EP3662092A1 - Panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx - Google Patents

Panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx

Info

Publication number
EP3662092A1
EP3662092A1 EP18753328.6A EP18753328A EP3662092A1 EP 3662092 A1 EP3662092 A1 EP 3662092A1 EP 18753328 A EP18753328 A EP 18753328A EP 3662092 A1 EP3662092 A1 EP 3662092A1
Authority
EP
European Patent Office
Prior art keywords
aluminium alloy
sheet product
outer panel
alloy sheet
automotive outer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP18753328.6A
Other languages
German (de)
English (en)
Inventor
Philippe Meyer
Els Verboom
Aleksandar Lozanov DAVIDKOV
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aleris Aluminum Duffell BVBA
Original Assignee
Aleris Aluminum Duffell BVBA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aleris Aluminum Duffell BVBA filed Critical Aleris Aluminum Duffell BVBA
Publication of EP3662092A1 publication Critical patent/EP3662092A1/fr
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/05—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
    • C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon

Definitions

  • Automotive outer panel made from a 6xxx-series aluminium alloy sheet product
  • the invention relates to an automotive outer panel made from a 6xxx-series aluminium alloy sheet product and to a method of manufacturing such a panel.
  • outer body panels of a vehicle require excellent physical properties in formability, dent-resistance, corrosion resistance and surface quality.
  • the conventional AA5xxx-series alloy sheets have not been favoured because they have low mechanical strength even after press forming and may also exhibit poor surface quality. Therefore, 6xxx-series sheet alloys have been increasingly used.
  • the 6xxx-series alloys provide excellent bake hardenability after painting and high mechanical strength as a result, thus making it possible to manufacture more thin-gauged and more lightweight sheets in combination with a good corrosion resistance and class-A surface finish.
  • aluminium alloy designations and temper designations refer to the Aluminium Association designations in Aluminium Standards and Data and the Registration Records, as pub- lished by the Aluminium Association in 2016 and well known to the persons skilled in the art.
  • the temper designations are laid down in European standard EN515.
  • up to 0.15% Zn may include an alloy having no Zn.
  • an automotive outer panel made from a 6xxx-series aluminium alloy sheet product consisting of, in wt.%: Si 0.54% to 0.75%, Mg 0.57% to 0.80%, Cu 0.03% to 0.20%, Mn 0.06% to 0.20%, Fe 0.10% to 0.25%, wherein the ratio of Fe to Mn is in a range of 1 .0 to 2.30 (Fe:Mn), Cr up to 0.09%, Zn up to 0.15%, V up to 0.04%, Ti up to 0.15%, other elements and unavoidable impurities each up to 0.05%, total up to 0.2%, balance aluminium.
  • the automotive outer panel made of the defined aluminium alloy sheet product by carefully controlling the compositional ranges of the aluminium alloy (with preferred ranges herein set forth and claimed) and its manufacturing route provides a good balance of low strength and good formability, in particular also a good hemming performance, in a T4P temper (relates to material in a T4 temper and that has undergone a pre-ageing treatment), and a high paint bake response and high strength in a T64 temper (after 2% prestrain and a simulated paint bake cycle of 185°C/20 min). While maintaining this balance, it has been found that the aluminium sheet product has a very good re- sistance to corrosion.
  • IGC intergranular corrosion
  • the aluminium alloy sheet product applied has in a T4P temper a tensile strength (R m or UTS) of 180 MPa or more, preferably at least 195 MPa, a yield point (Rpo.2 or YS) of 1 15 MPa or less when measured within 3-10 days after solution heat treatment and quench, but the yield point (R p o.2 or YS) is less than 130 MPa after 6 months storage at ambient (room) temperature, an elongation at break (Asomm) of at least 24%, an uniform elongation (A g ) of at least 20%, a strain hardening exponent (n5%) of at least 0.26.
  • the aluminium alloy sheet product has in a T64 temper a tensile strength (R m ) of 260 MPa or more, a yield point (Rpo.2) of 195 MPa or more, and an elongation at break (Asomm) of at least 14%.
  • the aluminium alloy sheet product contains at least 0.58% Si, and more preferably at least 0.60%. At Si levels below 0.54%, the yield strength is reduced to a level making the sheet product less suitable for vehicle outer panels.
  • a preferred upper-limit for the Si-content is 0.75%, more preferably 0.70%, and most preferably 0.68%.
  • the Mg-content in the aluminium alloy sheet product is preferably at most 0.74%, and more preferably of 0.70%, and most preferably at most 0.65%.
  • the ratio of wt.% Si to wt.% Mg is less than 1 .20
  • the ratio of Si to Mg is at least 0.90 (Si:Mg). In an embodiment, the ratio of Si to Mg is at least 0.95 (Si:Mg). This narrow range of Si:Mg ratio is to improve the formability in the T4P temper and to increase the strength in the T64 temper of the aluminium alloy sheet product.
  • Copper (Cu) is present in the aluminium alloy sheet product for at least 0.03% and can be present up to 0.20%.
  • a preferred upper-limit for the Cu-content is 0.1 1 %, a preferred upper-limit is 0.08%, and more preferably 0.07%.
  • the manga- nese (Mn)-content is at least 0.10%.
  • a preferred upper-limit for the Mn-content is 0.18%, and more preferably 0.15%.
  • a preferred lower-limit for the Fe-content is 0.12%, and preferably 0.15%.
  • the ratio of wt.% Fe to wt.% Mn is less than 2.0, more preferably less than 1 .8 (Fe:Mn).
  • a lower- limit for the Fe to Mn ratio is 1 .0, and preferably 1 .15.
  • Chromium (Cr) can be present in the aluminium alloy sheet product in a range of up to 0.09%.
  • a more preferred upper-limit for the Cr-content is 0.07%, and more preferably 0.04%.
  • a preferred lower limit for the Cr-content is 0.01 %.
  • Zinc (Zn) is an impurity element that can be tolerated up to about 0.15%, and is preferably as low as possible, e.g. 0.06% or less.
  • Zirconium (Zr) is preferentially avoided in the aluminium alloy, and an upper- limit for Zr is 0.02%, preferably 0.01 %, and more preferably 0.008%.
  • Vanadium (V) can be present in the aluminium alloy sheet product up to about 0.04%.
  • the aluminium alloy includes not greater than 0.03% V, and more preferably not greater than 0.02% V, as it may have an adverse effect on the r-value of the aluminium sheet in the T4P temper.
  • Titanium (Ti) can be added to the aluminium alloy sheet product amongst others for grain refiner purposes during casting of the aluminium alloy rolling ingots.
  • the addition of Ti should not exceed about 0.15%, and preferably it should not ex- ceed 0.10%.
  • a preferred lower limit for the Ti addition is 0.01 %, and typically a preferred upper-limit for Ti is 0.05%, and can be added as a sole element or with either boron or carbon serving as a casting aid, for grain size control.
  • Unavoidable impurities can be present each up to 0.05% and the total is up to 0.15%, the balance is made with aluminium.
  • the resistance to intergranular corrosion (IGC) after 1 ,000 hours at 150°C has been tested in accordance with European standard ISO-1 1846, April 2008, section 6.2.2 Method B.
  • the aluminium sheet product according to this invention has typically a corrosion depth of less than 200 ⁇ .
  • a preferred thickness of the aluminium alloy sheet product when used as an automotive outer panel is in the range of 0.7 mm to 4.0 mm, and preferably in a range of 0.7 mm to 2.0 mm, for example, a thickness of about 1 .0 mm or about 1 .3 mm.
  • the aluminium alloy sheet product is formed by a monolithic rolled product and is devoid of any cladding (for example, applied by means of roll bonding or casting technology) made of another aluminium alloy, for example, a dilute Al-Mg alloy or another 6xxx-series alloy or a 3xxx-series alloy.
  • cladding for example, applied by means of roll bonding or casting technology
  • another aluminium alloy for example, a dilute Al-Mg alloy or another 6xxx-series alloy or a 3xxx-series alloy.
  • the 6xxx-series aluminium alloy sheet product used in accordance with this invention has been manufactured via a method comprising the steps of casting (e.g. direct chill (DC) casting) an ingot of the 6xxx aluminium alloy of defined composition, homogenizing the ingot at a temperature in a range for 520°C to 570°C for at least 5 hours, hot rolling, cold rolling to intermediate gauge, to improve the surface quality of the final sheet product an intermediate annealing (e.g. batch annealing at a temperature of about 345°C to 410°C), cold rolling to a final gauge in a range of 0.7 mm to 4.0 mm (e.g.
  • DC direct chill
  • solution heat treating the rolled sheet product wherein the solution heat treating comprises heating the rolled sheet product to a temperature in the range of 530°C to 570°C and for a time such that substantially all of Mg2Si, and excess Si, if any, in the rolled sheet product are dissolved into solid solution, and after the solution heat treating, quenching the rolled product.
  • the sheet product is subjected to pre-ageing treatment and then natural aged to provide a T4P temper; the natural ageing occurs as a result of storing at ambient (room) temperature, typically for about 72 hours up to 6 months, until forming into an automotive body member, in particular into a three-dimensional automotive outer panel.
  • ambient (room) temperature typically for about 72 hours up to 6 months
  • the pre-age treatment temperature is a key processing parameter to arrive at the desired balance of mechanical and physical properties in the T4P and T64 temper.
  • a pre-age temperature of about 60°C-75°C does not provide the required level of paint bake response, which is only achieved after pre- ageing at a temperature in a range of 90°C-105°C.
  • the desired pre-age heat treatment comprises of heating the aluminium alloy sheet product to a temperature in a range of 90°C to 105°C followed by immediate coiling the sheet material (coiling temperature is the pre-age temperature) and cooling of the coiled sheet material in an ambient environment to ambient temperature and storing of the cooled coiled material.
  • the three-dimensional formed part is made part of an assembly of other metal com- ponents as is regular in the art for manufacturing vehicle components, and subjected to a paint bake operation to cure any paint or lacquer layer applied.
  • the paint bake operation or cycle comprises one or more sequential short heat treatment in the range of 140°C to 210°C for a period of 10 to less than 40 minutes.
  • a typical paint bake cycle would comprise a first heat treatment of 185°C@20 minutes, cooling to ambient temperature, then 160°C@20 minutes and cooling to ambient temperature.
  • such a paint bake cycle may comprise of 2 to 5 sequential steps and includes drying steps.
  • sheet products are commonly subjected to a so-called simulated paint bake cycle 2% prestrain followed by a heat treatment of 1 85°C@20 minutes only; this would bring the product to a T64 temper.
  • the difference in strength between T64 and T4P is often referred to as the paint-bake response.
  • it relates to the use of an aluminium alloy sheet product as herein described and claimed for an automotive outer panel formed from said aluminium alloy sheet product in T4P temper.
  • the invention also relates to an automotive vehicle door comprising an outer panel made from such an aluminium alloy sheet product.
  • the IGC corrosion resistance has been tested in accordance with ISO1 1846 on T4P samples after 1000 hours at 150°C. The deepest penetration in microns is measured, and the mean of three measurements is given here.
  • the aluminium alloys have been DC-cast into rolling ingots, then homogenised and hot rolled to a gauge of 8mm.
  • The are first cold rolled to an intermediate gauge of 3mm and batch annealed at about 380°C, then are cold rolled to a final gauge of 1 .0 mm. They are then subsequently subject to a continuous solution heat treatment at about 550°C and pre-aging at about 100°C and immediately coiled at this temperature and cooled to room temperature in an ambient environment.
  • Alloys no. 1 and 2 are according to the invention, and Alloy no. 3 is a comparative alloy.
  • alloys no. 1 , 2, and 3 The deepest IGC penetration for alloys no. 1 , 2, and 3 was respectively 63 micron, 86 micron, and 76 micron. Table 1. Alloy compositions, the Cr, V and Zn are at impurity level, balance is made by other impurities and aluminium.
  • the alloy according to the invention meets the requirements that in a T4P temper it has a tensile strength of 180 MPa or more, preferably at least 195 MPa, a yield point of 1 15 MPa or less when measured within 3-10 days after solution heat treatment and quench, and an elon- gation at break of at least 24%, an uniform elongation of at least 20%, a strain hardening exponent (n-value) of at least 0.26.
  • the yield point was less than 130 MPa after 6 months storage at room temperature.
  • the sheet product has an IGC corrosion resistance well below the required threshold of less than 200 micron.
  • the aluminium alloy sheet product has in a T64 temper a tensile strength of 260 MPa or more, a yield point of 195 MPa or more, and an elongation at break of at least 14%.
  • DC-cast ingots of an aluminium alloy according to this invention has been processed in accordance with the invention into 1 .0mm sheet material except for a difference in the pre-age temperature.
  • the composition of the aluminium alloy is listed in Table 2.
  • One alloy has been pre-aged at about 100°C (4A) and one at about 70°C (4B) and immediately coiled at this tem- perature and cooled to room temperature in an ambient environment.
  • An aluminium alloy having a composition (see Table 5) outside the current invention has been processed on an industrial scale to 1 .0 mm sheet material and similar as in Example 1 is tested for its yield strength, ultimate tensile strength, elon- gation at break, uniform elongation Ag, and the n- and r-value (mean over three measurements) and the corrosion resistance in the T4P condition and for its mechanical properties in the T64 condition.
  • the results are listed in Table 6.
  • the deepest IGC penetration in T4P after 1000 hours at 150°C was 239 micron. Table 5. Alloy composition, the Cr, V and Zn are at impurity level, balance is made by other impurities and aluminium.
  • the aluminium alloy meets the requirements that in a T4P temper it has a tensile strength of 180 MPa, a yield point of 1 15 MPa or less when measured within 3-10 days after solution heat treatment and quench, and an elongation at break of at least 24%, an uniform elongation of at least 20%, together with a strain hardening exponent (n-value) of at least 0.26.
  • n-value strain hardening exponent

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)

Abstract

L'invention concerne un panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx dont la composition, en pourcentage en poids, est la suivante : Si 0,54 % à 0,75 %; Mg 0,57 % à 0,80 %; Cu 0,03 % à 0,20 %; Mn 0,06 % à 0,20 %; Fe 0,10 % à 0,25 %, le rapport du Fe au Mn se situant dans la plage de 1,0 à 2,30 (Fe:Mn); Cr jusqu'à 0,09 %; Zn jusqu'à 0,15 %; V jusqu'à 0,04 %; Ti jusqu'à 0,15 %; autres éléments et impuretés inévitables, chacun jusqu'à 0,05 %; total jusqu'à 0,2 %; le reste étant de l'aluminium.
EP18753328.6A 2017-08-02 2018-07-30 Panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx Pending EP3662092A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP17184490 2017-08-02
PCT/EP2018/070532 WO2019025335A1 (fr) 2017-08-02 2018-07-30 Panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx

Publications (1)

Publication Number Publication Date
EP3662092A1 true EP3662092A1 (fr) 2020-06-10

Family

ID=59520809

Family Applications (1)

Application Number Title Priority Date Filing Date
EP18753328.6A Pending EP3662092A1 (fr) 2017-08-02 2018-07-30 Panneau extérieur d'automobile constitué d'un produit en feuille d'alliage d'aluminium de série 6xxx

Country Status (3)

Country Link
US (1) US20210025046A1 (fr)
EP (1) EP3662092A1 (fr)
WO (1) WO2019025335A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210087656A1 (en) * 2019-09-25 2021-03-25 Apple Inc. Cosmetic aluminum alloys made from recycled aluminum scrap
CN114941091A (zh) * 2022-04-29 2022-08-26 天津忠旺铝业有限公司 一种车身外板用6000系铝合金板材及其制备方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050000609A1 (en) * 2002-12-23 2005-01-06 Butler John F. Crash resistant aluminum alloy sheet products and method of making same
EP1812232B1 (fr) 2004-11-16 2019-06-19 Aleris Aluminum Duffel BVBA Materiau en feuille d'aluminium composite
WO2007129391A1 (fr) 2006-05-01 2007-11-15 Ibiden Co., Ltd. Unité de montage de gabarit de cuisson, unité de démontage de gabarit de cuisson, appareil de circulation, procédé de moulage de céramique de cuisson, et processus de production de structure de nid d'abeille
EP1852251A1 (fr) 2006-05-02 2007-11-07 Aleris Aluminum Duffel BVBA Matériel de tole d'aluminium composite
EP2156945A1 (fr) 2008-08-13 2010-02-24 Novelis Inc. Produit de tôle plaquée automobile
EP2110235A1 (fr) * 2008-10-22 2009-10-21 Aleris Aluminum Duffel BVBA Produit de feuille en rouleau d'alliage Al-Mg-Si doté d'un ourlet convenable
JP6506678B2 (ja) * 2015-11-02 2019-04-24 株式会社神戸製鋼所 自動車構造部材用アルミニウム合金板およびその製造方法

Also Published As

Publication number Publication date
US20210025046A1 (en) 2021-01-28
WO2019025335A1 (fr) 2019-02-07

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