NO811584L - QUICK CASTED ALLOY BAND WITH DIFFERENT PARTS. - Google Patents

Description

The present invention relates to a new and improved metal band material, and more specifically to a quick-cast metal band with different longitudinal sections which are metallurgically bonded to each other during the casting of the band. The invention also relates to a method and apparatus for producing such tape.

The invention is directed to tape materials, both amorphous, crystalline or combinations thereof, with different parts.

In a preferred embodiment, the invention relates to metal alloys in band form in which at least a part of this is amorphous. In the present description, the term "amorphous" means a composition in which at least 50% is amorphous, which is normally measured by X-ray diffraction.

From the early 1900s it has been published, such as in US Patents Nos. 905,758 and 993,904, that metal strip material could be produced continuously by discharging molten metal onto a moving cooling surface. More recent works such as US Patent No. 4,142,571 indicate specific refinements in the strip casting die structure to aid the production of strip material. Also, various publications including US Patent No. 3-856,513 describe preferred alloys, especially for the manufacture of amorphous ribbon and wire material.

For certain applications it has been found advantageous to join at least 2 pieces of the tape material along their longitudinal axis. Such joining can be used to obtain a band with a greater overall width, or can be used to join different parts. Common techniques for joining several bands are welding, brazing and brazing. Certain factors, however, such as heat and especially heat gradients occurring during welding, brazing and brazing can adversely affect the quality of such an assembly or the quality of the multiplex tape material.

As previously mentioned, a preferred embodiment of the present invention relates to strip material in which at least one deviating part is amorphous. Amorphous metal alloys are those which are produced by a method in which crystallization is avoided, normally by extremely rapid cooling of the metal from the liquid state. Such a cooling rate is usually of the order of at least approx. 10 4oC per sec.. Because of their atomic arrangement and composition, some amorphous alloys can have enhanced properties such as higher strength and increased resistance to chemical attack compared to conventional crystalline alloys. Therefore, such amorphous alloys may be ideally suited for applications such as, but not limited to, razor blade edge materials, due to their strength, hardness, tensile properties, and corrosion resistance. Certain amorphous materials are also known to have enhanced magnetic and electrical properties and the tape of the present invention may be desired for electrical applications. ■■

The present invention also relates to quick-cast crystalline materials which have several areas of application. The present invention further comprises combinations of different crystalline materials, different amorphous materials and combinations thereof where it is desirable to use such different materials in order to reduce the total costs of the composite material, or multiplex tape, or to

locate desired properties, dimensions, etc. of different materials in a composite band. For example, the present invention can be used to produce delicate materials by simultaneously producing edge parts of a more robust material, which would facilitate the handling of the delicate material. After manufacture, the handling parts could be easily trimmed from the tape. Also, this invention could be used to join alloys having different thermal electrical properties suitable for use in

manufacturing of thermocouples or multiple thermocouples. In addition, the present invention can be used to cast strips of different dimensions through their width for the purpose of varying mechanical strength, electrical properties, etc. through the strip's cross-section. Furthermore, the invention can be used to produce bands with alloys of different expansion characteristics through the cross-section thereof. So-

led, by heating such a band, an intended curvilinear band configuration can be achieved. The tape according to the invention can be used in several ways, and the above-mentioned examples are only to illustrate this and should not be understood as any limitation of the scope of the present invention.

Consequently, a new and improved multiplex tape material is desired in which various parts are composed in a way that does not adversely affect either the overall quality of such individual tape components or the entirety of each such tape. Likewise, a new and improved method and apparatus for the production of such band components and multiplex combinations is desired. The present invention can be summarized as providing a new and improved

■quick, cooled cast metal strip comprising several different parts where each part is metallurgically alloyed during casting to adjacent parts along the length of the strip. In the method and apparatus for producing such a strip, a stream of molten metal is delivered to a casting surface from a first crucible and at least one further disparate stream of molten metal is delivered to the casting surface such that an outer edge of the disparate stream contacts it the outer edge part of the adjacent dissimilar material forming a metallurgical alloy bond between them during casting.

Among the advantages of the present invention is the possibility of combining several different parts into a composite band material with a metallurgical alloy bond between adjacent different parts that is formed during the casting of such band material without adversely affecting the quality or properties of the individual band parts.

One purpose of the present invention is to provide a strip of quick-cast strip material with at least 2 different parts which are metallurgically alloyed along the length of the strip and thereby form a multiplex strip or composite strip which has different properties, structure or quality in each part of the strip.

Another advantage of the present invention is the provision of a method and an apparatus for rapid casting of strip material consisting of various parts which are metallurgically alloyed to each other along the length of the strip during the casting operations without adversely affecting the quality or properties of the strip material.

A further advantage of the present invention is that where. strength, corrosion resistance and other properties are only required at an edge or the edges of the strip material, the expensive alloy components such as cobalt and molybdenum are only needed and used at such edge portions of a multiplex strip material, which reduces the cost of the strip.

Another object of the present invention is to provide a band of metallurgically alloy bonded amorphous and crystalline parts without causing the amorphous part to crystallize during the bonding thereof. Another purpose is to provide a band of components joined in a transition zone where an alloy formed in the transition zone has enhanced properties compared to those in the parts joined together.

These and other objects and advantages will appear more clearly upon reference to the following detailed description and accompanying drawings. Figure 1 is a cross-section from the front of an apparatus according to the present invention. Figure 2 is an enlarged cross-section of the nozzle area of the apparatus shown in fig. 1. Figure 3 is a partial perspective illustrating an alternative apparatus according to the present invention. Figure 4 is a perspective view of the casting surface and the strip cast thereon from an apparatus shown in fig. 3. Figure 5 shows from above an alternative device according to the present invention. Figure 6 shows in perspective an alternative device according to the present invention. Figure 7 is a cross-section of a preferred crucible and nozzle according to the present invention. Figure 8 is a curve of an energy distribution X-ray analysis for the element nickel taken across the band in the example. Figure 9 is a curve of an energy distribution X-ray analysis for the element silicon taken across the band in the example. Figure 10 is a curve of the Knoop hardness at a load of 200 g taken across the belt in the example.

In the drawings, fig. 1 and 2 a preferred apparatus according to the invention. As shown in fig. 1, this apparatus includes a first crucible 10 with an internal cavity designed to receive and contain molten metal. The first crucible 10 also contains a nozzle 10a through which a first stream of molten metal is emitted from the cavity to a casting surface 18. In a preferred embodiment, the continuous strip material 30 is cast on a relatively smooth outer surface 18 of a circular drum or wheel 13. Other configurations other than this circular can be used, e.g. the band according to the present invention can be cast on a moving belt as shown in fig. 6, on the inner surface of a drum between a pair of opposing rollers, in a coolant or the like.

In a preferred embodiment, the casting element 13 consists

of a water-cooled precipitation-hardened copper alloy wheel of approx. 90% cups. Copper and copper alloys are selected on

due to its high thermal conductivity and wear resistance, but also steel, brass, aluminium, aluminum alloy or other materials can be used alone, or multi-part

wheels with sleeves made of molybdenum or other materials can also be used. Likewise, cooling can be accomplished using a medium other than water, water being chosen because of its low cost and easy availability.

During operation of the strip casting apparatus according to the present invention, the outer surface 18 of the casting wheel 13 must be able to absorb the heat produced by contact between molten metal at the initial casting point, and this heat must be mainly conducted into the copper wheel during each revolution of. the wheel. Removal of this heat can e.g. is carried out by passing a sufficient amount of water through internal channels which are located close to the surface of the casting wheel 13. Optionally, the coolant can be passed to the underside of the casting surface. Of course, refrigerator techniques and the like can be used to adjust and optimize cooling rates, e.g. to effect wheel expansion or contraction during strip casting.

Whether a drum, wheel or belt is used for casting, the casting surface 18 should generally be smooth and symmetrical to maximize the evenness of the belt casting. For example, in certain strip casting operations where it is desired to cast a uniformly sized strip, the distance between the outer casting surface 18 and the surfaces that delimit the opening or the nozzle 10a or the lia that supplies molten metal to the casting surface 18 should not deviate particularly from a desired or fixed distance. In the following, this distance shall be called the standoff distance or gap. The gap at each nozzle should normally be kept substantially constant during the casting operation when it is the operator's intention to cast uniformly sized strip portions from this nozzle. If, however, controlled variations in thickness are desired either in the finished composition or in certain composite bands of the composition, a programmed standoff distance both for the entire nozzle component assembly and/or for each contributing nozzle may be used.

If the casting element is a drum or a wheel, the element should be accurately constructed so that it does not come out of the path during the operation to ensure smooth strip casting. Consequently, it has been found that a drum or a wheel that deviates from the track by approx. 0.5 mm or more may have an order of dimensional instability which, unless corrected or compensated during operation, may be unacceptable for certain strip casting operations. It has been found that acceptable dimensional symmetry can be achieved by fabricating a wheel or drum

from a single complete piece of cold-rolled or forged copper. As mentioned above, however, alternative materials can be used.

The molten materials to be cast in the apparatus described here are preferably kept in a crucible or funnel which is equipped with a corresponding nozzle. The nozzle is often, but not necessarily, placed in a lower part of the crucible as shown in the drawings. The nozzle may be an integral part of the crucible or may consist of separate materials which are fixed in the crucible.

The crucible is designed to receive and contain molten metal. Proper materials must be used for the crucible to withstand molten metal conditions, and where the crucible does not have a monolithic structure, the joints and seams between separate parts of the crucible must be constructed so that molten metal is prevented from leaking out during sustained operation.

A preferred crucible 10 for continuous production of quick cast strip material is illustrated in detail in fig.

7. The part of the crucible 10 that holds the molten material

the metal which is formed between the inner surfaces can have different shapes. In a preferred embodiment, however, an upper part of the crucible 10 has a significantly larger cross-sectional volume than the nozzle area of the crucible 10 in order for molten metal head height above the mouth. the piece 10a is essentially unaffected by minor variations in molten metal volume in the crucible 10. Such

structure helps to maintain a mainly

constant metallostatic pressure head at the nozzle, even with small variations in the metal volume that may occur in the crucible 10 during sustained or continuous casting operations. The casting can also be carried out under externally attached pressure equipment which could be controlled directly.

As shown in fig. 7, it is preferred that the inner walls of the crucible 10 converge not on each other in the direction of the nozzle 10a, and that such inner walls are curved, rounded or generally curvilinear at places with bends or bends in the crucible 10 in order to minimize metal turbulence in it during a casting operation .

The area which contains molten metal and is formed between the inner walls of the crucible 10 which is shown in fig. 7 should be enclosed such as with side walls. It is pointed out that the width of the crucible nozzle according to the present invention should not be limited. It has been found

that a crucible 10 and the nozzle 10a according to the present invention can be constructed by first cutting or chiseling out ceramic plates such as insulating plates made of kaolin fibers to the desired shape as shown in fig. 7. Which

any number of these plates 42 can be stacked on top of each other to give the desired crucible 10 and nozzle 10a width. There is not expected to be a limitation of the maximum width of the crucible and nozzle according to the present invention, and widths beyond 90 cm for strip parts from a crucible are covered by the present invention. After the required number of plates are stacked, the interior walls may be ground or otherwise treated to provide generally smooth interior walls over the entire width of the stacked elements forming the crucible 10. Also, one piece materials may be used to make a monolithic crucible where stacking will not be necessary. After the chiseled plates are stacked, the stack can be placed between non-chiseled plates, which can serve as side walls for the crucible 10.

To hold the stacked plates included the side walls

in position, it has been found expedient to place a metal plate against the outer surface of each side wall and bolt the plates together in a suitable number of places around the crucible, thereby compressing the crucible assembly tightly. With such a device, a minimal amount of molten metal tends to flow into the seams between the plates, but the compression of the device causes the metal to solidify and stop the flow before it adversely affects the crucible or the strip casting operation. The crucible in the present invention can be assembled with ceramic cements or the like, or can be constructed from a monolithic structure that does not require assembly.

As mentioned, a nozzle is located in each crucible, preferably in their lower part. The nozzle contains a passage opening which is defined between the inner walls of the crucible. In a preferred embodiment as shown in fig. 7, the nozzle 10a is formed between a crucible wall and an inner surface of an insert 50. A part of the inner surface of the insert 50 is preferably placed against a part of an edge formed by an outer surface of the crucible 10. The structure of such preferred crucible is more fully described in co-pending US Application No. 148,440 dated May 9, 1980 entitled "Apparatus for Strip Casting" by the same applicant.

The insert 50 described in a preferred crucible

in the present invention can be easily replaced although it is preferred that the inserts 50 and the crucible be reused, either together or separately. Damage to an insert 50 should not render the entire crucible unusable. In case of such damage to the insert, the insert 50 is simply replaced and the process can continue.

In a preferred embodiment which is shown in cross-section in fig. 7, the insert 50 is provided with a front edge surface 70. In this embodiment, the front edge surface 70 faces the casting surface 18 and is located within less than 3 mm of the casting surface 18. Preferably, the front edge surface 70 is located within 2 mm and in a more strongly preferred embodiment within 0.5 mm of the casting surface 18. It is also preferred that the front edge surface 70 in such an embodiment is mainly parallel to the casting surface 18 which is movable below it.

This parallelism between the casting surface 18 and the insert 50 can be achieved by placing a sheet of sandpaper or the like against the casting surface 18 with the grainy side of the sandpaper towards the insert 50. By moving the insert 50 into close contact with the casting surface 18 with the sandpaper placed between them and moving the casting surface and the sandpaper simultaneously past the insert 50, the front edge surface 70 of the grain side of the sandpaper is sanded to substantially complete parallelism with the casting surface 18. Such substantially complete parallelism can be achieved even when rounded or other curvilinear casting surfaces are used. To achieve such parallelism by this method, 400 or 600-grit sandpaper has been found suitable. Other faces of the crucible can be brought to substantially complete parallelism by this same method.

By keeping the leading edge surface 70 in substantially complete parallelism with the casting surface 18, the standoff distance or gap between the leading edge surface 70 and the casting surface 18 is maintained over its entire length. It has been found that the gap between the front edge surface 70 and the casting surface 18 should be kept at less than approx. 3 mm to cast the tape material successfully. Preferably, this gap is kept at less than approx. 2 mm and for casting certain alloys into thin-dimensioned bands, gaps of less than 0.5 mm are preferred. Alternatively, the corners of the insert 50 may come to a point at the front edge 70 with a 90° joint of the front edge of the insert 50 as opposed to a defined surface length as discussed above.

With regard to the bottom surface of the nozzle 10a, it is preferred that this surface is placed as close as possible to the casting surface 18 without causing any disturbance to the casting surface which is movable below it. Consequently, this face of the nozzle may barely clear the casting surface 18, i.e. perhaps within approx. 0.05 mm. Such a distance must not be so great that appreciable molten metal can flow back here during casting. Precautions can be taken for the edge parts of the strip material which may have to pass under a portion of another downstream crucible.

The melting crucibles 10 or 11 are preferably made of one material with very good insulating properties. If the insulating ability is not sufficient to keep the molten metal at a relatively constant temperature, auxiliary heating means such as induction coils 12 may have to be arranged in and/or around the crucibles 10 and/or 11, or resistance elements such as wires may be arranged. A suitable material for crucibles is an insulating sheet made of kaolin fibers, a naturally occurring very pure alumina-silica fired clay. Such insulation material can be purchased under the trade name Kaowool HS plates. For continuous operations and for casting alloys that melt at higher temperatures, various other materials may have to be used to construct the crucible or crucible nozzle such as silica gel, alumina, graphite, alumina-graphite, clay graphite, burnt clay, quartz, boron nitride, silicon nitride, boron carbide, silicon carbide, zirconium oxide, stabilized zirconium oxide silicate, magnesium oxide, chromium-magnesite and various combinations or mixtures of such materials.

Although other materials are covered by the present invention, the insert 50 which forms part of the nozzle of the crucible is preferably constructed of boron nitride, silicon nitride, silicon carbide, boron carbide, zirconium oxide or quartz.

It is required that the passage opening of the nozzle 1.0a or 1a remains open and its shape remains substantially stable during the strip casting operation. It is clear that the die pieces should not erode or clog particularly during a multiplex strip casting sequence or certain purposes such as maintaining uniformity during the casting operation and minimizing metal flow turbulence in the crucibles may be defeated. Thus, it is clear that certain insulating materials are not able to maintain their dimensional stability over long casting periods. To avoid this problem, the nozzle 10a or 11a, especially the part defined by the insert 50, can be constructed of a material that can better maintain dimensional stability and integrity during exposure to high temperatures of molten metal over extended periods of time.

The drive system and container for the drum, wheel or other casting surface 16 of the present invention should be rigidly constructed to allow rotation of the drum without structural instability which could cause the drum to slide or vibrate. In particular, care must be taken to avoid resonant frequencies at the operating speeds of the drum. The casting surface 18 should be able to move at a surface speed of approx. 60 linear surface meters per my. to more than approx. 3,000 linear surface meters per min.. When a drum is used with a circumference of approx. 2.4 m, this speed corresponds to a drum speed of approx. 25 revolutions per my. to approx. 1250 revolutions per min.. A three horsepower reversible, dynamically braked motor with variable speed provides an adequate drive system for an integral copper casting drum with 5 to 25 cm thickness and approx. 2.4 m circumference. The energy requirement may have to be modified depending on the type and size of the casting surface 18 used. The casting surface 18 can be moved in an opposite direction to that shown in the drawing, and the crucible can be placed in any location

around a circular casting wheel.

In one embodiment, the cast surface 18 of the wheel or drum in the apparatus according to the present invention is smooth. It has been found that for certain applications such as the manufacture

of amorphous strip parts, treatment of the outer surface 18 of a casting wheel 13 with 400 grit paper and preferably with

600 grit paper give a product with better uniformity.

In an exemplary operation of the device according to the present invention as shown in fig. 1 or 3, molten metal is delivered to a first heated crucible 10 and to a second crucible 11, although such metal delivery can take place

sequentially rather than simultaneously. A heating device such as an induction coil with resistance wire 12 can be arranged in and above the crucibles 10 and 11 to provide or maintain relatively constant molten metal temperatures as desired. During operation of the apparatus according to the present invention, metal can be poured directly into pre-heated crucibles. Such metal preheating temperatures<:>and heating of the crucibles with auxiliary devices should prevent solidification or plugging of the nozzle during the beginning of the casting operation, and the temperature of the liquid metal should then maintain each crucible at a sufficient temperature to ensure uninterrupted molten metal flow through each nozzle. For certain applications, the nozzle should be heated from the outside during the casting operation. Also, the metal fed to the crucibles can be superheated to allow a certain temperature loss without adversely affecting the metal flow.

In one embodiment, a metallostatic head height in the crucibles should be maintained at a relatively constant level during the casting operation to ensure that a relatively constant static head pressure is maintained at the nozzle. This can be achieved by first pouring molten metal into each crucible up to the desired height and then controlling the rate at which additional molten metal is poured into that crucible to maintain the metallostatic head. The rate at which additional molten metal is supplied to the crucible should be substantially consistent with the rate at which metal flows from the nozzle onto the casting surface 18 to form the multiplex band material of the present invention. Maintaining a relatively constant height of metal in the crucibles guarantees that the molten metal flow pressure through the respective nozzle is maintained relatively constant so that it does not adversely affect the casting operation or the quality of the strip material. As mentioned above, externally applied pressure can alternatively be used to control the pressure at the nozzles.

In the present invention, a rapidly cooled metal band 30 is cast on the casting surface 18. Such band material 30 consists of several different parts such as parts a, b, c and d in fig. 5 or parts a^, b, and a^ in fig. 6. Each individual portion of the band 30 is metallurgically alloy bonded to the edges of the adjacent portions along the entire length of the band. Furthermore, such metallurgical alloy bonding acts as an integral part of the strip casting operation.

The tape 30 with several different parts is called "multiplex tape" or "composite tape" in the present application. The multiplex tape 30 in the present invention is intended to comprise a tape with at least two different materials metallurgically alloyed together along the length of the tape. This metallurgical alloy bond occurs during the casting operation that forms the band. "At least two different materials" preferably means two different compositions, but such an expression may also include a multiplex tape having the same composition but other properties that are different such as, but not limited to, electrical resistivity, permeability, conductivity, core loss characteristics, yield strength, hardness, atomic arrangement, dimension, corrosion resistance, thermal expansion, color and the like.

To illustrate this, a part of a multiplex band according to the present invention may have expansion characteristics that differ from an associated nearby part. Thus, by heating or cooling such tape, an intended curvilinear tape material can be obtained. The present invention can also be used to produce multiplex tapes with amorphous tape parts which are metallurgically alloyed to crystalline tape parts. When a band of amorphous material is joined by conventional means including heating such as welding to a band of crystalline material, the amorphous band becomes very brittle because the temperature to which it is exposed exceeds the crystallization temperature. In the present invention, on the other hand, the cooling rate is so fast that crystallization of the amorphous band portion is essentially avoided except possibly in the transition zone.

The rapid cooling of a ribbon casting operation can also be advantageous in the production of certain crystalline ribbon materials. Rapidly cooled crystalline alloys generally tend to develop a highly desirable microstructure that is finer than conventionally produced crystalline materials. Also quick-cast crystalline materials can contain desired alloy phases that are not found in conventional crystalline materials and consequently quick casting can avoid or prevent the formation of harmful alloy phases. In addition, rapid casting can produce new alloy phases in crystalline materials, which, even if they are metastable, generally have improved properties.

In a preferred embodiment, the present invention relates to the production of multiplex tape 30 with an amorphous alloy part which is formed with an adjacent metal or metal alloy part, which may or may not be amorphous, the latter part forming a unit with the former amorphous alloy part. In the present invention, the multiple strip portions can be cast simultaneously adjacent to each other on the casting surface 18 as shown in the embodiment illustrated in Figures 1 and 2. In this embodiment, the nozzles 10a and 1a both deposit a stream of molten metal 20 and 22, respectively approximately the same transverse line across the casting surface 18 adjacent to each other. As best shown in fig. 2 streams of molten metal run together to a joint and an actual alloying of the two converging streams really occurs at the interface which is also called the transition zone. The cooling rate is so fast during the casting of the metal band material that the oncoming streams do not have sufficient residence time to affect the entirety of the other metal stream outside the transition zone particularly adversely. Therefore, the composition, dimensions, hardness, strength, tensile strength, corrosion resistance and other properties of a part of the tape are not adversely affected by the contact between adjacent parts themselves

in the molten state.

Alternatively, the multiple band portion can be cast successively on the casting surface 18 as shown in the embodiments illustrated in Figures 3 and 4. In such an embodiment, a stream of molten metal is supplied from a crucible 10 to the casting surface 18. Another crucible 11 is located is downstream of the first crucible 10 in relation to the casting direction, which is illustrated by the arrow in fig. 3. The second crucible 11 has a nozzle lia which must be positioned so that an outer edge portion of the second stream of metal comes into contact with an outer edge portion of the first metal to provide a metallurgical alloy bond between them during casting. The first stream may be molten, partially solidified or also totally solidified when the second stream comes into contact with the outer edge. What is required in the casting operation is that a metallurgical alloy bond is formed between these as the multiplex band is formed.

Although the development has been discussed in terms of two streams of metal giving a duplex band, any number of different batches of alloy can be metallurgically bonded together in the present invention. E.g. illustrates fig. 5 a<0>multiplex strip composed of 4 parts a, b, c and d cast from 4 separate crucibles A, B, C and D. Also fig. 6 illustrates a triplex band which can be cast by placing 2 streams of metal from 2 separate nozzles in a common crucible A near both edge portions of a single band portion b, from hopper B giving a multiplex band with portions b and a metallurgically alloyed during casting.

In this embodiment, the 2 nozzles of the crucible A are preferably separated by a bridge with approximately the same width as the central band portion b.

During formation of the metallurgical alloy bond between adjacent non-uniform portions, such non-uniform band portions fuse with each other. The joint between adjacent dissimilar parts which is called the "transition zone" in the present invention passes through the bands from the upper surface to the lower surface in a direction which is essentially parallel to the longitudinal axis of the band. Although the transition zone is illustrated in broken lines in the drawing, it need not be easy to see such a transition zone by ordinary consideration.

A preferred embodiment according to the invention may relate to the production of razor blades. In such an embodiment, the composition of the metal in the first crucible 10 is preferably chosen so that an amorphous alloy is formed with strength properties, hardness, toughness and corrosion resistance which properties are generally desirable for forming the cutting edge portion of a razor blade. The composition of the metal in the second crucible 11 can be selected so that a suitable background material is obtained for the cutting edge portion of the strip.

EXAMPLE

A two-piece, or duplex, metal alloy band was formed

et according to the present invention by using 2 crucibles similar to what is illustrated in fig. 3. The casting surface consisted of a 3.8 cm outer surface of a 20 cm diameter copper wheel which was rotated at a speed of 32 m per revolution. Sec. with the axis of rotation mainly horizontal. In this example, the crucible located slightly downstream of the second crucible is called the "pre-str crucible". The first crucible 11 was made of silicon oxide and had a generally circular cross-section with an internal diameter of 10 mm tapering to a slotted nozzle with internal dimensions of 5 mm x 0.42 mm. The bottom surface of the nozzle was held approximately 0.43 mm above the casting surface, and the nozzle was positioned substantially parallel to the axis of the wheel. The first crucible 10 contained approx. 8.4 g of an alloy composition FeQ^Si^B]_2f calculated as atomic percentage. This alloy is called Alloy I in the following.

The second crucible 10, which was also made of silicon oxide, had a circular cross-section with an internal diameter of 10 mm which narrowed over 24 mm to a circular opening with an internal diameter of approx. 0.64 mm. The bottom surface of the nozzle was kept at approx. 0.43 mm above the casting surface. The second crucible 10 was moved approx. 5 mm from the first crucible in the opposite direction of the wheel's rotation. The second crucible 10. contained approx. 5.6 g of an alloy composition Fe4QNi4QB20 calculated as atomic percent. In what follows, the alloy is called Alloy II.

One edge of the nozzle opening of the second crucible

10 was placed on the same circumferential line in relation to the wheel as an edge of the nozzle opening of the first crucible, so that the 2 nozzle openings would not overlap significantly when replaced.

In this example, both crucibles 10 and 11 lay in the general plane described by the wheel. Measured in the opposite direction of the wheel's rotation, the first crucible 11 is 1.5° from the vertical and the second crucible 12 40° from the vertical. In this example, the crucibles were heated to approx. 1350°C with an induction heating coil to melt their contents. The atmosphere in the crucibles was argon at atmospheric pressure, although protective atmospheres are not de- . making in the present invention. The casting surface was moved past the nozzles at a surface speed of 32 linear meters per second. Sec. and the crucibles were simultaneously over-pressured with argon to squeeze out the contents, the first crucible 11 with 0.136 atmospheres and the second crucible 10 with 0.476 atmospheres. A continuous duplex bond was formed which lifted from the casting surface during approx. 1/2 second.

The tape was flat with a width of approx. 4.5 mm. The band lot that came from the first crucible 11 was approx. 2.7 mm wide and approx. 30 pm thick with the other part approx. 50 um thick. The rib was tough and, when broken during testing, showed no preferential splitting at the joint or transition zone. Both portions of the ribbon in this example were amorphous.

It has been found that beyond a very small distance from the joint between the two parts of the rib of an order of magnitude less than 0.5 mm, the composition of one part is not contaminated with metals from the other. Thus, when analyzing nickel on the wheel side of the belts, a strong nickel peak was observed for 1.6 mm which dropped to zero peak height over a distance of 0.05 mm at the joint. See the nickel curve shown in fig.

8 where the height of the nickel curve is directly proportional to

the amount of nickel in the Alloy II part of the band. Also a search for silicon had a sharp interruption at the junction which then dropped to zero peak height. See the silicon curve shown in fig. 9 where the height of the silicon curve is directly proportional to the amount of silicon in the Alloy I part of the band. The horizontal axis of the curve in fig. 8 and 9 indicate distance, as the curve part extends over a complete distance of approx. 4 mm.

The curve in fig.10 shows the Knoop hardness of this strip at a load of 200 g. The curve shows that the transition zone, i.e. the extent of the joint where Alloy I and II strip parts are metallurgically alloy bonded together, has a width of approx. 1.15 mm. As shown in fig. 10, the strength of Alloys I and II, respectively, remains essentially constant outside the transition zone. It should be noted that although the strength of the bond at the transition zone normally has a value between the strength of the adjacent portions of certain alloys, the metallurgical alloy bond at the transition zone may have a strength higher or lower than that of the adjacent portions, or the transition zone may consist of a separate alloy with other desired properties such as corrosion resistance, electrical resistance and the like. With the correct choice of non-uniform alloys, a combination alloy can thus be formed within the transition zone. Likewise, the right alloys can be chosen which could give crystalline band parts and an amorphous transition zone or vice versa.

In general, the transition zone which metallurgically alloy-bonds various band portions has an identifiable width of less than approx. 1.5 mm or less than approx. 5 times the average dimension of the bonded nonuniform portions. Preferably, the width of the transition zone is less than 3 times the average dimension or thickness of the bonded portions.

Although a duplex tape in particular is mentioned, it is therefore possible to produce multiplex tapes with any number of non-uniform parts through the present invention. E.g. a multiplex band can be produced which has a preferred composition for a cutting edge of a razor blade on both outer edges and an intermediate wide band of suitable background material for the cutting edge material. Such a band can then be shaped into double-edged razor blades or can be split lengthwise into single-edged razor blades.

In another example, the stainless steel cutting edge composition can be used for a central portion of the band which is then split longitudinally through the central portion to provide 2 duplex shaped bands. A possible advantage of such trip-lex tape is that it maintains its shape when coiled for storage and subsequent processing.

During continuous casting of multiplex band material, a tendency of the band 30 to stick to the casting surface 18 over a considerable portion such as several meters or more past the nozzle has been observed. This phenomenon is advantageous when casting multiplex bands through offset nozzles as shown in fig. 3, 5 and 6, but it is understood that if the strip material remains on the rotating casting drum or wheel 13 through one full revolution, damage could occur to the crucibles. It has been found that the use of a doctor blade such as a knife type element riding at or near the drum surface 18 approximately 75 cm to 1.8 m from the nozzle can counteract such sticking. With such a device, the molded band can be removed from the drum of such a doctor blade. Such a doctor blade has been found particularly useful in the production of thinner amorphous strip materials which are found to have a greater tendency to adhere to the casting surface 18 than crystalline strip materials do. It is believed that the force holding the tape back on the surface is due to the quality of the thermal contact between the tape and the casting surface. Alternative devices such as an air knife can also be used to separate the belt from the wheel.

The casting of multiplex tape materials of relatively high quality which possibly contain amorphous tape parts, which for the purposes of the present invention contain materials which are at least 50% amorphous, are realizable and practical using the apparatus and the method described above. The cooling rates must understandably normally be higher for amorphous materials compared to crystalline materials. If necessary, the cooling rates can be accelerated such as by increasing the speed of the casting surface or the like.

Typical alloys that can be cast into multiplex tapes according to the present invention are those in which at least one part consists of an alloy with iron, nickel, cobalt and combinations or mixtures thereof as a main component. Main components are those that dominate the composition so that no other element is present in a larger quantity based on atomic percentages. Such alloys often contain as minor components silicon, boron, phosphorus, carbon, aluminium, vanadium, beryl, chromium and combinations or mixtures thereof. Only random impurities less than 1%

.and preferably less than 0.1% should be present in such alloys. As mentioned above, such alloys are preferably amorphous, but crystalline alloys and combinations of crystalline and amorphous alloy parts are covered by the multiplex band according to the present invention. Preferred iron-based alloys for portions of the belt according to the present invention include the following<1>:

Although the preferred embodiment is described above for illustrative purposes, a person skilled in the art will be able to make numerous variations of details within the scope of the inventive idea.

Claims (27)

1. Rapidly cooled, cast metal strip comprising several non-uniform parts, characterized in that each part is metallurgically alloyed during casting to adjacent parts along the length of the strip. 2. Band according to claim 1, characterized in that at least 2 adjacent parts of the band have non-uniform atomic arrangements. 3. Tape according to claim 2, characterized in that at least one non-uniform part of the tape is amorphous. 4. Tape according to claim 2, characterized in that at least one non-uniform part of the tape is crystalline. 5. Tape according to claim 1, characterized in that the metallurgical alloy bond is formed in a transition zone which is amorphous and where the non-uniform parts that abut this transition zone are crystalline. 6. Strip according to claim 1, characterized in that adjacent non-uniform parts are amorphous and the metallurgical alloy bond is formed at a transition zone between these which is crystalline. 7. Band according to claim 1, characterized in that at least one non-uniform part of this band is stainless steel. 8. Tape according to claim 1, characterized in that at least 2 adjacent parts of this tape have different chemical compositions. 9. Tape according to claim 1, characterized in that at least 2 adjacent parts of the tape have non-uniform thickness. 10. Tape according to claim 1, characterized in that at least 2 adjacent parts of the tape have non-uniform corrosion resistance properties. 11. Tape according to claim 1, characterized in that at least 2 adjacent parts of the tape have non-uniform electrical properties. 12. Tape according to claim 1, characterized in that at least 2 adjacent parts of the tape have non-uniform expansion characteristics. 13. Tape according to claim 1, characterized in that at least one part comprises an alloy with main constituents selected from the group consisting of iron, nickel and cobalt and mixtures thereof, and minor constituents selected from the group consisting of silicon, boron, phosphorus, carbon, aluminium, vanadium, beryllium, chromium and mixtures thereof with negligible impurities. 14. Tape according to claim 1, characterized in that at least one part is at least 50% amorphous and has a composition of Feon _ 'Si_ _ Bn. 1C based on atomic oi) — ob 3 — 1 1U — lb percentages. 15. Tape according to claim 1, characterized in that at least one part is at least 50% amorphous and has a composition of Fe_r. _. Ni B based on atomics ^ 36-43 36-43 17-22 percentages. 16. Tape according to claim 1, characterized in that at least one lot is at least 50% amorphous and has a composition of Fe00 B Si based on atomic percentages. o U 1 Z o 17. Tape according to claim 1, characterized in that at least one part is at least 50% amorphous and has a composition of Fe7 g B^^ Si^. based on atomic percentages. 18. Tape according to claim 1, characterized in that at least one part is at least 50% amorphous and has a composition of Feg-^ B, -. Si,, based on atomic percentages. 19. Tape according to claim 1, characterized in that at least one part is at least 50% amorphous and has a composition of Feg4 B Si^ based on atomic percentages. 20. Tape according to claim 1, characterized in that the metallurgical bond is formed in a transition zone between parts with a width of less than approx. 1.5 mm. 21. Tape according to claim 1, characterized in that the metallurgical bond is formed by a transition zone between parts with a width less than 5 times the average thickness of the joined parts. 22. Tape according to claim 1, characterized in that the metallurgical bond is formed at a transition zone with a mechanical strength that is greater than the 2 adjacent bonded parts. 23. Tape according to claim 1, characterized in that the metallurgical alloy bond is formed at a transition zone with a lower mechanical strength than that of both adjacent bonded parts. 24. Procedure for casting a metallic band with several non-uniform parts that are metallurgically alloyed along the length of the band characterized by emits a first stream of molten metal from a nozzle in a first crucible to a casting surface moving at a speed of from 60 to 3000 linear surface meters per second. my. past the nozzle and emits at least one further disparate stream of molten metal from a nozzle in a crucible to this casting surface such that an outer edge portion of this at least one further stream comes into contact with an outer edge portion of the adjacent dissimilar metal providing a metallurgical alloy bond between them during casting . 25. Apparatus for casting a metallic strip with several dissimilar parts which are metallurgically alloy-bonded along the strip's longitudinal direction, characterized in that a first crucible with an internal cavity for receiving and containing metal and a nozzle through which a first stream of molten metal is emitted from the cavity to a cast-over plate located within approx. 3 mm from the nozzle and is movable past the nozzle at a speed of 60 to 3000 linear surface meters per second. my., at least one further crucible with an internal cavity for receiving and containing molten metal and a nozzle through which at least one further unequal stream of molten metal is emitted from the cavity to the casting surface located approx. 3 mm from the nozzle, as at least one further crucible has a nozzle positioned in such a way that an external edge portion of this at least one additional stream comes into contact with an ■external edge portion of adjacent different metal, which provides a metallurgical alloy bond between them during casting. 26. Apparatus according to claim 25, characterized in that the crucible is constructed of a molten metal-resistant material selected from the group silicon oxide, aluminum oxide, graphite, aluminum oxide graphite, clay graphite, burnt clay, quartz, boron nitride, silicon nitride, silicon carbide, boron carbide, zirconium oxide, stabilized zirconium oxide silicate , magnesium oxide, chrome-magnesite, kaolin fibers and combinations of these. 27. Apparatus according to claim 25, characterized in that at least part of the nozzle in this crucible is constructed of a molten metal-resistant material from the group silicon oxide, aluminum oxide, graphite, aluminum oxide graphite, clay graphite, burnt clay, quartz, boron nitride, silicon nitride , silicon carbide, boron carbide, zirconium oxide, stabilized zirconium oxide silicate, magnesium oxide, chrome-magnesite, kaolin fibers and combinations thereof.