METHOD AND APPARATUS FOR HEATING AND ROLL FORMING A PRODUCT

Abstract

Systems and methods are described for roll-forming metal substrates. 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, or exposure to laser radiation from a laser source. Heating of the metal substrates allows 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. Heating of the high-strength metal substrates can also function to temper the substrates and/or improve surface corrosion resistance and form high-strength end products with desirable properties.

Claims

1. A method of making a metal product, comprising: exposing an elongated metal substrate to a first time-varying magnetic field or first laser radiation to heat at least a first portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along a rolling direction past a first magnetic field source generating the first time-varying magnetic field or laser source generating the first laser radiation, wherein the first time-varying magnetic field or 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 at least the first portion of the elongated metal substrate; and passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate.

2. The method of claim 1, wherein passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate occurs while at least the first portion of the elongated metal substrate is heated to or above the first temperature.

3. The method of claim 1, wherein passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate occurs after the first portion of the elongated metal substrate cools below the first temperature or to ambient temperature.

4. The method of claim 1, wherein exposing the elongated metal substrate to the first time-varying magnetic field or the first laser radiation heats an entirety of the elongated metal substrate to or above the first temperature prior to passing the elongated metal substrate between the at least two rollers of the roll-forming stand.

5. (canceled)

6. The method of claim 1, wherein 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 0.1 to 2.

7. The method of claim 1, wherein the first temperature is from 100° C. to 500° C.

8. The method of claim 1, wherein the first time-varying magnetic field or first laser radiation heats 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.

9. The method of claim 1, wherein the first time-varying magnetic field or first laser radiation heats at least the first portion of the elongated metal substrate and overages at least the first portion of the elongated metal substrate.

10. The method of claim 1, wherein the first time-varying magnetic field or first 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.

11. The method of claim 1, further comprising adjusting a distance between the first magnetic field source and the elongated metal substrate to control a rate of heat generated in the elongated metal substrate by the induction heating.

12. (canceled)

13. The method of claim 1, wherein the first magnetic field source comprises one or more permanent magnets coupled to one or more motors for rotating the one or more permanent magnets.

14.-18. (canceled)

19. The method of claim 1, wherein an exposure time of the elongated metal substrate to the first time-varying magnetic field or first laser radiation is from 0.1 seconds to 300 seconds.

20. The method of claim 1, wherein the first magnetic field source comprises one or more electromagnetic coils and one or more power supplies electrically coupled to the one or more electromagnetic coils.

21. (canceled)

22. The method of claim 1, further comprising: exposing the elongated metal substrate to a second time-varying magnetic field or second or laser radiation to heat a second 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 magnetic field source that generates the second time-varying magnetic field or a second laser source that generates the second laser radiation, wherein the second time-varying magnetic field or second laser radiation heats the second portion of the elongated metal surface to or above a second temperature sufficient to increase formability or plasticity of the second 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.

23.-24. (canceled)

25. A system for making a metal product, comprising: a first magnetic field source or first laser source positioned to expose an elongated metal substrate to a first time-varying magnetic field or first laser radiation and heat at least a first portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along a rolling direction past the first magnetic field source or laser source, wherein the first time-varying magnetic field or first laser radiation is configured to heat at least 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; a first roll-forming stand positioned to receive the elongated metal substrate after exposure to the first time-varying magnetic field or laser radiation, wherein the first 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 heated to or above the first temperature or after at least the first portion of the elongated metal substrate is cooled to below the first temperature or to ambient temperature.

26. The system of claim 25, wherein the first roll-forming stand is configured to bend 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 0.1 to 2.

27. The system of claim 25, wherein the first temperature is from 100° C. to 500° C.

28.-30. (canceled)

31. The system of claim 25, further comprising a position actuator coupled to the first magnetic field source for adjusting a distance between the first magnetic field source and the elongated metal substrate to control a rate of heat generated in the elongated metal substrate by the induction heating.

32. (canceled)

33. The system of claim 25, wherein the first magnetic field source comprises one or more permanent magnets coupled to one or more motors for rotating the one or more permanent magnets or wherein the first magnetic field source comprises one or more electromagnetic coils and one or more power supplies electrically coupled to the one or more electromagnetic coils.

34.-41. (canceled)

42. The system of claim 25, further comprising: a second magnetic field source or second laser source positioned to expose the elongated metal substrate to a second time-varying magnetic field or second laser radiation and heat a second portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along the rolling direction past the second magnetic field source or second laser source, wherein the second magnetic field source or second laser source is positioned to heat the second portion of the elongated metal substrate to or above a second temperature sufficient to increase formability or plasticity of the second 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.

43.-46. (canceled)

Description

BRIEF DESCRIPTION OF THE FIGURES

[0018] The specification makes reference to the following appended figures, in which use of like reference numerals in different figures is intended to illustrate like or analogous components.

[0019] FIG. 1 provides a schematic illustration of a series of roll-forming stands and induction and laser heating systems for roll-forming of an elongated metal substrate.

[0020] FIG. 2A, FIG. 2B, and FIG. 2C provide schematic illustrations of roll-forming and induction heating of an elongated metal substrate.

[0021] FIG. 3 provides an example plot showing relative temperature of an elongated metal substrate as a function of x position of the metal substrate.

[0022] FIG. 4 provides an example plot showing relative temperature of an elongated metal substrate as a function of y position of the metal substrate.

[0023] FIG. 5 provides a schematic illustration of progressive roll-forming of an elongated metal substrate using a series of roll-forming stands.

[0024] FIG. 6 provides a schematic illustration of a series of roll-forming stands with a rotating magnet induction heating system for pre-heating the elongated metal substrate prior to roll-forming with electromagnetic induction heating systems between some roll-forming stands.

[0025] FIG. 7 provides a schematic illustration of progressive roll-forming of an elongated metal substrate after pre-heating using a rotating magnet induction heating system with electromagnetic induction heating systems between some roll-forming stands.

[0026] FIG. 8A provides data showing outer bending angle for aluminum samples subjected to rapid heating followed by a bend test. FIG. 8B shows photographs of the aluminum samples after the bend test.

DETAILED DESCRIPTION

[0027] 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.

[0028] 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 1.5 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.

[0029] 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.

[0030] 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.

[0031] 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 may be 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 may be 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.

[0032] 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. U.S. patent application Ser. No. 15/716,887, filed on Sep. 27, 2017, and published under publication number US 2018/0092163 on Mar. 29, 2018, is hereby incorporated by reference and describes additional details regarding use of rotating magnets for heat generation by induction.

Definitions and Descriptions

[0033] 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. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below.

[0034] 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.

[0035] As used herein, a plate generally has a thickness of greater than about 15 mm. For example, a plate may refer to an aluminum product having a thickness of greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm.

[0036] As used herein, a shate (also referred to as a sheet plate) generally has a thickness of from about 4 mm to about 15 mm. For example, a shate may have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

[0037] As used herein, a sheet generally refers to an aluminum product having a thickness of less than about 4 mm. For example, a sheet may have a thickness of less than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1 mm, less than about 0.5 mm, or less than about 0.3 mm (e.g., about 0.2 mm).

[0038] 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.

[0039] 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.

[0040] 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.

[0041] As used herein, the meaning of “room temperature” can include a temperature of from about 15° C. to about 30° C., for example about 15° C., about 16° C., about 17° C., about 18° C., about 19° C., about 20° C., about 21° C., about 22° C., about 23° C., about 24° C., about 25° C., about 26° C., about 27° C., about 28° C., about 29° C., or about 30° C. As used herein, the meaning of “ambient conditions” can include temperatures of about room temperature, relative humidity of from about 20% to about 100%, and barometric pressure of from about 975 millibar (mbar) to about 1050 mbar. For example, relative humidity can be about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 100%, or anywhere in between. For example, barometric pressure can be about 975 mbar, about 980 mbar, about 985 mbar, about 990 mbar, about 995 mbar, about 1000 mbar, about 1005 mbar, about 1010 mbar, about 1015 mbar, about 1020 mbar, about 1025 mbar, about 1030 mbar, about 1035 mbar, about 1040 mbar, about 1045 mbar, about 1050 mbar, or anywhere in between.

[0042] All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g. 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10. 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.

[0043] As used herein, the meaning of “a,” “an,” and “the” includes singular and plural references unless the context clearly dictates otherwise.

Methods of Producing Metal Substrates

[0044] 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.

[0045] 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.

[0046] 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.

Methods and Systems for Making Metal Products

[0047] 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 1.5-1000 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.

[0048] 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.

[0049] 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.

[0050] FIG. 1 provides a schematic illustration of a system 100 for making metal products. Elongated metal substrate 105 is shown moving along direction 110 through system 100. System 100 includes a plurality of roll-forming stands 115, a plurality of magnetic field sources 120, and a plurality of laser sources 135. A bent metal product 130 exits the system 100 after all roll-forming stands 115. Although elongated metal substrate 105 is shown as originating from a coil, other configurations may include processing elongated metal substrate as a metal blank or a metal strip.

[0051] Each roll-forming stand 115 may include two or more rollers driven along independent rotation axes in a configuration to receive and pass elongated metal substrate 105 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 110, the elongated metal substrate 105 as it passes between the rollers along direction 110. Optionally, each roll-forming stand 115 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 115, 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 115. Each roll-forming stand 115 may be different from other roll-forming stands 115, such as to allow for different bend operations to occur at each roll-forming stand 115.

[0052] Each magnetic field source 120 may generate a time-varying magnetic field to heat a portion of elongated metal substrate 105 via induction heating. Each laser source 130 may generate laser radiation and expose and heat a portion of elongated metal substrate 105 via laser heating. Depending on the configuration, different portions of elongated metal substrate 105 may be heated by the different magnetic field sources 120 and/or laser sources 135. The magnetic field sources 120 and/or laser sources 135 may be positioned before and/or after roll-forming stands 115. In some cases, magnetic field sources 120 and/or laser sources 135 may not be positioned before or after every roll-forming stand 115. The magnetic field sources 120 and/or laser sources 135 may be independently positioned on a top side or bottom side of the elongated metal substrate 105. A position of the magnetic field sources 120 and/or laser sources 135 may, at least in part, be governed by the particular bend operation achieved by the roll-forming stands 115. For example, an interior bend surface of elongated metal substrate 105 may face an magnetic field source 120 and/or laser source 135 positioned before and/or after a roll-forming stand 115. As another example, in some cases, an exterior bend surface of elongated metal substrate 105 may face an magnetic field source 120 and/or laser source 135 positioned before and/or after a roll-forming stand 115. Although a combination of magnetic field sources 120 and laser source 135 are shown in system 100, magnetic field sources 120 and laser source 135 may be used alone or in any combination in any desirable number. For example, system 100 may comprise one or multiple magnetic field sources 120 and no laser sources 135. As another example, system 100 may comprise one or multiple laser sources 135 and no magnetic field sources 120.

[0053] The heating may increase a temperature of a portion of elongated metal substrate 105 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 105. Optionally, the heating may overage the portion of the elongated metal substrate 105. Optionally, the heating may modify (e.g., increase) a corrosion resistance of the portion of the elongated metal substrate 105. The heating may raise the temperature of the portion of the elongated metal substrate 105 to, for example, between 50° C. and 400° C., such as between 100° C. and 300° C. Optionally, the temperature of the elongated metal substrate 105 may be 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 0.1 seconds and 600 seconds, 0.1 seconds and 500 seconds, 0.1 seconds and 400 seconds, 0.1 seconds and 300 seconds, 0.1 seconds and 200 seconds, 0.1 seconds and 100 seconds, 0.1 seconds and 50 seconds, 0.1 seconds and 10 seconds, or 0.1 seconds and 5 seconds.

[0054] FIG. 2A, FIG. 2B, and FIG. 2C provide schematic illustrations showing a roll-forming process performed by a roll-forming system 200 including a single roll-forming stand. FIG. 2A provides a side view of roll-forming system 200, FIG. 2B provides a perspective view of roll-forming system 200, and FIG. 2C provides a top view of roll-forming system 200. An elongated metal substrate 205 passes along direction 210 (illustrated as parallel to the y-axis) between rollers 215 of a roll-forming stand to form a bent metal product 230. A width of elongated metal substrate 205 is illustrated as parallel to the x-axis, with a thickness of elongated metal substrate 205 illustrated as parallel to the z-axis. Two magnetic field sources 220 are positioned to expose elongated metal substrate 205 to time-varying magnetic fields to heat portion 225 of elongated metal substrate 205 by induction heating.

[0055] In FIG. 2A, magnetic field sources 220 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 220 and elongated metal substrate 205 can be independently adjusted. An adjustable distance between the magnetic field sources 220 and the elongated metal substrate 205 may be useful for controlling a rate of heat generation in the portion 225 of elongated metal substrate 205 by induction heating.

[0056] In FIG. 2B, magnetic field sources 220 are also illustrated as a rotating permanent magnet, but with a different geometry than that shown in FIG. 2A, 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 205.

[0057] In FIG. 2C, magnetic field sources 220 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 225 of elongated metal substrate 205.

[0058] Although FIGS. 2A-2C show magnetic field sources 220, laser sources may be substituted for any one or more or all of the magnetic field sources 220, without limitation.

[0059] FIG. 3 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. 3 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. 3 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 305, 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 0 and 1) of elongated metal substrate may be higher than ambient conditions, due to heat conduction from heated portion 305 towards the edges of the elongated metal substrate. Within heated portion 305, the temperature may be at or above a suitable temperature 310 for achieving a target formability or plasticity in the heated portion 305 of the elongated metal substrate. In some embodiments, only heated portion 305 is heated above the ambient or minimum temperature, with a relatively uniform temperature across heated portion 305 at a target temperature suitable for a desired formability, a desired plasticity, a desired temper modification, a desired corrosion resistance property modification, etc.

[0060] FIG. 4 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 305 (e.g., a center point within heated portion 305). It will be appreciated that the temperature distribution shown in FIG. 4 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. 4 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 415. 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 415, the temperature may decrease by conductive or convective heat loss. Roll-forming may take place immediately following region 415 or may take place at a greater y-position, for example. 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 415 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 415, which may be useful for achieving a target time duration for subjecting the portion of the elongated metal substrate to increased temperatures.

[0061] 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.

[0062] As an example, for a 3xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. may be from 50° C. to 400° C., such as from 100° C. to 300° C. or from 150° C. to 250° C. As another example, for a 4xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. may be from 50° C. to 400° C., such as from 100° C. to 300° C. or from 150° C. to 250° C. As another example, for a 5xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. may be from 50° C. to 400° C., such as from 100° C. to 300° C. or from 150° C. to 250° C. As another example, for a 6xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. may be from 50° C. to 400° C., such as from 100° C. to 300° C. or from 150° C. to 250° C. As another example, for a 7xxx series aluminum alloy, a target temperature for modifying formability, temper condition, corrosion resistance property, etc. may be from 50° C. to 400° C., such as from 100° C. to 300° C. or from 150° C. to 250° C.

[0063] 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 0.5 cm and 5 cm. As another example, a rotating permanent magnet may have a length or thickness of between 0.5 cm and 30 cm. As another example, a rotating permanent magnet may have a surface field strength of between 1000 Gauss and 10000 Gauss. As another example, a rotating permanent magnet may have a residual flux density of between 10000 Gauss and 15000 Gauss. As another example, a rotating permanent magnet may be rotated at a rate of between 100 revolutions per minute and 30000 revolutions per minute.

[0064] 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 0.5 cm and 30 cm. As an example, an electromagnetic coil may have a number of turns per inch of between 0.5 and 1000. As another example, an electromagnetic coil may be energized using an AC voltage of between 1 V and 1000 V. As another example, an electromagnetic coil may be energized using an AC voltage having a frequency of between 50 Hz and 100 kHz. As another example, an electromagnetic coil may be energized using an AC current of between 1 A and 100 A.

[0065] 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.sub.2 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 1 mm to 10 mm. 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 1 W to 5 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] FIG. 5 provides a schematic illustration showing a roll-forming system 500 including three roll-forming stands. As illustrated in FIG. 5, an elongated metal substrate 505 passes between rollers 515-1, 515-2, and 515-3 (collectively, rollers 515) of the roll-forming stands. At each roll-forming stand, elongated metal substrate is roll-formed into a bent configuration. Magnetic field sources 520-1, 520-2, and 520-3 (collectively, magnetic field sources 520) are positioned adjacent to elongated metal substrate 505 to expose elongated metal substrate 505 to time-varying magnetic fields to heat portions 525-1, 525-2, and 525-3 (collectively, portions 525) of elongated metal substrate 505 by induction heating.

[0072] Although magnetic field sources 520 are shown as positioned above elongated metal substrate 505, configurations are contemplated where some or all magnetic field sources 520 are positioned below elongated metal substrate 505. Magnetic field sources 520 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. 5). An adjustable distance between the magnetic field sources 520 and the elongated metal substrate 505 may be useful for controlling a rate of heat generation in the portions 525 of elongated metal substrate 505 by induction heating.

[0073] Different positions along the width dimension of elongated metal substrate 505 for each of the magnetic field sources 520 and portions 525 are illustrated in FIG. 5. The positions of magnetic field sources 520 and portions 525 are shown as overlapping with the portion of the elongated metal substrate 505 to be bent by each roll-forming stand. For example, the first roll-forming stand forms first bends 530 in elongated metal substrate 505, which are positioned along the width direction in line with magnetic field sources 520-1 and portions 525-1. The second roll-forming forming stand forms second bends 535 in elongated metal substrate 505, which are positioned along the width direction in line with magnetic field sources 520-2 and portions 525-2. The third bends 540 in elongated metal substrate 505 are shown as overlapping with first bends 530, but have an opposite bend direction. Third bends 540 are positioned along the width direction in line with magnetic field sources 520-3 and portions 525-3.

[0074] In FIG. 5, one additional magnetic field source 545 is illustrated after the third roll-forming stand including rollers 515-3. Magnetic field source 545 is oriented to heat portion 550 of elongated metal substrate 505, which extends substantially entirely along the width. Such a configuration may be useful for heating the entirety of elongated metal substrate 505 as it travels past magnetic field source 545. For example, such a configuration may be useful for heating elongated metal substrate 505 to achieve or modify an overall temper condition or to achieve or modify an overall corrosion resistance character.

[0075] Although FIG. 5 shows magnetic field sources 520-1, 520-2, 520-3, and 545, laser sources may be substituted for any one or more or all of the magnetic field sources 520-1, 520-2, 520-3, and 545, without limitation.

[0076] FIG. 6 provides a schematic illustration of another system 600 for making metal products where preheating of an elongated metal substrate 605 using an induction system 620 is used. Elongated metal substrate 605 is shown moving along direction 610 through system 600. Induction system 620 can comprise a series of permanent magnet rotors 621 arranged adjacent to elongated metal substrate 605 as it passes through induction system 620. Induction system 620 can include rollers 622 to allow for drawing the elongated metal substrate 605 along different directions, so as to allow more linear length and space for interaction with permanent magnetic rotors 621 while reducing the footprint of induction system 620. System 600 also includes a plurality of roll-forming stands 615 and optionally includes additional magnetic field sources 625. A bent metal product 630 exits the system 600 after all roll-forming stands 615. Although elongated metal substrate 605 is shown as originating from a coil, other configurations may include processing elongated metal substrate as a metal blank or a metal strip.

[0077] Each roll-forming stand 615 may include two or more rollers driven along independent rotation axes in a configuration to receive and pass elongated metal substrate 605 between the rollers. With induction system 620 provided upstream of roll-forming stands 615, a temperature of elongated metal substrate 605 may be raised to a temperature suitable to increase the formability of the elongated metal substrate 605 prior to any roll forming occurring by roll-forming stand 615. In this way, elongated metal substrate 605 can be in a fully preheated condition prior to entering the first roll-forming stand 615.

[0078] Each magnetic field source 625 may be used to add additional heat to elongated metal substrate 605 via induction heating. Although magnetic field sources 625 are depicted as electromagnetic coils in FIG. 6, in some cases one or more of the magnetic field sources 625 may comprise rotating permanent magnets, similar to permanent magnetic rotors 621. In some cases, the magnetic field sources 625 can add heat along a full width of the elongated metal substrate 605 as it moves past magnetic field sources 625, for example to maintain a temperature of the elongated metal substrate 605 after preheating by induction system 620 due to heat losses at roll-forming stands 615 or due to heat losses to the environment. In some cases, the magnetic field sources 625 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 615. In some cases, heat added by a magnetic field source 625 may be at a local position along the width of the elongated metal substrate 605. As shown, the magnetic field sources 625 may be positioned before and/or after roll-forming stands 615. In some cases, magnetic field sources 625 may not be positioned before or after every roll-forming stand 615. The magnetic field sources 625 may be independently positioned on a top side or bottom side of the elongated metal substrate 605.

[0079] FIG. 7 provides a schematic illustration showing a roll-forming system 700 including three roll-forming stands, similar to roll-forming system 500 shown in FIG. 5. As illustrated in FIG. 7, an elongated metal substrate 705 passes between a pair of permanent magnetic rotors 710 to preheat elongated metal substrate 705 across its full width. Although a single pair of permanent magnetic rotors 710 is shown in FIG. 7, any suitable number of permanent magnetic rotors may be used, with the configuration shown in FIG. 7 simply representing one pair of permanent magnetic rotors 710 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 U.S. patent application Ser. No. 15/716,887, filed on Sep. 27, 2017, which is hereby incorporated by reference.

[0080] After preheating by the pair of permanent magnetic rotors 710, elongated metal substrate 705 passes through rollers 715 of different roll-forming stands. At each roll-forming stand, elongated metal substrate 705 is roll-formed into different bent configurations.

[0081] Magnetic field sources 720, depicted as electromagnetic coils, are shown positioned adjacent to elongated metal substrate 705 at various points to expose elongated metal substrate 705 to time-varying magnetic fields to further add heat to elongated metal substrate 705 by induction heating. Although magnetic field sources 720 are shown as positioned above elongated metal substrate 705, configurations are contemplated where some or all magnetic field sources 720 are positioned below elongated metal substrate 705. Although FIG. 7 shows magnetic field sources 720 and permanent magnetic rotors 710, laser sources may be substituted for any one or more or all of the magnetic field sources 720 and permanent magnetic rotors 710, without limitation.

Methods of Using Metal Products

[0082] 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.

[0083] 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.

[0084] Aspects of the invention may be further understood by reference to the following non-limiting examples.

Example 1

[0085] Samples of a 7075 aluminum alloy sheet with a thickness of 2.8 mm were obtained in a T6 temper condition (e.g., by tempering at 125° C. for 24 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 150° C., 200° C., 250° C., and 300° C. were used. As a control, some samples were not subjected to heating.

[0086] To evaluate the bending performance of the samples under roll-forming conditions, some of the sample samples were subjected to a 3 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 (a) was measured manually afterwards. FIG. 8A shows results of the bend test for a control sample, a sample heated to 150° C., a sample heated to 200° C., and a sample heated to 250° C. Photographs of the samples after the bend test are shown in FIG. 8B. The sample heated to 250° C. 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.

[0087] 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 180° C. for 30 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 1.

TABLE-US-00001 TABLE 1 Strength performance results Ultimate Yield Tensile Strength Strength Rapid Heating (MPa) (MPa) Control Sample: No Rapid Heating 503.237 560.863 T6 + Paint Bake Test Samples: 150° C. .fwdarw. Water Quench 494.400 545.800 T6 + Rapid 200° C. .fwdarw. Water Quench 495.700 546.130 Heating + Paint 250° C. .fwdarw. Water Quench 513.030 548.500 Bake 300° C. .fwdarw. Water Quench 352.200 447.960

[0088] 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 250° C. The sample subjected to rapid heating to 300° C., however, showed a substantial drop in both yield strength and ultimate tensile strength.

[0089] 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 250° C. provide an up-to about 8-fold bendability improvement with a very small (e.g., less than 3%) impact on the strength.

[0090] The foregoing examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof. On the contrary, it is to be clearly understood that resort may be had to various embodiments, modifications and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention. During the studies described herein, conventional procedures were followed, unless otherwise stated. Some of the procedures are described in detail for illustrative purposes.

[0091] All patents, publications and abstracts cited above are incorporated herein by reference in their entirety. The foregoing description of the embodiments, including illustrated embodiments, has been presented only for the purpose of illustration and description and is not intended to be exhaustive or limiting to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art.

ILLUSTRATIVE ASPECTS

[0092] As used below, any reference to a series of aspects (e.g., “Aspects 1-4”) or non-enumerated group of aspects (e.g., “any previous or subsequent aspect”) is to be understood as a reference to each of those aspects disjunctively (e.g., “Aspects 1-4” is to be understood as “Aspects 1, 2, 3, or 4”).

[0093] Aspect 1 is a method of making a metal product, comprising: exposing an elongated metal substrate to a first time-varying magnetic field or first laser radiation to heat at least a first portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along a rolling direction past a first magnetic field source or generating the first time-varying magnetic field or laser source generating the first laser radiation, wherein the first time-varying magnetic field heats or first laser radiation at least 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; and passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate.

[0094] Aspect 2 is the method of any previous or subsequent aspect, wherein passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate occurs while at least the first portion of the elongated metal substrate is heated to or above the first temperature.

[0095] Aspect 3 is the method of any previous or subsequent aspect, wherein passing the elongated metal substrate between at least two rollers of a first roll-forming stand to bend the first portion of the elongated metal substrate occurs after the first portion of the elongated metal substrate cools below the first temperature or to ambient temperature.

[0096] Aspect 4 is the method of any previous or subsequent aspect, wherein exposing the elongated metal substrate to the first time-varying magnetic field or the first laser radiation heats an entirety of the elongated metal substrate to or above the first temperature prior to passing the elongated metal substrate between the at least two rollers of the roll-forming stand.

[0097] Aspect 5 is the method of any previous or subsequent aspect, wherein a temperature of the roll-forming stand or the at least two rollers of the roll-forming stand is less than the first temperature.

[0098] Aspect 6 is the method of any previous or subsequent aspect, wherein 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 0.1 to 2.

[0099] Aspect 7 is the method of any previous or subsequent aspect, wherein the first temperature is from 100° C. to 500° C., wherein the first temperature is from 150° C. to 250° C., or wherein the first temperature is from 350° C. to 450° C.

[0100] Aspect 8 is the method of any previous or subsequent aspect, wherein the first time-varying magnetic field or first laser radiation heats 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.

[0101] Aspect 9 is the method of any previous or subsequent aspect, wherein the first time-varying magnetic field or first laser radiation heats at least the first portion of the elongated metal substrate and overages at least the first portion of the elongated metal substrate.

[0102] Aspect 10 is the method of any previous or subsequent aspect, wherein the first time-varying magnetic field or first 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.

[0103] Aspect 11 is the method of any previous or subsequent aspect, further comprising adjusting a distance between the first magnetic field source and the elongated metal substrate to control a rate of heat generated in the elongated metal substrate by the induction heating.

[0104] Aspect 12 is the method of any previous or subsequent aspect, wherein the distance between the first magnetic field source and the elongated metal substrate ranges from 1 mm to 60 mm.

[0105] Aspect 13 is the method of any previous or subsequent aspect, wherein the first magnetic field source comprises one or more permanent magnets coupled to one or more motors for rotating the one or more permanent magnets.

[0106] Aspect 14 is the method of any previous or subsequent aspect, wherein the one or more permanent magnets are arranged about a cylindrical structure, and wherein the cylindrical structure is rotated about a cylindrical axis to expose the elongated metal substrate to the first time-varying magnetic field.

[0107] Aspect 15 is the method of any previous or subsequent aspect, wherein the one or more motors have adjustable speeds for controlling the first time-varying magnetic field.

[0108] Aspect 16 is the method of any previous or subsequent aspect, wherein the one or more motors have rotation speeds of from 100 revolutions per minute to 30000 revolutions per minute.

[0109] Aspect 17 is the method of any previous or subsequent aspect, wherein the one or more permanent magnets have surface field strengths of from 1000 Gauss to 10000 Gauss.

[0110] Aspect 18 is the method of any previous or subsequent aspect, wherein the one or more permanent magnets have residual flux densities of from 10000 Gauss to 15000 Gauss.

[0111] Aspect 19 is the method of any previous or subsequent aspect, wherein the first laser source comprises a diode laser, a fiber laser, a CO.sub.2 laser, a YAG laser, an excimer laser, a dye laser, or an ion laser.

[0112] Aspect 20 is the method of any previous or subsequent aspect, wherein the first laser radiation has an output power of from 1 W to 5 kW or wherein the first laser radiation has a spot size of from 1 mm to 10 mm.

[0113] Aspect 21 is the method of any previous or subsequent aspect, wherein the first laser radiation passes through a dispersing optic or a homogenizing optic to spread the first laser radiation across a width direction of the elongated metal substrate.

[0114] Aspect 22 is the method of any previous or subsequent aspect, wherein an exposure time of the elongated metal substrate to the first time-varying magnetic field or first laser radiation is from 0.1 seconds to 300 seconds.

[0115] Aspect 23 is the method of any previous or subsequent aspect, wherein the first magnetic field source comprises one or more electromagnetic coils and one or more power supplies electrically coupled to the one or more electromagnetic coils.

[0116] Aspect 24 is the method of any previous or subsequent aspect, wherein the one or more power supplies have one or more of a variable output voltage, a variable output current, or a variable output frequency for controlling the first time-varying magnetic field.

[0117] Aspect 25 is the method of any previous or subsequent aspect, further comprising: exposing the elongated metal substrate to a second time-varying magnetic field or second or laser radiation to heat a second 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 magnetic field source that generates the second time-varying magnetic field or a second laser source that generates the second laser radiation, wherein the second time-varying magnetic field or second laser radiation heats the second portion of the elongated metal surface to or above a second temperature sufficient to increase formability or plasticity of the second 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.

[0118] Aspect 26 is the method of any previous or subsequent aspect, wherein 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.

[0119] Aspect 27 is the method of any previous or subsequent aspect, wherein 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.

[0120] Aspect 28 is a system for making a metal product, comprising: a first magnetic field source or first laser source positioned to expose an elongated metal substrate to a first time-varying magnetic field or first laser radiation and heat at least a first portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along a rolling direction past the first magnetic field source or laser source, wherein the first time-varying magnetic field or 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 at least the first portion of the elongated metal substrate; a first roll-forming stand positioned to receive the elongated metal substrate after exposure to the first time-varying magnetic field or laser radiation, wherein the first 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 heated to or above the first temperature or after at least the first portion of the elongated metal substrate is cooled to below the first temperature or to ambient temperature.

[0121] Aspect 29 is the system of any previous or subsequent aspect, wherein 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 0.1 to 2.

[0122] Aspect 30 is the system of any previous or subsequent aspect, wherein the first temperature is from 100° C. to 500° C., wherein the first temperature is from 150° C. to 250° C., or wherein the first temperature is from 350° C. to 450° C.

[0123] Aspect 31 is the system of any previous or subsequent aspect, wherein the first time-varying electromagnetic field or first laser radiation heats 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 at least the first portion of the elongated metal substrate.

[0124] Aspect 32 is the system of any previous or subsequent aspect, wherein the first time-varying electromagnetic field or first laser radiation heats at least the first portion of the elongated metal substrate to overage at least the first portion of the elongated metal substrate.

[0125] Aspect 33 is the system of any previous or subsequent aspect, wherein the first time-varying electromagnetic field or first laser radiation heats at least the first portion of the elongated metal substrate to modify a corrosion resistance of at least the first portion of the elongated metal substrate.

[0126] Aspect 34 is the system of any previous or subsequent aspect, further comprising a position actuator coupled to the first magnetic field source for adjusting a distance between the first magnetic field source and the elongated metal substrate to control a rate of heat generated in the elongated metal substrate by the induction heating.

[0127] Aspect 35 is the system of any previous or subsequent aspect, wherein the distance between the first magnetic field source and the elongated metal substrate ranges from 1 mm to 60 mm.

[0128] Aspect 36 is the system of any previous or subsequent aspect, wherein the first magnetic field source comprises one or more permanent magnets coupled to one or more motors for rotating the one or more permanent magnets.

[0129] Aspect 37 is the system of any previous or subsequent aspect, wherein the one or more permanent magnets are one or more cylindrical magnet and wherein the one or more permanent magnets are rotated about a cylindrical axis.

[0130] Aspect 38 is the system of any previous or subsequent aspect, wherein the one or more motors have adjustable speeds for controlling the first time-varying magnetic field.

[0131] Aspect 39 is the system of any previous or subsequent aspect, wherein the one or more motors have rotation speeds of from 100 revolutions per minute to 30000 revolutions per minute.

[0132] Aspect 40 is the system of any previous or subsequent aspect, wherein the one or more permanent magnets have surface field strengths of from 1000 Gauss to 10000 Gauss.

[0133] Aspect 41 is the system of any previous or subsequent aspect, wherein the one or more permanent magnets have residual flux densities of from 10000 Gauss to 15000 Gauss.

[0134] Aspect 42 is the system of any previous or subsequent aspect, wherein the first laser source comprises a diode laser, a fiber laser, a CO.sub.2 laser, a YAG laser, an excimer laser, a dye laser, or an ion laser.

[0135] Aspect 43 is the system of any previous or subsequent aspect, wherein the first laser radiation has an output power of from 1 W to 5 kW or wherein the first laser radiation has a spot size of from 1 mm to 10 mm.

[0136] Aspect 44 is the system of any previous or subsequent aspect, wherein the first laser source comprises a dispersing optic or a homogenizing optic arranged to spread the first laser radiation across a width direction of the elongated metal substrate.

[0137] Aspect 45 is the system of any previous or subsequent aspect, wherein an exposure time of the metal substrate to the first time-varying magnetic field is from 0.1 seconds to 300 seconds.

[0138] Aspect 46 is the system of any previous or subsequent aspect, wherein the first magnetic field source comprises one or more electromagnetic coils and one or more power supplies electrically coupled to the one or more electromagnetic coils.

[0139] Aspect 47 is the system of any previous or subsequent aspect, wherein the power supply has one or more of a variable output voltage, a variable output current, or a variable output frequency for controlling the first time-varying magnetic field.

[0140] Aspect 48 is the system of any previous or subsequent aspect, further comprising: a second magnetic field source or second laser source positioned to expose the elongated metal substrate to a second time-varying magnetic field or second laser radiation and heat a second portion of the elongated metal substrate by induction heating or laser heating as the elongated metal substrate is moved along the rolling direction past the second magnetic field source or second laser source, wherein the second magnetic field source or second laser source is positioned to heat the second portion of the elongated metal substrate to or above a second temperature sufficient to increase formability or plasticity of the second 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.

[0141] Aspect 49 is the system of any previous or subsequent aspect, wherein 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.

[0142] Aspect 50 is the system of any previous or subsequent aspect, wherein 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.

[0143] Aspect 51 is a metal product formed using the method of any previous aspect or the system of any previous aspect.

[0144] Aspect 52 is the metal product of any previous aspect, wherein the metal product comprises an automotive structural product.