JPS63119957A - Manufacture of rapid cooling metal thin strip and its device - Google Patents

Abstract

PURPOSE:To prevent the generation of a paddle rake and to obtain a thick metal thin strip by tilting backward the flow path of the molten metal flowing out from the slit like orifice located at an upper stream side for the vertical face including the rotary shaft of a roll. CONSTITUTION:The flow path in parallel to the vertical face including the rotary shaft of a cooling roll 2 is formed by a slit like orifice 3 at a downstream side, on the other hand the flow path tilting backward at the angle thetafor the vertical face is formed by a slit like orifice 4 at an upper stream side. The backward tilting angle theta of the upper stream side slit like orifice 4 is regulated in the range of 5-70 deg.. The rapid cooling thin strip which is thick and of good surface state is stably obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a rapidly solidified metal thin strip which is advantageous for producing a crystalline or amorphous metal thin strip directly from a molten metal by rapidly cooling and solidifying the molten metal. The present invention relates to a method for manufacturing a band and a manufacturing device suitable for carrying out the method.

(Prior Art) In recent years, molten metal (including molten alloy) has been used as a method for continuously manufacturing crystalline or amorphous metal ribbons.

A number of so-called quenched ribbon methods have been proposed, in which a continuous ribbon is directly produced by rapidly solidifying (the same applies hereinafter) on the surface of a cooling body. Especially when making an amorphous alloy ribbon, the required 1
A cooling rate of about 04 to 106 °C/S can be easily obtained,
Furthermore, since it is easy to operate and handle, the single roll method is often used, and continuous metal ribbons having a thickness of about 0.02 to 0.05 aua are manufactured by this method.

A typical method for producing an amorphous metal ribbon using a single roll method is, for example, the method disclosed in Japanese Patent Application Laid-open No. 53525/1983. In this manufacturing method, the slit-shaped orifice of the pouring nozzle is
The nozzle is arranged at a nearly right angle, and the distance between the nozzle bottom and the cooling body surface is set to 0.03 to 1 man.

By the way, in general, in the single roll method, the molten metal that is pressurized and injected from the slit is not only drawn out in the rotational direction of the cooling roll, but also flies in the opposite direction to the rotational direction of the roll, causing paddle break. It had the disadvantage of being easy. Needless to say, the blown molten metal not only significantly impairs workability, but also causes a significant decrease in yield since it does not participate in the formation of the quenched metal ribbon.

In this regard, in the above-mentioned Japanese Patent Application Laid-open No. 53-53525, in order to draw out the molten metal flow more easily in the rotational direction of the roll, the edge of the slit of the pouring nozzle on the upstream side when viewed from the rotational direction of the roll is When the slit edge on the downstream side is defined as the first lip and the slit edge on the downstream side as the second lip, the distance between the second lip and the cooling body surface is set larger than the distance between the first lip and the cooling body surface, and the paddle break is performed. We are trying to prevent this from happening.

However, this manufacturing method has a drawback in that the thickness of the obtained ribbon is only about 50 μm at most, especially in the case of Fe-based amorphous alloys.

On the other hand, JP-A-55-18582 proposes a method for manufacturing amorphous metal using a nozzle container having multiple slit-shaped nozzle openings in order to obtain a thick amorphous alloy ribbon. has been done. This method uses a nozzle with multiple openings arranged in parallel in the direction of movement of the cooling body.
The aim is to obtain an amorphous alloy ribbon of 100 μm to 150 μm.

Furthermore, JP-A-60-108144 and JP-A No. 60-1995
53 publications, a plurality of slit openings are provided at the tip of a pouring nozzle, molten metal is injected onto the surface of a cooling roll rotating at high speed, and the ribbon formed from the upstream slit is in an unsolidified state. We have developed a manufacturing method in which molten metal is injected onto the free surface side from a slit downstream, and the unsolidified ribbon is pressed against a cooling roll by the pressure of the molten metal, improving heat transfer and producing a thick metal ribbon. It is reported that an amorphous alloy ribbon having a thickness of nearly 70 μm can be produced by this method.

(Problems to be Solved by the Invention) Although it has become possible to produce a thin ribbon with a larger thickness by the conventional method listed above, the following problems still remain.

In other words, the poured metal flows from multiple openings merge at the paddle, and the metal is poured from a narrower slit, so the injection pressure needs to be set higher than in the single-slit method. When the injection pressure was increased, the pouring metal flow injected from the slit located on the most upstream side flew to the rear of the nozzle, further increasing the tendency for paddle breaks to occur frequently.

Therefore, in the multiple slit system, ensuring the stability of the paddle and suppressing this paddle break remained extremely important issues.

The present invention advantageously solves the above-mentioned problems, and provides a method for producing a quenched metal ribbon that can effectively obtain a thick metal ribbon without causing paddle break. The purpose is to propose this method along with suitable manufacturing equipment for direct use.

(Means for Solving the Problems) That is, the present invention allows molten metal to flow out from a pouring nozzle having a plurality of slit-like openings onto the outer circumferential surface of a cooling roll that rotates at high speed around a horizontal axis, and rapidly cools the metal. When producing a metal ribbon directly from molten metal by solidification, at least the most upstream slit-shaped opening of the plurality of slit-shaped openings is placed against a vertical plane that includes the rotation axis of the cooling roll that rotates at high speed. Molten metal is injected through a nozzle channel that tilts backwards, and the molten metal formed between the nozzle and the roll is an unsolidified puddle.
This is a method for producing a rapidly solidified metal ribbon, which comprises sequentially merging pouring flows from slit-shaped openings located downstream.

The present invention also provides a cooling roll that receives a falling flow of molten metal and forces the metal to rapidly solidify into a thin ribbon, and a pouring nozzle that is provided with a plurality of slit-like orifices on the outer peripheral surface of the cooling roll that supplies the molten metal. The pouring nozzle is arranged almost directly above the center of the roll of the cooling roll, and at least the most upstream slit-shaped orifice of the plurality of slit-shaped orifices of the pouring nozzle is aligned with the rotation axis of the cooling roll. 5 for the vertical plane containing
This is an apparatus for producing quenched metal ribbon, which is tilted backward at an angle in the range of ~70°.

This invention will be specifically explained below.

First, the experimental results that led to this invention will be explained.

The position of the pouring nozzle with two slit-shaped openings is
After conducting various studies to suppress the scattering of molten metal toward the rear of the nozzle, that is, paddle break, in a configuration installed almost directly above the center of the cooling roll rotating at high speed, we found that a slit located on the upstream side as shown in Figure 1 was used. By tilting the flow path of the molten metal flowing out from the shaped orifice backwards with respect to the vertical plane containing the axis of rotation of the rolls, the intended purpose was very advantageously achieved.

In FIG. 1, number 1 is a pouring nozzle 2 is a cooling roll, 3 is a slit-shaped orifice on the downstream side, which forms a flow path parallel to the vertical plane including the rotation axis of the cooling roll 20, and 4 is on the upstream side. The slit-like orifice forms a flow path that is inclined backward at an angle θ with respect to the vertical plane. 5 is the padnope and 6 is the obtained quenched metal ribbon. Here,
If the backward inclination angle θ of the upstream slit-shaped orifice 4 is smaller than 5°, the effect of preventing paddle break will be poor, whereas if it is inclined more than 70°, paddle break will not occur, but air entrainment at the rear surface of the paddle will occur. As a result, the surface roughness on the roll surface side of the obtained ribbon increases, and the average roughness Ra of the ribbon surface is 1.0 μm, which is acceptable as a product.
Therefore, it is important to limit the backward inclination angle θ of the upstream slit-shaped orifice 4 to a range of 5 to 70°.

In addition, in the case of a single backward-tilting slit system without the downstream slit-shaped orifice 3, it is difficult to completely prevent air entrainment from the rear surface of the paddle, especially when the backward tilt angle is 60 to 7.
At 0°, the surface roughness of the roll surface side of the ribbon is 1.0 in Ra.
It was not possible to make it less than μ. On the other hand, the great advantage of the present invention is that the surface roughness on the roll side can be reduced and a smooth ribbon can be produced.

Figure 2 shows that Fe7aB+oSl 12 composition (at leopard) alloy molten metal is passed through a two-slit nozzle made of fused silica at a circumferential speed of 3.
On the surface of a cooling roll made of prepared alloy that rotates at a high speed of 5 m/s, the upstream flow channel is supplied with various backward inclination angles θ,
The results of investigating the manufacturing situation when manufacturing an amorphous metal ribbon by rapid solidification are shown in relation to the backward inclination angle θ of the upstream slit-shaped orifice.Other experimental conditions are as follows: - Distance between lip tip and cooling roll surface: 0.25mm.

・Slit-shaped opening shape: 0.4 mmxlOmm,・
Distance between both slit orifices at the nozzle tip: 2m
m.

The thickness of the first-ranked metal ribbon was 65 to 70 μm.

As is clear from Figure 2, when the occipital angle θ of the upstream slit-shaped orifice was made smaller than 5'' and brought closer to vertical, the frequency of occurrence of paddle breaks suddenly and sharply increased. Accordingly, some unevenness occurred on the ribbon roll surface side due to air entrainment at the rear surface of the paddle, but in the case of the two-slit method as shown in Figure 1, this effect was not as great as in the case of the single-slit method. It wasn't big.

(Function) The reason why a thick quenched ribbon with good surface quality can be stably obtained by tilting the slit-shaped orifice on the upstream side in accordance with the present invention is considered to be as follows.

In other words, when pouring metal using the method described above, the entire paddle is strongly pressed against the cooling roll surface by the downstream eddy current, which significantly increases the heat transfer coefficient between the cooling roll and the molten metal. Since the cooling rate increases accordingly, the thickness of the obtained amorphous alloy ribbon also increases compared to the usual single-slit method.

For example, when manufacturing Fe-based amorphous alloy ribbon continuously using the normal single-slit method, the thickness of the sheet is usually 20 to 40 μm.
However, according to the present invention, an amorphous alloy ribbon of 50 to 90 μm could be produced without occurrence of paddle breaks or the like.

Further, in this invention, since the paddle suppressing effect is exerted by the downstream vortex flow, air entrainment at the rear surface of the paddle is also effectively suppressed.

By the way, in this invention, two or more slit-shaped orifices can be provided at the tip of the pouring nozzle, but in this case,
It is important that the paddles formed on the upstream side sequentially merge the downstream vortices while they are still unsolidified. Otherwise, even if you try to increase the cooling rate by pressing it against a cooling roll, the surface shape of the ribbon has already hardened, so the increase in the heat transfer coefficient will be insufficient, and the amorphous alloy thin film with a thickness of 50 μm or more will It is not possible to make a belt.

For this purpose, the interval between each slit orifice should be 1 to 5.
It is preferable to set it to about ffII11.

A molten alloy having a composition of FetaB+oSl 12 was
When producing an amorphous metal ribbon by continuous supply from a multi-slit nozzle as shown in the figure and rapid solidification on the surface of a cooling roll, the upstream orifice is tilted backwards by 20 degrees, while the downstream orifice is When the orifices were made vertical and the distance between the two orifices was set to 15 mm, the thickness of the metal thin strip was about 66 μm, but it was brittle and crystallized.

Further, the occipital angle of the slit-shaped orifice needs to be gradually reduced toward the downstream side. This is because if the backward inclination angle of the slit orifice on the downstream side is made larger than that of the slit orifice on the upstream side, the effect of improving the surface roughness of the roll surface side of the ribbon deteriorates. The slit-shaped orifice on the most downstream side should be parallel to the vertical plane, or even if it is tilted backwards, the backward tilt angle is 10
It is preferable to set it to about 100°C or less.

Furthermore, the surface roughness of the free surface of the ribbon is largely influenced by the surface roughness of the front lip tip of the downstream flow path, so the lip tip should be smooth and specifically have an average surface roughness Ra of 1.0. μ
It is preferable to set it to about m or less.

Note that if the gap between the nozzle and the roll is too large, holes tend to form in the ribbon, while if it is too narrow, the nozzle tip will wear out, so the above gap should be between 0.1 and 0.1.
It is preferable to set it to about 0.5 mn+.

(Example) Example 1 FetJ+. An amorphous alloy ribbon was produced from a molten alloy having a composition of 5laC+ (at%) in the following manner.

The nozzle was made of silicon nitride, and the cooling roll was made of Cu-Be alloy with internal forced cooling, and the arrangement was as shown in FIG. 1 above under the following conditions.

・Backward tilt angle θ of upstream orifice: 30° ・Occipital angle θ of downstream orifice: 0° ・Distance between nozzle tip and cooling roll surface: 0.3 mm ・Dimensions of upstream slit-shaped opening + 0.5 mm x 50 mm・Dimensions of downstream slit-shaped opening: 0.3 ++t+nX50 mm ・Distance between both orifices: 1 mm ・Circumferential speed of cooling roll: 27 m/s When manufacturing of the rapidly cooled metal ribbon was started under the above conditions,
No paddle break occurred during the manufacturing period, and the plate thickness was 262 mm.
A thick and wide amorphous alloy ribbon with a diameter of .mu.m and good surface quality (Ra: 0.7 .mu.m) was continuously obtained.

Note that the ribbon obtained by X-ray diffraction was confirmed to be amorphous.

Comparative Example 1 When pouring was performed under the same conditions as in Example 1 except that the occipital angle θ of the upstream orifice was 0°, paddle break toward the rear of the nozzle occurred.

Example 2 Si: 0.5 m of molten iron alloy containing 6.5 wt%
Through a pouring nozzle having a slit-shaped orifice with a width of 10 mm x 10 mm, the molten metal was poured onto the surface of a cooling roll made of prepared alloy rotating at a peripheral speed of 40 m/s in the arrangement shown in Figure 1 above under the following conditions. This was then rapidly solidified to produce a crystalline high-silicon steel ribbon.

・Upstream orifice backward tilt angle θ: 50°・Downstream orifice backward tilt angle θ: 0°・Distance between the nozzle tip and the cooling roll surface if! t:0.2
ml/distance between both orifices: 3 nun When the molten metal was poured under the above conditions at a temperature of 1550°C, no puddle break occurred, and the plate thickness: approximately 78 μm, plate width 10 m+, with a beautiful surface without oxidation. We were able to produce silicon steel ribbon.

(Effects of the Invention) As described above, according to the present invention, it is easy to produce quenched metal ribbon with excellent surface quality and large thickness without the disadvantages of reducing yield or destabilizing the puddle due to occurrence of puddle break. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a preferred example of the manufacturing apparatus according to the present invention, and FIG. 2 is a graph showing the relationship between the occipital angle of the upstream slit-shaped orifice and the frequency of occurrence of paddle breaks. ■...Pouring nozzle 2...Cooling roll 3...
Downstream slit orifice 4 Upstream slit orifice 5 Paddle 6 Rapidly cooled metal ribbon Patent applicant Kawasaki Steel Co., Ltd. Figure 1

Claims (1)

[Claims] 1. Molten metal is poured out from a pouring nozzle having a plurality of slit-like openings onto the outer circumferential surface of a cooling roll that rotates at high speed around a horizontal axis, and the molten metal is directly poured out by rapid solidification. When manufacturing a metal ribbon, at least the most upstream slit-shaped opening of the plurality of slit-shaped openings is passed through a nozzle flow path that is tilted backward with respect to a vertical plane that includes the rotation axis of the cooling roll that rotates at high speed. While the molten metal is injected, the molten metal flow from the slit-shaped opening located on the downstream side is sequentially merged while the molten metal formed between the nozzle and the roll by the injected molten metal is not solidified. Features: A method for producing quenched metal ribbon. 2. Consists of a cooling roll that receives the falling flow of molten metal and forces it to rapidly solidify into a thin ribbon, and a pouring nozzle that is equipped with a plurality of slit-shaped orifices that supply the molten metal onto the outer peripheral surface of this cooling roll. , the pouring nozzle is arranged almost directly above the roll center of the cooling roll, and at least the most upstream slit-shaped orifice of the plurality of slit-shaped orifices of the pouring nozzle is arranged in a vertical direction including the rotation axis of the cooling roll. 1. An apparatus for producing a quenched metal ribbon, characterized in that the apparatus is tilted backward at an angle in the range of 5 to 70 degrees with respect to a plane.