JPH06297114A - Apparatus for producing metal strip - Google Patents

Abstract

PURPOSE:To provide a metal strip producing apparatus in which the cut-off of outer gas flow caused by a coolng roll can favorably be attained. CONSTITUTION:In the metal strip producing apparatus having the cooling roll 5 rotated at high speed and a nozzle 4 for introducing the discharge of the molten metal 2 on the surface of the cooling roll, in the upstream side in the rotating direction of the roll from the discharging position of the molten metal with the nozzle 4, a shield plate 10 extended in the axial direction of the cooling roll with a width wider than the width of the molten metal film discharged on the cooling roll surface, is arranged substantially, near the cooling roll surface. Further, gas piping 10 for supplying gas so that the pressure in the downstream zone of the shield plate becomes atmospheric pressure or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a metal ribbon by rapidly solidifying a molten metal by using a cooling roll cooled by supplying a liquid to the inside of the roll, and a paddle in a pouring section thereof. To stabilize the quality of the obtained ribbon and improve the quality of the obtained ribbon.

[0002]

2. Description of the Related Art Conventionally, when a molten metal is continuously supplied from a nozzle onto a cooling roll which rotates at a high speed, and a rapid cooling solidification is forced on the roll to produce a thin metal strip, a paddle of the molten metal discharged from a nozzle is used. In order to stabilize,
In Japanese Laid-Open Patent Publication No. -141837, it is proposed that a nozzle that supplies molten metal onto a roll that rotates at a high speed is provided with a shield plate that blocks the high-speed air flow that is in tandem with the roll so as not to collide with the air flow. Further, Japanese Patent Application Laid-Open No. 57-159247 proposes to provide a shielding plate that blocks the air flow accumulated on the surface of the cooling roll to minimize the influence on the molten metal flow. In either case, the adverse effect of the external air flow on the discharge flow of the molten metal is suppressed by blocking the external air flow accompanied by the roll in front of the nozzle.

Further, Japanese Patent Application Laid-Open No. 59-209457 discloses a method of supplying a low-density gas to the upstream region of the pouring portion in the vicinity of the quenching region.

[0004]

When the outside air that accompanies the rotation of the chill roll is shielded by the shield plate, the turbulent boundary layer that develops along the chill roll is separated and removed and the turbulent boundary layer develops above the boundary layer. Two effects of blocking the gas flow can be expected.

In particular, when the amorphous ribbon is produced, the gap between the nozzle and the cooling roll is usually 0.5 mm or less, and therefore, the removal of the turbulent boundary layer is important among the above effects. However, when the turbulent boundary layer is separated by the shield plate, the atmospheric pressure in the downstream side area of the shield plate is reduced, and the atmosphere is entrained here, and a new turbulent boundary layer is generated and developed, and as before. When the cooling roll speed exceeds 20 m / s, it is known that the boundary layer has the relationship shown in FIG.

That is, FIG. 1 plots the thickness of a new boundary layer developed after separation on the vertical axis, with the point at which the same air current is separated by a shield plate as the origin of the horizontal axis in the production of a general metal ribbon. From the figure, the boundary layer develops to the extent that it fills the gap between the nozzle and the chill roll about 6.5 mm after peeling, and further 16.5 mm or more, the effect of peeling the boundary layer upstream of the nozzle is complete. It turns out that it disappears.

Therefore, in order to minimize the adverse effect of the air current outside the band on the gap between the nozzle and the cooling roll, it is necessary to install a shielding plate at a position within 16.5 mm from the nozzle. It is difficult to put the shielding plate in the space allowed above.

On the other hand, a method is conceivable in which the air around the nozzle is replaced with a different gas by, for example, blowing a different gas from the outside. Here, according to the same experiment as in FIG. 1 described above, for example, a circumference of 1/4 rotation of a general roll is 400 mm.
In, the thickness of the developing boundary layer is about 2.5 mm.
Therefore, the flow rate of the same air around the nozzle should be 30
With 0 mm,

[Equation 1] 0.0025 mx 20 m / s x 0.3 mx 60 = 0.9 m ³ /
min = 900 l / min will exist.

In order to replace the above-mentioned ambient air with atmospheric gas, 900 l / min of supply gas is required even if the supply gas concentration is secured up to, for example, 50% composition. A supply pipe and a suction port equivalent to 30 to 40 A are required, and it is extremely difficult to install the supply pipe around the nozzle, which has many restrictions.

Therefore, an object of the present invention is to provide an apparatus for producing a metal ribbon which can advantageously achieve blocking of an external air flow that accompanies a cooling roll.

[0011]

In order to solve the above-mentioned problems, the present invention first installs a shielding plate to shut off the boundary layer and the flow of outside air generated above the boundary layer, and also to shield the shielding plate. And by supplying a predetermined gas between the nozzles, the atmospheric pressure in the downstream side region of the barrier plate is made equal to or higher than the atmospheric pressure, decompression here is avoided, and the outside air is prevented from flowing into the downstream side region of the barrier plate. is there.

That is, according to the present invention, in a metal ribbon manufacturing apparatus having a cooling roll that rotates at a high speed and a nozzle that guides the discharge of molten metal to the surface of the cooling roll, the molten metal discharge position by the nozzle is upstream in the roll rotation direction. On the side,
A shielding plate extending in the axial direction of the cooling roll with a width of the molten metal film discharged on the surface of the cooling roll is arranged close to the cooling roll surface, and a gas for making the downstream region of the shielding plate an atmospheric pressure of atmospheric pressure or higher. This is a metal ribbon manufacturing apparatus provided with a gas pipe for supplying.

In the present invention, when the gas supplied from the gas pipe has a quality improving effect on the molten metal, the quality of the obtained metal ribbon can be improved. Further, since the outside air flow is separated on the upstream side of the gas supply, the atmosphere is replaced with gas almost completely, and a high-concentration gas atmosphere is obtained.

[0014]

In the device of the present invention, the shielding plate installed on the upstream side of the nozzle is normally attached to the cooling roll, and is usually several hundreds.
It prevents the atmospheric layer of about μm thickness from being caught in the pouring part. On the other hand, due to the installation of the shielding plate, the downstream side region is in a decompressed state, so that a new atmospheric flow is generated here. However, this newly generated atmospheric flow is equal to or higher than the ambient atmospheric pressure by supplying a predetermined gas to the depressurized space in the downstream side area of the shielding plate, and the atmosphere in the downstream side area of the shielding plate is increased. Since the air is replaced with a predetermined gas, the inflow of air into the space is avoided, and the paddle of the pouring section can be stabilized.

Further, the boundary layer unavoidably generated along the cooling roll and the atmosphere above the boundary layer have a predetermined gas composition, which contributes to improving the quality of the obtained ribbon.

The predetermined gas species are CO, CO ₂ , H
e, H ₂ , O ₂ , H ₂ O, etc. are compatible, and all have the effect of stabilizing the molten metal paddle and improving the ribbon quality.
Confirmed by experiments. Further, the gas may be a single component or a plurality of mixed components.

[0017]

FIG. 2 shows an apparatus for producing a metal ribbon according to the present invention. In the figure, reference numeral 1 is a melting furnace, and this melting furnace 1
The molten metal 2 heated and held in the tundish 3 is supplied into the tundish 3, and the molten metal 2 is discharged from the nozzle 4 installed at the end of the tundish 3 onto the cooling roll 5 rotating at high speed. The ribbon 2 is rapidly solidified on the cooling roll 5 to form the ribbon 6. The obtained ribbon 6 is wound on the winding reel 7.

A holder 9 fixed to the nozzle 4 is provided with a shield plate 8 extending in the roll axial direction at a length equal to or larger than the width of the molten metal film discharged on the surface of the cooling roll 5, on the upstream side of the nozzle 4 in the roll rotation direction. Through the CO, and placed on the surface of the cooling roll without any gap, and CO, C
A gas pipe 10 for supplying a predetermined gas such as O ₂ or He is provided.

Next, using the apparatus shown in FIG. 2,
The production of the metal ribbon will be specifically described. That is,
In a melting furnace 1, a steel ingot containing Fe: 80 wt% and Si: 15 wt% as main components was heated and held in a molten state for 5 tons, the molten metal was supplied into the tundish 3, and the tundish 3 was set to have an opening width. : Rotate molten metal at high speed from 400 mm nozzle 4 (30 m
/ S) was discharged onto the peripheral surface of a copper alloy cooling roll 5 (axial length: 600 mm) to produce a thin strip 6. Where the nozzle 4
The gap between the roll and the roll 5 was 150 μm. Also, the shielding plate 8
The distance between the nozzle and the nozzle was set to 20 mm, 50 mm, and 100 mm, and the shield plate 8 was structured to contact the roll when the gap between the nozzle and the roll was 150 μm. Further, as the gas pipe 10, a pipe having an outer diameter of 4 mm is inserted between the shielding plate 8 and the nozzle 4 at a pitch of 50 mm, and various gases are supplied at a rate of 100 to 100 m per unit width of the ribbon.
2000l / min range, for example, 30 to 60l when converted to 300 mm width
/ Min.

For each level showing the implementation conditions in Table 1, 5t
Was cast 5 times each, and about 10 m of the thin strip obtained at the time of the 2.5 t casting, the strip was cut into 100 mm lengths, and the surface roughness of the cut plate was measured. This surface roughness is an index showing how many windings can be made in a unit winding thickness when a thin strip is laminated, for example, like a roll, and is a quality index showing performance when used for a motor iron core. .

As a comparison, the same experiment was performed and evaluated in the same manner with and without the shield plate. The respective evaluation results are also shown in Table 1.

[0022]

[Table 1]

[0023]

According to the structure of the device of the present invention, the shielding plate shields the outside air that accompanies the roll on the upstream side of the nozzle, and the specific gas can be supplied to the downstream side of the shielding plate. Both the effect and the sealing effect by the specific gas can be exhibited, and the ribbon quality, especially the surface roughness can be greatly improved. In addition, the effect of the shielding plate can reduce the amount of gas hitting the nozzles, cooling of the nozzles can be prevented, and nozzle clogging can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a distance between a cooling roll and a nozzle and a boundary layer thickness.

FIG. 2 is a schematic diagram showing an apparatus of the present invention.

[Explanation of symbols]

 1 Melting furnace 2 Molten metal 3 Tundish 4 Nozzle 5 Cooling roll 6 Thin strip 7 Winding reel 8 Shielding plate 9 Holder 10 Gas pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Shibuya 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Co., Ltd. Chiba Works (72) Inventor Katsumi Kurokawa Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Works Co., Ltd. Chiba Steel Works (72) Inventor Toru Sato 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Works Chiba Works (72) Satoshi Suhara, 1 Kawasaki-cho, Chuo-ku, Chiba City Kawasaki Steel Works Co., Ltd. Chiba Steel Works (72) Inventor Kenji Nakagawa 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Works Chiba Works

Claims (1)

[Claims] 1. A metal ribbon manufacturing apparatus having a cooling roll rotating at a high speed and a nozzle for guiding the discharge of molten metal to the surface of the cooling roll, wherein a cooling is provided on the upstream side in the roll rotation direction of the molten metal discharge position by the nozzle. A shield plate extending in the axial direction of the cooling roll with a width equal to or larger than the width of the molten metal film discharged onto the roll surface is disposed substantially close to the cooling roll surface, and the downstream region of the shield plate has an atmospheric pressure of atmospheric pressure or higher. An apparatus for producing a metal ribbon, which is provided with a gas pipe for supplying the gas of