JPH0775855A - Manufacture of metallic strip - Google Patents

Abstract

PURPOSE:To stably manufacture a strip by the single roll method by blowing particles of sand and metal or the like on the surface of a cooling roll, and then, re-activating the surface of the cooling roll by rubbing the roll surface with a rotary brush. CONSTITUTION:Particles of <=2mm in diameter of sand, metal, glass, ceramics or the like are blown on the surface of a cooling roll 1 by a shot blasting device 4, and the layer of the oxide film on the roll surface is removed so as not to remarkably reduce the cooling capacity to re-activate the surface of the cooling roll 1. Then, the surface of the roll 1 is further rubbed with a rotary brush 6 to remove the particles attached by the shot blasting, achieving the stable manufacturing of a strip 3 by the single roll method. The variance in thickness of the produced strip 3 can be reduced, and foregin matters can be prevented from being mixed in the strip 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal ribbon by a single roll method.

[0002]

2. Description of the Related Art An apparatus as shown in FIG. 4 is used for producing a metal ribbon by a single roll method. It has a melting furnace 7 for holding the molten metal 9, a tundish 8 for receiving the molten metal 9 from the melting furnace 7 and eliminating the dynamic pressure, and a nozzle 2 for supplying the molten metal 9 from the tundish 8 and injecting it into the cooling roll 1. . A hole or slit for injecting the molten metal 9 is provided at the tip of the nozzle 2. The molten metal 9 injected onto the roll surface is cooled and becomes a crystalline or amorphous plate 10. The cooling roll 1 is rotating at a high speed, the molten metal 9 is carried away while being held on the roll 1, and separated from the roll surface by a doctor blade, an air knife 11, etc. at a position away from the supply point of the molten metal 9. To be done. After the strip is peeled off, the roll surface returns to the supply point of the molten metal 9 with the rotation and receives the molten metal 9 again.

In the single roll method, the surface of the roll is exposed to the molten metal at a high temperature as described above, so that the surface is extremely oxidized and the oxide is accumulated. Foreign substances other than oxides may adhere. As a conventional method for removing foreign matters and oxides on the roll surface, Japanese Patent Publication No. 61-2
As disclosed in Japanese Patent No. 7145, there is a method in which a strip is peeled from a roll and then brushing is performed to keep a casting surface on a smooth metal layer surface. In fact, it is 4-21628
After the chill roll is brushed as disclosed in Japanese Patent Laid-Open Publication No. 2003-242242, a method of removing oxide scale produced on the roll surface by projecting or spraying particles of sand, metal, glass, ceramics or the like on the chill roll is disclosed. is there.

Regarding the technique disclosed in Japanese Patent Publication No. 61-27145, the oxide formed on the roll surface is not completely removed, as described in Japanese Utility Model Publication No. 4-21628. This oxide causes a reduction in the cooling capacity of the roll, and may cause the quality of the ribbon to be poor due to poor cooling. In addition, there is usually unevenness in the oxide formation thickness, which causes unevenness in the ribbon thickness. On the other hand, the oxide film can be removed to the extent that it does not adversely affect the product by the shot blasting of Japanese Utility Model Publication No. 4-21628. However, after brushing, shot blasting causes some of the sprayed particles to adhere to the surface of the roll and plunge into the pool of molten steel at the top of the roll, and enter the ribbon. Alternatively, there is a problem that holes are generated in the ribbon.

If the plate to be formed is thick, this is not a problem, but in the case of a thin strip having a thickness of 1 mm or less, the place where the small piece is taken in or the place where the hole is formed becomes a non-uniform portion of the thin strip. There is also a problem that cracks are generated in the ribbon, and even if cracks do not occur, stress is generated in the ribbon, which adversely affects the quality of the ribbon. Further, even if the shot blasting particles are completely removed from the roll surface, the roll surface is flawed due to shot blasting and the surface roughness is lowered. The air in this recess enters between the roll surface and the molten steel, and significantly reduces the cooling rate of the molten steel. Even if the oxide film is removed by shot blasting to prevent the cooling failure, the entrained air causes a further significant cooling failure. At this time, there is also a problem that the intake air leaves a mark as an air pocket on the surface side where the plate was in contact with the roll.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to propose a stable method for producing a ribbon by a single roll method.

[0007]

In order to solve the above problems, the present inventors have examined in detail the factors relating to the oxide film of the ribbon. That is, the oxide film that could not be effectively removed by brushing can be removed by shot blasting to the extent that the plate quality is not adversely affected. After the shot blasting, it is possible to remove blown particles and the like remaining on the roll surface by brushing. However, although the oxide film is removed by shot blasting, the roll surface becomes uneven. The recessed portion causes air to be taken into the molten steel, resulting in poor cooling. It is known that the air entrapped at this time leaves a mark as an air pocket on the surface side where the plate was in contact with the roll. The amount of air entrapped depends on the shape of the hole, but depends largely on the depth of the hole. If the depth of the holes is 10 μm or less, the air is not taken in, which is not perfect but causes significant cooling failure in the plate. At depths of 10 μm or more, cooling failure frequently occurs. It is necessary to control the depth of the irregularities on the roll surface to 10 μm or less. First, the effect of reducing the depth is to reduce the diameter of the sprayed particles and to reduce the spraying pressure, that is, the energy of the particles. In addition, the relationship between the hardness of the roll surface and the hardness of the particles also affects, but the effect of energy is greater. The energy of particles is 1/2 mv ² = πρ
/ 12D ³ v ² . (M: particle mass,
v: collision velocity of particles with rolls, π: circular constant, ρ: particle density, D: particle diameter) The smaller D, the larger v, D
Becomes larger and v becomes smaller and becomes 0. Since the particles are blown out together with the compressed air, v is influenced by the blowing pressure P or the blowing gas amount w in addition to D, and both increase. The hardness and diameter of the particles to be sprayed can be determined by the roll surface hardness, and the roll surface roughness after treatment can be determined. As an example, when the copper roll is used as the cooling roll and the quartz particles are used as the spray particles, the relationship between the spray pressure and the particles and the surface roughness R _max is shown in FIG. If the diameter is 2 mm or less, R _max can be controlled to 10 μm or less.

After the plate making, the surface roughness of the roll is measured,
When R _max is 10 μm or more, the energy of the sprayed particles can be reduced by reducing the spray pressure / gas amount, and R _max can be controlled to 10 μm or less. If defective removal of the oxide film occurs, the number of sprayed particles is increased to deal with it. That is, the present invention is to inject a molten metal through a slit provided in a nozzle on the surface of a cooling roll that rotates at a high speed, rapidly solidify to form a metal ribbon, and peel the metal ribbon from the cooling roll to remove the metal ribbon. In the method for producing, characterized in that the surface of the cooling roll is sprayed with particles of sand, metal, glass, ceramics, etc., and then the surface of the cooling roll is reactivated by rubbing on the surface of the roll with a rotating brush. Metal ribbon production method, and the present invention, after the brush treatment in the above method, to measure the roll surface roughness before molten steel metal injection, the diameter of the sprayed particles, spraying amount, spraying speed by the result It is a method for producing a metal ribbon, which comprises adjusting and controlling the surface roughness of a roll.

[0009]

According to the method of the present invention, as shown in FIG. 1, the shot blasting device 4 is provided with particles having a diameter of 2 mm or less such as sand, metal, glass and ceramics on the surface of the cooling roll.
To remove the oxide film layer on the surface of the roll to such an extent that the cooling ability does not significantly decrease, reactivate the surface of the cooling roll, and then rub the surface of the roll further with the rotating brush 6, and then by shot blasting as described above. By removing the adhered particles, stable production of the ribbon by the single roll method can be achieved.

Even when sprayed particles having a diameter of 2 mm or more are used, the surface roughness of the roll is measured, and when the surface roughness increases, the sprayed particle diameter is reduced, and the spraying pressure and spraying are used. Reduce the amount of compressed air sprayed, increase or decrease the density of particles sprayed,
By reducing the surface roughness, stable production of ribbons by the single roll method can be achieved.

[0011]

[Examples] Examples will be described. Fe: 80%,
After holding a molten alloy having a composition (atomic%) of B: 10%, Si: 9%, and C: 1% at 1300 ° C., it is made of a copper alloy that rotates at a high speed (25 m / sec) from a slit nozzle having a width of 150 mm. Shot directly above the cooling roll, shot blasting sprayed quartz particles with a diameter of 0.5 to 1 mm onto the roll with an air flow of about 35 Nl / sec per roll surface unit area,
While brushing, a metal ribbon having a plate thickness of 25 μm was prepared. FIG. 2 shows, as an example, a length ratio of a cracked portion of a thin strip manufactured by this method. As a comparative example, a case where brushing is performed before shot blasting is shown. The probability of cracking is smaller when brushing is performed after shot blasting.

[0012]

According to the present invention, it is possible to reduce the variation in the thickness of the product ribbon, and it is possible to prevent foreign matter from entering the ribbon.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a casting time and a crack generation length ratio in Examples and Comparative Examples.

FIG. 3 is a characteristic diagram showing the relationship between the amount of air blown gas and R _max depending on the particle size.

FIG. 4 is an explanatory view of a conventional method for producing a metal ribbon by a single roll method.

[Explanation of symbols]

 1 Cooling Roll 2 Nozzle 3 Thin Band 4 Shot Blasting Device 5 Suction Blower 6 Brush 7 Furnace 8 Tundish 9 Molten Metal 10 Crystal or Amorphous Plate 11 Air Knife / Doctor Blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Moriwaki 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside the Chiba Works, Kawasaki Steel Co., Ltd. (72) Katsumi Kurokawa 1 Kawasaki-cho, Chuo-ku, Chiba Prefecture Kawasaki Steel Works Co., Ltd. Chiba Steel Works (72) Inventor Haruhiko Ishizuka 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Works Chiba Works

Claims (2)

[Claims] 1. A metal ribbon by injecting a molten metal through a slit formed in a nozzle onto a surface of a cooling roll that rotates at a high speed, rapidly solidifying the molten metal into a metal ribbon, and peeling the ribbon from the cooling roll. In the method for producing, characterized in that the surface of the cooling roll is sprayed with particles of sand, metal, glass, ceramics, etc., and then the surface of the cooling roll is reactivated by rubbing on the surface of the roll with a rotating brush. Metal ribbon manufacturing method. 2. The surface roughness of the roll after the brush treatment and before the molten steel metal injection is measured, and the result shows the diameter of the sprayed particles,
The method for producing a metal ribbon according to claim 1, wherein the surface roughness of the roll is controlled by adjusting the spraying amount and the spraying speed.