JP3644818B2

JP3644818B2 - Method for producing aluminum alloy plate for can body

Info

Publication number: JP3644818B2
Application number: JP07330898A
Authority: JP
Inventors: 岩朱
Original assignee: Furukawa Sky Aluminum Corp
Current assignee: Furukawa Sky Aluminum Corp
Priority date: 1998-03-06
Filing date: 1998-03-06
Publication date: 2005-05-11
Anticipated expiration: 2018-03-06
Also published as: JPH11256290A

Description

【０００１】
【発明の属する技術分野】
この発明はＤＩ加工（絞り−しごき加工）による２ピースアルミニウム缶用の缶胴、すなわちＤＩ缶胴に用いられるＡｌ−Ｍｇ−Ｍｎ系アルミニウム合金板の製造方法に関し、特に深絞り耳が低くかつ塗装焼付後の強度が高く、しかもＤＩ加工時の成形性および塗装焼付後の成形性に優れたＤＩ缶胴用アルミニウム合金板の製造方法に関するものである。
【０００２】
【従来の技術】
一般に２ピースアルミニウム缶の製造工程としては、缶胴素材に対して深絞り加工およびしごき加工によるＤＩ成形を施して缶胴形状とした後、所定のサイズにトリミングを施して脱脂・洗浄処理を行ない、さらに塗装および印刷を行なって焼付け（ベーキング）を行ない、その後、缶胴縁部に対してネッキング加工、フランジング加工を行ない、その後、別に成形した缶蓋（缶エンド）と合せてシーミング加工を行なって缶とするのが通常である。
【０００３】
このようにして製造されるＤＩ缶の素材（缶胴材）としては、従来からＡｌ−Ｍｇ−Ｍｎ系合金であるＪＩＳ３００４合金の硬質板が広く用いられている。この３００４合金は、しごき加工性に優れていて、強度を高めるために高圧延率で冷間圧延を施した場合でも比較的良好な成形性を示すところから、ＤＩ缶胴材として好適であるとされている。
【０００４】
このようなＤＩ缶胴用の３００４合金硬質板の製造方法としては、ＤＣ鋳造法などによって鋳造後、鋳塊に対し均質化処理を施し、さらに熱間圧延および冷間圧延を施して所定の板厚とし、かつその過程における冷間圧延前あるいは冷間圧延中途において中間焼鈍を施す方法が一般的である。
【０００５】
ところでＤＩ缶胴については、主として材料コスト低減、軽量化の目的から、より薄肉化を図ることが強く望まれている。そしてこのように薄肉化を図るためには、薄肉化に伴なって生じる缶の座屈強度低下の問題を回避するため、材料の高強度化を図ることが不可欠である。
【０００６】
またＤＩ缶胴用材料については、上述のような薄肉化を図るための高強度化の要請ばかりではなく、ＤＩ成形時における耳率が低いことが強く望まれる。すなわち、ＤＩ成形時の耳率が低いことは、ＤＩ成形時の歩留りの向上と、缶胴の耳切れに起因する缶胴破断の防止の点から必要とされている。さらに、耳率を如何に制御するかによって、強度、フランジ成形性、耳率のバランスに影響を及ぼすことになるから、耳率制御は缶胴材にとって極めて重要な課題となっている。
【０００７】
しかしながら、前述のような従来の一般的な缶胴材製造方法では、耳率を抑えるにも限界があり、例えば絞り比１．９において耳率を３％以下に抑えることは困難であった。
【０００８】
そこで低耳率を達成するための缶胴材製造方法が、既に例えば特開平５−３１７９１４号、特開平９−２４９９３２号、特開平９−２６８３５５号等において提案されている。
【０００９】
【発明が解決しようとする課題】
前述の特開平５−３１７９１４号においては、冷間圧延中途において２回焼鈍を行なう方法が提案されているが、このように冷間圧延中途において２回焼鈍を行なった場合、最終冷間圧延の圧延率を大きくとれないため、強度不足が生じやすいという問題があるほか、製缶時の材料の加工硬化量が大きく、フランジ成形性が悪化する問題がある。
【００１０】
また特開平９−２４９９３２号においては、熱間圧延の最終パスにおける圧延速度、減面率、および熱延終了温度を厳密に規制することによって低耳率を達成する方法が提案されており、この方法は、ある程度は低耳率達成に有効であるが、依然として製造チャンスによる耳率の変動は大きく、確実かつ安定して低耳率を得るには不充分であった。
【００１１】
さらに、特開平９−２６８３５５号においては、熱間仕上圧延にタンデム式圧延機を用いる場合について、熱間仕上圧延条件を細かく規制することにより低耳率を達成する方法が提案されているが、この発明の方法は仕上圧延にタンデム式圧延機を用いた場合に限られるものであって、リバーシングミルを用いる場合については全く考慮されておらず、したがって熱間圧延にリバーシングミルを適用した場合の耳率制御には有効ではない。
【００１２】
以上のように、従来提案されている方法は、缶胴材に対する諸要求を全て充分に満たすことは困難であり、特にリバーシングミルを用いた場合であっても缶胴材として必要な諸特性を充分に満たす材料を得ることは困難であった。
【００１３】
この発明は以上の事情を背景としてなされたものであって、缶胴材として望まれる諸要求を充分に満足し得る材料、すなわち薄肉化を図った場合でも強度とフランジ成形性に優れ、しかも深絞りにおける材料の耳率が確実かつ安定して低い缶胴用アルミニウム合金板を製造し得る方法を提供することを基本的な目的とするものである。
【００１４】
またこの発明は、熱間圧延設備としてリバーシングミルを用いた場合にも、上述のような缶胴材として優れた性能を有するアルミニウム合金板を製造し得る方法を提供することを目的とする。
【００１５】
【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、本願発明者等が種々実験・検討を重ねた結果、熱間圧延工程の諸条件、特に熱間粗圧延における諸条件を厳密に規制することによって熱間粗圧延中における再結晶を適切に制御し、併せて再結晶後の仕上圧延の諸条件を規制することによって、前述の課題を解決し得ることを見出し、この発明をなすに至ったのである。
【００１６】
具体的には、請求項１の発明の缶胴用アルミニウム合金板の製造方法は、Ｍｇ０．５〜２．０％、Ｍｎ０．５〜２．０％、Ｆｅ０．１〜０．７％、Ｓｉ０．０５〜０．５％を含有し、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をスラブに鋳造した後、そのスラブに対し５２０〜６３０℃の範囲内の温度で１時間以上の均質化処理を施し、さらにリバーシングミルを用いて、スラブを熱間粗圧延およびそれに続く熱間仕上圧延によって熱間圧延するにあたり、
（１）熱間粗圧延開始時のスラブ厚みを２００ｍｍ以上とし、
（２）熱間粗圧延開始温度を４５０〜５８０℃の範囲内とし、
（３）熱間粗圧延から熱間仕上圧延を通じての各圧延パスにおける圧延速度を４０ｍ／分以上とし、
（４）熱間粗圧延開始時のスラブ厚みから板厚１５０ｍｍに達するまでの熱間粗圧延各パスにおける圧下量をそれぞれ１５ｍｍ以上とし、
（５）熱間粗圧延中において、粗圧延開始からの圧延率が２５％以上でかつ１５０〜１５ｍｍの範囲内の板厚の段階までの温度を、４００℃以上の温度として、その１５０〜１５ｍｍの範囲内の板厚の段階において板全体に対し体積率で５％以上の再結晶を少なくとも１回以上生じさせ、
（６）前記５％以上の再結晶体積率の段階から熱間仕上圧延における最終パスまでの温度を２５０〜４００℃の範囲内とし、
（７）さらに熱間仕上圧延における上り温度を２００〜３２０℃の範囲内とし、
（８）かつ熱間仕上圧延における上り板厚を１．０〜７．０ｍｍの範囲内とし、
以上の（１）〜（８）の条件によって得られた熱延板に対して、０．１℃／秒以下の平均昇温速度で加熱して２５０〜４５０℃の範囲内の温度に０．５時間以上保持するバッチ焼鈍を行なった後、０．１℃／秒以下の平均冷却速度で冷却し、その後さらに６０％以上の圧延率で冷間圧延を行なうことを特徴とするものである。
【００１７】
また請求項２の発明の缶胴用アルミニウム合金板の製造方法は、素材アルミニウム合金として、Ｍｇ０．５〜２．０％、Ｍｎ０．５〜２．０％、Ｆｅ０．１〜０．７％、Ｓｉ０．０５〜０．５％を含有し、かつＣｕ０．０５〜０．５％、Ｃｒ０．０５〜０．３％、Ｚｎ０．０５〜０．５％のうちの１種または２種以上を含有し、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を用い、請求項１で規定するプロセス条件と同様の条件の均質化処理−熱間圧延（粗圧延及び仕上圧延）−バッチ焼鈍−最終冷間圧延のプロセスで製造するものである。
【００１８】
さらに請求項３の発明の缶胴用アルミニウム合金板の製造方法は、素材合金として請求項１で規定する合金と同じアルミニウム合金を用い、かつ均質化処理−熱間圧延（粗圧延及び仕上圧延）を請求項１で規定する条件で行ない、その後の焼鈍として、１〜１００℃／秒の範囲内の平均昇温速度で３３０〜５００℃の範囲内の温度に加熱して保持なしもしくは１０分以下の保持の連続焼鈍を施した後、１〜１００℃／秒の範囲内の平均冷却速度で冷却し、さらにその後請求項１の方法と同様に６０％以上の圧延率で冷間圧延を行なうものである。
【００１９】
そしてまた請求項４の発明の缶胴用アルミニウム合金板の製造方法は、素材アルミニウム合金として請求項２で規定する成分組成と同じ成分組成の合金を用い、請求項３で規定するプロセスで製造するものである。
【００２０】
一方、請求項５の発明の缶胴用アルミニウム合金板の製造方法は、素材アルミニウム合金として、Ｍｇ０．５〜２．０％、Ｍｎ０．５〜２．０％、Ｆｅ０．１〜０．７％、Ｓｉ０．０５〜０．５％を含有し、さらに０．００５〜０．２０％のＴｉを単独でもしくは０．０００１〜０．０５％のＢと組合せて含有し、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を用い、請求項１で規定するプロセス条件と同様の条件の均質化処理−熱間圧延（粗圧延及び仕上圧延）−バッチ焼鈍−最終冷間圧延のプロセスで製造するものである。
【００２１】
また請求項６の発明の缶胴用アルミニウム合金板の製造方法は、素材アルミニウム合金として、Ｍｇ０．５〜２．０％、Ｍｎ０．５〜２．０％、Ｆｅ０．１〜０．７％、Ｓｉ０．０５〜０．５％を含有し、かつＣｕ０．０５〜０．５％、Ｃｒ０．０５〜０．３％、Ｚｎ０．０５〜０．５％のうちの１種または２種以上を含有し、さらに０．００５〜０．２０％のＴｉを単独でもしくは０．０００１〜０．０５％のＢと組合せて含有し、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を用い、請求項１で規定するプロセス条件と同様の条件の均質化処理−熱間圧延（粗圧延及び仕上圧延）−バッチ焼鈍−最終冷間圧延のプロセスで製造するものである。
【００２２】
さらに請求項７の発明の缶胴用アルミニウム合金板の製造方法は、素材合金として請求項５で規定する合金と同じアルミニウム合金を用い、請求項３で規定するプロセス条件と同様の条件の均質化処理−熱間圧延（粗圧延および仕上圧延）−連続焼鈍−最終冷間圧延のプロセスで製造するものである。
【００２３】
そしてまた請求項８の発明の缶胴用アルミニウム合金板の製造方法は、素材アルミニウム合金として請求項６で規定する成分組成と同じ成分組成の合金を用い、請求項３で規定するプロセスで製造するものである。
【００２４】
なお、以上の各請求項１〜８の方法において、５％以上の再結晶体積率の段階から熱間仕上圧延における最終パスまでの温度を２５０〜４００℃の範囲内に維持するため、熱間圧延中において板に対し中間冷却を施しても良く、これを規定したのが請求項９の発明である。
【００２５】
さらに請求項１〜８の方法において、６０％以上の圧延率で最終冷間圧延を行なった後には、さらに８０〜２００℃の範囲内の温度で０．５時間以上保持する最終焼鈍を施しても良く、これを規定したのが請求項１０の発明である。
【００２６】
【発明の実施の形態】
先ずこの発明の方法において用いられるアルミニウム合金の成分組成の限定理由について説明する。
【００２７】
Ｍｇ：
Ｍｇの添加は、Ｍｇそれ自体の固溶による強度向上に効果があり、またＭｇの固溶に伴なって加工硬化量の増大による強度向上が期待でき、さらにはＳｉとの共存によるＭｇ₂Ｓｉの時効析出による強度向上も期待でき、したがってＭｇは缶胴材として必要な強度を得るためには不可欠の元素である。またＭｇは、加工時の転位の増殖作用があるため、再結晶粒を微細化させるためにも有効である。但しＭｇ量が０．５％未満では上述の効果が少なく、一方２．０％を越えれば、高強度は容易に得られるものの、ＤＩ加工時の変形抵抗が大きくなって絞り性やしごき性を悪くする。したがってＭｇ量は０．５〜２．０％の範囲内とした。
【００２８】
Ｍｎ：
Ｍｎは強度および成形性の向上に寄与する有効な元素である。特にこの発明で目的としている用途である缶胴材ではＤＩ成形時にしごき加工が加えられるため、とりわけＭｎは重要となる。アルミニウム板のしごき加工においては通常エマルジョンタイプの潤滑剤が用いられているが、Ｍｎ系晶出物が少ない場合には同程度の強度を有していてもエマルジョンタイプ潤滑剤だけでは潤滑能が不足し、ゴーリングと呼ばれる擦り疵や焼付きなどの外観不良が発生するおそれがある。この現象は晶出物の大きさ、量、種類に影響されることが知られており、その晶出物を形成するためにＭｎは不可欠な元素である。Ｍｎ量が０．５％未満ではＭｎ系化合物による固体潤滑的な効果が得られず、一方Ｍｎ量が２．０％を越えればＡｌ₆Ｍｎの初晶巨大金属間化合物が発生し、著しく成形性を損なう。そこでＭｎ量は０．５〜２．０％の範囲内とした。
【００２９】
Ｆｅ：
Ｆｅは、Ｍｎの晶出や析出を促進して、アルミニウム基地中のＭｎ固溶量やＭｎ系金属間化合物の分散状態を制御するために必要な元素である。適正な化合物分散状態を得るためには、Ｍｎ添加量に応じてＦｅを添加することが必要である。Ｆｅ量が０．１％未満では適正な化合物分散状態を得ることが困難であり、一方Ｆｅ量が０．７％を越えれば、Ｍｎ添加に伴なって初晶巨大金属間化合物が発生しやすくなり、成形性を著しく損なう。そこでＦｅ量の範囲は０．１〜０．７％とした。
【００３０】
Ｓｉ：
Ｓｉの添加は、Ｍｇ₂Ｓｉ系化合物の析出による時効硬化を通じて缶胴材の強度向上に寄与する。またＳｉは、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を生成して、Ｍｎ系金属間化合物の分散状態を制御するために必要な元素である。Ｓｉ量が０．０５％未満では上記の効果が得られず、一方０．５％を越えれば時効硬化により材料が硬くなりすぎて成形性を阻害する。そこでＳｉ量の範囲は０．０５〜０．５％とした。
【００３１】
Ｔｉ，Ｂ：
通常のアルミニウム合金においては、鋳塊結晶粒微細化のためにＴｉ、あるいはＴｉおよびＢを微量添加することが行なわれており、この発明においても、必要に応じて微量のＴｉを単独で、あるいはＢと組合せて添加しても良い。但しＴｉ量が０．００５％未満ではその効果が得られず、０．２０％を越えれば巨大なＡｌ−Ｔｉ系金属間化合物が晶出して成形性を阻害するため、Ｔｉを添加する場合のＴｉ量は０．００５〜０．２０％の範囲内とした。またＴｉとともにＢを添加すれば鋳塊結晶粒微細化の効果が向上するが、Ｔｉと併せてＢを添加する場合、Ｂ量が０．０００１％未満ではその効果がなく、０．０５％を越えればＴｉ−Ｂ系の粗大粒子が混入して成形性を害することから、ＴｉとともにＢを添加する場合のＢ量は０．０００１〜０．０５％の範囲内とした。
【００３２】
Ｃｕ，Ｃｒ，Ｚｎ：
これらはいずれも強度向上に寄与する元素であり、必要に応じてこれらのうちから選ばれた１種または２種以上が添加される。これらの各元素についてさらに説明する。
【００３３】
Ｃｕ：
Ｃｕは、焼鈍時にアルミニウム基地中に溶体化させておき、塗装焼付処理時にＡｌ−Ｃｕ−Ｍｇ系析出物として析出することによる析出硬化を利用した強度向上に寄与する。Ｃｕ量が０．０５％未満ではその効果が得られず、一方Ｃｕを０．５％を越えて添加した場合には、時効硬化は容易に得られるものの、硬くなりすぎて成形性を阻害し、また耐食性も劣化する。そこでＣｕ量の範囲は０．０５〜０．５％とした。
【００３４】
Ｃｒ；
Ｃｒも強度向上に効果的な元素であるが、０．０５％未満ではその効果が少なく、０．３％を越えれば巨大晶出物生成によって成形性の低下を招くため、好ましくない。そこでＣｒ量の範囲は０．０５〜０．３％とした。
【００３５】
Ｚｎ：
Ｚｎの添加はＡｌ−Ｍｇ−Ｚｎ系粒子の時効析出による強度向上に寄与するが、０．０５％未満ではその効果が得られず、０．５％を越えれば、強度への寄与については問題がないが、耐食性を劣化させる。そこでＺｎ量の範囲は０．０５〜０．５％とした。
【００３６】
以上の各元素の残部はＡｌと不可避不純物すれば良い。
【００３７】
次にこの発明における製造プロセスを、その作用とともに説明する。
【００３８】
先ず前述のような合金組成を有するアルミニウム合金鋳塊を常法に従ってＤＣ鋳造法（半連続鋳造法）などにより鋳造する。次いでその鋳塊に対して均質化処理を施して、鋳塊の偏析を均質化するとともにＭｎ系の第２相粒子サイズと分布を最適化する。均質化処理温度が５２０℃未満では均質化の効果が不充分であり、一方６３０℃を越えれば共晶融解のおそれがある。均質化処理は１時間未満では均質化が不充分となる。したがって均質化処理は５２０〜６３０℃の範囲内の温度で１時間以上行なう必要がある。なお均質化処理時間の上限は特に規制しないが、経済性を考慮して通常は４８時間以下にすることが好ましい。
【００３９】
均質化処理を施したスラブに対しては、熱間圧延を行なう。この熱間圧延は、粗圧延とそれに続く仕上圧延とに区分されるが、この発明の方法の場合、粗圧延にリバーシングミル（可逆式圧延機）を用い、仕上圧延にもリバーシングミル（可逆式仕上圧延機；リバーシングウォームミルを含む）を用いる場合を対象としている。
【００４０】
この熱間圧延工程の条件は、この発明の方法の場合極めて重要であり、（１）〜（８）の条件に従って熱間圧延を行なうことが耳率の制御に対して重要である。そこでこれらの（１）〜（８）の条件について詳細に説明する。
【００４１】
（１）熱間粗圧延開始時のスラブ厚みを２００ｍｍ以上とする。
この熱間粗圧延時のスラブ厚みは、後述する（４）項の条件と密接に関係し、板厚１５０ｍｍに達するまでの熱間粗圧延前半の圧下量を確保して、転位を充分に蓄積させるためには、熱間粗圧延開始時のスラブ厚みを２００ｍｍ以上としておく必要があり、好ましくは充分な圧下量を得るために４００ｍｍ以上とする。なおこの熱間粗圧延前半における転位の蓄積については、（３）項、（４）項において詳細に説明する。
【００４２】
（２）熱間粗圧延開始温度を４５０〜５８０℃の範囲内とする。
熱間粗圧延の開始温度は、熱間圧延中の材料の回復および再結晶の挙動に強い影響を及ぼし、特に最終板の深絞り耳を低くするために必要なキューブ方位の結晶組織（キューブ方位の結晶粒の集合体を以下キューブバンドと称する）の形成に重要な役割を果たしている。熱間粗圧延開始温度が４５０℃未満ではキューブバンドの形成量が不足しやすく、一方５８０℃を越えた高温で熱間粗圧延を開始すれば、キューブバンドの形成は容易となるものの、板の表面品質が低下する。したがって熱間粗圧延開始温度は４５０〜５８０℃の範囲内とする必要がある。
【００４３】
（３）熱間粗圧延から熱間仕上圧延を通じての各圧延パスにおける圧延速度を４０ｍ／分以上とする。
圧延速度は圧延温度および圧下量と相俟って材料の回復および再結晶挙動、特に結晶粒および亜結晶粒のサイズに強い影響を及ぼす。圧延速度が４０ｍ／分未満では転位が蓄積されにくく、結晶粒、亜結晶粒が粗大となる傾向を示し、キューブバンドの数も少なくなり、材料の耳率および機械的特性に対して悪い影響を及ぼす。また圧延速度が低ければ生産性も低下する。したがって圧延速度は４０ｍ／分以上とする必要があり、より好適には７０ｍ／分以上とする。圧延速度の上限は特に規制しないが、良好な表面品質を得るためには、通常は１０００ｍ／分以下が好ましい。なお、ここで圧延速度とは、熱間粗圧延の各パスから熱間仕上圧延の各パスまで全てのパスでの圧延速度を意味する。したがってこの発明の方法の場合、熱間粗圧延、仕上圧延の全てのパスについて圧延速度を４０ｍ／分以上、好ましくは７０ｍ／分以上とする。
【００４４】
（４）熱間粗圧延開始時のスラブ厚みから板厚１５０ｍｍに達するまでの熱間粗圧延各パスにおける圧下量をそれぞれ１５ｍｍ以上とする。
熱間粗圧延開始時のスラブ厚み（前述のように２００ｍｍ以上、好ましくは４００ｍｍ以上）から板厚１５０ｍｍまでは、熱間粗圧延のほぼ前半の段階に相当するが、この段階における各パスでの圧下量は、圧延温度および圧延速度と相俟って材料の回復および再結晶挙動、特に結晶粒サイズ、亜結晶粒サイズに強い影響を及ぼす。この段階における各パスの圧下量が１５ｍｍ未満では転位が蓄積されにくく、結晶粒・亜結晶粒が粗大となる傾向を示し、またキューブバッドの数も少なく、材料の耳率および機械的特性に悪影響を及ぼす。そこで各パスでの圧下量は１５ｍｍ以上、好ましくは４０ｍｍ以上とする。各パスの圧下量の上限は特に規制しないが、良好な表面品質を保つため、通常は各パスの圧下量を１００ｍｍ以下とすることが好ましい。
【００４５】
（５）熱間粗圧延中において、粗圧延開始からの圧延率が２５％以上でかつ１５０〜１５ｍｍの範囲内の板厚の段階までの温度を、４００℃以上の温度として、その段階において板全体に対し体積率で５％以上の再結晶を少なくとも１回以上生じさせる。
この発明の方法においては、熱間粗圧延中において、熱間粗圧延率が２５％以上でかつ板厚が１５０〜１５ｍｍの範囲内の段階で板全体に対し体積率で５％以上の再結晶を少なくとも１回以上生じさせることが、耳率の制御にとって不可欠である。すなわち、熱間粗圧延率が２５％以上でかつ板厚が１５０〜１５ｍｍの範囲内の段階での再結晶により形成されたキューブバンドは安定であって熱延上り板にも残存し、最終冷間圧延後の最終板の耳率の低減に有効となる。そしてこのように体積率５％以上の再結晶を生じさせるためには、上述の段階での圧延温度を４００℃以上としておく必要がある。その段階での圧延温度が４００℃より低くなれば、体積率５％以上の再結晶を生起させることが困難となる。したがってこの発明では、熱間粗圧延中において熱間粗圧延開始からの圧延率が２５％以上であってかつ板厚が１５０〜１５ｍｍの範囲内の段階までの圧延温度を４００℃以上（当然のことながら熱間粗圧延開始温度以下）に制御して、その段階で板全体に対する体積率で５％以上の再結晶を少なくとも１回生起させることとしたのである。
【００４６】
なおここで、熱間粗圧延開始からの熱間粗圧延率が２５％未満の段階では、歪が少なく、板厚１５０〜１５ｍｍの範囲内で体積率５％以上の再結晶を起こさせることが困難である。また１５０ｍｍより厚い段階で再結晶を起こさせること自体は、この発明の効果に対して特に悪影響はないが、１５０ｍｍより厚い段階で再結晶を起こさせて、その後の板厚１５０〜１５ｍｍの範囲内の段階で体積率５％以上の再結晶を生じさせなかった場合には、耳率の制御の効果が充分に得られない。したがって体積率５％以上の再結晶を生じさせる段階は、粗圧延率が２５％以上でかつ板厚が１５０〜１５ｍｍの範囲内の段階とした。なおこの段階で体積率５％以上の再結晶は２回以上生じさせても良いことはもちろんである。またこの段階で生じさせる再結晶は、前述のように板全体に対する体積率で５％以上が必要であるが、より好ましくは、体積率１５％以上の再結晶を生じさせることが望ましい。そしてまた、この段階で体積率５％以上、好ましくは体積率１５％以上の再結晶を生じさせるためには、前述のようにその段階まで圧延温度を４００℃以上としておく必要があるが、確実に体積率５％以上の再結晶を生じさせるために、必要に応じて熱間粗圧延中途において４００℃以上で１２００秒以内の保持を行なっても良い。
【００４７】
（６）前記体積率５％以上の再結晶を生起させた段階から熱間仕上圧延における最終パスまでの温度を２５０〜４００℃の範囲内とすること。
前記（５）項で述べたように板厚１５０〜１５ｍｍの段階で体積率５％以上の再結晶を生起させた状態から、熱間仕上圧延最終パス入口までの間においては、適切な転位密度の蓄積を行なう必要がある。すなわち、板厚が１５０〜１５ｍｍの範囲内の段階で形成されたキューブバンド組織の周辺に適切な密度で転位を導入することにより、熱間圧延上りの状態での自己保有熱による自己焼鈍、さらにはその後のバッチ焼鈍もしくは連続焼鈍においてキューブ方位の結晶組織の成長を図ることができ、ひいては最終冷間圧延後の最終板の耳率を低く規制することに有利となる。ここで、体積率５％以上の再結晶状態から熱間仕上圧延最終パスまでの間に圧延温度が２５０℃より低くなった場合は、表面品質が低下するとともに、粗大粒子周辺の再結晶核生成数が増加し、その後の再結晶でキューブ方位以外の再結晶粒が多くなり、低耳率制御に不利となる。一方その間の温度が４００℃を越える場合、回復、再結晶が進みやすく、充分な転位を導入することが困難となる。したがって体積率５％以上の再結晶状態から熱間仕上圧延最終パス入口までの温度を２５０〜４００℃の範囲内に制御する必要があるが、この範囲内でも特に２７０〜３７０℃の範囲内が好適である。
【００４８】
なお上述のように体積率５％以上の再結晶状態から熱間仕上圧延最終パス入口までの温度を２５０〜４００℃、好ましくは２７０〜３７０℃に温度制御するためには、体積率５％以上の再結晶率を確保した後、必要に応じて中間冷却（強制冷却）を行なっても良い。この中間冷却は、例えば熱間圧延で使用されているクーラントで板を強制冷却したり、そのほか水、油、空気などの冷却媒体を用いて板を強制冷却したりすれば良い。なおまた、このように中間冷却を行なう場合、体積率５％以上の再結晶率の確保とそれに続く中間冷却に要する時間は、生産性の観点から１８００秒以内とすることが望ましい。
【００４９】
（７）熱間仕上圧延における上り温度を２００〜３２０℃の範囲内とする。
熱間仕上圧延の上り温度が２００℃未満では表面品質が低下し、また第２相粒子周辺での再結晶核生成が増加して、その後の再結晶でキューブ方位以外の再結晶粒が多くなり、低耳率制御に不利となる。一方上り温度が３２０℃を越えれば、最終板の耳率の変動が大きくなり、最終板の耳率を安定して確実に低耳率に制御することが困難となる。
【００５０】
（８）熱間仕上圧延の上り板厚を１．０〜７．０ｍｍの範囲内とする。
仕上圧延の上がり板厚が１．０ｍｍ未満では、焼鈍後の最終的な冷間圧延での圧延率を充分に確保することが困難となり、最終板の強度不足が生じやすい。一方上り板厚が７．０ｍｍを越えれば、焼鈍後の最終的な冷間圧延において圧延率が高くなり過ぎ、耳率が高くなる傾向を示す。
【００５１】
以上で述べたような（１）〜（８）の条件で、リバーシングミルを用いて熱間圧延を終了させた後、その圧延板に対し、バッチ焼鈍もしくは連続焼鈍により中間焼鈍を施す。この中間焼鈍は、材料を完全に再結晶させて、最終的な冷間圧延後の板の耳率を低くするために必要な工程である。
【００５２】
ここで、中間焼鈍にバッチ焼鈍を適用する場合、平均昇温速度０．１℃／秒以下で２５０〜４５０℃の範囲内の温度に加熱し、その範囲内の温度で０．５時間以上保持し、平均冷却速度０．１℃／秒以下で冷却する。ここで、平均昇温速度および平均冷却速度が０．１℃／秒を越えれば、バッチ焼鈍方式では熱延板コイル全体を均一に加熱もしくは冷却できなくなる問題が生じる。また加熱保持温度が２５０℃未満では完全に再結晶させることが困難となり、一方４５０℃を越える高温では再結晶核が粗大となって、製缶時に肌荒れやフローラインなどの表面欠陥が発生しやすくなる。また加熱保持の時間が０．５時間未満では完全に再結晶させることが困難であり、また熱延板のコイルの全体を均一に加熱することが困難となる。なおバッチ焼鈍の場合の加熱保持時間の上限は特に定めないが、通常は経済性の観点から、２４時間以内とする。
【００５３】
中間焼鈍として連続焼鈍を適用する場合、１〜１００℃／秒の範囲内の平均昇温速度で３３０〜５００℃の範囲内の温度に加熱し、保持なしもしくは１０分以下の保持の後、１〜１００℃／秒の範囲内の平均冷却速度で冷却する。ここで、平均昇温速度、平均冷却速度が１℃／秒未満では、連続焼鈍（ＣＡＬ）方式においては生産性の著しい低下を招き、また１００℃／秒を越える平均昇温速度、平均冷却速度はキューブ方位の再結晶粒の形成に不利となる。また加熱到達温度が３３０℃未満では再結晶が生じにくく、一方５００℃を越える高温ではキューブ方位の再結晶粒の形成に不利となる。さらに３３０〜５００℃に１０分を越えて保持することは、連続焼鈍の生産性を阻害する。
【００５４】
以上のように、バッチ焼鈍もしくは連続焼鈍による中間焼鈍を施した後には、最終板厚としかつ必要な強度を得るために冷間圧延を施す。ここで、最終の冷間圧延率が６０％未満では、加工硬化による強度上昇が少なく、缶胴材用の最終板に必要な強度を得ることが困難である。
【００５５】
冷間圧延後の板は、これを最終板としてそのままＤＩ成形に供しても良いが、冷間圧延板に必要に応じて８０〜２００℃の範囲内の温度で０．５時間以上の最終焼鈍を行なっても良い。この最終焼鈍は、延性の回復による成形性の向上を目的としたものであるが、その温度が８０℃未満では成形性の向上効果が充分に得られず、一方２００℃を越えれば軟化による強度低下が大きくなり、また焼鈍時間が０．５時間未満では成形性向上効果を充分に得ることができない。なお焼鈍時間の上限は特に定めないが、生産性、経済性の点からは１０時間以下が望ましい。
【００５６】
【実施例】
表１に示す金属記号Ａ〜Ｆの各合金について、常法に従ってＤＣ鋳造法によりスラブに鋳塊した。その後、均質化処理を施した後、熱間粗圧延および熱間仕上圧延によって熱間圧延を施した。なお熱間圧延設備としては、粗圧延機、仕上圧延機ともにリバーシングミルを用い、熱間粗圧延速度は７０〜２００ｍ／分、熱間仕上圧延速度は１２０〜４００ｍ／分である。その他の熱間圧延の諸条件を表２の製造番号１〜７に示す。なお熱間粗圧延においては、製造番号６の場合を除き、５％以上の再結晶体積率が確保された段階で冷却媒体として圧延用クーラントを用いて中間冷却を行なった。熱間仕上圧延後の圧延板に対し、表３中に示す条件でバッチ焼鈍もしくは連続焼鈍による中間焼鈍を施し、その後冷間圧延を行なった。冷間圧延後、製造番号５の場合を除いて最終焼鈍を施した。
【００５７】
以上のようにして得られた缶胴用のアルミニウム合金板について、元板の機械的性質（引張強さＴＳ、耐力ＹＳ、伸びＥＬ）および塗装焼付（ベーキング）を想定した２００℃×２０分の熱処理を行なった後の機械的性質を調べた。また元板については、ポンチ径４８ｍｍ、ブランク径９３ｍｍ、クリアランス３０％の条件にてカップ深絞り試験を行なって耳率を調べた。ここで、強度については、塗装焼付（ベーキング）後の耐力として、２７０ＭＰａ以上の値が必要であり、また耳率については、３％を越えれば製缶中のトラブルが発生しやすくなることが知られている。
【００５８】
さらにＤＩ缶成形性評価として、缶切れ性、口拡げ性（フランジ成形性）、シーミング性、および外観欠陥について調べた。ここで、缶切れ性については苛酷なしごき加工を連続１０，０００缶行なったときの缶破断の発生状況を調べ、また口拡げ性については４段ネッキング加工後のフランジ成形性を調べ、さらにシーミング性については４段ネッキング加工後のシーミング加工性を調べ、そしてまた外観欠陥については、ＤＩ缶の缶胴壁の圧延方向に沿ったフローライン状の外観欠陥およびＤＩ方向の縦筋の発生状況を調べ、それぞれ◎〜×で相対評価した。これらの結果を表４に示す。
【００５９】
【表１】

【００６０】
【表２】

【００６１】
【表３】

【００６２】
【表４】

【００６３】
表１〜表４において、製造番号１〜５はいずれもこの発明で規定する成分組成範囲内の合金について、この発明で規定する製造プロセス条件を満足して製造したものであり、この場合は表４に示すように、いずれも耳率が３％を確実に下廻って充分な低耳率を達成でき、かつベーキング後の耐力が２７０ＭＰａ以上で充分な強度を有しており、しかもＤＩ成形性も優れていることが明らかである。
【００６４】
一方製造番号６は、合金の成分組成はこの発明で規定する範囲内であるが、製造プロセス条件がこの発明で規定する範囲から外れたものである。すなわちこの発明の方法の場合、熱間粗圧延工程中において板厚が１５０〜１５ｍｍの範囲内の段階で体積率５％以上の再結晶を生じさせた後、熱間仕上圧延最終パス入口までの温度を４００〜２５０℃の範囲内に維持する必要があるが、製造条件番号６の場合、板厚２０ｍｍで４４％の再結晶体積率を有する板厚から熱間仕上圧延最終パス入口までの間の代表的な温度値である熱間粗圧延上り温度が４１６℃と、この発明で規定する温度範囲（２５０〜４００℃）を越えており、この場合は最終板の耳率が５．６％と高く、缶切れ性が劣っていた。
【００６５】
また製造番号７は、Ｍｇ量が０．４８％とこの発明で規定する合金のＭｇ量下限よりも低く、この場合はベーキング後の強度が低く、また耳率も高く、缶切れ性に劣っていた。
【００６６】
【発明の効果】
前述の実施例からも明らかなように、この発明の方法によれば、ＤＩ缶胴用材料として、缶胴の薄肉化に充分耐え得るような高強度を有すると同時に、ＤＩ成形性、特にフランジ成形性に優れ、しかも深絞り耳率が安定して低いアルミニウム合金板を確実に得ることができる。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a can body for a two-piece aluminum can by DI processing (drawing-ironing processing), that is, a method for producing an Al-Mg-Mn-based aluminum alloy plate used for a DI can body, and particularly has a low deep drawing ear and is coated. The present invention relates to a method for producing an aluminum alloy plate for a DI can body having high strength after baking and excellent moldability during DI processing and formability after baking.
[0002]
[Prior art]
  In general, as a manufacturing process for 2-piece aluminum cans, the can body material is subjected to DI molding by deep drawing and ironing to form a can body shape, then trimmed to a predetermined size, and then degreased and washed. Furthermore, painting and printing are performed and baking (baking) is performed, then necking and flanging are performed on the can body edge, and then seaming processing is performed together with a separately formed can lid (can end). It is normal to go into cans.
[0003]
  Conventionally, a hard plate of JIS 3004 alloy, which is an Al-Mg-Mn alloy, has been widely used as a raw material (can body material) for a DI can thus manufactured. This 3004 alloy is excellent in ironing workability and exhibits relatively good formability even when cold-rolled at a high rolling rate in order to increase strength, and is therefore suitable as a DI can body. Has been.
[0004]
  As a method of manufacturing such a 3004 alloy hard plate for a DI can body, after casting by a DC casting method or the like, the ingot is subjected to homogenization treatment, and further subjected to hot rolling and cold rolling to a predetermined plate. A method is generally used in which the thickness is increased and intermediate annealing is performed before or during the cold rolling in the process.
[0005]
  By the way, it is strongly desired to reduce the thickness of the DI can body mainly for the purpose of reducing the material cost and reducing the weight. In order to reduce the wall thickness in this way, it is indispensable to increase the strength of the material in order to avoid the problem of reduced buckling strength of the can caused by the reduction in thickness.
[0006]
  In addition, the DI can body material is strongly desired not only to have a high strength for thinning as described above, but also to have a low ear rate during DI molding. That is, a low ear rate at the time of DI molding is required from the standpoint of improving the yield at the time of DI molding and preventing can barrel breakage caused by ear can cut of the can barrel. Further, since the balance of strength, flange formability, and ear ratio is affected by how the ear ratio is controlled, the ear ratio control is an extremely important issue for the can body material.
[0007]
  However, in the conventional general can body manufacturing method as described above, there is a limit in suppressing the ear rate, and for example, it was difficult to suppress the ear rate to 3% or less at a drawing ratio of 1.9.
[0008]
  Therefore, a can body manufacturing method for achieving a low ear ratio has already been proposed in, for example, Japanese Patent Application Laid-Open Nos. 5-317914, 9-249932, and 9-268355.
[0009]
[Problems to be solved by the invention]
  In the above-mentioned JP-A-5-317914, a method of performing annealing twice in the middle of cold rolling has been proposed, but when annealing is performed twice in the middle of cold rolling in this way, the final cold rolling is performed. Since the rolling rate cannot be increased, there is a problem that insufficient strength is likely to occur, and there is a problem that the work hardening amount of the material at the time of can making is large and the flange formability is deteriorated.
[0010]
  Japanese Patent Laid-Open No. 9-249932 proposes a method for achieving a low ear rate by strictly regulating the rolling speed, the area reduction rate, and the hot rolling end temperature in the final pass of hot rolling. Although the method is effective to achieve a low ear ratio to some extent, the fluctuation of the ear ratio due to manufacturing chances is still large, and it is insufficient to obtain a low ear ratio reliably and stably.
[0011]
  Furthermore, in JP-A-9-268355, for the case of using a tandem rolling mill for hot finish rolling, a method for achieving a low ear rate by finely regulating the hot finish rolling conditions has been proposed, The method of the present invention is limited to the case where a tandem rolling mill is used for finish rolling, and no consideration is given to the case where a reversing mill is used. Therefore, the reversing mill is applied to hot rolling. It is not effective for controlling the ear rate.
[0012]
  As described above, it is difficult for the conventionally proposed methods to fully satisfy all the requirements for the can body material, and various characteristics necessary as a can body material even when a reversing mill is used. It was difficult to obtain a material that sufficiently satisfied the above.
[0013]
  The present invention has been made against the background of the above circumstances, and is a material that can sufficiently satisfy various requirements desired as a can body material, that is, excellent in strength and flange formability even when thinned, and deep. The basic object of the present invention is to provide a method capable of producing an aluminum alloy plate for a can body with a reliable and stable low ear ratio of the material in the drawing.
[0014]
  The present invention also provides a hot rolling machine.As beiWhen using a Bersing MillInAnother object of the present invention is to provide a method capable of producing an aluminum alloy plate having excellent performance as a can body material as described above.
[0015]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the present inventors have conducted various experiments and examinations, and as a result, the hot roughing process is strictly controlled by strictly regulating the various conditions of the hot rolling process, especially the hot rolling conditions. The inventors have found that the above-mentioned problems can be solved by appropriately controlling recrystallization during rolling and regulating various conditions of finish rolling after recrystallization, and have made the present invention.
[0016]
  Specifically, the manufacturing method of the aluminum alloy plate for can bodies of the invention of claim 1 is Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, SiO 0.05-0.5% containedThe restAfter casting an aluminum alloy consisting of Al and inevitable impurities into a slab, the slab is subjected to a homogenization treatment for 1 hour or more at a temperature in the range of 520 to 630 ° C., andUsing a reversing mill,In slab hot rolling by hot rough rolling and subsequent hot finish rolling,
  (1) The slab thickness at the start of hot rough rolling is 200 mm or more,
  (2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
  (3) From hot rough rolling to hot finish rollingIn each rolling passThe rolling speed is 40 m / min or more,
  (4) Hot rough rolling passes from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mmInThe amount of reductionRespectively15mm or more,
  (5) During hot rough rolling, the temperature from the start of rough rolling to 25% or more and the temperature to the plate thickness within the range of 150 to 15 mm,400 ℃ or higherTemperature andThen, at the stage of the plate thickness within the range of 150 to 15 mm, at least one recrystallization of 5% or more by volume ratio is generated at least once with respect to the whole plate,
  (6) The temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling is in the range of 250 to 400 ° C.WhenAnd
  (7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
  (8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to an average temperature increase rate of 0.1 ° C./second or less to a temperature in the range of 250 to 450 ° C. After performing batch annealing for 5 hours or more, cooling is performed at an average cooling rate of 0.1 ° C./second or less, and then cold rolling is performed at a rolling rate of 60% or more.
[0017]
  Moreover, the manufacturing method of the aluminum alloy plate for can bodies of invention of Claim 2 is Mg0.5-2.0%, Mn0.5-2.0%, Fe0.1-0.7% as raw material aluminum alloy, Si 0.05 to 0.5% and Cu 0.05 to 0.5%, Cr 0.05 to 0.3%, Zn 0.05 to 0.5%, or one or more of them ShiThe restUsing an aluminum alloy whose part is composed of Al and inevitable impurities, homogenization treatment under the same conditions as the process conditions defined in claim 1-hot rolling (rough rolling and finish rolling)-batch annealing-final cold rolling It is manufactured by a process.
[0018]
  Furthermore, the manufacturing method of the aluminum alloy plate for can bodies of the invention of claim 3 uses the same aluminum alloy as the alloy specified in claim 1 as a material alloy, and homogenization treatment-hot rolling (rough rolling and finish rolling). Is carried out under the conditions defined in claim 1 and, as the subsequent annealing, it is heated and maintained at a temperature in the range of 330 to 500 ° C. at an average rate of temperature increase in the range of 1 to 100 ° C./second, or 10 minutes or less. After carrying out continuous annealing of holding, cooling at an average cooling rate within a range of 1 to 100 ° C./second, and then cold rolling at a rolling rate of 60% or more as in the method of claim 1 It is.
[0019]
  And the manufacturing method of the aluminum alloy plate for can bodies of invention of Claim 4 uses the alloy of the same component composition as the component composition prescribed | regulated in Claim 2 as a raw material aluminum alloy, and it manufactures it by the process prescribed | regulated in Claim 3. Is.
[0020]
  On the other hand, the manufacturing method of the aluminum alloy plate for can bodies of the invention of claim 5 is as follows: Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7% Si, 0.05 to 0.5%, 0.005 to 0.20% Ti alone or in combination with 0.0001 to 0.05% B, the balance being Al and inevitable Using an aluminum alloy made of impurities, it is produced by a homogenization treatment-hot rolling (rough rolling and finish rolling) -batch annealing-final cold rolling process similar to the process conditions specified in claim 1. is there.
[0021]
  Moreover, the manufacturing method of the aluminum alloy plate for can bodies of invention of Claim 6 is Mg0.5-2.0%, Mn0.5-2.0%, Fe0.1-0.7% as raw material aluminum alloy, Si 0.05 to 0.5% and Cu 0.05 to 0.5%, Cr 0.05 to 0.3%, Zn 0.05 to 0.5%, or one or more of them And 0.005-0.2 A condition similar to the process condition defined in claim 1, wherein 0% Ti is contained alone or in combination with 0.0001-0.05% B, and the balance is aluminum and an inevitable impurity. Homogenization treatment-Hot rolling (rough rolling and finish rolling)-Batch annealing-Final cold rolling.
[0022]
  Furthermore, the manufacturing method of the aluminum alloy plate for can bodies of the invention of claim 7 uses the same aluminum alloy as the alloy specified in claim 5 as the material alloy, and homogenized under the same conditions as the process conditions specified in claim 3. It is manufactured by a process of processing-hot rolling (rough rolling and finish rolling)-continuous annealing-final cold rolling.
[0023]
  And the manufacturing method of the aluminum alloy plate for can bodies of invention of Claim 8 is manufactured by the process prescribed | regulated in Claim 3, using the alloy of the same component composition as the ingredient composition prescribed | regulated in Claim 6 as raw material aluminum alloy. Is.
[0024]
  Each of the above claims 1 to8In this method, in order to maintain the temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in the hot finish rolling in the range of 250 to 400 ° C., intermediate cooling is performed on the plate during hot rolling. And this is defined in the claims.9It is invention of this.
[0025]
  Further claims 1 to8In this method, after the final cold rolling is performed at a rolling rate of 60% or more, final annealing may be performed by holding at a temperature within a range of 80 to 200 ° C. for 0.5 hours or more. Claimed10It is invention of this.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
  First, the reasons for limiting the component composition of the aluminum alloy used in the method of the present invention will be described.
[0027]
  Mg:
  The addition of Mg is effective in improving the strength by solid solution of Mg itself, and can be expected to improve the strength by increasing the work hardening amount accompanying the solid solution of Mg.₂Strength improvement by aging precipitation of Si can also be expected. Therefore, Mg is an indispensable element for obtaining strength required for a can body material. Further, Mg has an effect of multiplying dislocations at the time of processing, and is therefore effective for making recrystallized grains finer. However, if the amount of Mg is less than 0.5%, the above-mentioned effect is small. On the other hand, if it exceeds 2.0%, high strength can be easily obtained, but the deformation resistance during DI processing increases and the drawability and squeezing property are improved. Make it worse. Therefore, the Mg content is set in the range of 0.5 to 2.0%.
[0028]
  Mn:
  Mn is an effective element that contributes to improvement in strength and formability. In particular, Mn is particularly important for a can body material, which is the intended use of the present invention, because ironing is applied during DI molding. Emulsion-type lubricants are usually used in ironing of aluminum plates, but if there are few Mn-based crystallized products, even if they have the same level of strength, the emulsion-type lubricants alone are not sufficient for lubrication. In addition, appearance defects such as scuffing and seizure called goling may occur. This phenomenon is known to be affected by the size, amount, and type of the crystallized product, and Mn is an indispensable element for forming the crystallized product. If the amount of Mn is less than 0.5%, the effect of solid lubrication by the Mn compound cannot be obtained, while if the amount of Mn exceeds 2.0%, Al₆A primary intermetallic compound of Mn is generated, and the formability is remarkably impaired. Therefore, the amount of Mn is set in the range of 0.5 to 2.0%.
[0029]
  Fe:
  Fe is an element necessary for accelerating crystallization and precipitation of Mn to control the amount of Mn solid solution in the aluminum matrix and the dispersion state of the Mn-based intermetallic compound. In order to obtain an appropriate compound dispersion state, it is necessary to add Fe according to the amount of Mn added. If the amount of Fe is less than 0.1%, it is difficult to obtain a proper compound dispersion state. On the other hand, if the amount of Fe exceeds 0.7%, a primary giant intermetallic compound is likely to be generated with the addition of Mn. Thus, the moldability is remarkably impaired. Therefore, the range of Fe content is set to 0.1 to 0.7%.
[0030]
  Si:
  The addition of Si is Mg₂It contributes to improving the strength of the can body material through age hardening by precipitation of Si-based compounds. Si is an element necessary for generating an Al—Mn—Fe—Si intermetallic compound and controlling the dispersion state of the Mn intermetallic compound. If the amount of Si is less than 0.05%, the above effect cannot be obtained. On the other hand, if it exceeds 0.5%, the material becomes too hard due to age hardening, thereby impairing the moldability. Therefore, the range of Si content is set to 0.05 to 0.5%.
[0031]
  Ti, B:
  In a normal aluminum alloy, a small amount of Ti or Ti and B is added for ingot crystal grain refinement. Also in this invention, a small amount of Ti is used alone or as required. B may be added in combination with B. However, if the amount of Ti is less than 0.005%, the effect cannot be obtained, and if it exceeds 0.20%, a huge Al-Ti intermetallic compound crystallizes and inhibits formability. The amount of Ti was within the range of 0.005 to 0.20%. Moreover, if B is added together with Ti, the effect of refining the ingot crystal grains is improved. However, when B is added together with Ti, the effect is not obtained if the amount of B is less than 0.0001%. If exceeding, Ti—B based coarse particles are mixed to impair the moldability. Therefore, the amount of B in the case of adding B together with Ti is set in the range of 0.0001 to 0.05%.
[0032]
  Cu, Cr, Zn:
  These are all elements that contribute to strength improvement, and one or more selected from these are added as necessary. Each of these elements will be further described.
[0033]
  Cu:
  Cu is in solution in the aluminum matrix during annealing, and contributes to strength improvement using precipitation hardening by depositing as an Al-Cu-Mg-based precipitate during coating baking. If the amount of Cu is less than 0.05%, the effect cannot be obtained. On the other hand, if Cu is added in excess of 0.5%, age hardening can be easily obtained, but it becomes too hard and inhibits formability. Moreover, corrosion resistance also deteriorates. Therefore, the range of Cu content is set to 0.05 to 0.5%.
[0034]
  Cr;
  Cr is also an element effective in improving the strength. However, if it is less than 0.05%, the effect is small, and if it exceeds 0.3%, formability is reduced due to the formation of giant crystals, which is not preferable. Therefore, the range of Cr content is set to 0.05 to 0.3%.
[0035]
  Zn:
  Addition of Zn contributes to strength improvement by aging precipitation of Al—Mg—Zn-based particles. However, if it is less than 0.05%, the effect cannot be obtained, and if it exceeds 0.5%, there is a problem regarding contribution to strength. There is no, but deteriorates the corrosion resistance. Therefore, the range of Zn content is set to 0.05 to 0.5%.
[0036]
  The balance of the above elements may be inevitable impurities with Al.
[0037]
  Next, the manufacturing process in this invention is demonstrated with the effect | action.
[0038]
  First, an aluminum alloy ingot having the above alloy composition is cast by a DC casting method (semi-continuous casting method) or the like according to a conventional method. The ingot is then homogenized to homogenize the ingot segregation and optimize the Mn-based second phase particle size and distribution. If the homogenization treatment temperature is less than 520 ° C, the effect of homogenization is insufficient, while if it exceeds 630 ° C, eutectic melting may occur. If the homogenization treatment is less than 1 hour, homogenization is insufficient. Therefore, it is necessary to carry out the homogenization treatment for 1 hour or more at a temperature in the range of 520 to 630 ° C. The upper limit of the homogenization time is not particularly limited, but it is usually preferably 48 hours or less in consideration of economy.
[0039]
  Hot rolling is performed on the slab subjected to the homogenization treatment. This hot rolling is divided into rough rolling and subsequent finish rolling. In the case of the method of the present invention, a reversing mill (reversible rolling mill) is used for rough rolling and finish rolling.AlsoReversing MLe (Reversible finishing mill; Including reversing worm mill)For cases.
[0040]
  The conditions of this hot rolling process are extremely important in the case of the method of the present invention, and it is important for the control of the ear rate to perform the hot rolling in accordance with the conditions (1) to (8). Therefore, the conditions (1) to (8) will be described in detail.
[0041]
(1) The slab thickness at the start of hot rough rolling is set to 200 mm or more.
  The thickness of the slab during the hot rough rolling is closely related to the condition of the item (4) to be described later, and the amount of rolling in the first half of the hot rough rolling until reaching the plate thickness of 150 mm is secured, and the dislocation is sufficiently accumulated. In order to achieve this, the slab thickness at the start of hot rough rolling needs to be 200 mm or more, and preferably 400 mm or more in order to obtain a sufficient reduction amount. The accumulation of dislocations in the first half of the hot rough rolling will be described in detail in the items (3) and (4).
[0042]
(2) The hot rough rolling start temperature is set within a range of 450 to 580 ° C.
  The starting temperature of hot rough rolling has a strong influence on the material recovery and recrystallization behavior during hot rolling, and in particular the crystal structure of the cube orientation (cube orientation required to lower the deep drawing ear of the final plate) Of crystal grains (hereinafter referred to as “cube band”) plays an important role. If the hot rough rolling start temperature is less than 450 ° C., the amount of cube band formation tends to be insufficient. On the other hand, if hot rough rolling is started at a high temperature exceeding 580 ° C., cube band formation is facilitated, The surface quality is degraded. Therefore, the hot rough rolling start temperature needs to be in the range of 450 to 580 ° C.
[0043]
(3) From hot rough rolling to hot finish rollingIn each rolling passThe rolling speed is set to 40 m / min or more.
  The rolling speed has a strong influence on the recovery and recrystallization behavior of the material, especially the grain and subgrain size, coupled with the rolling temperature and the amount of reduction. If the rolling speed is less than 40 m / min, dislocations are difficult to accumulate, the crystal grains and sub-crystal grains tend to be coarse, the number of cube bands is reduced, and the material's ear rate and mechanical properties are adversely affected. Effect. Moreover, productivity will fall if rolling speed is low. Therefore, the rolling speed needs to be 40 m / min or more, and more preferably 70 m / min or more. The upper limit of the rolling speed is not particularly limited, but is usually preferably 1000 m / min or less in order to obtain good surface quality. Here, the rolling speed means the rolling speed in all passes from each pass of hot rough rolling to each pass of hot finish rolling. Therefore, in the case of the method of the present invention, the rolling speed is set to 40 m / min or more, preferably 70 m / min or more for all passes of hot rough rolling and finish rolling.
[0044]
(4) Hot rough rolling passes from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mmInThe amount of reductionRespectively15 mm or more.
  The slab thickness at the start of hot rough rolling (as described above, 200 mm or more, preferably 400 mm or more) to a plate thickness of 150 mm corresponds to the first half of hot rough rolling, but at this stageeachpathsoThe reduction amount of the material has a strong influence on the recovery and recrystallization behavior of the material, particularly the grain size and subgrain size, in combination with the rolling temperature and rolling speed.Each pass at this stageWhen the rolling amount is less than 15 mm, dislocations are difficult to accumulate, the crystal grains and sub-crystal grains tend to be coarse, and the number of cube buds is small, which adversely affects the ear ratio and mechanical properties of the material. thereOn each passThe amount of rolling is 15 mm or more, preferably 40 mm or more. Although the upper limit of the rolling amount of each pass is not particularly restricted, each pass is usually used to maintain good surface quality.PressureThe lower amount is preferably 100 mm or less.
[0045]
(5) During hot rough rolling, the temperature from the start of rough rolling to 25% or more and the temperature to the plate thickness within the range of 150 to 15 mm,400 ℃ or higherTemperature andAt that stage, recrystallization at a volume ratio of 5% or more is generated at least once for the entire plate.
  In the method of the present invention, during hot rough rolling, recrystallization with a hot rough rolling rate of 25% or more and a plate thickness of 150 to 15 mm in a volume ratio of 5% or more with respect to the whole plate. It is indispensable for the control of the ear rate to generate at least once. That is, the cube band formed by recrystallization at a stage where the hot rough rolling rate is 25% or more and the plate thickness is in the range of 150 to 15 mm is stable and remains on the hot rolled plate, and finally cooled. This is effective in reducing the ear ratio of the final plate after hot rolling. And in order to cause recrystallization with a volume ratio of 5% or more in this way,At the above stageRolling temperature over 400 ° CKeepThere is a need.At that stageIf the rolling temperature is lower than 400 ° C., it is difficult to cause recrystallization with a volume ratio of 5% or more. Therefore, in this invention, the rolling temperature from the start of hot rough rolling during hot rough rolling is 25% or more, and the rolling temperature up to the stage within the range of 150 to 15 mm is 400 ° C. or higher.(Naturally, it is controlled below the hot rough rolling start temperature)Then, at that stage, 5% or more of recrystallization is caused at least once in the volume ratio with respect to the whole plate.
[0046]
  Here, at the stage where the hot rough rolling rate from the start of hot rough rolling is less than 25%, there is little distortion, and recrystallization with a volume rate of 5% or more within a thickness range of 150 to 15 mm can be caused. Have difficulty. In addition, causing recrystallization at a stage thicker than 150 mm itself has no particular adverse effect on the effect of the present invention, but recrystallization occurs at a stage thicker than 150 mm, and the subsequent plate thickness is within a range of 150 to 15 mm. If recrystallization with a volume ratio of 5% or more is not caused at this stage, the effect of controlling the ear ratio cannot be obtained sufficiently. Therefore, the step of causing recrystallization with a volume ratio of 5% or more was set to a step in which the rough rolling rate was 25% or more and the plate thickness was in the range of 150 to 15 mm. Needless to say, recrystallization with a volume ratio of 5% or more may occur twice or more at this stage. Further, the recrystallization generated at this stage requires a volume ratio of 5% or more with respect to the whole plate as described above, but it is more preferable to cause recrystallization with a volume ratio of 15% or more. In addition, at this stage, in order to cause recrystallization with a volume ratio of 5% or more, preferably 15% or more, the rolling temperature is 400 ° C. or more until that stage as described above.KeepAlthough necessary, in order to surely cause recrystallization with a volume ratio of 5% or more, holding at 400 ° C. or more and 1200 seconds or less may be performed in the course of hot rough rolling as necessary.
[0047]
(6) The temperature from the stage in which recrystallization with a volume ratio of 5% or more occurs to the final pass in hot finish rolling is in the range of 250 to 400 ° C.WhenTo do.
  As described in the above section (5), an appropriate dislocation density from the state in which recrystallization having a volume ratio of 5% or more occurs in the stage of the plate thickness of 150 to 15 mm to the final hot rolling end pass entrance. Needs to be accumulated. That is, by introducing dislocations at an appropriate density around the cube band structure formed at a stage where the plate thickness is in the range of 150 to 15 mm, self-annealing with self-held heat in the state of hot rolling up, In the subsequent batch annealing or continuous annealing, the growth of the crystal structure in the cube orientation can be aimed at, which is advantageous in restricting the ear ratio of the final plate after the final cold rolling to be low. Here, when the rolling temperature is lower than 250 ° C. between the recrystallized state with a volume ratio of 5% or more and the final pass of hot finish rolling, the surface quality deteriorates and recrystallization nucleation around coarse particles occurs. The number increases, and subsequent recrystallization increases the number of recrystallized grains other than the cube orientation, which is disadvantageous for low ear rate control. On the other hand, when the temperature in the meantime exceeds 400 ° C., recovery and recrystallization easily proceed, and it becomes difficult to introduce sufficient dislocations. Accordingly, it is necessary to control the temperature from the recrystallized state with a volume ratio of 5% or more to the hot finish rolling final pass entrance within the range of 250 to 400 ° C, and even within this range, the temperature is particularly within the range of 270 to 370 ° C. Is preferred.
[0048]
  In order to control the temperature from the recrystallized state having a volume ratio of 5% or more to the final hot rolling final pass entrance as described above at 250 to 400 ° C, preferably 270 to 370 ° C, the volume ratio is 5% or more. After securing the recrystallization rate, intermediate cooling (forced cooling) may be performed as necessary. For this intermediate cooling, for example, the plate may be forcibly cooled with a coolant used in hot rolling, or the plate may be forcibly cooled using a cooling medium such as water, oil, or air. In addition, when the intermediate cooling is performed in this way, it is desirable that the time required for securing the recrystallization rate of 5% or more and the subsequent intermediate cooling is within 1800 seconds from the viewpoint of productivity.
[0049]
(7) The ascending temperature in the hot finish rolling is set in the range of 200 to 320 ° C.
  If the ascending temperature of hot finish rolling is less than 200 ° C, the surface quality deteriorates, and recrystallization nucleation increases around the second phase particles, and subsequent recrystallization increases the number of recrystallized grains other than the cube orientation. It is disadvantageous for low ear rate control. On the other hand, when the rising temperature exceeds 320 ° C., the fluctuation of the ear rate of the final plate increases, and it becomes difficult to stably control the ear rate of the final plate to a low ear rate.
[0050]
(8) The finishing plate thickness of hot finish rolling is set within a range of 1.0 to 7.0 mm.
  If the finishing plate thickness of finish rolling is less than 1.0 mm, it becomes difficult to ensure a sufficient rolling rate in the final cold rolling after annealing, and the strength of the final plate is likely to be insufficient. On the other hand, if the ascending plate thickness exceeds 7.0 mm, the rolling rate becomes too high in the final cold rolling after annealing, and the ear rate tends to increase.
[0051]
  Under the conditions (1) to (8) as described aboveUsing a reversing millAfter finishing the hot rolling, intermediate annealing is performed on the rolled sheet by batch annealing or continuous annealing. This intermediate annealing is a process necessary for completely recrystallizing the material and lowering the ear ratio of the plate after the final cold rolling.
[0052]
  Here, when batch annealing is applied to the intermediate annealing, it is heated to a temperature in the range of 250 to 450 ° C. at an average heating rate of 0.1 ° C./second or less, and held at the temperature in the range for 0.5 hour or more. And cooling at an average cooling rate of 0.1 ° C./second or less. Here, if the average heating rate and the average cooling rate exceed 0.1 ° C./second, there arises a problem that the whole hot rolled plate coil cannot be uniformly heated or cooled by the batch annealing method. Also, if the heating and holding temperature is less than 250 ° C, it is difficult to completely recrystallize. On the other hand, if the temperature exceeds 450 ° C, the recrystallization nuclei are coarse, and surface defects such as rough skin and flow lines are likely to occur during canning. Become. Further, if the heating and holding time is less than 0.5 hours, it is difficult to completely recrystallize, and it becomes difficult to uniformly heat the entire coil of the hot rolled sheet. The upper limit of the heating and holding time in the case of batch annealing is not particularly defined, but is usually within 24 hours from the viewpoint of economy.
[0053]
  When continuous annealing is applied as intermediate annealing, it is heated to a temperature in the range of 330 to 500 ° C. at an average temperature increase rate in the range of 1 to 100 ° C./second, and after holding for 10 minutes or less, 1 Cool at an average cooling rate in the range of ~ 100 ° C / sec. Here, if the average heating rate and the average cooling rate are less than 1 ° C./second, the productivity decreases in the continuous annealing (CAL) method, and the average heating rate and the average cooling rate exceed 100 ° C./second. Is disadvantageous for the formation of recrystallized grains with cube orientation. Further, when the temperature reached by heating is less than 330 ° C., recrystallization hardly occurs, while when the temperature exceeds 500 ° C., it is disadvantageous for the formation of recrystallized grains having a cube orientation. Furthermore, holding at 330 to 500 ° C. for more than 10 minutes inhibits the productivity of continuous annealing.
[0054]
  As described above, after performing intermediate annealing by batch annealing or continuous annealing, cold rolling is performed in order to obtain a final thickness and necessary strength. Here, when the final cold rolling reduction is less than 60%, the strength increase due to work hardening is small, and it is difficult to obtain the strength necessary for the final plate for the can body material.
[0055]
  The cold-rolled plate may be used as it is as a final plate for DI molding, but the cold-rolled plate may be subjected to final annealing at a temperature in the range of 80 to 200 ° C. for 0.5 hour or longer as necessary. May be performed. This final annealing is aimed at improving the formability by recovering the ductility, but if the temperature is less than 80 ° C, the effect of improving the formability is not sufficiently obtained, while if it exceeds 200 ° C, the strength due to softening is obtained. If the decrease is large and the annealing time is less than 0.5 hours, the effect of improving the formability cannot be obtained sufficiently. The upper limit of the annealing time is not particularly defined, but is preferably 10 hours or less from the viewpoint of productivity and economy.
[0056]
【Example】
  Each alloy of metal symbols A to F shown in Table 1 was cast into a slab by a DC casting method according to a conventional method. Then, after performing homogenization treatment, hot rolling was performed by hot rough rolling and hot finish rolling. As the hot rolling equipment, a roughing mill and a finishing mill are both reversing mills, the hot rough rolling speed is 70 to 200 m / min, and the hot finish rolling speed is 120 to 400 m / min. Other conditions of hot rolling are shown in production numbers 1 to 7 in Table 2. In the hot rough rolling, except for the case of production number 6, intermediate cooling was performed using a rolling coolant as a cooling medium when a recrystallization volume ratio of 5% or more was secured. The rolled plate after hot finish rolling was subjected to intermediate annealing by batch annealing or continuous annealing under the conditions shown in Table 3, and then cold rolling was performed. After the cold rolling, final annealing was performed except for the case of production number 5.
[0057]
  About the aluminum alloy plate for can bodies obtained as described above, the mechanical properties (tensile strength TS, proof stress YS, elongation EL) and coating baking (baking) of the base plate were assumed at 200 ° C. for 20 minutes. The mechanical properties after the heat treatment were examined. The base plate was subjected to a cup deep drawing test under the conditions of a punch diameter of 48 mm, a blank diameter of 93 mm, and a clearance of 30%, and the ear rate was examined. Here, as for the strength, a value of 270 MPa or more is required as the proof strength after baking (baking), and when the ear rate exceeds 3%, it is known that troubles during can making are likely to occur. It has been.
[0058]
  Further, as a DI can moldability evaluation, can tearability, mouth spreadability (flange moldability), seamability, and appearance defects were examined. Here, regarding can breakability, the state of occurrence of can breakage after continuous 10,000 cans without harsh ironing was investigated, and regarding the spreadability, flange formability after four-stage necking was examined, and seaming was further performed. For seamability, the seaming workability after four-stage necking was investigated, and for appearance defects, the appearance of flow line-like appearance defects along the rolling direction of the can body wall of the DI can and vertical stripes in the DI direction were observed. The relative evaluation was made with 相対 to ×. These results are shown in Table 4.
[0059]
[Table 1]

[0060]
[Table 2]

[0061]
[Table 3]

[0062]
[Table 4]

[0063]
  In Tables 1 to 4, production numbers 1 to 5 are all manufactured within the component composition range defined in the present invention while satisfying the production process conditions defined in the present invention. As shown in Fig. 4, the ear rate is surely below 3% and a sufficiently low ear rate can be achieved, and the strength after baking is 270 MPa or more, and the DI moldability is also good. It is clear that it is excellent.
[0064]
  On the other hand, in the production number 6, the alloy component composition is within the range specified in the present invention, but the manufacturing process condition is out of the range defined in the present invention. That is, in the case of the method of the present invention, during the hot rough rolling process, after the recrystallization with a volume ratio of 5% or more is caused in the stage where the plate thickness is in the range of 150 to 15 mm, the hot finish rolling until the final pass entrance. Although it is necessary to maintain the temperature within the range of 400 to 250 ° C., in the case of production condition number 6, from the plate thickness having a recrystallization volume ratio of 44% at a plate thickness of 20 mm to the hot finish rolling final pass entrance The temperature of hot rough rolling as a typical temperature value is 416 ° C., which exceeds the temperature range (250 to 400 ° C.) defined in the present invention. In this case, the final plate has an ear ratio of 5.6%. It was high and the cannedness was inferior.
[0065]
  Production No. 7 has an Mg content of 0.48%, which is lower than the lower limit of the Mg content of the alloy defined in the present invention. In this case, the strength after baking is low, the ear rate is high, and the can tearability is poor. It was.
[0066]
【The invention's effect】
  As is clear from the above-described embodiments, according to the method of the present invention, the DI can barrel material has high strength enough to withstand the thinning of the can barrel, and at the same time, DI moldability, particularly flange. It is possible to reliably obtain an aluminum alloy plate that is excellent in formability and has a stable and low deep drawing ratio.

Claims

Mg0.5～2.0% (wt%, hereinafter the same), Mn0.5~2.0%, Fe0.1~0.7%, containing Si0.05～0.5%, the remaining portion of Al After casting an aluminum alloy composed of unavoidable impurities into a slab, the slab is subjected to a homogenization treatment for 1 hour or more at a temperature in the range of 520 to 630 ° C., and the slab is heated using a reversing mill. In hot rolling by hot rough rolling and subsequent hot finish rolling,
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) a reduction ratio in rough hot rolling each path from rough hot rolling starting slab thickness to reach the plate thickness 150mm and respectively 15mm or more,
(5) during rough hot rolling, the temperatures up to the thickness of the steps within the range the rolling rate and the 150~15mm 25% or more from the rough rolling start, and a temperature above 400 ° C., the 150 Causing at least one recrystallization of 5% or more by volume with respect to the whole plate at the stage of the plate thickness within a range of ˜15 mm,
(6) the temperature of the stage of the more than 5% of recrystallized volume fraction up to the final pass in the hot finish rolling in the range of 250 to 400 ° C.,
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to an average temperature increase rate of 0.1 ° C./second or less to a temperature in the range of 250 to 450 ° C. For can body characterized by performing batch annealing for 5 hours or more, cooling at an average cooling rate of 0.1 ° C./second or less, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, and Cu 0.05-0.5%, Cr0 .05～0.3%, contain one or two or more of Zn0.05～0.5%, after the aluminum alloy remaining portion is made of Al and unavoidable impurities was cast into a slab, the slab In the case of subjecting the slab to hot rolling by hot rough rolling and subsequent hot finish rolling using a reversing mill , the homogenization treatment is performed at a temperature in the range of 520 to 630 ° C. for 1 hour or more.
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) a reduction ratio in rough hot rolling each path from rough hot rolling starting slab thickness to reach the plate thickness 150mm and respectively 15mm or more,
(5) during rough hot rolling, the temperatures up to the thickness of the steps within the range the rolling rate and the 150~15mm 25% or more from the rough rolling start, and a temperature above 400 ° C., the 150 Causing at least one recrystallization of 5% or more by volume with respect to the whole plate at the stage of the plate thickness within a range of ˜15 mm,
(6) the temperature of the stage of the more than 5% of recrystallized volume fraction up to the final pass in the hot finish rolling in the range of 250 to 400 ° C.,
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to an average temperature increase rate of 0.1 ° C./second or less to a temperature in the range of 250 to 450 ° C. For can body characterized by performing batch annealing for 5 hours or more, cooling at an average cooling rate of 0.1 ° C./second or less, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate.

Mg0.5~2.0%, Mn0.5~2.0%, Fe0.1~0.7% , containing Si0.05~0.5%, aluminum remaining portion is made of Al and unavoidable impurities After the alloy is cast into a slab, the slab is subjected to a homogenization treatment for 1 hour or more at a temperature in the range of 520 to 630 ° C., and further using a reversing mill, the slab is subjected to hot rough rolling and subsequent heat rolling. In hot rolling by intermediate finish rolling,
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) a reduction ratio in rough hot rolling each path from rough hot rolling starting slab thickness to reach the plate thickness 150mm and respectively 15mm or more,
(5) during rough hot rolling, the temperatures up to the thickness of the steps within the range the rolling rate and the 150~15mm 25% or more from the rough rolling start, and a temperature above 400 ° C., the 150 Causing at least one recrystallization of 5% or more by volume with respect to the whole plate at the stage of the plate thickness within a range of ˜15 mm,
(6) the temperature of the stage of the more than 5% of recrystallized volume fraction up to the final pass in the hot finish rolling in the range of 250 to 400 ° C.,
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to a temperature in the range of 330 to 500 ° C. at an average temperature increase rate in the range of 1 to 100 ° C./second. After performing continuous annealing without holding or holding for 10 minutes or less, cooling at an average cooling rate within a range of 1 to 100 ° C./second, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate for a can body.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, and Cu 0.05-0.5%, Cr0 .05～0.3%, contain one or two or more of Zn0.05～0.5%, after the aluminum alloy remaining portion is made of Al and unavoidable impurities was cast into a slab, the slab In the case of subjecting the slab to hot rolling by hot rough rolling and subsequent hot finish rolling using a reversing mill , the homogenization treatment is performed at a temperature in the range of 520 to 630 ° C. for 1 hour or more.
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) a reduction ratio in rough hot rolling each path from rough hot rolling starting slab thickness to reach the plate thickness 150mm and respectively 15mm or more,
(5) during rough hot rolling, the temperatures up to the thickness of the steps within the range the rolling rate and the 150~15mm 25% or more from the rough rolling start, and a temperature above 400 ° C., the 150 Causing at least one recrystallization of 5% or more by volume with respect to the whole plate at the stage of the plate thickness within a range of ˜15 mm,
(6) the temperature of the stage of the more than 5% of recrystallized volume fraction up to the final pass in the hot finish rolling in the range of 250 to 400 ° C.,
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to a temperature in the range of 330 to 500 ° C. at an average temperature increase rate in the range of 1 to 100 ° C./second. After performing continuous annealing without holding or holding for 10 minutes or less, cooling at an average cooling rate within a range of 1 to 100 ° C./second, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate for a can body.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, further 0.005-0.20% Ti In an amount of 520 to 630 ° C. with respect to the slab after casting an aluminum alloy containing Al and unavoidable impurities into the slab. When the slab is hot-rolled by hot rough rolling and subsequent hot finish rolling using a reversing mill, subjected to a homogenization treatment for 1 hour or more at a temperature,
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) The amount of reduction in each pass of hot rough rolling from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mm is 15 mm or more,
(5) During hot rough rolling, the rolling rate from the start of rough rolling is 25% or more, and the temperature up to the plate thickness within the range of 150 to 15 mm is set to a temperature of 400 ° C. or more, and the temperature is 150 to 15 mm. In the stage of the plate thickness within the range of 5% or more, recrystallization of 5% or more by volume ratio with respect to the whole plate is caused at least once,
(6) The temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling is in the range of 250 to 400 ° C.
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to an average temperature increase rate of 0.1 ° C./second or less to a temperature in the range of 250 to 450 ° C. For can body characterized by performing batch annealing for 5 hours or more, cooling at an average cooling rate of 0.1 ° C./second or less, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, and Cu 0.05-0.5%, Cr0 0.05-0.3%, Zn 0.05-0.5%, or one or more of 0.005 to 0.20% Ti alone or 0.0001-0. After casting an aluminum alloy containing 05% B in combination with the balance consisting of Al and inevitable impurities into a slab, the slab is subjected to a homogenization treatment at a temperature in the range of 520 to 630 ° C. for 1 hour or longer. In addition, using a reversing mill, the hot slab is hot rolled by hot rough rolling followed by hot finish rolling.
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) The amount of reduction in each pass of hot rough rolling from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mm is 15 mm or more,
(5) During hot rough rolling, the rolling rate from the start of rough rolling is 25% or more, and the temperature up to the plate thickness within the range of 150 to 15 mm is set to a temperature of 400 ° C. or more, and the temperature is 150 to 15 mm. In the stage of the plate thickness within the range of 5% or more, recrystallization of 5% or more by volume ratio with respect to the whole plate is caused at least once,
(6) The temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling is in the range of 250 to 400 ° C.
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to an average temperature increase rate of 0.1 ° C./second or less to a temperature in the range of 250 to 450 ° C. For can body characterized by performing batch annealing for 5 hours or more, cooling at an average cooling rate of 0.1 ° C./second or less, and then performing cold rolling at a rolling rate of 60% or more . A method for producing an aluminum alloy plate.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, further 0.005-0.20% Ti In an amount of 520 to 630 ° C. with respect to the slab after casting an aluminum alloy containing Al and unavoidable impurities into the slab. When the slab is hot-rolled by hot rough rolling and subsequent hot finish rolling using a reversing mill, subjected to a homogenization treatment for 1 hour or more at a temperature,
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) The amount of reduction in each pass of hot rough rolling from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mm is 15 mm or more,
(5) During hot rough rolling, the rolling rate from the start of rough rolling is 25% or more, and the temperature up to the plate thickness within the range of 150 to 15 mm is set to a temperature of 400 ° C. or more, and the temperature is 150 to 15 mm. In the stage of the plate thickness within the range of 5% or more, recrystallization of 5% or more by volume ratio with respect to the whole plate is caused at least once,
(6) The temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling is in the range of 250 to 400 ° C.
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to a temperature in the range of 330 to 500 ° C. at an average temperature increase rate in the range of 1 to 100 ° C./second. After performing continuous annealing without holding or holding for 10 minutes or less, cooling at an average cooling rate within a range of 1 to 100 ° C./second, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate for a can body.

Mg 0.5-2.0%, Mn 0.5-2.0%, Fe 0.1-0.7%, Si 0.05-0.5%, and Cu 0.05-0.5%, Cr0 0.05-0.3%, Zn 0.05-0.5%, or one or more of 0.005 to 0.20% Ti alone or 0.0001-0. After casting an aluminum alloy containing 05% B in combination with the balance consisting of Al and inevitable impurities into a slab, the slab is subjected to a homogenization treatment at a temperature in the range of 520 to 630 ° C. for 1 hour or longer. In addition, using a reversing mill, the hot slab is hot rolled by hot rough rolling followed by hot finish rolling.
(1) The slab thickness at the start of hot rough rolling is 200 mm or more,
(2) The hot rough rolling start temperature is in the range of 450 to 580 ° C,
(3) The rolling speed in each rolling pass from hot rough rolling to hot finish rolling is 40 m / min or more,
(4) The amount of reduction in each pass of hot rough rolling from the slab thickness at the start of hot rough rolling to the plate thickness of 150 mm is 15 mm or more,
(5) During hot rough rolling, the rolling rate from the start of rough rolling is 25% or more, and the temperature up to the plate thickness within the range of 150 to 15 mm is set to a temperature of 400 ° C. or more, and the temperature is 150 to 15 mm. In the stage of the plate thickness within the range of 5% or more, recrystallization of 5% or more by volume ratio with respect to the whole plate is caused at least once,
(6) The temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling is in the range of 250 to 400 ° C.
(7) Further, the ascending temperature in the hot finish rolling is in the range of 200 to 320 ° C.,
(8) And ascending plate thickness in the hot finish rolling is in the range of 1.0 to 7.0 mm,
The hot-rolled sheet obtained under the above conditions (1) to (8) is heated to a temperature in the range of 330 to 500 ° C. at an average temperature increase rate in the range of 1 to 100 ° C./second. After performing continuous annealing without holding or holding for 10 minutes or less, cooling at an average cooling rate within a range of 1 to 100 ° C./second, and then performing cold rolling at a rolling rate of 60% or more. A method for producing an aluminum alloy plate for a can body.

In the manufacturing method of the aluminum alloy plate for can bodies according to any one of claims 1 to 8 ,
In order to maintain the temperature from the stage of the recrystallization volume ratio of 5% or more to the final pass in hot finish rolling within the range of 250 to 400 ° C., intermediate cooling is performed on the plate in the middle of hot rolling A method for producing an aluminum alloy plate for a can body.

In the manufacturing method of the aluminum alloy plate for can bodies according to any one of claims 1 to 8 ,
An aluminum alloy sheet for a can body, characterized in that after cold rolling at a rolling rate of 60% or more, final annealing is further performed at a temperature in the range of 80 to 200 ° C. for 0.5 hours or more. Production method.