Patent Application
20230211401
The present disclosure relates to metallurgy generally and more specifically to roll-forming high strength metal substrates.
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.
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. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this disclosure, any or all drawings and each claim.
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 can be, at least temporarily, modified by heating the metal prior to or immediately prior to roll-forming. The roll-forming process may form the metal while the metal to be formed, or a portion of it, is in a heated condition or after cooling back 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. An example method of this aspect comprises exposing an elongated metal substrate 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 may occur 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 may heat 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 may be passed between at least two rollers of a first roll-forming stand to 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 the at least the first portion of the elongated metal substrate cools from the first temperature. Optionally, the first temperature is from 50° C. to 500° C., such as from 50° C. to 100° C., from 50° C. to 200° C., from 50° C. to 300° C., from 100° C. to 200° C., from 100° C. to 300° C., from 100° C. to 400° C., from 200° C. to 300° C., from 200° C. to 400° C., from 300° C. to 400° C., from 400° C. to 500° C., from 150° C. to 250° C., from 350° C. to 450° C., or from 450° C. to 480° C. 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 150° C. to 250° C., from 150° C. to 160° C., from 160° C. to 170° C., from 170° C. to 180° C., from 180° C. to 190° C., from 190° C. to 200° C., from 200° C. to 210° C., from 210° C. to 220° C., from 220° C. to 230° C., from 230° C. to 240° C., or from 240° C. to 250° C. when the elongated metal substrate comprises a 7xxx series alloy. In other examples, the first temperature may be from 350° C. to 450° C., from 350° C. to 360° C., from 360° C. to 370° C., from 370° C. to 380° C., from 380° C. to 390° C., from 390° C. to 400° C., from 400° C. to 410° C., from 410° C. to 420° C., from 420° C. to 430° C., from 430° C. to 440° C., or from 440° C. to 450° C. when the elongated metal substrate comprises a 6xxx 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 0.1 to 2, such as from 0.1 to 0.5, from 0.1 to 1, from 0.1 to 1.5, from 0.5 to 1, from 0.5 to 1, from 0.5 to 1.5, from 0.5 to 2, from 1 to 1.5, from 1 to 2, or from 1.5 to 2.
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 1 mm to 100 mm, such as from 1 mm to 3 mm, from 1 mm to 5 mm, from 1 mm to 10 mm, from 1 mm to 30 mm, from 1 mm to 40 mm, from 1 mm to 50 mm, from 1 mm to 60 mm, from 1 mm to 70 mm, from 1 mm to 80 mm, from 1 mm to 90 mm, from 3 mm to 5 mm, from 3 mm to 10 mm, from 3 mm to 30 mm, from 3 mm to 40 mm, from 3 mm to 50 mm, from 3 mm to 60 mm, from 3 mm to 70 mm, from 3 mm to 80 mm, from 3 mm to 90 mm, from 3 mm to 100 mm, from 5 mm to 10 mm, from 5 mm to 30 mm, from 5 mm to 40 mm, from 5 mm to 50 mm, from 5 mm to 60 mm, from 5 mm to 70 mm, from 5 mm to 80 mm, from 5 mm to 90 mm, from 5 mm to 100 mm, from 10 mm to 30 mm, from 10 mm to 40 mm, from 10 mm to 50 mm, from 10 mm to 60 mm, from 10 mm to 70 mm, from 10 mm to 80 mm, from 10 mm to 90 mm, from 10 mm to 100 mm, from 30 mm to 40 mm, from 30 mm to 50 mm, from 30 mm to 60 mm, from 30 mm to 70 mm, from 30 mm to 80 mm, from 30 mm to 90 mm, from 30 mm to 100 mm, from 40 mm to 50 mm, from 40 mm to 60 mm, from 40 mm to 70 mm, from 40 mm to 80 mm, from 40 mm to 90 mm, from 40 mm to 100 mm, from 50 mm to 60 mm, from 50 mm to 70 mm, from 50 mm to 80 mm, from 50 mm to 90 mm, from 50 mm to 100 mm, from 60 mm to 70 mm, from 60 mm to 80 mm, from 60 mm to 90 mm, from 60 mm to 100 mm, from 70 mm to 80 mm, from 70 mm to 90 mm, from 70 mm to 100 mm, from 80 mm to 90 mm, from 80 mm to 100 mm, or from 90 mm to 100 mm. 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 5 mm to 50 mm, such as from 5 mm to 10 mm, from 10 mm to 15 mm, from 15 mm to 20 mm, from 20 mm to 25 mm, from 25 mm to 30 mm, from 30 mm to 35 mm from 35 mm to 40 mm, from 40 mm to 45 mm, or from 45 mm to 50 mm. 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 0.1 seconds to 600 seconds, such as from 0.1 seconds to 500 seconds, from 0.1 seconds to 400 seconds, from 0.1 seconds to 300 seconds, from 0.1 seconds to 200 seconds, from 0.1 seconds to 100 seconds, from 0.1 seconds to 50 seconds, from 0.1 seconds to 10 seconds, form 0.1 seconds to 5 seconds, from 0.1 seconds to 1 second, from 1 second to 600 seconds, from 1 second to 500 seconds, from 1 second to 400 seconds, from 1 second to 300 seconds, from 1 second to 200 seconds, from 1 second to 100 seconds, from 1 second to 50 seconds, from 1 second to 10 seconds, form 1 second to 5 seconds, from 5 seconds to 600 seconds, from 5 seconds to 500 seconds, from 5 seconds to 400 seconds, from 5 seconds to 300 seconds, from 5 seconds to 200 seconds, from 5 seconds to 100 seconds, from 5 seconds to 50 seconds, from 5 seconds to 10 seconds, from 10 seconds to 600 seconds, from 10 seconds to 500 seconds, from 10 seconds to 400 seconds, from 10 seconds to 300 seconds, from 10 seconds to 200 seconds, from 10 seconds to 100 seconds, from 10 seconds to 50 seconds, from 50 seconds to 600 seconds, from 50 seconds to 500 seconds, from 50 seconds to 400 seconds, from 50 seconds to 300 seconds, from 50 seconds to 200 seconds, from 50 seconds to 100 seconds, from 100 seconds to 600 seconds, from 100 seconds to 500 seconds, from 100 seconds to 400 seconds, from 100 seconds to 300 seconds, from 100 seconds to 200 seconds, from 200 seconds to 600 seconds, from 200 seconds to 500 seconds, from 200 seconds to 400 seconds, from 200 seconds to 300 seconds, from 300 seconds to 600 seconds, from 300 seconds to 500 seconds, from 300 seconds to 400 seconds, from 400 seconds to 600 seconds, from 400 seconds to 500 seconds, or from 500 seconds to 600 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 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 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 1 revolution per minute to 30000 revolutions per minute, such as from 10 revolutions per minute to 30000 revolutions per minute, from 100 revolutions per minute to 30000 revolutions per minute, from 1000 revolutions per minute to 30000 revolutions per minute, from 10000 revolutions per minute to 30000 revolutions per minute, from 1 revolution per minute to 10000 revolutions per minute, from 10 revolutions per minute to 10000 revolutions per minute, from 100 revolutions per minute to 10000 revolutions per minute, from 1000 revolutions per minute to 10000 revolutions per minute, from 1 revolution per minute to 1000 revolutions per minute, from 10 revolutions per minute to 1000 revolutions per minute, from 100 revolutions per minute to 1000 revolutions per minute, from 1 revolution per minute to 100 revolutions per minute, from 10 revolutions per minute to 100 revolutions per minute, or from 1 revolutions per minute to 10 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 1000 Gauss to 10000 Gauss, such as from 1000 Gauss to 2000 gauss, from 1000 Gauss to 5000 Gauss, from 2000 Gauss to 5000 Gauss, from 2000 gauss to 10000 Gauss, or from 5000 Gauss to 10000 Gauss. Useful permanent magnets include those having a residual flux density of from 10000 Gauss to 15000 Gauss, such as from 10000 Gauss to 12500 Gauss or from 12500 Gauss to 15000 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. In some embodiments, a system for making a metal product comprises a first magnetic field source positioned to expose an elongated metal substrate 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 may heat 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 some embodiments, a system for making a metal product comprises a first laser source positioned to expose an elongated metal substrate 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 may heat 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 may comprise 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, for example. 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.
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.
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 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.
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 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.
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.
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.
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 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.
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.
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).
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 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.
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.
As used herein, the meaning of “a,” “an,” and “the” includes singular and plural references unless the context clearly dictates otherwise.
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 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.
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.
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.
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.
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.
In
In
In
Although
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. 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.
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.
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.
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, CO2 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.
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.
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
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
In
Although
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.
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
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.
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
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 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.
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.
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.
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.
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.
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.
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.
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”).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Aspect 19 is the method of any previous or subsequent aspect, wherein the first laser source comprises a diode laser, a fiber laser, a CO2 laser, a YAG laser, an excimer laser, a dye laser, or an ion laser.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Aspect 42 is the system of any previous or subsequent aspect, wherein the first laser source comprises a diode laser, a fiber laser, a CO2 laser, a YAG laser, an excimer laser, a dye laser, or an ion laser.
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.
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.
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.
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.
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.
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.
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.
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.
Aspect 51 is a metal product formed using the method of any previous aspect or the system of any previous aspect.
Aspect 52 is the metal product of any previous aspect, wherein the metal product comprises an automotive structural product.
This application claims the benefit of and priority to U.S. Provisional Application No. 62/705,911, filed on Jul. 22, 2020 and U.S. Provisional Application No. 63/199,302, filed on Dec. 18, 2020, each of which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/042480 | 7/21/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62705911 | Jul 2020 | US | |
| 63199302 | Dec 2020 | US |
