JPH0428464B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an apparatus for casting strip material with rapid cooling and high production rates. More particularly, the present invention relates to an apparatus for rapidly casting thin strips of metal.
There is a related application dated the same date. Producing thin metal strip material by casting techniques has significant advantages over conventional rolling drawing operations. It is of great significance to significantly increase the cooling rate during strip casting to produce an amorphous material. However, there are a large number of strip casting parameters that must be controlled and monitored in order to achieve usable quality and uniform composition of the cast strip. For this reason, in the opinion of those skilled in the art, the development of a commercially acceptable strip casting apparatus is complicated. The concept of casting thin metal materials, such as plates, membranes, strips, and ribbons, dates back to the early 1900s; for example, the methods described in U.S. Pat. , the material is tensile cured into a continuous thin strip. The method discloses flowing molten metal onto a smooth outer peripheral surface of a rotating liquid-cooled copper drum or disk.
However, in the first half of the 20th century, strip casting was not a market success. Recently, US Pat. In this method, molten metal flows out of a concave dish through a nozzle. A heat absorbing surface, such as a water-cooled drum, moves in a path generally parallel to the exit orifice and contacts the pan of molten metal to continuously draw metal from the pan to form a uniform continuous article. The method described above is referred to as melt drawing method. The heat absorbing surface of the molten metal pan passing under the nozzle orifice has the effect of molten metal flow formation or withdrawal from the nozzle. Furthermore, recent research into strip casting techniques has aimed at relatively narrow improvements in metal strip casting techniques. For example, U.S. Pat. No. 4,142,571 shows a slotted structure that defines the size range of a metal strip casting nozzle. U.S. Pat. No. 4,077,462 shows a special construction of a fixed housing on the outer circumferential surface of a cooling roll for strip casting. Other known rapid cooling techniques are implemented in which a thin melt stream is allowed to move freely or impinge on a cooling block, for example to produce metal filaments by melt swirling. Furthermore, there is US Pat. No. 3,838,185 as a melt drawing method, and US Pat. No. 3,896,203 as a rappelling melt drawing method. It is difficult to produce uniform plates or strips using this type of rapid casting technique. Many other functions, such as auxiliary surface cooling, surface coating, etc., affect product thickness and quality of rapidly cast strip materials. Although the technique of strip casting has a relatively long history and there have been recent advances, strip casting has not yet gained wide acceptance or become a major industrial practice. It appears that various improvements and inventions will be needed to make the strip casting technique a major industry operation. In particular, these improvements require precise limitations on the structure of the molten metal tundish, the size and dimensions of the nozzle orifice, the spacing from the casting surface, the speed of movement of the casting surface, the rate of quenching, the metal temperature and feed rate, etc. This provides the uniformity and continuity necessary for effective marketable production of cast strips. In particular, the structure of the nozzle and slot, and the dimensional relationship between the casting surface on which the strip is cast and the slot, have hitherto been inadequate to obtain a uniform strip casting surface. Therefore, there is a need for a new apparatus for casting relatively wide thin strips of material and overcoming the deficiencies of known constructions. The device is reliable, more efficient than known devices, and provides repeatability, uniformity, and durability for strip casting. SUMMARY OF THE INVENTION The present invention provides an apparatus for continuously casting metal strip. This device includes a tundish and a nozzle comprising a curved element, in which an orifice passageway having a uniform cross-sectional dimension over its entire longitudinal length is formed. A cool cast surface on the outside of the nozzle passes through the orifice passage in a direction generally perpendicular to the longitudinal axis. first curve element
The second inner surface defines an orifice passageway through which molten metal is supplied to the casting surface. Having a separate curved element facilitates forming the nozzle opening in the tundish. The curved element allows easy control of the direction of the nozzle opening, and as a result, the tundish feeds molten metal to the side of the casting surface, rather than only from above as in the past. be able to. The ability to supply molten metal to the sides of the casting wheel allows for better control of the separation or standoff distance between the nozzle, which bears the weight of the tundish, and the casting surface. The weight of the tundish and the changing weight of the tundish as molten metal is fed to the casting surface conventionally affect the standoff distance, but in the present case the distance between the nozzle and the casting surface is reduced compared to the conventional one. less impact on the standoff distance between the two, leading to better control. Such control leads to better casting of the product. Also, by using separate curved elements,
The precise dimensional relationship between the tundish, nozzle, orifice and casting wheel can be easily maintained. In particular, the use of separate curved elements allows the orifice passage to have a uniform cross-section over its entire longitudinal length. Conventional nozzle structures and the dimensional relationship of the nozzle structure to the casting surface have not been sufficient to provide uniform strip casting results. Therefore, an advantage of the strip casting apparatus of the present invention is that metal strips can be continuously cast having substantially uniform dimensions and substantially uniform quality over their entire length. Another advantage of the present invention is that the nozzle structure of the strip casting apparatus allows rapid and efficient casting of metal strip with minimal metal swirl during casting. SUMMARY OF THE INVENTION An object of the present invention is to provide a strip casting apparatus capable of reproducing an effective strip casting operation. Another object of the invention is to provide a strip casting apparatus which allows sufficiently rapid cooling of the produced strip to obtain an amorphous strip. The apparatus of the present invention can also continuously cast crystalline materials. Another object of the present invention is to disclose various design and dimensional requirements, in particular the nozzle construction which allows metal strips of uniform dimensions and quality to be continuously and reproducibly rapidly cast. Embodiments and drawings illustrating the present invention will be described. FIG. 1 shows an apparatus for casting metal strip 10 according to the invention. This apparatus casts the strip 10 onto a casting drum, hoop, belt, etc. In the preferred embodiment, the continuous strip 10 is cast onto a cylindrical drum or smooth outer circumferential surface 14 as shown in FIG. It can also have a shape other than circular. For example, it can also be a cast ring with a smooth frustoconical outer circumferential surface. For example, a belt rotating in an approximately elliptical path can also be used as the casting element. Whatever shape is used, the casting surface 14 is cooled below the solidification temperature of the cast metal and has a width equal to or greater than the width of the strip to be cast. In a preferred example, cast element 12 is a water-cooled, deposit-hardened copper alloy ring containing about 98% copper and about 2% chromium. Copper and copper alloys are suitable because of their high thermal conductivity and wear resistance, but beryllium copper alloys, steel,
Brass, aluminum, aluminum alloys, etc. may be used alone or in combination. For example, the outer peripheral surface of the assembled cast ring is made of a sleeve made of a material such as molybdenum. Similarly, cooling media other than water can be used. Water is cheap and easy to use. In operation of the strip casting apparatus of the present invention, the casting surface 14 of the casting wheel or casting element 12 must absorb the heat generated by contact with the molten metal at the initial casting point 16, which heat is transferred during the rotation of the casting wheel 12. need to be sufficiently transmitted to the inside of the ring. first casting point 1
6 is a position where the molten metal 20 flowing from the tundish 22 contacts the casting surface 14. Cooling by thermal conduction is achieved by supplying a sufficient amount of water to the internal passages near the outer circumferential surface of the casting wheel 12. Alternatively, the cooling medium can also be supplied directly to the underside of the contact surface.
Refrigeration techniques may also be used to accelerate or slow the cooling rate and/or control expansion and contraction of the casting wheel between castings. Whether using drums, wheels, or belts for casting, the casting surfaces are smooth and symmetrical to maximize strip casting uniformity. For example, in some strip casting operations, the spacing between the outer casting surface 14 and the surface defining the orifice passage of the nozzle for supplying molten metal to the casting surface must be maintained at a required set point during casting. This dimension is referred to as the standoff dimension or gap. This gap must remain approximately the same throughout the gold casting operation when casting uniform strips. When casting is carried out on a casting element 12, such as a drum or wheel, the rotating bodies are carefully constructed so that no circular deviations occur between revolutions and a uniform strip is cast. Experimentally, the deviation of the circle of the drum or ring is approximately
If it is more than 0.020in (approximately 0.5mm), it will cause dimensional instability, and if it is not corrected during operation, it will be rejected. To maintain dimensional symmetry and eliminate porosity in the welds, the drum or ring is manufactured from a one-piece slab of cold rolled or wrought copper alloy. Thrubs, coatings, etc. may also be used. The molten metal 20 cast by the apparatus of the present invention is held in a tundish 22 having a nozzle. In the illustrated example, the nozzle is located at the lower part of the tundish. As will be described later, the nozzle is a curved element 24 attached to a tundish 22. The curved element 24 forms part of the lower portion of the tundish and is shown in FIGS. As shown in the figure, the orifice passage 30 is located approximately at the center of the curved element 24. By locating the orifice passageway or slot 30 in a substantially central position, the pressure of the molten metal acts substantially evenly and maintains substantially equal pressure during casting.
It is also possible to have the slot in a position other than the center. The longitudinal dimension of orifice passage 30 is approximately equal to the width of the strip to be cast. The longitudinal dimension of the orifice passage is not limited, and is 36 inches (approximately 900 inches).
mm) or larger, and the curved element can have corresponding dimensions. The uniformity of the melt flow through the orifice passages 30 of the curved elements 24 results in uniform, high quality strips. To produce strips of various widths according to another embodiment, a plurality of longitudinal orifice passages 30 are cut into the curved element 24 to form the nozzle of the tundish 22. Regardless of the size of the orifice passage 30,
The cross-sectional dimensions of the orifice passages 30 are made equal along their entire length to provide a uniformly sized strip.
In operation of the strip casting apparatus of the present invention, the cooled casting surface 14 passes in front of the orifice passage 30.
It runs approximately perpendicular to the longitudinal axis of orifice passageway 30. As shown in FIG. 4, an orifice passageway 30 is formed between a first side 32 and a second side 34 of curved element 24. The first side 32 is the downstream position of the orifice passageway 30 with respect to the direction of movement of the casting surface indicated by the arrows in FIG. First side 32 has a generally planar inner surface 36 and an outward lip projecting surface 38 that faces casting surface 14 . Downstream of the orifice passageway 30, the protruding surface 38 forms a step 40 to form a lip protrusion 42. The second side 34 is upstream of the orifice passageway 30 with respect to the direction of movement of the casting surface 14 as indicated by the arrow in FIG. The second side 34 has a generally planar inner surface 46 on the first side.
is formed opposite the inner surface 36 of the side 32 of at least the orifice passage 30 with respect to the direction of flow of molten metal from the tundish 22 through the orifice passage 30.
They are almost parallel at the exit part of 0. A bottom surface 48 of second side 34 faces casting surface 14 . The standoff distance or distance h in FIG. 4 is important for good casting of the strip material.
In particular, it has been found that the distance h between the protruding surfaces 38 is more important than the distance h between the bottom surfaces 48 of the second side portion 34. This raised surface 38 is formed by providing a section 40 in the curved element 24, which step allows the nozzle to be brought sufficiently close to the casting surface without adversely affecting the strip being cast. possible. That is, the step 40 minimizes contact between the strip being cast and the nozzle so as not to adversely affect the top surface of the strip. In accordance with a preferred embodiment, the outward lip projecting surface 38 of the first side 32 and a portion of the bottom surface 48 of the second side 34 are completely parallel to the downwardly moving casting surface 14. . To make the abrasive curved elements 24 almost perfectly parallel when using a casting drum or wheel, place abrasive paper or the like on the casting surface 14 to smooth the rough surface of the curved elements 2.
Install it facing 4. By moving the curved surface element 24 and bringing it into close contact with the casting surface 14 via the abrasive paper, and rotating the casting surface and the abrasive paper, the lip protruding surface 38 of the first side 32 and the bottom surface 48 of the second side 34 are formed. At the same time, it is polished by the rough surface of the abrasive paper and becomes almost completely parallel to the casting surface 14. This parallel formation can also be achieved for most refractory nozzles when using curved cast surfaces, such as convex surfaces. To obtain parallelism with this method, 400 or 600 grit abrasive paper is suitable. By keeping a portion of the outer lip projecting surface 38 perfectly parallel to the casting surface 14, the projecting surface 38
The gap h between the casting surface 14 and the casting surface 14 is equal over the entire length of the protrusion 42. The gap h between the outer lip projecting surface 38 and the casting surface 14 should be less than about 0.120 inches (about 3 mm) to allow effective strip casting. Preferably, the gap h is less than about 0.080 inch (about 2 mm), with a gap h of less than 0.01 inch (about 0.25 mm) being suitable for casting some alloys into thin strips.
Furthermore, the gap h at the bottom surface 48 of the second side portion 34
It seems that there are no strict dimensional limitations. Preferred limitations for the second side 34 are such that the inner surface 46 extends toward the casting surface 14 and is parallel to the inner surface 36 of the first side 32 at least in the exit portion of the orifice passageway 30, such that the molten metal has a curved surface. Maintaining a steady flow through the orifice passageway 30 of the element 24 to the moving casting surface 14 is avoided. Therefore, the bottom surface 48 of the second side 34 is approximately 0.002 inches (0.05 inches) away from the casting surface 14 as shown in FIG.
mm) or the bottom surface 48 may be tapered away from the orifice and away from the casting surface, resulting in the configuration shown in FIG. In either case, the gap h between the bottom surface 48 of the second side 34 and the casting surface 14
The gap should be sufficiently narrow at the nozzle part to prevent the molten metal from flowing backward during casting. In the embodiment shown in FIG.
, and does not have the sharp 90° bend shown in Figure 4.
Curved corners 50 are used in the manufacture of some strip materials.
is advantageous. The curved corners 50 minimize swirling of the molten metal during strip casting to provide uniform production. In practice, sharp corners between the inner surface 36 and the outer lip protruding surface 38 create pressure changes and flow pattern changes that create stress concentrations in the curved element 24 and cause breakage, cracking, and wear during casting. This will harm the uniform strip casting operation. If the curved surface portion 50 is formed, adverse effects such as swirling of the molten metal flow passing through the curved surface element 24 forming the nozzle of the tundish 22 will not occur. A step or taper is formed in the interior of the orifice passageway 30 to further reduce swirl during strip casting. As shown, the inner portions of the first side 32, second side 34 are V-shaped or even curved to provide a funnel-like shape to increase the uniformity of the metal flow pattern and eliminate irregularities within the strip casting. Minimize currents and vortices. In another preferred embodiment, the curved element 24 is at an angle with the casting surface 14 to feed the molten metal in the same direction as the casting surface to reduce swirling of the molten metal during strip casting. For this purpose, the orifice passage 30 formed by the inner surfaces 36 and 46 must be aligned with the casting surface.
An angle less than 90°, preferably 45°. With this configuration, the direction of flow of the molten metal does not change abruptly compared to the case where the orifice passage 30 is perpendicular to the casting surface 14. The crucible or tundish 22 is made of a highly insulating material. When insulation is insufficient, auxiliary heaters, such as resistive elements such as induction coils or wires mounted in and/or around the tundish 22, are used to maintain the molten metal at a relatively constant temperature.
An advantageous material for the tundish is an insulating board made of fibrous kaolin, a natural high-purity alumina-silica refractory. This insulating material is commercially available under the trade name Kao Wool HS Board. For long-term use or for casting high melting point alloys, various other materials may be used to form the tundish 22, curved element 24.
Manufacture. For example, graphite, alumina graphite, quartz, clay graphite, boron nitride, silicon nitride, silicon carbide, boron carbide, alumina,
zirconia, various combinations or mixtures thereof. These materials can be reinforced. For example, fibrous kaolin is strengthened by impregnating it with silica gel or the like. The orifice passage 30 of the curved element 24 must remain open and substantially stable in shape during strip casting. If the orifice passage becomes corroded or clogged,
The primary objective of maintaining uniformity during strip casting and reducing metal flow swirl within the tundish 22 is compromised.
Because of this, some insulating materials do not maintain dimensional stability over long casting periods. In order to avoid this problem, the orifice passage 30 of the curved surface element 24
The side portions 32, 34 that form the wafer are made of a material that is dimensionally stable and maintains its integrity when exposed to high melt temperatures for extended periods of time. This material is formed into a one-piece, generally semicircular curved element 24, and a slot 30 is cut out and shaped as in FIG. The curved element 24 can also be held in the tundish as two opposing inserts with a slot 30 in between, resulting in the configuration shown in FIG. In a preferred example, the integral curved element 2
No. 4 orifice passage 30 is cut using ultrasonic waves to accurately form the required slot size. The material for the curved surface element may be a molten metal resistance material such as quartz, graphite, clay graphite, boron nitride, alumina graphite, silicon carbide, stabilized zirconia silicate, zirconia, magnesia, or alumina. The curved element 24 is held mechanically within the tundish 22 or bonded with various refractory cements. The drive and housing of the casting surface 14, such as a drum, wheel, etc., is of rigid construction to avoid drum slippage or vibration from structural instability during drum rotation. In particular, care must be taken to avoid natural frequencies at the working speed of the casting surface. The linear velocity of the casting surface is approximately 200
~10000ft/min (approximately 60~3000m/min). If the outer circumference of the drum is approximately 8 ft (approximately 2.4 m), this speed will be approximately 25 to 1250 rpm as the drum rotation speed. 3HP variable speed reversible dynamic braking motor with integrally cast copper alloy drum 2in (approx. 50mm thick) outer circumference approx. 8ft (approx. 2.4cm)
m) is suitably driven. In some embodiments, the casting surface 14 of the ring or drum of the apparatus of the invention is smooth. In some cases, the outer circumferential surface 1 of the cast element 12, for example in the case of an amorphous material.
Finish step 4 with 400- to 600-grit abrasive paper to improve the uniformity of the product. In the embodiment shown in FIG.
is made of a green-proof board, for example, Kao Wool HS board (trade name), and the curved surface element 24 is held in the wall of the tandem tray 22 as a molten metal resistant material made of clay graphite. The orifice passage 30 is cut into the clay graphite element 24 by ultrasonic machining. An orifice passageway 30 is formed between a first side 32 and a second side 34 of the curved element. In another embodiment, the curved element 24 is a plate of quartz or Vycor glass, a material that is highly resistant to molten metal, and has a width of about 0.5 inches.
(approximately 37 mm) to the required small radius as shown in the diagram. In another embodiment, curved element 24 is cast boron nitride. The slot forming the orifice passage 30 in the curved element 24 is precisely cut out using an ultrasonic drill. The integral curved element 24 shown in Figures 2, 3 and 4 is fabricated from a semicircular ring of melt resistant material. In this example, the slot width b is the parallel inner surface 36,
Approximately 0.010 to 0.080in (approximately 0.25 to 2mm) between 46 and
The claygraphite insert material is formed by ultrasonic machining and the insert is installed in the tundish 22 as shown in FIG. The outer edge of the curved element nozzle can also be shaped as desired to strengthen retention of the curved element 24 within the walls of the tundish 22. The shape of the orifice passage 30 formed in the curved surface element 24 of the present invention is shown in the enlarged cross-sectional view of FIG. According to an embodiment of the invention, the limits of the dimensions shown in FIG. 4 are as follows.

[Table] For manufacturing amorphous strips, the width b of the orifice 30 is usually about 0.010 to 0.040 inches (about 0.25 to 1
mm) range. For crystalline strip materials, such as stainless steel, the width b of the orifice passageway 30 will be greater than the values noted above, up to about 0.080 inches wide to uniformly produce thick strips. The thickness e of the curved surface element 24, the width f of the relief at the top of the orifice passage 30, and the depth g of the relief at the top of the orifice passage 30 can be determined arbitrarily. The relief dimensions f and g at the top of the orifice passage 30 are the fourth
As shown in the figure, the main purpose is to prevent molten metal from clogging in the orifice. To minimize and avoid swirling during strip casting, the sharp edges of the nozzle in the casting direction are curved.
The curved surface portion at this corner, for example, the curved surface 50 shown in FIG.
It can also be made of board or the like and formed by natural corrosion during strip casting. As shown in FIG. 5, vortices can be prevented by having the corners 50 of the protrusion 42 on the first side 32 of the curved element 24 be completely curved. During operation of the casting apparatus of the present invention, molten metal is supplied to the heated tundish 22. induction coil,
A heater, such as a resistance wire, is installed in and around the tundish 22 to maintain the desired relatively constant melt temperature. You can also pour the molten metal into a preheated tandice. The preheating temperature is set to a temperature that can prevent solidification or clogging in the orifice passage during the initial casting operation, and after this, the molten metal flow maintains the tundish 22 and the curved element 24 forming the nozzle at the required temperature, and maintains a steady flow through the orifice passage 30. Make sure to form a flow. If necessary, the curved surface element 24 is externally heated during casting. Furthermore, even if the molten metal supplied to the tundish 22 is overheated and some temperature loss occurs, the flow of the molten metal through the orifice passage 30 is not adversely affected. Additionally, the height of the riser within the tundish 22 is maintained at a relatively constant level. Normal orifice passage 30 top
10 inches (approximately 250 mm) or less to maintain a relatively constant static pressure on the orifice passageway 30 during the entire casting. For this purpose, molten metal 20 is first injected into the tundish 22 to reach the required height, and additional molten metal 20 is sequentially injected into the tundish 22 to maintain the required static pressure. The rate at which molten metal is added to the tundish 22 corresponds to the rate at which the metal flow from the orifice passageway 30 flows to the casting surface 14 to form the strip 10. Maintaining the melt height within the tundish 22 maintains a constant melt flow pressure through the orifice passageway 30 and prevents adverse effects on the casting operation and properties of the strip 10. External pressure can also be applied to control the pressure in the orifice passageway 30. As an example of implementation, the tundish tray 2 shown in FIG.
2 was made of a commercially available tundish material under the trade name Garnetx, and was cast from standard 304 stainless steel.
The orifice passage 30 at the base of the tundish is approximately 1.3 inches (approximately 21 mm) long and 0.08 inches (approximately 2 mm) wide, with a gap between the outer lip protruding surface 38 and the casting surface 14 of 0.02 to 0.2 mm.
It was set to 0.04in (approximately 0.5 to 1.0mm). The water-cooled copper alloy drum rotates at a linear speed of approximately 930 ft/min (approximately 280 m/min)
The molten metal was injected into the tundish 22 at a temperature of 2900° (approximately 1600°C) as measured by an optical pyrometer. The height of the riser was maintained at approximately 6 inches (approximately 150 mm) during casting. The manufactured strips were approximately 0.006 to 0.008 inches (approximately 0.15 to 0.2 mm) thick and exhibited as-cast strength, toughness, and passability properties. During the casting of the strip, the strip 10 is exposed to the casting surface 14 a relatively long distance, such as several feet (approximately 1
m) A tendency to maintain adhesion from the first casting point 16 was observed. If the strip 10 were attached to the cast element 12 for a full rotation, it would damage the tundish 22, particularly the orifice passage 30 of the curved element 22. Peeling can be facilitated by attaching a doctor blade, such as a knife-shaped element, to the casting surface 14 at a position of 2.5 to 6 ft (approximately 0.8 to 1.8 m) from the orifice. In this embodiment, the cast strip is inserted into the cast element 12.
It was peeled off with a doctor blade. This doctor blade is particularly useful in casting thin amorphous strip materials, which have greater adhesion than crystalline strip materials. It is believed that the force holding the strip to the casting surface reflects the strength of the thermal contact between the strip 10 and the casting surface 14. Other arrangements may also be used to separate the strip 10 from the cast element 12, such as using an air knife. Relatively high quality strips of amorphous materials, such as materials containing at least 25% amorphous in the present invention, can be cast with the casting apparatus of the present invention. Compared to a crystalline strip of the same thickness, a higher rate of quenching is required to achieve amorphousness. To increase the cooling rate, for example, the speed of the casting surface 14 is increased. This method can be performed in two effective modes. If the orifice passageway 30 is brought very close to the casting surface, as measured between the outer lip protruding surface 38 and the casting surface 14, it will be approximately 0.001 to 0.003 in.
Crystalline or crystalline materials can be cast in thicknesses of . If the outwardly protruding lip surface 38 of the first side 32 of the curved element 24 is moved away from the casting surface 14 and the casting surface speed is reduced, a strip with a thickness of 0.005 to 0.050 inches can be cast. can. The quench rate is significantly lower in this mode, due in part to the increased thickness of the product. Although the present invention has been described with reference to preferred embodiments, the present invention is capable of many modifications, and the embodiments are intended to be illustrative and not to limit the invention.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view of the continuous strip casting apparatus of the present invention, FIG. 2 is a partially enlarged sectional view of the nozzle of the apparatus shown in FIG. 1, and FIG. 3 is a perspective view of a curved element forming the nozzle. FIG. 4 is a partially enlarged sectional view of the orifice passage of the nozzle shown in FIGS. 2 and 3, FIG. 5 is a partially enlarged sectional view of the orifice passage of another embodiment, and FIG. 6 is a partially enlarged sectional view of the orifice passage of another embodiment. 7 is a partially enlarged view of an orifice passage in another embodiment, and FIG. 8 is a partially enlarged sectional view of an orifice passage in another embodiment. 10: strip, 12: casting element, 14: casting surface, 16: casting point, 20: molten metal, 22: tundish, 24: nozzle (curved element), 30: orifice passage, 32: first side, 36, 46:
Inner surface, 38: outward lip protrusion surface, 42: lip protrusion, 48: bottom surface, 50: curved surface.

Claims (1)

[Scope of Claims] 1. A continuous metal strip casting apparatus comprising: a tundish for receiving and holding molten metal; a nozzle comprising a curved element attached to the tundish;
a cooled casting surface having a width equal to or greater than the width of the strip to be cast; an orifice passage is provided in the curved element, the length of the orifice passage being approximately equal to the width of the strip to be cast, and the orifice passage extending in the longitudinal direction; The casting surface has approximately uniform cross-sectional dimensions throughout; the casting surface is movable across the orifice passageway in a direction approximately perpendicular to the longitudinal axis of the orifice passageway, such that the casting surface is no more than 0.120 inches (3 mm) from the nozzle; is formed between a first side and a second side of the curved element, said first side having a generally flat inner surface with respect to the orifice passageway and having an outer lip at the discharge end of the orifice passageway. A strip casting apparatus characterized in that the outer lip protruding surface is stepped to form a lip protrusion after the protruding surface faces the casting surface for a length of at least 0.1 inch (0.25 mm). 2. The method according to claim 1, wherein the second side has a substantially flat inner surface facing the inner surface of the first side at least in the lower part of the orifice passage, and a bottom surface facing the casting surface. Device. 3. The device according to claim 1, wherein the orifice passage is located approximately at the center of the curved element. 4 The speed at which the casting surface moves in front of the nozzle is set at a linear velocity of 200 to 10,000 ft/min (60 to 3,000 m/min).
2. The device according to claim 1, wherein the device has a minimum of 100 min). 5 The speed at which the casting surface moves in front of the nozzle is set at a linear velocity of 1800 to 4000 ft/min (540 to 1200 m/min).
2. The device according to claim 1, wherein the device has a minimum of 100 min). 6 an inner portion of an orifice passage formed between an inner surface of the first side portion and an inner surface of the second side portion;
3. The device according to claim 2, wherein the nozzle tapers inward from the molten metal holding portion toward a portion where both inner surfaces are parallel to each other. 7. Between the outer lip protruding surface and the casting surface.
The device according to claim 1, wherein the diameter is 0.080 in (2 mm) or less. 8 At least on the outer lip protruding surface and the casting surface.
2. The device of claim 1, wherein the lip protrusion is formed by providing a stepped portion after facing each other over a length of 0.02 inches (5 mm). 9. The device of claim 1, further comprising an integrally formed curved surface between the inner surface of the first side and the outwardly projecting surface of the first side. 10. The apparatus according to claim 2, wherein the distance between the bottom surface of the second side portion and the casting surface is 0.080 inches (2 mm) or less. 11. The device according to claim 1, wherein the casting surface is formed on the outer circumferential surface of a water-cooled rotary ring. 12 The rotating wheel is made of copper, copper alloy, aluminum,
12. The device of claim 11 made of a metal selected from the group consisting of aluminum alloys, steel, molybdenum and combinations thereof. 13. The apparatus of claim 1, wherein at least a portion of the outward lip projecting surface is completely parallel to the opposing casting surface. 14. The apparatus of claim 2, wherein at least a portion of the bottom surface of the second side is completely parallel to an opposing casting surface. 15. The apparatus according to claim 13, wherein the distance between the casting surface and the outwardly protruding surface of the parallel first side is 0.025 inches (0.63 mm) or less. 16. The apparatus according to claim 13, wherein the distance between the casting surface and the outwardly protruding surface of the parallel first side is 0.01 inch (0.25 mm) or less. 17 The distance between the casting surface and the outward lip protruding surface of the opposing parallel first side is 0.003 to 0.006 inch (0.08 inch).
14. The device according to claim 13, wherein the diameter is within the range of 0.15 mm). 18 The distance between the parallel inner surfaces forming at least the outer portion of the orifice passage is 0.010 to 0.035 inches.
(0.25 to 0.89 mm). 19 Between the bottom surface of the second side part and the casting surface
The device according to claim 2, which maintains the distance below 0.002 inches (0.05 mm). 20. The apparatus of claim 2, wherein both inner surfaces forming the orifice passage form an angle of less than 90° with respect to the casting surface. 21. The device according to claim 2, wherein both inner surfaces forming the orifice passage are at an angle of 45° with respect to the casting surface. 22 The curved surface element is selected from the group consisting of graphite, aluminagraphite, claygraphite, quartz, fibrous kaolin, boron nitride, silicon nitride, silicon carbide, boron carbide, alumina, zirconia, stabilized zirconia silicate, magnesia, and combinations thereof. 2. A device according to claim 1, manufactured from a material selected from: