JP3908902B2 - Cooling drum for continuous casting of thin-walled slab and continuous casting method of thin-walled slab - Google Patents

Cooling drum for continuous casting of thin-walled slab and continuous casting method of thin-walled slab Download PDF

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JP3908902B2
JP3908902B2 JP2000306764A JP2000306764A JP3908902B2 JP 3908902 B2 JP3908902 B2 JP 3908902B2 JP 2000306764 A JP2000306764 A JP 2000306764A JP 2000306764 A JP2000306764 A JP 2000306764A JP 3908902 B2 JP3908902 B2 JP 3908902B2
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drum
thin
scum
cooling
peripheral
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JP2002113559A (en
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英明 山村
泰 栗栖
雅文 宮嵜
栄一 竹内
忠浩 伊豆
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Nippon Steel Corp
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Nippon Steel Corp
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【0001】
【発明の属する技術分野】
本発明は、普通鋼、ステンレス鋼、合金鋼、珪素鋼及びその他の鋼や合金、金属の溶湯から、直接、薄肉鋳片を鋳造する、単ドラム式連続鋳造機または双ドラム式連続鋳造機の冷却ドラムの表面構造及び表面材質に関するものである。
【0002】
【従来の技術】
一対の冷却ドラム(以下「ドラム」ということがある。)を備えた双ドラム式連続鋳造装置、または、一個の冷却ドラムを備えた単ドラム式連続鋳造装置により、板厚1〜10mmの薄肉鋳片(以下「鋳片」ということがある。)を連続鋳造する技術が開発されている。
【0003】
この技術は、最終製品に近い形状と肉厚の薄肉鋳片を製造するものであるから、歩留り良く、所要レベルの品質を有する最終製品を最終的に得るために、該技術に対しては、割れや亀裂等の表面欠陥や、酸洗むらが皆無の鋳造鋳片を得ることが不可欠のこととして要求される。
特に、ステンレス鋼の薄板製品においては、高品質の表面性状が求められるので、酸洗むらのない薄肉鋳片を鋳造することが大きな課題となる。
【0004】
この表面欠陥は、薄肉鋳片を連続鋳造する際、冷却ドラムの表面において、凝固シェルの生成が一様でない、即ち、溶鋼の急冷・凝固の態様が一様でないことに起因する熱収縮応力の不均衡に基づいて形成されるものであることが知られていて、これまで、この熱収縮応力の不均衡が鋳片内部に極力残らないように溶鋼を冷却、凝固せしめる冷却ドラムの周面構造が種々提案されている。
【0005】
例えば、特開平4−238651号公報には、周面に50〜200μmの深さの窪みを15〜30%の面積率で形成するとともに、10〜50μmの深さの窪みを40〜60%の面積率で形成した連続鋳造用の冷却ドラムが開示されている。また、特開平6−328204号公報には、周面に直径100〜300μm、深さ100〜500μmの窪みを15〜50%の面積率で形成するとともに、直径400〜1000μm、深さ10〜100μm、周面の接線に対し垂直な線と窪みの側面とのなす角度が45〜75°の窪みを40〜60%の面積率で形成した連続鋳造用の冷却ドラムが開示されている。
【0006】
そして、これらの冷却ドラムは、鋳片表面における表面割れや亀裂の発生を抑制するとともに、もう一方の代表的な表面欠陥である酸洗むらの発現を抑制するもので、光沢むらのないステンレス鋼薄板製品を製造する上において、顕著な効果を奏するものである。
また、特開平11−179494号公報には、周面に多数の突起(好ましくは、高さ20μm以上、直径0.2〜1.0μm、最近接間隔0.2〜1.0mm)を形成した連続鋳造用の冷却ドラムが開示されている。この冷却ドラムは、薄肉鋳片の連続鋳造において、表面欠陥を皆無に近い状態にまで抑制できるものである。
【0007】
さらに、特開平9−103849号公報には、周面に、Ni層と厚み10〜500μmのCo層とが順に形成されており、該Ni層とCo層の厚みの和が500μm〜2mmであり、該Co層の表面には平均深さ30〜150μmの窪みが形成されている冷却ドラムが開示され、また、特開平9−103850号公報には、周面にNi層を形成し、該Ni層にショットブラスト処理を施して平均深さ10〜50μmの窪みを設けた後、厚み10〜500μmの電気メッキを施し、該窪みの平均深さを30〜150μmにした冷却ドラムが開示されている。
【0008】
これらの冷却ドラムは、ドラムの周面構造及び周面材質を改善・工夫することにより、薄肉鋳片における割れの発生の抑制や、ドラム寿命の延長を図ったもので、顕著な効果を奏するものである。
このように、板厚1〜10mmの薄肉鋳片を連続鋳造する技術においては、冷却ドラムの周面構造や周面材質を改善・工夫することにより、酸洗むらを含む表面欠陥を抑制するのに、大きな成功を納めている。
【0009】
しかしながら、操業中、冷却ドラムとその両側に当接するサイド堰で形成される溶鋼を受容する湯溜まり部を不活性雰囲気で包囲し、スカムの生成をできるだけ抑制しても、溶鋼の内部から、介在物や混入したスラグが浮上したりして、相当量のスカムが、溶鋼表面上に浮遊し、凝集することは避けられない。そして、このスカムが冷却ドラムと溶鋼の間に巻き込まれて、薄肉鋳片の表面に酸洗むらが発現する。
【0010】
この酸洗むらの部分は、最終薄板製品においては、光沢むらとして発現し、製品素材としての価値を低めるから、最終薄板製品の品質と歩留りを、さらに高めるためには、薄肉鋳片を連続鋳造する際、スカムの生成を極力抑制することに加え、スカムが巻き込まれても、薄肉鋳片に酸洗むらが発生するのを極力抑制できる、できれば該発生を皆無にすることができる、何らかの対策が必要とされている。
【0011】
そこで、本発明者は、その対策を探るべく、酸洗むらが発現した薄肉鋳片について詳細に調査した。その結果、本発明者は、酸洗むらが発現した領域とそうでない領域との境界近傍に、従前知られている表面割れとは形態の異なる“割れ”が発生しているのを発見した。この“割れ”(以下「酸洗むら付随割れ」という。)を、図1に示す。
【0012】
図1から分かるように、“酸洗むら付随割れ”は、酸洗むらの発生していない部位で発生する表面割れ(以下「ディンプル割れ」ということがある。)とは、当然に、割れの起源、位置、形態等の点で異質なものである。
したがって、これまでの手段では、上記異質な“酸洗むら付随割れ”を防止することは困難である。
【0013】
このように、薄肉鋳片の連続鋳造においては、“ディンプル割れ”及び“酸洗むら”の発生を抑制するという課題の他に、“酸洗むら付随割れ”の発生を抑制するという課題を、新たに抱えることになった。
【0014】
【発明が解決しようとする課題】
そこで、本発明は、薄肉鋳片の連続鋳造において、“ディンプル割れ”の発生を抑制するとともに、“酸洗むら”及び“酸洗むら付随割れ”の発生を抑制することを課題とし、該課題を、溶鋼の凝固態様に大きく影響する冷却ドラムの周面周面構造及び周面材質の点から解決することを目的とするものである。
【0015】
【課題を解決するための手段】
酸洗むらは、スカムが付着した部位において溶鋼の凝固が遅れ、その結果、スカム付着部の凝固組織が、その周辺の凝固組織と異なるものになることに起因して、酸洗後、鋳片表面に“むら”として発現したものであるから、冷却ドラムの表面上での溶鋼の凝固態様が、“酸洗むら付随割れ”の発生にも、大きく関与しているものと推測される。
【0016】
そこで、本発明者は、まず、図1に示すような“酸洗むら付随割れ”が発生した薄肉鋳片の凝固態様について調査したところ、“酸洗むら付随割れ”は、基本的には、スカムの流入、付着によって、冷却ドラムと溶鋼との界面の熱抵抗が変化し、スカムが付着した部位とそうでない部位とで、形成される凝固シェルの厚さに差が生じることに起因するものであるところ、具体的には、凝固シェル厚の不均一度が20%を超える部位で発生していることが判明した。
【0017】
図2に、その発生機構を模式的に示す。スカム1が付着した部位では、冷却ドラム10と溶鋼9との界面における熱抵抗が変化し、溶鋼の凝固が遅れるので、凝固シェル2の厚さは、他の部位における凝固シェルの厚さより薄いものとなるが、スカム1とディンプル3の凹面との間に形成されるガスギャップ4との相乗作用により、厚い凝固シェルと薄い凝固シェルとの境界部(凝固シェル厚の不均一部分)に、“歪み”が発生し、蓄積される。そして、この凝固シェル厚の不均一度が、20%を超えると、図2に示すように、上記境界部で“酸洗むら付随割れ5”が発生する。
【0018】
上記のように、“酸洗むら付随割れ5”の原因となる“歪み”の発生、蓄積には、スカム1とディンプル3の凹部との間に形成されるガスギャプ4の存在も関連しているので、本発明者は、さらに、ディンプルの“深さ”を変えることにより溶鋼の凝固態様を変化させ、凝固態様の変化(この変化を示す指標として、“ディンプル深さ”を用いた。)と、“ディンプル割れ”及び“酸洗むら付随割れ”の発生状況(発生状況を示す指標として、“割れ長さ”を用いた。)との関連性を調査した。
【0019】
その結果を、図3に示す。この図によれば、ディンプルの深さ(μm)を浅くすれば、“ディンプル割れ”の発生を防止できるが、逆に、“酸洗むら付随割れ”の発生を助長することが分かる。
このように、本発明者は、“酸洗むら付随割れ”と“ディンプル割れ”の発生もしくは発生抑制は、冷却ドラムの周面に形成したディンプルの深さとの関係でみると、トレードオフの関係にあることを見いだした。
【0020】
ここで、図4に、“ディンプル割れ”の発生機構を模式的に示す。ディンプル3の頂部に当接した溶鋼部位に凝固核が生成し(図中「6」参照)、ここから凝固が進行するが、ディンプル3の凹部に侵入して形成される溶鋼の凸部7が凝固するとき、凝固はディンプル単位で比べると不均一であり、この不均一に起因して、ディンプル単位毎に不均一応力・歪みが蓄積される。そして、この不均一応力・歪みが原因となって、“ディンプル割れ8”が発生する。
【0021】
溶鋼の凸部7が凝固するとき、スカム1が付着した部位では、スカムが熱抵抗となり、当然に凝固が遅れるが、この場合、凝固の遅れにより、上記不均一応力・歪みが緩和される。
以上の調査結果から得られた知見をまとめると、以下のとおりである。
(a)溶鋼は、ディンプルの頂部に当接するが、ガスギャップの存在により、その底部には、完全に当接しない。
(b)ディンプルの頂部に当接した溶鋼は、頂部に当接していない溶鋼より速く凝固する。
(c)溶鋼とディンプル表面との間にガスギャップが存在すると、ガスギャップが熱抵抗として作用し、溶鋼の凝固が遅くなる。
(d)スカムが付着した溶鋼とディンプル表面との間にガスギャップが存在すると、スカムとガスギャップが熱抵抗として作用し、溶鋼の凝固がより遅くなる。その結果、スカムが付着した部位の凝固シェルの厚さと、そうでない部位の凝固シェルの厚さに差が生じ、厚み境界部に、不均一応力・歪みが蓄積される。これが、“酸洗むら付随割れ”の原因となる。
(e)“ディンプル深さ”が浅ければ、溶鋼のディンプル凹部への侵入高さ(凸部の高さ)は低いので、ディンプル単位毎の不均一応力・歪みの蓄積が緩和され、“ディンプル割れ”の発生が抑制されるが、逆に、スカムとガスギャップに基づく凝固遅れに起因する不均一応力・歪みの蓄積が助長され、“酸洗むら”とともに“酸洗むら付随割れ”が頻発する。
(f)“ディンプル深さ”が深ければ、溶鋼のディンプル凹部への侵入高さ(凸部の高さ)は高いので、ディンプル単位毎の不均一応力・歪みの蓄積が助長され、“ディンプル割れ”が頻発するが、逆に、スカムとガスギャップに基づく凝固遅れに起因する不均一応力・歪みの蓄積は緩和されるので、“酸洗むら”とともに“酸洗むら付随割れ”の発生が抑制される。
【0022】
そして、本発明者は、これらの知見に基づき、ディンプルの形態において、まず、“ディンプル割れ”を抑制できる“ディンプル深さ”を確保し、この“ディンプル深さ”を前提に、ディンプルの表面に、
(x)熱抵抗となるガスギャップを形成しない、
(y)頂部に当接した溶鋼の凝固を遅らせる、及び、
(z)底部に当接した溶鋼の凝固を促進する、
機能を付与すれば、従来、スカム付着部位での凝固遅れに基づき、凝固シェルの厚み境界部に蓄積される不均一応力・歪みを低減することができ、結果として、“ディンプル割れ”の発生、及び、“酸洗むら”と“酸洗むら付随割れ”の発生の両方を抑制できるのでないかとの発想に至った。
【0023】
そして、本発明者は、上記発想の下において、冷却ドラムの周面に形成するディンプルにおいて、上記(x)の機能を果たす表面について、鋭意、調査研究を行った。その結果、ガスギャップの存在は、冷却ドラムの表面とスカムとの濡れ性に大きく関係していて、
(X)冷却ドラム表面に、スカムとの濡れ性が良い物質が存在すると、スカムが該表面になじみ、ガスギャップが形成され難い、
との知見を得た。
【0024】
なお、冷却ドラムの表面には、通常、Niメッキが施されるが、スカムとの濡れ性が良い物質としてNi−W合金が好適であることが判明した。
さらに、本発明者は、同様に、上記(y)及び(z)の機能を果たす表面について、鋭意、調査研究を行った。その結果、
(Y)ディンプルの頂部に、所定形状の“丸み”をつけるか、もしくは、所定形状の“細孔”を形成すると、ディンプル頂部に当接した溶鋼の凝固を遅らせることができる、
との知見を得た。
【0025】
また、ガスギャップの形成を抑制し、かつ、ディンプルの頂部に“丸み”をつけたり“細孔”を形成したりすると、溶鋼は、冷却ドラムの圧下力の下で、容易にディンプルの底部に当接し、発生した凝固核を起点にして凝固するが、
(Z)ディンプルの底部に、“微小突起”を形成しておくと、凝固核の生成が促進されて、溶鋼の凝固がより速く進行する、
との知見を得た。
【0026】
本発明は、以上の知見に基づき、さらにディンプルの形状と、ディンプルの頂部に形成する“丸み”や“細孔”の形状、また、ディンプルの底部に形成する“微小突起”の形状との好ましい関係を確認してなされたものである。
そして、薄肉鋳片連続鋳造用冷却ドラムに係る発明の要旨は、以下のとおりである。
(1)薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されて窪みの頂部は鋭角的な形状をなしているとともに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。
(2)薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されて窪みの頂部は鋭角的な形状をなしているとともに、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該表面には、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。
(3)薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、高さが1〜50μm、円相当の径が30〜200μmの微小突起が、相互に隣接して形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。
(4)薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、高さが1〜50μm、円相当の径が5〜200μmの微小突起が、相互に隣接して形成され、かつ、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。
(5)薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、深さが5〜100μm、円相当の径が5〜200μmの細孔が形成され、かつ、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。
(6)前記スカムとの濡れ性がNiよりも良い物質が、連続鋳造される溶鋼を構成する元素と同一の元素の酸化物であることを特徴とする(1)、(2)、(3)、(4)または(5)記載の薄肉鋳片連続鋳造用冷却ドラム。
(7)前記スカムとの濡れ性がNiよりも良い物質が、冷却ドラム周面上のメッキを構成する元素の酸化物であることを特徴とする前記(1)、(2)、(3)、(4)または(5)記載の薄肉鋳片連続鋳造用冷却ドラム。
(8)前記スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が、冷却ドラム周面上のメッキが酸化して形成された皮膜であることを特徴とする(1)または(2)記載の薄肉鋳片連続鋳造用冷却ドラム。
(9)前記スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が、冷却ドラム周面上のメッキに、溶鋼中の成分元素が酸化して生成した酸化物が付着して形成された皮膜であることを特徴とする(1)または(2)記載の薄肉鋳片連続鋳造用冷却ドラム。
(10)前記メッキが、Niよりも酸化され易い元素を含むメッキであることを特徴とする前記(1)、(2)、(3)、(4)、(5)、(8)または(9)記載の薄肉鋳片連続鋳造用冷却ドラム。
(11)前記メッキが、W、Co、Fe、Crの1種または2種以上を含むメッキであることを特徴とする前記(1)、(2)、(3)、(4)、(5)、(8)または(9)記載の薄肉鋳片連続鋳造用冷却ドラム。
【0027】
また、前記(1)〜(11)のいずれかに記載の薄肉鋳片連続鋳造用冷却ドラムを用いる連続鋳造方法に係る発明の要旨は、以下のとおりである。
(12)一方向に回転する、前記(1)〜(11)のいずれかに記載の薄肉鋳片連続鋳造用冷却ドラムの周面上に溶鋼を注入し、該溶鋼を該冷却ドラムの周面上で冷却、凝固させ、薄肉鋳片を連続鋳造することを特徴とする薄肉鋳片の連続鋳造方法。
(13)平行に配置され互いに逆方向に回転する一対の、前記(1)〜(11)のいずれか1項に記載の薄肉鋳片連続鋳造用冷却ドラムの周面の一部に湯溜り部を形成し、該湯溜り部に注入した溶鋼を、該冷却ドラムの周面上で冷却、凝固させ、薄肉鋳片を連続鋳造することを特徴とする薄肉鋳片の連続鋳造方法。
【0028】
【発明の実施の形態】
本発明について、さらに詳細に説明する。
本発明の薄肉鋳片連続鋳造用冷却ドラム(以下「本発明の冷却ドラム」という。)は、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜が形成されていることを基本的な技術思想とする。
【0029】
これは、前記知見に従い、メッキが施されたドラム周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜を形成することにより、冷却ドラムの周面に、該周面と溶鋼との間で熱抵抗となるガスギャップの生成を極力抑制することができる機能を付与したものである。
冷却ドラムの周面上で、凝固シェルが形成される際、スギャップが存在しなければ、スカムが流入し、スカムが付着した部位の溶鋼の凝固が遅れても、スカムが付着していない溶鋼の凝固との間に、“酸洗むら付随割れ”を誘起するに足る凝固不均一は生じない。
【0030】
通常、薄肉鋳片連続鋳造用冷却ドラムの表面には、緩冷却化と長寿命化(熱応力による表面の亀裂の発生防止)のために、Cuより熱伝導率が低く、かつ、硬くて熱応力に強いNiメッキを施すが、該メッキは、Niよりも酸化され易い元素、例えば、W、Co、Fe、Crの1種または2種以上を含むメッキであることが好ましい。
【0031】
本発明の冷却ドラムにおいては、ドラムの表面における緩冷却化と長寿命化を維持しつつ、スカムとの濡れ性を改善するため、該表面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜を形成する。
スカムは、溶鋼を構成する元素の酸化物の凝集体であるから、上記スカムとの濡れ性がNiよりも良い物質としては、連続鋳造される溶鋼を構成する元素の酸化物が好ましい。
【0032】
そして、上記スカムとの濡れ性がNiよりも良い物質を含む皮膜は、溶鋼を構成する元素の酸化物を、スプレーやロールコーター等の手段で、冷却ドラムのメッキ周面に被覆した皮膜でもよいし、また、操業中、冷却ドラム周面上のメッキに、溶鋼中の成分元素が酸化して生成した酸化物が付着して形成された皮膜でもよい。
【0033】
また、上記スカムとの濡れ性がNiよりも良い物質は、冷却ドラム周面上のメッキを構成する元素の酸化物であってもよい。これは、冷却ドラム周面上のメッキが溶鋼の熱で酸化されて生成した酸化物は、スカムとの濡れ性が、該メッキよりも良いからである。
それ故、実際には、冷却ドラム周面上に、改めて、メッキを構成する元素の酸化物の皮膜を形成する必要はなく、操業中、溶鋼の熱で冷却ドラムの周面上に形成されたメッキの酸化物をそのまま残して使用することができる。
【0034】
本発明の冷却ドラムにおいては、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されている。
窪み(ディンプル)の平均深さは40〜200μmとする。この平均深さが40μm未満であると、ディンプルによるマクロな応力歪みの緩和効果が得られないので、下限は40μmとする。一方、平均深さが200μmを超えると、ディンプル底部への溶鋼の侵入が不充分となり、ディンプルの不均一性が増大するので、上限は200μmとする。
【0035】
窪みの大きさは、円相当の径で0.5〜3mmとする。この径が0.5mm未満であると、ディンプル底部への溶鋼の侵入が不充分となり、ディンプルの不均一性が増大するので、下限は0.5mmとする。一方、円相当の径が3mmを超えると、ディンプル単位での応力・歪みの蓄積量が多くなり、ディンプル割れが発生し易くなるので、上限は3mmとする。そして、本発明の冷却ドラムにおいては、上記形状の窪みを、窪みの頂部を介して相互に隣接して形成する。
【0036】
このような窪みを形成すると、窪みそれぞれが、凝固シェルに働く応力・歪みを分散化することができ、凝固シェルに働くマクロな応力・歪みを低減することが可能となる。
本発明の冷却ドラムにおいては、上記形状の窪みの表面に、高さが1〜50μm、円相当の径が5〜200μmの微小突起を形成することが好ましい。この微小突起により、窪みの表面に当接した溶鋼の凝固を促進することができる。
【0037】
高さが1μm未満であると、突起が溶鋼と充分に接触することができず、凝固核の生成が起こらず、溶鋼の凝固を促進することができないので、下限は1μmとする。一方、高さが50μmを超えると、突起底部での溶鋼の凝固が遅れ、窪み内での凝固シェルの不均一が発生するので、上限は50μmとする。
また、円相当の径が5μm未満であると、突起での冷却が不充分となり、凝固核の生成が起こらないので、下限は5μmとする。一方、円相当の径が200μmを超えると、突起への溶鋼の接触が不充分な部位が発生し、凝固核の生成が不均一となるので、上限は200μmとする。
【0038】
そして、上記微小突起は、スカムとの濡れ性がNiよりも良い物質を含む皮膜が形成されているものである。
また、本発明の冷却ドラムにおいて、上記スカムとの濡れ性がNiよりも良い物質を含む皮膜が形成されている微小突起は、溶鋼中の成分元素が酸化して生成した酸化物が付着した微小突起であってもよい。上記微小突起に、溶鋼中の成分元素が酸化して生成した酸化物が付着することにより、微小突起とスカムとの濡れ性がより向上し、該微小突起に当接した溶鋼部位において、より多くの凝固核発生起点の生成を促し、溶鋼の凝固を速めることができる。
【0039】
本発明の冷却ドラムにおいては、上記形状の窪みの頂部に、高さが1〜50μm、円相当の径が30〜200μmで、スカムとの濡れ性がNiよりも良い物質を含む皮膜が形成されている微小突起が、相互に隣接して形成されていることが好ましい。
ディンプルを形成したままのディンプルの頂部は、鋭角的な形状をなしているが、該頂部に、多数の上記微小突起を相互に隣接した態様で形成することとにより、“丸み”をつけることができる。この“丸み”により、ディンプルの頂部に当接した溶鋼においては、凝固核の生成が遅延し、凝固の進行が遅れることになる。また、上記“丸み”を帯びたディンプル頂部は、ディンプルの凹部に溶鋼が侵入するのを促進する作用をなす。その結果、溶鋼は、溶鋼の静圧や冷却ドラムの圧下力の下で、容易にディンプルの底部に当接することになる。
【0040】
高さが1μm未満であると、ディンプル頂上部での凝固核生成の遅延効果が得られないので、下限は1μmとする。一方、高さが50μmを超えると、ディンプル底部への溶鋼の侵入が不充分となるので、上限は50μmとする。
また、円相当の径が、30μm未満であると、ディンプル頂上部での凝固核生成の遅延効果が得られないので、下限は30μmとする。一方、円相当の径が200μmを超えると、ディンプルによる応力・歪みの緩和効果が得られないので、上限は200μmとする。
【0041】
さらに、ディンプルを形成したままで、鋭角的な形状をなしているディンプルの頂部に、微小突起の替わりに、深さが5μm以上、円相当の径が5〜200μmの“細孔”を形成することが好ましい。この“細孔”の形成により、ディンプルの頂部における鋭角的な形状が消滅するとともに、ガスを保持する緩冷却部(エアギャップ)が形成されるので、“細孔”を有するディンプル頂部は、該頂部に当接した溶鋼における凝固核の生成を遅延せしめ、凝固の進行を遅くらせる作用をなす。また、“細孔”を有するディンプル頂部は、ディンプルの凹部に溶鋼が侵入するのを促進する作用をなす。その結果、溶鋼は、溶鋼の静圧や冷却ドラムの圧下力の下で、容易にディンプルの底部に当接することになる。
【0042】
深さが5μm未満であると、細孔部でのエアギャップの形成が不充分となり、凝固核生成の遅延効果が得られないので、下限は5μmとする。
また、円相当の径が5μm未満であると、細孔部以外の頂上近傍で凝固核が生成し、ディンプル底部への溶鋼の侵入促進効果が得られないので、下限は10μmとする。一方、円相当の径が200μmを超えると、ディンプル頂上部の高さが見かけ上低くなり、応力・歪みの緩和効果が得られないので、上限は200μmとする。
【0043】
本発明の冷却ドラムにおいては、鋼種や、所望の板厚、品質に応じ、上記微小突起及び細孔を、適宜、組合せて、冷却ドラムの周面構造を構成することができるが、最大の特長とするところは、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜を形成することである。
即ち、本発明の冷却ドラムは、“ディンプル割れ”の発生、及び、“酸洗むら”及び“酸洗むら付随割れ”の発生の両方を抑制し、高品質の薄肉鋳片、最終薄板製品を歩留り良く製造するため、ドラムの周面構造及び周面材質の両観点から改善をしたものである。
【0044】
そして、本発明の冷却ドラムは、単ロール式の連続鋳造、及び、双ロール式の連続鋳造のいずれにも使用することができる。
以下、本発明の実施例について説明するが、本発明は、実施例で用いた冷却ドラムの周面構造及び周面材質、及び、連続鋳造条件に限定されるものではない。
【0045】
【実施例】
SUS304系ステンレス鋼を双ドラム式連続鋳造機により、板厚3mmの帯状薄肉鋳片に鋳造し、冷間圧延して板厚0.5mmの薄板製品を製造した。上記鋳片を鋳造するに際し、幅1330mm、直径1200mmの冷却ドラムの外筒部は銅製とし、外筒部の周面には厚み1mmのNiメッキを施した後、表1に示す被覆層を形成した。
【0046】
なお、表1において、窪みは、ショットブラストで加工したものである。
割れ・光沢むらは、薄肉鋳片を冷間圧延及び酸洗焼鈍後に、肉眼観察により判定した。
【0047】
【表1】
【0048】
【発明の効果】
本発明によれば、表面割れ、亀裂等の表面欠陥や、酸洗むらに加え、酸洗むら付随割れのない薄肉鋳片を能率よく製造することができる。
したがって、本発明は、表面性状に優れ、かつ、光沢むらのない高品質のステンレス鋼薄鋼板を、歩留り良く安価に提供することができ、ステンレス鋼を、製品素材や、建材として使用する消費財製造業や、建築業等の発展に大きく寄与するものである。
【図面の簡単な説明】
【図1】連続鋳造した薄肉鋳片の表面に発現した“酸洗むら”と“酸洗むら付随割れ”の態様を示す図である。
【図2】図1に示す“酸洗むら付随割れ”の発生機構を模式的に示す図である。
【図3】“ディンプル深さ”(凝固態様)と、“ディンプル割れ”及び“酸洗むら付随割れ”の“割れ長さ”(発生状況)との関連性を示す図である。
【図4】“ディンプル割れ”の発生機構を模式的に示す図である。
【符号の説明】
1…スカム
2…凝固シェル
3…ディンプル
4…ガスギャップ
5…酸洗むら付随割れ
6…凝固核生成
7…溶鋼の凸部
8…ディンプル割れ
9…溶鋼
10…冷却ドラム
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single-drum continuous casting machine or a twin-drum continuous casting machine that casts a thin-walled slab directly from ordinary steel, stainless steel, alloy steel, silicon steel and other steels, alloys, and molten metal. The present invention relates to the surface structure and surface material of the cooling drum.
[0002]
[Prior art]
Thin-wall casting with a plate thickness of 1 to 10 mm by a twin-drum continuous casting apparatus equipped with a pair of cooling drums (hereinafter also referred to as “drums”) or a single-drum continuous casting apparatus equipped with a single cooling drum. A technique for continuously casting a piece (hereinafter sometimes referred to as “slab”) has been developed.
[0003]
Since this technique produces a thin cast slab having a shape and thickness close to that of the final product, in order to finally obtain a final product with a high yield and a required level of quality, It is essential to obtain a cast slab free from surface defects such as cracks and cracks and uneven pickling.
In particular, since a high quality surface property is required for a stainless steel sheet product, casting a thin slab without uneven pickling becomes a major issue.
[0004]
This surface defect is caused by heat shrinkage stress caused by non-uniform solidification shell formation on the surface of the cooling drum when thin cast slabs are continuously cast. The surface structure of the cooling drum that is known to be formed on the basis of the imbalance and that has cooled and solidified the molten steel so that this heat shrinkage stress imbalance does not remain in the slab as much as possible. Various proposals have been made.
[0005]
For example, in JP-A-4-238651, a recess having a depth of 50 to 200 μm is formed on the peripheral surface at an area ratio of 15 to 30%, and a recess having a depth of 10 to 50 μm is formed to 40 to 60%. A cooling drum for continuous casting formed with an area ratio is disclosed. Japanese Patent Application Laid-Open No. 6-328204 discloses a recess having a diameter of 100 to 300 μm and a depth of 100 to 500 μm formed on the peripheral surface with an area ratio of 15 to 50%, and a diameter of 400 to 1000 μm and a depth of 10 to 100 μm. A cooling drum for continuous casting is disclosed in which a depression having an angle of 45 to 75 ° formed by a line perpendicular to the tangential line of the peripheral surface and a side surface of the depression is formed at an area ratio of 40 to 60%.
[0006]
These cooling drums suppress the occurrence of surface cracks and cracks on the surface of the slab and suppress the occurrence of pickling unevenness, which is another typical surface defect. In producing a thin plate product, there is a remarkable effect.
In JP-A-11-179494, a large number of protrusions (preferably a height of 20 μm or more, a diameter of 0.2 to 1.0 μm, and a closest interval of 0.2 to 1.0 mm) are formed on the peripheral surface. A cooling drum for continuous casting is disclosed. This cooling drum can suppress surface defects to almost none in continuous casting of thin cast slabs.
[0007]
Furthermore, in JP-A-9-103849, a Ni layer and a Co layer having a thickness of 10 to 500 μm are sequentially formed on the peripheral surface, and the sum of the thicknesses of the Ni layer and the Co layer is 500 μm to 2 mm. A cooling drum is disclosed in which depressions with an average depth of 30 to 150 μm are formed on the surface of the Co layer, and Japanese Laid-Open Patent Publication No. 9-103850 discloses a Ni layer formed on the peripheral surface. Disclosed is a cooling drum in which layers are subjected to shot blasting to provide depressions with an average depth of 10 to 50 μm, and then electroplated with a thickness of 10 to 500 μm, so that the average depth of the depressions is 30 to 150 μm. .
[0008]
These cooling drums are designed to suppress cracking in the thin cast slab and extend the life of the drum by improving and devising the peripheral structure and material of the drum. It is.
In this way, in the technology of continuously casting thin cast pieces having a thickness of 1 to 10 mm, surface defects including pickling unevenness are suppressed by improving and devising the peripheral structure and peripheral material of the cooling drum. With great success.
[0009]
However, during operation, even if the hot water reservoir that receives the molten steel formed by the cooling drum and the side weirs abutting on both sides of the cooling drum is surrounded by an inert atmosphere and the generation of scum is suppressed as much as possible, intervening from the inside of the molten steel It is inevitable that a considerable amount of scum floats on the surface of the molten steel and agglomerates due to the floating of objects and mixed slag. And this scum is wound between a cooling drum and molten steel, and pickling unevenness appears on the surface of a thin cast slab.
[0010]
This pickling unevenness part is manifested as gloss unevenness in the final thin plate product and decreases its value as a product material. Therefore, in order to further improve the quality and yield of the final thin plate product, continuous casting of thin slabs In this case, in addition to suppressing the generation of scum as much as possible, even if the scum is caught, the occurrence of pickling unevenness in the thin cast slab can be suppressed as much as possible. Is needed.
[0011]
Therefore, the present inventor investigated in detail the thin-walled slab in which pickling unevenness was developed in order to find out the countermeasure. As a result, the present inventor has discovered that a “crack” having a form different from that of the conventionally known surface crack is generated in the vicinity of the boundary between the region where pickling unevenness appears and the region where the pickling unevenness does not occur. FIG. 1 shows this “crack” (hereinafter referred to as “accompanied crack pickling”).
[0012]
As can be seen from FIG. 1, “accompaniment crack” is a surface crack (hereinafter, sometimes referred to as “dimple crack”) that occurs in a portion where no pickling occurs. It is different in terms of origin, position, form, etc.
Therefore, it is difficult to prevent the above-mentioned extraneous “pickling accompanied by pickling” with the conventional means.
[0013]
Thus, in the continuous casting of thin-walled slabs, in addition to the problem of suppressing the occurrence of "dimple cracking" and "pickling unevenness", the problem of suppressing the occurrence of "pickling uneven cracking" I had a new one.
[0014]
[Problems to be solved by the invention]
Accordingly, the present invention has an object to suppress the occurrence of “dimple cracking” and the occurrence of “pickling unevenness” and “pickling accompanying cracking” in continuous casting of thin-walled slabs. Is to solve the problem from the viewpoint of the peripheral surface structure and peripheral material of the cooling drum that greatly affects the solidification mode of the molten steel.
[0015]
[Means for Solving the Problems]
For pickling, the solidification of the molten steel is delayed at the site where the scum adheres, and as a result, the solidified structure of the scum adhering part becomes different from the solidified structure around the scum. Since it is expressed as “unevenness” on the surface, it is presumed that the solidification mode of the molten steel on the surface of the cooling drum is also greatly involved in the occurrence of “accurate pickling uneven cracking”.
[0016]
Therefore, the present inventor first investigated the solidification mode of the thin-walled slab in which the “acid pickling uneven crack” as shown in FIG. 1 occurred. Due to the inflow and adhesion of scum, the thermal resistance at the interface between the cooling drum and molten steel changes, resulting in a difference in the thickness of the solidified shell formed between the part where the scum is attached and the part where it is not. Thus, specifically, it has been found that the non-uniformity of the solidified shell thickness occurs at a site exceeding 20%.
[0017]
FIG. 2 schematically shows the generation mechanism. In the part where the scum 1 is adhered, the thermal resistance at the interface between the cooling drum 10 and the molten steel 9 changes, and the solidification of the molten steel is delayed. Therefore, the thickness of the solidified shell 2 is thinner than the thickness of the solidified shell in other parts. However, due to the synergistic action of the gas gap 4 formed between the scum 1 and the concave surface of the dimple 3, the boundary between the thick solidified shell and the thin solidified shell (uneven portion of the solidified shell thickness) Distortion "occurs and accumulates. When the non-uniformity of the thickness of the solidified shell exceeds 20%, as shown in FIG.
[0018]
As described above, the occurrence and accumulation of “strain” that causes “accurate pickling crack 5” is also associated with the presence of gas gap 4 formed between scum 1 and the dimple 3 recess. Therefore, the inventor further changed the solidification mode of the molten steel by changing the “depth” of the dimple, and changed the solidification mode (“dimple depth” was used as an index indicating this change). The relationship between the occurrence of “dimple cracking” and “accompanied crack pickling” (“crack length” was used as an index indicating the occurrence) was investigated.
[0019]
The result is shown in FIG. According to this figure, it can be seen that if the depth (μm) of the dimple is reduced, the occurrence of “dimple cracking” can be prevented, but conversely, the occurrence of “accompaniment cracking” is promoted.
As described above, the present inventor found that the occurrence or suppression of occurrence of “pickling accompanying cracks” and “dimple cracks” is a trade-off relationship in terms of the relationship with the depth of the dimples formed on the peripheral surface of the cooling drum. I found out that
[0020]
Here, FIG. 4 schematically shows a generation mechanism of “dimple cracking”. Solidification nuclei are generated in the molten steel portion in contact with the top of the dimple 3 (see “6” in the figure), and solidification proceeds from here, but the convex portion 7 of the molten steel formed by entering the concave portion of the dimple 3 is formed. When solidifying, solidification is non-uniform compared to dimple units, and due to this non-uniformity, non-uniform stress / strain accumulates for each dimple unit. The “dimple crack 8” occurs due to the non-uniform stress / strain.
[0021]
When the convex portion 7 of the molten steel is solidified, the scum becomes a thermal resistance in the portion where the scum 1 is adhered, and naturally solidification is delayed. In this case, the uneven stress and strain are alleviated due to the solidification delay.
The findings obtained from the above survey results are summarized as follows.
(A) Although molten steel contacts the top of the dimple, it does not completely contact the bottom due to the presence of the gas gap.
(B) The molten steel that contacts the top of the dimple solidifies faster than the molten steel that does not contact the top.
(C) When a gas gap exists between the molten steel and the dimple surface, the gas gap acts as a thermal resistance, and solidification of the molten steel is delayed.
(D) If a gas gap exists between the molten steel to which the scum adheres and the dimple surface, the scum and the gas gap act as thermal resistance, and solidification of the molten steel becomes slower. As a result, there is a difference between the thickness of the solidified shell at the site where the scum is attached and the thickness of the solidified shell at the site where the scum is not attached, and uneven stress and strain are accumulated at the thickness boundary portion. This causes “accompaniment cracking”.
(E) If the “dimple depth” is shallow, the intrusion height of the molten steel into the dimple concavity (height of the convex portion) is low, so the accumulation of non-uniform stress and strain for each dimple unit is alleviated, The occurrence of cracking is suppressed, but conversely, the accumulation of non-uniform stress and strain due to solidification delay based on scum and gas gap is promoted, and “pickling accompanying cracking” occurs frequently along with “pickling unevenness”. To do.
(F) If the “dimple depth” is deep, the depth of penetration of the molten steel into the dimple recess (the height of the convex portion) is high, so that accumulation of non-uniform stress and strain for each dimple unit is promoted. ”Occurs frequently, but conversely, the accumulation of non-uniform stress and strain due to solidification delay due to scum and gas gap is alleviated, so the occurrence of“ pickling unevenness ”along with“ pickling unevenness ”is suppressed. Is done.
[0022]
Based on these findings, the present inventor first secures a “dimple depth” that can suppress “dimple cracking” in the dimple form, and on the surface of the dimple on the premise of this “dimple depth”. ,
(X) Do not form a gas gap that becomes thermal resistance,
(Y) delay solidification of the molten steel in contact with the top, and
(Z) Promote solidification of the molten steel in contact with the bottom,
If the function is added, it is possible to reduce the uneven stress and strain accumulated in the thickness boundary part of the solidified shell based on the solidification delay at the scum adhesion site, resulting in the occurrence of “dimple cracking”. Further, the inventors have come up with the idea that both “pickling unevenness” and “accompanied cracking” can be suppressed.
[0023]
Based on the above idea, the present inventor diligently conducted research on the surface that fulfills the function (x) in the dimples formed on the peripheral surface of the cooling drum. As a result, the presence of the gas gap is greatly related to the wettability between the surface of the cooling drum and the scum,
(X) If a substance having good wettability with the scum is present on the surface of the cooling drum, the scum becomes familiar with the surface, and a gas gap is hardly formed.
And gained knowledge.
[0024]
The surface of the cooling drum is usually plated with Ni, but it has been found that a Ni—W alloy is suitable as a substance having good wettability with scum.
Furthermore, the present inventor has similarly conducted intensive research on the surfaces that perform the functions (y) and (z). as a result,
(Y) If the round shape of the predetermined shape is added to the top of the dimple, or the “pore” of the predetermined shape is formed, solidification of the molten steel in contact with the top of the dimple can be delayed.
And gained knowledge.
[0025]
In addition, if the formation of the gas gap is suppressed and the top of the dimple is rounded or the pore is formed, the molten steel can easily hit the bottom of the dimple under the cooling force of the cooling drum. In contact with the generated solidification nuclei to solidify,
(Z) If “microprojections” are formed at the bottom of the dimple, the formation of solidification nuclei is promoted, and solidification of the molten steel proceeds faster.
And gained knowledge.
[0026]
Based on the above knowledge, the present invention further preferably has a dimple shape, a “round” or “pore” shape formed on the top of the dimple, and a “microprotrusion” shape formed on the bottom of the dimple. It was made after confirming the relationship.
And the summary of the invention which concerns on the cooling drum for thin cast slab continuous casting is as follows.
(1) A cooling drum that continuously casts a thin slab, and a recess having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is formed on the plated drum peripheral surface. Formed adjacent to each other through the top The top of the depression has an acute shape And a film containing a substance having better wettability with scum than Ni on the peripheral surface A film with better wettability with scum than Ni A cooling drum for continuous casting of a thin-walled slab characterized in that is formed.
(2) A cooling drum that continuously casts a thin-walled slab, and a recess having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is formed on the plated drum peripheral surface. Formed adjacent to each other through the top The top of the depression has an acute shape In addition, microprojections having a height smaller than the average depth of the recesses and having a height of 1 to 50 μm and a diameter corresponding to a circle of 5 to 200 μm are formed on the surface of the recess. And a film containing a substance having better wettability with scum than Ni on the surface A film with better wettability with scum than Ni A cooling drum for continuous casting of a thin-walled slab characterized in that is formed.
(3) A cooling drum that continuously casts a thin slab, and a recess having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is formed on the plated drum peripheral surface. The projections are formed adjacent to each other through the top, and the microprojections having a height of 1 to 50 μm and a circle equivalent diameter of 30 to 200 μm are formed adjacent to each other on the top of the recess. Further, a coating containing a substance having better wettability with scum than Ni on the peripheral surface A film with better wettability with scum than Ni A cooling drum for continuous casting of a thin-walled slab characterized in that is formed.
(4) A cooling drum for continuously casting a thin cast slab, wherein a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is formed on the drum peripheral surface. The projections are formed adjacent to each other via the tops, and microprojections having a height of 1 to 50 μm and a circle-equivalent diameter of 5 to 200 μm are formed adjacent to each other at the tops of the depressions; and The surface of the depression is formed with a minute protrusion having a height smaller than the average depth of the depression, the height being 1 to 50 μm, and the diameter corresponding to a circle is 5 to 200 μm. A film containing a substance whose wettability with scum is better than Ni on the peripheral surface A film with better wettability with scum than Ni A cooling drum for continuous casting of a thin-walled slab characterized in that is formed.
(5) A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is formed on the plated drum peripheral surface. The pores are formed adjacent to each other via the top, the pores having a depth of 5 to 100 μm and a circle-equivalent diameter of 5 to 200 μm are formed at the top of the recess, and the surface of the recess is formed. , A microprojection having a height smaller than the average depth of the depression, the microprojection having a height of 1 to 50 μm and a circle-equivalent diameter of 5 to 200 μm is formed. Coating containing a material with better wettability than Ni A film with better wettability with scum than Ni A cooling drum for continuous casting of a thin-walled slab characterized in that is formed.
(6) The substance having better wettability with Ni than scum is an oxide of the same element as that constituting the continuously cast molten steel (1), (2), (3 ), (4) or (5).
(7) The substance (1), (2), (3), wherein the material having better wettability with Ni than scum is an oxide of an element constituting plating on the peripheral surface of the cooling drum. A cooling drum for continuous casting of a thin cast slab according to (4) or (5).
(8) A film containing a substance having better wettability with the scum than Ni A film with better wettability with scum than Ni The cooling drum for continuous casting of a thin cast slab according to (1) or (2), wherein the coating is formed by oxidizing the plating on the circumferential surface of the cooling drum.
(9) A film containing a substance whose wettability with the scum is better than Ni A film with better wettability with scum than Ni The thin cast film according to (1) or (2), wherein the coating is formed by adhering an oxide produced by oxidizing a component element in molten steel to the plating on the peripheral surface of the cooling drum A cooling drum for continuous casting.
(10) The above plating (1), (2), (3), (4), (5), (8) or (8), wherein the plating is a plating containing an element that is more easily oxidized than Ni. 9) A cooling drum for continuous casting of thin-walled slabs.
(11) The plating (1), (2), (3), (4), (5), wherein the plating is a plating containing one or more of W, Co, Fe, and Cr. ), (8) or (9).
[0027]
Moreover, the summary of the invention which concerns on the continuous casting method using the cooling drum for thin cast slab continuous casting as described in any one of said (1)-(11) is as follows.
(12) Molten steel is injected onto the peripheral surface of the cooling drum for continuous casting of the thin cast slab according to any one of (1) to (11), which rotates in one direction, and the molten steel is injected into the peripheral surface of the cooling drum. A method for continuously casting thin-walled slabs, comprising cooling and solidifying the slab and continuously casting thin-walled slabs.
(13) A sump portion on a part of the peripheral surface of the cooling drum for continuous casting of a thin cast slab according to any one of (1) to (11), which is arranged in parallel and rotates in opposite directions to each other A method for continuously casting a thin-walled cast slab, characterized in that the molten steel injected into the hot water reservoir is cooled and solidified on the peripheral surface of the cooling drum to continuously cast the thin-walled cast slab.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in further detail.
The cooling drum for continuous casting of the thin cast slab of the present invention (hereinafter referred to as “cooling drum of the present invention”) has an average depth of 40 to 200 μm and a circle equivalent diameter of 0. 5 to 3 mm depressions are formed adjacent to each other through the top of the depressions, and a coating containing a substance having better wettability with Ni than scum is formed on the peripheral surface. The basic technical idea.
[0029]
In accordance with the above knowledge, by forming a coating containing a substance having better wettability with Ni on the drum peripheral surface plated with the peripheral surface of the cooling drum, the peripheral surface and the molten steel are formed on the peripheral surface of the cooling drum. The function which can suppress the production | generation of the gas gap used as thermal resistance between these as much as possible is provided.
When a solidified shell is formed on the peripheral surface of the cooling drum, if there is no s gap, the scum will flow in, and even if the solidification of the molten steel at the part where the scum has adhered is delayed, the molten steel does not have scum attached There is no solidification non-uniformity sufficient to induce “cracking associated with pickling” during the solidification of the steel.
[0030]
Usually, the surface of a cooling drum for continuous casting of thin-walled slabs has a lower thermal conductivity than Cu and is harder and more heat-resistant than that of Cu for slow cooling and longer life (preventing surface cracking due to thermal stress). Ni plating that is strong against stress is applied, and the plating is preferably a plating containing one or more elements of elements that are more easily oxidized than Ni, for example, W, Co, Fe, and Cr.
[0031]
In the cooling drum of the present invention, in order to improve the wettability with the scum while maintaining the slow cooling and long life on the surface of the drum, a material having better wettability with the scum than Ni is provided on the surface. Form a film containing.
Since scum is an aggregate of oxides of elements constituting molten steel, the oxide of elements constituting molten steel that is continuously cast is preferable as the material having better wettability with Ni than scum.
[0032]
The film containing a substance having better wettability with Ni than scum may be a film in which the plating peripheral surface of the cooling drum is coated with an oxide of an element constituting molten steel by means of a spray or a roll coater. Further, it may be a film formed by attaching an oxide generated by oxidizing a component element in molten steel to the plating on the peripheral surface of the cooling drum during operation.
[0033]
Further, the substance having better wettability with Ni than the scum may be an oxide of an element constituting plating on the peripheral surface of the cooling drum. This is because the oxide produced by oxidizing the plating on the peripheral surface of the cooling drum with the heat of the molten steel has better wettability with the scum than the plating.
Therefore, in practice, it is not necessary to form an oxide film of the elements constituting the plating again on the peripheral surface of the cooling drum, and it was formed on the peripheral surface of the cooling drum with the heat of molten steel during operation. The plating oxide can be used as it is.
[0034]
In the cooling drum of the present invention, depressions having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm are adjacent to each other through the top of the depressions on the drum peripheral surface on which plating has been performed. Is formed.
The average depth of the dimples is 40 to 200 μm. If the average depth is less than 40 μm, the effect of mitigating macro stress strain due to dimples cannot be obtained, so the lower limit is set to 40 μm. On the other hand, if the average depth exceeds 200 μm, the penetration of molten steel into the dimple bottom becomes insufficient and the dimple non-uniformity increases, so the upper limit is set to 200 μm.
[0035]
The size of the depression is 0.5 to 3 mm in a circle equivalent diameter. If this diameter is less than 0.5 mm, the penetration of the molten steel into the dimple bottom becomes insufficient and dimple non-uniformity increases, so the lower limit is made 0.5 mm. On the other hand, if the diameter corresponding to the circle exceeds 3 mm, the accumulated amount of stress / strain in the dimple unit increases and dimple cracking is likely to occur, so the upper limit is set to 3 mm. And in the cooling drum of this invention, the hollow of the said shape is formed adjacent to each other via the top part of the hollow.
[0036]
When such a depression is formed, each depression can disperse the stress / strain acting on the solidified shell, and the macro stress / strain acting on the solidified shell can be reduced.
In the cooling drum of the present invention, it is preferable to form minute protrusions having a height of 1 to 50 μm and a circle-equivalent diameter of 5 to 200 μm on the surface of the recess having the above shape. By these minute protrusions, solidification of the molten steel in contact with the surface of the recess can be promoted.
[0037]
If the height is less than 1 μm, the protrusions cannot sufficiently contact the molten steel, solidification nuclei are not generated, and solidification of the molten steel cannot be promoted, so the lower limit is set to 1 μm. On the other hand, if the height exceeds 50 μm, solidification of the molten steel at the bottom of the projection is delayed and non-uniformity of the solidified shell in the recess occurs, so the upper limit is set to 50 μm.
If the diameter corresponding to the circle is less than 5 μm, cooling at the protrusions is insufficient and solidification nuclei are not generated, so the lower limit is set to 5 μm. On the other hand, when the diameter corresponding to the circle exceeds 200 μm, a portion where the molten steel is not sufficiently in contact with the protrusion is generated, and the generation of solidified nuclei becomes nonuniform, so the upper limit is 200 μm.
[0038]
The microprotrusions are formed with a film containing a material having better wettability with scum than Ni.
Further, in the cooling drum of the present invention, the minute protrusions on which the film containing a material having better wettability with the scum than Ni is formed are the minute protrusions to which the oxide generated by oxidizing the component elements in the molten steel is attached. It may be a protrusion. Oxidation generated by oxidation of component elements in molten steel adheres to the microprojections, so that the wettability between the microprojections and the scum is further improved, and more in the molten steel portion in contact with the microprojections. It is possible to accelerate the solidification of molten steel by promoting the generation of solidification nucleation starting points.
[0039]
In the cooling drum of the present invention, a film containing a substance having a height of 1 to 50 μm, a circle-equivalent diameter of 30 to 200 μm, and a wettability with scum better than Ni is formed on the top of the recess having the above shape. It is preferable that the microprotrusions are formed adjacent to each other.
The top of the dimple with the dimples formed has an acute shape, but by forming a large number of the above-mentioned microprotrusions adjacent to each other on the top, it can be rounded. it can. Due to this “roundness”, in the molten steel in contact with the top of the dimple, the formation of solidification nuclei is delayed and the progress of solidification is delayed. Further, the “round” dimple top portion serves to promote the penetration of the molten steel into the concave portion of the dimple. As a result, the molten steel easily comes into contact with the bottom of the dimple under the static pressure of the molten steel or the reduction force of the cooling drum.
[0040]
If the height is less than 1 μm, the effect of delaying solidification nucleation at the top of the dimple cannot be obtained, so the lower limit is 1 μm. On the other hand, if the height exceeds 50 μm, the penetration of the molten steel into the dimple bottom becomes insufficient, so the upper limit is made 50 μm.
If the equivalent circle diameter is less than 30 μm, the effect of delaying solidification nucleation at the top of the dimple cannot be obtained, so the lower limit is set to 30 μm. On the other hand, if the diameter corresponding to the circle exceeds 200 μm, the stress / strain relaxation effect by dimples cannot be obtained, so the upper limit is set to 200 μm.
[0041]
Further, with the dimples being formed, “pores” having a depth of 5 μm or more and a circle-equivalent diameter of 5 to 200 μm are formed on the tops of the dimples having an acute shape instead of the minute projections. It is preferable. Due to the formation of the “pores”, the sharp shape at the top of the dimple disappears and a slow cooling part (air gap) for holding gas is formed. It delays the formation of solidification nuclei in the molten steel in contact with the top and slows the progress of solidification. Further, the dimple top portion having “pores” promotes the penetration of molten steel into the concave portion of the dimple. As a result, the molten steel easily comes into contact with the bottom of the dimple under the static pressure of the molten steel or the reduction force of the cooling drum.
[0042]
If the depth is less than 5 μm, the air gap is not sufficiently formed in the pores, and the effect of delaying solidification nucleation cannot be obtained, so the lower limit is set to 5 μm.
If the equivalent circle diameter is less than 5 μm, solidification nuclei are generated near the top other than the pores, and the effect of promoting the penetration of molten steel into the dimple bottom cannot be obtained, so the lower limit is made 10 μm. On the other hand, if the diameter corresponding to the circle exceeds 200 μm, the height of the top of the dimple is apparently lowered, and a stress / strain relaxation effect cannot be obtained, so the upper limit is set to 200 μm.
[0043]
In the cooling drum of the present invention, depending on the steel type, desired plate thickness, and quality, the microprojections and pores can be combined as appropriate to constitute the peripheral structure of the cooling drum. It is to form a film containing a substance having better wettability with Ni on the peripheral surface than Ni.
In other words, the cooling drum of the present invention suppresses both the occurrence of “dimple cracking” and the occurrence of “pickling unevenness” and “pickling accompanied by pickling unevenness”, and enables the production of high-quality thin cast slabs and final thin plate products. In order to manufacture with a high yield, the drum is improved from both viewpoints of the peripheral structure and peripheral material of the drum.
[0044]
The cooling drum of the present invention can be used for both single roll type continuous casting and twin roll type continuous casting.
Examples of the present invention will be described below, but the present invention is not limited to the peripheral structure and material of the cooling drum used in the examples and the continuous casting conditions.
[0045]
【Example】
SUS304 stainless steel was cast into a strip-shaped thin-walled slab having a thickness of 3 mm by a twin drum type continuous casting machine, and cold-rolled to produce a thin-plate product having a thickness of 0.5 mm. When casting the slab, the outer cylinder part of the cooling drum having a width of 1330 mm and a diameter of 1200 mm is made of copper, and the outer surface of the outer cylinder part is plated with Ni having a thickness of 1 mm, and then the coating layer shown in Table 1 is formed. did.
[0046]
In Table 1, the depressions are those processed by shot blasting.
Cracks and gloss unevenness were determined by visual observation after cold-rolling and pickling annealing of thin-walled slabs.
[0047]
[Table 1]
[0048]
【The invention's effect】
According to the present invention, in addition to surface defects such as surface cracks and cracks and pickling unevenness, it is possible to efficiently produce a thin-walled slab free from pickling uneven cracks.
Therefore, the present invention can provide a high-quality stainless steel sheet with excellent surface properties and no unevenness of gloss at a low yield with good yield, and consumer goods that use stainless steel as a product material or building material. It greatly contributes to the development of manufacturing industry and construction industry.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing aspects of “pickling unevenness” and “pickling accompanied by pickling unevenness” developed on the surface of a continuously cast thin slab.
FIG. 2 is a diagram schematically showing a mechanism of occurrence of “accompaniment cracking accompanied by pickling” shown in FIG. 1;
FIG. 3 is a diagram showing the relationship between “dimple depth” (solidification mode) and “crack length” (occurrence state) of “dimple crack” and “crack accompanying crack”.
FIG. 4 is a diagram schematically showing a generation mechanism of “dimple cracking”.
[Explanation of symbols]
1 ... Scum
2 ... Solidified shell
3 ... Dimple
4 ... Gas gap
5 ... Cracking accompanying pickling
6 ... Solidification nucleation
7 ... Projection of molten steel
8 ... Dimple crack
9 ... Molten steel
10 ... Cooling drum

Claims (13)

薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されて窪みの頂部は鋭角的な形状をなしているとともに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is provided on the plated drum peripheral surface through the top of the depression. The tops of the recesses formed adjacent to each other have an acute angle shape , and the peripheral surface is a film containing a substance having better wettability with Ni than scum, and is wet with scum. A cooling drum for continuous casting of a thin cast slab characterized in that a film having better properties than Ni is formed. 薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されて窪みの頂部は鋭角的な形状をなしているとともに、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該表面には、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is provided on the plated drum peripheral surface through the top of the depression. The tops of the recesses formed adjacent to each other have an acute shape, and are formed on the surface of the recesses with microprojections having a height smaller than the average depth of the recesses, the height being 1 to 1. A microprotrusion having a diameter of 50 μm and a circle equivalent diameter of 5 to 200 μm is formed. Further, the surface is a film containing a substance having better wettability with Ni than scum, and the wettability with the scum is A cooling drum for continuous casting of a thin cast slab, wherein a coating better than Ni is formed. 薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、高さが1〜50μm、円相当の径が5〜200μmの微小突起が、相互に隣接して形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is provided on the plated drum peripheral surface through the top of the depression. Are formed adjacent to each other, and microprojections having a height of 1 to 50 μm and a diameter corresponding to a circle of 5 to 200 μm are formed adjacent to each other at the top of the recess, For thin-walled slab continuous casting, characterized in that a film containing a material having better wettability with Ni than scum and having better wettability with Ni is formed on the peripheral surface. Cooling drum. 薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、高さが1〜50μm、円相当の径が30〜200μmの微小突起が相互に隣接して形成され、かつ、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is provided on the plated drum peripheral surface through the top of the depression. Are formed adjacent to each other, and minute projections having a height of 1 to 50 μm and a diameter corresponding to a circle of 30 to 200 μm are formed adjacent to each other at the top of the recess, On the surface, a microprojection having a height smaller than the average depth of the depression, the microprojection having a height of 1 to 50 μm and a diameter corresponding to a circle of 5 to 200 μm is formed, and on the peripheral surface, A cooling drum for continuous casting of a thin-walled slab, characterized in that a film containing a substance having better wettability with Ni than scum and having better wettability with Ni than scum is formed. 薄肉鋳片を連続鋳造する冷却ドラムであって、メッキが施されたドラム周面に、平均深さが40〜200μm、円相当の径が0.5〜3mmの窪みが、窪みの頂部を介して相互に隣接して形成されているとともに、該窪みの頂部に、深さが5〜100μm、円相当の径が5〜200μmの細孔が形成され、かつ、該窪みの表面に、窪みの平均深さよりも小さい高さの微小突起であって、高さが1〜50μm、円相当の径が5〜200μmの微小突起が形成されていて、さらに、該周面に、スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が形成されていることを特徴とする薄肉鋳片連続鋳造用冷却ドラム。A cooling drum that continuously casts a thin-walled slab, and a depression having an average depth of 40 to 200 μm and a circle-equivalent diameter of 0.5 to 3 mm is provided on the plated drum peripheral surface through the top of the depression. Are formed adjacent to each other, and a pore having a depth of 5 to 100 μm and a circle-equivalent diameter of 5 to 200 μm is formed at the top of the recess, and a recess is formed on the surface of the recess. A microprojection having a height smaller than the average depth and having a height of 1 to 50 μm and a circle-equivalent diameter of 5 to 200 μm is formed, and the wettability with the scum is further formed on the peripheral surface. A cooling drum for continuous casting of a thin cast slab characterized in that is a coating containing a material better than Ni, and a coating better in wettability with Ni than scum is formed. 前記スカムとの濡れ性がNiよりも良い物質が、連続鋳造される溶鋼を構成する元素と同一の元素の酸化物であることを特徴とする請求項1、2、3、4または5記載の薄肉鋳片連続鋳造用冷却ドラム。  The material having better wettability with Ni than the scum is an oxide of the same element as the element constituting the continuously cast molten steel. Cooling drum for continuous casting of thin slabs. 前記スカムとの濡れ性がNiよりも良い物質が、冷却ドラム周面上のメッキを構成する元素の酸化物であることを特徴とする請求項1、2、3、4または5記載の薄肉鋳片連続鋳造用冷却ドラム。  6. The thin cast metal according to claim 1, wherein the material having better wettability with Ni than scum is an oxide of an element constituting plating on a peripheral surface of a cooling drum. A cooling drum for continuous casting. 前記スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が、冷却ドラム周面上のメッキが酸化して形成された皮膜であることを特徴とする請求項1または2記載の薄肉鋳片連続鋳造用冷却ドラム。The film contains a substance having better wettability with Ni than scum, and the film with better wettability with Ni than scum is a film formed by oxidizing the plating on the peripheral surface of the cooling drum. The cooling drum for continuous casting of a thin cast slab according to claim 1 or 2. 前記スカムとの濡れ性がNiよりも良い物質を含む皮膜であって、スカムとの濡れ性がNiよりも良い皮膜が、冷却ドラム周面上のメッキに、溶鋼中の成分元素が酸化して生成した酸化物が付着して形成された皮膜であることを特徴とする請求項1または2記載の薄肉鋳片連続鋳造用冷却ドラム。A film containing a material with better wettability with Ni than scum, and a film with better wettability with Ni than scum is oxidized on the plating on the peripheral surface of the cooling drum by the component elements in the molten steel. The cooling drum for continuous casting of a thin cast slab according to claim 1 or 2, wherein the formed oxide is a film formed by adhering to the oxide. 前記メッキが、Niよりも酸化され易い元素を含むメッキであることを特徴とする請求項1、2、3、4、5、8または9記載の薄肉鋳片連続鋳造用冷却ドラム。  10. The cooling drum for continuous casting of a thin cast slab according to claim 1, wherein the plating is a plating containing an element that is more easily oxidized than Ni. 前記メッキが、W、Co、Fe、Crの1種または2種以上を含むメッキであることを特徴とする請求項1、2、3、4、5、8または9記載の薄肉鋳片連続鋳造用冷却ドラム。  The thin-walled slab continuous casting according to claim 1, 2, 3, 4, 5, 8 or 9, wherein the plating is a plating containing one or more of W, Co, Fe, and Cr. Cooling drum. 一方向に回転する、請求項1〜11のいずれか1項に記載の薄肉鋳片連続鋳造用冷却ドラムの周面上に溶鋼を注入し、該溶鋼を該冷却ドラムの周面上で冷却、凝固させ、薄肉鋳片を連続鋳造することを特徴とする薄肉鋳片の連続鋳造方法。  The molten steel is injected onto the peripheral surface of the thin cast slab continuous casting cooling drum according to any one of claims 1 to 11, which rotates in one direction, and the molten steel is cooled on the peripheral surface of the cooling drum. A method for continuously casting a thin-walled slab comprising solidifying and continuously casting a thin-walled slab. 平行に配置され互いに逆方向に回転する一対の、請求項1〜11のいずれか1項に記載の薄肉鋳片連続鋳造用冷却ドラムの周面の一部に湯溜り部を形成し、該湯溜り部に注入した溶鋼を、該冷却ドラムの周面上で冷却、凝固させ、薄肉鋳片を連続鋳造することを特徴とする薄肉鋳片の連続鋳造方法。  A hot water reservoir is formed on a part of the peripheral surface of the cooling drum for continuous casting of a thin cast slab according to any one of claims 1 to 11, which is arranged in parallel and rotates in opposite directions. A method for continuously casting a thin-walled cast slab, characterized in that the molten steel injected into the reservoir is cooled and solidified on the peripheral surface of the cooling drum, and the thin-walled cast slab is continuously cast.
JP2000306764A 2000-10-05 2000-10-05 Cooling drum for continuous casting of thin-walled slab and continuous casting method of thin-walled slab Expired - Lifetime JP3908902B2 (en)

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JP2000306764A JP3908902B2 (en) 2000-10-05 2000-10-05 Cooling drum for continuous casting of thin-walled slab and continuous casting method of thin-walled slab
PCT/JP2001/003965 WO2001085369A1 (en) 2000-05-12 2001-05-11 Cooling drum for continuously casting thin cast piece and fabricating method and device therefor and thin cast piece and continuous casting method therefor
AT05006812T AT375833T (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR THE CONTINUOUS CONTINUOUS CASTING OF THIN PRODUCTS AND CONTINUOUS CASTING METHOD
AU56712/01A AU777752B2 (en) 2000-05-12 2001-05-11 Cooling drum for continuously casting thin cast piece and fabricating method and device therefor and thin cast piece and continuous casting method therefor
DE60140321T DE60140321D1 (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR CONTINUOUS CASTING OF THIN PRODUCTS
KR1020057016119A KR100668126B1 (en) 2000-05-12 2001-05-11 Apparatus for processing cooling drum for continuously casting thin cast piece
EP01930090A EP1281458B1 (en) 2000-05-12 2001-05-11 Cooling drum for continuously casting thin cast piece and continuous casting method therefor
ES05006811T ES2333232T3 (en) 2000-05-12 2001-05-11 A COOLING DRUM FOR CONTINUOUS COLADA OF THICK IRON.
KR1020027000450A KR100668123B1 (en) 2000-05-12 2001-05-11 Cooling drum for continuously casting thin cast piece and fabricating method and device therefor and thin cast piece and continuous casting method therefor
EP05006813A EP1595622A1 (en) 2000-05-12 2001-05-11 A method of processing a cooling drum for metal cast strip by continuous casting and an apparatus therefor
ES01930090T ES2287125T3 (en) 2000-05-12 2001-05-11 COOLING DRUM FOR CONTINUOUS COLADA OF MOLDED THIN PIECES AND CONTINUOUS COLADA PROCEDURE FOR THE SAME.
AT01930090T AT361167T (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR THE CONTINUOUS CONTINUOUS CASTING OF THIN PRODUCTS AND CONTINUOUS CASTING METHOD
EP05006812A EP1602424B2 (en) 2000-05-12 2001-05-11 A cooling drum for thin slab continuous casting and continuous casting method thereof
ES05006812T ES2291995T5 (en) 2000-05-12 2001-05-11 A cooling drum for continuous thin plate casting and a continuous casting method with it
DE60131034T DE60131034T3 (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR THE CONTINUOUS CONTINUOUS CASTING OF THIN PRODUCTS AND CONTINUOUS CASTING METHOD
AT05006811T AT446814T (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR CONTINUOUS CASTING OF THIN PRODUCTS
EP05006811A EP1595621B1 (en) 2000-05-12 2001-05-11 A cooling drum for thin slab continuous casting
DE60128217T DE60128217T2 (en) 2000-05-12 2001-05-11 COOLED CASTING ROLL FOR THE CONTINUOUS CONTINUOUS CASTING OF THIN PRODUCTS AND CONTINUOUS CASTING METHOD
US10/031,349 US6896033B2 (en) 2000-05-12 2001-05-11 Cooling drum for continuously casting thin cast piece and fabricating method and device therefor and thin cast piece and continuous casting method therefor
EP05006814A EP1582279A1 (en) 2000-05-12 2001-05-11 A continuous cast thin slab
CA002377876A CA2377876C (en) 2000-05-12 2001-05-11 Cooling drum for thin slab continuous casting, processing method and apparatus thereof, and thin slab and continuous casting method thereof
KR1020057016118A KR100692499B1 (en) 2000-05-12 2001-05-11 Method of processing cooling drum for continuously casting thin cast piece
US11/044,561 US7159641B2 (en) 2000-05-12 2005-01-26 Cooling drum for thin slab continuous casting, processing method and apparatus thereof, and thin slab and continuous casting method thereof

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