JPH0428459A - Apparatus for producing rapidly solidified wide strip and product - Google Patents

Abstract

PURPOSE:To enable production of a rapidly solidified wide strip by using a crucible, which has oval-shape or rectangular cross section and a nozzle opening part for injecting molten metal at the bottom part, and a high frequency induction work coil for melting sample positioned outside of the above crucible. CONSTITUTION:The crucible 1 for producing the rapidly solidified wide strip has the oval-shape or rectangular shape in the cross section to the depth direction and the nozzle opening part for injecting the molten metal at the bottom part. The high frequency induction work coil 2 for melting sample, which positions outside the above crucible 1 and has oval shape and rectangular shape in the cross section to depth direction, is provided. By forming the cross section of crucible 1 to the oval shape or rectangle, strength of the bottom part of crucible 1 is improved and deformation is scarcely developed. Further, by using the work coil 2 for high frequency induction having the oval shape or rectangular shape in the cross section, efficiency of melting is remarkably improved and the production time can be shortened.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention rapidly solidifies a molten metal (including alloys; the same applies hereinafter) on the surface of a moving cooling substrate, and continuously forms an amorphous metal or a crystalline metal. The present invention relates to equipment and products for manufacturing wide metal ribbons.

[Conventional technology]

Various methods have been disclosed for the continuous production of thin strips from molten metal (continuous liquid quenching method), but in all of them, molten metal is passed through a nozzle having an opening of a predetermined shape into a predetermined shape. The liquid is ejected onto the moving cooling substrate facing the nozzle opening at a pressure of 100 mL, and is solidified into a continuous ribbon. Important manufacturing factors at this time include the shape of the nozzle opening, the relative arrangement of the nozzle and the cooling substrate, the pressure at which molten metal is ejected from the nozzle, and the moving speed of the cooling substrate. Generally, the conditions for these manufacturing factors tend to become narrower and stricter as the width of the ribbon becomes wider.

A typical method conventionally disclosed as a method for producing wide ribbons is, for example, "Continuous casting method of metal strip and apparatus used therein" disclosed in Japanese Patent Application Laid-Open No. 53-53525. The outline is that a slot nozzle with a rectangular opening is 0.03 to 1!11
The rectangular openings are arranged substantially perpendicularly to the moving direction of the surface of the cooling substrate.
A continuous strip is produced by sending molten metal from a slot nozzle onto a cooling substrate moving at a predetermined surface speed of 0 to 2000 m/min, bringing it into thermal contact and rapidly solidifying it. In principle, this conventional method has no restrictions on the width of the ribbon. In other words, by increasing the length of the rectangular opening of the nozzle (the length of the opening measured in the direction perpendicular to the direction of movement of the cooling substrate), the width of the ribbon can be increased. However, in reality, as the length of the rectangular opening increases, it becomes difficult to maintain the balance of the opening during casting, and the thickness of the ribbon becomes uneven, especially in its width direction. By the way, in a thin strip with a width of 25 mm,
Although it is currently possible to suppress the plate thickness deviation to about 5 to 10%, it is difficult to suppress it to 10% or less when the thickness becomes 150 mm. A ribbon with a large plate thickness deviation is undesirable, for example, when it is used as a magnetic material and is laminated or wound, since the space factor decreases. For this reason, in the conventional method for providing rapidly solidified ribbons as industrial materials, there is a substantial technical limit to the width of the ribbons.

In order to remove the limitations on the width of Sakae and cold-solidified ribbons that had existed up to that time, the present inventors, for example,
In Publication No. 0, a new casting method was proposed.

In this method, molten metal is spouted from a plurality of openings on a moving cooling substrate, which are arranged approximately perpendicular to the direction of movement, and each having an angle of 10 to 80 degrees with respect to the direction of movement, to rapidly cool the substrate. This is a method for manufacturing a metal ribbon characterized by solidification.

This method has made it possible to manufacture a ribbon with a thickness deviation of 10% or less even if the width of the ribbon is 150 m or more. In other words, the conventional limitations on the width of thin strips can be removed.

On the other hand, equipment for producing rapidly solidified ribbons basically consists of a roll made of a metal with high thermal conductivity such as copper as a moving cooling body, a crucible for holding the sample, and melting equipment for melting the sample. It is the Lord who becomes. Also - boat fishing,
The crucible has a nozzle at its bottom for spouting molten metal onto a roll after melting the sample. As for the dissolution method,
It mainly relies on high frequency induction. The shape of the crucible used is generally cylindrical, and the work coil for high frequency induction melting used for melting is also cylindrical.
JP-A-53-53525 discloses a work coil for melting that has a circular cross section in the depth direction to match a cylindrical crucible.

The present inventors investigated the production of a ribbon with a width of 150 m or more using the above-mentioned casting method proposed by the present inventors, and actually attempted a production experiment. Then, the width of the thin strip is widened (
They discovered a new problem: it is difficult to manufacture wide ribbons using conventional cylindrical crucibles and work coils. In other words, in order to increase the ribbon convergence, it is necessary to increase the number of openings for ejecting molten metal.
Naturally, the area at the bottom of the crucible must be increased. In other words, the diameter of the cylindrical crucible must be increased. However, if the diameter of the crucible becomes too large, the bottom of the crucible will bend while holding the molten metal after melting, and when it is ejected onto the rolls rotating at high speed, it will collide with the rolls, making it impossible to obtain a ribbon. Even if there is no collision, if the distance between the roll and the nozzle becomes uneven in the width direction of the ribbon, it will be difficult to obtain a ribbon with a good shape and a small thickness deviation. In order to obtain a ribbon with a small thickness deviation, it is necessary to keep the distance between the roll and the nozzle as constant as possible in the width direction of the sheet. In order to solve this bending caused by increasing the diameter of the crucible, it is conceivable to make the bottom of the crucible thicker, for example. However, if the bottom of the crucible is thick (then the bottom of the nozzle (the part closest to the roll surface)
As the temperature drops, the molten metal solidifies here, causing nozzle clogging. Furthermore, in order to prevent this, heating the nozzle bottom from the outside may be considered, but this would complicate the device and increase the manufacturing cost of the device.

Furthermore, if the diameter of the crucible is too large, the efficiency of high-frequency induction will deteriorate (difficult to melt the sample), and the melting time will be quite long. For example, in the case of a crucible with a diameter of about 300 mm, the number It takes nearly one hour to dissolve the glare, which increases the time required to manufacture the ribbon.Extending the manufacturing time poses a problem in terms of productivity.

As a method to solve the problem of crucible deflection and melting efficiency, for example, by arranging multiple crucibles in the width direction of the ribbon,
There is also a method of setting melting work coils for each crucible (Proc.

of 5th Int, Conf, on Rapi
dly Quenched Metals (1985)
p, 1591). However, producing wide ribbons by this method appears to require sufficient control over the placement of each crucible. This is because, for example, if the positions of the nozzle openings of each crucible are separated in the ribbon width direction, the ribbons will not be connected in the width direction (in other words, they will not become a wide ribbon but will be split). On the other hand, if there is overlap, the plate thickness will increase at that point (
(The variation in plate thickness in the width direction becomes large). Therefore, this method is unlikely to be suitable for stable production in commercial mass production.

[Problem to be solved by the invention]

The present invention was devised in order to solve 2. problems related to manufacturing technology and productivity in crucibles and manufacturing equipment, which were obstacles to increasing the width of cold-solidified ribbons. In other words, even if the number of openings at the bottom of the crucible is increased (even if the II band width is increased), the crucible hardly bends and the time required for melting does not increase, allowing stable mass production. It is an object of the present invention to provide a manufacturing apparatus and a wide rapidly solidified ribbon produced by such an apparatus.

[Means and effects for solving the problem] The gist of the present invention is to provide a wide quenching device having an elliptical or rectangular cross section in the depth direction and having a nozzle opening at the bottom for spouting molten metal. A method for manufacturing a wide rapidly solidified ribbon, characterized by having a crucible for manufacturing a solidified ribbon, and a high-frequency induction work coil for sample melting having an elliptical or rectangular cross section in the depth direction located outside the crucible. The device, and furthermore the present device, produces a wide rapidly quenched and solidified ribbon with a width of 300 m+ or more and good thickness variation.

That is, the inventors have developed a wide 2. In order to prevent the bending of the crucible that occurs when manufacturing cold-solidified ribbons, instead of the conventional cylindrical crucible, a crucible with an elliptical cross section in the depth direction as shown in Figure 1 was used. Or they came up with a rectangular shaped crucible. A crucible with such a shape can improve the strength of the bottom of the crucible, and in actual use, it was found that melting and spouting were possible with almost no bending of the bottom of the crucible during melting. The apparatus of the present invention comprises a crucible having such a shape and a work coil that enables use of this crucible.

Furthermore, by using a work coil with an elliptical or rectangular cross section in the depth direction as a work coil for high frequency induction, compared to the conventional case of using a cylindrical work coil with a large diameter, high frequency induction can be achieved. It has been found that the efficiency of dissolution has been considerably improved, that is, it has become easier to dissolve the sample, and it has also been possible to shorten the manufacturing time at the same time.

The shape of the crucible used in the apparatus of the present invention will be explained in detail with reference to FIG. 1. FIG. 1(a) shows a crucible with an elliptical cross section in the depth direction of the crucible. Further, FIGS. 1(b) and 1(C) show a crucible whose cross section in the depth direction of the crucible is rectangular. Here, the shape having a rectangular cross section in the depth direction includes a shape in which the short side has a curvature (for example, the shape of a crucible as shown in FIG. 1(C)). All the crucibles shown in Figure 1 have a flange attached to the top of the crucible, but this is necessary for attaching the crucible to the device.In the present invention, the method for attaching the crucible to the device is However, the crucible does not necessarily have to have a flange as long as it can be attached to the device by another method.

Furthermore, the shape of the work coil used in the apparatus of the present invention basically corresponds to the shape of the crucible shown in FIG. It is similar in shape to that.

In addition to the shape shown in FIG. 1, a shape in which the long sides of both the crucible and the work coil are recessed is also considered to be effective. However, crucibles and work coils having such shapes are difficult to manufacture, so they are not very preferable.

Furthermore, the shape of the crucible and work coil will be specifically explained with dimensions listed. The device of the present invention can generally be said to be effective when the width of the ribbon is 200 m5+ or more, but especially when the width of the ribbon is 300 m5+ or more. The effect can be fully demonstrated. In other words, if the length of the long side of the crucible is 300 or more, if the length of the long side of the crucible is 300 or more,
In order to suppress the occurrence of deflection at the bottom of the crucible during sample melting, it is desirable that the length of the short side of the crucible be 100 m or less. Also, the dimensions of the work coil will be discussed later, but
Also from the point of view of sample dissolution efficiency, it is desirable that the temperature be 100 or less. When using a crucible with a long side length of 300 ma or more and a short side length of 100 m++ or more, the dimensions of the work coil will be slightly larger than the dimensions of the crucible. This is because there needs to be a gap around the crucible for installing insulation material in order to keep the molten metal warm.
For example, a work coil with a long side length of 330 m++ or more and a short side length of 130 m++ or less is desirable.

Further, regarding the height of the work coil, since the optimum number of turns of the coil differs depending on the amount of sample to be dissolved (height differs), the height is not particularly limited in the present invention.

The nozzle opening of the crucible used in the present invention consists of a plurality of elongated parallelogram, trapezoid, ellipse, etc. openings, and forms an angle of 10 to 80 degrees with respect to the longitudinal direction, and each opening is cooled. These nozzles are arranged approximately perpendicular to the direction of movement of the substrate. In addition, the shapes of the plurality of openings are such that adjacent openings partially overlap in the direction of movement of the cooling board, and the total length of the openings in the direction of movement of the cooling board is
It is also possible to use nozzles arranged so that they have approximately the same length over the range in which the openings are present in the direction of movement of the cooling substrate. Such a nozzle allows the production of wide ribbons. In other words, it is possible to manufacture a ribbon with good thickness variation even if the width is 300 mm or more. For any type of nozzle, the optimal shape of the nozzle opening varies depending on manufacturing factors such as the type of alloy used, so an appropriate value is selected depending on the manufacturing factors. A preferred shape of the nozzle opening will be shown later as an example.

As an example of the apparatus of the present invention, FIG. 2 shows an apparatus for producing a wide rapidly solidified ribbon having a work coil having a rectangular cross section in the depth direction. In addition, basically one roll, a peeling plate or peeling nozzle for peeling the ribbon from the roll surface (in the case of peeling using gas pressure), a motor for rotating the roll, a motor for lifting and lowering the crucible, It consists of a high frequency heating power source, etc. Of course, the present invention can also be applied to improved types, such as an auxiliary roll, a device attached with a roll surface temperature control device, or a device covered with a chamber so that casting can be performed under reduced pressure, in a vacuum, or in an inert gas. I can do it.

Next, other casting conditions employed in the apparatus of the present invention will be explained. First, the distance between the nozzle at the bottom of the crucible and the roll is in the range of 0.05 to 3 m, and the optimum value is selected depending on the nozzle structure and other manufacturing factors. The ejection pressure of the molten metal is in the range of 0.01 to 3 kg/c4, and the rotational speed (surface speed) of the roll is in the range of 5 to 60 m/sec. Optimal values for these conditions are also selected depending on the nozzle structure and other manufacturing factors. When actually manufacturing a wide ribbon using the apparatus of the present invention, it is preferable that the distance between the bottom of the crucible and the roll during sample melting be wider than the distance during casting as described above. The optimal spacing position between the bottom of the crucible and the roll is memorized in advance assuming the time of casting, and then the sample is melted after being moved into the work coil. After melting, the roll rotation and ejection pressure are set, and then the crucible is returned to the pre-memorized optimal spacing position with respect to the rolls, and casting is started. Therefore, it is preferable that the work coil be located a little distance from the roll surface.

The composition of the ribbon that can be produced by the apparatus of the present invention is advantageous in the case of metals that tend to become amorphous or metals that are difficult to process by rolling, but are not limited to these.

Furthermore, regarding the thickness of the ribbon produced by the apparatus of the present invention, such a continuous liquid quenching method is basically not suitable for producing very thick ribbons, and the thickness of the ribbon produced by the apparatus of the present invention is The thickness of the ribbon is approximately 0.5 m or less. As for plate thickness variation, as mentioned above, it worsens as the plate width increases, but the apparatus of the present invention made it possible to manufacture a wide ribbon with good plate thickness variation. In particular, it has become possible to manufacture ribbons with good thickness variation, even for ribbons with a width of 300 m or more, which was previously difficult to manufacture.

As a method to quantitatively show the variation in the thickness of a thin strip, the thickness calculated from the weight and density of the thin strip (hereinafter referred to as weight thickness) relative to the thickness measured using a micrometer (hereinafter referred to as maximum thickness) is calculated. There is a method using ratios. Using this ratio to define the thickness variation of a ribbon with a width of 300 m or more obtained by the apparatus of the present invention, it is a ribbon that exhibits a thickness variation of 90% or more in the ratio of weight thickness to maximum thickness. .

〔Example〕

Next, examples of the present invention will be described.

Example 1 As an apparatus of the present invention, an apparatus for manufacturing cold-solidified ribbon was manufactured using two single rolls consisting of a sample melting work coil having a rectangular cross section in the depth direction of 350mm on the long side and 80cm on the short side. Using this method, an amorphous ribbon having a plate width of 300 mm was manufactured. In addition, as a cooling roll, the width is 6001111. Diameter 6
A crucible made of copper was used, and the crucible was made of quartz and had a rectangular cross section in the depth direction of 320 mm on the long side and 50 mm on the short side. Also,
The nozzle shown in Figure 3 was used as a nozzle at the bottom of the crucible, and each parameter was set as a=2wi, d=1m+, b=0.
．． 7■, α=30°, and the number of openings was 175. The composition is FetzCo+oMoJ+zC4(atχ)
2 kg of the alloy was melted at 1350°C and spouted onto a roll to produce a ribbon. The time required to dissolve the sample was 20 minutes.
It was able to dissolve in a short time. Other casting conditions are injection pressure 0, 5
kg/d, and the roll surface speed was 25 m/sec.

The fabricated ribbon has a width of 300mm, a thickness of 45n (measured by micrometer), and a thickness of 18mm on both the free and rolled sides.
It did not break due to 0' close contact bending. Further, the results of X-ray diffraction and differential thermal scanning (DSC) analysis showed an amorphous state.

In order to examine the thickness variation of the obtained ribbon, samples of 5 cm length were taken every 2 m in the longitudinal direction of the ribbon, and the maximum thickness of each sample was measured.

Furthermore, for each sample, the weight thickness (specific gravity 7, 2
6) was calculated, and the ratio of this weight thickness to the maximum thickness was determined. The average value of the obtained ratios was as high as 96.5%. This suggests that there was almost no deflection of the crucible during sample dissolution.

Example 2 Using the same equipment as Example 1, composition Feq2.5sth
, s(wtχ) alloy is melted at 1500℃,
A thin ribbon was prepared by squirting it onto a roll. The time required to dissolve the sample was 25 minutes, and the sample was dissolved in a short time. Other casting conditions are jet pressure 0.5kg/d, roll surface speed 20m.
/second.

The produced ribbon had a plate width of 300 nm and a plate thickness of 50 nm (measured with a micrometer).

In order to examine the variation in thickness of the obtained ribbon, the ratio of weight thickness (specific gravity 7.48) to maximum thickness was determined in the same manner as in Example 1. The obtained value was as high as 94.3%. This suggests that there was almost no deflection of the crucible during sample dissolution.

Example 3 A crucible with a rectangular cross section in the depth direction with 250 mm on the long side and 50 mm on the short side was used, and the board width was 22 mm.
We manufactured an amorphous thin ribbon with a high quality. The shape of the nozzle opening section is the same as that in Example 1, and the number of closing sections is 1.
There were 28 pieces. Note that the equipment configuration used was the same as in Example 1 except for the crucible. Alloy 1.5k as in Example 1
g was dissolved at 1350'C7 and spouted onto a roll to produce a ribbon.

The time required to dissolve the sample was 22 minutes, indicating that the sample could be dissolved in a short time. Other casting conditions were an injection pressure of 0.5 kg/rffl.

The roll surface speed was 25 m/sec.

The width of the manufactured thin strip board is 220R, the board thickness is 43 catties (measured with a micrometer), and both the free surface and roll surface are 1.
No breakage occurred during 80' close bending. In addition, X-ray diffraction, D
The results of SC analysis showed an amorphous state.

In order to investigate the thickness variation of the obtained ribbon, the ratio of the weight thickness (specific gravity 7.26) to the maximum thickness was determined in the same manner as in Example 1. The obtained value was as high as 96.6%. From this, it is considered that there was almost no deflection of the crucible during sample melting.Example 4 As an apparatus of the present invention, the long side @ 450 m and the short side 90 [1
An amorphous ribbon with a plate width of 400 mm was manufactured using a single-roll rapid solidification ribbon manufacturing apparatus consisting of a sample melting work coil having a long sword-shaped cross section in the depth direction. Note that the cooling roll is the same as in Example 1.

As a crucible 7, the dimensions are 420 m on the long side and 60 m on the short side.
The cross section in the depth direction was rectangular. In addition, the bameter of the nozzle at the bottom of the crucible is as shown in Example 1.
The number of openings was set to 234. 3 kg of the same alloy as in Example 1 was melted at 1350° C. and ejected onto a roll F to produce a ribbon. The time required to dissolve the sample was 25 minutes, and the sample was dissolved in a short time. Other casting conditions were a jetting pressure of 0.3 kg/d, a roll surface speed of 25 m/sec, and U7.

The fabricated ribbon has a width of 40 (1 m) and a thickness of 43 nm (measured with a micrometer), and has a thickness of 1 m on both the free side and the roll side.
It did not break after 80° close bending. In addition, X-ray diffraction, D
The results of SC analysis showed an amorphous state.

In order to investigate the thickness variation of the obtained ribbon, the ratio of the weight thickness (specific gravity 7.26) to the maximum thickness was determined in the same manner as in Example 1. The obtained value was as high as 95.6%. This suggests that there was almost no deflection of the tube during sample dissolution.

Example 5 As a device of the present invention, the long side is 560 m5. Using a single-roll rapid solidification ribbon manufacturing device consisting of a work coil for sample melting whose cross section in the depth direction of the short side is rectangular, an amorphous ribbon with a width of 500 m+ was manufactured. went. Note that the cooling roll is the same as in Example 1. As a crucible, the dimensions are 530cm on the long side and 60m on the short side.
A crucible having a rectangular cross section in the depth direction was used, and the nozzle at the bottom of the crucible was the same as in Example 1, and the number of openings was 293. 3 kg of the same alloy as in Example 1 was melted at 1350'C2 and spouted onto a roll to produce a ribbon. The time required to dissolve the sample was 25 minutes, indicating that the sample could be dissolved in a short time. Other casting conditions were injection, specific pressure □, 35 kg/cd, and roll surface speed 25 m/sec.

The fabricated ribbon has a width of 500 m, a thickness of 46 mm (measured by micrometer), and a thickness of 18 mm on both the free surface and the rolled surface.
It broke at 0° close bending and became 2-point.

Moreover, the results of X-ray diffraction and DSC analysis showed an amorphous state.

In order to investigate the thickness variation of the obtained ribbon, the ratio of the weight thickness (specific gravity 7.26) to the maximum thickness was determined in the same manner as in Example 1. The obtained value was as high as 95.0%. This suggests that there was almost no deflection of the crucible during sample dissolution.

[Comparative example] Long side 11350m, short side 140wnO)H side rt
An amorphous ribbon having a width of 300 m was manufactured using a single-roll rapid solidification ribbon manufacturing apparatus comprising a sample melting work coil having a rectangular cross section relative to iJL'-. Note that the cooling roll is the same as in Example 1. As a crucible, the dimensions are 320cm on the long side and 1!11'0 on the short side.
The cross section in the depth direction of +w was rectangular. Further, the nozzle at the bottom of the crucible is the same as that in Example 1. 2 kg of the same alloy as in Example 1 was weighed at 1350″
It was dissolved in C and spouted onto a roll to produce a ribbon. The time required to dissolve the sample was 45 minutes, which was longer than in the example. Other casting conditions are injection pressure 0.3kg.
/cii.

The roll surface speed was 25 m/sec.

The width of the obtained ribbon was 300 cm, but when the thickness was examined in the width direction of the ribbon, it was found that it was slightly thinner near the center of the width of the ribbon. Although the lower part of the crucible did not collide with the rolls during casting, the crucible was bent during melting, and the distance between the crucible and the rolls became uneven, causing the thickness of the ribbon to become defective in the width direction. Seem. In order to investigate the variation in the thickness of the Il band, the thickness was measured in the same manner as in Example 1.

The maximum thickness is 52M, and the weight thickness (specific gravity 7, 2
The ratio of 6) was 88.6%. This value is lower than that in the examples and is considered to be insufficient for use as an industrial material.

〔Effect of the invention〕

As explained above, by adopting the apparatus of the present invention, it has become possible to manufacture cold-solidified ribbons with arbitrarily wide widths without decreasing the space factor (small thickness fluctuations). .

Since the amorphous alloy produced by the apparatus of the present invention can be made into a wide ribbon, it can be applied to large-scale winding transformers or stacked transformers. Furthermore, by plating with a highly conductive metal such as Cu plating, it is suitable for electromagnetic shielding materials, especially blind materials for electromagnetic darkrooms. The maximum width of the amorphous alloys available so far is 15 cm, so steps such as soldering were required to widen the width, but this can be omitted. In addition, it can be used as a composite reinforcing material by slitting it into thin wires, and Cu
By plating it into a spiral, it can be used as an electromagnetic shielding material for coaxial cables.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the shape of the crucible used in the device of the present invention, Fig. 2 is an explanatory diagram showing the device of the present invention, and Fig. 3 is a diagram showing the shape and arrangement of the openings of the nozzles attached to the bottom of the crucible. It is an explanatory diagram. 1; Crucible, 2; Work coil, 3; Cooling roll, 4
; wide ribbon, 5; ribbon peeling nozzle, 6; multi-hole nozzle,
7: Opening, 8: Cooling board patent applicant Nippon Steel Corporation

Claims (3)

[Claims] (1) A crucible with an elliptical or rectangular cross section in the depth direction and having a nozzle opening at the bottom for spouting molten metal, and a crucible with an elliptical or rectangular cross section in the depth direction located outside the crucible. An apparatus for producing a wide rapidly solidified ribbon, characterized by having a rectangular-shaped high-frequency induction work coil for sample melting. (2) Short side length is 100mm or less, long side length is 30mm
2. The wide rapidly solidified ribbon manufacturing apparatus according to claim 1, comprising a crucible having a diameter of 0 mm or more and a high frequency induction work coil for sample melting surrounding the outside of the crucible. (3) A wide rapidly solidified ribbon having a width of 300 mm or more and good thickness variation, produced by the apparatus according to claim 1 or 2.