Extruded profile for industrial automotive applications and manufacturing process thereof

Abstract

The invention concerns an extruded profile made of an Al-Mg-Si aluminium alloy designed for industrial automotive applications. extruded profile comprising an Al-Mg-Si alloy containing, in wt.%, Si 0.3 – 1.2, Mg 0.3-1.1, Cu ≤ 0.85, Mn 0.05 - 0.80, Cr 0.01 - 0.20, Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60, Zn 0.15 – 1.0, V ≤ 0.10, Ti ≤ 0.10, Zr ≤ 0.15, other elements < 0.05 each and < 0.15 total, rest aluminium, wherein preferably Free-Si ≥ 0.50 with Free-Si = Si – 0,3 * (Fe + Mn), wherein Si, Fe, and Mn represent the silicon, iron, and manganese content in wt.%. The invention also relates to the manufacturing process to obtain such extruded profile.

Description

[0001] DESCRIPTION

[0002] TITLE: EXTRUDED PROFILE FOR INDUSTRIAL AUTOMOTIVE APPLICATIONS AND MANUFACTURING PROCESS THEREOF

[0003] FIELD OF THE INVENTION

[0004] The present invention describes an extruded profile made of an Al-Mg-Si aluminium alloy designed for industrial automotive applications, such as structural and safety components in automobiles, including crash boxes, bumpers, side impact beams, and rocker panels. The present invention is distinguished by the specific composition of the alloy and an innovative manufacturing process that emphasizes environmental sustainability, using a high proportion of recycled content while maintaining superior mechanical properties.

[0005] BACKGROUND OF THE INVENTION

[0006] Recycling aluminium offers significant benefits by being both cost-effective and environmentally friendly. Producing recycled aluminium, known as secondary aluminium, requires up to 95% less energy than creating new, or primary, aluminium. This process also dramatically lowers CO2 emissions, making it an essential strategy for reducing the environmental impact of aluminium production. The aluminium industry is committed to increasing the use of recycled content in its products.

[0007] In this text, the generic formula "scrap", refers to raw materials for recycling, consisting of aluminium and / or aluminium alloy products resulting from the collection and / or recovery of metals produced at different manufacturing steps or products after use, also known as "post consumer scrap". Unless otherwise stated, reference is made to standard NF EN 12258-3 September 2003 which defines terms relating to aluminium and aluminium alloy scraps. "Coated scrap" is scrap composed of parts having any type of coating, for example paint, varnish, printing ink, plastic, paper, metal.

[0008] Patent application EP4095278A1 describes an AA6xxx alloy extrusions with high strength, typically having an ultimate tensile strength higher than 390 MPa, and high processability, in particular with a high productivity, as well as high surface quality and high corrosion resistance. In particular, the alloy of the invention contains, in wt.%, Si 0.6 - 0.9, Mg 0.55- 0.76, Cu 0.65 -0.9, Mn 0.4 - 0.7, Cr 0.05 - 0.2, Zr 0.10 - 0.19, Fe 0.05 - 0.5, Zn < 1.0, V < 0.10, Ti < 0.10, other elements < 0.05 each and < 0.15 total, rest aluminium. Patent application W02016202810A1 describes a manufacturing process for obtaining 6xxx-series aluminium alloy solid extruded products, comprising Si: 0.3-1.7 wt. %; Mg: 0.1-1.4 wt. %, Cu: 0.1-0.8 wt. %, Zn 0.005-0.7 wt %, one or more dispersoid element, from the group consisting of Mn 0.15-1 wt. %, Cr 0.05-0.4 wt. % and Zr 0.05-0.25 wt. %, Fe at most 0.5 wt. %, other elements at most 0.05 wt. % the rest being aluminium, having particularly high mechanical properties, typically an ultimate tensile strength higher than 400 MPa, preferably 430 MPa, and more preferably 450 MPa without the need for a post-extrusion solution heat treatment operation.

[0009] Patent application JP2005126832A describes an aluminium alloy material for a heat roller superior in high-temperature strength and workability which comprises 0.5-2 mass% Mn, 0.05-0.3 mass% Zr, 0.05-0.5 mass% Cu, 0.05-0.6 mass% Si, 0.05-0.7 mass% Fe and the balance Al with impurities; and has such crystal grains with circle equivalent diameters of 200 pm or larger as to occupy 30% or more by area rate in an arbitrary cross section. The aluminium alloy has a chemical composition including, in addition to the above five elements, one or more elements among 0.5 mass% or less Mg, 0.5 mass% or less Cr, 0.3 mass% or less Zn and 0.3 mass% or less Ti.

[0010] Patent application EP2883973A1 describes a manufacturing process for obtaining extruded products made from a 6xxx aluminium alloy, wherein the said manufacturing process comprises following steps: a) homogenizing a billet cast from said aluminium alloy; b) heating the said homogenized cast billet; c) extruding the said billet through a die to form at least a solid or hollow extruded product; d) quenching the extruded product down to room temperature; e) optionally stretching the extruded product to obtain a plastic deformation typically between 0,5% and 5%; f) ageing the extruded product without applying on the extruded product any separate post-extrusion solution heat treatment between steps d) and f).

[0011] Patent application WO2019206826A1 describes an extruded product made of 6xxx aluminium alloy comprising 0.40-0.80 wt. % Si, 0.40-0.80 wt. % Mg, 0.40-0.70 wt. % Cu, up to 0.4 wt. % Fe, up to 0.30 wt. % Mn, up to 0.2 wt. % Cr, up to 0.2 wt. % V, up to 0.14 wt. % Zr, up to 0.1 wt. % Ti, up to 0.05 wt. % each impurity and total 0.15 wt. %, remainder aluminium, wherein the ratio Mg / Si-free is between 0.8 and 1.2 where Si-free is calculated according to the equation Si-free=Si-0.3*(Mn+Fe) where Si, Mn and Fe correspond to the content in weight % of Si, Mn and Fe of said 6xxx aluminium alloy and to the corresponding extruded product particularly suitable with a tensile yield strength higher than 280 MPa, and excellent crash properties. Patent FR2902800 describes a process for manufacturing a remelting block from scrap, in particular for purifying scrap from alloys in the 2XXX or 7XXX series in terms of iron and silicon, without however eliminating additive elements such as zinc, copper and magnesium.

[0012] However, these additional purification steps can be difficult and costly to implement.

[0013] Patent application W02015 / 151907 Al also mentions the problem of impurity content in recycled alloys.

[0014] The use of primary aluminium is the main contributor to the embedded CO2 in alloys. Due to the extensive use of primary aluminium, the production of aluminium alloys is responsible for a very high carbon footprint. Integrating recycled content like post-consumer scraps into the manufacturing of aluminium alloys for the automotive industry is therefore key to the future development of alloys. The aim of the present invention is to develop alloys with the lowest possible carbon footprint while maintaining superior mechanical properties.

[0015] SUMMARY OF THE INVENTION

[0016] A first object of the invention is an extruded profile comprising an Al-Mg-Si alloy containing, in wt.%,

[0017] Si 0.3 - 1.2,

[0018] Mg 0.3- 1.1,

[0019] Cu < 0.85,

[0020] Mn 0.05 - 0.80,

[0021] Cr 0.01 - 0.20,

[0022] Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,

[0023] Zn 0.15 - 1.0,

[0024] V < 0.10,

[0025] Ti < 0.10,

[0026] Zr < 0.15,

[0027] other elements < 0.05 each and < 0.15 total, rest aluminium,

[0028] and wherein preferably Free-Si > 0.50 with Free-Si = Si - 0,3 * (Fe + Mn) (wherein Si, Fe, and Mn represent the silicon, iron, and manganese content in wt.%).

[0029] A second object of the invention is a method to make an extruded profile comprising the successive steps of

[0030] a) Preparation of at least one recycled content batch made of aluminium end-of-life scrap, each recycled content batch having a known chemical composition, by providing aluminium end-of-life scrap, melting it in at least one batch and analysing the chemical composition, b) Establishment of an aluminium alloy target composition, said aluminium alloy target being within the composition containing, in wt.%,

[0031] Si 0.3 - 1.2,

[0032] Mg 0.3- 1.1,

[0033] Cu < 0.85,

[0034] Mn 0.05 - 0.80,

[0035] Cr 0.01 -0.20,

[0036] Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,

[0037] Zn 0.15- 1.0,

[0038] V<0.10,

[0039] Ti <0.10,

[0040] Zr< 0.15,

[0041] other elements < 0.05 each and < 0.15 total, rest aluminium,

[0042] and wherein preferably the Free-Si > 0.50.

[0043] c) Use of a blending model to prepare a charge,

[0044] i. Select at least one recycled content batch that would result in a composition S, the blending model being configured so that the at least one recycled content batch represent at least 70% by weight of the charge, and wherein the CO2 footprint is at most 2 tonnes CO2 / tonnes of produced aluminium alloy,

[0045] ii. Adjust the charge to the composition S obtained in step i. by adding a necessary amount of primary aluminium and / or production scrap and / or addition elements to obtain an aluminium alloy composition within the aluminium alloy target composition, d) Melting the charge and casting a billet,

[0046] e) Homogenizing the billet,

[0047] f) Cooling the homogenized billet to room temperature,

[0048] g) Reheating the homogenized billet to a temperature from 300 °C to 515 °C,

[0049] h) Extruding at an extrusion speed from 5 m / mn to 15 m / mn said reheated billet to obtain an extruded profile,

[0050] i) Quenching, stretching and aging said extruded profile.

[0051] A third object of the invention is the use of an extruded profile as an automotive component such as a crash box, a bumper, a side impact beam or a side sill, structural and non-structural parts of battery box. DESCRIPTION OF THE INVENTION

[0052] All aluminium alloys referred to in the following are designated using the rules and designations defined by the Aluminium Association in Registration Record Series that it publishes regularly, unless mentioned otherwise.

[0053] Unless otherwise stated, all the indications concerning the chemical composition of the alloys are expressed as a percentage by weight based on the total weight of the alloy. The expression 1.4 Fe means that the iron content expressed as a percentage by weight is multiplied by 1.4. Metallurgical tempers referred to are designated using the European standard EN-515. Static tensile mechanical characteristics, in other words, the ultimate tensile strength Rm (or UTS), the tensile yield strength at 0.2% plastic elongation RpO,2 (or TYS), and elongation A% (or E%), are determined by a tensile test according to NF EN ISO 6892-1.

[0054] The VDA 238.100 testing conditions can be used to evaluate the forming behaviour and the susceptibility to failure of metallic materials during forming processes dominated by bending deformation (e.g. folding operations) or during crash deformation. It permits to measure a bending angle a for a given bending radius and to measure the absorbed energy for a given intrusion deformation. The bending angle a gives also a good estimate on the propensity of the material to present cracks during folding. The higher the bending angle, the lower the susceptibility for crack occurrence.

[0055] The bending angle a is determined by bending, normally to the direction of the extrusion, a coupon according to VDA 238-100. Bending is performed until first crack is observed. The bending angle corresponds to the angle a at which first crack appears as represented at Fig 1. Angle a corresponds to the complementary angle , positioned between the two parts Paand Pb of the coupon 2. Bending angle a is dependent on the thickness of the coupon. To permit to rank products, it is of interest to use a corrected angle a' corresponding to the estimated angle for a e ref thick coupon according to the following formula:

[0056]

[0057] where e corresponds to the thickness of the tested coupon and e ref corresponds to the reference thickness.

[0058] "Recycled content" refers specifically to end-of-life scrap, also known as post-consumer scrap, meaning post-consumer waste that has reached the end of its useful life and is repurposed rather than discarded. This includes items such as discarded window frames, salvaged car parts from junkyards, crushed automobiles, and dismantled airplanes. These materials, once used in their original form, can be sourced in raw condition, compacted for easier handling, or in some cases, separately melted down and re-solidified before being reintegrated into the production cycle. Essentially, post-consumer waste represents a second life for materials that would otherwise be lost.

[0059] The carbon footprints were computed using a digital tool, assuming an end-of-life scrap waste emission factor of 0 ton of CO2 per ton of aluminium. A specific CO2 value per ton of aluminium was assigned to primary aluminium and addition elements based on data factory data according to ISO14067.

[0060] A first object of the invention is an extruded profile comprising an Al-Mg-Si alloy containing, in wt.%,

[0061] Si 0.3 - 1.2,

[0062] Mg 0.3- 1.1,

[0063] Cu < 0.85,

[0064] Mn 0.05 - 0.80,

[0065] Cr 0.01 - 0.20,

[0066] Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,

[0067] Zn 0.15 - 1.0,

[0068] V < 0.10,

[0069] Ti < 0.10,

[0070] Zr < 0.15,

[0071] other elements < 0.05 each and < 0.15 total, rest aluminium,

[0072] and wherein preferably Free-Si > 0.50 with Free-Si = Si - 0,3 * (Fe + Mn) (wherein Si, Fe, and Mn represent the silicon, iron, and manganese content in wt.%).

[0073] According to the invention, an improved 6xxx aluminium alloy allows the same mechanical properties to be maintained despite the effect of high-impurity elements present in recycled content.

[0074] Indeed, metal alloys made from recycled content are a sustainable solution that reduces the environmental footprint while saving natural resources. However, the recycling process does present certain challenges, particularly when it comes to the mechanical properties of the alloys obtained. Indeed, alloys produced from recycled content can offer inferior performance compared to those produced from pure raw materials. One of the main reasons for this decline in quality is the difficulty of precisely controlling the chemical composition of recycled content. Unlike initial production, where alloying elements can be added in precise proportions to achieve the desired properties, recycling often involves melting and blending materials whose composition can vary. This variability can lead to impurities or imbalances in the proportions of alloying elements, compromising mechanical properties such as tensile strength, ductility or corrosion resistance.

[0075] To overcome these potential problems and ensure that alloys made from some recycled content meet the requirements of industrial applications, the inventors have defined minimum required values for the mechanical properties of different alloy families. These minimum values ensure that the alloy made from some recycled content offers a performance comparable to alloys from conventional production. By setting these thresholds, they ensure that alloys made from some recycled content retain adequate strength and durability for rigorous technical applications. Table 1 describes the minimum level of properties to be achieved for each alloy family. Families I, II and III are primarily designed with a focus on mechanical strength, making them ideal for applications where robust structural performance is key. Their composition and properties are tailored to withstand high stress and offer exceptional durability. In contrast, Families IV, V and VI are designed with an emphasis on energy absorption and ductility, making them more suitable for applications requiring flexibility and the ability to deform and being formed without breaking. These alloys excel in scenarios where the material's capacity to absorb impact and endure strain is more critical than sheer strength.

[0076] Table 1 - Mechanical properties requirements

[0077] Corrected TYS UTS Total Elongation

[0078] Alloy Family Bending Angle required (MPa) required (MPa) required (MPa)

[0079] required (°) Family 1 350 380 10 50 Family II 320 340 10 50 Family III 300 320 10 50 Family IV 240 260 10 90 Family V 200 220 10 110

[0080]

[0081] Family VI 180 215 10 110 The composition of the alloy, according to the present invention, is carefully balanced to offer a good compromise between mechanical strength, ductility, and ease of extrusion, while allowing for a high integration of recycled content.

[0082] TYS (Tensile Yield Strength) and UTS (Ultimate Tensile Strength) are two fundamental mechanical properties used to assess the strength and resilience of extruded profiles. The Corrected Bending Angle required (°) is a crucial parameter used to assess the ductility of extruded profiles. It is calculated according to the formula described above with a reference thickness of 2 mm. Ductility, in this context, refers to the material's ability to undergo significant deformation before fracturing, particularly when subjected to bending or other forms of mechanical stress, like crushability. The bending angle gives a precise measure of how much a material can bend before it reaches its limit, which is key for determining its suitability for various applications that involve mechanical loading and deformation. In practical terms, the goal is to establish a minimum guaranteed bending angle as the qualification threshold for the material. Any deformation exceeding this angle will be deemed acceptable, while failure to meet this minimum will result in the material being disqualified from further use in the application. The inventors have made the surprising discovery that, with the specific composition claimed, it is possible to incorporate very high percentages of recycled content in the alloy composition: at least 70%, preferably 75%, even 80% or even more 85%, without compromising the mechanical properties of the alloy. This is particularly unexpected because, in conventional alloys, increasing the amount of recycled material introduces a high level of impurity which typically leads to a degradation in performance. Common issues with high-recycled content alloys include reduced strength, decreased ductility, increased susceptibility to defects or damage, and decreased corrosion resistance, which can make them unsuitable for demanding industrial applications. This discovery is remarkable because it demonstrates that sustainability and performance can coexist. By using such high levels of recycled material, our alloy significantly reduces the environmental impact associated with the extraction and processing of raw materials, while still meeting or exceeding the mechanical requirements for industrial use.

[0083] This new alloy composition allows to maintain mechanical properties at a high level. This is due to the careful selection and balancing of the elements in the chemical composition, which act synergistically to enhance the material's resistance to mechanical stress, despite the presence of impurities.

[0084] Fe is a significant impurity. During remelting, iron can react with other elements present in the alloy, such as silicon (Si). This interaction can lead to the formation of iron-rich metallic phases. Iron can bind to Si to form metallic compounds or phases that are predominantly iron-rich. These phases can capture or "trap" silicon.

[0085] Silicon is a crucial element in many alloys for improving properties such as corrosion resistance, hardness and mechanical strength. When silicon is caught in iron phases, it becomes less available to participate in the reactions which lead to the formation of precipitates that improve the alloy's properties. As a result, the alloy loses some of its mechanical properties, leading to a reduction in overall strength.

[0086] To counter the loss of silicon due to the excessive presence of iron, one approach is to adjust the composition of the alloy by adding additional silicon. This compensates for the amount of silicon that has been captured or rendered unavailable by the iron.

[0087] By adjusting the ratio of free silicon and maintaining the proportions of magnesium (Mg) and free silicon, it is possible to maintain the alloy's mechanical properties. Free silicon is defined as the silicon remaining available in the alloy after subtracting a portion bound to iron and manganese (Mn). Formally, it is calculated as follows: Free-Si = Si - 0,3 * (Fe + Mn) (wherein Si, Fe, and Mn represent the silicon, iron, and manganese content in wt.%). This formula provides an indication of the amount of free silicon (Si) that can be expected in solid solution.

[0088] Preferably, the Free-Si content needs to be at least 0.50% to ensure that the alloy retains its optimal mechanical properties, such as strength, hardness, and ductility. Silicon plays a crucial role in forming strengthening precipitates during heat treatment, which enhances the overall strength of the material. If the Free-Si falls below this threshold, the alloy may lose these beneficial properties, resulting in reduced structural integrity and a lower ability to withstand mechanical stress. Additionally, maintaining a Free-Si content above 0.50% helps to control grain structure during extrusion, improving the alloy's performance in applications that require both formability and durability.

[0089] Figure 2 shows the range in which the Si and Fe content of the alloy can be chosen in the embodiment having the constraint of a Free Silicon greater than or equal to 0.50%. The Free-Si limit is defined in knowledge of the amount of Mn. With the minimum rate of 0.05 wt. % of Mn claimed, the domain of Fe and Si possible is defined by the solid lines on the right, top and bottom of the figure and the dashed inclined line on the left. With the maximum rate of 0.80 wt. % of Mn claimed, the domain of Fe and Si possible is defined by the solid lines on the right, the top and the bottom of the figure and the inclined line in long dashes and dots. These lines help visualize the internal limits that must be respected within the claimed range to ensure Free-Si remains within acceptable thresholds.

[0090] Si, Mg and Cu content are carefully adjusted in order to obtain the desired properties of strength, flow stress and the convenient solidus temperature.

[0091] In a preferred embodiment an extruded profile of the invention is made from an aluminium alloy comprising Si 0.7 - 1.1 wt.%, Mg 0.6 - 0.8 wt.%, Cu < 0.85 wt.%, Mn 0.40 - 0.60 wt.%, Cr 0.06 -0.12 wt.%, Fe 0.26 - 0.64 wt.%, preferably Fe 0.30 - 0.60, Zn 0.15-1.0 wt.%, V < 0.05 wt.%, Ti < 0.06 wt.%, Zr < 0.15 wt.%, other elements <0.05 each and <0.15 total, rest aluminium and wherein preferably the Free-Si > 0.50.

[0092] In a preferred embodiment an extruded profile of the invention is made from an aluminium alloy comprising Si 0.5 - 0.7 wt.%, Mg 0.3 - 0.7 wt.%, Cu < 0.6 wt.% preferably Cu 0.1-0.6 wt.% , Mn 0.05 - 0.20 wt.%, Cr 0.01 - 0.07 wt.%, Fe 0.26 - 0.64 wt.%, preferably Fe 0.30 - 0.60, Zn 0.15-1.0 wt.%, V < 0.10 wt.%, Ti < 0.10 wt.%, Zr < 0.05 wt.%, other elements <0.05 each and <0.15 total, rest aluminium.

[0093] In an embodiment, the content of Si is at least 0.3%, or is at least 0.4%, or is at least 0.5%, or is at least 0.6% and / or is at most 1.2%. or is at most 1.1%, or is at most 1.0%, or is at most 0.9%, or is at most 0.8%, or is at most 0.7%. In one embodiment, the Si content is from 0.3 to 1.2 wt.%, preferably from 0.4 to 1.2 wt.%, more preferably from 0.6 to 1.2 wt.% or from 0.7 to 1.1 wt.%. In another embodiment the Si content is from 0,5 to 0.7 wt.%.

[0094] In an embodiment, the content of Mg is at least 0.3%, or is at least 0.4%, or is at least 0.5%, or is at least 0.6%, or is at least 0.7%, or is at least 0.8%, and / or is at most 1.1%, or is at most 1.0%, or is at most 0.9%. In one embodiment, the Mg content is from 0.3 to 1.1 wt.%, preferably from 0.3 to 0.7 wt.%, or from 0,6 to 0.8 wt.%. Copper is added, in particular to improve mechanical properties. In an embodiment, the content of Cu is at least 0.0%, or is at least 0.1%, or is at least 0.2%, or is at least 0.3%, and / or is at most 0.8%, or is at most 0.7%, or is at most 0.6%, or is at most 0.5%, or is at most 0.4%. In a preferred embodiment, the Cu content is from 0.10 to 0.85 wt.%, preferably from 0.20 to 0.85 wt.%.

[0095] In an embodiment, the content of Mn is at least 0.05%, or is at least 0.15%, or is at least 0.25%, or is at least 0.35%, and / or is at most 0.80%, or is at most 0.70%, or is at most 0.60%, or is at most 0.50%, or is at most 0.40%. In a preferred embodiment, the Mn content is from 0.05 to 0.68 wt.%.

[0096] In an embodiment, the content of Cr is at least 0.02%, or is at least 0.07%, or is at least 0.12%, or is at least 0.17%, and / or is at most 0.25%, or is at most 0.20%. In one preferred embodiment, the Cr content is from 0.01 to 0.15 wt.%.

[0097] In an embodiment, the content of Fe is at least 0.26%, or is at least 0.30%, or is at least 0.35%, or is at least 0.40%, or is at least 0.45%, and / or is at most 0.64%, or is at most 0.60%, or is at most 0.55%, or is at most 0.50%.

[0098] In an embodiment, the content of Zn is at least 0.15%, or is at least 0.20%, or is at least 0.25%, or is at least 0.30%, or is at least 0.35%, or is at least 0.40%, or is at least 0.45%, and / or is at most 1.00%, or is at most 0.95%, or is at most 0.90%, or is at most 0.85%, or is at most 0.80%, or is at most 0.75%, or is at most 0.70%, or is at most 0.65%, or is at most 0.60%, or is at most 0.55%, or is at most 0.50%. In a preferred embodiment, the Zn content is from 0.2 to 0.8 wt.%. In one embodiment the Zn content is from 0.15 to 1.0 wt.%. In another embodiment, the Zn content is from 0.30 to 0.50 wt.%.

[0099] The sum of Fe and Zn is important because it influences the mechanical properties, corrosion resistance, and extrusion behavior of the alloy, ensuring an optimal balance between strength and durability in the final extruded profile.

[0100] The sum Fe+Zn is at least 0.41%. In an embodiment, the sum Fe+Zn is at least 0.45% or is at least 0.50% wherein Fe and Zn represent the iron and zinc content in wt.%.

[0101] The V content is at least 0.00% in weight, or is at least 0.01% in weight, or is at least 0.015%, or is at least 0.02%, and / or is at most 0.10%, or is at most 0.05%, or is at most 0.03%. In an embodiment the V content is from 0.01 wt.% to 0.10 wt.% and preferably from 0.01 wt.% to 0.07 wt.%. The addition of vanadium is advantageous in embodiments where the crash behaviour needs to be improved.

[0102] Ti is preferably added to control the as-cast grain structure at a content lower than 0,10 wt.%. In an embodiment the Ti content is from 0.01 wt.% to 0.07 wt.% and preferably from 0.01 wt.% to 0.05 wt.%.

[0103] The Ti content is at least 0.00% in weight, or is at least 0.01% in weight, or is at least 0.015%, or is at least 0.02%, and / or is at most 0.15%, or is at most 0.10%, or is at most 0.05%.

[0104] Preferably, the composition is adjusted so that the calculated solidus temperature using standard thermodynamic database is from 580 °C to 620 °C, preferably from 585 °C to 610 °C and more preferably from 588 °C to 600 °C, and even more preferably from 589 °C to 594 °C. With this relatively high solidus temperature it is possible to increase extrusion rate without having the risk of incipient melting.

[0105] The extruded profile may be use as an automotive component such as a crash box, a bumper, a side impact beam or a side sill, structural and non-structural parts of battery box.

[0106] Thanks to the important use of recycled content, the carbon footprint for producing a ton of aluminium is significantly reduced. In fact, through recycling, the CO2 emissions for manufacturing one ton of aluminium according to the claimed composition drop below 2 tonnes of CO2, whereas producing aluminium from raw materials can generate up to 10 tonnes of CO2 per ton of aluminium or even reach 20 tonnes of CO2 per ton aluminium when electricity production is based on coal. This drastic reduction in carbon emissions not only minimizes the environmental impact of the industry but also greatly reduces overall CO2 consumption, contributing to the fight against climate change.

[0107] Another object of the invention is a method to make an extruded profile comprising the successive steps of

[0108] a) Preparation of at least one recycled content batch made of aluminium end-of-life scrap, each recycled content batch having a known chemical composition, by providing aluminium end-of-life scrap, melting it in at least one batch and analysing the chemical composition, b) Establishment of an aluminium alloy target composition, said aluminium alloy target being within the composition containing, in wt.%,

[0109] Si 0.3 - 1.2,

[0110] Mg 0.3- 1.1,

[0111] Cu < 0.85,

[0112] Mn 0.05 - 0.80,

[0113] Cr 0.01 -0.20,

[0114] Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,

[0115] Zn 0.15- 1.0,

[0116] V<0.10,

[0117] Ti <0.10,

[0118] Zr< 0.15,

[0119] other elements < 0.05 each and < 0.15 total, rest aluminium,

[0120] and wherein preferably the Free-Si > 0.50.

[0121] c) Use of a blending model to prepare a charge,

[0122] i. Select at least one recycled content batch that would result in a composition S, the blending model being configured so that the at least one recycled content batch represent at least 70% by weight of the charge, and wherein the CO2 footprint is at most 2 tonnes CO2 / tonnes of produced aluminium alloy,

[0123] ii. Adjust the charge to the composition S obtained in step i. by adding a necessary amount of primary aluminium and / or production scrap and / or addition elements to obtain an aluminium alloy composition within the aluminium alloy target composition, d) Melting the charge and casting a billet,

[0124] e) Homogenizing the billet,

[0125] f) Cooling the homogenized billet to room temperature,

[0126] g) Reheating the homogenized billet to a temperature from 300 °C to 515 °C, h) Extruding at an extrusion speed from 5 m / mn to 15 m / mn said reheated billet to obtain an extruded profile,

[0127] i) Quenching, stretching and aging said extruded profile.

[0128] Step a) of the method concerns the preparation of at least one batch made of aluminium end-of-life scrap, each recycled content batch having a known chemical composition, by providing aluminium end-of-life scrap, melting it in at least one batch and analysing the chemical composition.

[0129] It is an essential step in ensuring that the final aluminium alloy has a precise chemical composition and optimum mechanical properties while incorporating a significant amount of recycled content.

[0130] The first sub-step in this method involves collecting recycled aluminium content from a variety of sources. Recycled content can include industrial scrap, end-of-life products, production waste from other processes or aluminium scrap. These materials can come from a variety of industries, including automotive (bodies, engine blocks), aviation (aircraft hulls, mechanical parts), construction (window frames, panels), consumer goods (packaging).

[0131] These materials vary not only in origin, but also in chemical composition, which can influence the quality of the recycled batch and requires particular attention.

[0132] Before being reused, recycled aluminium content must be carefully sorted and cleaned to remove impurities, contaminants, surface coatings, paint, oil or other undesirable substances. This process is critical for several reasons. It ensures that the cleanliness of the recycled batch is maintained and that impurities do not compromise the quality of the final alloy, and it prevents unwanted elements (such as lead or mercury) from interfering with the mechanical and chemical properties of the final product.

[0133] The batches made from recycled content are melted down to form ingots. Each ingot is then analysed to determine its exact chemical composition. As a result, every batch has a known chemical composition because it is derived from an ingot that has been analysed beforehand. Before starting the mixing stage, it is essential to define an aluminium alloy target composition which is comprises in the range composition of the aluminium alloy. This composition must meet specific requirements in terms of mechanical, chemical and performance properties, depending on the material's final applications.

[0134] The blending model is used to optimize the proportions of recycled content and primary materials to achieve the defined target composition. The blending model is a sophisticated digital tool designed to blend multiple streams of selective recycled content batches, each with different chemical compositions, to achieve a target alloy composition. The blending model uses mathematical algorithms or optimization methods to determine the optimal proportion of recycled content batches to include in the total charge. The aim is to maximize the use of recycled content while maintaining consistent quality.

[0135] The blending model is a key for the casting of billets containing recycled content. It achieves this by providing simulated charge compositions. The input for the blending model includes the minimum and maximum specifications for the composition of the desired alloy, as well as the compositions of the materials used to reach this specification. These materials include pure aluminium, production scrap, addition elements, and recycled content.

[0136] Within the blending model, multiple types of recycled content batches can be included to create a blend that maximizes the incorporation of recycled content into the alloy composition. This blend, made from recycled content, has a specific composition S. The blending model prioritizes to achieve the minimum level of CO2 emissions.

[0137] The blending model is configured to ensure that at least one recycled content batch represent at least 70% by weight of the charge, preferably at least 75%, preferably at least 80%, and more preferably at least 85%. This represents a challenge, as recycled batches can vary in terms of chemical composition, and certain contents of elements such as Fe and Zn or other impurities can be difficult to adjust without compromise.

[0138] As well as determining the proportion of recycled content batches, the blending model also incorporates an environmental constraint: the carbon footprint. It must ensure that the overall carbon footprint of the process remains below 2 tonnes of CO2 per tonne of aluminium produced.

[0139] The blending model takes into account several factors linked to CO2 emissions, such as energy consumption in the recycling process, transport of recycled content, and emissions linked to the production of primary aluminium or additive elements. The integration of a high proportion of recycled content generally reduces emissions compared to the use of primary aluminium, which is more energy intensive.

[0140] Once the proportion of recycled content batches has been determined, the blending model adjusts the composition by adding the necessary quantities of primary aluminium, production scrap and addition elements to correct deviations between the composition of recycled batches and the target alloy composition, thus preparing a charge ready for meting and casting.

[0141] Thus, the blending model can be used to optimize several critical parameters: • Chemical conformity: The final alloy meets the target chemical composition as defined with minimal deviations.

[0142] • Maximization of recycled content: at least one recycled content batch represent at least 70% by weight of the charge, in line with environmental objectives.

[0143] • Reduced carbon footprint: The carbon footprint of the process is less than 2 tonnes of CO2 per tonne of aluminium produced, meeting sustainability expectations.

[0144] • Cost minimization: The use of recycled content also reduces production costs compared to the exclusive use of primary materials.

[0145] According to the invention, the manufacturing process for obtaining extrusions made from an alloy of the composition disclosed in step d) allows to obtain an extrusion whose mechanical strength potential is maintained.

[0146] The homogenization temperature of step e) is preferably from 500°C to 600°C and more preferably from 530°C to 590°C, and even more preferably from 540°C to 580°C.

[0147] After the homogenizing of step e) the homogenized cast billet is cooled to room temperature. Then, for the manufacture of the extruded profile, the reheating step g) before extrusion consists in a pre-heating of the homogenized cast billet, between 300°C and 515°C during a period of less than 1 hour, before performing subsequently the extrusion step h).

[0148] Extrusion is carried out at an extrusion rate from 5 m / min to 15 m / min with preferably an entry temperature of the head of the billet from 450°C to 500°C and an entry temperature of the foot of the billet from 400°C to 450°C to obtain an extruded profile. The head of the billet is the first part to be extruded and the foot of the billet is the last part to be extruded.

[0149] After extrusion the extruded profile is quenched, stretched and aged in step i). Quenching can be realized with strong air flow or preferably with a water spray, a water bath and or more preferably through a standing wave. Then, a controlled cold deformation or stretching is applied. The purpose of such stretching is to have a stress-relieved and straight extrusion, according to the deformation it underwent during step i). The extrusion is stretched, which induces a plastic deformation, preferably of at least 0.1 % and preferentially of at least 0.5 % and preferably of at most 4%, more preferably of at most 2% and even more preferably of at most 1%.

[0150] Finally, the extrusion is artificially final aged. In one embodiment, the extrusion is aged to a T6 temper. In a preferred embodiment, the ageing temperature is from 160°C to 180°C for a duration from 2 to 5 hours. In another embodiment, the extrusion is overaged to a T7 temper. Example

[0151] In this example, several charges were prepared with selection of ingots coming from recycled content batches and adjustment with primary aluminium amounts, production scraps and addition elements to produce target alloy compositions according to the invention (Alloys A, B, C, D, E, F, G, H) shown in Table 2.

[0152] Starting from a target alloy composition, a blending model selected, recycled content batches to provide a blend having a composition S and determined the amount of pure aluminium, production scrap and addition elements to achieve the target composition. This blending model helps optimize the combination of recycled materials and primary metals and other additional elements needed, ensuring the target alloy composition is met while minimizing the environmental impact, particularly in terms of CO2emissions per ton of aluminium produced. The target composition of the alloys tested is provided in Table 2.

[0153] For each alloy A, B, C, D, E and F, corresponding to a specific alloy family, reference products without recycled content are also tested to compare their mechanical properties. This comparison allows to assess the impact of using recycled materials on the alloy's performance. By evaluating both products made from alloys produced with recycled content and products made from reference alloys made without recycled content, we can determine how the incorporation of recycled content affects key mechanical characteristics such as strength, durability, ductility and corrosion resistance. This analysis ensures that alloys containing scrap meet the required standards while offering a sustainable alternative to alloys fully elaborated from primary aluminium.

[0154] For alloys G and H, products with lower recycled content have also been tested (Alloys G' and H') to evaluate the impact of the recycled content on mechanical properties. This will allow us to determine if a product with a recycled content higher than 70% has lower mechanical properties than a comparable composition with less recycled content.

[0155] Table 2 - Alloy composition in wt.%

[0156] Free- Alloy Family Si Fe Cu Mn Mg Cr Zn Ti V Zr

[0157] Si A 0.79 0.35 0.80 0.54 0.65 0.10 0.34 0.03 0.01 0.14 0.52

[0158] 1

[0159] Ref A 0.79 0.21 0.80 0.53 0.65 0.10 0.03 0.04 0.02 0.14 0.57 B 0.88 0.36 0.23 0.54 0.75 0.08 0.31 0.02 0.01 0.13 0.61 II

[0160] Ref B 0.88 0.21 0.23 0.55 0.75 0.09 0.05 0.03 0.02 0.14 0.5 C 1.12 0.34 0.11 0.48 0.67 0.10 0.31 0.02 0.01 0 0.87 III

[0161]

[0162] Ref C 1.09 0.21 0.11 0.47 0.64 0.05 0.02 0.03 0.01 0.01 0.89 D 0.66 0.33 0.60 0.16 0.59 0.05 0.30 0.09 0.10 0 0.51 IV

[0163] Ref D 0.64 0.22 0.60 0.09 0.59 0.02 0.03 0.03 0.07 0 0.55 E 0.64 0.35 0.13 0.12 0.52 0.01 0.31 0.02 0.07 0 0.50 V

[0164] Ref E 0.63 0.20 0.13 0.07 0.51 0.01 0.02 0.02 0.07 0 0.55 F 0.71 0.49 0.18 0.20 0.30 0.01 0.49 0.01 0.01 0 0.50 Ref F 0.46 0.22 0.02 0.02 0.43 0.01 0.02 0.01 0.02 0 0.39

[0165] VI

[0166] G 0.44 0.26 0.06 0.09 0.44 0.01 0.25 0.01 0.01 0 0.34 G' 0.44 0.26 0.06 0.09 0.44 0.01 0.25 0.01 0.01 0 0.34 H 0.56 0.33 0.21 0.13 0.92 0.01 0.27 0.08 0.05 0 0.42 V

[0167] H'

[0168]

[0169] 0.51 0.20 0.20 0.07 0.91 0.01 0.01 0.09 0.08 0 0.43 For each alloy, the solidus temperature, the scrap content, and the carbon footprint are calculated. The solidus temperature, the scrap percentage and the CO2 footprint (in t CO2 / t aluminium produced) are included in Table 3.

[0170] The solidus temperature of each alloy is calculated using the ThermoCalc software, which simulates the alloy's thermodynamic properties and phase transitions. This software allows determination of the temperature at which the alloy begins to melt, a critical parameter for processing and casting. In addition, the percentage of scrap content and the carbon footprint are measured using the blending model.

[0171] Table 3 - Solidus temperature and energy and environmental costs

[0172] Solidus Temperature %End-of-Life Scrap

[0173] Alloy t CO2 / 1 of Al (°C) Content

[0174] A 582 96 0.37

[0175] Ref A 578 0 8.53

[0176] B 595 97 0.29

[0177] Ref B 592 0 8.53

[0178] C 585 99 0.07

[0179] Ref C 587 0 8.52

[0180] D 591 92 0.72

[0181] Ref D 592 0 8.51

[0182] E 605 84 1.42

[0183] Ref E 605 0 8.52

[0184] F 610 88 0.94

[0185] Ref F 622 0 8.49

[0186] G 621 99 0.09

[0187] G' 621 49 4.30

[0188] H 600 85 1.44

[0189] H' 601 20 6.90

[0190]

[0191] An extruded profile was manufactured from each of the compositions in Table 2 by following the steps described. Each charge prepared by the blending model was melted. Each melted charge was cast in billet of 80 mm diameter. Each billet was homogenized and cooled to room temperature. Then, the homogenized billet was reheated between 470°C and 490°C and introduced into the container of the extrusion press to produce an extruded profile. The extruded profile was then quenched down to room temperature with a cooling device. Then a controlled cold deformation up to 1% was applied to obtain a straight extruded profile. Finally, the extruded profile was aged to a T6 temper then evaluated for tensile properties and bending performance calculated with a reference thickness of 2mm.

[0192] The extruded exit temperature and the mechanical properties are provided in Table 4.

[0193] Table 4 - Mechanical properties and Exit temperature measurements

[0194] Corrected.

[0195] UTS TYS Total El. Extruded Exit Alloy TYS (MPa) Bend. Angle

[0196] (MPa) (MPa) Temp (°C) (°)

[0197] A 365 404 10.9 61.3 578 Ref A 349 382 13.0 90.2 568 B 333 353 10.8 75.1 578 Ref B 327 349 11.0 75.1 573 C 334 361 13.5 75.2 573 Ref C 319 348 13.8 89.2 570 D 292 314 11.9 153.7 563 Ref D 289 310 12.4 148.7 552 E 260 278 10.5 162.4 559 Ref E 258 276 11.2 165.8 552 F 192 225 10.8 173.3 562 Ref F 193 218 11.2 175 556 G 222 257 18.5 146 556 G' 222 257 19.0 146 555 H 293 311 13.5 136 554 H' 299 313 12.7 132 560

[0198]

[0199] Table 4 shows that no tearing was observed as the exit temperature when extruded at 14 m / min is still below the calculated solidus and that the mechanical properties fulfilled the requirements set in Table 1 of the description, which indicates good productivity.

[0200] Thus, the alloys are produced with a percentage of recycled content higher than 80% and this allows to produce alloys with a carbon footprint lower than 2 t CO2 / t aluminium produced. Moreover, these alloys formulated from an optimal proportion of recycled content allow the production of extruded profiles retaining excellent mechanical properties as indicated in Table 4.

[0201] The results of Table 4, show that the products made from alloys comprising recycled content demonstrate mechanical properties comparable to products made from the reference alloys within their respective families. This demonstrates that, in addition to meeting the required criteria outlined in Table 1, products made with part of recycled-content alloys possess nearly identical properties to those produced without recycled content. Therefore, the use of scrap materials does not compromise the performance of the alloys, making them a viable and sustainable alternative to alloys produced using predominantly primary aluminium. The results show also for alloy G and H that, even with a high amount of recycled content, the mechanical remain stable

Claims

CLAIMS1. An extruded profile comprising an Al-Mg-Si alloy containing, in wt.%,Si 0.3 - 1.2,Mg 0.3- 1.1,Cu < 0.85,Mn 0.05 - 0.80,Cr 0.01 - 0.20,Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,Zn 0.15 - 1.0,V < 0.10,Ti < 0.10,Zr < 0.15,other elements < 0.05 each and < 0.15 total, rest aluminium,and wherein preferably Free-Si > 0.50 with Free-Si = Si - 0,3 * (Fe + Mn), wherein Si, Fe, and Mn represent the silicon, iron, and manganese content in wt.%.

2. An extruded profile according to claim 1 wherein the Cr content is from 0.01 to 0.15 wt.%.

3. An extruded profile according to claim 1 or 2 wherein the Mn content is from 0.05 to 0.68 wt.%4. An extruded profile according to anyone of claims 1 to 3 wherein Fe + Zn > 0.41, wherein Fe, and Zn represent the iron and zinc content in wt.%.

5. An extruded profile according to anyone of claims 1 to 4 wherein the extruded profile comprising an Al-Mg-Si alloy containing, in wt.%,Si 0.7 - 1.1,Mg 0.6- 0.8,Cu < 0.85,Mn 0.40 - 0.60,Cr 0.06 - 0.12,Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,Zn 0.15 - 1.0,V < 0.05,Ti < 0.06,Zr< 0.15,other elements < 0.05 each and < 0.15 total, rest aluminium,and wherein preferably Free-Si > 0.50.

6. An extruded profile according to anyone of claims 1 to 4 wherein the extruded profile comprising an Al-Mg-Si alloy containing, in wt.%,Si 0.5 -0.7,Mg 0.3- 0.7,Cu < 0.6,Mn 0.05 - 0.20,Cr 0.01 -0.07,Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,Zn 0.15- 1.0,V<0.10,Ti <0.10,Zr < 0.05,other elements < 0.05 each and < 0.15 total, rest aluminium,and wherein preferably Free-Si > 0.50.

7. An extruded profile according to anyone of claims 1 to 5 wherein the Cu content is from 0.10 to 0.85 wt.%, preferably from 0.20 to 0.85 wt.%.

8. An extruded profile according to anyone of claims 1 to 7 wherein the Zn content is from 0.20 to 0.8 wt.%.

9. An extruded profile according to claim 6 wherein the Cu content is from 0.1 to 0.6 wt.%.

10. An extruded profile according to anyone of claims 1 to 9 wherein the alloy comprises at least 70% of recycled content, preferably at least 75%, and more preferably at least 80%.

11. An extruded profile, according to anyone of claims 1 to 10 wherein the CO2 footprint of the extruded profile is at most 2 tonnes CO2 / tonnes of produced aluminium alloy.

12. An extruded profile according to anyone of claims 1 to 11 wherein the solidus temperature of the alloy is from 580 °C to 620 °C, preferably from 585 °C to 610 °C and more preferably from 588 °C to 600 °C.

13. A method to make an extruded profile according to anyone of claims 1 to 12 comprising the successive steps ofa) Preparation of at least one recycled content batch made of aluminium end-of-life scrap, each recycled content batch having a known chemical composition, by providing aluminium end-of-life scrap, melting it in at least one batch and analysing the chemical composition,b) Establishment of an aluminium alloy target composition, said aluminium alloy target being within the composition containing, in wt.%,Si 0.3 - 1.2,Mg 0.3- 1.1,Cu < 0.85,Mn 0.05 - 0.80,Cr 0.01 - 0.20,Fe 0.26 - 0.64, preferably Fe 0.30 - 0.60,Zn 0.15 - 1.0,V < 0.10,Ti < 0.10,Zr < 0.15,other elements < 0.05 each and < 0.15 total, rest aluminium,and wherein preferably the Free-Si > 0.50.c) Use of a blending model to prepare a charge,i. Select at least one recycled content batch that would result in a composition S, the blending model being configured so that the at least one recycled content batch represent at least 70% by weight of the charge, and wherein the CO2 footprint is at most 2 tonnes CO2 / tonnes of produced aluminium alloy, ii. Adjust the charge to the composition S obtained in step i. by adding a necessary amount of primary aluminium and / or production scrap and / or addition elements to obtain an aluminium alloy composition within the aluminium alloy target composition,d) Melting the charge and casting a billet,e) Homogenizing the billet,f) Cooling the homogenized billet to room temperature,g) Reheating the homogenized billet to a temperature from 300 °C to 515 °C, h) Extruding at an extrusion speed from 5 m / mn to 15 m / mn said reheated billet to obtain an extruded profile,i) Quenching, stretching and aging said extruded profile.

14. A method to make an extruded profile according to claim 13 wherein the at least one recycled content batch represent at least 75% by weight of the charge, preferably at least 80%, and more preferably at least 85%.

15. Use of an extruded profile according to anyone of claims 1 to 12 as an automotive component such as a crash box, a bumper, a side impact beam or a side sill.

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