JP2004323952A - Aluminum alloy sheet for forming, and its production method - Google Patents
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Description
【０００１】
【発明が属する技術分野】
この発明は、自動車ボディシートやそのほか各種自動車部品、各種機械器具、家電製品やその部品等の素材として、成形加工および塗装焼付を施して使用されるＡｌ−Ｍｇ−Ｓｉ系のアルミニウム合金板およびその製造方法に関するものであり、成形性、特にヘム曲げ性が良好であるとともに、塗装焼付後の強度が高く、かつ室温での経時変化が少ない成形加工用アルミニウム合金板およびその製造方法に関するものである。
【０００２】
【従来の技術】
従来自動車のボディシートとしては、主として冷延鋼板を使用することが多かったが、最近では車体軽量化等の観点から、アルミニウム合金圧延板を使用することが多くなっている。ところで自動車のボディシートはプレス加工を施して使用するところから、成形加工性が優れていること、また成形加工時におけるリューダースマークが発生しないことが要求され、また高強度を有することも必須であって、塗装焼付を施して使用するのが通常であるため、塗装焼付後に高強度が得られることが要求される。そしてまた成形性が良好であることが要求されるのはもちろんであるが、自動車用ボディシートとしては、接合のためにヘム曲げ加工を施して使用することが多いところから、成形性のうちでも特にヘム曲げ性が優れていることが強く要求される。
【０００３】
従来このような自動車用ボディシート向けのアルミニウム合金としては、Ａｌ−Ｍｇ系合金のほか、時効性を有するＡｌ−Ｍｇ−Ｓｉ系合金が主として使用されている。この時効性Ａｌ−Ｍｇ−Ｓｉ系合金は、塗装焼付前の成形加工時においては比較的強度が低くて成形性が優れている一方、塗装焼付時の加熱によって時効されて塗装焼付後の強度が高くなる利点を有するほか、リューダースマークが発生しない等の利点を有する。
【０００４】
なお上述のような塗装焼付時における時効硬化を期待した時効性Ａｌ−Ｍｇ−Ｓｉ系合金板の製造方法としては、鋳塊を均質化熱処理した後、熱間圧延および冷間圧延を行なって所定の板厚とし、かつ必要に応じて熱間圧延と冷間圧延との間あるいは冷間圧延の中途において中間焼鈍を行ない、冷間圧延後に溶体化処理を行なって焼入れるのが通常である。
【０００５】
なおまた、ヘム曲げ性向上に関する従来技術としては、加工硬化を制御する特許文献１の技術、晶出物の粒径および間隔を規制することによりヘム曲げ性の向上を図る特許文献２の技術、極限変形能を規制する特許文献３の技術等がある。また本発明者等も特願２００２−１８１７３２、特願２００２−０６６４０５の提案をしている。
【０００６】
【特許文献１】特開２０００−１６０２７４
【特許文献２】特開２０００−１４４２９４
【特許文献３】特開２０００−１０５５７３
【０００７】
【発明が解決しようとする課題】
前述のような自動車用ボディシート向けの時効性Ａｌ−Ｍｇ−Ｓｉ系合金板についての従来の一般的な製造方法により得られた板では、最近の自動車用ボディシートに要求される特性を充分に満足させることは困難であった。
【０００８】
すなわち、最近ではコストの一層の低減や自動車車体の軽量化等のために、自動車用ボディシートについてさらに薄肉化することが強く要求されており、そのため薄肉でも充分な強度が得られるように、一層の高強度化が求められると同時に、成形性、特にヘム曲げ性の改善が強く要求されているが、これらの性能をバランスよく満足させる点について従来の一般的な製造方法によって得られたＡｌ−Ｍｇ−Ｓｉ系合金板では不充分であった。特にヘム曲げ加工は、曲げ内径が１ｍｍ以下の１８０°曲げという過酷な曲げ加工であるため、良好なヘム曲げ性と強度とを両立させることが困難であるという問題があった。
【０００９】
また塗装焼付については、省エネルギおよび生産性の向上、さらには高温に曝されることが好ましくない樹脂等の材料との併用などの点から、従来よりも焼付温度を低温化し、また焼付時間も短時間化する傾向が強まっている。しかしながら従来の一般的な製法により得られた時効性Ａｌ−Ｍｇ−Ｓｉ系合金板の場合、低温・短時間の塗装焼付処理では、塗装焼付時の硬化（焼付硬化）が不足し、塗装焼付後に充分な高強度が得難くなる問題があった。
【００１０】
ここで、従来の一般的な製法により得られた時効性Ａｌ−Ｍｇ−Ｓｉ系合金板では、塗装焼付後に高強度を得るために焼付硬化性を高めようとすれば、素材の延性と曲げ加工性（特にヘム曲げ性）が低下し、また板製造後に室温に放置した場合に自然時効により硬化が生じやすくなり、そのため成形性、特にヘム曲げ性が阻害されがちとなるという問題が生じている。
【００１１】
一方、曲げ加工性、特にヘム曲げ性を従来の材料よりも格段に向上させようとした場合、異方性の大きい材料となりがちであるという問題があった。具体的には、圧延方向と平行な方向の伸びが従来と比べて格段に低下したり、また圧延方向に対し４５°の方向の曲げ性が著しく低下したりする問題があった。
【００１２】
この発明は以上の事情を背景としてなされたもので、良好な成形加工性、特に良好な曲げ加工性を有すると同時に、異方性（ヘム曲げ性の異方性、機械的特性の異方性）も少なく、さらには焼付硬化性が優れていて、塗装焼付時における強度上昇が大きく、しかも板製造後の室温での経時的な変化が少なくて、長期間放置した場合でも自然時効による硬化に起因する成形性の低下も少ない成形加工用アルミニウム合金板およびその製造方法を提供することを目的とするものである。
【００１３】
【課題を解決するための手段】
前述のような課題を解決するべく本発明者等が種々実験・検討を重ねた結果、Ａｌ−Ｍｇ−Ｓｉ系合金の成分組成を適切に調整するばかりでなく、板の結晶方位、特に板厚方向の各部位における結晶方位を適切に制御すると同時に、板の小角粒界の長さの和を適切に規制することによって、曲げ加工性、特にヘム曲げ性を向上させると同時に、曲げ異方性、その他機械的異方性を小さくし得ることを見出した。さらに、板製造プロセスにおける熱間圧延、冷間圧延、熱処理における合金の組織変化を解析して、前述のような良好な特性を示し得る組織を有する成形加工用アルミニウム合金板を得るために必要な製造プロセス条件を見出し、この発明をなすに至ったのである。
【００１４】
具体的には、請求項１の発明の成形加工用アルミニウム合金板は、Ｍｇ０．３〜１．０％、Ｓｉ０．３〜１．５％を含有し、かつＭｎ０．０３〜０．４％、Ｃｒ０．０３〜０．４％、Ｆｅ０．０３〜０．５％、Ｔｉ０．００５〜０．２％、Ｚｎ０．０３〜２．５％のうちから選ばれた１種または２種以上を含有し、さらにＣｕが１％以下に規制され、残部がＡｌおよび不可避的不純物よりなる合金を素材とし、板表面から全板厚の２／５の深さの位置までの領域を板表面側領域とするとともに、板表面から全板厚の２／５の深さの位置よりも板厚方向中央部側の領域を板中央部側領域とし、板表面側領域における平均キューブ方位密度がランダム結晶方位を有する試料の８〜２５０倍の範囲内にあり、かつ板中央部側領域における平均キューブ方位密度がランダム結晶方位を有する試料の２００倍以下であり、しかも板表面側領域の平均キューブ方位密度が板中央部側領域の平均キューブ方位密度よりも高く、さらに板全体の粒界のうち、粒界における結晶回転角が５°以上１５°以下の小角粒界の粒界長さの和が、粒界における結晶回転角が５°以上の全粒界の長さの総和に対して２〜９０％の範囲内となっており、さらに板の０°方向の耳率、９０°方向の耳率がいずれも５％以上であり、導電率が５４％ＩＡＣＳ以下であることを特徴とするものである。
【００１５】
また請求項２の発明の成形加工用アルミニウム合金板の製造方法は、Ｍｇ０．３〜１．０％、Ｓｉ０．３〜１．５％を含有し、かつＭｎ０．０３〜０．４％、Ｃｒ０．０３〜０．４％、Ｆｅ０．０３〜０．５％、Ｔｉ０．００５〜０．２％、Ｚｎ０．０３〜２．５％のうちから選ばれた１種または２種以上を含有し、さらにＣｕが１％以下に規制され、残部がＡｌおよび不可避的不純物よりなるアルミニウム合金鋳塊を熱間圧延するにあたり、
▲１▼熱間圧延途中の板厚２５０〜１００ｍｍの段階における板温度を５００〜３２０℃の範囲内とし、
▲２▼熱間圧延途中の板厚１００〜１５ｍｍの段階における板温度を４５０〜２７０℃の範囲内とし、
▲３▼熱間圧延の上がり板厚を１．５〜８ｍｍとし、
▲４▼熱間圧延上がり温度を１８０〜３５０℃の範囲内とし、
▲５▼熱間圧延中における板厚２５０ｍｍ以降の段階の各圧延パスにおける歪み速度を０．２／秒〜３５０／秒の範囲内とし、
▲６▼熱間圧延中における板厚２５０ｍｍ以降の段階の各圧延パス間の滞留時間を１０分未満とし、
▲７▼熱間圧延中の板厚５０ｍｍ以降の段階における圧延ロールと板との接触部分のロール表面の平均温度を３５０℃以下とし、
以上▲１▼〜▲７▼が満たされるように制御して熱間圧延を終了させ、さらに中間焼鈍を施すことなく圧延率３０％以上で冷間圧延を施して製品板厚とした後、その圧延板に対し、４８０℃以上の温度での５分以内の溶体化処理を行なってから１００℃／ｍｉｎ以上の平均冷却速度で５０℃以上１５０℃未満の温度域まで冷却し、続いてその温度域内において２時間以上で保持もしくは徐冷する安定化処理を行なうことを特徴とするものである。
【００１６】
またさらに請求項３の発明の成形加工用アルミニウム合金板の製造方法は、請求項２に記載の成形加工用アルミニウム合金板の製造方法において、前記安定化処理の後、さらに１００℃／ｍｉｎ以上の加熱速度で１７０〜２８０℃の範囲内の温度に加熱してその範囲内の温度で５分以上保持した後、１００℃／ｍｉｎ以上の冷却速度で冷却する最終熱処理を施すことを特徴とするものである。
【００１７】
【発明の実施の形態】
先ずこの発明の成形加工用アルミニウム合金板における成分組成の限定理由について説明する。
【００１８】
Ｍｇ：
Ｍｇはこの発明で対象としている系の合金で基本となる合金元素であって、Ｓｉと共同して強度向上に寄与する。Ｍｇ量が０．３％未満では塗装焼付時に析出硬化によって強度向上に寄与するＧ．Ｐ．ゾーンの生成量が少なくなるため、充分な強度向上が得られず、一方１．０％を越えれば、粗大なＭｇ−Ｓｉ系の金属間化合物が生成され、成形性、特に曲げ加工性が低下するから、Ｍｇ量は０．３〜１．０％の範囲内とした。
【００１９】
Ｓｉ：
Ｓｉもこの発明の系の合金で基本となる合金元素であって、Ｍｇと共同して強度向上に寄与する。またＳｉは、鋳造時に金属Ｓｉの晶出物として生成され、その金属Ｓｉ粒子の周囲が加工によって変形されて、溶体化処理の際に再結晶核の生成サイトとなるため、再結晶組織の微細化にも寄与する。Ｓｉ量が０．３％未満では上記の効果が充分に得られず、一方１．５％を越えれば粗大なＳｉ粒子や粗大なＭｇ−Ｓｉ系の金属間化合物が生じて、曲げ加工性の低下を招く。したがってＳｉ量は０．３〜１．５％の範囲内とした。
【００２０】
Ｍｎ、Ｃｒ、Ｆｅ、Ｔｉ、Ｚｎ：
これらの元素は、強度向上や結晶粒微細化、あるいは時効性の向上や表面処理性の向上に有効であり、いずれか１種または２種以上を添加する。これらのうちＭｎ、Ｃｒは強度向上と結晶粒の微細化および組織の安定化に効果がある元素であり、いずれも含有量が０．０３％未満では上記の効果が充分に得られず、一方Ｍｎ、Ｃｒの含有量がそれぞれ０．４％を越えれば、上記の効果が飽和するばかりでなく、多数の金属間化合物が生成されて成形性、特にヘム曲げ性に悪影響を及ぼすおそれがあり、したがってＭｎ、Ｃｒはいずれも０．０３〜０．４％の範囲内とした。またＦｅも強度向上と結晶粒微細化に有効な元素であり、その含有量が０．０３％未満では充分な効果が得られず、一方０．５％を越えれば成形性が低下するおそれがあり、したがってＦｅ量は０．０３〜０．５％の範囲内とした。さらにＴｉも強度向上と鋳塊組織の微細化に有効な元素であり、その含有量が０．００５％未満では充分な効果が得られず、一方０．２％を越えればＴｉ添加の効果が飽和するばかりでなく、粗大な晶出物が生じるおそれがあるから、Ｔｉ量は０．００５〜０．２％の範囲内とした。またＺｎは時効性向上を通じて強度向上に寄与するとともに表面処理性の向上に有効な元素であり、Ｚｎの添加量が０．０３％未満では上記の効果が充分に得られず、一方２．５％を越えれば成形性が低下するから、Ｚｎ量は０．０３〜２．５％の範囲内とした。
【００２１】
Ｃｕ：
Ｃｕは強度向上および成形性向上のために添加されることがある元素であるが、その量が１．０％を越えれば耐食性（耐粒界腐食性、耐糸錆性）が劣化するから、Ｃｕの含有量は１．０％以下に規制することとした。なお特に耐食性を重視する場合は、Ｃｕ量は０．０５％以下に規制することが望ましい。
【００２２】
以上の各元素のほかは、基本的にはＡｌおよび不可避的不純物とすれば良い。
【００２３】
なお上記のＭｎ、Ｃｒ、Ｆｅ、Ｔｉ、Ｚｎの含有量範囲は、それぞれ積極的に添加する場合の範囲として示したものであり、いずれも下限値より少ない量を不純物として含有する場合を排除するものではない。特に０．０３％未満のＦｅは、通常のアルミ地金を用いれば不可避的に含有されるのが通常である。
【００２４】
また時効性Ａｌ−Ｍｇ−Ｓｉ系合金においては、高温時効促進元素あるいは室温時効抑制元素であるＡｇ、Ｉｎ、Ｃｄ、Ｂｅ、あるいはＳｎを微量添加することがあるが、この発明の場合も微量添加であればこれらの元素の添加も許容され、それぞれ０．３％以下であれば特に所期の目的を損なうことはない。
【００２５】
なおまた、一般のＡｌ合金においては、結晶粒微細化のために前述のＴｉと同時にＢを添加することもあり、この発明の場合もＴｉとともに５００ｐｐｍ以下のＢを添加することは許容される。
【００２６】
さらにこの発明の成形加工用アルミニウム合金板において、良好な曲げ加工性、特に良好なヘム曲げ性を得ると同時に異方性の増大を避けるためには、合金の成分組成を前述のように調整するばかりではなく、板の金属組織、特に結晶方位密度を、板厚方向の各領域に応じて適切に制御する必要がある。すなわち、板の表面から板厚方向に全板厚の２／５に相当する深さの位置までの領域を板表面側領域とし、かつそれよりも板厚方向内側の領域（板の表面から板厚方向に全板厚の２／５の深さに相当する位置よりも板厚方向中央部寄りの領域）を板中央部側領域とすれば、
▲１▼板表面側領域における平均キューブ方位密度がランダム結晶方位を有する試料の８〜２５０倍の範囲内にあること、
▲２▼板中央部側領域における平均キューブ方位密度がランダム結晶方位を有する試料の２００倍以下であること、
▲３▼板表面側領域における平均キューブ方位密度が板中央部側領域における平均キューブ方位密度よりも高いこと、
以上▲１▼〜▲３▼の条件が満たされる必要がある。このように結晶方位密度を板厚方向の各領域に応じて制御することとした理由は次の通りである。
【００２７】
先ず▲１▼の条件に関して、板表面側領域でキューブ方位の平均密度がランダム結晶方位を有する試料のものに比べて８倍未満の場合、ヘム曲げ時に曲げ部位にせん断帯などの滑り線が発達し、曲げ歪みが集中しやすく、このように歪みが集中した箇所に割れが発生するおそれがある。またこの場合、圧延方向と平行な方向、あるいは圧延方向に対して垂直な方向に比べて、圧延方向に対して４５°方向の曲げ性の低下が大きく、曲げ異方性が強くなってしまう。一方、板表面側領域でキューブ方位の平均密度がランダム結晶方位を有する試料の２５０倍を越えれば、結晶方位による曲げ性向上効果が飽和するばかりでなく、加工時の肌荒れ欠陥が発生するおそれがある。そのため、前記▲１▼のように板表面側領域におけるキューブ方位の平均密度をランダム結晶方位を有する試料の８倍以上２５０倍以下と規定した。
【００２８】
次に▲２▼の条件に関して、板中央部側領域でキューブ方位の平均密度がランダム方位を有する試料の２００倍を超えれば、機械的性能の異方性が顕著になりやすく、特に圧延方向と平行な方向での引張試験片の伸びが著しく低下する。そこで前記▲２▼のように板中央部側領域のキューブ方位の平均密度をランダム方位を有する試料の２００倍以下と規定した。
【００２９】
さらに▲３▼の条件に関して、板中央部側領域におけるキューブ方位の平均密度が板表面側領域におけるキューブ方位の平均密度よりも高くなれば、機械的性能の異方性が強くなるから、前記▲２▼のように、板表面側領域の平均キューブ方位密度を板中央部側領域の平均キューブ方位密度より高くすることを規定した。
【００３０】
ここで、上記▲１▼〜▲３▼の条件は、板厚方向での各領域のキューブ方位密度を規定しているが、キューブ方位以外の結晶方位の方位密度も曲げ性に対してある程度は影響を与える。しかしながらキューブ方位以外の結晶方位の方位密度をすべて細かく規定することは現実には極めて困難である。
【００３１】
一方、板のカッピング試験で絞ったカップの耳率によれば、材料の結晶方位をマクロ的に評価することができる。そこでこの発明では、キューブ方位以外の結晶方位の方位密度の影響を、０°耳率、９０°耳率で規定している。すなわち、圧延方向を基準にカップの０°耳率、９０°耳率が５％未満では、前記▲１▼〜▲３▼のキューブ方位密度の条件を満足しても、良好な曲げ性が得られないおそれがあるから、圧延方向に対し０°、９０°の耳率を５％以上に制御することとした。
【００３２】
さらにこの発明では、結晶組織における小角粒界の長さの和、すなわち回転角が５〜１５°の範囲内にある粒界の長さの和が、回転角５°以上の全ての粒界の長さの総和に対し５〜９０％の範囲内にある必要がある。すなわち、５°以上１５°以下の小角粒界の長さの和が、５°以上の全ての粒界長さの総和に対して一定の範囲内であることによって、粒界に沿うような曲げ割れを緩和する効果が得られる。そしてこの割合が２％未満では、良好な曲げ性が得られなくなるおそれがあり、一方９０％を越えれば、成形加工時に肌荒れが生じて、板表面品質の低下を招くおそれがある。そこででこの発明では、良好な曲げ性を得ると同時に良好な板表面品質を得るため、上述のように小角粒界の割合を規定した。
【００３３】
また以上のほか、この発明では板の導電率を５４％ＩＡＣＳ以下と規定している。すなわち、一般に導電率は固溶元素の固溶量の指標となるが、導電率が５４％ＩＡＣＳを越える場合、固溶しているＭｇとＳｉの量が少ないため、時効析出硬化量が充分に得られず、塗装焼付後に充分な高強度が得難くなる。そこで塗装焼付後に高強度を得るためには、板の導電率が５４％ＩＡＣＳ以下である必要がある。なお導電率の下限は特に規制しないが、通常この系の合金は、導電率を４０％ＩＡＣＳ以下としても、塗装焼付硬化性の効果が飽和し、また工業的にこれを実現することは困難である。
【００３４】
次にこの発明の成形加工用アルミニウム合金板の製造方法について説明する。
【００３５】
先ず前述のような成分組成の合金を常法に従って溶製し、ＤＣ鋳造法などの通常の鋳造法によって鋳造する。得られた鋳塊について、通常は均質化処理を施してから熱間圧延を行なう。この熱間圧延は、最終製品板の結晶方位に大きな影響を与える重要な工程であり、前述のような結晶方位条件を満たした最終製品板を得るためには、熱間圧延の条件、特に熱間圧延中の各段階での条件を次の▲１▼〜▲７▼によって規制する必要がある。
▲１▼ 熱間圧延過程中の板厚２５０〜１００ｍｍの段階における板温度を５００〜３２０℃の範囲内とすること。
▲２▼ 熱間圧延過程中の板厚１００〜１５ｍｍの段階における板温度を４５０〜２７０℃の範囲内とすること。
▲３▼ 熱間圧延の上がり板厚を１．５〜８ｍｍとすること。
▲４▼ 熱間圧延上がり温度を１８０〜３５０℃の範囲内とすること。
▲５▼ 熱間圧延過程中の板厚２５０ｍｍ以降の段階の各圧延パスにおける歪み速度を０．２／秒〜３５０／秒の範囲内とすること。
▲６▼ 熱間圧延過程中の板厚２５０ｍｍ以降の段階の各圧延パス間の滞留時間を１０分未満とすること。
▲７▼ 熱間圧延過程中の板厚５０ｍｍ以降の段階における圧延ロールと板との接触部分のロール表面の平均温度を３５０℃以下とすること。
【００３６】
すなわち、熱間圧延中においては、材料は常に回復・再結晶が繰返されるため、各板厚段階において、温度、各圧延パスの歪み速度、各圧延パス間の滞留時間、さらに圧延ロールの表面温度を、上記の▲１▼〜▲７▼のように厳密に制御することが、結晶方位の制御にとって極めて重要である。そして上記の▲１▼〜▲７▼の条件を外せば、最終製品板として既に述べたような結晶方位密度条件を満たしたものが得られないおそれがある。またここで、板厚が１００〜１５ｍｍの段階の板温度を２７０℃以上とすること、また熱延上がりの温度を１８０℃以上とすること、また板厚２５０ｍｍ以下の段階での各圧延パスにおける歪み速度を３５０／秒以下とすること、さらに板厚５０ｍｍ以降の段階でのロール表面の平均温度を３５０℃以下に保つことは、いずれも結晶方位の制御のみならず、板の表面品質の確保のためにも必要な条件である。なお圧延ロールと板との接触部分におけるロール表面の平均温度は、ロールと圧延板との接触部分における長さ方向の両端と中央の３個所について、放射温度計によって温度を測定し、その平均値をロール表面温度とする。またその平均温度を３５０℃以下に規制することは、冷却用クーラント噴射の制御などによって可能である。
【００３７】
上述のように熱間圧延条件を厳密に規制して熱間圧延を終了させた後には、中間焼鈍を行なわずに直接圧延率３０％以上で冷間圧延を施して所要の板厚（製品板厚）とする。この条件が満たされなければ、既に述べたような結晶方位密度条件を有する製品板が得られない。またここで、冷間圧延率を３０％以上にすることによって、材料に高い歪みエネルギーが蓄積され、熱間圧延後の溶体化処理−焼入れ時に形成された結晶粒が細かくなって、成形加工後に良好な表面外観品質を得ることが可能となる。冷間圧延率が３０％未満では、成形時に肌荒れ等の表面欠陥が発生するおそれがある。
【００３８】
上述のようにして所要の製品板厚とした後には、４８０℃以上の温度で５分以内の溶体化処理を行なう。この溶体化処理は、Ｍｇ２Ｓｉ、単体Ｓｉ等をマトリックスに固溶させ、これにより焼付硬化性を付与して塗装焼付後の強度向上を図るために重要な工程である。この工程は、Ｍｇ２Ｓｉ、単体Ｓｉ粒子等の固溶により第二相粒子の分布密度を低下させて、延性と曲げ性を向上させるためにも寄与し、さらには再結晶により全般的に良好な成形性を得るためにも必要な工程である。
【００３９】
溶体化処理温度が４８０℃未満の場合、室温での経時変化の抑制に対しては有利と思われるが、Ｍｇ２Ｓｉ、Ｓｉなどの固溶量が少なくなって、充分な焼付硬化性が得られないばかりではなく、延性と曲げ性も著しく悪化するから、溶体化処理温度の下限は４８０℃とした。一方溶体化処理温度の上限は特に規定しないが、共晶融解の発生のおそれや再結晶粒粗大化等を考慮して、通常は５８０℃以下とすることが望ましい。また溶体化処理の時間が５分を越えれば溶体化効果が飽和し、経済性を損なうばかりではなく、結晶粒の粗大化のおそれもあるから、溶体化処理の時間は５分以内とした。
【００４０】
溶体化処理後には、１００℃／ｍｉｎ以上の冷却速度で、５０〜１５０℃の温度域まで冷却（焼入れ）する。ここで、溶体化処理後の冷却速度が１００℃／ｍｉｎ未満では、冷却中にＭｇ２Ｓｉあるいは単体Ｓｉが粒界に多量に析出してしまい、成形性、特にヘム曲げ性が低下すると同時に、焼付硬化性が低下して塗装焼付時の充分な強度向上が望めなくなる。
【００４１】
上述のように４８０℃以上の温度での溶体化処理を行なって１００℃／ｍｉｎ以上の冷却速度で５０〜１５０℃未満の温度域内で冷却（焼入れ）した後には、５０℃未満の温度域まで温度降下しないうちに、この温度範囲内（５０〜１５０℃未満）で、２時間以上保持あるいはこの温度範囲で２時間以上冷却（徐冷）する安定化処理を行なう。
【００４２】
このように溶体化処理して５０〜１５０℃未満に焼入れ後、５０℃未満の温度域まで冷却することなくそのまま５０〜１５０℃未満の温度で安定化処理を行なう理由は次の通りである。すなわち、溶体化処理後、特に１００℃／ｍｉｎ以上の平均冷却速度で５０℃未満の室温に冷却した場合には、室温クラスターが生成される。この室温クラスターは強度に寄与するＧ．Ｐ．ゾーンに移行しにくいため、塗装焼付硬化性に不利となる。一方、溶体化処理後に１５０℃以上の温度範囲に冷却してそのまま保持した場合には、Ｇ．Ｐ．ゾーンあるいは安定相が生成され、成形前の素材強度が高くなり過ぎて、ヘム曲げ性とその他の成形性が劣化する。したがってヘム曲げ性、成形性と塗装焼付硬化性とのバランスの観点から、溶体化処理−焼入れ−安定化処理の条件を上述のように定めた。
【００４３】
前述のように安定化処理を行なった後には、これをそのまま製品板として、自動車ボディーシート等のための成形加工に供しても良いが、塗装焼付硬化性とヘム曲げ性をさらに向上させるためには、さらに最終熱処理を行なっても良い。この最終熱処理は、１７０〜２８０℃の温度範囲内に１００℃以上の加熱速度で加熱して保持し、１００℃／ｍｉｎ以上の冷却速度で冷却する条件とする必要がある。
【００４４】
最終熱処理の加熱温度が１７０℃未満では、上述のような最終熱処理の効果が得られず、一方２８０℃を越えれば、室温経時変化が生じ、プレス成形性が劣化する。また最終熱処理の加熱時間が５分を越えれば、最終熱処理の効果が飽和するばかりではなく、場合によっては長時間の時効によって成形前の素材強度が高くなり過ぎて、成形性が劣化する。さらに１７０〜２８０℃の温度への加熱速度が１００℃／ｍｉｎ未満では、時効が進んで成形性が劣化し、一方加熱後の冷却速度が１００℃／ｍｉｎ未満でも、時効が進んで粒界析出が生じ、成形性、特にヘム曲げ性が低下する。したがって最終熱処理の条件は上述の範囲内とした。
【００４５】
なお安定化処理後に最終熱処理を行なう場合における安定化処理と最終熱処理との間の条件については特に規制しないが、安定化処理後は最終熱処理まで材料を室温に放置するのが通常である。そしてその場合の室温放置時間については、材料の室温経時変化などの要素を考慮して、１ケ月以内とすることが好ましい。
【００４６】
以上のように、熱間圧延の条件を厳密に規制し、さらに冷間圧延から溶体化処理−冷却−安定化処理の条件、さらには最終熱処理の条件を規制することによって、既に述べたような結晶方位密度条件や耳率条件、導電率条件を満たし、成形性、特にヘム曲げ性が優れると同時に、材料の異方性が小さく、かつ塗装焼付硬化性が良好でしかも室温時効による経時変化が生じにくい時効性Ａｌ−Ｍｇ−Ｓｉ系アルミニウム合金板を得ることができる。
【００４７】
【実施例】
表１に示すこの発明成分組成範囲内の合金記号Ａ１〜Ａ５の合金、およびこの発明の成分組成範囲外の合金記号Ｂ１の合金について、それぞれ常法に従ってＤＣ鋳造法により鋳造し、得られた鋳塊に５３０℃×２時間の均質化処理を施した後、冷却して面削し、再び５３０℃の温度に加熱して熱間圧延を開始した。熱間圧延は、その中途の板厚２５０ｍｍの段階から上りまでの条件を種々変化させて実施した。これらの詳細な熱間圧延条件を表２〜表４に示す。得られた熱間圧延板に対して冷間圧延を施して、最終的に厚さ１ｍｍの圧延板とした。なお製造番号５については、熱間圧延板を２ｍｍ厚まで冷間圧延した段階で中間焼鈍を施し、その後最終冷間圧延によって１ｍｍ厚とした。得られた各冷間圧延板に対し、種々の溶体化処理を行なってから、１００℃／ｍｉｎ以上の冷却速度で所定の温度域まで冷却（焼入れ）して、引続き種々の安定化処理を行なった。また一部のものについては、安定化処理後、１００℃／ｍｉｎ以上の加熱速度、冷却速度で最終熱処理を行なった。熱間圧延後の具体的なプロセス条件を表５に示す。
【００４８】
以上のようにして得られた各板について、その板厚方向各領域における平均キューブ方位密度を調べるとともに、５〜１５°の範囲内の小角結晶粒界の比率、耳率、導電率を測定した。これらの測定結果を表６に示す。なおこれらの測定条件は次の通りである。
【００４９】
各領域の平均キューブ方位密度の測定：
厚さ１ｍｍの板について、１０％ＮａＯＨ水溶液で表面から板厚中央まで５０μｍずつエッチングしたものを測定サンプルとした。そして板表面側領域（板表面から板厚２／５の深さの位置までの領域）の平均キューブ方位密度は、表面から板厚方向にそれぞれ５０μｍ、１００μｍ、１５０μｍ、２００μｍ、２５０μｍ、３００μｍ、３５０μｍ、４００μｍの各位置でそれぞれ測定したキューブ方位密度の平均値で求めた。また板中央部側領域（表面から板厚２／５の深さの位置よりも内側の領域）の平均キューブ方位密度は、表面から板厚方向にそれぞれ４５０μｍと５００μｍの位置で測定したキューブ方位密度の平均値で求めた。またここで測定装置としては、リガク（株）のガイガーフレックスＲＡＤ−ＲＢなるＸ線回折装置を用い、Ｘ線回折のシェルツ反射法により、｛２００｝、｛２２０｝、｛１１１｝の不完全極点図を測定し、これらを元に三次元結晶方位解析（ＯＤＦ）を行なって調べた。またこれらの解析においては、アルミニウム粉末から作られたランダム結晶方位を有する試料を測定して得たデータを｛２００｝、｛２２０｝、｛１１１｝極点図の解析の際に使う規格化ファイルとし、これによりランダム方位を有する試料に対する倍数としてキューブ方位密度を求めた。なおこの発明においては、結晶方位密度は全て三次元結晶方位解析（ＯＤＦ）に基づくものである。なおまた、一般にキューブ方位は、｛１００｝＜００１＞が理想方位であるが、工業用材料のキューブ方位としては、上記の理想方位を中心に１５°までずれる結晶方位も含ませるの通常であり、そこでこの発明でも理想方位を中心に１５°の範囲内の結晶方位も含ませている。
【００５０】
小角粒界の比率：
粒界回転角５°以上１５°以下の小角粒界の長さの和と粒界回転角５°以上の全ての粒界長さの総和との比率を次のように測定した。すなわち、テクセムラボラトリーズ社製のＯＩＭ装置（ＥＢＳＰ法）を用いて測定された結晶方位のデータをもとに解析して、ミスオリエンテーション・アングル（ｍｉｓｏｒｉｅｎｔａｔｉｏｎ ａｎｇｌｅ）とその数の割合（ｎｕｍｂｅｒ ｆｒａｃｔｉｏｎ）によって調べた。なお測定エリアは、圧延方向と平行な断面において板表層から板厚中央部をカバーする幅４００μｍ、縦５００μｍの領域とした。
【００５１】
耳率：
板に潤滑油を塗布した後、ポンチ径φ３２ｍｍ、ブランク径φ６２ｍｍ、しわ押さえ２０ｋｇの条件でカップに絞り、そのカップの耳率を調べた。なおここで耳率の方向は、圧延方向を基準にした角度を示す。
【００５２】
導電率（％ＩＡＣＳ）：
渦電流式導電率測定装置を用いて銅、黄銅を基準試料として測定を行なった。
【００５３】
さらに前述のように得られた各板について、板製造後室温に１ケ月間放置し、各板について、それぞれ２％ストレッチ後、１７０℃×２０分の塗装焼付処理を施した。塗装焼付前の各板について引張試験を行なって機械的特性（耐力、伸び）を調べるとともにヘム曲げ性を調べ、さらに塗装焼付後の各板についても引張試験を行なってその機械的特性（耐力）を調べた。その結果を表７に示す。これらの試験条件、評価方法は次の通りである。
【００５４】
引張試験：
材料の圧延方向に対して０°、４５°、９０°の三方向でＪＩＳ Ｚ２２０１のＪＩＳ５号引張試験片を採取して、ＪＩＳ Ｚ２２４１に準拠して引張試験を行なった。
【００５５】
ヘム曲げ試験：
材料の圧延方向に対して０°、４５°、９０°の三方向に曲げ試験片を採取し、１５％ストレッチして、突き曲げを行ない、突き曲げ後、中板なしで１８０°に密着曲げを行なった。評価としては、目視で割れが認められなかった場合を合格（○印）とし、目視で割れが認められた場合を不合格（×印）とした。
【００５６】
【表１】
【表２】
【表３】
【表４】
【表５】
【表６】
【表７】
表１〜表７において、製造番号１、２は、合金の成分組成がこの発明で規定する範囲内でかつ製造条件もこの発明で規定する条件を満たしたものであるが、これらの場合は、ヘム曲げ性が優れ、かつ塗装焼付前の伸び異方性、曲げ異方性も小さく、さらには焼付硬化性が高く、塗装焼付時に充分な焼付硬化性を示した。
【００６４】
一方製造番号３〜５は、いずれも合金の成分組成はこの発明で規定する範囲内であるが、製造条件がこの発明で規定する条件を満たさなかったものであり、また製造番号６は、製造条件はこの発明で規定する範囲内であるが、合金の成分組成がこの発明で規定する範囲を外れた比較例である。
【００６５】
これらの比較例のうち、製造番号３は、０°、９０°耳率が低くて、導電率も高く、その結果曲げ異方性が強く、塗装焼付後の強度も充分に得られなかった。また製造番号４は、板中央部側領域の平均キューブ方位密度が高過ぎて、伸びと曲げ異方性が強く、塗装焼付後の強度も充分に得られなかった。さらに製造番号５は、異方性は小さいが、ヘム曲げ性自体が劣っており、また塗装焼付け後の強度も充分に得られなかった。そしてまた製造番号６は、塗装焼付後の強度が高くかつ伸びと曲げの異方性も小さいが、ヘム曲げ性自体が劣っていた。
【００６６】
【発明の効果】
この発明によれば、成形性、特にヘム曲げ性が優れていると同時に、ヘム曲げ性の異方性や機械的性能の異方性等の材料異方性が小さく、しかも塗装焼付硬化性が良好で塗装焼付後の強度が高く、さらに室温での経時変化も少ない成形加工用アルミニウム合金板を得ることができ、したがって自動車用ボディシートなど、成形加工特にヘム曲げ加工と塗装焼付を施して使用されるアルミニウム合金板に最適である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an Al-Mg-Si-based aluminum alloy sheet used as a material for an automobile body sheet and other various automobile parts, various machine tools, home electric appliances and parts thereof, which is used after being subjected to molding and baking. The present invention relates to a manufacturing method, an aluminum alloy sheet for forming which has good formability, particularly good hem bending property, high strength after baking, and little change with time at room temperature, and a method for manufacturing the same. .
[0002]
[Prior art]
Conventionally, cold rolled steel sheets have been mainly used as body sheets for automobiles, but recently, rolled aluminum alloy sheets have been increasingly used from the viewpoint of reducing the weight of a vehicle body. By the way, since the body sheet of an automobile is used after being subjected to press working, it is required that the formability is excellent and that no Rudersmark is generated during the forming, and it is also essential that it has high strength. Therefore, since it is normal to use after baking, it is required that high strength be obtained after baking. Of course, good formability is also required, but as body sheets for automobiles are often used after being subjected to hem bending for joining, In particular, it is strongly required that the hem bendability is excellent.
[0003]
Conventionally, as such aluminum alloys for body sheets for automobiles, Al-Mg-Si alloys having aging properties have been mainly used in addition to Al-Mg alloys. This aging Al-Mg-Si based alloy has relatively low strength and excellent formability during molding before baking, while aging by heating during baking causes the strength after baking to be low. In addition to the advantage of increasing the height, there are advantages such as that no Rudersmark is generated.
[0004]
In addition, as a method of manufacturing an aging Al-Mg-Si based alloy sheet which is expected to undergo age hardening at the time of coating baking as described above, after a homogenizing heat treatment of an ingot, hot rolling and cold rolling are performed. Usually, intermediate annealing is performed between hot rolling and cold rolling or during cold rolling as needed, and a solution treatment is performed after cold rolling to quench.
[0005]
In addition, as a conventional technology relating to the improvement of the hem bendability, a technology of Patent Document 1 for controlling work hardening, a technology of Patent Document 2 for improving hem bendability by regulating the particle size and spacing of crystallized substances, There is a technique disclosed in Patent Document 3 for regulating the ultimate deformability. The present inventors have also proposed Japanese Patent Application Nos. 2002-181732 and 2002-066405.
[0006]
[Patent Document 1] JP-A-2000-160274
[Patent Document 2] JP-A-2000-144294
[Patent Document 3] JP-A-2000-105573
[0007]
[Problems to be solved by the invention]
The plate obtained by the conventional general production method for the aging Al-Mg-Si alloy sheet for the automobile body sheet as described above sufficiently satisfies the characteristics required for the recent automobile body sheet. It was difficult to satisfy.
[0008]
That is, recently, in order to further reduce costs and reduce the weight of an automobile body, it has been strongly required to further reduce the thickness of an automobile body sheet. In addition to the demand for high strength, improvement in formability, particularly in hem bending property, is strongly demanded. However, in terms of satisfying these performances in a well-balanced manner, Al- Mg-Si alloy plates were insufficient. In particular, hem bending is a severe bending process in which the bending inner diameter is 180 ° or less with a bending inner diameter of 1 mm or less, and thus has a problem that it is difficult to achieve both good hem bending properties and strength.
[0009]
Regarding paint baking, the baking temperature has been lowered and the baking time has been reduced from the viewpoint of saving energy and improving productivity, and further using together with materials such as resins that are not preferably exposed to high temperatures. The tendency to shorten the time is increasing. However, in the case of the aging Al-Mg-Si alloy plate obtained by the conventional general manufacturing method, the curing at the time of low-temperature and short-time coating baking (baking hardening) is insufficient. There was a problem that it was difficult to obtain a sufficiently high strength.
[0010]
Here, in the case of an aging Al-Mg-Si based alloy plate obtained by a conventional general manufacturing method, if the baking hardenability is to be increased to obtain high strength after coating baking, the ductility and bending of the material are required. Properties (especially hem bendability) are reduced, and when left at room temperature after the production of the board, the hardening is likely to occur due to natural aging, which causes a problem that moldability, especially hem bendability tends to be inhibited. .
[0011]
On the other hand, when the bending workability, particularly the hem bending property, is to be significantly improved as compared with the conventional material, there is a problem that the material tends to have a large anisotropy. Specifically, there has been a problem that the elongation in a direction parallel to the rolling direction is significantly reduced as compared with the related art, and the bendability in a direction at 45 ° to the rolling direction is significantly reduced.
[0012]
The present invention has been made in view of the above circumstances, and has good forming workability, particularly good bending workability, and anisotropy (hemotropic bending anisotropy, mechanical property anisotropy). ), Excellent bake hardenability, great increase in strength at the time of paint bake, little change over time at room temperature after plate manufacture, and hardening by natural aging even if left for a long time It is an object of the present invention to provide an aluminum alloy sheet for forming which causes less decrease in formability and a method for producing the same.
[0013]
[Means for Solving the Problems]
As a result of various experiments and studies conducted by the present inventors in order to solve the above-described problems, not only is the component composition of the Al-Mg-Si alloy properly adjusted, but also the crystal orientation of the plate, particularly the plate thickness. In addition to appropriately controlling the crystal orientation at each part in the direction and appropriately regulating the sum of the lengths of the small-angle grain boundaries of the plate, the bendability, especially the hem bendability, is improved, and at the same time, the bending anisotropy is improved. , And other mechanical anisotropy can be reduced. Further, the hot rolling in the sheet manufacturing process, cold rolling, by analyzing the structural change of the alloy in the heat treatment, it is necessary to obtain a forming aluminum alloy sheet having a structure that can exhibit good properties as described above. They found the manufacturing process conditions and came to the present invention.
[0014]
Specifically, the aluminum alloy sheet for forming according to the first aspect of the present invention contains 0.3 to 1.0% of Mg and 0.3 to 1.5% of Si, and 0.03 to 0.4% of Mn. It contains one or more selected from Cr 0.03 to 0.4%, Fe 0.03 to 0.5%, Ti 0.005 to 0.2%, and Zn 0.03 to 2.5%. Further, Cu is regulated to 1% or less, and the remainder is made of an alloy composed of Al and inevitable impurities, and a region from the plate surface to a position at a depth of 2/5 of the total plate thickness is defined as a plate surface side region. At the same time, a region closer to the center in the thickness direction than a position at a depth of 2/5 of the total thickness from the surface of the plate is defined as a plate central portion side region, and the average cube orientation density in the region on the plate surface side has a random crystal orientation. Average cue in the range of 8-250 times of the sample and in the central area of the plate Orientation density is 200 times or less of the sample having a random crystal orientation, and the average cube orientation density of the plate surface side region is higher than the average cube orientation density of the plate center region, and among the grain boundaries of the entire plate, The sum of the grain boundary lengths of the small-angle grain boundaries having a crystal rotation angle of 5 ° or more and 15 ° or less at the grain boundaries is 2 to the sum of the lengths of all the grain boundaries having a crystal rotation angle of 5 ° or more at the grain boundaries. 90% range, and furthermore, both the 0 ° direction ear ratio and the 90 ° direction ear ratio of the plate are 5% or more, and the electrical conductivity is 54% IACS or less. It is.
[0015]
The method for producing an aluminum alloy sheet for forming according to the second aspect of the present invention comprises Mg 0.3 to 1.0%, Si 0.3 to 1.5%, Mn 0.03 to 0.4%, Cr 0 0.03 to 0.4%, Fe 0.03 to 0.5%, Ti 0.005 to 0.2%, Zn 0.03 to 2.5%. Further, in hot rolling an aluminum alloy ingot in which Cu is regulated to 1% or less and the balance is Al and inevitable impurities,
{Circle around (1)} The sheet temperature at the stage of a sheet thickness of 250 to 100 mm during hot rolling is set to a range of 500 to 320 ° C.,
{Circle around (2)} The sheet temperature at the stage of a sheet thickness of 100 to 15 mm during hot rolling is set to a range of 450 to 270 ° C.,
(3) The thickness of the hot-rolled steel sheet is 1.5 to 8 mm.
{Circle around (4)} The hot-rolling finish temperature is in the range of 180 to 350 ° C.,
{Circle around (5)} The strain rate in each rolling pass at a stage after the plate thickness of 250 mm during hot rolling is set in a range of 0.2 / sec to 350 / sec,
{Circle around (6)} The dwell time between each rolling pass in the stage after the plate thickness of 250 mm during hot rolling is set to less than 10 minutes,
{Circle around (7)} The average temperature of the roll surface at the contact portion between the rolling roll and the plate at a stage after the plate thickness of 50 mm during hot rolling is set to 350 ° C. or less,
The above (1) to (7) are controlled so that hot rolling is completed, cold rolling is performed at a rolling reduction of 30% or more without intermediate annealing, and a product thickness is obtained. The rolled sheet is subjected to a solution treatment at a temperature of 480 ° C. or more for 5 minutes or less, and then cooled to a temperature range of 50 ° C. or more and less than 150 ° C. at an average cooling rate of 100 ° C./min or more. It is characterized in that a stabilization process of holding or slow cooling in the region for 2 hours or more is performed.
[0016]
The method for producing an aluminum alloy sheet for forming according to the third aspect of the present invention is the method for producing an aluminum alloy sheet for forming according to the second aspect, wherein after the stabilizing treatment, the temperature is further increased to 100 ° C./min or more. After heating to a temperature in the range of 170 to 280 ° C. at a heating rate and holding at a temperature in the range for 5 minutes or more, a final heat treatment of cooling at a cooling rate of 100 ° C./min or more is performed. It is.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the reasons for limiting the component composition in the aluminum alloy sheet for forming according to the present invention will be described.
[0018]
Mg:
Mg is a basic alloy element in the alloy of the system targeted in the present invention, and contributes to improvement in strength in cooperation with Si. When the amount of Mg is less than 0.3%, G. contributes to the improvement of the strength by precipitation hardening at the time of coating baking. P. Since the formation amount of the zone is small, sufficient strength improvement cannot be obtained. On the other hand, if it exceeds 1.0%, a coarse Mg-Si based intermetallic compound is generated, and the formability, particularly the bending workability, is reduced. Therefore, the amount of Mg was set in the range of 0.3 to 1.0%.
[0019]
Si:
Si is also a basic alloying element in the alloy of the present invention, and contributes to improvement of strength in cooperation with Mg. Further, Si is generated as a crystal of metal Si at the time of casting, and the periphery of the metal Si particles is deformed by processing and becomes a generation site of a recrystallization nucleus during solution treatment. It also contributes to the development. If the Si content is less than 0.3%, the above effect cannot be sufficiently obtained, while if it exceeds 1.5%, coarse Si particles or coarse Mg-Si-based intermetallic compound are generated, and bending workability is increased. Causes a decline. Therefore, the Si content is set in the range of 0.3 to 1.5%.
[0020]
Mn, Cr, Fe, Ti, Zn:
These elements are effective for improving the strength, refining the crystal grains, or improving the aging property and the surface treatment property, and one or more of these elements are added. Of these, Mn and Cr are elements that are effective in improving strength, refining crystal grains, and stabilizing the structure. When the content is less than 0.03%, the above effects cannot be sufficiently obtained. If the contents of Mn and Cr each exceed 0.4%, not only the above effects are saturated, but also a large number of intermetallic compounds may be generated to adversely affect the formability, particularly the hem bending property, Therefore, both Mn and Cr are in the range of 0.03 to 0.4%. Fe is also an element effective for improving the strength and refining the crystal grains. If the content is less than 0.03%, a sufficient effect cannot be obtained. On the other hand, if the content exceeds 0.5%, the formability may be reduced. Therefore, the amount of Fe was set in the range of 0.03 to 0.5%. Further, Ti is also an element effective for improving the strength and refining the ingot structure. If the content is less than 0.005%, a sufficient effect cannot be obtained, while if it exceeds 0.2%, the effect of Ti addition is not obtained. The Ti content is set in the range of 0.005 to 0.2% because not only saturation but also a large crystallized substance may be generated. Zn is an element that contributes to the improvement of the strength through the improvement of the aging property and is effective for the improvement of the surface treatment property. When the addition amount of Zn is less than 0.03%, the above effect cannot be sufficiently obtained. %, The formability decreases, so the Zn content was set in the range of 0.03 to 2.5%.
[0021]
Cu:
Cu is an element that may be added to improve strength and formability. However, if the amount exceeds 1.0%, corrosion resistance (intergranular corrosion resistance and thread rust resistance) deteriorates. The content of Cu was regulated to 1.0% or less. When the corrosion resistance is particularly important, the Cu content is desirably regulated to 0.05% or less.
[0022]
In addition to the above elements, Al and unavoidable impurities may be basically used.
[0023]
The above content ranges of Mn, Cr, Fe, Ti, and Zn are shown as ranges in the case where they are positively added, respectively, and exclude the case where any of them contains an amount smaller than the lower limit as an impurity. Not something. In particular, Fe of less than 0.03% is usually contained inevitably when ordinary aluminum ingots are used.
[0024]
Further, in the aging Al-Mg-Si alloy, a small amount of Ag, In, Cd, Be, or Sn, which is a high-temperature aging accelerating element or a room-temperature aging suppressing element, may be added. In this case, the addition of these elements is permissible. If the content of each element is 0.3% or less, the intended purpose is not particularly impaired.
[0025]
In addition, in a general Al alloy, B may be added simultaneously with the above-mentioned Ti in order to refine the crystal grains. In the case of the present invention, addition of 500 ppm or less of B together with Ti is permitted.
[0026]
Furthermore, in the aluminum alloy sheet for forming according to the present invention, in order to obtain good bending workability, particularly good hem bending property, and to avoid an increase in anisotropy, the composition of the alloy is adjusted as described above. Not only that, it is necessary to appropriately control the metal structure of the sheet, particularly the crystal orientation density, according to each region in the sheet thickness direction. That is, a region from the surface of the plate to a position corresponding to 2/5 of the total plate thickness in the plate thickness direction is defined as a plate surface side region, and a region inside the plate thickness direction (from the plate surface to the plate surface). If a region closer to the center in the thickness direction than a position corresponding to a depth of 2/5 of the total thickness in the thickness direction) is defined as the plate center side region,
{Circle around (1)} The average cube orientation density in the plate surface side region is within a range of 8 to 250 times that of the sample having a random crystal orientation;
(2) the average cube orientation density in the central region of the plate is not more than 200 times that of a sample having a random crystal orientation;
(3) that the average cube orientation density in the plate surface side region is higher than the average cube orientation density in the plate center region;
The above conditions (1) to (3) must be satisfied. The reason why the crystal orientation density is controlled according to each region in the plate thickness direction as described above is as follows.
[0027]
First, regarding the condition (1), if the average density of cube orientation in the plate surface side region is less than 8 times that of the sample having random crystal orientation, a slip line such as a shear band develops at the bending part during hem bending. However, the bending strain tends to concentrate, and cracks may be generated at the location where the strain is concentrated. Further, in this case, as compared with the direction parallel to the rolling direction or the direction perpendicular to the rolling direction, the bendability in the 45 ° direction with respect to the rolling direction is greatly reduced, and the bending anisotropy is increased. On the other hand, if the average density of the cube orientation in the plate surface side region exceeds 250 times that of the sample having the random crystal orientation, not only the effect of improving the bendability due to the crystal orientation is saturated, but also a rough surface defect during processing may occur. is there. Therefore, the average density of cube orientation in the plate surface side region is specified to be 8 times or more and 250 times or less of the sample having a random crystal orientation as described in (1).
[0028]
Next, regarding the condition (2), if the average density of the cube orientation in the central region of the sheet exceeds 200 times that of the sample having the random orientation, the anisotropy of the mechanical performance tends to be remarkable, and particularly, the rolling direction and The elongation of the tensile test specimen in the parallel direction is significantly reduced. Therefore, as described in (2) above, the average density of the cube orientation in the central region of the plate is specified to be 200 times or less that of the sample having the random orientation.
[0029]
Further, regarding the condition (3), if the average density of the cube orientation in the plate center side region is higher than the average density of the cube orientation in the plate surface side region, the anisotropy of the mechanical performance becomes strong. As described in 2), it is specified that the average cube orientation density in the plate surface side region is higher than the average cube orientation density in the plate center region.
[0030]
Here, the above conditions (1) to (3) define the cube orientation density of each region in the plate thickness direction, but the orientation density of the crystal orientation other than the cube orientation also has some degree of bendability. Affect. However, it is actually extremely difficult to finely define all the orientation densities of crystal orientations other than the cube orientation.
[0031]
On the other hand, according to the ear ratio of the cup squeezed in the plate cupping test, the crystal orientation of the material can be evaluated macroscopically. Therefore, in the present invention, the influence of the azimuth density of the crystal orientation other than the cube orientation is defined by the 0 ° ear ratio and the 90 ° ear ratio. That is, when the 0 ° ear ratio and the 90 ° ear ratio of the cup with respect to the rolling direction are less than 5%, good bendability can be obtained even if the conditions of the cube orientation densities (1) to (3) are satisfied. Therefore, the ear ratio at 0 ° and 90 ° with respect to the rolling direction was controlled to 5% or more.
[0032]
Further, in the present invention, the sum of the lengths of the small-angle grain boundaries in the crystal structure, that is, the sum of the lengths of the grain boundaries having a rotation angle in the range of 5 to 15 °, is the sum of the lengths of all the grain boundaries having a rotation angle of 5 ° or more. It must be within the range of 5 to 90% of the total length. That is, since the sum of the lengths of the small-angle grain boundaries of 5 ° or more and 15 ° or less is within a certain range with respect to the sum of the lengths of all the grain boundaries of 5 ° or more, the bending along the grain boundaries is performed. The effect of alleviating cracks is obtained. If this ratio is less than 2%, good bendability may not be obtained. On the other hand, if it exceeds 90%, the surface may be roughened at the time of molding and the surface quality of the sheet may be degraded. Therefore, in the present invention, the ratio of the small-angle grain boundaries is specified as described above in order to obtain good bending properties and good sheet surface quality.
[0033]
In addition to the above, the present invention specifies that the conductivity of the plate is 54% IACS or less. That is, in general, the electrical conductivity is an index of the amount of the solid solution element, but when the electrical conductivity exceeds 54% IACS, the amount of the solid solution Mg and Si is small, so that the aging precipitation hardening amount is sufficient. It is difficult to obtain sufficient high strength after coating baking. Therefore, in order to obtain high strength after baking, the conductivity of the plate needs to be 54% IACS or less. Although the lower limit of the electric conductivity is not particularly limited, usually, even if the electric conductivity of the alloy is set to 40% IACS or less, the effect of the baking hardenability is saturated, and it is difficult to realize this industrially. is there.
[0034]
Next, a method of manufacturing the aluminum alloy sheet for forming according to the present invention will be described.
[0035]
First, an alloy having the above-mentioned composition is melted according to a conventional method, and is cast by a normal casting method such as a DC casting method. Usually, the obtained ingot is subjected to a homogenization treatment and then subjected to hot rolling. This hot rolling is an important step that greatly affects the crystal orientation of the final product sheet, and in order to obtain a final product sheet that satisfies the above-described crystal orientation conditions, hot rolling conditions, particularly hot rolling, are required. It is necessary to regulate the conditions at each stage during the cold rolling by the following (1) to (7).
{Circle around (1)} The sheet temperature in the stage of the sheet thickness of 250 to 100 mm during the hot rolling process is set to be in the range of 500 to 320 ° C.
{Circle around (2)} The sheet temperature at the stage of the sheet thickness of 100 to 15 mm in the hot rolling process is set to be in the range of 450 to 270 ° C.
{Circle around (3)} The thickness of the hot-rolled sheet should be 1.5 to 8 mm.
{Circle around (4)} The hot rolling finish temperature is in the range of 180 to 350 ° C.
{Circle around (5)} The strain rate in each rolling pass at a stage after the plate thickness of 250 mm in the hot rolling process is in the range of 0.2 / sec to 350 / sec.
{Circle around (6)} The residence time between each rolling pass at a stage after the plate thickness of 250 mm in the hot rolling process is set to be less than 10 minutes.
{Circle around (7)} The average temperature of the roll surface at the contact portion between the rolling roll and the plate at a stage after the plate thickness of 50 mm in the hot rolling process is set to 350 ° C. or less.
[0036]
That is, during hot rolling, since the material is constantly recovered and recrystallized, the temperature, the strain rate of each rolling pass, the residence time between each rolling pass, and the surface temperature of the rolling rolls at each thickness stage Is strictly controlled as in the above (1) to (7), which is extremely important for controlling the crystal orientation. If the above conditions (1) to (7) are not satisfied, there is a possibility that a final product sheet satisfying the above-described crystal orientation density condition may not be obtained. Further, here, the plate temperature at the stage where the plate thickness is 100 to 15 mm is set to 270 ° C. or higher, the temperature of hot rolling is set to 180 ° C. or higher, and in each rolling pass at the stage where the plate thickness is 250 mm or less. Keeping the strain rate at 350 / sec or less and maintaining the average temperature of the roll surface at 350 mm or less at a stage after the plate thickness of 50 mm or less not only control the crystal orientation but also ensure the surface quality of the plate. It is also a necessary condition. The average temperature of the roll surface at the contact portion between the rolling roll and the plate is measured at three points at both ends and the center in the length direction at the contact portion between the roll and the rolling plate using a radiation thermometer, and the average value is obtained. Is the roll surface temperature. Further, it is possible to regulate the average temperature to 350 ° C. or lower by controlling the coolant injection.
[0037]
After the hot rolling is completed by strictly regulating the hot rolling conditions as described above, cold rolling is directly performed at a rolling reduction of 30% or more without performing intermediate annealing to obtain a required sheet thickness (product sheet). Thickness). If this condition is not satisfied, a product plate having the crystal orientation density condition as described above cannot be obtained. Here, by setting the cold rolling ratio to 30% or more, high strain energy is accumulated in the material, and the crystal grains formed during the solution treatment-quenching after hot rolling become fine, and after forming, Good surface appearance quality can be obtained. If the cold rolling reduction is less than 30%, surface defects such as surface roughness may occur during molding.
[0038]
After the required product thickness is obtained as described above, a solution treatment is performed at a temperature of 480 ° C. or more for 5 minutes or less. This solution treatment is performed using Mg 2 This is an important step for dissolving Si, elemental Si, or the like in the matrix, thereby imparting bake hardenability and improving the strength after baking. This step is performed by Mg 2 In order to lower the distribution density of the second phase particles by solid solution of Si, single Si particles, etc., to contribute to improving ductility and bendability, and further to obtain generally good formability by recrystallization. This is a necessary step.
[0039]
When the solution treatment temperature is lower than 480 ° C., it seems to be advantageous for suppressing the temporal change at room temperature. 2 The lower limit of the solution treatment temperature was set to 480 ° C., because not only the amount of solid solution of Si, Si and the like was reduced, and sufficient bake hardenability was not obtained, but also ductility and bendability were significantly deteriorated. On the other hand, the upper limit of the solution treatment temperature is not particularly limited, but is usually preferably 580 ° C. or less in consideration of the possibility of eutectic melting and coarsening of recrystallized grains. If the solution treatment time exceeds 5 minutes, the solution treatment effect is saturated, not only impairing the economic efficiency but also possibly causing the crystal grains to be coarse. Therefore, the solution treatment time is set to 5 minutes or less.
[0040]
After the solution treatment, it is cooled (quenched) to a temperature range of 50 to 150 ° C. at a cooling rate of 100 ° C./min or more. Here, if the cooling rate after the solution treatment is less than 100 ° C./min, 2 A large amount of Si or Si is precipitated at the grain boundary, and the moldability, particularly the hem bending property, is reduced, and the bake hardenability is reduced, so that it is not possible to expect a sufficient improvement in the strength at the time of paint baking.
[0041]
As described above, after performing the solution treatment at a temperature of 480 ° C. or more and cooling (quenching) at a cooling rate of 100 ° C./min or more in a temperature range of 50 to less than 150 ° C., to a temperature range of less than 50 ° C. Before the temperature is lowered, a stabilization process is performed in which the temperature is kept within this temperature range (less than 50 to 150 ° C.) for 2 hours or more, or the temperature is cooled (slowly cooled) for 2 hours or more in this temperature range.
[0042]
After the solution treatment and quenching to a temperature of less than 50 to 150 ° C., the stabilizing treatment is performed at a temperature of less than 50 to 150 ° C. without cooling to a temperature range of less than 50 ° C. for the following reason. That is, after the solution treatment, particularly when cooled to a room temperature of less than 50 ° C. at an average cooling rate of 100 ° C./min or more, a room temperature cluster is generated. This room temperature cluster contributes to the strength of G. P. Since it is difficult to move to the zone, it is disadvantageous to paint bake hardenability. On the other hand, when the solution is cooled to a temperature range of 150 ° C. or more and kept as it is after the solution treatment, P. Zones or stable phases are formed, and the material strength before forming becomes too high, and the hem bending property and other formability deteriorate. Therefore, from the viewpoint of the balance between the hem bending property, the formability, and the paint bake hardenability, the conditions of the solution treatment, the quenching, and the stabilization treatment are determined as described above.
[0043]
After performing the stabilization treatment as described above, it may be used as it is as a product plate, and may be subjected to a forming process for an automobile body sheet or the like, but in order to further improve paint baking hardenability and hem bending property. May be further subjected to a final heat treatment. In this final heat treatment, it is necessary to heat and hold at a heating rate of 100 ° C. or more within a temperature range of 170 to 280 ° C., and to cool at a cooling rate of 100 ° C./min or more.
[0044]
If the heating temperature of the final heat treatment is lower than 170 ° C., the above-mentioned effect of the final heat treatment cannot be obtained, while if it exceeds 280 ° C., a temporal change occurs at room temperature, and press formability deteriorates. If the heating time of the final heat treatment exceeds 5 minutes, not only the effect of the final heat treatment is saturated, but also, in some cases, the material strength before molding becomes too high due to long-term aging, and the moldability deteriorates. Further, when the heating rate to a temperature of 170 to 280 ° C. is less than 100 ° C./min, aging proceeds and the formability deteriorates. On the other hand, when the cooling rate after heating is less than 100 ° C./min, aging proceeds and grain boundary precipitation occurs. Occurs, and the formability, particularly the hem bending property, is reduced. Therefore, the condition of the final heat treatment was set within the above range.
[0045]
The conditions between the stabilization treatment and the final heat treatment in the case where the final heat treatment is performed after the stabilization treatment are not particularly limited. However, after the stabilization treatment, the material is usually left at room temperature until the final heat treatment. In this case, the room temperature standing time is preferably within one month in consideration of factors such as the temporal change of the material at room temperature.
[0046]
As described above, by strictly regulating the conditions of hot rolling, and further regulating the conditions of solution treatment-cooling-stabilization treatment from cold rolling, and further regulating the conditions of final heat treatment, as described above. Satisfies crystal orientation density condition, ear condition, and conductivity condition, and has excellent moldability, especially hem bendability, low material anisotropy, good paint bake hardenability, and changes over time due to aging at room temperature. It is possible to obtain an aging Al-Mg-Si-based aluminum alloy plate which is hardly generated.
[0047]
【Example】
The alloys A1 to A5 in the composition range of the present invention and the alloy B1 out of the composition range of the invention shown in Table 1 were cast by a DC casting method according to a conventional method. The lump was subjected to a homogenization treatment at 530 ° C. × 2 hours, and then cooled and subjected to facing, and then heated again to a temperature of 530 ° C. to start hot rolling. The hot rolling was carried out by changing various conditions from the stage of 250 mm in the middle to the ascent. Tables 2 to 4 show these detailed hot rolling conditions. The obtained hot rolled plate was subjected to cold rolling to finally obtain a rolled plate having a thickness of 1 mm. For production number 5, intermediate annealing was performed at the stage where the hot-rolled sheet was cold-rolled to a thickness of 2 mm, and then the final cold-rolled sheet was reduced to a thickness of 1 mm. Each of the obtained cold-rolled sheets is subjected to various solution treatments, and then cooled (quenched) to a predetermined temperature range at a cooling rate of 100 ° C./min or more, and subsequently subjected to various stabilizing treatments. Was. Some of them were subjected to a final heat treatment at a heating rate and a cooling rate of 100 ° C./min or more after the stabilization treatment. Table 5 shows specific process conditions after hot rolling.
[0048]
For each plate obtained as described above, the average cube orientation density in each region in the plate thickness direction was examined, and the ratio, ear ratio, and conductivity of the small angle crystal grain boundaries in the range of 5 to 15 ° were measured. . Table 6 shows the results of these measurements. In addition, these measurement conditions are as follows.
[0049]
Measurement of average cube orientation density for each area:
A 1 mm-thick plate was etched with a 10% aqueous NaOH solution from the surface to the center of the plate thickness by 50 μm each to obtain a measurement sample. The average cube orientation density in the plate surface side region (region from the plate surface to a position at a depth of 板 of the plate thickness) is 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, and 350 μm in the plate thickness direction from the surface, respectively. , 400 μm, and the average value of cube orientation densities measured at each position. The average cube orientation density in the central region of the plate (inside the position at a depth of 2/5 from the surface) is the cube orientation density measured at 450 μm and 500 μm in the thickness direction from the surface, respectively. The average value was obtained. Here, an X-ray diffractometer, Geigerflex RAD-RB, manufactured by Rigaku Corporation was used as a measuring device, and the imperfect poles of {200}, {220}, and {111} were determined by the X-ray diffraction Shetz reflection method. The figures were measured, and three-dimensional crystal orientation analysis (ODF) was performed on the basis of these figures to check. In these analyses, the data obtained by measuring a sample having a random crystal orientation made of aluminum powder is used as a standardization file used in the analysis of the {200}, {220}, and {111} pole figures. Thus, the cube orientation density was determined as a multiple of a sample having a random orientation. In the present invention, the crystal orientation densities are all based on three-dimensional crystal orientation analysis (ODF). Generally, the ideal cube orientation is {100} <001>. However, the cube orientation of an industrial material usually includes a crystal orientation shifted from the ideal orientation by 15 °. Therefore, the present invention also includes a crystal orientation within a range of 15 ° around the ideal orientation.
[0050]
Ratio of small angle grain boundaries:
The ratio of the sum of the lengths of the small angle grain boundaries having a grain boundary rotation angle of 5 ° to 15 ° and the sum of the lengths of all the grain boundaries having a grain boundary rotation angle of 5 ° or more was measured as follows. That is, analysis is performed based on crystal orientation data measured using an OIM device (EBSP method) manufactured by Tex Laboratories, and a misorientation angle and a ratio of the misorientation angle to the number (number fraction) are used. Examined. The measurement area was a region having a width of 400 μm and a length of 500 μm covering a central portion of the plate thickness from the surface of the plate in a cross section parallel to the rolling direction.
[0051]
Ear rate:
After applying lubricating oil to the plate, the cup was squeezed under the conditions of a punch diameter of 32 mm, a blank diameter of 62 mm, and a blank holder of 20 kg, and the ear ratio of the cup was examined. Here, the direction of the ear ratio indicates an angle based on the rolling direction.
[0052]
Conductivity (% IACS):
The measurement was performed using copper and brass as reference samples using an eddy current conductivity measuring device.
[0053]
Further, each plate obtained as described above was allowed to stand at room temperature for one month after the plate was manufactured, and after each plate was stretched by 2%, paint baking treatment was performed at 170 ° C. for 20 minutes. Each plate before paint baking is subjected to a tensile test to check the mechanical properties (proof stress, elongation) and hem bendability. Further, each plate after paint baking is also subjected to a tensile test to determine its mechanical properties (proof stress). Was examined. Table 7 shows the results. The test conditions and evaluation method are as follows.
[0054]
Tensile test:
JIS No. 5 tensile test pieces of JIS Z2201 were sampled in three directions of 0 °, 45 °, and 90 ° with respect to the rolling direction of the material, and a tensile test was performed in accordance with JIS Z2241.
[0055]
Hem bending test:
Bending test specimens were taken in three directions of 0 °, 45 ° and 90 ° with respect to the rolling direction of the material, stretched by 15%, and pierced. Was performed. As the evaluation, a case where no crack was visually recognized was regarded as a pass (marked with “○”), and a case where cracks were visually recognized was determined as “fail” (marked with “x”).
[0056]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
[Table 6]
[Table 7]
In Tables 1 to 7, Production Nos. 1 and 2 are those in which the component composition of the alloy is within the range specified in the present invention and the manufacturing conditions also satisfy the conditions specified in the present invention. It has excellent hem bending properties, small elongation anisotropy and bending anisotropy before baking, and has high bake hardenability, showing sufficient bake hardenability during bake.
[0064]
On the other hand, in production numbers 3 to 5, the composition of the alloy is all within the range specified in the present invention, but the manufacturing conditions did not satisfy the conditions specified in the present invention. The conditions are within the range specified by the present invention, but are comparative examples in which the component composition of the alloy is out of the range specified by the present invention.
[0065]
Among these comparative examples, Production No. 3 had low 0 ° and 90 ° ear ratios, high electrical conductivity, and as a result, strong bending anisotropy and insufficient strength after baking. In Production No. 4, the average cube orientation density in the central region of the plate was too high, the elongation and bending anisotropy were strong, and the strength after coating baking was not sufficiently obtained. Further, in Production No. 5, although the anisotropy was small, the hem bendability itself was inferior, and the strength after baking was not sufficiently obtained. Production No. 6 had high strength after baking of paint and low anisotropy in elongation and bending, but had poor hem bendability itself.
[0066]
【The invention's effect】
According to the present invention, the formability, especially the hem bendability, is excellent, and at the same time, the material anisotropy such as the anisotropy of the hem bendability and the anisotropy of the mechanical performance is small, and the paint baking hardenability is low. Good aluminum alloy plate for forming process with good strength after paint baking and little change over time at room temperature.Therefore, it can be used for car body sheet etc. after forming process, especially hem bending process and paint baking. It is most suitable for aluminum alloy plate to be used.
Claims (3)
▲１▼熱間圧延途中の板厚２５０〜１００ｍｍの段階における板温度を５００〜３２０℃の範囲内とし、
▲２▼熱間圧延途中の板厚１００〜１５ｍｍの段階における板温度を４５０〜２７０℃の範囲内とし、
▲３▼熱間圧延の上がり板厚を１．５〜８ｍｍとし、
▲４▼熱間圧延上がり温度を１８０〜３５０℃の範囲内とし、
▲５▼熱間圧延中における板厚２５０ｍｍ以降の段階の各圧延パスにおける歪み速度を０．２／秒〜３５０／秒の範囲内とし、
▲６▼熱間圧延中における板厚２５０ｍｍ以降の段階の各圧延パス間の滞留時間を１０分未満とし、
▲７▼熱間圧延中の板厚５０ｍｍ以降の段階における圧延ロールと板との接触部分のロール表面の平均温度を３５０℃以下とし、
以上▲１▼〜▲７▼が満たされるように制御して熱間圧延を終了させ、
さらに中間焼鈍を施すことなく圧延率３０％以上で冷間圧延を施して製品板厚とした後、その圧延板に対し、４８０℃以上の温度での５分以内の溶体化処理を行なってから１００℃／ｍｉｎ以上の平均冷却速度で５０℃以上１５０℃未満の温度域まで冷却し、続いてその温度域内において２時間以上で保持もしくは徐冷する安定化処理を行なうことを特徴とする、曲げ加工その他の成形性および焼付硬化性に優れかつ伸びと曲げ異方性の少ない成形加工用アルミニウム合金板の製造方法。Mg 0.3-1.0%, Si 0.3-1.5%, Mn 0.03-0.4%, Cr 0.03-0.4%, Fe 0.03-0.5%, Ti0 0.005 to 0.2%, one or two or more selected from 0.03 to 2.5% of Zn, Cu is restricted to 1% or less, and the balance is less than Al and unavoidable impurities. Hot rolling of an aluminum alloy ingot
{Circle around (1)} The sheet temperature at the stage of a sheet thickness of 250 to 100 mm during hot rolling is set to a range of 500 to 320 ° C.,
{Circle around (2)} The sheet temperature at the stage of a sheet thickness of 100 to 15 mm during hot rolling is set to a range of 450 to 270 ° C.,
(3) The thickness of the hot-rolled steel sheet is 1.5 to 8 mm.
{Circle around (4)} The hot-rolling finish temperature is in the range of 180 to 350 ° C.,
{Circle around (5)} The strain rate in each rolling pass at a stage after the plate thickness of 250 mm during hot rolling is set in a range of 0.2 / sec to 350 / sec,
{Circle around (6)} The dwell time between each rolling pass in the stage after the plate thickness of 250 mm during hot rolling is set to less than 10 minutes,
{Circle around (7)} The average temperature of the roll surface at the contact portion between the rolling roll and the plate at a stage after the plate thickness of 50 mm during hot rolling is set to 350 ° C. or less,
The hot rolling is terminated by controlling so that the above (1) to (7) are satisfied,
Further, after performing cold rolling at a rolling reduction of 30% or more to a product sheet thickness without performing intermediate annealing, the rolled sheet is subjected to a solution treatment at a temperature of 480 ° C. or more within 5 minutes. Bending characterized by cooling to a temperature range of 50 ° C. or more and less than 150 ° C. at an average cooling rate of 100 ° C./min or more, and then performing stabilization treatment of holding or slow cooling in the temperature range for 2 hours or more. A method for producing an aluminum alloy sheet for forming which has excellent processing and other formability and bake hardenability and has low elongation and bending anisotropy.
前記安定化処理の後、さらに１００℃／ｍｉｎ以上の加熱速度で１７０〜２８０℃の範囲内の温度に加熱してその範囲内の温度で５分以上保持した後、１００℃／ｍｉｎ以上の冷却速度で冷却する最終熱処理を施すことを特徴とする、曲げ加工その他の成形性および焼付硬化性に優れかつ伸びと曲げ異方性の少ない成形加工用アルミニウム合金板の製造方法。The method for producing an aluminum alloy sheet for forming according to claim 2,
After the stabilization treatment, the mixture is further heated to a temperature in the range of 170 to 280 ° C. at a heating rate of 100 ° C./min or more and maintained at a temperature in the range for 5 minutes or more, and then cooled at 100 ° C./min or more. A method for producing an aluminum alloy sheet for forming, which is excellent in bending and other formability and bake hardenability and has low elongation and bending anisotropy, characterized by performing a final heat treatment of cooling at a high speed.
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| JP2008303455A (en) * | 2007-06-11 | 2008-12-18 | Sumitomo Light Metal Ind Ltd | MANUFACTURING METHOD OF Al-Mg-Si BASED ALUMINUM ALLOY PLATE FOR PRESS MOLDING AND Al-Mg-Si BASED ALUMINUM ALLOY PLATE FOR PRESS MOLDING |
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| JP2016533901A (en) * | 2013-10-25 | 2016-11-04 | エス・エム・エス・グループ・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング | Aluminum hot strip rolling train and method for hot rolling aluminum hot strip |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008303455A (en) * | 2007-06-11 | 2008-12-18 | Sumitomo Light Metal Ind Ltd | MANUFACTURING METHOD OF Al-Mg-Si BASED ALUMINUM ALLOY PLATE FOR PRESS MOLDING AND Al-Mg-Si BASED ALUMINUM ALLOY PLATE FOR PRESS MOLDING |
| CN104093868A (en) * | 2012-02-10 | 2014-10-08 | 株式会社神户制钢所 | Aluminum alloy sheet for connecting components and manufacturing process therefor |
| CN104093868B (en) * | 2012-02-10 | 2016-11-30 | 株式会社神户制钢所 | Connection member aluminium alloy plate and manufacture method thereof |
| JP2016533901A (en) * | 2013-10-25 | 2016-11-04 | エス・エム・エス・グループ・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング | Aluminum hot strip rolling train and method for hot rolling aluminum hot strip |
| CN103911533A (en) * | 2014-04-26 | 2014-07-09 | 广东兴发铝业有限公司 | Formula of 6061 aluminum alloy extrusion section for refrigerated container |
| JP2016023354A (en) * | 2014-07-24 | 2016-02-08 | 株式会社Uacj | Aluminum alloy sheet for hot roll molding and manufacturing method therefor |
| CN110714147A (en) * | 2019-11-05 | 2020-01-21 | 郑州明泰实业有限公司 | 6082 aluminum alloy plate for aviation and production process thereof |
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