JPH03114636A - Manufacture of rapidly cooled metallic thin strip - Google Patents

Abstract

PURPOSE:To perfectly detach the metallic strip from the roll and to stably manufacture the metallic strip of long size by using the gas knife of the specific gas for detaching off the metallic strip from the roll in the case of manufacturing the amorphous metallic strip by injecting the molten metal on the single roll of high speed revolution. CONSTITUTION:The molten metal in the tundish 7 is injected from the molten metal injecting nozzle 1 on the cooling roll 2 which rotates at a high speed, is super-rapidly cooled on the roll 2 and is formed to the amorphous metallic thin belt 3 and then is detached from the cooling roll 2 with the gas knife and is formed to the path-line at the position of the deflector roll 5 and the amorphous metallic thin belt 6 which is detached off from the cooling roll 2 is held with the pinch roll 9 and wound up. In this case, by using, as the injecting gas from the gas knife 4, the gas having <=0 deg.C dew point or the gas which is mixed with 0.001weight% of the oil, or the gas having the above both conditions, the amorphous metallic thin belt 6 is easily detached from the cooling roll 2 and the amorphous metallic thin belt of excellent surface property is stably manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a manufacturing method for continuously and stably manufacturing a quenched metal ribbon such as an amorphous metal ribbon by a single roll method.

[Prior art 1] In recent years, the development of manufacturing technology for directly processing molten metal (including alloys; the same applies hereinafter) into metal ribbons has been progressing by liquid quenching methods such as the single roll method and the twin roll method. The first important elemental technology in these direct plate manufacturing technologies is the plate making technology itself related to plate thickness uniformity and surface texture, but when considering industrial production, there are equally important technologies. Therefore, it is important to establish a winding technology to wind it into a coil.

When making an amorphous alloy ribbon using the single roll method, the molten metal injected from the pouring nozzle is ultra-rapidly solidified on the surface of a cooling roll rotating at high speed, becoming an amorphous alloy ribbon, and the cooling roll It sticks to the surface and rotates with the roll. Therefore, unless there is some means to separate it from the cooling roll, the amorphous alloy ribbon wrapped around the cooling roll surface will collide with the pouring nozzle after making one rotation.
If it is too large, the ceramic nozzle will be damaged.

In order to avoid such troubles, a gas knife such as air or nitrogen is installed on the circumference of the cooling roll at a position half a turn to 3/4 turn downstream from the pouring nozzle, and a gas knife of air or nitrogen is installed on the circumference of the cooling roll to cool the amorphous alloy ribbon. Conventionally, peeling from the surface has been carried out.

Until now, no particular attention has been paid to the type and properties of the gas used in this gas knife. For example, air pressurized by an air compressor is often used as is. When manufacturing a small amount of amorphous alloy ribbon in a laboratory, the type and properties of the gas used in the gas knife have little effect on the sheet manufacturing process, and the difference has hardly been a problem. However, it has been found that when industrial plate making is carried out over a long period of time, the influence of the gas properties of the gas knife on stable plate making operations cannot be ignored.

In other words, the circumferential speed of the cooling roll, the roll material and surface properties,
Even if casting conditions such as the material and tip shape of the pouring nozzle, the temperature and injection pressure of the molten alloy, and the gap between the nozzle and the roll are kept constant, the surface quality of the amorphous alloy ribbon may sometimes deteriorate. Furthermore, in extreme cases, molten metal droplets may fly in front or behind the nozzle, making it impossible to produce stable plates.

[Problem to be Solved by the Invention 1] The present invention was achieved based on operational data obtained through repeated manufacturing experiments and analysis of the casting process in order to solve the instability factors in the prior art. .

When manufacturing a quenched metal ribbon using the single roll method, it has been common practice to peel the quenched metal ribbon using a gas knife. After repeated long-term plate-making experiments on an industrial scale, it was discovered that the plate-making conditions significantly changed depending on the properties of the gas in the gas knife. That is, the surface quality of the amorphous alloy ribbon deteriorates, and in extreme cases, molten metal droplets fly in front or behind the nozzle, making it impossible to achieve stable sheet production.

The purpose of the present invention is to continue the industrially favorable plate manufacturing situation when manufacturing quenched metal ribbons such as amorphous alloy ribbons,
The purpose is to propose suitable gas properties for gas knives that do not impair this.

[Means to solve the problem]

In the present invention, when manufacturing a quenched metal ribbon by injecting molten metal from a pouring nozzle onto the surface of a cooling roll that rotates at high speed and rapidly solidifying it, the quenched metal ribbon that is manufactured in close contact with the cooling roll surface has a dew point This is a method for producing a quenched metal ribbon, characterized in that peeling is performed using a gas knife using gas at 0° C. or lower.

In addition, in this case, good results can be obtained by using a gas knife that uses a gas with a limited amount of oil mixed in to less than o, ooi weight percent, instead of a gas with a dew point of 0°C or less.
Further, it is more preferable to use a gas knife using a gas whose dew point is 0° C. or lower and the amount of oil mixed in is limited to 0.001% by weight or less.

[For further use] In the single roll method in which a quenched metal ribbon is produced in close contact with a cooling roll, the quenched metal ribbon is generally peeled off using a gas knife. This is because mechanical peeling means cannot peel a quenched metal ribbon, which is extremely thin (and has strong adhesion) such as an amorphous alloy ribbon, from the cooling roll.

In the present invention, the reason for focusing on the gas properties of the gas knife was a failure in the drying system of the air compressor.

One day, I was casting without noticing that the drying system of the compressor had malfunctioned, and even though I had been working normally until then, molten metal splashed in front or behind the pouring nozzle. It was not possible to make stable plates.

After investigating various causes, it was discovered that the dew point of the air used for the gas knife was 20°C, and the temperature of the water used to forcibly cool the inside of the cooling roll was 18°C, resulting in dew condensation on the surface of the cooling roll. It was reached. In other words, it was understood that because high-temperature molten metal was poured onto minute water droplets on the surface of the cooling roll, the water droplets vaporized and expanded all at once, scattering droplets of molten metal.

Therefore, in the present invention, molten metal is injected from the tip of the pouring nozzle, collides with the cooling roll surface, and at the same time is ultra-quenched and solidified, and the solidification process into a rapidly cooled metal ribbon is considered from the perspective of deposits on the cooling roll surface. did. In other words, the gas properties of the gas knife are limited so that even if high temperature molten metal comes into contact with the surface of the cooling roll, the molten metal retainer will not be destroyed, and the gas knife will not contaminate the roll surface.

If the melting point and boiling point of the deposit is higher than the temperature of the molten metal (and remains solid when in contact with the molten metal, the heat transfer coefficient between the molten metal and the cooling roll has changed due to the presence of this deposit) However, it is presumed that the effect on the coagulation process is not so great.

When considering the solidification process for quenched metal ribbon, the most dangerous situation is that the molten metal cannot directly contact the surface of the cooling roll, which prevents smooth cooling and solidification. That is, a liquid phase or a gas phase may be present between the molten metal and the roll surface. Especially when inclusions are vaporized by exposure to high temperatures of molten metal,
Since explosive volumetric expansion occurs at the interface between the molten metal and the cooling roll, the pool from the pouring nozzle to the roll surface is completely destroyed, making it impossible to produce a satisfactory quenched metal ribbon. It turns out.

There are several origins of deposits that adhere to the cooling roll surface, but in the present invention, the gas in the gas knife, which is essential in the single roll method, was first investigated in detail from the viewpoint of moisture content, or dew point.

In industrial casting, circulating water is always used to cool the cooling roll from the inside, and the roll surface temperature at the start of casting is almost equal to the temperature of the cooling water. Cooling water is circulated in large quantities and is usually stored in an aquarium, so the temperature of the cooling water changes with seasonal temperature fluctuations, ranging from about 30°C in the summer to about 5°C in the winter, with a difference of 25°C. be. This temperature is directly reflected in the surface temperature of the cooling roll. From the viewpoint of dew condensation on the roll surface, the dew point of the gas in the gas knife should be less than 5°C, but in terms of safety, it is more preferably 0°C or less. In fact, when the dew point of the gas was intentionally set higher than the cooling water temperature (i.e., when the cooling water temperature was 20°C, the dew point of the gas for the gas knife was set to 25°C, condensation occurred on the surface of the cooling roll, and at the same time as pouring A paddle break occurred and stable board production could not be achieved.

In order to make the dew point of the gas for the gas knife 0° C. or lower, specifically, the compressed air can be dehumidified by passing it through an air cooler cooled with a refrigerant.

Next, we investigated the impurities that tend to adhere to the cooling roll surface for compressed gases such as air and nitrogen that are suitable for industrial use, and found that the most likely impurity was oil. This was specifically experienced as contamination from compressors or piping construction. Therefore, when we investigated the upper limit concentration that would not affect the plate-making situation, we found that there would be no problem if the oil content was about 0.001% by weight or less, so this was set as the upper limit concentration in the present invention.

In order to reduce the oil content in the gas to below this concentration, it is insufficient to use only the oil separator used in ordinary compressors, and it is also necessary to use micro mist filters, activated carbon filters, etc.

The type of gas used in the gas knife does not matter as long as it is safe, such as air, nitrogen, or argon.
Air can be advantageously used from the viewpoint of cost and consideration to oxygen deficiency around the equipment.

The amount of knife gas used to reliably peel off a wide amorphous alloy ribbon is 2000 to 250 ON per hour.
It is safe and economically advantageous to use air because it also reaches rrl'.

[Example] The method of the present invention will be specifically explained by taking the production of an amorphous alloy ribbon as an example.

FIG. 1 shows that molten metal injected from a pouring nozzle 1 is ultra-rapidly cooled and solidified on the surface of a cooling roll 2 rotating at high speed, forming an amorphous metal ribbon 3, and then being removed from the cooling roll 2 by a gas knife 4. It shows how it peels off and flies toward a winder (not shown). In the figure, the state of the amorphous metal ribbon 6 when tension is applied by the winder and a pass line is formed at the position of the deflation crawl 5 is also shown by dotted lines.

After supplying the molten alloy having a Fe7BMnl B125 i7 C1 composition (atomic %) maintained at 1300°C into the sufficiently preheated tandy dish 7, the stopper 8 above the pouring nozzle 1 is opened, and the opening slot of the pouring nozzle l is opened. When the molten metal was injected all at once onto the surface of an internal water-cooled copper alloy cooling roll 2 rotating at a high speed of 25 m/s, an amorphous alloy ribbon 3 with a width of 100 mm was produced in close contact with the cooling roll surface. Ta.

Next, after being pressurized by a compressor, it is dehumidified and purified, and is formed by a planar high-speed air flow of air (dew point: 10°C, oil content: 0.0001% by weight), which is controlled at approximately 3 kg/cri'' by a pressure regulating valve. With the gas knife 4,
Peel off the amorphous alloy ribbon 3 that is in close contact with the cooling roll 2 surface,
It flew toward the winder. After catching this flying amorphous alloy ribbon with the pinch roll 9 on the trolley 10,
The trolley 10 was moved to the rear of the winding machine, and was adhered to a winding reel of a winding machine (not shown) that rotates at the same speed as the cooling roll, and winding was started. The winding tension by the winding machine is 2 to 4k.
When controlled to g/crn', a stable pass line was formed and continuous plate making and winding were realized.

After continuing plate making in this state for about 20 minutes, the pouring nozzle 1 was moved away from the cooling roll 2 while using the gas knife 4 to stop casting. As a result, the plate making was completed, and the ribbon at the tail end flew away from the cooling roll 2 by the gas knife 4 without being wound around the cooling roll 2. Therefore, the pouring nozzle 1 was not damaged not only during the plate making but also at the end of the plate making.・During the plate-making process, an extremely stable pool of molten metal was formed at the tip of the pouring nozzle, resulting in smooth casting.

[Effect of the invention 1] According to the present invention, the production of quenched metal ribbons by the single roll method can proceed smoothly, so the effectiveness of the present invention is extremely high when manufacturing quenched metal ribbons industrially. big.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the quenched ribbon solidification process.

Claims (1)

[Claims] 1. A quenched metal thin strip that is produced in close contact with the surface of a cooling roll when molten metal is injected from a pouring nozzle onto the surface of the cooling roll rotating at high speed and rapidly solidified to produce a quenched metal ribbon. A method for producing a rapidly cooled metal ribbon, which comprises peeling the ribbon using a gas knife using a gas having a dew point of 0° C. or lower. 2. Instead of using a gas with a dew point of 0°C or lower, the amount of oil mixed in is 0.
2. The method for producing a quenched metal ribbon according to claim 1, wherein less than 0.001% by weight of the gas is used. 3. The method for producing a quenched metal ribbon according to claim 1, wherein a gas having a dew point of 0° C. or less and an oil content of 0.001% by weight or less is used.