KR20230118949A - High-strength 5XXX aluminum alloy variant and manufacturing method thereof - Google Patents

Abstract

Novel 5xxx series aluminum alloys exhibiting high strength and formability are described herein. The aluminum alloys described herein have higher amounts of Mg content than traditional 5xxx series aluminum alloys and exhibit high strength and formability. The aluminum alloys described herein are produced according to a method comprising continuous casting.

Description

High-strength 5XXX aluminum alloy variant and manufacturing method thereof

Cross-Reference to Related Applications

This application claims the benefit of and priority to U.S. Provisional Application No. 63/160,198, filed March 12, 2021, which is incorporated herein by reference in its entirety for all intents and purposes.

Field

The present disclosure relates to the fields of metallurgy, aluminum alloys, aluminum fabrication, and related fields. In particular, the present disclosure provides novel 5xxx series aluminum alloy variants with improved strength and formability and methods of making the same.

Demand for providing transportation vehicles with better fuel economy is increasing in order to respond to global environmental problems caused by exhaust gases. In order to meet this demand, aluminum alloy materials are being used instead of conventional steel materials because aluminum alloys are lightweight compared to steel. In general, aluminum alloys for producing automotive parts require greater strength and formability to meet the increasing demands of manufacturers.

Many aluminum manufacturers use 5xxx series aluminum alloys (i.e., aluminum alloys containing magnesium as the main alloying element) for automotive components. However, it is difficult to improve the performance of one property (eg strength) of 5xxx series aluminum without compromising the performance of another property (eg formability). Attempts to change the composition have been largely unsuccessful because the mechanical properties (eg strength and formability) and machinability of aluminum alloys are significantly affected by minor changes in composition. For example, the composition of the AA5182 alloy is 4.0% to 5.0% by weight magnesium (Mg) content, 0.2% to 0.5% by weight manganese (Mn) content, 0.35% by weight maximum iron (Fe) content, 0.2% by weight % maximum silicon (Si) content, maximum copper (Cu) content of 0.15% by weight, and maximum chromium (Cr) content of 0.1% by weight. If the Mg content of AA5182 is increased above 5% by weight to improve strength and/or formability, the aluminum alloy will become very susceptible to cracking during the production process. Therefore, it is extremely difficult to produce 5xxx series aluminum alloys with higher strength and/or formability using existing aluminum alloys or production methods.

Applied embodiments of the present disclosure are defined by the claims, not by the solutions of the problems. SUMMARY OF THE INVENTION The summary of the problems is a high-level overview of various aspects of the present invention and introduces some of the concepts further described below in the Detailed Description section. The solution to the problem is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings and each claim.

Aluminum alloys that provide higher strength and formability than existing 5xxx series aluminum alloys are described herein. In some embodiments, the present disclosure provides about 0 - 0.30 wt% Si, 0.01 - 0.40 wt% Fe, 0 - 1.0 wt% Cu, 0.01 - 0.50 wt% Mn, 5.0 - 6.0 wt% Mg, 0 - 0.20 wt% % Cr, 0 - 0.30% Zn, 0 - 0.25% Ti, up to 0.15% by weight impurities, and Al. In some embodiments, the aluminum alloy contains 0.01 - 0.20 wt% Si, 0.01 - 0.30 wt% Fe, 0.01 - 0.90 wt% Cu, 0.01 - 0.40 wt% Mn, 5.1 - 6.0 wt% Mg, 0 - 0.10 wt% Cr, 0 - 0.20 wt% Zn, 0 - 0.10 wt% Ti, up to 0.15 wt% impurities, and Al. In some embodiments, the aluminum alloy contains 0.01 - 0.15 wt% Si, 0.01 - 0.20 wt% Fe, 0.05 - 0.80 wt% Cu, 0.05 - 0.30 wt% Mn, 5.2 - 6.0 wt% Mg, 0 - 0.05 wt% Cr, 0 - 0.10 wt% Zn, 0 - 0.05 wt% Ti, up to 0.15 wt% impurities, and Al. In some embodiments, the aluminum alloy contains 0.01 - 0.06 wt% Si, 0.02 - 0.15 wt% Fe, 0.20 - 0.80 wt% Cu, 0.05 - 0.20 wt% Mn, 5.3 - 6.0 wt% Mg, 0.001 - 0.02 wt% Cr, 0 - 0.05 wt% Zn, 0 - 0.03 wt% Ti, up to 0.15 wt% impurities, and Al. In some embodiments, the aluminum alloy contains 0.01 - 0.05 wt% Si, 0.05 - 0.11 wt% Fe, 0.30 - 0.80 wt% Cu, 0.05 - 0.10 wt% Mn, 5.5 - 5.9 wt% Mg, 0.001 - 0.02 wt% Cr, 0 - 0.01 wt% Zn, 0.001 - 0.03 wt% Ti, up to 0.15 wt% impurities, and Al. In some embodiments, the aluminum alloy includes at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight. In some embodiments, the aluminum alloy includes Fe-containing constituents having a grain size of less than 5 microns. In some embodiments, the number density of Mg ₂ Si particles in the aluminum alloy microstructure is at least 500/mm ² . In some embodiments, the aluminum alloy has a yield strength of at least 130 MPa. In some embodiments, the aluminum alloy has an ultimate tensile strength of at least 300 MPa. In some embodiments, the aluminum alloy has an overall elongation of at least 5%.

In some embodiments, the present disclosure relates to a method of producing an aluminum alloy product, comprising continuously casting an aluminum alloy to form a cast product, wherein the aluminum alloy contains 0 - 0.30% Si, 0.01 - 0.40% by weight. % Fe, 0 - 1.0 wt% Cu, 0.01 - 0.50 wt% Mn, 5.0 - 6.0 wt% Mg, 0 - 0.20 wt% Cr, 0 - 0.30 wt% Zn, 0 - 0.25 wt% Ti, up to 0.15 wt% contains impurities, and Al; optionally flash homogenizing the cast product; hot rolling the cast product to produce a hot rolled product; coiling the hot rolled product; cold-rolling the hot-rolled product to produce a cold-rolled product; and annealing the cold rolled product. In some embodiments, the aluminum alloy includes at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight. In some embodiments, continuously casting includes a solidification rate of at least 1° C./s to produce a cast product. In some embodiments, annealing comprises batch annealing or continuous annealing. In some embodiments, flash homogenizing comprises heating the cast product to 400° C. to 600° C. for less than 10 minutes. In some embodiments, a method includes paint baking the cold rolled product after annealing to produce an aluminum alloy product. In some embodiments, the yield strength of the aluminum alloy product increases by at least 5 MPa after the paint baking step.

Additional aspects, objects, and advantages will become apparent upon consideration of the detailed description.

1 shows a method for producing an aluminum alloy according to some embodiments of the present disclosure.
FIG. 2 shows a graph of the yield strength of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
3 shows a graph of ultimate tensile strength of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
4 shows a graph of the change in tensile properties of the sample aluminum alloy after paint bake simulation measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
5 shows a graph of the uniform elongation (Ag) of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
6 shows a graph of total elongation (A80) of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
7 is a graph of r-values (r(10-15)) of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. indicate
8 shows a graph of average n-values of sample aluminum alloys measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction.
9A and 9B show, respectively, longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction with respect to the rolling direction, respectively, in a process for producing an aluminum alloy including batch annealing or continuous annealing. A graph of the instantaneous average n-values at different strains of sample aluminum alloys measured as .
10 shows the area percentage of Fe-containing constituents in the aluminum alloy microstructure for sample aluminum alloys.
11 shows the number density of Fe-containing constituents in an aluminum alloy microstructure for a sample aluminum alloy.
12 shows area percentages of Mg ₂ Si constituents in aluminum alloy microstructures for sample aluminum alloys.
13 shows the number density of Mg ₂ Si constituents in aluminum alloy microstructures for sample aluminum alloys.
14a-e show photographs of the grain structure of sample aluminum alloys produced in a process comprising batch annealing after cold rolling.
15a-e show photographs of the grain structure of sample aluminum alloys produced in a process involving continuous annealing after cold rolling.

Novel 5xxx series aluminum alloy variants exhibiting high strength and formability and methods for making them are described herein. Surprisingly, the aluminum alloys described herein exhibit high strength and formability and, despite having a higher Mg content than existing 5xxx series aluminum alloys, have the same processing problems (e.g., hot rolled do not have any cracks). The aluminum alloys described herein can be produced using the continuous casting process described herein that allows for higher amounts of Mg (eg, greater than 5% by weight) than other processes for producing 5xxx series aluminum alloys. By incorporating higher levels of Mg and utilizing continuous casting, the aluminum alloys described herein exhibit higher levels of strength and formability without risk of cracking during the production process. The aluminum alloys and methods of producing the aluminum alloys described herein provide superior properties compared to existing 5xxx series aluminum alloys.

Existing AA5182 aluminum alloys for producing automotive components require tightly controlled compositions to meet minimum strength requirements while maintaining formability to produce complex structures. In general, aluminum alloys used to produce automotive parts require greater strength, which requires these automobile parts to be made of aluminum alloys containing a large amount of Mg, such as AA5182 aluminum alloy. However, aluminum alloys with high Mg content are prone to cracking. The traditional approach to reducing cracking is to change the β-phase morphology at grain boundaries by adding some alloying elements that can hinder β-phase formation by providing more nucleation sites or by forming additional grains. (e.g., from continuous to discontinuous). However, higher amounts of Mg exacerbate cracking and result in aluminum alloys with significant formability loss.

The novel 5xxx series aluminum alloy variants described herein have an increased positive Mg content in the aluminum alloy composition, but avoid the cracking problems associated with aluminum alloys with high Mg. In particular, the aluminum alloys described herein include a higher amount of Mg compared to the AA5182 aluminum alloy and achieve higher strength and formability properties. As described herein, increasing the Mg content and incorporating other alloying elements (eg, Mn, Cu, Si, etc.) can achieve higher strength and formability than 5xxx series aluminum alloys (eg, AA5182 aluminum alloy). can provide Specifically, the synergistic combination of alloying elements, as further described herein, produces 5xxx series aluminum alloy variants that exhibit little or no cracking during the production process. By utilizing the continuous casting process, the high Mg content aluminum alloy has a high solidification rate to prevent cracking during the production process. Increasing the Mg content will result in a very high work hardening rate and cause dislocations to pile up, leading to edge cracking during cold rolling, but this can be achieved by performing an intermediate annealing step during cold rolling or a gentle pass schedule during cold rolling ( You can control it by managing the pass schedule). The high Mg content aluminum alloys described herein have improved strength and formability and can replace many existing materials (steel, AA5182 alloy, etc.) in automotive applications.

definition and explanation

As used herein, the terms "invention", "the invention", "this invention" and "the present invention" refer to this patent application and the following claims. It is intended to refer broadly to all subjects of 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.

In this description, reference is made to alloys identified by aluminum industry names, such as "series" or "5xxx". "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys," or "Registration Record of Aluminum Association Alloy Designations" for an understanding of the numbering system most commonly used to name and identify aluminum and its alloys. and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot," all published by The Aluminum Association.

As used herein, the meaning of "a", "an", or "the" includes the singular and plural referents unless the context clearly dictates otherwise.

As used herein, a plate generally has a thickness greater than about 15 mm. For example, the plate may be 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 about 100 mm It may refer to an aluminum product having a thickness exceeding.

As used herein, a shate (also referred to as a sheet plate) generally has a thickness of about 4 mm to about 15 mm. For example, the thickness may be 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 thick.

As used herein, sheet is generally aluminum having a thickness of less than about 4 mm (eg, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm, or less than 0.1 mm). refers to the product. For example, the sheet may have a thickness of about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm , about 2.5 mm, about 2.6 mm about 2.7 mm, about 2.8 mm, about 2.9 mm, about 3 mm, about 3.1 mm, about 3.2 mm, about 3.3 mm, about 3.4 mm, about 3.5 mm, about 3.6 mm, about 3.7 mm, about 3.8 mm, about 3.9 mm, or about 4 mm.

As used herein, formability is defined as fracturing, tearing-off, necking, earing, or wrinkling, spring-back, or galling. ) refers to the ability of a material to be deformed into a desired shape without shape errors such as In engineering, formability can be classified according to the deformation mode. Examples of deformation modes include drawing, stretching, bending, and stretch-flanging.

References to alloy tempers or conditions may be made in this application. For an understanding of the most commonly used alloy temper descriptions, see "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems". The F condition or temper refers to the aluminum alloy from which it was manufactured. O condition or temper refers to an aluminum alloy after annealing. The Hxx condition or temper, also referred to herein as the H temper, refers to an aluminum alloy that is not heat treatable after cold rolling with or without heat treatment (eg, annealing). Suitable H tempers include the HX1, HX2, HX3, HX4, HX5, HX6, HX7, HX8, or HX9 tempers. The T1 condition or temper refers to an aluminum alloy that has been cooled from hot work and naturally aged (eg, at room temperature). The T2 condition or temper refers to an aluminum alloy that has been cooled from hot work, cold worked and naturally aged. The T3 condition or temper refers to a solution heat treated, cold worked, and naturally aged aluminum alloy. T4 condition or temper refers to a solution heat treated and naturally aged aluminum alloy. T5 condition or temper refers to an aluminum alloy that has been cooled from hot work and artificially aged (at elevated temperature). T6 condition or temper refers to solution heat treated and artificially aged aluminum alloys. T7 condition or temper refers to a solution heat treated and artificially overaged aluminum alloy. T8x condition or temper refers to solution heat treated, cold worked, and artificially aged aluminum alloys. The T9 condition or temper refers to a solution heat treated, artificially aged, and cold worked aluminum alloy. W condition or temper refers to aluminum alloys after solution heat treatment.

As used herein, "room temperature" means from about 15°C to about 30°C, such as 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.

All ranges disclosed herein are to be understood as encompassing both endpoints and 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 the minimum value of 1 and the maximum value of 10, inclusive; That is, every subrange starts with a minimum value of 1 or greater, eg, 1 to 6.1, and ends with a maximum value of 10 or less, eg, 5.5 to 10.

The following aluminum alloys are described in terms of their elemental composition in weight percent (wt%) based on the total weight of the alloy. In the specific example of each alloy, the remainder is aluminum, with the sum of impurities up to 0.15% by weight.

alloy composition

Aluminum alloy properties are determined in part by the composition of the aluminum alloy. In certain embodiments, alloy composition can affect or even determine whether an alloy will have properties suitable for a desired application.

The alloys described herein are novel 5xxx series aluminum alloy variants. The alloy exhibits high strength, high formability (eg, good elongation and forming properties), and resistance to cracking during the production process. The properties of an alloy are achieved at least in part due to the elemental composition of the alloy. In some cases, the new 5xxx series aluminum alloy variants described herein may include a higher Mg content than the Mg content of existing 5xxx series aluminum alloys, including one or more of Cu, Mn, and Si, among other elements. in specific amounts as further described below.

In some examples, an aluminum alloy as described herein may have the following elemental composition as provided in Table 1.

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

In some examples, an aluminum alloy as described herein may have the following elemental composition as provided in Table 3.

In some examples, the aluminum alloy may have the following elemental composition as provided in Table 4.

In some examples, the aluminum alloy may have the following elemental composition as provided in Table 5.

silicon

In some examples, the aluminum alloys described herein contain from 0% to 0.30% (eg, from 0% to 0.25%, from 0.01% to 0.20%, from 0.01% to 0.15%, from 0.01% Si, based on the total weight of the alloy). to 0.10%, 0.01% to 0.06%, or 0.01% to 0.05%). For example, the alloy may contain 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14% , 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, or 0.30% Si may be included. All are expressed in weight percent.

steel

In some examples, the aluminum alloys described herein also contain 0.01% to 0.40% (e.g., 0.01% to 0.25%, 0.01% to 0.20%, 0.01% to 0.15%, 0.02% Fe) based on the total weight of the alloy. % to 0.11%, or 0.05% to 0.11%). For example, an alloy may contain 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15% , 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32% %, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, or 0.40% Fe. All are expressed in weight percent. Aluminum alloys can contain up to 0.40% Fe, so they can be produced from higher amounts of recycled aluminum alloys.

copper

In some examples, the aluminum alloys described herein contain up to 1.0% (e.g., 0% to 1.0%, 0.01% to 0.90%, 0.05% to 0.80%, 0.20% to 0.80%) Cu by total weight of the alloy. %, or from 0.30% to 0.80%). For example, an alloy may contain 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15% , 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32% %, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.60%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65% , 0.66%, 0.67%, 0.68%, 0.69%, 0.70%, 0.71%, 0.72%, 0.73%, 0.74%, 0.75%, 0.76%, 0.77%, 0.78%, 0.79%, 0.80%, 0.81%, 0.82 %, 0.83%, 0.84%, 0.85%, 0.86%, 0.87%, 0.88%, 0.89%, 0.90%, 0.91%, 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, or 1.0% Cu. All are expressed in weight percent. In some cases, aluminum compositions comprising Cu in the amounts described herein improve the paint bake response of aluminum alloys. For example, aluminum having the amount of Cu described herein exhibits improved strength and formability after paint bake when the aluminum alloy is subjected to continuous annealing. In addition, high Cu content increases ultimate tensile strength providing a higher work hardening range compared to low Cu content alloys. In some cases, adding Cu in an amount greater than 1.0% by weight to an aluminum alloy composition can cause cracking during casting or hot rolling processes.

manganese

In some examples, the aluminum alloys described herein also contain 0.01% to 0.50% (e.g., 0.01% to 0.40%, 0.01% to 0.30%, 0.01% to 0.15%, 0.05%) Mn, based on the total weight of the alloy. % to 0.30%, 0.05% to 0.20%, 0.05% to 0.15%, or 0.05% to 0.10%). For example, an alloy may contain 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15% , 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32% %, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, or 0.50% Mn. All are expressed in weight percent. In some embodiments, aluminum compositions comprising Mn in the amounts described herein result in good n-values (hardening index). In some cases, aluminum alloys with a Mn content of more than 0.40% by weight reduce the n-value due to the solute drag effect and also increase the volume fraction of the constituent particles with Fe and Si to improve formability. reduces Thus, the amount of Mn in the aluminum alloys described herein is finely controlled to avoid loss of formability.

magnesium

In some examples, the aluminum alloys described herein contain 5.0% to 6.0% Mg (eg, 5.1% to 6.0%, 5.2% to 6.0%, 5.3% to 6.0%, 5.4% to 6.0%, 5.5% to 6.0%) Mg. 6.0%, 5.5% to 5.9%, 5.6% to 5.9%, or 5.6% to 5.8%). In some examples, the alloy can include 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, or 6.0% Mg. All are expressed in weight percent. In some embodiments, the inclusion of Mg in the aforementioned amounts in the alloys described herein acts as a solid solution strengthening element. As described further below and demonstrated in the Examples, aluminum alloys comprising Mg contents in the amounts described herein surprisingly produce aluminum alloys with excellent strength and formability. In some embodiments, aluminum compositions comprising less than 5.0 wt % Mg cannot achieve high strength and/or formability. In some cases, aluminum compositions comprising greater than 6.0 wt% Mg (e.g., 6.5 wt%) result in aluminum alloys that are very difficult to cold roll and require multiple intermediate-annealing steps for rolling; This often results in large amounts of edge cracking during rolling.

chrome

In some examples, the aluminum alloys described herein contain up to 0.20% (eg, 0% to 0.20%, 0% to 0.10%, 0% to 0.05%, 0.001% to 0.05% Cr) by total weight of the alloy. %, 0.001% to 0.02%, 0.005% to 0.05%, or 0.01% to 0.05%). For example, an alloy may contain 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06% , 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, or 0.20% Cr. . In some embodiments, adding Cr in the aforementioned amounts reduces pitting corrosion and increases strength by solid solution hardening. In some cases, Cr is not present in the alloy (ie, 0%). All are expressed in weight percent.

zinc

In some examples, the aluminum alloys described herein contain up to 0.30% (e.g., 0% to 0.25%, 0% to 0.20%, 0% to 0.10%, 0% to 0.05%) Zn, based on the total weight of the alloy. %, 0.001% to 0.05%, 0.001% to 0.02%, 0.005% to 0.05%, or 0.01% to 0.05%). For example, an alloy may contain 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06% , 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23 %, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, or 0.30% Zn. In some cases, Zn is not present in the alloy (ie, 0%). In some cases, the addition of excess Zn (eg greater than 0.30 wt%) degrades corrosion properties. Thus, the amount of Zn in the aluminum alloys described herein is limited. All are expressed in weight percent.

titanium

In some examples, the aluminum alloys described herein contain up to 0.20% (e.g., 0% to 0.20%, 0% to 0.10%, 0% to 0.05%, 0.001%) titanium (Ti) based on the total weight of the alloy. % to 0.05%, 0.001% to 0.02%, or 0.005% to 0.05%). For example, an alloy may contain 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06% , 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, or 0.20% Ti. . In some cases, Ti is not present in the alloy (ie, 0%). All are expressed in weight percent.

microelement

Optionally, the aluminum alloys described herein may further include other trace elements, sometimes referred to as impurities, in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. These impurities may include, but are not limited to, V, Ni, Hf, Zr, Sc, Sn, Ga, Ca, Bi, Na, Pb, or combinations thereof. Thus, V, Ni, Hf, Zr, Sc, Sn, Ga, Ca, Bi, Na, or Pb is present in the alloy in an amount of less than 0.05%, less than 0.04%, less than 0.03%, less than 0.02%, or less than 0.01%. can exist The sum of all impurities does not exceed 0.15% (eg 0.1%). In some instances, the aluminum alloy may include up to 0.15 weight percent to improve corrosion resistance. All are expressed in weight percent. The remaining percentage of each alloy may be aluminum.

characteristic

The aluminum alloys described herein exhibit excellent properties when produced according to the methods described herein. In some embodiments, the aluminum alloys described herein exhibit improved properties compared to existing 5xxx series aluminum alloys when produced according to the continuous casting process described herein in combination with cold rolling followed by batch annealing. In some embodiments, the aluminum alloys described herein exhibit improved properties compared to existing 5xxx series aluminum alloys when produced according to the continuous casting process described herein in combination with cold rolling followed by continuous annealing. The machining step significantly improves the strength and formability properties of the aluminum alloy.

In some examples, aluminum alloy products produced from the aluminum alloys described herein can have a yield strength of about 130 MPa or greater. For example, aluminum alloy products produced from the aluminum alloys described herein may have 130 MPa or greater, 135 MPa or greater, 140 MPa or greater, 145 MPa or greater, 150 MPa or greater, 155 MPa or greater, 160 MPa or greater, 165 MPa or greater, 170 MPa or greater. It may have a yield strength of 175 MPa or more, or 180 MPa or more. In some cases, the yield strength is between about 130 MPa and about 250 MPa (eg, between about 135 MPa and about 200 MPa, between about 140 MPa and 190 MPa, or between about 145 MPa and about 180 MPa), or between. The aluminum alloy products described herein may exhibit a yield strength as described herein when measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, relative to the rolling direction.

In some examples, aluminum alloy products produced from the aluminum alloys described herein can have an ultimate tensile strength of about 300 MPa or greater. For example, aluminum alloy products produced from the aluminum alloys described herein may have 300 MPa or greater, 305 MPa or greater, 310 MPa or greater, 315 MPa or greater, 320 MPa or greater, 325 MPa or greater, 330 MPa or greater, 335 MPa or greater, 340 MPa or greater. It may have a yield strength of 345 MPa or more, or 350 MPa or more. In some cases, the ultimate tensile strength is between about 300 MPa and about 500 MPa (eg, between about 305 MPa and about 450 MPa, between about 310 MPa and about 400 MPa, or between about 315 MPa and about 350 MPa), or between am. The aluminum alloy products described herein may exhibit ultimate tensile strength as described herein when measured in longitudinal (L), transverse (T), and/or diagonal (D) directions, respectively, relative to the rolling direction.

Aluminum alloy products produced from the aluminum alloys described herein also exhibit an increase in yield strength after paint baking. For example, an aluminum alloy product produced from an aluminum alloy described herein may have, after a simulated paint bake cycle, at least 2 MPa, at least 4 MPa, at least 5 MPa, at least 10 MPa, at least 15 MPa, at least 20 MPa, or at least 25 MPa. exhibits increased yield strength. In some embodiments, aluminum alloy products produced from the aluminum alloys described herein have a range of 2 MPa to 100 MPa, such as 5 MPa to 90 MPa, 10 MPa to 80 MPa, 20 MPa to 75 MPa, 25 MPa to 60 MPa. It exhibits an increased yield strength of MPa, 30 MPa to 50 MPa, or 35 MPa to 45 MPa. The aluminum alloy products described herein may exhibit improved yield strength as described herein when measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, relative to the rolling direction. . In some embodiments, the simulated paint bake cycle may include heating the aluminum alloy product to 185° C. for about 20 minutes.

The aluminum alloys described herein produced according to the methods described herein also exhibit high formability. High formability can be measured, for example, by measuring total elongation or uniform elongation. ISO/EN A80 is one standard that can be used to test total elongation. ISO/EN Ag is one standard that can be used to test uniform elongation. In some examples, an aluminum alloy product produced from an aluminum alloy described herein may have an overall elongation (A80) of at least about 5% and up to about 30%. For example, aluminum alloy products produced from the aluminum alloys described herein can contain about 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, or therebetween It may have full elongation. The aluminum alloy products described herein may exhibit total elongation as described herein when measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, relative to the rolling direction.

In some examples, an aluminum alloy product produced from an aluminum alloy described herein may have a uniform elongation (Ag) of at least about 5% and up to about 30%. For example, aluminum alloy products produced from the aluminum alloys described herein can contain about 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, or therebetween It may have a uniform elongation rate. The aluminum alloy products described herein may exhibit uniform elongation as described herein when measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, relative to the rolling direction.

Another measure of formability is the r-value (also known as the Lankford modulus), which is the plastic strain ratio during tensile testing. The r-value is a measure of sheet metal's deep-drawability (i.e., resistance to thinning or thickening of a material when subjected to tension or compression). The r-value can be determined according to ASTM E517 (2020). In some embodiments, aluminum alloy products produced from the aluminum alloys described herein have a 0.45, for example, in any or all directions (longitudinal (L), diagonal (D), and/or transverse (T)). For example, it may have an r-value of at least about 0.50, at least about 0.55, at least about 0.60, at least about 0.65, at least about 0.70, or at least about 0.75. In some embodiments, an aluminum alloy product produced from an aluminum alloy described herein has a range from 0.45 to 0.95 in any or all directions, such as from 0.50 to 0.95, from 0.55 to 0.90, from 0.60 to 0.90, from 0.65 to 0.85, or It may have an r-value of 0.70 to 0.85.

The n-value, or strain hardening exponent, indicates how much a material hardens or becomes stronger when plastically deformed. The n-value can be determined according to ASTM E646 (2020). The n-value measured over the strain range of 10% to 20% is denoted by n(10-20). For example, an aluminum alloy product produced from an aluminum alloy described herein may have a ratio of at least about 0.10 in any individual direction or in all directions (longitudinal (L), diagonal (D), and/or transverse (T)), for example , may have an n(10-20) value of at least about 0.15, at least about 0.20, at least about 0.25, or at least about 0.30. In some embodiments, aluminum alloy products produced from the aluminum alloys described herein may range from 0.10 to 0.50 in any or all directions, such as 0.15 to 0.45, 0.20 to 0.40, 0.25 to 0.40, 0.30 to 0.40, or It may have an n-value of 0.30 to 0.35.

aluminum alloy microstructure

When produced according to the methods described herein, the aluminum alloys described herein possess a grain distribution that results in improved mechanical properties. For example, the aluminum alloys described herein contain higher amounts of Mg (eg, 5.0 wt% to 6.0 wt%) and/or Cu (eg, 0.3 wt% to up to 1.0 wt%) than existing 5xxx series aluminum alloys. % by weight). Despite having higher amounts of Mg and/or Cu, the composition formed of Fe did not increase substantially compared to the AA5182 alloy. As shown in Figures 10 and 11, the particle size distribution of the Fe constituents remains virtually the same. The area fractions of Al _x (Fe,Mn) and Al(Fe,Mn)Si particles in the aluminum alloy microstructure for aluminum alloys with 5.0 wt% to 6.0% Mg were similar to the AA5182 alloy. In addition, the grain size of the Fe-containing constituent particles had a small grain size (eg, less than 5 microns) with a predominance of Al _x (Fe,Mn) grains in the aluminum alloy microstructure, which was similar to that of the AA5182 alloy. Thus, the higher amounts of Mg and Cu in the aluminum alloys described herein did not adversely affect the microstructure of the aluminum alloys.

In some embodiments, the aluminum alloys described herein when produced according to the methods described herein are less than 10 microns, such as less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, or Fe-containing constituents having a particle size of less than 4 microns. In some embodiments, the aluminum alloys described herein, when produced according to the methods described herein, are 0.01 to 10 microns, such as 0.01 to 10 microns, 0.01 to 10 microns, 0.05 to 8 microns, 0.1 to 6 microns, Fe-containing constituents having a particle size of 0.2 to 5 microns, or 0.2 to 4.5 microns.

The amounts and sizes of Fe-containing constituent particles in the aluminum alloys described herein result in improved formability and corrosion resistance properties. Fe-containing constituent particles typically act as crack initiation sites, damaging aluminum alloys when subjected to strain. In addition, when the Fe-containing component particles are large, the possibility of corrosion increases and the corrosion performance deteriorates. Advantageously, the low amount and small size of the Fe-containing constituent particles of the aluminum alloys described herein are beneficial to both formability and corrosion resistance.

The aluminum alloys described herein exhibit increased Mg ₂ Si content compared to the AA5182 alloy when produced according to the methods described herein. Mg and Si are combined into Mg ₂ Si to provide significant strength improvement after age-hardening. 12 and 13 show graphs of Mg ₂ Si particle distribution in aluminum alloys and provide the number density, percentage area, and average size of Mg ₂ Si particles in the example alloys. As shown in Figures 12 and 13, the particle size distribution of Mg ₂ Si particles for the aluminum alloys described herein exceeds that of the AA5182 alloy. For example, FIG. 12 shows that the aluminum alloy had an area percentage of Mg ₂ Si greater than 0.01% and a grain size ranging from 0.2 microns to 5 microns. The number density and area fraction of Mg ₂ Si of the aluminum alloys described herein exceeded that of the AA5182 alloy.

In some embodiments, the aluminum alloys described herein when produced according to the methods described herein are less than 10 microns, such as less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, or Mg ₂ Si particles having a particle size of less than 4 microns. In some embodiments, the aluminum alloys described herein, when produced according to the methods described herein, are 0.01 to 10 microns, such as 0.01 to 10 microns, 0.01 to 10 microns, 0.05 to 8 microns, 0.1 to 6 microns, Mg ₂ Si particles having a particle size of 0.2 to 5 microns, or 0.2 to 4.5 microns.

In some embodiments, the aluminum alloy described herein when produced according to the methods described herein has greater than 0.013%, e.g., greater than 0.013%, greater than 0.015%, greater than 0.018%, greater than 0.020%, greater than 0.021%, or and a peak area fraction of Mg ₂ Si particles greater than 0.025%. In some embodiments, the aluminum alloy described herein when produced according to the methods described herein can range from 0.013% to 0.030%, such as from 0.014% to 0.028%, from 0.015% to 0.025%, from 0.018% to 0.024%, or and a peak area fraction of Mg ₂ Si particles between 0.020% and 0.024%.

In some embodiments, the aluminum alloys described herein when produced according to the methods described herein have greater than 300/mm ² %, eg, greater than 325/mm ² , greater than 350/mm ² , greater than 375/mm ² , number densities of Mg ₂ Si particles greater than 400/mm ² , greater than 425/mm ² , greater than 450/mm ² , greater than 475/mm ² , or greater than 500/mm ² . In some embodiments, an aluminum alloy described herein when produced according to a method described herein has a range of from 300/mm ² to 600/mm ² , such as from 325/mm ² to 575/mm ² , 350/mm 2 to 600/mm ² . number densities of Mg ₂ Si particles of 550/mm ² , 375/mm ² to 525/mm ² , or 400/mm ² to 525/mm ² . In some embodiments, the total number density (overall number density) of the Mg ₂ Si particles is less than 3000/mm ² .

Mg ₂ Si particles dissolve during high temperature annealing (eg, continuous annealing) for solid solution strengthening. Mg ₂ Si particles will form hardening precipitates during paint bake for further strength improvement. Fe-containing constituent particles and Mg ₂ Si particles act as heterogeneous nucleation sites during annealing and create fine grain orientation/random texture for better formability.

How to make aluminum alloy

In certain embodiments, a disclosed alloy composition is a product of a disclosed method. Without intending to limit the disclosure, aluminum alloy properties are determined in part by the formation of the microstructure during manufacture of the alloy. In certain aspects, the manufacturing method for an alloy composition can affect or even determine whether the alloy will have properties suitable for a desired application. In some embodiments, the aluminum alloys described herein can be produced by continuous casting, optional flash homogenization, hot rolling, coiling, cold rolling, and annealing.

In some embodiments, a method may include continuously casting a metal strip. The method of casting the metal strip may be any suitable continuous casting process. Surprisingly, however, the desired results have been achieved using a continuous casting process, such as that described in U.S. Patent No. 10,913,107 entitled "METAL CASTING AND ROLLING LINE", the disclosure of which is incorporated herein in its entirety. is incorporated by reference in After casting, the method includes flash homogenizing the metal strip prior to hot rolling. The flash homogenization temperature and hot rolling period are finely controlled to maintain the large grain size and high strength of the aluminum alloy. The metal strip may be flash homogenized in a furnace at a temperature between 400° C. and 500° C. at a suitable heating rate, followed by holding the temperature for a short period of time (e.g., up to 10 minutes) (“soak or soaking”). . After flash homogenization, the metal strip is hot rolled at a hot rolling temperature of 300° C. to 500° C. to produce a hot rolled product. Hot rolled products can be coil cooled. After coiling, the hot-rolled product is cold-rolled in several cold-rolling passes to produce a cold-rolled product. Cold rolled products can optionally be coiled. In some embodiments, the cold rolled product is batch annealed or continuously annealed to produce an aluminum alloy product.

1 provides one exemplary system 100 for producing the aluminum alloys described herein. In one example, the system 100 includes a continuous caster 105, a furnace 110 (eg, a tunnel furnace), a hot rolling stand 115, a first coiler 120, a cold mill stand 125 , and the second coiler 130 may be included. In some cases, system 100 may be used for discrete or partially discrete continuous casting for casting, rolling, and otherwise manufacturing metal articles (eg, metal strip) suitable for providing dispensable coils of metal strip. and a rolling line. As used herein, the term decoupled refers to removing the speed link between the casting apparatus and the rolling stand(s). For example, the continuous caster 105 can be separated from the hot rolling stand 115 . In some cases, the hot rolling stand 115 can reduce the thickness of the metal strip by 40% to 80%. In some cases, quenching prior to the hot rolling stand may be optional, but may advantageously break down the Fe-containing particles to improve precipitation properties. In some cases, the metal strip cast from the continuous caster 105 may be rolled (eg, hot rolled) prior to coiling. In some cases, after hot rolling the metal strip in multiple passes in the hot rolling stand 115, the metal strip may be coiled in the first coiler 120. The metal strip may be cooled before or simultaneously with coiling in the first coiler 120 . The metal strip can be uncoiled and cold rolled in a cold mill stand 125. In some cases, the cold mill stand 125 can reduce the thickness of the metal strip by more than 50%. After cold rolling, the metal strip is optionally coiled, followed by batch annealing or continuous annealing.

casting

The alloys described herein can be cast into metal articles (eg, metal strip) using a continuous casting (CC) process. 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 (eg, metal strip) from the outlet of the casting cavity. Surprisingly, advantageous results can be achieved by intentionally separating the casting process from the hot rolling process of the continuous casting and rolling system. By separating the continuous casting process from the hot rolling process, it is no longer necessary to closely match the casting speed and rolling speed. Rather, the casting speed can be selected to produce the desired properties in the metal strip, and the rolling speed can be selected according to the requirements and limitations of the rolling equipment. In a separate continuous casting and rolling system, the continuous casting device may coil the metal strip into intermediate coils or conveying coils immediately or immediately after casting. Intermediate coils can be stored or sent immediately to the rolling equipment. In the rolling equipment, the intermediate coils may be uncoiled and the metal strip passed through the rolling equipment to be hot rolled or otherwise processed. The end result of the hot rolling process is a metal strip that can have desired properties for a particular customer. In some cases, the metal strip can be coiled and distributed to, for example, a car factory where automotive parts can be formed from the metal strip. In some cases, the metal strip may be heated at various points after being initially cast in a continuous casting process (eg, by a continuous caster), but the metal strip will remain below the solidus temperature of the metal strip.

The casting device may be any suitable continuous casting device. Surprisingly, however, the desired results have been achieved using a belt casting apparatus, such as that described in U.S. Patent No. 6,755,236 entitled "BELT-COOLING AND GUIDING MEANS FOR CONTINUOUS BELT CASTING OF METAL STRIP"; The disclosure of which is incorporated herein by reference in its entirety. In some cases, particularly desirable results can be achieved using a belt casting apparatus having a belt made of a metal with high thermal conductivity, such as copper. The belt casting apparatus may include a belt made of a metal having a thermal conductivity at casting temperature of at least 250, 300, 325, 350, 375, or 400 watts per meter per Kelvin, although metals with other values of thermal conductivity may be used. can Although the casting apparatus can cast metal strip to any suitable thickness, desired results have been achieved at thicknesses of approximately 5 mm to 50 mm.

In some cases, the casting apparatus is capable of rapid solidification of the metal strip (e.g., at least about 10 times faster than standard DC casting solidification, e.g., at least or about 1° C./s, at least or about 10° C./s, or rapidly solidifying at least or about 100° C./s) and rapid cooling (e.g., rapidly cooling at a rate of at least or about 1° C./s, at least or about 10° C./s, or at least or about 100° C./s). may be configured to provide, which may promote an improved microstructure of the final metal strip. In some cases, the solidification rate can be 100 times higher than that of traditional DC casting. Rapid solidification can create a unique microstructure, including a unique distribution of dispersoid-forming elements that are very uniformly dispersed throughout the solidified aluminum matrix. Rapid cooling of the metal strip may facilitate locking of the dispersoid-forming elements in solid solution, such as immediate quenching immediately after or immediately after the metal strip exits the casting apparatus. The resulting metal strip may be supersaturated with dispersoid-forming elements. The supersaturated metal strip can then be coiled into intermediate coils for further processing in a separate casting and rolling system. In some cases, the dispersoid-forming elements of interest include Mn, Cr, V, and/or Zr. These metal strips, supersaturated with dispersoid-forming elements, when reheated, can very quickly lead to the precipitation of uniformly distributed and desired size dispersoids.

In some cases, rapid solidification and rapid cooling can be performed alone by the casting device. The casting device may be of sufficient length and may have sufficient heat removal properties to produce a metal strip supersaturated in the dispersoid-forming elements. In some cases, the casting device may be of sufficient length and sufficient to reduce the temperature of the cast metal strip to no more than 250°C, 240°C, 230°C, 220°C, 210°C, or 200°C, although other values may be used. It may have heat removal properties. Generally, these casting devices occupy significant space or must operate at slow casting speeds. In some cases where a smaller and faster casting machine is desired, the metal strip may be quenched immediately or immediately after exiting the casting machine. The temperature of the casting device to reduce the temperature of the metal strip to no more than 250°C, 240°C, 230°C, 220°C, 210°C, 200°C, 175°C, 150°C, 125°C, or 100°C, although other values may be used. One or more nozzles can be placed downstream. The quenching may occur rapidly or rapidly enough to immobilize the dispersoid-forming elements in the supersaturated metal strip.

The metal strip can then be subjected to further processing steps. Optionally, additional processing steps may be used to make the sheet. Such processing steps include, but are not limited to, any flash homogenization step, hot rolling step, cold rolling step, and annealing step. The processing steps are described below in relation to the metal strip. However, the machining steps can also be used for cast slabs or strips, using variations known to those skilled in the art.

homogenization

Optionally, when a homogenization step is performed, the metal strip made from the alloy compositions described herein may be heated to a homogenization temperature, such as a temperature ranging from about 400° C. to 600° C. For example, the metal strip is subjected to about 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, It can be heated to 540°C, or 550°C. In some cases, the metal strip may be flash homogenized. Flash homogenization involves subjecting the metal strip to a temperature greater than 500°C (e.g., 500°C to 570°C, 520°C to 560°C, or 560°C or approximately 560°C) for a relatively short period of time (e.g., approximately 1 minute to 10°C). minutes, such as 30 seconds, 45 seconds, 1 minute, 1.5 minutes, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes, or any in between range). This heating may occur between the continuous casting machine and any initial coiling, more specifically between the continuous casting machine and the hot rolling stand prior to coiling, or between the hot rolling stand and coiling. This flash homogenization can help reduce the aspect ratio of Fe-containing particles and can also reduce the size of these particles. In some cases, flash homogenization (e.g., at 570° C. for about 2 minutes) results in beneficial spheroidization and/or refinement of Fe-containing particles that would otherwise require extensive homogenization at higher temperatures. ) can be successfully achieved.

In some cases, an optional soaking furnace (eg, a tunnel furnace) may be located downstream of the continuous belt caster near the outlet of the continuous belt caster to perform flash homogenization. The use of a soaking furnace can facilitate achieving a uniform temperature profile across the lateral width of the metal strip. Also, the soaking furnace can flash homogenize the metal strip, which can produce the metal strip for improved disintegration of Fe-containing particles during hot rolling.

hot rolled

The metal strip, or optionally the homogenized metal strip if a homogenization step is performed, can be subjected to a hot rolling step to produce a hot rolled product. In some cases, the metal strip cast in the continuous caster may be rolled (eg, hot rolled) prior to coiling. Rolling prior to coiling can greatly reduce the thickness, such as at least 30% or more typically 50% to 75%. Although additional stands may be used in some cases, particularly useful results have been found when rolling continuously cast metal strip with a single hot rolling stand prior to coiling. In some cases, this high-reduction (e.g., greater than 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75% thickness after continuous casting) reduction) hot rolling can help break down the Fe-containing particles of the metal strip, among other benefits. In some embodiments, hot rolling is performed at about 300°C to about 500°C (e.g., about 300°C, about 310°C, about 320°C, about 330°C, about 340°C, about 350°C, about 360°C, about 370°C, about 380°C, about 390°C, about 400°C, about 410°C, about 420°C, about 430°C, about 440°C, about 450°C, about 460°C, about 470°C, about 480°C, about 490°C , or about 500° C.).

In some cases, as described herein, a combination of continuous casting followed by flash homogenization and hot rolling can be particularly useful for refining (eg, disintegrating) Fe-containing particles. Hot-rolled products may be cold-coiled after hot-rolling. Hot rolled products may be cold coiled at temperatures ranging from about 200°C to 400°C. In some embodiments, hot rolled products are coil cooled to facilitate cold rolling as well as alter the grain and crystallographic texture of the aluminum alloy. For example, the hot rolled product may be heated to about 200°C (e.g., about 210°C, about 220°C, about 230°C, about 240°C, about 250°C, about 260°C, about 270°C, about 280°C, about 290°C). °C, about 300 °C, about 310 °C, about 320 °C, about 330 °C, about 340 °C, about 350 °C, about 360 °C, about 370 °C, about 380 °C, about 390 °C, or about 400 °C) can be coiled.

cold rolled

Optionally, one or more cold rolling steps may be subsequently conducted to produce a cold rolled product. Hot-rolled products can be uncoiled using an uncoiler. Uncoiled hot-rolled products can be cold-rolled on cold-rolling stands. A hot rolled product can be cold rolled into a thinner product, such as a cold rolled sheet, using a cold rolling mill. Cold rolling is a reduction in gauge of greater than 50% compared to the gauge prior to the start of cold rolling (e.g., greater than 55%, greater than 60%, greater than 65%, greater than 70%, greater than 75%, greater than 80%, greater than 85%; or greater than 90% reduction) to produce a final gauge thickness. In some embodiments, the cold rolling step may include one or more cold rolling steps to achieve a desired gauge thickness reduction. Optionally, the process of producing the aluminum alloy may include an intermediate annealing step (eg between one or more cold rolling steps). In some cases, cold rolled products may be coiled after cold rolling.

annealing

Cold rolled products may be annealed after cold rolling. The annealing process may be batch annealing or continuous annealing.

In some embodiments, batch annealing may be performed after cold rolling. In some cases, the batch-annealing step is about 300°C to about 450°C (e.g., about 310°C, about 320°C, about 330°C, about 340°C, about 350°C, about 360°C, about 370°C, about 380 °C, about 390 °C, about 400 °C, about 410 °C, about 420 °C, about 430 °C, about 440 °C, or about 450 °C). In some cases, the heating rate in the batch-annealing step is from about 10 °C/h to about 100 °C/h (e.g., from about 20 °C/h to about 90 °C/h, from about 30 °C/h to about 85 °C/h). °C/h, about 40 °C/h to about 80 °C/h, about 50 °C/h to about 75 °C/h, about 30 °C/h to about 80 °C/h, about 40 °C/h to about 70 °C/h h, or from about 50 °C/h to about 60 °C/h). In some cases, the cold rolled product is batch-annealed for up to about 5 hours (including, for example, about 30 minutes to about 4 hours, about 45 minutes to about 3 hours, or about 1 hour to about 2 hours). to be cracked. For example, the cold-rolled product is heated at a temperature of about 300 ° C to about 450 ° C for about 20 minutes, about 30 minutes, about 45 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 3 hours, about 4 hours, Cracking can be done for about 5 hours, or any time in between. In one example, the cold-rolled product is heated to a temperature of about 350° C. to about 400° C. at a heating rate of about 50° C./h to about 75° C./h, and soaked for about 1 second to about 2 hours; and cooling at a cooling rate of 5° C./h to about 30° C./h.

In some embodiments, continuous annealing may be performed after cold rolling. In some cases, the continuous-annealing step is about 400 °C to about 600 °C (e.g., about 410 °C, about 420 °C, about 430 °C, about 440 °C, about 450 °C, about 460 °C, about 470 °C, About 480°C, about 490°C, about 500°C, about 510°C, about 520°C, about 530°C, about 540°C, about 550°C, about 560°C, about 570°C, about 580°C, about 590°C, or about 600° C.) at a peak metal temperature. In some cases, the heating rate in the continuous-annealing step is from about 0.1 °C/s to about 30 °C/s (e.g., from about 0.2 °C/s to about 28 °C/s, from about 0.3 °C/s to about 28 °C). /s, from about 0.4 °C/s to about 25 °C/s, from about 0.5 °C/s to about 20 °C/s, from about 0.8 °C/s to about 18 °C/s, from about 1 °C/s to about 15 °C/s , or from about 2 °C/s to about 10 °C/s). In some cases, the cold rolled product is subjected to soaking during the continuous-annealing step for up to about 1 minute (eg, 0 seconds, 5 seconds, 10 seconds, or 30 seconds). In one example, the cold rolled product is heated to a temperature of about 400° C. to about 600° C. at a heating rate of about 0.5° C./s to about 20° C./s, soaked for about 0 seconds to about 5 seconds, and Cooling is performed at a cooling rate of about 5° C./s to about 200° C./s.

Methods of using the disclosed aluminum alloy products

The aluminum alloy products described herein may be used in automotive applications and other transportation applications, including aircraft and rail applications. For example, the disclosed aluminum alloy products include bumpers, side beams, roof beams, cross beams, pillar reinforcement structures (eg, A-pillars, B-pillars, and C-pillars), interior panels, exterior panels, and side panels. , interior hoods, exterior hoods, or trunk lid panels. The aluminum alloy products and methods described herein may also be used in aircraft or rail vehicle applications, for example, to make exterior and interior panels.

The aluminum alloy products and methods described herein may also be used in electronic device applications. For example, the aluminum alloy products and methods described herein can be used to manufacture housings for electronic devices, including cell phones and tablet computers. In some examples, aluminum alloy products may be used to make housings for cell phones (eg, smart phones), tablet bottom chassis, and outer casings of other portable electronic devices.

Example

Example 1: Mechanical properties

Alloys 1-3 are exemplary alloys produced according to the method described below. Alloy A is an existing AA5182 aluminum alloy currently used in automotive body parts.

Alloys 1-3, as shown in Table 6, were continuously cast into metal strips based on the methods described herein. The metal strip was flash homogenized in a tunnel furnace operating at a temperature of 400 °C to 500 °C. Metal strip was hot rolled in a hot mill stand to produce hot rolled products with a 40% to 80% reduction in gauge thickness. The hot rolled product was coil cooled to a temperature of about 350°C. The hot rolled product was uncoiled and cold rolled on a cold mill stand to produce a cold rolled product with a gauge thickness reduced by more than 50%. Cold-rolled products were coiled. Cold rolled products were subjected to either batch annealing or continuous annealing to produce final aluminum alloy products. Alloy A was either direct cold cast or continuously cast.

robbery

The strength properties of the example alloys and comparative alloys were determined. Specifically, the alloy was subjected to yield strength and ultimate tensile strength tests.

2 shows yield strength test results for alloys 1-3 and alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, with respect to the rolling direction. Yield strength values for alloy A when produced using direct chill casting and continuous casting are shown in the first two columns. For each of Alloys 1-3 and Alloy A, yield strength values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars showing yield strengths in the L, T, and D directions, the left bar represents the yield strength after continuous annealing and the right bar represents the yield strength after batch annealing. The yield strength was slightly higher for aluminum alloys obtained after batch annealing compared to continuous annealing. The continuously cast Alloy A example showed an increase in yield strength of about 15 MPa to 20 MPa compared to the direct chill cast example. Alloys 1-3 exhibited higher yield strengths in the L, T, and D directions compared to the two examples of alloy A. The higher Mg content of Alloys 1-3 combined with the production of aluminum according to the continuous casting process described herein resulted in higher strength compared to aluminum alloys produced by direct chill casting due to the high amount of residual solute in solution. Also, alloys 1-3 exhibited higher strength values with increasing amounts of Mg and Cu.

3 shows ultimate tensile strength test results for alloys 1-3 and alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. The ultimate tensile strength values for alloy A when produced using direct chill casting and continuous casting are shown in the first two columns. For each of Alloys 1-3 and Alloy A, ultimate tensile strength values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars showing ultimate tensile strength in the L, T, and D directions, the left bar represents the ultimate tensile strength after continuous annealing and the right bar represents the ultimate tensile strength after batch annealing. The ultimate tensile strength was slightly higher for aluminum alloys obtained after batch annealing compared to continuous annealing. Alloys 1-3 exhibited higher ultimate tensile strength in the L, T, and D directions compared to the two examples of alloy A. Alloys 1-3 produced according to the continuous casting process described herein resulted in higher tensile strength compared to direct chill casting and conventional continuous casting.

Alloys 1-3 and Alloy A were tested to determine the effect of paint baking on the tensile properties of the aluminum alloy. 4 shows tensile strength test results for Alloys 1-3 and Alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, after paint bake simulation. indicates Each alloy was heated to 185° C. and held at this temperature for about 20 minutes in a paint baking simulation. The change in tensile strength values for alloy A when produced using direct chill casting and continuous casting are shown in the first two columns. For each of Alloys 1-3 and Alloy A, the change in tensile strength values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars showing changes in tensile strength values in the L, T, and D directions, the left bar represents the change in tensile strength value after continuous annealing and the right bar represents the change in tensile strength value after batch annealing. Alloy A, regardless of how it was produced, showed no strength increase after the paint bake cycle. Alloys 1-3 showed a higher increase in strength with increasing Cu content in the alloy. For example, alloy 3 containing 0.8 wt% of Cu showed the greatest increase in tensile strength after paint bake simulation. In addition, variants produced using the continuous annealing process showed good response to paint bake due to the high annealing temperature.

formability

The formability properties of the example alloys and comparative alloys were determined. Specifically, the alloys were subjected to uniform elongation, total elongation, r-value, and n-value tests to determine the formability of the exemplary and comparative alloys.

5 shows uniform elongation test results for alloys 1-3 and alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. The uniform elongation values for alloy A produced according to the direct chill casting and continuous casting methods are shown in the first two columns. For each of Alloys 1-3 and Alloy A, uniform elongation values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars showing uniform elongation in the L, T, and D directions, the left bar represents the uniform elongation after continuous annealing and the right bar represents the uniform elongation after batch annealing. Uniform elongation was higher in aluminum alloys obtained after continuous annealing compared to batch annealing. Alloys 1-3 exhibited higher uniform elongation in the L, T, and D directions compared to the two examples of alloy A. Alloys 1-3 had higher uniform elongation with increased amounts of Mg.

6 shows total elongation test results for alloys 1-3 and alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. The total elongation values for alloy A produced according to the direct chill casting and continuous casting methods are shown in the first two columns. For each of Alloys 1-3 and Alloy A, total elongation values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars showing total elongation in the L, T, and D directions, the left bar represents the total elongation after continuous annealing and the right bar represents the total elongation after batch annealing. Overall elongation was higher for aluminum alloys obtained after continuous annealing compared to batch annealing. Alloys 1-3 exhibited higher overall elongation in the L, T, and D directions compared to the two examples of alloy A. Alloys 1-3 had higher overall elongation with increased amounts of Mg.

7 shows the r-values for alloys 1-3 and alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. The r-values of alloy A produced according to the direct chill casting and continuous casting methods are shown in the first two columns. For each of Alloys 1-3 and Alloy A, r-values for the alloys after batch annealing (BA) and continuous annealing (CAL) are provided. For each pair of bars representing the r-values in the L, T, and D directions, the left bar represents the r-value after continuous annealing and the right bar represents the r-value after batch annealing. The r-values were slightly higher for the aluminum alloys obtained after batch annealing compared to continuous annealing. Alloys 1-3 exhibited lower r-values in the L, T, and D directions compared to alloy A.

8 shows the n-values for Alloy 1-3 and Alloy A measured in the longitudinal (L) direction, transverse (T) direction, and/or diagonal (D) direction, respectively, for the rolling direction. The n-values of alloy A produced according to the direct chill casting and continuous casting methods are shown in the first two columns. For each of Alloys 1-3 and Alloy A, n-values for the alloys are given after batch annealing (BA) and continuous annealing (CAL). For each pair of bars representing n-values in the L, T, and D directions, the left bar represents the n-value after continuous annealing and the right bar represents the n-value after batch annealing. The n-values were similar for aluminum alloys obtained after batch annealing and continuous annealing. Alloys 1-3 exhibited higher n-values in the L, T, and D directions compared to the two examples of alloy A. Alloys 1-3 showed about 10% increase in n-value compared to alloy A. Increased Mg content in alloys 1-3 contributed to improved n-values.

9A and 9B show the instantaneous n-values for Alloy 1-3 and Alloy A over a strain range after batch annealing and continuous annealing, respectively. Alloys 1-3 showed higher retention of n-values at higher strains compared to alloy A. Surprisingly, the higher Mg content aluminum alloys of Alloys 1-3 had a much lower rate of decrease in n-value with increasing strain. The batch annealed samples of alloys 1-3 showed a decrease in n-value after 7% strain, whereas the continuously annealed samples showed little observable decrease in n-value. A high n-value at high strain provides a better forming window for Alloys 1-3.

Example 2: Microstructure

Aluminum alloys produced according to the methods described herein exhibit microstructures that provide the properties described herein. 10 and 11 show the particle distribution of Fe-containing constituents in the aluminum alloy microstructure for alloy 2 (dashed line) and alloy A (solid line). The Fe-constituent particle distribution of alloy 2 with a Mg content of 5.8% by weight was similar to that of alloy A. 10 shows that the area fraction of Al _x (Fe,Mn) in alloy 2 is substantially the same as alloy A. Both alloy 2 and alloy A had an area fraction of Al _x (Fe,Mn) less than 0.06%. Similarly, the area fraction of Al(Fe,Mn)Si was substantially the same for Alloy 2 and Alloy A. 11 shows that the number densities of Al _x (Fe,Mn) and Al(Fe,Mn)Si particles in the aluminum alloy microstructure are similar for Alloy 2 and Alloy A. Both Alloy 2 and Alloy A had Fe-constituent particles with a grain size of less than 5 microns with a predominance of Al _x (Fe,Mn) particles in the aluminum alloy microstructure. Although alloy 2 had higher concentrations of Mg and Cu, the alloy composition did not substantially alter the Fe-constituent particle distribution.

12 and 13 show graphs of Mg ₂ Si particle distribution in aluminum alloy microstructures for Alloy 2 (dashed line) and Alloy A (solid line). 12 shows area % of Mg ₂ Si particles in an aluminum alloy microstructure and FIG. 13 shows the number of Mg ₂ Si particles in an aluminum alloy microstructure. Alloy 2 exhibited a higher area fraction and number density of Mg ₂ Si particles compared to Alloy A. Specifically, alloy A has an area % of Mg ₂ Si particles of 0.129 and a number density of Mg ₂ Si particles of 1186.33/mm ² , while alloy 2 has an area % of Mg ₂ Si particles of 0.212 and a number density of Mg ₂ Si particles of 1186.33/mm 2 . The density was 2125.31/mm ² . Mg and Si are combined into Mg ₂ Si to provide significant strength improvement after age-hardening. Thus, alloy 2 exhibited a significant strength advantage over alloy A. As described herein, the carefully balanced composition of an aluminum alloy plays an important role in controlling its strength and formability. In addition, alloy A utilizing direct chill casting can be obtained at a slower cooling rate (eg, 4 °C/s - 6 °C/s) compared to continuous casting (eg, 100 °C/s - 200 °C/s). will result in coarse intermetallic particles for both Fe-containing constituents and Mg ₂ Si particles. Therefore, in the case of alloys with a large amount of solute, the freezing range is wide, making direct cooling casting difficult and hot cracking occurs.

14a-e show photographs of the grain structures for alloy A and alloys 1-3 after batch annealing and FIGS. 15a-e show photographs of the grain structures for alloys A and alloys 1-3 after continuous annealing. Alloy 1-3 produced using batch annealing had elongated grains, whereas alloy 1-3 produced using continuous annealing exhibited equiaxed grains. The addition of Mg to the aluminum alloy composition of Alloys 1-3 slightly refined the grains compared to Alloy A.

Examples of suitable methods and alloy products

Ex. It is an aluminum alloy containing Zn, 0 - 0.25% Ti, impurities up to 0.15% by weight, and Al.

Example 2 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy contains 0.01 - 0.20 wt% Si, 0.01 - 0.30 wt% Fe, 0.01 - 0.90 wt% Cu, 0.01 - 0.40 wt% Mn, 5.1 - 6.0 wt% % Mg, 0 - 0.10 wt% Cr, 0 - 0.20 wt% Zn, 0 - 0.20 wt% Ti, up to 0.15 wt% impurities, and Al.

Example 3 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy contains, by weight, 0.01 - 0.15% Si, 0.01 - 0.20% Fe, 0.05 - 0.80% Cu, 0.05 - 0.30% Mn, 5.2 - 6.0% by weight % Mg, 0 - 0.05 wt% Cr, 0 - 0.10 wt% Zn, 0 - 0.10 wt% Ti, up to 0.15 wt% impurities, and Al.

Example 4 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy contains 0.01 - 0.06 wt% Si, 0.02 - 0.15 wt% Fe, 0.20 - 0.80 wt% Cu, 0.05 - 0.20 wt% Mn, 5.3 - 6.0 wt% % Mg, 0.001 - 0.02 wt% Cr, 0 - 0.05 wt% Zn, 0 - 0.03 wt% Ti, up to 0.15 wt% impurities, and Al.

Example 5 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy contains, by weight, 0.01 - 0.05% Si, 0.05 - 0.11% Fe, 0.30 - 0.80% Cu, 0.05 - 0.10% Mn, 5.5 - 5.9% by weight % Mg, 0.001 - 0.02 wt% Cr, 0 - 0.01 wt% Zn, 0.001 - 0.03 wt% Ti, up to 0.15 wt% impurities, and Al.

Example 6 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy includes at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight.

Example 7 is the aluminum alloy of any preceding or subsequent example, wherein the Fe-containing constituents have a grain size of less than 5 microns.

Example 8 is the aluminum alloy of any preceding or subsequent example wherein the number density of Mg ₂ Si particles in the aluminum alloy microstructure is at least 500/mm ² .

Example 9 is the aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy has a yield strength of at least 130 MPa.

Example 10 is the aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy has an ultimate tensile strength of at least 300 MPa.

Example 11 is an aluminum alloy of any preceding or subsequent example, wherein the aluminum alloy has an overall elongation of at least 5%.

Example 12 is an aluminum alloy product comprising the aluminum alloy of any preceding or subsequent example.

Example 13 is an aluminum alloy product of any preceding or subsequent example, wherein the aluminum alloy product is produced by continuous casting, flash homogenization, hot rolling, and cold rolling.

Example 14 is a method for producing an aluminum alloy product, comprising continuously casting an aluminum alloy to form a cast product, wherein the aluminum alloy contains 0 - 0.30% Si, 0.01 - 0.40% Fe, 0 - 1.0% by weight. Cu, 0.01 - 0.50 wt% Mn, 5.0 - 6.0 wt% Mg, 0 - 0.20 wt% Cr, 0 - 0.30 wt% Zn, 0 - 0.25 wt% Ti, up to 0.15 wt% impurities, and including Al; optionally flash homogenizing the cast product; hot rolling the cast product to produce a hot rolled product; coiling the hot rolled product; cold-rolling the hot-rolled product to produce a cold-rolled product; and annealing the cold rolled product.

Example 15 is a method of any preceding or subsequent example wherein the aluminum alloy includes at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight.

Example 16 is a method of any preceding or succeeding example wherein the continuously casting step includes a solidification rate of at least 1° C./s to produce the cast product.

Example 17 is the method of any preceding or subsequent example, wherein the step of annealing includes either batch annealing or continuous annealing.

Example 18 is a method of any preceding or subsequent example, wherein flash homogenizing comprises heating the cast product to 400° C. to 600° C. for less than 10 minutes.

Example 19 is the method of any preceding or succeeding example, further comprising paint baking the cold rolled product after annealing to produce an aluminum alloy product.

Example 20 is the method of any preceding or succeeding example wherein the yield strength of the aluminum alloy product increases by at least 5 MPa after the paint baking step.

All patents, publications, and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the present invention have been described to achieve the various objects of the present invention. It should be appreciated that these embodiments are merely illustrative of the principles of the present invention. Numerous variations and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the claims below.

Claims (20)

0 - 0.30 wt% Si, 0.01 - 0.40 wt% Fe, 0 - 1.0 wt% Cu, 0.01 - 0.50 wt% Mn, 5.0 - 6.0 wt% Mg, 0 - 0.20 wt% Cr, 0 - 0.30 wt% Zn, 0 - an aluminum alloy comprising 0.25% by weight Ti, impurities up to 0.15% by weight, and Al. The method of claim 1, wherein the aluminum alloy contains 0.01 - 0.20 wt% Si, 0.01 - 0.30 wt% Fe, 0.01 - 0.90 wt% Cu, 0.01 - 0.40 wt% Mn, 5.1 - 6.0 wt% Mg, 0 - 0.10 wt% Cr, 0 - 0.20 wt% Zn, 0 - 0.10 wt% Ti, up to 0.15 wt% impurities, and Al. The method of claim 1, wherein the aluminum alloy contains 0.01 - 0.15 wt% Si, 0.01 - 0.20 wt% Fe, 0.05 - 0.80 wt% Cu, 0.05 - 0.30 wt% Mn, 5.2 - 6.0 wt% Mg, 0 - 0.05 wt% Cr, 0 - 0.10 wt% Zn, 0 - 0.05 wt% Ti, up to 0.15 wt% impurities, and Al. The method of claim 1, wherein the aluminum alloy contains 0.01 - 0.06 wt% Si, 0.02 - 0.15 wt% Fe, 0.20 - 0.80 wt% Cu, 0.05 - 0.20 wt% Mn, 5.3 - 6.0 wt% Mg, 0.001 - 0.02 wt% Cr, 0 - 0.05% Zn, 0 - 0.03% Ti, up to 0.15% by weight impurities, and Al. The method of claim 1, wherein the aluminum alloy contains 0.01 - 0.05 wt% Si, 0.05 - 0.11 wt% Fe, 0.30 - 0.80 wt% Cu, 0.05 - 0.10 wt% Mn, 5.5 - 5.9 wt% Mg, 0.001 - 0.02 wt% Cr, 0 - 0.01% Zn, 0.001 - 0.03% Ti, up to 0.15% by weight impurities, and Al. 6. The aluminum alloy according to any one of claims 1 to 5, wherein the aluminum alloy comprises at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight. aluminum alloy. 7. The aluminum alloy of any one of claims 1-6, wherein the Fe-containing constituents have a grain size of less than 5 microns. 8 . The aluminum alloy according to claim 1 , wherein the number density of Mg ₂ Si particles in the aluminum alloy microstructure is at least 500/mm ² . 9. The aluminum alloy according to any one of claims 1 to 8, wherein the aluminum alloy has a yield strength of at least 130 MPa. 10. The aluminum alloy of any preceding claim, wherein the aluminum alloy has an ultimate tensile strength of at least 300 MPa. 11. The aluminum alloy of any preceding claim, wherein the aluminum alloy has an overall elongation of at least 5%. An aluminum alloy product comprising the aluminum alloy of any one of claims 1 to 11. 13. The aluminum alloy product of claim 12, wherein the aluminum alloy product is produced by continuous casting, flash homogenization, hot rolling, and cold rolling. As a method of producing an aluminum alloy product,
continuously casting an aluminum alloy to form a cast product, wherein the aluminum alloy comprises, by weight 0 - 0.30% Si, 0.01 - 0.40% Fe, 0 - 1.0% Cu, 0.01 - 0.50% Mn, 5.0 - 6.0 0 - 0.20 wt% Cr, 0 - 0.30 wt% Zn, 0 - 0.25 wt% Ti, including up to 0.15 wt% impurities, and Al;
optionally flash homogenizing the cast product;
hot rolling the cast product to produce a hot rolled product;
coiling the hot rolled product;
cold-rolling the hot-rolled product to produce a cold-rolled product; and
Annealing the cold rolled product. 15. The method of claim 14, wherein the aluminum alloy comprises at least one of Mg in an amount of 5.5% to 6.0% by weight and Cu in an amount of 0.30% to 1.0% by weight. 16. The method according to any one of claims 14 or 15, wherein continuously casting comprises a solidification rate of at least 1 °C/s to produce the cast product. 17. The method of any one of claims 14 to 16, wherein annealing comprises batch annealing or continuous annealing. 18. The method of any of claims 14-17, wherein flash homogenizing comprises heating the cast product to between 400°C and 600°C for less than 10 minutes. 19. The method of any one of claims 14 to 18, further comprising paint baking the cold rolled product after annealing to produce an aluminum alloy product. 20. The method of claim 19, wherein the yield strength of the aluminum alloy product increases by at least 5 MPa after the paint baking step.

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