Patent Description:
The present disclosure relates to metallurgy generally and more specifically to improved mold corner heating during casting.

In the metal casting process, molten metal is passed into a mold cavity. For some types of casting, mold cavities with false, or moving, bottoms are used. As the molten metal enters the mold cavity, generally from the top, the false bottom lowers at a rate related to the rate of flow of the molten metal. The molten metal that has solidified near the sides can be used to retain the liquid metal and partially liquid metal in the molten sump. Metal can be <NUM>% solid (e.g., fully solid), <NUM>% liquid, and anywhere in between. The molten sump can take on a V-shape, U-shape, or W-shape, due to the increasing thickness of the solid regions as the molten metal cools. The interface between the solid and liquid metal is sometimes referred to as the solidifying interface.

In direct chill casting, water or other coolant is used to cool the molten metal as the metal solidifies into a metal ingot as the false bottom of the mold cavity lowers. The coolant can create a temperature gradient in the molten metal, with the molten metal near the mold walls having a lower temperature than the molten metal near the center of the mold. The cooler molten metal near the mold walls can form microstructures in the solidifying metal that can remain in the resulting metal ingot. These microstructures can result in defects in the ingot, for example, when the metal ingot is rolled. Removing these defects from the metal ingot can result in lost time and material. <CIT> describes an apparatus including a mold for accepting molten metal and a non-contact flow inducer for generating a changing magnetic field which induces molten flow in the molten metal. <CIT> describes an apparatus for stirring a molten metal in an open topped mould including means for producing a magnetic field which rotates about the vertical axis of the mould and penetrates down into the mould. <CIT> describes an electromagnetic stirring method.

The term embodiment and like terms are intended to refer broadly to all of the subject matter of this disclosure and the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the claims below. Embodiments of the present disclosure covered herein are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the disclosure and introduces some of the concepts that are further described in the Detailed Description section below. 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.

The present invention relates to an apparatus as defined in claim <NUM> and to a method as defined in claim <NUM>. Certain examples herein address systems and methods for generating heat in molten metal in a mold to prevent or reduce intermetallics from forming in the molten metal. Various examples utilize a mold having an opening formed by multiple sidewalls to receive and contain the molten metal. One or more magnetic rotors can be positioned above the mold in a corner region formed by the meeting of two or more of the sidewalls. The two or more sidewalls can meet and form a curved corner with a radius. In some cases, the magnetic rotor may have a radius that allows the magnetic rotor to be positioned near the corner radius of the mold. For example, the curvature of the magnetic rotor may match the curvature at the corner radius of the mold. The magnetic rotors can generate heat in the molten metal by inducing changing magnetic fields in the molten metal. Inducing changing magnetic fields in the molten metal can create flow and electric current (e.g., eddy currents) in the molten metal to heat the molten metal. The one or more magnetic rotors may be configured to heat the molten metal of the molten metal in the corner region to a temperature above which intermetallics can form (e.g., above <NUM> degrees Celsius for a <NUM> alloy or a similarly desired temperature for other alloys to avoid forming melting intermetallics). The magnetic rotor positioned near the corner radius of the mold can localize the heating of the molten metal to a region directly adjacent to the mold wall at the corner radius (e.g., in a region that extends from the interior face of the corner radius to approximately <NUM> from the interior face of the corner radius). The magnetic rotor can be positioned and otherwise configured so the localized heating has little or no effect on the molten metal at or near the center of the mold, or away from the corners of the mold. The increase of the temperature above the temperature at which intermetallics can form can prevent or otherwise reduce formation of the intermetallics in the molten metal, for example, in the region adjacent to the corner radius.

In various examples, an apparatus is provided. The apparatus may include a mold and a magnetic rotor. The mold may have mold walls defining an opening for accepting molten metal. The mold walls may intersect to at least partially define a corner region of the opening. The magnetic rotor may be positioned adjacent to the corner region at a height above the molten metal when the molten metal is within the opening. The magnetic rotor may heat and induce a temperature increase in the molten metal within the corner region sufficient to prevent or otherwise reduce formation of the intermetallics in the molten metal at the corner region.

In various examples, a system is provided. The system may include a mold, a motor, and a magnetic source. The mold may have two or more sidewalls defining an opening for accepting molten metal. The two or more sidewalls may further define a corner region. The motor may be coupled with a drive shaft and positioned above the molten metal and adjacent to the corner region. The motor may rotate the drive shaft. The magnetic source may be coupled with the drive shaft and configured to induce heating of the molten metal adjacent to the corner region when rotated.

In various examples, a method is provided. The method may include depositing molten metal into a mold opening defined by two or more mold walls that may further define at least one corner region. Heat may be generated in the molten metal adjacent to the corner region by operating at least one magnetic rotor positioned adjacent to the corner region and above the molten metal. A temperature increase may be induced in the molten metal adjacent to the corner region sufficient to prevent or otherwise reduce formation of the intermetallics in the molten metal. The temperature increase may be caused by at least the heat generated by operating the at least one magnetic rotor.

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

The following examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof.

In this description, reference is made to alloys identified by AA numbers and other related designations, such as "series. " 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.

In traditional casting techniques for casting metal ingots, molten metal can be deposited into a mold through a mold opening. The molten metal can at least partially fill the mold and begin to cool, forming a metal ingot. The molten metal can cool at different rates; for example, the molten metal closer to the mold walls can cool at faster rate than the molten metal near the center of the mold. The difference in cooling rates can cause metal oxide layers to form in, on, or near the exterior layers of the ingot, for example, at or near the corners of the mold. During further processing operations of the ingot, for example, scraping and/or rolling of the ingot, the metal oxide layers can grow and/or separate from the ingot, leading to additional waste and/or processing.

In embodiments herein, systems and techniques relating to one or more magnetic rotors heating molten metal near the corners of a mold are described. The magnetic rotors can be positioned near the corner joints of the mold at a height above the molten metal. The magnetic rotors can rotate and induce moving or time varying magnetic fields within the molten metal in the mold corner. The changing magnetic fields can create eddy currents within the molten metal. The eddy currents can heat the molten metal by inducing metal flow in the mold corner and cause the temperature of the molten metal near the corner joints to increase to a temperature above the temperature at which intermetallics can form in the molten metal. As a result, intermetallics can be prevented from forming or the formation of intermetallics can otherwise be reduced near the corners of the ingot. Preventing intermetallics from forming or otherwise reducing such formation can save time and material during processing operations performed on the metal ingot (e.g., scraping and rolling operations). In some examples, the magnetic rotors can be positioned and otherwise configured so the localized heating has little or no effect on the molten metal at or near the center of the mold, or away from the corners of the mold.

Turning now to exemplary embodiments, <FIG> is a partial cut-away view of a metal casting system <NUM> including a mold <NUM> with magnetic rotors <NUM> in a vertical orientation (e.g., the rotation axis <NUM> of the magnetic rotors <NUM> is perpendicular to the top face of the mold). The mold <NUM> can form or define a mold opening <NUM> for receiving molten metal <NUM>, for example, from a launder <NUM> or other molten metal supply source. The magnetic rotors <NUM> can be positioned at or near the corner joints of the mold <NUM>. and heat the molten metal <NUM>, increasing the temperature of the molten metal in the mold above a temperature at which intermetallics can form.

The mold <NUM> can receive the molten metal <NUM><NUM> from the launder <NUM>, which can be positioned near the mold <NUM>. For example, the launder <NUM> may be positioned above the mold <NUM> and deposit molten metal into the mold opening <NUM> through a feed tube <NUM>. The launder <NUM> may include a flow control device <NUM> for adjusting the flow rate of the molten metal <NUM><NUM> from the launder <NUM> to the mold opening <NUM>.

In various embodiments, the mold <NUM> can include mold walls <NUM> (e.g., sidewalls), that define the mold opening <NUM> for receiving the molten metal <NUM>. The mold opening <NUM> can be a rectangular opening (e.g., a shape having two pairs of parallel sidewalls meeting at right angles) having one or more quadrants for receiving molten metal <NUM>. However, the mold opening <NUM> may be any suitable shape (e.g., circular or triangular). In various embodiments, the mold opening <NUM> can have rounded edges each having a rounded interior face. The mold walls <NUM> can be or include material that can withstand exposure to molten metal <NUM> and form the molten metal into various shapes and forms. A bottom block <NUM> can be positioned near the mold walls <NUM> to receive the molten metal <NUM> passing through the mold opening <NUM>. For example, prior to depositing molten metal <NUM> into the mold opening <NUM>, the bottom block <NUM> may be lifted to meet the mold walls <NUM>. Molten metal <NUM> can be deposited into the mold <NUM> and begin to cool, forming solidifying metal <NUM>. As the solidifying metal <NUM> beings to form within the mold <NUM>, the bottom block <NUM> can be steadily lowered, for example, by an actuator and/or telescoping hydraulic table. The solidifying metal <NUM> can form a casing around the molten metal <NUM>. As molten metal <NUM> is added to the top of the mold <NUM>, the bottom block <NUM> can continue to lower, continuously lengthening the solidifying metal <NUM>. In various embodiments, the mold walls <NUM> may include cooling elements to aid in the forming of solidifying metal <NUM>. For example, the mold walls <NUM> can define a hollow space containing a coolant <NUM>, such as water or glycol or other suitable coolant. The coolant <NUM> can exit from one or more of the mold walls <NUM> and flow down the sides of the solidifying metal <NUM> (e.g., from the mold <NUM> towards the bottom block <NUM>).

In various embodiments, one or more metal level sensors <NUM> can be positioned on or around the mold <NUM> to measure the height of the molten metal <NUM> and/or the solidifying metal <NUM> in the mold. In some cases, the structure and operation of the metal level sensor <NUM> is conventional. Other non-limiting options for the metal level sensor <NUM> may include a float and transducer, a laser sensor, or another type of fixed or movable fluid level sensor having desired properties for accommodating molten metal. In various embodiments the metal level sensors <NUM> may be coupled with one or more thermocouples and/or one or more infrared detection devices. The metal level sensors <NUM>, thermocouples, and/or infrared detection device may be used to create a closed-loop automation system to detect and/or react to unbalanced thermal conditions.

One or more magnetic rotors <NUM> can be can be positioned near the mold walls <NUM> for example, near the corners of the mold <NUM>. The magnetic rotors <NUM> can be positioned to heat the molten metal <NUM> received in the mold <NUM>. For example, a magnetic rotor <NUM> can be positioned in a corner region of the mold <NUM> to heat the molten metal <NUM> in and/or near the corner region. The magnetic rotors <NUM> can generate heat in the molten metal <NUM> by generating eddy currents that generate heat and induce flow in the molten metal. The magnetic rotors <NUM> can be sized and shaped so they are able to be positioned up against or adjacent a corner of the mold <NUM>. For example, when the corner of the mold <NUM> is rounded, the magnetic rotors <NUM> can have a circular cross section with a radius that matches the radius of the corner of the mold <NUM>. The circular cross section of the magnetic rotors <NUM> positioned adjacent to the rounded corner of the mold <NUM> can localize the effect of the magnetic rotors on the molten metal <NUM> such that the effect is wholly or partially contained within the corner region.

The magnetic rotors <NUM> can heat the molten metal <NUM> by inducing changing magnetic fields <NUM> (moving or time varying magnetic fields) within the molten metal <NUM> proximate the magnetic rotor <NUM>. The changing magnetic fields <NUM> create eddy currents within the molten metal <NUM> that generate heat and induce flow of the molten metal into the corner of the mold (shown in <FIG>). The eddy currents and induced flow can heat and/or keep (e.g., balance the thermal conditions of the molten metal <NUM>) at a temperature that prevents or otherwise reduces intermetallics from forming in the molten metal. The thermal conditions of the molten metal <NUM> can be balanced such that the Peclet and Biot numbers are balanced (e.g., the same amount of heat is supplied to the molten metal as is being extracted by the mold <NUM> at the corners). The molten metal <NUM> can be heated to and/or kept at a temperature that prevents or otherwise reduces intermetallics from forming in the molten metal and/or prevents the solidifying metal <NUM> from pulling away (e.g., freezing back) from the mold walls <NUM>. For example, when the molten metal <NUM> is a <NUM> alloy, the eddy currents can heat and/or keep the molten metal at a temperature above <NUM> degrees Celsius. The heating and maintaining of the molten metal <NUM> above the intermetallic formation temperature can prevent intermetallics from forming in the solidifying metal <NUM> and/or prevent the solidifying metal <NUM> from pulling away from the mold <NUM> and causing stress concentrations. The magnetic rotors <NUM> may heat and/or keep the molten metal <NUM> at a temperature in the range of approximately <NUM> degrees Celsius to <NUM> degrees Celsius (such as <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, or any value in between).

The magnetic rotors <NUM> can be positioned and/or oriented to localize the eddy currents (and the induced flow) in the molten metal <NUM>. For example, the magnetic rotors <NUM> may be positioned to generate eddy currents in a corner region of the mold <NUM> that generates heat and induces flow in the molten metal causing hot molten metal (e.g., at a temperature above the formation temperature of the intermetallics) to flow into the corners of the mold <NUM>.

The magnetic rotors <NUM> can be or include magnetic rotors that are positioned above the molten metal <NUM> at the corners of the mold <NUM> and can heat the molten metal without contacting the molten metal (e.g., non-contact magnetic rotors). However, the magnetic rotors <NUM> may be or include magnetic rotors that contact the surface of the molten metal <NUM><NUM> (e.g., contact magnetic rotors) and/or magnetic rotors that have at least a portion that is positioned beneath the surface of the molten metal (e.g., submergible magnetic rotors). The magnetic rotors <NUM> may additionally or alternatively include electromagnets, a heating element, and/or any device suitable for heating the molten metal <NUM>.

The magnetic rotors <NUM> may be suspended above the mold <NUM> using one or more of wires, chains, or other suitable devices. In various embodiments, the magnetic rotors <NUM> can be coupled to the launder <NUM> positioned above the mold <NUM> and/or coupled to the mold <NUM> itself. The magnetic rotors <NUM> can be suspended above the mold <NUM> to position a portion of the magnetic rotors in the range of <NUM> to <NUM> above the surface of the molten metal <NUM>.

The magnetic rotors <NUM> can be or include a rotation mechanism <NUM> and one or more magnets <NUM>. The magnetic rotors <NUM> can be rotated at various speeds, for example, at a speed in the range between <NUM> revolutions per minute (RPM) and <NUM> RPM. In various embodiments, the magnetic rotors <NUM> can be rotated at a speed that maximizes the heating of the molten metal <NUM> in the corner region. For example, the magnetic rotors <NUM> may be rotated at <NUM> RPM (<NUM>). The magnets can be or include permanent magnets, electromagnets, or any suitable magnetic device. The rotation mechanism <NUM> can be coupled with the magnets <NUM> to cause rotation of the magnets <NUM>. The rotation mechanism <NUM> can be or include a fluid motor that rotates the magnets <NUM> using a coolant fluid, such as air, allowing the same fluid to both cool the rotation mechanism and cause rotation of the magnetic source, for example, with a turbine or impeller. The rotation mechanism <NUM> may additionally or alternatively be or include an electric motor, fluid motors (e.g., hydraulic or pneumatic motors), adjacent magnetic fields (e.g., using an additional magnet source to induce rotation of the magnets of the magnetic source), or any suitable rotation mechanism.

In various embodiments, the magnetic rotors <NUM> can include an axle <NUM> connecting the rotation mechanism <NUM> with the magnets <NUM>. The magnets <NUM> can be rotationally fixed to the axle <NUM> (e.g., the permanent magnets rotate at the same speed as the axle) or the permanent magnets may be free to rotate with respect to the axle <NUM> (e.g., the permanent magnets can rotate around the center axle). The magnetic rotors <NUM> may additionally or alternatively rotate around a rotation axis <NUM>. The rotation axis <NUM> is perpendicular to a top face of the mold <NUM> (e.g., the magnetic rotors <NUM> are oriented in the vertical orientation). In some embodiments, the axle <NUM> may act as the rotation axis <NUM>.

Turning to <FIG>, a top view of a temperature profile of molten metal <NUM> in a known metal casting system <NUM> without magnetic rotors <NUM> is shown. The molten metal <NUM> located near the corners of the mold <NUM> has a lower temperature than the molten metal located near the center of the mold (e.g., depicted graphically in <FIG> by different types of shading). For example, the molten metal located near the mold walls can be at a temperature below <NUM> degrees Celsius and the temperature of the molten metal located near the center of the mold <NUM> can be at a temperature above <NUM> degrees Celsius. The lower temperature (e.g., below <NUM> degrees Celsius) of the molten metal <NUM> at the corners can be caused by heat being extracted from the molten metal by the two walls that form the corner. The extracting of the heat from the molten metal <NUM> can disrupt the balance of the Biot and Peclet numbers (i.e., more heat is extracted than supplied) and reduce the temperature of the molten metal <NUM> at the corners. The lower temperature of the molten metal <NUM> at the corners can allow an intermetallic layer to form in the molten metal <NUM> and/or a portion of the molten metal to solidify and retract away from the mold <NUM>. More specifically, the meniscus of the molten metal <NUM> can retract from the corners and freeze back; as the metal level increases, the meniscus builds further until the surface tension is broken and the metal can roll over the pre-frozen corner region, resulting in stress concentrations. The intermetallics and/or the stress concentrations can remain in the metal ingot formed by the metal casting system <NUM>, for example, beneath an oxide layer.

<FIG> are illustrations of a known metal ingot <NUM> formed using the metal casting system <NUM> without magnetic rotors <NUM><NUM>. <FIG> show a single face of the metal ingot <NUM>, however, the metal ingot may contain any number of faces. For example, the metal ingot <NUM> may be a rectangular prism with six faces. <FIG> shows one face of the metal ingot <NUM> having an oxide layer <NUM>. Although only one face of the metal ingot <NUM> is shown having an oxide layer <NUM>, the oxide layer can cover some or all of the faces of the ingot.

As shown in <FIG>, some or all of the oxide layer <NUM> can be removed from the metal ingot <NUM>, for example, by scraping or scalping the ingot. Removing the oxide layer <NUM> through scraping or scalping can leave some oxide layer on the edges of the metal ingot <NUM> where two or more of the metal ingot faces meet. The intermetallics formed during the casting process can be located within the metal ingot <NUM> beneath the intact oxide layer on the edges of the metal ingot <NUM>.

After removal of the oxide layer <NUM>, various rolling operations (e.g., hot rolling or cold rolling) can be performed on the metal ingot <NUM>. The temperature of the rolling operations can be performed at or cause the temperature of the metal ingot <NUM> to rise to a temperature above the melting temperature of the intermetallics and below the melting point of the metal ingot <NUM>, causing the intermetallics located beneath the oxide layer <NUM> to melt while the rest of the metal ingot remains intact. For example, the intermetallics can have a melting temperature of <NUM> degrees Celsius and the hot rolling temperature can be <NUM> degrees Celsius, causing the intermetallics in the metal ingot to melt while the other metal in the ingot remains solid on account of not exceeding a corresponding melting point of <NUM> degrees Celsius.

As shown in <FIG>, the melting of the intermetallics can cause a portion of the oxide layer <NUM> to separate from the metal ingot <NUM> and migrate from an edge to a face of the metal ingot. For example, the oxide layer <NUM> can be forced from the edge of the metal ingot <NUM> to a face of the metal ingot during the rolling operations. As shown in <FIG>, a portion of the oxide layer <NUM> can move from the edge of the face toward the center of the face and form what may be called a silver <NUM> on the face of the ingot. The oxide layer <NUM> on the face of the metal ingot <NUM> can result in additional processing operations (e.g., additional scalping and/or scraping operations) being performed on the metal ingot, which can result in additional processing time and/or additional material waste.

Turning now to <FIG>, a top view of the mold <NUM> and magnetic rotors <NUM> of <FIG> is shown, according to various embodiments. As shown, the exterior of the mold walls <NUM> can have a rectangular cross-section and the interior of the mold walls <NUM> can form a generally rectangular cross section with four rounded corners. The corners can each have a corner region <NUM> with one or more magnetic rotors <NUM> positioned above the corner region. However, the mold <NUM> may have any number of mold walls <NUM> forming any suitable cross-section and/or any number of magnetic rotors <NUM> positioned around the mold.

One or more of the rounded corners of the mold walls <NUM> can have a rounded interior face <NUM> oriented towards the center of the mold <NUM>. The rounded interior face <NUM> can have a radius <NUM>. The radius <NUM> can be sized and shaped to receive the magnetic rotors <NUM>. For example, at least one of the magnetic rotors <NUM> can have a circular cross-section with a radius <NUM> that matches the radius <NUM> of one or more of the corners of the mold <NUM>. The radius <NUM> and corresponding radius <NUM> can allow the magnetic rotor <NUM> to be positioned as close to the mold walls <NUM> as possible, while still being positioned above the molten metal <NUM>. For example, the rounded interior face <NUM> and the magnetic rotor <NUM> can be coaxial. The position of the magnetic rotor <NUM> can increase the effect of the magnetic rotor on the molten metal <NUM> in the corner region <NUM>, for example, by localizing the heating and/or the flow effect in the corner region.

The corner region <NUM> can stretch from one mold wall <NUM> to another mold wall. For example, the corner region <NUM> can are from a first mold wall 106A to a second mold wall 106B. The corner region <NUM> can have an area that is larger than the area of a cross-section of the magnet rotors <NUM>. However, the corner region <NUM> may have an area smaller than the area of a cross-section of the magnetic rotors <NUM> positioned next to the molten metal <NUM>.

In some embodiments, the corner region <NUM> can include a contact region <NUM>. The contact region <NUM> can be the molten metal <NUM> that is in contact with one or more of the mold walls <NUM>. In traditional molds without magnetic rotors <NUM>, the contact region <NUM> can be the region where intermetallics form.

The magnetic rotors <NUM> can be positioned and operated to localize heating of the molten metal <NUM> at or near the corner region <NUM> and/or the contact region <NUM>. The magnetic rotors <NUM> can increase or keep the temperature of the molten metal in the corner region <NUM> above <NUM> degrees Celsius. For example, the magnetic rotors <NUM> can rotate to create a flow <NUM> of hotter molten metal <NUM> (e.g., molten metal at a temperature above the formation temperature of intermetallics) to the corner regions <NUM>.

The magnetic rotors <NUM> can be optimized to partially or wholly localize the effect of the magnetic rotors at the corner region <NUM>. For example, the magnetic rotors <NUM> can increase or keep the temperature of the molten metal <NUM> in the corner region <NUM> by inducing magnetic fields that generate eddy currents in the molten metal. The eddy currents can generate heat and induce flow in the molten metal causing molten metal to flow into the corner region. In various embodiments, the effect of the magnetic rotors <NUM><NUM> can be further localized to be wholly or partially within the contact region <NUM>. For example, the magnetic rotors <NUM> may increase or keep the temperature of the molten metal in the corner region <NUM> above <NUM> degrees or other temperature that prevents intermetallics from forming in the corner region <NUM>.

In various embodiments, the magnetic rotors <NUM> can be moved to various positions above the molten metal <NUM> in the mold <NUM>. For example, a single magnetic rotor <NUM> may be moved to each of the corners to keep the temperature at all the corners above the temperature at which intermetallics form (e.g., approximately <NUM> degrees Celsius). In further embodiments, the magnetic rotors <NUM> may be moved to positions outside of the mold <NUM>, such that the rotors are positioned outside of the mold walls <NUM>. The magnetic rotors <NUM> may additionally or alternatively be moved between positions above the molten metal <NUM> and positions outside of the mold walls <NUM>, including, but not limited to positions over the mold walls.

In some embodiments, the magnetic rotors can be coupled to a height adjustment mechanism <NUM> (<FIG>, at left) that can be used to raise and lower the magnetic rotors <NUM> with respect to the mold <NUM>. The axle <NUM> may additionally or alternatively be or include the height adjustment mechanism <NUM>. During the casting process, it may be desirable to maintain a constant distance between the magnets <NUM> and the upper surface of the molten metal <NUM><NUM>. The height adjustment mechanism <NUM> can adjust the height of the magnets <NUM> in response to the raising or lowering of the molten metal <NUM>. For example, the height adjustment mechanism <NUM> can be connected to and/or coupled with the metal level sensor <NUM> to receive the height of the molten metal <NUM> and adjust the height of the magnets <NUM> based on the received height. The height adjustment mechanism <NUM> can be any mechanism suitable for adjusting the distance between the magnets <NUM> and the upper surface of the molten metal <NUM>, for example, an actuator.

The magnetic rotors <NUM> can heat the molten metal <NUM> by rotating one or more magnets <NUM> around the rotation axis <NUM> to generate a changing magnetic fields <NUM>. The changing magnetic fields <NUM> can induce current <NUM> in the molten metal <NUM>. The induced current <NUM> can generate heat and induce flow in the molten metal <NUM>. The one or more magnets <NUM> can be positioned in a range between <NUM> and <NUM> away from the surface of the molten metal <NUM>. The magnetic rotors <NUM> can rotate the magnets <NUM> around a rotational or rotation axis <NUM> that is generally perpendicular to a top face of the mold <NUM> (e.g., the magnetic rotors <NUM> are oriented in the vertical orientation). The magnets rotated by the magnetic rotors <NUM> oriented in the vertical orientation can focus the heating effect of the magnetic rotors at the corner regions <NUM> and/or the contact regions <NUM> as described above. For example, in the vertical orientation, the magnetic rotors <NUM> can localize the heat generation to raise the temperature of the molten metal <NUM> in the corner regions <NUM> and/or the contact regions <NUM> above <NUM> degrees Celsius (or other suitable temperature for avoiding the formation of intermetallics) with minimal or no temperature increase to the molten metal outside of the corner regions <NUM>.

The induced current <NUM> and resulting flow <NUM> and heat generation in the molten metal <NUM> can be controlled by controlling the magnetic rotors <NUM> to rotate the magnets <NUM> in various directions and/or at various speeds (e.g., the magnitude and/or direction or rotation can be adjusted). For example, the magnetic rotors can be rotated in a clockwise direction <NUM> or a counterclockwise direction <NUM>. The magnetic rotors <NUM> can all rotate in the same direction (e.g., the magnetic rotors can rotate clockwise <NUM>) or the magnetic rotors may rotate in multiple directions (e.g., a first magnetic rotor may rotate in a clockwise direction <NUM> and a second magnetic rotor may rotate in a counterclockwise direction <NUM>).

The magnetic rotors <NUM> can be rotated at a speed in the range of approximately <NUM> revolutions per minute (RPM) to approximately <NUM> RPM, which is equivalent to approximately <NUM> to approximately <NUM>. However, the magnetic rotors <NUM> may rotate at a suitable speed in the range of <NUM>-<NUM> RPM (such as <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, <NUM> RPM, or any value in between). In some embodiments, the speed of rotation of the magnetic rotors <NUM> can be optimized to localize the effect of the molten metal <NUM> at the corner regions. For example, the magnetic rotors <NUM> can rotate at or around <NUM> RPM to keep or heat the molten metal <NUM> in the corner regions <NUM> above a temperature at which intermetallics form (e.g., <NUM> degrees Celsius for some alloys). As discussed further in reference to <FIG>, the rotational speed of the magnetic rotors <NUM> can affect how much intermetallics are able to form in the corners.

The metal casting system <NUM> of <FIG> and <FIG> can be used to produce a metal ingot <NUM> (e.g., <FIG>). The metal ingot <NUM> can have an oxide layer <NUM>, similar to or the same as the oxide layer <NUM> shown in <FIG>. The metal ingot <NUM> can have the oxide layer <NUM> scraped or scalped using processes similar to or the same as processes used to scrape or scalp the metal ingot <NUM> shown in <FIG>. The metal ingot <NUM> can be rolled (e.g., hot or cold rolled) similar to or the same as the rolling of metal ingot <NUM> shown in <FIG>. However, unlike <FIG>, the oxide layer <NUM> at the edges of the metal ingot <NUM> in <FIG> has not broken off and been pushed to a face of the ingot, nor formed a sliver <NUM>. Using the magnetic rotors <NUM>, the intermetallics can be reduced (or prevented from forming) in the metal ingot <NUM>, allowing the oxide layer <NUM> to remain attached to the corners of the metal ingot during rolling operations and/or allowing avoidance of formation of slivers <NUM> during rolling operations.

Turning to <FIG>, profiles <NUM>, <NUM>, and <NUM>, respectively, are shown. The profiles <NUM>, <NUM>, <NUM> can depend on different speeds of rotation of the magnetic rotors <NUM>, however, the profiles may additionally or alternatively depend on the angle of the rotational axis <NUM>, the number of magnetic rotors, the strength of the magnets <NUM>, the number of permanent magnets, or combinations of these or other factors.

<FIG> illustrates an example of a profile <NUM> of a molten metal system without magnetic rotors <NUM>. Generally, the profile <NUM> is depicted relative to a vertical axis that denotes Second derivative of Differential Scanning Calorimeter scan (e.g., in W/g °C2) and a horizontal axis that denotes Temperature (°C). The profile <NUM> can include two peaks <NUM>, <NUM> at <NUM> and <NUM>. The peaks can indicate the type and size of particles that are precipitating or dissolving (e.g., shown by the temperature at the peak) and the amount of precipitation or dissolution (e.g., the area under the peak).

<FIG> illustrates an example of a profile <NUM> of a molten metal system with magnetic rotors <NUM> rotating at a rotation speed in the range of <NUM> to <NUM> RPMs, and <FIG> illustrates an example of a profile <NUM> of a molten metal system with magnetic rotors <NUM> rotating at a rotation speed in the range of <NUM> to <NUM> RPMs. As may be appreciated by comparing <FIG> with <FIG>, the profile <NUM> of <FIG> can have peaks <NUM>, <NUM> with a larger magnitude than those of profile <NUM> of <FIG>, while the profile <NUM> of <FIG> can have a single peak <NUM> that is larger than the corresponding peak <NUM> of <FIG>. Thus, changing the rotation speed of the magnetic rotors <NUM> can affect the magnitude of the peaks. The magnetic rotors <NUM> rotating at a certain rotation speed may cause the magnitude of the peaks to increase (e.g., peaks <NUM>, <NUM>, and <NUM>) or may cause the magnitude of peaks to decrease (e.g., as shown in <FIG> where one of the peaks has been eliminated). The changing size of the peaks may indicate the amount of precipitation or dissolution changing due to the area of the peak changing. Similarly, the changing peak can indicate the size and type of particles that are precipitating or dissolving may be changing due to the temperature at the peak changing.

Turning to <FIG>, a flowchart illustrating a process <NUM> of processing molten metal <NUM> using the metal casting system <NUM> of <FIG> is shown, according to various embodiments. Various blocks of the process <NUM> are described by referencing the components shown in <FIG> and <FIG>, however, additional or alternative components may be used with the process.

The process <NUM> at block <NUM> can include depositing molten metal (e.g., molten metal <NUM>) into a mold (e.g., mold <NUM>). The molten metal <NUM> can be deposited into the mold <NUM> through the mold opening <NUM>. A bottom block <NUM> of the mold <NUM> can be in a position to form a bottom of the mold <NUM> for receiving the molten metal <NUM>. The molten metal <NUM> can be deposited into the mold <NUM> from a launder <NUM> or other structure positioned above the mold.

The process <NUM> at block <NUM> can include generating heat in the molten metal <NUM> at a corner region <NUM> of the mold <NUM>. The heat can be generated using magnetic rotors (e.g., magnetic rotors <NUM>) positioned above the molten metal <NUM> in the corner region <NUM>. The magnetic rotors <NUM> can generate changing magnetic fields <NUM> in the molten metal <NUM>. The changing magnetic fields can in turn induce current <NUM> (e.g., eddy currents) in the molten metal <NUM>. The current <NUM> can generate heat and induce flow of the molten metal in the corner region <NUM> and/or at the contact region <NUM>. The generated heat and induced flow can heat the molten metal <NUM> to a temperature above the temperature at which the intermetallics can form (e.g., <NUM> degrees Celsius for certain alloys). The effect of the magnetic rotors <NUM> can be localized to the corner region <NUM> and/or the contact region <NUM>. For example, the magnetic rotors <NUM> can cause the temperature of the molten metal <NUM> in the corner region <NUM> and/or the contact region <NUM> to rise with minimal or no effect to the molten metal outside of the corner region <NUM> and/or the contact region <NUM>.

The process <NUM> at block <NUM> can include inducing a temperature increase in the molten metal <NUM> adjacent to the corner region <NUM>. The temperature increase at block <NUM> may result from the heat generated at block <NUM>. For example, the temperature increase can be caused by the heat generated and the flow induced by the current <NUM> induced by the magnetic rotors <NUM>. In various embodiments, the temperature increase can be localized to the corner region <NUM> and/or the contact region <NUM>. The temperature increase can heat the molten metal in the corner region <NUM> and/or the contact region <NUM> to a temperature that prevents intermetallics from forming. For example, the temperature in the corner region <NUM> and/or the contact region <NUM> can be increased to a temperature at or above <NUM> degrees Celsius or other suitable temperature, depending on the alloy being cast.

As used herein, the terms "invention," "the invention," "this invention," and "the present invention" are intended to refer broadly to all of the subject matter of this patent application and the claims below. The subject matter of embodiments of the present invention is described here 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. As used herein, the meaning of "a," "an," and "the" includes singular and plural references unless the context clearly dictates otherwise.

While certain aspects of the present disclosure may be suitable for use with any type of material, such as metal, certain aspects of the present disclosure may be especially suitable for use with aluminum.

Claim 1:
An apparatus (<NUM>) comprising:
a mold (<NUM>) comprising mold walls (<NUM>) defining an opening (<NUM>) for accepting molten metal (<NUM>), wherein an intersection of the mold walls at least partially define a corner region of the opening (<NUM>);
a magnetic rotor (<NUM>) adjacent to the corner region, wherein the magnetic rotor (<NUM>) is:
oriented to rotate one or more permanent magnets (<NUM>) around a rotational axis (<NUM>) that is perpendicular to a top face of the mold,
positioned at a height above the molten metal (<NUM>) when the molten metal is within the opening (<NUM>) defined by the mold (<NUM>), and
is configured to induce a current in the molten metal (<NUM>) within the corner region (<NUM>) to heat the molten metal within the corner region (<NUM>) to a temperature that inhibits formation of intermetallics.