KR20240039158A - Heat treated aluminum sheet and its manufacturing process - Google Patents

Abstract

Disclosed herein is a process for continuous heat treatment of metal, such as a heat treatable alloy, in which a strip of metal is solutionized and rapidly cooled, then heat spiked and coiled at an elevated temperature. The continuous heat treatment process does not include or require batch aging treatment.

Description

Heat treated aluminum sheet and its manufacturing process

Cross-reference to related applications

This application claims the benefit of U.S. Provisional Application No. 63/263,052, filed October 26, 2021, which is incorporated herein by reference in its entirety.

technology field

This disclosure relates generally to metal processing, and more specifically to continuous heat treatment processes for metals in which strips of heat treatable alloy are solutionized, rapidly cooled, thermally spiked, and coiled.

Metal article manufacturers are faced with the challenge of providing thin gauge materials that have both good formability and high strength after the article is formed and the paint cures. For example, the automotive industry needs these products for use in weight-reducing body panels or structural members to improve vehicle economy and fuel efficiency.

Heat-treatable metals, such as heat-treatable aluminum alloys, can achieve this purpose in some cases. Heat-treatable alloys are generally alloys that contain soluble alloying elements in amounts exceeding their room temperature solubility limits. These alloys may contain hardening elements (e.g., Mg, Si, and/or Co) to provide hardening during aging and potentially other elements such as Fe, Mn, and Cr to control formability and grain size. . These alloys can exhibit improved properties by processing and/or heating followed by a quenching step. Heat treatment of metals is traditionally carried out by precipitation hardening, which includes solution heat treatment and aging steps. In a solution heat treatment process, a metal strip, for example an aluminum alloy strip, is solution heat treated, rapidly cooled, and may or may not be thermally spiked depending on product requirements. The purpose of the solution heat procedure is to introduce alloying (solute) elements into solution, ultimately strengthening a particular alloy. The purpose of rapid cooling is to fix the solute elements and excess voids in the metal (e.g. aluminum) matrix of the metal strip. The purpose of heat spiking is to ensure that the coils are coiled between 60°C and 110°C and to eliminate the adverse effects of coil storage during paint baking, where the material can lose up to 40% of its strength gains. Heat-treated metal strips may undergo an aging procedure.

For example, the current process for producing aging tempers involves heating a coil of T4 temper at a rate of 20°C/h to 50°C/h to a temperature in the range of 120°C to 260°C and then It requires a batch aging process in which it is soaked for a time and then cooled to room temperature. However, conventional heat treatment and batch aging processes require total cycle times and soak times ( time (often 4 to 6 hours), added steps and complexity, and require precise control over the heat treatment process.

The term examples and similar terms are intended to broadly refer to all subject matter of this disclosure and the claims below. Statements containing these terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of the claims below. Embodiments of the disclosure covered herein are defined by the claims below and not by 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 separately to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all drawings, and each claim of this disclosure as appropriate.

Certain aspects and features of the present invention include metal strips that are solutionized, rapidly cooled, heat spiked at elevated temperatures ranging from 120°C to 300°C (e.g., 200°C to 250°C), and continuously cooled. It relates to a continuous heat treatment process with coiling at a rewinding location located at the end of the line. In some embodiments, the continuous heat treatment process and its constituent steps may occur at a particular line speed, such as at least 10 meters/minute (e.g., at least 40 meters/minute; from 10 meters/minute to 100 meters/minute). minutes, 40 meters/minute to 100 meters/minute, or 10 meters/minute to 40 meters/minute). In some embodiments, heat spike processing may occur in relatively long reheat furnaces, such as longer than 10 meters. In some embodiments, only natural cooling occurs between the heat spike and coiling (i.e., no cooling device is used) and coiling is performed in a manner that maintains line speed. In some embodiments, the cooling or natural cooling rate after heat spike treatment is less than 10°C/hour (e.g., less than 2°C/hour) to ambient temperature. Accordingly, in some embodiments, the coiling of the metal strip may be performed at a relatively warm temperature, such as above 110°C, 70°C to 150°C, 70°C to 130°C, or 70°C to 110°C, 110°C. It is carried out at temperatures above 60°C, such as from °C to 150°C, from 110°C to 130°C, or from 110°C to 120°C. In certain embodiments, the disclosed process does not include or require a batch aging process to age harden the material.

The present disclosure allows the production of products from the disclosed process with thin gauges that have both excellent formability and high strength using continuous annealing lines without the need for a batch aging process. The present disclosure is particularly advantageous by providing products with customized combinations of properties, thereby providing downgauging potential or as a potential replacement for the 5000 series aluminum alloys supplied in H1X, H2X and H3x tempers.

Certain aspects and features of the present disclosure include a metal strip being solutionized, rapidly cooled, thermally spiked (e.g., by hot air) at elevated temperatures ranging from 120°C to 300°C, and coiled; It relates to a continuous heat treatment process with cooling or natural cooling (before and/or after coiling), for example at a rate of less than 5°C/hour, preferably less than 2°C/hour. In certain embodiments, the metal strip is a heat treatable alloy, such as a heat treatable aluminum alloy.

In certain embodiments, the thermal spike temperature is maintained between 120°C and 300°C (e.g., about 150°C and 300°C). Using a thermal spike at higher temperatures can induce the formation of clusters that serve as nuclei to form hardened particles during subsequent coiling and coil cooling.

The present disclosure partially improves on existing technology by completely eliminating the batch process by using a reheater furnace to thermally spike the metal strip at line speed to the desired temperature prior to coiling. For example, a continuous annealing line can be used without a batch aging process. Heat spiked coils combined with coil cooling provide suitable conditions for age hardening. The use of thermal spiking and coiling at warm coiling temperatures to tune various properties is achieved by the present disclosure. The present disclosure is particularly advantageous in that it provides products with customized combinations of properties and thus the possibility of downgauging.

Although aspects and features of the present disclosure are described herein with respect to metal strip, such as continuously cast or uncoiled metal strip, the present disclosure may be used with any suitable metal product processed on a continuous annealing line. Aspects and features of the present disclosure may be particularly suitable for any metal product with a flat surface. Aspects and features of the present disclosure may be particularly suitable for any metal product having parallel or approximately parallel opposing surfaces (e.g., top and bottom surfaces). Approximately parallel may include parallel or parallel to within 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10° or more.

Definition and Description

As used herein, the terms “invention,” “the invention,” “such invention,” and “the present invention” are intended to refer broadly to all subject matter of this patent application and the claims below. Descriptions containing such terms should not be construed as limiting the subject matter described herein or limiting the meaning or scope of the claims below.

In this description, reference is made to alloys identified by their AA numbers and other related designations such as "series" or "7xxx". To understand the numbering systems most commonly used to name and identify aluminum and its alloys, see "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" and "Castings", both published by the Aluminum Society. and the Aluminum Association Alloy Designation and Chemical Composition Limitation Registration Records for aluminum alloys in ingot form.”

As used herein, a plate generally has a thickness greater than about 15 mm. For example, plate may mean an aluminum product having a thickness 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. You can.

As used herein, a sheet (also referred to as a sheet plate) generally has a thickness of about 4 mm to about 15 mm. For example, the sheet 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, sheet refers to an aluminum product generally having a thickness of less than about 4 mm. For example, the thickness of the sheet may be 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., less than about 0.2 mm).

As used herein, foil refers to a metal product generally having a thickness of less than about 0.2 mm. For example, the thickness of the foil may be less than about 0.2 mm, less than about 0.15 mm, less than about 0.10 mm, less than about 0.05 mm, less than about 0.04 mm, less than about 0.03 mm, less than about 0.02 mm, or less than about 0.01 mm (e.g. For example, it may be about 0.006 mm).

As used herein, direct cooling (DC) and continuous casting are two methods of casting solid metal from liquid metal. In DC casting, liquid metal is poured into a mold with a retractable false bottom that can be withdrawn at the rate of solidification of the liquid metal within the mould, often forming large, relatively thick ingots (e.g., 1500 mm wide x 1500 mm thick). 500mm x 5m length) is created. The ingots may be processed, homogenized, hot rolled, cold rolled, and may or may not be annealed after hot rolling or before passing the final cold rolling and/or prior to heat treatment, into metal strip products that may be distributed to consumers of the metal strip products. It may be finished before coiling (e.g., in an automobile manufacturing facility).

Continuous casting involves continuously injecting molten metal into a casting cavity defined between a pair of moving opposing casting surfaces and withdrawing a cast metal form (e.g. a metal strip) from the exit of the casting cavity. Continuous casting was desirable when the entire product could be manufactured on a single, fully coupled processing line. These fully coupled processing lines involve matching or “coupling” the speed of the continuous casting equipment to that of the downstream processing equipment.

In this application, reference may be made to alloy temper or condition. To understand the most commonly used alloy temper descriptions, refer to “American National Standard (ANSI) H35 for the Designation System for Alloys and Tempers.” F condition or temper refers to the manufactured aluminum alloy. O Condition or temper refers to the aluminum alloy after annealing. Hxx condition or temper, also referred to herein as H temper, refers to an aluminum alloy that is non-heat treatable after cold rolling, with or without heat treatment (e.g., annealing). Suitable H tempers include HX1, HX2, HX3 HX4, HX5, HX6, HX7, HX8 or HX9 tempers. T1 condition or temper refers to an aluminum alloy cooled from hot working and naturally aged (e.g. at room temperature). T2 condition or temper refers to aluminum alloys cooled during hot working, cold working and natural aging processes. T3 condition or temper refers to aluminum alloys that have been solution treated, cold worked and naturally aged. T4 condition or temper refers to aluminum alloy that has been solution heat treated and naturally aged. T5 condition or temper refers to aluminum alloy cooled from hot working and artificially aged (at elevated temperatures). T6 condition or temper refers to aluminum alloy that has been solution heat treated and artificially aged. T7 condition or temper refers to aluminum alloy that has been solution heat treated and artificially overaged. T8x condition or temper refers to aluminum alloy that has been solution treated, cold worked and artificially aged. T9 condition or temper refers to aluminum alloys that have been solution treated, artificially aged and cold worked. W state or temper refers to aluminum alloy after solution heat treatment.

As used herein, “room temperature” means a temperature of about 15°C to about 30°C, for example about 15°C, about 16°C, about 17°C, about 18°C, about 19°C. , approx. 20°C, approx. 21°C, approx. 22°C, approx. 23°C, approx. 24°C, approx. 25°C, approx. 26°C, approx. 27°C, approx. 28°C, approx. 29°C , or about 30°C. As used herein, the meaning of "ambient conditions" or "ambient environment" may include a temperature of about room temperature, a relative humidity of about 20% to about 100%, and an atmospheric pressure of about 975 millibars (mbar) to about 1050 mbar. . For example, relative humidity is 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 It may be 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 100%, or any value in between. For example, atmospheric pressure is 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. mbar, about 1045 mbar, It may be around 1050 mbar, or any value in between.

All ranges disclosed herein are to be understood to include any and all subranges subsumed therein. For example, a stated range of "1 to 10" should be considered to include all subranges between (inclusive) the minimum value of 1 and the maximum value of 10; That is, all subranges starting with a minimum value greater than or equal to 1, for example 1 to 6.1, and all subranges ending with a maximum value less than or equal to 10, for example 5.5 to 10. Unless otherwise specified, the expression "maximum" when referring to the composition of an element means that the element is optional and that the composition of that particular element is 0%. Unless otherwise specified, all composition percentages are in weight percent (wt.%).

As used herein, the singular terms “a”, “an” and “the” include singular and plural references, unless the context clearly dictates otherwise.

In this description, aluminum alloy products and their components may be described in terms of elemental composition in weight percent (wt.%). The remainder in each alloy is aluminum, with a maximum wt.% of 0.15% for the sum of all impurities.

Additional elements or other additives, such as grain refiners and deoxidizers, may be present in the invention and may by themselves add other properties without departing from or significantly altering the properties of the alloys described herein or the alloys described herein. You can.

metal strip

As discussed, the heat treatment process of the present disclosure can be performed on a metal strip, such as an aluminum alloy strip. In certain embodiments, the metal strips described herein may be produced from metal casting, such as DC casting or metal continuous casting. After casting, in certain embodiments, homogenization, hot rolling and/or cold rolling, and optional annealing may be performed after hot rolling or before final cold rolling to produce the metal strip.

In certain aspects, the metal strip may be a metal sheet, sheet, or foil. In certain aspects, the metal strip can be a sheet. For example, in one embodiment, the described process is used to produce sheets with gauges from 0.5 mm to 4.5 mm. In some such embodiments, the metal strip may be an aluminum alloy sheet, for example a heat treatable aluminum alloy sheet. In some aspects, the metal strip may be selected from 2xxx series, 6xxx series, or 7xxx series aluminum alloy sheets. In some embodiments, the metal strip is a 2xxx series aluminum alloy sheet. In some embodiments, the metal strip is a 6xxx series aluminum alloy sheet. In some embodiments, the metal strip is a 7xxx series aluminum alloy sheet. In certain aspects, the metal strip can be a sheet. In some aspects, the metal strip may be an aluminum alloy sheet, such as a heat treatable aluminum alloy sheet. In some aspects, the metal strip may be selected from 2xxx series, 6xxx series, or 7xxx series aluminum alloy sheets. In some embodiments, the metal strip is a 2xxx series aluminum alloy sheet. In some embodiments, the metal strip is a 6xxx series aluminum alloy sheet. In some embodiments, the metal strip is a 7xxx series aluminum alloy sheet. In certain aspects, the metal strip can be a foil. In some aspects, the metal strip may be an aluminum alloy foil, such as a heat treatable aluminum alloy foil. In some aspects, the metal strip may be selected from 2xxx series, 6xxx series, or 7xxx series aluminum alloy foil. In some embodiments, the metal strip is a 2xxx series aluminum alloy foil. In some embodiments, the metal strip is a 6xxx series aluminum alloy foil. In some embodiments, the metal strip is a 7xxx series aluminum alloy foil.

In certain embodiments, the alloy exhibits high strength and high deformability. In some cases, the strength of the alloy may increase after heat treatment without significant loss of deformability. The properties of the alloy are achieved at least in part due to the method of processing the alloy to produce the described foil, sheet, sheet or other product.

In some embodiments, the alloy may have the following elemental composition as provided in Table 1.

In some examples, the alloy may have the following elemental composition as provided in Table 2.

In another example, the alloy may have the following elemental composition as provided in Table 3.

In one example, the aluminum alloy may have the following elemental composition as provided in Table 4. In certain embodiments, the alloy is used to make aluminum foil and sheet.

In certain embodiments, the disclosed alloy has an amount of about 0.05% to about 1.2% (e.g., about 0.1% to about 1.2%, about 0.2% to about 1.1%, about 0.3% to about 1.0%) based on the total weight of the alloy. , about 0.4% to about 1.0%, about 0.6% to about 1.1%, about 0.65% to about 0.9%, about 0.7% to about 1.0%, or about 0.6% to about 0.7%). Includes. For example, the alloy may have about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, About 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28 %, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34%, about 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.39%, about 0.4%, About 0.41%, about 0.42%, about 0.43%, about 0.44%, about 0.45%, about 0.46%, about 0.47%, about 0.48%, about 0.49%, about 0.5%, about 0.51%, about 0.52%, about 0.53 %, about 0.54%, about 0.55%, about 0.56%, about 0.57%, about 0.58%, about 0.59%, about 0.6%, about 0.61%, about 0.62%, about 0.63%, about 0.64%, about 0.65%, About 0.66%, about 0.67%, about 0.68%, about 0.69%, about 0.7%, about 0.71%, about 0.72%, about 0.73%, about 0.74%, about 0.75%, about 0.76%, about 0.77%, about 0.78 %, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83%, about 0.84%, about 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89%, about 0.9%, About 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, about 0.96%, about 0.97%, about 0.98%, about 0.99%, about 1.0%, about 1.01%, about 1.02%, about 1.03 %, about 1.04%, about 1.05%, about 1.06%, about 1.07%, about 1.08%, about 1.09%, or about 1.1% Cu. All wt. It is expressed in %.

In certain embodiments, the disclosed alloys have about 0.6% to about 1.5% (e.g., about 0.7% to about 1.3%, about 0.8% to about 1.2%, about 0.9% to about 1.1%) based on the total weight of the alloy. , about 0.6% to about 0.9%, about 0.9% to about 1.1%, or about 1.0% to about 1.1%). For example, the alloy may have about 0.6%, about 0.61%, about 0.62%, about 0.63%, about 0.64%, about 0.65%, about 0.66%, about 0.67%, about 0.68%, about 0.69%, about 0.7%, About 0.71%, about 0.72%, about 0.73%, about 0.74%, about 0.75%, about 0.76%, about 0.77%, about 0.78%, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83 %, about 0.84%, about 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89%, about 0.9%, about 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, About 0.96%, about 0.97%, about 0.98%, about 0.99%, about 1.0%, about 1.01%, about 1.02%, about 1.03%, about 1.04%, about 1.05%, about 1.06%, about 1.07%, about 1.08 %, about 1.09%, or about 1.1% Si. All wt. It is expressed in %.

In certain embodiments, the disclosed alloy has about 0.3% to about 1.3% (e.g., about 0.4% to about 1.25%, about 0.5% to about 1.2%, about 0.7% to about 1.1%) based on the total weight of the alloy. , about 0.8% to about 1.25%, about 1.1% to about 1.25%, about 1.1% to about 1.2%, about 1.0% to about 1.2%, about 1.05% to about 1.3%, or about 1.15% to about 1.3%) Contains magnesium (Mg) in an amount of For example, the alloy may have about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.71%, about 0.72%, about 0.73%, about 0.74%, about 0.75%, about 0.76%, About 0.77%, about 0.78%, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83%, about 0.84%, about 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89 %, about 0.9%, about 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, about 0.96%, about 0.97%, about 0.98%, about 0.99%, about 1.0%, about 1.01%, About 1.02%, about 1.03%, about 1.04%, about 1.05%, about 1.06%, about 1.07%, about 1.08%, about 1.09%, about 1.1%, about 1.11%, about 1.12%, about 1.13%, about 1.14 %, about 1.15%, about 1.16%, about 1.17%, about 1.18%, about 1.19%, or about 1.2% Mg. All wt. It is expressed in %.

In certain embodiments, the alloy has up to about 0.25% (e.g., about 0% to about 0.25%, about 0.03% to about 0.06%, about 0.03% to about 0.19%, or about 0.06%) based on the total weight of the alloy. and about 0.1%) of chromium (Cr). For example, the alloy may have about 0.001%, about 0.002%, about 0.003%, about 0.004%, about 0.005%, about 0.006%, about 0.007%, about 0.008%, about 0.059%, about 0.01%, about 0.011%, About 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017%, about 0.018%, about 0.019%, about 0.02%, about 0.021%, about 0.022%, about 0.023%, about 0.024 %, about 0.025%, about 0.026%, about 0.027%, about 0.028%, about 0.029%, about 0.03%, about 0.031%, about 0.032%, about 0.033%, about 0.034%, about 0.035%, about 0.036%, About 0.037%, about 0.038%, about 0.039%, about 0.04%, about 0.041%, about 0.042%, about 0.043%, about 0.044%, about 0.045%, about 0.046%, about 0.047%, about 0.048%, about 0.049 %, about 0.05%, about 0.051%, about 0.052%, about 0.053%, about 0.054%, about 0.055%, about 0.056%, about 0.057%, about 0.058%, about 0.059%, about 0.06%, about 0.061%, About 0.062%, about 0.063%, about 0.064%, about 0.065%, about 0.066%, about 0.067%, about 0.068%, about 0.069%, about 0.07%, about 0.071%, about 0.072%, about 0.073%, about 0.074 %, about 0.075%, about 0.076%, about 0.077%, about 0.078%, about 0.079%, about 0.08%, about 0.081%, about 0.082%, about 0.083%, about 0.084%, about 0.085%, about 0.086%, About 0.087%, about 0.088%, about 0.089%, about 0.09%, about 0.091%, about 0.092%, about 0.093%, about 0.094%, about 0.095%, about 0.096%, about 0.097%, about 0.098%, about 0.099 %, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, It may contain about 0.22%, about 0.23%, about 0.24%, or about 0.25% Cr. All wt. It is expressed in %. In some cases, Cr is not present in the alloy (i.e., 0%). In some instances, Cr can control grain structure and prevent grain growth and recrystallization. Higher Cr content can provide higher formability and improved bendability in aged temper.

In certain examples, the alloy may have up to about 0.35% (e.g., about 0% to about 0.35%, about 0.05% to about 0.18%, about 0.1% to about 0.35%, or about 0.1%), based on the total weight of the alloy. It may contain manganese (Mn) in an amount of from about 0.3%). For example, the alloy may have about 0.001%, about 0.002%, about 0.003%, about 0.004%, about 0.005%, about 0.006%, about 0.007%, about 0.008%, about 0.059%, about 0.01%, about 0.011%, About 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017%, about 0.018%, about 0.019%, about 0.02%, about 0.021%, about 0.022%, about 0.023%, about 0.024 %, about 0.025%, about 0.026%, about 0.027%, about 0.028%, about 0.029%, about 0.03%, about 0.031%, about 0.032%, about 0.033%, about 0.034%, about 0.035%, about 0.036%, About 0.037%, about 0.038%, about 0.039%, about 0.04%, about 0.041%, about 0.042%, about 0.043%, about 0.044%, about 0.045%, about 0.046%, about 0.047%, about 0.048%, about 0.049 %, about 0.05%, about 0.051%, about 0.052%, about 0.053%, about 0.054%, about 0.055%, about 0.056%, about 0.057%, about 0.058%, about 0.059%, about 0.06%, about 0.061%, About 0.062%, about 0.063%, about 0.064%, about 0.065%, about 0.066%, about 0.067%, about 0.068%, about 0.069%, about 0.07%, about 0.071%, about 0.072%, about 0.073%, about 0.074 %, about 0.075%, about 0.076%, about 0.077%, about 0.078%, about 0.079%, about 0.08%, about 0.081%, about 0.082%, about 0.083%, about 0.084%, about 0.085%, about 0.086%, About 0.087%, about 0.088%, about 0.089%, about 0.09%, about 0.091%, about 0.092%, about 0.093%, about 0.094%, about 0.095%, about 0.096%, about 0.097%, about 0.098%, about 0.099 %, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, About 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34 %, or about 0.35% Mn. In some cases, Mn is not present in the alloy (i.e., 0%). All wt. It is expressed as %.

In certain embodiments, the alloy may also contain about 0.1% to about 0.35% (e.g., about 0.1% to about 0.3%, about 0.1% to about 0.25%, about 0.18% to about 0.25%, and iron (Fe) in an amount of about 0.2% to about 0.21%, or about 0.15% to about 0.22%). For example, the alloy may have about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, It may contain about 0.21%, about 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, or about 0.30 Fe. In some cases, Fe is not present in the alloy (i.e., 0%). All wt. It is expressed in %.

In certain embodiments, the alloy has up to about 0.25% (e.g., about 0% to about 0.2%, about 0.01% to about 0.25%, about 0.01% to about 0.15%, about 0.01% to about 0.01%), based on the total weight of the alloy. and zirconium (Zr) in an amount of about 0.1%, or about 0.02% to about 0.09%). For example, the alloy may have about 0.001%, about 0.002%, about 0.003%, about 0.004%, about 0.005%, about 0.006%, about 0.007%, about 0.008%, about 0.009%, about 0.01%, about 0.02%, About 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15 %, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, or about 0.25% Zr. In certain embodiments, Zr is not present in the alloy (i.e., 0%). All wt. It is expressed in %. In some instances, Zr can control crystal structure and prevent crystal growth and recrystallization. Higher amounts of Zr can provide higher formability and improved bendability even in T4 and aged tempers.

In certain embodiments, the alloys described herein have up to about 1.0% (e.g., about 0% to about 1.0%, about 0.001% to about 0.3%, about 0.005% to about 0.09%) based on the total weight of the alloy. , from about 0.004% to about 0.3%, from about 0.03% to about 0.2%, or from about 0.06% to about 0.1%). For example, the alloy may have about 0.001%, about 0.002%, about 0.003%, about 0.004%, about 0.005%, about 0.006%, about 0.007%, about 0.008%, about 0.009%, about 0.01%, about 0.011%, About 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017%, about 0.018%, about 0.019%, about 0.02%, about 0.021%, about 0.022%, about 0.023%, about 0.024 %, about 0.025%, about 0.026%, about 0.027%, about 0.028%, about 0.029%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, About 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.2%, about 0.21%, about 0.22 %, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, about 0.3%, about 0.31%, about 0.32%, about 0.33%, about 0.34%, About 0.35%, about 0.36%, about 0.37%, about 0.38%, about 0.39%, about 0.4%, about 0.41%, about 0.42%, about 0.43%, about 0.44%, about 0.45%, about 0.46%, about 0.47 %, about 0.48%, about 0.49%, about 0.50%, about 0.51%, about 0.52%, about 0.53%, about 0.54%, about 0.55%, about 0.56%, about 0.57%, about 0.58%, about 0.59%, About 0.6%, about 0.61%, about 0.62%, about 0.63%, about 0.64%, about 0.65%, about 0.66%, about 0.67%, about 0.68%, about 0.69%, about 0.7%, about 0.71%, about 0.72 %, about 0.73%, about 0.74%, about 0.75%, about 0.76%, about 0.77%, about 0.78%, about 0.79%, about 0.8%, about 0.81%, about 0.82%, about 0.83%, about 0.84%, About 0.85%, about 0.86%, about 0.87%, about 0.88%, about 0.89%, about 0.90%, about 0.91%, about 0.92%, about 0.93%, about 0.94%, about 0.95%, about 0.96%, about 0.97 %, about 0.98%, about 0.99%, or about 1.0% Zn. In some cases, Zn is not present in the alloy (i.e., 0%). All wt. It is expressed in %. In certain embodiments, Zn may provide forming benefits, including reducing bending and bending anisotropy of foil, sheet and sheet products.

In certain aspects, the alloy has up to about 0.3% (e.g., about 0% to about 0.3%, about 0.01% to about 0.25%, about 0.05% to about 0.2%, or up to about 0.1%), based on the total weight of the alloy. %) and contains titanium (Ti). For example, the alloy has about 0.01%, about 0.011%, about 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017%, about 0.018%, about 0.019%, about 0.02%. , about 0.025%, about 0.03%, about 0.035%, about 0.04%, about 0.045%, about 0.05%, about 0.055%, 0.06%, about 0.065%, about 0.07%, about 0.075%, about 0.08%, about 0.085 %, about 0.09%, about 0.095%, about 0.1%, about 0.11%, about 0.12%, about 0.13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, It may contain about 0.2%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, about 0.25%, about 0.26%, about 0.27%, about 0.28%, about 0.29%, or about 0.3% Ti. there is. In certain embodiments, Ti is not present in the alloy (i.e., 0%). All wt. It is expressed in %.

In certain embodiments, the alloy contains nickel (e.g., nickel) in an amount of up to about 0.04% (e.g., 0% to about 0.02%, about 0.01% to about 0.03%, about 0.03% to about 0.04%) based on the total weight of the alloy. Includes Ni). For example, the alloy may have about 0.001%, about 0.005%, about 0.01%, about 0.011%, about 0.012%, about 0.013%, about 0.014%, about 0.015%, about 0.016%, about 0.017%, about 0.018%, About 0.019%, about 0.02%, about 0.021%, about 0.022%, about 0.023%, about 0.024%, about 0.025%, about 0.026%, about 0.027%, about 0.028%, about 0.029%, about 0.03%, about 0.031 %, about 0.032%, about 0.033%, about 0.034%, about 0.035%, about 0.036%, about 0.037%, about 0.038%, about 0.039%, or about 0.04% Ni. In certain embodiments, Ni is not present in the alloy (i.e., 0%). All wt. It is expressed in %.

Optionally, the alloy composition may further include other trace elements, sometimes referred to as impurities, in amounts of up to about 0.05%, up to about 0.04%, up to about 0.03%, up to about 0.02%, or up to about 0.01%, respectively. . These impurities may include, but are not limited to, V, Ga, Ca, Hf, Sr, Sc, Sn, or combinations thereof. Accordingly, V, Ga, Ca, Hf, Sr, Sc, Sn may be present in the alloy in an amount of about 0.05% or less, about 0.04% or less, about 0.03% or less, about 0.02% or less, or about 0.01% or less. In certain embodiments, the sum of all impurities does not exceed about 0.15% (e.g., 0.1%). All wt. It is expressed in %. In certain embodiments, the remaining percentage of the alloy is aluminum.

Continuous heat treatment process

Certain aspects and features of the present invention include continuous thermal processing in which a metal strip is solutionized, rapidly cooled, and then thermally spiked and coiled at elevated temperatures (e.g., temperatures ranging from 120°C to 300°C), as described below. It is about the treatment process. In certain embodiments, the metal strip is a heat treatable alloy, such as a heat treatable aluminum alloy. In certain embodiments, the heat spiked metal strip is cooled before or after coiling. In certain embodiments, the heat spiked metal strip is only cooled naturally before or after coiling. In some embodiments, the coil may be cooled after coiling (e.g., using cooling fan(s)) at the end of a continuous heat treatment process. In certain embodiments, the metal strip itself may be manufactured from scalping, homogenizing, hot rolling, optionally batch annealing, and cold rolling of cast ingots.

Continuous heat treatment processes can be operated at specific line speeds. For example, a continuous heat treatment process may be used at speeds greater than 5 meters/minute, such as greater than 10 meters/minute, greater than 20 meters/minute, greater than 25 meters/minute, greater than 30 meters/minute, greater than 40 meters/minute, greater than 50 meters/minute. meters/minute or more, 60 meters/minute or more, 70 meters/minute or more, 80 meters/minute or more, 90 meters/minute or more, 100 meters/minute or more, 10 meters/minute to 100 meters/minute, 20 meters/minute or more It can be operated at line speeds of 80 meters/minute, 30 meters/minute to 70 meters/minute, or 40 meters/minute to 60 meters/minute.

solution

Solution heating can place the desired amount of alloying elements present in a particular alloy into solution (e.g., aluminum solid solution). In some embodiments, the solutionizing step is to heat the metal strip (e.g., plate, sheet, sheet, or foil) from room temperature to about 400°C to about 590°C (e.g., from about 450°C to about 575°C). , about 400°C to about 525°C, about 450°C to about 510°C, about 520°C to about 590°C, about 520°C to about 580°C, about 520°C to about 560°C. , about 530°C to about 570°C, about 545°C to about 575°C, about 550°C to about 570°C, about 555°C to about 565°C, about 540°C to about 560°C. , about 540°C to about 575°C, about 560°C to about 580°C, about 550°C to about 575°C, about 540°C, about 550°C, about 560°C, or about 570° It may include heating to a temperature of C).

In certain embodiments, the strip may be immersed at the temperature for a period of time. In certain embodiments, brief soaking of the strip is permitted (e.g., up to about 5 minutes, about 10 seconds to about 5 minutes, about 1 second to about 3 minutes, or about 5 seconds to about 5 minutes). For example, strips may be less than 20 seconds, less than 25 seconds, less than 30 seconds, less than 35 seconds, less than 40 seconds, less than 45 seconds, less than 50 seconds, less than 55 seconds, less than 60 seconds, less than 65 seconds, less than 70 seconds, Less than 75 seconds, less than 80 seconds, less than 85 seconds, less than 90 seconds, less than 95 seconds, less than 100 seconds, less than 105 seconds, less than 110 seconds, less than 115 seconds, less than 120 seconds, less than 125 seconds, less than 130 seconds, less than 135 seconds The immersion may be at the temperature (e.g., from about 525°C to about 590°C) for less than, less than 140 seconds, less than 145 seconds, less than 150 seconds, or less than 5 minutes, or any value in between.

In certain embodiments, solutionizing can be performed in a continuous process, for example in a continuous heat treatment line. In some embodiments, a continuous process (e.g., a continuous heat treatment line) may have a specific line speed.

In certain embodiments, the solutionizing step is performed on the metal strip immediately after the hot rolling step and/or the cold rolling step. In another aspect, the solutionizing step is performed on the metal strip after the hot rolling step and/or the cold rolling step (e.g., >48 hours later). In certain embodiments, the solutionizing step is performed after the annealing and cold rolling steps.

rapid cooling

Without being bound by theory, the metal strip can be cooled very rapidly to lock the solute elements and excess pores into the metal (e.g. aluminum) matrix of the metal strip. Accordingly, in some embodiments, after solutionizing, the metal strip may be rapidly cooled to lower the temperature of the metal strip. In some embodiments, the transfer time from the solution furnace to the cooling medium is very short (e.g., less than 1 second, less than 2 seconds, less than 3 seconds, less than 5 seconds, less than 10 seconds, less than 15 seconds, less than 20 seconds, 25 seconds). Less than 2 seconds, less than 30 seconds, less than 35 seconds, less than 40 seconds, less than 45 seconds, less than 50 seconds, less than 55 seconds, less than 1 minute, less than 2 minutes, less than 3 minutes, less than 4 minutes, less than 5 minutes, less than 10 minutes ). The time during which the solutionized metal is transported begins from the moment the furnace door begins to open and progresses to the point where the aluminum alloy is completely submerged and submerged. If the transfer time exceeds the specified time limit, incomplete solutionization may occur, which means that the metallurgical and mechanical conditions of the particular alloy are non-uniform.

In certain embodiments, after solutionizing, the metal strip may be cooled in a rapid cooling step based on the selected gauge at a rate that can vary between about 1°C/s and 400°C/s. For example, the rapid cooling rate may be from about 50°C/s to about 375°C/s, from about 60°C/s to about 375°C/s, from about 70°C/s to about 350°C/s, From about 80°C/s to about 325°C/s, from about 90°C/s to about 300°C/s, from about 100°C/s to about 275°C/s, from about 125°C/s to about 250°C/s, about 150°C/s to about 225°C/s, about 175°C/s to about 200°C/s, about 10°C/s to about 125°C/s, or about It can be from 20°C/s to about 125°C/s. In some embodiments, the metal strip is heated below 100°C, e.g., below 90°C, below 80°C, below 70°C, below 60°C, below 50°C, below 45°C, below 40°C. , below 35°C, below 30°C, below 25°C, below 20°C, below 15°C, about 20°C to about 80°C, about 20°C to about 70°C, about 20°C to about 60°C, about 25°C to about 50°C, about 25°C to about 40°C, up to about 20°C, up to about 25°C, up to about 30°C, up to about 35°C, It can be rapidly cooled to temperatures up to about 40°C, about 45°C, or about 50°C.

In certain embodiments, the metal strip can be rapidly cooled using liquid (e.g., water) and/or gas or other selected cooling medium. In certain embodiments, the metal strip is rapidly cooled with air. In certain embodiments, the metal strip can be rapidly cooled with water.

thermal spike

Metal strips can be subjected to heat spikes at elevated temperatures. As described herein, using higher thermal spike temperatures than previously disclosed in the art has helped achieve the unexpected benefits of the present disclosure. In some embodiments, the thermal spike temperature (i.e., the highest temperature to which the metal strip is exposed, but not necessarily the temperature of the metal strip itself) ranges from about 100°C to about 300°C, e.g., from about 120°C to About 300°C, about 150°C to about 300°C, about 170°C to about 280°C, about 180°C to about 270°C, about 190°C to about 260°C, about 200°C to about 250°C, about 210°C to about 250°C, about 220°C to about 250°C, about 220°C to about 240°C, about 200°C, about 210°C, about 220° C, may be about 230°C, about 240°C, or about 250°C. In some embodiments, the metal strip itself is within 100°C of the thermal spike temperature, e.g., within 90°C, within 80°C, within 70°C, within 60°C, within 50°C, within 40°C. , reach within 30°C, within 20°C, within 10°C, within 5°C, within 1°C.

In some embodiments, heat spiking occurs after solutionizing and air cooling the metal strip. In some embodiments, heat spike processing may occur at the same processing line speed as solutionizing and flash cooling, for example, as part of a continuous heat treatment process.

Conventional 6XXX material in T4 or T4P temper contains a large number of microscopic metastable clusters and zones evenly distributed throughout the metal matrix. In conventional processes, during paint curing, some microscopic unstable clusters/zones dissolve back into the metal matrix while others improve the material strength due to age hardening. The process described herein allows the alloy material to exhibit an improved aging response (hardness response). Without being bound by theory, a heat spike between 150 and 320°C (e.g., in a long reheat furnace), for example between about 150 and 300°C, between about 180 and 300°C, or between about 150 and 225°C. It is believed that coiling and coil cooling forms some clusters and zones and enhances the precipitation process during coil cooling.

The period of time during which the temperature remains at the peak heat spike temperature can vary from zero to any time practical depending on the situation. In some embodiments, heat spike processing occurs at processing line speed (e.g., in a long furnace) in a continuous heat treatment process. For example, the processing line speed and heat spike processing speed may range from about 1 meter/minute to about 120 meters/minute, such as from about 2 meters/minute to about 110 meters/minute, for example, from about 5 meters/minute to about 100 meters/minute. meters/minute, from about 10 meters/minute to about 600 meters/minute, from about 20 meters/minute to about 500 meters/minute, from about 25 meters/minute to about 500 meters/minute, from about 30 meters/minute to about 400 meters/minute. minutes, from about 40 meters/minute to about 350 meters/minute, from about 50 meters/minute to about 300 meters/minute, or from about 100 meters/minute to about 250 meters/minute. In practice, this period is usually on the order of 0 minutes up to 5 minutes, for example, about 1 second to about 5 minutes, about 2 seconds to about 4 minutes, about 3 seconds to about 3 minutes, about 5 seconds to about 2 minutes, About 7 seconds to about 1 minute, or about 10 seconds to about 30 seconds.

In some embodiments, the heat spiking process is performed at a heating rate of about 1°C/min to about 50°C/s (i.e., the temperature of the metal strip increases at a constant rate, e.g., about 1°C /s to about 40°C/s, about 2°C/s to about 40°C/s, about 3°C/s to about 35°C/s, about 3°C/s to about 30°C/s. s, from about 5°C/s to about 30°C/s, from about 10°C/s to about 25°C/s, or from about 2°C/s to about 10°C/s).

In some embodiments, the heat spike treatment is performed in a reheat furnace, such as a continuous reheat furnace. In some embodiments, the heat spike treatment is performed in a long reheat furnace. For example, the oar is at least 10 meters, at least 20 meters, at least 25 meters, at least 30 meters, at least 40 meters, at least 50 meters, at least 60 meters, at least 70 meters, at least 80 meters, at least 90 meters, at least 100 meters. It can have an effective length (i.e. the length over which the metal strip is heated in a continuous process) of meters. Without limiting the present disclosure, this may allow for increased line speed and/or thermal spike time.

prescription

In some embodiments, the metal strip does not undergo an aging process. In some embodiments, thermal spiking of the metal strip combined with coiling of the metal strip and/or cooling of the metal strip can replace age hardening.

Cooling

In some aspects, the metal strip may be cooled after heat spiking. In some embodiments, this cooling may occur after coiling. In other aspects, this cooling may occur prior to coiling. And in some aspects, cooling may occur before and/or after coiling. For example, in some aspects, the metal strip may be air cooled, for example using at least one fan. In some embodiments, the metal strip is cooled only naturally (e.g., during the passage of the strip between heat spiking and coiling), meaning that no device or process is used to cool the metal strip prior to coiling. . For example, the metal strip may only be exposed to ambient conditions (e.g., at line speed in a continuous heat treatment process) prior to coiling. In some embodiments, the metal strip cools naturally only after coiling. As described herein, natural cooling (e.g., only exposure to ambient conditions prior to cooling) does not fall within the terms "cooling" or "cooled" as previously used in the art. No. In some aspects, cooling or natural cooling may be performed until the metal strip reaches ambient temperature.

In some embodiments, the metal strip and/or coiled metal strip may be cooled or naturally cooled at a rate of less than or equal to about 60°C/hour (e.g., less than or equal to about 50°C/hour, or less than or equal to about 40°C/hour). hour or less, approximately 30°C/hour or less, approximately 20°C/hour or less, approximately 10°C/hour or less, approximately 5°C/hour or less, approximately 3°C/hour or less, approximately 2.5°C/hour or less , approximately 2°C/hour or less, approximately 1.5°C/hour or less, approximately 1°C/hour or less, or approximately 0.8°C/hour or less).

Manufacturing method of metal strip

In certain embodiments, the disclosed metal (e.g., alloy) strip compositions are the product of the disclosed methods. Without limiting the present disclosure, alloy properties, such as aluminum alloy properties, are determined in part by the formation of the microstructure during alloy manufacturing. In certain aspects, the method of making an alloy composition can influence or even determine whether the alloy will have properties suitable for the desired application.

The metal (e.g., alloy) strips described herein can be cast into ingots using casting methods. For example, the casting process may include a direct cooling (DC) casting process. In another example, the casting process may include a continuous casting process. The cast ingot may undergo additional processing steps. In one non-limiting example, the processing method includes scalping, homogenizing, hot rolling, selective batch annealing and cold rolling, rapid cooling, heat spiking, and coiling prior to the aforementioned solutionizing and subsequent cooling (e.g., coiling). After cooling with a fan).

Homogenization

In some embodiments, the homogenization step may include one-stage homogenization or two-stage homogenization. In one example of a homogenization step, an ingot made from an alloy composition described herein is heated to about or at least about 500°C (e.g., at least 520°C, at least 530°C, at least 540°C, at least 550°C). A one-step homogenization is performed to achieve a peak metal temperature (PMT) of at least 560°C, at least 570°C or at least 580°C. For example, the ingot may be heated between about 520°C and about 580°C, between about 530°C and about 575°C, between about 535°C and about 570°C, between about 540°C and about 565°C, and between about 545°C. It can be heated to a temperature of from about 560°C, from about 530°C to about 560°C, or from about 550°C to about 580°C. In some cases, the heating rate to the peak metal temperature is about 100°C/hour or less, 75°C/hour or less, 50°C/hour or less, 40°C/hour or less, 30°C/hour or less, or 25°C/hour or less. It may be below 10°C/hour, below 20°C/hour, below 15°C/hour, or below 10°C/hour. In other cases, the heating rate to the peak metal temperature may be from about 10°C/min to about 100°C/min (e.g., from about 10°C/min to about 90°C/min, about 10°C/min). min to about 70°C/min, about 10°C/min to about 60°C/min, about 20°C/min to about 90°C/min, about 30°C/min to about 80°C/min. , about 40°C/min to about 70°C/min, or about 50°C/min to about 60°C/min).

The ingot is then allowed to soak for a period of time (i.e. maintained at the indicated temperature). According to one non-limiting example, the ingot is permitted to be immersed for up to about 8 hours (e.g., including from about 5 seconds to 8 hours, or from about 30 minutes to about 8 hours). For example, the ingot may be soaked at a temperature of at least 500°C for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or any value in between. there is.

In another example of a homogenization step, a two-step homogenization is performed in which an ingot made from the alloy composition described herein is heated to achieve a first temperature of about or at least about 480°C to about 520°C. For example, the ingot may be heated to a first temperature of about 480°C, 490°C, 500°C, 510°C, or 520°C. In certain embodiments, the rate of heating to the first temperature is from about 10°C/min to about 100°C/min (e.g., from about 10°C/min to about 90°C/min, about 10°C/min) to about 70°C/min, from about 10°C/min to about 60°C/min, from about 20°C/min to about 90°C/min, from about 30°C/min to about 80°C/min, about 40°C/min to about 70°C/min, or about 50°C/min to about 60°C/min). In another aspect, the rate of heating to the first temperature is from about 10°C/hour to about 100°C/hour (e.g., from about 10°C/hour to about 90°C/hour, about 10°C/hour) to about 70°C/hour, from about 10°C/hour to about 60°C/hour, from about 20°C/hour to about 90°C/hour, from about 30°C/hour to about 80°C/hour, about 40°C/hour to about 70°C/hour, or about 50°C/hour to about 60°C/hour).

The ingot is then allowed to soak for a period of time. In some cases, the ingots are allowed to soak for up to about 6 hours (e.g., 5 seconds to 6 hours, or 30 minutes to 6 hours). For example, the ingot may be soaked at a temperature of about 480°C to about 520°C for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any time in between. there is.

In the second step of the two-step homogenization process, the ingot is heated at a first temperature greater than about 520°C (e.g., greater than 520°C, greater than 530°C, greater than 540°C, greater than 550°C, 560°C). greater than 570°C or greater than 580°C). For example, the ingot may be heated between about 520°C and about 580°C, between about 530°C and about 575°C, between about 535°C and about 570°C, between about 540°C and about 565°C, and between about 545°C. It can be heated to a second temperature of from about 560°C to about 560°C, from about 530°C to about 560°C, or from about 550°C to about 580°C. The heating rate to the second temperature is about 10°C/min to about 100°C/min (e.g., about 20°C/min to about 90°C/min, about 30°C/min to about 80°C) C/min, about 10°C/min to about 90°C/min, about 10°C/min to about 70°C/min, about 10°C/min to about 60°C/min, about 40°C /min to about 70°C/min, or about 50°C/min to about 60°C/min).

In another aspect, the rate of heating to the second temperature is from about 10°C/hour to about 100°C/hour (e.g., from about 10°C/hour to about 90°C/hour, about 10°C/hour) to about 70°C/hour, from about 10°C/hour to about 60°C/hour, from about 20°C/hour to about 90°C/hour, from about 30°C/hour to about 80°C/hour, about 40°C/hour to about 70°C/hour, or about 50°C/hour to about 60°C/hour).

The ingot is then allowed to soak for a period of time. In some cases, the ingots are allowed to soak for up to about 6 hours (e.g., 5 seconds to 6 hours, or 30 minutes to 6 hours). For example, the ingot may be soaked at a temperature of about 520°C to about 580°C for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any time in between. .

hot rolling

In some embodiments, a hot rolling step may be performed after the homogenization step. In some cases, the ingot is placed and hot rolled at an entry temperature ranging from about 380°C to about 540°C. For example, the entry temperature may be about 505°C, 510°C, 515°C, 520°C, 525°C, 530°C, 535°C, or 540°C, for example. In certain cases, the hot roll outlet temperature may range from about 230°C to about 420°C (e.g., from about 330°C to about 370°C). For example, the hot roll exit temperature is approximately 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, 355°C, 360°C, 365° C, 370°C, 375°C or 380°C and may be combined with any of the above entry temperatures.

In some cases, the ingot may be hot rolled to a thickness gauge of about 2 mm to about 15 mm (e.g., a gauge of about 5 mm to about 12 mm thick), referred to as a sheet. For example, an ingot may have about 4 mm thick gauge, about 5 mm thick gauge, about 6 mm thick gauge, about 7 mm thick gauge, about 8 mm thick gauge, about 9 mm thick gauge, about 10 mm thick gauge, about 11 mm thick gauge, about 12 mm thick gauge. It can be hot rolled to gauge, about 13 mm thick gauge, about 14 mm thick gauge, or about 15 mm thick gauge. In some cases the ingots may be hot rolled into gauges (i.e. plates) greater than 15 mm thick. In other cases, the ingot may be hot rolled to a gauge (i.e., sheet) of less than 4 mm. Hot rolled coils may in some aspects be batch annealed prior to cold rolling. In certain embodiments, it is also possible for annealing to be performed after the first cold pass or the second cold pass, but before the final cold pass.

cold rolled

In some embodiments, the cold rolling step may be performed after the hot rolling step. In certain embodiments, the rolled product from the hot rolling step may be cold rolled into sheets (e.g., less than approximately 4.0 mm). In certain embodiments, the rolled product is cold rolled to a thickness of 0.6 mm to 1.0 mm, 1.0 mm to 3.0 mm, or 3.0 mm to 4.0 mm. In certain embodiments, the alloy is cold rolled to about 3.5 mm or less, 3 mm or less, 2.5 mm or less, 2 mm or less, 1.5 mm or less, or 1 mm or less. For example, rolled products are about 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, Can be cold rolled to 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm or 3.0mm.

Aspects of the above process may be used to produce metal strips as described. Additionally, as discussed, metal strips can be processed using the disclosed continuous heat treatment process to produce heat treated articles. In some embodiments, the entire process of producing the metal strip and heat treating the metal strip is continuous. The described heat treatment process can then be applied to the metal strip.

example

These illustrative examples are provided to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings where like numbers represent like elements, and directional descriptions are used to describe example embodiments but, like the example embodiments, are used to limit the disclosure. It shouldn't be. Elements included in the drawings in this document may not be drawn to scale.

Example 1

Direct cooling cast ingots of an alloy containing 0.62 wt.% Mg, 0.75 wt.% Si, 0.21 wt.% Cu, 0.13 wt.% Mn, 0.2 wt.% Fe, and 0.02 wt.% Ti were scalped, homogenized, and hot and cold rolled to a final 0.9 mm gauge. A cold rolled strip of coil (Example 1) is solution treated between 540°C and 575°C before coiling in a continuous process in which the strip moves at a speed of 60 meters per minute, then quenched to below 50°C. , were heat spiked in a furnace set at 220°C. There was no intentional (i.e. natural cooling only) cooling between the heat spike and coiling at the end of the process. The strips were sampled before coiling at the flying shear position of the line and after cooling on the finishing line.

Samples taken before and after coiling are tested after 6 days of continuous annealing solution heat treatment (“CASH”) using ASTM samples under as-is paint bake conditions (2% + 20 minutes @185°C - referred to as T8X). It has been done. Table 5 shows that the transverse yield strengths of sheet samples taken before flying shear and coiling in as-is and paint bake tempers are 117 and 229 MPa, respectively, slightly higher than the typical values expected for this alloy. However, the yield strength (YS) values were higher for both tempers for the coil-cooled samples, which is quite surprising since conventional products without heat spikes and coiled at similar temperatures do not exhibit such high properties. These products are generally produced through separate batch aging heat treatment of coils in T4 temper. Without wishing to be bound by theory, it is believed that the disclosed heat spike process accelerates the age hardening process during coil cooling.

Examples 2 to 5

Direct cool cast ingots of four different alloys with the compositions shown in Table 6 were scalped, homogenized, and hot and cold rolled to final gauge. A cold rolled coil strip, such as Example 1, is solution heat treated between 540°C and 575°C in a continuous process moving at 60 meters/min before being coiled at the end of the line and then rapidly cooled to below 50°C. was then heat spiked in a furnace set at 250°C. The strips were sampled before coiling at the flying shear position of the line and after cooling on the finishing line.

Samples of Examples 2 to 5 taken before and after coiling were tested as-is and T8X (2%+20 minutes @185°C) conditions were tested after several days of cache using ASTM samples. Table 7 summarizes the tensile properties of samples Examples 2 to 5 taken on the flying shear and finishing lines. Table 7 confirms the results of Example 1 by showing that all four alloys exhibit significantly higher strengths in the coil cooled samples as compared to the flying shear samples before coil cooling.

Examples 6 to 8

Similar to Examples 2 to 5, three cold rolled coils of alloy Example 4 were solution heat treated in a continuous heat treatment line and heat spiked in the range of 200 to 250°C, without intentional cooling after heat spiking (i.e. natural air cooling). Only) coiled at the end of the line. Samples of Examples 6 to 8, obtained prior to coiling in the flying shear and coiled on the finishing line, were tested using ASTM samples in both as-is and T8X temper. The results of this experiment, summarized in Table 8, show that the heat spiking and coil cooled samples exhibit higher strength compared to the flying shear samples, confirming the effectiveness of heat spiking and the results of the previous examples.

The same coils for Examples 6 to 8 listed in Table 8 were melted in the same way as the first time, but the reboiler was set to automatic mode, 100°C and 150°C, respectively. The results for the resolubilization coil are summarized in Table 9, which shows that strength increases as the thermal spike temperature increases, but the increase is less than that seen at >200°C. As can be seen from these results, the thermal spike temperature has a significant effect on the strength of coil-cooled samples. This observation shows that appropriate selection of alloy and heat temperature can produce a variety of tensile property combinations without additional batch aging processes.

Examples 9 to 10

The purpose of this experiment was twofold: first, to investigate the effect of heating rate during thermal spikes on the strength of AA6111 coils by varying line speed (52 m/min vs. 41 m/min) and second, to determine the tensile properties of AA6111 in H3X temper. Compare with typical 5xxx alloys supplied as .

0.76 wt.% Cu. A pair of 2 mm gauge cold rolled coils (Examples 9 and 10) of AA6111 alloy containing 0.74 wt.% Mg, 0.66 wt.% Si, 0.27 wt.% Fe, and 0.74 wt.% Mn were rolled between 520 and 560°. C, rapidly cooled to below 50°C, and heat spiked in a furnace at 250°C before coiling at the end of the continuous process. The coils of Examples 9 and 10 were heat treated at rates of 52 meters/minute and 41 meters/minute, respectively. Samples from each coil in the finishing line were tested using ASTM samples as-is and in T8X temper. The results of this experiment are summarized in Table 10. The two coils processed at both line speeds show very similar properties in both T4 and T8X tempers, indicating that changing line speeds in the 41 m/min to 52 m/min strip speed range does not significantly affect the tensile properties. The higher strength of the T4 temper potentially allows it to be used in structural parts, offering the possibility of downgauging or eliminating post-forming heat treatment.

Table 11 summarizes typical ASTM tensile properties of commonly used 5xxx alloys. The YS, UTS and total elongation values range from 190 to 290 MPa, 230 to 325 MPa, and 7 to 16%, respectively. The YS of the AA6111 coil in Table 10 is close to 5086-H34 with a significantly higher total elongation. This suggests that the AA6111 material produced by the process described herein can replace the 5086-H34 product while providing better overall elongation. The same alloy can be produced at lower strengths by heat spiking at lower temperatures to match the strengths of other AA5xxx products. Different strength combinations can also be achieved by changing the alloy chemistry along with other process variables.

Heat-spiked AA6xxx does not exhibit any significant natural aging. These properties, along with similar strength and total elongation, provide a very attractive alternative to 5xxx products where high formability is required.

Example 11

A direct cool cast ingot of AA6111 alloy containing 0.69 wt.% Mg, 0.57% wt.% Si, 0.51 wt.% Cu, 0.19 wt.% Mn, 0.23 wt.% Fe and 0.01 wt.% Ti is scalped; It was homogenized, hot and cold rolled to a final 2.3 mm gauge. Cold rolled coil strips were solution heat treated between 525°C, rapidly cooled to below 50°C and heat spiked into a furnace to heat the strip to approximately 190°C in a continuous process and the entire sidewall of the coil at approximately 135°C. It was wound again at temperature. Line speed was adjusted between 17 and 20 meters/min to ensure the strip temperature at the exit of the furnace was close to 190°C. There was no intentional cooling between the heat spike and coiling at the end of the process. The coil temperature is reduced from 135°C to 85°C at approximately 2.8°C/h, with additional cooling to ambient being less than 2°C/h. Coils were sampled after 5 days of heat treatment, ASTM samples were used as is and tested with various paint bake tempers.

Table 12 shows the average transverse ASTM tensile properties of sheet samples taken from coil cooled samples. The yield strength (YS) and ultimate tensile strength (UTS) of the coil cooled sample are 277 and 344 Mpa, respectively, and the total elongation value is 17%. These properties are significantly different from AA6111 coils, which are typically produced at coiling temperatures below 100°C and typically exhibit 125 MPa YS, 230 MPa UTS and 24% total elongation. The properties of the coil are those of a temper aged at 140°C for nearly 50 hours. Without being bound by theory, heat spikes accelerate the curing process during coil cooling. As shown in Table 12, the alloys showed a slight increase in strength when aged at higher temperatures with or without prior straining. The heat spike process produces coils with strength at relatively shorter aging times and better elongation than expected from typical batch annealing processes with elongation less than 14%.

The foregoing description of embodiments, including illustrative embodiments, has been presented for purposes of illustration and description only and is not intended to be exhaustive or to limit the precise forms disclosed. Various modifications, applications and uses thereof will be apparent to those skilled in the art.

As used below, any reference to a series of examples should be construed as a reference to each of these examples separately (e.g., “Examples 1 to 4” will be replaced with “Examples 1, 2, and 3”). or 4").

Example 1 is a process for making a heat treated aluminum alloy, comprising the steps of casting a metal strip; solutionizing the cast metal strip at line speed to produce a solutionized metal strip; air cooling the solutionized metal strip to produce a cooled metal strip; Continuously heat spiking the cooled metal strip at line speed at a temperature of 150°C to 300°C to produce a heat spiked metal strip; and coiling the thermally spiked metal strip to produce a coiled metal strip.

Example 2 is the process of Example 1, but further includes cooling the heat spiked metal strip after heat spiking.

Example 3 is the process of any one of the examples, wherein cooling the heat spiked metal strip includes air cooling the heat spiked metal strip.

Example 4 is the process of Example 1, with only natural cooling of the heat spiked metal strip occurring between the heat spike and coiling.

Example 5 is the process of any one of the examples, wherein the step of coiling the heat spiked metal strip is performed continuously at the end of a continuous line.

Example 6 is the process of any one of the examples wherein the cooling rate of the heat spiked metal strip is less than 10°C/hour.

Example 7 is the process of any one of the examples wherein the cooling rate of the heat spiked metal strip is less than 2°C/hour.

Example 8 is the process of any one of the examples, wherein the coiling temperature of the heat spiked metal strip is 70°C to 130°C.

Example 9 is the process of any one of the examples, wherein the coiling of the heat spiked metal strip is performed at a temperature above 60°C.

Example 10 is the process of any one of the examples, wherein the line speed is at least 10 meters per minute.

Example 11 is the process of any one of the examples, where the line speed is 10 meters/minute to 120 meters/minute.

Example 12 is the process of any one of the examples, with a thermal spike temperature of 150°C to 280°C.

Example 13 is the process of any one of the examples, where the thermal spike temperature is 200°C to 250°C.

Example 14 is the process of any one of the examples, wherein metal strip casting includes continuous casting.

Example 15 is the process of any one of the examples, wherein metal strip casting includes direct cooling (DC casting).

Example 16 is the process of any of the examples, further comprising homogenizing, hot rolling, and cold rolling the metal strip after casting and before solutionizing.

Example 17 is the process of one of the examples wherein heat spiking of the cooled metal strip is performed in a reheat furnace that is at least 12 meters long.

Example 18 is the process of any one of the examples, wherein the solution temperature is from about 480°C to about 590°C.

Example 19 is the process of any one of the examples, wherein air cooling includes cooling the solutionized metal strip to below 50°C.

Example 20 is a heat treated metal strip formed by the process of any of the examples.

Claims (15)

In a method of manufacturing a heat-treated aluminum alloy,
casting a metal strip;
solutionizing the cast metal strip at line speed to produce a solutionized metal strip;
air cooling the solutionized metal strip to produce a cooled metal strip;
Continuously thermally spiking the cooled metal strip at the line speed at a temperature of 150°C to 320°C to produce a thermally spiked metal strip;
and coiling the thermally spiked metal strip to produce a coiled metal strip. The method of claim 1 further comprising cooling the coiled metal strip. 3. The method of claim 2, wherein cooling the coiled metal strip comprises air cooling the heat spiked metal strip. 2. The method of claim 1, wherein only natural cooling of the heat spiked metal strip occurs between the heat spiking and coiling. 2. The method of claim 1, wherein the step of coiling the thermally spiked metal strip is performed continuously at the end of a continuous line. 3. The method of claim 2, wherein the cooling of the coiled metal strip occurs at a rate of less than 10°C/hour. The method of claim 1, wherein the coiling of the thermally spiked metal strip occurs at a temperature of 110°C to 160°C. 2. The method of claim 1, wherein the line speed is greater than 10 meters per minute. 2. The method of claim 1, wherein the line speed is between 10 meters/minute and 120 meters/minute. The method of claim 1, wherein the thermal spike temperature is between 150°C and 300°C. The method of claim 1 further comprising homogenizing, hot rolling, and cold rolling the metal strip prior to solutionizing. The method of claim 1, wherein heat spiking the cooled metal strip is performed in a reheater furnace that is at least 12 meters in length. The method of claim 1, wherein the solution temperature is from about 480°C to about 590°C. The method of claim 1, wherein air cooling the solutionized metal strip comprises cooling the solutionized metal strip to below 50°C. A heat treated metal strip formed by the method of claim 1.