Aluminum alloy for recycling and manufacturing method

Abstract

The invention relates to an aluminum alloy having the following composition, in % by weight: Si: about 1.7% – about 7.0%, Fe: about 0.3% – about 0.5%, Cu: about 0.3% – about 1.0%, Mn: about 0.2% – about 0.6%, Mg: about 0.2% – about 0.6%, Zn: about 0.2% – about 0.6%, Ti, Cr, Sn, Pb, Zr, V, Sr, Ni: ≤ about 0.1%, other elements: each ≤ 0.05%, together ≤ 0.15%, remainder: Al. The invention also relates to a rolled product made of alloy according to the invention. The alloy according to the invention is particularly suitable for recycling, preferably comprises at least 20% of post-consumer waste, preferably originating from end-of-life vehicles, more preferably originating from aluminum fragmented by car crushers, Twitch.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Aluminum alloy for recycling and manufacturing process

[0003] Field of invention

[0004] The invention relates to the field of aluminum alloys intended for the manufacture of parts for motor vehicles produced from recycled products.

[0005] State of the art

[0006] Aluminum alloys are increasingly used in automotive construction to reduce vehicle weight and thus reduce fuel consumption and greenhouse gas emissions.

[0007] Aluminum alloys used in automotive manufacturing are typically recycled into castings, particularly engine parts. However, the shift from combustion engines to electric motors in automotive propulsion will eliminate this recycling channel.

[0008] There is therefore a demand for aluminum alloys made from recycled products, which is all the more important as manufacturers must increase the use of recycled products to reduce the quantity of CO2 equivalent emitted by vehicle production.

[0009] Application US20210108293 discloses an aluminum alloy sheet having a chemical composition containing Si: 2.3-3.8 mass%, Mn: 0.35-1.05 mass%, Mg: 0.35-0.65 mass%, Fe: 0.01-0.45 mass%, and at least one element selected from the group consisting of Cu: 0.0010-1.0 mass%, Cr: 0.0010-0.10 mass%, Zn: 0.0010-0.50 mass%, and Ti: 0.0050-0.20 mass%. The ratio of the Si content to the Mn content is 2.5 or more and 9.0 or less. Aluminum alloy sheet has an elongation of 23% or more and a work hardening exponent of 0.28 or more at a nominal strain of 3%. Such aluminum alloy sheet is well suited for press forming (stamping) applications, such as automotive body panel forming.

[0010] WO2018 / 175876 discloses techniques for casting metal products with high strength and formability from recycled scrap metal, without adding a substantial amount or even any primary aluminum. Additional alloying elements, such as magnesium, can be added to scrap metal, which can be cast and processed to produce a metal coil of a desired final thickness and having desirable metallurgical and mechanical properties, such as high strength and formability. Inexpensive, recycled scrap metal can thus be efficiently reused for new applications, such as automotive or as a raw material for beverage cans.

[0011] Application JP2005298922 addresses the problem of inexpensively providing an aluminum alloy sheet for forming, which has adequate bending formability, low bending anisotropy and superior bake hardening ability after coating, which has low room temperature aging and adequate line mark resistance.Its solution is an aluminum alloy sheet made of an Al-Mg-Si base alloy or an Al-Mg-Si-Cu base alloy; satisfying each condition of (C1 / 10+ CI / 4) / 2 > C1 / 2 and 30 < (C1 / 10+C1 / 4) < 500, when C1 / 10, Ci / 4 and Ci / 2 are defined as the cube orientation density at positions of 1 / 10, 1 / 4 and 1 / 2 depth from the sheet surface in the sheet thickness direction, respectively; has an orientation density {001} <210> in a range of 2 to 50, in a region of 1 / 10 to 1 / 4 depth in the direction of the sheet thickness; and has horn rates at 0 degrees and 90 degrees of 5% or more. The manufacturing method includes strictly prescribed casting and hot rolling conditions. The conditions of metallographic structures in a cast plate and a sheet after being hot rolled, which are intermediate products, are prescribed.

[0012] Application WO2022 / 026825 discloses novel 6xxx aluminum alloys. In one approach, a novel 6xxx aluminum alloy may comprise 0.25-0.60 wt.% Fe, 0.8-1.2 wt.% Si, 0.35-1.1 wt.% Mg, 0.05-0.8 wt.% Mn, up to 0.30 wt.% Cu, up to 0.35 wt.% Zn, up to 0.15 wt.% Ti, up to 0.15 wt.% each of Cr, Zr, and V, with the remainder being aluminum, accessory elements, and impurities. The novel 6xxx aluminum alloys may be made from recycled aluminum alloys.

[0013] WO9960181 discloses an automotive aluminum alloy which has an aluminum alloy composition comprising 3.5-5 wt% Si, 0.3-1.5 wt% Mg, 0.4-1.5 wt% Zn, 0.4-1.5 wt% Cu, 0.4-1.5 wt% Fe and 0.6-1 wt% Mn, and further one or more of 0.01-0.2 wt% Cr, 0.01-0.2 wt% Ti, 0.01-0.2 wt% Zr and 0.01-0.2 wt% V, the residue of the composition being aluminum and obligatory impurities.

[0014] Application JP2000063972 discloses an extruded aluminum alloy containing Si 2.6 wt% to 4.0 wt%, more than Mg 0.3 wt% to 1.5 wt%, more than Zn 0.3 wt% to 1.2 wt%, more than Cu 0.3 wt% to 1.2 wt% or less and more than Fe 0.1 wt% but 1.5 wt% or less, and in addition, more than Mn 0.01 wt% but 0.3 wt% or less, more than Cr 0.01 wt% but 0.3 wt% or less, more than Zr 0.01 wt% but 0.3 wt% or less, and more than V 0.01 wt% but 0.3 wt% or less, and the remainder Al and unavoidable impurities, wherein a electrical conductivity is not greater than 50% IACS, and a melting initiation temperature is not greater than 570°C.

[0015] US6607615 discloses an extruded aluminum alloy material for structural members of automobile bodies, which is composed of an aluminum alloy containing more than 2.6 wt% but 4.0 wt% or less of Si and more than 0.3 wt% but 1.5 wt% or less of Mg, further containing (i) Mn, Zn, Cu and Fe each in a given amount, or (ii) Zn, Cu and Fe each in a given amount and containing at least one element selected from Mn, Cr, Zr and V in a given amount, the remainder being Al and unavoidable impurities, this material having a given conductivity and a given melting onset temperature.

[0016] US6325870 discloses an aluminum sheet material for automobiles, having an aluminum alloy composition: (i) comprising 3.5 to 5 wt% Si, 0.3 to 1.5 wt% Mg, 0.4 to 1.5 wt% Zn, 0.4 to 1.5 wt% Cu, 0.4 to 1.5 wt% Fe, and 0.6 to 1 wt% Mn, and one or more members selected from the group of 0.01 to 0.2 wt% Cr, 0.01 to 0.2 wt% Ti, 0.01 to 0.2 wt% Zr, and 0.01 to 0.2 wt% V, with the balance being aluminum and unavoidable impurities, or (ii) comprising between more than 2.6 wt% and 5 wt% weight of Si, 0.2 to 1.0 wt% of Mg, 0.2 to 1.5 wt% of Zn, 0.2 to 1.5 wt% of Cu, 0.2 to 1.5 wt% of Fe, and between 0.05 and less than 0.6 wt% Mn, and one or more elements selected from the group of 0.01 to 0.2 wt% Cr, 0.01 to 0.2 wt% Ti, 0.01 to 0.2 wt% Zr, and 0.01 to 0.2 wt% V, with the balance of aluminum and unavoidable impurities. It is possible to produce aluminum sheet for automobiles that has excellent mechanical strength and bending properties, as well as improved weldability, by using recycled aluminum materials.

[0017] US6355090 discloses an aluminum alloy that comprises 0.5 to 5.0 wt% Si, 0.2 to 5.0 wt% Mg, 0.01 to 1.2 wt% Mn, 0.1 to 1.2 wt% Zn, 0.2 to 1.2 wt% Cu, 0.2 to 2.0 wt% Fe, and one or more of the following: 0.01 to 0.2 wt% Cr, 0.01 to 0.2 wt% Zr, 0.01 to 0.2 wt% V, and 0.01 to 0.2 wt% Ti, with the balance being Al and unavoidable impurities.

[0018] However, a recycling alloy is only relevant if it allows the use of large quantities of waste, in particular waste from end-of-life vehicles. Usually, end-of-life vehicles are crushed and then various separation processes, known to those skilled in the art, are implemented to sort the product obtained by crushing. One of the products obtained by said separation is twitch, a typical composition of which is given in Table 2.

[0019] There is therefore a need to recycle scraps and waste in the form of twitch to produce bodywork sheets for the automotive industry which have properties suitable for use on a vehicle.

[0020] Problem posed

[0021] The problem to be solved is to develop an aluminum alloy that aims for an excellent compromise between mechanical strength, its formability, its resistance to corrosion, its manufacturing suitability while being produced with a maximum of post-consumer waste in twitch.

[0022] In practice, the aim is to obtain an alloy whose yield strength (Rp0.2) is similar to the alloys currently used in order to have a comparable elastic return during shaping. The alloy must have an Ag% elongation at least similar to the alloys currently used, preferably at least 20% in order to manufacture comparable parts. The alloy must have, after bake hardening, an yield strength (Rp0.2) comparable to the alloys currently used in order to obtain the same mechanical performance on vehicles, preferably superior. Corrosion resistance must be at least comparable to that of the alloys currently used. Examples of alloys currently used are examples J, K and L mentioned below.

[0023] Subject of the invention

[0024] A first object of the invention is an aluminum alloy of composition, in % by weight:

[0025] If: about 1.7% - about 7.0%,

[0026] Fe: about 0.2% - about 0.8%,

[0027] Cu: about 0.3% - about 1.0%,

[0028] Mn: about 0.2% - about 0.6%,

[0029] Mg: about 0.2% - about 0.6%,

[0030] Zn: about 0.2% - about 0.6%,

[0031] Ti, Cr, Sn, Pb, Zr, V, Sr, Ni: <= about 0.1%, other elements: each <=0.05%, together <=0.15%, remainder: AL A second subject of the invention is a rolled alloy product according to the invention.

[0032] A third subject of the invention is a method for manufacturing a product according to the invention comprising the successive steps: a) Supply of aluminum alloys and addition metals, the aluminum alloys being at least 20% in the form of post-consumer waste, b) Optionally sorting of the post-consumer waste, c) Production of an alloy according to any one of claims 1 to 8, from the aluminum alloys comprising optionally sorted post-consumer waste and supplied addition metals d) Casting of the alloy from a raw form, preferably by semi-continuous vertical casting, e) Homogenization and / or reheating of the raw form, f) Hot and optionally cold deformation by rolling of the raw form, g) Solution treatment then quenching of the raw form thus deformed, h) Optionally pre-tempering typically at a pre-tempering temperature of 60 to 120°C for a duration of 1 to 24 hours,i) Maturation preferably from 24 hours to 6 months.,

[0033] A fourth object of the invention is the use of a product according to the invention for the manufacture of parts for motor vehicles.

[0034] Description of figures

[0035] [Fig. 1]: This figure shows the LDH as a function of recyclability.

[0036] [Fig. 2]: This figure shows the Ag% elongation in the T4 state as a function of the cracking tendency during cold rolling (crackability).

[0037] [Fig. 3]: This figure shows the trade-off between LDH and yield strength at T4.

[0038] [Fig. 4]: This figure shows describes the LDH measuring tool.

[0039] [Fig. 5]: This figure shows the work hardening coefficient as a function of the recycling suitability.

[0040] Description of the invention

[0041] All aluminum alloys referred to below are designated, unless otherwise stated, according to the rules and designations defined by the Aluminum Association in the Registration Record Series it publishes regularly. Unless otherwise stated, compositions are expressed in % by weight. The expression 1.4 Cu means that the copper content expressed in % by weight is 1.4%. The alloy groups, also called series, are defined in EN 573-1 (2005). The metallurgical conditions referred to are designated according to European standard EN-515. In particular, a product in the solution-treated and quenched state is known to the person skilled in the art as obtained by heating an alloy to a certain temperature for a sufficient time to allow one or more of the constituents to enter the solid solution, where they remain in a supersaturated state after quenching.In particular, a tempered or aged product is known to the person skilled in the art as obtained by a treatment of a metal aimed at modifying its properties by precipitation of intermetallic phases from the supersaturated solution. Aging can be obtained by a heat treatment (tempering or artificial aging) or at room temperature (natural aging). The pre-tempered state is not standardized in the standard but is well known to the person skilled in the art who sometimes designates it as T4p or T4*. This is a heat treatment after quenching which stabilizes the product by limiting natural aging while improving the response of the product during paint baking, during the manufacture of an automobile, which is a tempering in terms of metallurgy.

[0042] The static mechanical characteristics in tension, in other words the breaking strength Rm, the conventional elastic limit at 0.2% elongation Rp0.2, the elongation at necking Ag% and the elongation at break A%, are determined by a tensile test according to standard NF EN ISO 6892-1, the sampling and the direction of the test being defined by standard EN 485-1.

[0043] The bending angles, called alpha, are determined by 3-point bending test according to standard NF EN ISO 7438 and procedures VDA 238-100 and VDA 239-200 version 2017.

[0044] Unless otherwise stated, the definitions of EN 12258 apply.

[0045] The LDH parameter is widely used to evaluate the formability of sheet metal. It has been the subject of numerous publications, including R. Thompson, “The LDH test to evaluate sheet metal formability - Final Report of the LDH Committee of the North American Deep Drawing Research Group”, SAE conference, Detroit, 1993, SAE Paper No. 930815. This is a stamping test of a blank held peripherally by a retaining ring. The blank-holding pressure is adjusted to prevent slippage in the retaining ring. The blank, measuring 120 mm x 160 mm, is loaded in a mode close to plane deformation. The punch used is hemispherical. Figure 4 specifies the dimensions of the tools used to perform this test. Lubrication between the punch and the sheet is provided by graphite grease. The punch descent speed is 50 mm / min. The so-called LDH value is the value of the punch displacement at break, i.e. the limit depth of the drawing.It actually corresponds to the average of three tests, giving a 95% confidence interval on the measurement of 0.2 mm.

[0046] The tensile strain hardening coefficient is measured according to the ISO 10275 2020-08 standard.

[0047] Unless otherwise stated, the definitions of EN 12258-1 (1998) apply.

[0048] Unless otherwise stated, the definitions in EN 12258-3 (2003) apply.

[0049] Pure or alloyed aluminum in the form of primary metal ingot generally has the disadvantage of generating significant CO2 emissions during its manufacture, and we therefore try to limit its use. Regarding other sources of metal, we distinguish between pre-consumer manufacturing scrap, which is generated before the metal is delivered to the end customer: the window buyer, the vacuum chamber user, the car buyer, the airline, etc., and post-consumer waste, which is recovered after use of the product, typically from the car at the scrapyard, in a sorting center. The manufacturing stages of aluminum products generate numerous pre-consumer manufacturing scraps during all stages.Examples of post-consumer waste include cast plate ends that have been dropped before hot working, rolled or extruded product ends that have been dropped during the sheet metal or profile manufacturing process, blank skeletons used for stamping, machining chips, etc. Examples of post-consumer waste include used window frames, scrapped car parts, crushed cars, dismantled aircraft, etc. Post-consumer waste can be supplied raw, in compacted form, or optionally after being melted separately and possibly solidified. Additional elements are also supplied in suitable forms. These can be elements in their metallic form or in an alloyed form.

[0050] Unless otherwise stated, the definitions of the ISRI (Institute of Scrap Recycling Industries) "Scrap Specification Circular 2022" apply. In particular, twitch is defined as aluminum waste or scrap fragmented by automotive shredders.

[0051] The twitch is derived from the wet or dry media separation device, the material is dry and contains no more than 1% maximum free zinc, 1% maximum free magnesium and 1% maximum analytical iron. It contains no more than 2% total non-metallic materials, including no more than 1% rubber and plastic. It is free from excessively oxidized materials, airbag cartridges or any sealed or pressurized articles.

[0052] Room temperature is any temperature compatible with human work from 5 to 35°C. Room temperature can be a temperature of 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C. The term "approximately," when used in connection with a measurable numerical variable, refers to the stated value of the variable and all values ​​of the variable that are within the experimental error of the stated value or within ±10 percent of the stated value, whichever is greater.

[0053] Detailed description

[0054] The invention is based on the observation made by the applicant that it is entirely possible, thanks to a suitable composition and manufacturing process, to produce sheets from the recycling of post-consumer aluminium waste having an acceptable aptitude for stamping, good resistance to corrosion and mechanical properties particularly suited to the production of automobile bodywork.

[0055] The concentration ranges imposed on the constituent elements of this type of alloy are therefore explained by the following reasons:

[0056] Si: The Si content is about 1.7% to about 7.0%. Increasing the Si content facilitates the use of recycled products and especially twitch. Mg2Si or MgsSig precipitates contribute to the hardening of the alloy during tempering, for example during paint baking. Excess Si degrades hot and cold rolling ability by causing edge cracks that reduce the usable width of a rolled sheet or even cause it to break during fabrication. Excess Si relative to Mg contributes to formability in the T4 temper. Si contributes to strain rate sensitivity.

[0057] A compromise of these properties with recycling is advantageously Si >= 2.0%, preferably Si >= 2.2%, more preferably Si >= 2.5%, more preferably Si >=2.8% and / or Si <= 6%, preferably Si <= 5%, more preferably Si <= 4.3%, more preferably Si <=4.1%.

[0058] In one embodiment, the mass content of Si is at least about 1.90%, and at most about 2.10% or at most about 2.30% or at most about 2.50% or at most about 2.70% or at most about 2.90% or at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 2.10%, and at most about 2.30% or at most about 2.50% or at most about 2.70% or at most about 2.90% or at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 2.30%, and at most about 2.50% or at most about 2.70% or at most about 2.90% or at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 2.50%, and at most about 2.70% or at most about 2.90% or at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 2.70%, and at most about 2.90% or at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 2.90%, and at most about 3.10% or at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 3.10%, and at most about 3.30% or at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 3.30%, and at most about 3.50% or at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 3.50%, and at most about 3.70% or at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 3.70%, and at most about 3.90% or at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 3.90%, and at most about 4.10% or at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 4.10%, and at most about 4.30% or at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 4.30%, and at most about 4.50% or at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 4.50%, and at most about 4.70% or at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 4.70%, and at most about 4.90% or at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 4.90%, and at most about 5.10% or at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 5.10%, and at most about 5.30% or at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 5.30%, and at most about 5.50% or at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 5.50%, and at most about 5.70% or at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 5.70%, and at most about 5.90% or at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%.In one embodiment, the mass content of Si is at least about 5.90%, and at most about 6.10% or at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 6.10%, and at most about 6.30% or at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 6.30%, and at most about 6.50% or at most about 6.70%. In one embodiment, the mass content of Si is at least about 6.50%, and at most about 6.70%.

[0059] Fe: The Fe content is about 0.2% to about 0.8%. Increasing the Fe content facilitates the use of recycled products because Fe is a pollutant in recycling processes. A very low Fe content requires diluting the products to be recycled with expensive alloys with a low Fe content. Fe degrades the hot and cold rolling ability by causing edge cracks that reduce the usable width of a rolled sheet or even cause it to break during manufacturing. Excess Fe makes the product unsuitable for forming, particularly because the bending ability may be degraded.

[0060] A compromise of these properties with recycling is advantageously Fe >= 0.25%, preferably Fe >=0.30%, more preferably Fe >= 0.33%, more preferably Fe >=0.35%, more preferably Fe >=0.37% and / or Fe <= 0.75%, preferably Fe <=0.65%, more preferably Fe <= 0.55%, more preferably Fe <=0.50%, more preferably Fe <=0.45%.

[0061] In one embodiment, the mass content of Fe is at least about 0.20%, and at most about 0.30% or at most about 0.40% or at most about 0.50% or at most about 0.60% or at most about 0.70% or at most about 0.80%. In one embodiment, the mass content of Fe is at least about 0.30%, and at most about 0.40% or at most about 0.50% or at most about 0.60% or at most about 0.70% or at most about 0.80%. In one embodiment, the mass content of Fe is at least about 0.40%, and at most about 0.50% or at most about 0.60% or at most about 0.70% or at most about 0.80%. In one embodiment, the mass content of Fe is at least about 0.50%, and at most about 0.60% or at most about 0.70% or at most about 0.80%. In one embodiment, the mass content of Fe is at least about 0.60%, and at most about 0.70% or at most about 0.80%.In one embodiment, the mass content of Fe is at least about 0.70%, and at most about 0.80%.

[0062] Cu: The Cu content is approximately 0.3% to approximately 1.0%. Increasing the Cu content facilitates the use of recycled products, particularly twitch. Copper is an element involved in hardening precipitation, which is beneficial for increasing the yield strength in the T4 state and after curing of paints. In the T4 state, Cu in solid solution promotes formability and increases work hardening. Cu impairs hot and cold rolling ability by causing edge cracks that reduce the usable width of a rolled sheet or even cause it to break during manufacturing. In addition, a Cu content greater than approximately 1% hardens too much and then impairs formability, particularly bendability. Cu is known to impair corrosion resistance; surprisingly, corrosion resistance is acceptable despite the Cu content according to the invention.

[0063] A compromise of these properties with recycling is advantageously Cu >=0.35%, preferably Cu >= 0.43%, preferably Cu >=0.45%, more preferably Cu >= 0.48%, more preferably Cu >=0.50%, and / or Cu <= 0.98%, preferably Cu <=0.97%.

[0064] In one embodiment, the mass content of Cu is at least about 0.35%, and at most about 0.45% or at most about 0.55% or at most about 0.65% or at most about 0.75% or at most about 0.85% or at most about 0.95%. In one embodiment, the mass content of Cu is at least about 0.45%, and at most about 0.55% or at most about 0.65% or at most about 0.75% or at most about 0.85% or at most about 0.95%. In one embodiment, the mass content of Cu is at least about 0.55%, and at most about 0.65% or at most about 0.75% or at most about 0.85% or at most about 0.95%. In one embodiment, the mass content of Cu is at least about 0.65%, and at most about 0.75% or at most about 0.85% or at most about 0.95%. In one embodiment, the mass content of Cu is at least about 0.75%, and at most about 0.85% or at most about 0.95%.In one embodiment, the mass content of Cu is at least about 0.85%, and at most about 0.95%.

[0065] Mn: The Mn content is about 0.2% to about 0.6%. Increasing the Mn content facilitates the use of recycled products and especially twitch. Manganese can contribute to common intermetallic precipitates and dispersoids. Mn can degrade formability in the T4 temper due in particular to the increase in the intermetallic fraction and the decrease in work hardening capacity at high strains.

[0066] A compromise of these properties with recycling is advantageously Mn => 0.20%, preferably Mn >= 0.21%, preferably Mn >=0.22%, and / or Mn <= 0.55%, preferably Mn <=0.52%, more preferably Mn <= 0.50%, more preferably Mn <=0.47%, more preferably Mn <=0.45%, more preferably Mn <=0.43%, more preferably Mn <=0.41%, more preferably Mn <=0.39%, more preferably Mn <=0.37%, more preferably Mn <=0.35%, more preferably Mn <=0.33%.

[0067] In one embodiment, the mass content of Mn is at least about 0.20%, and at most about 0.30% or at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mn is at least about 0.30%, and at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mn is at least about 0.40%, and at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mn is at least about 0.50%, and at most about 0.60%.

[0068] Mg: The Mg content is about 0.2% to about 0.6%. Increasing the Mg content facilitates the use of recycled products and especially twitch. Mg2Si precipitates contribute to the hardening of the alloy during tempering, for example during paint baking. The excess of Si relative to Mg is favorable to formability in the T4 temper. The presence of Mg increases the yield strength in the T4 temper and therefore makes forming more difficult.

[0069] A compromise of these properties with recycling is advantageously Mg >= 0.22%, preferably Mg >=0.25%, more preferably Mg >= 0.27%, more preferably Mg >=0.32%, more preferably Mg >=0.35% and / or Mg <= 0.55%, preferably Mg <=0.52%, more preferably Mg <= 0.50%, more preferably Mg <=0.47%, more preferably Mg <=0.45%. In one embodiment, the mass content of Mg is at least about 0.20%, and at most about 0.30% or at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mg is at least about 0.30%, and at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mg is at least about 0.40%, and at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Mg is at least about 0.50%, and at most about 0.60%.

[0070] Zn: The content is about 0.2% to about 0.6%. Increasing the Zn content facilitates the use of recycled products and in particular twitch. Since Zn is an addition element in aluminum alloys, it is interesting to accept it for the purpose of recycling aluminum scrap and waste, especially from end-of-life vehicles. Zn hardens the alloy in the T4 state as well as after tempering but degrades its formability in the T4 state.

[0071] A compromise of these properties with recycling is advantageously Zn => 0.20%, preferably => 0.22%, more preferably => 0.24%, more preferably => 0.26%, more preferably => 0.28%n more preferably => 0.30%, more preferably => 0.32% and / or Zn <= 0.56%, preferably <=0.54%, more preferably <=0.52%.

[0072] In one embodiment, the mass content of Zn is at least about 0.20%, and at most about 0.30% or at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Zn is at least about 0.30%, and at most about 0.40% or at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Zn is at least about 0.40%, and at most about 0.50% or at most about 0.60%. In one embodiment, the mass content of Zn is at least about 0.50%, and at most about 0.60%.

[0073] Cr: The Cr content is at most about 0.1% by weight. Increasing the Cr content facilitates the use of recycled products and in particular twitch. In some cases it can be added to refine the grains and stabilize the structure. Decreasing the Cr content generally improves the formability measured with LDH. In some cases the present inventors have surprisingly found that a maximum Cr content of 0.08%, advantageously 0.05% and preferably 0.03% does not prevent the recycling of significant quantities of scrap from the automotive industry, in particular twitch.

[0074] A compromise of these properties with recycling is a Cr content of at most 0.08% and / or preferably >= 0.01%. In one embodiment, the mass content of Cr is at least about 0.01%, and at most about 0.02% or at most about 0.03% or at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.02%, and at most about 0.03% or at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.03%, and at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%.In one embodiment, the mass content of Cr is at least about 0.04%, and at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.05%, and at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.06%, and at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.07%, and at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Cr is at least about 0.08%, and at most about 0.09% or at most about 0.10%.In one embodiment, the mass content of Cr is at least about 0.09%, and at most about 0.10%.

[0075] Ti: A maximum content of approximately 0.1%, preferably 0.10%, is required to avoid the conditions for the formation of primary phases during vertical casting, which have a detrimental effect on all of the claimed properties. Increasing the Ti content facilitates the use of recycled products and in particular twitch. In one embodiment, the Ti content is at least approximately 0.01%.

[0076] In one embodiment, the mass content of Ti is at least about 0.01%, and at most about 0.02% or at most about 0.03% or at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.02%, and at most about 0.03% or at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.03%, and at most about 0.04% or at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%.In one embodiment, the mass content of Ti is at least about 0.04%, and at most about 0.05% or at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.05%, and at most about 0.06% or at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.06%, and at most about 0.07% or at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.07%, and at most about 0.08% or at most about 0.09% or at most about 0.10%. In one embodiment, the mass content of Ti is at least about 0.08%, and at most about 0.09% or at most about 0.10%.In one embodiment, the mass content of Ti is at least about 0.09%, and at most about 0.10%.

[0077] Sn, Pb, Zr, V, Sr, Ni: The maximum content of each of these elements is approximately 0.1%, preferably 0.10%. Increasing the content of each of these elements facilitates the use of recycled products and in particular twitch. In one embodiment, the content of each of these elements is at least approximately 0.01%. In one embodiment, the content of each of these elements is at least about 0.01%, or is at least about 0.02%, or is at least about 0.03%, or is at least about 0.04%, or is at least about 0.05%, or is at least about 0.06%, or is at least about 0.07%, or is at least about 0.08%, and / or is at most about 0.09%, or is at most about 0.08%, or is at most about 0.07%, or is at most about 0.06%, or is at most about 0.05%, or is at most about 0.04%, or is at most about 0.03%, or is at most about 0.02%.

[0078] In certain cases, the present inventors have surprisingly found that a maximum Ni content of 0.08%, advantageously 0.05%, preferably 0.03%, does not prevent the recycling of significant quantities of scrap from the automotive industry, in particular twitch.

[0079] The other elements are typically impurities whose content is kept less than or equal to 0.05%, preferably strictly less than 0.05%, the whole being less than 0.15%, the remainder being aluminum.

[0080] In one embodiment the alloy according to the invention comprises at least 20% or at least 30% or at least 40% or at least 50% or at least 60% or at least 70% or at least 80% or at least 90% of post-consumer waste or at least, preferably from end-of-life motor vehicles, more preferably from aluminum fragmented by automotive shredders. In an advantageous embodiment the composition of the alloy according to the invention is:

[0081] If: 1.7% - 7.0%,

[0082] Fe: 0.2% - 0.8%,

[0083] Cu: 0.3% - 1.0%,

[0084] Mn: 0.2% -0.35%,

[0085] Mg: 0.2% -0.6%,

[0086] Zn: 0.2% -0.6%,

[0087] Ti, Sn, Pb, Zr, V, Sr: <= 0.1%,

[0088] Cr <= 0.08%,

[0089] Ni <= 0.08% other elements: each < =0.05%, together < = 0.15%, remainder: Al.

[0090] In another advantageous embodiment, the composition of the alloy according to the invention is:

[0091] If: 1.7% - 7.0%,

[0092] Fe: 0.2% - 0.8%,

[0093] Cu: 0.40% - 1.0%,

[0094] Mn: 0.2% -0.6%,

[0095] Mg: 0.2% -0.6%,

[0096] Zn: 0.2% -0.6%,

[0097] Ti, Sn, Pb, Zr, V, Sr: <= 0.1%,

[0098] Cr <= 0.08%,

[0099] Ni <= 0.08%, other elements: each < =0.05%, together < = 0.15%, remainder: Al.

[0100] In another advantageous embodiment, the composition of the alloy according to the invention is:

[0101] If: 2.8% - 3.2% preferably 2.8% - 3.0%,

[0102] Fe: 0.30%- 0.45%, preferably the minimum is 0.35% and / or preferably the maximum 0.40%,

[0103] Cu: 0.50% - 0.65%, preferably the minimum is 0.55% and / or preferably the maximum is 0.60%,

[0104] Mn: 0.2%-0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%,

[0105] Mg: 0.30% -0.45%, preferably the minimum is 0.35% and / or preferably the maximum is 0.40%, Zn: 0.25%- 0.40%, preferably the minimum is 0.30% and / or preferably the maximum is 0.35%,

[0106] Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, preferably 0.08%.

[0107] The above embodiment has a compromise between the properties of being less hard after baking the paints, by more formability and bendability, by less cracking during rolling, by a little more corrosion and by a lesser suitability for recycling.

[0108] The embodiment below has a compromise between the properties by being harder baking paints, by less formability and bendability, by better corrosion resistance, by a little more crackability during rolling and by better suitability for recycling.

[0109] In another advantageous embodiment, the composition of the alloy according to the invention is: Si: 3.7% -4.1%, preferably 3.9% - 4.1%,

[0110] Fe: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%,

[0111] Cu: 0.70% - 1%, preferably the minimum is 0.80% and / or preferably the maximum is 0.97%,

[0112] Mn: 0.2%- 0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%,

[0113] Mg: 0.30% 0.45%, preferably, preferably the minimum is 0.35%-and / or preferably the maximum is 0.40%,

[0114] Zn: 0.45% - 0.60%, preferably, preferably the minimum 0.50% is and / or preferably the maximum is 0.55%,

[0115] Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, more preferably 0.08%,

[0116] Cr <= 0.08%,

[0117] Ni <= 0.08%, other elements: each < =0.05%, together < = 0.15%, remainder: AL

[0118] The embodiment below allows some tolerance to Cu contamination, which often occurs in the form of electrical wiring, while limiting hardness, increasing formability and bendability compared to the composition cited just above by reducing the Si and Zn content.

[0119] In another advantageous embodiment the composition of the alloy according to the invention is: Si: 3.0% - 3.6%, preferably the minimum is 3.2% and / or preferably the maximum is 3.8%,

[0120] Fe: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%,

[0121] Cu: 0.70%- 1%, preferably the minimum is 0.80% and / or preferably the maximum is 0.97%,

[0122] Mn: 0.2%- 0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%,

[0123] Mg: 0.30%-0.45%, preferably the minimum is 0.35% and / or preferably the maximum is 0.40%,

[0124] Zn: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%,

[0125] Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, more preferably 0.08%,

[0126] Cr <= 0.08%,

[0127] Ni <= 0.08%, other elements: each < =0.05%, together < = 0.15%, remainder: Al.

[0128] The invention also relates to rolled alloy products according to the invention.

[0129] In an advantageous embodiment, the rolled products according to the invention are in the solution-treated, quenched and pre-tempered or solution-treated, quenched and tempered state. These states allow the alloy to harden during the baking of the paints. Pre-tempering allows the alloy to be stabilized during natural aging or maturation periods of storage before the alloy is used.

[0130] The products according to the invention have an advantageous rolling deformation capacity. The rolling capacity is considered satisfactory in particular when few cracks or cracks of short length form during rolling, that is to say in particular when the tendency to crack during cold rolling is low. By carrying out cold rolling tests as described in the example, a crackability is measured in mm corresponding to the maximum length of the cracks formed, in the cross-rolling direction, after cold rolling in 6 passes from a hot-rolled thickness of 6 mm up to a thickness of 1 mm. The rolled products according to the invention advantageously have a crackability less than or equal to 5 mm, preferably less than or equal to 4 mm, more preferably less than or equal to 3 mm.

[0131] In one embodiment, the rolled product according to the invention has an LDH greater than or equal to 7.5 mm, preferably greater than or equal to 28.0 mm, more preferably greater than or equal to 28.5 mm, more preferably greater than or equal to 28.7 mm. Increasing the LDH value makes it possible to improve the formability during stamping.

[0132] In one embodiment, the rolled product according to the invention has a minimum yield strength RpO,2 in the T4 state of 70 MPa, preferably 80 MPa, more preferably 90 MPa and / or has a maximum yield strength RpO,2 in the T4 state of 140 MPa, preferably 130 MPa, more preferably 120 MPa. Too low a yield strength in the T4 state will limit the yield strength after baking the paints. Too high a yield strength in the T4 state increases the drawing force. Limiting the maximum yield strength in the T4 state is a compromise that improves the formability measured with the LDH. In one embodiment, the yield strength RpO,2 in the T4 state is at least 80 MPa and at most 100 MPa. This embodiment is a compromise which makes it possible to increase the formability and the ability to deform hot and cold without the formation of cracks.In another embodiment, the yield strength RpO,2 in the T4 state is at least 105 MPa and at most 125 MPa. This embodiment is a compromise which makes it possible to increase the recyclability.

[0133] In one embodiment, the rolled product according to the invention has a minimum post-paint curing yield strength RpO,2 of 200 MPa, preferably 210 MPa, and / or a maximum post-paint curing yield strength RpO,2 of 260 MPa, preferably 250 MPa. Increasing the post-paint curing yield strength is advantageous for reducing the thickness of the parts. In one embodiment, the post-paint curing yield strength is at least 225 MPa, preferably 235 MPa. This embodiment is a compromise which also increases the recyclability.

[0134] Surprisingly, the composition according to the invention makes it possible to obtain a work hardening coefficient comparable to the reference alloys while increasing the suitability for recycling.

[0135] The manufacturing process of rolled products includes the successive stages: supply, optionally sorting, alloying, casting, homogenization and / or reheating, hot and optionally cold deformation, solution treatment and quenching, optionally pre-tempering, and maturation.

[0136] The supply of aluminium alloys and additional metals is carried out, the aluminium alloys being at least 20%, preferably at least 30%, preferably at least 40%, preferably at least 50%, preferably at least 60%, preferably at least 70% in the form of post-consumer waste.

[0137] Post-consumer waste is preferably at least 20%, preferably at least 30%, preferably at least 40%, preferably at least 50%, preferably at least 60%, preferably at least 70% in the form of aluminum fragmented by automotive or twitch shredders.

[0138] Optionally, post-consumer waste is sorted. In an advantageous embodiment, post-consumer waste is crushed, separated by sieving and waste larger than 1 cm is sorted between alloy families, the analysis being advantageously carried out by LIBS (Laser Induced Breakdown Spectroscopy) or by XRT (X-Ray Transmission).

[0139] An alloy according to the invention is produced from aluminum alloys comprising optionally sorted post-consumer waste and sourced addition metals.

[0140] A raw form is cast with an alloy according to the invention. Preferably, the casting is carried out by semi-continuous vertical casting, with direct cooling (DC Casting). For hot deformation by rolling, the raw form is advantageously a rolling plate, typically at least 250 mm thick.

[0141] The raw form is homogenized and / or reheated typically to a temperature above the solvus temperature of the alloy, while avoiding local melting or burning for a period of at least 2 hours, preferably 3 hours, more preferably 4 hours and at most 7 hours, preferably 6 hours, more preferably 5 hours. The homogenization and / or reheating temperature is preferably at most 560°C, preferably 550°C, more preferably 540°C, more preferably 530°C, and at least 490°C, preferably 500°C. Too high or too low a temperature degrades the mechanical properties of the product.

[0142] The raw form is deformed hot and optionally cold by rolling.

[0143] In one embodiment the raw form, in the form of a rolling plate, is hot rolled typically to a thickness of 3 to 8 mm. The hot rolling start temperature is typically 450°C to 550°C. Optionally the rolled product obtained after hot rolling is cold rolled to a thickness typically of 0.5 to 4 mm. In one embodiment the thickness is 0.7 to 3 mm. In one embodiment the thickness is 0.9 to 2 mm.

[0144] The raw form thus deformed is put into solution then quenched.

[0145] Solution treatment is typically carried out at a solution temperature above the solvus temperature of the alloy, while avoiding local melting or burning, and then quenched, preferably in a continuous furnace. Too cold a solution treatment and / or too short a solution treatment degrades the mechanical properties of the sheet by insufficient solution treatment. Too hot a solution treatment causes burns degrading the mechanical properties. Too long a solution treatment degrades productivity. Preferably, solution treatment lasts from 15 seconds to 300s. The solution treatment temperature is preferably a maximum of 560°C, preferably 550°C, more preferably 540°C, more preferably 530°C, and a minimum of 490°C, preferably 500°C.

[0146] Then the product thus put into solution is quenched typically at a speed of more than 30°C / s and better at least 100°C / s with water or with air or with a successive combination of water or air. Preferably the product is quenched to a temperature of 60 to 100°C. An insufficient cooling speed degrades the mechanical properties of the sheet because the solution treatment is then incomplete.

[0147] Optionally, the product is then reheated to achieve pre-tempering, typically at a pre-tempering temperature of 60°C to 120°C for a period of 1 to 24 hours, preferably 60°C to 100°C for 2 to 16 hours. In the case of rolled products, pre-tempering can be achieved by coiling and then cooling to room temperature, preferably for at least 40 hours. Pre-tempering improves the paint baking response, which is the difference between the yield strength in the T4 state and the yield strength after the paint baking.

[0148] The product obtained then matures at room temperature, preferably between 24 hours and 6 months, preferably between 72 hours and 5 months.

[0149] In one embodiment, the product thus obtained is then subjected to tempering.

[0150] In another embodiment, the product thus obtained is painted and can undergo a heat treatment of baking the paint.

[0151] The product according to the invention is advantageously used for the manufacture of parts for motor vehicles. In one embodiment, the product according to the invention is used as a sheet metal for lining, such as door or hood linings. For certain automotive parts, particularly linings, the thicknesses are between 0.7 and 2.0 mm. A thickness of less than 0.7 mm is too thin to ensure the rigidity of the component containing the lining. A thickness greater than 2.0 mm makes the component containing the lining too heavy for the user and the vehicle. In one embodiment, the product according to the invention is used as a structural part, such as top hat stiffeners. In one embodiment, the product according to the invention is used as a battery tray element, in particular as a battery tray bottom.For battery tray bottoms, thicknesses are typically between 1.5 and 4.0 mm and preferably between 2 and 3 mm. Examples.

[0152] The disclosure is further illustrated by the following examples. These examples are intended only to illustrate the invention and not to limit it.

[0153] Different alloys were tested in the laboratory according to the compositions in Table 1. They were cast by vertical semi-continuous casting (direct chill casting) in ingots of thickness 50 mm after scalping. Alloys J, K and L are examples of alloys of the 6XXX series used for sheets for applications in the automotive industry. The examples according to the invention, C and D, are identified "E" and the counter-examples by "CE" in Table 1. The compositions in Table 1 are in % by weight, the other elements are each < = 0.05%, together < = 0.15% the remainder is aluminum. [Table 1]

[0154] The recyclability of these alloys was evaluated using a representative twitch composition according to Table 2. [Table 2]

[0155] The recyclability of the different alloys A to L is evaluated by calculating the maximum quantity of the average composition calculated in Table 2 below for each element. A value greater than 100% means that the twitch does not provide the quantity of the element considered, therefore nothing limits the introduction of twitch to produce the alloy for the element considered. A value less than 100% implies that the twitch provides too much of the element considered and that the introduction of twitch must be limited to produce the alloy. It is therefore necessary to take into account only the minimum on all the elements for each alloy evaluated to define its recyclability. Alloys J, K and L are alloys with a lower recyclability of twitch.

[0156] [Table 3]

[0157] The ingots were reheated to 520°C except for references J and L, which were reheated to 560°C, then hot rolled while maintaining a temperature above 300°C.

[0158] The ingots were then cold rolled in 6 passes from the hot rolled thickness of 5 mm to the thickness of 1 mm except for references J and L which were cold rolled from the hot rolled thickness of 7 mm. The cracking tendency during cold rolling was evaluated by measuring the crack length in the edges in the transverse direction which will be called "crackability". The crack length was measured on the edges after cold rolling to 1 mm and the results are given in Table 4. [Table 4]

[0159] Samples were taken at a thickness of 3 mm. These samples were dissolved for 10 s at a temperature of 510°C (560°C for references J and L), then quenched in water and then pre-tempered for 8 hours at 80°C. These samples were then characterized in the T4 state or after simulation of the painting firing for 20 minutes at 180°C (BH). The results are in Table 5.

[0160] The static mechanical characteristics in tension were measured in the cross direction of rolling.

[0161] The LDH was measured in the cross-rolling direction. The bending, alpha, was characterized with the bending axis parallel to the rolling direction.

[0162] Intergranular corrosion in an acidic environment was measured according to ISO 11846.

[0163] The results are presented in Table 5. [Table 5]

[0164] Figures 1 to 3 show that examples of the invention C and D in particular present the best compromise between the suitability for recycling, the suitability for transformation evaluated by cracks and the suitability for shaping (LDH) and the mechanical properties of elastic limit and elongation in the T4 state.

[0165] The tensile strain hardening coefficient n 4-6 was characterized on 3 mm thick samples in T4 condition. Examples C and D have a better coefficient similar to reference products J, K and L and better than the other examples.

Claims

Tl CLAIMS 1. Aluminum alloy of composition, in % by weight: If: about 1.7% - about 7.0%, Fe: about 0.2% - about 0.8%, Cu: about 0.3% - about 1.0%, Mn: about 0.2% - about 0.6%, Mg: about 0.2% - about 0.6%, Zn: about 0.2% - about 0.6%, Ti, Cr, Sn, Pb, Zr, V, Sr, Ni: <= about 0.1%, other elements: each <=0.05%, together <=0.15%, remainder: Al.

2. Alloy according to the preceding composition claim, in % by weight: If: 1.7% - 7.0%, Fe: 0.2% - 0.8%, Cu: 0.3% - 1.0%, Mn: 0.2% -0.35%, Mg: 0.2% -0.6%, Zn: 0.2% -0.6%, Ti, Sn, Pb, Zr, V, Sr: <= 0.1%, Cr <= 0.08%, Ni <= 0.08% other elements: each < =0.05%, together < = 0.15%, remainder: Al.

3. Alloy according to one of the preceding claims, characterized in that Si >= 2.0%, preferably Si >= 2.2%, more preferably Si >= 2.5%, more preferably Si >=2.8% and / or Si <= 6%, preferably Si <= 5%, more preferably Si <= 4.3%, more preferably Si <=4.1%.

4. Alloy according to one of the preceding claims, characterized in that Fe >= 0.25%, preferably Fe >=0.30%, more preferably Fe >= 0.33%, more preferably Fe >=0.35%, more preferably Fe >=0.37% and / or Fe <= 0.75%, preferably Fe <=0.65%, more preferably Fe <=0.55%, more preferably Fe <=0.50%, more preferably Fe <=0.45%.

5. Alloy according to one of the preceding claims, characterized in that Cu >= 0.43%, preferably Cu >=0.45%, more preferably Cu >= 0.48%, more preferably Cu >=0.50%, more preferably Cu >=0.35% and / or Cu <= 0.98%, preferably Cu <=0.97%, more preferably Cu <= 0.95%, more preferably Cu <=0.92%, more preferably Cu <=0.90%.

6. Alloy according to one of the preceding claims, characterized in that Mg >= 0.22%, preferably Mg >=0.25%, more preferably Mg >= 0.27%, more preferably Mg >=0.32%, more preferably Mg >=0.35% and / or Mg <= 0.55%, preferably Mg <=0.52%, more preferably Mg <= 0.50%, more preferably Mg <=0.47%, more preferably Mg <=0.45%.

7. Alloy according to one of the preceding claims, characterized in that Mn => 0.20%, preferably Mn >= 0.21%, preferably Mn >=0.22%, more preferably Mn >= 0.23%, more preferably Mn >=0.24%, more preferably Mn >=0.25% and / or Mn <= 0.55%, preferably Mn <=0.52%, more preferably Mn <= 0.50%, more preferably Mn <=0.47%, more preferably Mn <=0.45%, more preferably Mn <=0.43%, more preferably Mn <=0.41%, more preferably Mn <=0.39%, more preferably Mn <=0.37%, more preferably Mn <=0.35%, more preferably Mn <=0.33%.

8. Alloy according to one of the preceding claims, characterized in that If: 2.8% - 3.2% preferably 2.8% - 3.0%, Fe: 0.30%- 0.45%, preferably the minimum is 0.35% and / or preferably the maximum 0.40%, Cu: 0.50% - 0.65%, preferably the minimum is 0.55% and / or preferably the maximum is 0.60%, Mn: 0.2%-0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%, Mg: 0.30% -0.45%, preferably the minimum is 0.35% and / or preferably the maximum is 0.40%, Zn: 0.25%- 0.40%, preferably the minimum is 0.30% and / or preferably the maximum is 0.35%, Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, preferably 0.08%.

9. Alloy according to one of the preceding claims, characterized in that If: 3.7% -4.1%, preferably 3.9%- 4.1%, Fe: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%, Cu: 0.70% - 1%, preferably the minimum is 0.80% and / or preferably the maximum is 0.97%, Mn: 0.2%- 0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%, Mg: 0.30% 0.45%, preferably, preferably the minimum is 0.35%-and / or preferably the maximum is 0.40%, Zn: 0.45% - 0.60%, preferably, preferably the minimum 0.50% is and / or preferably the maximum is 0.55%, Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, more preferably 0.08%, Cr <= 0.08%, Ni <= 0.08%, other elements: each < =0.05%, together < = 0.15%, remainder: Al.

10. Alloy according to one of the preceding claims, characterized in that If: 3.0%- 3.6%, preferably the minimum is 3.2% and / or preferably the maximum is 3.8%, Fe: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%, Cu: 0.70%- 1%, preferably the minimum is 0.80% and / or preferably the maximum is 0.97%, Mn: 0.2%- 0.30%, preferably the minimum is 0.20% and / or preferably the maximum is 0.25%, Mg: 0.30%-0.45%, preferably the minimum is 0.35% and / or preferably the maximum is 0.40%, Zn: 0.35% - 0.50%, preferably the minimum is 0.40% and / or preferably the maximum is 0.45%, Ti, Sn, Pb, Zr, V, Sr: <= 0.10%, more preferably 0.08%, Cr <= 0.08%, Ni <= 0.08%, other elements: each < =0.05%, together < = 0.15%, remainder: Al.

11. Rolled alloy product according to one of claims 1 to 10.

12. Rolled product according to claim 11 in the solution-treated, quenched and pre-tempered state or in the solution-treated, quenched and tempered state.

13. Rolled product according to claim 11 or claim 12 characterized in that the crackability is less than or equal to 5 mm, preferably less than or equal to 4 mm, more preferably less than or equal to 3 mm, the crackability being the maximum length of the cracks formed on the edges of the rolled product, in the cross direction during rolling, after cold rolling in 6 passes from a hot rolled thickness of 6 mm to a thickness of 1 mm.

14. A method of manufacturing a product according to one of claims 11 to 13 comprising the successive steps: a) Supply of aluminum alloys and addition metals, the aluminum alloys being at least 20% in the form of post-consumer waste, b) Optionally sorting of the post-consumer waste, c) Production of an alloy according to any one of claims 1 to 10, from the aluminum alloys comprising optionally sorted post-consumer waste and supplied addition metals, d) Casting of the alloy from a raw form, preferably by semi-continuous vertical casting, e) Homogenization and / or reheating of the raw form, f) Hot and optionally cold deformation by rolling of the raw form, g) Solution treatment then quenching of the raw form thus deformed, h) Optionally pre-tempered typically at a pre-tempered temperature of 60 to 120°C for a period of 1 to 24 hours, i) Maturation preferably from 24 hours to 6 months.

15. Use of a product according to one of claims 11 to 13 for the manufacture of parts for motor vehicles.

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