JPH0523864B2 - - Google Patents

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. In particular, when making amorphous alloy ribbons, the single roll method is often used because the required cooling rate of about 10 ⁴ to ^{10 6} °C/S can be easily obtained, and it is also easy to operate and handle. , a continuous metal ribbon having a thickness of about 0.02 to 0.05 mm has been produced by this method.

A typical method for manufacturing 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 arranged approximately at right angles to the direction of movement of the cooling surface, and the distance between the bottom of the nozzle and the surface of the cooling body is set to 0.03 to 1 mm.

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 direction of rotation of the cooling roll, but also scatters in the opposite direction to the direction of rotation of the roll, resulting in paddle break. It had the disadvantage of being easy. Needless to say, the scattered 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 as seen from the rotational direction of the roll is 1st lip,
When the slit edge on the downstream side is defined as the second lip, the interval between the second lip and the surface of the cooling body is set larger than the interval between the first lip and the surface of the cooling body to prevent the occurrence of paddle break. It's on.

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

On the other hand, JP-A No. 55-18582 proposes a method for producing 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 a 150μm amorphous alloy ribbon.

Furthermore, in JP-A-60-108144 and JP-A-60-199553, a plurality of slit openings are provided at the tip of the pouring nozzle to inject molten metal onto the surface of a cooling roll rotating at high speed. While the ribbon formed from the slit is in an unsolidified state, molten metal is injected onto the free surface of the ribbon from the downstream slit, and the pressure is used to press the unsolidified ribbon against the cooling roll, thereby transferring heat. A manufacturing method has been proposed that improves the
It has been reported that it is possible to produce an amorphous alloy ribbon with a thickness of nearly 70 μm.

(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 was scattered 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 manufacturing 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 formed on a vertical plane that includes the rotation axis of the cooling roll that rotates at high speed. The molten metal is injected through a nozzle flow path that is tilted backwards, and the molten metal is injected from the slit-shaped opening located downstream while the pool formed between the nozzle and the roll is still unsolidified. This is a method for producing a quenched metal ribbon, which consists of sequentially merging streams of hot metal.

The present invention also provides a cooling roll that receives a falling flow of molten metal and forces the molten metal to rapidly solidify to form a thin ribbon;
A pouring nozzle is provided with a plurality of slit-like orifices for supplying molten metal onto the outer circumferential surface of the cooling roll. At least the most upstream slit-shaped orifice among the plurality of slit-shaped orifices is tilted backward at an angle of 5 to 70 degrees with respect to the vertical plane including the rotation axis of the cooling roll. This is manufacturing equipment.

This invention will be specifically explained below.

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

Various studies were conducted to suppress the scattering of molten metal toward the rear of the nozzle, that is, paddle break, in an arrangement in which a pouring nozzle with two slit-shaped openings was installed almost directly above the center of a cooling roll that rotates at high speed. However, as shown in Figure 1, by tilting the flow path of the molten metal flowing out from the slit-shaped orifice located on the upstream side with respect to the vertical plane containing the rotation axis of the roll, the intended purpose could be achieved. This was achieved very advantageously.

In FIG. 1, number 1 is a pouring nozzle, 2 is a cooling roll, 3 is a downstream slit-shaped orifice, which forms a flow path parallel to the vertical plane containing the rotation axis of the cooling roll 2, and the other 4 is a slit-shaped orifice on the downstream side. The upstream slit-shaped orifice forms a flow path that is inclined backward at an angle θ with respect to the vertical plane. 5 is the paddle, and 6
This is the quenched metal ribbon obtained. Here, if the backward tilt angle θ of the upstream slit-shaped orifice 4 is smaller than 5 degrees, the effect of preventing the occurrence of paddle break will be poor, while if it is tilted more than 70 degrees, paddle break will not occur, but the paddle break will not occur. As air entrainment increases, the surface roughness on the roll side of the resulting ribbon increases, making it impossible to achieve an average roughness Ra of 1.0 μm or less for the ribbon surface, which is acceptable as a product. It is important to limit the backward inclination angle θ of the side 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 at a backward tilt angle of 60 to 70 degrees. It was not possible to reduce the surface roughness of the roll side to less than 1.0μ in terms of Ra. 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 a molten alloy with a composition of Fe ₇₈ B ₁₀ Si ₁₂ (at%) is fed through a two-slit nozzle made of fused silica at a circumferential speed.
When an amorphous metal ribbon is manufactured by rapidly solidifying the upstream flow channel by varying the backward inclination angle θ on the surface of a copper alloy cooling roll rotating at a high speed of 35 m/s, The results of investigating the manufacturing status are shown in relation to the backward tilt angle θ of the upstream slit-shaped orifice.

The other experimental conditions are as follows: Γ Distance between tip of lip and cooling roll surface: 0.25
mm, Γ Slit-shaped opening shape: 0.4 mm x 10 mm, Γ Distance between both slit-shaped orifices at the tip of the nozzle: 2 mm, and the thickness of the obtained metal ribbon was 65 to 70 μm.

As is clear from Fig. 2, when the backward inclination 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 sharply increased. In addition, as the backward tilt angle increases,
Although some unevenness occurred on the ribbon roll surface due to air entrainment at the rear surface of the paddle, in the case of the two-slit method as shown in Figure 1, this effect was not as large as in the case of the single-slit method. Nakatsuta.

(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 according to the present invention is as follows.
It is considered as follows.

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

For example, when manufacturing Fe-based amorphous alloy ribbon continuously using the normal single slit method, the plate thickness is almost
Although the diameter is only 20 to 40 μm, 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 pressing action is performed by the downstream pouring flow, air entrainment at the rear surface of the paddle is also effectively suppressed.

By the way, in this invention, two or more slit-like orifices can be provided at the tip of the pouring nozzle, but in this case, the puddle formed on the upstream side is not able to sequentially merge the pouring flow on the downstream side while the puddle is not solidified. is essential. 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 heat transfer coefficient will not increase sufficiently, and the amorphous alloy with a thickness of 50 μm or more will not be able to increase the heat transfer coefficient. It is not possible to make thin strips.

For this purpose, the interval between each slit-shaped orifice is preferably about 1 to 5 mm.

A molten alloy having a composition of Fe ₇₈ B ₁₀ Si ₁₂ is continuously supplied from a multi-slit nozzle as shown in Figure 1 above,
When producing an amorphous metal ribbon by rapid solidification on the surface of a cooling roll, the upstream orifice was tilted backwards by 20 degrees, while the downstream orifice was vertical, and the distance between the two orifices was 15 mm. However,
The thickness of the obtained metal ribbon was approximately 66 μm,
It was brittle and crystallized.

Further, the backward inclination angle of the slit-shaped orifice must be gradually reduced toward the downstream side. This is because if the backward inclination angle of the slit orifice on the downstream side is larger than that of the slit orifice on the upstream side, the effect of improving the surface roughness of the side surface of the ribbon roll will deteriorate, especially at the maximum. The slit-shaped orifice on the downstream side should be parallel to the vertical plane, or if it is tilted backwards, the angle of backward inclination should be
It is preferable that the angle is about 10° or less.

Furthermore, the surface roughness of the free surface of the ribbon is largely influenced by the surface roughness of the tip of the front lip in the downstream channel, so the tip of the lip should be smooth, with an average surface roughness Ra of 1.0 μm or less. It is preferable to set it as approximately.

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 it is recommended that the gap be about 0.1 to 0.5 mm. preferable.

(Example) Example 1 An amorphous alloy ribbon was produced from a molten alloy having a composition (at%) of Fe ₇₉ B ₁₂ Si ₈ C ₁ 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.

Γ Backward tilt angle θ of upstream orifice: 30° Γ Backward tilt angle θ of downstream orifice: 0° Γ Distance between nozzle tip and cooling roll surface: 0.3
mm Γ Dimensions of upstream slit opening: 0.5mm×50
mm Γ Dimensions of downstream slit opening: 0.3mm×50
mm Γ Distance between both orifices: 1 mm Γ Circumferential speed of cooling roll: 27 m/s When we started manufacturing the quenched metal ribbon under the above conditions, no paddle break occurred during the manufacturing period, and the plate thickness: Good surface quality at 62μm (Ra: 0.7μm)
Thick and wide amorphous alloy ribbons were continuously obtained.

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

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

Example 2 Molten iron alloy containing 6.5 wt% Si was heated to 0.5 mm×
Through a pouring nozzle with a 10 mm wide slit orifice, the melt was poured onto the surface of a copper alloy cooling roll rotating at a circumferential speed of 40 m/s under the following conditions in the arrangement shown in Figure 1 above. This was then rapidly solidified to produce a crystalline high-silicon steel ribbon.

Γ Upstream orifice backward tilt angle θ: 50° Γ Downstream orifice backward tilt angle θ: 0° Γ Distance between nozzle tip and cooling roll surface: 0.2
mm Γ Distance between both orifices: 3 mm When the molten metal was poured under the above conditions at a temperature of 1550℃, no puddle break occurred, and the plate thickness was approximately 78 μm and the plate width was 10 mm, 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 backward inclination angle of the upstream slit-shaped orifice and the frequency of occurrence of paddle breaks. 1...Pouring nozzle, 2...Cooling roll, 3...
Downstream slit-shaped orifice, 4... Upstream slit-shaped orifice, 5... Paddle, 6... Quenched metal ribbon.

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 is directly poured from the molten metal by rapid solidification. , in manufacturing a metal ribbon, at least the most upstream slit-shaped opening of the plurality of slit-shaped openings is provided with a nozzle flow path that is inclined backward with respect to a vertical plane that includes the rotation axis of the cooling roll that rotates at high speed. molten metal is injected through the injected molten metal, and while the molten metal formed between the nozzle and the roll by the injected molten metal is not solidified, the molten metal flow from the slit-shaped opening located on the downstream side is sequentially merged. A method for producing a quenched metal ribbon, characterized by: 2. Consisting of a cooling roll that receives a falling flow of molten metal and forces it to rapidly solidify into a thin ribbon, and a pouring nozzle equipped with a plurality of slit-shaped orifices that supply 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 plane that includes 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.