EP0040069B1 - Strip casting apparatus - Google Patents
Strip casting apparatus Download PDFInfo
- Publication number
- EP0040069B1 EP0040069B1 EP81302059A EP81302059A EP0040069B1 EP 0040069 B1 EP0040069 B1 EP 0040069B1 EP 81302059 A EP81302059 A EP 81302059A EP 81302059 A EP81302059 A EP 81302059A EP 0040069 B1 EP0040069 B1 EP 0040069B1
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- EP
- European Patent Office
- Prior art keywords
- casting
- orifice passage
- side portion
- strip
- inch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
- B22D15/04—Machines or apparatus for chill casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/005—Continuous casting of metals, i.e. casting in indefinite lengths of wire
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/064—Accessories therefor for supplying molten metal
- B22D11/0642—Nozzles
Definitions
- the outer lip projecting surface 38 of the first side portion 32 and the bottom surface 48 of the second side portion 34 are ground by the grit side of the sandpaper into substantially complete parallelism with the casting surface 14.
- Such parallelism may be achieved on most refractory nozzles, even when round or other curvilinear casting surfaces are employed. To achieve such parallelism by this procedure 400 or 600 grit sandpaper has been found to be adequate.
- the width b of the orifice passage 30 is typically in the range of from about 0.254 to about 1.016 mm (about 0.010 to about 0.040 inch). In the production of crystalline strip material, such as stainless steel, the width b of the orifice passage 30 may be greater, perhaps as high as about 2.032 mm (0.080 inch) if thick strip is being uniformly produced.
- Dimension e representing the cross-sectional thickness of the curvilinear element 24, f, representing the width to which a top portion of the orifice passage 30 may be relieved, and g, representing the depth to which a top portion of the orifice passage 30 may be relieved, appear to be somewhat arbitrary.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
Description
- The present invention relates to strip casting apparatus for the casting of strip material at high quench rates and at high production rates. More particularly, the present invention is directed to apparatus for rapidly casting thin metallic strip material.
- Incorporated herein, by reference, is the subject matter of co-filed European Patent Applications entitled "Method and Apparatus For Strip Casting" (Publication Number 0040070), "Method of Repetitiously Marking Continuously Cast Metallic Strip Material" (No. 0040071), "Apparatus For Strip Casting" (No. 0040072) and "Strip Casting Apparatus" (No. 0040073).
- The apparent advantages and economic significance of producing thin metallic strip . material by casting process, as compared to the conventional rolling or reducing operations, are numerous. The fact that strip casting may be performed at such high quench rates as to produce amorphous material is even more meaningful. However, it is equally apparent that there are a multitude of strip casting parameters which must be controlled or monitored to assure that the cast strip is of acceptable quality and of uniform composition and structure. For these reasons, those skilled in the art appreciate the intricacies involved in the development of a commerically successful strip casting apparatus.
- The general concept of casting thin metallic materials such as sheet, foil, strip and ribbon was disclosed in the early 1900's. For example, United States Patents Nos. 905,758 and 993,904 teach processes wherein molten material flows onto a moving cool surface and the material is drawn and hardened thereon into a continuous thin strip. These references teach that molten metal may be poured onto the smooth peripheral surface of a rotating liquid- cooled copper drum or disc to form strip materials. Despite early disclosure of such concept, there is no evidence of commercial success of strip casting during the early part of the 20th century.
- Recently, in United States Patent Nos. 3,522,836 and 3,605,863 a method for manufacturing a continuous product, such as metallic wire or strip, from molten metal has been disclosed. These references teach that a convex meniscus of molten material should project from a nozzle. A heat extracting surface, such as a water-cooled drum, is moved in a path substantially parallel to the outlet orifice and into contact with the meniscus of molten metal to continuously draw material from the meniscus to form a uniform continuous product. The above-described method is commonly called the "melt drag" process as the heat extracting surface moving past the meniscus of molten metal at the nozzle orifice actually has an effect on the rate of molten metal flow, or drag through the nozzle.
- More recent strip casting developments focus on relatively narrow refinements in the metallic strip casting art. For example, United States Patent No. 4,142,571 is particularly directed to a slot construction in a metal strip casting nozzle having stringent dimensional requirements. Also, United States Patent No. 4,007,462 pertains to the provision of a specific construction for a stationary housing above the peripheral surface of a chill roll used for strip casting.
- There are a number of other rapid quenching techniques known in the art. For example, melt spinning processes of producing metallic filament by cooling a fine molten stream either in free flight or against a chill block have been practised. Also known are melt extraction techniques, such as crucible melt extraction disclosed in United States Patent No. 3,838,185, pendant drop melt extraction techniques taught in United States Patent No. 3,896,203 and splat cooling explained in United States Patent No. 3,297,436. It has been found difficult to produce uniform sheet or strip by such alternative techniques of rapid quenching. There are many factors, such as casting temperature and pressure, auxiliary surface cooling rates, surface coatings for the casting surface, and the like which appear to affect the product thickness, the quality and the reproducibility of rapidly cast strip material.
- Despite the relatively long history of the art of strip casting, and the recent developments in this area, strip casting is not a widely accepted and commercially significant operation at the present time. It appears that various improvements, modifications and/or innovations are required in the art before there is likely to be any significant commercial impact in the art of strip casting. In particular, proper relationships among such variables as molten metal tundish construction, nozzle orifice size and dimensions, spacing from a casting surface, speed at which such surface is moved, quench rates, metal temperature and feed rates, and the like may require more accurate identification and interrelation in order to accomplish the uniformity and consistency required for successful, commercial production of cast strip. In particular, certain nozzle structures and their dimensional relationship to the casting surface onto which strip material is cast, have been found to be desirable to yield uniform strip casting results when utilized in various casting parameters.
- Accordingly, a new and improved apparatus for casting relatively wide, thin strip material is desired which overcomes the disadvantages of the prior art structures. Such desired apparatus should be reliable, more efficient and more effective than the structures disclosed in the prior art, and should lead to reproducibility, uniformity and consistency in strip casting.
- The present invention has as an object thereof the provision of a strip casting apparatus which is capable of continuously casting metallic strip material of substantially uniform dimension and substantially uniform quality throughout its length.
- Another object of the present invention is to enable the provision of a strip casting apparatus having a nozzle construction which promotes the efficient rapid casting of metal strip material with a minimum of metal turbulence during casting.
- Another object of the present invention is to provide a strip casting apparatus capable of reproducing successful strip casting operations.
- Another object of this invention is to provide a strip casting apparatus which can effect sufficiently rapid quenching of the produced strip to result in the production of amorphous strip. However, it should be understood that the production of continuously cast crystalline material is equally comprehended by the present invention.
- A further object of this invention according to a preferred embodiment thereof, is to identify certain design and dimensional requirements, particularly with regard to nozzle structure, which permit continuous and repetitious rapid casting of metallic strip material of uniform dimension and uniform quality.
- United States Patent No. 4,142,571 has been mentioned above. The disclosure of that document includes apparatus for continuously casting metal strip comprising a tundish for receiving and holding molten metal, a nozzle comprising a curvilinear element disposed in the tundish, said curvilinear element having an orifice passage therein, with the longitudinal extent of the orifice passage approximating the width of the strip to be cast, said orifice passage having substantially uniform cross-sectional dimensions throughout the longitudinal extent thereof, and a cooled casting surface at least as wide as the strip to be cast, disposed at a standoff distance of less than 3.048 mm (.120 inch) from the nozzle, movable past the orifice passage in a direction substantially perpendicular to the longitudinal axis of the orifice passage, said orifice passage defined between a first side portion and a second side portion of the curvilinear element. In accordance with the present invention, such apparatus is characterised in that said first side portion has a substantially planar inside surface with respect to the orifice passage, and an outer, lip projecting surface at the discharge end of the orifice passage disposed toward, and facing the casting surface for a distance before the outer, lip projecting surface of the first side portion is relieved to define a lip projection.
- The invention will be more particularly described with reference to the accompanying drawings, in which:-
- Figure 1 is a diagrammatic side elevation, partially in cross-section, illustrating apparatus according to the present invention for continuously casting strip material.
- Figure 2 is a fragmentary cross-sectional view on a larger scale of part of a tundish and nozzle forming part of the apparatus of Figure 1.
- Figure 3 is a perspective view on a still larger scale of a curvilinear element which forms the nozzle shown in Fig. 2.
- Figure 4 is an even more enlarged fragmentary cross-sectional view through the orifice passage of the nozzle element shown in Figures 2 and 3.
- Figure 5 is a fragmentary cross-sectional view on the same scale as Fig. 4 through the orifice passage of an alternative form of nozzle element which can be used in the apparatus of the present invention.
- Figure 6 is a cross-sectional view on substantially the same scale as Fig. 2 of the orifice passage of another alternative nozzle element which can be used in the apparatus of the present invention.
- Figure 7 is a view similar to Figs. 4 and 5 but illustrating a further alternative orifice passage in a nozzle element which can be used in apparatus according to the present invention, and
- Figure 8 is a view similar to Fig. 7 but illustrating yet another alternative orifice passage in a nozzle element for use in apparatus according to the present invention.
- Referring to the drawings, Figure 1 generally illustrates apparatus according to the present invention for casting
metallic strip material 10. This apparatus includes a casting drum, wheel, belt, or the like upon which thestrip 10 is cast. In the preferred embodiment illustrated acontinuous strip 10 is cast onto a smooth, outerperipheral surface 14 of a circular drum orwheel 12 as shown in Figure 1. It should be understood that configurations other than circular may be employed. For example, a wheel with a smooth, frustoconical outer peripheral surface (not shown) may be employed. Also, a belt capable of rotating through a generally ovular path may be employed as the casting element. Regardless of the configuration employed, thecasting surface 14 should be cooled to a temperature below the solidus temperature of the metal being cast and should be at least as wide as the strip to be cast. - In the preferred embodiment, the
casting surface 14 comprises the surface of the water cooled, precipitation hardenedcopper alloy wheel 12 containing about 98% copper with about 2% chromium. Copper and copper alloys are preferable because of their high thermal conductivity and wear resistance. However, berillium copper alloys, steel, brass, aluminum, aluminum alloys or other materials may be utilized alone, or in combination. For example, multipiece wheels having outer peripheral sleeves of molybdenum or other material may be employed. Likewise, cooling may be accomplished with the use of a medium other than water. Water is typically chosen for its low cost and its ready availability. - In the operation of the strip casting apparatus of the present invention, the
surface 14 of thecasting wheel 12 must be able to absorb the heat generated by contact with molten metal at theinitial casting point 16, and such heat must be conducted substantially into the copper wheel during each rotation of the wheel. Theinitial casting point 16 refers to the approximate location on thecasting surface 14 wheremolten metal 20 flowing from a crucible or tundish 22 contacts thecasting surface 14. Cooling, by heat conduction, may be accomplished by delivering a sufficient quantity of water through internal passageways located near the periphery of thecasting wheel 12. Alternatively, the cooling medium may be delivered directly to the underside of the casting surface. Understandably, refrigeration techniques and the like may be employed to accelerate or decelerate cooling rates, and/or to effect wheel expansion or contraction during strip casting. - Whether a drum, wheel or belt is employed for casting, the casting surface should be generally smooth and symmetrical to maximize uniformity in strip casting. For example, in certain strip casting operations the distance between the outer
peripheral casting surface 14 and the surfaces defining the orifice passage of the nozzle which feeds the molten material onto the castingsurface 14 must not deviate from a desired or set distance during the casting operation. This distance shall hereinafter be called the stand-off distance or gap. It is understandable that the gap should be substantially maintained throughout the casting operation when it is the intention to cast uniform strip material. - It should be understood that if the casting is performed on a rotating body, such as a drum or the
wheel 12, the rotating body should be carefully constructed so as not to be out-of-round during operation to ensure uniformity in strip casting. Along these lines, it has been found that a drum or wheel which is out-of-round by about 0.508 mm (6.020 inch), or more, may have a magnitude 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, as well as the elimination of problems associated with weld porosity, may be more readily accomplished by fabricating a wheel or drum from a single integral slab of rolled or forged copper alloy. However as mentioned above, alternative materials including sleeves and coatings may be employed. - The
molten material 20 to be cast in the apparatus described herein is preferably retained in the crucible ortundish 22, which is provided with a discharge nozzle. The nozzle is typically, though not necessarily, located at a lower portion of thetundish 22, as shown in Fig. 1, and thenozzle 24 comprises acurvilinear element 24 mounted in thetundish 22. - The
curvilinear element 24, located in or forming a lower portion of thetundish 22 is best shown in thetundish 22 in Figure 2, and in perspective view in Figure 3. As shown in the drawings, anorifice passage 30 is preferably substantially centrally located in thenozzle element 24. Such approximate central location of the orifice passage, orslot 30 helps to assure uniformity as the pressure of the molten metal bearing thereagainst is substantially equalized during the casting operation. It should be understood, however, that the slot may be located in off-center positions as may be desired. - The longitudinal extent of the
orifice passage 30 should approximate the width of the strip to be cast. There does not appear to be a limitation on the longitudinal extent of the orifice passage, and, passages as long as 915 mm (thirty six inches), or longer, in a curvilinear element may be used. It is highly desired that the molten metal flow uniformly through theorifice passage 30 in thecurvilinear nozzle element 24 in order to form uniform, high quality strip material. In an alternative embodiment, strip of various widths may be produced by cutting multiple longitudinally alignedorifice passages 30 of appropriate longitudinal extent in thecurvilinear element 24 forming the nozzle of atundish 22, as opposed to asingle orifice passage 30. Regardless of the size of theorifice passage 30, or passages, the cross-sectional dimensions of eachpassage 30 should be substantially uniform throughout the longitudinal extent thereof to produce strip material having uniform dimensions. In the operation of the strip casting apparatus of the present invention, the cooled castingsurface 14 moves past theorifice passage 30 in a direction substantially perpendicular to the longitudinal axis of thepassage 30. - As best shown in Figure 4, the
orifice passage 30 is defined between afirst side portion 32 and asecond side portion 34 of thecurvilinear element 24. Thefirst side portion 32, is located on the downstream side of theorifice passage 30, with respect to the direction of movement of the castingsurface 14 indicated by the arrow in Figure 4. Thefirst side portion 32 has aninside surface 36 which is substantially planar, and an outerlip projecting surface 38 disposed toward and facing the castingsurface 14. At a downstream location from theorifice passage 30, the outerlip projecting surface 38 is relieved, such as at 40, to define alip projection 42. Thesecond side portion 34 is located on the upstream side of theorifice passage 30, with respect to the direction of movement of the castingsurface 14 indicated by the arrow in Figure 4. Thesecond side portion 34 has aninside surface 46, which preferably, is substantially planar and, also preferably, is substantially parallel to and facing theinside surface 36 of thefirst side portion 32 at least at an outer portion of theorifice passage 30 with respect to the direction of metal flow from thetundish 22 through thepassage 30. Abottom surface 48 of thesecond side portion 34 is disposed toward and facing the castingsurface 14. - In a preferred embodiment, the outer
lip projecting surface 38 of thefirst side portion 32 and a portion of thebottom surface 48 of thesecond side portion 34 are in substantially complete parallelism with the castingsurface 14 movable therebelow. When utilizing a drum orwheel 12, and a grindablecurvilinear element 24, such substantially complete parallelism may be accomplished by placing a sheet of sandpaper, or the like, against the castingsurface 14 with the grit side of the sandpaper facing the curvilinear element. By moving the curvilinear element into tight contact with the castingsurface 14, with the sandpaper disposed therebetween, and by moving the castingsurface 14 and sandpaper simultaneously past thenozzle 24, the outerlip projecting surface 38 of thefirst side portion 32 and thebottom surface 48 of thesecond side portion 34 are ground by the grit side of the sandpaper into substantially complete parallelism with the castingsurface 14. Such parallelism may be achieved on most refractory nozzles, even when round or other curvilinear casting surfaces are employed. To achieve such parallelism by this procedure 400 or 600 grit sandpaper has been found to be adequate. - By maintaining at least a portion of the outer
lip projecting surface 38 in complete parallelism with the castingsurface 14, the standoff distance, or gap h between the outerlip projecting surface 38 and the castingsurface 14 may be maintained throughout the length of theprojection 42. It has been found that the gap h between the outerlip projecting surface 38 and the castingsurface 14 must be maintained at less than about 3.048 mm (0.120 inch) in order to successfully cast strip material. Preferably, this gap h is maintained at less than about 2.032 mm (0.080 inch) and for casting certain alloys into thin gauge strip, a gap h of less than 0.254 mm (0.010 inch) is preferred. It has also been found that the gap h between thebottom surface 48 of thesecond side portion 34 does not appear to be as critical. What is preferred with respect to thesecond side portion 34 is that theinside surface 46 thereof extend toward the castingsurface 14 while parallel to theinside surface 36 of thefirst side portion 32, at least in an outer portion of theorifice passage 30, so as not to interfere with the maintenance of a stable flow of molten metal through thepassage 30 in thecurvilinear element 24 and onto the movingcasting surface 14. Accordingly, thebottom surface 48 of thesecond side portion 34 may just clear the castingsurface 14, i.e. be within about 0.0508 mm (.002 inch) thereof as shown in Figure 7, or alternatively, thebottom surface 48 may be tapered from the orifice in a direction away from the castingsurface 14, as shown in Figure 8. In any event, the gap h between thebottom surface 48 of thesecond side portion 34 and the castingsurface 14 must be sufficiently restricted at the nozzle to prevent significant molten metal backflow therebetween during casting. - In an alternative embodiment, shown in Figure 5, the
inside surface 36 of thefirst side portion 32 extends through acurvilinear surface 50 to the outerlip projecting surface 38, rather than through the abrupt 90° juncture shown in Figure 4. Providing such radiusedcorner surface 50 has been found beneficial in the production of certain grades of strip material. More particularly, suchradiused corner surface 50 helps minimize molten metal turbulence during strip casting and, therefore, results in more uniform production parameters. It has also been found that a sharp corner between theinside surface 36 and the outerlip projecting surface 38 may be subjected to various pressures and flow patterns which could create stress conditions forcurvilinear elements 24 made of certain materials and, in some instances, may break, crack or wear during casting thereby upsetting balanced strip casting conditions. Providing such roundedcorner surface 50 may minimize the adverse affects of such turbulence and metal flow through thecurvilinear element 24 comprising the nozzle of thetundish 22. - To further minimize turbulence during strip casting through the apparatus of the present invention, an inside portion of the
orifice passage 30 may be relieved, or tapered. As shown in the drawings, both thefirst side portion 32 and thesecond side portion 34 may be cut into a v-shape, or a more rounded U-shape at an inside portion thereof, creating an initial funnel type structure, which further maximizes uniformity in metal flow patterns and minimizes irregularities or turbulence during strip casting. - The
crucible 22 is preferably constructed of a material having superior insulating ability. If the insulating ability is not sufficient to retain the molten material at a relatively constant temperature, auxiliary heaters such as induction coils may have to be provided in and/or around thecrucible 22, or resistance elements such as wires may be provided. A convenient material for the crucible is an insulating board made from fiberized kaolin, a naturally occurring, high purity, alumina-silica fire clay. Such insulating material is available under the trade name Kaowool HS board. However, for sustained operations, and for higher melting temperature alloys, various other materials may have to be employed for constructing thecrucible 22 or thecurvilinear element 24 including graphite, alumina graphite, quartz, clay graphite, boron nitride, silicon nitride, silicon carbide, boron carbide, alumina, zirconia and various combinations or mixtures of such materials. It should also be understood that these materials may be strengthened; for example fiberized kaolin may be strengthened by impregnating with a silica gel or the like. - It is imperative that the
orifice passage 30 of thecurvilinear element 24 remain open and its configuration remain substantially stable throughout a strip casting operation. It is understandable that theorifice passage 30 should not erode or clog, significantly, during a strip casting operation or the primary objectives of maintaining uniformity in the casting operation and of minimizing metal flow turbulence in thetundish 22 may be defeated. Along these lines, it appears that certain insulating materials may not be able to maintain their dimensional stability over long casting periods. To obviate this problem,side portions orifice passage 30 of thecurvilinear element 24 may be constructed of a material which is better able to maintain dimensional stability and integrity during exposure to high molten metal temperatures for prolonged time periods. Such materials may take the form of a single, generallysemi-circular element 24 with aslot 30 cut therethrough as shown in Figure 3. Alternatively, thecurvilinear element 24 may comprise a pair of facing inserts held in thecrucible 22 to form aslot 30 therebetween as shown in Figure 6. In a preferred embodiment theorifice passages 30 in singlecurvilinear element 24 may be cut ultrasonically to ensure that the desired slot dimensions are accurately provided. Suchcurvilinear elements 24 may be constructed of materials such as quartz, graphite, clay graphite, boron nitride, alumina graphite, silicon carbide, stabilized zirconia silicate, zirconia magnesia, alumina, or other similar molten metal resistant materials. Thesecurvilinear elements 24 may be held in thecrucible 22 mechanically, and/or with the aid of adhesives such as various refractory cements. - The drive system and housing for the drum wheel or
other casting surface 14 of the present invention should be rigidly constructed to permit drum rotation without structural instability which could cause the drum to slip or vibrate. In particular, care should be taken to avoid resonant frequencies at the operating speeds for the castingsurface 14. The castingsurface 14 should be capable of moving at a surface speed of from about 61 linear surface metres (200 linear surface feet) per minute to more than about 3048 linear surface metres (10,000 linear surface feet) per minute. When utilizing;a drum having a circumference of about 2.44 metres (8 feet), this rate calculates to a drum speed from about 25 rpm to about 1250 rpm. A three horsepower variable speed reversible, dynamically braked motor provides an adequate drive system for an integral copper alloy casting drum about 50.8 mm (2 inches) thick and about 2.44 metres (8 feet) in circumference. - In one embodiment, the casting
surface 14 on the wheel or drum of the apparatus of the present invention is smooth. It has been found that in certain applications, such as for producing amorphous materials, finishing theperipheral surface 14 of a castingdrum 12 with 400-grit sandpaper and preferably with 600 grit sandpaper may yield improved product uniformity. - In a preferred embodiment as illustrated in Figure 2, the
crucible 22 is constructed of an insulating board, such as Kaowool HS Board, and thecurvilinear element 24, as shown in Figure 3, is made of clay graphite, a molten metal resistant material, held in the walls of thecrucible 22. Theorifice passage 30 is cut ultrasonically in theclay graphite element 24. Thefirst side portion 32 and thesecond side portion 34 of thecurvilinear element 24 define the orifice passage, or slot, 30 therebetween. As an alternative, preferred examples of thecurvilinear element 24 materials, a plate made of quartz or vycor material, which are highly molten metal resistent materials, having a width such as about 38 mm (one and one half inch) may be bent around an appropriate small radius, as shown in the drawing. Alternatively, thecurvilinear element 24 may comprise cast boron nitride. The desired slot forming theorifice passage 30 in thecurvilinear element 24, may be accurately cut therein with an ultrasonic drill. A preferred one piece,curvilinear element 24, as best illustrated in Figures 2, 3 and 4 may be constructed of a semi-circular ring of molten metal resistent material. In this example, a slot b having a width of about 0.254 mm to about 2.032 mm (0.010 to about 0.080 inch) between parallel inside surfaces 36 and 46 may be ultrasonically drilled into a clay graphite insert material, and the insert may be mounted into thecrucible 22 as shown in Figure 2. It should be understood that the design of the outer, peripheral edges of such curvilinear element nozzle may be modified to assist in holding thecurvilinear element 24 in the walls of thecrucible 22. -
- In the production of amorphous strip materials, the width b of the
orifice passage 30 is typically in the range of from about 0.254 to about 1.016 mm (about 0.010 to about 0.040 inch). In the production of crystalline strip material, such as stainless steel, the width b of theorifice passage 30 may be greater, perhaps as high as about 2.032 mm (0.080 inch) if thick strip is being uniformly produced. - Dimension e representing the cross-sectional thickness of the
curvilinear element 24, f, representing the width to which a top portion of theorifice passage 30 may be relieved, and g, representing the depth to which a top portion of theorifice passage 30 may be relieved, appear to be somewhat arbitrary. Primarily, the purpose of the relief at a top portion of theorifice passage 30, identified by dimensions f and g in Figure 4, is to eliminate clogging of molten metal in the orifice. - Molten metal turbulence during strip casting may be minimized, and perhaps avoided by relieving sharp corners of the nozzle in the direction of casting. It will be understood that such corner relief, such as radiused
corner surface 50 shown in Figure 5, may be accomplished by constructing thecurvilinear element 24 of an eroding material, such as Kaowool HS board, which may provide natural erosion as a result of the strip casting operation. Turbulence may also be avoided by completely rounding thecorner 50 of theprojection 42 on thefirst side portion 32 of thecurvilinear element 24 as is shown in Figure 5 during or after manufacture thereof. - In an exemplary operation of the apparatus of the present invention, molten metal is delivered to a
heated crucible 22. It is understood that a heater, such as induction coils of resistance wire, may be provided in and above thecrucible 22 to maintain relatively constant molten metal temperatures as may be desired. Alternatively, the molten metal may be poured directly into a preheated crucible. The preheat temperature should prevent freezing or clogging of theorifice passage 30 during the initial casting operation, and the temperature of the flowing metal should thereafter keep thecrucible 22 andcurvilinear element 24 forming the nozzle at sufficient temperature to ensure uninterrupted molten metal flow through theorifice passage 30. In certain applications, thecurvilinear element 24 may be externally heated throughout the casting operation. Also, the metal which is fed to thecrucible 22 may be superheated to allow a certain degree of temperature loss without adversely affecting metal flow through theorifice passage 30. - Also, a metallostatic head height in the
tundish 22 should be maintained at a relatively constant level, typically less than 254 mm (ten inches) above theorifice passage 30, throughout the casting operation to assure that a relatively constant static head pressure may be maintained at theorifice passage 30. This may be accomplished by initially pouring themolten metal 20 into thecrucible 22 to the desired height and thereafter controlling the rate at which additionalmolten metal 20 is poured into thecrucible 22 to maintain the desired metallostatic head. It is understandable that the rate at which additionalmolten metal 20 is fed to thecrucible 22 should be in substantial conformity with the rate at which metal flows from theorifice passage 30 onto the castingsurface 14 in formingstrip material 10. Maintenance of a relatively constant height of metal in thecrucible 22 assures that the molten metal flow pressure through theorifice passage 30 is maintained relatively constant so as not to adversely affect the casting operation or the quality of thestrip material 10. Alternatively, externally applied pressure may be employed to control the pressure at theorifice passage 30. - Using a tundish or
crucible 22 similar to that shown in Figure 1, made of a commercially available tundish material available under the trade name Garnex, a casting run was made on Type 304 stainless steel. Theorifice passage 30 at the base of the crucible was about 33.02 mm (1.3 inches) long and 2.032 mm (0.08 inch) wide, and the distance, or gap, between the outer,lip projecting surface 38 and castingsurface 14 was between 0.508 to 1.016 mm (0.02 to 0.04 inch). With the surface speed of a rotating water cooled copper alloy drum held at about 283 metres (930 feet) per minute, molten metal was poured into thecrucible 22 at a temperature of about 1593°C (2900°F) estimated with the use of an optical pyrometer. A metallostatic head height of approximately 152.4 mm (six inches) was maintained throughout the casting operation. The strip produced thereby was about 0.1 524 to 2.032 mm (0.006 to 0.008 inch) thick and exhibited fairly good quality in that it was tough and ductile as cast. - During casting of strip material, the tendency of the
strip 10 to adhere to thecasting surface 14 for a significant distance, such as several feet or more, beyond theinitial casting point 16 has been observed. It is understandable that if thestrip material 10 remains on a rotating casting drum orwheel 12 for a full revolution, damage to thecrucible 22, particularly to theorifice passage 30 in thecurvilinear element 24, could result. It has been found that the use of a doctor blade, such as a knife type element riding at or near thedrum surface 14, approximately 0.762 to 1.828 metres (2.5 to 6 feet) from the orifice easily counters such adherence. With such an arrangement, the cast strip may be removed from thedrum 12 by such doctor blade. Such doctor blade has been found particularly useful in the production of thinner amorphous strip materials which appear to have a greater tendency to adhere to thecasting surface 14 than do the crystalline strip materials. It is believed that the force which retains the strip on the casting surface may reflect the quality of the thermal contact between thestrip 10 and the castingsurface 14. Alternative arrangements, such as an air knife, may also be employed to separate thestrip 10 from thewheel 12. - The casting of a relatively high quality strip material including amorphous material, which for the purpose of this invention includes materials which are at least 25% amorphous, is feasible and practical using the apparatus and procedures described above. Understandably, the quench rates must be higher for amorphous material as compared to similar gauge crystalline strip material. Quench rates may be accelerated such as by increasing the speed of the casting
surface 14, or the like. It is important to recognize that the process may be conducted in two effective modes. With theorifice passage 30 quite close to thecasting surface 14 as measured between the outerlip projecting surface 38 and the castingsurface 14, strip perhaps 0.025 to 0.0762 mm (0.001 to 0.003 inch) thick can be cast of either amorphous or crystalline materials, If the outerlip projecting surface 38 of thefirst side portion 32 of thecurvilinear element 24 is disposed further away from the castingsurface 14, and as casting surface speeds are reduced, strip perhaps 0.127 to 1.27 mm (0.005 to 0.050 inch) thick can be cast. In this latter mode, the quench rate may be significantly lower due at least in part to the increase in the product thickness.
Claims (23)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US14842180A | 1980-05-09 | 1980-05-09 | |
US148421 | 1980-05-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0040069A1 EP0040069A1 (en) | 1981-11-18 |
EP0040069B1 true EP0040069B1 (en) | 1984-08-01 |
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ID=22525693
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP81302059A Expired EP0040069B1 (en) | 1980-05-09 | 1981-05-08 | Strip casting apparatus |
Country Status (17)
Country | Link |
---|---|
EP (1) | EP0040069B1 (en) |
JP (1) | JPS574361A (en) |
KR (1) | KR830005942A (en) |
AT (1) | AT389252B (en) |
AU (1) | AU542805B2 (en) |
BG (1) | BG45213A3 (en) |
BR (1) | BR8102821A (en) |
CA (1) | CA1180873A (en) |
DE (1) | DE3165199D1 (en) |
ES (1) | ES502048A0 (en) |
HU (1) | HU180410B (en) |
MX (1) | MX155278A (en) |
NO (1) | NO158049C (en) |
PL (1) | PL133112B1 (en) |
RO (1) | RO84488B (en) |
SU (1) | SU1386020A3 (en) |
YU (1) | YU43228B (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0111728A3 (en) * | 1982-11-12 | 1985-04-03 | Concast Standard Ag | Method of and device for producing products in the shape of strips or foils |
GB2134428B (en) * | 1983-02-03 | 1987-06-17 | Metal Box Plc | Continuous extrusion of metals |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4142571A (en) * | 1976-10-22 | 1979-03-06 | Allied Chemical Corporation | Continuous casting method for metallic strips |
DE2856795C2 (en) * | 1977-12-30 | 1984-12-06 | Noboru Prof. Sendai Tsuya | Use of molten steel for a method of continuously casting a thin strip |
DE2952620C2 (en) * | 1979-01-02 | 1984-07-05 | Allied Corp., Morris Township, N.J. | Device for the continuous casting of vitreous metal alloy threads |
-
1981
- 1981-04-14 YU YU960/81A patent/YU43228B/en unknown
- 1981-04-29 AU AU69978/81A patent/AU542805B2/en not_active Ceased
- 1981-05-02 RO RO104227A patent/RO84488B/en unknown
- 1981-05-04 KR KR1019810001541A patent/KR830005942A/en unknown
- 1981-05-05 HU HU81811165A patent/HU180410B/en unknown
- 1981-05-07 BG BG8151978A patent/BG45213A3/xx unknown
- 1981-05-07 BR BR8102821A patent/BR8102821A/en not_active IP Right Cessation
- 1981-05-08 AT AT0205281A patent/AT389252B/en not_active IP Right Cessation
- 1981-05-08 SU SU813279043A patent/SU1386020A3/en active
- 1981-05-08 DE DE8181302059T patent/DE3165199D1/en not_active Expired
- 1981-05-08 ES ES502048A patent/ES502048A0/en active Granted
- 1981-05-08 PL PL1981231050A patent/PL133112B1/en unknown
- 1981-05-08 EP EP81302059A patent/EP0040069B1/en not_active Expired
- 1981-05-08 NO NO811574A patent/NO158049C/en unknown
- 1981-05-08 JP JP6844781A patent/JPS574361A/en active Granted
- 1981-05-08 MX MX187197A patent/MX155278A/en unknown
- 1981-05-08 CA CA000377164A patent/CA1180873A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
NO158049B (en) | 1988-03-28 |
AU542805B2 (en) | 1985-03-14 |
EP0040069A1 (en) | 1981-11-18 |
JPH0428464B2 (en) | 1992-05-14 |
PL231050A1 (en) | 1982-02-01 |
ES8303951A1 (en) | 1983-03-01 |
MX155278A (en) | 1988-02-12 |
KR830005942A (en) | 1983-09-14 |
SU1386020A3 (en) | 1988-03-30 |
RO84488B (en) | 1984-08-30 |
JPS574361A (en) | 1982-01-09 |
HU180410B (en) | 1983-03-28 |
ES502048A0 (en) | 1983-03-01 |
RO84488A (en) | 1984-06-21 |
DE3165199D1 (en) | 1984-09-06 |
NO811574L (en) | 1981-11-10 |
BG45213A3 (en) | 1989-04-14 |
CA1180873A (en) | 1985-01-15 |
YU96081A (en) | 1987-12-31 |
ATA205281A (en) | 1989-04-15 |
AU6997881A (en) | 1981-11-12 |
PL133112B1 (en) | 1985-05-31 |
AT389252B (en) | 1989-11-10 |
NO158049C (en) | 1988-07-06 |
BR8102821A (en) | 1982-02-02 |
YU43228B (en) | 1989-06-30 |
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