JPH07115957B2 - Refractory manufacturing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a refractory material suitable for use as a casting member such as a sliding gate plate.

2. Description of the Related Art Conventionally, carbon-containing refractories have been widely used because of their excellent spalling resistance.

Further, in order to further improve the spalling resistance, it has been proposed to include aluminum fibers in the refractory material.

For example, in JP-A-60-200866, the length is 1 to 10
mm and diameter of 10-150 μm metal aluminum fiber and / or aluminum alloy fiber 1-15 wt%
And a powder containing 1 wt% or more of carbon powder are kneaded and molded, and then fired in a non-oxidizing atmosphere of 1000 ° C. or more. In this case, aluminum carbide (Al ₄ C ₃ ) is produced by reacting with the carbon powder.

In JP-A-61-136966, a mixture of a refractory raw material containing 5 to 60% of carbon and an organic binder was added, and aluminum short fibers were added in an amount of 0.1 to 30 wt% based on the refractory raw material. After that, a method of heat treatment is disclosed. In this case, aluminum carbide (Al ₄ C ₃ ) having a high melting point (2200 ° C.) is generated by reacting with carbon at a high temperature. Further, by adding the metal powder, it adheres to the surface of the aluminum short fibers to promote the Susa effect. It also enhances the bond strength between the aluminum short fibers and the matrix.

Problems to be Solved by the Invention When a refractory manufactured by the conventional method as described above is used at high temperature, infiltration of molten aluminum into surrounding tissues due to thermal history and accompanying aluminum oxide (Al ₂ O ₃ ) and aluminum carbide (Al ₄ C ₃ ) conversion progresses. Therefore,
At the beginning of use, the refractory material has spalling resistance, but if it is used many times, the spalling resistance is significantly reduced.
The decrease in spalling resistance causes expansion of cracks in the refractory material, which is a serious problem.

OBJECT OF THE INVENTION It is an object of the present invention to provide a method for producing a refractory having a long service life, which is excellent in durability and does not extremely deteriorate in spalling resistance even when used many times.

SUMMARY OF THE INVENTION The present invention has a gist of a method for manufacturing a refractory material described in claim 1 in order to achieve the above object.

Means for Solving the Problems In the present invention, carbon powder is not used as an aggregate raw material. The product contains carbonized binders and, if necessary, impregnated pitches as a carbon component, but in any case, when compared to refractory containing carbon powder as an aggregate raw material, carbon It exhibits excellent corrosion resistance over a long period of time against ultra-low carbon steel, which has a strong tendency to erode.

By not using carbon powder as an aggregate raw material,
Even when the refractory is actually used at a high temperature, the carbonization reaction of the aluminum fiber becomes extremely slow, and the metallic state is maintained for a long time.

In the present invention, a specific metal powder is included in a refractory containing no carbon powder as an aggregate raw material and containing metal aluminum fibers. The addition of such metal powder does not cause carbonization of the metal aluminum fiber as seen in the prior art, but rather the metal powder comes into contact with the metal aluminum fiber and the metal powder alloys with the aluminum fiber, whereby the metal aluminum It is possible to prevent oxidation and carbonization of the fiber itself. In other words, even when repeatedly subjected to a heat history at a temperature far exceeding the melting point (660 ° C) of metallic aluminum fiber in actual use, the viscosity of aluminum increases during melting, so that the surrounding tissue is infiltrated and the associated oxidation and carbonization occur. The fiber morphology is maintained in the metallic state with almost no occurrence of the phenomenon. Therefore, the effect of adding the metal aluminum fiber is repeatedly exhibited. Therefore, the deterioration of the spalling resistance due to the increase in the number of times of use, which has occurred in the prior art, is reduced.

As the metal powder, one having a low vapor pressure is desirable, and one having a high vapor pressure, such as Mg, evaporates at the use temperature of the refractory, and the effect of increasing the viscosity of aluminum cannot be obtained. Such metal powder is a metal powder of Si, Fe, Cr, Ti, Cu, Co, Mn having a particle size of 100 mesh or less,
Powders of those alloys, 0.5-10, alone or in combination.
Use by weight%.

If the metal powder that does not come into contact with the metal aluminum fibers also has the effect of improving the oxidation resistance of the refractory, the metal powder of Si is most desirable in terms of cost.

The diameter and length of metal aluminum fiber is 20 ~
The thickness is 200 μm and 1 to 7 mm, and the addition amount is 0.2 to 10% by weight. The addition amount and size of the metallic aluminum fiber are determined in consideration of the effect of addition and the corrosion resistance and dispersibility. This also applies to the metal powder.

Explaining the firing temperature, if it is above the melting point, it will not oxidize or carbonize, but it will infiltrate into the surrounding tissue, and the fiber form in the metal state will not be maintained, resulting in 950 ° C.
The above is not preferable because it becomes remarkable.

When heat-treated at the melting point of aluminum or 950 ° C,
It is preferable to impregnate the voids from which the binder has been impregnated with tar pitch, synthetic resin, or the like, because the voids are filled, the corrosion resistance and oxidation resistance are improved, and the infiltration of the metallic aluminum fibers into the surrounding tissues during actual use is stopped.

Instead of mixing the metal aluminum fiber and the metal powder at the same time as the binder and the like, the metal aluminum fiber may be surface-treated with the metal powder in advance. In that case, the metal aluminum fiber is Si, F
The surface treatment can be performed with one or more of e, Cr, Ti, Cu, Co, and Mn metals. The simplest surface treatment method is to mix the metal aluminum fibers with the metal powder before kneading with the aggregate.

The aggregate is appropriately selected according to the application. For example, for sliding gate plates, use sintered alumina and / or synthetic mullite, and for ladle bricks use sintered spinel, magnesia clinker, zircon and / or sintered alumina.

As the binder, synthetic resin such as tar, pitch or phenol resin is used.

The present invention is a sliding gate plate for casting,
It can be applied to the production of refractory materials such as nozzles, converters, and ladle lining materials.

By using aggregates that do not contain carbon powder,
Carbonization of metal aluminum fiber by carbon powder does not occur. The carbon formed by carbonizing the binder and the carbon in the impregnated tar pitch slightly react with the aluminum fiber or the metal powder, but such a reaction is
It is extremely unlikely to occur as compared with the conventional reaction with carbon powder used as an aggregate raw material.

By adding the metal powder, it is possible to suppress the infiltration of the metal aluminum fiber into the surrounding tissue at high temperature. Therefore, even if the refractory material is used at a high temperature for a long time, the spalling resistance does not extremely deteriorate.

Examples 1 to 6 and Comparative Examples 1 to 8 At various compounding ratios shown in Table 1, sintered alumina and synthetic mullite having a particle size of 3 mm or less, carbon powder having a particle size of 200 mesh or less, and a particle size of 100 Si powder below mesh and aluminum metal fiber with a diameter of 50 μm and length of 3 mm were mixed with a binder (phenol resin) in a mixer and molded at a molding pressure of 1500 kg / cm ² at various temperatures (400-1000). Heated at (° C) to make a sliding gate plate. The atmosphere during the heat treatment was a non-oxidizing atmosphere. Except for Example 4, impregnation treatment was performed with tar pitch in order to improve the corrosion resistance and the oxidation resistance after firing.

For the sliding gate plate described above, various properties such as bending strength, spalling resistance, and practical life at room temperature and 1400 ° C were measured. The measurement results are shown in Table 1.

In Table 1, the spalling resistance was measured by heating at 1400 ° C. for 10 minutes and then cooling with water three times. As the practical life, the number of possible charges in continuous casting containing at least 50% of ultra low carbon steel is shown.

FIG. 1 is a photograph showing the internal microstructure when the sliding gate plate of Example 1 was used 16 times.

Examples 7 to 18 and Comparative Examples 9 to 16 Sintered alumina and synthetic mullite having a particle size of 3 mm or less, various metal powders having various particle sizes, and various diameters at the compounding ratios shown in Tables 2a and 2b. And length of metal aluminum fiber are kneaded with a binder (phenolic resin) in a mixer, molded at a molding pressure of 1500 kg / cm ² , then heat-treated at 900 ° C in a non-oxidizing atmosphere, and then tar pitch after firing. Impregnated to produce a sliding gate plate.

The results of measuring the characteristics of Examples 7 to 18 and Comparative Examples 9 to 16 are shown in Tables 2a and 2b.

FIG. 2 is a photograph showing the internal microstructure when the sliding gate plate of Comparative Example 13 was used 7 times.

Examples 19-21 and Comparative Examples 17-19 Sintered spinel with the compounding ratios and dimensions shown in Table 3,
Magnesia clinker, zircon, and sintered alumina are used as aggregate raw materials, metal aluminum fiber, Si metal powder, and binder (phenol resin) are added, and they are kneaded with a mixer and molded at a pressure of 3000 kg / cm ² at 250 ° C. Was heat-treated in a non-oxidizing atmosphere to produce ladle bricks.

When the characteristics of Examples 19 to 21 and Comparative Examples 17 to 19 were measured, the results shown in Table 3 were obtained.

[Brief description of drawings]

FIG. 1 is a photograph showing a cross section of a metal aluminum fiber inside a refractory produced by the method of the present invention, and FIG.
The figure is a photograph showing a cross-sectional portion of a metal aluminum fiber inside a refractory which is a comparative example outside the scope of the present invention in comparison with FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kensei Kondo No. 1 Minamito, Ogakie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd. Kariya factory (72) Inventor Riki Iwasawa, No. 1 Minamifuji, Ogakie-cho, Kariya city, Aichi prefecture Lamix Co., Ltd., Kariya Plant (56) References JP-A-60-81068 (JP, A) JP-A-61-146773 (JP, A)

Claims (1)

[Claims] 1. A refractory aggregate 80-9 containing no carbon powder.
9.3% by weight, 0.2 to 10% by weight of metal aluminum fiber having a diameter of 20 to 200 μm and a length of 1 to 7 mm, and Si, Fe, Cr, Ti, Cu, Co, Mn having a particle size of 100 mesh or less. One or more of the metal powders and their alloys of 0.5
A method for producing a refractory, which comprises kneading 10 to 10% by weight with a binder, and heat-treating the mixture after molding in a non-oxidizing atmosphere and at a temperature of 950 ° C or lower.