the advantages of reducing the porosity, improving the erosion resistance and the wear resistance, reducing the internal thermal stress of a blank body, avoiding microcracks and improving the thermal shock resistance stability, and a preparation method thereof.

Inventors

  • LU HONG
  • HANG WENMING
  • WANG YUANLIN

Assignees

  • 无锡市南方耐材有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The magnesia ladle nozzle brick for the cord steel is characterized by comprising the following components in percentage by weight: 97 percent of electric fused magnesia, namely 47 percent to 54 percent; 7% -9% of forsterite; 12% -18% of electrofused spinel; 4% -6% of high-temperature combustion promoting powder; 5% -8% of ceramic plastic adhesive; 1% -3% of carbon powder; 1% -3% of graphite; 1% -3% of boron carbide; 4% -6% of aluminum magnesium alloy powder; 2% -4% of silicon powder; In addition, 4% -6% of resin and 0.4% -0.5% of resin reinforcing agent are added.
  2. 2. The magnesia ladle nozzle brick for the cord steel, as claimed in claim 1, wherein the particle size distribution of each component adopts gradient collaborative design, and the specific requirements are as follows: 97 electric smelting magnesia, namely adopting a four-stage gradient design, wherein 3-1 mm particles account for 10% -15%, 2-1 mm particles account for 10% -17%, 1-0.5 mm particles account for 9% -12%, fine powder which is more than or equal to 200 meshes accounts for 12% -16%, and the total ratio of the four-stage particles accounts for 35% -38%; 1-0 mm of particles of forsterite; The electrofused spinel is 0.5-0 mm of fine particles; The high-temperature sintering promoting powder, the ceramic plastic adhesive, the boron carbide, the aluminum magnesium alloy powder and the silicon powder are more than or equal to 180 meshes; The powder contains carbon powder and graphite with 325 meshes.
  3. 3. The magnesium ladle nozzle brick for cord steel according to claim 2, wherein the weight percentage is as follows: The MgO content of the 97 electric smelting magnesia is more than or equal to 97 percent; The content of the forsterite is less than or equal to 40 percent of SiO 2 and the content of MgO is more than or equal to 45 percent; The content of Al 2 O 3 is more than or equal to 72 percent, and the content of MgO is more than or equal to 21 percent; the sintering promoting powder contains less than or equal to 30% of SiO 2 , more than or equal to 72% of Al 2 O 3 and has a refractoriness of more than 1800 ℃; the bulk density of the plastic adhesive is 450g/L; The carbon-containing powder contains 85% of residual carbon; the content of C in the graphite is more than or equal to 97%; the content of B 4 C is more than or equal to 90 percent; the aluminum magnesium alloy powder comprises 50+/-3% of Al and 7.0% of active metals Al and Mg; The Si content of the silicon powder is more than or equal to 97%; The carbon residue of the resin is 45+/-4%, the solid content is 75-80%, and the viscosity is 15000-18000 mpa.
  4. 4. A method of producing a magnesia ladle nozzle brick for cord steel according to any one of claims 1 to 3, comprising the steps of: s1, gradient mixing; s2, high-pressure forming; s3, gradient drying; S4, accurate sintering; s5, processing; S6, checking a finished product.
  5. 5. The method for preparing the magnesia ladle nozzle brick for the cord steel according to claim 4, wherein the gradient mixing in the step S1 comprises the following steps: 97 electric smelting magnesia particles (3-1 mm, 2-1 mm and 1-0.5 mm) are added into a high-speed mixer, and dry-mixed for 3-6 minutes to form a uniform framework; adding resin and a resin reinforcing agent, uniformly mixing for 5-8 minutes, and ensuring that the liquid bonding agent uniformly coats the surfaces of the particles; And sequentially adding 97 fused magnesia fine powder, forsterite, fused spinel, high-temperature sintering promoting powder, ceramic plastic adhesive, carbon powder, graphite, boron carbide, aluminum magnesium alloy powder and silicon powder, and continuously mixing for 10-30 minutes to form uniform and compact pug, so that the full contact of all component interfaces is ensured.
  6. 6. The preparation method of the magnesia ladle nozzle brick for the cord steel, which is disclosed in claim 4, is characterized in that the high-pressure molding in S2 is realized by precisely weighing pug according to preset size by using a spiral brick press with the weight of more than 1000 tons, and adding the pug into a custom mold for high-pressure molding.
  7. 7. The method for preparing the magnesia ladle nozzle brick for the cord steel, which is disclosed in claim 5, is characterized in that the finished brick blank in the step S2 is also required to carry out full-size detection on each brick, namely, the overall dimension, the flatness and the diagonal line, checking the single weight, the porosity and the volume density of 10% of products in each shift, immediately scrapping unqualified products and tracing the reasons, and ensuring the consistency of blanks.
  8. 8. The method for manufacturing a magnesia ladle nozzle brick for a cord steel according to claim 4, wherein the gradient drying in the step S3 comprises the steps of: Naturally drying the formed blank for 8-12 hours, and releasing surface moisture; Transferring the mixture into a drying kiln to perform gradient heating drying, wherein the total time is 40-60 hours, the temperature is uniformly increased to 80 ℃ in 1 hour, the temperature is kept for 12 hours, and then the temperature is uniformly increased to 190 ℃ in 24 hours, and the temperature is kept for 20 hours.
  9. 9. The method for manufacturing a magnesia ladle nozzle brick for cord steel according to claim 4, wherein in the step S4, the precision firing comprises the following steps: pushing the dried blank into a medium-high temperature tunnel kiln, heating to 580 ℃ plus or minus 20 ℃ at a constant speed within 15-20 hours, and preserving heat for 15-20 hours; and adopting a uniform cooling process, and slowly cooling to room temperature within 20 hours.
  10. 10. The method for preparing magnesia ladle nozzle bricks for cord steel according to claim 4, wherein the processing treatment in the step S5 comprises the steps of finishing the brick body and sleeving the finished brick with an iron shell.

Description

Magnesia ladle nozzle brick for cord steel and preparation method thereof Technical Field The invention relates to the field of refractory materials with inorganic materials as base materials, in particular to a magnesia ladle nozzle brick for cord steel and a preparation method thereof. Background The cord steel is used as a radial core framework material of the tire, and has extremely severe requirements on purity of molten steel, inclusion control and casting stability. The main stream ladle nozzle bricks in the current industry mainly comprise aluminum zirconium carbon, aluminum carbon nozzle bricks and inlaid zirconium ring nozzle bricks, but the aluminum zirconium carbon nozzle bricks have technical bottlenecks which are difficult to break through in high-end steel casting, wherein the aluminum zirconium carbon nozzle bricks show good thermal shock resistance and wear resistance in common steel casting, but when calcium treatment steel is cast, al 2O3 and SiO 2 contained in the aluminum zirconium carbon nozzle bricks are easy to react with CaO in molten steel at low temperature to generate low-melting matters, nozzle clamping steel is easy to be caused after molten steel flushing, the quality of molten steel is seriously influenced, the zirconia nozzle bricks have excellent erosion resistance and oxidation resistance, but the problem of melting loss still exists in aluminum killed steel casting, the zirconia raw materials have high price, the cost of ton steel refractory is high, and large-scale popularization is difficult. The existing magnesia nozzle brick has the advantages of raw material cost, but is limited by inherent characteristics of large thermal expansion coefficient and high sintering difficulty of periclase, generally has the problems of poor thermal shock resistance and insufficient high-temperature strength, has short service life, cannot meet the requirement of continuous and stable casting of high-end steel such as cord steel, has a small number of applications only in Europe, and almost has blank domestic market. The industry faces the double technical problems of erosion resistance and cost balance and thermal shock resistance and high-temperature strength synergy for a long time, and development of a novel water gap brick with high performance, low cost and long service life is needed to break through the technical bottleneck of refractory materials for high-end steel casting. Disclosure of Invention In order to solve the problems, the invention aims to provide the magnesia ladle nozzle brick for the cord steel, which has the advantages of reducing the porosity, improving the erosion resistance and the wear resistance, reducing the thermal stress in a blank body, avoiding microcracks and improving the thermal shock resistance and a preparation method thereof. According to one aspect of the invention, there is provided a magnesia ladle nozzle brick for cord steel, comprising the following components in percentage by weight: 97 percent of electric fused magnesia, namely 47 percent to 54 percent; 7% -9% of forsterite; 12% -18% of electrofused spinel; 4% -6% of high-temperature combustion promoting powder; 5% -8% of ceramic plastic adhesive; 1% -3% of carbon powder; 1% -3% of graphite; 1% -3% of boron carbide; 4% -6% of aluminum magnesium alloy powder; 2% -4% of silicon powder; In addition, 4% -6% of resin and 0.4% -0.5% of resin reinforcing agent are added. In some embodiments, the particle size fractions of the components are designed in a gradient co-operation mode, and the specific requirements are as follows: 97 electric smelting magnesia, namely adopting a four-stage gradient design, wherein 3-1 mm particles account for 10% -15%, 2-1 mm particles account for 10% -17%, 1-0.5 mm particles account for 9% -12%, fine powder which is more than or equal to 200 meshes accounts for 12% -16%, and the total ratio of the four-stage particles accounts for 35% -38%; 1-0 mm of forsterite particles; 0.5-0 mm of fine particles of electrofused spinel; high-temperature sintering promoting powder, ceramic plastic adhesive, boron carbide, aluminum magnesium alloy powder and silicon powder are more than or equal to 180 meshes; Contains carbon powder and graphite of 325 meshes. In some embodiments, the weight percentages are: 97 percent of electric melting magnesia, wherein the MgO content is more than or equal to 97 percent; Forsterite: siO 2 content is less than or equal to 40% and MgO content is more than or equal to 45%; the content of Al 2O3 is more than or equal to 72 percent, and the content of MgO is more than or equal to 21 percent; The sintering promoting powder contains SiO 2 content less than or equal to 30%, al 2O3 content more than or equal to 72% and fire resistance higher than 1800 ℃; carbon powder and residual carbon content 85%; The content of C is more than or equal to 97 percent; The content of B 4 C is more than or equal to 90 percent; aluminum magnesium alloy powder with Al conte