KR20230156840A - Nose tip design for high-performance continuous casting - Google Patents

Abstract

Nose tips for continuous casting of metal alloys are described. The nose tip can include a first portion having a first surface parallel to a second surface opposite the first surface. The nose tip may include a second portion having a third surface facing the extended first surface. The expanded 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 elongated first surface. The arcuate surface may include a point of curvature at a vertical distance from the expanded first surface. The vertical distance can be configured to limit the maximum meniscus height for liquid metal, cast using the nose tip, between the nose tip and the continuous casting surface. Methods for continuous casting of metal alloys at casting speeds greater than 12 m/min are also described.

Description

Nose tip design for high-performance continuous casting

Cross-reference to related applications

This application claims the benefit and priority of U.S. Provisional Application No. 63/195,731, filed June 2, 2021, which is incorporated herein by reference in its entirety for all purposes.

Field

The present disclosure relates generally to metallurgy and more specifically to continuous casting of alloy products using continuous casting devices.

Techniques for manufacturing metal strip articles, such as metal strips, slabs or plates, may include using continuous casting equipment. For example, aluminum alloy strip products can be cast using continuous casting. Certain continuous casting devices, such as belt casters, can be used to solidify liquid metal passing between the moving, cooling surfaces of the continuous casting device. These systems generally have limits to the speed at which metal strip can be continuously cast while achieving acceptable surface quality.

The term examples and similar terms are intended to broadly refer to all subject matter of this disclosure and the claims below. Statements containing these terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of the claims below. Embodiments of the disclosure covered herein are defined by the claims below and not by this summary. This summary is a high-level overview of various aspects of the disclosure and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used separately to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all drawings, and each claim of this disclosure as appropriate.

In one aspect, a nose tip for continuous casting of metal alloys is described. A nose tip of this aspect may include a first portion having a first surface parallel to the second surface. The second surface may be opposite the first surface. The nose tip may include a second portion having a third surface facing 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 elongated first surface.

In an example, an arcuate surface may include a point of curvature. The point of curvature may be a perpendicular distance from the extended first surface. The vertical distance can be configured to limit the maximum meniscus height for liquid metal cast using the nose tip between the nose tip and the continuous casting surface.

In an example, the third portion of the nose tip may include a turbulence generating mechanism. The turbulence generating mechanism may be at least one selected from a plurality of dimples, 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.

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 material such as boron nitride (BN).

In another aspect, a method for continuously casting a metal alloy is described. This aspect of the method may include providing an arcuate nose tip. The arcuate nose tip includes a first portion having a first surface parallel to the second surface, the second surface being opposite the first surface; a second portion having a third surface facing the extended first surface, the extended first surface being in a common plane with the first surface; and a third portion having an arcuate surface connecting the third surface to the elongated first surface. The method may include flowing liquid metal through an arcuate nose tip into a casting cavity to form a cast product.

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

In an example, the third portion of the arcuate nose tip may further include a turbulence generating mechanism. The turbulence generating mechanism may be at least one selected from surface roughness, multiple dimples, multiple ribs, multiple piers, and combinations thereof.

In an example, the method may further include generating turbulence in the liquid metal at the arcuate surface using magnetic oscillation techniques.

In an example of the method, the nose tip can include a refractory material.

In an example, the surface roughness of the cast product may be up to 10 μm. Surface roughness can be measured, for example, through 3D image analysis. The casting product may have a near-surface composition with reduced Fe and Mn at the casting surface compared to a conventional reference casting standard. The composition may be characterized by Glow Discharge Optical Emission Spectroscopy. The exudation frequency of cast products can be up to 30 exudates/cm ² . Exudation frequency can be determined, for example, by 3D image analysis.

In embodiments, the disclosed method is useful for casting at speeds faster than 12 m/min.

Other objects and advantages will become apparent from the following detailed description of non-limiting examples.

This specification refers to the following accompanying drawings, wherein the use of like reference numerals in different drawings is intended to illustrate like or similar components.
1 provides a schematic diagram of an exemplary nosetip with a liquid metal meniscus and prow for a continuous casting configuration.
Figure 2 provides a schematic diagram of a belt casting device with a modified nose tip.
Figure 3 provides a detailed schematic diagram of the modified nose tip of Figure 2.
Figure 4a provides a schematic diagram of laminar flow over a smooth object surface.
Figure 4b provides a schematic diagram of turbulent flow for an object with turbulent flow mechanisms such as dimples.
Figure 5 provides a schematic diagram of a modified nose tip incorporating a turbulence generation mechanism.
Figure 6 provides a schematic diagram of a modified nose tip including a cutback.

Nose tips for continuous casting are described herein. Nosetips include an arcuate surface and, optionally, a turbulence mechanism. Also described herein are methods of casting using nose tips, and products formed from aluminum alloys cast using nose tips. The disclosed nosetips are also referred to interchangeably herein as arcuate nosetips. The disclosed nosetips include an arcuate surface with a point of curvature that defines the maximum height, or distance from the belt, over which the meniscus can extend. The disclosed nosetips are better than nosetips, such as nosetip 100 shown in FIG. 1 in a partial cross-sectional schematic including a prow with a cutback. The disclosed arcuate nose tips reduce meniscus height, thereby increasing the stability of liquid aluminum flow. By increasing flow stability, surface defects in cast products are reduced and higher casting speeds can be achieved. The amplitude of meniscus oscillations that occur during casting can be reduced to provide improved heat removal. Better consistency of heat removal results in fewer surface defects. Increased casting speeds are achieved by limiting surface defects without developing unstable meniscus vibration regimes.

As shown in FIG. 1 , an exemplary nose tip 100 for a continuous caster includes a prow 120 . Liquid metal 152 separates from nose tip 100 at the prow, where a gas/liquid interface meniscus 150 is formed. The prow 120 includes a cutback, angled with respect to the vertical line L, perpendicular to the belt B, in order to ensure that the meniscus oscillates at regular intervals and does not intermittently adhere to the face of the nose tip 100, which Nose tip material/oxide reactions and uneven surface appearance may result. The cutback provides a single point of contact, and the meniscus height extends to the prow tip. A liquid metal meniscus 150 is formed during casting and extends to height H of the prow. Direction D represents the direction in which the decomposed release agent passes between the nose tip 100 and belt B and exits.

Conventional continuous casting devices can have difficulty creating the desired surface of cast metal products. Surface defects may result in waste (eg, in cases where the cast metal product cannot be used) or the need for further downstream processing (eg, to correct or alleviate any correctable surface defects). The conventional configuration also results in casting speed limitations. For example, conventional casting speeds are limited to a maximum of 12 m/min. A casting speed of 12 m/min refers to the casting product coming out of the casting device at a speed of 12 meters of casting product per minute in the casting direction. Nosetips of the present disclosure can increase stability during casting by reducing meniscus height to provide metal articles with fewer defects, more uniform heat removal, higher casting speeds, and higher production throughput. .

Definition and Description

As used herein, the terms “invention”, “the invention”, “this invention” and “the present invention” refer to the present patent application and the following. It is intended to refer broadly to all subject matter of the claims. Statements containing these terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of the patent claims below.

As used herein, the terms “top” and “bottom” may relate to vertical positions when the continuous casting device is cast in a horizontal direction. However, in some cases, the continuous casting device may be used in a non-horizontal orientation, in which case the terms “top” and “bottom” may refer to positions in a plane perpendicular to the casting direction of the continuous casting device.

A continuous caster or continuous casting device may include a pair of opposing cooling assemblies forming a casting cavity therebetween. In some cases, additional features, such as side dams, may further define the extent of the casting cavity. Each cooling assembly includes at least one cooling surface for extracting heat from the liquid metal in the casting cavity, as well as additional equipment for operation of the cooling surface or cooling assembly (e.g., cooling pads, motors, coolant piping). piping, sensors, and other such equipment).

Some continuous casters, such as belt casters, may include two counter-rotating belts (e.g., opposing cooling surfaces) that, together with side dams, form a casting cavity into which liquid metal can be supplied. . Belts may be water cooled (e.g., cooled with deionized water) or cooled using other fluids. Liquid metal entering the casting cavity at the casting cavity inlet may solidify, through heat extraction through cooled belts, and as it moves distally towards the exit of the casting cavity, the solidified metal (e.g., a continuously cast article) ) to exit. The metal can move through the casting device at approximately the same speed of movement of the belts, thereby minimizing or eliminating shear forces between the belts and the solidifying metal. Cooling pads can be used to control casting. Cooling pads may include multiple nozzles positioned along the surface of the cooling pad and arranged in a pattern, such as a hexagon or other pattern. In some cases, the cooling pad may include at least one linear nozzle extending across the width of the cooling pad and/or substantially or entirely across the width of the casting cavity.

In this description, reference is made to alloys identified by AA numbers and other related designations, such as “series” or “7xxx”. For an understanding of the numbering designation system most commonly used to name and identify aluminum and its alloys, see “International Alloy Nomenclature for Wrought Aluminum and Wrought Aluminum Alloys” published by the Aluminum Association. See “Chemical Composition Restrictions” or “Registration Record of Aluminum Association Alloy Names and Chemical Composition Restrictions for Aluminum Alloys in Castings and Ingot Form”.

As used herein, a plate generally has a thickness greater than about 15 mm. For example, plate refers to an aluminum product having a thickness of 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. can do.

As used herein, sheet metal (also referred to as sheet plate) generally has a thickness of about 4 mm to about 15 mm. For example, the sheet metal 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.

As used herein, sheet generally refers to aluminum products having a thickness of less than about 4 mm. For example, the sheet may have a thickness of 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., less than about 0.2 mm).

As used herein, terms such as “cast aluminum alloy product”, “cast product”, “cast aluminum alloy product”, “cast article”, etc. are interchangeable and refer to direct cooled casting (direct cooled cavity). -including casting) or semi-continuous casting, continuous casting, electromagnetic casting, hot top casting, or any other casting method, but herein specifically refers to continuous casting. Refers to products produced by casting (including, for example, the use of twin belt casters, twin roll casters, block casters or any other continuous casters). The cast articles described herein may be processed by any means known to those skilled in the art. These processing steps include, but are not limited to, homogenization, hot rolling, cooling rolling, solution heat treatment, and optional pre-aging steps.

Aluminum alloy products, including strips, slabs, sheets, sheet metals or plates, manufactured using continuous casters using arcuate nosetips described herein, include aircraft and railway applications, automotive applications. and other transportation applications. For example, the disclosed aluminum alloy products include bumpers, side beams, roof beams, cross beams, pillar reinforcement (e.g., A-pillars, B-pillars, and C-pillars), interior It can be used to manufacture automotive structural parts and formed parts, such as panels, exterior panels, side panels, interior hoods, exterior hoods or trunk lid panels. The aluminum alloy products and methods described herein may also be used in aircraft or rail vehicle applications, for example, to manufacture exterior and interior panels.

Aluminum alloy products and methods described herein can also be used in electronic applications. For example, the aluminum alloy products and methods described herein can be used to prepare housings for electronic devices, including cell phones and tablet computers. In some examples, aluminum alloy products can be used to manufacture housings for outer cases of cell phones (e.g., smartphones), tablet lower chassis, and other portable electronic devices.

The aluminum alloy products and methods described herein may be used in any other desired application.

All ranges disclosed herein are to be understood to include any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; That is, all subranges begin with a minimum value greater than or equal to 1, such as 1 to 6.1, and end with a maximum value less than or equal to 10, such as 5.5 to 10. Unless otherwise specified, the expression "up to" when referring to a composition of an element is optional and means including 0% composition of that particular element. Unless otherwise specified, all composition percentages are in weight percent (wt.%).

As used herein, the singular terms “a”, “an” and “the” include singular and plural references, unless the context clearly dictates otherwise.

Nose tips for continuous casting

These illustrative examples are provided to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the concepts disclosed. The following sections describe various additional features and examples with reference to the drawings where like numbers represent like elements, and directional descriptions are used to describe example embodiments, but, like the example embodiments, do not limit the disclosure. It should not be used to Elements included in the examples herein may not be drawn to scale. In particular, the angles of attack illustrated herein are exaggerated for illustrative purposes.

Nosetips for continuous casting, such as an arched nosetip, are described herein. 2 is a cross-sectional or side schematic diagram depicting a continuous casting device 200 in accordance with certain aspects of the present disclosure. The continuous casting device 200 includes an upper belt assembly 202 and a lower belt assembly 204, between which a casting cavity 250 is located. Each of the upper belt assembly 202 and lower belt assembly 204 may include a cooling belt 208, a proximal support 210, and a distal support 212. In some cases, proximal support 210 may be a proximal cooling pad, used to extract heat from cooling belt 208. In some cases, distal support 212 may be a distal cooling pad, used to extract heat from cooling belt 208. In cases where the proximal support 210 and/or distal support 212 are not cooling pads, heat extraction from the cooling belt 208 may be accomplished using other cooling elements, such as coolant nozzles, spray bars or any other suitable cooling element. This can be achieved using the elements: As used herein, with reference to cooling pads, supports, etc., the term "proximal" means located at or near the entrance to the casting cavity 250, such as where liquid metal enters the casting cavity 250. It can refer to structures. As used herein, with reference to cooling pads, supports, etc., the term “distal” refers to a location at or near the exit of the casting cavity 250, such as where the solidified metal exits the casting cavity 250. It can refer to structures that are

2 depicts a single proximal support 210 and a single distal support 212 for each of the upper belt assembly 202 and lower belt assembly 204, however, other numbers of supports or cooling pads may be used. . In some cases, proximal support 210 and/or distal support 212 may each include a plurality of supports and/or cooling pads to achieve a two-stage convergence profile. It can be configured to do so. In some cases, additional supports (e.g., additional cooling pads) may be used in the proximal support 210 and distal support 212 to provide additional stages to the convergence profile, such as achieving a three or more stage convergence profile. ) is placed between

Belt 208 may be made of any suitable heat-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 and the belts 208 come into contact with the liquid metal 252 within the casting cavity 250. ) so that the surfaces move in the downstream direction (254). The upper belt assembly 202 and lower belt assembly 204 may further include additional equipment, such as motors and other equipment, as needed.

Liquid metal 252 may enter casting cavity 250 through nozzle 214. Within casting cavity 250, liquid metal 252 may solidify as heat is extracted through belts 208 of upper belt assembly 202 and lower belt assembly 204. Liquid metal 252 and solidifying liquid metal move within casting cavity 250 in direction 254 . After sufficient heat has been extracted, liquid metal 252 becomes solid and can subsequently exit casting cavity 250 as cast article 206. The continuous casting article 206 will exit the continuous casting device 200 at the exit temperature. Nozzles 214 may be at least one linear nozzle extending across the width of the cooling pad and/or substantially or entirely across the width of casting cavity 250 . Nozzle 214 may include a nose tip, such as an arcuate nose tip, as described herein.

Casting cavity 250 has an inlet (e.g., at nozzle 214), an outlet (e.g., where continuous casting article 206 exits casting cavity 250), side dams, and an upper belt assembly ( 202) and lower belt assembly 204. More specifically, as the belts 208 of the upper and lower belt assemblies 202 and 204 move, the upper and lower portions of the casting cavity 250 are positioned at the entrance and exit of the casting cavity 250 at any given point in time. It is bounded by the outer surfaces 256 of the intervening belts 208. The path of these outer surfaces 256 can be adjusted by pushing them from within the upper and lower belt assemblies 202, 204 (e.g., from opposite the belts 208 from the casting cavity 250). there is. As depicted in Figure 2, proximal support 210 and distal support 212 are located within each of the upper and lower belt assemblies 202 and 204. Proximal support 210 and distal support 212 may be in physical contact with belt 208 to define the path of belt 208 and the path of the outer surface 256 of belt 208. The path of the outer surfaces 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.

FIG. 3 depicts a partial cross-sectional view of an example arcuate nose tip 300 for dispensing liquid metal 352 into a casting cavity, e.g., from nozzle 214 of FIG. 2 into cavity 250. Liquid metal 352 may exit nose tip 300 and begin to fill the casting cavity, contacting the outer surface 308 of belt B. Meniscus atmosphere 354 fills the space below nose tip 300 and above belt B. A meniscus 350 forms in the liquid metal 352 between the nose tip 300 and the outer surface 308 of the belt B. As the liquid metal 352 cools, it begins to solidify until it becomes a solid, continuously cast article (e.g., a metal strip). The solidification distance (not shown) is such that the liquid metal 352 first contacts the belt B and the liquid metal 352 is either completely solidified or sufficiently solidified to cause little or no subsequent solidification shrinkage. It exists between the points

The nose tip 300 may have a first portion 322 having a first surface 321 that is parallel or substantially parallel to the second surface 323 . The second surface 323 is opposite the first surface 321 . Nose tip 300 has a second portion 326 with a third surface 327 facing an extended first surface 325, wherein the extended first surface 325 is common with the first surface 321. It's on a flat surface. As shown in FIG. 3 , third surface 327 is angled in a direction toward elongated first surface 325 . Third surface 327 may be angled, beveled, curved, curved, tapered, or otherwise extended, without third surface 327 in contact with extended first surface 325. can be directed towards Nose tip 300 has a third portion 330 with an arcuate surface 329 connecting third surface 327 to elongated first surface 325 .

The arcuate surface 329 includes a point of curvature p. Liquid metal 352 will move towards belt B at this point of curvature p. Line L extends from point p to the belt outer surface 308. The point of curvature p is a distance h from belt B along line L. The distance h consists of the maximum height of the meniscus 350 and is the height of the liquid metal in contact with the nose tip 300 and belt B.

In some examples, the arcuate nosetips of the present disclosure include a turbulence generating mechanism. Turbulence generating mechanisms are generally defined as any mechanism that provides turbulent flow around a curved body. Figure 4a depicts a schematic diagram of a ball-shaped body with a smooth surface, while Figure 4b depicts a schematic diagram of a ball-shaped body with a hollow surface. In the case of a hollow surface body, due to the presence of turbulent vortices, the turbulent boundary layers may remain attached at a much steeper angle than similar laminar boundary layers. This effect causes the flow around the ball body in Figure 4b to become turbulent. As a result, the flow remains attached past the top central point of the ball body and separates only on the opposite side of the ball body. As a result, there is less pressure drag for the ball body in Figure 4b than for the comparative ball body with a smooth surface as in Figure 4a.

This concept of the effect of turbulent vortices on ball bodies applies to the arcuate nosetips of the present disclosure. In some examples, the arcuate nosetip has a third portion that includes a turbulence generating mechanism. 5 depicts a modified nose tip 500 including a turbulence generating mechanism 520. This increased turbulence causes the flow to adhere longer to the nose tip exit (e.g. at the point of curvature p), which reduces the overall height of the meniscus formed. This reduced meniscus height results in improved surface finish due to the reduced amplitude of meniscus vibrations. In addition to reducing the spacing of meniscus marks on the casting surface, this results in a reduction of thermal gradients within adjacent layers of the newly solidified casting surface. Surface defects, such as exudates or blebs, often form along meniscus marks, due to small differences in the solidification rates of adjacent areas. By reducing the distance between meniscus marks, differences in solidification rates will be reduced in adjacent areas and fewer defects would be expected to form. An increase in casting speed is also achieved because the meniscus remains stable through a larger range of casting speeds. Conventional continuous casting devices were limited in casting speed due to surface defects due to meniscus vibrations.

In some examples, turbulence generating mechanism 520 may include at least one selected from surface roughness, a plurality of dimples, a plurality of ribs, a plurality of piers or similar structures, and combinations thereof. Including, but not limited to one. Additionally or alternatively, in some examples, the turbulence generating mechanism includes magnetic oscillation and a controllable electromagnet is used to interact with the liquid metal at the location of the turbulence generating mechanism 520 depicted in FIG. 5 . By combining an arcuate nose tip with a turbulence generation mechanism, the liquid metal flow remains attached to the nose tip up to a much steeper angle, reducing meniscus length and increasing stability at faster casting speeds.

5 depicts a partial cross-sectional view of an arcuate nose tip 500 for dispensing liquid metal 552 into a casting cavity, wherein the nose tip 500 includes an arcuate surface 529 and a surface of the nose tip 500. The same additionally includes a turbulence generating mechanism (520). A meniscus 550 forms in the liquid metal 552 between the nose tip 500 of the nozzle and the outer surface 508 of the belt B. Meniscus atmosphere 554 fills the space below nose tip 500 and above belt B. As liquid metal 552 cools, it begins to solidify until it becomes a solid, continuous cast article (e.g., a metal strip). Nose tip 500 includes a first portion 522 having a first surface 521 parallel to second surface 523, where second surface 523 is opposite first surface 521. there is. Nose tip 500 has a second portion 526 with a third surface 527 facing toward an extended first surface 525 , where the extended first surface 525 is common to the first surface 521 . It's on a flat surface. As shown in FIG. 5 , third surface 527 is angled in a direction toward elongated first surface 525 . Third surface 527 may be inclined, sloped, curved, curved, tapered, or otherwise inclined toward elongated first surface 525 , without third surface 527 in contact with elongated first surface 525 . It can be oriented differently. Nose tip 500 has a third portion 530 with an arcuate surface 529 connecting third surface 527 to elongated first surface 525 . The arcuate surface 529 includes a point of curvature p. The point of curvature p is a distance h from belt B along line L. The distance h consists of the maximum height of the meniscus 550 and is the height of the liquid metal in contact with the nose tip 500 and the belt. Depending on the type of turbulence generating mechanism 520, meniscus 550 may change their shape or length compared to the shape or length of meniscus 350 depicted in FIG. 3. In one example, turbulence generating mechanism 520 includes a plurality of dimples, although other turbulence generating mechanisms are contemplated and may be included, at least in part, in an arcuate surface. Examples of turbulence generating mechanisms 520 include, but are not limited to, surface roughness, multiple ribs, multiple piers, and other such structures, and combinations thereof.

6 depicts a partial cross-sectional view of another nose tip 600 for dispensing liquid metal 652 into a casting cavity, where the nose tip 600 includes an arcuate surface 629 and a cutback 631. A meniscus 650 forms in the liquid metal 652 between the nose tip 600 of the nozzle and the outer surface 608 of belt B. As liquid metal 652 cools, it begins to solidify until it becomes a solid, continuous cast article (e.g., a metal strip). Nose tip 600 includes a first portion 622 having a first surface 621 parallel to second surface 623, where second surface 623 is opposite first surface 621. there is. Nose tip 600 has a second portion 626 with a third surface 627 facing an extended first surface 625, where the extended first surface 625 is common with the first surface 621. It's on a flat surface. As shown in FIG. 6 , third surface 627 is angled in a direction toward elongated first surface 625 . The third surface 627 is angled, inclined, curved, curved, or curved toward the extended first surface 625, without the third surface 627 in contact with the extended first surface 625. It may be tapered or otherwise oriented. Nose tip 600 has a third portion 630 with an arcuate surface 629 connecting third surface 627 to cutback 631 . As illustrated, an angle of approximately 15 degrees relative to line L perpendicular to belt B defines cutback 631. Cutback 631 extends to an extended first surface 625 , which extends into portion 630 . The arcuate surface 629 includes a point of curvature p coincident with one end of the cutback 631 and the other end of the cutback 631 where it meets the extended first surface 625 . The point of curvature p is a distance h from belt B along line L. The distance h consists of the maximum height of the meniscus 650 and is the height of the liquid metal in contact with the nose tip 600 and the belt.

Optionally, portion 630 may include a turbulence generating mechanism 620 as described above. The meniscus 650 may change its shape or length compared to the meniscus 350 depicted in FIG. 3 or the meniscus 550 depicted in FIG. 5 . In one example, optional turbulence generating mechanism 620 includes a plurality of dimples, although other turbulence generating mechanisms are contemplated and may be included, at least in part, in an arcuate surface. Examples of turbulence generating mechanisms 620 include, but are not limited to, surface roughness, multiple ribs, multiple piers, and other such structures, and combinations thereof.

Nose tips of the present disclosure, such as nose tip 300 of FIG. 3, nose tip 500 of FIG. 5, and nose tip 600 of FIG. 6, may be any refractory material capable of withstanding the temperature of the liquid metal being cast. ) can be manufactured from materials. In some instances, the refractory material has high surface energy for excellent non-wetting properties. The arcuate shape of the nose tip and/or the turbulence generating mechanism may be manufactured using known techniques. The refractory material should not be so thin or brittle that it can be easily damaged, for example by cracking or denting, which could affect the casting surface. In other examples, nose tips, such as nose tip 300 of FIG. 3, nose tip 500 of FIG. 5, and nose tip 600 of FIG. 6, are made of a refractory or non-refractory material and then highly polished for excellent non-wetting properties. It can be coated with a material having surface energy. Boron nitride (BN) may be used as a coating on the nose tip in a non-limiting example.

Disclosed aluminum alloys and methods of manufacturing aluminum alloy products

The aluminum alloys and aluminum alloy products described herein, individually, are known to those skilled in the art using nosetips described herein, such as the arcuate nosetips 300, 500, and 600 of FIGS. 3, 5, and 6. It may be continuously cast using any suitable continuous casting method. In some examples, the nose tip has a first surface parallel to the second surface, the second surface comprising a first portion opposite the first surface; a second portion having a third surface facing the extended second surface, the extended second surface being in a common plane with the second surface; and a third portion having a curved surface connecting the third surface and the extended second surface and including a point of curvature. The method further includes casting the liquid metal utilizing an arcuate nose tip configured to provide a meniscus length that is at most equal to the distance from the point of curvature to the belt. In some examples, the meniscus length ranges from about 0.5 mm to about 2 mm, such as from 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. has

Continuous casting of the aluminum alloys described herein can provide a cast product with a surface roughness, or Ra value, that is less than the surface roughness of a cast product using a conventional nose tip. Surface roughness can alternatively be measured by defect count, including defect size and distribution, for example through image analysis. Since the defect count is measured in an area where the Ra value is relatively small, it can provide a better representation of the surface roughness of the cast product due to the larger sampling area. Therefore, if defects are not evenly distributed on the surface, there may be greater variation in Ra from measurement location to measurement location. In some examples, cast products of the present disclosure have surfaces that exhibit few surface defects and provide Ra values 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.

The methods described herein can result in fewer surface defects at or near the surface of the cast product. Defects may include exudates. Exudates are surface defects that result from reheating of nearby surface areas of a casting slab, which solidifies as the slab shrinks on the cooled surface. The density of exudates may vary depending on the alloy, and 6xxx alloys are prone to exudates. The exudates may be less than about 50 μm in diameter depending on the alloy. In some examples, cast aluminum alloys have an exudation frequency of up to 30 exudates/cm ² as measured by image analysis. Exudate heights range from about 5 μm to about 100 μm. Roughness can be measured by measuring the height of the defect (exudate) through 3D imaging (Keyence).

The methods described herein can provide casting speeds greater than 12 m/min, greater than 14 m/min, greater than 16 m/min, or greater than 18 m/min. Casting speed can be improved by up to 50% or more compared to casting speed using a conventional nose tip, which is limited to 12 m/min.

Casting products according to the present disclosure can provide near-surface compositions with fewer defects and impurities. Near-surface compositions can be analyzed with glow discharge optical emission spectroscopy (GDOES) to obtain measurements of elemental concentrations as a function of depth. The near-surface composition can be characterized with GDOES for elemental analysis to a desired depth, for example up to 1 μm, up to 2 μm, up to 5 μm, up to 10 μm, up to 15 μm or larger or smaller depths. Conventional continuous casting products may contain the presence of Fe and Mn on the continuously cast final gauge product surface with a denuded zone below the surface, in contrast to standard direct casting processed products. This is likely due to the presence of Fe and/or Mn containing surface intermetallics resulting from continuous casting. The casting product has a composition near the expression with a reduction in Fe and Mn compared to the reference conventional casting standard.

In some instances, the number of surface defects including exudates in the near-surface composition is low, reducing the Fe and Mn contents of the casting surface.

Exemplary Aspects

As used below, any reference to a series of aspects (e.g., “aspects 1 through 4”) or a group of unlisted aspects (e.g., “a preceding or subsequent aspect”) Separate reference to each of these aspects should be understood (e.g., “aspects 1 to 4” should be read as “aspects 1, 2, 3 or 4”).

Aspect 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, wherein the second surface is opposite the first surface; a second portion having a third surface facing the extended first surface, wherein the extended first surface is in a common plane with the first surface; and a third portion having an arcuate surface connecting the third surface to the elongated first surface.

Aspect 2 is the nosetip of any preceding or succeeding aspect, wherein the arcuate surface includes a point of curvature.

Aspect 3 is the nose tip of any preceding or subsequent aspect, wherein the point of curvature is a vertical distance from the elongated first surface, the vertical distance being between the nose tip and a continuous casting surface, wherein the nose tip is used to cast using the nose tip. is configured to limit the maximum meniscus height of the liquid metal.

Aspect 4 is the nosetip of any preceding or subsequent aspect, wherein the third portion includes a cutback between the point of curvature and the elongated first surface.

Aspect 5 is the nose tip of any previous or subsequent aspect, wherein the third portion includes a turbulence generating mechanism.

Aspect 6 is the nosetip of any previous or subsequent aspect, wherein the turbulence generating mechanism includes a plurality of dimples, a plurality of ribs, a plurality of piers, or a plurality of dimples, a plurality of ribs, a plurality of piers, or At least one is selected from the surface roughness greater than the surface roughness of the 1 surface.

Aspect 7 is the nosetip of any preceding or subsequent aspect, wherein the nosetip includes a refractory material.

Aspect 8 is a method of continuously casting a metal alloy, the method comprising: providing an arcuate nose tip, wherein the arcuate nose tip comprises: a first portion having a first surface parallel to the second surface; the second surface is opposite the first surface; a second portion having a third surface facing the extended first surface, wherein the extended first surface is in a common plane with the first surface; and a third portion having an arcuate surface connecting the third surface to the extended first surface; and flowing liquid metal through the arcuate nose tip into the casting cavity to form a casting product.

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

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

Aspect 11 is the method of any preceding or subsequent aspect, wherein the third portion of the arcuate nose tip further comprises a turbulence generating mechanism.

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

Aspect 13 is the method of any preceding or subsequent aspect, further comprising generating turbulence in the liquid metal at the arcuate surface using a magnetic oscillation technique.

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

Embodiment 15 is the method of any preceding or subsequent aspect, wherein the cast product has a surface roughness of up to 10 μm.

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

Aspect 17 is the method of any preceding or subsequent aspect, wherein the casting product has a near-surface composition having a reduction in Fe and Mn at the casting surface compared to a baseline conventional casting standard.

Embodiment 18 is the method of any preceding or subsequent aspect, wherein the composition is characterized by glow discharge optical emission spectroscopy.

Aspect 19 is the method of any preceding or subsequent aspect, wherein the cast product has an exudate frequency of up to 30 exudates/cm ² .

Aspect 20 is the method of any preceding or subsequent aspect, wherein the exudate frequency is determined by 3D image analysis.

Aspect 21 is the method of any preceding or subsequent aspect, wherein the method provides a casting speed greater than 12 m/min.

Aspect 22 is the method of any of the preceding aspects, wherein the arcuate nose tip is the nose tip of any of the preceding aspects.

All patents, publications and abstracts cited above are hereby incorporated by reference in their entirety. The foregoing description of embodiments, including illustrative embodiments, has been presented for purposes of illustration and description only and is not intended to be exhaustive or to limit the precise form disclosed. Various modifications, applications and uses thereof will be apparent to those skilled in the art.

Claims (20)

A nose tip for continuous casting of a metal alloy, the nose tip having:
a first portion having a first surface parallel to the second surface, wherein the second surface is opposite the first surface;
a second portion having a third surface facing the extended first surface, wherein the extended first surface is in a common plane with the first surface; and
A nose tip comprising a third portion having an arcuate surface connecting the third surface to the elongated first surface. 2. The nose tip of claim 1, wherein the arcuate surface includes a point of curvature. 3. The method of claim 2, wherein the point of curvature is a vertical distance from the elongated first surface, the vertical distance being the maximum meniscus of the liquid metal cast using the nose tip between the nose tip and a continuous casting surface. A nose tip configured to limit meniscus height. 3. The nose tip of claim 2, wherein the third portion includes a cutback between the point of curvature and the elongated first surface. 2. The nose tip of claim 1, wherein the third portion includes a turbulence generating mechanism. 6. The method of claim 5, wherein the turbulence generating mechanism comprises a plurality of dimples, a plurality of ribs, a plurality of piers, or a plurality of piers on the first surface, the second surface, or the extended A nose tip, wherein at least one is selected from a surface roughness greater than that of the first surface. 2. The nose tip of claim 1, wherein the nose tip comprises a refractory material. A method of continuously casting a metal alloy, said method comprising:
Providing an arched nose tip, wherein the arched nose tip:
a first portion having a first surface parallel to the second surface, wherein the second surface is opposite the first surface;
a second portion having a third surface facing the extended first surface, wherein the extended first surface is in a common plane with the first surface; and
comprising a third portion having an arcuate surface connecting the third surface to the elongated first surface; and
flowing liquid metal through the arcuate nose tip into a casting cavity to form a cast product. 9. The method of claim 8, wherein the meniscus length of the liquid metal flowing through the arcuate nose tip is at most equal to the distance from the point of curvature to the casting surface partially defining the casting cavity. 10. The method of claim 9, wherein the meniscus length is 0.5 mm to 2.0 mm. 9. The method of claim 8, wherein the third portion of the arcuate nose tip further comprises a turbulence generating mechanism. 12. The method of claim 11, wherein the turbulence generating mechanism is at least one selected from surface roughness, a plurality of dimples, a plurality of ribs, a plurality of piers, and combinations thereof. 9. The method of claim 8, further comprising generating turbulence in the liquid metal at the arcuate surface using a magnetic oscillation technique. 9. The method of claim 8, wherein the nose tip is a refractory material. 9. The method of claim 8, wherein the cast product has a surface roughness of at most 10 μm. 9. The method of claim 8, wherein the casting product has a near-surface composition with a reduction in Fe and Mn at the casting surface compared to a baseline conventional casting standard. 17. The method of claim 16, wherein the composition is characterized by Glow Discharge Optical Emission Spectroscopy. 9. The method of claim 8, wherein the casting product has an exudation frequency of up to 30 exudates/cm ² . 19. The method of claim 18, wherein the exudate frequency is determined by 3D image analysis. 9. The method of claim 8, wherein the method provides a casting speed greater than 12 m/min.