JP3765270B2

JP3765270B2 - Method and apparatus for manufacturing hot-dip metal strip

Info

Publication number: JP3765270B2
Application number: JP2001396575A
Authority: JP
Inventors: 宗浩石岡; 秀行高橋; 俊夫石井; 和久壁矢; 昭蒲; 洋一宮川
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2001-12-27
Filing date: 2001-12-27
Publication date: 2006-04-12
Anticipated expiration: 2021-12-27
Also published as: JP2003193212A

Description

【０００１】
【発明の属する技術分野】
本発明は、溶融めっき金属帯の製造方法及び製造装置に関する。
【０００２】
【従来の技術】
鋼帯などの金属帯を亜鉛、アルミニウム等の溶融金属中に連続して浸漬してその金属帯の表面にめっきを施して製造する溶融めっき金属帯の製造方法が知られている。
【０００３】
連続的に溶融めっき金属帯を製造する従来の装置の構成を図１２に示す。図１２において１は金属帯、２は溶融金属浴槽、３は溶融金属浴、４は方向転換ロールであるシンクロール、５はサポートロール、６はワイパであるガスワイピングノズル、７はスナウトである。
【０００４】
この装置を用いて、溶融亜鉛めっき鋼帯を製造する場合を例に挙げて説明する。この場合、溶融金属は亜鉛である。スナウト７から出た鋼帯１を、溶融金属浴槽２内の溶融金属浴３に連続的に引き込み、シンクロール４に巻掛けて通板方向を転換し、サポートロール５を通過後、溶融金属浴３から引き上げ、溶融金属浴３上に設置したガスワイピングノズル６から高圧ガスを吹き付けることにより、鋼帯１表面に余剰に付着した溶融亜鉛を払拭して所定のめっき付着量に調整して溶融亜鉛めっき鋼帯を製造する。
【０００５】
サポートロール５は、ガスワイピングノズル６部における鋼帯１の幅方向反り（Ｃ反り）を矯正し、鋼帯１幅方向の付着量ばらつきを少なくするために設置されている。サポートロール５は、鋼帯１を挟む両側に１本ずつ設置し、各サポートロール５ａ、５ｂの高さ方向位置をずらして配置する。そして上方に配置したサポートロール５ａをパスラインに接するように配置し、下方に設置したサポートロール５ｂを鋼帯１側に押し込み、鋼帯１に適量の変形を付与することによって、鋼帯１のＣ反りを矯正する。
【０００６】
しかし、サポートロール５ａ、５ｂによって鋼帯１のＣ反りを矯正すると以下の問題点がある。すなわち、サポートロール５ａ、５ｂは、溶融金属浴槽２側方の溶融金属浴面より高い位置に設置したモータ（図示なし）によってスピンドル（図示なし）を介して駆動されるため、モータ回転は等速であっても、サポートロール５ａ、５ｂは等速回転しない。その結果、サポートロール５ａ、５ｂの回転速度は、鋼帯速度と一致しないだけでなく、等速回転できないことによって、鋼帯１にチャターマーク状の付着量むらや後記するドロスがロール表面に付着すること等によって擦り疵が発生し、品質上の問題になることがある。
【０００７】
サポートロール５ａ、５ｂを回転駆動することによって発生する前記問題点を解決するためにサポートロール５ａ、５ｂをアイドル化（非駆動化）することも考えられる。この場合、サポートロール５ａ、５ｂの回転を確保するために、サポートロール５ｂの押し込み量を増加する必要がある。しかし、サポートロール５ｂの押込み量を増加することによって、浴面を出たところ（ガスワイピングノズル６部）における鋼帯１のＣ反りを適正に矯正することができなくなるため、鋼帯１幅方向の付着量のばらつきが大きくなるという問題がある。
【０００８】
また、図１２に示した装置を用いて溶融亜鉛めっき鋼帯を製造すると、鋼帯１から溶出した鉄（Ｆｅ）とめっき成分との金属間化合物であるドロス（いわゆるボトムドロス）１６が発生し、このドロス１６は溶融金属浴槽２底部に堆積し、堆積したドロス１６が巻き上げられて溶融金属浴３中を浮遊する。このドロス１６が鋼帯１に付着すると鋼帯１の表面品質を低下させ、プレス時等に欠陥を発生させるという問題がある。鋼帯通板速度を低下することで鋼帯１へのドロス付着が低減されるが、生産効率が低下するという問題がある。
【０００９】
【発明が解決しようとする課題】
本発明の目的は、前記事情を考慮して、浴中のサポートロールに起因するチャターマーク状の付着量むらや擦り疵の発生を防止でき、またガスワイピング部における金属帯の幅方向反りを防止して金属帯幅方向の付着量ばらつきを低減でき、さらに生産効率を低下させずに金属帯へのドロス欠陥の発生を防止できる溶融めっき金属帯の製造方法および製造装置を提供することにある。
【００１０】
【課題を解決するための手段】
上記課題を解決する本発明の手段は下記のとおりである。
【００１１】
（１）金属帯をめっき金属である溶融金属浴内に引き込み、前記金属帯に溶融金属を付着させる引込工程と、
前記溶融金属浴内に引き込まれた金属帯を囲むように形成された囲み部材により、前記溶融金属浴内が溶融金属の流動可能な状態で上部領域と下部領域に分割されており、前記金属帯は前記上部領域で方向転換ロールにより方向転換されるとともに、方向転換後には溶融金属浴でロールに接することなく溶融金属浴外へ引き上げられる引上工程と、
前記金属帯に付着した過剰の溶融金属を払拭するワイパによって、溶融金属の付着量を調整する調整工程と、
前記ワイパの直前又は直後で前記金属帯の形状を磁力により非接触で矯正する形状矯正工程と
を有するとともに、前記引き上げ工程の囲み部材は下記（イ）〜（ニ）のいずれかであることを特徴とする溶融めっき金属帯の製造方法。
（イ）金属帯引き上げ側の囲みは、金属帯がシンクロールから離れて通板される部分ではパスラインと略平行に構成され、該金属帯引き上げ側の囲み上端はシンクロール最上部より高く且つ浴面から１００ｍｍ以上となるように構成されている囲み部材。
（ロ）金属帯引き上げ側の囲みの上端外側に、溶融金属浴下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設されている囲み部材。
（ハ）金属帯引き上げ側の囲みの上端外側に、溶融金属浴の下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設されるとともに、さらに該巻き上げ防止板と浴面との間に随伴流の流れ方向を変更し、かつ随伴流が浴面を乱すことを防止するための整流板が浴面に略平行に付設されている囲み部材。
（ニ）金属帯引き上げ側の囲みは上方外側に向かって傾斜状に構成され、さらに前記金属帯引き上げ側の囲みとパスラインとの間に金属帯随伴流を金属帯から離れさせかつ随伴流が浴面を乱さないようにするための整流構造物が付設されるとともに、該整流構造物は、パスラインに対向する側がパスラインと略平行で、金属帯引き上げ側の囲みに対向する側が金属帯引き上げ側の囲みに略平行に構成されている囲み部材。
（２）前記（１）において、（ロ）又は（ハ）の囲み部材は、金属帯引き上げ側の囲みは、金属帯がシンクロールから離れて通板される部分ではパスラインと略平行に構成され、該金属帯引き上げ側の囲み上端はシンクロール最上部より高く且つ浴面から１００ｍｍ以上となるように構成されていることを特徴とする前記（１）に記載の溶融めっき金属帯の製造方法。
（３）前記（１）において、（ニ）の囲み部材は、金属帯引き上げ側の囲み上端外側に溶融金属浴下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設され、また前記整流構造物の上部は略水平に構成されるとともに、その金属帯引き上げ側の囲みに対向する側に略水平な整流板が付設されていることを特徴とする前記（１）に記載の溶融めっき金属帯の製造方法。
【００１２】
（４）前記上部領域で発生したドロスを含む溶融金属浴は、前記囲み部材の金属帯の溶融金属浴外への引き上げ側から前記下部領域に流出され、前記下部領域で、溶融金属浴に含まれるドロスが沈降除去されて溶融金属浴が清浄化され、清浄化された溶融金属浴は、前記囲み部材の金属帯の溶融金属浴への引き込み側から前記上部領域に導入されることを特徴とする前記（１）〜（３）のいずれかに記載の溶融めっき金属帯の製造方法。
【００１３】
（５）前記囲み部材は、溶融金属浴面下に設けられていることを特徴とする前記（１）〜（４）のいずれかに記載の溶融めっき金属帯の製造方法。
【００１４】
（６）前記方向転換ロールと前記囲み部材の最近接距離が５０ｍｍ以上４００ｍｍ以下であることを特徴とする前記（１）〜（５）のいずれかに記載の溶融めっき金属帯の製造方法。
【００１５】
（７）前記方向転換ロール最上部と溶融金属浴面との間隔が５０ｍｍ以上４００ｍｍ以下であることを特徴とする前記（１）〜（６）のいずれかに記載の溶融めっき金属帯の製造方法。
【００１６】
（８）前記方向転換ロールの外径はφ８５０ｍｍ以上であることを特徴とする前記（１）〜（７）のいずれかに記載の溶融めっき金属帯の製造方法。
【００１７】
（９）前記方向転換ロール下面と溶融金属浴底部の間隔は４００ｍｍ以上である（前記（６）の場合には４００ｍｍに囲み部材の厚さを加えた値を超えるものである）ことを特徴とする前記（１）〜（８）のいずれかに記載の溶めっき金属帯の製造方法。
【００１８】
（１０）金属帯をめっき金属である溶融金属の浴中に引き込むことにより溶融めっき金属帯を製造する装置において、
前記溶融金属を保持してその溶融金属を前記金属帯に付着させるとともに、前記溶融金属浴中にて前記金属帯を方向転換させる方向転換ロールを有するとともに、方向転換後には前記金属帯に接するロールを有さない溶融金属浴槽と、
前記溶融金属浴槽内に、溶融金属浴内に引き込まれた金属帯を囲み、且つ前記溶融金属浴内が溶融金属の流動可能な状態で上部領域と下部領域に分割するように形成され、前記上部領域で方向転換ロールにより方向転換された金属帯が溶融金属浴外に引き上げられるように形成された囲み部材と、
前記金属帯に付着した過剰の溶融金属を払拭してその付着量を調整するワイパと、
前記ワイパの直前又は直後で前記金属帯の形状を磁力により非接触で矯正する形状矯正装置と
を備えるとともに、前記囲み部材は下記（イ）〜（ニ）のいずれかであることを特徴とする溶融めっき金属帯の製造装置。
（イ）金属帯引き上げ側の囲みは、金属帯がシンクロールから離れて通板される部分ではパスラインと略平行に構成され、該金属帯引き上げ側の囲み上端はシンクロール最上部より高く且つ浴面から１００ｍｍ以上となるように構成されている囲み部材。
（ロ）金属帯引き上げ側の囲みの上端外側に、溶融金属浴下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設されている囲み部材。
（ハ）金属帯引き上げ側の囲みの上端外側に、溶融金属浴の下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設されるとともに、さらに該巻き上げ防止板と浴面との間に随伴流の流れ方向を変更し、かつ随伴流が浴面を乱すことを防止するための整流板が浴面に略平行に付設されている囲み部材。
（ニ）金属帯引き上げ側の囲みは上方外側に向かって傾斜状に構成され、さらに前記金属帯引き上げ側の囲みとパスラインとの間に金属帯随伴流を金属帯から離れさせかつ随伴流が浴面を乱さないようにするための整流構造物が付設されるとともに、該整流構造物は、パスラインに対向する側がパスラインと略平行で、金属帯引き上げ側の囲みに対向する側が金属帯引き上げ側の囲みに略平行に構成されている囲み部材。
（１１）前記（１０）において、（ロ）又は（ハ）の囲み部材は、金属帯引き上げ側の囲みは、金属帯がシンクロールから離れて通板される部分ではパスラインと略平行に構成され、該金属帯引き上げ側の囲み上端はシンクロール最上部より高く且つ浴面から１００ｍｍ以上となるように構成されていることを特徴とする前記（１０）に記載の溶融めっき金属帯の製造装置。
（１２）前記（１０）において、（ニ）の囲み部材は、金属帯引き上げ側の囲み上端外側に溶融金属浴下部領域で沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板が付設され、また前記整流構造物の上部は略水平に構成されるとともに、その金属帯引き上げ側の囲みに対向する側に略水平な整流板が付設されていることを特徴とする前記（１０）に記載の溶融めっき金属帯の製造装置。
【００１９】
（１３）前記囲み部材は、前記金属帯の溶融金属浴外への引き上げ側の囲み部側から、前記上部領域で発生したドロスを含む溶融金属浴が前記下部領域に流出され、また前記金属帯の溶融金属浴への引き込み側の囲み部側から、前記下部領域でドロスが沈降除去されて清浄化された溶融金属浴が前記上部領域に導入されるように構成されていることを特徴とする前記（１０）〜（１２）のいずれかに記載の溶融めっき金属帯の製造装置。
【００２０】
（１４）前記囲み部材は、溶融金属浴面下に設けられていることを特徴とする前記（１０）〜（１３）のいずれかに記載の溶融めっき金属帯の製造装置。
【００２１】
（１５）前記方向転換ロールと前記囲み部材の最近接距離が５０ｍｍ以上４００ｍｍ以下であることを特徴とする前記（１０）〜（１４）のいずれかに記載の溶融めっき金属帯の製造装置。
【００２２】
（１６）前記方向転換ロール最上部と溶融金属浴面との間隔が５０ｍｍ以上４００ｍｍ以下であることを特徴とする前記（１０）〜（１５）のいずれかに記載の溶融めっき金属帯の製造装置。
【００２３】
（１７）前記方向転換ロールの外径がφ８５０ｍｍ以上であることを特徴とする前記（１０）〜（１６）のいずれかに記載の溶融めっき金属帯の製造装置。
【００２４】
（１８）前記方向転換ロール下面と前記溶融金属浴槽底部の間隔は４００ｍｍ以上である（前記（１５）の場合には４００ｍｍに囲み部材の厚さを加えた値を超えるものである）ことを特徴とする前記（１０）〜（１７）のいずれかに記載の溶融めっき金属帯の製造装置。
【００３１】
【発明の実施の形態】
以下、本発明に至った経緯とともに、本発明について詳しく説明する。
本発明者らは本発明の課題を解消する新しい溶融めっき金属帯の製造方法を開発するため、先ず浴中のサポートロール５に着目した。サポートロール５の主な機能は金属帯幅方向反り矯正機能である。
【００３２】
図１は、金属帯１幅方向反り発生機構を説明する図である。金属帯幅方向反りは主にシンクロール４において金属帯１が曲げと曲げ戻しを受けることによって発生すると考えられる。シンクロール４に巻きついて接触している位置Ａでは、平面ひずみ変形となり、金属帯１に発生する応力は、金属帯通板方向および金属帯幅方向ともに、シンクロール４と接触している側に圧縮応力、その反対側に引張応力となり、金属帯幅方向反りの基本となる応力分布になる。シンクロール４に近く、比較的曲率半径の大きな位置Ｂにおいても、ほぼ平面ひずみ状態が保たれ、位置Ａにおいて塑性変形をしているために、位置Ａとは逆の応力分布、すなわちシンクロール４と接触している側に引張応力、その反対側に圧縮応力となる。曲率半径がほぼ０の位置Ｃにおいては、面内変形に対する拘束はなく、基本的には位置Ａで受けた変形が存在しやすい形状、すなわち金属帯幅方向に上に凸の状態となると考えられる。
【００３３】
このようにして金属帯１に反りが発生した場合、ガスワイピングノズル６部において、金属帯１とガスワイピングノズル６と間隔が幅方向で一定でなくなる結果、金属帯１幅方向に付着量のばらつきが生ずることになる。
【００３４】
また、金属帯１に反りが発生している場合は、金属帯１とガスワイピングノズル６との接触を避けるために、金属帯１とガスワイピングノズル６の間隔を狭めることが制限される。この結果、所望の溶融金属払拭能力を確保するためにはガスワイピングノズル６のガス圧力を高めなければならず、これが時としてガスワイピング時に激しく飛び散った溶融金属が金属帯１に付着することにより発生するスプラッシュと呼ばれる欠陥の原因となることが知られている。
【００３５】
そこで、浴中のサポートロール５を用いてシンクロール４で発生した反りを矯正する。
【００３６】
図２は、図１２に示した装置におけるサポートロール５の反り矯正機能を説明する図である。シンクロール４によって金属帯１は鉛直方向に方向転換されて通板される。サポートロール５ａはパスライン上で金属帯１と接する位置に設けられ、サポートロール５ａに対して所定距離だけ下方に配置されたサポートロール５ｂはこのパスラインに対して所定量Ｌだけ金属帯１を押し込む位置に配置される。
【００３７】
前述のように金属帯１はシンクロール４による曲げと曲げ戻しに起因する反りが発生しているが、サポートロール５ｂを用いて押し込み量Ｌを適切に調整することで、金属帯１に逆方向の曲げを加えて反りを矯正するものである。
【００３８】
このように浴中のサポートロール５は主に金属帯１幅方向の反り矯正のために、数十年の長きに渡って使用された設備であって、前記したように金属帯１にチャターマーク状の付着量むらや擦り疵を発生するという問題に加えて、さらにサポートロール５の定期的な手入れや交換のために設備停止が必要となり、操業効率を低下させてしまうという問題があるにも係わらず、その実績から溶融めっき金属帯製造ラインにとっては必須の設備であると考えられている。
【００３９】
これらの問題は浴中にサポートロール５がなければ発生しないものであるため、本発明者らは溶融めっき金属帯製造プロセスからサポートロール５を外すことの可否について検討を行った。
【００４０】
先ず、浴中のサポートロール５を取り外すことによる金属帯品質への悪影響がないかどうかを検証した。これは、製造現場においては、サポートロール５には前述の機能の他に、溶融金属浴３中のドロスなどの異物を金属帯１に付着しにくくする異物除去機能があるため、サポートロール５を除去することにより金属帯１の欠陥発生を増加させることになるとの通説があるためである。
【００４１】
この検証は溶融金属浴３を模擬する実験装置を製作し、その中の流れの挙動を観察することで行った。実験装置は、溶融金属の代わりに水を用い、その中にシンクロール４とサポートロール５を模したロールを配置し、さらに金属帯１を模したエンドレスベルトを配して構成し、実際の溶融金属浴中のロール周りとレイノズル数やフルード数が同等になるようにロール径やロール回転数を設定して、流体力学的に溶融金属浴中の挙動を模擬できるようにした。流れを観察するためのトレーサとしてアルミ粉を添加して実験を行った。
【００４２】
その結果、サポートロール５を模したロールにはベルトに付着した異物（アルミ粉）を剥がすような作用は観察されず、サポートロール５を模したロールは異物を押し付けるだけであった。この結果より、浴中のサポートロール５には通説で言われているような異物除去機能はなく、サポートロール５を除去してもそのことによって欠陥の発生が増加することはないものと判断した。また、実ラインで図１２に示した溶融めっき金属帯製造設備を用いてサポートロール５を使用しないで亜鉛めっき鋼帯を製造したところ、これによって亜鉛めっき鋼帯のドロス欠陥が増加しないことが確認された。
【００４３】
従って、サポートロール５を外すには金属帯１の幅方向の反り矯正機能が代替できれば良いことになる。
【００４４】
溶融めっき金属帯を対象とする場合は、反り矯正を行う手段は非接触式であることが望ましく、制御性の点から電磁石などの磁力を用いて金属帯の形状矯正を行うのが好適である。サポートロール５を取り外し、代わりに電磁石などの磁力を用いて金属帯１の形状矯正（Ｃ反り矯正）することによって、サポートロール５使用によって発生する前記問題点を全て解消できる。
【００４５】
また、本発明者等は、通常の溶融亜鉛めっき操業における溶融金属浴槽２内の溶融亜鉛の流れ、およびドロスの発生メカニズムとドロスの溶融金属浴槽２内での挙動を調査し、以下のことを確認した。
【００４６】
鋼帯１に付着して品質欠陥を発生させるドロス（いわゆるボトムドロス）１６は、溶融金属浴３中で、鋼帯１から溶出した鉄（Ｆｅ）とめっき成分との金属間化合物である。このドロスはめっき成分と鋼帯１から溶出した鉄との反応で生成するため、生成当初は微細である。この微細なドロスが鋼帯１に付着しても品質上の問題はない。
【００４７】
この微細なドロスは、鉄成分を含有し、密度が溶融金属浴３の密度に比べて高いため、溶融金属浴３中で沈降する。連続操業においては、このドロスは溶融金属浴槽２底部に沈降して堆積する。溶融金属浴槽２底部に堆積したドロスは、通板される鋼帯１の随伴流によって巻き上げられて浮上しやすい。堆積の過程あるいは浮上と沈降を繰り返している過程で、浴温変動や溶融金属浴成分変動などによって、微細なドロスは集合合体して大きなドロスになる。
【００４８】
この大きなドロス１６が通板される鋼帯１の随伴流によって巻き上げられて浴中を浮遊し、鋼帯１表面に付着する。鋼帯１表面に付着した大きなドロス１６は、鋼帯１の表面品質を劣化させる。鋼帯通板速度が高速であると、随伴流が大きくなり、ドロス１６が浮上しやすくなり、鋼帯１のドロス欠陥の発生が増加する。
【００４９】
鋼帯１のドロス欠陥の発生を防止するには、溶融金属浴槽２底部に堆積したドロス１６の巻き上げを防止することが必要であり、そのためには、鋼帯１の随伴流が溶融金属槽２底部にまで大きく影響することを防止することが必要である。またドロス１６が巻き上げられたとしても、巻き上げられたドロス１６が鋼帯１が通板される領域に移動できないようにすることも必要である。
【００５０】
係る観点から、溶融金属浴槽２の構造および溶融金属浴３の流れについて種々検討した結果、溶融金属浴槽２内に、溶融金属浴３内に引き込まれた鋼帯１を囲むように形成された囲み部材を設けて、前記溶融金属浴３内を溶融金属の流動可能な状態で上部領域と下部領域に分割し、上部領域では鋼帯１にめっきを行い、下部領域では上部領域で発生したドロスを含む溶融金属浴３からドロスを沈降除去して溶融金属浴３を清浄化するように上部領域と下部領域の機能を分けるとともに、下部領域で清浄化した溶融金属浴３を上部領域に導入することで鋼帯１のドロス欠陥の発生を低減できることを見出した。
【００５１】
本発明は上記知見に基づきなされたものである。
【００５２】
以下、本発明の実施の形態についてさらに説明する。尚、以下に説明する各実施の形態では金属帯の１具体例として鋼帯を念頭においている。また溶融めっき鋼帯は亜鉛めっき鋼帯であり、溶融金属は亜鉛である。
【００５３】
図３は本発明の第１の実施の形態の溶融めっき金属帯製造装置の構成を示す図である。本装置においては、図１２に示した従来の装置で浴中に使用されていたサポートロール５は存在せず、その代わりにガスワイピングノズル６の直後に電磁石を用いた非接触で金属帯の形状を矯正する形状矯正装置９が設けられている点、及びさらに溶融金属浴槽２内に囲み部材８を設けた点が特徴である。
【００５４】
溶融金属浴槽２内に設けた囲み部材８の構成と作用、及び形状矯正装置９の構成と作用について以下に説明する。先ず、囲み部材８について説明する。
【００５５】
図３の装置には、溶融金属浴３内に引き込まれた金属帯１を囲むように形成された囲み部材８が設けられている。囲み部材８によって、前記溶融金属浴３内が溶融金属の流動可能な状態で上部領域３Ａと下部領域３Ｂに分割されている。
【００５６】
囲み部材８の上端は溶融金属浴３の浴面より下にあり、囲み部材８の金属帯引き上げ側の囲み８ｂの上端は、シンクロール４の軸芯よりも上にある。囲み部材８の金属帯１下面に対向する側の囲みは、囲み部材８とシンクロール４の距離がほぼシンクロール４下方で最も近接するように構成されている。また、囲み部材８の金属帯１端部側（シンクロール４軸方向側）の囲み８ｃはほぼ鉛直な側壁で構成されている。
【００５７】
囲み部材８は高温の溶融金属浴環境での使用に耐え得るＳＵＳ材などで製作される。囲み部材８の下部に囲み部材８を支持する脚状の支持部材(図示なし)が取り付けられており、前記支持部材が溶融金属浴槽２底部に載置されることで、囲み部材８は溶融金属浴槽２内に設置される。囲み部材８は溶融金属浴槽２内への取り付け、溶融金属浴槽２外への取り外しが自在である。
【００５８】
囲み部材８を設けたことによる作用について、図４を参照して説明する。図４中の矢印は溶融金属浴３の流れ方向を示す。ハッチング付き矢印はドロスを含み、清浄化前の溶融金属浴３であることを示し、白抜き矢印はドロスが沈降除去され、清浄化された溶融金属浴３であることを示す。
【００５９】
上部領域３Ａでは、溶融金属浴３は、走行する金属帯１に随伴して流れ、囲み部材８の金属帯１引き上げ側の囲み８ｂの上方から下部領域３Ｂに流出する。上部領域３Ａのシンクロール４下方領域では、シンクロール４の回転による随伴流があるので、金属帯１が通板されていない領域でも溶融金属浴３の十分な流動が確保される。
【００６０】
上部領域３Ａでは、金属帯である鋼帯１から鉄（Ｆｅ）が溶出し、微細なＦｅ−Ｚｎ系ドロスが生成する。微細なドロスの一部は金属帯１に付着して溶融金属浴３から持ち出される。この微細なドロスは金属帯１に付着しても品質上の問題はない。溶融金属浴３から持ち出されなかった溶融金属浴３中の微細なドロスは、通板される金属帯１に随伴する流れによって、囲み部材８の金属帯１引き上げ側の囲み８ｂの上方から下部領域３Ｂに速やかに排出され、上部領域３Ａ内で沈降、堆積することがない。
【００６１】
下部領域３Ｂには、上部領域３Ａから微細なドロスを含む溶融金属浴３が流入する。下部領域３Ｂに流入した微細なドロスを含む溶融金属浴３は、溶融金属浴槽２の金属帯１引き上げ側の側壁２ａに沿って主に下方に向かう流れになり、さらに囲み部材８の下方と側方を経て溶融金属浴槽２の金属帯１引き込み部側（スナウト７側）に流れる。
【００６２】
下部領域３Ｂは、上部領域３Ａに比較して容量が大きく、また上部領域３Ａの金属帯１随伴流の影響が直接及ばないので、溶融金属浴３の流れは緩やかである。そのため、下部領域３Ｂに流入した溶融金属浴３が金属帯１引き込み部側（スナウト７側）まで流れる間に、溶融金属浴３に含まれるドロスは、溶融金属浴槽２底部に沈降する。溶融金属浴槽２底部に沈降、堆積したドロスは、集合合体して金属帯品質に影響を与える大きなドロス１６に成長する。下部領域３Ｂでは流れが緩やかなので、溶融金属浴槽２底部に堆積した大きなドロス１６は、金属帯１通板速度が変化しても巻き上げられにくく、あるいは仮に巻き上げられることがあっても巻き上げられたドロス１６は速やかに溶融金属浴槽２底部に沈降する。そのため、下部領域３Ｂの金属帯１引き込み側の領域では溶融金属浴３は清浄である。特に浴面上部側の上澄み浴は一層清浄であり、金属帯品質に影響を与える大きなドロス１６が浮遊していない。
【００６３】
この清浄化された溶融金属浴３の上澄み浴は、通板される金属帯１の随伴流によって、囲み部材８の金属帯１引き込み側の囲み８ａの上方から上部領域３Ａに流入する。金属帯１は、スナウト７から溶融金属浴３に引き込まれ、前記清浄化された溶融金属浴３を随伴しながら上部領域３Ａ内をシンクロール４によって方向転換され溶融金属浴３から引き上げられる。金属帯１が溶融金属浴３に引き込まれ、溶融金属浴３から引き上げられるまでの間に、金属帯１通板領域に品質影響のあるドロス１６がないので、溶融金属浴３から引き上げられた金属帯１表面に品質影響のあるドロス１６の付着が防止される。
【００６４】
囲み部材８は、シンクロール４、金属帯１との最近接間隔が５０ｍｍ以上４００ｍｍ以下とするように設置されることが好ましい。５０ｍｍ未満であると、熱変形による金属帯１との接触や囲み部材８を設置する際に位置決めが大変になり、また４００ｍｍ超になると、囲み部材８内で金属帯１の随伴流の影響が及ばなくなる領域が発生し、囲み部材８内で発生したドロスを囲み部材８外部の下部領域３Ｂに持ち出しにくくなってドロスが囲み部材８内部（上部領域３Ａ内）に堆積するようになるためである。
【００６５】
囲み部材８は、囲みの上端が浴面上になるように設けることができる。この場合、囲み部材８の金属帯１引き込み側の囲み８ａの浴面部分または浴面に近い浴中部分に、下部領域３Ｂの溶融金属浴３を上部領域３Ａに導入する開口部を設け、また囲み部材８の金属帯１引き上げ側の囲み８ｂの浴面部分または浴面に近い浴中部分に、上部領域３Ａの溶融金属浴３を下部領域３Ｂに流出する開口部を設ける。しかし、囲み部材８が浴面上にあると、囲み部材８内の浴面に発生するトップドロスを溶融金属浴槽２外に取り出す作業が煩雑になり、またトップドロスが囲み部材８に付着し、鋼帯１の随伴流によって上部領域３Ａの溶融金属浴３を下部領域３Ｂに流出し、下部領域３Ｂから清浄な溶融金属浴３を上部領域３Ａに導入するという本発明の作用が低下するおそれがあるので、囲み部材８の上端は浴面より下に設けることが好ましい。囲み部材８の上端が浴面より１００ｍｍ未満になると鋼帯１の随伴流によって浴面が攪拌されトップドロスの発生量を増加させるため、浴面より１００ｍｍ以下にすることがさらに好ましい。
【００６６】
また、上部領域３Ａ内を通板される金属帯１の随伴流が下部領域３Ｂ内に影響を及ぼすこと、また下部領域３Ｂの溶融金属浴槽２の底部に堆積しているドロスを巻き上げることを防止する観点から、囲み部材８の各囲みの上端（金属帯引き込み側８ａの上端、金属帯引き上げ側の囲み８ｂの上端および金属帯幅方向の囲み８ｃの上端）はシンクロール４の軸心よりも上にあることが好ましく、シンクロール４の最上部よりも上にあることがさらに好ましい。
【００６７】
囲み部材８の金属帯引き込み側の囲み８ａと金属帯１との距離は１０００ｍｍ以下であることが好ましく、金属帯引き上げ側の囲み８ｂと金属帯１との距離は８００ｍｍ以下であることが好ましい。
【００６８】
シンクロール４最上部と溶融亜鉛浴面との間隔は５０ｍｍ以上４００ｍｍ以下とすることが好ましい。５０ｍｍ未満であるとシンクロール４の回転により浴面が攪拌されトップドロスを多量に発生させ、また４００ｍｍ超になると、深い溶融金属浴槽２が必要となり、設備費等の増加を招くためである。
【００６９】
シンクロール４最下部と溶融金属浴槽２底部の間隔は４００ｍｍ以上である（但し、囲み部材８と金属帯１との最近接間隔が５０ｍｍ以上４００ｍｍ以下とする場合には、４００ｍｍに囲み部材８の厚さを加えた値を超えるものとする）ことが好ましい。４００ｍｍ超になると溶融金属浴槽２底部に十分なドロス沈殿部が確保できなくなり、および／またはシンクロール４や金属帯１に接触せずに囲み部材８を設置することが難しくなるためである。
以上説明したように、溶融金属浴槽２内の溶融金属浴３の主要な流れは、上部領域３Ａでは、金属帯１随伴流によって、金属帯１引き込み側から金属帯１引き上げ側への一方向の流になって、金属帯１引き上げ側の囲み８ｂから下部領域３Ｂに流出される。下部領域３Ｂでは、溶融金属浴３は、溶融金属浴槽２の鋼帯引き上げ側の側壁２ａに沿って下方に流れ、さらに囲み部材８の下方及び側方を経て金属帯１引き込み側に流れ、上部領域３Ａとは逆方向に向かう流れとなる。このように、上部領域３Ａと下部領域３Ｂ間を溶融金属浴３は循環するが、この溶融金属浴３循環の起動力は、実質的に通板される金属帯１の随伴流によるものであり、循環のためのポンプ等の設備を必要としないので、簡易且つ安価な設備にできるという利点がある。
【００７０】
本発明では、浴中サポートロール５を設置しないので、シンクロール４径は、サポートロール５が設置された従来装置（図１２）の場合よりも大きくすることができる。図５は、一般的に使用されているロール径であるφ７５０ｍｍのシンクロール４とシンクロール径をφ９５０ｍｍに大径化した場合について、ガスワイピングノズル６部で、幅１２００ｍｍの鋼帯１に発生するＣ反り量を調査した結果である。鋼帯１のＣ反り量の数値は、シンクロール４側に凸形状の場合は＋（プラス）、シンクロール４と反対側に凸形状の場合は−（マイナス）とした。
【００７１】
シンクロール４径を大きくすることによりシンクロー４に巻き付けられた鋼帯１に発生する曲げ応力を小さくすることができ、その結果、図５に示されるように溶融金属浴３から引き上げられるときの鋼帯１のＣ反りを小さくできる。これによって、形状矯正用の電磁石の負荷軽減が可能になり、従来反り矯正が困難であった厚物鋼帯についても溶融金属浴３引き上げ部の形状を平坦にできる。係る点からは、シンクロール４の直径は８５０ｍｍ以上とすることが有利である。
【００７２】
次に、形状矯正装置９について説明する。形状矯正装置９はガスワイピングノズル６の直後に設置されている。ここでガスワイピングノズル６の直後とは、ガスワイピングノズル６に近ければより良い制御が行えることを意味している。実ラインでガスワイピングノズル６の上方に、めっき皮膜の合金化処理を行う合金化炉、スパングルを調整するスパングル調整装置などが設けられ、また前記装置の前に金属帯１の振動を抑制するタッチロールが設けられる場合もある。この場合、形状矯正装置９は、前記装置までの間に設置すれば良い。
【００７３】
図６は、図３の装置に設置される電磁石を用いた非接触で金属帯の形状を矯正する形状矯正装置９の構成を示す図である。
【００７４】
本形状矯正装置９は、図中上方に移動する金属帯１の表面までの距離を測定する位置センサ１０、この位置センサ１０からの信号を受けて制御信号を出力する制御器１１、制御信号を増幅する増幅器１２及び増幅された制御信号によって金属帯に吸引力を及ぼして金属帯の形状を変化させる電磁石１３で構成されている。
【００７５】
そして、電磁石１３は金属帯１の幅方向に複数台数設けられ、さらに金属帯１の表裏に対になって配置されている。電磁石１３は金属帯１に対しては一方向の吸引力を及ぼすものであるため、金属帯１の表裏に配置することで金属帯１の吸引方向を選択して金属帯１の反りを矯正できるように構成されている。
【００７６】
通常、金属帯１の幅方向の反り形状は図１で示すように、断面がＣ形になることが多いため、電磁石１３は金属帯幅方向３ヶ所（両エッジ、中央）に配置すれば良い。また、各３ヶ所の位置センサ１０相互間、電磁石１３相互間での干渉はそれほど大きくないことが多いため、相互の干渉を補償せずに、３ヶ所それぞれ独立の制御系で構成しても良い。
【００７７】
本装置を用いて、金属帯１の表面までの距離を測定する位置センサ１０からの信号に基いて、制御器１１で金属帯１の表裏に配置されている電磁石１３の吸引力を制御し、金属帯１の反りを矯正する。これによって溶融金属浴３引き上げ部の金属帯１の反りを平坦にできる。
【００７８】
次に、前記装置を用いて、溶融亜鉛めっき鋼帯を製造する方法について説明する。鋼帯１はスナウト７を通って溶融金属浴３内の上部領域３Ａに引き込まれ、方向転換用ロールであるシンクロール４によって通板方向が変換され溶融金属浴３から引き上げられる。次にガスワイピングノズル６でめっき付着量が調整される。ガスワイピングノズル６部の鋼帯１形状は形状矯正装置９で矯正されて平坦にされる。さらに必要に応じて、図示されていない合金化炉でめっき層の合金化処理され、又はスパングル調整装置でスパングル調整され、あるいはそのまま冷却されて所要の溶融亜鉛めっき鋼帯が製造される。
【００７９】
前記装置では、表面に品質影響のあるドロスの鋼帯１表面への付着を抑制する作用が優れるので、鋼帯１通板速度を低下しなくてもすなわち生産効率を低下しなくても、ドロス付着のない高品質の溶融亜鉛めっき鋼帯を製造できる。
【００８０】
また、ガスワイピングノズル６部で鋼帯１の幅方向反りが矯正されているので、鋼帯１幅方向の付着量分布を均一にでき、さらにガスワイピングノズル６と鋼帯１の間隔を狭め、ガス圧力を低圧にして付着量調整することで、スプラッシュの発生を防止できる。
【００８１】
またサポートロールが設置されていないので、サポートロールに起因する品質欠陥の発生がなく、またサポートロール交換のための設備停止も不要である。
【００８２】
なお、下部領域３Ｂの底部すなわち溶融金属浴槽２底部にドロス１６が堆積する。囲み部材８を溶融金属浴槽２外に取り外し、堆積したドロス１６を従来から知られている手段によって溶融金属浴槽２の外部に取り出すことができる。
【００８３】
図７〜図１０は本発明の第１の実施の形態の溶融めっき金属帯製造装置に設置される囲み部材８の他の実施の形態を示す図である。図７〜図１０中、浴中の矢印は溶融金属の流れ方向を示す。
【００８４】
図７では、囲み部材８の金属帯１引き上げ側の囲み８ｂは、金属帯１がシンクロール４から離れて通板される部分ではパスラインと略平行に構成されている。上部領域３Ａでは、溶融金属浴３が下部領域３Ｂに排出されるまで、金属帯１走行の随伴流の流速が高速に維持されるので、上部領域３Ａの溶融金属浴３は下部領域３Ｂにより効率よく流出される。囲み部材８の金属帯１引き上げ側の囲み８ｂ上端はシンクロール４最上部より高く、浴面から１００ｍｍ以上の深さであることが好ましい。囲み部材８の金属帯１引き上げ部側の囲み８ｂ上端がシンクロール４最上部より高くなると溶融金属浴槽２底部から巻き上げたドロスが上部領域３Ａに流入しやすくなり、また浴面より１００ｍｍ未満になると随伴流が浴面を攪拌してトップドロスの発生量を増加させるためである。
【００８５】
図８では、図７に示した囲み部材８において、その金属帯１引き上げ側の囲み８ｂ上端外側に、下部領域３Ｂで沈降堆積しているドロスの巻き上げを防止するための巻き上げ防止板１４が付設されている。巻き上げ防止板１４を付設することによって、上部領域３Ａから流出する溶融金属浴３の流れによって、下部領域３Ｂで沈降堆積しているドロスが上部領域３Ａの金属帯１引き上げ側の領域に巻き上げられることが防止される。浴面の乱れを抑制する観点から、巻き上げ防止板１４は水平面に対して斜め前方に傾斜していることが好ましい。巻き上げ防止板１４は、囲み部材８の金属帯１引き込み側の囲み８ａ上端および金属帯１端部側の囲み８ｃ上端にも設置しても良い。
【００８６】
図９では、図７に示した囲み部材８において、金属帯１引き上げ側の囲み８ｂ上端外側に図８に付設されたのと同様の巻き上げ防止板１４が設置され、さらに前記巻き上げ防止板１４と浴面との間に随伴流の流れ方向を変更し、かつ随伴流が浴面を乱すことを防止するために、整流板１５が浴面に略平行に設置されている。整流板１５の金属帯１側端部は、随伴流の方向転換を行い易くするために、上部領域３Ａの随伴流の流路よりも金属帯１に近くなるように設置することが好ましい。但し、金属帯１との接触を避けるために金属帯１から３０ｍｍ以上離すことが望ましい。
【００８７】
図１０では、囲み部材８は、金属帯１随伴流を金属帯１から離れさせかつ随伴流が浴面を乱さないようにする整流構造物１６が付設されている。整流構造物１６は、従来技術の装置でサポートロールが配置されていた場所に設置されている。
【００８８】
囲み部材８の金属帯１引き上げ側の囲み８ｂは、外側上方に傾斜して構成され、その上端外側に、図８の巻き上げ防止板１４と同様の作用をする巻き上げ防止板１４が付設されている。
【００８９】
整流構造物１６は、金属帯１引き上げ側の囲み８ｂとパスラインとの間に付設されている。該整流構造物１６は、パスラインに対向する側１６ａがパスラインと略平行で、金属帯１引き上げ側の囲み８ｂに対向する側１６ｂは金属帯１引き上げ側の囲み８ｂに略平行に構成され、さらに該整流構造物１６の上部１６ｃは略水平に構成されるとともに、その金属帯１引き上げ側の囲み８ｂに対向する側に略水平な整流板１６ｄが付設されている
図１０の装置では、囲み部材８が上記のように構成されているので、該囲み８ｂと整流構造物１６に挟まれる領域で金属帯１随伴流の流速を低下させずに金属帯１から離れさせかつ随伴流が浴面を乱さないようにすることができる。金属帯１との接触防止の観点から、この整流構造物１６と金属帯１との間隔は３０ｍｍ以上とすることが望ましい。
【００９０】
図１１は本発明の第２の実施の形態の溶融めっき金属帯製造装置の構成を示す図である。本構成では、形状矯正装置９をガスワイピングノズル６の直後に配置する図３に示す構成に代えて、形状矯正装置９をガスワイピングノズル６の直前に配置したことが特徴である。ここで直前とは、ガスワイピングノズル６に近ければより良い制御が行えることを意味しているが、実ラインでは溶融金属浴３からガスワイピングノズル６までの間に設置すれば良い。本装置でも前記図３に示した装置と同様の効果を奏することができる。
【００９１】
【実施例】
（実施例１）
本発明例については、図３に示した溶融めっき金属帯製造装置を用いて、幅１２００ｍｍ、厚み１．０ｍｍの鋼帯１を速度９０ｍｐｍ、張力２ｋｇ／ｍｍ²で連続的に通板させ、ガスワイピングノズル６により鋼帯片面当りの付着量を４５ｇ／ｍ²になるようにガス圧力を調整して溶融亜鉛めっき鋼帯を製造した。シンクロール４は直径８００ｍｍで、余剰の亜鉛を払拭するために設けたガスワイピングノズル６直後の鋼帯１幅方向３箇所に設けた磁力（静磁場）によりＣ反り矯正を行う電磁石１３を鋼帯パスラインから２０ｍｍ離れた位置に設置した。この電磁石１３を用いた形状矯正装置９を用いて、ガスワイピングノズル６部での鋼帯１Ｃ反り量がなくなるように位置センサ１０で計測した鋼帯１のＣ反り量に応じて各電磁石１３の電流調整を行った。溶融金属浴３内に設置した囲み部材８の鋼帯面に対面する側は、シンクロール４に沿うような形状とし、鋼帯１との間隔を最小で１５０ｍｍとした。またシンクロール４最上部と浴面との距離は約６００ｍｍとした。
【００９２】
前記で製造した溶融亜鉛めっき鋼帯について、３００ｍｍ角のサンプルで鋼帯表面を観察したところ、ドロスは確認できなかった。また、鋼帯１幅方向の付着量の偏差は約±５ｇ／ｍ²であった。
【００９３】
一方、比較のために、図１２に示したサポートロール５を有する装置で、前記と同一サイズの鋼帯１をライン速度９０ｍｐｍ、鋼帯片面当りの付着量を４５ｇ／ｍ²に調整して溶融亜鉛めっき鋼帯を製造し、前記と同様の調査をしたところ、鋼帯１幅方向の付着量の偏差は約±１０ｇ／ｍ²であり、３００ｍｍ角のサンプルのドロス個数は約２０個であった（従来例）。また、図３に示した装置で、浴中の囲み部材８を取り除き、本発明例と同様の条件で溶融亜鉛めっき鋼帯を製造した場合には、３００ｍｍ角のサンプルのドロス個数は約１０個であった。鋼帯１の幅方向の付着量の偏差は約±５ｇ／ｍ²であった（比較例）。
【００９４】
前記のように、本発明例では、従来例に比べて、鋼帯１に付着するドロスを抑制し、かつ鋼帯１幅方向の付着量がより均一化されている。比較例は、囲み部材８を取り除いたのでドロスの発生が抑制されていない。
【００９５】
（実施例２）
本発明例については、図３に示した溶融金属めっき装置を用いて、幅１２００ｍｍ、厚み１．０ｍｍの鋼帯１を速度９０ｍｐｍ、張力２ｋｇ／ｍｍ²で連続的に通板させ、ガスワイピングノズル６により鋼帯片面当りの付着量を４５ｇ／ｍ²になるようにガス圧力を調整して溶融亜鉛めっき鋼帯を製造した。シンクロール４は直径９５０ｍｍで、余剰の亜鉛を払拭するために設けたガスワイピングノズル６直後の鋼帯１幅方向３箇所に設けた磁力（静磁場）により鋼帯１Ｃ反り矯正を行う電磁石１３をパスラインから２０ｍｍ離れた位置に設置した。この電磁石１３を用いた形状矯正装置９を用いて、ガスワイピングノズル部でのＣ反り量がなくなるように位置センサ１０で計測した鋼帯１のＣ反り量に応じて各電磁石１３の電流調整を行った。溶融金属３内に設置した囲み８の鋼帯面に対面する側は、シンクロール４に沿うような形状とし、鋼帯１との間隔を最小で１００ｍｍとした。またシンクロール４最上部と浴面との距離は約２００ｍｍとした。
【００９６】
前記で製造した溶融亜鉛めっき鋼帯について、３００ｍｍ角のサンプルで鋼帯表面を観察したところ、ドロスは確認できなかった。また、鋼帯１幅方向の付着量の偏差は約±５ｇ／ｍ²であった。
【００９７】
一方、比較のために、図１２に示したサポートロール５を有する装置で、前記と同一サイズの鋼帯１をライン速度９０ｍｐｍ、鋼帯片面当りの付着量を４５ｇ／ｍ²に調整して溶融亜鉛めっき鋼帯を製造し、前記と同様の調査をしたところ、鋼帯１幅方向の付着量の偏差は約±１０ｇ／ｍ²であり、３００ｍｍ角のサンプルのドロス個数は約１７個であった（従来例）。また、図３に示した装置で、浴中の囲み部材８を取り除き、本発明例と同様の条件で溶融亜鉛めっき鋼帯を製造した場合には、３００ｍｍ角のサンプルのドロス個数は約１４個であった。鋼帯１幅方向の付着量の偏差は約±４ｇ／ｍ²であった（比較例）。
【００９８】
【発明の効果】
以上説明したように、本発明によれば、浴中サポートロールを用いずに溶融めっき金属帯を製造できるので、浴中サポートロールに起因する欠陥のない溶融めっき金属帯を製造することができる。また、浴中サポートロールのメンテナンスが不要となるため、溶融めっき金属帯の製造効率を上げることができる。また、浴中サポートロールのメンテナンスが不要となるため、メンテナンス費用を削減することができる。
【００９９】
また、本発明によれば、厚物金属帯であってもガスワイピングノズル部における金属帯の反りを平坦にして、金属帯幅方向に均一な付着量の溶融めっき金属帯を製造することができる。
【０１００】
また、本発明によれば、ドロス付着による品質欠陥の発生を抑制する作用が優れるので、金属帯通板速度を低下しないですなわち生産効率を低下しないでドロス欠陥のない高品質の溶融めっき金属帯を製造できる。
【図面の簡単な説明】
【図１】金属帯幅方向反り発生機構を説明する図。
【図２】サポートロールの反り矯正機能を説明する図。
【図３】本発明の第１の実施の形態の溶融めっき金属帯製造装置の構成を示す図。
【図４】図３の装置に設けた囲み部材の作用を説明する図。
【図５】シンクロール径と鋼帯Ｃ反り量の関係を示す図。
【図６】電磁石を用いた形状矯正装置の構成を示す図。
【図７】本発明の第１の実施の形態の溶融めっき金属帯製造装置に設置される囲み部材の別の実施の形態を示す図。
【図８】本発明の第１の実施の形態の溶融めっき金属帯製造装置に設置される囲み部材の別の実施の形態を示す図。
【図９】本発明の第１の実施の形態の溶融めっき金属帯製造装置に設置される囲み部材の別の実施の形態を示す図。
【図１０】本発明の第１の実施の形態の溶融めっき金属帯製造装置に設置される囲み部材の別の実施の形態を示す図。
【図１１】本発明の第２の実施の形態の溶融めっき金属帯製造装置の構成を示す図。
【図１２】従来技術の溶融めっき金属帯製造装置の構成を示す図。
【符号の説明】
１金属帯（鋼帯）
２溶融金属浴槽
３溶融金属浴
４方向転換ロール（シンクロール）
５サポートロール
６ワイパ（ガスワイピングノズル）
７スナウト
８囲み部材
８ａ囲み部材の金属帯引き込み側の囲み
８ｂ囲み部材の金属帯引き出し側の囲み
８ｃ囲み部材の金属帯端部側（シンクロール軸方向側）の囲み
９形状矯正装置
１０位置センサ
１１制御器
１２増幅器
１３電磁石
１４巻き上げ防止板
１５整流板
１６整流構造物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method and a manufacturing apparatus for a hot-dip metal strip.In placeRelated.
[0002]
[Prior art]
There is known a manufacturing method of a hot-dip metal strip which is manufactured by continuously immersing a metal strip such as a steel strip in a molten metal such as zinc or aluminum and plating the surface of the metal strip.
[0003]
FIG. 12 shows the configuration of a conventional apparatus for continuously producing a hot-dip metal strip. In FIG. 12, 1 is a metal strip, 2 is a molten metal bath, 3 is a molten metal bath, 4 is a sink roll that is a direction change roll, 5 is a support roll, 6 is a gas wiping nozzle that is a wiper, and 7 is a snout.
[0004]
A case where a hot-dip galvanized steel strip is produced using this apparatus will be described as an example. In this case, the molten metal is zinc. The steel strip 1 coming out of the snout 7 is continuously drawn into the molten metal bath 3 in the molten metal bath 2, wound around the sink roll 4, the plate passing direction is changed, and after passing through the support roll 5, the molten metal bath 3 is pulled up, and high pressure gas is blown from a gas wiping nozzle 6 installed on the molten metal bath 3 to wipe away excess zinc adhering to the surface of the steel strip 1 to adjust to a predetermined plating adhesion amount. Manufacture plated steel strip.
[0005]
The support roll 5 is installed to correct the warp in the width direction (C warpage) of the steel strip 1 at the gas wiping nozzle 6 and to reduce variations in the amount of adhesion in the width direction of the steel strip 1. One support roll 5 is installed on each side of the steel strip 1 and the height of each support roll 5a, 5b is shifted. And the support roll 5a arrange | positioned upwards is arrange | positioned so that a pass line may be touched, the support roll 5b installed below may be pushed into the steel strip 1 side, and an appropriate amount of deformation | transformation may be given to the steel strip 1, C Correct warpage.
[0006]
However, when the C warp of the steel strip 1 is corrected by the support rolls 5a and 5b, there are the following problems. That is, since the support rolls 5a and 5b are driven via a spindle (not shown) by a motor (not shown) installed at a position higher than the molten metal bath surface on the side of the molten metal bath 2, the rotation of the motor is constant. Even so, the support rolls 5a and 5b do not rotate at a constant speed. As a result, the rotation speeds of the support rolls 5a and 5b not only coincide with the steel strip speed but also cannot rotate at a constant speed, so that the chatter mark-like adhesion amount irregularities and the dross described later adhere to the roll surface. Doing so may cause rubbing and may cause quality problems.
[0007]
In order to solve the above-mentioned problems caused by rotationally driving the support rolls 5a and 5b, it is conceivable to idle (non-drive) the support rolls 5a and 5b. In this case, in order to ensure the rotation of the support rolls 5a and 5b, it is necessary to increase the pushing amount of the support roll 5b. However, by increasing the pushing amount of the support roll 5b, it becomes impossible to properly correct the C warpage of the steel strip 1 at the place where it comes out of the bath surface (gas wiping nozzle 6 part). There is a problem that the variation in the amount of the adhesion increases.
[0008]
When a hot dip galvanized steel strip is manufactured using the apparatus shown in FIG. 12, dross (so-called bottom dross) 16 that is an intermetallic compound of iron (Fe) eluted from the steel strip 1 and a plating component is generated. The dross 16 accumulates at the bottom of the molten metal bath 2, and the accumulated dross 16 is rolled up and floats in the molten metal bath 3. When the dross 16 adheres to the steel strip 1, there is a problem that the surface quality of the steel strip 1 is deteriorated and a defect is generated during pressing. Although the dross adhesion to the steel strip 1 is reduced by reducing the steel strip passage speed, there is a problem that the production efficiency is lowered.
[0009]
[Problems to be solved by the invention]
In view of the above circumstances, the object of the present invention is to prevent chatter mark-like adhesion amount unevenness and scuffing caused by the support roll in the bath, and to prevent warping in the width direction of the metal strip in the gas wiping portion. Manufacturing method and apparatus for hot-dip metal strip that can reduce the variation in the amount of adhesion in the width direction of the metal strip and can prevent the occurrence of dross defects on the metal strip without lowering the production efficiency.PlaceIt is to provide.
[0010]
[Means for Solving the Problems]
Means of the present invention for solving the above-mentioned problems are as follows.
[0011]
(1) A drawing step of drawing a metal strip into a molten metal bath that is a plating metal and attaching the molten metal to the metal strip;
By the surrounding member formed so as to surround the metal strip drawn into the molten metal bath, the molten metal bath is divided into an upper region and a lower region in a state in which the molten metal can flow, Is a direction of turning by the direction change roll in the upper region, and after the direction change, the pulling step to be pulled out of the molten metal bath without contacting the roll in the molten metal bath,
An adjusting step of adjusting the amount of adhesion of the molten metal by a wiper that wipes off the excess molten metal adhering to the metal band;
A shape correction step of correcting the shape of the metal strip immediately before or after the wiper by a magnetic force in a non-contact manner;
HaveAnd the surrounding member of the said raising process is either of the following (I)-(D)A method for producing a hot dipped metal strip characterized by the above.
(B) The enclosure on the metal band pulling side is configured to be substantially parallel to the pass line at the portion where the metal band is separated from the sink roll, and the upper end of the metal band pulling side is higher than the uppermost part of the sink roll and The surrounding member comprised so that it might become 100 mm or more from a bath surface.
(B) A surrounding member in which a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is attached to the outside of the upper end of the encircling side of the metal band pulling side.
(C) A hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is provided outside the upper end of the enclosure on the metal band pulling side, and the hoisting prevention plate and the bath are further provided. An enclosing member in which a flow straightening plate for changing the flow direction of the accompanying flow with respect to the surface and preventing the accompanying flow from disturbing the bath surface is provided substantially parallel to the bath surface.
(D) The metal band lifting side enclosure is configured to be inclined upward and outward, and the metal band accompanying flow is separated from the metal band between the metal band lifting side enclosure and the pass line, and the accompanying flow is A rectifying structure is provided to prevent the bath surface from being disturbed, and the rectifying structure is substantially parallel to the pass line on the side facing the pass line, and the side facing the encircling side of the metal band pulling side is the metal band. An enclosing member configured to be substantially parallel to the enclosure on the pulling side.
(2) In the above (1), the enclosure member (b) or (c) is configured so that the enclosure on the metal band lifting side is substantially parallel to the pass line at the portion where the metal band is separated from the sink roll. The method for producing a hot dipped metal strip according to (1) above, wherein the upper end of the metal strip pulling side is higher than the uppermost portion of the sink roll and is 100 mm or more from the bath surface. .
(3) In the above (1), the encircling member in (d) is provided with a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath on the outer side of the encircling upper end on the metal band raising side. The upper part of the rectifying structure is configured to be substantially horizontal, and a substantially horizontal rectifying plate is attached to the side facing the enclosure on the metal band lifting side. The manufacturing method of the hot dipped metal strip of description.
[0012]
(4) The molten metal bath containing dross generated in the upper region flows out from the side of pulling up the metal band of the surrounding member out of the molten metal bath to the lower region, and the dross contained in the molten metal bath in the lower region The molten metal bath is cleaned by settling and removal, and the cleaned molten metal bath is introduced into the upper region from the side of the metal band of the surrounding member drawn into the molten metal bath.Any of (1) to (3)The manufacturing method of the hot dipped metal strip as described in any one of Claims 1-3.
[0013]
(5The enclosing member is provided below the molten metal bath surface.Any of (1) to (4)The manufacturing method of the hot dipped metal strip as described in any one of Claims 1-3.
[0014]
(6) The closest distance between the direction change roll and the surrounding member is 50 mm or more and 400 mm or less.5) The method for producing a hot dipped metal strip according to any one of the above.
[0015]
(7) The interval between the uppermost part of the direction change roll and the molten metal bath surface is not less than 50 mm and not more than 400 mm.6) The method for producing a hot dipped metal strip according to any one of the above.
[0016]
(8) The outer diameter of the direction change roll is φ850 mm or more.7) The method for producing a hot dipped metal strip according to any one of the above.
[0017]
(9) The distance between the lower surface of the direction change roll and the bottom of the molten metal bath is 400 mm or more (the above (6In the case of (), the value exceeds the value obtained by adding the thickness of the enclosing member to 400 mm).8) The method for producing a hot-dip metal strip according to any one of the above.
[0018]
(10) In an apparatus for producing a hot dipped metal strip by drawing the metal strip into a bath of hot metal, which is a plated metal,
A roll that holds the molten metal and adheres the molten metal to the metal band, and has a direction changing roll that changes the direction of the metal band in the molten metal bath, and is in contact with the metal band after the direction change. A molten metal bathtub without
The molten metal bath is formed so as to surround a metal strip drawn into the molten metal bath and to divide the molten metal bath into an upper region and a lower region in a state in which the molten metal can flow, A surrounding member formed such that the metal strip redirected by the redirecting roll in the region is pulled out of the molten metal bath;
A wiper that adjusts the amount of adhesion by wiping away excess molten metal adhering to the metal strip;
A shape correcting device for correcting the shape of the metal strip immediately before or after the wiper by magnetic force in a non-contact manner;
WithAnd the surrounding member is one of the following (A) to (D)An apparatus for producing a hot dipped metal strip characterized by the above.
(B) The enclosure on the metal band pulling side is configured to be substantially parallel to the pass line at the portion where the metal band is separated from the sink roll, and the upper end of the metal band pulling side is higher than the uppermost part of the sink roll and The surrounding member comprised so that it might become 100 mm or more from a bath surface.
(B) A surrounding member in which a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is attached to the outside of the upper end of the encircling side of the metal band pulling side.
(C) A hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is provided outside the upper end of the enclosure on the metal band pulling side, and the hoisting prevention plate and the bath are further provided. An enclosing member in which a flow straightening plate for changing the flow direction of the accompanying flow with respect to the surface and preventing the accompanying flow from disturbing the bath surface is provided substantially parallel to the bath surface.
(D) The metal band lifting side enclosure is configured to be inclined upward and outward, and the metal band accompanying flow is separated from the metal band between the metal band lifting side enclosure and the pass line, and the accompanying flow is A rectifying structure is provided to prevent the bath surface from being disturbed, and the rectifying structure is substantially parallel to the pass line on the side facing the pass line, and the side facing the encircling side of the metal band pulling side is the metal band. An enclosing member configured to be substantially parallel to the enclosure on the pulling side.
(11) In the above (10), the enclosure member (b) or (c) is configured so that the enclosure on the metal band lifting side is substantially parallel to the pass line in the portion where the metal band is separated from the sink roll. The apparatus for producing a hot dipped metal strip according to (10), wherein the upper end of the enclosure on the metal strip pulling side is configured to be higher than the uppermost portion of the sink roll and 100 mm or more from the bath surface. .
(12) In (10), the encircling member in (d) is provided with a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath on the outer side of the encircling upper end of the metal strip pulling side. (10) characterized in that the upper part of the rectifying structure is substantially horizontal, and a substantially horizontal rectifying plate is attached to the side facing the enclosure on the metal band lifting side. The manufacturing apparatus of the hot dipped metal strip of description.
[0019]
(13) The enclosing member has a molten metal bath containing dross generated in the upper region flowing out from the encircling portion side on the pulling side of the metal strip out of the molten metal bath to the lower region, and the melting of the metal strip The molten metal bath, in which dross is settled and removed in the lower region, is introduced into the upper region from the enclosing portion side on the drawing side into the metal bath.Any one of (10) to (12)The manufacturing apparatus of the hot dipped metal strip described in 1.
[0020]
(14The enclosing member is provided below the molten metal bath surface.Any one of (10) to (13)The manufacturing apparatus of the hot dipped metal strip described in 1.
[0021]
(15) The closest distance between the direction change roll and the surrounding member is 50 mm or more and 400 mm or less,10) ~ (14) The apparatus for producing a hot dipped metal strip according to any one of the above.
[0022]
(16) The distance between the uppermost part of the direction change roll and the molten metal bath surface is 50 mm or more and 400 mm or less,10) ~ (15) The apparatus for producing a hot dipped metal strip according to any one of the above.
[0023]
(17) The outer diameter of the direction change roll is φ850 mm or more10) ~ (16) The apparatus for producing a hot dipped metal strip according to any one of the above.
[0024]
(18) The distance between the lower surface of the direction change roll and the bottom of the molten metal bath is 400 mm or more (the above (15In the case of ()) exceeding the value obtained by adding the thickness of the enclosing member to 400 mm).10) ~ (17) The apparatus for producing a hot dipped metal strip according to any one of the above.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail together with the background to the present invention.
The present inventors first focused on the support roll 5 in the bath in order to develop a new method for producing a hot-dip plated metal strip that solves the problems of the present invention. The main function of the support roll 5 is a metal band width direction warpage correction function.
[0032]
FIG. 1 is a diagram for explaining a metal band 1 width direction warpage generating mechanism. It is considered that the warp in the metal band width direction is mainly caused by bending and unbending of the metal band 1 in the sink roll 4. At the position A where the sink roll 4 is wound and in contact, plane strain deformation occurs, and the stress generated in the metal band 1 is on the side in contact with the sink roll 4 in both the metal band passing plate direction and the metal band width direction. Compressive stress, tensile stress on the opposite side, and stress distribution that is the basis of warping in the metal band width direction. Near the sink roll 4 and at a position B having a relatively large radius of curvature, a plane strain state is maintained and plastic deformation is performed at the position A. Therefore, a stress distribution opposite to the position A, that is, the sink roll 4 is obtained. The tensile stress is on the side in contact with the surface, and the compressive stress is on the opposite side. At the position C where the radius of curvature is almost 0, there is no restriction on in-plane deformation, and it is basically considered that the deformation easily received at the position A exists, that is, a convex state in the metal band width direction. .
[0033]
When the warp occurs in the metal strip 1 in this way, the gap between the metal strip 1 and the gas wiping nozzle 6 is not constant in the width direction in the gas wiping nozzle 6 portion. Will occur.
[0034]
Further, when the metal band 1 is warped, narrowing the interval between the metal band 1 and the gas wiping nozzle 6 is restricted in order to avoid contact between the metal band 1 and the gas wiping nozzle 6. As a result, the gas pressure of the gas wiping nozzle 6 must be increased in order to ensure a desired molten metal wiping capability, and this is sometimes caused by adhesion of molten metal that has violently scattered during gas wiping to the metal strip 1. It is known to cause defects called splash.
[0035]
Therefore, the warp generated in the sink roll 4 is corrected using the support roll 5 in the bath.
[0036]
FIG. 2 is a diagram for explaining the warp correction function of the support roll 5 in the apparatus shown in FIG. The metal strip 1 is turned in the vertical direction by the sink roll 4 and passed through. The support roll 5a is provided at a position in contact with the metal band 1 on the pass line, and the support roll 5b disposed below the support roll 5a by a predetermined distance holds the metal band 1 by a predetermined amount L with respect to the pass line. It is arranged at the push-in position.
[0037]
As described above, the metal strip 1 is warped due to bending and unbending by the sink roll 4, but by adjusting the pushing amount L appropriately using the support roll 5b, the metal strip 1 is reversed in the reverse direction. To correct the warp.
[0038]
Thus, the support roll 5 in the bath is a facility that has been used for many decades mainly to correct the warp in the width direction of the metal strip 1, and as described above, the chatter mark is attached to the metal strip 1. In addition to the problem of unevenness in the amount of sticking and rubbing, there is also a problem that the equipment needs to be stopped for periodic care and replacement of the support roll 5 and the operation efficiency is lowered. Regardless, it is considered that it is an indispensable facility for the hot dip metal strip production line from the results.
[0039]
Since these problems do not occur unless the support roll 5 is present in the bath, the present inventors have examined whether or not the support roll 5 can be removed from the hot dip metal strip manufacturing process.
[0040]
First, it was verified whether or not the metal strip quality was adversely affected by removing the support roll 5 in the bath. This is because at the manufacturing site, the support roll 5 has a foreign matter removing function that makes it difficult for foreign matters such as dross in the molten metal bath 3 to adhere to the metal strip 1 in addition to the above-described function. This is because there is a common theory that the occurrence of defects in the metal strip 1 is increased by removing the metal strip 1.
[0041]
This verification was performed by manufacturing an experimental apparatus that simulates the molten metal bath 3 and observing the flow behavior therein. The experimental apparatus uses water instead of the molten metal, and a roll simulating the sink roll 4 and the support roll 5 is disposed therein, and an endless belt simulating the metal strip 1 is arranged, and the actual melting is performed. The roll diameter and roll rotation speed were set so that the number of lay nozzles and fluid numbers around the roll in the metal bath were equal, so that the behavior in the molten metal bath could be simulated hydrodynamically. An experiment was conducted by adding aluminum powder as a tracer for observing the flow.
[0042]
As a result, the roll imitating the support roll 5 was not observed to peel off the foreign matter (aluminum powder) adhering to the belt, and the roll imitating the support roll 5 only pressed the foreign matter. From this result, it was determined that the support roll 5 in the bath does not have a foreign matter removing function as is commonly said, and even if the support roll 5 is removed, the occurrence of defects does not increase. . Moreover, when the galvanized steel strip was manufactured without using the support roll 5 using the hot dip metal strip manufacturing equipment shown in FIG. 12 in the actual line, it was confirmed that this did not increase the dross defects of the galvanized steel strip. It was done.
[0043]
Therefore, in order to remove the support roll 5, it is only necessary to replace the warp correction function in the width direction of the metal strip 1.
[0044]
In the case of a hot-dip metal strip, it is desirable that the means for correcting the warp is a non-contact type, and it is preferable to correct the shape of the metal strip using a magnetic force such as an electromagnet from the viewpoint of controllability. . By removing the support roll 5 and using a magnetic force such as an electromagnet instead to correct the shape of the metal band 1 (C warp correction), all of the above-mentioned problems caused by using the support roll 5 can be solved.
[0045]
In addition, the present inventors investigated the flow of molten zinc in the molten metal bath 2 and the generation mechanism of dross and the behavior of the dross in the molten metal bath 2 in normal galvanizing operation. confirmed.
[0046]
The dross (so-called bottom dross) 16 that adheres to the steel strip 1 and causes a quality defect is an intermetallic compound of iron (Fe) eluted from the steel strip 1 and the plating component in the molten metal bath 3. Since this dross is generated by a reaction between the plating component and iron eluted from the steel strip 1, it is fine at the beginning. Even if the fine dross adheres to the steel strip 1, there is no problem in quality.
[0047]
The fine dross contains an iron component and has a higher density than that of the molten metal bath 3, and thus settles in the molten metal bath 3. In continuous operation, the dross settles and accumulates at the bottom of the molten metal bath 2. The dross deposited at the bottom of the molten metal bath 2 is easily lifted by being rolled up by the accompanying flow of the steel strip 1 to be passed. In the process of deposition or in the process of repeated ascent and sink, fine dross aggregates into large dross due to changes in bath temperature and molten metal bath components.
[0048]
The large dross 16 is wound up by the accompanying flow of the steel strip 1 through which it passes, floats in the bath, and adheres to the surface of the steel strip 1. The large dross 16 attached to the surface of the steel strip 1 deteriorates the surface quality of the steel strip 1. If the steel strip passage speed is high, the accompanying flow becomes large, the dross 16 is likely to rise, and the occurrence of dross defects in the steel strip 1 increases.
[0049]
In order to prevent the occurrence of dross defects in the steel strip 1, it is necessary to prevent the dross 16 deposited on the bottom of the molten metal bath 2 from being rolled up. It is necessary to prevent a large influence on the bottom. Moreover, even if the dross 16 is wound up, it is necessary to prevent the rolled up dross 16 from moving to the region through which the steel strip 1 is passed.
[0050]
From such a viewpoint, as a result of various studies on the structure of the molten metal bath 2 and the flow of the molten metal bath 3, the enclosure formed so as to surround the steel strip 1 drawn into the molten metal bath 3 in the molten metal bath 2. A member is provided, and the molten metal bath 3 is divided into an upper region and a lower region in a state where the molten metal can flow, the steel strip 1 is plated in the upper region, and dross generated in the upper region is formed in the lower region. The upper region and the lower region are separated so that dross is settled and removed from the molten metal bath 3 to be cleaned, and the molten metal bath 3 cleaned in the lower region is introduced into the upper region. And found that the occurrence of dross defects in the steel strip 1 can be reduced.
[0051]
The present invention has been made based on the above findings.
[0052]
Hereinafter, embodiments of the present invention will be further described. In each embodiment described below, a steel strip is taken into consideration as one specific example of the metal strip. The hot dip galvanized steel strip is a galvanized steel strip, and the hot dip metal is zinc.
[0053]
FIG. 3 is a diagram showing a configuration of the hot-dip metal strip manufacturing apparatus according to the first embodiment of the present invention. In this apparatus, the support roll 5 used in the bath in the conventional apparatus shown in FIG. 12 does not exist. Instead, the shape of the metal band is formed in a non-contact manner using an electromagnet immediately after the gas wiping nozzle 6. This is characterized in that a shape correcting device 9 for correcting the above is provided and a surrounding member 8 is provided in the molten metal bath 2.
[0054]
The configuration and operation of the surrounding member 8 provided in the molten metal bathtub 2 and the configuration and operation of the shape correction device 9 will be described below. First, the enclosing member 8 will be described.
[0055]
The apparatus shown in FIG. 3 is provided with a surrounding member 8 formed so as to surround the metal strip 1 drawn into the molten metal bath 3. By the surrounding member 8, the inside of the molten metal bath 3 is divided into an upper region 3A and a lower region 3B in a state where the molten metal can flow.
[0056]
The upper end of the enclosing member 8 is below the bath surface of the molten metal bath 3, and the upper end of the enclosing member 8 b on the metal band lifting side of the enclosing member 8 is above the axis of the sink roll 4. The enclosure on the side facing the lower surface of the metal band 1 of the enclosure member 8 is configured such that the distance between the enclosure member 8 and the sink roll 4 is closest to the lower part of the sink roll 4. In addition, the enclosure 8c on the metal band 1 end side (the sink roll 4 axial direction side) of the enclosure member 8 is configured by a substantially vertical side wall.
[0057]
The surrounding member 8 is made of a SUS material that can withstand use in a high-temperature molten metal bath environment. A leg-shaped support member (not shown) for supporting the enclosure member 8 is attached to the lower part of the enclosure member 8, and the support member is placed on the bottom of the molten metal bath 2 so that the enclosure member 8 is made of molten metal. It is installed in the bathtub 2. The surrounding member 8 can be attached to the molten metal bath 2 and removed from the molten metal bath 2.
[0058]
The effect | action by having provided the surrounding member 8 is demonstrated with reference to FIG. The arrows in FIG. 4 indicate the flow direction of the molten metal bath 3. The hatched arrow indicates that the molten metal bath 3 contains dross and is not cleaned, and the white arrow indicates that the molten metal bath 3 is cleaned after the dross is settled and removed.
[0059]
In the upper region 3A, the molten metal bath 3 flows along with the traveling metal strip 1, and flows out from the upper side of the enclosure 8b on the metal member 1 pulling side of the enclosure member 8 to the lower region 3B. Since there is an accompanying flow due to the rotation of the sink roll 4 in the area below the sink roll 4 in the upper area 3A, sufficient flow of the molten metal bath 3 is ensured even in the area where the metal strip 1 is not passed.
[0060]
In the upper region 3A, iron (Fe) is eluted from the steel strip 1 which is a metal strip, and fine Fe—Zn-based dross is generated. Part of the fine dross adheres to the metal strip 1 and is taken out of the molten metal bath 3. Even if this fine dross adheres to the metal strip 1, there is no problem in quality. Fine dross in the molten metal bath 3 that has not been taken out from the molten metal bath 3 flows into the lower region from the upper side of the enclosure 8b on the metal band 1 pulling side of the enclosure member 8 due to the flow accompanying the metal band 1 to be passed through. It is quickly discharged to 3B and does not settle or deposit in the upper region 3A.
[0061]
A molten metal bath 3 containing fine dross flows from the upper region 3A into the lower region 3B. The molten metal bath 3 containing fine dross that has flowed into the lower region 3B flows downward along the side wall 2a of the molten metal bath 2 on the metal band 1 pulling side, and further below and on the side of the surrounding member 8 It flows to the metal band 1 drawing-in part side (snout 7 side) of the molten metal bathtub 2 through the direction.
[0062]
The lower region 3B has a larger capacity than the upper region 3A and is not directly affected by the metal band 1 accompanying flow in the upper region 3A, so that the flow of the molten metal bath 3 is gentle. Therefore, the dross contained in the molten metal bath 3 settles at the bottom of the molten metal bath 2 while the molten metal bath 3 that has flowed into the lower region 3B flows to the metal band 1 lead-in portion side (snout 7 side). The dross settled and deposited on the bottom of the molten metal bath 2 grows into a large dross 16 that aggregates and influences the quality of the metal strip. Since the flow is slow in the lower region 3B, the large dross 16 deposited on the bottom of the molten metal bath 2 is difficult to be rolled up even if the metal strip 1 plate speed changes, or the dross rolled up even if it is wound up temporarily. 16 quickly settles to the bottom of the molten metal bath 2. Therefore, the molten metal bath 3 is clean in the region of the lower region 3B on the metal band 1 drawing side. In particular, the supernatant bath on the upper side of the bath surface is cleaner, and the large dross 16 that affects the metal strip quality is not floating.
[0063]
The supernatant bath of the molten metal bath 3 thus cleaned flows into the upper region 3A from above the enclosure 8a on the metal band 1 drawing side of the enclosure member 8 by the accompanying flow of the metal band 1 to be passed. The metal strip 1 is drawn into the molten metal bath 3 from the snout 7, and the direction is changed in the upper region 3 </ b> A by the sink roll 4 while being accompanied by the cleaned molten metal bath 3, and is pulled up from the molten metal bath 3. Since there is no dross 16 that affects the quality of the metal strip 1 through the region where the metal strip 1 is drawn into the molten metal bath 3 and pulled up from the molten metal bath 3, the metal pulled up from the molten metal bath 3 Adherence of dross 16 having a quality influence on the surface of the belt 1 is prevented.
[0064]
The surrounding member 8 is preferably installed so that the closest distance between the sink roll 4 and the metal strip 1 is 50 mm or more and 400 mm or less. If it is less than 50 mm, the contact with the metal band 1 due to thermal deformation or the positioning of the surrounding member 8 becomes difficult, and if it exceeds 400 mm, the influence of the wake of the metallic band 1 in the surrounding member 8 is affected. This is because a region that does not reach is generated, and the dross generated in the surrounding member 8 is difficult to be taken out to the lower region 3B outside the surrounding member 8, and the dross is accumulated inside the surrounding member 8 (in the upper region 3A). .
[0065]
The enclosure member 8 can be provided so that the upper end of the enclosure is on the bath surface. In this case, an opening for introducing the molten metal bath 3 in the lower region 3B into the upper region 3A is provided in the bath surface portion of the enclosure 8a on the metal band 1 drawing side of the enclosing member 8 or in the middle of the bath. An opening through which the molten metal bath 3 in the upper region 3A flows out to the lower region 3B is provided in the bath surface portion of the encircling member 8 on the side where the metal band 1 is pulled up or in the bath portion near the bath surface. However, when the surrounding member 8 is on the bath surface, the operation of taking out the top dross generated on the bath surface in the surrounding member 8 out of the molten metal bathtub 2 becomes complicated, and the top dross adheres to the surrounding member 8; There is a possibility that the action of the present invention, in which the molten metal bath 3 in the upper region 3A flows out to the lower region 3B by the accompanying flow of the steel strip 1 and the clean molten metal bath 3 is introduced into the upper region 3A from the lower region 3B, is reduced. Therefore, it is preferable to provide the upper end of the surrounding member 8 below the bath surface. When the upper end of the enclosing member 8 is less than 100 mm from the bath surface, the bath surface is agitated by the accompanying flow of the steel strip 1 to increase the amount of top dross.
[0066]
Further, the accompanying flow of the metal strip 1 that passes through the upper region 3A affects the lower region 3B and prevents the dross accumulated at the bottom of the molten metal bath 2 in the lower region 3B from being rolled up. In view of the above, the upper end of each enclosure of the enclosure member 8 (the upper end of the metal band pull-in side 8a, the upper end of the enclosure 8b on the metal band pull-up side, and the upper end of the enclosure 8c in the metal band width direction) is more than the axis of the sink roll 4 It is preferable that the upper side of the sink roll 4 is located above the uppermost part of the sink roll 4.
[0067]
The distance between the metal band drawing side enclosure 8a of the enclosure member 8 and the metal band 1 is preferably 1000 mm or less, and the distance between the metal band pulling side enclosure 8b and the metal band 1 is preferably 800 mm or less.
[0068]
The distance between the uppermost part of the sink roll 4 and the molten zinc bath surface is preferably 50 mm or more and 400 mm or less. If it is less than 50 mm, the bath surface is agitated by the rotation of the sink roll 4 and a large amount of top dross is generated, and if it exceeds 400 mm, a deep molten metal bath 2 is required, resulting in an increase in equipment costs.
[0069]
The distance between the lowermost part of the sink roll 4 and the bottom of the molten metal bath 2 is 400 mm or more (however, when the closest distance between the enclosure member 8 and the metal strip 1 is 50 mm or more and 400 mm or less, the enclosure member 8 is 400 mm or less. It is preferable that the value exceeds the value obtained by adding the thickness). This is because if it exceeds 400 mm, a sufficient dross precipitation portion cannot be secured at the bottom of the molten metal bath 2 and / or it becomes difficult to install the surrounding member 8 without contacting the sink roll 4 or the metal strip 1.
As described above, the main flow of the molten metal bath 3 in the molten metal bath 2 is unidirectional from the metal band 1 drawing side to the metal band 1 pulling side by the metal band 1 accompanying flow in the upper region 3A. It flows out into the lower region 3B from the enclosure 8b on the metal band 1 pulling side. In the lower region 3B, the molten metal bath 3 flows downward along the side wall 2a on the steel strip pulling side of the molten metal bath 2, and further flows to the metal band 1 drawing side through the lower and side of the surrounding member 8, The flow is directed in the opposite direction to the region 3A. As described above, the molten metal bath 3 circulates between the upper region 3A and the lower region 3B, and the starting force of the molten metal bath 3 circulation is substantially due to the accompanying flow of the metal strip 1 to be passed through. Since there is no need for equipment such as a pump for circulation, there is an advantage that the equipment can be simple and inexpensive.
[0070]
In the present invention, since the support roll 5 is not installed in the bath, the diameter of the sink roll 4 can be made larger than that of the conventional apparatus (FIG. 12) in which the support roll 5 is installed. FIG. 5 shows a case in which the sink roll 4 having a diameter of φ750 mm, which is a commonly used roll diameter, and the sink roll diameter is increased to φ950 mm, and is generated in a steel strip 1 having a width of 1200 mm by the gas wiping nozzle 6 parts. It is the result of investigating the amount of C warpage. The numerical value of the amount of C warpage of the steel strip 1 was + (plus) in the case of a convex shape on the sink roll 4 side, and − (minus) in the case of a convex shape on the opposite side of the sink roll 4.
[0071]
By increasing the diameter of the sink roll 4, the bending stress generated in the steel strip 1 wound around the sink claw 4 can be reduced. As a result, the steel when pulled up from the molten metal bath 3 as shown in FIG. The C warpage of the belt 1 can be reduced. As a result, the load of the shape correcting electromagnet can be reduced, and the shape of the molten metal bath 3 pull-up portion can be flattened even with respect to a thick steel strip that has conventionally been difficult to correct warpage. From this point, it is advantageous that the diameter of the sink roll 4 is 850 mm or more.
[0072]
Next, the shape correction device 9 will be described. The shape correcting device 9 is installed immediately after the gas wiping nozzle 6. Here, “immediately after the gas wiping nozzle 6” means that better control can be performed if the gas wiping nozzle 6 is close. In the actual line, an alloying furnace for alloying the plating film, a spangle adjusting device for adjusting spangle, etc. are provided above the gas wiping nozzle 6, and a touch for suppressing vibration of the metal strip 1 in front of the device. A roll may be provided. In this case, the shape correcting device 9 may be installed between the devices.
[0073]
FIG. 6 is a diagram showing a configuration of a shape correcting device 9 that corrects the shape of a metal band in a non-contact manner using an electromagnet installed in the device of FIG.
[0074]
The shape correction device 9 includes a position sensor 10 that measures the distance to the surface of the metal strip 1 that moves upward in the figure, a controller 11 that receives a signal from the position sensor 10 and outputs a control signal, and a control signal. It comprises an amplifier 12 that amplifies and an electromagnet 13 that changes the shape of the metal band by applying an attractive force to the metal band by the amplified control signal.
[0075]
A plurality of electromagnets 13 are provided in the width direction of the metal band 1, and are arranged in pairs on the front and back of the metal band 1. Since the electromagnet 13 exerts an attractive force in one direction with respect to the metal band 1, it is possible to correct the warp of the metal band 1 by selecting the attracting direction of the metal band 1 by being arranged on the front and back of the metal band 1. It is configured as follows.
[0076]
Normally, the warp shape in the width direction of the metal strip 1 is often C-shaped in cross section as shown in FIG. 1, and therefore the electromagnet 13 may be arranged at three locations (both edges and center) in the metal strip width direction. . Further, since the interference between the three position sensors 10 and between the electromagnets 13 is often not so large, each of the three positions may be constituted by independent control systems without compensating for the mutual interference. .
[0077]
Using this device, the controller 11 controls the attractive force of the electromagnets 13 arranged on the front and back of the metal band 1 based on a signal from the position sensor 10 that measures the distance to the surface of the metal band 1. Correct the warp of the metal strip 1. As a result, the warp of the metal strip 1 in the molten metal bath 3 pulling portion can be flattened.
[0078]
Next, a method for producing a hot dip galvanized steel strip using the above apparatus will be described. The steel strip 1 passes through the snout 7 and is drawn into the upper region 3A in the molten metal bath 3, and the sheet passing direction is changed by the sink roll 4 which is a direction changing roll, and is pulled up from the molten metal bath 3. Next, the amount of plating adhesion is adjusted by the gas wiping nozzle 6. The shape of the steel strip 1 of the gas wiping nozzle 6 is corrected by the shape correcting device 9 and flattened. Further, if necessary, the plating layer is alloyed in an alloying furnace (not shown), spangled with a spangle adjusting device, or cooled as it is to produce a required hot dip galvanized steel strip.
[0079]
Since the apparatus has an excellent effect of suppressing the adhesion of dross on the surface to the surface of the steel strip 1, the dross can be obtained without reducing the steel plate 1 plate speed, that is, without reducing the production efficiency. Can produce high quality hot dip galvanized steel strip without sticking.
[0080]
Further, since the warp in the width direction of the steel strip 1 is corrected at the gas wiping nozzle 6 part, the distribution of the amount of adhesion in the width direction of the steel strip 1 can be made uniform, and further, the gap between the gas wiping nozzle 6 and the steel strip 1 is narrowed, Splashing can be prevented by adjusting the amount of adhesion by reducing the gas pressure.
[0081]
In addition, since no support roll is installed, there is no quality defect caused by the support roll, and it is not necessary to stop the equipment for exchanging the support roll.
[0082]
It should be noted that dross 16 is deposited at the bottom of lower region 3B, that is, at the bottom of molten metal bath 2. The surrounding member 8 can be removed from the molten metal bath 2 and the accumulated dross 16 can be taken out of the molten metal bath 2 by means conventionally known.
[0083]
FIGS. 7-10 is a figure which shows other embodiment of the surrounding member 8 installed in the hot dip metal strip manufacturing apparatus of the 1st Embodiment of this invention. 7-10, the arrow in a bath shows the flow direction of a molten metal.
[0084]
In FIG. 7, the enclosure 8 b on the metal member 1 pulling side of the enclosure member 8 is configured to be substantially parallel to the pass line at a portion where the metal strip 1 is separated from the sink roll 4. In the upper region 3A, the flow velocity of the accompanying flow of the traveling of the metal strip 1 is maintained at a high speed until the molten metal bath 3 is discharged to the lower region 3B, so that the molten metal bath 3 in the upper region 3A is more efficient than the lower region 3B. Well leaked. It is preferable that the upper end of the enclosure 8b on the metal band 1 pulling side of the enclosure member 8 is higher than the uppermost part of the sink roll 4 and has a depth of 100 mm or more from the bath surface. When the upper end of the enclosure 8b on the metal belt 1 pulling portion side of the enclosure member 8 becomes higher than the uppermost part of the sink roll 4, the dross rolled up from the bottom of the molten metal bath 2 is likely to flow into the upper region 3A and becomes less than 100 mm from the bath surface. This is because the accompanying flow stirs the bath surface and increases the amount of top dross generated.
[0085]
In FIG. 8, in the surrounding member 8 shown in FIG. 7, a hoisting prevention plate 14 for preventing the hoisting of dross deposited and deposited in the lower region 3 </ b> B is provided outside the upper end of the encircling 8 b on the metal band 1 pulling side. Has been. By attaching the roll-up prevention plate 14, the dross deposited and deposited in the lower region 3B is wound up in the region on the metal band 1 pulling side of the upper region 3A by the flow of the molten metal bath 3 flowing out from the upper region 3A. Is prevented. From the viewpoint of suppressing the disturbance of the bath surface, the roll-up preventing plate 14 is preferably inclined obliquely forward with respect to the horizontal plane. The winding-up preventing plate 14 may also be installed at the upper end of the enclosure 8 a on the metal band 1 drawing side of the enclosure member 8 and the upper end of the enclosure 8 c on the metal band 1 end side.
[0086]
In FIG. 9, in the surrounding member 8 shown in FIG. 7, a winding prevention plate 14 similar to that attached to FIG. 8 is installed outside the upper end of the enclosure 8 b on the metal band 1 pulling side. In order to change the flow direction of the accompanying flow with the bath surface and to prevent the accompanying flow from disturbing the bath surface, the rectifying plate 15 is installed substantially parallel to the bath surface. The end of the current plate 15 on the side of the metal band 1 is preferably installed so as to be closer to the metal band 1 than the flow path of the accompanying flow in the upper region 3A in order to facilitate the direction change of the accompanying flow. However, in order to avoid contact with the metal strip 1, it is desirable to separate it from the metal strip 1 by 30 mm or more.
[0087]
In FIG. 10, the enclosing member 8 is provided with a rectifying structure 16 that separates the metal band 1 accompanying flow from the metal band 1 and prevents the accompanying flow from disturbing the bath surface. The rectifying structure 16 is installed at the place where the support rolls are arranged in the conventional apparatus.
[0088]
The enclosure 8b on the metal band 1 pulling side of the enclosure member 8 is configured to be inclined upward and outward, and a roll-up prevention plate 14 that performs the same function as the roll-up prevention plate 14 of FIG. .
[0089]
The rectifying structure 16 is attached between the metal band 1 pull-up side enclosure 8b and the pass line. The rectifying structure 16 is configured such that a side 16a facing the pass line is substantially parallel to the pass line, and a side 16b facing the metal band 1 pulling side enclosure 8b is substantially parallel to the metal band 1 pulling side enclosure 8b. Further, the upper portion 16c of the rectifying structure 16 is configured substantially horizontally, and a substantially horizontal rectifying plate 16d is attached to the side facing the enclosure 8b on the metal band 1 pulling side.
In the apparatus of FIG. 10, since the surrounding member 8 is configured as described above, it is separated from the metal band 1 without reducing the flow velocity of the metal band 1 accompanying flow in the region sandwiched between the surrounding 8b and the rectifying structure 16. And the accompanying flow does not disturb the bath surface. From the viewpoint of preventing contact with the metal strip 1, the distance between the rectifying structure 16 and the metal strip 1 is preferably 30 mm or more.
[0090]
FIG. 11 is a diagram showing a configuration of a hot-dip metal strip manufacturing apparatus according to the second embodiment of the present invention. This configuration is characterized in that the shape correcting device 9 is disposed immediately before the gas wiping nozzle 6 instead of the configuration shown in FIG. 3 in which the shape correcting device 9 is disposed immediately after the gas wiping nozzle 6. Here, the term “immediately before” means that the closer to the gas wiping nozzle 6, the better control can be performed, but in the actual line, it may be installed between the molten metal bath 3 and the gas wiping nozzle 6. The present apparatus can achieve the same effects as the apparatus shown in FIG.
[0091]
【Example】
(Example 1)
For the example of the present invention, a steel strip 1 having a width of 1200 mm and a thickness of 1.0 mm was applied to a steel strip 1 having a speed of 90 mpm and a tension of 2 kg / mm using the hot-dip metal strip manufacturing apparatus shown in FIG.²With a gas wiping nozzle 6, the adhesion amount per one side of the steel strip is 45 g / m.²The galvanized steel strip was manufactured by adjusting the gas pressure so that The sink roll 4 has a diameter of 800 mm, and an electromagnet 13 that corrects the C warp by a magnetic force (static magnetic field) provided at three positions in the width direction of the steel strip 1 immediately after the gas wiping nozzle 6 provided for wiping off excess zinc. It was installed at a position 20 mm away from the pass line. Using the shape straightening device 9 using the electromagnet 13, the electromagnets 13 of the electromagnets 13 correspond to the C warp amount of the steel strip 1 measured by the position sensor 10 so that the steel strip 1C warp amount at the gas wiping nozzle 6 is eliminated. Current adjustment was performed. The side facing the steel strip surface of the surrounding member 8 installed in the molten metal bath 3 was shaped so as to follow the sink roll 4, and the distance from the steel strip 1 was set to 150 mm at a minimum. The distance between the uppermost part of the sink roll 4 and the bath surface was about 600 mm.
[0092]
About the hot dip galvanized steel strip manufactured above, when the steel strip surface was observed with a 300 mm square sample, no dross could be confirmed. Also, the deviation of the adhesion amount in the width direction of the steel strip is about ± 5 g / m²Met.
[0093]
On the other hand, for comparison, in the apparatus having the support roll 5 shown in FIG. 12, the steel strip 1 having the same size as that described above was applied at a line speed of 90 mpm and the adhesion amount per one side of the steel strip was 45 g / m.²When a hot-dip galvanized steel strip was manufactured and adjusted in the same manner as described above, the deviation of the amount of adhesion in the width direction of the steel strip was about ± 10 g / m.²The number of dross of the 300 mm square sample was about 20 (conventional example). Further, in the apparatus shown in FIG. 3, when the enclosing member 8 in the bath is removed and a hot-dip galvanized steel strip is manufactured under the same conditions as in the present invention, the number of dross of the 300 mm square sample is about 10 pieces. Met. Deviation of the adhesion amount in the width direction of the steel strip 1 is about ± 5 g / m²(Comparative example).
[0094]
As described above, in the present invention example, dross attached to the steel strip 1 is suppressed and the amount of adhesion in the width direction of the steel strip 1 is made more uniform than in the conventional example. In the comparative example, since the surrounding member 8 is removed, the generation of dross is not suppressed.
[0095]
(Example 2)
For the inventive example, a steel strip 1 having a width of 1200 mm and a thickness of 1.0 mm was applied to a steel strip 1 having a speed of 90 mpm and a tension of 2 kg / mm using the molten metal plating apparatus shown in FIG.²With a gas wiping nozzle 6, the adhesion amount per one side of the steel strip is 45 g / m.²The galvanized steel strip was manufactured by adjusting the gas pressure so that The sink roll 4 has a diameter of 950 mm, and an electromagnet 13 that corrects the warp of the steel strip 1C by a magnetic force (static magnetic field) provided at three locations in the width direction of the steel strip 1 immediately after the gas wiping nozzle 6 provided to wipe off excess zinc. It was installed at a position 20 mm away from the pass line. Using the shape correction device 9 using the electromagnet 13, the current adjustment of each electromagnet 13 is performed according to the C warpage amount of the steel strip 1 measured by the position sensor 10 so that the C warpage amount at the gas wiping nozzle portion is eliminated. went. The side facing the steel strip surface of the enclosure 8 installed in the molten metal 3 was shaped so as to follow the sink roll 4, and the distance from the steel strip 1 was set to a minimum of 100 mm. The distance between the uppermost part of the sink roll 4 and the bath surface was about 200 mm.
[0096]
About the hot dip galvanized steel strip manufactured above, when the steel strip surface was observed with a 300 mm square sample, no dross could be confirmed. Also, the deviation of the adhesion amount in the width direction of the steel strip is about ± 5 g / m²Met.
[0097]
On the other hand, for comparison, in the apparatus having the support roll 5 shown in FIG. 12, the steel strip 1 having the same size as that described above was applied at a line speed of 90 mpm and the adhesion amount per one side of the steel strip was 45 g / m.²When a hot-dip galvanized steel strip was manufactured and adjusted in the same manner as described above, the deviation of the amount of adhesion in the width direction of the steel strip was about ± 10 g / m.²The number of dross of the 300 mm square sample was about 17 (conventional example). Further, in the apparatus shown in FIG. 3, when the enclosing member 8 in the bath is removed and a hot-dip galvanized steel strip is produced under the same conditions as in the present invention example, the number of dross of the 300 mm square sample is about 14 pieces. Met. Deviation of the adhesion amount in the width direction of the steel strip is about ± 4 g / m²(Comparative example).
[0098]
【The invention's effect】
As described above, according to the present invention, since the hot-dip metal strip can be manufactured without using the support roll in the bath, the hot-dip metal strip without defects caused by the support roll in the bath can be manufactured. Moreover, since the maintenance of the support roll in the bath becomes unnecessary, the production efficiency of the hot-dip metal strip can be increased. Moreover, since the maintenance of the support roll in the bath becomes unnecessary, the maintenance cost can be reduced.
[0099]
In addition, according to the present invention, even if it is a thick metal band, it is possible to flatten the warp of the metal band in the gas wiping nozzle portion, and to manufacture a hot-dip metal band with a uniform adhesion amount in the metal band width direction. .
[0100]
In addition, according to the present invention, since the effect of suppressing the occurrence of quality defects due to dross adhesion is excellent, a high-quality hot-dip metal strip without dross defects without reducing the metal strip passing speed, that is, without reducing the production efficiency. Can be manufactured.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a metal band width direction warpage generating mechanism.
FIG. 2 is a view for explaining a warp correction function of a support roll.
FIG. 3 is a diagram showing a configuration of a hot-dipped metal strip manufacturing apparatus according to the first embodiment of the present invention.
4 is a view for explaining the operation of an enclosing member provided in the apparatus of FIG. 3;
FIG. 5 is a diagram showing a relationship between a sink roll diameter and a steel strip C warpage amount.
FIG. 6 is a diagram showing a configuration of a shape correction device using an electromagnet.
FIG. 7 is a view showing another embodiment of an enclosing member installed in the hot-dip plated metal strip manufacturing apparatus according to the first embodiment of the present invention.
FIG. 8 is a view showing another embodiment of an enclosing member installed in the hot-dipped metal strip manufacturing apparatus according to the first embodiment of the present invention.
FIG. 9 is a view showing another embodiment of an enclosing member installed in the hot-dip plated metal strip manufacturing apparatus according to the first embodiment of the present invention.
FIG. 10 is a view showing another embodiment of an enclosing member installed in the hot-dipped metal strip manufacturing apparatus according to the first embodiment of the present invention.
FIG. 11 is a diagram showing a configuration of a hot dipped metal strip manufacturing apparatus according to a second embodiment of the present invention.
FIG. 12 is a diagram showing a configuration of a conventional hot-dip metal strip manufacturing apparatus.
[Explanation of symbols]
1 Metal strip (steel strip)
2 Molten metal bathtub
3 Molten metal bath
4 direction change roll (sink roll)
5 Support roles
6 Wiper (gas wiping nozzle)
7 Snout
8 Enclosing member
8a Enclosure on enclosing member's metal band drawing side
8b Enclosure on the metal band drawer side of the enclosing member
8c Enclosure on the metal band end side (sink roll axial direction side) of the enclosing member
9 Shape correction device
10 Position sensor
11 Controller
12 Amplifier
13 Electromagnet
14 Roll-up prevention plate
15 Current plate
16 Rectification structure

Claims

A drawing step of drawing the metal strip into a molten metal bath that is a plating metal and attaching the molten metal to the metal strip;
By the surrounding member formed so as to surround the metal strip drawn into the molten metal bath, the molten metal bath is divided into an upper region and a lower region in a state where the molten metal can flow, and the metal strip Is a direction of turning by the direction change roll in the upper region, and after the direction change, the pulling step to be pulled out of the molten metal bath without contacting the roll in the molten metal bath,
An adjusting step of adjusting the amount of adhesion of the molten metal by a wiper that wipes off the excess molten metal adhering to the metal band;
And a shape correcting step for correcting the shape of the metal band immediately before or after the wiper by a magnetic force in a non-contact manner, and a surrounding member of the lifting step is any of the following (A) to (D) A method for producing a hot-dip plated metal strip.
(B) The enclosure on the metal band pulling side is configured to be substantially parallel to the pass line at the portion where the metal band is separated from the sink roll, and the upper end of the metal band pulling side is higher than the uppermost part of the sink roll and The surrounding member comprised so that it might become 100 mm or more from a bath surface.
(B) A surrounding member in which a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is attached to the outside of the upper end of the encircling side of the metal band pulling side.
(C) A hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is provided outside the upper end of the enclosure on the metal band pulling side, and the hoisting prevention plate and the bath are further provided. An enclosing member in which a flow straightening plate for changing the flow direction of the accompanying flow with respect to the surface and preventing the accompanying flow from disturbing the bath surface is provided substantially parallel to the bath surface.
(D) The metal band lifting side enclosure is configured to be inclined upward and outward, and the metal band accompanying flow is separated from the metal band between the metal band lifting side enclosure and the pass line, and the accompanying flow is A rectifying structure is provided to prevent the bath surface from being disturbed, and the rectifying structure is substantially parallel to the pass line on the side facing the pass line, and the side facing the encircling side of the metal band pulling side is the metal band. An enclosing member configured to be substantially parallel to the enclosure on the pulling side.

2. The enclosure member according to claim 1, wherein the enclosure on the metal band lifting side is configured to be substantially parallel to the pass line at a portion where the metal band is separated from the sink roll and passed through the metal band. 2. The method of manufacturing a hot-dip metal strip according to claim 1, wherein the upper end of the encircling side on the side of the band is higher than the uppermost part of the sink roll and is 100 mm or more from the bath surface.

In Claim 1, the encircling member (d) is provided with a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the molten metal bath lower region outside the upper end of the encircling on the metal band raising side, 2. The hot dip plated metal according to claim 1, wherein an upper portion of the rectifying structure is substantially horizontal, and a substantially horizontal rectifying plate is provided on a side opposite to the metal band pulling side enclosure. Manufacturing method of the belt.

The molten metal bath containing dross generated in the upper region flows out from the side of the surrounding member where the metal band of the surrounding member is pulled out of the molten metal bath to the lower region, and in the lower region, the dross contained in the molten metal bath is discharged. The molten metal bath is cleaned by settling and removal, and the cleaned molten metal bath is introduced into the upper region from the side of the metal band of the surrounding member drawn into the molten metal bath. The manufacturing method of the hot dipped metal strip in any one of 1-3 .

The said enclosing member is provided under the molten metal bath surface, The manufacturing method of the hot dip metal strip in any one of Claims 1-4 characterized by the above-mentioned.

The method for manufacturing a hot-dip metal strip according to any one of claims 1 to 5 , wherein the closest distance between the direction change roll and the surrounding member is 50 mm or more and 400 mm or less.

The method for producing a hot-dip metal strip according to any one of claims 1 to 6 , wherein an interval between the uppermost part of the direction change roll and the molten metal bath surface is 50 mm or more and 400 mm or less.

The method for manufacturing a hot-dip metal strip according to any one of claims 1 to 7 , wherein an outer diameter of the direction change roll is 850 mm or more.

The distance between the lower surface of the direction change roll and the bottom of the molten metal bath is 400 mm or more (in the case of claim 6 , it exceeds 400 mm plus the thickness of the surrounding member). method of manufacturing a hot-dip coating metal strip according to any one of 1 to 8.

In an apparatus for manufacturing a hot-dip metal strip by drawing the hot metal into a bath of hot metal that is a plating metal,
A roll that holds the molten metal and adheres the molten metal to the metal band, and has a direction changing roll that changes the direction of the metal band in the molten metal bath, and is in contact with the metal band after the direction change. A molten metal bathtub without
The molten metal bath is formed so as to surround a metal strip drawn into the molten metal bath and to divide the molten metal bath into an upper region and a lower region in a state in which the molten metal can flow. A surrounding member formed such that the metal strip redirected by the redirecting roll in the region is pulled out of the molten metal bath;
A wiper that adjusts the amount of adhesion by wiping away excess molten metal adhering to the metal strip;
And wherein the Rutotomoni a straightening device for straightening the shape of the metal strip just before or just after the wiper in a non-contact manner by a magnetic force, wherein the enclosing member is either of the following (a) to (d) Manufacturing equipment for hot-dip plated metal strips.
(B) The enclosure on the metal band pulling side is configured to be substantially parallel to the pass line at the portion where the metal band is separated from the sink roll, and the upper end of the metal band pulling side is higher than the uppermost part of the sink roll and The surrounding member comprised so that it might become 100 mm or more from a bath surface.
(B) A surrounding member in which a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is attached to the outside of the upper end of the encircling side of the metal band pulling side.
(C) A hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath is provided outside the upper end of the enclosure on the metal band pulling side, and the hoisting prevention plate and the bath are further provided. An enclosing member in which a flow straightening plate for changing the flow direction of the accompanying flow with respect to the surface and preventing the accompanying flow from disturbing the bath surface is provided substantially parallel to the bath surface.
(D) The metal band lifting side enclosure is configured to be inclined upward and outward, and the metal band accompanying flow is separated from the metal band between the metal band lifting side enclosure and the pass line, and the accompanying flow is A rectifying structure is provided to prevent the bath surface from being disturbed, and the rectifying structure is substantially parallel to the pass line on the side facing the pass line, and the side facing the encircling side of the metal band pulling side is the metal band. An enclosing member configured to be substantially parallel to the enclosure on the pulling side.

11. The enclosure member of (b) or (c), wherein the enclosure on the metal band lifting side is configured to be substantially parallel to the pass line at a portion where the metal band is separated from the sink roll, 11. The apparatus for producing a hot-dip metal strip according to claim 10, wherein the upper end of the enclosure on the side of raising the belt is higher than the uppermost part of the sink roll and is 100 mm or more from the bath surface.

The encircling member according to claim 10, wherein the encircling member (d) is provided with a hoisting prevention plate for preventing the hoisting of dross deposited and deposited in the lower region of the molten metal bath on the outer side of the encircling upper end on the metal band raising side. The hot-dip plated metal according to claim 10, wherein the upper part of the rectifying structure is substantially horizontal, and a substantially horizontal rectifying plate is provided on the side facing the enclosure on the side where the metal band is pulled up. Band manufacturing equipment.

The surrounding member is configured such that a molten metal bath containing dross generated in the upper region flows out from the surrounding portion side on the pulling side of the metal strip to the outside of the molten metal bath, and the molten metal of the metal strip 10. from pulling side of the enclosing portion into the bath, the the dross in the lower region, characterized in that it is configured to a molten metal bath which has been cleaned is removed sedimentation is introduced into the upper region The manufacturing apparatus of the hot dipped metal strip in any one of -12 .

The apparatus for producing a hot-dip metal strip according to any one of claims 10 to 13, wherein the surrounding member is provided below the surface of the hot metal bath.

The apparatus for producing a hot-dip metal strip according to any one of claims 10 to 14 , wherein a closest distance between the direction change roll and the surrounding member is 50 mm or more and 400 mm or less.

The apparatus for producing a hot dipped metal strip according to any one of claims 10 to 15 , wherein a distance between the uppermost part of the direction change roll and the molten metal bath surface is 50 mm or more and 400 mm or less.

17. The apparatus for producing a hot-dip metal strip according to claim 10 , wherein an outer diameter of the direction change roll is φ850 mm or more.

The distance between the lower surface of the direction change roll and the bottom of the molten metal bath is 400 mm or more (in the case of claim 15 , the distance exceeds 400 mm plus the thickness of the surrounding member). The apparatus for producing a hot dipped metal strip according to any one of 10 to 17 .