JPS60199551A - Method and device for producing thin metallic strip - Google Patents

Abstract

PURPOSE:To obtain a large cooling effect and to obtain a thin metallic strip having a good characteristic and shape even if the thickness is large in the stage of casting continuously the thin metallic strip directly from a molten metal by a one-side cooling method by performing casting in the pressurized atmosphere. CONSTITUTION:The entire part of an apparatus for producing a thin metallic strip is housed in a pressure vessel 5 and the vessel is hermetically closed, then a pressurized gaseous atmosphere 4 is fed into the vessel 5 to pressurize the inside of the vessel 5 in the case of manufacturing said metallic strip by, for example, a one-side cooling method using a single roll method. A pressure regulating valve 8 in the melting section is thereupon opened to attain equality between the inside and outside pressures in the melting section under melting to prevent inflow of a molten metal 10 from a nozzle 7 or intrusion of the gas 4 into the melting section 2. The valve 8 is then closed and a cooling roll 3 is rotated at a high speed. A gas 1 is fed to the section 2 and the back pressure larger than the atmosphere pressure on the outside of the nozzle 7 is exerted to the molten metal 10 to eject and solidify the molten metal 10 onto the roll 3, thereby forming a thin strip 9. The thermal contact between the strip 9 and the roll 3 is improved and the purpose is achieved by the above-mentioned method.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves rapidly solidifying a molten metal (including alloys) on the surface of a moving cooling substrate to continuously form an amorphous metal (alloy) ribbon. Alternatively, the present invention relates to a method and apparatus for manufacturing a crystalline metal (alloy) ribbon.

(Prior art) Various methods have been disclosed for the continuous production of thin strips from molten metal (continuous molten metal quenching method), but the method mainly used for mass production today is the melting method. This is a method in which metal is solidified by impact from a nozzle having an opening in a predetermined shape under a predetermined pressure onto a cooling substrate facing the nozzle opening to form a continuous ribbon.

Although this method has features that are advantageous for industrialization, such as easy production of wide ribbons, little damage to the cooling substrate, and relatively easy control of manufacturing parameters, the surface of the produced ribbons is It had drawbacks such as poor properties and low cooling capacity. One reason for the poor surface quality is that the free surface (the surface that does not come into contact with the cooling substrate) is not constrained, resulting in instability of the puddle (hereinafter referred to as puddle) and local non-uniformity in the cooling rate. The other problem is that many small dents are formed on the substrate side of the ribbon due to the entrainment of air adsorbed on the surface of the cooling substrate.

The reason for the low cooling capacity is that it is single-sided cooling, the paddle is in contact with the cooling board with a relatively small force, and the thin strip has many dents on the board surface as mentioned above, which causes heat to heat up. It depends on K, such as reducing physical contact.

A number of methods have been proposed to eliminate these drawbacks of ribbon production by single-sided cooling. For example, as a method for reducing the dents on the substrate side of the thin strip, there is a method described in Japanese Patent Application Laid-Open No. 54-76432 that prevents air from being entrained, a method described in JP-A-54-76432,
A method of casting in 6 gas has been proposed (Japanese Patent Application Laid-Open No. 58-32550). Another method of increasing the cooling capacity by extending the contact time between the ribbon and the cooling substrate is to blow gas onto the free surface of the ribbon on its exit side (U.S. Patent No. 3).
A number of methods have been proposed, including a method of pressing an auxiliary roll or belt against the free surface of the ribbon (Japanese Patent Application Laid-open No. 54-76435 and Japanese Patent Application Laid-open No. 54-23030). However, all of these methods are applied after the alloy has completed solidification and are either ineffective or cannot be adopted industrially from the viewpoint of economy and mass production.

The present invention provides a method and apparatus for fundamentally improving the lack of cooling capacity, which is a drawback of manufacturing ribbons by single-sided cooling.

(Objective of the Invention) The purpose of the present invention is to obtain a large cooling effect that could not be achieved with the conventional technology as described above, and as a result, it is possible to produce a metal (alloy) with good properties and shape even with a large thickness.
This made it possible to manufacture thin ribbons.

(Structure and operation of the invention) The present invention aims to produce a metal ribbon having a large thickness and good shape and surface properties by a method that essentially increases the cooling rate as described below.

When a thin metal strip is made by a single-sided cooling method such as a single roll method, a belt method, or a centrifugal quenching method, the molten metal spouted onto the surface of a moving cooling substrate forms a pool (hereinafter referred to as a paddle) on the substrate. solidification progresses from the part of the nozzle in contact with the substrate.

In order to make a thin strip with a large thickness, the solidification progress rate,
That is, it is necessary to essentially increase the cooling rate during solidification. As a measure to dramatically increase the cooling rate during solidification, the present invention is characterized in that the casting process is carried out in a pressurized atmosphere. As a result, the unsolidified ribbon immediately after being pulled out from the paddle and the master dollar is strongly pressed against the cooling substrate, increasing thermal contact and significantly improving the cooling rate.

An example of the method of the present invention will be explained with reference to the drawings. Figure 1 shows the case where the main parts of the ribbon manufacturing equipment, such as the melting part (crucible), molten metal supply part (nozzle), and cooling substrate (roll), are all housed in a pressurized container. Figure 3 shows the case where only the entire melting section and molten metal supply section and a part of the cooling substrate (roll) are placed in a pressurized atmosphere, and Figure 3 shows a case where only the melting section and the vicinity of the nozzle of the molten metal supply section are placed in a pressurized atmosphere. This shows the case where lr'i is inside.

In each of the above figures, l is a molten metal jetting gas, 2 is a melting section that melts the raw material prepared into a desired alloy composition and holds it as the molten metal 10, and 3 is a cooling substrate formed in the shape of a rotating roll (hereinafter referred to as a cooling roll). It is. 5 is a pressurized container to which atmospheric pressurized gas 4 is supplied, 6 is a heating mechanism for the melting section 2, and 7 is a nozzle provided at the lower end of the melting section 2. As illustrated in FIG. 4, it is appropriate to use multiple nozzles in which the opening 1 from which the molten metal spouts out is slot-shaped and two or more are arranged in parallel in the direction of movement of the cooling roll. 8 is a melting section internal pressure regulating valve, and 9 is a manufactured ribbon. Further, in FIGS. 2 and 3, 5' is a pressurized atmosphere cover.

The method of manufacturing a metal ribbon according to the method of the present invention will be explained with reference to the case shown in FIG. In this case, the entire ribbon manufacturing apparatus is housed in a pressurized container 5 and the entire device is hermetically sealed. Therefore, before the start of casting, the periphery pressurized gas 4 is pumped into the pressurized container 5. The inside of the pressure vessel 5 is pressurized. Then, the melting section internal pressure regulating valve 8 is opened to equalize the pressure inside and outside the melting section during melting. This is to prevent pressurized atmosphere gas from entering into the melting section 2 or into the melting section 2 into which the molten metal 10 flows from the nozzle 7 . After the melting is completed, the melting section internal pressure regulating valve 8 is closed.

To perform V4 production, the cooling roll 3 is rotated at high speed, and the molten metal l
In order to blow out O, molten metal blowout gas 1 is sent into the melting section 2,
A back pressure is applied to the molten metal, and the molten metal 10 is ejected and solidified onto the cooling roll 3 to form a ribbon 9.

The magnitude of this back pressure must be greater than the ambient air pressure outside the nozzle 7. The specific ejection pressure is determined by taking into account the required thickness of the ribbon, the distance between the nozzle 7 and the cooling roll, the circumferential speed of the cooling roll, etc.

In this case, in the present invention, since the casting is carried out under pressure, the thermal contact between the ribbon and the cooling roll is improved, and therefore a ribbon with a good shape and a large thickness can be obtained. . In addition, in the case shown in Fig. 2 and N3, the entire device is not housed in a pressurized container, and only the casting part is shielded with a pressurized atmosphere cover 5', which is not completely sealed and the cover 5 is not completely sealed. ' and the cooling roll 3 through a narrow gap formed between the cooling roll 3 and the outside air (atmospheric pressure).

Therefore, in order to maintain the pressure inside the cover 5' higher than atmospheric pressure, it is necessary to continue sending the atmosphere pressurized gas 4 into the cover 5'. The pressure and flow rate of the gas required to secure a predetermined pressure depend on the size of the gap communicating with the outside air (the gap between the lower end of the cover and the cooling board in the example in Figure 2), and the shape of the inner surface of the gap (the gap between the lower end of the cover and the cooling board in the example in Figure 2). In Figure 2, it depends on the shape of the lower end of the cover), etc., so it should be determined experimentally depending on the actual condition of the device.

Compressed air, inert gas (N2, ArrHe), etc. are used as the gas to be pumped into the container or the cover. Patent application No. 58-41266 to further enhance the cooling effect
It is also possible to use a humidified atmosphere as disclosed in the above publication.

The higher the pressure of the atmosphere around the nozzle, the better! This is advantageous for improving the thermal contact between the dowel and ribbon and the substrate.

When producing a wide ribbon using the method of the present invention, it is preferable to use a nozzle for spouting the molten metal with an opening 11 in the form of a slot, as shown in FIG. Even one of the slots is 2
There may be two or more, and if there are two or more, those arranged in the direction of movement of the cooling roll are used. When a ribbon with a large thickness is required, it is advantageous to increase the number of slots. For example 0.
4 When three or more tm width slots are lined up, the plate thickness is 60 μm.
A wide ribbon with a good shape can be manufactured as described above. Note that the length of the slot can be arbitrarily selected depending on the width of the ribbon to be obtained. Casting in a pressurized atmosphere using a multi-slot nozzle yields a thick amorphous alloy ribbon with good shape. When applied to Fa-based alloys that require a high critical cooling rate to become amorphous, that is, are difficult to become amorphous, a thin ribbon with a thickness of 60 μm or more can be easily produced.

When using the conventional method, the maximum thickness of Fe-8i-B alloy that can be made amorphous was about 42 μm (Luborsk
y S +IEgE Traus, Magnetics
+MAG-18 (1982) 1385).

Next, an example will be given and explained.

Example 1 CujJ sealed in a pressurized container as shown in FIG.
Ingredients”110.5SI6.58 using a single roll device 4
A practical experiment was carried out to produce a ribbon of 12C1 (at%) alloy.

A master alloy having the above composition was placed in a quartz glass crucible having a slot-shaped opening of 0.6 m x 25 m on the bottom, and melted by high-frequency heating in artane gas. After the melting temperature reaches 1270°C, air pressurized by a compressor is sent to the pressurized container, and the pressure inside the container (i.e. the pressure outside the storage part) is 2 kg/
an2 (based on atmospheric pressure). At this time, the internal pressure regulating valve of the melting section is opened in advance, and the pressure inside and outside of the melting section is kept equal. After that, the same casting operation as energization is performed. However, the molten metal ejection pressure is 2.4 kg/c.
m2, the distance between the nozzle bottom surface and the roll was 0.2 m, and the peripheral speed of the roll was 25 m/IJ). The thickness of the fabricated thin strip was 50 μm on average, and it was possible to bend the thin strip closely without breaking in 1800 bending tests.

On the other hand, a ribbon of the same composition cast under atmospheric pressure for comparison broke before being brought into close contact with the 180° bend, even though the thickness was 45 μm, which was thinner than that of the above example. This shows that the casting method of the present invention, which is carried out in a pressurized atmosphere, has a remarkable effect on improving the cooling rate of the ribbon. However, the manufacturing conditions for the comparative material were a jetting pressure of 0.35 kg7cm2,
Distance between nozzle bottom and roll: 0.2■, peripheral speed of roll: 22
%/sec.

Example 2 An alloy having the same composition as in Example 1 was made into a ribbon using a Cug single roll device in which only the periphery of the melting part and nozzle part can be placed in a pressurized atmosphere as shown in FIG. However, the shape of the nozzle is a multi-nozzle with three slots arranged in parallel as shown in Figure 4, melting temperature 1270°C, internal positive pressure 1.5-2, and molten metal ejection pressure 1.9 kl. //c
rtt2, the distance between the nozzle bottom surface and the roll was 0.2 m, and the peripheral speed of the roll was 25 nV/sec. The thickness of the produced ribbon was about 70 μm, and it had enough ductility to not break when bent at 180°.

On the other hand, the pressure inside the cover is atmospheric pressure, and the molten metal ejection pressure is 0.35.
A thin strip cast under the same conditions as above except that the thickness was 10 n2 had a thickness of 62 μm, but it broke before being brought into close contact with the 180° bend. This shows that the casting method of the present invention, which is carried out in a pressurized atmosphere, has a remarkable effect on improving the cooling rate of the ribbon.

(Effects of the Invention) As explained above, according to the present invention, the contact force between the molten metal spouted from the nozzle and the cooling substrate can be increased,
Therefore, since the cooling capacity can be improved, a metal ribbon having a large thickness and a good surface shape can be manufactured.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams showing embodiments of the present invention,
FIG. 4 is a bottom view of the bifurcated nozzle. 1: Molten metal spouting gas, 2: Melting part, 3: Cooling substrate, 4: Pressurized atmosphere gas, 5: Pressurized container, 5': Pressurized atmosphere cover, 6: Heating mechanism, 7: Nozzle, 8: Mechanism internal pressure regulating valve,
9: Thin ribbon, lO: Molten metal, 11: Opening. Figure 1 Figure 3

Claims (1)

[Scope of Claims] (Li) When continuously casting a metal ribbon directly from molten metal using the single-sided cooling method, the casting must be performed in a pressurized atmosphere. (2) The metal according to claim 1, characterized in that only a narrow space including a sump for molten metal during casting is in a pressurized atmosphere. A method for manufacturing a thin ribbon. (3) A metal thin strip characterized in that a casting mechanism consisting of a cooling substrate, a nozzle whose tip faces the cooling substrate, a melting section connected to the nozzle, etc. is housed in a pressurized chamber. manufacturing equipment.