SYSTEMS AND METHODS FOR CONTROLLING VERTICAL FOLDS DURING DIRECT CHILL CASTING

FIELD OF THE INVENTION

This application relates to the casting of metals, and more particularly to systems and methods for controlling folds during casting.

BACKGROUND

During direct chill (DC) casting, and particularly during DC casting of aluminum alloys, there is a tendency of oxide film to fold on a rolling face of an ingot. Usually, such folds are cast on the rolling face in a vertical direction along a cast direction, and such folds are defects that are sometimes referred to as “vertical folds.” Such defects may be observed on aluminum alloys with a high magnesium content (e.g., in excess of 2 wt %), such as those used as can end stock (CES). For example, FIG. 11 illustrates an example of an ingot 1101 that is a 5182 aluminum alloy cast using a traditional DC casting process. As illustrated, the ingot 1101 includes vertical folds 1103 cast on a rolling face 1105 of the ingot 1101. Such folds 1103 may come in various forms, including periodic-type folds 1103A, centerline-type folds 1103B, and/or corner-type folds 1103C. Regardless of the type of fold 1103, these defects are deleterious to further processing because the defects must be removed prior to additional processing (e.g., prior to hot rolling), which causes material waste (e.g., due to more scalping required), and/or such folds may form a crack initiation point during casting operations.

SUMMARY

Embodiments covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various embodiments 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 in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim.

According to certain embodiments, a method of controlling vertical folds during casting includes determining a fold control parameter of a skim dam of a casting system. The method includes introducing molten metal into a mold cavity of a casting mold of the casting system and forming a molten sump while controlling the skim dam to have the fold control parameter.

According to various embodiments, a method of controlling vertical folds during casting includes introducing molten metal into a mold cavity of a casting mold of a casting system by introducing the molten metal to a molten sump of a solidifying ingot. The method includes controlling a calcium level as a first fold control parameter and controlling a skim dam as a second fold control parameter while introducing the molten metal.

According to some embodiments, a skim dam system for a casting system includes a skim dam and a control system for the skim dam. The control system may selectively control a skim dam submergence depth of the skim dam in a molten sump.

According to certain embodiments, a casting system includes a plurality of casting molds for receiving molten metal and a plurality of skim dams, where each skim dam is positionable within a corresponding casting mold. The casting system also includes a control system for jointly controlling a skim dam submergence depth of each skim dam in a molten sump in the corresponding casting mold.

Various implementations described herein may include additional systems, methods, features, and advantages, which cannot necessarily be expressly disclosed herein but will be apparent to one of ordinary skill in the art upon examination of the following detailed description and accompanying drawings. It is intended that all such systems, methods, features, and advantages be included within the present disclosure and protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The specification makes reference to the following appended figures, in which use of like reference numerals in different figures is intended to illustrate like or analogous components.

FIG. 1 illustrates a portion of a DC casting system according to embodiments.

FIG. 2 is another view of the DC casting system of FIG. 1.

FIG. 3 illustrates a skim dam and a skim dam control system of the DC casting system of FIG. 1 according to embodiments.

FIG. 4 illustrates the skim dam and the skim dam control system of FIG. 3 with support plates removed.

FIG. 5 is another view of the skim dam and the skim dam control system of FIG. 3 according to embodiments.

FIG. 6 is a sectional view of a wall of the skim dam of FIG. 3 according to embodiments.

FIG. 7 is top view of a plurality of skim dams relative to a mold of a DC casting system according to embodiments.

FIG. 8 illustrates a DC casting system with one of the skim dams of FIG. 7 according to embodiments.

FIG. 9 illustrates a DC casting system with another one of the skim dams of FIG. 7 according to embodiments.

FIG. 10 illustrates a DC casting system with another one of the skim dams of FIG. 7 according to embodiments.

FIG. 11 illustrates an ingot with vertical folds.

FIG. 12 illustrates a casting system according to embodiments.

FIG. 13 illustrates a casting system according to embodiments.

DETAILED DESCRIPTION

Described herein are systems and methods for controlling vertical folds cast on a rolling face of an ingot during DC casting and using at least one skim dam. Techniques include controlling one or more fold control parameters of the at least one skim dam of the casting system to control vertical folds on the ingot. Techniques may additionally include controlling one or more additional fold control parameters, which may include, but are not limited to, a calcium level, an ingot head level within the mold cavity, a casting speed, and/or a titanium carbide (TiC) level. In certain embodiments, controlling at least the skim dam may minimize and/or eliminate vertical folds in cast ingots, particularly in ingots with a high magnesium content. While possible to cast an ingot without folds by controlling a level of calcium in molten metal instead of using a skim dam during casting, the omission of a skim dam during casting is not presently preferred. In particular, skim dams advantageously capture oxides in the molten metal and also improve safety by minimizing operator intrusion. Thus, the techniques described herein may allow for the minimization or elimination of folds in an ingot while also enabling use of a skim dam during casting. Various other benefits and advantages may be realized with the systems and methods described herein, and the aforementioned benefits should not be considered limiting.

FIGS. 1-6 illustrate an example of a metal casting system 100 according to various embodiments. The metal casting system 100 includes one or more open-ended molds 102, a supply system 112, and a skim dam system 120.

The mold 102 includes a top end 104, a bottom end 106, and mold walls 108 defining a mold cavity 110. The mold 102 may be surrounded by a cooling jacket through which a cooling fluid such as water is continuously circulated to provide external chilling of the mold walls 108. A bottom block 160 (see FIG. 10) may be initially positioned within or proximate to the bottom end 106 of the mold cavity 110 to close the bottom end 106 of the mold cavity 110. In certain embodiments, and as illustrated in FIGS. 1 and 2, the mold cavity 110 may be a generally rectangular shape, although in other embodiments the mold cavity 110 may have various shapes as desired. While a single mold 102 is illustrated in FIGS. 1-6, in other embodiments, a metal casting system 100 may have any number of molds as desired. As an example and as discussed below, FIGS. 12 and 13 illustrate casting systems with a plurality of molds. In one non-limiting example, a casting system may include six to ten molds, although in other embodiments the casting system may include less than six molds or more than ten molds.

The supply system 112 may be various suitable devices or mechanisms for supplying molten metal to the mold cavity 110. In the embodiment illustrated, the supply system 112 includes a trough 114 and a spout 116 (see FIG. 2). A control pin 118 may be movable relative to and within the spout 116 to regulate and/or terminate a flow of molten metal through the spout 116.

The skim dam system 120 includes one or more skim dams 122 and optionally includes a skim dam control system 124. While a single skim dam 122 is illustrated in FIGS. 1-6, in other embodiments the skim dam system 120 may include a plurality of skim dams 122 (see, e.g., FIGS. 12 and 13). In certain embodiments, the skim dam 122 may be centered relative the spout 116, although in other embodiments the skim dam 122 may be positioned as desired. Referring the FIGS. 3-6, the skim dam 122 generally includes a wall 126 defining a closed perimeter and having a top end 128 and a bottom end 130. As illustrated in FIGS. 1 and 2, the skim dam 122 may be provided around the spout 116 to facilitate a distribution of molten metal that is introduced into the mold cavity 110 and/or to reduce the generation of metal oxides at an upper surface of head region of the molten metal during casting. In various embodiments, and as best illustrated in FIGS. 3-5, the skim dam 122 includes one or more support features 134 for engaging the control system 124. The number, location, and type of support features 134 illustrated should not be considered limiting. Optionally, the skim dam 122 includes at least two support features 134 provided at or adjacent to opposing ends of the skim dam 122. In the embodiment illustrated, the skim dam 122 includes two support features 134 proximate to a first end 135 of the skim dam 122 and two support features 134 proximate to a second end 137 of the skim dam 122.

The skim dam 122 illustrated in FIGS. 1-6 has a small rectangle shape or profile. However, the particular shape of the skim dam 122 illustrated in FIGS. 1-6 should not be considered limiting. FIG. 7 illustrates non-limiting examples of skim dams having a plurality of shapes or profiles, including the skim dam 122 having a first rectangle profile, a skim dam 222 having a second rectangle profile, a skim dam 322 having a bulged rectangle profile, and a skim dam 422 having an hour glass rectangle profile. FIG. 8 illustrates a casting system 800 casting an ingot 801 from a 5812 aluminum alloy where the casting system 800 is substantially similar to the casting system 100 except that the skim dam system 120 includes the skim dam 222. FIG. 9 illustrates a casting system 900 casting an ingot 901 from a 5812 aluminum alloy where the casting system 900 is substantially similar to the casting system 100 except that the skim dam system 120 includes the skim dam 322. FIG. 10 illustrates a casting system 1000 that is substantially similar to the casting system 100 except that the skim dam system 120 includes the skim dam 422. A bottom block 160 of the casting system 1000 is illustrated in FIG. 10.

Referring back to FIG. 7, each skim dam 122, 222, 322, and 422 has a length and a width. In certain embodiments, the skim dam 122 may have a greatest length and a greatest width, and the skim dam 122 may have a minimum distance between the dam walls 126 and the mold walls 108. The length and the width of the skim dam 222 may be less than the length and the width of the skim dam 122, and in certain embodiments, the length and the width of the skim dam 222 are a minimum length and a minimum width. In various embodiments, the skim dam 222 may have a maximum distance between the dam walls 126 and the mold walls 108 compared to the other skim dams. In the embodiment illustrated in FIG. 7, the length and the width of the skim dam 322 may be less than the skim dam 122 and greater than the skim dam 222. Compared to the skim dam 122, at least two of the dam walls 126 of the skim dam 322 may have a convex curvature that is greater than any curvature of the dam walls 126 of the skim dam 122. The length and the width of the skim dam 422 may be less than the length and the width of the skim dam 122 and/or the skim dam 322. Compared to the skim dam 122, at least two of the dam wall 126 of the skim dam 422 may have a concave curvature. The skim dams illustrated in FIG. 7 are for illustrative purposes only, and in other embodiments, the skim dam system 120 may include skim dams with various shapes or profiles as desired. In certain embodiments, and as discussed in detail below, the shape or profile of the skim dam 122 is controlled as a fold control parameter of the skim dam system 120.

Optionally, and as illustrated in FIG. 6, the dam wall 126 may include a tapered portion 132 between the top end 128 and the bottom end 130. When included, the tapered portion 132 may further facilitate distribution of molten metal and/or control of metal oxides. In some embodiments, and as discussed in detail below, the tapered portion 132 optionally may facilitate positioning of the skim dam 122 to a submergence depth within the molten metal in the mold cavity 110.

Referring to FIGS. 3-5, when included, the skim dam control system 124 may control a vertical position of the skim dam 122 relative to the mold 102. The skim dam control system 124 generally includes a rotating arm 136, a controller 138, and a support arm 140 extending from the rotating arm 136. The skim dam control system 124 optionally may include a connecting arm 142 connecting the support arm 140 with the skim dam 122. The number of rotating arms 136, controllers 138, support arms 140, and/or connecting arms 142 should not be considered limiting on the disclosure. For example, while FIGS. 3-5 illustrate the skim dam control system 124 with two rotating arms 136, two controllers 138, four support arms 140, and four connecting arms 142, in other embodiments, a single rotating arm 136 and a single controller 138 may be provided for a skim dam 122. Moreover, while the skim dam control system 124 is illustrated as controlling a single skim dam 122, in other embodiments, the skim dam control system 124 may be operably connected to a plurality of skim dams 122 such that the skim dam control system 124 controls a plurality of skim dams 122.

In certain embodiments, and as illustrated in FIG. 3, the skim dam control system 124 may be supported on one or more supports 146 of the casting system 100. In the embodiment illustrated, the supports 146 are plates, although in other embodiments the supports 146 may be various devices or mechanisms as desired.

Referring to FIGS. 4 and 5, each rotating arm 136 is rotatable about an axis 144. One or more mounting devices 149 optionally may support the rotating arm 136 on the support 146 while enabling rotation of the rotating arm 136. Optionally, and as illustrated in FIGS. 4 and 5, one or more of the rotating arms 136 includes a stopper 148 that defines an angle or rotation of the rotating arm 136 about the axis 144. In the embodiment illustrated, the stopper 148 includes opposing ends 150, 152 that selectively engage the support 146 based on rotation of the rotating arm 136 to limit rotation of the rotating arm 136 about the axis 144. However, the stopper 148 illustrated should not be considered limiting, and the stopper 148 may be various suitable devices or mechanisms for limiting rotation of the rotating arm 136 about the axis 144.

In certain embodiments, each rotating arm 136 is operably connected to a corresponding controller 138. In other embodiments, a single controller 138 may be operably connected to a plurality of rotating arms 136. The controller 138 may be various suitable devices or mechanisms for selectively rotating the rotating arm 136 about the axis 144. In one non-limiting example, the controller 138 may include a driving mechanism (e.g., an electric motor) and a gear reduction box for improved positioning of the skim dam 122. In one non-limiting example, the gear reduction box may be a 60:1 gear reduction box, although it need not be in other embodiments. Optionally, the controller 138 may include a processor and/or a memory as desired, although it need not in other embodiments. In some embodiments, the controller 138 may be communicatively coupled to a control device (e.g., a device with a processor and/or a memory and/or user interface), and the controller 138 may control rotation of the rotating arm 136 based on data or information received from the control device.

Each support arm 140 extends outwards from a corresponding rotating arm 136. In certain embodiments, each support arm 140 may extend substantially perpendicular to the axis 144 of the rotating arm 136. In embodiments with a plurality of support arms 140 extending form a rotating arm 136 as illustrated in FIGS. 3-5, the support arms 140 may be aligned along the axis 144. In various embodiments, each support arm 140 is fixed relative to the rotating arm 136 such that rotation of the rotating arm 136 relative to the axis 144 likewise rotates the support arm 140 relative to the axis 144.

The connecting arms 142 may connect the support arms 140 with the skim dam 122. In certain embodiments, the connecting arms 142 may rigidly connect the skim dam 122 with the support arms 140 and/or rotating arm 136 such that the skim dam 122 can be positioned as desired based on rotation of the rotating arms 136. Such a rigid connection may also allow for complete control of the position of the skim dam 122 in the head of the molten metal during the entire cast and/or selective lifting of the skim dam 122 out of the head of the ingot as desired. Referring to FIGS. 4 and 5, each connecting arm 142 includes a first end 156 and a second end 158 opposite from the first end 156. In some embodiments, a length of the connecting arms 142, or a distance between the first end 156 and the second end 158, is fixed; however, in other embodiments, the length of the connecting arms 142 may be adjustable as desired. The first end 156 may be pivotably connected to an end 154 of a corresponding support arm 140 that is spaced apart from the axis 144. In such embodiments, the pivotable connection between the connecting arm 142 and the corresponding support arm 140 may allow for the connecting arm 142 to maintain a vertical orientation while the support arm 140 is rotated about the axis 144. Various suitable devices or mechanisms may be used to pivotably connect the connecting arm 142 with the corresponding support arm 140. The second end 158 of each connecting arm 142 may be connected to a corresponding support feature 134 on the skim dam 122. In some embodiments, the second end 158 is connected to the corresponding support features 134 such that the connecting arm 142 is not pivotable relative to the skim dam 122.

In certain embodiments, and as discussed in detail below, a vertical height (or submergence depth) of the skim dam 122 relative to an upper surface of the molten metal within the mold cavity 110 may be controlled by the skim dam control system 124 as a fold control parameter. In some non-limiting examples, the skim dam control system 124 may control the submergence depth to be less than or equal to about 15 mm relative to the upper surface of the molten metal, such as less than or equal to about 13 mm, such as less than or equal to about 10 mm, such as less than or equal to about 7 mm. In one non-limiting example, the skim dam control system 124 may control the submergence depth of the skim dam 122 to be from about 3 mm to about 5 mm. In some embodiments, the skim dam control system 124 may control the submergence depth of the skim dam 122 by further centering the skim dam 122 relative to the spout 116. In various embodiments, the fixed support arms 140 and/or the fixed connecting arms 142 may provide improved control of the submergence depth of the skim dam 122 during casting.

In various embodiments, the skim dam control system 124 includes a sensor 162 (see FIG. 2) for detecting a position of the skim dam 122, and the position detected by the sensor 162 may be used by the skim dam control system 124 such that the skim dam 122 is at a desired height. Various suitable sensors at various locations may be utilized as the sensor. In one non-limiting embodiment, the sensor 162 may be a laser-based sensor. The sensor 162 may be communicatively coupled to a control device and/or to the controller(s) 138 such that the position detected by the sensor may be used to control the skim dam 122.

When a plurality of rotating arms 136 and/or controllers 138 are included with the skim dam control system 124, the rotating arms 136 may be operably coupled to each other such that a rate and/or direction of rotation of the rotating arms 136 is synced, and the skim dam 122 is selectively raised or lowered via the skim dam control system 124 while maintaining a generally horizontal orientation. However, in other embodiments, the skim dam control system 124 may be controlled as desired, including such that the skim dam 122 is angled and/or otherwise positioned relative to a horizontal plane as desired.

A method of casting an ingot using the casting system 100 includes supplying molten metal to the mold cavity 110 using the supply system 112 and with the bottom block 160 initially closing the bottom end 106 of the mold cavity 110. As the molten metal is introduced into the chilled mold 102, the molten metal solidifies in a region adjacent to the inner periphery of the mold 102, and the bottom block 160 is moved downwardly and/or away from the bottom end 106 of the mold 102. With an effectively continuous movement of the platform and correspondingly continuous supply of molten aluminum to the mold 102, an ingot of desired length may be produced, limited only by the space available below the mold 102. The ingot emerging from the bottom end 106 of the mold 102 during DC casting is externally solid but is still molten in its central core. In other words, the pool of molten metal within the mold 102 extends downwardly into the central portion of the downwardly moving ingot for some distance below the mold 102 as a sump of molten metal. This sump has a progressively decreasing cross-section in the downward direction as the ingot solidifies inwardly from the outer surface until its core portion becomes completely solid. A coolant fluid, such as water, is brought into direct contact with the outer surface of the advancing embryonic ingot directly below the mold, thereby causing direct chilling of the surface metal. This direct chilling of the ingot surface serves both to maintain the peripheral portion of the ingot in solid state and to promote internal cooling and solidification of the ingot.

In certain embodiments, the method includes controlling one or more fold control parameters of the casting system 100 while casting the ingot to control fold formation on the ingot. In some embodiments, the method includes controlling a plurality of fold control parameters while casting the ingot. In various embodiments, at least one fold control parameter of the casting system 100 is a fold control parameter of the skim dam system 120.

As previously mentioned, in some embodiments, the shape or profile of the skim dam 122 may be a fold control parameter. In certain embodiments, the shape or profile of the skim dam 122 is controlled to maximize the distance between the dam walls 126 and the mold walls 108 within the mold cavity 110. Referring to FIG. 7, in one non-limiting example, the skim dam is controlled to have the shape of the skim dam 222. In other embodiments, the shape of the skim dam may be controlled to be other shapes as the fold control parameter. In certain embodiments, the shape of the skim dam 122 is controlled in conjunction with at least one additional or alternative fold control parameter to control vertical folds in the ingot.

In various embodiments, the submergence depth of the skim dam 122 relative to the upper surface of the molten metal in the mold cavity 110 may be a fold control parameter. In such embodiments, the skim dam control system 124 may control the submergence depth of the skim dam 122 by raising or lowering the skim dam 122 within the mold cavity 110 and such that the skim dam 122 is at a predetermined submergence depth. In some non-limiting examples, the predetermined submergence depth may be from 0 mm to 15 mm, such as less than 13 mm, such as from about 3 mm to about 5 mm. In other embodiments, the submergence depth of the skim dam 122 may be controlled to be other submergence depths as the fold control parameter. Optionally, controlling the fold control parameters may include controlling both the shape of the skim dam and the submergence depth of the skim dam.

In various embodiments, the fold control parameters may include various other parameters including, but not limited to, a calcium level, an ingot head level within the mold cavity, a casting speed, and/or a TiC level.

In one non-limiting example, controlling the fold control parameter may include controlling a calcium level in the molten metal to be a predetermined calcium level. In this embodiment, controlling the calcium level may control a rate or amount of calcium that is introduced into the molten metal during casting. In one non-limiting example, the predetermined calcium level may be controlled to be from about 70 ppm-110 ppm, such as from about 90 ppm-105 ppm. In other embodiments, the calcium level may be less than 70 ppm and/or greater than 110 ppm and/or in combination with other fold control parameters.

In another non-limiting example, controlling the fold control parameter may include controlling the ingot head level within the mold cavity 110 to be at a minimum (e.g., a distance between the upper surface of the molten metal in the mold cavity 110 and the bottom end 106 of the mold cavity 110 is minimized). In one non-limiting example, controlling the ingot head level may include controlling the ingot head level to be from about 40 mm to about 50 mm, such as from about 42 mm to about 46 mm, such as about 44 mm. In other embodiments, the ingot head level may be controlled to be other heights as desired and/or in combination with other fold control parameters.

In a further non-limiting example, controlling the fold control parameter may include controlling the casting speed to be a predetermined casting speed. In one non-limiting example, the predetermined casting speed may be from about 50 mm/min. to about 70 mm/min., such as from about 56 mm/min. to about 65 mm/min., such as about 62 mm/min, such as about 60 mm/min. In other embodiments, the casting speed may be controlled to be other speeds as desired and/or in combination with other fold control parameters.

In another non-limiting example, controlling the fold control parameter may include controlling the TiC level in the molten metal to be a predetermined level. In this embodiment, controlling the TiC level may control a rate or amount of TiC that is introduced into the molten metal during casting. In one non-limiting example, the predetermined TiC level may be from about 0 ppm to about 10 ppm, such as from about 3 ppm to about 10 ppm, such as about 5 ppm to about 10 ppm, such as from about 3 ppm to about 5 ppm.

As mentioned, in certain embodiments, controlling one or more fold control parameters during casting may include controlling a plurality of fold control parameters. As one non-limiting example, controlling a plurality of fold control parameters may include controlling the skim dam to be the skim dam 322, controlling the calcium level to be 70 ppm-85 ppm, controlling the TiC level to be 0 ppm-5 ppm, controlling the submergence depth to be 10 mm-15 mm, controlling the casting speed to be 50 mm/min-60 mm/min., and controlling the head level to be 42 mm-46 mm. As another non-limiting example, controlling a plurality of fold control parameters may include controlling the skim dam to be the skim dam 422, controlling the calcium level to be 75 ppm-90 ppm, and controlling the submergence depth to be 3 mm-5 mm.

In one non-limiting example, the fold control parameters optionally may be controlled to minimize and/or eliminate vertical folds by at least one of reducing the skim dam submergence depth, maximizing a distance between the skim dam walls and the mold walls, reducing the head height, providing calcium at a levels between 92 ppm and 105 ppm, and/or optionally providing TiC at a level of 5 ppm or less. Various other combinations of fold control parameters may be controlled as desired, and the previous examples should not be considered limiting.

FIG. 12 illustrates a metal casting system 1200 that is substantially similar to the metal casting system 100 except that the metal casting system 1200 includes a plurality of molds 102A-C, each of which includes an associated skim dam 122A-C. In the particular embodiment of FIG. 12, the metal casting system 1200 includes three molds 102; however, in other embodiments, any number of molds may be utilized as desired. In the embodiment of FIG. 12, each skim dam 122A-C is controlled by a corresponding skim dam control system 124A-C. In these embodiments, the position of one skim dam may be controlled independently from another skim dam.

FIG. 13 illustrates a metal casting system 1300 that is substantially similar to the metal casting system 1200 except that a single skim dam control system 124 controls the skim dams 122A-C. In these embodiments, the positions of the skim dams 122A-C may be jointly controlled. In certain embodiments, the metal casting system 1300 may alloy for easier control and design by allowing for measurement and control based on one of the skim dams to be used to approximate control for the other skim dams (i.e., each skim dam need not necessarily be independently measured). As an example, the rotating arm 136 of the skim dam control system 124 may extend across the plurality of molds 120A-C, and a plurality of support arms 140 may extend from the rotating arm 136. A plurality of connecting arms 142 may also be included connecting a corresponding support arm 140 to one of the skim dams 122A-C. In this manner, the common rotating arm 136 may be connected to each of the skim dams 122A-C, and rotation of the rotating arm 136 positions the plurality of skim dams 122A-C relative to the rotating arm 136. Various other connections or controls may be implemented in other embodiments, and the aforementioned examples should not be considered limiting.

A collection of exemplary embodiments are provided below, including at least some explicitly enumerated as “Illustrations” providing additional description of a variety of example embodiments in accordance with the concepts described herein. These illustrations are not meant to be mutually exclusive, exhaustive, or restrictive; and the disclosure not limited to these example illustrations but rather encompasses all possible modifications and variations within the scope of the issued claims and their equivalents.

Illustration 1. A method of controlling vertical folds during casting, the method comprising: determining a fold control parameter of a skim dam of a casting system; and introducing molten metal into a mold cavity of a casting mold of the casting system and forming a molten sump while controlling the skim dam to have the fold control parameter.

Illustration 2. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the skim dam is a first skim dam, the mold cavity is a first mold cavity, the molten sump is a first molten sump, and the casting mold is a first casting mold, and wherein the method further comprises: introducing molten metal into a second mold cavity of a second casting mold of the casting system and forming a second molten sump while controlling the second skim dam in parallel with the first skim dam.

Illustration 3. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the fold control parameter comprises a skim dam submergence depth, and wherein controlling the skim dam comprises controlling the skim dam to be at a predetermined submergence depth within the molten sump.

Illustration 4. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the predetermined submergence depth is from 0 mm to 15 mm, inclusive.

Illustration 5. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the predetermined submergence depth is less than 13 mm.

Illustration 6. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the predetermined submergence depth is from 3 mm to 5 mm, inclusive.

Illustration 7. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the skim dam to be at the predetermined submergence depth further comprises centering the skim dam relative to a spout of the casting system for introducing the molten metal into the mold cavity.

Illustration 8. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the fold control parameter comprises a skim dam shape, and wherein controlling the skim dam comprises controlling the skim dam to be a predetermined shape.

Illustration 9. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the predetermined shape comprises at least one of: a first rectangle having a first length and a first width; a bulged rectangle having a second length and a second width; an hour glass rectangle having a third length and a third width; or a second rectangle having a fourth length and a fourth width, wherein the fourth length is less than the first length and the fourth width is less than the first width.

Illustration 10. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the predetermined shape comprises the second rectangle, and wherein the fourth length is a minimum length and the fourth width is a minimum width.

Illustration 11. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the fold control parameter is a first fold control parameter of the skim dam, wherein the first fold parameter comprises a skim dam submergence depth, and wherein the method further comprises controlling a second fold control parameter of the skim dam, and wherein the second fold parameter comprises a skim dam shape.

Illustration 12. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the fold control parameter is a first fold control parameter of the casting system, and wherein the method further comprises controlling a second fold control parameter of the casting system.

Illustration 13. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the second fold control parameter comprises at least one of a calcium level in the molten metal, an ingot head level within the mold cavity, a casting speed, or a titanium carbide level in the molten metal.

Illustration 14. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the method comprises controlling vertical folds during DC casting.

Illustration 15. A method of controlling vertical folds during casting, the method comprising: introducing molten metal into a mold cavity of a casting mold of a casting system, wherein introducing the molten metal comprises introducing the molten metal to a molten sump of a solidifying ingot; and controlling a calcium level in the molten metal as a first fold control parameter and controlling a skim dam as a second fold control parameter while introducing the molten metal.

Illustration 16. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the calcium level comprises controlling the calcium level to be 70-110 ppm, inclusive.

Illustration 17. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the calcium level comprises controlling the calcium level to be 90-105 ppm, inclusive.

Illustration 18. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the skim dam comprises controlling a shape of the skim dam.

Illustration 19. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the skim dam comprises controlling a skim dam submergence depth.

Illustration 20. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the skim dam submergence depth comprises controlling the skim dam submergence depth to be less than 13 mm.

Illustration 21. The method of any preceding or subsequent illustrations or combination of illustrations, wherein controlling the skim dam submergence depth comprises controlling the skim dam submergence depth to be 3-5 mm, inclusive.

Illustration 22. The method of any preceding or subsequent illustrations or combination of illustrations, wherein the method comprises controlling vertical folds during DC casting.

Illustration 23. A skim dam system for a casting system, the skim dam system comprising: a skim dam; and a control system configured to selectively control a skim dam submergence depth of the skim dam in a molten sump.

Illustration 24. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the control system comprises: a rotating arm rotatable about an axis; a controller configured to rotate the rotating arm about the axis; a support arm extending from the rotating arm, wherein the support arm is fixed relative to the rotating arm and rotatable with the rotating arm about the axis; and a connecting arm connecting the support arm and the skim dam, wherein rotation of the rotating arm positions the skim dam relative to the rotating arm.

Illustration 25. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the connecting arm is pivotably coupled to the support arm.

Illustration 26. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, further comprising a stopper on the rotating arm, wherein the stopper defines an angle of rotation of the rotating arm about the axis.

Illustration 27. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the control system further comprises a support, and wherein the stopper is configured to engage the support at first position corresponding to a maximum skim dam submergence depth of the skim dam and at a second position corresponding to a minimum skim dam submergence depth of the skim dam.

Illustration 28. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the connecting arm is adjustable such that a distance between the support arm and the skim dam is adjustable.

Illustration 29. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the support arm is a first support arm and the connecting arm is a first connecting arm, and wherein the control system further comprises a second support arm extending from the rotating arm and a second connecting arm connecting the second support arm with the skim dam.

Illustration 30. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the rotating arm is a first rotating arm, the support arm is a first support arm and the connecting arm is a first connecting arm, and wherein the control system further comprises a second rotating arm, a second support arm extending from the second rotating arm and a second connecting arm connecting the second support arm with the skim dam.

Illustration 31. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the skim dam is a first skim dam, wherein the skim dam system comprises a second skim dam, and wherein the control system is configured to selectively control a skim dam submergence depth of the second skim dam in the molten sump.

Illustration 32. A casting system comprising: the skim dam system of any preceding or subsequent illustrations or combination of illustrations; and a casting mold for receiving molten metal in a molten sump, wherein the skim dam is positionable within the casting mold.

Illustration 33. The casting system of any preceding or subsequent illustrations or combination of illustrations, wherein the casting system is a DC casting system.

Illustration 34. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, further comprising a sensor configured to detect a position of the skim dam, wherein the control system is configured to control the skim dam submergence depth of the skim dam based on the detected position from the sensor.

Illustration 35. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the sensor is laser-based.

Illustration 36. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, further comprising a rigid arm connected to the skim dam and a controller configured to move the rigid arm to control the skim dam submergence depth.

Illustration 37. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the controller comprises a motor and a gear reduction box.

Illustration 38. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the gear reduction box is a 60:1 gear reduction box.

Illustration 39. The skim dam system of any preceding or subsequent illustrations or combination of illustrations, wherein the control system further comprises: a plurality of skim dams; the connecting arm connecting the support arm and the plurality of skim dams, wherein rotation of the rotating arm positions the plurality of skim dams relative to the rotating arm.

Illustration 40. A casting system comprising: a plurality of casting molds for receiving molten metal; a plurality of skim dams, wherein each skim dam is positionable within a corresponding casting mold; and a control system configured to jointly control a skim dam submergence depth of each skim dam in a molten sump in the corresponding casting mold.

Illustration 41. The casting system of any preceding or subsequent illustrations or combination of illustrations, wherein the control system comprises: a controller; a rotating arm; a plurality of support arms extending from the rotating arm; and a plurality of connecting arms, each connecting arm connected to a corresponding support arm and a corresponding skim dam, wherein rotation of the rotating arm positions the plurality of skim dams relative to the rotating arm.

The subject matter of embodiments is described herein with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. Directional references such as “up,” “down,” “top,” “bottom,” “left,” “right,” “front,” and “back,” among others, are intended to refer to the orientation as illustrated and described in the figure (or figures) to which the components and directions are referencing. In the figures and the description, like numerals are intended to represent like elements. As used herein, the meaning of “a,” “an,” or “the” includes singular and plural references unless the context clearly dictates otherwise. All ranges disclosed herein are to be understood to encompass 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 beginning with a minimum value of 1 or more, e.g. 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10.

While the systems and methods described herein can be used with any metal, they may be especially useful with aluminum or aluminum alloys. In this description, reference is made to alloys identified by aluminum industry designations, such as “series” or “7xxx.” For an understanding of the number designation system most commonly used in naming and identifying aluminum and its alloys, see “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” or “Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot,” both published by The Aluminum Association.

The above-described aspects are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the present disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure, and all possible claims to individual aspects or combinations of elements or steps are intended to be supported by the present disclosure. Moreover, although specific terms are employed herein, as well as in the claims that follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described embodiments, nor the claims that follow.

SYSTEMS AND METHODS FOR CONTROLLING VERTICAL FOLDS DURING DIRECT CHILL CASTING

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