Aluminum alloy with increased scrap absorption

Abstract

The invention relates to an aluminum alloy with increased scrap absorption and strength. The invention also relates to a rolled product consisting of an aluminum alloy according to the invention, to a method for producing the rolled product, and to a component made of the rolled product. The aim of the invention is to provide an aluminum alloy which can be produced inexpensively and which additionally has a high degree of strength. This is achieved in that the composition of the aluminum alloy has the following alloy components: Si: 0.15 wt.% to 0.30 wt.%, Fe: 0.20 wt.% to 0.35 wt.%, Cu: 0.02 wt.% to 0.10 wt.%, Mn: 0.35 wt.% to 0.45 wt.%, Mg: 3.00 wt.% to 3.60 wt.%, Cr: 0.02 wt.% to 0.10 wt.%, Zn: max. 0.20 wt.%, Ti: max. 0.05 wt.%, residual Al and unavoidable impurities, individually: 0.05 wt.%, and in total: max. 0.15 wt.%.

Description

[0001] Aluminum alloy with increased scrap absorption capacity and strength

[0002] The invention relates to an aluminum alloy with increased scrap absorption capacity and strength. The invention also relates to a rolled product consisting of an aluminum alloy according to the invention, a method for producing the rolled product, and a component made from the rolled product.

[0003] A rolled product refers to rolled strips or sheets. Aluminum alloys of type AA5xxx (AlMg) are used in the form of sheets, plates, or strips for the construction of welded or joined structures in shipbuilding, automotive, and aircraft construction. They are characterized in particular by their high strength, which increases with increasing magnesium content. Therefore, aluminum magnesium alloys of type AA5xxx can increasingly replace steel materials in automotive construction, for example, and can thus contribute to further weight reduction in vehicles.

[0004] A standard material of type AA5xxx for automotive interior applications is the aluminum alloy AA5182 (AlMg4.5MnO.4), which in the O / Hlll temper according to DIN EN 485-2 has a yield strength R Po.2 of more than 110 MPa. Due to its high magnesium content, the AA5182 alloy achieves high strengths with good ductility. At the same time, however, it is also cost-intensive to produce due to its high magnesium content and also has only limited absorption capacity for non-pure aluminum scrap. Common materials of the type AA5754 (AlMg3), on the other hand, do not achieve the required strengths due to their lower magnesium content and are also less ductile. Based on this, the object of the present invention is to provide an aluminum alloy which is cost-effective to produce and also has high strength. Furthermore, an advantageous rolled product and a method for producing a rolled product are to be specified, with which rolled products with high strength can be produced cost-effectively.Finally, advantageous components of a motor vehicle, such as body components or body attachments, are to be proposed.

[0005] The above-mentioned object is achieved by an aluminum alloy according to the invention with a composition which has the following alloy components:

[0006] Si: 0.15 wt% to 0.30 wt%,

[0007] Fe: 0.20 wt% to 0.35 wt%,

[0008] Cu: 0.02 wt% to 0.10 wt%,

[0009] Mn: 0.35 wt% to 0.45 wt%,

[0010] Mg: 3.00 wt% to 3.60 wt%,

[0011] Cr: 0.02 wt% to 0.10 wt%,

[0012] Zn: max. 0.20 wt.%,

[0013] Ti: max. 0.05 wt.%,

[0014] Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%.

[0015] It has been found that the aluminum alloy according to the invention can be used to cost-effectively produce aluminum alloy products, particularly rolled products, that are characterized by high strength and good ductility. The specified content limits for the individual alloying elements enable a high scrap absorption capacity, while the closely coordinated contents of Mg, Cu, Mn, and Cr ensure a sufficient level of strength. The aluminum alloy thus allows for a favorable compromise between scrap absorption capacity, strength, and formability of correspondingly manufactured aluminum alloy products.

[0016] In particular, it has been shown that good strength can be achieved with a Mg content of 3.00 wt.% to 3.60 wt.%. The lower limits of 0.02 wt.% for Cu, 0.35 wt.% for Mn, and 0.02 wt.% for Cr allow a further increase in strength. It has been found that with the aid of the alloy composition according to the invention, an AA5754 material is obtained which achieves increased strength compared to known AA5754 standard materials. In particular, the alloy composition according to the invention can achieve the increased strength level of an AA5182 material in the O / Hlll temper.

[0017] At the same time, the aluminum alloy achieves an increased absorption potential for non-segregated aluminum alloy scrap without limiting ductility compared to an AA5754 standard material. Increased absorption potential for non-segregated aluminum alloy scrap particularly includes greater flexibility with regard to available scrap on the scrap market. This includes, for example, non-segregated pre- and post-consumer scrap. It has been shown that the contents of the elements Si and Fe are particularly relevant for the scrap absorption capacity of the aluminum alloy. It was recognized that at contents below 0.15 wt.% Si and below 0.25 wt.% Fe, there is hardly any absorption potential for scrap, and corresponding alloy contents are therefore impractical. A higher Mg content positively influences not only strength but also formability.It was also found that an upper limit for the Zn content of 0.20 wt.% has a positive effect on the tolerance towards the intake of non-pure scrap.

[0018] The silicon (Si) content of the aluminum alloy ranges from 0.15 wt.% to 0.30 wt.%. The lower limit of 0.15 wt.% has proven advantageous with regard to the absorption capacity of the aluminum alloy of non-pure aluminum alloy scrap. At the same time, limiting the Si content to a maximum of 0.30 wt.% leads to improved ductility of the rolled products made from the aluminum alloy and to higher strength, since at a lower Si content, less strength-enhancing Mg is bound in Mg2Si phases. According to an advantageous embodiment of the aluminum alloy, the Si content is from 0.20 wt.% to 0.30 wt.%. The Si content of the aluminum alloy is particularly preferably from 0.25 wt.% to 0.30 wt.%. It was found that a Si content in these areas is associated with a higher scrap absorption capacity, since non-pure scrap can have a quite high Si content.

[0019] The iron (Fe) content of the aluminum alloy ranges from 0.20 wt.% to 0.35 wt.%. It has been found that excessively low Fe contents of less than 0.20 wt.% severely restrict the aluminum alloy's tolerance for ferrous scrap, as common scrap grades generally contain a significant iron content. Therefore, an excessive limitation of the Fe content can hinder the realization of high recyclate contents. At the same time, limiting the Fe content to a maximum of 0.35 wt.% leads to improved formability of the rolled products made from the aluminum alloy. According to an advantageous embodiment of the aluminum alloy, the Fe content is between 0.25 wt.% and 0.35 wt.%. Fe. An Fe content in the range of 0.25 wt.% to 0.35 wt.% has a further positive effect on the absorption capacity of non-uniform scrap. The Fe content is particularly preferably 0.30 wt% to 0.35 wt%.

[0020] The copper (Cu) content of the aluminum alloy ranges from 0.02 wt.% to 0.10 wt.%. By permitting a Cu content of up to 0.10 wt.%, the aluminum alloy achieves increased tolerance, particularly for copper-containing aluminum alloy scrap, which favors the realization of high recycled material contents in the manufacture of rolled products. At the same time, Cu with a minimum content of 0.02 wt.%, along with Mg, Mn, and Cr, has a positive effect on the strength of the aluminum alloy. According to an advantageous embodiment of the aluminum alloy, the Cu content is 0.05 wt.% to 0.10 wt.%, particularly preferably 0.05 wt.% to 0.08 wt.%. It has been shown that Cu thereby contributes to a further increase in strength while maintaining the same ductility.

[0021] The manganese (Mn) content of the aluminum alloy ranges from 0.35 wt.% to 0.45 wt.%. As already explained above, the lower limit of the Mn content of 0.35 wt.%, in combination with the lower limits of Cu and Cr, leads to an increase in the strength of the aluminum alloy compared to a standard AA5754 material. At the same time, a lower limit of 0.35 wt.%, preferably 0.40 wt.%, results in advantageous scrap absorption capacity. Significant strength increases are also achieved with Mn contents of at least 0.40 wt.%.

[0022] The magnesium (Mg) content of the aluminum alloy ranges from 3.00 wt.% to 3.60 wt.%. With a magnesium content of up to 3.60 wt.%, particularly good strength of the aluminum alloy can be achieved. According to an advantageous design of the aluminum alloy, the Mg content is between 3.00 wt.% and 3.30 wt.%. This allows for a particularly advantageous compromise between high strength, good forming behavior, good resistance to intergranular corrosion, and cost-effective production.

[0023] The chromium (Cr) content of the aluminum alloy ranges from 0.02 wt.% to 0.10 wt.%. According to an advantageous embodiment of the aluminum alloy, the Cr content is 0.05 wt.% to 0.10 wt.%. With a lower limit of 0.02 wt.%, preferably 0.05 wt.%, Cr contributes to increasing the strength of the aluminum alloy and simultaneously allows for increased scrap absorption capacity. Limiting the Cr content to a maximum of 0.10 wt.% also improves the forming properties of the aluminum alloy.

[0024] The zinc (Zn) content of the aluminum alloy is max. 0.20 wt.%. A Zn-

[0025] A content of up to 0.20 wt.% is advantageous for the aluminum alloy's increased scrap absorption capacity, especially since Zn removal can be costly. The lower limit for Zn, for example, is at least 0.001 wt.%. According to an advantageous embodiment of the aluminum alloy, the Zn content is max. 0.10 wt.%.

[0026] The maximum titanium (Ti) content of the aluminum alloy is 0.05 wt.%. Ti can be optionally included in the aluminum alloy, e.g., for grain refinement purposes. The aluminum alloy preferably has a Ti content of at least 0.001 wt.%. The maximum content is limited to 0.05 wt.% Ti, as Ti would otherwise have a negative effect on the ductility of the aluminum alloy.

[0027] In addition to the alloying constituents mentioned above, the aluminum alloy contains the remainder of aluminum and unavoidable impurities. Unavoidable impurities are alloying constituents that are not intentionally added to the alloy, but are inevitably present in the aluminum alloy due to the manufacturing process. According to the invention, the content of a single unavoidable impurity is limited to 0.05 wt.%, and the total content of all unavoidable impurities is limited to 0.15 wt.%. This ensures that the unavoidable impurities have no, or no significant, negative effects on the properties of the aluminum alloy, for example, through undesirable phase formation.

[0028] According to a further advantageous embodiment of the aluminum alloy, the sum of the Cu content and the Cr content is > 0.10 wt.%, and / or the Cu content and the Cr content are each > 0.05 wt.% if the Mg content is < 3.30 wt.%. While a corresponding limitation of the Mg content can provide improved corrosion behavior and a more cost-effective aluminum alloy, corresponding minimum contents of Cu and Cr simultaneously ensure high strength of rolled products made from the aluminum alloy. For example, the Mg content is < 3.30 wt.%, whereby the sum of the Cu content and the Cr content is > 0.10 wt.% and / or the Cu content and the Cr content are each > 0.05 wt.%.

[0029] According to a further advantageous embodiment of the aluminum alloy, the sum of the Cu content and the Cr content is < 0.10 wt.%, and / or the Cu content and the Cr content are each < 0.05 wt.% if the Mg content is > 3.30 wt.%. While the strength and formability are positively influenced by more Mg, appropriate upper limits on the Cu and Cr contents ensure that the material does not become too strong and that the ductility remains sufficiently high. For example, the Mg content is > 3.30 wt.%, whereby the sum of the Cu content and the Cr content is < 0.10 wt.% and / or the Cu content and the Cr content are each < 0.05 wt.%.

[0030] According to a further advantageous embodiment of the aluminum alloy, the aluminum alloy achieves a total score of at least 16 points in an assessment of scrap absorption capacity, with the total score being the sum of the individual scores for the Si, Fe, Cu, Mn, Cr, Zn and Ti contents of the aluminum alloy as follows:

[0031] Si content: < 0.15 wt% results in 0 points,

[0032] 0.15 wt% to < 0.25 wt% results in 3 points,

[0033] > 0.25 wt% results in 6 points,

[0034] Fe content: < 0.25 wt% results in 0 points,

[0035] 0.25 wt% to < 0.30 wt% results in 3 points,

[0036] > 0.30 wt% results in 6 points,

[0037] Cu content: < 0.03 wt.% results in 0 points,

[0038] 0.03 wt% to < 0.05 wt% results in 1 point,

[0039] > 0.05 wt% results in 2 points,

[0040] Mn content: < 0.25 wt% results in 0 points,

[0041] 0.25 wt% to < 0.35 wt% results in 1 point,

[0042] > 0.35 wt% results in 2 points,

[0043] Cr content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point,

[0044] > 0.05 wt% results in 2 points, Zn content: < 0.03 wt% results in 0 points,

[0045] 0.03 wt% to < 0.05 wt% results in 1 point,

[0046] > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points,

[0047] 0.03 wt% to < 0.05 wt% results in 1 point,

[0048] > 0.05 wt% results in 2 points.

[0049] The scrap absorption capacity of an aluminum alloy refers specifically to the alloy's tolerance to the absorption of non-uniform scrap. Aluminum alloys with a high scrap absorption capacity allow for particularly high recyclate contents during the production of rolled products from the aluminum alloy. It has been recognized that aluminum alloys that achieve a total score of at least 16 points in the scrap absorption capacity assessment allow for particularly high scrap absorption capacity. Preferably, the aluminum alloy achieves a total score of at least 18 points in the scrap absorption capacity assessment.

[0050] For each individual alloying element, it was possible to determine the ranges in which the respective alloying elements have a different influence on the scrap absorption capacity of an aluminum alloy. For example, it was found that contents of the respective alloying elements below a certain minimum level have a negative impact on the scrap absorption capacity of an aluminum alloy containing these elements. Therefore, contents of the respective alloying elements below a defined minimum value are rated with 0 points.

[0051] In particular, it was found that the Si and Fe contents were lower than the

[0052] The contents of the other aluminum alloying elements have a comparatively high influence on the scrap acceptance capacity of an aluminum alloy of type AA5754. This is primarily due to the fact that aluminum alloy scrap typically has high Si and Fe contents. Aluminum alloys with high Si and / or Fe contents are accordingly more tolerant of the use of scrap. When assessing scrap acceptance capacity, the Si and Fe contents are therefore each given a higher weighting than the contents of the other alloying elements Cu, Mn, Cr, Zn, and Ti. In particular, the Si and Fe contents are weighted three times higher than the contents of the alloying elements Cu, Mn, Cr, Zn, and Ti.

[0053] In particular, aluminum alloys with a total score of less than 10 points in the scrap absorption capacity assessment exhibit low scrap absorption capacity. Aluminum alloys with a total score of 10 or more points in the scrap absorption capacity assessment are more tolerant of scrap absorption. Thus, aluminum alloys with a total score of 10 to 15 points exhibit moderate scrap absorption capacity. Aluminum alloys with a total score of 16 points or more in the scrap absorption capacity assessment exhibit high scrap absorption capacity.

[0054] Aluminum alloys with a total score of 18 points or more in the scrap absorption capacity assessment have a particularly high scrap absorption capacity.

[0055] The above-mentioned object is also achieved by a rolled product according to the invention comprising an aluminum alloy according to the invention. It has been found that, despite the deviations in the chemical composition of the rolled product made from an aluminum alloy with the above-mentioned contents of alloying constituents, a combination of mechanical properties of the rolled product can be achieved which meets the high requirements for processing the rolled product of the aluminum alloy AA5182 and the rolled product can be processed on production facilities designed for this purpose. Rolled products with a low carbon footprint can thus be sustainably manufactured on existing production facilities. In particular, it has been shown that the rolled product according to the invention in the O / Hlll state has the increased yield strength R Po.2 of more than 110 MPa of a rolled product made of an AA5182 alloy according to DIN EN 485-2. Due to the combination of the lower limits of the Mg, Cu, Mn, and Cr contents, higher strengths can be achieved compared to conventional AA5754 products. At the same time, the rolled product exhibits increased tolerance to non-pure aluminum alloy scrap and allows for high recycled content during production.

[0056] According to an advantageous embodiment of the rolled product, the rolled product in the O / Hlll state has a yield strength R P o,2 of 110 MPa or > 110 MPa, for example 110 MPa to 150 MPa, and a tensile strength R m of > 220 MPa, preferably > 230 MPa, measured transverse to the rolling direction. The rolled product thus far exceeds the strength properties required by DIN EN 485-2 for an aluminum alloy of type AA5754.

[0057] According to a further advantageous embodiment of the rolled product, the rolled product in the O / Hlll state has a uniform elongation A g of 18% or > 18% and an elongation at break Asomm of 20% or > 20%. Thus, the rolled product also exceeds the elongation values ​​required for an aluminum alloy of type AA5754 according to DIN EN 485-2.

[0058] The rolled product preferably has a vertical anisotropy no of > 0.55 and / or a hardening exponent ns of > 0.26. The vertical anisotropy no is the vertical anisotropy r measured in the tensile test perpendicular to the rolling direction of the rolled product according to DIN EN ISO 10113:2021-06 at 10% elongation. The hardening exponent ns is the hardening exponent n determined according to DIN EN ISO 10275:2020-12 at 5% elongation. According to a further advantageous embodiment of the rolled product, the rolled product has a thickness of 0.5 mm to 5 mm, preferably 0.7 mm to 3.5 mm, particularly preferably 0.80 mm to 3 mm. The rolled product is therefore excellently suited for most applications, for example in automotive engineering.

[0059] According to a further advantageous embodiment of the rolled product, the rolled product comprises a recycled content of at least 60%, preferably at least 80%. Due to the above-described high scrap absorption capacity of the aluminum alloy, the realization of these high recycled content levels for the rolled product according to the invention is possible without, for example, negatively impacting the process parameters for preferred manufacturing processes.

[0060] The above-mentioned object is also achieved by a method for producing a rolled product, the method comprising the following method steps: Providing a melt of an aluminum alloy with a composition having the following alloying constituents: Si: 0.15 wt.% to 0.30 wt.%,

[0061] Fe: 0.20 wt% to 0.35 wt%,

[0062] Cu: 0.02 wt% to 0.10 wt%,

[0063] Mn: 0.35 wt% to 0.45 wt%,

[0064] Mg: 3.00 wt% to 3.60 wt%,

[0065] Cr: 0.02 wt% to 0.10 wt%,

[0066] Zn: max. 0.20 wt.%,

[0067] Ti: max. 0.05 wt.%,

[0068] Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%,

[0069] Pouring the melt into a rolling ingot, homogenising the rolling ingot at 480 °C to 550 °C for at least 0.5 h,

[0070] Hot rolling of the rolling ingot at a temperature of 280 °C to 520 °C, cold rolling of the rolled product to final thickness with a rolling degree of at least 40%,

[0071] Soft annealing of the finished rolled product at 300 °C to 550 °C.

[0072] The process is used in particular for producing a rolled product according to the invention. The melt is produced in particular from an aluminum alloy according to the invention. It has been shown that the process can be used to produce aluminum alloy products with advantageous strength and forming properties as well as increased flexibility in scrap acceptance. In particular, it has been shown that the process according to the invention can be used to produce a rolled product with an increased yield strength compared to a rolled product made from an AA5182 alloy in the O / Hlll temper. At the same time, the process allows the use of high recycled material contents during production.

[0073] The melt is preferably provided at least partly by melting aluminum scrap, for example at least partly by melting UBC scrap or other pre- and post-consumer scrap.

[0074] The melt is preferably cast into a rolling ingot using a semi-continuous casting process, particularly DC (direct chill) casting. The ingot can then be sawn or milled.

[0075] The rolling ingot is homogenized at a temperature of 480 °C to 550 °C, preferably 520 °C to 550 °C, for example 540 °C, for at least 0.5 h.

[0076] The hot rolling of the rolling ingot takes place at a temperature of 280°C to 520°C. The hot rolling can comprise rough rolling, in particular reversing rolling using a reversing rolling stand, and finish rolling, in particular using a tandem rolling mill. The rough rolling takes place, for example, at a rough rolling temperature of 450°C to 520°C and / or down to an intermediate thickness of 30 mm to 40 mm. The finish rolling can, for example, be carried out down to a final hot strip thickness of 2 mm to 8 mm, preferably 2.8 mm to 7.5 mm. The final hot strip temperature is, for example, 280°C to 350°C, preferably 290°C to 350°C. It is also conceivable for the hot rolling to take place exclusively using a reversing rolling stand. The final thickness of the hot strip with exclusive reversing rolling can be up to 12 mm, for example 8 mm to 12 mm.

[0077] Cold rolling of the aluminum alloy strip to final thickness takes place with a reduction ratio of at least 40%. The final hot strip thickness can, for example, be selected such that after hot rolling, only one cold rolling step follows, in which the hot strip is reduced in thickness to the final thickness with a reduction ratio of at least 40%, for example 40% to 60%, preferably 50% to 60%. It is also conceivable for cold rolling to comprise two or more, for example three or four, cold rolling passes. The reduction ratio during cold rolling can be selected depending on the final hot strip thickness and the desired final thickness after cold rolling. The reduction ratio can, for example, be more than 60%, e.g., 60% to 75%. The final thickness of the cold-rolled strip is, for example, in the range from 0.5 mm to 5 mm, preferably in the range from 0.7 mm to 3.5 mm, more preferably in the range from 0.8 mm to 3.0 mm, particularly preferably 1.0 mm to 2.5 mm.In the final cold rolling pass, an EDT topography can also be imprinted on at least one surface of the rolled product. A surface structure produced by electrical discharge texturing (EDT) allows for a high number of lubricant pockets in the surface profile. This allows the rolled product to have improved formability.

[0078] The finish-rolled aluminum alloy strip is soft-annealed at temperatures between 300 and 550 °C. The finish-rolled aluminum alloy strip can be soft-annealed, for example, at temperatures between 300 and 400 °C in a batch furnace. The holding time during soft-annealing is, for example, 0.5 to 4 hours. The holding time is the duration for which the aluminum alloy strip is held at the final temperature. After soft-annealing, the aluminum alloy strip can be cooled. Cooling takes place either in the batch furnace or after the coil is removed from the batch furnace. The surface of the rolled product can then be chemically pretreated and oiled.

[0079] According to an advantageous embodiment of the method for producing a rolled product, soft annealing is carried out in a continuous furnace. It has been shown that soft annealing in a continuous furnace can significantly increase the ductility of the rolled product compared to coil annealing carried out in a batch furnace. In particular, continuous strip annealing can achieve advantageous isotropy of the grain structure of the rolled product. The soft annealing of the finish-rolled aluminum alloy strip in a continuous furnace takes place at 380 °C to 550 °C, preferably 400 °C to 550 °C, with a holding time of, for example, 0 s to 60 s, preferably 0 s to 30 s. After soft annealing, the aluminum alloy strip can be cooled. The cooling takes place, for example, using air or water or a combination of both.

[0080] According to an advantageous embodiment of the process for producing a rolled product, the melt comprises a recycled material content of at least 60%. Preferably, the melt comprises a recycled material content of at least 80%. Due to the high recycling tolerance of the aluminum alloy described above, the use of this high recycled material content in the process for producing rolled products is possible. The associated energy savings enable the manufacture of rolled products with the lowest possible carbon footprint and achieve improved sustainability. The recycled material used preferably has a post-consumer scrap content of at least 30%, preferably at least 50%, particularly preferably at least 70%. Since post-consumer scrap only arises at the end of the product life cycle, it is considered particularly sustainable and contributes more significantly to reducing the carbon footprint.Cumulatively or alternatively, the recycled material used contains at least 30%, preferably at least 50%, particularly preferably at least 70% or at least 75%, of pre-consumer scrap, internal and / or external process scrap. In the case of internal process scrap, the compositions and quantities of the individual alloys are generally very well known, so that the alloy composition resulting from the melting of internal process scrap can be easily determined. External process scrap is less well-defined in its composition than internal process scrap and may require further processing steps. However, it is generated on a large scale, for example, in the production of stamped parts, making recycling highly relevant both economically and in terms of sustainability. Recycling external process scrap can reduce the need for primary metal, which lowers the overall carbon dioxide (CO2) balance.With the aluminum alloy composition, recycled material contents of at least 90% can preferably be achieved.

[0081] The above-mentioned object is also achieved by a component for a motor vehicle consisting at least partially of a rolled product according to the invention. As already explained above, the rolled product has excellent properties with regard to strength, forming properties and scrap absorption capacity during production. A component consisting at least partially of a rolled product according to the invention is particularly advantageous if it is designed as a body or body attachment part of a motor vehicle. Typical body parts are the fender or parts of the floor assembly, the roof, etc. Body attachment parts are components that are not permanently connected to the motor vehicle, for example doors and tailgates, etc. Invisible body components or body attachments are preferably produced from the rolled product according to the invention.These include, for example, interior door parts, interior hood parts, interior trunk lid parts, or interior tailgate parts, etc. Interior body parts are often subject to complex forming processes in order to produce the interior body parts from as few individual components as possible. This eliminates additional work steps related to joining technology, such as joining or welding different components. At the same time, interior body parts are also exposed to corrosive conditions, so good corrosion resistance is also required. The rolled product meets these conditions to a particularly high degree, making it ideal for this application. It is also conceivable that the component is designed as part of a chassis, particularly a running gear, for a motor vehicle.

[0082] Furthermore, the present invention relates to an aluminum alloy, in particular of type AA5754, wherein the aluminum alloy achieves a total score of at least 16 points in an evaluation of scrap absorption capacity, wherein the total score is calculated from the sum of the individual scores for the contents of Si, Fe, Cu, Mn, Cr, Zn and Ti of the aluminum alloy as follows:

[0083] Si content: < 0.15 wt% results in 0 points,

[0084] 0.15 wt% to < 0.25 wt% results in 3 points,

[0085] > 0.25 wt% results in 6 points,

[0086] Fe content: < 0.25 wt% results in 0 points,

[0087] 0.25 wt% to < 0.30 wt% results in 3 points,

[0088] > 0.30 wt% results in 6 points,

[0089] Cu content: < 0.03 wt.% results in 0 points,

[0090] 0.03 wt% to < 0.05 wt% results in 1 point,

[0091] > 0.05 wt% results in 2 points,

[0092] Mn content: < 0.25 wt% results in 0 points,

[0093] 0.25 wt% to < 0.35 wt% results in 1 point,

[0094] > 0.35 wt% results in 2 points,

[0095] Cr content: < 0.03 wt% results in 0 points,

[0096] 0.03 wt% to < 0.05 wt% results in 1 point,

[0097] > 0.05 wt% results in 2 points,

[0098] Zn content: < 0.03 wt% results in 0 points,

[0099] 0.03 wt% to < 0.05 wt% results in 1 point,

[0100] > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points,

[0101] 0.03 wt% to < 0.05 wt% results in 1 point,

[0102] > 0.05 wt% results in 2 points.

[0103] The invention will now be explained in more detail using exemplary embodiments in conjunction with the drawing. The drawing shows in

[0104] Fig. 1 is a schematic flow diagram for an embodiment of a method according to the invention for producing a rolled product, and

[0105] Fig. 2 is a schematic representation of an embodiment of a component according to the invention for a motor vehicle.

[0106] Fig. 1 schematically shows the process steps and the sequence of one exemplary embodiment of a method for producing a rolled product. The method comprises, in step A, providing a melt of an aluminum alloy. The melt has a recycled content of at least 80%. The aluminum alloy has the following composition:

[0107] Si: 0.15 wt% to 0.30 wt%,

[0108] Fe: 0.20 wt% to 0.35 wt%,

[0109] Cu: 0.02 wt% to 0.10 wt%,

[0110] Mn: 0.35 wt% to 0.45 wt%,

[0111] Mg: 3.00 wt% to 3.60 wt%,

[0112] Cr: 0.02 wt% to 0.10 wt%,

[0113] Zn: max. 0.20 wt.%,

[0114] Ti: max. 0.05 wt.%,

[0115] The remainder is Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%. Preferably, the aluminum alloy can also have the following composition:

[0116] Si: 0.20 wt% to 0.30 wt%,

[0117] Fe: 0.25 wt% to 0.35 wt%,

[0118] Cu: 0.05 wt% to 0.08 wt%,

[0119] Mn: 0.35 wt% to 0.45 wt%,

[0120] Mg: 3.00 wt% to 3.30 wt%,

[0121] Cr: 0.05 wt% to 0.10 wt%,

[0122] Zn: max. 0.10 wt.%,

[0123] Ti: max. 0.05 wt.%,

[0124] Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%.

[0125] In step B, the process involves casting the molten aluminum alloy into a rolling ingot. This is typically done using the DC casting process.

[0126] In step C, the resulting rolling ingot is optionally homogenized for at least 0.5 hours at a temperature of 480 °C to 550 °C, preferably at 500 °C to 550 °C. The homogenization can be integrated into a preheating process of the rolling ingot prior to hot rolling or can be carried out separately.

[0127] In process step D, the rolling ingot is then hot-rolled. The final hot-rolled strip temperature is between 280°C and 520°C. The final thickness of the hot-rolled strip is, for example, 2 to 10 mm, preferably 3 to 8 mm. The final hot-rolled strip thickness can be selected so that after hot rolling, only one cold-rolling step E follows, in which the hot-rolled strip is reduced in thickness to the final thickness with a reduction ratio of at least 40%, for example 40% to 60%, preferably 50% to 60%. The aluminum alloy strip, cold-rolled to its final thickness, is then subjected to soft annealing. Soft annealing is preferably carried out at a temperature of 380°C to 550°C in a continuous furnace for a maximum of 300 s.

[0128] Examples of the rolled product according to the invention and rolled products as comparative examples were now manufactured from different aluminum alloys in the O / Hlll temper. It was assumed that the rolled products, upon reaching the specified mechanical parameters for the yield strength R P o,2 > 110 MPa, tensile strength Rm > 230 MPa, uniform elongation A g > 18% and elongation at break Asomm > 20%, the advantageous yield strength level of an aluminum alloy type AA5182 is achieved with typical tensile strengths and elongations of the aluminum alloy type AA5754 in the O / Hlll temper. At the same time, the rolled products were evaluated for their scrap absorption capacity.

[0129] Table 1 shows the alloy compositions of the working examples (Exp.J) and the comparative examples (Comp.J). Each individual example was manufactured using the process parameters given in Fig. 1.

[0130] Finally, Table 2 shows the achieved mechanical properties and the scrap absorption capacity of the examples. All mechanical parameters such as yield strength R P o,2, tensile strength Rm, uniform elongation A g and elongation at break Asomm were determined according to EN ISO 6892-1:2019. The hardening exponent ns was determined according to DIN EN ISO 10275:2020-12 as the hardening exponent n at 5% elongation.

[0131] To evaluate the scrap absorption capacity, the respective total scores were calculated for the alloys, which result from the respective sums of the respective individual scores for the contents of Si, Fe, Cu, Mn, Cr, Zn and Ti of the aluminum alloy as follows:

[0132] Si content: < 0.15 wt% results in 0 points,

[0133] 0.15 wt% to < 0.25 wt% results in 3 points, > 0.25 wt% results in 6 points, Fe content: < 0.25 wt% results in 0 points,

[0134] 0.25 wt% to < 0.30 wt% results in 3 points,

[0135] > 0.30 wt% results in 6 points,

[0136] Cu content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point,

[0137] > 0.05 wt% results in 2 points,

[0138] Mn content: < 0.25 wt% results in 0 points, 0.25 wt% to < 0.35 wt% results in 1 point,

[0139] > 0.35 wt% results in 2 points, Cr content: < 0.03 wt% results in 0 points,

[0140] 0.03 wt% to < 0.05 wt% results in 1 point,

[0141] > 0.05 wt% results in 2 points,

[0142] Zn content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point,

[0143] > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points,

[0144] 0.03 wt% to < 0.05 wt% results in 1 point,

[0145] > 0.05 wt% results in 2 points.

[0146] Aluminum alloys with a total score of less than 10 points in the scrap absorption capacity assessment demonstrate low scrap absorption capacity. Aluminum alloys with a total score of 10 to 15 points demonstrate moderate scrap absorption capacity. Aluminum alloys with a total score of more than 16 points in the scrap absorption capacity assessment, on the other hand, demonstrate high scrap absorption capacity.

[0147] Examples 13, 14, and 15 are rolled products according to the teachings of the invention. These comprise aluminum alloys that allow high recycled material contents and thus have a high scrap absorption capacity. At the same time, the yield strengths R P o,2 > 110 MPa, tensile strengths Rm > 230 MPa, uniform elongation A g > 18% and elongations at break Asomm > 20%.

[0148] Comparative Examples 2, 3, 4, 5, 6, 7, 8, and 9 exhibit only moderate scrap absorption capacities. While Comparative Examples 3 and 8 exhibit comparatively low Fe contents of <0.30 wt.%, and Comparative Example 3 also exhibits a low Cu content of <0.05 wt.%, a Mn content of <0.35 wt.%, and a Cr content of 0.03 wt.%, Comparative Examples 5, 6, 7, 8, and 9 exhibit particularly low Si contents of <0.25 wt.%.

[0149] Comparative examples 1, 10, 11 and 12, on the other hand, exhibit particularly low scrap absorption capacities. This is mainly due to the low Fe contents of

[0150] < 0.25 wt.%. In addition, these alloy compositions have low Cr contents of < 0.03 wt.%, while Comparative Examples 10, 11, and 12 simultaneously have low Si and Cu contents of < 0.15 wt.% and 0.03 wt.%, respectively.

[0151] In addition, comparative examples 1, 2, 3 and 4 do not meet the requirements for the strength of the rolled products, but have yield strengths R P o,2 < 110 MPa and tensile strengths Rm < 230 MPa, which are below the minimum values ​​for an aluminum alloy of type AA5182 or AA5754 in the O / Hlll temper.

[0152] Table 1

[0153] *All values ​​in wt.%, remainder aluminum and unavoidable impurities, individually max. 0.05 wt.%, in total 0.15 wt.%

[0154] Table 2

[0155] Table 3 also provides exemplary cold rolling pass sequences for cold rolling E. Cold rolling E can comprise two or more, for example, three or four, cold rolling passes. The degree of reduction during cold rolling E can be selected depending on the final hot strip thickness and the desired final thickness after cold rolling.

[0156] Table 3

[0157] Finally, Fig. 2 schematically shows a component for a motor vehicle. The component consists at least partially of a rolled product manufactured according to the process shown in Fig. 1. Sheets were cut from the aluminum alloy strip produced using the process according to Fig. 1, and from these sheets, an interior part of a motor vehicle body in the form of an inner door part was produced by forming, for example, drawing. These are usually made of steel. However, the rolled products according to the invention are preferably used for the production of interior body parts due to their high strength and high formability.

[0158] The disclosure also includes the following embodiments:

[0159] 1. Aluminium alloy with a composition comprising the following alloying constituents: Si: 0.15 wt% to 0.30 wt%,

[0160] Fe: 0.20 wt% to 0.35 wt%,

[0161] Cu: 0.02 wt% to 0.10 wt%,

[0162] Mn: 0.35 wt% to 0.45 wt%,

[0163] Mg: 3.00 wt% to 3.60 wt%,

[0164] Or: 0.02 wt% to 0.10 wt%,

[0165] Zn: max. 0.20 wt.%,

[0166] Ti: max. 0.05 wt.%,

[0167] The remainder is Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%. An aluminum alloy according to embodiment 1, wherein the alloying constituents Si, Fe, Cu, Mg, Cr, and / or Zn have the following contents:

[0168] Si: 0.20 wt% to 0.30 wt%,

[0169] Fe: 0.25 wt% to 0.35 wt%,

[0170] Cu: 0.05 wt% to 0.10 wt%, preferably 0.05 wt% to

[0171] 0.08 wt.%,

[0172] Mg: 3.00 wt% to 3.30 wt%,

[0173] Cr: 0.05 wt% to 0.10 wt%,

[0174] Zn: max. 0.10 wt.%. Aluminum alloy according to embodiment 1 or 2, wherein the sum of Cu content and Cr content is > 0.10 wt.% when the Mg content is < 3.30 wt.%. Aluminum alloy according to one of embodiments 1 to 3, wherein the Cu content and the Cr content are each > 0.05 wt.% when the Mg content is < 3.30 wt.%. 5. Aluminum alloy according to one of embodiments 1 to 4, wherein the sum of Cu content and Cr content is < 0.10 wt.% when the Mg content is > 3.30 wt.%.

[0175] 6. Aluminum alloy according to one of embodiments 1 to 5, wherein the Cu content and the Cr content are each < 0.05 wt.% when the Mg content is > 3.30 wt.%.

[0176] 7. The aluminum alloy according to any one of embodiments 1 to 6, wherein the aluminum alloy achieves a total score of at least 16 points in an evaluation of scrap absorption capacity, wherein the total score is the sum of the scores for the contents of Si, Fe, Cu, Mn, Cr, Zn and / or Ti of the aluminum alloy as follows:

[0177] Si content: < 0.15 wt% results in 0 points,

[0178] 0.15 wt% to < 0.25 wt% results in 3 points,

[0179] > 0.25 wt% results in 6 points, Fe content: < 0.25 wt% results in 0 points,

[0180] 0.25 wt% to < 0.30 wt% results in 3 points,

[0181] > 0.30 wt% results in 6 points, Cu content: < 0.03 wt% results in 0 points,

[0182] 0.03 wt% to < 0.05 wt% results in 1 point,

[0183] > 0.05 wt% results in 2 points, Mn content: < 0.25 wt% results in 0 points,

[0184] 0.25 wt% to < 0.35 wt% results in 1 point,

[0185] > 0.35 wt% results in 2 points, Cr content: < 0.03 wt% results in 0 points,

[0186] 0.03 wt% to < 0.05 wt% results in 1 point,

[0187] > 0.05 wt% results in 2 points, Zn content: < 0.03 wt% results in 0 points,

[0188] 0.03 wt% to < 0.05 wt% results in 1 point,

[0189] > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points,

[0190] 0.03 wt% to < 0.05 wt% results in 1 point,

[0191] > 0.05 wt% results in 2 points.

[0192] 8. Rolled product comprising an aluminum alloy according to any one of embodiments 1 to 7.

[0193] 9. Rolled product according to embodiment 8, wherein the rolled product in the O / Hlll state has a yield strength Rpo,2 of > 110 MPa and a tensile strength R m of > 230 MPa measured transverse to the rolling direction.

[0194] 10. Rolled product according to embodiment 8 or 9, wherein the rolled product in the O / Hlll state has a uniform elongation A g of > 18% and an elongation at break Asomm of > 20%.

[0195] 11. Rolled product according to any one of embodiments 8 to 10, wherein the rolled product has a thickness of 0.5 mm to 5 mm.

[0196] 12. Rolled product according to one of embodiments 8 to 11, wherein the rolled product comprises a recycled content of at least 60%, preferably at least 80%.

[0197] 13. A method for producing a rolled product, in particular a rolled product according to one of embodiments 8 to 12, the method comprising the following method steps:

[0198] Providing a melt of an aluminum alloy having a composition comprising the following alloying components:

[0199] Si: 0.15 wt% to 0.30 wt%,

[0200] Fe: 0.20 wt% to 0.35 wt%,

[0201] Cu: 0.02 wt% to 0.10 wt%,

[0202] Mn: 0.35 wt% to 0.45 wt%, Mg: 3.00 wt% to 3.60 wt%,

[0203] Or: 0.02 wt% to 0.10 wt%,

[0204] Zn: max. 0.20 wt.%,

[0205] Ti: max. 0.05 wt.%,

[0206] Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%,

[0207] Pouring the melt into a rolling ingot,

[0208] Homogenization of the rolling ingot at 480 °C to 550 °C for at least 0.5 h,

[0209] Hot rolling of the rolling ingot at a temperature of 280 °C to 520 °C, cold rolling of the rolled product to final thickness with a rolling degree of at least 40%,

[0210] Soft annealing of the finished rolled product at 300 °C to 550 °C.

[0211] 14. The method according to embodiment 13, wherein the soft annealing is carried out in a continuous furnace.

[0212] 15. The process according to embodiment 13 or 14, wherein the melt comprises a recycled material content of at least 60%, preferably at least 80%.

[0213] 16. Component for a motor vehicle at least partially consisting of a rolled product according to one of embodiments 8 to 12 and / or produced by a method according to one of embodiments 13 to 15.

Claims

Patent claims 1. Aluminium alloy with a composition which Alloy components: Si: 0.15 wt% to 0.30 wt%, Fe: 0.20 wt% to 0.35 wt%, Cu: 0.02 wt% to 0.10 wt%, Mn: 0.35 wt% to 0.45 wt%, Mg: 3.00 wt% to 3.60 wt%, Cr: 0.02 wt% to 0.10 wt%, Zn: max. 0.20 wt.%, Ti: max. 0.05 wt.%, Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in Total max. 0.15 wt.%, characterized in that the aluminum alloy achieves a total score of at least 16 points in an assessment of scrap absorption capacity, whereby the total score is calculated from the sum of the scores for the Si, Fe, Cu, Mn, Cr, Zn and / or Ti contents of the aluminum alloy as follows: Si content: < 0.15 wt% results in 0 points, 0.15 wt% to < 0.25 wt% results in 3 points, > 0.25 wt% results in 6 points, Fe content: < 0.25 wt% results in 0 points, 0.25 wt% to < 0.30 wt% results in 3 points, > 0.30 wt% results in 6 points, Cu content: < 0.03 wt.% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Mn content: < 0.25 wt% results in 0 points, 0.25 wt% to < 0.35 wt% results in 1 point, > 0.35 wt% results in 2 points, Cr content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Zn content: < 0.03 wt.% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points.

2. Aluminium alloy according to claim 1, characterized in that the alloying constituents Si, Fe, Cu, Mg, Cr and / or Zn have the following contents: Si: 0.20 wt% to 0.30 wt%, Fe: 0.25 wt% to 0.35 wt%, Cu: 0.05 wt% to 0.10 wt%, preferably 0.05 wt% to 0.08 wt%, Mg: 3.00 wt% to 3.30 wt%, Cr: 0.05 wt% to 0.10 wt%, Zn: max. 0.10 wt%.

3. Aluminium alloy according to claim 1 or 2, characterized in that the sum of Cu content and Cr content is > 0.10 wt.% when the Mg content is < 3.30 wt.%.

4. Aluminium alloy according to one of claims 1 to 3, characterized in that the Cu content and the Cr content are each > 0.05 wt% if the Mg content is < 3.30 wt%.

5. Aluminum alloy according to one of claims 1 to 4, characterized in that the sum of Cu content and Cr content is < 0.10 wt.% when the Mg content is > 3.30 wt.%.

6. Aluminum alloy according to one of claims 1 to 5, characterized in that the Cu content and the Cr content are each < 0.05 wt.% when the Mg content is > 3.30 wt.%.

7. A rolled product comprising an aluminum alloy according to any one of claims 1 to 6.

8. Rolled product according to claim 7, characterized in that the rolled product in the O / Hlll state has a yield strength Rpo,2 of > 110 MPa and a tensile strength R m of > 230 MPa measured transverse to the rolling direction.

9. Rolled product according to claim 7 or 8, characterized in that the rolled product in the O / Hlll state has a uniform elongation A g of > 18% and an elongation at break Asomm of > 20%.

10. Rolled product according to one of claims 7 to 9, characterized in that the rolled product has a thickness of 0.5 mm to 5 mm.

11. Rolled product according to one of claims 7 to 10, characterized in that the rolled product comprises a recycled content of at least 60%, preferably at least 80%.

12. A method for producing a rolled product, in particular a rolled product according to one of claims 7 to 11, the method comprising the following method steps: Providing a melt of an aluminum alloy having a composition comprising the following alloying constituents: Si: 0.15 wt% to 0.30 wt%, Fe: 0.20 wt% to 0.35 wt%, Cu: 0.02 wt% to 0.10 wt%, Mn: 0.35 wt% to 0.45 wt%, Mg: 3.00 wt% to 3.60 wt%, Cr: 0.02 wt% to 0.10 wt%, Zn: max. 0.20 wt.%, Ti: max. 0.05 wt.%, Remainder Al and unavoidable impurities, individually max. 0.05 wt.%, in total max. 0.15 wt.%, whereby the aluminum alloy achieves a total score of at least 16 points in an assessment of scrap absorption capacity, whereby the total score is calculated from the sum of the scores for the contents of Si, Fe, Cu, Mn, Cr, Zn and / or Ti of the aluminum alloy as follows: Si content: < 0.15 wt% results in 0 points, 0.15 wt% to < 0.25 wt% results in 3 points, > 0.25 wt% results in 6 points, Fe content: < 0.25 wt% results in 0 points, 0.25 wt% to < 0.30 wt% results in 3 points, > 0.30 wt% results in 6 points, Cu content: < 0.03 wt.% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Mn content: < 0.25 wt% results in 0 points, 0.25 wt% to < 0.35 wt% results in 1 point, > 0.35 wt% results in 2 points, Cr content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Zn content: < 0.03 wt.% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Ti content: < 0.03 wt% results in 0 points, 0.03 wt% to < 0.05 wt% results in 1 point, > 0.05 wt% results in 2 points, Pouring the melt into a rolling ingot, Homogenization of the rolling ingot at 480 °C to 550 °C for at least 0.5 h, hot rolling of the rolling ingot at a temperature of 280 °C to 520 °C, cold rolling of the rolled product to final thickness with a rolling degree of at least 40%, Soft annealing of the finished rolled product at 300 °C to 550 °C.

13. A method according to claim 12, characterized in that the soft annealing is carried out in a continuous furnace.

14. The method according to claim 12 or 13, characterized in that the melt comprises a recycled material content of at least 60%, preferably at least 80%.

15. Component for a motor vehicle at least partially consisting of a rolled product according to one of claims 7 to 11 and / or produced by a method according to one of claims 12 to 14.

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