JPS599259B2 - How to make metal strips - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A continuous metal strip of crystalline and non-quality (glassy) structure is produced in the melt by depositing the molten metal on the surface of a rapidly moving cooling body where it is rapidly cooled and solidified. Direct production methods are known.

The cooling body may be a rotating wheel, cup or cylinder, and the molten metal may be deposited on the outer surface of the wheel or on the inner surface of the cup or cylinder.

The cooling body may also be a moving belt, usually an endless belt.

Metals can be produced by injecting molten metal onto a cooled surface, by moving the cooled surface in contact with a meninuccus or suspended droplet of molten metal and drawing out a film of metal, or by placing the cooled surface of a cooling body in a bath of molten metal. It can be deposited on the cooling surface of the cooling body by various methods such as dipping.

The surface of the cooling body must meet several requirements.

First of all, it must be capable of wetting by molten metal.

If this is not the case, the formation of a continuous strip will not occur.

Second, it must not react with molten metal.

That is, it must not be attacked by molten metal and must not be capable of welding molten metal to its cooling surface.

If this is not the case, the metal strip cannot be cleanly peeled off from the cooling surface.

Third, it must have good thermal conductivity.

This rapidly removes heat, causes the molten metal to rapidly solidify and form a glassy structure, and the metallic glass sludge
- This is because it is necessary to optimize the characteristics of the IJ tap, especially its magnetic characteristics.

Finally, it must have sufficient wear resistance in the continuous production of metal strips by the above-mentioned quench casting method.

Wear resistance is a very important element of coolant physical properties.

The high thermal conductivity metals previously proposed to provide the coolant surface, such as copper, copper or silver, do not have the necessary anti-wear properties.

Other metals, such as stainless steel, are expected to have good wear resistance properties, but have drawbacks in other ways.
For example, the property of causing wetting is insufficient, or the thermal conductivity is poor.

The present invention provides an improvement in the method of depositing molten metal onto the surface of a rapidly moving cooling body to produce metal strip directly from the melt.

The improvement provides that the molten metal is made of a metal selected from the group consisting of copper, silver, molybdenum, and alloys thereof, and that the molten metal is 0.002 to 0.15 millimeters (m
u) and has a surface coating of chromium with a thickness of 0.25
˜3 micrometers (μm) surface roughness on the surface of the cooling body.

The present invention further provides that the molten metal is deposited on the surface of a rapidly moving cooling body so that a thin flat plate (
thin metal sections such as splats and strips
It also provides improvements in equipment for making.

The apparatus includes a cooling body having a surface suitable for receiving and applying molten metal to be deposited to effect rapid quenching, and is operatively coupled thereto.

It has means for depositing molten metal onto the surface.

The improvement in this device is that it is composed of a metal selected from the group consisting of copper, silver, molybdenum, and alloys thereof, and has a metal content of 0.002 to 0.00. The object of the present invention is to provide a cooling body having a surface coating of chromium with a thickness of 15 mm) and a surface roughness of 0.25 to 3 micrometers (μm).

Cooling bodies composed of copper, silver, molybdenum or their alloys are defined as metals that are used as the heat-extracting components of the cooling body, or ``heatsinks'', i.e., absorbing the heat of the molten metal. to cause its rapid quenching and solidification thereof, preferably at a rate considered necessary to form a metallic glass body from a glass-forming alloy melt, i.e. from 104 to 106
This means that it constitutes a member that causes quenching of molten metal at a speed of 0 K/sec or more.

This does not therefore mean that other metals cannot be used in the construction of the cooling body, even for structural purposes such as reinforcement.

Therefore, cooling bodies containing other metals may also be within the scope of the present invention.

The inventors have unexpectedly discovered that the above-mentioned chromium surface coating has a specific thickness and a defined surface structure (surface roughness).
Wetting easily occurs with nickel and/or cobalt-based alloys.

These metals form an amorphous structure (metallic glass) when rapidly quenched from the melt.

Particularly good wetting appears to occur when glass-forming iron-based boron-containing metal melts are used whose metal component consists primarily of iron.

These have extremely important commercial properties in practical terms.

This is because they have a pronounced soft magnetic property, which property makes them extremely suitable as materials for electromagnetic induction devices.

The specific chrome surface furthermore allows good adhesion of the fixed metal strip.

This property is essential for complete quenching of the metal if a ductile non-quality metal strip is desired.

Moreover, it also makes it possible to cleanly remove the solidified strip from the surface.

It is believed that the surprisingly improved soft magnetic properties of the iron-based, boron-containing metallic glass quenched on the cooling body of the present invention are due to the sufficient adhesion and complete quenching as described above.

Finally, the particular chromium-coated coolant of the present invention combines the advantageous wetting and quenching properties described above with excellent wear resistance.
It is something that is completely integrated.

Using a cooling body as described above with a chromium surface having a specific thickness and surface structure in a method for making metal slips directly from metal by depositing molten metal on the fast-moving surfaces of the cooling body. The benefits of cooling are obtained regardless of the shape of the cooling body.

That is, the cooling body may be a drum rotating at high speed, the outer surface of which is used as a cooling surface; or a cylinder rotating at high speed, whose inner surface provides a cooling surface. However, it may be a moving belt, or may be cup-shaped or any other arbitrary shape.

Additionally, any means for depositing molten metal on the cooling surface, such as jetting, flowing, drag, etc.
ging), dip-ing, and other methods may be employed without limitation.

For purposes of the present invention, a strip is an elongated article whose width dimension is much smaller than its length dimension.

The slip is a ribbon, sheet, or wire, and its cross section may be regular or irregular.

The attached drawings serve to explain the invention in more detail.

FIG. 1 is a cross-sectional view of an annular cooling roll whose outer surface is coated with chromium according to the invention.

FIG. 2 is a cross-sectional view of an annular cooling roll with a chromium-coated molybdenum ring embedded in its surface.

FIG. 3 is a cross-sectional view of a cylindrical cooling body with a chromium-coated cooling surface on the inside inclined with respect to the axis of rotation.

FIG. 4 is a partial cross-sectional side view of an apparatus for spraying molten metal onto a rotary chill roll and a rotary chill roll having a chrome-coated cooling surface.

FIG. 5 is a somewhat simplified perspective view of an apparatus comprising means for depositing molten metal onto a cooling surface in the form of a running endless belt having a chrome surface.

A heat-absorbing member (cooling body) that moves molten metal at high speed.
The chill-casting process is well known for producing non-vitreous (vitreous) as well as polycrystalline metal strips by depositing them onto a cooled surface.

As a cooling body for use in such a chill-caste method, a heat-absorbing member made of silver, copper, molybdenum, or an alloy thereof and having a chromium-covered cooling surface with a very special structure is used. It has now been found that a cooling body having very desirable properties, particularly for casting metallic glass strips of boron-containing iron-based alloys.

The chrome coating must be at least 0.002 mm thick.

Otherwise, there will be little or no benefit.

In particular, the wear resistance is not sufficient.

On the one hand, it must not be thicker than 0.157W7X.

Making the chromium coating substantially thicker than that results in insufficient quenching of the melt and the physical properties of the vitreous metal strip cast thereon are generally impaired, particularly with a loss of ductile and magnetic properties; For example, a decrease in maximum induction value and magnetic permeability is observed.

That is, 0.01 to 0.1 fight, more preferably 0.0
Good results are obtained with a chromium coating having a thickness of 1 to 0.075 mm.

The second critical element is the surface structure of the chrome coating.

As previously believed by those skilled in the art of metallic glass casting, it has been difficult or impossible to cast metallic glass strips by quench casting techniques onto chrome surfaces.

The main reason for this is that their thermal conductivity is relatively low.

It is not a scale, and such a strip, when casted on a smooth chrome surface, even if it is a smooth, thin chrome surface of thickness within the range contemplated by this invention, It was also found that it was not possible to wet the surface sufficiently, nor was it possible to adhere to the surface sufficiently to obtain good quenching of the strip.

As a result, strips cast on smooth chrome surfaces tend to be brittle, non-homogeneous, and lack good magnetic properties.

Such strips have no commercial value.

The inventors have hereby demonstrated that a thin chromium coating with a very specific surface structure overcomes the above-mentioned disadvantages and instead reduces the high-level transfer from the melt deposited on the cooling surface to the underlying heat sink. heat transfer, resulting in rapid solidification of the melt, and a high degree of adhesion of the solidified strip to the cooling surface, resulting in complete and rapid quenching of the metal ST-IJ tube below the crystallization temperature. It has been unexpectedly found that this results in a strip with good magnetic and physical properties.

To achieve these desired results, the surface roughness should be approximately 0.
．． It must be between 25 and 3.0 μm (micrometers).

Inadequate surface roughness below about 0.25 μm results in the drawbacks of smooth chrome surfaces as described above.

If the surface roughness is larger than about 3.0 μm,
Although generally sufficient quench rate and sufficient adhesion are provided,
A strip with an unnecessarily high degree of roughness forms on the surface casted in contact with the cooling surface.

Good results are obtained if a cooling surface structure corresponding to a surface roughness of 0.5-2.0 μm (micrometers) is employed.

The most preferable surface structure is a so-called "matte finish," but it is also necessary that the surface roughness be within the above-mentioned range.

Here, "matte finish" means a visibly distinguishable ray (
It is defined as a surface structure without a layer.

In other words, the surface roughness is the same no matter which direction it is measured.

However, although a satin finish gives the best results, it is not absolutely required.

Acceptable results are obtained under conditions where there are discernible rays, ie, where the finish is directional in the longitudinal direction of the casting, or perpendicular thereto, or anywhere in between.

An example is U.S. Pat. No. 4,077,4 to Bede et al.
No. 62, or U.S. Patent No. 3,85 to Kavesh.
As described in No. 6,074, when an amorphous metal slurry is made by injecting a molten glass-forming alloy onto a rapidly rotating cooling surface, the cooling body The surface of the heat sink gradually erodes, resulting in a rough, uneven track around the periphery of the coolant surface where the wax strip carving takes place.

Further cursing on the same 1-rack results in an unacceptable quality of 1-slip with a rough surface and jagged edges.

The problem of cooling surface wear in these methods is even more acute when carstaing is performed under vacuum.

In vacuum casting, due to the absence of an intervening gas layer,
A larger area of the cooling surface is impacted by the melt jet 1 and subjected to wetting.

Another factor that leads to significant wear on conventional cooling surfaces is that the alloys being cast contain significant amounts of refractory metals such as molybdenum, tungsten, chromium, hafnium, iridium, nioff, osmium, platinum, rhenium, It is mixed with rhodium, ruthenium, cucumber, thorium, vanadium, and zirconium.

Accordingly, the use of the cooling surfaces of the present invention is useful when casting is carried out under vacuum (e.g., under an absolute pressure of less than about 257,117 MHg) or when castings are carried out under vacuum (e.g., under absolute pressures less than about 257,117 MHg) or when casting When casting alloys,
and especially when such alloys are cast under vacuum.

For the purposes of the present invention, there is no criticality as to the form of the cooling body and the mode of casting operation.

An example is Bedel I et al. and Kavesh mentioned above.
It can also be cast by injecting molten metal onto the outer circumferential surface of a rapidly rotating drum, as disclosed in U.S. Patent No. 3,5 to King.
2 2, 8 3 Casting on the outer surface of a rotating drum by pulling the metal out of a meniscus formed in the slotted nozzle, as described in No. or similar pull-out castings, as described in U.S. Pat. No. 3,8 to Maringer et al.
It is also possible, as described in US Pat. No. 96,203, to draw the casting surface from a suspended, unrestricted droplet of molten metal.

An alternative method is to immerse the outer circumferential surface of a rotating cooling drum in a bath of molten metal, as described in U.S. Pat. No. 3,861,/I50 to Mobley et al. Alternatively, the molten metal may be passed through a slot under pressure, as described in U.S. Pat. No. 4,142,571 to Narasimhan. It can also be done by applying it to the cooling surface from a nozzle shaped like 1.

Additionally, US Patent 3,8 8 1 to i(avesl+
, 540 and U.S. Pat. No. 3,88 to Polk et al.
], 542, or Pond
Trans,Met by Maddin
, Soc, AIMB, 245 (1969)2
, 475-6, the inner surface of the rotating cylinder can be used as a cooling surface.

Furthermore, the analogy is U.S. Pat. No. 3,888 to Bedell.
1. , 5 4 As described in No. 1, and H
．． C. Chem and C. E. Mi ] l
Rev. er. Sci. lrnstrum,
41, 1237 (1970), casting can also be carried out into a nip formed between two counter-rotating cooling rolls.

Additionally, cooling may be provided by an open concave surface of a cup rotating at high speed, as disclosed in US Pat. No. 2,825,108 to Pond.

Alternatively, U.S. Pat. No. 2,886, to Wade,
The cooling surface can also be provided by a running belt, preferably a running endless belt, as described in No. 8 6 6.

The disclosures of the patents and publications mentioned above are incorporated herein by reference.

The benefits of using the special chromium-coated coolant of the present invention are realized regardless of the structure of the coolant and regardless of the means of depositing molten metal onto the cooled surface, i.e. by jet, meniscus or suspended droplet. The benefits may be obtained whether by dragging from the surface, extruding through a slotted nozzle in close proximity to the cooling surface, or by immersion in a bath of molten metal, or by any other suitable means. It will be done.

The chromium coating or plating can suitably be applied by electroplating methods to the surface of substrates made of copper, silver, molybdenum or alloys thereof by conventional electroplating methods.

However, other methods can be adopted if necessary.

The method of chrome plating is well known and generally involves the following operations.

That is, a suitable plating bath, for example containing chromic acid,
This is done by passing a direct current through the plating bath accompanied by sulfate ions, typically provided by sulfuric acid, and using the surface to be plated as the cathode.

The surface to be plated is first coated with a thin (e.g. o
．． Applying a strike coat of nickel (with a thickness of less than 100 mm) facilitates the chrome plating operation and improves the adhesion of the chromium coating.

This is a common practice when performing chrome plating.

The surface structure, that is, the above-mentioned surface roughness, can be achieved by treating the cooling surface by an appropriate method using an appropriate abrasive before or after applying chrome plating, or both before and after applying chrome plating. Surface roughness can be obtained.

For ease of processing and the degree of bonding of the chromium coating (i
It is preferable to perform a surface treatment before applying chrome plating in order to protect the material.

A suitable surface structure can be obtained by polishing the cooling surface with a suitable abrasive such as emery cloth.

Alternatively, a similar objective can be achieved by impinging a suitable finely divided hard powder on the cooling surface, or by other similar means.

One very effective method is the ``slurry honing'' method, which involves impinging the surface to be roughened with a fluid stream containing finely divided suspended abrasive particles.

In any case, the methods of plating and of providing a particular surface structure are known per se and do not form part of the present invention.

When the cooling body is to be made of molybdenum, the methods normally employed for the secondary processing of molybdenum, i.e. machining from solid slabs, such as cast pieces, etc.
Alternatively, it can be produced by a method including secondary processing using a known powder metallurgy method.

A particularly preferred embodiment of the invention is a composite cooling body, particularly a copper cooling roll provided with molybdenum hoops as shown in FIGS. 1 and 2.

The casting surface provided by molybdenum is chrome plated.

It has a surface structure as described above.

Referring to FIG. 1, a cooling roll 1 made of copper is mounted so as to be rotatable around a rotating shaft 2. As shown in FIG.

The outer surface of the cooling roll 1 is provided with molybdenum hoops 3.

In the case of FIG. 1, molybdenum hoops cover the entire outer peripheral surface of the cooling roll.

The molybdenum hoop may be attached to the copper cooling roll by, for example, a shrink fit.

Another method, for example, is the oxyacetylene spray method, where a molybdenum wire is placed in a cone of an oxygen/acetylene flame to melt the metal and then direct the molten metal onto the surface to be coated. The molybdenum surface can be created by any other conventional surface application method, such as a method involving spraying in droplet form.

Other suitable methods include the plasma arc spray method and the Kratzdeng method.

Another embodiment of the invention using a copper-beam coolant made from a conventional copper-beam alloy is also suitable.

The detailed design and construction of the apparatus of the present invention is within the ability of any person skilled in the relevant art.

The following examples further illustrate the invention and represent the best mode currently contemplated for its practical application.

Examples and Comparative Tests The equipment employed is similar to that shown in Figure 4, and employs water-cooled copper cooling rolls.
The roll has a matte finish chrome coating with a thickness of 0.025 mm, and its surface roughness is approximately 0.76 to 0.8.
0 μm (approximately 30-34 μinch).

The cooling roll diameter is 38. ICrrL (15 inches), which is 914~JO67m/min (3000~3
It rotated at a speed that gave a circumferential speed of 500 ft/min).

The nozzle for depositing molten metal is 2.54 cr long.
IL (1 inch) and width 0.57ff7K (20 mil)
It had an orifice.

The gap between the cooling surface and the nozzle is approximately 0. 2 5 vr
t (approximately 10 mils).

The composition Fe8B+3.5 8i 3.5' C2 (
atomic%) alloy is extruded from the nozzle, approximately 4.53 kg
contact with a rotating cooling surface under pressure at a rate of 10 lbs/min (10 lbsZ min).

It solidifies on the surface of the cooling roll and rlJ2.5 4
cm (1 inch) and thickness approx. 0 3 8
It became a slip of crrL (1..5 mil).

A comparative test was conducted employing a copper chill roll without the chromium coating described above, but under otherwise identical conditions as described above.

The properties of the strips obtained in the above examples and comparative tests are summarized in Table 1 below.

The chrome-coated chill roll showed no discernible wear even after 1.10 kg of metal was cast twelve times in a row, each time on the same "track" and approximately the same dimensions.

If a plain copper wheel without coating is used, considerable wear is observed even after only one casting, and therefore after each casting the cooling surface must be repaired to produce a strip with acceptable surface properties. In order to achieve the degree of smoothness necessary to create a ``dressing'', it was necessary to perform ``dressing''.

As the data in Table 1 above shows, casted steel IJ on a chrome plated surface with a specific surface structure
The strips have substantially improved magnetic properties compared to strips conventionally cast onto a copper cooling surface.

In each case, the differences in magnetic properties from the beginning to the end of the experiment are substantially low.

Transformers made from such cast IJ strips on chrome-plated cooling surfaces have greatly reduced core losses and their VA demands have also been greatly reduced. wax, it would have substantially improved efficiency.

Since the invention is susceptible to various modifications and improvements without departing from its scope and essential characteristics, everything in the above description is to be construed as illustrative only; The scope of the invention should be defined only by the claims.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a cooling roll of the present invention whose outer surface is coated with chromium. FIG. 2 is a cross-sectional view of an annular cooling roll of the present invention having chromium-coated molybdenum links embedded in its surface. FIG. 3 is a cross-sectional view of a cylindrical cooling body of the present invention having a chromium-coated cooling surface on the inner surface inclined with respect to the rotation axis. FIG. 4 is a side view of an apparatus for spray coating a rotary chill roll with molten metal and a partial cross-sectional view of the rotary chill roll having a chrome coated cooling surface. Figure 5 shows a running endless motor vehicle with a chrome-coated surface.
1 is a perspective view of an apparatus including means for depositing molten metal onto a belt-shaped cooling surface; FIG. Reference numbers in the figures represent the following, respectively. 1... Cooling roll, 2... Rotating shaft, 3
...Surface coating.

Claims (1)

[Scope of Claims] 1. A method for producing IJ tubes directly from a molten body by depositing the molten metal on the surface of a cooling body moving at high speed, the method comprising copper, silver, molybdenum, and alloys thereof. has a heat-absorbing metal selected from the group, and 0.0
Depositing molten metal on the surface of a cooling body having a surface coating of chromium with a thickness of 0.2 to 0.15 millimeters (m1rL) and a surface roughness of 0.25 to 3.0 micrometers (μm). The method for manufacturing the metal strike IJ tube. 2. The method according to claim 1, wherein the cooling body is a cooling roll capable of rotating at high speed, and the outer surface thereof is used as the cooling surface. 3. The method according to claim 1, wherein the cooling body is a cylinder capable of rotating at high speed, the inner surface of which is used as a cooling surface. 4. A method according to claim 1, characterized in that the cooling body is an endless belt capable of high speed movement. 5. The method according to claim 1, wherein the cooling body is a cup-shaped cooling body or any other arbitrary shape that can move at high speed. 6. The cooling body is a cooling roll, the molten metal is deposited on the peripheral surface thereof, and the metal is a metal that forms an amorphous (glassy) object when rapidly quenched from the melt. A method according to claim 1, characterized in that: 7. The method according to any one of claims 1 to 6, characterized in that the cooling body is composed of a copper-bery17ium alloy or molybdenum. 8. A method according to any one of claims 1 to 7, characterized in that the surface coating has a satin finish without discernible lays.