JP4148551B2 - Manufacturing method of cold-rolled steel strip with less variation in material property values - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、製鋼、熱延、冷間工程（めっき工程を含む）における製造条件が変動しても、下工程の製造条件を変更することにより、材質特性値のばらつきを低減できる冷延鋼帯（溶融鍍金鋼板、電気鍍金鋼板、塗装鋼板、ブリキ用鋼板、電磁鋼板等を含む）の製造方法に関するものである。
【０００２】
【従来の技術】
鉄鋼生産において、製鋼、熱延、冷間工程を経て、所定の材質の冷延鋼帯を生産する場合、まず、顧客からの製品仕様を満足するように、製造を開始する前に、受注オーダー毎に、鋼種、鋼成分、スラブ加熱温度、熱間圧延温度、巻取り温度、冷間圧延率、焼鈍温度、スキンパスミル伸長率などの各工程の製造仕様を設定（以下、オーダー標準という）する。次に、当該材料が各々の工程に装入される前に、前記製造仕様を、当該工程を統括する計算機に伝送しあるいは運転員に指示して製造を行っている。
【０００３】
図４は、従来技術の処理フローの一例を示すフローチャートで、連続焼鈍工程を経由して冷延鋼板を製造する場合である。客先の要求する製品をつくるために、オーダー情報を基にして鋼種、鋼成分や製造条件などのオーダー標準を設定し、オーダー標準を計画情報のデータベース（計画ＤＢ）に保管している。実際に使用した鋼種や実際の操業条件に関する情報（現品情報）は、現品情報のデータベース（現品ＤＢ）に保有している。
【０００４】
通常、実績鋼成分とオーダー標準の製造仕様の鋼成分には幾分差がある。この差は、後工程の作業指示には反映されない。また、製鋼、熱延工程における実績製造条件にも、オーダー標準の製造仕様からのずれがある。これらのオーダー標準の製造仕様との差やずれによって、材質特性値のずれが大きくなり、所望の材質特性値の最終製品が得られないという問題がある。
【０００５】
前記の問題点を改善する方法が、特開平５−２７３１９９号公報に提案されている。前記提案では、図５に示すように、出鋼成分値Ｓ２０１、製鋼実績Ｓ２０８および材質判定ＦＦ処理（Ｓ１００）の結果から、熱延作業指示Ｓ２０９を行う。
【０００６】
材質判定ＦＦ処理の内容は、図６に示される。図６において、材質判定ＦＦテーブルＳ２０５には、熱延工程〜冷間工程までの後工程条件を５水準設定してある。判定式係数基準値テーブルＳ２０７には、各鋼成分および製鋼の後工程の各作業条件毎の材質判定係数が設定してある。
【０００７】
出鋼成分情報と製鋼実績に基いて、材質判定ＦＦテーブルＳ２０５および判定式係数基準値テーブルＳ２０７を用いて、材質判定ＦＦテーブルを作成し（Ｓ１０３）、材質判定基準値テーブルＳ２０６等から材質判定基準値を設定し（Ｓ１０６）、前記後工程条件の各水準に対応する推定試験値を算出する（Ｓ１０８）。次いで、全材質試験項目の各々について、前記５水準の後工程条件に対応する推定試験値と材質判定基準値の目標値との差を、優先順位とともに材質判定結果として求める（Ｓ１１０）。前記材質判定結果で最も優先順位の高い水準の後工程条件を、後工程条件として採用し（Ｓ１１１）、図５に示すように、熱延作業指示をする（Ｓ２０９）。
【０００８】
また、冷間工程を通過するものは、図５に示すように、前記手順において、出鋼成分情報Ｓ２０１の代りに、熱延実績を保存するコイル管理ＤＢ（Ｓ２１２）を用いて、材質判定ＦＦ処理し（Ｓ２１１）、冷間作業指示を行う（Ｓ２１３）。
【０００９】
前記のようにして、後工程条件として、優先順位の最も高い水準の条件が採用され、後工程では、この条件で製造されるので、材質が均一で、希望通りの製品が製造できるとされている。
【００１０】
【発明が解決しようとする課題】
前記提案が、所望の効果をあげるには、推定試験値を算出するために設定する５水準の後工程条件の少なくとも１つが、所望の材質を得る上で最適の条件に設定されていることが不可欠である。しかし、前記公報には、５水準の条件をいかなる条件で設定するかについて、全く記載されておらず、設定された５水準の条件が、所望の材質を得る上で最適な条件が選ばれているという保証がない。
【００１１】
したがって、前記提案では、ある程度材質を均一にできるという効果があるにしても、いつも所望の材質の製品が得られるということが保証されていないという問題がある。
【００１２】
また、出鋼後、連続鋳造の際の鋼中［Ｃ］や［Ｎ］のピックアップ等、スラブの鋼成分が出鋼成分と異なるようになる場合もある。極低炭素鋼のように、鋼中［Ｃ］量や［Ｎ］量が材質に大きく影響する鋼種では、出鋼成分に基いて推定試験値を算出しても、算出した試験値の精度が著しく劣る。したがって、出鋼成分情報に基づいて推定試験値を算出する前記提案では、極低炭素鋼のように、鋼中［Ｃ］や［Ｎ］のピックアップが問題になる鋼種については、材質の均一化や所望の材質にするという効果を期待できない。
【００１３】
本発明は、前記問題点を考慮したものであり、材質特性値のばらつきが少なく、あるいは所望の材質特性値の冷延鋼板または溶融亜鉛鍍金鋼板を製造できるようにすることにある。
【００１４】
【課題を解決するための手段】
前記課題を解決するための本発明の手段は、（１）製鋼、熱延、冷間工程（めっき工程を含む）の各製造工程を経て、所定の材質の冷延鋼帯を製造するに際して、材質特性値を目標値に近づけるように、実績鋼成分情報に基いて、予め設定した各製造工程の作業条件を、操業性と操業コストを考慮して定めた変更優先順位に従って、熱延工程は、巻取温度、仕上温度、スラブ加熱温度、熱延板板厚の順に、および／または、冷間工程は、スキンパスミル伸長率、焼鈍温度、ライン速度、焼き入れ開始温度、冷却速度の順に、操業性、製造コスト、材質以外の品質影響を考慮して定めた一定の操作範囲内で順次修正して再設定し、再設定した作業条件に基いて冷延鋼帯を製造することを特徴とする材質特性値のばらつきの少ない冷延鋼帯の製造方法であり、（２）製鋼、熱延、冷間工程（めっき工程を含む）の各製造工程を経て、所定の材質の冷延鋼帯を製造するに際して、材質特性値を目標値に近づけるように、実績鋼成分情報に基いて、予め設定した各製造工程の作業条件を、操業性と操業コストを考慮して定めた変更優先順位に従って、熱延工程は、巻取温度、仕上温度、スラブ加熱温度、熱延板板厚の順に、および／または、冷間工程は、スキンパスミル伸長率、焼鈍温度、ライン速度、焼き入れ開始温度、冷却速度の順に、操業性、製造コスト、材質以外の品質影響を考慮して定めた一定の操作範囲内で順次修正して再設定し、熱延工程は、再設定した作業条件で作業を行い、さらに前記製造工程の上工程の実績作業条件を反映して、予め設定した下工程の作業条件を、操業性と操業コストを考慮して定めた変更優先順位に従って、冷間工程は、スキンパスミル伸長率、焼鈍温度、ライン速度、焼き入れ開始温度、冷却速度の順に、操業性、製造コスト、材質以外の品質影響を考慮して定めた一定の操作範囲内で順次再度修正して再設定し、再度修正して再設定した作業条件に基いて冷延鋼帯を製造することを特徴とする材質特性値のばらつきの少ない冷延鋼帯の製造方法である。
【００１５】
（作用）
実績鋼成分に基いて、オーダー標準の標準仕様の鋼成分との成分のずれを把握し、このずれに基く材質特性値の目標値からのずれを少なくするように、製造工程の作業条件を修正して再設定し、あるいはまた製造工程の上工程における実績作業条件のオーダー標準の製造仕様からのずれを下工程の作業条件に反映して、前記材質特性値の目標値からのずれを少なくするように修正するので、修正した作業条件で製造される冷延鋼帯の材質特性値のばらつきを少なく、あるいは所望の材質特性値にできる。
【００１６】
また、各製造工程の作業条件の修正は、操業性と製造コストを考慮して定めた操作順位に従い、また操業性、製造コストと材質以外の品質影響を考慮して定めた一定の操作範囲内で行うので、作業条件の修正によって、操業に支障がでたり、製造コストが上昇したり、品質上の弊害が発生したりすることが少ない。
【００１７】
【発明の実施の形態】
以下、本発明について、具体的に説明する。
図１は、連続焼鈍工程を経由して冷延鋼板を製造する場合における本発明の主要な処理部分を示すフローチャートである。客先の要求する製品をつくるために、製造条件設定ブロックで、予め設定された製造条件設定プログラムに従って、受注オーダー毎に、オーダー情報を基にして、鋼種（鋼成分）、スラブ加熱温度、熱間圧延温度、巻取り温度、圧延率、焼鈍温度、スキンパスミル伸長率などの製造仕様が、オーダー標準として設定される。
【００１８】
また、オーダー標準には、受注規格に対応して、材質判定項目とその基準値、また必要に応じてその許容範囲、材質判定の優先順位などが設定される。オーダー標準は、計画情報のデータベース（計画ＤＢ）に保管されている。
【００１９】
表１は、オーダー標準の一例であり、鋼成分の基準値、各製造工程の基準作業条件が記載されている。
【００２０】
【表１】
オーダー標準に基く鋼成分や作業条件を各製造工程に指示して、所要の鋼板を製造する。実際に使用した鋼種や実際の操業条件に関する情報（現品情報）は、現品情報のデータベース（現品ＤＢ）に保有されている。
【００２２】
オーダー標準どおりの鋼成分、作業条件で製造できれば所望の材質が得られる。しかし、実操業においては、このオーダー標準から外れるケースが少なくない。本発明では、材質特性値のばらつきを少なくするため、鋼成分のオーダー標準からのずれを考慮して、製造工程の作業条件を修正し、また上工程における実績作業条件のオーダー標準からのずれを下工程の作業条件に反映して修正して、再設定する。以下、この点について、具体的に説明する。
【００２３】
なお、図１において、計画熱延条件、計画焼鈍条件等は、オーダー標準に設定された条件であり、修正熱延条件、修正焼鈍条件等は、実績鋼成分、実績作業条件等に基き、再設定された製造条件を表している。
【００２４】
先ず、設定されたオーダー標準にしたがって、製鋼工程の作業指示が行われる。製鋼工程では、この指示に従って、所定の成分組成の鋼を出鋼し、スラブにする。極低炭素鋼のように鋳造の際の鋼中［Ｃ］や［Ｎ］のピックアップが問題になる鋼種や継ぎ目スラブなどのようにスラブの鋼成分が出鋼成分と異なる場合については、スラブにした後、必要に応じて鋼成分を分析する。
【００２５】
次に、熱間圧延前の材質演算ブロックで、過去の操業データの解析から求めた鋼成分、各製造工程の作業条件と材質特性値との関係および鋼成分や各製造工程の作業条件の変動量と材質特性値の変動量との関係に基いて、予め設定した材質演算プログラムに従って、オーダー標準の鋼成分の基準値とスラブの実績鋼成分との差を求め、材質特性値の基準値との差に換算する。
【００２６】
表２は、表１に示したオーダー標準に基き、出鋼、鋳造した鋼スラブの実績鋼成分とオーダー標準の鋼成分、および両者の差を示している。表３は、表２に示した鋼成分の差を材質特性値の差に換算した結果を示している。
【００２７】
また、表３には、受注規格の材質判定項目の優先度が、優先順に記載されている。Ｅｌ（伸び）、ｒ値（ランクフォード値）は、それぞれ順位１、順位２であり、これらは、順位３、順位４のＹＰ（降伏点）、ＴＳ（引張強度）に比べて、より重視すべき特性であることを示している。
【００２８】
【表２】
【表３】
次に、鋼成分差に起因する材質特性値の基準値とのずれを少なくするように、製造工程の作業条件を修正する。以下の説明では、表３に示した鋼成分差に起因する材質特性値の基準値とのずれがある鋼スラブについて、優先順位の高いＥｌとｒ値を優先してオーダー標準の基準値に近づけるように、熱延工程と冷間工程の作業条件を修正する場合を例に挙げて具体的に説明する。
【００３１】
先ず、熱間圧延前の製造条件再設定ブロックの製造条件再設定プログラムに従って、熱延工程の作業条件を修正して再設定する。熱延工程の各作業指示項目については、操業のし易さおよび製造コストを考慮して作業条件を変更する優先順序を定めた変更優先順位、および、操業上の支障がなく、製造コストの上昇を抑え、また材質以外の品質上の弊害の防止を考慮して定めた一定の操作範囲が設定されている。さらに、熱延工程の作業条件の変更量に対する材質特性値の変化量も決定できるようになっている。
【００３２】
変更優先順位の最も高い作業指示項目について、予め設定した操作範囲内で作業条件を展開し、展開した各条件について材質特性値の変化量を算出する。展開した条件に材質特性値の基準値とのずれを十分少なくできるものがあれば、作業条件をその条件に修正する。
【００３３】
展開した条件に、材質特質の基準値とのずれを十分少なくできるものがない場合、最もずれを少なくできる条件に作業条件を修正し、引き続き、次の順位の作業指示項目について、同様に、作業条件を展開し、材質特性値の変化量を算出し、さらに作業条件修正後の材質特性値の基準値とのずれを算出する。
【００３４】
作業条件の修正は、上記のようにして算出した材質特性値の基準値とのずれが十分少なくなるまで続ける。作業条件の修正作業の途中で、算出した材質特性値の基準値とのずれが十分少なくなったら、それ以降の作業条件の修正を終了する。
【００３５】
熱延工程の作業条件を修正しても、算出した材質特性値と基準値とのずれが十分少なくならない場合、冷間圧延前の製造条件再設定ブロックで、さらに下工程の冷間工程の作業条件を修正する。
【００３６】
表４はオーダー標準の熱延指示項目と変更優先順位を示している。優先順位は、操業のし易さおよび製造コストを考慮して、巻取温度、仕上温度、スラブ加熱温度、熱延板板厚の順に設定されている。
【００３７】
【表４】
この優先順位に従って、図２に示すように、熱延工程の作業条件を順次修正する。まず優先順位が最も高い巻取温度について、オーダー標準の基準巻取温度を中心として例えば１０℃ピッチで展開する。展開レンジは、操業性、コスト、製品への材質以外の影響（粗大粒、スケール）を考慮して設定されている。次に、展開した各巻取温度について、材質（ここではＥｌとｒ値）への影響度を算出する。
【００３９】
当例では鋼成分のずれから換算したＥｌ、ｒ値のずれは、オーダー標準の基準値に対して、それぞれ−１．００％、−０．２０であったが、巻取温度を修正して２０℃アップすることによって、Ｅｌ、ｒ値はそれぞれ０．２０％、０．０４改善され、−０．８０％、−０．１６になる。
【００４０】
引き続き、変更優先順位に従って、順次、仕上温度、スラブ加熱温度、熱延板板厚について、オーダー標準の基準値を中心として予め設定した範囲内で展開し、材質基準値とのずれの改善を行うように熱延条件を修正する。
【００４１】
当例では、Ｅｌ、ｒ値のずれが、スラブ加熱温度を修正して８０℃低下することによって、それぞれ０．４０％、０．０８改善され、熱延板板厚を修正して０．４ｍｍ厚くすることによって、さらにｒ値が０．０６改善される。前記のように熱延工程の作業条件を修正した結果、最終的に、熱延工程では、Ｅｌ、ｒ値は、オーダー標準の基準値に対して、それぞれ−０．４０％、−０．０２まで改善される。
【００４２】
前記で修正、再設定した作業条件を熱延工程に指示し、熱延工程では、この指示にしたがって作業する。
【００４３】
熱間圧延後の材質演算ブロックで、前記で修正、再設定した熱延工程の作業条件と実績熱延作業条件を比較し、両者の差に基く材質特性値のずれを算出し、熱延工程を終えた時点の材質特性値のオーダー標準の基準値からのずれを再び算出する。
【００４４】
表５は、修正した熱延指示条件と実績熱延作業条件を比較した表である。スラブ加熱温度が予定（修正温度）に対して、２０℃高くなっている。この変動分を材質変動に換算し、先の熱延工程における材質の改善量に合算して、材質特性値の基準値に対するずれを算出すると、表６に示すように、Ｅｌ、ｒ値は、オーダー標準の基準値に対して、それぞれ−０．５０％、−０．０４である。
【００４５】
【表５】
【表６】
熱延工程を終えた後に算出した材質特性値とオーダー標準の基準値にずれがなければ、冷間工程の作業条件を修正する必要がない。しかし、表６のように、オーダー標準の基準値との間にずれがある場合には、冷間工程において、そのずれをゼロに近づけるように、冷間圧延前の製造条件再設定ブロックで、予め設定された冷間工程製造条件再設定プログラムに従って、冷間工程の作業条件を修正し、再設定する。
【００４８】
冷間工程の作業指示項目についても、熱間工程の場合と同様に、操業のし易さおよび製造コストを考慮して作業条件を変更する優先順序を定めた変更優先順位、および、操業上の支障がなく、製造コストの上昇を抑え、また材質以外の品質上の弊害の防止を考慮して定めた一定の操作範囲が設定されている。さらに、熱延工程の作業条件の変更量に対する材質特性値の変化量も決定できるようになっている。
【００４９】
冷間工程の作業条件の修正についても、熱間工程の場合と同様に、変更優先順位の最も高い作業指示項目から、順次、順位の低い作業指示項目についてついて、作業条件を修正し、材質特性値の変化量を算出して、材質特性値の基準値とのずれを算出する。冷間工程の作業条件の修正は、上記のようにして算出した材質特性値の基準値とのずれが十分少なくなるまで続ける。作業条件の修正作業の途中で、算出した材質特性値の基準値とのずれが十分少なくなったら、それ以降の作業条件の修正を終了する。
【００５０】
表７は、オーダー標準の冷間作業指示項目および変更優先順位を示している。優先順位は、操業のし易さおよび製造コストを考慮して、スキンパスミル伸長率、焼鈍温度、ライン速度、焼き入れ開始温度、冷却速度の順に設定されている。
【００５１】
【表７】
この優先順位に従って、図３に示すように、冷間工程の作業条件を順次修正する。まずスキンパスミル伸長率についてオーダー標準を中心として例えば０．２％ピッチで展開する。展開レンジは、操業性、コスト、製品への材質以外の影響を考慮して予め設定された一定の範囲内にある。次に、展開した各スキンパスミル伸長率について、材質への影響度を算出する。
【００５３】
熱延工程では、Ｅｌ、ｒ値をオーダー標準の基準値に対して、それぞれ−０．５０％、−０．０４まで改善されていたが、冷間工程では、スキンパスミル伸長率を修正して０．４％ダウンすることによって、Ｅｌが０．０４％改善される。
【００５４】
次に、同様にして、焼鈍温度について、オーダー標準の基準値を中心として条件を展開し、材質への影響度を算出したところ、焼鈍温度を修正して２０℃上昇することによって、Ｅｌ、ｒ値が、それぞれ０．５０％、０．１０改善されて、オーダー標準の基準値に対して、それぞれ＋０．０４％、＋０．０６になった。Ｅｌ、ｒ値が所定の基準値を上回るレベルになったので、変更優先順位が３のライン速度以降の作業条件の修正は行わない。
【００５５】
前記で修正した作業条件を再設定し、冷間工程に指示し、冷間工程ではこの指示に従って作業する。
【００５６】
前記のようにして、各製造工程の作業条件を修正、再設定し、この再設定した作業条件に従って作業することによって、材質特性値のばらつきを少なくでき、また所望の材質にすることができる。
【００５７】
また、作業条件の変更に際して、操業性、製造コスト面で有利な作業指示項目の作業条件を優先的に変更し、また、条件変更は、操業のし易さと製造コスト、材質以外の品質面の弊害の発生を防止できるような範囲内で行われるので、操業上の支障を防止でき、製造コストの上昇を抑制でき、品質面の弊害の発生を防止できる。
【００５８】
なお、前記した説明では、鋼成分差に起因する材質特性値の基準値とのずれを少なくするために、熱延工程の作業条件を修正、再設定し、さらに熱延工程の実績作業条件を反映して、冷間工程の作業条件を修正、再設定したが、熱延工程と冷間工程の全体で優先順位を設定し、この優先順位にしたがって、全体の工程の作業条件を修正、再設定し、熱延工程では前記で再設定した作業条件に基いて作業し、熱延工程の実績作業条件に基いて冷間工程の作業条件を再度修正し、再度設定しなおしてもよい。また、可能な場合には、冷間工程の作業条件だけを再設定してもよい。
【００５９】
また、本発明においては、オーダー標準の材質特性値に許容範囲を設定し、各製造工程の作業条件を修正しても、修正後の材質特性値の予測値が前記許容範囲を外れる場合、予定した作業を一旦中止するようにしてもよい。
【００６０】
具体的には、実績鋼成分に基いて、熱延工程の作業条件を修正し、算出した材質特性値と基準値とのずれを少なくできない場合、引き続き、下工程の冷間工程の作業条件を修正して、最終製品の材質特性値の予測値を算出する。算出した予測値が許容範囲を外れる場合、熱延工程への装入を中止する。また、熱延工程を終えた時点で、実績熱延条件に基いて、冷間工程の作業条件を修正し、最終製品の材質特性値の予測値を算出する。算出した予測値が許容範囲を外れる場合、冷間工程への装入を中止する。このようにすることによって、材質不良材の製造を未然に防止できるとともに、客先要求を満足するスラブの再要求をすみやかに行うことができ、納期後れも防止できるようになる。
【００６１】
【発明の効果】
本発明によれば、鋼成分や各製造工程の製造条件が変動しても、材質特性値のばらつきを小さくでき、また所望の材質の冷延鋼帯を製造できるようになる。また、その際、操業上の支障、製造コストの上昇、品質面の弊害の発生を防止できる。
【図面の簡単な説明】
【図１】本発明における作業指示情報の指示、変更フローの要部を示すフローチャート。
【図２】本発明の実施の形態で説明した熱延工程の作業条件の修正手順を説明する図。
【図３】本発明の実施の形態で説明した冷間工程の作業条件の修正手順を説明する図。
【図４】従来技術の作業指示フローを示すフローチャート。
【図５】 従来技術の後工程の作業条件の変更方法を示すフローチャート。
【図６】図５に示したフローチャートの材質判定ＦＦ処理の内容を説明する図。[0001]
BACKGROUND OF THE INVENTION
The present invention is a cold-rolled steel strip that can reduce variations in material property values by changing the manufacturing conditions in the lower process even if the manufacturing conditions in steelmaking, hot rolling and cold processes (including plating processes) fluctuate. The present invention relates to a method for producing (including molten plated steel sheet, electroplated steel sheet, coated steel sheet, tin steel sheet, electromagnetic steel sheet, etc.).
[0002]
[Prior art]
In steel production, when producing a cold-rolled steel strip of a specified material through steelmaking, hot-rolling, and cold processes, first of all, before the start of production so as to satisfy the product specifications from the customer, an order is received. Set production specifications for each process such as steel grade, steel composition, slab heating temperature, hot rolling temperature, winding temperature, cold rolling rate, annealing temperature, skin pass mill elongation rate (hereinafter referred to as order standard). . Next, before the material is charged into each process, the manufacturing specifications are transmitted to a computer that supervises the process or an operator is instructed to perform the manufacturing.
[0003]
FIG. 4 is a flowchart showing an example of the processing flow of the prior art, and shows a case where a cold-rolled steel sheet is manufactured through a continuous annealing process. In order to produce products required by customers, order standards such as steel grade, steel composition and manufacturing conditions are set based on order information, and the order standards are stored in a plan information database (plan DB). Information (actual product information) regarding the steel type actually used and actual operating conditions is retained in a database (actual product DB) of actual product information.
[0004]
Usually, there is a slight difference between the actual steel composition and the steel composition of the standard production specifications. This difference is not reflected in the work instruction in the subsequent process. Moreover, the actual production conditions in the steelmaking and hot rolling processes also deviate from the standard production specifications. Due to the difference or deviation from the production specifications of these order standards, there is a problem that the deviation of the material characteristic value becomes large, and a final product having a desired material characteristic value cannot be obtained.
[0005]
A method for improving the above problems is proposed in Japanese Patent Laid-Open No. 5-273199. In the proposal, as shown in FIG. 5, a hot rolling work instruction S209 is performed from the results of the steel output component value S201, the steelmaking performance S208, and the material determination FF process (S100).
[0006]
The contents of the material determination FF process are shown in FIG. In FIG. 6, five levels of post-process conditions from the hot rolling process to the cold process are set in the material determination FF table S205. In the determination formula coefficient reference value table S207, a material determination coefficient is set for each steel component and each work condition in the post-process of steelmaking.
[0007]
A material determination FF table is created using the material determination FF table S205 and the determination formula coefficient reference value table S207 based on the steel output component information and the actual steelmaking results (S103), and the material determination reference is based on the material determination reference value table S206 and the like. A value is set (S106), and an estimated test value corresponding to each level of the post-process conditions is calculated (S108). Next, for each of all the material test items, the difference between the estimated test value corresponding to the five-level post-process conditions and the target value of the material determination reference value is obtained as a material determination result together with the priority (S110). The post-process condition with the highest priority in the material determination result is adopted as the post-process condition (S111), and a hot rolling work instruction is given as shown in FIG. 5 (S209).
[0008]
In addition, as shown in FIG. 5, a material determination FF using a coil management DB (S212) that stores a hot rolling record in place of the steel output component information S201 in the above procedure, as shown in FIG. Processing is performed (S211), and a cold work instruction is issued (S213).
[0009]
As described above, the condition of the highest priority level is adopted as the post-process condition, and since the post-process is manufactured under this condition, the material is uniform and the desired product can be manufactured. Yes.
[0010]
[Problems to be solved by the invention]
In order for the proposal to achieve the desired effect, it is necessary that at least one of the five levels of post-process conditions set for calculating the estimated test value is set to an optimum condition for obtaining a desired material. It is essential. However, the publication does not describe at all what conditions to set the five levels of conditions, and the optimum conditions for obtaining the desired material are selected for the set five levels of conditions. There is no guarantee that
[0011]
Therefore, the above proposal has a problem that even if the material can be made uniform to some extent, it is not always guaranteed that a product of a desired material can be obtained.
[0012]
Moreover, the steel component of a slab may become different from the steel output component, such as pickup of [C] and [N] in the steel during continuous casting after steel output. For steel types where the amount of [C] or [N] in the steel greatly affects the material, such as extremely low carbon steel, even if the estimated test value is calculated based on the steel output component, the accuracy of the calculated test value is Remarkably inferior. Therefore, in the above-mentioned proposal for calculating the estimated test value based on the steel output component information, the material quality is uniform for the steel types in which the pick-up of [C] and [N] in the steel is a problem, such as extremely low carbon steel. In addition, the effect of making a desired material cannot be expected.
[0013]
The present invention has been made in consideration of the above-mentioned problems, and it is an object of the present invention to produce a cold-rolled steel sheet or a hot-dip galvanized steel sheet having a small material characteristic value variation or a desired material characteristic value.
[0014]
[Means for Solving the Problems]
The means of the present invention for solving the above-described problems is as follows. (1) Steel manufacturing, hot rolling, and cold manufacturing processes (including plating processes) are performed to manufacture a cold-rolled steel strip of a predetermined material. In order to bring the material property value closer to the target value, based on the actual steel composition information, the hot rolling process is performed according to the change priority order determined in consideration of operability and operation cost based on the work conditions of each preset manufacturing process. , Coiling temperature, finishing temperature, slab heating temperature, hot-rolled sheet thickness, and / or cold process, skin pass mill elongation rate, annealing temperature, line speed, quenching start temperature, cooling speed, It is characterized in that cold rolled steel strip is manufactured based on the reset working conditions in order to make corrections and reset sequentially within a certain operating range determined taking into consideration the quality effects other than operability, manufacturing cost and material. Of cold-rolled steel strips with less variation in material property values (2) When manufacturing a cold-rolled steel strip of a predetermined material through each of the manufacturing processes of (2) steelmaking, hot rolling, and cold processes (including plating processes), the material property value is brought close to the target value. In addition, based on the actual steel composition information, the hot rolling process is performed at the coiling temperature, finishing temperature, slab according to the change priority order determined in consideration of operability and operating cost. In the order of heating temperature, hot-rolled sheet thickness and / or cold process, skin pass mill elongation rate, annealing temperature, line speed, quenching start temperature, cooling speed, in order of operability, manufacturing cost, and materials other than materials Corrected and reset in order within a certain operating range determined in consideration of quality influence, the hot rolling process works under the reset working conditions, and further reflects the actual working conditions of the upper process of the manufacturing process The preset work conditions for the lower process According to the changed priority order determined in consideration of sex and operating costs, the cold process, skin pass mill elongation, annealing temperature, line speed, quenching starting temperature, in the order of the cooling rate, operability, production cost, other than the material Material property values characterized by manufacturing cold-rolled steel strips based on working conditions re-corrected and re-set in order within a fixed operating range determined in consideration of quality effects. This is a method of manufacturing a cold-rolled steel strip with little variation in the thickness of the steel sheet.
[0015]
(Function)
Based on the actual steel composition, grasp the deviation of the component from the standard steel component of the order standard, and modify the manufacturing process work conditions to reduce the deviation of the material property value from the target value based on this deviation. Then, the deviation of the actual work condition in the upper process of the manufacturing process from the standard manufacturing specification is reflected in the work condition of the lower process to reduce the deviation of the material property value from the target value. Thus, the variation in the material property value of the cold-rolled steel strip manufactured under the modified work condition can be reduced or a desired material property value can be obtained.
[0016]
In addition, the modification of the working conditions of each manufacturing process is performed in accordance with the operation order determined in consideration of operability and manufacturing cost, and within a certain operating range determined in consideration of quality effects other than operability, manufacturing cost and material. Therefore, it is less likely that operations will be hindered, production costs will increase, and adverse effects on quality will not occur due to the modification of work conditions.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described.
FIG. 1 is a flowchart showing main processing portions of the present invention when a cold-rolled steel sheet is manufactured through a continuous annealing process. In order to create the products required by customers, the steel condition (steel component), slab heating temperature, heat, etc. based on the order information for each order according to the manufacturing condition setting program set in advance in the manufacturing condition setting block. Manufacturing specifications such as hot rolling temperature, winding temperature, rolling rate, annealing temperature, skin pass mill elongation rate, etc. are set as order standards.
[0018]
Further, in the order standard, a material determination item and its reference value, an allowable range thereof, a priority order of material determination, and the like are set according to the order standard. The order standard is stored in a plan information database (plan DB).
[0019]
Table 1 is an example of an order standard, in which reference values for steel components and reference work conditions for each manufacturing process are described.
[0020]
[Table 1]
The required steel plate is manufactured by instructing each manufacturing process on the steel components and work conditions based on the order standard. Information (actual product information) regarding the steel type actually used and actual operating conditions is retained in a database (actual product DB) of actual product information.
[0022]
The desired material can be obtained if it can be manufactured with steel components and working conditions as ordered. However, there are many cases that deviate from this order standard in actual operation. In the present invention, in order to reduce the variation in material property values, the work conditions of the manufacturing process are corrected in consideration of the deviation from the order standard of the steel components, and the deviation of the actual work condition in the upper process from the order standard. Correct and reflect the work conditions in the lower process. This point will be specifically described below.
[0023]
In FIG. 1, the planned hot rolling conditions, the planned annealing conditions, etc. are the conditions set in the order standard, and the corrected hot rolling conditions, the corrected annealing conditions, etc. are based on the actual steel composition, the actual working conditions, etc. This shows the set manufacturing conditions.
[0024]
First, in accordance with the set order standard, a work instruction for the steel making process is performed. In the steel making process, in accordance with this instruction, steel having a predetermined component composition is produced and made into a slab. If the steel composition of the slab is different from the steel composition, such as steel grades or seam slabs, where the pickup of [C] and [N] in the steel during casting is a problem, such as extremely low carbon steel After that, the steel components are analyzed as necessary.
[0025]
Next, in the material calculation block before hot rolling, the steel composition obtained from the analysis of past operation data, the relationship between the work condition of each manufacturing process and the material property value, and the fluctuation of the steel composition and the working condition of each manufacturing process Based on the relationship between the amount and the fluctuation amount of the material property value, the difference between the standard value of the steel component of the order standard and the actual steel component of the slab is obtained according to a preset material calculation program, and the reference value of the material property value Convert to the difference.
[0026]
Table 2 is based on the order standard shown in Table 1, and shows the actual steel composition of the steel output and the cast steel slab, the steel composition of the order standard, and the difference between the two. Table 3 shows the result of converting the difference in steel components shown in Table 2 into the difference in material property values.
[0027]
Table 3 lists the priorities of the material determination items of the order specification in order of priority. El (elongation) and r value (Rankford value) are
[0028]
[Table 2]
[Table 3]
Next, the working conditions of the manufacturing process are corrected so as to reduce the deviation from the reference value of the material characteristic value due to the difference in steel components. In the following description, with respect to a steel slab having a deviation from the reference value of the material property value due to the difference in steel components shown in Table 3, the higher priority El and r values are preferentially brought closer to the reference standard reference value. Thus, the case where the working conditions of the hot rolling process and the cold process are corrected will be described as an example.
[0031]
First, according to the manufacturing condition resetting program of the manufacturing condition resetting block before hot rolling, the working conditions of the hot rolling process are corrected and reset. For each work instruction item in the hot rolling process, there is no change in the priority order in which the priority order for changing the work conditions in consideration of the ease of operation and the manufacturing cost, and there is no operational trouble, and the manufacturing cost rises. In addition, a certain operation range is set which is determined in consideration of preventing the adverse effects on quality other than the material. Furthermore, the amount of change in the material characteristic value with respect to the amount of change in the working conditions of the hot rolling process can also be determined.
[0032]
For the work instruction item having the highest change priority, the work condition is developed within a preset operation range, and the change amount of the material characteristic value is calculated for each developed condition. If any of the developed conditions can sufficiently reduce the deviation of the material characteristic value from the reference value, the work condition is corrected to that condition.
[0033]
If none of the developed conditions can sufficiently reduce the deviation from the standard value of the material characteristics, modify the work condition to the condition that can minimize the deviation, and continue to work on the work order items of the next rank in the same way. The conditions are expanded, the amount of change in the material property value is calculated, and the deviation from the reference value of the material property value after the working condition is corrected is calculated.
[0034]
The modification of the working condition is continued until the deviation from the reference value of the material characteristic value calculated as described above is sufficiently reduced. If the deviation of the calculated material property value from the reference value becomes sufficiently small during the work condition correction work, the subsequent work condition correction is terminated.
[0035]
If the deviation between the calculated material property value and the reference value is not sufficiently reduced even if the hot rolling process conditions are modified, the cold process work in the lower process is performed in the manufacturing condition reset block before cold rolling. Correct the condition.
[0036]
Table 4 shows the order standard hot rolling instruction items and change priorities. The priorities are set in the order of the winding temperature, the finishing temperature, the slab heating temperature, and the hot-rolled sheet thickness in consideration of the ease of operation and the manufacturing cost.
[0037]
[Table 4]
According to this priority order, as shown in FIG. 2, the working conditions of the hot rolling process are sequentially corrected. First, the winding temperature with the highest priority is developed at a pitch of 10 ° C., for example, with the reference standard reference winding temperature as the center. The development range is set in consideration of operability, cost, and effects (coarse grains, scale) other than the material on the product. Next, for each developed winding temperature, the degree of influence on the material (here, El and r value) is calculated.
[0039]
In this example, the deviations of El and r values converted from the deviations of the steel components were -1.00% and -0.20, respectively, with respect to the standard value of the order standard. By increasing the temperature by 20 ° C., the El and r values are improved by 0.20% and 0.04, respectively, to −0.80% and −0.16.
[0040]
Subsequently, according to the change priority, the finish temperature, slab heating temperature, and hot-rolled sheet thickness are developed within a preset range centered on the standard value of the order standard, and the deviation from the material standard value is improved. Modify the hot rolling conditions as follows.
[0041]
In this example, the deviation of El and r values is improved by 0.40% and 0.08 respectively by correcting the slab heating temperature and decreasing by 80 ° C., and the hot-rolled sheet thickness is corrected to 0.4 mm. By increasing the thickness, the r value is further improved by 0.06. As a result of correcting the working conditions of the hot rolling process as described above, finally, in the hot rolling process, the El and r values are −0.40% and −0.02 with respect to the standard value of the order standard, respectively. Will be improved.
[0042]
The work conditions corrected and reset as described above are instructed to the hot rolling process, and the hot rolling process works according to this instruction.
[0043]
In the material calculation block after hot rolling, the working conditions of the hot rolling process corrected and reset as described above are compared with the actual hot rolling working conditions, and the deviation of the material property value based on the difference between the two is calculated. The deviation of the material property value from the reference value of the order standard at the time when the process is finished is calculated again.
[0044]
Table 5 is a table comparing the corrected hot rolling instruction conditions with the actual hot rolling work conditions. The slab heating temperature is 20 ° C. higher than planned (corrected temperature). Converting this fluctuation into material fluctuation, adding it to the amount of material improvement in the previous hot rolling process, and calculating the deviation of the material characteristic value from the reference value, as shown in Table 6, El and r values are: They are -0.50% and -0.04, respectively, with respect to the reference value of the order standard.
[0045]
[Table 5]
[Table 6]
If there is no deviation between the material property value calculated after the hot rolling process and the standard value of the order standard, it is not necessary to modify the working conditions of the cold process. However, as shown in Table 6, when there is a deviation from the standard value of the order standard, in the cold process, in the manufacturing condition reset block before cold rolling, so that the deviation is close to zero, According to a preset cold process manufacturing condition reset program, the cold process work conditions are corrected and reset.
[0048]
As for the work instruction items in the cold process, as in the case of the hot process, a change priority order that determines the priority order for changing the work conditions in consideration of the ease of operation and the manufacturing cost, and the operational There is no hindrance, a certain operating range is set that is set in consideration of preventing an increase in manufacturing cost and preventing adverse effects on quality other than materials. Furthermore, the amount of change in the material characteristic value with respect to the amount of change in the working conditions of the hot rolling process can also be determined.
[0049]
Regarding the modification of the work conditions for the cold process, as in the case of the hot process, the work conditions for the work instruction items with the lowest priority are revised in order from the work instruction item with the highest priority for change. A change amount of the value is calculated, and a deviation of the material characteristic value from the reference value is calculated. The modification of the working condition of the cold process is continued until the deviation from the reference value of the material characteristic value calculated as described above is sufficiently reduced. If the deviation of the calculated material property value from the reference value becomes sufficiently small during the work condition correction work, the subsequent work condition correction is terminated.
[0050]
Table 7 shows the order standard cold work instruction items and the change priority. The priorities are set in the order of skin pass mill elongation rate, annealing temperature, line speed, quenching start temperature, and cooling speed in consideration of ease of operation and manufacturing cost.
[0051]
[Table 7]
According to this priority order, as shown in FIG. 3, the working conditions of the cold process are sequentially corrected. First, the skin pass mill elongation rate is developed, for example, at a pitch of 0.2% centering on the order standard. The development range is within a certain range set in advance in consideration of the operability, cost, and effects other than the material on the product. Next, the degree of influence on the material is calculated for each developed skin pass mill elongation rate.
[0053]
In the hot rolling process, the El and r values were improved to -0.50% and -0.04, respectively, with respect to the standard value of the order standard. In the cold process, the skin pass mill elongation rate was corrected. By reducing 0.4%, El is improved by 0.04%.
[0054]
Next, in the same manner, the conditions for the annealing temperature were developed around the reference value of the order standard, and the influence on the material was calculated. By correcting the annealing temperature and increasing it by 20 ° C., El, r The values were improved by 0.50% and 0.10, respectively, to + 0.04% and +0.06, respectively, with respect to the standard value of the order standard. Since the El and r values have exceeded the predetermined reference values, the work conditions after the line speed with the change priority of 3 are not corrected.
[0055]
The work conditions corrected as described above are reset, and a cold process is instructed. In the cold process, the work is performed according to this instruction.
[0056]
As described above, the work conditions of each manufacturing process are corrected and reset, and the work is performed according to the reset work conditions, whereby variation in material characteristic values can be reduced and a desired material can be obtained.
[0057]
In addition, when changing the work conditions, the work conditions of work instruction items that are advantageous in terms of operability and manufacturing cost are preferentially changed. Since it is performed within a range that can prevent the occurrence of adverse effects, operational troubles can be prevented, an increase in manufacturing costs can be suppressed, and adverse effects on quality can be prevented.
[0058]
In the above description, in order to reduce the deviation from the reference value of the material property value due to the steel component difference, the working conditions of the hot rolling process are corrected and reset, and the actual working conditions of the hot rolling process are further set. Reflecting this, the working conditions of the cold process were corrected and reset, but priorities were set for the entire hot rolling process and cold process, and the working conditions of the entire process were corrected and reset according to this priority. In the hot rolling process, the work may be performed based on the work conditions reset as described above, the work conditions of the cold process may be corrected again based on the actual work conditions of the hot rolling process, and may be set again. If possible, only the working conditions of the cold process may be reset.
[0059]
Further, in the present invention, if an allowable range is set for the material property value of the standard order and the work condition of each manufacturing process is corrected, the predicted value of the material property value after correction is out of the allowable range. The work performed may be temporarily stopped.
[0060]
Specifically, based on the actual steel composition, if the work conditions of the hot rolling process are corrected and the deviation between the calculated material property value and the standard value cannot be reduced, the work conditions of the cold process of the lower process are continued. Correct and calculate the predicted value of the material property value of the final product. When the calculated predicted value is out of the allowable range, the charging to the hot rolling process is stopped. Further, at the time when the hot rolling process is completed, based on the actual hot rolling conditions, the working conditions of the cold process are corrected, and the predicted value of the material property value of the final product is calculated. When the calculated predicted value is out of the allowable range, charging to the cold process is stopped. By doing so, it is possible to prevent the production of defective materials, and it is possible to promptly re-request slabs that satisfy customer requirements, and to prevent delays in delivery.
[0061]
【The invention's effect】
According to the present invention, even if the steel components and the manufacturing conditions of each manufacturing process fluctuate, the variation of the material characteristic value can be reduced, and a cold-rolled steel strip of a desired material can be manufactured. Further, at that time, it is possible to prevent operational troubles, an increase in manufacturing costs, and adverse effects on quality.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a main part of a work instruction information instruction and change flow according to the present invention.
FIG. 2 is a diagram for explaining a procedure for correcting the working conditions of the hot rolling process described in the embodiment of the present invention.
FIG. 3 is a diagram for explaining a procedure for correcting the working conditions of the cold process described in the embodiment of the present invention.
FIG. 4 is a flowchart showing a prior art work instruction flow.
FIG. 5 is a flowchart showing a method for changing a work condition in a post-process in the prior art.
6 is a diagram for explaining the contents of a material determination FF process in the flowchart shown in FIG. 5;
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35460797A JP4148551B2 (en) | 1997-12-24 | 1997-12-24 | Manufacturing method of cold-rolled steel strip with less variation in material property values |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35460797A JP4148551B2 (en) | 1997-12-24 | 1997-12-24 | Manufacturing method of cold-rolled steel strip with less variation in material property values |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11179410A JPH11179410A (en) | 1999-07-06 |
| JP4148551B2 true JP4148551B2 (en) | 2008-09-10 |
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| JP35460797A Expired - Fee Related JP4148551B2 (en) | 1997-12-24 | 1997-12-24 | Manufacturing method of cold-rolled steel strip with less variation in material property values |
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002161316A (en) * | 2000-11-21 | 2002-06-04 | Nkk Corp | Method for manufacturing material with predicting quality |
| JP3979023B2 (en) * | 2001-03-29 | 2007-09-19 | Ｊｆｅスチール株式会社 | Manufacturing method of high strength cold-rolled steel sheet |
| JP4187960B2 (en) * | 2001-11-05 | 2008-11-26 | Ｊｆｅスチール株式会社 | Material stabilization system |
| JP2005074448A (en) * | 2003-08-29 | 2005-03-24 | Jfe Steel Kk | Coil and its manufacturing method |
| JP2006239696A (en) * | 2005-02-28 | 2006-09-14 | Jfe Steel Kk | Method for reducing variance in quality of hot-rolled steel sheet |
| JP4580792B2 (en) * | 2005-03-17 | 2010-11-17 | 株式会社神戸製鋼所 | Material analysis method, material stabilization method and material stabilization apparatus for metal materials |
| JP4940957B2 (en) * | 2007-01-11 | 2012-05-30 | 東芝三菱電機産業システム株式会社 | Rolling line structure / material management system |
| WO2008099457A1 (en) * | 2007-02-09 | 2008-08-21 | Toshiba Mitsubishi-Electric Industrial Systems Corporation | Process line control unit and method of controlling the line |
| JP5803682B2 (en) * | 2011-01-26 | 2015-11-04 | Ｊｆｅスチール株式会社 | Cold rolled steel sheet manufacturing method |
| MA47360B1 (en) * | 2016-12-20 | 2023-06-28 | Arcelormittal | METHOD FOR MANUFACTURING A HEAT-TREATED STEEL SHEET |
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| JPH11179410A (en) | 1999-07-06 |
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