JP2008246508A - Bending method of aluminum alloy material - Google Patents

Bending method of aluminum alloy material Download PDF

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JP2008246508A
JP2008246508A JP2007088799A JP2007088799A JP2008246508A JP 2008246508 A JP2008246508 A JP 2008246508A JP 2007088799 A JP2007088799 A JP 2007088799A JP 2007088799 A JP2007088799 A JP 2007088799A JP 2008246508 A JP2008246508 A JP 2008246508A
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bending
aluminum alloy
panel
hem
processing
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Yasuo Takagi
康夫 高木
Kazuhide Matsumoto
和秀 松元
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Kobe Steel Ltd
株式会社神戸製鋼所
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<P>PROBLEM TO BE SOLVED: To provide a working method capable of subjecting even a 6000 Al alloy sheet to sever bending such as flat hemming of a small bending radius. <P>SOLUTION: When bending an outer panel 1 of the 6000 Al alloy sheet, an outer panel peripheral edge 1a to be bent is previously subjected to bending of ≥20% on an amount of working strain loaded on the material surface on the outer side of the bending, and further, the outer panel peripheral edge 1a is subjected to a low-temperature heat treatment under specific conditions, then to objective severely bending 180° bending so as to make the peripheral edge 1c or 1d. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、室温時効硬化して成形性が低下したような6000系アルミニウム合金材のヘム加工などの曲げ加工性を回復させた、アルミニウム合金材(以下、アルミニウムを単にAlとも言う)の曲げ加工方法に関するものである。   The present invention is a bending process of an aluminum alloy material (hereinafter, aluminum is also simply referred to as “Al”) that has recovered the bending processability of a 6000 series aluminum alloy material whose formability has decreased due to age hardening at room temperature. It is about the method.
なお、本発明で言うアルミニウム合金材とは、圧延された板、あるいは、この板をプレス成形したパネル、または、押出された開断面、閉断面などの形材、管材などを含むものである。また、6000系アルミニウム合金とは、JISに規格化された6000系に相当する組成(範囲内の組成、近似する組成)を有するアルミニウム合金を言う。   The aluminum alloy material referred to in the present invention includes a rolled plate, a panel obtained by press-molding this plate, an extruded open section, a closed section, or the like, a tube material, and the like. Further, the 6000 series aluminum alloy refers to an aluminum alloy having a composition (composition within range, approximate composition) corresponding to 6000 series standardized by JIS.
従来から、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Al合金パネル材として、成形性に優れたAl−Mg系のAA乃至JIS規格に規定された(規格を満足する)5000系や、成形性や焼付硬化性に優れたAl−Mg−Si系の6000系アルミニウム合金板材(圧延板材)が使用され始めている。   Conventionally, panels such as outer panels (outer panels) and inner panels (inner panels) of panel structures such as automobile hoods, fenders, doors, roofs, and trunk lids have been made of thin and high-strength Al alloy panels. Al-Mg-based AA or JIS standard (satisfying the standard) 5,000-based Al-Mg-based AA or JIS standard, and Al-Mg-Si-based 6000-based aluminum alloy sheet excellent in formability and bake hardenability (Rolled sheet material) has begun to be used.
この6000系アルミニウム合金板材は、優れた時効硬化能を有しているため、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、成形後の焼付塗装処理など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必要な強度を確保できる利点がある。この特性は、特に、過剰Si型の6000系アルミニウム合金が優れている。この過剰Si型の6000系アルミニウム合金は、基本的には、Si、Mgを必須として含み、かつSi/Mg重量比が1以上である、Al−Mg−Si系アルミニウム合金である。   This 6000 series aluminum alloy sheet has excellent age-hardening ability, so it secures formability by reducing the yield strength during press molding and bending, and at the time of artificial age-hardening treatment such as baking coating after molding. There is an advantage that the strength can be improved by age-hardening by heating and the required strength can be ensured. This characteristic is particularly excellent in an excess Si type 6000 series aluminum alloy. This excess Si type 6000 series aluminum alloy is basically an Al—Mg—Si series aluminum alloy containing Si and Mg as essential elements and having a Si / Mg weight ratio of 1 or more.
前記した自動車パネル構造体の、フードやドアなどのアウタパネルでは、プレス成形後に、アウタパネルの周縁を略180度折り曲げて(折り返して)、成形加工後のインナパネルの縁との接合を行う、ヘミング加工(はぜ折り加工、以下ヘム加工と言う)が行われる。通常、これらアウタパネルのヘム加工は、その前のプレス成形と連動して行われる。即ち、絞り成形、トリム工程後、約90度までパネル周縁部をフランジ曲げされる(ダウンフランジ工程)までが、一連のアウタパネルのプレス成形工程として行われる。そして、この後、成形されたアウタパネルと、別途プレス成形されたインナパネルとを組み合わせ、アウタパネルのフランジ部にてインナパネル周縁部を挟み込むようにして、アウタパネルのフランジ部が180度まで曲げ加工(ヘム加工)される。   In the outer panel such as a hood and a door of the above-described automobile panel structure, hemming is performed after the press molding, and the outer panel is bent (turned back) by about 180 degrees and joined to the edge of the inner panel after the molding. (Helding fold processing, hereinafter referred to as hem processing) is performed. Usually, the hem processing of these outer panels is performed in conjunction with the previous press molding. That is, after the drawing and trimming processes, the peripheral edge of the panel is bent to about 90 degrees (down flange process) as a series of outer panel press forming processes. After that, the molded outer panel and the separately press-molded inner panel are combined, and the outer panel flange is sandwiched by the outer panel flange so that the outer panel flange is bent to 180 degrees (hem) Processed).
このヘム加工の概要を図1(a)〜(d)に示す。同図から分かる通り、ヘム加工はプレス成形工程および外周トリム工程後、図1(a)のダウンフランジ工程を経て得られたアウタパネルを、以下に詳述する、図1(b)のプリヘム工程を経て、図1(c)のフラットヘム工程か、図1(d)のロープヘム工程かの選択により基本的に行われる。   An outline of this hem processing is shown in FIGS. As can be seen from the figure, the hem processing is performed after the press panel process and the outer periphery trim process, and the outer panel obtained through the down flange process of FIG. After that, it is basically performed by selecting the flat hem process of FIG. 1 (c) or the rope hem process of FIG. 1 (d).
まず、図1(a)のダウンフランジ工程は、ダイス3aと板押さえ5aにより固定した、成形加工後のアウタパネル1の縁(周縁部)1aを、ポンチ4aにより、直角(90°)に近い角度まで折り曲げる。   First, in the down flange process of FIG. 1 (a), the edge (peripheral edge) 1a of the outer panel 1 after the molding process, which is fixed by the die 3a and the plate retainer 5a, is close to a right angle (90 °) by the punch 4a. Bend until
次に図1(b)のプリヘム工程は、絞り工程やトリム工程等の成形加工後のインナパネル2の縁を、ダウンフランジ工程後のアウタパネル1の折り曲げ部に収容 (挿入) した後、アウタパネル1およびインナパネル2とをダイス3bと板押さえ5bにより固定し、アウタパネル1の縁(周縁部)1bを、ダイス3bとポンチ4bにより、更に約135°まで内側に折り曲げる。6bはアウタパネル1の折り曲げ部における端部 (周縁部、曲げ部) である。   Next, in the pre-hem process of FIG. 1B, after the edge of the inner panel 2 after the molding process such as the drawing process or the trim process is accommodated (inserted) in the bent portion of the outer panel 1 after the down flange process, the outer panel 1 The inner panel 2 is fixed by the die 3b and the plate presser 5b, and the edge (peripheral edge) 1b of the outer panel 1 is further bent inward to about 135 ° by the die 3b and the punch 4b. Reference numeral 6b denotes an end portion (peripheral portion, bent portion) in the bent portion of the outer panel 1.
更に、このプリヘム工程を経て、更にアウタパネル1の縁(周縁部)1bを180度まで曲げ加工するフラットヘム工程かロープヘム工程かの選択により行われる。図1(c)のフラットヘム工程や図1(d)のロープヘム工程は、アウタパネル1およびインナパネル2とを、板押さえ (図示せず) とダイス3c、3dにより固定するとともに、アウタパネル1の縁1c、1dを、ポンチ4c、4dにより、更に略180度(°)の角度まで内側に折り曲げ、フラットヘム又はロープヘムの折り曲げ部を形成する。このようにして、インナパネル2の縁と、フラットヘム又はロープヘム(180度折り曲げ部)の縁である、アウタパネル1の縁1c、1dとが接触して、両者が端部同士において接合されるとともに密着される。6c、6dはアウタパネル1 の折り曲げ部における端部 (周縁部、曲げ部、コーナー部) である。   Further, through the prehem process, the edge (periphery) 1b of the outer panel 1 is further selected by selecting a flat hem process or a rope hem process for bending the outer panel 1 to 180 degrees. In the flat hem process of FIG. 1C and the rope hem process of FIG. 1D, the outer panel 1 and the inner panel 2 are fixed to each other by a plate presser (not shown) and dies 3c and 3d. 1c and 1d are further bent inward by punches 4c and 4d to an angle of approximately 180 degrees (°) to form a bent portion of flat hem or rope hem. In this way, the edge of the inner panel 2 and the edges 1c and 1d of the outer panel 1 which are the edges of the flat hem or the rope hem (180-degree bent part) are in contact with each other, and both are joined at the ends. Close contact. Reference numerals 6c and 6d denote end portions (peripheral portion, bent portion, and corner portion) in the bent portion of the outer panel 1.
この内、図1(d)のロープヘム工程は、図1(c)のフラットヘム工程に比較して、ヘム縁曲部(折り曲げ部) の形状が、円弧状に膨らんだ、ロープ状の形状を有しており、シャープ乃至フラットなヘム形状ではなく、外観性も良くない。また、アウタパネルとインナパネルとの接触面積が少なく接合性や密着性に欠ける等の問題もある。   Among these, the rope hem process of FIG. 1 (d) has a rope-like shape in which the shape of the hem edge bent portion (bent part) swells in an arc shape compared to the flat hem process of FIG. 1 (c). It does not have a sharp or flat hem shape, and the appearance is not good. In addition, there is a problem that the contact area between the outer panel and the inner panel is small and the bonding property and adhesion are lacking.
このため、特に、外観や美観を重視する自動車部品などにおいては、ヘム加工の最終工程を、厳しい曲げ加工となる、図1(c)のフラットヘム工程により行うことが通常となっている。   For this reason, in particular, in automobile parts and the like that place importance on the appearance and aesthetics, the final process of hem processing is usually performed by the flat hem process of FIG.
近年、自動車パネル構造体のアウタパネルのキャラクターラインや形状は複雑になる傾向にあり、また、薄肉化に対応するためのAl合金パネルの高強度化も図られており、これらはいずれも、アルミニウム合金パネルのヘム加工性を低下させる。また、6000系アルミニウム合金材は、室温(常温)時効硬化が生じやすく、この素材側の時効硬化もアルミニウム合金パネルのヘム加工性を低下させる。   In recent years, the character line and shape of the outer panel of an automobile panel structure have tended to be complicated, and the strength of Al alloy panels has been increased to cope with the reduction in thickness. Reduces the hemmability of the panel. Further, the 6000 series aluminum alloy material is likely to be age-hardened at room temperature (room temperature), and the age-hardening on the material side also deteriorates the hem workability of the aluminum alloy panel.
このため、これらヘム加工性を低下させる環境や加工条件の変化に対し、Al合金パネルのヘム加工で形成されるフラットヘムの縁曲部には、後述する特許文献2、3などにも詳細に開示されている、肌荒れ、微小な割れ、比較的大きな割れ(程度順に記載)等の不良が生じ易くなり、パネル構造体への適用ができなくなる可能性が高くなる。   For this reason, in response to changes in the environment and processing conditions that reduce these hemmability, the edge curve portion of the flat hem formed by hem processing of the Al alloy panel is also described in detail in Patent Documents 2 and 3 described later. The disclosed defects such as rough skin, minute cracks, relatively large cracks (described in order of degree) are likely to occur, and the possibility of being unable to be applied to the panel structure increases.
これに対して、従来から、ヘム加工工程側や、Al合金板の素材側で、前記ヘム部 (縁曲部、折り曲げ部) のしわや割れなどの不良発生を防止する技術も種々提案されている。   On the other hand, various techniques for preventing the occurrence of defects such as wrinkles and cracks in the hem part (edge bent part, bent part) on the hem processing process side and the Al alloy sheet material side have been proposed. Yes.
例えば、高強度なアルミニウム合金板のフラットヘム加工において、前記図4図4(a)のダウンフランジ工程において、アウタパネル材に形成されるフランジ曲げ部の円弧半径Rd (ダイスの肩半径) を大きくし、より具体的には、アルミニウム合金板の板厚との関係で、折り曲げ半径Rdを0.8t〜1.8t (但しt はアルミニウム合金板の板厚) として、前記不良の発生を防止することなどが提案されている (特許文献1参照)。   For example, in flat hem processing of a high-strength aluminum alloy plate, the arc radius Rd (the shoulder radius of the die) of the flange bending portion formed in the outer panel material is increased in the down flange process of FIG. 4 (a). More specifically, in relation to the thickness of the aluminum alloy plate, the bending radius Rd is set to 0.8 t to 1.8 t (where t is the thickness of the aluminum alloy plate) to prevent the occurrence of the defect. It has been proposed (see Patent Document 1).
また、アルミニウム合金アウタパネル材のフラットヘム加工方法であって、アウタパネル材を、特定組成のSi過剰型のAl- Mg- Si系アルミニウム合金板とするとともに、この板の特性として、特定条件での人工時効処理後の耐力などを規定して、アルミニウム合金パネルのヘム加工性を向上させることも提案されている (特許文献2参照)。   Also, there is provided a flat hem processing method for an aluminum alloy outer panel material, wherein the outer panel material is a Si-rich Al-Mg-Si aluminum alloy plate having a specific composition, and the characteristics of the plate are artificial under certain conditions. It has also been proposed to improve the hem workability of an aluminum alloy panel by specifying the yield strength after aging treatment (see Patent Document 2).
更に、アルミニウム合金パネルにおける円弧半径が1500以下の円弧状周縁部のヘム加工方法であって、前記円弧状周縁部を略180度折り曲げて、パネル周縁部形状に対応する形状のヘム周縁部を持つフランジを形成するに際し、このフランジの折り曲げ長さを7mm以下とする、アルミニウム合金パネルのヘム加工方法も提案されている(特許文献3参照)。   Furthermore, it is a hem processing method of an arc-shaped peripheral edge portion having an arc radius of 1500 or less in an aluminum alloy panel, wherein the arc-shaped peripheral edge portion is bent by approximately 180 degrees to have a hem peripheral edge shape corresponding to the panel peripheral edge shape. There has also been proposed a hem processing method for an aluminum alloy panel in which a bending length of the flange is set to 7 mm or less when the flange is formed (see Patent Document 3).
これに対して、室温(常温)時効硬化が生じた6000系アルミニウム合金材に対し、1%以上の加工歪みを予め与えた後に50〜150℃の温度に加熱する時効硬化回復処理を行なって、ヘム加工などの成形を行うことも提案されている(特許文献4参照)。
特公昭63−2690号公報 特開2003−39124号公報 特開2004−98154号公報 特開2005−240083号公報
On the other hand, an age hardening recovery treatment for heating to a temperature of 50 to 150 ° C. after preliminarily giving a processing strain of 1% or more to a 6000 series aluminum alloy material in which age hardening has occurred at room temperature (room temperature), It has also been proposed to perform hem processing or the like (see Patent Document 4).
Japanese Patent Publication No. 63-2690 JP 2003-39124 A JP 2004-98154 A Japanese Patent Laid-Open No. 2005-240083
しかし、これら従来技術による、アルミニウム合金板の板厚との関係でのヘム折り曲げ半径の規定やフランジの折り曲げ長さの規定、あるいはAl合金板の特性などの、板の素材側での改善だけでは、アルミニウム合金パネルのヘム加工性を改善するには限界がある。このため、どうしてもヘム加工工程側でも改善する必要がある。   However, these conventional technologies only improve the material side of the plate, such as the definition of the hem bending radius and the flange bending length in relation to the thickness of the aluminum alloy plate, or the characteristics of the Al alloy plate. There is a limit to improving the hemmability of aluminum alloy panels. For this reason, it is necessary to improve the hem processing step.
また、前記した通り、特に6000系Al合金は、その優れた時効硬化能ゆえに、Al合金材自体の製造後、前記各用途に使用されるまでの間に、室温( 常温) 時効硬化が生じやすい。このような室温時効した6000系Al合金パネル材では、ヘム加工時に曲げ先端が鋭角的に折れた坐屈形状となり易く、ヘム加工性が著しく低下する問題もある。   In addition, as described above, 6000 series Al alloys are particularly susceptible to age-hardening at room temperature (room temperature) after the production of the Al alloy material itself and before being used for each application because of its excellent age-hardening ability. . Such a 6000 series Al alloy panel material aged at room temperature tends to have a buckled shape in which the bending tip is bent acutely at the time of hem processing, and there is a problem that the hem workability is remarkably lowered.
これに対して、前記特許文献4では、確かに、室温(常温)時効硬化が生じた6000系アルミニウム合金材に対しては、加工歪みを予め与えた後に、比較的低温での加熱によって、時効硬化が回復され、ヘム加工などの成形性が向上する。   On the other hand, in the above-mentioned Patent Document 4, it is true that 6000 series aluminum alloy material that has undergone room temperature (room temperature) age hardening has been subjected to aging by heating at a relatively low temperature after preliminarily giving processing strain. Curing is recovered and moldability such as hem processing is improved.
しかし、室温(常温)時効硬化が生じておらず、比較的成形性が良い6000系アルミニウム合金材でも、成形中の割れを生じるような、加工条件が厳しい曲げ加工工程では、前記特許文献4でも十分な曲げ加工を得ることができない。即ち、前記したアウタパネルのヘム加工がプレス成形と連動して行われる際、このプレス成形工程中のパネル周縁部のフランジ曲げ工程での加工条件が厳しい場合には、前記特許文献4でも十分な曲げ加工を得ることができない。   However, even in the 6000 series aluminum alloy material that does not cause age hardening at room temperature (room temperature) and has relatively good formability, even in the bending process that has severe processing conditions such as cracking during molding, A sufficient bending process cannot be obtained. That is, when the hem processing of the outer panel described above is performed in conjunction with the press molding, if the processing conditions in the flange bending process of the peripheral edge of the panel during the press molding process are severe, even in the above-mentioned Patent Document 4, sufficient bending is performed. Processing cannot be obtained.
具体的に、この加工条件が厳しい場合とは、板(成形パネル)のフランジ曲げ後に曲げ外側の材料表面に負荷される加工歪み量が20%以上となるような、プレス成形における予歪み量が大きいか又は曲げ半径が小さい曲げ加工である。このような場合には、最終ヘム加工後に板(成形パネル)周縁部(フランジ)の曲げ部分(コーナ部分)において割れが生じやすい。   Specifically, when the processing conditions are severe, the amount of pre-strain in press molding is such that the amount of processing strain applied to the material surface outside the bend after flange bending of the plate (molded panel) is 20% or more. Bending with a large or small bending radius. In such a case, cracks are likely to occur in the bent portion (corner portion) of the peripheral portion (flange) of the plate (molded panel) after the final hem processing.
したがって、6000系アルミニウム合金板(成形パネル)を、このような加工条件が厳しい曲げ加工する場合には、設計形状(成形形状)などの設計変更や、工程や時間などの効率化を犠牲にして成形加工条件を緩和する、等の手段を採用していたのが実情である。   Therefore, when bending a 6000 series aluminum alloy plate (molded panel) with such severe processing conditions, it is at the expense of design changes such as the design shape (molded shape) and efficiency such as process and time. The actual situation is that measures such as relaxation of molding processing conditions have been adopted.
本発明はこの様な事情に着目してなされたものであって、その目的は、このような加工条件が厳しい曲げ加工工程であっても、そして、曲げ加工されるアルミニウム合金材が、室温時効硬化したような6000系などのアルミニウム合金パネルであっても、良好にヘム加工などの曲げ加工ができる加工方法を提供しようとするものである。   The present invention has been made paying attention to such a situation, and the purpose thereof is to be a bending process in which such processing conditions are severe, and the aluminum alloy material to be bent is subjected to room temperature aging. It is an object of the present invention to provide a processing method capable of satisfactorily performing bending processing such as hem processing even for a hardened aluminum alloy panel such as 6000 series.
この目的を達成するために、本発明アルミニウム合金材の曲げ加工方法の要旨は、6000系アルミニウム合金材を曲げ加工するに際し、曲げ加工されるアルミニウム合金材に、その曲げ外側の材料表面に負荷される加工歪み量が20%以上である曲げ加工を予め施し、このアルミニウム合金材に対して、更に、1℃/分以上の昇温速度で50〜150℃に加熱し、1分を超え、20分以下の範囲で保持する熱処理を行った後に、曲げ加工を行うことである。   In order to achieve this object, the gist of the bending method of the aluminum alloy material of the present invention is that when bending a 6000 series aluminum alloy material, the aluminum alloy material to be bent is loaded on the material surface outside the bending. The aluminum alloy material is preliminarily subjected to a bending process with a processing strain amount of 20% or more, and further heated to 50 to 150 ° C. at a temperature rising rate of 1 ° C./min or more, exceeding 1 minute, 20 Bending is performed after performing a heat treatment that is held within a range of less than a minute.
ここで、本発明において、前記加工歪み量は、後述する通り、次式にて近似的に算出でき、前記加工歪み量は、この近似的に算出した値である。
ε=(r i +t )/(r i +t/2)+ε0 、ここで、r i ;内曲げ半径、t ;板厚、ε0 ;曲げ加工前に負荷される予歪み、である。
Here, in the present invention, as will be described later, the processing strain amount can be approximately calculated by the following equation, and the processing strain amount is a value calculated approximately.
ε = (r i + t) / (r i + t / 2) + ε 0 , where r i is the inner bending radius, t is the plate thickness, ε 0 is the pre-strain applied before bending.
上記本発明の要旨において、前記熱処理後30分以内に前記曲げ加工を行うことが好ましい。また、前記アルミニウム合金材が板であり、前記加工歪み量を生じる条件での曲げ加工が、この板のプレス成形中に施され、前記熱処理後の曲げ加工がヘム加工であることが好ましい。更に、前記アルミニウム合金材がアウタパネルであり、前記加工歪み量を生じる条件での曲げ加工がヘム加工におけるダウンフランジ加工であり、前記熱処理後の曲げ加工がヘム加工におけるプリヘム加工を経た180度曲げ加工であることが好ましい。   In the gist of the present invention, it is preferable to perform the bending process within 30 minutes after the heat treatment. Further, it is preferable that the aluminum alloy material is a plate, bending under a condition that generates the amount of processing strain is performed during press forming of the plate, and the bending after the heat treatment is hem processing. Further, the aluminum alloy material is an outer panel, the bending process under the condition for generating the processing strain is a down flange process in the hem process, and the bending process after the heat treatment is a 180 degree bending process through a pre-hem process in the hem process. It is preferable that
本発明では、曲げ加工されるアルミニウム合金材に、その曲げ外側の材料表面に負荷される加工歪み量が20%以上である曲げ加工を予め施し、更に、前記目的とする曲げ加工前に、特定条件下で熱処理を行う。   In the present invention, the aluminum alloy material to be bent is preliminarily subjected to a bending process in which the amount of processing strain applied to the material surface outside the bend is 20% or more, and is further specified before the target bending process. Heat treatment is performed under the conditions.
この前段の曲げ加工と熱処理によって、低下した6000系アルミニウム合金材の曲げ加工性が回復される。この理由は、本発明における、前段の曲げ加工で導入された大きな加工歪みによって、一旦生成された転位のタングルが、続く特定条件下での熱処理によって、曲げ加工の良いセル構造に変化するゆえと考えられる。また、これと同時に、6000系アルミニウム合金材に特有の室温時効硬化によって、室温で形成され、曲げ加工性を低下させるMg、Siのクラスターの一部が消滅するためと考えられる。   The lowered bending workability of the 6000 series aluminum alloy material is recovered by this previous bending process and heat treatment. This is because, in the present invention, the tangles of dislocations once generated due to the large processing strain introduced in the previous bending process are changed into a cell structure with good bending process by the subsequent heat treatment under specific conditions. Conceivable. At the same time, it is considered that part of the Mg and Si clusters formed at room temperature and lowering the bending workability disappear due to room temperature age hardening characteristic of the 6000 series aluminum alloy material.
本発明によれば、製造から成形までに数カ月間以上の長期間放置されて、室温時効硬化したり、前工程としてのプレス成形などによって加工硬化されて低下した6000系アルミニウム合金材の曲げ加工性を回復できる。   According to the present invention, the bending workability of a 6000 series aluminum alloy material that has been left for a long period of time of several months or more from manufacture to forming and age-hardened at room temperature or reduced by work hardening by press forming as a pre-process, etc. Can be recovered.
しかも、上記本発明熱処理のような低い温度に加熱しても、6000系アルミニウム合金材の他の引張強度、耐力などの機械的性質の大幅な低下は一切無い。また、6000系アルミニウム合金材のベークハード性(人工時効硬化性)を低下させる悪影響もない。   Moreover, even when heated to a low temperature as in the heat treatment of the present invention, there is no significant decrease in other mechanical properties such as tensile strength and proof strength of other 6000 series aluminum alloy materials. Further, there is no adverse effect of reducing the bake hardness (artificial age hardening) of the 6000 series aluminum alloy material.
また、本発明における前記特定条件下での熱処理も、比較的低温、短時間の簡便な熱処理であるので、加熱手段も汎用されているものが使用可能であり、大幅な設備改造や、生産性を低下させることなく実施できる利点がある。   In addition, since the heat treatment under the specific conditions in the present invention is also a simple heat treatment at a relatively low temperature and in a short time, a heating means that is widely used can be used, and significant equipment modifications and productivity can be achieved. There is an advantage that can be implemented without lowering.
因みに、前記特許文献4の時効硬化回復処理を行う条件は、本発明における熱処理を行う条件に比して、予め与える加工歪みが、実施例において実際に与えている加工歪みとして、最大でも15%程度でしかない。   Incidentally, the condition for performing the age hardening recovery process of Patent Document 4 is that the processing strain given in advance is 15% at the maximum as the processing strain actually given in the embodiment as compared with the condition for performing the heat treatment in the present invention. It is only about.
また、通常の曲げ加工性改善のように、加工歪みを予め加えずに、単に加熱して焼きなます方法では、上記本発明における熱処理温度のような低温に加熱しても、常識的にも、室温時効硬化した6000系アルミニウム合金材の機械的な性質、特に、成形性は変化しない。しかし、上記加工歪みを予め与えた上で、このような低温に加熱すると、一旦低下した6000系アルミニウム合金材の曲げ加工性を回復できる。   Moreover, in the method of simply heating and annealing without adding processing distortion in advance, as in the usual improvement of bending workability, even if it is heated to a low temperature such as the heat treatment temperature in the present invention, it is common sense The mechanical properties of the 6000 series aluminum alloy material age-hardened at room temperature, particularly the formability, do not change. However, if the processing strain is applied in advance and then heated to such a low temperature, the bendability of the 6000 series aluminum alloy material once lowered can be recovered.
上記本発明における低温熱処理は、加工歪みを予め与えないと曲げ加工性の回復が発現しない点が特異であって、前記した6000系アルミニウム合金材を最低でも200℃以上の温度に加熱して成形加工する、温間あるいは熱間成形技術と、基本的な冶金的メカニズムを異にすることが分かる。   The low-temperature heat treatment in the present invention is unique in that the recovery of bending workability does not appear unless processing strain is given in advance, and the above-described 6000 series aluminum alloy material is heated to a temperature of at least 200 ° C. and formed. It can be seen that the basic metallurgical mechanism differs from the warm or hot forming technology to be processed.
以下に、本発明Al合金板の実施態様につき具体的に説明する。   Hereinafter, embodiments of the Al alloy plate of the present invention will be specifically described.
(曲げ加工)
本発明では、6000系アルミニウム合金材を曲げ加工するに際し、曲げ加工されるアルミニウム合金材には、前段として、その曲げ外側の材料表面に負荷される加工歪み量が20%以上である曲げ加工を予め施す。
(Bending)
In the present invention, when bending a 6000 series aluminum alloy material, the aluminum alloy material to be bent is subjected to a bending process in which a processing strain applied to the material surface outside the bending is 20% or more as a previous stage. Apply in advance.
これは、加工歪み量が20%以下であるような容易な曲げ加工条件では従来技術によって曲げ加工が可能であり、本発明での効果を特に発現する為に必要な条件である。この曲げ加工によって、これに続く熱処理による、後段の曲げ加工性向上効果を発揮させる。または、この前段の曲げ加工と続く熱処理によって、低下した6000系アルミニウム合金材の曲げ加工性を回復させる。   This is a necessary condition for particularly exhibiting the effect of the present invention, which can be bent by the conventional technique under an easy bending condition in which the amount of processing distortion is 20% or less. By this bending process, the effect of improving the subsequent bending workability by the subsequent heat treatment is exhibited. Alternatively, the lowered bending workability of the 6000 series aluminum alloy material is recovered by the preceding bending process and the subsequent heat treatment.
この本発明における加熱前(前段)の曲げ加工では、特に、加工歪量の上限は規定しないが、加工歪量が大き過ぎる場合には、この工程で6000系アルミニウム合金材に割れが発生する。このため、望ましくは、曲げ外側の板表面で50%以下とし、20〜50%の範囲とする。   In the bending process before heating (previous stage) in the present invention, the upper limit of the processing strain amount is not particularly defined, but if the processing strain amount is too large, the 6000 series aluminum alloy material is cracked in this step. For this reason, desirably, it is 50% or less on the plate surface outside the bend, and the range is 20 to 50%.
(加工歪み量のFEM数値解析)
ここで、上記加工歪み量は近似的に算出できる。即ち、図2に模式的に示す板の曲げ加工時(例えば90度曲げ)の状態において、図2のA−A' 〜B−B' 間の内曲げRに沿った部位のみで歪みが生じ、点線で示す板厚中心を中立軸と仮定した場合には、曲げ外表面に生じる歪み量εとして、前記加工歪み量は次式にて近似的に(簡易的に)算出される。
(FEM numerical analysis of machining strain)
Here, the processing strain amount can be approximately calculated. That is, in the state of bending of the plate schematically shown in FIG. 2 (for example, bending at 90 degrees), distortion occurs only at the site along the inner bend R between AA ′ and BB ′ of FIG. Assuming that the center of the thickness indicated by the dotted line is the neutral axis, the amount of processing strain is approximately (simplely) calculated as the amount of strain ε generated on the outer surface of the bend.
ε=(r i +t )/(r i +t/2)+ε0 、ここで、r i ;内曲げ半径、t ;板厚、ε0 ;曲げ加工前に負荷される予歪み、である。 ε = (r i + t) / (r i + t / 2) + ε 0 , where r i is the inner bending radius, t is the plate thickness, ε 0 is the pre-strain applied before bending.
この加工歪み量の近似値をより正確に検証するためには、特開2004−174521号公報などに開示された公知の手法が適用できる。例えば、PAM−STAMPなどのアルミニウム合金材の曲げ加工解析のための汎用FEM解析ソフトを用い、アルミニウム合金材をシェル要素で、金型を剛体近似して解析する。ここで、6000系アルミニウム合金材の曲げ加工の際の摩擦係数は0.14と一定に設定して行う。   In order to verify the approximate value of the processing strain more accurately, a known method disclosed in Japanese Patent Application Laid-Open No. 2004-174521 can be applied. For example, general-purpose FEM analysis software for bending processing analysis of an aluminum alloy material such as PAM-STAMP is used, and the aluminum alloy material is analyzed using a shell element and the mold is approximated to a rigid body. Here, the friction coefficient at the time of bending of the 6000 series aluminum alloy material is set to a constant value of 0.14.
(熱処理)
本発明では、この曲げ加工に続く熱処理によって、後段の曲げ加工性向上効果を得る。このための熱処理条件は、アルミニウム合金材に対して、1℃/分以上の昇温速度で50〜150℃に加熱し、1分を超え、20分以下の範囲で保持することとする。この熱処理は、後段の曲げ加工されるアルミニウム合金材に対して、素材全体でも、あるいは曲げ加工部分のみを行ってもよく、また、特に曲げ加工条件が厳しくなる部分を選択的に行ってもよい。
(Heat treatment)
In the present invention, the effect of improving the subsequent bending workability is obtained by the heat treatment subsequent to the bending process. The heat treatment condition for this is to heat the aluminum alloy material to 50 to 150 ° C. at a temperature rising rate of 1 ° C./min or more, and hold it in the range of more than 1 minute and 20 minutes or less. This heat treatment may be performed on the entire material or only the bent portion of the aluminum alloy material to be bent at the subsequent stage, or may be selectively performed at a portion where bending conditions are particularly severe. .
そして、加熱手段も、上記加熱(熱処理)部位に応じて、それがアルミニウム合金材の部分的であればヒータ、それがアルミニウム合金材の全体であれば加熱炉などという具合に、公知の加熱手段が適宜選択される。本発明では、前記した通り、比較的低温であるので、使用できる加熱手段の選択肢も広くなる。   The heating means is also a known heating means, depending on the heating (heat treatment) part, such as a heater if it is a partial aluminum alloy material, a heating furnace if it is a whole aluminum alloy material, etc. Is appropriately selected. In the present invention, as described above, since the temperature is relatively low, choices of heating means that can be used are widened.
加熱昇温速度が遅すぎる(小さすぎると)、加熱温度が低すぎる、加熱保持時間が短すぎると、熱処理を行ったとしても、後段の曲げ加工である、ヘム加工などにおける十分な曲げ加工性向上効果を得ることができない。   If the heating rate is too slow (too small), the heating temperature is too low, or the heating holding time is too short, even if heat treatment is performed, sufficient bending workability in hem processing, etc., which is the latter bending process The improvement effect cannot be obtained.
例えば、昇温速度が遅すぎると、実質的に加熱保持時間が20分を超えて長時間となる場合と同じとなってしまい、Mg、Siの化合物相が析出して硬度が増加し、却って曲げ加工性が低下してしまう。   For example, if the rate of temperature rise is too slow, it becomes substantially the same as the case where the heating and holding time exceeds 20 minutes and becomes a long time, and the compound phase of Mg and Si is precipitated to increase the hardness. Bending workability will decrease.
また、加熱温度が低すぎる、加熱保持時間が短すぎると、前記した前段の曲げ加工(加工歪み)で導入された転位のタングルが変化して生成する曲げ加工の良いセル構造の量が少なくなる。と同時に、6000系アルミニウム合金材に特有の室温時効硬化によって、室温で形成され、曲げ加工性を低下させるMg、Siのクラスターの消滅も少なくなる。このため、後段の対象とする(目標とする)曲げ加工である、ヘム加工などにおける十分な曲げ加工性向上効果を得ることができない。   Also, if the heating temperature is too low and the heating holding time is too short, the amount of the cell structure with good bending work produced by changing the tangles of dislocations introduced in the preceding bending work (working distortion) is reduced. . At the same time, due to room temperature age hardening specific to the 6000 series aluminum alloy material, the disappearance of Mg and Si clusters formed at room temperature and lowering the bending workability is also reduced. For this reason, it is not possible to obtain a sufficient bending workability improvement effect in hem processing or the like, which is a target bending process (target).
一方、加熱温度が高すぎる、あるいは加熱保持時間が長すぎても、後段の曲げ加工である、ヘム加工などにおける十分な曲げ加工性向上効果を得ることができない。例えば、加熱温度が高すぎると、Mg、Siの化合物相が析出して硬度が増加し、却って曲げ加工性が低下してしまう。   On the other hand, if the heating temperature is too high or the heating and holding time is too long, it is not possible to obtain a sufficient bending workability improvement effect in hem processing or the like, which is a subsequent bending process. For example, if the heating temperature is too high, a compound phase of Mg and Si is precipitated to increase the hardness, and on the contrary, the bending workability is lowered.
尚、本発明では加熱後の冷却速度は特に規定しないが、上記所定の加熱保持時間の範囲内とする観点からは、所定の加熱保持時間後は、加熱装置等の熱源から板を離すなどして、速やかに冷却することが望ましい。具体的には加熱保持後の冷却速度を1℃/分以上とすることが望ましい。   In the present invention, the cooling rate after heating is not particularly defined. However, from the viewpoint of keeping within the range of the predetermined heating and holding time, after the predetermined heating and holding time, the plate is separated from a heat source such as a heating device. It is desirable to cool quickly. Specifically, the cooling rate after heating and holding is preferably 1 ° C./min or more.
(熱処理後曲げ加工までの時間)
本発明では、上記熱処理後に、ヘム加工などの後段の曲げ加工を行うが、加熱後速やかに曲げ加工を行うことが望ましく、加熱処理後30分以内に後段の曲げ加工を行うことが好ましい。熱処理後30分を超えた後の曲げ加工では、熱処理後加熱を行わない場合よりは曲げ加工性が向上するものの、その向上効果が低下してしまう。
(Time to bend after heat treatment)
In the present invention, after the heat treatment, a subsequent bending process such as a hemming process is performed, but it is desirable to perform the bending process immediately after the heating, and it is preferable to perform the subsequent bending process within 30 minutes after the heating process. In the bending process after 30 minutes after the heat treatment, although the bending workability is improved as compared with the case where the heating is not performed after the heat treatment, the improvement effect is lowered.
(板における本発明曲げ加工工程)
本発明を6000系アルミニウム合金製外板 (アウタパネル) の場合について具体的に説明する。先ず、前記自動車アウタパネルなどとして、6000系アルミニウム合金板を張出や絞りあるいはトリム等のプレス成形してパネル化する。このプレス成形の際に、本発明の前段の曲げ加工として、その曲げ外側の材料表面に負荷される加工歪み量が20%以上であるような、前記した図1のヘム加工工程の内の、ダウンフランジ工程などのパネル周縁部を略90度に曲げる曲げ加工を予め施す。
(Invention bending process for plate)
The present invention will be specifically described in the case of a 6000 series aluminum alloy outer plate (outer panel). First, as the automobile outer panel or the like, a 6000 series aluminum alloy plate is formed into a panel by press forming such as overhanging, drawing or trimming. During the press molding, as the former bending process of the present invention, the processing strain applied to the material surface outside the bending is 20% or more of the hem processing step of FIG. 1 described above, A bending process for bending the peripheral edge of the panel, such as a down flange process, to approximately 90 degrees is performed in advance.
次いで、新規に追加される工程として、前段の曲げ加工を予め施されたパネルに、本発明の前記所定条件の熱処理を施す。その後、直ちに(熱処理後30分以内にの意味)、前記略90度に折り曲げられた(ダウンフランジ工程で加工された)パネル周縁部を、外板 (アウタパネル) として、更に、前記した図1のヘム加工工程の後段の曲げ加工を施す。即ち、前記ダウンフランジ工程に続き、このパネル周縁部を、略135度に曲げる前記プリヘム工程を経て、前記フラットヘム工程あるいは前記ロープドヘム工程などの180度ヘム加工(曲げ加工)が施される。   Next, as a newly added step, the heat treatment under the predetermined condition of the present invention is performed on the panel that has been subjected to the previous bending process in advance. Immediately thereafter (meaning within 30 minutes after the heat treatment), the peripheral edge of the panel (processed in the down flange process) bent to approximately 90 degrees was used as an outer panel (outer panel), and the above-described FIG. Bending the latter part of the hem processing process. That is, following the down flange process, a 180 degree hem process (bending process) such as the flat hem process or the roped hem process is performed through the pre-hem process for bending the peripheral edge of the panel to approximately 135 degrees.
なお、6000系アルミニウム合金アウタパネルの場合、本発明の前段の曲げ加工手段としては、前記した図1のダウンフランジ工程などの、パネル周縁部の曲げ加工などでないと、その曲げ外側の材料表面に負荷される加工歪み量が20%以上とはできない。例えば、加工歪みをアルミニウム合金材に付与する手段としては、他に、ロールや引張 (テンションレベラ) などの矯正機などを利用して張力を与える方法もあるが、これでは、前記加工歪み量を20%以上と大きくはできない。即ち、このように前記加工歪み量を大きくするためには、曲げ加工金型を用いて曲げ加工しなければ困難である。   In the case of a 6000 series aluminum alloy outer panel, if the bending means in the previous stage of the present invention is not the bending process of the peripheral edge of the panel such as the down flange process of FIG. The amount of processing distortion to be made cannot be 20% or more. For example, as a means for imparting processing strain to an aluminum alloy material, there is another method of applying tension using a straightening machine such as a roll or tension (tension leveler). It cannot be as large as 20% or more. That is, in order to increase the amount of processing strain in this way, it is difficult to perform bending using a bending mold.
(化学成分組成)
次に、本発明が対象とする6000系アルミニウム合金材の化学成分組成について説明する。本発明が対象とする6000系アルミニウム合金材は、前記した自動車材などとして、優れた成形性やBH(ベークハード)性、強度、溶接性、耐食性などの諸特性が要求される。このような要求を満足するために、6000系アルミニウム合金材の基本組成は、質量% で、Mg:0.2〜2.0%、Si:0.3〜2.0%を含有する6000系アルミニウム合金材が好ましい。なお、本発明での化学成分組成の%表示は、全て質量%の意味である。
(Chemical composition)
Next, the chemical composition of the 6000 series aluminum alloy material targeted by the present invention will be described. The 6000 series aluminum alloy material targeted by the present invention is required to have various properties such as excellent formability, BH (bake hard) properties, strength, weldability, and corrosion resistance as the above-mentioned automobile materials. In order to satisfy these requirements, the basic composition of the 6000 series aluminum alloy material is 6000 series containing Mg: 0.2-2.0% and Si: 0.3-2.0% in mass%. Aluminum alloy material is preferred. In addition, the% display of the chemical component composition in this invention all means the mass%.
また、本発明が対象とする6000系アルミニウム合金材は、その優れたBH性ゆえに室温での時効硬化が問題となり、本発明を必要とする。この点、6000系アルミニウム合金の中でも、室温での時効硬化がより問題となる、Si/Mg比が質量比で1以上の所謂Si過剰型の6000系アルミニウム合金材に適用されて好ましい。このような6000系アルミニウム合金材としては、例えば、自動車材としてのアウタパネル用の板などがあり、組成としては、Mg:0.2〜2.0%、Si:0.3〜2.0%、Mn:0.01〜0.65%、Cu:0.001〜1.0%を含有し、かつSi/Mg比が質量比で1以上であり、残部Alおよび不可避的不純物からなるものが好ましい。   In addition, the 6000 series aluminum alloy material targeted by the present invention has a problem of age hardening at room temperature because of its excellent BH property, and the present invention is required. In this respect, among the 6000 series aluminum alloys, it is preferable to be applied to a so-called Si-excess type 6000 series aluminum alloy material having a Si / Mg ratio of 1 or more by mass ratio, in which age hardening at room temperature becomes more problematic. Examples of such a 6000 series aluminum alloy material include a plate for an outer panel as an automobile material, and the composition is Mg: 0.2 to 2.0%, Si: 0.3 to 2.0%. , Mn: 0.01 to 0.65%, Cu: 0.001 to 1.0%, and the Si / Mg ratio is 1 or more in terms of mass ratio, with the balance being Al and inevitable impurities preferable.
なお、その他の元素は、AA乃至JIS規格などに沿った各不純物レベルの含有量 (許容量) とする。その他の合金元素とは、具体的には、Fe:1.0%以下、Cr:0.3%以下、Zr:0.3%以下、V:0.3%以下、Ti:0.1%以下の内の1 種または2 種以上を選択的に含んでも良い。   For other elements, the content (allowable amount) of each impurity level in accordance with AA to JIS standards. Specifically, the other alloy elements are Fe: 1.0% or less, Cr: 0.3% or less, Zr: 0.3% or less, V: 0.3% or less, Ti: 0.1% One or more of the following may be selectively included.
上記合金元素以外のその他の合金元素やガス成分は不純物である。しかし、リサイクルの観点から、溶解材として、高純度Al地金だけではなく、6000系合金やその他のAl合金スクラップ材、低純度Al地金などを溶解原料として使用して、本発明Al合金を溶製する場合には、これら他の合金元素は必然的に含まれることとなる。したがって、本発明では、目的とする本発明効果を阻害しない範囲で、これら不純物元素が含有されることを許容する。   Other alloy elements and gas components other than the above alloy elements are impurities. However, from the viewpoint of recycling, not only high-purity Al ingots but also 6000 series alloys, other Al alloy scrap materials, low-purity Al ingots, etc. are used as melting raw materials as melting materials. In the case of melting, these other alloy elements are necessarily included. Accordingly, the present invention allows these impurity elements to be contained within a range that does not impair the intended effect of the present invention.
(製造方法)
Al合金材の製造は、形状に応じた常法で可能である。Al合金の溶解、鋳造工程では、本発明成分規格範囲内に溶解調整されたAl合金溶湯を、連続鋳造圧延法、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。次いで、常法により、このAl合金鋳塊に均質化熱処理を施した後、熱間圧延、熱間押出、されて、コイル状、板状、形材、管材などの製品材とするか、更に、必要に応じて中間焼鈍を行なって冷間圧延を行い、コイル状、板状などの製品冷延板に加工する。これら加工後のAl合金材は、調質処理として、必須に溶体化および焼入れ処理で調質されて製品板とされる。用途や必要特性に応じて、更に高温での時効処理や安定化処理などの調質処理を付加して行うことも勿論可能である。
(Production method)
The production of the Al alloy material can be performed by a conventional method according to the shape. In the melting and casting process of the Al alloy, a normal melting and casting method such as a continuous casting and rolling method or a semi-continuous casting method (DC casting method) is appropriately selected for the molten Al alloy melt adjusted within the range of the present invention component. And cast. Then, after subjecting this Al alloy ingot to homogenization heat treatment by a conventional method, it is hot-rolled and hot-extruded to obtain a product material such as a coil shape, a plate shape, a shape material, a pipe material, If necessary, intermediate annealing is performed, cold rolling is performed, and the product is rolled into a product cold-rolled sheet such as a coil or plate. These processed Al alloy materials are tempered by solution treatment and quenching as a tempering treatment, and are used as product plates. Of course, it is possible to add a tempering treatment such as an aging treatment or a stabilization treatment at a higher temperature according to the use and required characteristics.
次に、本発明の実施例を説明する。室温時効した6000系アルミニウム合金板に対して、本発明の曲げ加工方法を施し、後段の曲げ加工であるヘム加工性を評価した。   Next, examples of the present invention will be described. The 6000 series aluminum alloy plate aged at room temperature was subjected to the bending method of the present invention, and the hemming property as a subsequent bending process was evaluated.
表1に示すAA6022規格組成、T4調質材で、板厚1.0mmの供試板を、製造後6カ月間室温時効させた。6カ月間室温時効後の0.2%耐力は圧延方向で145MPa(製造当初から30MPa増加)から、圧延方向を長手方向に長さ200mm×幅30mmの曲げ加工試験片を採取した。   A test plate having a thickness of 1.0 mm with the AA6022 standard composition and T4 tempered material shown in Table 1 was aged at room temperature for 6 months after production. The 0.2% proof stress after aging for 6 months at room temperature was 145 MPa (increased by 30 MPa from the beginning of manufacture) in the rolling direction, and a bending test piece having a length of 200 mm and a width of 30 mm in the rolling direction was collected.
この曲げ加工試験片の周縁部に対して、自動車のアウタパネルのプレス成形を模擬して、10%の歪みをストレッチにて予め加えた。そして、この予め歪みを加えた周縁部に対して、前段の曲げ加工として、表2に示すように、その曲げ外側の材料表面に負荷される加工歪み量(%)を変化させた、金型を用いたダウンフランジ工程により長手方向直角に約90度の曲げ加工を行った。   A 10% strain was preliminarily applied to the peripheral edge portion of the bending test piece by stretching, simulating press molding of an outer panel of an automobile. Then, as shown in Table 2, as a pre-bending process for the peripheral portion to which the strain was applied in advance, as shown in Table 2, the amount of work strain (%) applied to the material surface outside the bend was changed. A bending process of about 90 degrees was performed at a right angle in the longitudinal direction by a down-flange process using the.
ここで、この約90度の曲げ加工後に、曲げ外側の板表面に生じる加工歪み量は、前記したFEM数値解析によって求めた。   Here, after the bending process of about 90 degrees, the amount of processing distortion generated on the surface of the outer plate was determined by the FEM numerical analysis described above.
発明例は、周縁部に、上記前段となる約90度の曲げ加工を施した試験片の周縁部に対して、表2に示すように、昇温速度、加熱温度、保持時間を条件を変化させた熱処理を行った。   As shown in Table 2, the invention example changes the conditions of the heating rate, heating temperature, and holding time with respect to the peripheral part of the test piece subjected to the bending process of about 90 degrees, which is the preceding stage, at the peripheral part as shown in Table 2. Heat treatment was performed.
この熱処理後で、約90度の曲げ加工を施した試験片周縁部に対して、自動車のアウタパネルのヘム加工を模擬して、板厚0.8mmのインナパネルを挟み込み、金型を用いて更に約135度まで曲げるプリヘム加工を経て、金型を用いて更に約180度まで曲げるフラットヘム加工を行った。ここで、上記熱処理後、ヘム加工開始までの時間も、表2に示すように変化させた。   After this heat treatment, the hem processing of the outer panel of the automobile was simulated on the periphery of the test piece that had been bent at about 90 degrees, and an inner panel having a thickness of 0.8 mm was sandwiched between the test panel and the mold. After pre-hem processing that bends to about 135 degrees, flat hem processing was performed to further bend to about 180 degrees using a mold. Here, as shown in Table 2, the time from the heat treatment to the start of hem processing was also changed.
比較のために、加熱処理を行わない、又は表2に示す本発明の範囲外の条件で加熱処理を行った比較例も、同様にヘム加工試験した。   For comparison, a hem processing test was also conducted in the same manner for a comparative example in which heat treatment was not performed or heat treatment was performed under conditions outside the scope of the present invention shown in Table 2.
ヘム加工性は、試験片周縁部の最終の180曲げ部外側 (フラットヘム加工部外周部) の表面状態を目視観察して評価した。評価は、上記曲げ部外側の割れ発生程度を目視で確認し、下記基準に基づいて5段階で評価した。
0:肌荒れ、及び微小な割れが無い。
1:肌荒れが僅かに発生している。
2:肌荒れが発生しているものの割れは無い。
3:微小な割れが発生。
4:大きな割れが発生。
なお、上記のランクの内、0〜2段階がヘム加工性 (実際の自動車アウタパネル用) として合格で、3〜4段階は不合格である。
Hem workability was evaluated by visually observing the surface state of the outer side of the final 180 bent portion (outer portion of the flat hem processed portion) at the periphery of the test piece. The evaluation was performed by visually checking the degree of occurrence of cracks on the outside of the bent portion, and evaluated in five stages based on the following criteria.
0: No rough skin and fine cracks.
1: Rough skin is generated.
2: There is no cracking of the rough skin.
3: Small cracks occurred.
4: Large cracks occurred.
Of the above ranks, 0 to 2 stages are acceptable as hem workability (for an actual automobile outer panel), and 3 to 4 stages are unacceptable.
表2から明らかな通り、発明例1〜10は、本発明要件である、加工歪み量を付加する前段の曲げ加工、続く熱処理を施してフラットヘム加工を行っている。この結果、これら本発明要件のいずれかが外れた上でフラットヘム加工を行っている、比較例11〜15に比して、格段にヘム加工性が向上している。更に、表2から明らかな通り、熱処理がより望ましい条件で行われている、発明例1〜5は、発明例の中でも更に良好なヘム加工性が得られている。これら発明例は、本発明要件を満足すれば、室温時効して成形性が低下した過剰Si型の組成の6000系Al合金板でも、曲げ半径(折り曲げ半径)Rdが2.0 mm 以下のような小さなフラットヘム加工のような厳しい曲げ加工ができることを裏付けている。   As is clear from Table 2, Invention Examples 1 to 10 perform the flat hem processing by applying the preceding bending process for adding the processing strain amount and the subsequent heat treatment, which are the requirements of the present invention. As a result, the hem workability is remarkably improved as compared with Comparative Examples 11 to 15 in which flat hem processing is performed after any of these requirements of the present invention are removed. Further, as is apparent from Table 2, Invention Examples 1 to 5, in which the heat treatment is performed under more desirable conditions, have even better hemmability than the invention examples. If these invention examples satisfy the requirements of the present invention, the bending radius (bending radius) Rd is 2.0 mm or less even with an excess Si type composition 6000 series Al alloy plate that has been aged at room temperature and has reduced formability. This proves that it can be rigorously bent like a small flat hem.
比較例11は本発明に係る熱処理を施していない。比較例12は熱処理時の加熱温度が低すぎる。比較例13は熱処理時の加熱保持時間が短すぎる。比較例14は熱処理時の加熱温度が高すぎる。比較例15は熱処理時の加熱昇温速度が小さすぎる。これら比較例は、本発明要件を満足しなければ、室温時効して成形性が低下した過剰Si型の組成の6000系Al合金板では、曲げ半径が小さなフラットヘム加工のような厳しい曲げ加工ができないことを裏付けている。したがって、これらの結果から、本発明要件の臨界的な意義も裏付けられている。   Comparative Example 11 is not subjected to the heat treatment according to the present invention. In Comparative Example 12, the heating temperature during the heat treatment is too low. In Comparative Example 13, the heat holding time during the heat treatment is too short. In Comparative Example 14, the heating temperature during the heat treatment is too high. In Comparative Example 15, the heating temperature increase rate during the heat treatment is too small. In these comparative examples, if the requirements of the present invention are not satisfied, the 6000 series Al alloy plate having an excessive Si type composition that has been aged at room temperature and has reduced formability, can be subjected to severe bending such as flat hem processing with a small bending radius. I support what I can't do. Therefore, these results also support the critical significance of the requirements of the present invention.
本発明によれば、室温時効して成形性が低下した過剰Si型の組成の6000系Al合金板でも、曲げ半径(折り曲げ半径)Rdが2.0 mm 以下のような小さなフラットヘム加工のような厳しい曲げ加工ができる加工方法を提供できる。この結果、特に、自動車などの輸送機の部材として、6000系Al合金材の適用を拡大できる。   According to the present invention, even a 6000 series Al alloy plate having an excess Si type composition that has been aged at room temperature and has a reduced formability, seems to have a small flat hem processing with a bending radius (bending radius) Rd of 2.0 mm or less. It can provide a processing method that can perform strict bending. As a result, in particular, the application of the 6000 series Al alloy material can be expanded as a member of a transport device such as an automobile.
ヘム加工工程を示す断面図である。It is sectional drawing which shows a hem processing process. 板の曲げ加工時を模式的に示す説明図である。It is explanatory drawing which shows typically the time of bending of a board.
符号の説明Explanation of symbols
1: アウタパネル、1a、1b、1c、1d:アウタパネル周縁部(折り曲げ部)、2:インナパネル、3:ダイス、4:ポンチ、5:板押さえ、6:アウタパネル曲げコーナー部、 1: Outer panel, 1a, 1b, 1c, 1d: Outer panel peripheral edge (bending part), 2: Inner panel, 3: Die, 4: Punch, 5: Plate presser, 6: Outer panel bending corner,

Claims (4)

  1. 6000系アルミニウム合金材を曲げ加工するに際し、曲げ加工されるアルミニウム合金材に、その曲げ外側の材料表面に負荷される加工歪み量が20%以上である曲げ加工を予め施し、このアルミニウム合金材に対して、更に、1℃/分以上の昇温速度で50〜150℃に加熱し、1分を超え、20分以下の範囲で保持する熱処理を行った後に、曲げ加工を行うことを特徴とするアルミニウム合金材の曲げ加工方法。   When bending a 6000 series aluminum alloy material, the aluminum alloy material to be bent is preliminarily subjected to a bending process in which the amount of processing strain applied to the material surface outside the bending is 20% or more. On the other hand, it is further characterized in that it is heated to 50 to 150 ° C. at a temperature rising rate of 1 ° C./min or more, subjected to a heat treatment for holding in the range of more than 1 minute and not more than 20 minutes, and then bending is performed. Bending method of aluminum alloy material.
  2. 前記熱処理後30分以内に前記曲げ加工を行う請求項1に記載のアルミニウム合金材の曲げ加工方法。   The method of bending an aluminum alloy material according to claim 1, wherein the bending is performed within 30 minutes after the heat treatment.
  3. 前記アルミニウム合金材が板であり、前記加工歪み量を生じる条件での曲げ加工が、この板のプレス成形中に施され、前記熱処理後の曲げ加工がヘム加工である請求項1または請求項2に記載のアルミニウム合金材の曲げ加工方法。   3. The aluminum alloy material is a plate, bending under a condition that causes the amount of processing distortion is performed during press forming of the plate, and the bending after the heat treatment is hem processing. The bending method of the aluminum alloy material as described in 2.
  4. 前記アルミニウム合金材がアウタパネルであり、前記加工歪み量を生じる条件での曲げ加工がヘム加工におけるダウンフランジ加工であり、前記熱処理後の曲げ加工がヘム加工におけるプリヘム加工を経た180度曲げ加工である請求項1乃至3のいずれか1項に記載のアルミニウム合金材の曲げ加工方法。   The aluminum alloy material is an outer panel, the bending process under the condition for generating the processing strain is a down flange process in the hem process, and the bending process after the heat treatment is a 180 degree bending process through a pre-hem process in the hem process. The bending method of the aluminum alloy material of any one of Claims 1 thru | or 3.
JP2007088799A 2007-03-29 2007-03-29 Bending method of aluminum alloy material Pending JP2008246508A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2110235A1 (en) * 2008-10-22 2009-10-21 Aleris Aluminum Duffel BVBA Al-Mg-Si alloy rolled sheet product with good hemming
JP2014088077A (en) * 2012-10-30 2014-05-15 Shiroki Corp Door frame structure and door frame production method
CN112122466A (en) * 2020-11-24 2020-12-25 潍坊维润金属科技有限公司 Steel sheet processing punching press flanging machine

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005240083A (en) * 2004-02-25 2005-09-08 Kobe Steel Ltd Method for molding aluminum alloy material

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005240083A (en) * 2004-02-25 2005-09-08 Kobe Steel Ltd Method for molding aluminum alloy material

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2110235A1 (en) * 2008-10-22 2009-10-21 Aleris Aluminum Duffel BVBA Al-Mg-Si alloy rolled sheet product with good hemming
JP2014088077A (en) * 2012-10-30 2014-05-15 Shiroki Corp Door frame structure and door frame production method
CN112122466A (en) * 2020-11-24 2020-12-25 潍坊维润金属科技有限公司 Steel sheet processing punching press flanging machine
CN112122466B (en) * 2020-11-24 2021-04-23 潍坊维润金属科技有限公司 Steel sheet processing punching press flanging machine

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