Patent Description:
Certain continuous casting devices, such as belt casters, can be used to solidify molten metal as it passes between moving, cooling surfaces of the continuous casting device. In some cases, the cooling surfaces can be the surfaces of moving belts of a continuous belt caster.

Molten metal can be injected into the space between the belts and come into contact with the cooling surfaces. The cooling surfaces can extract heat from the molten metal to cause it to solidify. The cooling surfaces can be cooled from the sides opposite the molten metal by a cooling pad.

As the molten metal begins to solidify in the continuous casting device, the metal can shrink as it cools. For example, the metal may shrink in volume by approximately <NUM>% as it cools. As the metal shrinks, it may pull away from the cooling surfaces. In some cases, metal pulling away from the cooling surfaces can result in a decrease in heat transfer between the metal and the cooling surfaces, which can permit the solidifying metal to reheat due to the latent heat within the metal. This reheating may result in surface defects, such as areas of surface exudation, which may be known as blebs. Surface defects can pose mechanical and/or metallurgical problems during the casting or subsequent metal processing steps. For example, in certain alloys, such as aluminum alloys, the eutectic compositions of the alloy may be the first portions to reheat, resulting in a localized region having a different chemical composition than the remainder of the cast metal article. Continuous casting devices can have difficulty in producing a desirable surface of the cast metal article. Surface defects can result in waste (e.g., in cases where the cast metal article cannot be used) or the need for additional downstream processing (e.g., to correct or mitigate any correctable surface defects). Prior art document <CIT> discloses a continuous twin-belt casting system, wherein the casting cavity comprises a proximal zone and a distal zone. In the proximal zone, the belts are shaped by a pair of opposing concave shaping rollers in order to form a bath for the molten metal, the positions of the shaping rollers being fixedly defined on the frame of the system. In the distal zone, the belts are planar and parallel. At both ends of the distal zone, there are cylindrical determining rollers that can be adjusted together in the height direction of the casting cavity in order to determine the thickness of the metal strip to be formed in the system whilst at the same time changing the angle of attack in the proximal zone. <CIT> discloses a twin-belt casting machine having proximal cooling pads that are fixed to the frame of the machine whereas distal cooling pads are pivotable as a unit around an axis in order to create a downstream region of the casting cavity in which the belt loses contact with the slab and thus does not extract heat therefrom in order to influence the exit temperature of the metal strip cast in the machine. <CIT> discloses an apparatus for strip casting of metals on at least one endless belt. The apparatus comprises a casting cavity having an upstream region, which is larger at the point of molten metal entry and tapers to a smaller thickness where a pair of pinch rolls apply a compressive force that sets the final thickness of the cast strip. In the apparatus of <CIT>, the distance between the pinch rolls and their longitudinal position along the belt is adjustable. <CIT> describes a twin-belt casting machine including non-rotating and stationary fluid pillow structures at the entrance end of the machine and exit pulley drums at the exit end. The axes of rotation of the exit pulley drums can be slightly tilted in order to steer the belts.

According to the invention, a metal casting apparatus with the features of claim <NUM>, a metal casting system with the features of claim <NUM> and a method of continuous casting with the features of claim <NUM> are provided. Specific embodiments of the invention are described in the dependent claims. The following 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. The subject matter should be understood by reference to appropriate portions of the entire specification of this disclosure, any or all drawings and each claim.

Examples of the present disclosure include a metal casting system comprising: an opposing pair of cooling assemblies defining a casting cavity therebetween, the casting cavity extending longitudinally between a proximal end and a distal end; and a nozzle positioned at the proximal end of the casting cavity for feeding molten metal into the casting cavity, wherein the opposing pair of cooling assemblies each comprise a cooling surface made of a thermally conductive material for extracting heat from the molten metal within the casting cavity to solidify the molten metal as the molten metal travels towards the distal end of the casting cavity; wherein each of the opposing pair of cooling assemblies includes: at least one proximal cooling pad positioned opposite the cooling surface from the casting cavity for displacing the cooling surface, wherein the at least one proximal cooling pad is longitudinally positioned adjacent to the proximal end of the casting cavity, and wherein the at least one proximal cooling pad is movable to adjust a convergence profile of the casting cavity in a proximal zone of the casting cavity; and at least one distal cooling pad positioned opposite the cooling surface from the casting cavity for displacing the cooling surface, wherein the at least one distal cooling pad is longitudinally positioned between the at least one proximal cooling pad and the distal end of the casting cavity.

In some cases, at least one distal cooling pad is movable to adjust a convergence profile of the casting cavity in a distal zone of the casting cavity between the proximal zone and a distal end of the casting cavity. In some cases, the at least one proximal cooling pad is pivotable to adjust the convergence profile of the casting cavity. According to the invention, the at least one proximal cooling pad includes a plurality of proximal cooling pads, wherein each of the plurality of proximal cooling pads is individually adjustable to adjust the convergence profile of the casting cavity. In some cases, the at least one proximal cooling pad is coupled to at least one actuator for adjusting the convergence profile of the casting cavity during a casting process. In some cases, the at least one proximal cooling pad includes a plurality of linear nozzles extending laterally across a width of the cooling surface. In some cases, each of the cooling surfaces is a continuous metal belt. In some cases, the at least one distal cooling pad is longitudinally spaced apart from the proximal end of the casting cavity by at least a distance at which the molten metal has solidified.

Further examples of the present disclosure include a continuous casting apparatus comprising: an opposing pair of cooling assemblies defining a casting cavity therebetween, the casting cavity extending longitudinally between a proximal end for accepting molten metal and a distal end for outputting solidified metal, wherein each of the cooling assemblies comprises a cooling surface made of a thermally conductive material for extracting heat from the molten metal to form the solidified metal, and wherein each of the cooling assemblies comprises: at least one proximal support positioned opposite the cooling surface from the casting cavity for displacing the cooling surface, wherein the at least one proximal support is longitudinally positioned adjacent to the proximal end of the casting cavity, and wherein the at least one proximal support is movable to adjust a convergence profile of the casting cavity in a proximal zone of the casting cavity; and at least one distal support positioned opposite the cooling surface from the casting cavity for displacing the cooling surface, wherein the at least one distal support is longitudinally positioned between the at least one proximal support and the distal end of the casting cavity.

In some cases, the at least one distal support is movable to adjust a convergence profile of the casting cavity in a distal zone of the casting cavity between the proximal zone and a distal end of the casting cavity. In some cases, the at least one proximal support is pivotable to adjust the convergence profile of the casting cavity. According to the invention, the at least one proximal support includes a plurality of proximal supports, wherein each of the plurality of proximal supports is individually adjustable to adjust the convergence profile of the casting cavity. In some cases, the at least one proximal support is coupled to at least one actuator for adjusting the convergence profile of the casting cavity during a casting process. In some cases, at least one of the at least one proximal support and the at least one distal support includes a cooling pad for extracting heat from the cooling surface. In some cases, each of the cooling surfaces is a continuous metal belt.

Further examples of the present disclosure include a method of continuous casting comprising: providing molten metal to a casting cavity between an opposing pair of cooling assemblies at a proximal end of the casting cavity; extracting heat from the molten metal to solidify the molten metal into a solidified metal exiting at a distal end of the casting cavity; adjusting a convergence profile of the casting cavity at a proximal region, wherein the proximal region is adjacent the proximal end of the casting cavity; and adjusting the convergence profile of the casting cavity at a distal region, wherein the distal region is located between the proximal region and a distal end of the casting cavity.

In some cases, adjusting the convergence profile of the casting cavity at the proximal region includes adjusting, for each of the opposing pair of cooling assemblies a proximal angle of attack of a cooling surface of the cooling assembly, wherein the proximal angle of attack defines an orientation of the cooling surface with respect to a centerline of the casting cavity at the proximal region; and adjusting the convergence profile of the casting cavity at the distal region includes adjusting, for each of the opposing pair of cooling assemblies, a distal angle of attack of the cooling surface of the cooling assembly, wherein the distal angle of attack defines an orientation of the cooling surface with respect to a centerline of the casting cavity at the distal region. Adjusting the convergence profile of the casting cavity at the proximal region includes, for each of the opposing pair of cooling assemblies, individually moving theproximal supports, wherein moving the proximal supports displaces a cooling surface of the cooling assembly to adjust the convergence profile of the casting cavity at the proximal region; and adjusting the convergence profile of the casting cavity at the distal region includes, for each of the opposing pair of cooling assemblies, moving at least one distal support, wherein moving the at least one distal support displaces the cooling surface of the cooling assembly to adjust the convergence profile of the casting cavity at the distal region. In some cases, the method further comprises determining a desired casting profile, wherein determining the desired casting profile is based on at least one casting parameter, and wherein adjusting the convergence profile of the casting cavity at the proximal region includes using the desired casting profile. In some cases, adjusting the convergence profile of the casting cavity at the proximal region occurs during a casting process.

In any of the aforementioned cases, the molten metal can be an aluminum alloy. In some cases, the aluminum alloy can have a Magnesium content at or above <NUM>% by weight based on the total weight of the alloy. In some cases, the Magnesium content is at or above <NUM>% by weight. In some cases, the Magnesium content is at or above <NUM>% by weight. In some cases, the Magnesium content is at or above <NUM>% by weight.

Also disclosed is a continuously cast article made according to the aforementioned methods and/or using the aforementioned systems or apparatuses.

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

Certain aspects and features of the present disclosure relate to a continuous casting device having multi-stage convergence control. The moving, cooling surfaces of the continuous casting device can be articulated in multiple stages to provide individual convergence control to longitudinally spaced-apart regions of the casting cavity. In a first (e.g., proximal) region, during which the molten metal exhibits solidification shrinkage, a first convergence profile (e.g., having a first rate of convergence) can be used to optimally account for the solidification shrinkage. In a second (e.g., distal) region, after the first region, a second convergence profile (e.g., having a second rate of convergence) can be used, such as to provide optimal control of the exit temperature of the continuously cast article. Multi-stage convergence control is achieved, according to an embodiment of the invention, through individually articulatable cooling pads positioned opposite the cooling surfaces from the casting cavity. Actuation of the individually articulatable cooling pads can effect different convergence profiles along the length of the continuous casting device.

As used herein, the meaning of "a," "an," and "the" includes singular and plural references unless the context clearly dictates otherwise. As used herein, the terms "top" and "bottom" can be associated with vertical positions when the continuous casting device is casting in a horizontal direction. However, in some cases, the continuous casting device may be used in a non-horizontal direction, 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 can include a pair of opposing cooling assemblies forming 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 molten metal within the casting cavity, as well as additional equipment related to operation of the cooling surface or cooling assembly (e.g., cooling pads, motors, coolant piping, sensors, and other such equipment).

Some continuous casters, such as belt casters, can consist of two counterrotating belts (e.g., opposing cooling surfaces) that, along with side dams, form a casting cavity into which molten metal can be fed. The belts can be water-cooled (e.g., cooled with deionized water) or cooled using other fluids. Molten metal entering the casting cavity at an entrance to the casting cavity can solidify, through heat extraction via the cooled belts, as it moves distally towards the exit of the casting cavity, where it exits as solidified metal (e.g., a continuously cast article). The metal can move through the casting device at approximately the same rate of movement of the belts, thus minimizing or eliminating shear forces between the solidifying metal and the belts.

As the metal cools and solidifies, it can shrink in volume. For example, Aluminum may shrink approximately <NUM>-<NUM>% by volume, which is known as solidification shrinkage. Solidification shrinkage may occur over the first <NUM> to <NUM> from the location where the molten metal comes into contact with the belts, although it may occur over other ranges, as well, including sub-ranges of <NUM> - <NUM>. If the casting cavity were parallel (e.g., having parallel belts, or zero convergence rate), the solidifying metal may lose contact with the cooled belts, particularly the top belt, at which point the heat transfer coefficient for extracting heat from the solidifying metal may rapidly decrease significantly (e.g., by orders of magnitude). This loss of contact can lead to undesirable effects, such as surface reheating, re-melting, or surface exudation. Current convergence control techniques can be used to control exit temperature and thickness of the as-cast metal article, however they do not account for the shrinkage during solidification. These current convergence control techniques often involve tilting the moving metal belts, as well as its driving apparatus, such that the cooling surfaces of the top and bottom belts at the casting cavity lie in intersecting planes which intersect at a point distal of the casting cavity. In other words, the height of the casting cavity decreases at a constant rate (e.g., constant rate of convergence) from the proximal end to the distal end of the casting cavity. However, certain aspects of the present disclosure can provide multi-stage convergence control, capable of accounting for solidification shrinkage, while also performing the other aspects of current dynamic convergence control techniques. This multi-stage convergence control can achieve dynamic rates of convergence along the length of the casting cavity, thus effecting a convergence cavity with multiple convergence profiles.

In some cases, this multi-stage convergence control can be achieved through cooling pads positioned opposite the cooling surfaces (e.g., continuous belts) from the casting cavity. In some cases, the cooling pads can be adjusted before a casting process and secured in place. In some cases, the cooling pads can be pre-formed to achieve a multi-stage convergence profile. In such cases, the cooling pads may or may not be movable.

In some cases, the cooling pads can be actuated by any suitable actuator, such as a linear actuator like a motor-driven, hydraulic, pneumatic, or other type of actuator. In some cases, each cooling pad can pivot about a pivot point or fulcrum to effect the desired convergence profile in the casting cavity by adjusting the contour of at least one of the cooling belts. In some cases, the actuator can be adjustable during the casting process. In some cases, the actuator can be dynamically adjustable during the casting process based on sensor feedback. The actuator can be coupled to a controller that can receive sensor data and make a determination with respect to the position of one or more of the cooling pads to achieve a desired result. For example, a temperature sensor coupled to the controller can provide information about temperatures within the casting cavity, on the cooling surfaces, and/or on the continuously cast article exiting the casting cavity. These temperatures can be used to determine if one or more of the cooling pads should be moved or adjusted to maintain or achieve a desired surface quality. Other sensors can be used.

In some cases, the cooling pads can include multiple nozzles located along a surface of the cooling pad and arranged in a pattern, such as a hexagonal or other pattern. In some cases, a cooling pad can include at least one linear nozzle extending across the width of the cooling pad and/or substantially or entirely across a width of the casting cavity.

Control of a cooling surface's contour, and thus the convergence profile of the casting cavity, is described herein with reference to the use of cooling pads to apply pressure to displace the cooling surface (e.g., continuous belt). However, in some cases, an alternate support other than a cooling pad can be used, such as a low-friction surface (e.g., Teflon-coated surface) or a moving surface (e.g., an articulatable roller).

Certain aspects and features of the present disclosure can be especially suitable for continuous belt casting devices, in which the cooling surfaces of opposing cooling assemblies are continuous metal belts that move with the solidifying metal in the casting cavity during casting. For clarity and illustrative purposes, certain aspects of the present disclosure will be described with reference to a continuous belt caster, however these aspects may be applicable to other continuous casting devices, as appropriate.

The multi-articulated design as disclosed herein allows a cooling surface of a continuous casting device to remain in constant or substantially constant contact with the solidifying surface of the metal within the casting device. Certain aspects and features of the present disclosure include, for each cooling belt, multiple cooling pads or other articulatable surfaces capable of adjusting the distance between the cooling belt and the center of the casting cavity. Since cooling pads can be used to extract heat from the cooling belt, it is provided to use multiple articulating or actuatable cooling pads to effect the different rates of convergence of the cooling belt along the length of the casting cavity. The multiple cooling pads or other articulatable surfaces allow the convergence profile of the casting cavity to be separately adjusted in a first region and a second region, such as a proximal region and a distal region. Multiple cooling pads can be separately adjusted to achieve a steeper convergence rate in a proximal region (e.g., a first region at or near the molten metal entrance to the casting cavity) to account for the relatively higher rate of contraction in that region and to achieve a shallower convergence rate in a distal region (e.g., a second region at or near the solidified metal exit of the casting cavity) to account for the relatively lower rate of contraction in that region. Thus, a risk of undesirable surface-related defects can be minimized.

Certain aspects of the present disclosure can improve as-cast surface quality of a continuously cast metal article. Any suitable metal can be used, however certain aspects of the present disclosure are especially suitable for casting aluminum alloys. In some cases, certain aspects of the present disclosure are especially suitable for casting aluminum alloys having high magnesium content (e.g., at or above <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% Mg by weight), and can help inhibit or eliminate the forming of beta film, at least at or near the surface of the continuously cast article.

The continuously cast article can have any suitable thickness, determined at least in part by the size of the casting cavity between the cooling surfaces of the continuous caster. The continuously cast article can be a metal strip, although the continuously cast article may be of other sizes (e.g., plate or shate).

As used herein, a plate generally has a thickness of greater than about <NUM>. For example, a plate may refer to an aluminum product having a thickness of greater than <NUM>, greater than <NUM>, greater than <NUM>, greater than <NUM>, greater than <NUM>, greater than <NUM>, greater than <NUM>, greater than <NUM>, or greater than <NUM>.

As used herein, a shate (also referred to as a sheet plate) generally has a thickness of from about <NUM> to about <NUM>. For example, a shate may have a thickness of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

As used herein, a sheet generally refers to an aluminum product having a thickness of less than about <NUM>. For example, a sheet may have a thickness of less than <NUM>, less than <NUM>, less than <NUM>, less than <NUM>, less than <NUM>, less than <NUM>, or less than <NUM>.

Certain aspects of the present disclosure relate to a continuous casting device having multiple-stage convergence control. In some cases, the number of convergence stages is two, although more than two stages can be used. A first, or proximal, stage can be adjustable to account for the shrinkage of the molten metal entering the continuous caster as it first solidifies. An additional, or distal, stage can be adjustable to control removal of the sensible heat, thereby controlling the exit temperature from the continuous caster.

All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of "<NUM> to <NUM>" should be considered to include any and all subranges between (and inclusive of) the minimum value of <NUM> and the maximum value of <NUM>; that is, all subranges beginning with a minimum value of <NUM> or more, e.g. <NUM> to <NUM>, and ending with a maximum value of <NUM> or less, e.g., <NUM> to <NUM>.

The continuously cast article can be processed by any means known to those of ordinary skill in the art. Such processing steps include, but are not limited to, homogenization, hot rolling, cold rolling, solution heat treatment, and an optional pre-aging step.

Optionally, the continuously cast article can be allowed to cool to a temperature between <NUM> to <NUM>. For example, the continuously cast article can be allowed to cool to a temperature of between approximately <NUM> to approximately <NUM> or from approximately <NUM> to approximately <NUM>. The continuously cast article can then be hot rolled at a temperature between approximately <NUM> to approximately <NUM> to form a hot rolled plate, a hot rolled shate or a hot rolled sheet having a gauge between <NUM> and <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or anywhere in between). During hot rolling, temperatures and other operating parameters can be controlled so that the temperature of the hot rolled intermediate product upon exit from the hot rolling mill is no more than approximately <NUM>, no more than approximately <NUM>, no more than approximately <NUM>, or no more than approximately <NUM>.

In some cases, the plate, shate or sheet can then be cold rolled using conventional cold rolling mills and technology into a sheet. The cold rolled sheet can have a gauge between about <NUM> to <NUM>, e.g., between about <NUM> to <NUM>. Optionally, the cold rolled sheet can have a gauge of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. The cold rolling can be performed to result in a final gauge thickness that represents a gauge reduction of up to <NUM> % (e.g., up to <NUM> %, up to <NUM> %, up to <NUM> %, up to <NUM> %, up to <NUM> %, up to <NUM> %, up to <NUM> %, up to <NUM> %, or up to <NUM> % reduction). Optionally, an interannealing step can be performed during the cold rolling step. The interannealing step can be performed at a temperature of from about <NUM> to about <NUM> (e.g., about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>). In some cases, the interannealing step comprises multiple processes. In some non-limiting examples, the interannealing step includes heating the plate, shate or sheet to a first temperature for a first period of time followed by heating to a second temperature for a second period of time. For example, the plate, shate or sheet can be heated to about <NUM> for about <NUM> hour and then heated to about <NUM> for about <NUM> hours.

Subsequently, the plate, shate or sheet can undergo a solution heat treatment step. The solution heat treatment step can be any conventional treatment for the sheet which results in solutionizing of the soluble particles. The plate, shate or sheet can be heated to a peak metal temperature (PMT) of up to about <NUM> (e.g., from about <NUM> to about <NUM>) and soaked for a period of time at the temperature. For example, the plate, shate or sheet can be soaked at about <NUM> for a soak time of up to about <NUM> minutes (e.g., <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, or <NUM> minutes).

After heating and soaking, the plate, shate or sheet is rapidly cooled at rates greater than about <NUM>/s to a temperature between approximately <NUM> and <NUM>. In one example, the plate, shate or sheet has a quench rate of above <NUM>/second at temperatures between approximately <NUM> and <NUM>. Optionally, the cooling rates can be faster in other cases.

After quenching, the plate, shate or sheet can optionally undergo a pre-aging treatment by reheating the plate, shate or sheet before coiling. The pre-aging treatment can be performed at a temperature of from about <NUM> to about <NUM> for a period of time of up to <NUM> hours. For example, the pre-aging treatment can be performed at a temperature of about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, or about <NUM>. Optionally, the pre-aging treatment can be performed for about <NUM> minutes, about <NUM> hour, about <NUM> hours, about <NUM> hours, about <NUM> hours, about <NUM> hours, or about <NUM> hours. The pre-aging treatment can be carried out by passing the plate, shate or sheet through a heating device, such as a device that emits radiant heat, convective heat, induction heat, infrared heat, or the like.

The cast products described herein can also be used to make products in the form of plates or other suitable products. For example, plates including the products as described herein can be prepared by casting a product in a continuous caster as disclosed herein followed by a hot rolling step. In the hot rolling step, the cast product can be hot rolled to a <NUM> thick gauge or less (e.g., from about <NUM> to about <NUM>). For example, the cast product can be hot rolled to a plate having a final gauge thickness of about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

The aluminum alloy products described herein can be used in automotive applications and other transportation applications, including aircraft and railway applications, or any other suitable application. For example, the disclosed aluminum alloy products can be used to prepare automotive structural parts, 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. The aluminum alloy products and methods described herein can also be used in aircraft or railway vehicle applications, to prepare, for example, external and internal panels.

The aluminum alloy products and methods described herein can also be used in electronics applications. 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, the aluminum alloy products can be used to prepare housings for the outer casing of mobile phones (e.g., smart phones), tablet bottom chassis, and other portable electronics.

These illustrative examples are given to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative embodiments but, like the illustrative embodiments, should not be used to limit the present disclosure. The elements included in the illustrations herein may not be drawn to scale. Specifically, the angles of attack illustrated herein have been exaggerated for illustrative purposes.

<FIG> is a side view schematic diagram depicting a continuous casting device <NUM> according to certain aspects of the present disclosure not pertaining to the present invention. The continuous casting device <NUM> includes a top belt assembly <NUM> and a bottom belt assembly <NUM> between which a casting cavity <NUM> is located. Each of the top belt assembly <NUM> and the bottom belt assembly <NUM> can include a cooling belt <NUM>, a proximal support <NUM>, and a distal support <NUM>. In some cases, proximal support <NUM> can be a proximal cooling pad, which is used to extract heat from the cooling belt <NUM>. In some cases, distal support <NUM> can be a distal cooling pad, which is used to extract heat from the cooling belt <NUM>. In cases where the proximal support <NUM> and/or the distal support <NUM> are not cooling pads, heat extracting from the cooling belt <NUM> can be achieved using other cooling elements, such as coolant nozzles, spray bars, or any other suitable cooling element. As used herein, the term "proximal" with reference to cooling pads, supports, or the like can refer to structures positioned at or near an entrance to the casting cavity <NUM>, such as where molten metal enters the casting cavity <NUM>. As used herein, the term "distal" with reference to cooling pads, supports, or the like can refer to structures positioned at or near an exit of the casting cavity <NUM>, such as where solidified metal exits the casting cavity <NUM>.

While <FIG> depicts a single proximal support <NUM> and a single distal support <NUM> for each of the top belt assembly <NUM> and bottom belt assembly <NUM>, other numbers of supports or cooling pads can be used as proposed by the present invention. According to the invention proximal support <NUM> and optionally also distal support <NUM> each comprises a plurality of supports and/or cooling pads, which can be configured to achieve a two-stage convergence profile. In some cases, additional supports (e.g., additional cooling pads) can be positioned between the proximal support <NUM> and distal support <NUM> to provide additional stages to the convergence profile, such as to achieve a three or more stage convergence profile.

The belt <NUM> can be made of any suitable thermally-conductive material, such as copper, steel, or aluminum. The belts <NUM> of the top belt assembly <NUM> and the bottom belt assembly <NUM> can rotate in opposite directions to one another, such that the surfaces of the belts <NUM> that come into contact with the liquid metal <NUM> in the casting cavity <NUM> move in a downstream direction <NUM>. The top belt assembly <NUM> and the bottom belt assembly <NUM> can further include additional equipment as necessary, such as motors and other equipment.

Liquid metal <NUM> can enter the casting cavity <NUM> via nozzle <NUM>. Within the casting cavity <NUM>, the liquid metal <NUM> can solidify as heat is extracted via the belts <NUM> of the top belt assembly <NUM> and the bottom belt assembly <NUM>. The liquid metal <NUM> and solidifying liquid metal <NUM> move in direction <NUM> within the casting cavity. After sufficient heat has been extracted, the liquid metal <NUM> will have become solid and can exit the casting cavity <NUM> as a continuously cast article <NUM>. The continuously cast article <NUM> will exit the continuous casting device <NUM> at an exit temperature.

The casting cavity <NUM> is bounded by an entrance (e.g., at the nozzle <NUM>), an exit (e.g., where the continuously cast article <NUM> exits the casting cavity <NUM>), side dams, the top belt assembly <NUM>, and the bottom belt assembly <NUM>. More specifically, because the belts <NUM> of the top and bottom belt assemblies <NUM>, <NUM> are in motion, the top and bottom of the casting cavity <NUM> are bounded by the exterior surfaces <NUM> of the belts <NUM> that lie between the entrance and the exit of the casting cavity <NUM> at any particular point in time. The path of these exterior surfaces <NUM> can be adjusted, such as by pushing against them from within the top and bottom belt assemblies <NUM>, <NUM> (e.g., from opposite the belts <NUM> from the casting cavity <NUM>). As depicted in <FIG>, a proximal support <NUM> and a distal support <NUM> are located within each of the top and bottom belt assemblies <NUM>, <NUM>. The proximal support <NUM> and the distal support <NUM> can physically contact the belt <NUM> to define the path of the belt <NUM> and therefore the path of the exterior surface <NUM> of the belt <NUM>. The path of the exterior surfaces <NUM> of the belts <NUM> of the top and bottom belt assemblies <NUM>, <NUM> define a convergence profile for the casting cavity <NUM>.

The convergence profile is a representation of the height of the casting cavity <NUM> (e.g., distance between the exterior surfaces <NUM> of the belts <NUM>) across the length of the casting cavity <NUM> (e.g., longitudinal distance of the casting cavity <NUM> along direction <NUM>). Since the proximal support <NUM> and the distal support <NUM> are individually adjustable, the convergence profile of the casting cavity can have multiple zones, such as a proximal zone (e.g., a first zone) with a high, positive rate of convergence (e.g., quickly moving from a large height to a smaller height) and a distal zone (e.g., a second zone) with a low, negative rate of convergence (e.g., slowly moving from a first height to a slightly larger height).

In some cases, an optional controller <NUM> can be used to control the movement of the proximal support <NUM> and/or the distal support <NUM>, such as before and/or during a casting process. Controller <NUM> can be coupled to actuators associated with the proximal support <NUM> and/or the distal support <NUM>. Control paths from the controller <NUM> to the supports <NUM>, <NUM> are not depicted in <FIG> for clarity purposes. In some cases, each of the proximal support <NUM> and the distal support <NUM> is controllable by the controller <NUM>. However, in some cases, only the proximal support <NUM> is controllable by the controller <NUM>, and the distal support <NUM> is otherwise secured in place (e.g., prior to a casting process). By adjusting the position of the proximal support <NUM> and optionally the distal support <NUM>, the controller <NUM> can make adjustments to the convergence profile of the casting cavity <NUM>.

In some cases, the controller <NUM> can make adjustments to the convergence profile based on stored convergence profile information, with or without dynamic feedback. For example, controller <NUM> can have preset or modeled convergence profile information for a combination of particular casting parameters. Examples of casting parameters include alloy selection, as-cast continuously cast article height, and casting speed, although other casting parameters may be used. Preset convergence profile information can include convergence profile information that has been previously generated for a set of casting parameters and stored for later use. Modeled convergence profile information can include convergence profile information that is generated on demand based on inputted casting parameters. Convergence profile information can include initial settings for a convergence profile (e.g., for setting the convergence profile prior to a casting process) and optionally one or more additional settings for adjustments to the convergence profile during a casting process.

In some cases, the controller <NUM> can make dynamic changes to the convergence profile based on live feedback. Feedback can originate from various sensors and other equipment. For example, feedback related to casting speed can come from motors associated with the belts <NUM>. In some cases, sensors <NUM> can be coupled to the controller <NUM>. Sensors <NUM> can be temperature sensors or other types of sensors. Sensors <NUM> can provide live data to the controller <NUM> regarding the casting process, such as temperature of the belts <NUM>, exit temperature of the continuously cast article <NUM>, and/or other data. Sensors <NUM> can be placed in any suitable location, such as within a belt assembly <NUM>, <NUM> or adjacent the continuously cast article <NUM> near the exit of the casting cavity <NUM>.

<FIG> is a side view schematic diagram depicting the bottom half of a casting cavity <NUM> of a continuous casting device <NUM> according to certain aspects of the present disclosure not pertaining to the present invention. The continuous casting device <NUM> can be the continuous casting device <NUM> of <FIG>. The continuous casting device <NUM> is described in <FIG> as having cooling pads (e.g., proximal cooling pad <NUM> and distal cooling pad <NUM>), however in some cases, the continuous casting device <NUM> may use supports that are not cooling pads for one or both of the proximal cooling pad <NUM> and distal cooling pad <NUM>.

The bottom of the casting cavity <NUM> can be defined by the exterior surface <NUM> of the belt <NUM> of the bottom belt assembly. The casting cavity <NUM> can have a centerline <NUM> that extends through the center of the casting cavity <NUM> in a casting direction. A center plane of the casting cavity <NUM> can be defined by the centerline <NUM> and a lateral width of the casting cavity <NUM> (e.g., into and out of the page as seen in <FIG>).

A nosepiece <NUM> of a nozzle (e.g., nozzle <NUM> of <FIG>) can dispense liquid metal <NUM> into the casting cavity <NUM>. The liquid metal <NUM> can exit the nosepiece <NUM> and start to fill the casting cavity <NUM>, contacting the external surface <NUM> of the belt <NUM>. A meniscus <NUM> can form in the liquid metal <NUM> between the nosepiece <NUM> of the nozzle and the external surface <NUM> of the belt <NUM>. As the liquid metal <NUM> cools, it begins to solidify, until it has become a solid, continuously cast article <NUM> (e.g., a metal strip). A solidification distance <NUM> exists between where the liquid metal <NUM> first contacts the belt <NUM> and where the liquid metal <NUM> has fully solidified or has solidified sufficiently such that little or no solidification shrinkage will occur thereafter.

A liquid zone <NUM> can exist before the liquid metal <NUM> has solidified by any appreciable amount (e.g., less than <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% solid). A solid zone <NUM> can exist where the liquid metal <NUM> has substantially solidified (e.g., at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% solid) or fully solidified (e.g., at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% solid). A solidification zone <NUM> can exist between the liquid zone <NUM> and the solid zone <NUM>. The solidification distance <NUM> may be approximately or exactly the length of the solidification zone <NUM>. In some cases, the proximal cooling pad <NUM> exists in the solidification zone <NUM> and the distal cooling pad <NUM> exists in the solid zone <NUM>.

A proximal cooling pad <NUM> can contact the belt <NUM>. As used herein, the term "contact" when used with respect to a cooling pad contacting a belt can include contacting the belt through a layer of cooling fluid. The proximal cooling pad <NUM> can be positioned to displace the belt <NUM> from its otherwise expected path of travel. The proximal cooling pad <NUM> can be actuated to adjust the path of the belt <NUM> as desired. A distal cooling pad <NUM> can also contact the belt <NUM> and can also displace the belt <NUM> from its otherwise expected path of travel. In some cases, the distal cooling pad <NUM> can be actuated to adjust the path of the belt <NUM> as desired. In such cases, the distal cooling pad <NUM> can include associated elements to control its adjustment, as depicted with respect to the proximal cooling pad <NUM>.

As depicted in <FIG>, the proximal cooling pad <NUM> can be fixed about a pivot point <NUM>. Extension and/or retraction of actuator <NUM> in direction <NUM> can adjust an angle of attack <NUM> of the proximal cooling pad <NUM>. The angle of attack <NUM> can be an angle between the belt-contacting surface of the proximal cooling pad <NUM> and the centerline <NUM> (e.g., horizontal, in some cases). By extending or retracting actuator <NUM>, the angle of attack of the exterior surface <NUM> of the belt <NUM> can be adjusted due to the displacement of the belt <NUM> by the proximal cooling pad <NUM>. Thus, the proximal cooling pad <NUM> can be pivoted and the convergence profile and rate of convergence of the casting cavity <NUM> can be adjusted. Based on the casting parameters (e.g., alloy of the liquid metal <NUM>, casting speed, or others), the angle of attack <NUM> of the proximal cooling pad <NUM> can be adjusted to account for solidification shrinkage that occurs within a solidification zone <NUM>. Accounting for this solidification shrinkage can allow the surface of the solidifying metal to remain in contact with the external surface <NUM> of the belt <NUM>. In some cases, the proximal cooling pad <NUM> extends from at or upstream of the casting cavity <NUM> (e.g., at or upstream of the exit of the nosepiece <NUM>) to the end of the solidification distance <NUM>. In some cases, the proximal cooling pad <NUM> can end upstream or downstream of the end of the solidification distance <NUM>.

<FIG> depicts the proximal cooling pad <NUM> having an upstream pivot point <NUM> and a downstream actuator <NUM>, however any suitable combination and placement of actuators <NUM> and/or pivot points <NUM> can be used to achieve the desired actuatability of the proximal cooling pad <NUM>. For example, a proximal cooling pad <NUM> can be supported by multiple actuators <NUM> designed to operate independently to achieve a desirable angle of attack <NUM>.

In some cases, the proximal cooling pad <NUM> can further be adjustable in a longitudinal direction (e.g., in the casting direction). The top half of the continuous casting device <NUM> can be designed similarly to the bottom half as depicted and disclosed in <FIG>. In some cases, adjustments to the top and bottom cooling surfaces can be symmetric. However, in some cases, adjustments to the top and bottom cooling surfaces can be asymmetric to account for the asymmetric effects of gravity and heat flow.

As described herein, the distal cooling pad <NUM> can be fixed or adjustable similarly to the proximal cooling pad <NUM>. The proximal cooling pad <NUM> can be adjusted to account for solidification shrinkage that occurs within the solidification zone <NUM>. The distal cooling pad <NUM> can be fixed or adjustable to a position that results in a desired exit temperature of the continuously cast article <NUM>. It can be desirable to achieve a particular exit temperature to facilitate downstream processing and minimize the need for extra equipment, such as cooling device and heating devices.

<FIG> is a side view schematic diagram depicting the bottom half of a casting cavity <NUM> of a continuous casting device <NUM> with linear nozzle cooling pads according to certain aspects of the present disclosure and according to an embodiment of the present invention. The continuous casting device <NUM> can be the continuous casting device <NUM> of <FIG>. The continuous casting device <NUM> is described in <FIG> as having cooling pads (e.g., proximal cooling pad set <NUM> containing linear nozzles <NUM>, and distal cooling pad <NUM>), however in some cases, the continuous casting device <NUM> may use supports that are not cooling pads instead of any of the linear nozzles <NUM>, proximal cooling pad set <NUM>, or distal cooling pad <NUM>.

The bottom of the casting cavity <NUM> can be defined by the external surface <NUM> of the belt <NUM> of the bottom belt assembly. The casting cavity <NUM> can have a centerline <NUM> that extends through the center of the casting cavity <NUM> in a casting direction. A center plane of the casting cavity <NUM> can be defined by the centerline <NUM> and a lateral width of the casting cavity <NUM> (e.g., into and out of the page as seen in <FIG>).

A liquid zone <NUM> can exist before the liquid metal <NUM> has solidified by any appreciable amount (e.g., less than <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% solid). A solid zone <NUM> can exist where the liquid metal <NUM> has substantially solidified (e.g., at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% solid) or fully solidified (e.g., at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% solid). A solidification zone <NUM> can exist between the liquid zone <NUM> and the solid zone <NUM>. The solidification distance <NUM> may be approximately or exactly the length of the solidification zone <NUM>. In some cases, a proximal cooling pad set <NUM> exists in the solidification zone <NUM> and the distal cooling pad <NUM> exists in the solid zone <NUM>.

The proximal cooling pad set <NUM> includea two or more proximal cooling pads that contact the belt <NUM>. As depicted in <FIG>, the proximal cooling pad set <NUM> includes five cooling pads that are linear nozzles <NUM>, although other numbers of cooling pads and other styles of cooling pads may be used. The linear nozzles <NUM> can be positioned to displace the belt <NUM> from its otherwise expected path of travel. Each of the linear nozzles <NUM> can be actuated to adjust the path of the belt <NUM> as desired at individual locations within the solidification zone <NUM>. A distal cooling pad <NUM> can also contact the belt <NUM> and can also displace the belt <NUM> from its otherwise expected path of travel. In some cases, the distal cooling pad <NUM> can be actuated to adjust the path of the belt <NUM> as desired. In such cases, the distal cooling pad <NUM> can include associated elements to control its adjustment, as described herein, such as with respect to the proximal cooling pad <NUM> of <FIG>.

As depicted in <FIG>, the proximal cooling pad set <NUM> includes multiple linear nozzles <NUM>. In some cases not pertaining to the present invention, each of the linear nozzles <NUM> is fixed with respect to one another and the entire proximal cooling pad set <NUM> can be actuated as a whole, such as using any of the equipment and techniques for actuating proximal cooling pad <NUM> of <FIG>. According to the invention each of the linear nozzles <NUM> is individually adjustable to adjust the path of the belt <NUM> and therefore adjust the convergence profile of the casting cavity <NUM>. Each of the linear nozzles <NUM> can be coupled to an associated actuator (e.g., similar to actuator <NUM> of <FIG>) capable of adjusting the position of the linear nozzle <NUM>, and thus the path of travel of the belt <NUM>. Thus, the convergence profile and rate of convergence of the casting cavity <NUM> can be adjusted. Based on the casting parameters (e.g., alloy of the liquid metal <NUM>, casting speed, or others), the position of each of the linear nozzles <NUM> can be adjusted to account for solidification shrinkage that occurs within a solidification zone <NUM>. Accounting for this solidification shrinkage can allow the surface of the solidifying metal to remain in contact with the external surface <NUM> of the belt <NUM>. Because of the increased resolution available to a proximal cooling pad set <NUM> over a single proximal cooling pad, several different convergence rates can be present in the convergence profile in the solidification zone <NUM>. In some cases, the proximal cooling pad set <NUM> extends from at or upstream of the casting cavity <NUM> (e.g., at or upstream of the exit of the nosepiece <NUM>) to the end of the solidification distance <NUM>. In some cases, the proximal cooling pad set <NUM> can end upstream or downstream of the end of the solidification distance <NUM>.

In some cases, each, some, or all of the linear nozzles <NUM> can further be adjustable in a longitudinal direction (e.g., in the casting direction). The top half of the continuous casting device <NUM> can be designed similarly to the bottom half as depicted and disclosed in <FIG>. In some cases, the convergence profile of the casting cavity <NUM> can be symmetric along the centerline <NUM>. However, in some cases, the convergence profile of the casting cavity <NUM> is not symmetric along the centerline <NUM> to account for the asymmetric effects of gravity and heat flow.

As described herein, the distal cooling pad <NUM> can be fixed or adjustable similarly to the proximal cooling pad set <NUM>. In some cases, a distal cooling pad set can be used, comprising two or more individual cooling pads, such as linear nozzles. The proximal cooling pad set <NUM> can be adjusted to account for solidification shrinkage that occurs within the solidification zone <NUM>. The distal cooling pad <NUM> can be fixed or adjustable to a position that results in a desired exit temperature of the continuously cast article <NUM>. It can be desirable to achieve a particular exit temperature to facilitate downstream processing and minimize the need for extra equipment, such as cooling device and heating devices.

<FIG> is a side view schematic diagram depicting the bottom half of a casting cavity <NUM> of a continuous casting device <NUM> illustrating angles of attack according to certain aspects of the present disclosure. The continuous casting device <NUM> can be the continuous casting devices <NUM>, <NUM>, or <NUM> of <FIG>, <FIG>, or <FIG>, respectively. The supports or cooling pads and the solidifying metal are not depicted for illustrative purposes.

A nosepiece <NUM> of a nozzle (e.g., nozzle <NUM> of <FIG>) can dispense liquid metal into the casting cavity <NUM>, which can then fill the casting cavity <NUM> and solidify as it moves towards the exit of the continuous casting device <NUM>.

The path of travel of the belt <NUM> can be adjusted to change the convergence profile of the casting cavity <NUM>. According to the invention, the path of travel of the belt <NUM> is adjustable at least through the use of a plurality of individually movable supports or cooling pads to displace the belt <NUM>, such as described with reference to <FIG>. The belt <NUM> can be displaced sufficiently to achieve at least two stages, where each stage is associated with a particular convergence profile. The first stage <NUM> can be used while the solidifying liquid metal is undergoing solidification shrinkage, and therefore can exactly or approximately match the solidification zone <NUM> of <FIG>. The second stage <NUM> can be used after the metal is substantially or completely solidified, and therefore can exactly or approximately match the solid zone <NUM> of <FIG>.

The belt <NUM> can be displaced in the first stage <NUM> to achieve a first convergence rate. In some cases, the convergence rate is linear during the first stage <NUM> at an angle of attack α. The angle of attack α can be defined as the angle between the centerline <NUM> and the external surface <NUM> of the belt <NUM> in the first stage <NUM>. The belt <NUM> can be displaced in the second stage <NUM> to achieve a second convergence rate. In some cases, the convergence rate is linear during the second stage <NUM> at an angle of attack β. The angle of attack β can be defined as the angle between the centerline <NUM> and the external surface <NUM> of the belt <NUM> in the second stage <NUM>. When accounting for solidification shrinkage, the angle of attack a may be positive and thus the first convergence rate in the first stage <NUM> is positive (e.g., the height of the casting cavity decreases in the casting direction). In some cases, the angle of attack β may be negative and thus the second convergence rate in the second stage <NUM> is negative (e.g., the height of the casting cavity increases in the casting direction). However, in some cases, as depicted in <FIG>, the angle of attack β may still be positive, although it may be smaller than angle of attack α. The cooling pads or other actuatable surfaces may pivot about a first stage pivot point <NUM> to achieve the desired angle of attack α in the first stage <NUM> and pivot about a second stage pivot point <NUM> to achieve the desired angle of attack β in the second stage <NUM>.

In some cases, the convergence profiles may include more than two zones. In some cases, the convergence profile within a zone may include a non-linear profile (e.g., a non-linear rate).

<FIG> is a graphical depiction of a convergence profile <NUM> that is monotonically decreasing according to certain aspects of the present disclosure. The convergence profile <NUM> depicts the casting cavity height between the nosepiece and the exit of the casting cavity. The casting cavity height is the distance between the cooling surfaces (e.g., continuous belts) of the continuous casting device. Line <NUM> represents the surface of a belt, such as the external surface <NUM> of belt <NUM> of <FIG>. The convergence profile during a first stage <NUM> (e.g., during solidification to account for solidification shrinkage) is different than the convergence profile during a second stage <NUM> (e.g., after solidification).

Line <NUM> decreases linearly in the first stage <NUM> at a first rate and further decreases in the second stage <NUM> a different rate. The decrease in casting cavity height corresponds to a positive convergence rate, since the height decreases as the belts converge. The casting cavity height can decrease monotonically between the nosepiece and the caster exit. The rate of decrease of the casting cavity height during the first stage <NUM> can be larger than the rate of decrease during the second stage <NUM>.

<FIG> is a graphical depiction of a convergence profile <NUM> that includes a constant second stage <NUM> according to certain aspects of the present disclosure. The convergence profile <NUM> depicts the casting cavity height between the nosepiece and the exit of the casting cavity. The casting cavity height is the distance between the cooling surfaces (e.g., continuous belts) of the continuous casting device. Line <NUM> represents the surface of a belt, such as the external surface <NUM> of belt <NUM> of <FIG>. The convergence profile during a first stage <NUM> (e.g., during solidification to account for solidification shrinkage) is different than the convergence profile during a second stage <NUM> (e.g., after solidification).

Line <NUM> decreases linearly in the first stage <NUM> at a first rate and then remains constant during the second stage <NUM>. The decrease in casting cavity height corresponds to a positive convergence rate, since the height decreases as the belts converge. The casting cavity height can decrease monotonically during the first stage <NUM> and then remain constant throughout the second stage <NUM>.

<FIG> is a graphical depiction of a convergence profile <NUM> that includes a multi-part first stage <NUM> according to certain aspects of the present disclosure. The convergence profile <NUM> depicts the casting cavity height between the nosepiece and the exit of the casting cavity. The casting cavity height is the distance between the cooling surfaces (e.g., continuous belts) of the continuous casting device. Line <NUM> represents the surface of a belt, such as the external surface <NUM> of belt <NUM> of <FIG>. The convergence profile during a first stage <NUM> (e.g., during solidification to account for solidification shrinkage) is different than the convergence profile during a second stage <NUM> (e.g., after solidification).

Line <NUM> decreases in the first stage <NUM> at multiple, different rates before further decreasing in the second stage <NUM>. The decrease in casting cavity height corresponds to a positive convergence rate, since the height decreases as the belts converge. The convergence profile <NUM> can be achieved, according to the invention, using multiple proximal cooling pads or a proximal cooling pad set, such as described with reference to <FIG>. The rate of decrease of the casting cavity height can change according to the amount of solidification shrinkage occurring at respective longitudinal locations within the first stage <NUM>. The casting cavity height during the second stage <NUM> can be adjusted as necessary, such as decreasing at a linear rate.

<FIG> is a graphical depiction of a convergence profile <NUM> that depicts a non-linear first stage <NUM> and an increasing second stage <NUM> according to certain aspects of the present disclosure. The convergence profile <NUM> depicts the casting cavity height between the nosepiece and the exit of the casting cavity. The casting cavity height is the distance between the cooling surfaces (e.g., continuous belts) of the continuous casting device. Line <NUM> represents the surface of a belt, such as the external surface <NUM> of belt <NUM> of <FIG>. The convergence profile during a first stage <NUM> (e.g., during solidification to account for solidification shrinkage) is different than the convergence profile during a second stage <NUM> (e.g., after solidification).

Line <NUM> decreases in the first stage <NUM> at a gradually decreasing rate before increasing in the second stage <NUM>. The decrease in casting cavity height corresponds to a positive convergence rate, since the height decreases as the belts converge. The increase in casting cavity height corresponds to a negative convergence rate, since the height increases as the belts diverge. The convergence profile <NUM> in the first stage <NUM> can be achieved using multiple proximal cooling pads or a proximal cooling pad set, such as described with reference to <FIG>. The convergence profile <NUM> in the first stage <NUM> can be achieved using a plurality of proximal cooling pads having a non-linear surface exposed to the inner surface of the belt. For example, a cooling pad can be shaped to achieve a desired convergence profile. Such cooling pad can be further actuated to adjust the convergence profile as necessary.

As depicted in <FIG>, the height of the casting cavity can increase during the second stage <NUM>. This type of negative convergence (e.g., increase in casting cavity height) during the second stage <NUM> can be used in any of the other convergence profiles disclosed herein, such as convergence profiles <NUM>, <NUM>, <NUM>, of <FIG>, <FIG>, respectively. In some cases, this type of negative convergence can be used to achieve a desirable exit temperature of the continuously cast article as it exits the continuous casting device.

<FIG> is a flowchart depicting a process <NUM> for adjusting a continuous casting device having multiple convergence stages according to certain aspects of the present disclosure. The process <NUM> can be used to make adjustments to the continuous casting device <NUM> of <FIG>, or any suitable continuous casting device.

At optional block <NUM>, one or more casting parameters are provided to a controller. The controller can be any suitable device for controlling the actuators, as described herein, such as a processor, microprocessor, proportional-integral-derivative controller, proportional controller, or the like. Instructions for performing the actions performable by the controller, as well as any data accessible to the controller (e.g., stored convergence profiles), can be stored on one or more non-transitory machine-readable storage mediums or storage devices which can comprise, without limitation, local and/or network accessible storage, and/or can include, without limitation, a disk drive, a drive array, an optical storage device, a solid-state storage device such as a random access memory ("RAM") and/or a read-only memory ("ROM"), which can be programmable, flash-updateable and/or the like.

At block <NUM>, the desired convergence profile of the casting cavity can be determined. Determining the desired convergence profile can include retrieving a preset convergence profile using the casting parameter(s) provided at block <NUM>. Determining the desired convergence profile can include calculating, modeling, or estimating the desired convergence profile using the casting parameter(s) provided at block <NUM>. In some cases, determining the desired convergence profile can include starting from a generic, preset convergence profile generally acceptable for use with the continuous casting device associated with process <NUM>. In some cases, determining the desired convergence profile can include accessing current data associated with the continuous casting device or molten metal to be fed to the continuous casting device, such as through one or more sensors coupled to the controller.

At block <NUM>, the cooling surfaces of the continuous casting device are adjusted to achieve the desired convergence profile in the solidification zone. Block <NUM> includes adjusting the proximal supports or proximal cooling pads. Adjusting the proximal support or proximal cooling pad can include adjusting at least one of a proximal cooling pad set, such as at least one linear nozzle <NUM> of the proximal cooling pad set <NUM> of <FIG>. The adjustment performed at block <NUM> can result in a convergence profile of the casting cavity suitable to achieve continuous contact between the solidifying metal within the casting cavity and the cooling surfaces of the continuous casting device, despite solidification shrinkage.

At optional block <NUM>, the cooling surfaces of the continuous casting device are adjusted to achieve the desired convergence profile in at least a portion of the solid zone. Block <NUM> can include adjusting a distal support or distal cooling pad, such as distal support <NUM> of <FIG>. In some cases, adjusting the distal support or distal cooling pad can include adjusting at least one of a distal cooling pad set. The adjustment performed at block <NUM> can result in a convergence profile of the casting cavity suitable to achieve a desirable exit temperature of the continuously cast article exiting the continuous casting device. In some cases, the amount of adjustment needed at block <NUM> can depend on the adjustment made at block <NUM>. The adjustment at block <NUM> can occur simultaneously or sequentially with respect to the adjustment at block <NUM>.

At optional block <NUM>, sensor data can be received by the controller and used to determine an adjustment to the desired convergence profile. The determined adjustment can then be fed into block <NUM> and/or block <NUM> to adjust the convergence profile of the casting cavity. In some cases, the sensor data received at block <NUM> is temperature data associated with at least one of the casting cavity, the cooling assemblies (e.g., the cooling surfaces), and the continuously cast article as it exits the continuous casting device.

In some cases, sensor data related to the temperature of the casting cavity or the cooling surfaces, or sensor data related to the surface quality of the continuously cast article, can be used to make adjustments to the convergence profile in the solidification zone, while sensor data related to the temperature of the continuously cast article as it exits the continuous casting device can be used to make adjustments to the convergence profile in at least a portion of the solid zone.

In some cases, convergence can be indirectly monitored by measuring heat flux profiles using an array of thermocouples mounted at, near, or in the proximal cooling pad and/or the distal cooling pad(s). The array of thermocouples can include a plurality of thermocouples arranged across a width of the continuous casting device and a longitudinal length of the continuous casting device. The heat flux profile can drop off significantly when the belt loses contact with the solidifying metal. Improved contact with the cooling surface can be manifested as a smoother heat flux profile. Thus, feedback from the array of thermocouples can be used to provide feedback for making adjustments to the proximal cooling pad and optionally any distal cooling pads.

Claim 1:
A continuous casting apparatus (<NUM>; <NUM>) comprising:
an opposing pair of cooling assemblies defining a casting cavity (<NUM>; <NUM>) therebetween, the casting cavity (<NUM>; <NUM>) extending longitudinally between a proximal end for accepting molten metal (<NUM>) and a distal end for outputting solidified metal (<NUM>), wherein each of the opposing pair of cooling assemblies comprises a cooling surface (<NUM>) made of a thermally conductive material for extracting heat from the molten metal to form the solidified metal, and wherein each of the opposing pair of cooling assemblies comprises:
at least one proximal support (<NUM>) positioned opposite the cooling surface (<NUM>) from the casting cavity for displacing the cooling surface (<NUM>), wherein the at least one proximal support (<NUM>) is longitudinally positioned adjacent to the proximal end of the casting cavity (<NUM>; <NUM>), and wherein the at least one proximal support (<NUM>) is movable to adjust a convergence profile (<NUM>; <NUM>; <NUM>; <NUM>) of the casting cavity (<NUM>; <NUM>) in a proximal zone of the casting cavity, the convergence profile (<NUM>; <NUM>; <NUM>; <NUM>) depicting the distance between the cooling surfaces (<NUM>, <NUM>) as a function of a longitudinal position within the casting cavity (<NUM>; <NUM>); and
at least one distal support (<NUM>) positioned opposite the cooling surface (<NUM>, <NUM>) from the casting cavity (<NUM>, <NUM>) for displacing the cooling surface (<NUM>, <NUM>), wherein the at least one distal support (<NUM>) is longitudinally positioned between the at least one proximal support (<NUM>) and the distal end of the casting cavity (<NUM>, <NUM>),
wherein the at least one proximal support (<NUM>) includes a plurality of proximal supports (<NUM>), and wherein each of the plurality of proximal supports (<NUM>) is individually adjustable to adjust the convergence profile (<NUM>; <NUM>; <NUM>; <NUM>) of the casting cavity (<NUM>; <NUM>).