6XXX ALUMINUM ALLOY WITH IMPROVED RECYCLABILITY

Abstract

The invention relates to AlMgSi alloys particularly favorable to recycling. One object of the invention is an aluminum-based alloy comprising, in % by weight, Mg: 0.2 – 1.5; Si: 0.3 – 2.0; Fe: 0.25 – 1.0; Ti: 0.01 – 0.15; at least one element selected from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os, the content of the element if selected being from 0.003 to 0.20 and preferably from 0.005 to 0.15, Zr: ≤0.15; Mn: ≤1.5; V: ≤0.20; Zn: ≤1.0; Cr: ≤0.25; Cu: ≤1.5; The remaining aluminum and unavoidable impurities are present. The addition of certain elements in small quantities allows for modification of the size and distribution of the intermetallic particles, thus tolerating an increased impurity content, particularly iron. The invention also relates to a heat-treated wrought product comprising an alloy according to the invention and its manufacturing process.The invention is particularly useful for automobile construction, building construction, aircraft construction or industrial construction. Abbreviated figure: Figure 1.

Description

Title of the invention: 6XXX ALUMINUM ALLOY WITH IMPROVED RECYCLABILITY technical field

[0001] The invention relates to an aluminium alloy of the 6XXX family which makes it possible to increase the recycling rate in wrought products of this type of alloy, particularly in the automotive field. EARLIER ART

[0002] Aluminum recycling has the advantage of being both economical and environmentally friendly. Secondary aluminum production requires up to 95% less energy than primary aluminum and reduces CO2 emissions. In an effort to improve the environmental impact of aluminum production, the aluminum industry seeks to maximize the recycled content in its products. However, increasing the recycled content generally leads to an increase in impurity levels, particularly iron content, resulting in higher volume fractions and / or larger sizes of intermetallic particles. These can be detrimental to process times such as homogenization, forming properties such as elongation and formability, and surface properties such as response to anodizing.This difficulty is explained, for example, in the article "Texture control by thermomechanical processing of AA6xxx Al-Mg-Si sheet alloys for automotive applications—a review" in the journal Materials Science and Engineering A336 (2002) 249-262.

[0003] In order to avoid this harmful effect, it may be considered to purify the metal.

[0004] French patent FR2902800 describes a method for manufacturing a reflow block from scrap allowing in particular to purify in iron and silicon the scrap of alloys of the 2XXX series or the 7XXX series, without however removing the addition elements such as zinc, copper and magnesium.

[0005] However, these additional purification steps may prove difficult to implement and costly.

[0006] Patent application WO2015 / 151907 Al also mentions the problem of the impurity content in recycled alloys.

[0007] US patent application US20080175747 describes an alloy in which impurities have little effect on the properties.

[0008] Patent application JP2007169740 A describes an alloy comprising, in % by weight, Si: 0.5 - 1.5%, Mg: 0.2 - 2.0%, and up to Fe: 1.5%, up to Mn: 1.0%, up to Cr: 0.5%, up to Zr: 0.5%, up to V: 0.3%, up to Ti: 0.2%, up to Zn = 1.5%, up to Cu: and containing not less than 0.015% and not more than 0.5% of Bi, Sn, Ga, Co, Ni, Ca, Mo, Be, Pb, and W remains aluminium and impurities.

[0009] Patent application JP2016037632 describes an aluminum alloy sheet containing Mg: 0.2 to 2.0% by mass, Si: 0.3 to 2.0% by mass and Fe: 0.01 to 0.5% by mass and one or both of Ni and Co totaling 0.002 to 0.3% by mass and the remainder Al with unavoidable impurities.

[0010] The problem that the present invention seeks to solve is therefore to propose an alloy that can tolerate an increased content of impurities, in particular iron, and therefore not require additional purification and also to limit the duration of homogenizations. Description of the invention

[0011] A first object of the invention is an aluminum-based alloy comprising, in % by weight, Mg: 0.2-1.5; If: 0.3 - 2.0; Fe: 0.25-1.0; Ti: 0.01-0.15; - at least one element chosen from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os the content of the element if it is chosen being from 0.003 to 0.20 and preferably from 0.005 to 0.15, Zr:<0.15; Mn: <1.5; V: <0.20; Zn: <1.0; Cr: <0.25; Cu: < 1.5; - remains aluminum and unavoidable impurities.

[0012] Another object of the invention is a heat-treated wrought product comprising an alloy according to the invention.

[0013] Yet another object of the invention is a method for manufacturing a heat-treated wrought product according to the invention, comprising the steps of - Supply of pure or alloyed aluminium in the form of primary metal ingots from electrolysis and / or pre-consumer manufacturing scrap and / or post-consumer waste, said waste having optionally been melted separately and possibly solidified and of additive elements in appropriate form; - Creation of a charge with the supplied aluminum, melting of this charging and adding of additives to obtain a liquid metal alloy bath according to the invention, - Casting, preferably by direct-cooling vertical semi-continuous casting of said liquid metal bath to obtain a blank suitable for hot forging, typically a rolling plate, a forging blank or a billet; - Homogenization of the rough draft at a temperature of at least 500 °C; - Hot and optionally cold forging of the blank by rolling, drawing and / or forging to obtain a forged product; - Dissolving the wrought product thus obtained at a temperature of at least 500 °C and quenching; - Aging at room temperature and / or tempering of the wrought product put into solution and quenched thus obtained to obtain a heat-treated wrought product. - Yet another object of the invention is the use of a product according to the invention for automobile construction, building construction, aircraft construction or industrial construction. FIGURES

[0014] Fig. 1 represents the relationship between the size of the intermetallic particles and the distance between the intermetallic particles for the tests in Example 1.

[0015] Figure 2 represents the relationship between the size of the intermetallic particles and the distance between intermetallic particles for the tests in example 2.

[0016] Figure 3 represents the relationship between the size of the intermetallic particles and the distance between intermetallic particles for the tests in example 3.

[0017] Figure 4 represents the relationship between the size of the intermetallic particles and the distance between intermetallic particles for the tests in example 4

[0018] Figure 5 represents a BSE contrast electron microscopy image of intermetallic particles in the tests performed

[0019] Figure 6 represents the image of Figure 5 after a first processing step by image analysis.

[0020] Figure 7 represents the image of Figure 5 after a second processing step by image analysis comprising at least two successive object closure steps enabling the calculation of average sizes and average distances of intermetallic particles.

[0021] Fig. 8 is an optical microscopy image for the tests of Example 5 with addition of La.

[0022] Fig. 9 is an optical microscopy image for the tests of Example 5 without addition of La. DETAILED DESCRIPTION OF THE INVENTION

[0023] Unless otherwise stated, all indications concerning the chemical composition of alloys are expressed as a percentage by weight based on the total weight of the alloy. The expression 1.4 Cu or 1.4 (Cu) means that the copper content expressed as a percentage by weight is multiplied by 1.4. The designation of the alloys is in accordance with the regulations of The Aluminium Association, which are known to those skilled in the art. Unless otherwise stated, the definitions of the metallurgical states of standard EN515-2017 apply.

[0024] The present inventors have found that, surprisingly, the addition of certain elements in small quantities to AlMgSi alloys, also called 6XXX series alloys, makes it possible to modify the size and distribution of intermetallic particles and thus to tolerate an increased content of impurities, in particular iron.

[0025] Intermetallic particles are called compounds containing several metallic or metalloid elements formed during solidification after the formation of face-centered cubic crystalline aluminium such as Al3Fe, Mg2Si, AlFeSi, AlFeMnSi, etc.

[0026] The alloys according to the invention are AlMgSi alloys. Thus they contain from 0.2% to 1.5% of Mg and from 0.3% to 2.0% of Si.

[0027] In one embodiment, the Mg content 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%, or is at least 0.9%, or is at least 1.0%, or is at least 1.1%, or is at least 1.2%, or is at least 1.3%, and / or is at most 1.4%, or is at most 1.3%, 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%, or is at most 0.6%, or is at most 0.5%.

[0028] In one embodiment, the Si content 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%, or is at least 0.9%, or is at least 1.0%, or is at least 1.1%, or is at least 1.2%, or is at least 1.3%, or is at least 1.4%, or is at least 1.5%, or is at least 1.6%, or is at least 1.7%, or is at least 1.8%, and / or is at most 1.9%, or is at most 1.8%, or is at most 1.7%, or is at most 1.6%, or is at most 1.5%, or is at most 1.4%, or is at most 1.3%, 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%, or is at most 0.6%, or is at most 0.5%.

[0029] Copper is an element that can be added to AlMgSi alloys, particularly to improve mechanical properties. The Cu content is at most 1.5% by weight. In one embodiment, the Cu content is 0.05 to 1% by weight. In a in this embodiment, the Cu content is at least 0.10%, or 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%, or is at least 0.50%, or is at least 0.55%, or is at least 0.60%, or is at least 0.65%, or is at least 0.70%, or is at least 0.75%, or is at least 0.80%, or is at least 0.85%, or is at least 0.90%, or is at least 0.95%, or is at least 1.00%, or is at least 1.05%, or is at least 1.10%, or is at least 1.15%, or is at least 1.20%, or is at least 1.25%, or is at least 1.30%, or is at least 1.35%, or is at least 1.40% and / or is at most 1.45%, or is at most 1.40%, or is at most 1.35%, or is at most 1.30%, or is at most 1.25%, or is at most 1.20%, or is at most 1.15%, or is at most 1.10%, or is at most 1.05%, 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%, or is at most 0.45%, or is at most 0.40%, or is at most 0.35%, or is at most 0.30%, or is at most 0.25%, or is at most 0.20%, or is at most 0.15%.

[0030] With regard to the major elements Mg, Si and optionally Cu, the contents of the alloys AA6005, AA6005A, AA6105, AA6205, AA6305, AA6008, AA6009, AA6010, AA6011, AA6111, AA6012, AA6013, AA6014, AA6015, AA6016, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022, AA6023, AA6024, AA6025, AA6026, AA6027, AA6028, AA6031, AA6032, AA6033, AA6040, AA6040, AA6041, AA6042, AA6043, AA6050, AA6151, AA6351, AA6053, AA6055, AA6056, AA6156, AA6060, AA6061, AA6261, AA6361, AA6162, AA6262, AA6063, AA6064, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6082, AA6182, AA6086, AA6091, AA6092, AA6099 are embodiments of the invention.

[0031] The Ti content is from 0.01 to 0.15% by weight. In one embodiment, the Ti content is at least 0.02%, or is at least 0.03%, or is at least 0.04%, or is at least 0.05%, or is at least 0.06%, or is at least 0.07%, or is at least 0.08%, or is at least 0.09%, or is at least 0.10%, or is at least 0.11%, or is at least 0.12%, or is at least 0.13%, and / or is at most 0.14%, or is at most 0.13%, or is at most 0.12%, or is at most 0.11%, or is at most 0.10%, or is at most 0.09%, or is at most 0.08%, or is at most 0.07%, or is at most 0.06%, or is at most 0.05%, or at most 0.04%, or at most 0.03%. The addition of titanium, in the form of metallic titanium and / or TiB2 and / or TiC, is necessary to obtain the desired effect because this addition allows for a grain size that modifies the size and distribution of the intermetallic particles. In an advantageous embodiment, metallic titanium and TiC are added.Advantageously, the addition of TiC is carried out by adding between 0.5 and 2 kg per tonne of metal and preferably between 0.8 kg and 1.2 kg per . tonne of metal of A13%TiO,15%C and / or All%TiO,2%C.

[0032] The Fe content is 0.25 to 1.0% by weight. In one embodiment, the Fe content is at least 0.30%, or is at least 0.35%, or is at least 0.40%, or is at least 0.45%, or is at least 0.50%, or is at least 0.55%, or is at least 0.60%, or is at least 0.65%, or is at least 0.70%, or is at least 0.75%, or is at least 0.80%, or is at least 0.85%, or is at most 0.90%, and / 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%, or is at most 0.45%, or is at most 0.40%, or is at most 0.35%. In one embodiment of the invention, the Fe content is from 0.35 to 0.85% by weight and preferably between 0.4 and 0.7% by weight.

[0033] According to the invention, at least one element selected from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os, the content of the element, if selected, being from 0.003 to 0.20% by weight, is added. The content of an element not selected from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os is less than 0.003% by weight. Advantageously, at least one element selected from Co, Ba, Ni, La, Ce, Ta, the content of the element, if selected, being from 0.003 to 0.20% by weight is added. In one embodiment, the content of the element chosen from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os and preferably from Co, Ba, Ni, La, Ce, Ta is at least 0.004%, or is at least 0.009%, or is at least 0.014%, or is at least 0.019%, or is at least 0.024%, or is at least 0.029%, or is at least 0.034%, or is at least 0.039%, or is at least 0.044%, or is at least 0.049%, or is at least 0.054%, or is at least 0.059%,or is at least 0.064%, or is at least 0.069%, or is at least 0.074%, or is at least 0.079%, or is at least 0.084%, or is at least 0.089%, or is at least 0.094%, or is at least 0.099%, or is at least 0.104%, or is at least 0.109%, or is at least 0.114%, or is at least 0.119%, or is at least 0.124%, or is at least 0.129%, or is at least 0.134%, or is at least 0.139%, or is at least 0.144%, or is at least 0.149%, or is at least 0.154%, or is at least 0.159%, or is at least 0.164%, or is at least 0.169%, or is at least 0.174%, or is at least 0.179%, or is at least 0.184%, or is at least 0.189%, or is at least 0.194% and / or is at most 0.195%, or is at most 0.190%, or is at most 0.185%, or is at most 0.180%, or is at most 0.175%, or is at most 0.170%, or is at most 0.165%, or is at most 0.160%, or is at most 0.155%, or is at most 0.150%, or is at most 0.145%, or is at most 0.140%, or is at most 0.135%, or is at most 0.130%, or at most 0.125%,or is at most 0.120%, or is at most 0.115%, or is at most 0.110%, or is at most 0.105%, or is at most 0.100%, or is at most 0.095%, or is at most 0.090%, or is at most 0.085%, or is at most 0.080%, or is at most 0.075%, or is at most 0.070%, or is , at most 0.065%, or is at most 0.060%, or is at most 0.055%, or is at most 0.050%, or is at most 0.045%, or is at most 0.040%, or is at most 0.035%, or is at most 0.030%, or is at most 0.025%, or is at most 0.020%, or is at most 0.015%, or is at most 0.010%.

[0034] In an advantageous embodiment, at least one element chosen from Co, Ba, Ni, La, Ce, Ta, the content of the element if chosen being from 0.005 to 0.15% by weight is added.

[0035] The Zr content is at most 0.15% by weight. In an advantageous embodiment, the Zr content is from 0.003 to 0.15% by weight. In one embodiment, the Zr content is at least 0.004%, or is at least 0.009%, or is at least 0.014%, or is at least 0.019%, or is at least 0.024%, or is at least 0.029%, or is at least 0.034%, or is at least 0.039%, or is at least 0.044%, or is at least 0.049%, or is at least 0.054%, or is at least 0.059%, or is at least 0.064%, or is at least 0.069%, or is at least 0.074%, or is at least 0.079%, or is at least 0.084%, or is at least 0.089%, or is at least 0.094%, or is at least 0.099%, or is at least 0.104%, or is at least 0.109%, or is at least 0.114%, or is at least 0.119%, or is at least 0.124%, or is at least 0.129%, or is at least 0.134%, or is at least 0.139% and / or is at most 0.145%, or is at most 0.140%, or is at most 0.135%, or is at most 0.130%, or is at most 0.125%, or is at most 0.120%,or is at most 0.115%, or is at most 0.110%, or is at most 0.105%, or is at most 0.100%, or is at most 0.095%, or is at most 0.090%, or is at most 0.085%, or is at most 0.080%, or is at most 0.075%, or is at most 0.070%, or is at most 0.065%, or is at most 0.060%, or is at most 0.055%, or is at most 0.050%, or is at most 0.045%, or is at most 0.040%, or is at most 0.035%, or is at most 0.030%, or is at most 0.025%, or is at most 0.020%, or is at most 0.015%, or at most 0.010%.

[0036] The Mn content is at most 1.5% by weight. In an advantageous embodiment of the invention, the Mn content is from 0.03 to 1.0% by weight. In one embodiment, the Mn content is at least 0.05%, or is at least 0.10%, or 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%, or is at least 0.50%, or is at least 0.55%, or is at least 0.60%, or is at least 0.65%, or is at least 0.70%, or is at least 0.75%, or is at least 0.80%, or is at least 0.85%, or is at least 0.90%, or is at least 0.95%, or is at least 1.00%, or is at least 1.05%, or is at least 1.10%, or is at least 1.15%, or is at least 1.20%, or is at least 1.25%, or is at least 1.30%, or is at least 1.35%, or is at least 1.40% and / or is at most 1.45%, or is at most 1.40%, or is at most 1.35%, or is at most 1.30%, or is at most 1.25%, or is at most 1.20%, or is at most 1.15%, or is at most 1.10%, or is at most 1.05%, 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%, or is at most 0.45%, or is at most 0.40%, or is at most 0.35%, or is at most 0.30%, or is at most 0.25%, or is at most 0.20%, or is at most 0.15%, or is at most 0.10%.

[0037] The V content is at most 0.20% by weight. In one embodiment of the invention, the V content is from 0.05 to 0.20% by weight. In one embodiment, the content of V is at least 0.06%, or is at least 0.07%, or is at least 0.08%, or is at least 0.09%, or is at least 0.10%, or is at least 0.11%, or is at least 0.12%, or is at least 0.13%, or is at least 0.14%, or is at least 0.15%, or is at least 0.16%, or is at least 0.17%, or is at most 0.18%, and / or is at most 0.19%, or is at most 0.18%, or is at most 0.17%, or is at most 0.16%, or is at most 0.15%, or is at most 0.14%, or is at most 0.13%, or is at most 0.12%, or is at most 0.11%, or is at most 0.10%, or is at most 0.09%, or is at most 0.08%, or is at most 0.07%.

[0038] The Zn content is at most 1.0% by weight. In one embodiment, the Zn content is from 0.03 to 1.0% by weight. In one embodiment, the Zn content is at least 0.05%, or is at least 0.10%, or 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%, or is at least 0.50%, or is at least 0.55%, or is at least 0.60%, or is at least 0.65%, or is at least 0.70%, or is at least 0.75%, or is at least 0.80%, or is at least 0.85%, or is at most 0.90%, and / or is at most 0.95%, or is at most 0.90%, or is at most 0.85%, or is at plus 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%, or is at most 0.45%, or is at most 0.40%, or is at most 0.35%, or is at most 0.30%, or is at most 0.25%, or is at most 0.20%, or is at most 0.15%, or is at most 0.10%.

[0039] The Cr content is at most 0.25% by weight. In one embodiment, the Cr content is from 0.01 to 0.25% by weight. In one embodiment, the Cr content is at least 0.02%, or is at least 0.03%, or is at least 0.04%, or is at least 0.05%, or is at least 0.06%, or is at least 0.07%, or is at least 0.08%, or is at least 0.09%, or is at least 0.10%, or is at least 0.11%, or is at least 0.12%, or is at least 0.13%, or is at least 0.14%, or is at least 0.15%, or is at least 0.16%, or is at least 0.17%, or is at least 0.18%, or is at least 0.19%, or is at least 0.20%, or is at least 0.21%, or is at least 0.22%, or is at least 0.23%, and / or is at most 0.24%, or is at most 0.23%, or is at most 0.22%, or is at most 0.21%, or is at most 0.20%, or is at most 0.19%, or is at most 0.18%, or is at most 0.17%, or is at most 0.16%, or is at most 0.15%, or is at most 0.14%, or is at most 0.13%, or is at most 0.12%, or is at most 0.11%, or is at most 0.10%, or is at most 0.09%, or is at most 0.08%, or is at most 0.07%, or is at most 0.06%, or is at most 0.05%, or is at most 0.04%, or is at most 0.03%.

[0040] The other elements are unavoidable impurities whose content is typically at most 0.05% by weight, or at most 0.04%, at most 0.03%, at most 0.02%, at most 0.01%.

[0041] The rest is aluminium.

[0042] In one embodiment of the invention, the alloy comprises at least two elements selected from Co, Ni, Ba, La, Ce, Ta, Ru, Os and Zr, the content of the element if it is selected being from 0.003 to 0.15% by weight, the sum of the content of the selected elements being at least equal to 0.08% by weight and at least one of the selected elements having a content of 0.04% to 0.15% by weight and preferably of 0.05 to 0.10%.

[0043] In one embodiment of the invention, the alloy comprises at least three elements selected from Co, Ni, Ba, La, Ce, Ta, Ru, Os, and Zr, the content of the element, if selected, being from 0.003 to 0.15% by weight, the sum of the content of the selected elements being at least 0.14% by weight, and at least one of the selected elements having a content of 0.04 to 0.15% by weight. Preferably, in this embodiment, the selected elements are Co, Ba, Zr or Ni, Ba, Zr, or Co, La, Zr or Co, Ni, Ba.

[0044] The alloys according to the invention have the advantage of having a smaller average size of intermetallic particles and a reduced average distance between intermetallic particles compared to alloys according to the prior art. Intermetallic particles are less detrimental, particularly to forming, when they are small and closely spaced. The alloys according to the invention are therefore advantageous for reducing process times such as homogenization, for improving forming properties such as elongation and formability, and for improving surface properties such as response to anodizing.

[0045] An object of the invention is a heat-treated wrought product comprising an alloy according to the invention. For the purposes of this invention, a heat-treated product is understood to be a product in a state T, meaning a heat-treated alloy product that has been heat-treated to obtain stable states other than F, O, or H. Typically, the heat-treated product is in a state T3, T4, T5, T6, T7, or T8.

[0046] One object of the invention is a rolled product comprising an alloy according to the invention. A rolled product according to the invention typically has a thickness of 0.5 mm to 300 mm and preferably 0.8 mm to 150 mm. Another object of the invention is a spun product comprising an alloy according to the invention. A spun product according to the invention typically has a thickness of 0.5 mm to 30 mm and preferably 0.8 mm to 20 mm. Another object of the invention is a forged product comprising an alloy according to the invention. A forged product according to the invention typically has a local thickness of 0.5 mm at 300 mm and preferably of 0.8 mm at 150 mm.

[0047] A process for obtaining a heat-treated wrought product according to the invention comprises the steps of - Supply of pure or alloyed aluminium in the form of primary metal ingots from electrolysis and / or pre-consumer manufacturing scrap and / or post-consumer waste, said waste having optionally been melted separately and possibly solidified and of additive elements in appropriate form; - Preparation of a charge with the supplied aluminum, melting of this charge and addition of the alloying elements to obtain a bath of liquid metal alloy according to the invention, - Casting, preferably by direct-cooling vertical semi-continuous casting of said liquid metal bath to obtain a blank suitable for hot forging, typically a rolling plate, a forging blank or a billet; - Homogenization of the rough draft at a temperature of at least 500 °C; - Hot and optionally cold forging of the blank by rolling, drawing and / or forging to obtain a forged product; - Dissolving the wrought product thus obtained at a temperature of at least 500 °C and quenching; - Aging at room temperature and / or tempering of the wrought product put into solution and quenched thus obtained to obtain a heat-treated wrought product.

[0048] In a first step, pure or alloyed aluminium is supplied in the form of primary metal ingots obtained from electrolysis and / or pre-consumer manufacturing scrap and / or post-consumer waste, optionally having been melted separately and possibly solidified, and additive elements in appropriate form.

[0049] Pure or alloyed aluminum in the form of primary metal ingots generally has the disadvantage of generating significant CO2 emissions during its manufacture, and therefore its use is being limited. Regarding other sources of metal, a distinction is made 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 the product has been used, typically from the car at the junkyard. The manufacturing stages of aluminum products generate numerous pre-consumer manufacturing scraps at all stages. Examples of post-consumer waste include the ends of cast plates or billets that were dropped before hot forging, the ends of rolled or drawn products that were dropped during the sheet or profile manufacturing process, blank skeletons used for stamping, machining chips, etc. Examples of post-consumer waste include used window frames, salvaged car parts, crushed cars, dismantled aircraft, etc. Post-consumer waste can be supplied in its raw form, in compacted form, or optionally, having been separately melted and possibly solidified. Alloying elements are also supplied in suitable forms. These can be elements in their metallic form or in an alloyed form. For the addition of rare earth elements such as La, Ce, and Nd, it is advantageous to use the semi-schemal form.

[0050] In a subsequent step, a charge is formed with all or part of the supplied aluminum, this charge is melted, and additives are added to obtain a bath of liquid metal having a composition according to the invention. It is possible that some of the supplied aluminum may already be in liquid form.

[0051] The process according to the invention is advantageous because it allows, during the composition of the feed, the use of a high percentage of manufacturing scrap and / or post-consumer waste. Thus, in one embodiment, the feed contains at least 20%, 30%, 40%, 50%, 60%, 70%, or 80% manufacturing scrap. Similarly, in one embodiment, the feed contains at least 20%, 30%, 40%, 50%, 60%, 70%, or 80% post-consumer waste. Finally, in one embodiment, the feed contains at least 20%, 30%, 40%, 50%, 60%, 70%, or 80% manufacturing scrap and post-consumer waste. The charge is then melted and its composition adjusted using additives to obtain a liquid metal bath having a composition according to the invention.

[0052] In a later step, the bath of liquid metal is poured, preferably by direct-cooling vertical semi-continuous pouring, to obtain a blank suitable for hot forging, typically a rolling plate or a billet.

[0053] In a subsequent step, the resulting blank is homogenized to a temperature of at least 500 °C. The homogenization time during which the entire blank reaches a temperature of at least 500 °C is typically at least 2 hours, or at least 3 hours, or at least 4 hours, or at least 5 hours, or at least 6 hours. In certain embodiments, the alloys according to the invention allow the homogenization time to be reduced. Thus, the homogenization time during which the entire blank reaches a temperature of at least 500 °C is reduced. at most 12 hours or at most 11 hours or at most 10 hours or at most 9 hours or at most 8 hours.

[0054] In a subsequent step, the homogenized blank is hot-forged and optionally cold-forged by rolling, drawing, and / or forging to obtain a wrought product. Hot forging is typically started at a temperature of at least 400 °C. In one embodiment, the blank is cooled from the homogenization temperature to the forging start temperature, optionally by forced cooling. In another embodiment, the blank is cooled to ambient temperature after homogenization and then reheated to reach the hot forging start temperature.

[0055] In a subsequent step, the wrought product thus obtained is placed in solution at a temperature of at least 500 °C and quenched. Quenching is typically carried out in water by immersion or spraying; however, air quenching is also possible for certain products, particularly spun products.

[0056] In an optional subsequent step, the wrought product thus put into solution and quenched can be cold wrought and / or stress-relieved.

[0057] In a later step, the wrought product thus obtained is aged at room temperature and / or tempered in solution to obtain a heat-treated wrought product.

[0058] Among the uses of the products according to the invention, we can mention in particular automotive construction (for example body skin and reinforcement, shock absorption system, battery boxes), building construction (for example framework, joinery, decoration...), aeronautical construction (for example fuselage, electrical connections, ...) and industrial construction (for example pylons, vacuum chambers, railway tracks). EXAMPLES

[0059] Example 1

[0060] In this example, aluminum alloy parts were cast and homogenized for 8 hours at 540 °C. A refining agent A13Ti0.15C was added in the proportion of 1 kg / t. The composition of the parts is given in Table 1 below.

[0061] [Table 1] - Composition of alloys in % by weight Alloy Si Fe Cu Mn Mg Ti Cr Co V Ni Ba Zr C1H 0.7 0.25 0.12 0.18 0.4 0.02 0 0 0 0 0 0 C2H 0.7 0.25 0.12 0.18 0.4 0.02 0.05 0 0 0.05 0.05 0.05 C3H 0.7 0.25 0.5 0.18 0.4 0.08 0 0.05 0.05 0 0.05 0.05 C4H 0.7 0.25 0.5 0.18 0.4 0.08 0.05 0.05 0.05 0.05 0 0 C9H 1.1 0.25 0.12 0.4 0.4 0.02 0.05 0.05 0.05 0 0 0.05 C10H 1.1 0.25 0.12 0.4 0.4 0.02 0 0.05 0.05 0.05 0.05 0 C11H 1.1 0.25 0.5 0.4 0.4 0.08 0.05 0 0 0 0.05 0

[0062] The intermetallic particles of the parts were characterized by scanning electron microscopy over areas of 3300 x 3300 pm². Two parameters were characterized by image analysis: the average size of the intermetallic particles and the average distance between intermetallic particles. The characterization method is illustrated in Figures 5, 6, and 7. Backscatter diffraction (BSD) images of the intermetallic particles, such as those in [Fig. 5], are corrected and binarized ([Fig. 6]), and the images undergo at least two successive object closure steps to quantify the sizes of the intermetallic particles and the distances between them ([Fig. 7]). Image analysis closure steps are performed to measure the average size of the intermetallic particles and the average distance between them.

[0063] The results are presented in Table 2 and shown in [Fig. 1], as a percentage relative to the reference sample C1H. It is indeed more relevant to present the results as a percentage, as the absolute values ​​may be affected by experimental parameters.

[0064] [Table 2] - Reference Average Size (%) Average Distance (%) C1H 100% 100% C2H 60% 80% C3H 64% 82% C4H 76% 92% C9H 76% 86% C10H 64% 78% C11H 91% 93%

[0065] Intermetallic particles are less detrimental, particularly to shaping, when they are small and closely spaced. These two parameters are indeed correlated; since the iron content is constant in the test, the total volume of intermetallic particles is essentially constant in the different tests.

[0066] Example 2

[0067] In this example, aluminum alloy parts were cast and homogenized for 8 hours at 540 °C. A refining agent A13Ti0.15C was added in the proportion of 1 kg / t. The composition of the parts is given in Table 3 below.

[0068] [Table 3] - Composition of alloys in % by weight Alloy Si Fe Cu Mn Mg Ti Cr Co V Ni Ba Zr C5H 0.7 0.5 0.12 0.4 0.4 0.08 0 0 0.05 0.05 0 0.05 C6H 0.7 0.5 0.12 0.4 0.4 0.08 0.05 0 0.05 0 0.05 0 C7H 0.7 0.5 0.5 0.4 0.4 0.02 0 0.05 0 0.05 0.05 0 C8H 0.7 0.5 0.5 0.4 0.4 0.02 0.05 0.05 0 0 0 0.05 C13H 1.1 0.5 0.12 0.18 0.4 0.08 0.05 0.05 0 0.05 0 0 C14H 1.1 0.5 0.12 0.18 0.4 0.08 0 0.05 0 0 0.05 0.05 C15H 1.1 0.5 0.5 0.18 0.4 0.02 0.05 0 0.05 0.05 0.05 0.05 C16H 1.1 0.5 0.5 0.18 0.4 0.02 0 0 0.05 0 0 0

[0069] The intermetallic particles of the parts were characterized by scanning electron microscopy over areas of 3300 x 3300 pm2. Two parameters were characterized by image analysis: the average size of the intermetallic particles and the average distance between the intermetallic particles.

[0070] The results are presented in Table 4 and shown in [Fig. 2], as a percentage relative to the C16H reference sample. It is indeed more relevant to present the results as a percentage, as the absolute values ​​may be affected by experimental parameters.

[0071] [Table 4]- Alloy Average Size (%) Average Distance (%) C5H 70% 84% C6H 97% 86% C7H 84% 83% C8H 85% 83% C13H 69% 87% C14H 28% 50% C15H 70% 86% C16H 100% 100%

[0072] Intermetallic particles are less detrimental, particularly to shaping, when they are small and closely spaced. These two parameters are indeed correlated; since the iron content is constant in the test, the total volume of intermetallic particles is essentially constant in the different tests.

[0073] Example 3

[0074] In this example, aluminum alloy parts were cast and homogenized for 8 hours at 540 °C. A refining agent A13Ti0.15C was added in the proportion of 1 kg / t. The composition of the parts is given in Table 5 below.

[0075] [Table 5] - Composition of alloys in % by weight Alloy Si Fe Cu Mn Mg Ti Cr Co V Ni Ba Zr La D12 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 0.02 5 0.02 5 0.02 5 0.02 5 0.02 5 D17 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 0.05 0.05 0 D18 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 0.05 0.05 0 D19 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 0.05 0.05 D4 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 D7 1.1 0.5 0.12 0.18 0.4 0.03 0.03 5 0.05 0.05 0.05 0

[0076] The intermetallic particles of the parts were characterized by scanning electron microscopy over areas of 3300 x 3300 pm2. Two parameters were characterized by image analysis: the average size of the intermetallic particles and the average distance between the intermetallic particles.

[0077] The results are presented in Table 6 and shown in [Fig.3], as a percentage relative to the reference sample D4. It is indeed more relevant to present the results as a percentage, as the absolute values ​​may be affected by experimental parameters.

[0078] [Table 6] - Alloy Average Size (%) Average Distance (%) D12 90% 90% D17 73% 84% D18 76% 87% D19 79% 81% D4 100% 100% D7 68% 84%

[0079] Example 4

[0080] In this example, aluminum alloy parts were cast and homogenized for 8 hours at 540 °C. A refining agent A13Ti0.15C was added in the proportion of 1 kg / t. The composition of the parts is given in Table 7 below.

[0081] [Table 7] - Composition of alloys in % by weight Alloy Si Fe Cu Mn Mg Ti Cr Co V Ni Ba Zr La D10 1.1 0.5 0.12 0.18 0.4 0.08 0.035 0.05 0.050 0.05 D13 1.1 0.5 0.12 0.18 0.4 0.08 0.200 0.05 0.05 D16 1.1 0.5 0.12 0.18 0.4 0.08 0.200 0.05 D5 1.1 0.5 0.12 0.18 0.4 0.08 0.035 D8 1.1 0.5 0.12 0.18 0.4 0.08 0.035 0.05 0.025 0.025

[0082] The intermetallic particles of the parts were characterized by scanning electron microscopy over areas of 3300 x 3300 pm2. Two parameters were characterized by image analysis: the average size of the intermetallic particles and the average distance between the intermetallic particles.

[0083] The results are presented in Table 8 and shown in [Fig.4], as a percentage relative to the reference sample D5. It is indeed more relevant to present the results as a percentage, as the absolute values ​​may be affected by experimental parameters.

[0084] [Table 8] - Alloy Average Size (%) Average Distance (%) D10 73% 84% D13 80% 83% D16 90% 88% D5 100% 100% D8 76% 87%

[0085] Intermetallic particles are less detrimental, particularly to shaping, when they are small and closely spaced. These two parameters are indeed correlated; since the iron content is constant in the test, the total volume of intermetallic particles is essentially constant in the different tests.

[0086] Example 5

[0087] In this example, parts made of 6082 aluminum alloy, into which 1% by weight of iron and, for one of the tests, 0.2% by weight of La had been added, were cast.

[0088] The intermetallic particles of the parts were characterized by optical microscopy. The results are presented in [Fig. 8], with the addition of La, and [Fig. 9], without the addition of La. The intermetallic particles are smaller in the case of the addition of La, and their distribution is refined by 35% compared to the reference without La.

Claims

Demands

1. Aluminium alloy comprising, in % by weight, Mg: 0.2-1.5; Si: 0.3-2.0; Fe: 0.25-1.0; Ti: 0.01-0.15; - at least one element selected from Co, Ba, Ni, La, Ce, Ta, Mo, W, Nb, Re, Pr, Nd, Pm, Sm, Sc, Y, Ru, Os, the content of the element if selected being from 0.003 to 0.20 and preferably from 0.005 to 0.15, Zr: <0.15; Mn: <1.5; V: <0.20; Zn: <1.0; Cr: <0.25; Cu: <1.5; remaining aluminium and unavoidable impurities, wherein the alloy comprises at least three elements selected from Co, Ni, Ba, La, Ce, Ta, Ru, Os and Zr, the content of the element if selected being from 0.003 to 0.15% by weight, the sum of the content of the selected elements being at least equal to 0.14% by weight and at least one of the selected elements having a content of 0.04% to 0.15% by weight.

2. Alloy according to claim 1 comprising, in % by weight, Zr: 0.003 -0.15 and / or Mn: 0.03 - 1.0 and / or V: 0.05 - 0.20 and / or Zn: 0.03 -1.0 and / or Cr: 0.01 - 0.25 and / or Cu: 0.05 - 1.

0.

3. Alloy according to claim 1 or claim 2 wherein the selected elements are Co, Ba, Zr or Ni, Ba, Zr or Co, La, Zr or Co, Ni, Ba.

4. Alloy according to any one of claims 1 to 3 wherein the Fe content is from 0.35 to 0.85% by weight and preferably between 0.4 and 0.7% by weight.

5. Heat-treated wrought product comprising an alloy according to any one of claims 1 to 4.

6. A method for manufacturing a product according to claim 5 comprising the steps of - Supply of pure or alloyed aluminum in the form of primary metal ingots obtained from electrolysis and / or pre-consumer manufacturing scrap and / or post-consumer waste, said waste having optionally been melted separately and possibly solidified, and of alloying elements in an appropriate form; - Preparation of a charge with the supplied aluminum, melting of this charge and addition of the alloying elements to obtain a bath of liquid metal alloy according to the invention; - Casting, preferably by semi-continuous vertical casting with direct cooling, of said bath of liquid metal to obtain a blank suitable for hot forging, typically a rolling plate, a forging blank or a billet; - Homogenization of the blank at a temperature of at least 500 °C; - Hot and optionally cold forging of the blank by rolling, drawing and / or forging to obtain a wrought product;- Dissolving the wrought product thus obtained at a temperature of at least 500 °C and quenching; - Aging at room temperature and / or tempering the dissolved and quenched wrought product thus obtained to obtain a heat-treated wrought product.

7. A method according to claim 6 wherein the load contains at least 30% post-consumer waste.

8. Use of a product according to claim 5 for automotive construction, building construction, aircraft construction or industrial construction

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