Patent Description:
A variety of forming processes are useful for transforming flat metal substrates into shaped metal products. In a stamping process, a metal substrate is placed between stamping dies and a force is applied between the dies to form the metal substrate to plastically conform it to raises and recesses present in the stamping dies, typically without extensive thinning of the metal. An example stamping process may correspond to shaping of a sheet metal blank into an automobile door panel. In a drawing process, a metal substrate is placed between a die and a punch and a force is applied to drive the punch through the die and thin the metal as is it drawn into an extended shape. An example drawing process may correspond to shaping of a sheet metal blank into an aluminum cup as part of the can making process. In a roll-forming process, an elongated metal sheet is passed between rollers of a roll-forming stand to create a continuous bend along a length of the elongated metal sheet. Each of these forming processes provides complementary features that may not be available in the others, while there may be some features that can overlap. For example, suitably shaped stamping dies can include portions that draw a metal substrate into an extended shape while other portions can undergo plastic forming.

Some metals and alloys are easily formable, while others may not have suitable formability character. In some cases, formability and strength are inversely related, such that highly formable alloys may not exhibit high strength, while high strength alloys may not be easily formable and may simply fracture or rupture when subjected to forming processes that impart stress or strain beyond a fracture limit of the alloy. Thus, it may be difficult to form high-strength metal substrates into complex shapes.

<CIT>, which is considered to form the basis for the preambles of claims <NUM> and <NUM>, is directed to a method of roll-forming an aluminum alloy by processing an aluminum alloy plate to form a square bar, the method comprising pressing the plate so that deformation begins in a cross section thereof, and forming the square bar having at least one bent portion by completion of the deformation, and partially performing a heat treatment on the bent portion before forming the square bar.

<CIT> is directed to a process for roll-forming of high-strength cold-rolled sheet metal comprising feeding high-strength cold-rolled sheet metal continuously between rollers on a roll-forming production line, providing intense heat from a heat source locally prior to bending of the high-strength cold-rolled sheet metal, heating, with the intense heat, the cold-rolled sheet metal to a temperature within a two-phase sub-critical temperature region or above a critical temperature for the high-strength cold-rolled sheet metal, bending the high-strength cold-rolled sheet metal, and quenching the high-strength cold-rolled sheet metal rapidly after bending for the cold-rolled sheet metal to retain a high-temperature phase structure at room temperature.

<CIT> is directed to a roll forming device with beam tools, wherein the device has a feed arrangement that moves a workpiece in a material transport direction with a bending device for deforming the material as it passes through it and with at least one beam processing device directed towards the passing workpiece. Additionally, the roll forming device may be provided with a heating device directed towards the workpiece to heat it at least in some areas. <CIT> is directed to a shaping apparatus and process adapted to form a profile of variable section from a sheet metal, wherein the shaping apparatus comprises at least one shaping means including rollers, arranged opposite each other and movable with respect to the metal sheet, giving rise to the profile comprising at least one flank. The shaping apparatus further comprises heating means, arranged movable with respect to the metal sheet adapting to the corresponding variable sections of the metal sheet. The heating means locally heats a zone of the flank, said zone being a transition zone delimiting a change of cross section of the profile. <CIT> is directed to a method of and apparatus for the continuous manufacture of metal profile members of open or closed construction, especially steel profile members, from a continuous band or strip of metal.

<CIT> is directed to a precision hot roll forming process of high-strength semicircular and large-radio section steel, especially to the hot roll bending-stretching composite process forming method of a U-shaped boom of high-strength steel.

<CIT> is directed to a rolling process for the manufacture of profiles characterized therein that the rolling stock immediately prior feeding into the mating rolls is heated with a laser beam at places where sharp bends are to be produced and thus cracks may occur in the cold condition.

<CIT> is directed to a roll-forming method and device by electromagnetic induction heating between profile passes.

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 subject matter of the present invention is defined in the appended claims. The present disclosure provides systems and methods for forming high-strength metal substrates into complex shapes by roll-forming processes. To increase a formability of a high-strength metal substrate, the plasticity of the metal substrate is, at least temporarily, modified by heating the metal prior to or immediately prior to roll-forming to a first temperature.

The roll-forming process forms the metal after the metal to be formed, or a portion of it, cools below the first temperature or to ambient temperature. The roll-forming process may subject the metal to work hardening in the forming process such that after the forming, the formed metal product may continue to exhibit high-strength or, in some cases, even higher strength.

Due, at least in part, to the geometries involved in many roll-forming stand configurations, techniques for heating the metal substrate immediately prior to or between roll-forming operations may be limited. Additionally, it may be desirable to limit the extent of heating of the metal substrate to only those portions that are to be immediately formed in order to minimize any permanent property changes in other portions of the metal substrate that may occur from heating, though in some cases it may be desirable to heat an entirety of the metal substrate. Induction heating is described herein for heating local portions or an entirety of metal substrates prior to or between roll-forming operations, as magnetic sources useful for the heating operations can be sized and shaped to appropriately fit between roll-forming stands or at positions adjacent to a shaped elongated metal substrate and exhibit operational characteristics that provide for highly adjustable and controllable heat generation directly within the metal substrate. Laser heating is described herein for heating local portions or an entirety of metal substrates prior to or between roll-forming operations, as laser sources useful for the heating operations can be sized or positioned to appropriately allow heating between roll-forming stands or at positions adjacent to a shaped elongated metal substrate and exhibit operational characteristics that provide for highly adjustable and controllable heat generation at the metal substrate. The adjustability provided by induction heating and laser heating allows these techniques to be useful for the heating of various different alloys and metals to achieve exact temperatures needed to modify formability characteristics for the roll-forming process without sacrificing strength or other properties. In addition, the precisely controllable heating offered by induction heating or laser heating according to the present disclosure may also allow other properties of the metal to be modified during roll-forming, such as a temper condition or a corrosion resistance character.

In one aspect, methods of making metal products are disclosed. The method according to the invention comprises exposing an elongated metal substrate, which is a metal sheet, shate or plate, to a first time-varying magnetic field to heat at least a first portion of the elongated metal substrate by induction heating or exposing the elongated metal substrate to laser radiation. The heating occurs while the elongated metal substrate is moved along a rolling direction past a first magnetic field source generating the first time-varying magnetic field or past a first laser source generating laser radiation. The first time-varying magnetic field or laser radiation heats the first portion of the elongated metal substrate to or above a first temperature sufficient to increase formability or plasticity of at least the first portion of the elongated metal substrate, at least temporarily (e.g., while the substrate is heated to or above the first temperature). In some cases, the formability or plasticity of at least the first portion of the elongated metal substrate may be altered from adjacent portions of the elongated metal substrate. Various different metal alloys may exhibit or require different temperatures for modifying formability or plasticity. After heating, the elongated metal substrate is passed between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate after the at least the first portion of the elongated metal substrate cools from the first temperature. The first temperature is from <NUM> to <NUM>.

In various embodiments, the metal substrate comprises aluminum, an aluminum alloy, a steel alloy, stainless steel, magnesium, a magnesium alloy, copper, a copper alloy, titanium, or a titanium alloy. Optionally, the metal substrate comprises a 3xxx series aluminum alloy, a 5xxx series aluminum alloy, a 6xxx series aluminum alloy, or a 7xxx series aluminum alloy.

In some cases, the first temperature may be alloy dependent. In some examples, the first temperature may be from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM> when the elongated metal substrate comprises a 7xxx series alloy.

Forming or bending operations may be limited by a ratio of the bend radius (r) to the thickness (t) of the substrate, or r/t. Different metals and alloys may exhibit different r/t lower limits. In some cases, bending a metal substrate to an r/t smaller than an r/t limit may result in rupture or fracture of the substrate. In some embodiments, the first roll-forming stand bends the first portion of the elongated metal substrate to form a metal product having a feature with a ratio of bend radius to thickness (r/t) of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>.

Heating of the elongated metal substrate may result in other changes to the metal beyond changing, at least temporarily, a formability or plasticity of the metal substrate. For example, the first time-varying magnetic field or the laser radiation may heat at least the first portion of the elongated metal substrate to or above a second temperature for a sufficient time duration to modify a temper of the first portion of the elongated metal substrate. As an example, the first time-varying magnetic field or the laser radiation may heat at least the first portion of the elongated metal substrate to overage at least the first portion of the elongated metal substrate. Optionally, the first time-varying magnetic field or the laser radiation heats at least the first portion of the elongated metal substrate and modifies a corrosion resistance of at least the first portion of the elongated metal substrate. In some cases, the first time-varying magnetic field or the laser radiation heats an entirety of the elongated metal substrate and optionally modifies properties of the entirety of the elongated metal substrate.

Various operational parameters may be used to control the generation of heat in the elongated metal substrate. For example, a distance between the first magnetic field source and the elongated metal substrate may be adjusted to control a rate of heat generated in the elongated metal substrate by the induction heating. Optionally, the distance between the first magnetic field source and the elongated metal substrate ranges from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. A power of the laser radiation may control a rate of heat generated at the elongated metal substrate. A spot size or line width of the laser radiation may control a rate of heat generated at the elongated metal substrate. Example spot sizes may be from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM> from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. Depending, at least in part on the system geometries and the rolling speed of the elongated metal substrate, an exposure time of the elongated metal substrate to the first time-varying magnetic field or the laser radiation may be from <NUM> seconds to <NUM> seconds, such as from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, form <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> second, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, from <NUM> second to <NUM> seconds, form <NUM> second to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, from <NUM> seconds to <NUM> seconds, or from <NUM> seconds to <NUM> seconds.

In some embodiments, the magnetic field source comprises one or more permanent magnet coupled to a motor or rotor for rotating the permanent magnet. Optionally, a permanent magnet is a cylindrical magnet and the permanent magnet is rotated about a cylindrical axis. Optionally, a permanent magnet is a plurality of individual permanent magnets arranged about a rotor in a cylindrical or spaced configuration. Useful cylindrical magnets include those exhibiting diametric cylindrical magnets (e.g., where opposing magnetic poles are on opposite diametric sides of the magnet). Multipoled cylindrical magnets may also be useful. In some examples, multiple individual permanent magnets are arranged about an axis, such as where <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or more magnets are arranged about the axis, such as where poles of adjacent individual permanent magnets are positioned opposite to one another. Optionally, the motor has an adjustable speed for controlling the time-varying magnetic field. As an example, the motor may have a controllable rotation speed of from <NUM> revolution per minute to <NUM> revolutions per minute, such as from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolution per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolution per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, from <NUM> revolution per minute to <NUM> revolutions per minute, from <NUM> revolutions per minute to <NUM> revolutions per minute, or from <NUM> revolutions per minute to <NUM> revolutions per minute. Permanent magnets of different strengths may be used as the magnetic field source. For example, useful permanent magnets include those having a surface field strength of from <NUM> Gauss to <NUM> Gauss, such as from <NUM> Gauss to <NUM> gauss, from <NUM> Gauss to <NUM> Gauss, from <NUM> Gauss to <NUM> Gauss, from <NUM> gauss to <NUM> Gauss, or from <NUM> Gauss to <NUM> Gauss. Useful permanent magnets include those having a residual flux density of from <NUM> Gauss to <NUM> Gauss, such as from <NUM> Gauss to <NUM> Gauss or from <NUM> Gauss to <NUM> Gauss. In some embodiments, the magnetic field source comprises one or more electromagnetic coils and one or more power supplies electrically coupled to the electromagnetic coils. Optionally, the power supply has one or more of a variable output voltage, a variable output current, or a variable output frequency for controlling the time-varying magnetic field. Combinations of electromagnetic coils and rotating permanent magnets may be employed.

Multiple magnetic field sources and/or laser sources may be placed in a tandem or series arrangement, such as two, three, or more magnetic field sources and/or laser sources, allowing for exposure of the elongated metal substrate to multiple time-varying magnetic fields and laser radiation exposures to provide for more controllable heat generation at or within the elongated metal substrate and/or for a more controllable temperature profile, such as more controllable than could be achieved with only a single source. Such a configuration may allow a two, or more, step heating process for portions of the elongated metal substrate, for example. When multiple heat sources (e.g., magnetic field sources and/or laser sources) are used, sources may be positioned directly adjacent to one another on the same side of the elongated metal substrate, such that the elongated metal substrate encounters a first heat generation process (e.g., a first time-varying magnetic field generated by the first magnetic field source or first exposure to laser radiation generated by a first laser source) followed directly by a second heat generation process (e.g., a second time-varying magnetic field generated by second magnetic field source or a second exposure to laser radiation generated by a second laser source), for example. Optionally, multiple magnetic field sources and/or laser sources may be positioned on opposite sides of the elongated metal substrate, which may be useful, for example, for controlling spatial arrangements of components in a roll forming stand. In some cases, multiple magnetic field sources and/or laser sources may be positioned across a width of the elongated metal substrate, such as to provide for separate heating of separate lateral portions of the elongated metal substrate or to provide for a more complex heating/temperature profile across a width of the elongated metal substrate.

Multiple roll-forming operations can optionally be used with the methods of this aspect, with each roll-forming operation optionally preceded by one or more separate induction heating processes or laser heating processes for heating a portion of the elongated metal substrate for the roll-forming. In some embodiments, a method of this aspect comprises exposing the elongated metal substrate to a second or subsequent time-varying magnetic field or second or subsequent laser radiation to heat a second or subsequent portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along the rolling direction past a second or subsequent magnetic field source generating the second or subsequent time-varying magnetic field or a second or subsequent laser source generating the second or subsequent laser radiation. The second or subsequent time-varying magnetic field or second or subsequent laser radiation may heat the second or subsequent portion of the elongated metal substrate to or above a second or subsequent temperature sufficient to increase formability or plasticity of the second or subsequent portion of the elongated metal substrate after the first portion of the elongated metal substrate is bent by the at least two rollers of the first roll-forming stand.

Systems for making metal products are also described herein. The system for making a metal product according to the invention comprises a first magnetic field source positioned to expose an elongated metal substrate, which is a metal sheet, shate or plate, to a first time-varying magnetic field and heat at least a first portion of the elongated metal substrate by induction heating as the elongated metal substrate is moved along a rolling direction past the first magnetic field source, and a first roll-forming stand positioned to receive the elongated metal substrate after exposure to the first time-varying magnetic field. The first time-varying magnetic field heats at least the first portion of the elongated metal substrate to or above a first temperature sufficient to increase formability or plasticity of the first portion of the elongated metal substrate. In an alternative, the system for making a metal product according to the invention comprises a first laser source positioned to expose an elongated metal substrate, which is a metal sheet, shate or plate, to a first laser radiation to heat at least a first portion of the elongated metal substrate by laser heating as the elongated metal substrate is moved along a rolling direction past the first laser source, and a first roll-forming stand positioned to receive the elongated metal substrate after exposure to the first laser radiation. The first laser radiation heats at least the first portion of the elongated metal substrate to or above a first temperature sufficient to increase formability or plasticity of the first portion of the elongated metal substrate. The roll-forming stand comprises at least two rollers arranged to receive the elongated metal substrate and bend the first portion of the elongated metal substrate while at least the first portion of the elongated metal substrate is cooled below the first temperature or to ambient temperature. The systems described may be used to perform the methods described herein. Formed metal products are also provided herein. For example, metal products may be formed using any of the methods described herein or any of the systems described herein. In some embodiments, a formed metal product may comprise an automotive structural product.

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

Described herein are systems and methods for performing roll-forming on metal substrates and formed metal products. The metal substrates are subjected to induction heating during the roll-forming process by exposure to time-varying magnetic fields, such as by exposure to a rotating permanent magnet. Heating of the metal substrates allow improved formability or plasticity of the substrate in order to reduce or eliminate damage to the substrate during roll-forming to low bending radius to thickness ratios (r/t). Heating of the metal substrates can also function to temper the substrates, such as to overage the substrates, and form high-strength end products.

High-strength aluminum alloys (e.g., 7xxx series aluminum alloys) can be difficult to form, such as by stamping, drawing, roll-forming, etc. For example, forming such wrought aluminum alloys to a bending radius to thickness ratio (r/t) less than <NUM> can typically result in fracture or damage to the alloy structure. In many cases, formed metal products of high-strength aluminum alloys may not be suitable for some end products because of the low ability of the high-strength aluminum alloy to be formed into the complex shapes needed for the end products. In some cases, aluminum alloys may be extruded into parts having cross sections with low r/t features since the r/t features are the result of an extrusion process rather than a forming process. Accordingly, use of wrought aluminum of high-strength alloys may not generally be suitable for some applications. The present invention, however, overcomes these and other limitations by at least temporarily increasing the formability of wrought aluminum substrates, allowing smaller r/t features to be achieved during a forming process without resulting in damage to the substrate structure, while still retaining high strength in the formed end product.

Wrought end products having dimensions and cross-sections comparable to extruded end products can be formed, for example, by a roll-forming process according to the present disclosure. Roll-forming, as described herein, refers to a process by which an elongated metal substrate is formed by passing the substrate between two rollers to plastically bend or deform the elongated metal substrate. In some cases, multiple rollers can be used for the roll-forming process. In some embodiments, multiple roll-forming stands, each corresponding to a single roll-forming stage, to form the elongated metal substrate into complex cross-sectional shapes. Cross-sectional shapes having low bending radius features are useful, for example, for increasing strength of the end products in a direction perpendicular to the cross-section, making such end products more suitable as structural elements.

As examples, automotive body components, such as pillars, rocker panels, and bumpers may be formed of metal substrates, such as high-strength wrought aluminum substrates, subjected to roll-forming according to the present invention.

The methods and systems described herein for roll-forming wrought metal substrates employ techniques for heating a substrate to improve the formability or plasticity of the substrates to permit bending of portions of the substrates by roll-forming stands. Induction heating is utilized for the heating, as the technique allows precise control over where and what temperature portions of a substrate are heated to, limiting exposure of an entirety of a substrate to elevated temperatures. As an example, only a portion of a substrate that is subjected to roll-forming is heated to increase the formability or plasticity of that portion, while other portions of the substrate are either not heated or only heated to lower temperatures (e.g., at which formability or plasticity does not significantly increase). Since many metals exhibit high thermal conductivities, it can be advantageous to apply heat only to portions of the metal substrate that are to undergo bending by a roll-forming stand in order to minimize the temperature that other portions of the metal may obtain by conduction within the substrate. Heat transfer from the heated substrate to the rollers of the roll-forming stand can also serve to minimize the conduction of heat from the heated portions to other portions of the substrate for which exposure to elevated temperatures is not desired. As another example, an entirety of a substrate that is subjected to roll-forming is heated to increase the formability or plasticity of the entire substrate, such as prior to entering a series of roll-forming stands. Optionally, additional induction heating systems may be positioned between roll-forming stands, such as to maintain a temperature of the substrate. Such a configuration may be useful for avoiding having to heat the entire roll-forming system or for having to have the roll-forming system placed in a heated environment, while still allowing the entirety of the substrate to be at an elevated temperature where formability or plasticity is at a desirable state.

Induction heating is advantageously employed by the techniques, methods, and systems described herein, as the heat is generated directly within the metal substrate, rather than transferred to the metal substrate by convection or conduction. Induction can be achieved by exposing the metal substrate to a time-varying magnetic field, and may also be referred to herein as to electromagnetic induction and/or magnetic induction. Various magnetic field sources for generating time-varying magnetic fields are contemplated, including rotating permanent magnets or electromagnetic coils energized by alternating currents. Different advantages may arise through use of different magnetic field sources. For example, use of rotating permanent magnets does not require a current source, but does require a motor for rotating the permanent magnets. On the other hand, an electromagnetic coil does not require any physically moving parts but can employ complex coil geometries and makes use of a power source for providing alternating current. <CIT>, and published under publication number <CIT> describes additional details regarding use of rotating magnets for heat generation by induction.

In this description, reference is made to alloys identified by AA numbers and other related designations, such as "series" or "7xxx. " For an understanding of the 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.

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 about <NUM>, greater than about <NUM>, greater than about <NUM>, greater than about <NUM>, greater than about <NUM>, greater than about <NUM>, greater than about <NUM>, greater than about <NUM>, or greater than about <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 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>.

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 about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, or less than about <NUM> (e.g., about <NUM>).

Reference may be made in this application to alloy temper or condition. For an understanding of the alloy temper descriptions most commonly used, see "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems. " An F condition or temper refers to an aluminum alloy as fabricated. An O condition or temper refers to an aluminum alloy after annealing. An Hxx condition or temper, also referred to herein as an H temper, refers to a non-heat treatable aluminum alloy after cold rolling with or without thermal treatment (e.g., annealing). Suitable H tempers include HX1, HX2, HX3 HX4, HX5, HX6, HX7, HX8, or HX9 tempers. A T1 condition or temper refers to an aluminum alloy cooled from hot working and naturally aged (e.g., at room temperature). A T2 condition or temper refers to an aluminum alloy cooled from hot working, cold worked and naturally aged. A T3 condition or temper refers to an aluminum alloy solution heat treated, cold worked, and naturally aged. A T4 condition or temper refers to an aluminum alloy solution heat treated and naturally aged. A T5 condition or temper refers to an aluminum alloy cooled from hot working and artificially aged (at elevated temperatures). A T6 condition or temper refers to an aluminum alloy solution heat treated and artificially aged. A T7 condition or temper refers to an aluminum alloy solution heat treated and artificially overaged. A T8x condition or temper refers to an aluminum alloy solution heat treated, cold worked, and artificially aged. A T9 condition or temper refers to an aluminum alloy solution heat treated, artificially aged, and cold worked. A W condition or temper refers to an aluminum alloy after solution heat treatment.

As used herein, terms such as "cast metal product," "cast product," "cast aluminum alloy product," and the like are interchangeable and refer to a product produced by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting (including, for example, by use of a twin belt caster, a twin roll caster, a block caster, or any other continuous caster), electromagnetic casting, hot top casting, or any other casting method. Cast metal products can be transformed into wrought metal products through one or more working processes, such as one or more hot-rolling or cold-rolling processes, a hammering, or other process in which the grain structure of the cast product is physically modified.

As used herein, the term "wrought metal" is used to provide a distinction with other metal products that are simply cast or extruded into end products without a working process (e.g., rolling). Example wrought metal products include those formed by working a cast product, such as an ingot, into a thinner and longer product through one or more hot rolling and/or cold rolling steps. Example wrought metal products include metal substrates, such as elongated metal substrate, metal plates, metal shates, and metal sheets.

As used herein, the meaning of "room temperature" can include a temperature of from about <NUM> to about <NUM>, for example 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>, about <NUM>, or about <NUM>. As used herein, the meaning of "ambient conditions" can include temperatures of about room temperature, relative humidity of from about <NUM>% to about <NUM>%, and barometric pressure of from about <NUM> millibar (mbar) to about <NUM> mbar. For example, relative humidity can be 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>%, 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>%, 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>%, 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>%, 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>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, about <NUM>%, or anywhere in between. For example, barometric pressure can be about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, about <NUM> mbar, or anywhere in between.

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>. Unless stated otherwise, the expression "up to" when referring to the compositional amount of an element means that element is optional and includes a zero percent composition of that particular element.

The metal substrates described and utilized herein can be produced by first casting a molten metal using any suitable casting method. As a few non-limiting examples, the casting process can include a Direct Chill (DC) casting process or a Continuous Casting (CC) process. The continuous casting system can include a pair of moving opposed casting surfaces (e.g., moving opposed belts, rolls or blocks), a casting cavity between the pair of moving opposed casting surfaces, and a molten metal injector. The molten metal injector can have an end opening from which molten metal can exit the molten metal injector and be injected into the casting cavity.

Example metal substrates may comprise steel, aluminum alloys, magnesium and magnesium alloys, titanium and titanium alloys. Useful aluminum alloys include heat-treatable alloys and non-heat-treatable alloys. Example aluminum alloys include, but are not limited to, 3xxx series aluminum alloys, 5xxx series aluminum alloys, and 7xxx series aluminum alloys. In some cases, 4xxx series aluminum alloys or 6xxx series aluminum alloys may be useful aluminum alloys.

A cast product can then be processed by any suitable means to work the cast product into a wrought metal product. For example, the processing steps can be used to prepare plates, shates, or sheets. Such processing steps include, but are not limited to, homogenization, hot rolling, cold rolling, solution heat treatment, and an optional pre-aging step.

Metal substrates, such as metal sheets, shates, and plates, may be used to make metal products through one or more roll-forming processes. Roll-forming refers to a process in which a metal substrate, such as an elongated metal substrate, is subjected to a bending operation where two or more rollers force the elongated metal substrate to undergo plastic deformation along a longitudinal or rolling axis of the substrate as it moves between the rollers. Elongated metal substrates are typically used, as roll-forming can be a continuous or semi-continuous process in which long lengths of metal substrates are processed to bend the metal substrate the same way along a longitudinal (i.e., the longest) axis of the substrate. As used herein, an elongated metal substrate refers to a metal substrate having a length that is greater than a width. In some cases, a length of an elongated metal substrate may be <NUM>-<NUM> times (or more) the width of the substrate. For example, a metal coil may be hundreds of meters long, but only a few or a fraction of a meter wide and bent, by roll-forming, at a point along its width but entirely along its length by roll-forming. In some cases, an elongated metal substrate may be referred to as a metal strip. Metal substrates subjected to roll-forming may be referred to herein as roll-formed products or roll-formed metal products.

Metal sheets are a primary subject of roll-forming, since they exhibit lower thicknesses and can typically withstand bending to lower bending radii than metal shates and plates, which have an overall greater thickness. In some cases, however, metal shates and metal plates can be subjected to roll-forming, particularly when formed into products with larger bending radius features. Bending operations can be characterized by a ratio of the bending radius to the thickness (r/t). Bending can impart both compressive and tensile stresses and strains to a metal substrate and, depending on the strength and composition of the metal, the bent metal substrate can fracture, tear, or otherwise rupture during the bending process if bent to form a small r/t feature. Softer or more ductile metals can typically withstand bending to smaller r/t features than stronger or less formable metals.

The present invention, however, allows for metal substrates of higher strength to be roll-formed into smaller r/t features than the intrinsic strength and formability character of the metal alone may dictate. For example, 7xxx series aluminum in a T4 or T6 temper may be difficult to form into a product having low r/t features, but this obstacle is overcome by the presently disclosed systems and methods.

<FIG> provides a schematic illustration of a system <NUM> for making metal products. Elongated metal substrate <NUM> is shown moving along direction <NUM> through system <NUM>. System <NUM> includes a plurality of roll-forming stands <NUM>, a plurality of magnetic field sources <NUM>, and a plurality of laser sources <NUM>. A bent metal product <NUM> exits the system <NUM> after all roll-forming stands <NUM>. Although elongated metal substrate <NUM> is shown as originating from a coil, other configurations may include processing elongated metal substrate as a metal blank or a metal strip.

Each roll-forming stand <NUM> includes two or more rollers driven along independent rotation axes in a configuration to receive and pass elongated metal substrate <NUM> between the rollers. The rollers may include roller surfaces with surface profiles relatively oriented with respect to each other for bending, in a direction different from direction <NUM>, the elongated metal substrate <NUM> as it passes between the rollers along direction <NUM>. Optionally, each roll-forming stand <NUM> includes a top roller having a top rotation axis and a top roller surface and a bottom roller having a bottom rotation axis and a bottom roller surface. Optionally, other roller configurations may be included in a roll-forming stand <NUM>, such as a forming roller oriented with respect to a top roller or a bottom roller with a rotation axis and surface profile positioned relative to other rollers to bend the elongated metal substrate as it passes through the roll-forming stand <NUM>. Each roll-forming stand <NUM> may be different from other roll-forming stands <NUM>, such as to allow for different bend operations to occur at each roll-forming stand <NUM>.

Each magnetic field source <NUM> generates a time-varying magnetic field to heat a portion of elongated metal substrate <NUM> via induction heating. Each laser source <NUM> generates laser radiation and exposes and heats a portion of elongated metal substrate <NUM> via laser heating. Depending on the configuration, different portions of elongated metal substrate <NUM> may be heated by the different magnetic field sources <NUM> and/or laser sources <NUM>. The magnetic field sources <NUM> and/or laser sources <NUM> are positioned before and optionally after roll-forming stands <NUM>. In some cases, magnetic field sources <NUM> and/or laser sources <NUM> may not be positioned before or after every roll-forming stand <NUM>. The magnetic field sources <NUM> and/or laser sources <NUM> may be independently positioned on a top side or bottom side of the elongated metal substrate <NUM>. A position of the magnetic field sources <NUM> and/or laser sources <NUM> may, at least in part, be governed by the particular bend operation achieved by the roll-forming stands <NUM>. For example, an interior bend surface of elongated metal substrate <NUM> may face an magnetic field source <NUM> and/or laser source <NUM> positioned before and/or after a roll-forming stand <NUM>. As another example, in some cases, an exterior bend surface of elongated metal substrate <NUM> may face an magnetic field source <NUM> and/or laser source <NUM> positioned before and/or after a roll-forming stand <NUM>. Although a combination of magnetic field sources <NUM> and laser source <NUM> are shown in system <NUM>, magnetic field sources <NUM> and laser source <NUM> may be used alone or in any combination in any desirable number. For example, system <NUM> may comprise one or multiple magnetic field sources <NUM> and no laser sources <NUM>. As another example, system <NUM> may comprise one or multiple laser sources <NUM> and no magnetic field sources <NUM>.

The heating increases a temperature of a portion of elongated metal substrate <NUM> to or above a temperature sufficient to, temporarily or permanently, increase formability or plasticity of the portion of the elongated metal substrate. In some cases, the heating may be of a sufficient time duration to modify a temper of the portion of the elongated metal substrate <NUM>. Optionally, the heating may overage the portion of the elongated metal substrate <NUM>. Optionally, the heating may modify (e.g., increase) a corrosion resistance of the portion of the elongated metal substrate <NUM>. The temperature of the elongated metal substrate <NUM> is raised to or above the temperature sufficient to, at least temporarily, increase formability or plasticity of the portion of the elongated metal substrate for any suitable time duration, such as between <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, <NUM> seconds and <NUM> seconds, or <NUM> seconds and <NUM> seconds.

<FIG> provide schematic illustrations showing a roll-forming process performed by a roll-forming system <NUM> including a single roll-forming stand. <FIG> provides a side view of roll-forming system <NUM>, <FIG> provides a perspective view of roll-forming system <NUM>, and <FIG> provides a top view of roll-forming system <NUM>. An elongated metal substrate <NUM> passes along direction <NUM> (illustrated as parallel to the y-axis) between rollers <NUM> of a roll-forming stand to form a bent metal product <NUM>. A width of elongated metal substrate <NUM> is illustrated as parallel to the x-axis, with a thickness of elongated metal substrate <NUM> illustrated as parallel to the z-axis. Two magnetic field sources <NUM> are positioned to expose elongated metal substrate <NUM> to time-varying magnetic fields to heat portion <NUM> of elongated metal substrate <NUM> by induction heating.

In <FIG>, magnetic field sources <NUM> are illustrated as rotating permanent magnets coupled to variable speed motors, in which distances (e.g., parallel to the z-axis) between the magnetic field sources <NUM> and elongated metal substrate <NUM> can be independently adjusted. An adjustable distance between the magnetic field sources <NUM> and the elongated metal substrate <NUM> may be useful for controlling a rate of heat generation in the portion <NUM> of elongated metal substrate <NUM> by induction heating.

In <FIG>, magnetic field sources <NUM> are also illustrated as a rotating permanent magnet, but with a different geometry than that shown in <FIG>, such as where the rotating permanent magnets are elongated cylindrical magnet (e.g., diametrically magnetized) with a diameter less than the width of elongated metal substrate <NUM>.

In <FIG>, magnetic field sources <NUM> are illustrated as electromagnetic coils. A power supply (not illustrated) may be electrically coupled to the electromagnetic coils. The power supply may have adjustable or variable output voltages, adjustable or variable output currents, and/or adjustable or variable output frequencies for controlling the time-varying magnetic fields and the rate of heat generation in the portion <NUM> of elongated metal substrate <NUM>.

Although <FIG> show magnetic field sources <NUM>, laser sources may be substituted for any one or more or all of the magnetic field sources <NUM>, without limitation.

<FIG> shows an example temperature distribution of elongated metal substrate along the width (x-axis) achieved by heating using a magnetic field source providing a time-varying magnetic field or laser source providing laser radiation. The y-axis position may correspond to a point immediately following the magnetic field source or laser source or may correspond to a point at which bending by a roll-forming stand occurs, for example. It will be appreciated that the temperature distribution shown in <FIG> is merely an example and that other temperature distributions may be used. Various different spatial temperature profiles may be achieved and used for purposes of increasing formability, modifying temper, modifying corrosion resistance, etc. In addition, units are not depicted in <FIG> so as to not overly limit or complicate the discussion of temperature within the elongated metal substrate. At the furthest points away from heated portion <NUM>, elongated metal substrate has the minimum temperature, which may correspond to ambient conditions or room temperature or another temperature. The temperature at the edges (x positions equal to <NUM> and <NUM>) of elongated metal substrate may be higher than ambient conditions, due to heat conduction from heated portion <NUM> towards the edges of the elongated metal substrate. Within heated portion <NUM>, the temperature may be at or above a suitable temperature <NUM> for achieving a target formability or plasticity in the heated portion <NUM> of the elongated metal substrate. In some embodiments, only heated portion <NUM> is heated above the ambient or minimum temperature, with a relatively uniform temperature across heated portion <NUM> at a target temperature suitable for a desired formability, a desired plasticity, a desired temper modification, a desired corrosion resistance property modification, etc..

<FIG> shows an example temperature distribution of elongated metal substrate along y-axis achieved by heating using a magnetic field source providing a time-varying magnetic field or laser source providing laser radiation. The x-axis position may correspond to a point within region <NUM> (e.g., a center point within heated portion <NUM>). It will be appreciated that the temperature distribution shown in <FIG> is merely an example and that other temperature distributions may be used. Various different spatial temperature profiles may be achieved and used for purposes of increasing formability, modifying temper, modifying corrosion resistance, etc. In addition, units are not depicted in <FIG> so as to not overly limit or complicate the discussion of temperature within the elongated metal substrate. The elongated metal substrate may be exposed to the time-varying magnetic field from the magnetic field source or laser radiation from the laser source at region <NUM>. The temperature prior to this may correspond to ambient conditions or room temperature but may alternatively be greater than that due to residual heat left in elongated metal substrate from a prior process (e.g., roll-forming, annealing, electromagnetic heating, etc.). Following region <NUM>, the temperature may decrease by conductive or convective heat loss. Roll-forming takes place immediately following region <NUM> or takes place at a greater y-position. Optionally, roll-forming takes place before the temperature falls below a target temperature suitable for achieving a desired formability or plasticity. Optionally, roll-forming takes place after the temperature falls back to room temperature or ambient temperature. A length of region <NUM> may be dictated by a travel speed of the elongated metal substrate and a length or width of the magnetic field source or laser radiation generated by the laser source. Stated another way, an exposure time of the elongated metal substrate may be dictated by a travel speed of the elongated metal substrate and a length or width of the magnetic field source or laser radiation generated by the laser source. In some cases, multiple magnetic field sources or laser sources may be used to increase a length of region <NUM>, which may be useful for achieving a target time duration for subjecting the portion of the elongated metal substrate to increased temperatures.

Different configurations may be utilized to achieve heating for different elongated metal substrates, depending on composition, temper, bend performance (r/t), etc. For example, for elongated metal substrates comprising an aluminum alloy, an alloy composition may dictate or influence the target temperature for the heated portion. In some cases, a thickness of the elongated metal substrate may dictate or influence target temperature for the heated portion.

As an example, for a 3xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. is from <NUM> to <NUM>. As another example, for a 4xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. is from <NUM> to <NUM>. As another example, for a 5xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. is from <NUM> to <NUM>. As another example, for a 6xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. is from <NUM> to <NUM>. As another example, for a 7xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. is from <NUM> to <NUM>.

To achieve such temperature conditions using a rotating permanent magnet, various operational configurations may be selected that, again, may depend on metal substrate composition, initial and/or desired final temper, bend performance (r/t), initial and/or desired final corrosion resistance condition, etc. As an example, a rotating permanent magnet may have a diameter of between <NUM> and <NUM>. As another example, a rotating permanent magnet may have a length or thickness of between <NUM> and <NUM>. As another example, a rotating permanent magnet may have a surface field strength of between <NUM> Gauss and <NUM> Gauss. As another example, a rotating permanent magnet may have a residual flux density of between <NUM> Gauss and <NUM> Gauss. As another example, a rotating permanent magnet may be rotated at a rate of between <NUM> revolutions per minute and <NUM> revolutions per minute.

In the case of an electromagnetic coil used to heat the elongated metal substrate by induction heating, coil size (diameter, number of turns, etc.) and electrical operational characteristics (current, voltage, frequency) may be selected to achieve a target temperature condition. These characteristics may, again, depend on metal substrate composition, initial and/or desired final temper, bend performance (r/t), initial and/or desired final corrosion resistance condition, etc. As an example, an electromagnetic coil may have a diameter of between <NUM> and <NUM>. As an example, an electromagnetic coil may have a number of turns per inch of between <NUM> and <NUM>. As another example, an electromagnetic coil may be energized using an AC voltage of between <NUM> V and <NUM> V. As another example, an electromagnetic coil may be energized using an AC voltage having a frequency of between <NUM> and <NUM>. As another example, an electromagnetic coil may be energized using an AC current of between <NUM> A and <NUM> A.

In the case of a laser source generating laser radiation to heat the elongated metal substrate by laser heating, one or more of the laser type, fluence, output power, pulse rate, or spot size may be selected to achieve a target temperature condition. These characteristics may, again, depend on metal substrate composition, initial and/or desired final temper, bend performance (r/t), initial and/or desired final corrosion resistance condition, etc. As examples, any suitable type of laser may be used to generate the laser radiation, such as, but not limited to, diode lasers, fiber lasers, CO<NUM> lasers, YAG lasers, excimer laser, dye lasers, ion lasers, or the like. Optionally, the laser radiation may have a spot size (e.g., at the elongated metal substrate) of from <NUM> to <NUM>. In some examples a homogenizing or dispersing optic may be used to spread the laser radiation along a line or rectangular focus area, optionally spread across or beyond a full width the elongated metal substrate. Optionally, the laser radiation may have an output power of from <NUM> W to <NUM> kW. Optionally, the laser radiation may be delivered to the elongated metal structure using one or more optical elements, such as mirrors, lenses, prisms, waveguides, optical fibers, gratings, filters, beamsplitters, polarizers, or the like.

By way of non-limiting examples, exemplary AA3xxx series alloys for use in the methods described herein can include AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203, AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A, AA3105, AA3105A, AA3105B, AA3007, AA3107, AA3207, AA3207A, AA3307, AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014, AA3015, AA3016, AA3017, AA3019, AA3020, AA3021, AA3025, AA3026, AA3030, AA3130, or AA3065.

Non-limiting exemplary AA4xxx series alloys for use in the methods described herein can include AA4004, AA4104, AA4006, AA4007, AA4008, AA4009, AA4010, AA4013, AA4014, AA4015, AA4015A, AA4115, AA4016, AA4017, AA4018, AA4019, AA4020, AA4021, AA4026, AA4032, AA4043, AA4043A, AA4143, AA4343, AA4643, AA4943, AA4044, AA4045, AA4145, AA4145A, AA4046, AA4047, AA4047A, or AA4147.

Non-limiting exemplary AA5xxx series alloys for use in the methods described herein can include AA5182, AA5183, AA5005, AA5005A, AA5205, AA5305, AA5505, AA5605, AA5006, AA5106, AA5010, AA5110, AA5110A, AA5210, AA5310, AA5016, AA5017, AA5018, AA5018A, AA5019, AA5019A, AA5119, AA5119A, AA5021, AA5022, AA5023, AA5024, AA5026, AA5027, AA5028, AA5040, AA5140, AA5041, AA5042, AA5043, AA5049, AA5149, AA5249, AA5349, AA5449, AA5449A, AA5050, AA5050A, AA5050C, AA5150, AA5051, AA5051A, AA5151, AA5251, AA5251A, AA5351, AA5451, AA5052, AA5252, AA5352, AA5154, AA5154A, AA5154B, AA5154C, AA5254, AA5354, AA5454, AA5554, AA5654, AA5654A, AA5754, AA5854, AA5954, AA5056, AA5356, AA5356A, AA5456, AA5456A, AA5456B, AA5556, AA5556A, AA5556B, AA5556C, AA5257, AA5457, AA5557, AA5657, AA5058, AA5059, AA5070, AA5180, AA5180A, AA5082, AA5182, AA5083, AA5183, AA5183A, AA5283, AA5283A, AA5283B, AA5383, AA5483, AA5086, AA5186, AA5087, AA5187, or AA5088.

Non-limiting exemplary AA6xxx series alloys for use in the methods described herein can include AA6101, AA6101A, AA6101B, AA6201, AA6201A, AA6401, AA6501, AA6002, AA6003, AA6103, AA6005, AA6005A, AA6005B, AA6005C, AA6105, AA6205, AA6305, AA6006, AA6106, AA6206, AA6306, AA6008, AA6009, AA6010, AA6110, AA6110A, AA6011, AA6111, AA6012, AA6012A, AA6013, AA6113, AA6014, AA6015, AA6016, AA6016A, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022, AA6023, AA6024, AA6025, AA6026, AA6027, AA6028, AA6031, AA6032, AA6033, AA6040, AA6041, AA6042, AA6043, AA6151, AA6351, AA6351A, AA6451, AA6951, AA6053, AA6055, AA6056, AA6156, AA6060, AA6160, AA6260, AA6360, AA6460, AA6460B, AA6560, AA6660, AA6061, AA6061A, AA6261, AA6361, AA6162, AA6262, AA6262A, AA6063, AA6063A, AA6463, AA6463A, AA6763, AA6963, AA6064, AA6064A, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6181, AA6181A, AA6082, AA6082A, AA6182, AA6091, or AA6092.

Non-limiting exemplary AA7xxx series alloys for use in the methods described herein can include AA7011, AA7019, AA7020, AA7021, AA7039, AA7072, AA7075, AA7085, AA7108, AA7108A, AA7015, AA7017, AA7018, AA7019A, AA7024, AA7025, AA7028, AA7030, AA7031, AA7033, AA7035, AA7035A, AA7046, AA7046A, AA7003, AA7004, AA7005, AA7009, AA7010, AA7011, AA7012, AA7014, AA7016, AA7116, AA7122, AA7023, AA7026, AA7029, AA7129, AA7229, AA7032, AA7033, AA7034, AA7036, AA7136, AA7037, AA7040, AA7140, AA7041, AA7049, AA7049A, AA7149, AA7204, AA7249, AA7349, AA7449, AA7050, AA7050A, AA7150, AA7250, AA7055, AA7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7175, AA7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7185, AA7090, AA7093, AA7095, or AA7099.

<FIG> provides a schematic illustration showing a roll-forming system <NUM> including three roll-forming stands. As illustrated in <FIG>, an elongated metal substrate <NUM> passes between rollers <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> (collectively, rollers <NUM>) of the roll-forming stands. At each roll-forming stand, elongated metal substrate is roll-formed into a bent configuration. Magnetic field sources <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> (collectively, magnetic field sources <NUM>) are positioned adjacent to elongated metal substrate <NUM> to expose elongated metal substrate <NUM> to time-varying magnetic fields to heat portions <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> (collectively, portions <NUM>) of elongated metal substrate <NUM> by induction heating.

Although magnetic field sources <NUM> are shown as positioned above elongated metal substrate <NUM>, configurations are contemplated where some or all magnetic field sources <NUM> are positioned below elongated metal substrate <NUM>. Magnetic field sources <NUM> are illustrated as rotating permanent cylindrical magnets, but other configurations are possible. Each cylindrical magnet may be coupled to a variable speed motor (not illustrated in <FIG>). An adjustable distance between the magnetic field sources <NUM> and the elongated metal substrate <NUM> may be useful for controlling a rate of heat generation in the portions <NUM> of elongated metal substrate <NUM> by induction heating.

Different positions along the width dimension of elongated metal substrate <NUM> for each of the magnetic field sources <NUM> and portions <NUM> are illustrated in <FIG>. The positions of magnetic field sources <NUM> and portions <NUM> are shown as overlapping with the portion of the elongated metal substrate <NUM> to be bent by each roll-forming stand. For example, the first roll-forming stand forms first bends <NUM> in elongated metal substrate <NUM>, which are positioned along the width direction in line with magnetic field sources <NUM>-<NUM> and portions <NUM>-<NUM>. The second roll-forming forming stand forms second bends <NUM> in elongated metal substrate <NUM>, which are positioned along the width direction in line with magnetic field sources <NUM>-<NUM> and portions <NUM>-<NUM>. The third bends <NUM> in elongated metal substrate <NUM> are shown as overlapping with first bends <NUM>, but have an opposite bend direction. Third bends <NUM> are positioned along the width direction in line with magnetic field sources <NUM>-<NUM> and portions <NUM>-<NUM>.

In <FIG>, one additional magnetic field source <NUM> is illustrated after the third roll-forming stand including rollers <NUM>-<NUM>. Magnetic field source <NUM> is oriented to heat portion <NUM> of elongated metal substrate <NUM>, which extends substantially entirely along the width. Such a configuration may be useful for heating the entirety of elongated metal substrate <NUM> as it travels past magnetic field source <NUM>. For example, such a configuration may be useful for heating elongated metal substrate <NUM> to achieve or modify an overall temper condition or to achieve or modify an overall corrosion resistance character.

Although <FIG> shows magnetic field sources <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>, laser sources may be substituted for any one or more or all of the magnetic field sources <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>, without limitation.

<FIG> provides a schematic illustration of another system <NUM> for making metal products where preheating of an elongated metal substrate <NUM> using an induction system <NUM> is used. Elongated metal substrate <NUM> is shown moving along direction <NUM> through system <NUM>. Induction system <NUM> can comprise a series of permanent magnet rotors <NUM> arranged adjacent to elongated metal substrate <NUM> as it passes through induction system <NUM>. Induction system <NUM> can include rollers <NUM> to allow for drawing the elongated metal substrate <NUM> along different directions, so as to allow more linear length and space for interaction with permanent magnetic rotors <NUM> while reducing the footprint of induction system <NUM>. System <NUM> also includes a plurality of roll-forming stands <NUM> and optionally includes additional magnetic field sources <NUM>. A bent metal product <NUM> exits the system <NUM> after all roll-forming stands <NUM>. Although elongated metal substrate <NUM> is shown as originating from a coil, other configurations may include processing elongated metal substrate as a metal blank or a metal strip.

Each roll-forming stand <NUM> may include two or more rollers driven along independent rotation axes in a configuration to receive and pass elongated metal substrate <NUM> between the rollers. With induction system <NUM> provided upstream of roll-forming stands <NUM>, a temperature of elongated metal substrate <NUM> may be raised to a temperature suitable to increase the formability of the elongated metal substrate <NUM> prior to any roll forming occurring by roll-forming stand <NUM>. In this way, elongated metal substrate <NUM> can be in a fully preheated condition prior to entering the first roll-forming stand <NUM>.

Each magnetic field source <NUM> may be used to add additional heat to elongated metal substrate <NUM> via induction heating. Although magnetic field sources <NUM> are depicted as electromagnetic coils in <FIG>, in some cases one or more of the magnetic field sources <NUM> may comprise rotating permanent magnets, similar to permanent magnetic rotors <NUM>. In some cases, the magnetic field sources <NUM> can add heat along a full width of the elongated metal substrate <NUM> as it moves past magnetic field sources <NUM>, for example to maintain a temperature of the elongated metal substrate <NUM> after preheating by induction system <NUM> due to heat losses at roll-forming stands <NUM> or due to heat losses to the environment. In some cases, the magnetic field sources <NUM> can increase a temperature of the elongated metal substrate to further increase formability character, such as prior to particularly severe deformations that may occur at a roll-forming stand <NUM>. In some cases, heat added by a magnetic field source <NUM> may be at a local position along the width of the elongated metal substrate <NUM>. As shown, the magnetic field sources <NUM> may be positioned before and/or after roll-forming stands <NUM>. In some cases, magnetic field sources <NUM> may not be positioned before or after every roll-forming stand <NUM>. The magnetic field sources <NUM> may be independently positioned on a top side or bottom side of the elongated metal substrate <NUM>.

<FIG> provides a schematic illustration showing a roll-forming system <NUM> including three roll-forming stands, similar to roll-forming system <NUM> shown in <FIG>. As illustrated in <FIG>, an elongated metal substrate <NUM> passes between a pair of permanent magnetic rotors <NUM> to preheat elongated metal substrate <NUM> across its full width. Although a single pair of permanent magnetic rotors <NUM> is shown in <FIG>, any suitable number of permanent magnetic rotors may be used, with the configuration shown in <FIG> simply representing one pair of permanent magnetic rotors <NUM> or a portion of an induction system comprising multiple permanent magnetic rotors. Examples of an induction system featuring multiple permanent magnetic rotors are described in <CIT>.

After preheating by the pair of permanent magnetic rotors <NUM>, elongated metal substrate <NUM> passes through rollers <NUM> of different roll-forming stands. At each roll-forming stand, elongated metal substrate <NUM> is roll-formed into different bent configurations.

Magnetic field sources <NUM>, depicted as electromagnetic coils, are shown positioned adjacent to elongated metal substrate <NUM> at various points to expose elongated metal substrate <NUM> to time-varying magnetic fields to further add heat to elongated metal substrate <NUM> by induction heating. Although magnetic field sources <NUM> are shown as positioned above elongated metal substrate <NUM>, configurations are contemplated where some or all magnetic field sources <NUM> are positioned below elongated metal substrate <NUM>. Although <FIG> shows magnetic field sources <NUM> and permanent magnetic rotors <NUM>, laser sources may be substituted for any one or more or all of the magnetic field sources <NUM> and permanent magnetic rotors <NUM>, without limitation.

The aluminum alloy products described herein can be used in automotive applications and other transportation applications, including aircraft and railway applications. 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.

Aspects of the invention may be further understood by reference to the following non-limiting examples.

Samples of a <NUM> aluminum alloy sheet with a thickness of <NUM> were obtained in a T6 temper condition (e.g., by tempering at <NUM> for <NUM> hours). The samples were subjected to rapid heating to various temperatures under conditions similar to those achieved by induction heating and laser heating, where the temperature was rapidly raised to a target temperature using a fluidized sand bath. Temperatures of <NUM>, <NUM>, <NUM>, and <NUM> were used. As a control, some samples were not subjected to heating.

To evaluate the bending performance of the samples under roll-forming conditions, some of the sample samples were subjected to a <NUM> point bend test after the rapid heating process. Force was logged as a function of vertical displacement, and the test was stopped when the force-displacement curve showed a significant drop. The outer bending angle (α) was measured manually afterwards. <FIG> shows results of the bend test for a control sample, a sample heated to <NUM>, a sample heated to <NUM>, and a sample heated to <NUM>. Photographs of the samples after the bend test are shown in <FIG>. The sample heated to <NUM> exhibited very high bendability compared to the control sample, indicating that the induction heating or laser heating process described above is useful for improving the bending character of the aluminum during a roll-forming process.

To evaluate the strength performance of the samples, some of the samples were water quenched after the rapid heating process and then subjected to a paint bake cycle, where they were heated and held at <NUM> for <NUM> minutes. After the paint bake cycle, the samples were subjected to strength testing to determine yield strength and ultimate tensile strength. Results of the strength performance are listed in Table <NUM>.

The strength performance results indicate only minor changes in yield strength and ultimate tensile strength, as compared to the control sample, for the samples subjected to rapid heating up to <NUM>. The sample subjected to rapid heating to <NUM> (not according to the invention), however, showed a substantial drop in both yield strength and ultimate tensile strength.

Together, these bend testing and strength performance results indicate that rapid heating can significantly improve the bending performance while only minimally impacting the strength performance. For this alloy, rapid heating to temperatures up to <NUM> provide an up-to about <NUM>-fold bendability improvement with a very small (e.g., less than <NUM>%) impact on the strength.

The foregoing examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof. During the studies described herein, conventional procedures were followed, unless otherwise stated. Some of the procedures are described in detail for illustrative purposes.

Claim 1:
A method of making a metal product (<NUM>, <NUM>, <NUM>), comprising:
exposing an elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), which is a metal sheet, shate or plate, to a first time-varying magnetic field or first laser radiation to heat at least a first portion (<NUM>, <NUM>) of the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) by induction heating or laser heating as the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is moved along a rolling direction (<NUM>, <NUM>) past a first magnetic field source (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) generating the first time-varying magnetic field or laser source (<NUM>) generating the first laser radiation, wherein the first time-varying magnetic field or first laser radiation heats at least the first portion (<NUM>, <NUM>) of the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to a first temperature sufficient to increase formability or plasticity of at least the first portion (<NUM>, <NUM>) of the elongated metal substrate; wherein the first temperature is from <NUM> to <NUM>,
characterized therein by,
passing the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) between at least two rollers of a first roll-forming stand (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to bend the first portion (<NUM>, <NUM>) of the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and
that passing the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) between at least two rollers of the first roll-forming stand (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to bend the first portion (<NUM>, <NUM>) of the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) occurs after the first portion (<NUM>, <NUM>) of the elongated metal substrate (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) cools below the first temperature or to ambient temperature.