JP3492885B2 - Slide gate plate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide gate plate used for controlling the flow rate of molten pig iron and molten steel in a steel making process.

[0002]

2. Description of the Prior Art Plates for slide gates are used to control the flow rate of molten steel in secondary processing of ladle and continuous casting,
Widely used as an indispensable refractory material in the steelmaking process.
Since the slide gate plate is used as a member for controlling the molten steel flow, a very high function is required. For example, in terms of materials, it is desired to have excellent characteristics in response to various severe conditions.

The sliding gate plate has physical effects such as rapid thermal shock and wear due to molten steel flow, and
It is physically and chemically corroded by molten steel and molten steel slag. Therefore, it is necessary that the slide gate plate has characteristics such as thermal shock resistance, corrosion resistance and strength.

Various studies have been conducted in order to equip such a slide gate plate with various characteristics in a well-balanced manner. Recently, alumina-carbon, alumina-zirconia, which has the most stable durability,
Carbon-based plates are widely used in the steelmaking process.

Generally, in order to manufacture a slide gate plate, for example, an alumina type, a zirconia type, a silica type,
A thermosetting resin such as a phenol resin, which is a binder, is added and kneaded to an inorganic material such as carbon or silicon carbide,
A step of firing after molding is adopted. Depending on the application, pitch or tar impregnation may be applied after firing to improve the characteristics.

By the way, in order to improve the thermal shock resistance, it has been conventionally practiced to use a large amount of a raw material having a low coefficient of thermal expansion such as silica, carbon or silicon carbide. However, since such a raw material easily reacts with molten steel or forms a low melting point compound, if excessively mixed in the slide gate plate, there is a problem that corrosion resistance is significantly lowered.

Further, since the carbon-based raw material or the silicon carbide-based raw material has a relatively high thermal conductivity, when these raw materials are used alone or in combination with other raw materials, the thermal conductivity of the product itself is increased. Get higher As a result, the temperature of the entire slide gate plate tends to excessively rise when receiving steel, and there is a possibility that seizure may occur near the flow holes through which the molten steel directly flows. Further, when narrowing down the slide gate plate, there is a problem that the viscosity of the molten steel does not increase at the sliding portion, the molten steel enters the gap between the plates that are crimped, and it becomes difficult to control the flow rate of the molten steel.

[0008]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a slide gate plate provided with a carbon-containing refractory which is prevented from being burnt in the vicinity of a molten steel flow hole and has improved steel leakage between crimping surfaces. Is.

[0009]

The slide gate plate according to the present invention is obtained by adding a desired amount of a binder to at least one or more aggregates selected from refractory inorganic materials and carbon, followed by kneading, molding and firing. The carbon-containing refractory material obtained by the above method has a thermal conductivity of 2 to 15 W /
It is characterized by being m · K.

In the present invention, it is preferable that the refractory material contains a carbon component in an amount of 2 to 15% by weight. In the present invention, it is preferable that the refractory or the refractory in which the carbon component is specified contains a silicon carbide component in an amount of 1.0 to 10% by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
This slide gate plate is provided with a carbon-containing refractory obtained by adding a desired amount of a binder to at least one kind of aggregate selected from refractory inorganic materials and carbon, and kneading, molding and firing. This refractory has a thermal conductivity of 2 to 15 W / m · K.

Examples of the refractory inorganic material include alumina-based raw materials, zirconia-based raw materials, and silica-based raw materials, which are used alone or in the form of a mixture of two or more kinds. If necessary, a silicon carbide based raw material may be used as the refractory inorganic material.

The thermal conductivity of the refractory material is defined for the following reasons. Thermal conductivity of 2 W / m
If it is less than K, the thermal shock resistance may decrease. On the other hand, if the thermal conductivity exceeds 15 W / m · K, the thermal conductivity of the refractory itself becomes too high, and the temperature of the entire slide gate plate tends to overheat when receiving steel. When baking occurs or when the sliding gate plate is narrowed down, the viscosity of the molten steel does not increase at the sliding portion, and the molten steel may enter the gap between the pressure-bonded plates, making it difficult to control the flow rate of the molten steel. More preferable thermal conductivity of the carbon-containing refractory is 4 to 10 W / m · K.

The carbon component in the refractory material is
It is preferable to contain 2 to 15% by weight. If the content of the carbon component is less than 2% by weight, the thermal shock resistance of the slide gate plate is significantly reduced. On the other hand, when the content of the carbon component exceeds 15% by weight, a reaction with molten steel is likely to occur rapidly in the flow holes of the slide gate plate, wear damage progresses, and durability deteriorates. The more preferable content of the carbon component is 4 to 10% by weight.

The silicon carbide component in the refractory is 1.0 to
It is preferable to contain 10% by weight. When the content of the silicon carbide component is less than 1% by weight, oxidation easily proceeds. On the other hand, when the content of the above-mentioned silicon carbide component exceeds 10% by weight, a reaction with molten steel is likely to occur rapidly in the flow holes of the slide gate plate and wear damage progresses.
The durability is reduced. The more preferable content of the silicon carbide component is 1 to 5% by weight.

According to the present invention described above, carbon having a refractory inorganic material such as an alumina raw material, a zirconia raw material, and a silica raw material and a carbon raw material, for example, an alumina-carbon type or an alumina-zirconia-carbon type carbon is used. Equipped with a refractory material containing 2 to 15 W /
By defining the range of m · K, it is possible to obtain a long-life sliding gate plate that can prevent seizure in the vicinity of the molten steel flow hole and that has improved steel leakage between crimping surfaces.

In particular, a slide gate plate provided with a carbon-containing refractory having a carbon component or a silicon carbide component specified within a predetermined range is further improved in prevention of seizure in the vicinity of the molten steel flow hole and in leakage steel between pressure-bonded surfaces. It will be noticeable.

[0018]

EXAMPLES Examples of the present invention will be described in detail below. (Examples 1 to 5) First, an electrofused zirconia-based raw material as primary particles, sintered alumina, a carbon-based raw material, and metallic silicon powder were used, and if necessary, a silica-based raw material and a silicon carbide-based raw material were used, and a binder was used. As the above, a phenol resin was blended in the ratio shown in Table 1 below, and these raw materials were kneaded using a wet pan to prepare five kinds of kneaded powder. Subsequently, these kneaded powders were molded into a slide plate shape by a friction press device to prepare a molded body. Subsequently, these molded bodies are dried at 200 ° C. to volatilize volatile components,
It was fired at a temperature of 1100 ° C. in a reducing atmosphere filled with coke powder. The content and thermal conductivity of SiC and C of these refractories are shown in Table 1 below. The thermal conductivity of five samples cut out from the refractory was measured by the laser flash method for n number of thermal conductivity, and the maximum and minimum measured values were excluded, and the remaining 3 samples It was determined from the average value of the measured values (n number).

Next, a band-shaped iron skin was fitted around the refractory material and the sliding surface was processed to manufacture five types of slide gate plates. (Comparative Examples 1 to 3) First, an electro-fused zirconia-based raw material as primary particles, sintered alumina, a carbon-based raw material, and metallic silicon powder are used, and if necessary, a silica-based raw material and a silicon carbide-based raw material are used, and a binder is used. As the above, a phenol resin was blended in a ratio shown in Table 2 below, and these raw materials were kneaded using a wet pan to prepare five kinds of kneaded powder. Subsequently, these kneaded powders were molded into a slide plate shape by a friction press device to prepare a molded body. Subsequently, these molded bodies are dried at 200 ° C. to volatilize volatile components,
It was fired at a temperature of 1100 ° C. in a reducing atmosphere filled with coke powder. The content and thermal conductivity of SiC and C of these refractories are shown in Table 2 below. The thermal conductivity was measured by the same method as in Examples 1-5.

Next, a strip-shaped iron skin was fitted around the outer periphery of each of the refractory materials, and the sliding surface was processed to manufacture three types of slide gate plates. Obtained Examples 1-5
And 100 slide gate plates of Comparative Examples 1 to 3.
It was attached to a ton ladle and a practical test was conducted to measure the number of times of use and the amount of damage near the molten steel circulation hole. The results are also shown in Tables 1 and 2 below.

FIG. 1 shows the relationship between the thermal conductivity of carbon-containing refractories incorporated in the slide gate plates of Examples 1 to 5 and Comparative Examples 1 to 3 and the amount of damage in the actual machine test.

[0022]

[Table 1]

[0023]

[Table 2]

As is clear from Tables 1 and 2 and FIG. 1, the slide gate plates of Examples 1 to 5 provided with the carbon-containing refractory having a thermal conductivity of 2 to 15 W / mK have a thermal conductivity of It can be seen that, compared with the slide gate plates of Comparative Examples 1 to 3 provided with the carbon-containing refractory material outside the above range, the damage amount of the molten steel flow hole proximity protection is low and the service life is long.

[0025]

As described above, according to the present invention, a long-life slide having a carbon-containing refractory material in which burning damage in the vicinity of molten steel flow holes is prevented and which has improved steel leakage between crimping surfaces, etc. A gate plate can be provided.

[Brief description of drawings]

FIG. 1 shows Examples 1 to 5 and Comparative Examples 3 to 3 according to the present invention.
FIG. 6 is a characteristic diagram showing the relationship between the thermal conductivity of the refractory material of the slide gate plate in FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Watanabe 1 Nanto, Ogakie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd.Kariya Works (72) Inventor Ken Kimura 1st, Nanto, Ogakie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd. Kariya Factory (56) Reference JP-A-53-119905 (JP, A) JP-A-57-27971 (JP, A) JP-A-9-202667 (JP, A) JP-A-10-52750 (JP, A) JP-A-6-166562 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C21C 7/00 C04B 35/00 C21C 5/46 103 F27D 3/14 B22D 41/32

Claims (3)

(57) [Claims] 1. A carbon-containing refractory material obtained by adding a desired amount of a binder to at least one or more aggregates selected from refractory inorganic materials and a carbon-based raw material, and kneading, molding and firing the mixture. A slide gate plate characterized in that the refractory has a thermal conductivity of 2 to 15 W / mK. 2. The slide gate plate according to claim 1, wherein the refractory material contains 2 to 15% by weight of a carbon component. 3. The refractory has a silicon carbide component of 1.0 to
The content of claim 1 or 2 is 10% by weight.
The described slide gate plate.