JP3682683B2 - Method for producing steel plate for two-piece can with excellent in-plane anisotropic uniformity in coil - Google Patents
Method for producing steel plate for two-piece can with excellent in-plane anisotropic uniformity in coil Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description
【０００１】
【発明の属する技術分野】
この発明は、面内異方性のコイル内均一性に優れた２ピース缶用鋼板の製造方法に関するものである。
【０００２】
【従来の技術】
鋼板の表面に錫めっき処理が施された錫めっき鋼板または鋼板の表面に電解クロム酸処理が施されたティンフリースチール（ＴＦＳ）のような缶用鋼板は、食缶や飲料缶用鋼板として多用されている。これらの食缶や飲料缶は、その製缶方法の相違から、３ピース缶と２ピース缶とに分類されるが、近年飲料缶を中心として、缶体の軽量化、製缶工程の省略、素材および製造コストの低減等の観点より、３ピース缶から２ピース缶への移行、更には、缶体の薄肉化が進められている。
【０００３】
食缶、飲料缶用の２ピース缶には、絞りおよび再絞り加工によって製造されるＤＲＤ缶(Drawn and redrawn can) 、缶胴部の薄肉化を伴う多段の絞り加工によって製造されるＤＴＲ缶(Drawn-thin-redrawn can)および絞り加工後にしごき加工が施されるＤＩ缶(Drawn and wall ironed can) 等があるが、その何れの場合においても、製缶に際して円盤状のブランク板から絞り加工によってカップ状の缶体を成形するか、または、カップ状の缶体から再絞り加工によって更に径が小さく深さの深いカップ状の缶体を成形する工程を含んでいる。
【０００４】
このような２ピース缶製缶時の際の絞り加工時に、鋼板の加工性の面内異方性に起因して、しばしば、缶端部の高さまたはフランジ部の幅が円周方向に沿って不均一になるいわゆる耳が発生する。この耳は、缶端部のネッキング加工前にトリムして除去されるが、耳が大きい場合にはトリム代が大きくなり、材料歩留りを低下させる。
【０００５】
更に、耳は、円周方向に沿った板厚分布の変動をもたらし、後工程のネッキング加工の際におけるネックしわの発生原因になるのみならず、成形時にパンチから缶体を抜き取る際のパンチ抜け不良の発生原因にもなって、材料歩留りおよび品質の低下をもたらしている。
【０００６】
このようなことから、２ピース缶用鋼板に対しては、製缶時における耳発生の小さい即ち面内異方性の小さい鋼板が求められており、特に、ＤＩ缶用鋼板およびＤＴＲ缶用鋼板に対しては、近年求められている缶体の軽量化、製造コスト低減の観点から、薄ゲージであってしかも材料歩留りの向上が可能な、面内異方性が一段と小さく、且つ、面内異方性がコイルの全長および全幅にわたって均一な鋼板が強く望まれている。
【０００７】
面内異方性の小さい２ピース缶用鋼板の製造方法としては、例えば、特開平９−２４１７５６号公報に、冷延前の結晶粒径を３０μｍ以上に制御し、イヤリングを低減する方法（以下、先行技術１という）が開示されている。
【０００８】
一方、板幅方向に均一な材質を有する缶用鋼板の製造方法として、特開平１０−４６２４３号公報には、粗圧延されたシートバーの両端部を加熱昇温することにより、圧延終了温度が鋼帯の全幅にわたってＡｒ3 変態点未満、（Ａｒ3 変態点−１００℃）以上となるように熱間仕上圧延し、次いで、冷間圧延、焼鈍および調質圧延を行う方法（以下、先行技術２という）が開示されている。
【０００９】
【発明が解決しようとする課題】
しかしながら、先行技術１には、コイルの長手方向および幅方向の不均一性を抑制する、換言すれは、上記コイル長手方向および幅方向の均一性を従来以上に向上させるという技術思想は含まれていない。従って、コイルの長手方向および幅方向端部のイヤリング性即ち面内異方性の低下を避けることはできず、コイル内のブランキング位置による面内異方性のバラツキが大になって、材料歩留りの低下をもたらすという問題は解決されていない。
【００１０】
先行技術２は、熱延仕上温度をＡｒ3 変態点未満にする技術であり、本発明の意図する技術とは本質的に異なる技術であるが、このような技術を用いたとしても、鋼板幅方向の材質均一性は向上するものの、鋼板長手方向の均一性に関しては、必ずしも十分であるとは言い難い。
【００１１】
即ち、鋼板長手方向の均一性を向上させるためには、更に、シートバーを仕上圧延前に巻取り、その先端と後端とを逆転させて、先行するシートバーと接合することが必要であり、熱延工程の大幅な改造および付帯設備の設置が必要となって、製造コストの大幅な増大をもたらす。更に、このような技術を用いても、鋼板長手方向の均一性に関しては、２ピース缶用鋼板に求められている現在の厳しい要求に十分に応えることは難しく、一層の改善を図る必要がある。
【００１２】
従って、この発明の目的は、上述した従来技術の問題点を解決し、現在の要求に十分に応え得る、面内異方性のコイル内均一性に優れた２ピース缶用鋼板の製造方法を提供することにある。
【００１３】
【課題を解決するための手段】
本発明者等は、上述した問題を解決し、面内異方性のコイル内均一性に優れた２ピース缶用鋼板の製造方法を開発すべく鋭意研究を重ねた。
【００１４】
２ピース缶用鋼板のゲージダウンが進むに伴って、熱延鋼板の仕上板厚も薄くなってきているが、熱延鋼板の薄手化により、熱間圧延中の放熱が大きくなり、特に鋼板先端部の温度低下が大きく、仕上圧延出側温度（ＦＴ）をＡｒ3 変態点以上とすることが困難になっている。そのために、コイル長手方向中央部では良好な面内異方性を維持することができても、鋼板先端部では面内異方性が大きく劣化する問題が生ずる。
【００１５】
本発明者らは、極薄の２ピース缶用鋼板の面内異方性の均一性の低下、特に、鋼帯長手方向先端部での面内異方性の劣化は、熱間仕上圧延時の仕上圧延出側温度（ＦＴ）がＡｒ3 変態点未満まで低下してしまうためであるとの考えに基づき、これを回避するための方法について検討を行った。その結果、仕上圧延前の粗バーの幅方向全体を誘導加熱装置によって加熱し、仕上圧延入側温度を調整することがもっとも効果的且つ経済的であることを見出した。
【００１６】
図１は、０．０４wt.%のＣを含有する化学成分組成の連続鋳造スラブを使用し、熱延仕上板厚を１．６ｍｍとした場合の仕上圧延出側温度（ＦＴ）に対する粗バーの幅方向全体の誘導加熱装置装置による加熱（粗バー全体加熱）効果を調べた結果を示す図であり、図２は、イヤリング率のコイル内均一性に対する粗バー全体加熱効果を示す図である。
【００１７】
面内異方性は、熱間圧延後、酸洗、冷間圧延、焼鈍、調質圧延を行い、板厚０．１７ｍｍに仕上げた鋼板のイヤリング率を測定し評価した。イヤリング率は、絞り比１．８で深絞り成形したときの耳高さを測定し、耳の最大値と最小値との差を耳全周の平均値で割った百分率で表した。
【００１８】
図１および図２から明らかなように、粗バー加熱を行わなかった場合は、熱延鋼帯の先端部（図のＴ部）における仕上圧延出側温度（ＦＴ）の低下が大きくＡｒ3 変態点未満となり、イヤリング率が劣化し、鋼板幅方向および長手方向のイヤリング率の均一性が非常に悪い。エッジヒーターによって粗バーのエッジ部近傍のみを加熱した場合には、エッジ部におけるＦＴの低下は抑制され、エッジ部のイヤリング率は若干改善されるが、鋼板長手方向先端部については、その幅中央部、エッジ部共にＦＴはＡｒ3 変態点未満となり、イヤリング率の劣化を回避することができない。
【００１９】
これに対して、粗バー全体を加熱した場合には、長手方向先端部のエッジ部を含めた全長および全幅にわたり、仕上圧延出側温度（ＦＴ）をＡｒ3 変態点以上で、且つ、均一な温度とすることができ、先端部またはエッジ部でのイヤリング率の劣化も認められず、面内異方性のコイル内均一性は非常に良好になる。
【００２０】
このように、面内異方性のコイル内均一性に優れた２ピース缶用鋼板を製造するためには、熱間圧延工程の仕上圧延出側温度（ＦＴ）を最適範囲に制御することが重要であり、そのためには、粗バーの幅方向全体を加熱し、仕上圧延入側温度を調整することが有効であることがわかった。
【００２１】
この発明は、上記知見に基づいてなされたものであって、本願の請求項１に記載の発明は、Ｃ：０．０１〜０．１０wt.%、Ｓｉ：０．１ wt.% 以下、Ｍｎ：０．１〜１．０ wt.% 、Ｐ：０．０２ wt.% 以下、Ｓ：０．０２ wt.% 以下、ｓｏｌ．Ａｌ：０．０２〜０．１５ wt.% 、Ｎ：０．０１ wt.% 以下、残部Ｆｅおよび不可避的不純物からなる化学成分組成を有する連続鋳造薄スラブまたは連続鋳造スラブを粗圧延した粗バーを、鋼帯に熱間仕上圧延するに際し、熱間仕上圧延機の入側に配置された誘導加熱装置により、前記薄スラブまたは前記粗バーの幅方向全体を加熱して、その仕上圧延入側温度を調整し、仕上圧延出側温度が、鋼帯の先端部から後端部に至るまで全長にわたりＡｒ3 変態点以上、Ａｒ3 ＋４０℃以下の温度となり、そして、仕上板厚が２．３mm以下となるように前記薄スラブまたは前記粗バーを熱間仕上圧延して熱延鋼帯を調製し、得られた熱延鋼帯をコイルに巻取り次いで酸洗した後、冷間圧延し、得られた冷延鋼帯に対し、焼鈍し次いで調質圧延または二次圧延を施して、板厚０．２５mm以下の鋼帯となし、次いで、前記鋼帯に対し表面処理を施すことに特徴を有するものである。
【００２２】
請求項２に記載の発明は、Ｃ：０．０１〜０．１０wt.%、Ｓｉ：０．１wt.%以下、Ｍｎ：０．１〜１．０wt.%、Ｐ：０．０２wt.%以下、Ｓ：０．０２wt.%以下、ｓｏｌ．Ａｌ：０．０２〜０．１５wt.%、Ｎ：０．０１wt.%以下、残部Ｆｅおよび不可避的不純物からなる化学成分組成を有する連続鋳造薄スラブまたは連続鋳造スラブを粗圧延した粗バーを、鋼帯に熱間仕上圧延するに際し、熱間仕上圧延機の入側に配置された誘導加熱装置により、前記薄スラブまたは粗バーの幅方向全体を加熱して、その仕上圧延入側温度を調整し、仕上圧延出側温度が、鋼帯の先端部から後端部に至るまで全長にわたりＡｒ3 変態点以上、Ａｒ3 ＋４０℃以下の温度となり、そして、仕上板厚が２．３mm以下となるように前記薄スラブまたは前記粗バーを熱間仕上圧延して熱延鋼帯を調製し、得られた熱延鋼帯を５４０〜７００℃の温度でコイルに巻取り次いで酸洗した後、８０〜９５％の圧下率で冷間圧延し、得られた冷延鋼帯を焼鈍し次いで調質圧延または二次圧延を施して、板厚０．２５mm以下の鋼帯となし、次いで、前記鋼帯に対し表面処理を施すことに特徴を有するものである。
【００２３】
請求項３に記載の発明は、前記連続鋳造薄スラブまたは粗バーが、０．０００３〜０．００３wt.%のＢを更に含有していることに特徴を有するものである。
請求項４に記載の発明は、前記熱延鋼帯の、先端部の仕上圧延出側温度と後端部の仕上圧延出側温度の差が２０℃以下であることに特徴を有するものである。
【００２４】
請求項５に記載の発明は、前記連続鋳造薄スラブまたは前記粗バーの少なくとも長手方向先端部を、その幅方向全体にわたり加熱し、前記先端部の表面温度を４５℃以上昇温させることに特徴を有するものである。
【００２５】
請求項６に記載の発明は、粗圧延機と誘導加熱装置との間、または、誘導加熱装置と仕上圧延機との間にエッジヒータを配置し、配置されたエッジヒータによって、粗バーのエッジ部のみを加熱することに特徴を有するものである。
【００２６】
【発明の実施の形態】
この発明の方法において、鋼の化学成分組成を、上述したように限定した理由について以下に述べる。
【００２７】
Ｃ：Ｃ含有量が０．０１wt.%未満の場合には、熱延板組織が粗粒化および混粒化しやすくなり、熱延段階での組織の均一性が低下すると共に、焼鈍後の粒径も大きくなりやすく、製缶時に肌荒れが発生しやすくなる。一方、Ｃ含有量が０．１０wt.%を超えると、フェライト粒内の固溶Ｃ量、粒界に偏析するＣ量および炭化物の量が増加するため、深絞り性が劣化すると共に、面内異方性も劣化する。従って、この発明においては、Ｃ含有量を０．０１〜０．１０wt.%の範囲内に限定することが基本である。より好ましいＣ含有量は、０．０１５〜０．０６wt.%の範囲内である。
【００２８】
Ｓｉ：Ｓｉは、これを意図的に添加しない場合でも、不純物成分として鋼中に残留し、鋼板を脆化させ耐食性を劣化させる元素である。また、ＴＦＳの下地鋼板として使用する場合には、金属Ｃｒの電析に対しても悪影響を与える。従って、Ｓｉ含有量は少ないほど望ましく、上記悪影響を回避し得る０．１wt.%以下に限定する。
【００２９】
Ｍｎ：Ｍｎは、鋼中のＳをＭｎＳとして析出させることにより、スラブの熱間割れを防止すると共に、固溶強化元素として、Ｃによる強化を補う役割を果たす作用を有している。しかしながら、Ｍｎ含有量が０．１wt.%未満では、上記作用を発揮させることができず、一方、Ｍｎ含有量が１．０wt.%を超えると、素材の強度を高めることはできても、深絞り性、面内異方性の劣化を招く。従って、Ｍｎ含有量を０．１〜１．０wt.%の範囲内に限定する。
【００３０】
Ｐ：ＰもＭｎと同様に置換型固溶元素であり、Ｍｎ以上に大きな強化能を有し、鋼板の高強度化を図るために有効な元素であるが、同時にフェライト粒界に偏析して、粒界脆化を引き起こす。更に、Ｐが多量に含有されていると、粒界偏析による製缶時の破断等をもたらしまた耐食性の劣化を招く。従って、Ｐ含有量は少ないほど望ましく、上記悪影響を回避し得る０．０２wt.%以下に限定する。
【００３１】
Ｓ：Ｓは、スラブの熱間割れを防止する観点からその含有量は極力少ない方が望ましく、０．０２wt.%以下に限定する。
sol.Al：sol.Alは、鋼中のＮをＡｌＮとして析出させる作用を有している。しかしながら、sol.Alが０．０２wt.%未満では、上記作用を発揮させることができず、一方、sol.Al含有量が０．１５wt.%を超えると、 Al2O3系介在物が残留し、製缶時に介在物に起因する割れが発生しやすくなり、加工性の劣化を招く。従って、sol.Al含有量を、０．０２〜０．１５wt.%の範囲内に限定する。
【００３２】
Ｎ：Ｎ含有量は極力少ない方が望ましく、０．０１wt.%を超えると、固溶Ｎ量が増大して、深絞り性が劣化する。従って、Ｎ含有量を０．０１wt.%以下に限定する。
【００３３】
Ｂ：Ｂは、鋼中のＮと結合してＢＮを形成し、固溶Ｎ量を低減させ、深絞り性を向上させる作用を有している。また、鋼中のＮをＡｌＮとなる前にＢＮとして析出させることにより、巻取り後の熱延鋼板の幅方向、長手方向の組織の均一性を高める作用を有している。従って、必要に応じて、Ｂを含有させる。
【００３４】
しかしながら、Ｂ含有量が０．０００３wt.%未満では上記作用を発揮させることができず、一方、Ｂ含有量が０．００３wt.%を超えると、上記作用が飽和するのみならず、逆に固溶Ｂが増加して深絞り性の劣化を招く。従って、Ｂ含有量を、０．０００３〜０．００３wt.%の範囲内に限定する。
【００３５】
次に、この発明における、鋼板の製造条件について以下に述べる。この発明においては、上述した成分組成の鋼を転炉において溶製し、溶製された鋼を連続鋳造する。得られた連続鋳造薄スラブまたは連続鋳造スラブを粗圧延した粗バーを、熱間仕上圧延機の入側に配置された誘導加熱装置によってその幅方向全体を加熱し、仕上圧延入側温度を調整した後、熱間圧延する。
【００３６】
誘導加熱装置によって幅方向全体の加熱を行う素材としては、連続鋳造ままの薄スラブ、連続鋳造スラブを再加熱することなしに粗圧延した粗バー、または、連続鋳造スラブをいったん冷却し、加熱炉において再加熱した後、粗圧延した粗バーの何れであってもよい。上記薄スラブまたは粗バーの加熱装置としては、制御応答性が良好で、非接触で短時間に急速加熱を行うことが可能な誘導加熱方式の加熱装置を使用する。
【００３７】
図１および図２に示したように、エッジヒーターによるエッジ部近傍のみの加熱では、本発明の目的とする極薄の缶用鋼板の母材となる、板厚２．３mm以下特に１．８mm以下の薄手熱延鋼板の場合に、先端部の仕上圧延出側温度（ＦＴ）をＡｒ3 変態点以上とすることが困難であるため、幅方向全体を加熱することが必要である。このように幅方向全体を加熱し、仕上圧延出側温度（ＦＴ）を全長、全幅にわたりＡｒ3 〜Ａｒ3 ＋４０℃の範囲内に制御することによって、缶用鋼板の面内異方性の均一性を良好に保つことが可能になる。
【００３８】
仕上圧延出側温度（ＦＴ）がＡｒ3 変態点未満では、熱延鋼板に集合組織が形成されると共に、巻取り温度に応じて表層の結晶粒が粗大化したり、加工組織が残存するようになり、冷間圧延し焼鈍した鋼板の面内異方性が劣化し、コイル全体の面内異方性の均一性が低下する。
【００３９】
一方、仕上圧延出側温度（ＦＴ）がＡｒ3 ＋４０℃を超える高温になると、熱延鋼板の組織が過度に粗粒化して、前記ＦＴがＡｒ3 ＋４０℃以下の他の部位との面内異方性の差が顕著になり、面内異方性の均一性が低下する。更に、冷間圧延し焼鈍した後の鋼板の結晶粒も大きくなるために、製缶時に肌荒れが発生しやすくなり、また、仕上圧延中に生ずる二次スケールによる表面性状の低下が顕著になる。従って、仕上圧延出側温度（ＦＴ）は、Ａｒ3 変態点以上、Ａｒ3 ＋４０℃以下とすることが必要である。
【００４０】
更に、熱延鋼帯の先端部と後端部との仕上圧延出側温度（ＦＴ）の差が、２０℃以下となるように制御することが好ましい。このように熱延鋼帯の先端部と後端部とのＦＴの差が２０℃以下となるように制御するためには、薄スラブまたは粗バーの少なくとも長手方向先端部の幅方向全体を加熱し、先端部の表面温度を４５℃以上昇温させることが有効である。
【００４１】
また、鋼帯幅方向における仕上圧延出側温度（ＦＴ）の均一性を一段と高めて、面内異方性の幅方向均一性を更に向上させるために、粗圧延機と誘導加熱装置との間、または、誘導加熱装置と仕上圧延機との間にエッジヒータを配置し、このエッジヒータによって鋼帯エッジ部のみを加熱する工程を付加することが望ましい。
【００４２】
熱間仕上圧延された熱延鋼帯の巻取り温度は、５４０〜７００℃の範囲内とすることが好ましい。鋼帯巻取り温度が５４０℃未満では、熱延鋼板の組織に加工組織が残り面内異方性が劣化しやすくなる。一方、巻取り温度が７００℃を超えると、熱延鋼板の組織の一部が過度に粒成長し、粗大粒が発生して混粒になりやすくなり、面内異方性および面内異方性の均一性の劣化を引き起こす。また、酸洗性が低下して、表面性状が劣化すると共に、製缶時に肌荒れが発生するおそれも生ずる。熱延鋼帯のより好ましい巻取り温度は６００〜６８０℃である。
【００４３】
上述した条件で熱間仕上圧延が行われコイルに巻き取られた熱延鋼帯は、酸洗した後、冷間圧延される。熱延鋼帯の冷間圧延時における圧下率は、８０〜９５％とすることが好ましい。圧下率が８０％未満では、０度、９０度方向の耳が大きくなりやすくなり、一方、圧下率が９５％を超えると、４５度方向の耳が大きくなりやすくなる。これらの耳発生を抑制し、安定して面内異方性を小さくするために、上述した範囲の圧下率とすることが必要である。
【００４４】
上述した圧下率で冷間圧延された冷延鋼帯は、次いで焼鈍される。焼鈍は、バッチ焼鈍でも連続焼鈍でもよいが、生産性の観点からは連続焼鈍の方が好ましい。焼鈍温度は、再結晶温度〜７５０℃の範囲内とすることが好ましい。焼鈍温度が再結晶温度未満では面内異方性が劣化し、一方、焼鈍温度が７５０℃を超えると、本発明のように、最終製品板厚が０．２５mm以下の極薄鋼板の場合には、連続焼鈍炉の通板性が著しく劣化し、板破断、形状不良等のトラブルが発生しやすくなり、生産性が低下する。また、結晶粒が粗粒化し製缶時に肌荒れが発生するおそれが生じる。
【００４５】
連続焼鈍の場合の過時効処理は、これを行ってもまた行わなくても本発明の効果に変わりはない。過時効処理を行う場合には、連続焼鈍炉内のインライン過時効処理、連続焼鈍後の箱焼鈍によるバッチ過時効処理の何れの方法を実施してもよい。
【００４６】
上述のようにして焼鈍された鋼帯に対し、調質圧延または二次圧延を施して、板厚０．２５mm以下の鋼帯に仕上げる。本発明においては、近年のゲージダウンニーズに合致した極薄の２ピース缶用鋼板を対象としているので、最終製品板厚を０．２５mm以下に限定する。調質圧延の際の伸長率は、０．５％以上とすることが望ましい。伸長率が０．５％未満であると、形状制御が困難になる。また、二次圧延の際の圧下率は、３５％以下とすることが望ましい。圧下率が３５％を超えると、過度の硬質化および深絞り性の劣化を招き、製缶時に破断等のトラブルが誘発されるおそれが生ずる。
【００４７】
調質圧延または二次圧延された鋼帯に対し、錫めっき、極薄錫めっき、錫−ニッケルめっき、ニッケルめっき、クロムめっき等の各種の表面処理が施される。特に、ＤＩ缶用鋼板の場合には、ノーリフローの錫めっき鋼板が望ましく、ＤＴＲ缶用のフィルムラミネート鋼板、プレコート鋼板の下地鋼板として使用する場合には、加工密着性の観点から、ティンフリースチール（ＴＦＳ）が最も望ましい。これらの表面処理鋼板は、鋼板単独のまま、または、ポリエステル等の樹脂フィルムをラミネートしたフィルムラミネート鋼板、エポキシ等の塗料をコーティングしたプレコート鋼板としても使用することができる。
【００４８】
【実施例】
次に、この発明を実施例により比較例と対比しながら説明する。
表１に示す、本発明の範囲内の化学成分組成を有する鋼を転炉にて溶製し、次いで、連続鋳造することによってスラブを調製した。このスラブを、粗圧延後、表２に示す条件で圧延し焼鈍した。熱延鋼帯の巻取り温度は６２０℃とし、焼鈍は、均熱温度６５０℃の連続焼鈍とした。次いで、調質圧延または二次圧延によって所定の板厚に仕上げた後、電解クロム酸処理を施して表２に示す２ピース缶用電解クロム酸処理鋼板（ＴＦＳ）の供試体No. １〜２８を調製した。
【００４９】
【表１】
【表２】
表２において、No. １、２、６、７、１１、１２、１６、１７、２３、２６は、熱間圧延前に粗バーに対する幅方向全体の加熱を行わなかった比較例であり、その他は本発明例である。このような、本発明例および比較例の供試体に対し、コイル長手方向中央部の幅中央部とコイル長手方向先端部の幅中央部およびエッジ部のイヤリング率を測定し、その測定結果を表２に併せて示した。なお、イヤリング率は、絞り比１．８で深絞り成形後に耳高さを測定し、耳の最大値と最小値との差を耳全周の平均値で割った百分率で表し、これによって面内異方性を評価した。
【００５２】
表２から明らかなように、本発明例の場合には比較例に比べてコイル長手方向中央部のみならず、コイル先端部の幅中央部およびエッジ部のイヤリング率も小さく、面内異方性が良好であり、且つ、コイル内均一性にも優れていた。
【００５３】
【発明の効果】
以上述べたように、この発明によれば、コイルの全長、全幅の全域において、面内異方性が小さく、且つ、面内異方性のコイル内均一性に優れた２ピース缶用極薄鋼板を製造することができ、ＤＲＤ缶、ＤＩ缶、ＤＴＲ缶のような２ピース缶を製造する際の耳発生による歩留り低下が小さくなり、その製造コストを低減することができる等、工業上有用な効果がもたらされる。
【図面の簡単な説明】
【図１】熱延鋼帯の長手方向、幅方向の仕上出側温度（ＦＴ）の変動に対する粗バー全体の加熱効果を示す図である。
【図２】イヤリング率のコイル内均一性に対する粗バー全体の加熱効果を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a steel plate for a two-piece can that is excellent in in-plane anisotropic uniformity in a coil.
[0002]
[Prior art]
Steel plates for cans, such as tin-plated steel plates with tin plating on the surface of steel plates or tin-free steel (TFS) with electrolytic chromic acid treatment on the surfaces of steel plates, are often used as steel plates for food cans and beverage cans Has been. These food cans and beverage cans are classified into three-piece cans and two-piece cans because of differences in the can-making methods, but in recent years, mainly for beverage cans, weight reduction of can bodies, omission of the can-making process, From the viewpoint of reducing raw materials and manufacturing costs, etc., the transition from a three-piece can to a two-piece can and further the thinning of the can body have been promoted.
[0003]
Two-piece cans for food and beverage cans include DRD cans (Drawn and redrawn cans) manufactured by drawing and redrawing, and DTR cans manufactured by multi-stage drawing with thinning of the can body ( Drawn-thin-redrawn can) and DI can (Drawn and wall ironed can) that are subjected to ironing after drawing, but in any of these cases, the can is made by drawing from a disk-shaped blank plate The method includes forming a cup-shaped can body or forming a cup-shaped can body having a smaller diameter and a deeper depth by redrawing from the cup-shaped can body.
[0004]
Due to the in-plane anisotropy of the workability of the steel sheet, the height of the end of the can or the width of the flange is often along the circumferential direction during the drawing process in the case of such a two-piece can. And so-called ears are generated. This ear is trimmed and removed before necking the can end. However, if the ear is large, the trim margin becomes large and the material yield is lowered.
[0005]
Furthermore, the ears cause fluctuations in the thickness distribution along the circumferential direction, which not only causes neck wrinkles during necking processing in the subsequent process, but also causes punch missing when the can body is removed from the punch during molding. It also causes the occurrence of defects, leading to a decrease in material yield and quality.
[0006]
For this reason, steel plates for two-piece cans are required to have low ear generation during can making, that is, low in-plane anisotropy, and particularly steel plates for DI cans and steel plates for DTR cans. In view of the reduction in weight of cans and the reduction of manufacturing costs, which are required in recent years, the in-plane anisotropy is much smaller and the in-plane anisotropy can be improved, and the material yield can be improved. There is a strong demand for a steel sheet in which anisotropy is uniform over the entire length and width of the coil.
[0007]
As a method for producing a steel plate for a two-piece can with small in-plane anisotropy, for example, in JP-A-9-241756, the crystal grain size before cold rolling is controlled to 30 μm or more to reduce earrings (hereinafter, And prior art 1).
[0008]
On the other hand, as a method for producing a steel plate for cans having a uniform material in the plate width direction, Japanese Patent Application Laid-Open No. 10-46243 discloses that the end temperature of rolling is increased by heating and heating both ends of a roughly rolled sheet bar. A method in which hot finish rolling is performed so as to be less than Ar 3 transformation point and (Ar 3 transformation point−100 ° C.) or more over the entire width of the steel strip, and then cold rolling, annealing and temper rolling (hereinafter, prior art) 2).
[0009]
[Problems to be solved by the invention]
However, the prior art 1 includes a technical idea of suppressing the non-uniformity in the longitudinal direction and the width direction of the coil, in other words, improving the uniformity in the longitudinal direction and the width direction of the coil as compared with the prior art. Absent. Accordingly, it is not possible to avoid a decrease in the earring property, that is, the in-plane anisotropy at the end portions in the longitudinal direction and the width direction of the coil, and the variation in the in-plane anisotropy due to the blanking position in the coil increases. The problem of yield loss has not been solved.
[0010]
Prior art 2 is a technique for setting the hot rolling finishing temperature below the Ar 3 transformation point, and is a technique that is essentially different from the technique intended by the present invention. Although the material uniformity in the direction is improved, it is difficult to say that the uniformity in the longitudinal direction of the steel sheet is sufficient.
[0011]
That is, in order to improve the uniformity in the longitudinal direction of the steel sheet, it is necessary to further wind the sheet bar before finish rolling, reverse the front end and the rear end, and join the preceding sheet bar. In addition, the hot rolling process needs to be remodeled and ancillary equipment must be installed, resulting in a significant increase in manufacturing costs. Furthermore, even if such a technique is used, it is difficult to sufficiently meet the current strict requirements for the steel plate for two-piece cans regarding the uniformity in the longitudinal direction of the steel plate, and further improvement is required. .
[0012]
Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for manufacturing a steel plate for a two-piece can that can sufficiently meet the current requirements and has excellent in-plane anisotropic coil uniformity. It is to provide.
[0013]
[Means for Solving the Problems]
The inventors of the present invention have made extensive studies to solve the above-described problems and to develop a method for producing a steel plate for a two-piece can that is excellent in in-plane anisotropic coil uniformity.
[0014]
As the gauge of steel plates for two-piece cans progresses, the finish thickness of hot-rolled steel sheets has also decreased, but the heat release during hot rolling has increased due to the thinning of hot-rolled steel sheets. The temperature drop of the part is large, and it is difficult to make the finish rolling outlet temperature (FT) equal to or higher than the Ar 3 transformation point. Therefore, even if good in-plane anisotropy can be maintained at the central portion in the longitudinal direction of the coil, there arises a problem that the in-plane anisotropy is greatly deteriorated at the front end of the steel plate.
[0015]
The inventors of the present invention have found that the deterioration of the in-plane anisotropy of the ultrathin two-piece can steel sheet, particularly the deterioration of the in-plane anisotropy at the front end of the steel strip in the longitudinal direction during hot finish rolling. Based on the idea that this is because the finish rolling exit temperature (FT) of the steel sheet falls below the Ar 3 transformation point, a method for avoiding this was investigated. As a result, it has been found that it is most effective and economical to heat the entire width direction of the rough bar before finish rolling with an induction heating device and adjust the finish rolling entry temperature.
[0016]
FIG. 1 shows the ratio of the rough bar to the finish rolling exit temperature (FT) when a continuously cast slab having a chemical composition containing 0.04 wt.% C is used and the hot-rolled finish thickness is 1.6 mm. It is a figure which shows the result of having investigated the heating (coarse bar whole heating) effect by the induction heating apparatus apparatus of the whole width direction, and FIG. 2 is a figure which shows the coarse bar whole heating effect with respect to the uniformity in the coil of an earring rate.
[0017]
In-plane anisotropy was evaluated by measuring the earring rate of a steel sheet finished to a thickness of 0.17 mm by performing pickling, cold rolling, annealing, and temper rolling after hot rolling. The earring rate was expressed as a percentage obtained by measuring the ear height when deep drawing was performed at a drawing ratio of 1.8, and dividing the difference between the maximum value and the minimum value of the ear by the average value of the entire circumference of the ear.
[0018]
As is clear from FIGS. 1 and 2, when the coarse bar heating is not performed, the reduction in finish rolling temperature (FT) at the tip portion (T portion in the figure) of the hot-rolled steel strip is large, and the Ar 3 transformation The earring rate is deteriorated, and the uniformity of the earring rate in the steel plate width direction and the longitudinal direction is very poor. When only the vicinity of the edge portion of the coarse bar is heated by the edge heater, the decrease in FT at the edge portion is suppressed and the earring rate at the edge portion is slightly improved. The FT is less than the Ar 3 transformation point in both the part and the edge part, and deterioration of the earring rate cannot be avoided.
[0019]
On the other hand, when the entire coarse bar is heated, the finish rolling outlet temperature (FT) is equal to or higher than the Ar 3 transformation point and is uniform over the entire length and the entire width including the edge at the front end in the longitudinal direction. Temperature can be set, deterioration of the earring rate at the tip portion or the edge portion is not recognized, and the in-coil uniformity of the in-plane anisotropy becomes very good.
[0020]
Thus, in order to produce a steel plate for a two-piece can that is excellent in in-plane anisotropic coil uniformity, it is possible to control the finish rolling exit temperature (FT) in the hot rolling process within the optimum range. It was important, and for that purpose, it was found that it was effective to heat the entire width direction of the coarse bar and adjust the finish rolling entry temperature.
[0021]
This invention has been made on the basis of the above-mentioned findings. The invention according to claim 1 of the present application includes C: 0.01 to 0.10 wt.% , Si: 0.1 wt.% Or less, Mn : 0.1-1.0 wt.% , P: 0.02 wt.% Or less, S: 0.02 wt.% Or less, sol. Al:. 0.02~0.15 wt%, N :. 0.01 wt% or less, coarse bar was rough rolling continuous casting thin slab or a continuous cast slab having a chemical composition the balance being Fe and unavoidable impurities In the hot finish rolling on the steel strip, the entire width direction of the thin slab or the coarse bar is heated by an induction heating device arranged on the entry side of the hot finish rolling mill, and the finish rolling entry side The temperature is adjusted, and the finish rolling exit temperature is not less than Ar 3 transformation point and not more than Ar 3 + 40 ° C. over the entire length from the leading end to the trailing end of the steel strip, and the finishing plate thickness is 2.3 mm. The thin slab or the rough bar is hot-finished to prepare a hot-rolled steel strip, and the resulting hot-rolled steel strip is wound on a coil and pickled, and then cold-rolled, The obtained cold-rolled steel strip is annealed and then subjected to temper rolling or secondary pressure Subjected to plate thickness 0.25mm or less of the strip and without, then it has the characteristics to be subjected to a surface treatment to the steel strip.
[0022]
Invention of Claim 2 is C: 0.01-0.10 wt.%, Si: 0.1 wt.% Or less, Mn: 0.1-1.0 wt.%, P: 0.02 wt.% Or less , S: 0.02 wt.% Or less, sol. Al:. 0.02~0.15wt%, N: . 0.01wt% or less, the continuously cast thin slab or coarse bar continuous casting slabs were rough rolling having a chemical composition the balance being Fe and unavoidable impurities, When hot finishing rolling on a steel strip, the entire width direction of the thin slab or coarse bar is heated by an induction heating device arranged on the entry side of the hot finish rolling mill to adjust the finish rolling entry temperature. The finish rolling exit temperature is not less than Ar 3 transformation point and not more than Ar 3 + 40 ° C. over the entire length from the front end to the rear end of the steel strip, and the finished plate thickness is 2.3 mm or less. The thin slab or the rough bar is hot finish-rolled to prepare a hot-rolled steel strip, and the obtained hot-rolled steel strip is wound on a coil at a temperature of 540 to 700 ° C. and pickled, Cold-rolled steel strip obtained by cold rolling at a reduction rate of ~ 95% Annealed then temper rolling or subjected to secondary rolling, thickness 0.25mm below the steel strip and without, then it has the characteristics to be subjected to a surface treatment to the steel strip.
[0023]
The invention described in claim 3 is characterized in that the continuously cast thin slab or the coarse bar further contains 0.0003 to 0.003 wt.
The invention according to claim 4 is characterized in that, in the hot-rolled steel strip, the difference between the finish rolling exit temperature at the leading end and the finish rolling exit temperature at the trailing end is 20 ° C. or less. .
[0024]
The invention according to claim 5 is characterized in that at least the longitudinal direction tip portion of the continuous cast thin slab or the rough bar is heated over the entire width direction, and the surface temperature of the tip portion is raised by 45 ° C. or more. It is what has.
[0025]
In the invention according to claim 6, an edge heater is arranged between the rough rolling mill and the induction heating apparatus or between the induction heating apparatus and the finishing rolling mill, and the edge of the coarse bar is arranged by the arranged edge heater. It is characterized by heating only the part.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The reason why the chemical composition of steel is limited as described above in the method of the present invention will be described below.
[0027]
C: When the C content is less than 0.01 wt.%, The hot-rolled sheet structure is likely to be coarsened and mixed, and the uniformity of the structure at the hot-rolling stage is lowered and the grain after annealing is reduced. The diameter tends to be large and rough skin is likely to occur during canning. On the other hand, if the C content exceeds 0.10 wt.%, The amount of solid solution C in the ferrite grains, the amount of C segregated at the grain boundaries, and the amount of carbides increase, so that deep drawability deteriorates and in-plane Anisotropy also deteriorates. Therefore, in the present invention, it is fundamental to limit the C content within the range of 0.01 to 0.10 wt.%. A more preferable C content is in the range of 0.015 to 0.06 wt.%.
[0028]
Si: Si is an element that remains in the steel as an impurity component even when this is not intentionally added, embrittles the steel sheet and degrades the corrosion resistance. Moreover, when it uses as a base steel plate of TFS, it has a bad influence also on the electrodeposition of metal Cr. Therefore, the smaller the Si content, the better, and the content is limited to 0.1 wt.
[0029]
Mn: Mn precipitates S in steel as MnS, thereby preventing hot cracking of the slab and has an effect of supplementing strengthening by C as a solid solution strengthening element. However, if the Mn content is less than 0.1 wt.%, The above-described effect cannot be exhibited. On the other hand, if the Mn content exceeds 1.0 wt.%, The strength of the material can be increased. Degradation of deep drawability and in-plane anisotropy is caused. Therefore, the Mn content is limited to a range of 0.1 to 1.0 wt.
[0030]
P: P is a substitutional solid solution element similar to Mn. It has a greater strengthening ability than Mn and is an effective element for increasing the strength of steel sheets. Cause grain boundary embrittlement. Further, when P is contained in a large amount, it causes breakage at the time of can making due to grain boundary segregation and also causes deterioration of corrosion resistance. Therefore, the P content is preferably as small as possible, and is limited to 0.02 wt.
[0031]
S: The content of S is preferably as small as possible from the viewpoint of preventing hot cracking of the slab, and is limited to 0.02 wt.% Or less.
sol.Al: sol.Al has a function of precipitating N in steel as AlN. However, if the sol.Al content is less than 0.02 wt.%, The above-mentioned effect cannot be exhibited. On the other hand, if the sol.Al content exceeds 0.15 wt.%, Al 2 O 3 inclusions remain. However, cracks due to inclusions are likely to occur during can making, resulting in deterioration of workability. Therefore, the sol.Al content is limited to the range of 0.02 to 0.15 wt.%.
[0032]
N: N content is preferably as low as possible. If it exceeds 0.01 wt.%, The amount of dissolved N increases and deep drawability deteriorates. Therefore, the N content is limited to 0.01 wt.% Or less.
[0033]
B: B combines with N in steel to form BN, and has the effect of reducing the amount of solute N and improving deep drawability. Moreover, it has the effect | action which improves the uniformity of the structure | tissue of the width direction of a hot-rolled steel plate after winding, and a longitudinal direction by precipitating N in steel as BN before becoming AlN. Therefore, B is contained as necessary.
[0034]
However, when the B content is less than 0.0003 wt.%, The above-described effect cannot be exhibited. On the other hand, when the B content exceeds 0.003 wt. Molten B increases and deep drawability deteriorates. Therefore, the B content is limited to a range of 0.0003 to 0.003 wt.%.
[0035]
Next, the manufacturing conditions of the steel sheet in this invention will be described below. In this invention, the steel of the component composition mentioned above is melted in a converter, and the melted steel is continuously cast. The resulting continuous cast thin slab or the rough bar obtained by roughly rolling the continuous cast slab is heated in the entire width direction by an induction heating device placed on the entry side of the hot finish rolling mill to adjust the finish rolling entry temperature. And then hot rolling.
[0036]
The raw material to be heated in the width direction by the induction heating device is a thin slab that is continuously cast, a rough bar that is roughly rolled without reheating the continuous cast slab, or a continuous cast slab that is once cooled and heated. Any of the rough bars that have been rough-rolled after being reheated in FIG. As the heating device for the thin slab or the coarse bar, an induction heating type heating device that has good control response and can perform rapid heating in a short time without contact is used.
[0037]
As shown in FIGS. 1 and 2, heating only in the vicinity of the edge portion with an edge heater serves as a base material for an ultrathin steel plate for cans, which is the object of the present invention. In the case of the following thin hot-rolled steel sheets, it is difficult to set the finish rolling exit temperature (FT) at the tip portion to the Ar 3 transformation point or higher, so it is necessary to heat the entire width direction. By heating the entire width direction in this way and controlling the finish rolling exit temperature (FT) within the range of Ar 3 to Ar 3 + 40 ° C. over the entire length and width, uniform in-plane anisotropy of the steel plate for cans It becomes possible to keep the property good.
[0038]
When the finish rolling exit temperature (FT) is less than the Ar 3 transformation point, a texture is formed on the hot-rolled steel sheet, and the crystal grains of the surface layer become coarse or the processed structure remains depending on the winding temperature. As a result, the in-plane anisotropy of the cold-rolled and annealed steel sheet deteriorates, and the uniformity of the in-plane anisotropy of the entire coil decreases.
[0039]
On the other hand, when the finish rolling exit temperature (FT) reaches a high temperature exceeding Ar 3 + 40 ° C., the structure of the hot-rolled steel sheet is excessively coarsened, and the FT is in-plane with other parts below Ar 3 + 40 ° C. The difference in anisotropy becomes noticeable, and the uniformity of in-plane anisotropy decreases. Further, since the crystal grains of the steel sheet after cold rolling and annealing become large, rough skin is liable to occur during can making, and the surface property is significantly reduced due to the secondary scale that occurs during finish rolling. Accordingly, the finish rolling delivery temperature (FT) is, Ar 3 transformation point or higher, it is necessary to Ar 3 + 40 ° C. or less.
[0040]
Furthermore, it is preferable to control so that the difference of finish rolling exit side temperature (FT) of the front-end | tip part and rear-end part of a hot-rolled steel strip may be 20 degrees C or less. In this way, in order to control the difference in FT between the front end and the rear end of the hot-rolled steel strip to be 20 ° C. or less, at least the entire width direction of the front end of the thin slab or the coarse bar is heated. It is effective to raise the surface temperature of the tip portion by 45 ° C. or more.
[0041]
In order to further improve the uniformity of the finish rolling exit temperature (FT) in the steel strip width direction and further improve the in-plane anisotropy width direction uniformity, Alternatively, it is desirable to add a step of arranging an edge heater between the induction heating device and the finishing mill and heating only the edge portion of the steel strip by the edge heater.
[0042]
The coiling temperature of the hot rolled steel strip that has been hot-finished and rolled is preferably in the range of 540 to 700 ° C. When the steel strip winding temperature is less than 540 ° C., the processed structure remains in the structure of the hot-rolled steel sheet, and the in-plane anisotropy tends to deteriorate. On the other hand, when the coiling temperature exceeds 700 ° C., a part of the structure of the hot-rolled steel sheet grows excessively, and coarse grains are easily generated and become mixed grains. In-plane anisotropy and in-plane anisotropy Cause deterioration of uniformity of sex. In addition, the pickling property is lowered, the surface properties are deteriorated, and the skin may be roughened during the can making. A more preferable winding temperature of the hot-rolled steel strip is 600 to 680 ° C.
[0043]
The hot-rolled steel strip that has been hot-finished and rolled on the coil under the conditions described above is pickled and then cold-rolled. The rolling reduction during cold rolling of the hot-rolled steel strip is preferably 80 to 95%. When the rolling reduction is less than 80%, the ears in the directions of 0 ° and 90 ° tend to be large. On the other hand, when the rolling reduction exceeds 95%, the ears in the 45 ° direction are likely to become large. In order to suppress the generation of these ears and stably reduce the in-plane anisotropy, it is necessary to set the rolling reduction in the above-described range.
[0044]
The cold-rolled steel strip that has been cold-rolled at the rolling reduction described above is then annealed. The annealing may be batch annealing or continuous annealing, but continuous annealing is preferable from the viewpoint of productivity. The annealing temperature is preferably within the range of the recrystallization temperature to 750 ° C. When the annealing temperature is lower than the recrystallization temperature, the in-plane anisotropy deteriorates. On the other hand, when the annealing temperature exceeds 750 ° C., as in the present invention, in the case of an ultrathin steel sheet having a final product thickness of 0.25 mm or less. However, the plate-passability of the continuous annealing furnace is remarkably deteriorated, and troubles such as plate breakage and shape defects are likely to occur, resulting in a decrease in productivity. In addition, the crystal grains may become coarse and rough skin may occur during can making.
[0045]
The effect of the present invention is not changed whether or not the overaging treatment in the case of continuous annealing is performed. When performing an overaging treatment, any of an inline overaging treatment in a continuous annealing furnace and a batch overaging treatment by box annealing after the continuous annealing may be performed.
[0046]
The steel strip annealed as described above is subjected to temper rolling or secondary rolling to finish a steel strip having a thickness of 0.25 mm or less. In the present invention, an extremely thin two-piece can steel plate that meets the recent gauge down needs is targeted, so the final product plate thickness is limited to 0.25 mm or less. The elongation ratio during temper rolling is preferably 0.5% or more. If the elongation rate is less than 0.5%, shape control becomes difficult. Moreover, it is desirable that the rolling reduction during secondary rolling be 35% or less. When the rolling reduction exceeds 35%, excessive hardening and deep drawability deteriorate, and troubles such as breakage may be induced during can making.
[0047]
Various surface treatments such as tin plating, ultra-thin tin plating, tin-nickel plating, nickel plating, and chromium plating are performed on the temper rolled or secondary rolled steel strip. In particular, in the case of steel plates for DI cans, a no-reflow tinned steel plate is desirable. (TFS) is most desirable. These surface-treated steel sheets can be used as a steel sheet alone, as a film-laminated steel sheet laminated with a resin film such as polyester, or as a pre-coated steel sheet coated with a paint such as epoxy.
[0048]
【Example】
Next, the present invention will be described by way of comparison with comparative examples.
Slabs were prepared by melting steel having a chemical composition within the scope of the present invention shown in Table 1 in a converter and then continuously casting it. After rough rolling, this slab was rolled and annealed under the conditions shown in Table 2. The coiling temperature of the hot-rolled steel strip was 620 ° C., and the annealing was continuous annealing at a soaking temperature of 650 ° C. Next, after finishing to a predetermined thickness by temper rolling or secondary rolling, electrolytic chromic acid treatment was performed, and specimens No. 1-28 of electrolytic chromic acid treated steel plates (TFS) for 2-piece cans shown in Table 2 were used. Was prepared.
[0049]
[Table 1]
[Table 2]
In Table 2, Nos. 1, 2, 6, 7, 11, 12, 16, 17, 23, and 26 are comparative examples in which the entire width direction of the rough bar was not heated before hot rolling. These are examples of the present invention. For the specimens of the present invention example and the comparative example, the earring rate of the width center part of the coil longitudinal direction center part and the width center part and edge part of the coil longitudinal direction tip part is measured, and the measurement result is represented. It was shown together with 2. The earring rate is expressed as a percentage obtained by measuring the ear height after deep drawing at a drawing ratio of 1.8, and dividing the difference between the maximum and minimum values of the ear by the average value of the entire circumference of the ear. The internal anisotropy was evaluated.
[0052]
As can be seen from Table 2, in the case of the present invention example, not only the coil longitudinal direction center part but also the earring rate of the width center part and the edge part of the coil tip part is small and in-plane anisotropy as compared with the comparative example. And the uniformity within the coil was also excellent.
[0053]
【The invention's effect】
As described above, according to the present invention, the in-plane anisotropy is small throughout the entire length and width of the coil, and the two-piece can is extremely thin with excellent in-plane anisotropy uniformity in the coil. Steel plate can be manufactured, and industrially useful, such as reduction in yield due to generation of ears when manufacturing two-piece cans such as DRD cans, DI cans, and DTR cans, and the manufacturing cost can be reduced. Effect.
[Brief description of the drawings]
FIG. 1 is a diagram showing the heating effect of the entire coarse bar on the variation in the finish side temperature (FT) in the longitudinal direction and width direction of a hot-rolled steel strip.
FIG. 2 is a diagram showing the heating effect of the entire coarse bar on the uniformity of the earring rate in the coil.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25843498A JP3682683B2 (en) | 1998-09-11 | 1998-09-11 | Method for producing steel plate for two-piece can with excellent in-plane anisotropic uniformity in coil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25843498A JP3682683B2 (en) | 1998-09-11 | 1998-09-11 | Method for producing steel plate for two-piece can with excellent in-plane anisotropic uniformity in coil |
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| Publication Number | Publication Date |
|---|---|
| JP2000087145A JP2000087145A (en) | 2000-03-28 |
| JP3682683B2 true JP3682683B2 (en) | 2005-08-10 |
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| CN102965487B (en) * | 2012-12-03 | 2014-01-15 | 安徽工业大学 | Preparation method of cold-rolled deep punching plate |
| KR101989712B1 (en) * | 2014-10-28 | 2019-06-14 | 제이에프이 스틸 가부시키가이샤 | Steel sheet for two-piece can and manufacturing method therefor |
| WO2018180404A1 (en) * | 2017-03-27 | 2018-10-04 | Ｊｆｅスチール株式会社 | Steel sheet for two-piece can and production method therefor |
| CN110494581B (en) | 2017-03-27 | 2021-07-09 | 杰富意钢铁株式会社 | Two-piece steel sheet for can and method for producing same |
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