JP5918209B2 - Aluminum alloy sheet for forming - Google Patents

Aluminum alloy sheet for forming Download PDF

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JP5918209B2
JP5918209B2 JP2013267591A JP2013267591A JP5918209B2 JP 5918209 B2 JP5918209 B2 JP 5918209B2 JP 2013267591 A JP2013267591 A JP 2013267591A JP 2013267591 A JP2013267591 A JP 2013267591A JP 5918209 B2 JP5918209 B2 JP 5918209B2
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aluminum alloy
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plate
solid solution
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JP2015124396A (en
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有賀 康博
康博 有賀
久郎 宍戸
久郎 宍戸
松本 克史
克史 松本
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Kobe Steel Ltd
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/043Changing 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 with silicon as the next major constituent
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/02Alloys based on aluminium with silicon as the next major constituent
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/06Alloys based on aluminium with magnesium as the next major constituent
    • C22C21/08Alloys based on aluminium with magnesium as the next major constituent with silicon
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/05Changing 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

Description

本発明は成形用Al−Mg−Si系アルミニウム合金板に関するものである。本発明で言うアルミニウム合金板とは、熱間圧延板や冷間圧延板などの圧延板であって、溶体化処理および焼入れ処理などの調質が施された後であって、焼付け塗装硬化処理される前のアルミニウム合金板を言う。また、以下の記載ではアルミニウムをアルミやAlとも言う。   The present invention relates to an Al—Mg—Si aluminum alloy sheet for forming. The aluminum alloy sheet referred to in the present invention is a rolled sheet such as a hot-rolled sheet or a cold-rolled sheet, and is subjected to tempering such as solution treatment and quenching process, and is baked and coated and cured. Says aluminum alloy plate before being done. In the following description, aluminum is also referred to as aluminum or Al.

近年、地球環境などへの配慮から、自動車等の車両の軽量化の社会的要求はますます高まってきている。かかる要求に答えるべく、自動車パネル、特にフード、ドア、ルーフなどの大型ボディパネル(アウタパネル、インナパネル)の材料として、鋼板等の鉄鋼材料にかえて、成形性や焼付け塗装硬化性に優れた、より軽量なアルミニウム合金材の適用が増加しつつある。   In recent years, due to consideration for the global environment and the like, social demands for weight reduction of vehicles such as automobiles are increasing. In order to meet such demands, as a material for large-sized body panels (outer panels, inner panels) such as automobile panels, especially hoods, doors, roofs, etc., instead of steel materials such as steel plates, it was excellent in formability and bake coating curability. The application of lighter aluminum alloy materials is increasing.

この内、自動車のフード、フェンダー、ドア、ルーフ、トランクリッドなどのパネル構造体の、アウタパネル (外板) やインナパネル( 内板) 等のパネルには、薄肉でかつ高強度アルミニウム合金板として、Al−Mg−Si系のAA乃至JIS 6000系 (以下、単に6000系とも言う) アルミニウム合金板の使用が検討されている。   Among these, panels such as outer panels (outer plates) and inner panels (inner plates) of panel structures such as automobile hoods, fenders, doors, roofs, and trunk lids are thin and high-strength aluminum alloy plates. Al-Mg-Si-based AA to JIS 6000-series (hereinafter also simply referred to as 6000-series) aluminum alloy plates have been studied.

この6000系アルミニウム合金板は、Si、Mgを必須として含み、特に過剰Si型の6000系アルミニウム合金は、これらSi/Mgが質量比で1以上である組成を有し、優れた時効硬化能を有している。このため、プレス成形や曲げ加工時には低耐力化により成形性を確保するとともに、成形後のパネルの塗装焼付処理などの、比較的低温の人工時効( 硬化) 処理時の加熱により時効硬化して耐力が向上し、パネルとしての必要な強度を確保できる焼付け塗装硬化性(以下、ベークハード性=BH性、焼付硬化性とも言う) がある。   This 6000 series aluminum alloy plate contains Si and Mg as essential components. Particularly, the excess Si type 6000 series aluminum alloy has a composition in which these Si / Mg is 1 or more in mass ratio, and has excellent age hardening ability. Have. For this reason, formability is ensured by reducing the yield strength during press molding and bending, and age hardening is achieved by heating during relatively low-temperature artificial aging (curing) treatment such as paint baking treatment of panels after molding. And bake coating curability (hereinafter also referred to as bake hard property = BH property, bake curability) that can secure the required strength as a panel.

また、6000系アルミニウム合金板は、Mg量などの合金量が多い他の5000系アルミニウム合金などに比して、合金元素量が比較的少ない。このため、これらアルミニウム合金板のスクラップを、アルミニウム合金溶解材 (溶解原料) として再利用する際に、元の6000系アルミニウム合金鋳塊が得やすく、リサイクル性にも優れている。   Further, the 6000 series aluminum alloy plate has a relatively small amount of alloy elements as compared with other 5000 series aluminum alloys having a large amount of alloy such as Mg. For this reason, when these aluminum alloy sheet scraps are reused as an aluminum alloy melting material (melting raw material), the original 6000 series aluminum alloy ingot is easily obtained, and the recyclability is excellent.

一方、自動車のアウタパネルは、周知の通り、アルミニウム合金板に対し、プレス成形における張出成形時や曲げ成形などの成形加工が複合して行われて製作される。例えば、フードやドアなどの大型のアウタパネルでは、張出などのプレス成形によって、アウタパネルとしての成形品形状となされ、次いで、このアウタパネル周縁部のフラットヘムなどのヘム (ヘミング) 加工によって、インナパネルとの接合が行われ、パネル構造体とされる。   On the other hand, as is well known, an outer panel of an automobile is manufactured by combining an aluminum alloy plate with a forming process such as an extension forming in a press forming or a bending forming. For example, a large outer panel such as a hood or door is formed into a molded product shape as an outer panel by press molding such as overhanging, and then the inner panel and Are joined to form a panel structure.

ここで、6000系アルミニウム合金は、優れたBH性を有するという利点がある反面で、室温時効性を有し、溶体化焼入れ処理後、数ヶ月間の室温保持で時効硬化して強度が増加することにより、パネルへの成形性、特に曲げ加工性が低下する課題があった。例えば、6000系アルミニウム合金板を自動車パネル用途に用いる場合、アルミメーカーで溶体化焼入れ処理された後(製造後)、自動車メーカーでパネルに成形加工されるまでに、通常は1〜4ヶ月間程度室温におかれ(室温放置され)、この間で、かなり時効硬化(室温時効)することとなる。特に、厳しい曲げ加工が入るアウタパネルにおいては、製造後1ヵ月経過後では、問題無く成形可能であっても、3ヶ月経過後では、ヘム加工時に割れが生じるなどの問題が有った。したがって、自動車パネル用、特にアウタパネル用の6000系アルミニウム合金板では、1〜4ヶ月間程度の比較的長期に亙る室温時効を抑制する必要がある。   Here, the 6000 series aluminum alloy has an advantage of having excellent BH property, but has aging property at room temperature, and after the solution quenching treatment, it is age-hardened by holding at room temperature for several months to increase the strength. As a result, there is a problem that the formability to the panel, particularly the bending workability, is lowered. For example, when a 6000 series aluminum alloy plate is used for an automotive panel application, it is usually about 1 to 4 months after being solution-quenched by an aluminum maker (after manufacture) and before being molded into a panel by an automobile maker. It is left at room temperature (and left at room temperature), and during this time, it is considerably age-hardened (room temperature aging). In particular, in the outer panel that undergoes severe bending, there was a problem that cracking occurred at the time of hem processing after three months even though it could be molded without any problem after one month after manufacture. Therefore, it is necessary to suppress room temperature aging over a relatively long period of about 1 to 4 months in a 6000 series aluminum alloy plate for automobile panels, particularly for outer panels.

更に、このような室温時効が大きい場合には、BH性が低下して、成形後のパネルの塗装焼付処理などの、比較的低温の人工時効( 硬化) 処理時の加熱によっては、パネルとしての必要な強度までに、耐力が向上しなくなるという問題も生じる。   Furthermore, when such room temperature aging is large, the BH property decreases, and depending on the heating during relatively low temperature artificial aging (curing) treatment such as paint baking treatment of the panel after molding, There is also a problem that the yield strength is not improved to the required strength.

従来から、6000系アルミニウム合金板の組織、特に含有元素が形成する化合物(晶出物、析出物)の観点から、成形性やBH性の向上、あるいは室温時効の抑制を図るなどの特性向上について、種々の提案がなされている。最近では、特に、6000系アルミニウム合金板のBH性や室温時効性に影響するクラスタ(原子の集合体)を直接測定して制御する試みなども提案されている。   Conventionally, from the viewpoint of the structure of a 6000 series aluminum alloy sheet, particularly the compound (crystallized product, precipitate) formed by the contained elements, improvement of properties such as improvement of formability and BH property, or suppression of room temperature aging Various proposals have been made. Recently, in particular, attempts have been made to directly measure and control clusters (aggregates of atoms) that affect the BH properties and room temperature aging properties of 6000 series aluminum alloy plates.

また、本発明におけるSnの添加に関係する先行特許としても、6000系アルミニウム合金板にSnを積極的に添加し、室温時効を抑制と焼付け塗装硬化を向上させる方法も多数提案されている。例えば、特許文献1では、経時変化抑制効果を有するSnを適量添加し、また溶体化処理後に予備時効を施すことで、室温時効抑制と焼付け塗装硬化を兼備する方法が兼備されている。また、特許文献2では、経時変化抑制効果を有するSnと成形性を向上させるCuを添加して、成形性、焼付け塗装性、耐食性を向上させる方法が提案されている。   In addition, as a prior patent related to the addition of Sn in the present invention, a number of methods have been proposed in which Sn is positively added to a 6000 series aluminum alloy sheet to suppress room temperature aging and improve bake coating hardening. For example, in Patent Document 1, there is a method that combines room temperature aging suppression and baking coating curing by adding an appropriate amount of Sn having a temporal change suppressing effect and applying pre-aging after solution treatment. Patent Document 2 proposes a method for improving formability, baking paintability, and corrosion resistance by adding Sn having a temporal change suppressing effect and Cu for improving formability.

特開平09-249950号公報JP 09-249950 A 特開平10-226894号公報JP-A-10-226894 特開2000−144294号公報JP 2000-144294 A 特開2003−221637号公報JP 2003-221737 A 特開2003−268472号公報JP 2003-268472 A

ただし、従来のSnを積極的に添加したAl−Mg−Si系アルミニウム合金板でも、長時間の室温時効後の良好な成形性と高いBH性とを兼備するのには、未だ改善の余地があった。   However, even Al-Mg-Si based aluminum alloy sheets positively added with conventional Sn still have room for improvement in order to have both good formability after prolonged aging at room temperature and high BH properties. there were.

このような課題に鑑み、本発明の目的は、長時間の室温時効後の車体塗装焼付け処理であっても、高いBH性と良好な加工性とが発揮できる、Snを含む成形用Al−Mg−Si系アルミニウム合金板を提供することである。   In view of such problems, the object of the present invention is to form Sn-containing Al-Mg that can exhibit high BH properties and good workability even in the case of car body paint baking after long-term aging at room temperature. -To provide a Si-based aluminum alloy sheet.

この目的を達成するために、本発明の成形用アルミニウム合金板の要旨は、質量%で、Mg:0.3〜1.3%、Si:0.5〜1.5%、Sn:0.005〜0.2%を各々含み、残部がAlおよび不可避的不純物からなるAl−Mg−Si系アルミニウム合金板であって、この板のSn含有量から、熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を差し引いたSnの量が0.005質量%以上であることとする。   In order to achieve this object, the gist of the forming aluminum alloy sheet of the present invention is, in mass%, Mg: 0.3-1.3%, Si: 0.5-1.5%, Sn: 0.5. An Al—Mg—Si aluminum alloy plate containing 005 to 0.2% each, the balance being Al and unavoidable impurities, separated from the Sn content of this plate by a residue extraction method using hot phenol The amount of Sn obtained by subtracting the Sn content contained in the residual compound having a particle size exceeding 0.1 μm is 0.005% by mass or more.

Snは、Al−Mg−Si系アルミニウム合金板の組織において、室温においては、原子空孔を捕獲(捕捉、トラップ)することで、室温でのMgやSiの拡散を抑制し、室温における強度増加を抑制し、板のパネルへの成形時に、ヘム加工性や絞り加工や張出加工などのプレス成形性(以下、このプレス成形性を代表してヘム加工性とも言う)を向上させる効果がある。そして、パネルの塗装焼き付け処理などの人工時効処理時には捕獲していた空孔を放出するため、逆にMgやSiの拡散を促進し、BH性を高くすることができる。   Sn, in the structure of Al-Mg-Si based aluminum alloy sheet, captures atomic vacancies at room temperature (capture, trap), thereby suppressing the diffusion of Mg and Si at room temperature and increasing the strength at room temperature. Has the effect of improving press formability such as hem workability, drawing and overhanging (hereinafter also referred to as hem workability as a representative of this press formability) when forming plates into panels. . And since the vacancies captured during the artificial aging treatment such as the paint baking treatment of the panel are released, the diffusion of Mg and Si can be promoted and the BH property can be increased.

ただ、本発明者らの知見によれば、このようなSnの添加には、Sn特有の特性からくる大きな制約が存在する。Snの原子空孔の捕獲や放出効果は、Snがマトリックスに固溶して初めて発揮される。しかしながら、Snのマトリックスへの固溶量はごく少なく(低く)、通常の板の製造方法では、Snの添加量を理論固溶量以下に抑えたとしても、その多くが固溶せずに、化合物として晶出あるいは析出してしまう。このように化合物として晶出あるいは析出したSnには原子空孔の捕獲や放出効果が無い。   However, according to the knowledge of the present inventors, such addition of Sn has a great restriction due to the characteristics peculiar to Sn. The effect of capturing and releasing Sn atomic vacancies is exhibited only when Sn is dissolved in the matrix. However, the amount of Sn dissolved in the matrix is very small (low), and in the ordinary plate manufacturing method, even if the addition amount of Sn is kept below the theoretical solid solution amount, most of it does not dissolve, Crystallized or precipitated as a compound. Thus, Sn crystallized or precipitated as a compound has no effect of trapping or releasing atomic vacancies.

このため、本発明では、板の製造方法も敢えて見直した上で、後述する通り、中間焼鈍などの製造条件を工夫し、含有するSnの存在状態を制御して、Snの化合物としての析出を抑制し、Snのマトリックスへの固溶を促進して、Snの固溶量を確保する。これによって、Snの原子空孔の捕獲や放出効果による時効抑制によって、ヘム加工性やBH性の向上効果を十分に発揮させる。   For this reason, in this invention, after deliberately reviewing the manufacturing method of the plate, as described later, the manufacturing conditions such as intermediate annealing are devised, and the presence state of the contained Sn is controlled to precipitate Sn as a compound. It suppresses and promotes the solid solution of Sn in the matrix, and ensures the solid solution amount of Sn. As a result, the effect of improving heme workability and BH property is sufficiently exhibited by the trapping of Sn atomic vacancies and the suppression of aging by the release effect.

これによって、板製造後に例えば100日間の長時間室温時効した場合であっても、より高い成形性やBH性が発揮できる、Sn入りAl−Mg−Si系アルミニウム合金板を提供できる。   Thereby, even if it is a case where it is aged at room temperature for a long time, for example, for 100 days after the production of the plate, it is possible to provide an Sn-containing Al—Mg—Si based aluminum alloy plate that can exhibit higher formability and BH properties.

ちなみに、従来のSn入りAl−Mg−Si系アルミニウム合金板では、このようなSnの効果を充分に発揮できてはいなかった。   Incidentally, the conventional Sn-containing Al—Mg—Si based aluminum alloy plate could not sufficiently exhibit such effects of Sn.

その理由は、従来は、主要元素であるMgやSiの固溶や析出には常に注目しながらも、選択的な添加元素の一つでしかなかった、Snの固溶や析出の存在形態には、あまり注目していなかったためであると推考される。また、常法により製造された板のSnの存在形態は、化合物としての晶出あるいは析出(以下、単に析出とも言う)である。これとは異なり、しかも、Snを固溶させること自体が難しく、Snの固溶状態がごく稀な存在形態であるため、Snの固溶により発揮される効果について、知見しにくかったためであると推考される。   The reason for this is that in the past, the solid solution and precipitation of Sn, which was only one of the selective additive elements, while always paying attention to the solid solution and precipitation of the main elements Mg and Si. This is probably due to the fact that they did not pay much attention. Further, the Sn present form of the plate produced by a conventional method is crystallization or precipitation (hereinafter, also simply referred to as precipitation) as a compound. In contrast to this, it is difficult to solidify Sn itself, and since the solid solution state of Sn is a very rare form, it is difficult to know the effects exhibited by the solid solution of Sn. Inferred.

以下に、本発明の実施の形態につき、要件ごとに具体的に説明する。   Hereinafter, embodiments of the present invention will be specifically described for each requirement.

(化学成分組成)
先ず、本発明のAl−Mg−Si系(以下、6000系とも言う)アルミニウム合金板の化学成分組成について、以下に説明する。本発明が対象とする6000系アルミニウム合金板は、自動車のパネル用の板などとして、優れた成形性やBH性、強度、溶接性、耐食性などの諸特性が要求される。
(Chemical composition)
First, the chemical component composition of the Al—Mg—Si (hereinafter also referred to as 6000) aluminum alloy sheet of the present invention will be described below. The 6000 series aluminum alloy plate targeted by the present invention is required to have excellent properties such as formability, BH property, strength, weldability, and corrosion resistance as a plate for an automobile panel.

このような要求を満足するために、アルミニウム合金板の組成は、質量%で、Mg:0.3〜1.3%、Si:0.5〜1.5%、Sn:0.005〜0.2%を各々含み、残部がAlおよび不可避的不純物からなるものとする。なお、各元素の含有量の%表示は全て質量%の意味である。   In order to satisfy such requirements, the composition of the aluminum alloy plate is, by mass, Mg: 0.3 to 1.3%, Si: 0.5 to 1.5%, Sn: 0.005 to 0. 2% each, and the balance consisting of Al and inevitable impurities. In addition,% display of content of each element means the mass% altogether.

本発明が対象とする6000系アルミニウム合金板は、BH性がより優れた、SiとMgとの質量比Si/ Mgが1 以上であるような過剰Si型の6000系アルミニウム合金板とされるのが好ましい。6000系アルミニウム合金板は、プレス成形や曲げ加工時には低耐力化により成形性を確保するとともに、成形後のパネルの塗装焼付処理などの、比較的低温の人工時効処理時の加熱により時効硬化して耐力が向上し、必要な強度を確保できる優れた時効硬化能(BH性)を有している。この中でも、過剰Si型の6000系アルミニウム合金板は、質量比Si/ Mgが1未満の6000系アルミニウム合金板に比して、このBH性がより優れている。   The 6000 series aluminum alloy plate targeted by the present invention is an excess Si type 6000 series aluminum alloy plate having a better BH property and a Si / Mg mass ratio of Si / Mg of 1 or more. Is preferred. The 6000 series aluminum alloy sheet secures formability by reducing the yield strength during press molding and bending, and is age-hardened by heating during relatively low temperature artificial aging treatment such as paint baking treatment of the panel after molding. Yield strength is improved, and it has excellent age-hardening ability (BH property) that can secure the required strength. Among these, the excess Si type 6000 series aluminum alloy plate is more excellent in this BH property than the 6000 series aluminum alloy plate having a mass ratio Si / Mg of less than 1.

本発明では、これらMg、Si以外のその他の元素は不純物あるいは含まれても良い元素であり、AA乃至JIS規格などに沿った各元素レベルの含有量 (許容量) とする。   In the present invention, these other elements other than Mg and Si are impurities or elements that may be contained, and the content (allowable amount) at each element level is in accordance with AA to JIS standards.

すなわち、資源リサイクルの観点から、本発明でも、合金の溶解原料として、高純度Al地金だけではなく、Mg、Si以外のその他の元素を添加元素(合金元素)として多く含む6000系合金やその他のアルミニウム合金スクラップ材、低純度Al地金などを多量に使用した場合には、下記のような他の元素が必然的に実質量混入される。そして、これらの元素を敢えて低減する精錬自体がコストアップとなり、ある程度の含有を許容することが必要となる。また、これらの元素を実質量含有しても、本発明目的や効果を阻害しない有用な含有範囲がある。   That is, from the viewpoint of resource recycling, in the present invention, not only high-purity Al ingots but also 6000 series alloys containing many other elements other than Mg and Si as additive elements (alloy elements) are used as melting raw materials for alloys. When a large amount of aluminum alloy scrap material, low-purity Al metal, etc. is used, the following other elements are necessarily mixed in substantial amounts. And refining itself that dares to reduce these elements increases the cost, and it is necessary to allow a certain amount of inclusion. Moreover, even if these elements are contained in substantial amounts, there is a useful content range that does not impair the object and effects of the present invention.

したがって、本発明では、このような下記元素を各々以下に規定するAA乃至JIS 規格などに沿った上限量以下の範囲での含有を許容する。   Accordingly, in the present invention, the following elements are allowed to be contained in the range of the upper limit amount or less in accordance with AA to JIS standards defined below.

具体的には、Mn:1.0%以下(但し、0%を含まず)、Cu:1.0%以下(但し、0%を含まず)、Fe:1.0%以下(但し、0%を含まず)、Cr:0.3%以下(但し、0%を含まず)、Zr:0.3%以下(但し、0%を含まず)、V:0.3%以下(但し、0%を含まず)、Ti:0.05%以下(但し、0%を含まず)、Zn:1.0%以下(但し、0%を含まず)、Ag:0.2%以下(但し、0%を含まず)の1種または2種以上を、この範囲で、上記した基本組成に加えて、更に含んでも良い。   Specifically, Mn: 1.0% or less (excluding 0%), Cu: 1.0% or less (excluding 0%), Fe: 1.0% or less (excluding 0%) %), Cr: 0.3% or less (excluding 0%), Zr: 0.3% or less (excluding 0%), V: 0.3% or less (provided that 0% not included), Ti: 0.05% or less (excluding 0%), Zn: 1.0% or less (excluding 0%), Ag: 0.2% or less (excluding In addition to the basic composition described above, one or more of the above may be further contained within this range.

なお、これらの元素を含有する場合、Cuは含有量が多いと耐食性を劣化させやすいので、好ましくはCuの含有量を0.7%以下、より好ましくは0.3%以下とする。また、Mn、Fe、Cr、Zr、Vは、含有量が多いと比較的粗大な化合物を生成しやすく、本発明で課題とするヘム加工性(ヘム曲げ性)を劣化させやすい。このため、Mn含有量は、好ましくは0.6%以下、より好ましくは0.3%以下、Cr、Zr、V含有量は、好ましくは0.2%以下、より好ましくは0.1%以下と各々する。   In addition, when these elements are contained, since Cu tends to deteriorate corrosion resistance when the content is large, the Cu content is preferably 0.7% or less, more preferably 0.3% or less. Further, when Mn, Fe, Cr, Zr, and V are contained in a large amount, a relatively coarse compound is likely to be generated, and the hem workability (hem bendability) that is a subject of the present invention is likely to be deteriorated. Therefore, the Mn content is preferably 0.6% or less, more preferably 0.3% or less, and the Cr, Zr, V content is preferably 0.2% or less, more preferably 0.1% or less. And each.

上記6000系アルミニウム合金における、各元素の含有範囲と意義、あるいは許容量について以下に順に説明する。   The content range and significance of each element in the 6000 series aluminum alloy, or the allowable amount will be described in order below.

Si:0.5〜1.5%
Siは、主要元素として、固溶強化と、塗装焼き付け処理などの人工時効処理時に、強度向上に寄与するMg−Si系析出物を形成して、時効硬化能を発揮し、自動車のアウタパネルとして必要な強度(耐力)を得るための必須の元素である。また、パネルへの成形後の塗装焼き付け処理での優れた時効硬化能を発揮させるためには、Si/ Mgを質量比で1.0以上とし、一般に言われる過剰Si型よりも更にSiをMgに対し過剰に含有させた6000系アルミニウム合金組成とすることが好ましい。Si含有量が少なすぎると、Mg−Si系析出物の生成量が不足するため、BH性が著しく低下する。一方、Si含有量が多すぎると、粗大な晶出物および析出物が形成されて、曲げ加工性が著しく低下する。したがって、Siは0.5〜1.5%の範囲とする。さらに好ましい下限値は0.6%であり、さらに好ましい上限値は1.4%である。
Si: 0.5 to 1.5%
Si is a major element that forms Mg-Si precipitates that contribute to strength improvement during solid solution strengthening and artificial aging treatments such as paint baking treatment, and exhibits age-hardening ability and is required as an outer panel for automobiles It is an indispensable element for obtaining a sufficient strength (yield strength). In addition, in order to exhibit excellent age-hardening ability in the paint baking process after forming on the panel, Si / Mg is set to a mass ratio of 1.0 or more, and Si is further added to Mg rather than the excessive Si type generally referred to. It is preferable to make the composition of 6000 series aluminum alloy excessively contained. If the Si content is too small, the amount of Mg-Si-based precipitates is insufficient, and the BH property is significantly reduced. On the other hand, when there is too much Si content, a coarse crystallized substance and a precipitate will be formed and bending workability will fall remarkably. Therefore, Si is made 0.5 to 1.5% in range. A more preferred lower limit is 0.6%, and a more preferred upper limit is 1.4%.

Mg:0.3〜1.3%
Mgも、主要元素として、固溶強化と、塗装焼き付け処理などの人工時効処理時に、強度向上に寄与するMg−Si系析出物を形成して、時効硬化能を発揮し、パネルとしての必要耐力を得るための必須の元素である。Mg含有量が少なすぎると、Mg−Si系析出物の生成量が不足するため、BH性が著しく低下する。このためパネルとして必要な耐力が得られない。一方、Mg含有量が多すぎると、粗大な晶出物および析出物が形成されて、曲げ加工性が著しく低下する。したがって、Mgの含有量は0.3〜1.3%の範囲とする。さらに好ましい下限値は0.4%であり、さらに好ましい上限値は1.2%である。
Mg: 0.3 to 1.3%
Mg is also a major element, forming solid solution strengthening and Mg-Si-based precipitates that contribute to strength improvement during artificial aging treatment such as paint baking treatment, exhibiting age-hardening ability, and necessary proof strength as a panel It is an essential element for obtaining. If the Mg content is too small, the amount of Mg—Si-based precipitates is insufficient, so that the BH property is significantly lowered. For this reason, the proof stress required as a panel cannot be obtained. On the other hand, when there is too much Mg content, a coarse crystallized substance and a precipitate will be formed and bending workability will fall remarkably. Therefore, the Mg content is in the range of 0.3 to 1.3%. A more preferred lower limit is 0.4%, and a more preferred upper limit is 1.2%.

Sn:0.005〜0.2%
Snは必須の元素であり、室温において原子空孔を捕獲することで、室温でのMgやSiの拡散を抑制し、室温における強度増加(室温時効)を長期に亘って抑制し、この室温時効後の板の、パネルへのプレス成形時に、プレス成形性や、特にヘム加工性を向上させる効果がある。そして、一方では、成形されたパネルの塗装焼き付け処理などの人工時効処理時に、捕獲していた空孔を放出するため、逆にMgやSiの拡散を促進し、BH性を高くすることができる。
Sn: 0.005-0.2%
Sn is an essential element. By capturing atomic vacancies at room temperature, the diffusion of Mg and Si at room temperature is suppressed, and the increase in strength at room temperature (room temperature aging) is suppressed over a long period of time. There is an effect of improving press formability, particularly hemmability, at the time of press-molding a subsequent plate to a panel. And on the other hand, the trapped pores are released during the artificial aging treatment such as the paint baking treatment of the molded panel. On the contrary, the diffusion of Mg and Si can be promoted and the BH property can be increased. .

Snの含有量が少なすぎると、室温における強度増加を抑制できず、耐力が高くなって、ヘム加工性が劣化するだけでなく、BH処理時のMg−Si系析出物の生成量も減少して、BH性が低くなりやすい。したがって、Snの含有量は0.005〜0.2%の範囲とする。さらに好ましい下限値は0.01%であり、さらに好ましい上限値は0.18%である。   If the Sn content is too small, the increase in strength at room temperature cannot be suppressed, the yield strength becomes high, the hemmability deteriorates, and the amount of Mg-Si-based precipitates generated during BH treatment also decreases. Therefore, the BH property tends to be low. Therefore, the Sn content is in the range of 0.005 to 0.2%. A more preferred lower limit is 0.01%, and a more preferred upper limit is 0.18%.

但し、これらのSnの効果は、Snが固溶して初めて発揮される。このために、本発明では、後述する通り、残渣抽出法により測定した、Snの必要固溶量を確保する。   However, these effects of Sn are exhibited only when Sn is dissolved. Therefore, in the present invention, as will be described later, the necessary solid solution amount of Sn measured by the residue extraction method is ensured.

したがって、本発明のSnを含有したAl−Mg−Si系アルミニウム合金板は、Snの固溶という点で、組織的にも特性的にも、Snを含有しないAl−Mg−Si系アルミニウム合金板と比較して大きく異なる。また、同じように(同じ量)Snを含有したAl−Mg−Si系アルミニウム合金板であっても、中間焼鈍などの製造条件が違えば、Snの固溶量が異なり、通常の板の製造条件(常法)では、Snが化合物として析出しやすく、固溶量が著しく低い(少ない)ために、その組織は互いに大きく異なる。このため、同じように(同じ量)Snを含有していても、本発明のような高いレベルで室温時効を抑制するとともに、BH性やヘム加工性を向上させる効果のある組織が得られるとは限らない。   Therefore, the Al—Mg—Si based aluminum alloy sheet containing Sn of the present invention is an Al—Mg—Si based aluminum alloy sheet that does not contain Sn in terms of structure and characteristics in terms of solid solution of Sn. It is very different compared to Similarly, even if it is an Al—Mg—Si-based aluminum alloy plate containing Sn (the same amount), if the production conditions such as intermediate annealing are different, the solid solution amount of Sn is different, and the production of a normal plate Under conditions (ordinary method), Sn is likely to precipitate as a compound, and the amount of solid solution is remarkably low (small). For this reason, even if it contains Sn in the same manner (the same amount), it is possible to obtain a structure having an effect of suppressing room temperature aging at a high level as in the present invention and improving BH properties and hemmability. Is not limited.

(組織)
本発明の6000系アルミニウム合金板の組織について、以下に説明する。
(Organization)
The structure of the 6000 series aluminum alloy plate of the present invention will be described below.

Sn固溶量の目安:
本発明では、前記したSnの効果を発揮させるために必要な、Snの固溶量を確保することを特徴とする。このSnの固溶量確保の目安(基準)として、この板のSn含有量から、熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を差し引いたSnの量が0.005質量%以上とする。熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える、不溶性の残渣化合物とは析出物であり、これに含まれるSn含有量とは、板が合金組成として含有するSnのうちで、固溶したSnを除き、析出物として析出したSnの量を示す。したがって、この板の合金組成としてのSn含有量から、熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を差し引いたSnの量とは、本発明ではSnの固溶量を意味する。
Standard of Sn solid solution amount:
The present invention is characterized by securing the solid solution amount of Sn necessary for exhibiting the effect of Sn described above. As a guideline (standard) for securing the solid solution amount of Sn, the Sn content contained in the residual compound having a particle size of more than 0.1 μm separated by the residue extraction method using hot phenol is subtracted from the Sn content of the plate. The amount of Sn is 0.005 mass% or more. The insoluble residue compound having a particle size of more than 0.1 μm separated by the residue extraction method using hot phenol is a precipitate, and the Sn content contained in this is the Sn contained in the alloy composition of the plate The solid Sn content is excluded, and the amount of Sn deposited as a precipitate is shown. Therefore, the amount of Sn obtained by subtracting the Sn content contained in the residual compound having a particle size of more than 0.1 μm separated by the residue extraction method using hot phenol from the Sn content as the alloy composition of this plate is In the invention, it means the solid solution amount of Sn.

前記差し引いたSnの量が0.005質量%以上であれば、析出するSnが少なく、Snの固溶量が、添加したSnの前記効果を発揮できるに足る量であることを示している。一方、この差し引いたSnの量が0.005質量%未満になると、Snの固溶量が、添加したSnの前記効果を発揮しないような少ない量であることを示している。   If the amount of the subtracted Sn is 0.005% by mass or more, the amount of precipitated Sn is small, and the solid solution amount of Sn is an amount sufficient to exhibit the effect of the added Sn. On the other hand, when the amount of Sn subtracted is less than 0.005% by mass, the solid solution amount of Sn is a small amount that does not exhibit the effect of the added Sn.

なお、前記差し引いたSnの量(Snの固溶量)の上限は、残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量(析出するSnの量)が0となる場合である。すなわち、この板の含有するSnが全量マトリックス中に固溶している場合であり、板のSn含有量と、前記差し引いたSnの量とが同じとなる場合である。ただ、Snを一定以上添加あるいは含有した場合、常法ではSnは析出しやすく、Snを全て固溶させることは、効率的な(工業的な)製造限界からは困難である。したがって、前記差し引いたSnの量(Snの固溶量)の実際の上限は、板の合金組成としてのSn含有量よりも小さい値となり、具体的には、前記差し引いたSnの上限は0.15質量%程度となる。   In addition, the upper limit of the subtracted amount of Sn (the solid solution amount of Sn) is the Sn content (amount of Sn deposited) contained in the residue compound having a particle size of more than 0.1 μm separated by the residue extraction method. This is a case of 0. That is, this is the case where the Sn contained in the plate is in solid solution in the matrix, and the case where the Sn content of the plate is the same as the subtracted amount of Sn. However, when Sn is added or contained in a certain amount or more, Sn is likely to precipitate in the usual method, and it is difficult to dissolve all Sn from the efficient (industrial) production limit. Therefore, the actual upper limit of the subtracted Sn amount (Sn solid solution amount) is smaller than the Sn content as the alloy composition of the plate. It becomes about 15 mass%.

本発明では、後述する残渣抽出法のやり方を用いて、粒子サイズが0.1μmを超える残渣化合物(析出物)として析出したSnの量を再現性良く正確に測定でき、同時に、前記合金組成としてのSn含有量から、この析出したSnの量を差し引くことによって、Snの固溶量を代替的(間接的)に測定できることを見出した。また、この残渣抽出法による残渣量を利用したSn固溶量の評価は、実際のSn(固溶したSn)の発揮する効果と良く相関することも知見した。   In the present invention, the amount of Sn deposited as a residue compound (precipitate) with a particle size exceeding 0.1 μm can be accurately measured with good reproducibility using the method of residue extraction method described later, and at the same time, as the alloy composition It was found that the solid solution amount of Sn can be measured alternatively (indirectly) by subtracting the precipitated Sn amount from the Sn content. It was also found that the evaluation of the Sn solid solution amount using the residue amount by this residue extraction method correlates well with the effect exhibited by actual Sn (solid solution Sn).

汎用される残渣抽出法においては、通常、固液をろ過分離するフィルターのメッシュを0.1μmとし、液体から分離する粒子(固体)のサイズの境界の基準を0.1μmとして分離、区分けする。そして、0.1μmを超える残渣化合物を析出物としてみなす(取り扱う)一方、0.1μm以下のものを合金元素が溶解する溶液(固溶状態)として見なす(取り扱う)。ここで、分離される残渣化合物が0.1μm以下のより微細になるほど、ナノレベルの固溶状態に近づいて、固溶か析出かの判別が難しく、固溶量あるいは析出物との相関や、発揮される効果との相関が無くなる。これは、ろ液側の元素の含有量を測定して、それをその元素の固溶量とする場合も同様である。したがって、汎用される残渣抽出法においては、合金組成としての、その元素の含有量から、分離された粒子サイズが0.1μmを超える残渣化合物に含まれる、その元素の含有量を差し引いたものを、その元素の固溶量とみなすことが多い。   In a commonly used residue extraction method, the filter is usually separated and classified by setting the filter mesh for separating and separating solid liquid to 0.1 μm, and setting the boundary of the size of particles (solid) separated from the liquid to 0.1 μm. Then, residual compounds exceeding 0.1 μm are regarded (handled) as precipitates, while those having a size of 0.1 μm or less are regarded (handled) as a solution (solid solution state) in which the alloy elements are dissolved. Here, as the residue compound to be separated becomes finer than 0.1 μm or less, it approaches a nano-level solid solution state, and it is difficult to determine whether it is a solid solution or a precipitate. There is no correlation with the effect. The same applies to the case where the element content on the filtrate side is measured and used as the solid solution amount of the element. Therefore, in the widely used residue extraction method, the content of the element as the alloy composition is obtained by subtracting the content of the element contained in the residual compound whose separated particle size exceeds 0.1 μm. This is often regarded as the solid solution amount of the element.

したがって、本発明でも、これを踏襲し、粒子のサイズを0.1μmによって分離、区分けし、0.1μmを超えるものを残渣化合物として、(正確に言うと)Snの析出物とみなし、前記合金組成としてのSn含有量から、この析出した(析出とみなした)Snの量を差し引いたものを、(正確に言うと)Snの固溶量としてみなして規定している。   Accordingly, in the present invention, this is followed, and the particle size is separated and classified by 0.1 μm, and those exceeding 0.1 μm are regarded as residual compounds (to be precise) as Sn precipitates. A value obtained by subtracting the amount of precipitated Sn (presumed to be precipitated) from the Sn content as a composition is defined as a solid solution amount of Sn (to be exact).

前記規定の通り、Snの固溶量を確保して初めて、室温における原子空孔の捕獲による、室温でのMgやSiの拡散の抑制や、室温における強度増加(室温時効)を長期に亘って抑制の効果が発揮される。この結果、この室温時効後の板のパネルへのプレス成形時に、プレス成形性や、特にヘム加工性が向上する。また、成形されたパネルの塗装焼き付け処理などの人工時効処理時に、前記捕獲していた空孔を放出する効果も発揮され、MgやSiの拡散を促進して、BH性を高くすることができる。   As stated above, it is not until the solid solution amount of Sn is secured that the diffusion of Mg and Si at room temperature and the increase in strength at room temperature (room temperature aging) are captured over a long period of time by trapping atomic vacancies at room temperature. The suppression effect is exhibited. As a result, the press formability, particularly the hem workability, is improved at the time of press forming the panel after aging at room temperature onto the panel. In addition, during the artificial aging treatment such as paint baking treatment of the molded panel, the effect of releasing the trapped holes is also exhibited, and the diffusion of Mg and Si can be promoted to increase the BH property. .

抽出残渣法:
Snの固溶量を測定する抽出残渣法は次のように行う。先ず、分解フラスコにフェノールを入れて加熱した後、測定対象となる各供試板試料を、この分解フラスコに移し入れて加熱分解する。次に、ベンジルアルコールを加えた後、吸引ろ過してフィルター上の未溶解残渣を捕集した。捕集した残渣は、ベンジルアルコールとメタノールで洗浄して、Snの含有量を定量分析する。この定量分析には、原子吸光分析法(AAS)や誘導結合プラズマ発光分析法(ICP−OES)などを適宜用いる。前記吸引ろ過には、前記した通り、メッシュ(捕集粒子径)が0.1μmでφ47mmのメンブレンフィルターを用いる。そして、この粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を、合金組成としてのSn含有量から差し引き、Snの固溶量(質量%)として計算する。この測定と計算は、供試板の任意の10箇所について行い(試料を10個採取し)、これら各試料のSnの固溶量(質量%)を平均化する。
Extraction residue method:
The extraction residue method for measuring the solid solution amount of Sn is performed as follows. First, after putting phenol into a decomposition flask and heating, each sample plate sample to be measured is transferred to this decomposition flask and thermally decomposed. Next, after adding benzyl alcohol, suction filtration was performed to collect undissolved residue on the filter. The collected residue is washed with benzyl alcohol and methanol, and the Sn content is quantitatively analyzed. For this quantitative analysis, atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), or the like is appropriately used. As described above, a membrane filter having a mesh (collected particle diameter) of 0.1 μm and a diameter of 47 mm is used for the suction filtration. Then, the Sn content contained in the residual compound having a particle size exceeding 0.1 μm is subtracted from the Sn content as the alloy composition, and calculated as the solid solution amount (mass%) of Sn. This measurement and calculation are performed at any 10 locations on the test plate (10 samples are collected), and the solid solution amount (mass%) of Sn in each sample is averaged.

(製造方法)
次ぎに、本発明アルミニウム合金板の製造方法について以下に説明する。本発明アルミニウム合金板は、製造工程自体は常法あるいは公知の方法であり、上記6000系成分組成のアルミニウム合金鋳塊を鋳造後に均質化熱処理し、熱間圧延、冷間圧延が施されて所定の板厚とされ、更に溶体化焼入れなどの調質処理が施されて製造される。
(Production method)
Next, a method for producing the aluminum alloy plate of the present invention will be described below. The aluminum alloy sheet of the present invention is a conventional process or a known process, and the aluminum alloy ingot having the above-mentioned 6000 series component composition is subjected to homogenization heat treatment after casting, and then subjected to hot rolling and cold rolling to obtain a predetermined process. It is manufactured by being subjected to a tempering treatment such as solution hardening and quenching.

但し、これらの製造工程中で、Snを固溶させるためには、後述する通り、鋳造時の平均冷却速度制御に加えて、冷間圧延途中の中間焼鈍を規定する好ましい条件とする。このような中間焼鈍条件としなければ、Snを固溶させることが難しくなる。   However, in order to dissolve Sn in these manufacturing steps, as described later, in addition to the average cooling rate control during casting, a preferable condition for defining intermediate annealing during cold rolling is set. Unless such intermediate annealing conditions are used, it is difficult to make Sn dissolve.

(溶解、鋳造冷却速度)
先ず、溶解、鋳造工程では、上記6000系成分組成範囲内に溶解調整されたアルミニウム合金溶湯を、連続鋳造法、半連続鋳造法(DC鋳造法)等の通常の溶解鋳造法を適宜選択して鋳造する。ここで、本発明で規定するようにSnを固溶させるためには、鋳造時の平均冷却速度について、液相線温度から固相線温度までを30℃/分以上と、できるだけ大きく(速く)することが好ましい。
(Dissolution, casting cooling rate)
First, in the melting and casting process, an ordinary molten casting method such as a continuous casting method and a semi-continuous casting method (DC casting method) is appropriately selected for the molten aluminum alloy adjusted to be dissolved within the above-mentioned 6000 series component composition range. Cast. Here, in order to dissolve Sn as defined in the present invention, the average cooling rate during casting is as large as possible (fast) from the liquidus temperature to the solidus temperature of 30 ° C./min or more. It is preferable to do.

このような、鋳造時の高温領域での温度(冷却速度)制御を行わない場合、この高温領域での冷却速度は必然的に遅くなる。このように高温領域での平均冷却速度が遅くなった場合、この高温領域での温度範囲で粗大に生成する晶出物の量が多くなって、鋳塊の板幅方向,厚さ方向での晶出物のサイズや量のばらつきも大きくなる。この結果、本発明の規定範囲に、Snを固溶させることができなくなる可能性が高くなる。   When such temperature (cooling rate) control in the high temperature region during casting is not performed, the cooling rate in this high temperature region is inevitably slow. Thus, when the average cooling rate in the high temperature region becomes slow, the amount of crystallized material generated coarsely in the temperature range in this high temperature region increases, and in the plate width direction and thickness direction of the ingot. Variations in the size and amount of crystallized material also increase. As a result, there is a high possibility that Sn cannot be dissolved in the prescribed range of the present invention.

(均質化熱処理)
次いで、前記鋳造されたアルミニウム合金鋳塊に、熱間圧延に先立って、均質化熱処理を施す。この均質化熱処理(均熱処理)は、組織の均質化、すなわち、鋳塊組織中の結晶粒内の偏析をなくすことを目的とする。この目的を達成する条件であれば、特に限定されるものではなく、通常の1回または1段の処理でも良い。
(Homogenization heat treatment)
Next, the cast aluminum alloy ingot is subjected to a homogenization heat treatment prior to hot rolling. The purpose of this homogenization heat treatment (soaking) is to homogenize the structure, that is, eliminate segregation in crystal grains in the ingot structure. The conditions are not particularly limited as long as the object is achieved, and normal one-stage or one-stage processing may be performed.

均質化熱処理温度は、500℃以上で融点未満、均質化時間は4時間以上の範囲から適宜選択される。この均質化温度が低いと結晶粒内の偏析を十分に無くすことができず、これが破壊の起点として作用するために、伸びフランジ性や曲げ加工性が低下する。この後、直ちに熱間圧延を開始又は、適当な温度まで冷却保持した後に熱間圧延を開始しても良い。   The homogenization heat treatment temperature is appropriately selected from the range of 500 ° C. or more and less than the melting point, and the homogenization time is 4 hours or more. When this homogenization temperature is low, segregation within the crystal grains cannot be sufficiently eliminated, and this acts as a starting point of fracture, so that stretch flangeability and bending workability are deteriorated. Thereafter, the hot rolling may be started immediately, or the hot rolling may be started after cooling to an appropriate temperature.

この均質化熱処理を行った後、300℃〜500℃の間を20〜100℃/hの平均冷却速度で室温まで冷却し、次いで20〜100℃/hの平均加熱速度で350℃〜450℃まで再加熱し、この温度域で熱間圧延を開始することもできる。   After performing this homogenization heat treatment, it is cooled to room temperature at an average cooling rate of 20-100 ° C / h between 300 ° C and 500 ° C, and then 350 ° C-450 ° C at an average heating rate of 20-100 ° C / h. It is possible to reheat up to this temperature and start hot rolling in this temperature range.

この均質化熱処理後の平均冷却速度および、その後の再加熱速度の条件を外れると、粗大なMg−Si化合物が形成される可能性が高くなり、Snの効果発揮以前に、前提として必要な、6000系アルミニウム合金板の、強度や伸びなどの基本的な機械的性質が低下する。   When the average cooling rate after the homogenization heat treatment and the subsequent reheating rate are not satisfied, there is a high possibility that a coarse Mg-Si compound is formed. Basic mechanical properties such as strength and elongation of the 6000 series aluminum alloy plate are lowered.

(熱間圧延)
熱間圧延は、圧延する板厚に応じて、鋳塊 (スラブ) の粗圧延工程と、仕上げ圧延工程とから構成される。これら粗圧延工程や仕上げ圧延工程では、リバース式あるいはタンデム式などの圧延機が適宜用いられる。
(Hot rolling)
Hot rolling is composed of an ingot (slab) rough rolling process and a finish rolling process according to the thickness of the rolled sheet. In these rough rolling process and finish rolling process, a reverse or tandem rolling mill is appropriately used.

この際、熱延(粗圧延)開始温度が固相線温度を超える条件では、バーニングが起こるため熱延自体が困難となる。また、熱延開始温度が350℃未満では熱延時の荷重が高くなりすぎ、熱延自体が困難となる。したがって、熱延開始温度は350℃〜固相線温度、更に好ましくは400℃〜固相線温度の範囲とする。   At this time, under conditions where the hot rolling (rough rolling) start temperature exceeds the solidus temperature, burning occurs and thus the hot rolling itself becomes difficult. On the other hand, when the hot rolling start temperature is less than 350 ° C., the load during hot rolling becomes too high, and the hot rolling itself becomes difficult. Therefore, the hot rolling start temperature is set to 350 ° C. to the solidus temperature, more preferably 400 ° C. to the solidus temperature.

(熱延板の焼鈍)
この熱延板の冷間圧延前の焼鈍 (荒鈍) は必ずしも必要ではないが、結晶粒の微細化や集合組織の適正化によって、成形性などの特性を更に向上させる為に実施しても良い。
(Hot rolled sheet annealing)
Annealing (roughening) of the hot-rolled sheet before cold rolling is not always necessary, but it can be performed to further improve properties such as formability by refining crystal grains and optimizing the texture. good.

(冷間圧延)
冷間圧延では、上記熱延板を圧延して、所望の最終板厚の冷延板 (コイルも含む) に製作する。但し、結晶粒をより微細化させるためには、パス数に関わらず、合計の冷間圧延率は60%以上であることが望ましい。
(Cold rolling)
In cold rolling, the hot-rolled sheet is rolled to produce a cold-rolled sheet (including a coil) having a desired final thickness. However, in order to further refine the crystal grains, the total cold rolling rate is desirably 60% or more regardless of the number of passes.

(中間焼鈍)
この冷間圧延前(熱延後)か、冷間圧延の途中(パス間)で、板を480℃以上、融点以下の高温で0.1〜10秒間保持し、次いで、3℃/秒以上の平均冷却速度で室温まで強制冷却(急冷)する中間焼鈍を、繰り返して2回以上行い、それまでの熱延工程などで化合物として生成したSnを固溶させることが好ましい。常法ではSnは析出しやすく、一旦析出したSnを再度固溶させることもなかなか難しく、本発明で規定するようにSnを固溶させるためには、このような高温での短時間の熱処理を複数回行う必要がある。ただし、この条件範囲内であれば、複数回の熱処理条件を同じとせずとも、変えても良い。
(Intermediate annealing)
Before this cold rolling (after hot rolling) or in the middle of cold rolling (between passes), the plate is held at a high temperature of 480 ° C. or higher and below the melting point for 0.1 to 10 seconds, and then 3 ° C./second or higher. It is preferable to repeat the intermediate annealing forcibly cooling (rapid cooling) to room temperature at an average cooling rate of 2 times or more, so that Sn produced as a compound in the hot rolling step or the like is dissolved. In ordinary methods, Sn is likely to precipitate, and it is difficult to re-dissolve Sn once precipitated. In order to dissolve Sn as defined in the present invention, a short heat treatment at such a high temperature is required. Must be done multiple times. However, as long as it is within this condition range, a plurality of heat treatment conditions may not be the same, but may be changed.

この中間焼鈍条件につき、板の温度が480℃未満では、例え、中間焼鈍を2回以上行っても、Snの固溶量が不足する。これは、焼鈍温度や急冷条件が範囲内である中間焼鈍の回数が1回のみでも同じである。また、保持時間は、0.1秒などの瞬間的も含む短時間で良いが、10秒を超えると板の機械的性質が著しく低下する。また、焼鈍後の冷却を、3℃/秒以上の平均冷却速度とする、空冷やミスト、水冷などによる、室温までの強制冷却(急冷)としないと、すなわち平均冷却速度が3℃/秒未満では、一旦固溶したSnが再析出して化合物化してしまう。   With regard to the intermediate annealing conditions, if the plate temperature is lower than 480 ° C., even if the intermediate annealing is performed twice or more, the Sn solid solution amount is insufficient. This is the same even if the number of intermediate annealings in which the annealing temperature and the rapid cooling conditions are within the range is only one. Further, the holding time may be a short time including an instantaneous time such as 0.1 second, but if it exceeds 10 seconds, the mechanical properties of the plate are remarkably deteriorated. In addition, if the cooling after annealing is not the forced cooling (rapid cooling) to room temperature by air cooling, mist, water cooling or the like with an average cooling rate of 3 ° C./second or more, that is, the average cooling rate is less than 3 ° C./second. Then, Sn once dissolved is reprecipitated and compounded.

このような条件での焼鈍は、急冷も含めて、バッチ炉では無理で、板を巻き戻しながら炉に通板して巻き取る、連続的な熱処理炉が必要となる。このように、急冷が可能な連続焼鈍を用いる場合でも、本発明者らの知見によれば、1回だけの連続焼鈍だけでは、どうしてもSnの固溶量が不足する。このため、連続焼鈍による中間焼鈍を2回以上繰り返すものとする。但し、連続焼鈍の繰り返しは、回数が増すほど、製造工程の効率を大きく低下させるので、繰り返し回数は2回程度とすることが好ましい。   Annealing under such conditions is impossible in a batch furnace, including rapid cooling, and requires a continuous heat treatment furnace that passes the sheet through the furnace and winds it up. Thus, even when continuous annealing capable of rapid cooling is used, according to the knowledge of the present inventors, the solid solution amount of Sn is inevitably insufficient by only one continuous annealing. For this reason, the intermediate annealing by continuous annealing shall be repeated twice or more. However, the number of repetitions of continuous annealing is preferably about 2 because the efficiency of the manufacturing process is greatly reduced as the number of repetitions increases.

(溶体化および焼入れ処理)
冷間圧延後、溶体化焼入れ処理を行う。溶体化処理焼入れ処理については、通常の連続熱処理ラインによる加熱,冷却でよく、特に限定はされない。ただ、各元素の十分な固溶量を得ること、および板組織の結晶粒はより微細であることが望ましいことから、520℃以上、溶融温度以下の溶体化処理温度に、加熱速度5℃/秒以上で加熱して、0〜10秒保持する条件で行う。そして、溶体化温度から焼入れ停止温度までの平均冷却速度を3℃/秒以上とする。冷却速度が小さいと、冷却中にMg−Si系化合物などが析出しやすくなり、プレス成形や曲げ加工時の割れの起点となり易く、これら成形性が低下する。この冷却速度を確保するために、焼入れ処理は、ファンなどの空冷、ミスト、スプレー、浸漬等の水冷手段や条件を各々選択して用いる。
(Solution and quenching)
After cold rolling, a solution hardening treatment is performed. The solution treatment and quenching treatment may be heating and cooling by a normal continuous heat treatment line, and is not particularly limited. However, since it is desirable to obtain a sufficient solid solution amount of each element and that the crystal grains of the plate structure are finer, the solution treatment temperature is 520 ° C. or higher and the melting temperature or lower. The heating is performed for at least 2 seconds, and the condition is maintained for 0 to 10 seconds. And the average cooling rate from solution temperature to quenching stop temperature shall be 3 ° C / second or more. When the cooling rate is low, Mg-Si compounds and the like are likely to be precipitated during cooling, which tends to be the starting point of cracks during press molding and bending, and these moldability is reduced. In order to ensure this cooling rate, the quenching treatment is performed by selecting water cooling means and conditions such as air cooling such as a fan, mist, spray, and immersion, respectively.

ちなみに、この溶体化焼入れ処理や、前記熱延後の荒鈍条件も、温度などが前記中間焼鈍条件と近似するが、前記中間焼鈍が無いか、あるいは、行っていても前記520℃以上の温度などの諸条件を満たさなければ、この溶体化焼入れ処理や前記熱延後の荒鈍を行っただけでは、Snを前記必要量、あるいは前記規定量だけ、固溶させることができない。   Incidentally, the solution annealing treatment and the roughing conditions after the hot rolling are also similar in temperature and the like to the intermediate annealing conditions, but the intermediate annealing does not exist or is performed at a temperature of 520 ° C. or higher. If the various conditions such as the above are not satisfied, Sn cannot be dissolved in the required amount or the specified amount only by performing the solution quenching process or the roughening after the hot rolling.

(再加熱処理)
続いて、BH処理時に生成するMg−Si系化合物の核となる原子の集合体(クラスタ)を形成させるために、溶体化焼入れ処理後に、予備時効処理(再加熱処理)を行う。板の到達温度(実体温度)は80〜150℃の温度範囲かつ、保持時間は3〜50時間の範囲であることが望ましい。再加熱処理後の室温までの冷却は、放冷でも、生産の効率化のために前記焼入れ時の冷却手段を用いて強制急冷しても良い。
(Reheating treatment)
Subsequently, a pre-aging treatment (reheating treatment) is performed after the solution hardening treatment in order to form an aggregate (cluster) of atoms serving as nuclei of the Mg—Si compound generated during the BH treatment. The ultimate temperature (substance temperature) of the plate is desirably in the temperature range of 80 to 150 ° C., and the holding time is desirably in the range of 3 to 50 hours. The cooling to room temperature after the reheating treatment may be allowed to cool or may be forcibly quenched using the cooling means at the time of quenching in order to increase production efficiency.

以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも可能であり、それらは何れも本発明の技術的範囲に含まれる。   EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to implement, and they are all included in the technical scope of the present invention.

次に本発明の実施例を説明する。Snの固溶量が異なる6000系アルミニウム合金板を、前記中間焼鈍条件によって作り分けて、本発明で規定するSnの固溶量を調査した。そして、この板を室温に100日間保持後のBH性(塗装焼付け硬化性)や、ヘム加工性も評価した。この結果を表2に示す。   Next, examples of the present invention will be described. 6000 series aluminum alloy plates having different Sn solid solution amounts were prepared according to the intermediate annealing conditions, and the Sn solid solution amount defined in the present invention was investigated. And BH property (coating bake hardenability) after holding this board at room temperature for 100 days and hem workability were also evaluated. The results are shown in Table 2.

これらアルミニウム合金板の具体的な製造条件は以下の通りとした。表1に示す各組成のアルミニウム合金鋳塊を、DC鋳造法により共通して溶製した。この際、各例とも共通して、鋳造時の平均冷却速度について、液相線温度から固相線温度までを50℃/分とした。なお、各例の6000系アルミニウム合金板の組成を示す、表1中の各元素の含有量の表示において、各元素における数値をブランクとしている表示は、その含有量が検出限界以下で、これらの元素を含まない0%であることを示す。   The specific production conditions for these aluminum alloy plates were as follows. Aluminum alloy ingots having respective compositions shown in Table 1 were commonly melted by DC casting. At this time, in common with each example, the average cooling rate during casting was set to 50 ° C./min from the liquidus temperature to the solidus temperature. In addition, in the display of the content of each element in Table 1 showing the composition of the 6000 series aluminum alloy plate of each example, the display in which the numerical value of each element is blank is the content below the detection limit. It shows 0% not containing any elements.

続いて、前記鋳塊を、各例とも共通して、540℃×4時間均熱処理した後、熱間粗圧延を開始した。そして、各例とも共通して、続く仕上げ圧延にて、厚さ2.5mmまで熱延し、熱間圧延板とした。熱間圧延後のアルミニウム合金板を、各例とも共通して、500℃×1分の荒焼鈍を施した後、冷間圧延のパス途中(パス間)に、表2に示すように、連続焼鈍炉による中間焼鈍を、その回数や温度、平均冷却速度などを変えた、種々の条件で行って、最終的に厚さ1.0mmの冷延板(製品板)とした。   Subsequently, the ingot was subjected to soaking at 540 ° C. for 4 hours in common with each example, and then hot rough rolling was started. And in each example, it was hot rolled to a thickness of 2.5 mm in the subsequent finish rolling to obtain a hot rolled sheet. As shown in Table 2, the aluminum alloy plate after hot rolling was subjected to rough annealing at 500 ° C. for 1 minute in common with each example, and then during the cold rolling pass (between passes) as shown in Table 2. Intermediate annealing with an annealing furnace was performed under various conditions with different numbers, temperatures, average cooling rates, and the like, and finally a cold-rolled sheet (product sheet) having a thickness of 1.0 mm was obtained.

更に、これらの各冷延板を、各例とも共通して、560℃の硝石炉にて溶体化処理を行い、目標温度に到達後10秒保持し、水冷にて焼入れ処理した。この焼入れ後直ちに、100℃で5時間保持する予備時効処理を行った(保持後は冷却速度0.6℃/時間で徐冷)。   Further, these cold-rolled sheets were subjected to solution treatment in a 560 ° C. glass stone furnace in common with each example, held for 10 seconds after reaching the target temperature, and quenched by water cooling. Immediately after this quenching, a preliminary aging treatment was carried out by holding at 100 ° C. for 5 hours (after holding, slow cooling at a cooling rate of 0.6 ° C./hour).

これらの調質処理直後の各板から供試板 (ブランク) を切り出し、各供試板の組織(Snの固溶量)を測定した。また、前記調質処理後に100日間室温で放置した後の各板から供試板 (ブランク) を切り出し、各供試板の強度(AS耐力)とBH性とを調査した。これらの結果を表2に示す。   A test plate (blank) was cut out from each plate immediately after the tempering treatment, and the structure (solid solution amount of Sn) of each test plate was measured. Further, a test plate (blank) was cut out from each plate after being left at room temperature for 100 days after the tempering treatment, and the strength (AS proof stress) and BH property of each test plate were examined. These results are shown in Table 2.

(供試板の組織)
調質処理直後の各供試板のSnの固溶量として、前記した測定方法により、この板のSn含有量から、熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を差し引いたSnの量(質量%)を調査した。
(Test plate structure)
As the solid solution amount of Sn in each test plate immediately after the tempering treatment, a residue having a particle size of more than 0.1 μm separated from the Sn content of this plate by the residue extraction method using hot phenol by the measurement method described above. The amount (mass%) of Sn after subtracting the Sn content contained in the compound was investigated.

(引張試験)
前記引張試験は、前記調質処理後に100日間室温で放置した後の各供試板から、各々JISZ2201の5号試験片(25mm×50mmGL×板厚)を採取し、室温にて引張り試験を行った。このときの試験片の引張り方向を圧延方向の直角方向とした。引張り速度は、0.2%耐力までは5mm/分、耐力以降は20mm/分とした。機械的特性測定のN数は5とし、各々平均値で算出した。なお、前記BH後の耐力測定用の試験片には、この試験片に、板のプレス成形を模擬した2%の予歪をこの引張試験機により与えた後に、前記BH処理を行った。
(Tensile test)
In the tensile test, JISZ2201 No. 5 test pieces (25 mm × 50 mmGL × plate thickness) were collected from each test plate after being left at room temperature for 100 days after the tempering treatment, and a tensile test was performed at room temperature. It was. The tensile direction of the test piece at this time was the direction perpendicular to the rolling direction. The tensile speed was 5 mm / min up to 0.2% proof stress and 20 mm / min after proof stress. The N number for the measurement of mechanical properties was 5, and each was calculated as an average value. The test piece for measuring the yield strength after the BH was subjected to the BH treatment after giving a pre-strain of 2% simulating press forming of the plate to the test piece by the tensile tester.

(BH性)
各供試板を各々共通して、前記100日間の室温時効させた後に、185℃×20分の人工時効硬化処理した後(BH後)の、供試板の0.2%耐力(BH後耐力)を前記引張試験により求めた。そして、これら0.2%耐力同士の差(耐力の増加量)から各供試板のBH性を評価し、0.2%耐力の増加量が100MPa以上ある場合を合格とした。
(BH property)
Each test plate was commonly aged at room temperature for 100 days and then subjected to an artificial age hardening treatment at 185 ° C. for 20 minutes (after BH). Yield strength) was determined by the tensile test. Then, the BH property of each test plate was evaluated from the difference between these 0.2% proof stresses (increased proof stress), and the case where the increased 0.2% proof stress was 100 MPa or more was regarded as acceptable.

(ヘム加工性)
ヘム加工性は、前記100日間室温放置後の各供試板について行った。試験は、30mm幅の短冊状試験片を用い、ダウンフランジによる内曲げR1.0mmの90°曲げ加工後、1.0mm厚のインナを挟み、折り曲げ部を更に内側に、順に約130度に折り曲げるプリヘム加工、180度折り曲げて端部をインナに密着させるフラットヘム加工を行った。
(Heme workability)
Hem workability was measured for each test plate after standing at room temperature for 100 days. In the test, a strip-shaped test piece with a width of 30 mm was used, and after bending 90 ° with an internal bend R of 1.0 mm by a down flange, a 1.0 mm thick inner was sandwiched, and the bent portion was further bent inwardly to about 130 degrees. Pre-hem processing was performed, and flat hem processing was performed in which the end was closely attached to the inner by bending 180 degrees.

このフラットヘムの曲げ部(縁曲部)の、肌荒れ、微小な割れ、大きな割れの発生などの表面状態を目視観察し、以下の基準にて目視評価し、基準0〜2までを合格とした。
0;割れ、肌荒れ無し、1;軽度の肌荒れ、2;深い肌荒れ、3;微小表面割れ、4;線状に連続した表面割れ、5;破断
The surface state of the flat hem bent portion (edge curved portion) such as rough skin, minute cracks, and large cracks was visually observed, visually evaluated according to the following criteria, and criteria 0 to 2 were accepted. .
0: No cracking, rough skin, 1: Mild rough skin, 2; Deep rough skin, 3: Small surface crack, 4; Continuous surface crack, 5: Break

表2の番号1〜4、12〜23に示す各発明例は、本発明成分組成範囲内(表1の合金番号1〜13)で、かつ、中間焼鈍を含めて前記した好ましい条件範囲内で製造している。このため、これら各発明例は、表2に示す通り、本発明で規定する、板のSn含有量から、残渣抽出法により分離された残渣化合物に含まれるSn含有量を差し引いた、Snの量(質量%)を満たし、含有するSnの析出が抑制されており、Snの固溶量が高い。   Each invention example shown in numbers 1 to 4 and 12 to 23 in Table 2 is within the composition range of the present invention (alloy numbers 1 to 13 in Table 1), and within the preferable condition range described above including intermediate annealing. Manufacture. For this reason, as shown in Table 2, each of these invention examples is the Sn content obtained by subtracting the Sn content contained in the residue compound separated by the residue extraction method from the Sn content of the plate as defined in the present invention. (Mass%) is satisfied, precipitation of contained Sn is suppressed, and the solid solution amount of Sn is high.

この結果、前記各発明例は、表2に示す通り、前記調質処理後100日の長期の室温時効後であっても、As耐力が90〜110MPaのレベルであっても、BH(ベークハード)後の耐力が190MPaのレベルで、耐力差が100MPa以上と、BH性に優れている。また、前記調質処理後の長期の室温時効後であってもAs耐力が比較的低いために、自動車パネルなどへのプレス成形性に優れ、ヘム加工性にも優れている。   As a result, as shown in Table 2, each of the above-mentioned invention examples is BH (baked hard) even after a long-term room temperature aging for 100 days after the tempering treatment or even when the As proof strength is at a level of 90 to 110 MPa. ) The yield strength is 190 MPa and the yield strength difference is 100 MPa or more. Further, even after long-term aging after the tempering treatment, the As yield strength is relatively low, so that it is excellent in press formability to automobile panels and the like, and is excellent in hem workability.

また、表2から分る通り、同じ表1の合金番号1を用いても、中間処理条件の違いによって、Snの固溶状態が大きく異なり、特性が大きく異なっている。すなわち、発明例1〜4の中でも、中間焼鈍温度が比較的低く、平均冷却速度も比較的小さい発明例1、2に比して、中間焼鈍温度が比較的高く、平均冷却速度も比較的大きい発明例3、4は、板のSn含有量から、残渣抽出法により分離された残渣化合物に含まれるSn含有量を差し引いた、Snの量(質量%)が多く、含有するSnの析出が抑制されており、Snの固溶量が高い。この結果、発明例1、2に比して、発明例3、4は、前記調質処理後100日の長期の室温時効後であっても、BH後の耐力差がより高く、BH性がより優れている。   Further, as can be seen from Table 2, even when the same alloy number 1 in Table 1 is used, the solid solution state of Sn is greatly different and the characteristics are greatly different depending on the difference in intermediate processing conditions. That is, among Invention Examples 1 to 4, the intermediate annealing temperature is relatively low and the average cooling rate is relatively small, compared to Invention Examples 1 and 2, the intermediate annealing temperature is relatively high and the average cooling rate is also relatively large. Invention Examples 3 and 4 have a large amount of Sn (% by mass) obtained by subtracting the Sn content contained in the residue compound separated by the residue extraction method from the Sn content of the plate, and suppress the precipitation of the contained Sn. The amount of Sn dissolved is high. As a result, compared to Invention Examples 1 and 2, Invention Examples 3 and 4 have a higher yield strength difference after BH and a higher BH property even after 100 days after room temperature aging. Better.

これに対して、これら発明例と同じ表1の合金番号1を用いている、表2の比較例5〜11は、中間焼鈍条件が好ましい範囲から外れる例である。このため、これら比較例は、本発明で規定する、板のSn含有量から、残渣抽出法により分離された残渣化合物に含まれるSn含有量を差し引いた、Snの量(質量%)が少なすぎて、含有するSnの析出が抑制できておらず、Snの固溶量が低い。このため、同じ合金組成である前記発明例に比して、自動車パネルなどへのプレス成形性やヘム加工性に劣り、耐力差が100MPa未満と、BH性も劣っている。   On the other hand, Comparative Examples 5-11 of Table 2 which uses the same alloy number 1 of Table 1 as these invention examples are examples in which intermediate annealing conditions deviate from a preferable range. For this reason, in these comparative examples, the Sn content (% by mass) obtained by subtracting the Sn content contained in the residue compound separated by the residue extraction method from the Sn content of the plate defined in the present invention is too small. Thus, precipitation of contained Sn cannot be suppressed, and the solid solution amount of Sn is low. For this reason, compared with the said invention example which is the same alloy composition, it is inferior to the press moldability and hem workability to a motor vehicle panel etc., and a yield strength difference is less than 100 Mpa, and BH property is also inferior.

比較例5は中間焼鈍していない。
比較例6は、温度、保持時間、平均冷却速度の条件は満たすが、1回のみの中間焼鈍である。
比較例7は、2回目の中間焼鈍は、温度、保持時間、平均冷却速度の条件を満たしているが、1回目の中間焼鈍の温度が400℃と、480℃未満であり低すぎる。
比較例8は、1回目の中間焼鈍は、温度、保持時間、平均冷却速度の条件を満たしているが、2回目の中間焼鈍の温度が400℃と、480℃未満であり低すぎる。
比較例9は、1回目、2回目の中間焼鈍の温度が460℃と、2回とも480℃未満で低すぎる。
比較例10、11は、1回目、2回目の中間焼鈍の温度、保持時間は条件を満たしているが、1回目か2回目かの平均冷却速度が遅すぎる。
Comparative Example 5 is not subjected to intermediate annealing.
Although the comparative example 6 satisfy | fills the conditions of temperature, holding time, and average cooling rate, it is an intermediate annealing only once.
In Comparative Example 7, the second intermediate annealing satisfies the conditions of temperature, holding time, and average cooling rate, but the temperature of the first intermediate annealing is 400 ° C. and less than 480 ° C., which is too low.
In Comparative Example 8, the first intermediate annealing satisfies the conditions of temperature, holding time, and average cooling rate, but the temperature of the second intermediate annealing is 400 ° C. and less than 480 ° C., which is too low.
In Comparative Example 9, the temperature of the first and second intermediate annealings is 460 ° C., which is both less than 480 ° C. and too low.
In Comparative Examples 10 and 11, the temperature and holding time of the first and second intermediate annealing satisfy the conditions, but the average cooling rate of the first or second time is too slow.

また、表2の比較例24〜29は、中間焼鈍条件を含めて好ましい範囲で製造しているものの、表1の合金番号14〜19を用いており、必須元素のMg、Si、Snの含有量が各々本発明範囲を外れている。このため、これら比較例24〜29は、表2に示す通り、各発明例に比して、特に100日間室温保持後のAs耐力が比較的高すぎて自動車パネルなどへのプレス成形性やヘム加工性に劣るか、BH性が劣っている。また、比較例27は、Snが多すぎ、熱延時に割れが発生して熱延板自体が製造できなかった。   Moreover, although the comparative examples 24-29 of Table 2 are manufactured in the preferable range including intermediate annealing conditions, they use the alloy numbers 14-19 of Table 1, and contain Mg, Si, Sn of an essential element Each amount is outside the scope of the present invention. For this reason, as shown in Table 2, these Comparative Examples 24 to 29 have a relatively high As yield strength after holding at room temperature for 100 days, as compared with each invention example. It is inferior in workability or BH property. In Comparative Example 27, Sn was too much, and cracking occurred during hot rolling, so that the hot rolled sheet itself could not be manufactured.

比較例24は表1の合金14であり、Siが少なすぎる。
比較例25は表1の合金15であり、Siが多すぎる。
比較例26は表1の合金16であり、Snが少なすぎる
比較例27は表1の合金17であり、Snが多すぎる。
比較例28は表1の合金18であり、Mgが少なすぎる。
比較例29は表1の合金19であり、Mgが多すぎる。
The comparative example 24 is the alloy 14 of Table 1, and there is too little Si.
The comparative example 25 is the alloy 15 of Table 1, and there is too much Si.
The comparative example 26 is the alloy 16 of Table 1, and Sn is too little. The comparative example 27 is the alloy 17 of Table 1, and there is too much Sn.
Comparative example 28 is alloy 18 of Table 1, and there is too little Mg.
The comparative example 29 is the alloy 19 of Table 1, and there is too much Mg.

以上の実施例の結果から、Snを含む6000系アルミニウム合金板の長期室温時効後のヘム加工性やBH性向上に対して、本発明で規定する組成やSnの固溶量とすることや、中間焼鈍条件などの好ましい製造条件の、臨界的な意義乃至効果が裏付けられる。   From the results of the above examples, for the heme workability and BH improvement after long-term aging of the Sn-containing 6000 series aluminum alloy plate, the composition defined in the present invention and the Sn solid solution amount, The critical significance or effect of preferable manufacturing conditions such as intermediate annealing conditions is supported.

本発明によれば、長期室温時効後のBH性や成形性を兼備する6000系アルミニウム合金板を提供できる。この結果、自動車、船舶あるいは車両などの輸送機、家電製品、建築、構造物の部材や部品用として、また、特に、自動車などの輸送機の部材に6000系アルミニウム合金板の適用を拡大できる。   ADVANTAGE OF THE INVENTION According to this invention, the 6000 series aluminum alloy plate which has BH property and formability after long-term room temperature aging can be provided. As a result, the application of the 6000 series aluminum alloy plate can be expanded as a member for a transport device such as an automobile, a ship or a vehicle, a home appliance, a building or a structure, and particularly as a member for a transport device such as an automobile.

Claims (2)

質量%で、Mg:0.3〜1.3%、Si:0.5〜1.5%、Sn:0.005〜0.2%を各々含み、残部がAlおよび不可避的不純物からなるAl−Mg−Si系アルミニウム合金板であって、この板のSn含有量から、熱フェノールによる残渣抽出法により分離された粒子サイズが0.1μmを超える残渣化合物に含まれるSn含有量を差し引いたSnの量が0.005質量%以上であることを特徴とする成形用アルミニウム合金板。   In mass%, Mg: 0.3 to 1.3%, Si: 0.5 to 1.5%, Sn: 0.005 to 0.2%, respectively, with the balance being Al and inevitable impurities Al -Mg-Si-based aluminum alloy plate, which is obtained by subtracting the Sn content contained in the residual compound having a particle size of more than 0.1 μm separated by the residue extraction method using hot phenol from the Sn content of this plate An aluminum alloy sheet for forming, characterized in that the amount of is 0.005 mass% or more. 前記アルミニウム合金板が、更に、Mn:1.0%以下(但し、0%を含まず)、Cu:1.0%以下(但し、0%を含まず)、Fe:1.0%以下(但し、0%を含まず)、Cr:0.3%以下(但し、0%を含まず)、Zr:0.3%以下(但し、0%を含まず)、V:0.3%以下(但し、0%を含まず)、Ti:0.05%以下(但し、0%を含まず)、Zn:1.0%以下(但し、0%を含まず)、Ag:0.2%以下(但し、0%を含まず)の1種または2種以上を含む請求項1に記載の成形用アルミニウム合金板。   The aluminum alloy plate further comprises Mn: 1.0% or less (excluding 0%), Cu: 1.0% or less (excluding 0%), Fe: 1.0% or less ( However, 0% is not included), Cr: 0.3% or less (however, 0% is not included), Zr: 0.3% or less (however, 0% is not included), V: 0.3% or less (However, 0% is not included), Ti: 0.05% or less (However, 0% is not included), Zn: 1.0% or less (However, 0% is not included), Ag: 0.2% The forming aluminum alloy sheet according to claim 1, comprising one or more of the following (excluding 0%).
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