JPS5861953A - Method and device for producing quickly cooled thin metallic strip - Google Patents

Abstract

PURPOSE:To prevent the roughening of the surfaces of rotary rolls which solidify molten metal quickly to a thin strip and to produce the thin strip having smooth surface characteristics by spraying a lubricating oil and fine powder of an inorg. material successively on the rotating surfaces of said rolls on the upper stream of the revolutions of said rolls. CONSTITUTION:The molten metal 2 from a nozzle 1 is cooled quickly on rolls 4, 5, to form a thin strip 3. Electrostatic powder painting guns 6, 7 are disposed on the upper stream side of the revolutions of the rotating and cooling surfaces of the cooling rolls 4, 5, and further oil mist nozzles 8, 9 are disposed on the upper stream side of the revolutions thereof. A lubricating oil, for example, rapeseed oil, is sprayed from the nozzles 8, 9 onto the cooling surfaces of the rolls 4, 5 to form the lubricating oil films. Fine powder of an inorg. material having good heat conductivity, for example, graphite,is prayed from the guns 6, 7 by the electrostatic fields of the rolls 4, 5 and the guns 6, 7, whereby the thin films wherein the lubricating oil and the fine powder are mixed uniformly are formed on the cooling surfaces of the rolls 4, 5, and the metal 2 is made into the strip 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rapidly cooled metal ribbon and an apparatus for producing the same. The present invention relates to a method for producing a rapidly solidified metal ribbon with a smooth surface and an apparatus for producing the same.

A method is known in which molten metal is injected from a nozzle onto the rotating cooling surface of a cooling roll, rapidly cooled, and solidified to produce an amorphous or microcrystalline quenched ribbon.

However, according to the above method, the rotating cooling surface of the cooling roll becomes rough due to the temperature rise caused by the molten metal, and the surface of the rolls also becomes rough due to mutual rolling blades. When the ribbon is manufactured, there is a drawback that the surface of the manufactured ribbon is not smooth.

In order to eliminate the above-mentioned drawbacks, a method has been proposed in which a lubricant is applied to the surface of the roll and then molten metal is jetted, rapidly cooled, and solidified.

The present applicant has disclosed a method of applying a mixture of lubricating oil and a fine powder with good thermal conductivity, such as a mixture of rapeseed oil and graphite, using a coating roll or a spray gun in Japanese Patent Application No. No. 19 of JA-/-T developed a method for electrostatically coating fine powder with good thermal conductivity, such as graphite, and filed an application.

However, with the former method, it is difficult to uniformly mix the lubricating oil and the fine powder with good thermal conductivity, resulting in an uneven coating film on the rotating cooling surface, and with the latter method, the fine powder is mixed negatively. The coating is applied by applying a high voltage of 30 to 50KV between the coating gun and the roll, but the charge is not lost immediately after it adheres to the fine powder/kiln, and the adhesion force decreases, and the centrifugal force of the roll causes it to be coated. There was a drawback that the powder was scattered.

The present inventors have eliminated the drawbacks of the conventional method as well as the above-mentioned method previously applied by the present applicant.

It is an object to provide an improved method and apparatus, and this object can be achieved by providing the method and apparatus as set forth in the claims.

The invention will now be explained with reference to the figures.

The figure is an explanatory longitudinal cross-sectional view of the apparatus of the present invention for producing a rapidly solidified metal ribbon using a twin-pole. Molten gold Ji4 from nozzle l
J to double p-ruda,! When the molten metal is injected near the contact line of Further, an oil mist nozzle is disposed on the rotationally upstream side. Oil mist nozzle tI? When a lubricating oil, such as rapeseed oil, is injected onto the rotating cooling surface of the four wheels, a lubricating oil film is formed. Fine inorganic powder with good thermal conductivity, such as fine graphite powder, ejected from an electrostatic powder coating gun 6et is negatively charged and then applied to a cooling rollder.

! When a high voltage of 30 to 90 KV is applied between the paint gun 6 and the coating gun 6, and the electrostatic field is used to spray the powder onto the rotating cooling surface of the roll, the lubricating oil and the fine powder on the rotating cooling surface of the roll are uniformly distributed. A mixed thin film is formed on the rotating cooling surface of the roll, and molten metal is ejected from a jet nozzle onto the rotating cooling surface covered by the formed thin film to produce a quenched metal ribbon.

According to the present invention, unlike the method previously filed by the applicant, the mixing ratio of the lubricating oil and the fine powder is controlled by separately spraying and coating the lubricating oil and the fine powder onto the rotating cooling surface. can be changed easily and accurately,
It has also become possible to form a uniform thin film of am oil and fine powder on the rotating cooling surface.

According to the present invention, by arranging the oil miss F gun Itde on the upstream side of the roll rotation than the electrostatic powder coating gun 6.7, the lubricating oil is applied to the rotating cooling surface of the roll before the powder is applied. Because the lubricating oil has electrical insulation and adhesive properties, the fine powder that later adheres to the rotating cooling surface of the rotor does not lose its negative charge and remains electrostatically attracted. At the same time, the adhesive force of the lubricating oil is added to the fine powder, which can sufficiently counteract the force that tries to separate the fine powder from the roll surface due to the centrifugal force of the roller, so the fine powder sticks to the roll surface. The attached state can be maintained.

Next, the present invention will be explained using experimental data.

Roll surface is hard chrome plated, diameter WOO■φ3
Using a set of twin rolls whose cooling surfaces were each coated with one of the following three conditions, the rolling reduction of the rolls was performed at a rolling speed of 1 s/! 11/B. .

6.3% 5i-F molten metal 10189 was continuously jetted from the nozzle near the contact line of each twin roll and rapidly cooled.

By coagulating, thin strips each having a thickness of 100/Jm and a width of 5011IsL were produced, and the roughness of the roll surface was compared.

■ Rapeseed oil + graphite mixture Mist spray application Rapeseed oil viscosity 30c/day Graphite average particle size 5μm Mixing ratio (volume) Rapeseed oil: Gra7ite? :l Spraying is done using air pressure! '9/C112 ■ Graphite electrostatic coating Graphite average particle l Particle size: 70 μm Electric field voltage: D OjtOKV Spraying is performed using air pressure 19/cs2 After completing the above experiment, the maximum surface roughness of the rotating cooling surface of each of the three sets of twin rolls was measured, and the results were as shown in the table below. There was. Also ■.

■ is based on the method previously filed by the applicant, and ■
is based on the method of the present invention.

That is, it can be seen that the method of the present invention significantly reduces roughening of the roll surface.

Although the above experimental data are the results when twin rolls were used, similar results were obtained when a single roll was used.

The lubricating oil used in the present invention has adhesive strength that will not scatter due to centrifugal force when sprayed onto the rotating cooling surface of the roll from an oil mist nozzle, a viscosity that will form a film of uniform thickness, and electrical insulation properties. For example, rapeseed oil, linseed oil, etc. can be advantageously used.

The inorganic fine powder with good thermal conductivity used in the present invention is graphite e Fe2O3t SiOt Tic
Inorganic fine powders having good thermal conductivity and a certain degree of heat resistance, such as eCoo lMgO* ZrO2y TiO2, can be advantageously used.

Next, the present invention will be explained with reference to examples.

Example Using rapeseed oil as the lubricating oil and graphite as the fine powder, the oil mist air pressure was 4'& 9/ClI2 and the fine powder was sprayed at a pressure of 4' kg/cs + 2 m.The voltage between the two rolls of the electrostatic powder coating gun was set to DC. At 60 KV, there is a lubricating oil film j pm on the rotating cooling surface of the twin rolls, and μ on the fine powder film.
It was possible to obtain a lubricating thin film with a uniform number of 7 m.

Konoyo Una I4? #When a 6.3% 5i-1i' molten metal was jetted from a nozzle near the contact line of the twin rolls on which a thin film was formed and rapidly solidified, a microcrystalline silicon fIIi ribbon with an extremely smooth surface could be obtained. Furthermore, compared to the conventional method, the roughening of the rotating cooling surface of the roll is extremely small, and the useful life of the roll is significantly improved.

As described above, according to the present invention, it is possible to produce a ribbon with an extremely smooth surface, and the roughening of the rotating cooling surface of the cooling roll used for this production is reduced, making it possible to produce a quenched metal ribbon extremely advantageously. Can be done.

[Brief explanation of the drawing]

The figure is an explanatory longitudinal cross-sectional view of an apparatus directly used to carry out the method of the invention. /... nozzle, c... molten metal, 3... quenched metal ribbon, da, 5... roll, 6. ri...painting gun, V
*9...Oil mist nozzle. Patent applicant: Kawasaki Steel Corporation

Claims (1)

[Claims] 1. A method for producing a quenched metal ribbon in which molten metal is jetted from a nozzle onto the rotating cooling surface of a roll, quenched, and solidified,
The rotation is achieved by injecting lubricating oil onto the rotating cooling surface from an oil mist nozzle disposed opposite to the rotating cooling surface on the rotationally upstream side of the portion where molten metal is sprayed onto the rotating cooling surface of the roll. A lubricating oil film is formed on the cooling surface, and the oil mist nozzle is disposed on the rotational upstream side of a portion where molten metal is injected onto the rotating cooling surface of the roll, and facing the rotating cooling surface. An electrostatic powder coating gun disposed opposite the rotating cooling surface on the rotational downstream side of the rotating cooling surface position where the electrostatic powder coating gun applies inorganic fine powder with good thermal conductivity to the rotating cooling surface facing the electrostatic powder coating gun. The molten metal is sprayed onto the upper lubricating oil film and electrostatically coated to form a uniformly mixed thin film of the lubricating oil and fine powder, and the molten metal is jetted from a nozzle onto the rotating cooling surface of the roll on which the uniformly mixed thin film is formed. A method for producing a rapidly cooled metal ribbon having a smooth surface while preventing roughening of the rotating cooling surface of a roll, characterized by rapid cooling and solidification. 2. Production of a quenched metal ribbon, which has a spouting nozzle and a roll having a rotating cooling surface facing the nozzle, and spouting molten metal from the spouting nozzle onto the rotating cooling surface of the roll to rapidly cool and solidify it. In the apparatus, an oil mist nozzle is provided facing the rotary cooling surface on a rotationally upstream side of a rotary cooling surface portion that the jet nozzle faces; and an electrostatic powder coating gun disposed opposite the rotary cooling surface on the rotational downstream side of the rotary cooling surface portion where the oil mist nozzle is disposed facing the rotary cooling surface. In this apparatus, lubricating oil is sprayed from the oil mist nozzle onto the opposing rotating cooling surface, and inorganic fine powder with good thermal conductivity is sprayed from the electrostatic powder coating gun onto the opposing rotating cooling surface. The molten metal is jetted from a jet nozzle onto the rotary cooling surface, which is electrostatically coated to form a uniformly mixed thin film of the lubricating oil and the fine powder, and is rapidly cooled and solidified. An apparatus for producing quenched metal ribbon having a smooth surface while preventing roughening of the rotary cooling surface of a spinning wheel.