JPH05318040A - Device for sealing molten metal on cooling roll - Google Patents

Abstract

PURPOSE:To effectively prevent the leakage of molten metal from between a cooling roll and a pouring nozzle, in a continuous casting method for strip. CONSTITUTION:At the time of producing a metal strip by rapidly solidifying the molten metal on the circumferential surface of the rotating cooling roll 14, a ceramic fiber felt layer 20 is arranged on the surface of the pouring nozzle with the cooling roll 14 and the metal strip 30 is interposed in between this ceramic fiber felt layer 20 and the cooling roll 14 so that the tip part retreats by 1-5mm from the tip part of the pouring nozzle. By this method, the leakage of the molten metal at the time of continuous casting and at the same time, the formation of defect, such as crack, seam, recessed part, can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for sealing molten metal on a cooling roll, and more particularly to a sealing device in which a ceramic fiber bar felt and a metal plate are interposed between a cooling roll and a casting nozzle.

[0002]

2. Description of the Related Art Conventionally, it has been important to seal molten metal between a rotating cooling roll and a casting nozzle in a continuous thin plate casting method, and many proposals have been made for a sealing device and a mechanism therefor. .. For example, JP-A-63-1010
In Japanese Patent No. 53, there is disclosed an example in which a stretchable ceramic fiber felt is provided on the casting nozzle side.

However, when the cushioning material according to this proposal is actually used, the strength is insufficient, and the cushioning material may be damaged during use and may be caught in the product to cause a flaw in the product. In order to eliminate such a defect, Japanese Patent Application Laid-Open No. 2-117749 discloses a cloth-like body made of an inorganic material as a sealing material on a sliding surface such as a casting nozzle for a cooling roll in order to eliminate defects such as indentation flaws. Proposed to be used.

However, even with this material, it is practically difficult to obtain an extremely thin and heat-resistant material that withstands the frictional force between the roll and the pouring nozzle and seals.
Moreover, since they are expensive and are originally consumables, the increase in product cost cannot be avoided. In addition, although woven cloth-like materials that meet the purpose are also scattered, it is necessary to perform cutting work according to the actual product in order to install it so that it does not project into the casting space formed by the casting nozzle and rolls. Loses its strength and breaks due to the frictional force with the rolls, which causes leakage of water and indentation flaws.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an effective sealing means for preventing leakage of molten metal between a cooling roll and a pouring nozzle in a continuous casting method for thin plates. is there.

[0006]

Here, the present inventors
Various studies have been repeated to solve such problems, and the following findings have been obtained. The molten metal is basically sealed with a stretchable felt made of ceramic fiber to prevent leakage of molten metal. The lack of strength of the ceramic fiber felt can be solved by protecting it with a metal plate.

The hardness of the metal plate used for reinforcement is the same as or lower than the surface hardness of the cooling roll so as not to damage the cooling roll. The arrangement relationship between the metal plate and the ceramic fiber felt should be set back by 1 to 5 mm from the casting space.
The quality of the cast sheet is ensured. The portion of the ceramic fiber felt that comes into contact with the molten metal is protected by a ceramic bond to avoid the loss of the felt during casting and to exert the reinforcing effect of the ceramic fiber felt that is not protected by the metal plate.

Therefore, the gist of the present invention is to provide a ceramic fiber felt layer on the surface of a casting nozzle which is in contact with the cooling roll in an apparatus for producing a thin metal plate by rapidly solidifying molten metal on the peripheral surface of a rotating cooling roll. And the tip is 1 to 5 from the tip of the casting nozzle between the ceramic fiber felt layer and the cooling roll.
This is a molten metal sealing device in which a thin metal plate is interposed so as to retreat by mm.

According to a preferred aspect of the present invention, the surface of the ceramic fiber felt layer which is in contact with the molten metal may be covered with a ceramic bond layer. Further, the metal plate preferably has a surface hardness equal to or less than the surface hardness of the rotating cooling roll.

[0010]

Next, the operation of the present invention will be described. 1 to 3 are cross-sectional views for explaining an aspect of the method according to the present invention, FIG. 1 is a plan view, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. It is a figure. As can be seen from FIG. 1, the tip of the tundish 10 has a bottom 12 of the casting nozzle.
There is provided a casting nozzle 12 in which b and the casting nozzle side wall 12a are integrally formed, and the casting space is defined by the tip of the casting nozzle bottom 12b and the casting nozzle side wall contacting the cooling roll 14 respectively, and the casting space is injected. The molten metal (not shown) is regulated so that it will not overflow.

The molten metal leakage that occurs during continuous casting occurs at the contact surface between the side wall 12a and the cooling roll 14 and the contact surface between the casting nozzle bottom portion 12b and the cooling roll 14, but usually the problem is the casting nozzle bottom portion 12b. This is a leak of hot water at the contact surface between the cooling roll 14 and the cooling roll 14.

FIG. 2 shows a ceramic fiber felt layer.
It is a diagram showing the arrangement of the nozzle 20 and 20 and the metal plate 22,
The ceramic fiber felt layer 20 has a nozzle bottom 12b.
And the nozzle side wall 12a is provided on the contact surface with the cooling roll 14, the metal plate 30 is fixed to the lower part of the tundish 10 and advances toward the nozzle side, and the ceramic fiber felt layer 20 and the cooling roll 14 are connected. It is located in between.

FIG. 3 shows a sectional structure of the casting nozzle 12, in which a ceramic fiber felt layer 20 is adhered to the lower surface of the nozzle tip 24 which is usually made of a refractory, and a contact surface with the cooling roll 14 is provided. Is composed of. The ceramic fiber felt layer 20 does not come into direct contact with the molten metal, and a ceramic bond layer 28 is provided at the tip thereof. In the drawing, there is a space between the ceramic fiber felt layer 20 and the cooling roll 14, but in reality, this portion is sealed in a contact state and continuous casting is performed.

Here, according to the present invention, a metal plate 30 is provided between the ceramic fiber felt layer 20 and the cooling roll 14.
Are disposed so that the tip thereof is at a position retracted by 1 to 5 mm from the tip of the casting nozzle, in this case the tip of the ceramic bond layer 28.

The ceramic fiber felt used in the present invention is an alumina fiber, a silicon carbide fiber, a high silica glass fiber or the like, and may be, for example, a product commercially available under the trade name "Arsen". Further, the ceramic bond is one in which particles of alumina, silica, ZrO ₂ or the like are dispersed in a binder, and this may be also commercially available under the trade name of “Sumiceram”.

Further, the metal plate is not particularly limited as long as it has a surface hardness equal to or lower than the surface hardness of the cooling roll, but a material having excellent heat resistance, for example, a stainless steel plate is generally preferable. A plate thickness of 0.05 to 0.3 mm is generally sufficient. As described above, by interposing the ceramic fiber felt layer and the metal plate between the casting nozzle and the cooling roll according to the present invention, the following synergistic effect is produced.

In the thin plate continuous casting method, molten metal oxides adhere to the casting rolls, and the heat transfer coefficient changes depending on the adhered state, which may cause uneven thickness of the slab and cracks. For this reason, various attempts have been made to make these deposits uniform. For example, in Japanese Patent Laid-Open No. 3-118944, it is proposed that the deposit is not simply scraped off, but a uniform thin film is formed. However, by using a metal plate as in the present invention, Since the metal plate is pressed against the surface of the chill roll, it has the effect of smoothing out the oxide scale. This made it possible to manufacture a slab with a uniform thickness and prevent defects such as cracks, wrinkles, and dents.

[0018]

EXAMPLES The operation and effects of the present invention will be described more specifically by way of examples. In this example, continuous casting of SUS 304 was carried out for 5 minutes using the apparatus shown in FIGS. The cooling roll is made of stainless steel and has an outer diameter of 600 mm and a surface hardness of Hv.
180, two kinds of stainless steel plates (plate thickness 0.1 mm) with different surface hardness were used for the metal plate. The results are summarized in Table 1.

[0019]

[Table 1]

[0020]

As described above, according to the present invention, the metal plate is used for reinforcing the ceramic fiber felt layer and smoothing the deposits on the cooling roll. As an effect of using,
The following points can be mentioned. In the conventional example, it was necessary to cut and process the inorganic sealing material on-site in accordance with the actual dimensions so that the inorganic sealing material does not project into the casting space, that is, it does not project beyond the tip of the casting nozzle. The metal plate used in (1) can be mounted by retracting from the casting space by 1 to 5 mm, so such a need is not necessary. The metal plate processed in the factory can be used as it is. Therefore, the setup time required for mounting can be shortened, and the operability can be improved. The metal plate is a general material, and the material cost is low. It can be reused and the total cost can be significantly reduced. Due to the synergistic effect with the ceramic fiber felt layer, the sealing effect is sufficient and the life can be further extended. The deposits on the cooling roll can be effectively smoothed, and the quality of the cast slab can be improved.

[Brief description of drawings]

1 is a plan view of an apparatus for carrying out the method according to the invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

10: Tundish 12: Nozzle 12b: Bottom of casting nozzle 14: Cooling roll 12a: Side weir 20: Ceramic fiber felt layer 28: Ceramic bond layer 30: Metal plate

Claims (3)

[Claims] 1. An apparatus for producing a thin metal sheet by rapidly solidifying molten metal on a peripheral surface of a rotating cooling roll, wherein a ceramic fiber felt layer is disposed on a surface of a casting nozzle in contact with the cooling roll, and the ceramic fiber felt layer. 2. A molten metal sealing device, characterized in that a thin metal plate is interposed between the cooling roll and the cooling roll so that the tip of the casting nozzle is retracted from the tip of the casting nozzle by 1 to 5 mm. 2. A surface of the ceramic fiber felt layer in contact with the molten metal is coated with a ceramic bond layer,
The device according to claim 1. 3. The apparatus according to claim 1, wherein the metal plate has a surface hardness equal to or less than that of a rotating cooling roll.