Nozzle Tip Design for High-Performance Continuous Casting

Abstract

A nose tip for continuous casting of a metal alloy is described. The nose tip may include a first portion having a first surface parallel to a second surface, the second surface facing the first surface. The nose tip may include a second portion having a third surface oriented toward the extended first surface. The extended first surface may be in a common plane with the first surface. The nose tip may include a third portion having an arcuate surface connecting the third surface to the extended first surface. The arcuate surface may include a point of curvature at a vertical distance from the extended first surface. The vertical distance may be configured to limit a maximum meniscus height between the nose tip and the continuous casting surface for liquid metal cast using the nose tip. A method of continuous casting of a metal alloy at a casting speed of greater than 12 m / min is also described.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit and priority of U.S. Provisional Application No. 63 / 195,731, filed on June 2, 2021, which is hereby incorporated by reference in its entirety for all purposes.

[0002] The present disclosure generally relates to metallurgy, and more specifically, to the continuous casting of alloy products using a continuous casting apparatus.

Background Art

[0003] Techniques for manufacturing metal strip articles, such as metal strips, slabs, or plates, may include using a continuous casting apparatus. For example, aluminum alloy strip products may be cast using continuous casting. Using a specific continuous casting apparatus such as a belt caster, the liquid metal can be solidified as it passes between the moving cooling surfaces of the continuous casting apparatus. These systems typically have limitations on how fast a metal strip can be continuously cast while achieving an acceptable surface quality.

Summary of the Invention

[0004] The terms "embodiment" and like terms are intended to broadly refer to all of the subject matter of the present disclosure and the following claims. Descriptions that include these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the following claims. Embodiments of the present disclosure addressed herein are not an abstract of the invention, but are defined by the following claims. The abstract of the invention is a general overview of various aspects of the present disclosure and introduces some of the concepts further explained in the section on modes for carrying out the invention below. The abstract of the invention is not intended to identify important or essential features of the subject matter recited in the claims, nor is it intended to be used alone to determine the scope of the subject matter recited in the claims. The subject matter should be understood by reference to the entire specification of the present disclosure, any or all of the drawings, and the appropriate portions of each claim.

[0005] In one aspect, a nozzle tip for continuous casting of a metal alloy is described. The nozzle tip of this aspect may include a first portion having a first surface parallel to a second surface. The second surface may face the first surface. The nozzle tip may include a second portion having a third surface directed toward the extended first surface. The extended first surface may be in a plane common with the first surface. The nozzle tip may include a third portion having an arcuate surface connecting the third surface to the extended first surface.

[0006] In an example, the arcuate surface may include a bending point. The bending point may be a vertical distance from the extended first surface. The vertical distance may be configured to limit the maximum meniscus height with respect to the liquid metal cast using the nozzle tip between the nozzle tip and the continuous casting surface.

[0007] In an example, the third portion of the nose tip may include a turbulent flow generating mechanism. The turbulent flow generating mechanism may be at least one selected from a plurality of depressions, a plurality of ribs, a plurality of piers, or a surface roughness greater than the surface roughness of the first surface, the second surface, or the extended first surface.

[0008] In an example, the nose tip may include a refractory material. In some cases, the nose tip may include a material coated with a non-wetting substance such as boron nitride (BN).

[0009] In another aspect, a method for continuous casting of a metal alloy is described. The method of this aspect may include providing an arcuate nose tip. The arcuate nose tip may include a first portion having a first surface parallel to a second surface, where the second surface faces the first surface, a second portion having a third surface directed toward the extended first surface, where the extended first surface is in the same plane as the first surface, and a third portion having an arcuate surface connecting the third surface to the extended first surface. The method may include flowing liquid metal through the arcuate nose tip into a casting cavity to form a casting.

[0010] In an example, the method may include that the meniscus length of the liquid metal flowing through the arcuate nose tip is at most equal to the distance from the inflection point to the casting surface that partially defines the casting cavity. In some examples, the meniscus length may be 0.5 mm to 2.0 mm.

[0011] In an example, the third portion of the arcuate nose tip may further include a turbulent flow generating mechanism. The turbulent flow generating mechanism may be at least one selected from surface roughness, a plurality of depressions, a plurality of ribs, a plurality of piers, and combinations thereof.

[0012] In an example, the method may further include using magnetic vibration technology to generate turbulent flow in the liquid metal at the arcuate surface.

[0013] In an example of this method, the nozzle tip may include a refractory material.

[0014] In the example, the surface roughness of the casting may be at most 10 μm. The surface roughness may be measured, for example, by 3D image analysis. The composition near the surface of the casting may have a decrease in Fe and Mn at the casting surface compared to a reference conventional casting standard. The composition may be characterized by glow discharge optical emission spectrometry. The casting may have a leachate frequency of at most 30 leachates / cm 2 and may be determined, for example, by 3D image analysis.

[0015] In the example, the disclosed method is useful for casting at a rate exceeding 12 m / min.

[0016] Other objects and advantages will be apparent from the following detailed description of non-limiting examples.

[0017] This specification refers to the following accompanying drawings. In the accompanying drawings, when like reference numerals are used in different figures, it is intended to illustrate like or similar components.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6

DETAILED DESCRIPTION OF THE INVENTION

[0019] This specification describes a nose tip for continuous casting. The nose tip includes an arcuate surface and optionally a turbulence mechanism. Also described herein are methods of casting using the nose tip and products formed from aluminum alloys cast using the nose tip. The disclosed nose tip is also referred to herein as an arcuate nose tip in the same sense. The disclosed nose tip includes an arcuate surface with a curvature point that defines the maximum height (or distance from the belt) to which the meniscus can extend. The disclosed nose tip is an improvement over nose tips such as nose tip 100 shown in FIG. 1. In FIG. 1, nose tip 100 is shown in a partial cross-sectional schematic view including a bow-shaped portion having a cutback. By the disclosed arcuate nose tip, the meniscus height is reduced, thereby increasing the stability of the flow of liquid aluminum. By increasing the stability of the flow, surface defects in the casting are reduced and a higher casting speed can be achieved. The amplitude of meniscus vibrations occurring during casting can be reduced to improve heat removal. With improved consistency in heat removal, surface defects are reduced. The increase in casting speed is brought about by limiting surface defects without generating an unstable meniscus vibration region.

[0020] As shown in FIG. 1, a nozzle tip example 100 for a continuous casting machine includes a bow-shaped portion 120. Liquid metal 152 separates from the nozzle tip 100 at the bow-shaped portion, where a gas / liquid interface meniscus 150 is formed. The bow-shaped portion 120 includes a cutback that angles with respect to a vertical line L perpendicular to the belt B, ensuring that the meniscus vibrates at a constant interval and does not intermittently adhere to the surface of the nozzle tip 100. This adhesion can cause nozzle tip material / oxide reactions and non-uniform surface appearance. The cutback provides a single point of contact, and the meniscus height extends to the tip of the bow-shaped portion. The liquid metal meniscus 150 is formed during casting and extends to the height H of the bow-shaped portion. Direction D indicates the direction in which the decomposed release agent escapes through the space between the nozzle tip 100 and the belt B.

[0021] In a conventional continuous casting apparatus, it may be difficult to produce a desirable surface of a cast metal article. Surface defects can result in waste (e.g., when the cast metal article cannot be used) or the need for further downstream processing (e.g., to correct or mitigate any modifiable surface defects). Also, conventional configurations limit the casting speed. For example, the conventional casting speed is limited to a maximum of 12 m / min. A casting speed of 12 m / min means that the cast product exits the casting apparatus in the casting direction at a speed of 12 m per minute. The nozzle tip of the present disclosure can increase stability during casting by reducing the meniscus height, resulting in a metal article with fewer defects, more uniform heat removal, a faster casting speed, and a greater production throughput.

[0022] Definitions and Explanations As used herein, the terms "invention," "the invention," "this invention," and "the present invention" are intended to broadly refer to the subject matter of this patent application and all of the following claims. It should be understood that descriptions containing these terms neither limit the subject matter described herein nor the meaning or scope of the following claims.

[0023] As used herein, the terms "upper" and "lower" can be associated with the vertical position when the continuous casting apparatus is casting in the horizontal direction. However, in some cases, the continuous casting apparatus may be used in a non-horizontal direction, and in this case, the terms "upper" and "lower" may refer to positions within a plane perpendicular to the casting direction of the continuous casting apparatus.

[0024] A continuous casting machine or continuous casting apparatus can include a pair of opposing cooling assemblies that form a casting cavity therebetween. In some cases, additional features such as side dams can further define the extent of the casting cavity. Each cooling assembly can include at least one cooling surface for extracting heat from the liquid metal within the casting cavity, as well as additional equipment associated with the operation of the cooling surface or the cooling assembly (e.g., cooling pads, motors, refrigerant piping, sensors, and other similar equipment).

[0025] Some continuous casting machines, such as belt casters, can include two counter-rotating belts (e.g., opposing cooling surfaces) that form a casting cavity for supplying liquid metal, together with side dams. The belts can be water-cooled (e.g., cooled with deionized water) or can be cooled using other fluids. Liquid metal entering the casting cavity from the inlet of the casting cavity can solidify through heat extraction via the cooled belts as it moves distally toward the outlet of the casting cavity, and exits at the outlet as solidified metal (e.g., a continuous casting article). Since the metal can move through the casting apparatus at approximately the same speed as the movement speed of the belts, the shear force between the solidifying metal and the belts is minimized or eliminated. Cooling pads can be utilized for the control of casting. The cooling pads can include a plurality of nozzles arranged in a pattern, such as a hexagonal pattern or other pattern, along the surface of the cooling pads. In some cases, the cooling pads can include at least one linear nozzle that extends across the width of the cooling pad and / or substantially or completely across the width of the casting cavity.

[0026] In this description, reference is made to alloys identified by AA numbers such as "system" or "7xxx" and other related designations. To understand the numbering system most commonly used when naming and identifying aluminum and its alloys, reference should be made to "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" or "Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot" (both published by The Aluminum Association).

[0027] As used herein, plates generally have a thickness greater than about 15 mm. For example, a plate may refer to an aluminum product having a thickness greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm.

[0028] As used herein, sheets (also referred to as sheet plates) generally have a thickness of about 4 mm to about 15 mm. For example, a sheet may have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

[0029] As used herein, sheets generally refer to aluminum products having a thickness less than about 4 mm. For example, a sheet may have a thickness less than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1 mm, less than about 0.5 mm, or less than about 0.3 mm (e.g., about 0.2 mm).

[0030] As used herein, the terms "cast aluminum alloy product", "cast product", "cast aluminum alloy article", "cast article", etc. are interchangeable and can refer to products made by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting, electromagnetic casting, hot top casting, or any other casting method, but in this specification, in particular, refers to products made by continuous casting (including those by use of a double belt caster, double roll caster, block caster, or any other continuous caster). The cast articles described herein can be processed by any means known to those skilled in the art. Such processing steps include, but are not limited to, homogenization, hot rolling, cold rolling, solution heat treatment, and optional pre-aging steps.

[0031] Aluminum alloy products including strips, slabs, sheets, sheaths, or plates formed using the continuous caster with the arc-shaped nose tip described herein can be used in automotive applications and other transportation applications (including aircraft and railway applications). For example, using the disclosed aluminum alloy products, automotive structural and formed parts can be prepared, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (e.g., A-pillars, B-pillars, and C-pillars), inner panels, outer panels, side panels, inner hoods, outer hoods, or trunk lid panels. Also, the aluminum alloy products and methods described herein can be used in aircraft or railway vehicle applications to prepare, for example, outer and inner panels.

[0032] The aluminum alloy products and methods described herein can also be used in applications for electronic devices. For example, the aluminum alloy products and methods described herein can be used to prepare housings for electronic devices including mobile phones and tablet computers. In some examples, aluminum alloy products can be used to prepare housings for mobile phones (e.g., smartphones), tablet bottom chassis, and external casings of other portable electronics.

[0033] The aluminum alloy products and methods described herein can be used in any other desired applications.

[0034] All ranges disclosed herein are to be understood to encompass all sub-ranges subsumed therein. For example, the recited range "1 to 10" should be considered to include all sub-ranges between the minimum value 1 and the maximum value 10 (and including these). That is, all sub-ranges start with a minimum value of 1 or more (e.g., 1 to 6.1) and end with a maximum value of 10 or less (e.g., 5.5 to 10). Unless otherwise stated, the expression "up to" when referring to the compositional amount of an element means that the element is optional and includes zero percent composition of that particular element. Unless otherwise stated, all composition percentages are by weight percent (wt.%).

[0035] As used herein, the meanings of "a", "an", and "the" include references to both singular and plural forms unless the context clearly dictates otherwise.

[0036] Nozzle tip for continuous casting These exemplary embodiments are provided to introduce the reader to the general subject matter described herein and are not intended to limit the scope of the disclosed ideas. In the following sections, various additional features and examples will be described with reference to the drawings. In the drawings, like numerals indicate like components. Also, descriptions of direction are used to explain exemplary embodiments, but like the exemplary embodiments, should not be used to limit the present disclosure. The elements included in the examples herein may not be drawn to scale. Specifically, the angle of attack illustrated herein is exaggerated for purposes of explanation.

[0037] The present specification describes a nozzle tip for continuous casting, such as an arcuate nozzle tip. FIG. 2 is a cross-sectional or side schematic view showing a continuous casting apparatus 200 according to a particular aspect of the present disclosure. The continuous casting apparatus 200 includes an upper belt assembly 202 and a lower belt assembly 204, with a casting cavity 250 disposed therebetween. Each of the upper belt assembly 202 and the lower belt assembly 204 can include a cooling belt 208, a proximal support 210, and a distal support 212. In some cases, the proximal support 210 can be a proximal cooling pad used to extract heat from the cooling belt 208. In some cases, the distal support 212 can be a distal cooling pad used to extract heat from the cooling belt 208. When the proximal support 210 and / or the distal support 212 are not cooling pads, heat extraction from the cooling belt 208 can be achieved using other cooling elements such as refrigerant nozzles, spray bars, or any other suitable cooling element. As used herein, the term "proximal" with respect to a cooling pad, support, etc. can refer to a structure disposed at or near an entrance to the casting cavity 250, such as where the liquid metal enters the casting cavity 250. As used herein, the term "distal" with respect to a cooling pad, support, etc. can refer to a structure disposed at or near an exit of the casting cavity 250, such as where the solidified metal exits the casting cavity 250.

[0038] FIG. 2 shows a single proximal support 210 and a single distal support 212 for each of the upper belt assembly 202 and the lower belt assembly 204, although other numbers of supports or cooling pads can be used. In some cases, the proximal support 210 and / or the distal support 212 can each include a plurality of supports and / or cooling pads configured to achieve a two-stage converging profile. In some cases, additional supports (e.g., additional cooling pads) can be disposed between the proximal support 210 and the distal support 212 to provide additional stages to the converging profile, such as achieving a converging profile of three or more stages.

[0039] The belt 208 can be formed of any suitable thermally conductive material such as copper, steel, or aluminum. The belts 208 of the upper belt assembly 202 and the lower belt assembly 204 can rotate in opposite directions from each other, and the surface of the belt 208 that contacts the liquid metal 252 within the casting cavity 250 moves in the downstream direction 254. The upper belt assembly 202 and the lower belt assembly 204 can further include additional equipment such as motors and other equipment as needed.

[0040] The liquid metal 252 can enter the casting cavity 250 via the nozzle 214. Within the casting cavity 250, the liquid metal 252 can solidify as heat is extracted through the belts 208 of the upper belt assembly 202 and the lower belt assembly 204. The liquid metal 252 and the liquid metal that is in the process of solidifying move within the casting cavity 250 in the direction 254. After sufficient heat has been extracted, the liquid metal 252 becomes solid and can exit the casting cavity 250 as a continuous cast article 206. The continuous cast article 206 exits the continuous casting apparatus 200 at the exit temperature. The nozzle 214 can be at least one linear nozzle that extends across the width of the cooling pad and / or substantially or completely across the width of the casting cavity 250. The nozzle 214 can include a nozzle tip such as an arcuate nozzle tip as described herein.

[0041] The casting cavity 250 is bounded by an inlet (e.g., at the nozzle 214), an outlet (e.g., where the continuous casting article 206 exits the casting cavity 250), side dams, an upper belt assembly 202, and a lower belt assembly 204. More specifically, since the belts 208 of the upper and lower belt assemblies 202, 204 are moving, the upper and lower portions of the casting cavity 250 are bounded by the outer surfaces 256 of the belts 208 that lie between the inlet and the outlet of the casting cavity 250 at any given point in time. The path of these outer surfaces 256 can be adjusted, for example, by pushing them from within the upper and lower belt assemblies 202, 204 (e.g., from the side opposite the belts 208 from the casting cavity 250). As shown in FIG. 2, a proximal support 210 and a distal support 212 are disposed within each of the upper and lower belt assemblies 202, 204. The proximal support 210 and the distal support 212 can physically contact the belt 208 and define the path of the belt 208, and thus the path of the outer surface 256 of the belt 208. The path of the outer surface 256 of the belts 208 of the upper and lower belt assemblies 202, 204 defines a converging profile with respect to the casting cavity 250.

[0042] FIG. 3 shows a partial cross-sectional view of an example arcuate nozzle tip 300 for dispensing liquid metal 352 into a casting cavity (e.g., from the nozzle 214 of FIG. 2 into the cavity 250). The liquid metal 352 exits the nozzle tip 300, begins to fill the casting cavity, and can contact the outer surface 308 of the belt B. A meniscus atmosphere 354 fills the space above the belt B under the nozzle tip 300. A meniscus 350 is formed within the liquid metal 352 between the nozzle tip 300 and the outer surface 308 of the belt B. As the liquid metal 352 cools, it begins to solidify and continues until it becomes a solid continuous casting article (e.g., a metal strip). There is a solidification distance (not shown) between the location where the liquid metal 352 first contacts the belt B and the location where the liquid metal 352 is completely solidified or is sufficiently solidified such that little or no solidification shrinkage occurs thereafter.

[0043] The nose tip 300 can have a first portion 322. The first portion 322 has a first surface 321 that is parallel or substantially parallel to a second surface 323. The second surface 323 faces the first surface 321. The nose tip 300 has a second portion 326. The second portion 326 has a third surface 327 that faces an extended first surface 325, and the extended first surface 325 is in a common plane with the first surface 321. As shown in FIG. 3, the third surface 327 is angled in a direction toward the extended first surface 325. The third surface 327 may be angled, inclined, curved, bent, tapered, or otherwise oriented toward the extended first surface without contacting the extended first surface 325. The nose tip 300 has a third portion 330. The third portion 330 has an arcuate surface 329 that connects the third surface 327 to the extended first surface 325.

[0044] The arcuate surface 329 includes a curvature point p. The liquid metal 352 moves from this curvature point p toward the belt B. The line L extends from the point p to the outer surface 308 of the belt. The curvature point p is at a distance h along the line L from the belt B. The distance h is configured to be the maximum height with respect to the meniscus 350 and is the height of the liquid metal that should contact the nose tip 300 and the belt B.

[0045] In some examples, the arcuate nose tip of the present disclosure includes a turbulence generation mechanism. As used herein, a turbulence generation mechanism is generally defined as any mechanism that provides turbulence around a curved object. FIG. 4A shows a schematic view of a ball-shaped object having a smooth surface, and FIG. 4B shows a schematic view of a ball-shaped object having a dimpled surface. In the case of the ball-shaped object with the dimpled surface, due to the presence of turbulent vortices, the turbulent boundary layer may remain attached at a much steeper angle than a similar laminar boundary layer. Due to this effect, the flow around the ball-shaped object in FIG. 4B becomes turbulent. As a result, the flow remains attached past the upper center point on the ball-shaped object and separates only on the opposite side of the ball-shaped object. As a result, the pressure resistance on the ball-shaped object in FIG. 4B is lower than that of a comparative ball-shaped object having a smooth surface as in the case of FIG. 4A.

[0046] This concept of the influence of turbulent vortices on a ball-shaped object is applied to the arcuate nose tip of the present disclosure. In some examples, the arcuate nose tip has a third portion that includes a turbulence generation mechanism. FIG. 5 shows an improved nose tip 500 that includes a turbulence generation mechanism 520. This increase in turbulence causes the flow to adhere longer at the nose tip exit (e.g., the curvature point p), and the overall height of the meniscus formed decreases. This decrease in meniscus height improves the surface finish due to a decrease in the amplitude of meniscus vibrations. In addition to a decrease in the spacing of meniscus marks on the surface immediately after casting, this also results in a decrease in the temperature gradient within adjacent layers in the newly solidified casting surface. Surface defects such as exudates or blisters are often formed along the meniscus marks, which is thought to be due to small differences in the solidification rate in adjacent regions. By reducing the distance between meniscus marks, it is expected that the difference in solidification rate in adjacent regions will decrease and the defects formed will decrease. An increase in the casting speed is also achieved because the meniscus remains stable throughout a wider range of casting speeds. Conventional continuous casting apparatuses have been limited in casting speed due to surface defects caused by meniscus vibrations.

[0047] In some examples, the turbulence generation mechanism 520 includes, but is not limited to, at least one selected from surface roughness, a plurality of depressions, a plurality of ribs, a plurality of piers, or similar structures, and combinations thereof. In addition or alternatively, in some examples, the turbulence generation mechanism includes magnetic vibrations, such as a location where a controllable electromagnet interacts with the liquid metal at the location of the turbulence generation mechanism 520 shown in FIG. 5. By combining an arcuate nose tip with the turbulence generation mechanism, the flow of the liquid metal remains attached to the nose tip until a much steeper angle is reached, thereby reducing the meniscus length and improving stability at higher casting speeds.

[0048] Figure 5 shows a partial cross-sectional view of an arcuate nose tip 500 for distributing liquid metal 552 into a casting cavity. The nose tip 500 includes an arcuate surface 529 and further includes a turbulence generating mechanism 520 on the surface of the nose tip 500 and the like. A meniscus 550 is formed in the liquid metal 552 between the nose tip 500 of the nozzle and the outer surface 508 of the belt B. A meniscus atmosphere 554 fills the space above the belt B under the nose tip 500. As the liquid metal 552 cools, it begins to solidify and continues until it becomes a solid continuous casting article (e.g., a metal strip). The nose tip 500 includes a first portion 522. The first portion 522 has a first surface 521 parallel to a second surface 523, and the second surface 523 faces the first surface 521. The nose tip 500 has a second portion 526. The second portion 526 has a third surface 527 directed toward an extended first surface 525, and the extended first surface 525 is in a plane common with the first surface 521. As shown in Figure 5, the third surface 527 is angled in a direction toward the extended first surface 525. The third surface 527 may be angled, inclined, curved, bent, tapered, or otherwise directed toward the extended first surface 525 without contacting the extended first surface 525. The nose tip 500 has a third portion 530. The third portion 530 has an arcuate surface 529 connecting the third surface 527 to the extended first surface 525. The arcuate surface 529 includes a bending point p. The bending point p is a distance h along line L from the belt B. The distance h is configured to be the maximum height with respect to the meniscus 550 and is the height of the liquid metal that should contact the nose tip 500 and the belt. Depending on the form of the turbulence generating mechanism 520, the meniscus 550 may change in shape or length compared to that of the meniscus 350 shown in Figure 3. In one example, the turbulence generating mechanism 520 includes a plurality of depressions, but other turbulence generating mechanisms are conceivable and may be included at least partially in the arcuate surface. Examples for the turbulence generating mechanism 520 include, but are not limited to, surface roughness, a plurality of ribs, a plurality of piers, and other such structures, and combinations thereof.

[0049] Figure 6 shows a partial cross-sectional view of another nozzle tip 600 for distributing liquid metal 652 into the casting cavity. The nozzle tip 600 includes an arcuate surface 629 and a cutback 631. A meniscus 650 is formed within the liquid metal 652 between the nozzle tip 600 of the nozzle and the outer surface 608 of the belt B. As the liquid metal 652 cools, it begins to solidify and continues until it becomes a solid continuous casting article (e.g., a metal strip). The nozzle tip 600 includes a first portion 622. The first portion 622 has a first surface 621 parallel to a second surface 623, and the second surface 623 faces the first surface 621. The nozzle tip 600 has a second portion 626. The second portion 626 has a third surface 627 directed toward an extended first surface 625, and the extended first surface 625 is in the same plane as the first surface 621. As shown in Figure 6, the third surface 627 is angled in a direction toward the extended first surface 625. The third surface 627 may be angled, inclined, curved, bent, tapered, or otherwise directed toward the extended first surface 625 without contacting the extended first surface 625. The nozzle tip 600 has a third portion 630. The third portion 630 has an arcuate surface 629 connecting the third surface 627 to the cutback 631. As illustrated, an angle of approximately 15 degrees with respect to a line L perpendicular to the belt B defines the cutback 631. The cutback 631 extends to the extended first surface 625 that extends within the portion 630. The arcuate surface 629 includes a curvature point p that coincides with one end of the cutback 631, and the other end of the cutback 631 intersects the extended first surface 625. The curvature point p is a distance h along the line L from the belt B. The distance h is configured to be the maximum height with respect to the meniscus 650 and is the height of the liquid metal that should contact the nozzle tip 600 and the belt.

[0050] Optionally, the portion 630 may include a turbulence generation mechanism 620 as described above. The meniscus 650 may vary in shape or length compared to that of the meniscus 350 shown in FIG. 3 or the meniscus 550 shown in FIG. 5. In one example, an optional turbulence generation mechanism 620 includes a plurality of depressions, although other turbulence generation mechanisms are contemplated and may be included at least partially in an arcuate surface. Examples for the turbulence generation mechanism 620 include, but are not limited to, surface roughness, a plurality of ribs, a plurality of pins, and other such structures, and combinations thereof.

[0051] The nozzle tips of the present disclosure, such as the nozzle tip 300 of FIG. 3, the nozzle tip 500 of FIG. 5, and the nozzle tip 600 of FIG. 6, may be formed of any refractory material that can withstand the temperature of the molten metal being cast. In some examples, the refractory material has a high surface energy to obtain excellent non-wetting properties. The arcuate shape and / or turbulence generation mechanism of the nozzle tip may be manufactured using techniques known in the art. The refractory material should not be so easily damaged, for example, so thin or brittle as to crack or develop holes, because such damage can affect the casting surface. In other examples, the nozzle tips, such as the nozzle tip 300 of FIG. 3, the nozzle tip 500 of FIG. 5, and the nozzle tip 600 of FIG. 6, may be formed of a refractory or non-refractory material and then coated with a material having a high surface energy to obtain excellent non-wetting properties. In a non-limiting example, boron nitride (BN) may be used as a coating for the nozzle tip.

[0052] Disclosed aluminum alloys and methods of manufacturing aluminum alloy products The aluminum alloys and aluminum alloy products described in this specification can be continuously cast using any suitable continuous casting method known to those skilled in the art, using the nose tips described in this specification, such as the arc-shaped nose tips 300, 500, and 600 of FIGS. 3, 5, and 6, respectively. In some examples, the nose tip includes a first portion having a first surface parallel to a second surface, where the second surface faces the first surface, a second portion having a third surface directed toward an extended second surface, where the extended second surface is in a common plane with the second surface, and a third portion having a curved surface connecting the third surface to the extended second surface, where the third portion includes a curvature point. The method further includes casting the liquid metal using an arc-shaped nose tip configured to provide a meniscus length equal to at most the distance from the curvature point to the belt. In some examples, the meniscus length ranges from about 0.5 mm to about 2 mm, such as 0.5 mm to 1.0 mm, 0.5 mm to 1.5 mm, 1.0 mm to 1.5 mm, 1.0 mm to 2.0 mm, or 1.5 mm to 2.0 mm.

[0053] Continuous casting of the aluminum alloys described in this specification can provide cast products having a surface roughness, or Ra value, that is less than that of cast products using conventional nose tips. The surface roughness may alternatively be measured as the number of defects, including the size and distribution of the defects, for example, by image analysis. In terms of the number of defects, a better representation of the surface roughness of the cast product can be obtained due to the larger sampling area, as the measurement is taken over a region where the Ra value is relatively small. Thus, if the defects are not uniformly distributed on the surface, there may be significant variations in Ra for each measurement location. In some examples, the surface of the cast products of the present disclosure has few surface defects and an Ra value of at most 10 μm, at most 5.0 μm, at most 3.5 μm, at most 2.5 μm, at most 2.0 μm, or at most 1.5 μm.

[0054] By the method described in this specification, surface defects on or near the surface of a casting can be reduced. The defects may include exudates. Exudates are surface defects caused by reheating of the region near the surface of the slab when the solidifying casting slab contracts in a direction away from the cooling surface. The density of exudates may depend on the alloy, and 6xxx alloys tend to exude more. Exudates may have a diameter of about 50 μm or less depending on the alloy. In some examples, for cast aluminum alloys, when measured by image analysis, the exudate frequency is at most 30 exudates / cm 2 is. The exudate height ranges from about 5 μm to about 100 μm. The roughness may be measured by measuring the height of the defect (exudate) by 3D imaging (Keyence).

[0055] By the method described in this specification, casting speeds exceeding 12 m / min, exceeding 14 m / min, exceeding 16 m / min, or exceeding 18 m / min can be obtained. The casting speed can be improved by up to 50 percent or more compared to the casting speed using a conventional nose tip limited to a maximum of 12 m / min.

[0056] By the casting according to the present disclosure, a composition near the surface with few defects and impurities can be obtained. The composition near the surface may be analyzed by glow discharge optical emission spectroscopy (GDOES) to obtain a measure of the elemental concentration as a function of depth. The composition near the surface may be characterized by GDOES for elemental analysis to a desired depth, such as up to a maximum of 1 μm, up to a maximum of 2 μm, up to a maximum of 5 μm, up to a maximum of 10 μm, up to a maximum of 15 μm, or greater or less than that. In conventional continuous castings, the presence of Fe and Mn on the surface of the continuous casting final gauge product and the presence of an exposed zone below the surface may occur, which is in contrast to standard direct casting processed products. This may be due to the presence of Fe and / or Mn including surface intermetallic compounds resulting from continuous casting. The composition near the surface of the casting has reduced Fe and Mn compared to a reference conventional casting standard.

[0057] In some examples, the number of surface defects including exudates in the composition near the surface is small, whereby the Fe and Mn contents in the casting surface are reduced.

[0058] Exemplary embodiments As used hereinafter, any reference to a series of embodiments (e.g., "Embodiments 1-4") or an unenumerated set of embodiments (e.g., "any preceding or succeeding embodiment") should be understood as a disjunctive reference to each of those embodiments (e.g., "Embodiments 1-4" should be understood as "Embodiment 1, 2, 3, or 4").

[0059] Embodiment 1 is a nose tip for continuous casting of a metal alloy, the nose tip comprising a first portion having a first surface parallel to a second surface, the second surface facing the first surface, the first portion, and a second portion having a third surface directed toward an extended first surface, the extended first surface being in a common plane with the first surface, the second portion, and a third portion having an arcuate surface connecting the third surface to the extended first surface.

[0060] Embodiment 2 is a nose tip of any preceding or succeeding embodiment, the nose tip wherein the arcuate surface includes a bending point.

[0061] Embodiment 3 is a nose tip of any preceding or succeeding embodiment, the nose tip wherein the bending point is a vertical distance from the extended first surface, the vertical distance being configured to limit a maximum meniscus height with respect to liquid metal cast using the nose tip between the nose tip and a continuous casting surface.

[0062] Embodiment 4 is a nose tip of any preceding or succeeding embodiment, the nose tip wherein the third portion includes a cutback between the bending point and the extended first surface.

[0063] Aspect 5 is the nozzle tip of any preceding or subsequent aspect, wherein the third portion includes a turbulence generation mechanism, and is the nozzle tip.

[0064] Aspect 6 is the nozzle tip of any preceding or subsequent aspect, wherein the turbulence generation mechanism is at least one selected from a plurality of depressions, a plurality of ribs, a plurality of piers, or a surface roughness greater than the surface roughness of the first surface, the second surface, or the extended first surface, and is the nozzle tip.

[0065] Aspect 7 is the nozzle tip of any preceding or subsequent aspect, wherein the nozzle tip includes a refractory material, and is the nozzle tip.

[0066] Aspect 8 is a method for continuously casting a metal alloy, the method including providing an arcuate nozzle tip, the arcuate nozzle tip including a first portion having a first surface parallel to a second surface, the second surface facing the first surface, the first portion, a second portion having a third surface directed toward an extended first surface, the extended first surface being in a common plane with the first surface, the second portion, and a third portion having an arcuate surface connecting the third surface to the extended first surface, the providing, and casting liquid metal through the arcuate nozzle tip into a casting cavity to form a casting, the method.

[0067] Aspect 9 is the method of any preceding or subsequent aspect, wherein the meniscus length of the liquid metal flowing through the arcuate nozzle tip is at most equal to the distance from the inflection point to the casting surface that partially defines the casting cavity, the method.

[0068] Aspect 10 is the method of any preceding or subsequent aspect, wherein the meniscus length is 0.5 mm to 2.0 mm, the method.

[0069] Aspect 11 is a method of any preceding or subsequent aspect, wherein the third portion of the arcuate nose tip further includes a turbulence generation mechanism, the method.

[0070] Aspect 12 is a method of any preceding or subsequent aspect, wherein the turbulence generation mechanism is at least one selected from surface roughness, a plurality of depressions, a plurality of ribs, a plurality of piers, and combinations thereof, the method.

[0071] Aspect 13 is a method of any preceding or subsequent aspect, further including generating turbulence in the liquid metal on the arcuate surface using magnetic vibration technology, the method.

[0072] Aspect 14 is a method of any preceding or subsequent aspect, wherein the nose tip is a refractory material, the method.

[0073] Aspect 15 is a method of any preceding or subsequent aspect, wherein the surface roughness of the casting is at most 10 μm, the method.

[0074] Aspect 16 is a method of any preceding or subsequent aspect, wherein the surface roughness is measured by 3D image analysis, the method.

[0075] Aspect 17 is a method of any preceding or subsequent aspect, wherein the composition near the surface of the casting has a decrease in Fe and Mn on the casting surface compared to a reference conventional casting standard, the method.

[0076] Aspect 18 is a method of any preceding or subsequent aspect, wherein the composition is characterized by glow discharge optical emission spectrometry, the method.

[0077] Aspect 19 is a method of any preceding or subsequent aspect, wherein the casting has a maximum leachate frequency of 30 leachates / cm 2 , the method.

[0078] Aspect 20 is the method of any preceding or succeeding aspect, wherein the leachate frequency is determined by 3D image analysis, said method.

[0079] Aspect 21 is the method of any preceding aspect, wherein the method results in a casting speed exceeding 12 m / min, said method.

[0080] Aspect 22 is the method of any preceding aspect, wherein the arcuate nose tip is the nose tip of any preceding aspect, said method.

[0081] All patents, publications, and abstracts cited above are hereby incorporated by reference in their entirety herein. The foregoing description of embodiments, including the illustrated embodiments, is presented only for purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the exact forms disclosed. Many modifications, adaptations, and uses will be apparent to those skilled in the art. The invention disclosed in this specification includes the following aspects: [1] A nozzle tip for continuous casting of a metal alloy, the nozzle tip comprising: a first portion having a first surface parallel to a second surface, the second surface facing the first surface, the first portion; a second portion having a third surface directed towards an extended first surface, the extended first surface being in a common plane with the first surface, the second portion; and a third portion having an arcuate surface connecting the third surface to the extended first surface, the nozzle tip. [2] The nozzle tip according to [1] above, wherein the arcuate surface includes an inflection point. [3] The inflection point is a vertical distance from the extended first surface, the vertical distance being configured to limit the maximum meniscus height of the liquid metal cast using the nozzle tip between the nozzle tip and the continuous casting surface, the nozzle tip according to [2] above. [4] The nozzle tip according to [2] above, wherein the third portion includes a cutback between the inflection point and the extended first surface. [5] The nozzle tip according to [1] above, wherein the third portion includes a turbulence generating mechanism. [6] The turbulence generating mechanism is at least one selected from a plurality of depressions, a plurality of ribs, a plurality of piers, or a surface roughness greater than the surface roughness of the first surface, the second surface, or the extended first surface, the nozzle tip according to [5] above. [7] The nozzle tip according to [1] above, wherein the nozzle tip includes a refractory material. [8] A method for continuous casting of a metal alloy, the method comprising: providing an arcuate nozzle tip, the arcuate nozzle tip comprising: a first portion having a first surface parallel to a second surface, the second surface facing the first surface, the first portion; a second portion having a third surface directed towards an extended first surface, the extended first surface being in a common plane with the first surface, the second portion; and a third portion having an arcuate surface connecting the third surface to the extended first surface, the providing. The method includes flowing liquid metal through the arc-shaped nose tip into a casting cavity to form a casting product. [9] The meniscus length of the liquid metal flowing through the arc-shaped nose tip is at most equal to the distance from the inflection point to the casting surface that partially defines the casting cavity, according to the method described in [8] above.

[10] The meniscus length is 0.5 mm to 2.0 mm, according to the method described in [9] above.

[11] The third portion of the arc-shaped nose tip further includes a turbulent flow generation mechanism, according to the method described in [8] above.

[12] The turbulent flow generation mechanism is at least one selected from surface roughness, a plurality of depressions, a plurality of ribs, a plurality of pores, and combinations thereof, according to the method described in

[11] above.

[13] The method further includes generating turbulent flow in the liquid metal at the arc-shaped surface using magnetic vibration technology, according to the method described in [8] above.

[14] The nose tip is a refractory material, according to the method described in [8] above.

[15] The surface roughness of the casting product is at most 10 μm, according to the method described in [8] above.

[16] The composition near the surface of the casting product has a decrease in Fe and Mn at the casting surface compared to a reference conventional casting standard, according to the method described in [8] above.

[17] The composition is characterized by glow discharge optical emission spectrometry, according to the method described in

[16] above.

[18] The casting product has a maximum leachate frequency of 30 leachates / cm 2 according to the method described in [8] above.

[19] Determining the leachate frequency by 3D image analysis, according to the method described in

[18] above.

[20] The method provides a casting speed exceeding 12 m / min, according to the method described in [8] above.

Claims

1. A nozzle tip for continuous casting of a metal alloy, the nozzle tip comprising: a first portion having a first surface parallel to a second surface, the second surface facing the first surface, the first portion; a second portion having a third surface facing towards an extended first surface, the extended first surface being in a common plane with the first surface, the second portion; a third portion having an arcuate surface connecting the third surface to the extended first surface, wherein the nozzle tip is configured to distribute liquid metal onto a continuous casting surface of a casting cavity in a continuous casting machine, the continuous casting machine is selected from the group consisting of a twin-belt casting machine, a twin-roll casting machine, and a block casting machine, the metal alloy is an aluminum alloy, the nozzle tip has, in order from an inlet to an outlet of the casting cavity, the first portion, the second portion, and the third portion, the second surface and the third surface face the side of the liquid metal, and the first surface and the extended first surface face the continuous casting surface side, and the third portion includes a turbulent flow generating mechanism, the nozzle tip.

2. the arcuate surface includes a bending point, and the bending point is a vertical distance from the extended first surface, the vertical distance being configured to limit a maximum meniscus height of the liquid metal cast using the nozzle tip between the nozzle tip and the continuous casting surface, The nozzle tip according to claim 1.

3. The nozzle tip according to claim 2, wherein the third portion includes a cutback between the bending point and the extended first surface.

4. The turbulent flow generating mechanism is at least one selected from a plurality of depressions, a plurality of ribs, a plurality of piers, or a surface roughness greater than the surface roughness of the first surface, the second surface, or the extended first surface. The nozzle tip according to claim 1.

5. The nozzle tip according to claim 1, wherein the nozzle tip includes a refractory material.

6. A method for continuous casting of a metal alloy, the method comprising: providing an arcuate nozzle tip, the arcuate nozzle tip comprising: A first portion having a first surface parallel to the second surface, wherein the second surface faces the first surface, the first portion, A second portion having a third surface facing the extended first surface, wherein the extended first surface is in the same plane as the first surface, the second portion, A third portion having an arcuate surface connecting the third surface to the extended first surface, including the preparing, Casting a liquid metal through the arcuate nozzle tip into a casting cavity to form a casting, including, Here, The nozzle tip is configured to distribute liquid metal to a continuous casting surface of a casting cavity in a continuous casting machine, The continuous casting machine is selected from the group consisting of a twin-belt casting machine, a twin-roll casting machine, and a block casting machine, The metal alloy is an aluminum alloy, The nozzle tip has the first portion, the second portion, and the third portion in order from the inlet to the outlet of the casting cavity, The second surface and the third surface face the side of the liquid metal, and the first surface and the extended first surface face the continuous casting surface side, and The third portion of the arcuate nozzle tip further includes a turbulent flow generation mechanism, The method.

7. The meniscus length of the liquid metal flowing through the arcuate nozzle tip is at most equal to the distance from the inflection point to the casting surface that partially defines the casting cavity, according to the method of claim 6.

8. The meniscus length is 0.5 mm to 2.0 mm, according to the method of claim 7.

9. The turbulent flow generation mechanism is at least one selected from surface roughness, a plurality of depressions, a plurality of ribs, a plurality of piers, and combinations thereof, according to the method of claim 6.

10. Further including generating turbulent flow in the liquid metal on the arcuate surface using magnetic vibration technology, according to the method of claim 6.

11. The nozzle tip is a refractory material, according to the method of claim 6.

12. The surface roughness of the casting is at most 10 μm, according to the method of claim 6.

13. The metal alloy is an aluminum alloy, and the composition near the surface of the casting has a decrease in Fe and Mn on the casting surface compared to a reference conventional casting standard, according to the method of claim 6.

14. The method according to claim 13, wherein the composition is characterized by glow discharge optical emission spectrometry. **Claim 15** The cast product has a maximum number of surface defects of 30 surface defects / cm ２ and Here, the surface defect is a surface defect formed on or near the surface of the casting, which is caused by reheating a region near the surface of the slab when the solidifying casting slab contracts in a direction away from the cooling surface, the number of the surface defects is determined by 3D image analysis, and the diameter of the surface defect measured by the 3D image analysis is 50 μm or less. The method according to claim 6. **Claim 16** The method according to claim 6, wherein the method provides a casting speed exceeding 12 m / min.

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