JP3747007B2

JP3747007B2 - Twin drum type continuous casting method and apparatus

Info

Publication number: JP3747007B2
Application number: JP2002106612A
Authority: JP
Inventors: 友英竹内; 衛山田; 剛多名賀; 俊二庄田; 忠浩伊豆; 英明小林
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2002-04-09
Filing date: 2002-04-09
Publication date: 2006-02-22
Anticipated expiration: 2022-04-09
Also published as: JP2003305547A

Description

【０００１】
【発明の属する技術分野】
本発明は、双ドラム式連続鋳造装置を用いて製造した薄帯鋳片の幅端部に発生するバリ又は及び溶鋼しみ出しを防止する方法及び装置に関するものである。
【０００２】
【従来の技術】
双ドラム式連続鋳造装置を用いた薄帯鋳片の製造方法においては、一対のドラムの両端面に耐火物を内張りした一対のサイド堰を押し付けて湯溜まり部を形成し、湯溜まり部に溶鋼を連続的に供給しながら一対のドラムを回転させ、ドラム周面で生成した一対の凝固シェルをドラム最小ギャップ部（ドラムキス点）で圧着して薄帯鋳片とする。
【０００３】
双ドラム式連続鋳造装置を用いた薄帯鋳片の製造方法においては、消耗品コストの削減及び長時間鋳造による生産能率の向上を図ることが重要であるが、従来においては、サイド堰耐火物の損耗が大きいため、サイド堰耐火物の寿命が消耗品コスト及び鋳造可能時間を左右する大きな要因であった。
【０００４】
サイド堰耐火物の寿命延長を図る方法として、サイド堰を上方シフトさせる方法が知られているが、この場合、サイド堰の上方シフトによりサイド堰下端がシェル未圧着位置まで上昇した時点で溶鋼洩れが発生することになり、サイド堰の上昇可能なストロークは僅かなものとなる。
【０００５】
サイド堰の上昇可能なストロークを拡大させる方法が、例えば特開２００１−８７８４２号公報により知られている。この方法は、サイド堰下端面を傾斜面で形成し、傾斜面の上縁をドラム端面の適正レベルに位置させた状態で鋳造を開始するとともに、サイド堰を耐火物の磨耗速度に応じた速度で上方シフトさせる。すると、傾斜面の上縁は耐火物の磨耗に伴って下方にシフトするため、サイド堰を上方シフトさせても傾斜面の上縁（以下、サイド堰下端という）は適正レベルを維持する。
【０００６】
しかしながら、サイド堰下端の適正位置は、ドラムキス点近傍における溶鋼の凝固状態やドラムの熱膨張の変化等により変化して一定ではないから、サイド堰下端は適正位置に対して下方に位置したり、上方に位置したりすることになる。また、サイド堰の摩耗速度も一定ではないから、サイド堰の磨耗速度が上昇速度に対して大きい場合は、サイド堰下端は適正位置に対して下方に位置することになり、逆に、サイド堰の磨耗速度が上昇速度に対して小さい場合は、サイド堰下端は適正位置に対して上方に位置することになる。
【０００７】
サイド堰下端が適正位置に対して下方に位置した場合は、サイド堰下端が外側に張り出そうとする鋳片端面に押されて押し広げられ、そこに溶鋼が差し込んで強固なバリが生成し、バリがドラムに連れ廻されて鋳片端部が欠損したり、鋳造が不能になる場合がある。逆に、サイド堰下端が適正位置に対して上方に位置すると、サイド堰下端とドラムキス点の間から溶鋼がしみ出して鋳片の端部形状を損なうとともに、しみ出し部位に耳割れが発生する。
【０００８】
【発明が解決しようとする課題】
本発明は、サイド堰下端が適正位置に対して下方に位置した場合の、鋳片両端部のバリ生成を防止し、また、サイド堰下端が適正位置に対して上方に位置した場合の、サイド堰下端からの溶鋼しみ出しを防止することを課題とする。
【０００９】
【課題を解決するための手段】
前記課題を解決する本発明の要旨は以下のとおりである。
（１）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する方法において、前記ドラムの間隙から排出される薄帯鋳片のバリ発生を検出し、バリ発生時は前記サイド堰の押付け速度を下げるか、又は／及び上昇速度を上げることを特徴とする双ドラム式連続鋳造方法。
（２）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する方法において、前記ドラムの間隙から排出される薄帯鋳片の溶鋼しみ出しを検出し、溶鋼しみ出し時は前記サイド堰の押付け速度を上げるか、又は／及び上昇速度を下げることを特徴とする双ドラム式連続鋳造方法。
（３）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する方法において、前記ドラムの間隙から排出される薄帯鋳片のバリ発生と溶鋼しみ出しを検出し、バリ発生時は前記サイド堰の押付け速度を下げるか、又は／及び上昇速度を上げ、溶鋼しみ出し時は前記サイド堰の押付け速度を上げるか、又は／及び上昇速度を下げることを特徴とする双ドラム式連続鋳造方法。
（４）前記ドラムの間隙から排出される薄帯鋳片の幅端部の板厚により、バリ発生を検出することを特徴とする前記（１）又は（３）に記載の双ドラム式連続鋳造方法。
（５）前記ドラムの間隙から排出される薄帯鋳片の板幅又は／及び薄帯鋳片の幅端部の温度により、溶鋼しみ出しを検出することを特徴とする前記（２）又は（３）に記載の双ドラム式連続鋳造方法。
（６）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する装置において、前記サイド堰の押付装置及び昇降装置と、前記ドラムの間隙から排出される薄帯鋳片のバリ発生を検出するバリ検出器と、該バリ検出器からの信号により、前記押付装置によるサイド堰の押付け速度又は／及び前記昇降装置によるサイド堰の上昇速度を制御する制御装置を設けたことを特徴とする双ドラム式連続鋳造装置。
（７）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する装置において、前記サイド堰の押付装置及び昇降装置と、前記ドラムの間隙から排出される薄帯鋳片の溶鋼しみ出しを検出する溶鋼しみ出し検出器と、該溶鋼しみ出し検出器からの信号により、前記押付装置によるサイド堰の押付け速度又は／及び前記昇降装置によるサイド堰の上昇速度を制御する制御装置を設けたことを特徴とする双ドラム式連続鋳造装置。
（８）一対のドラムの両端面に、下端面を傾斜面で形成した一対のサイド堰を押し付けると共に上方シフトさせながら薄帯鋳片を鋳造する装置において、前記サイド堰の押付装置及び昇降装置と、前記ドラムの間隙から排出される薄帯鋳片のバリ発生を検出するバリ検出器と、前記ドラムの間隙から排出される薄帯鋳片の溶鋼しみ出しを検出する溶鋼しみ出し検出器と、前記バリ検出器又は及び溶鋼しみ出し検出器からの信号により、前記押付装置によるサイド堰の押付け速度又は／及び前記昇降装置によるサイド堰の上昇速度を制御する制御装置を設けたことを特徴とする双ドラム式連続鋳造装置。
（９）前記バリ検出器がドラムの間隙から排出される薄帯鋳片の幅端部の板厚を測定する板厚計であることを特徴とする前記（６）又は（８）に記載の双ドラム式連続鋳造装置。
（１０）前記溶鋼しみ出し検出器がドラムの間隙から排出される薄帯鋳片の板幅を測定する板幅計であることを特徴とする前記（７）又は（８）に記載の双ドラム式連続鋳造装置。
（１１）前記溶鋼しみ出し検出器がドラムの間隙から排出される薄帯鋳片の幅端部の温度を測定する温度計であることを特徴とする前記（７）又は（８）に記載の双ドラム式連続鋳造装置。
【００１０】
【発明の実施の形態】
図１は、本発明の実施の形態を説明する図であり、一対のドラム１、１は、互いに反対方向に回転し、ドラムの両端面には一対のサイド堰２が押付けられている。ドラム端面１ａの外周部には、サイド堰２とのシール面圧（押付け面圧）を確保する目的で、図５に示す幅ｗが５〜２０ｍｍ程度のリング状で突出したドラムシール部１ｂが設けられている。３は一対のドラム１、１の間隙から排出された薄帯鋳片Ｓを圧延する圧延機である。
【００１１】
４は、バリ検出器としての板厚計であり、バリは、図７（ａ）に示す断面図のように、鋳片幅端部が上下に張り出しているので鋳片端部の板厚を測定することにより検出することができる。５は、第１の溶鋼しみ出し検出器としての板幅計５であり、溶鋼しみ出し部は、図７（ｂ）に示す断面図のよう、横（外側）に張り出しているので鋳片幅が広くなる。そのため、溶鋼しみ出し部は、通常（正常）の鋳片端部や鋳片幅を測定することにより検出することができる。また、溶鋼しみ出し部はバリ発生部と比べて高温であるから、鋳片端部の温度あるいは輝度や色を測定することによっても検出することができる。そのため、第２の溶鋼しみ出し検出器には温度計６が用いられている。
【００１２】
なお、第１の溶鋼しみ出し検出器５及び第２の溶鋼しみ出し検出器６は、一方のみを設置してもよく、また、設置位置も圧延機３やピンチロール等（図示せず）の後方でもよい。一方、バリ検出器４は鋳片幅端部の上下方向の張り出し部を検出するので、設置位置は張り出し部が圧延などで押し潰されない圧延機３やピンチロール等の前方がよい。７は板厚計４又は板幅計５又は及び温度計６からの信号により、サイド堰２の押付け速度又は／及びサイド堰２の上昇速度を制御する制御装置である。
【００１３】
図２は、サイド堰２の下部側面を拡大して示す断面図であり、金属ケース８内に不定形耐火物９が充填され、不定形耐火物９に耐火煉瓦１０が埋設されている。耐火煉瓦１０のドラムシール部１ｂ（図４参照）と対面する部位に溝（図示せず）が設けられ、溝にＢＮ等のセラミックス板が耐火煉瓦１０から突出して装着されることで略Ｖ字状の突起部１１が形成されている（図５，６参照）。突起部１１の下端には下端傾斜面１１ａが形成されており、図５に示すように、突起部１１の外縁部には外側傾斜面１１ｂが形成されている。
【００１４】
図３は、サイド堰の押付装置及び昇降装置を示す側面図であり、金属ケース８の背面側には、サイド堰２の熱変形を防止する補剛体１２が固定されている。補剛体１２の中央部は、昇降式の支持フレーム１３に固定支持された支持軸１４によって支持されており、補剛体１２の上部２点及び下部１点は、支持フレーム１３に固定支持された油圧又は電動駆動の押付装置１５によって支持されている。
【００１５】
支持フレーム１３は、下部を垂直ガイド１６に案内されて垂直ガイド１６の底面に固定された油圧又は電動駆動の昇降装置１７に連結されている。したがって、サイド堰２は押付装置１５によって一対のドラム１、１の端面１ａに押圧され、昇降装置１７によってドラム端面１ａに沿って昇降移動が可能なように構成されている。
【００１６】
次に、本発明の双ドラム式連続鋳造装置による薄帯鋳片の鋳造方法について説明する。図２において、摩耗前の突起部１１は鎖線で示す厚みであり、鋳造開始時は下端傾斜面の上端１１ｃを例えばドラムキス点ｋｐから上方１０〜２０ｍｍの範囲に位置させる。また、図５において、摩耗前の突起部１１は鎖線で示す厚みであり、図２に示すように、下端傾斜面の上端１１ｃを上記位置に合致させたとき、図５において、外側傾斜面の側縁１１ｄとドラムシール部の内周縁１ｃが合致する。
【００１７】
この状態で図１に示すサイド堰２をドラム端面１ａに押し付けて湯溜まり部Ｐ内に溶鋼Ｙを連続供給し、一対のドラム１、１の周面で凝固シェルを生成させ、ドラム１、１を矢印方向へ回転させて一対の凝固シェル同士をドラムキス点ｋｐで圧着させ、薄帯鋳片ｓを鋳造する。
【００１８】
鋳造中は押付装置１５（図３）を操作して、サイド堰２をドラム端面１ａに例えば１．０μｍ／秒の速度で押付け、また、昇降装置１７（図３）を操作して、サイド堰２を突起部１１の摩耗速度に応じた速度で、例えば０．１５ｍｍ／分で連続的あるいは間欠的に上方シフトさせることで、図２に示す下端傾斜面の上端１１ｃを適正位置に制御してバリ及び溶鋼しみ出しを防止する。
【００１９】
しかしながら、バリ及び溶鋼しみ出しが発生しない範囲は非常に狭く、サイド堰下端が適正範囲に対して僅かでも下方に位置した場合は、前記のようにドラム端面とサイド堰間に溶鋼が差し込んで強固なバリが生成し、逆に、サイド堰下端が適正位置に対して僅かでも上方に位置した場合は、サイド堰下端とドラムキス点の間から溶鋼のしみ出しが発生する。
【００２０】
バリ発生部は、図７（ａ）のように、鋳片幅端部が上方又は及び下方に片側２ｍｍ程度張り出しているので、板厚計４により鋳片幅端部の板厚を測定することにより検出する。また、溶鋼しみ出しが発生すると、鋳片の板幅が５ｍｍ程度拡大するから、板幅計５により鋳片の板幅を測定することによって溶鋼しみ出しを検出する。また、溶鋼しみ出し部はバリ発生部と比べて１００℃程度高温であるから、温度計６により鋳片端部の温度あるいは輝度や色を測定することによっても溶鋼しみ出しを検出する。
【００２１】
制御装置７は板厚計４、板幅計５及び温度計６の信号を連続的に取り込んで設定値と比較例し、バリ発生であると判別すると、押付装置１５によりサイド堰２の押付け速度を、例えば１．０μｍ／秒から０．５μｍ／秒に下げるか、又は／及び昇降装置１７により、サイド堰２の上昇速度を、例えば０．１５ｍｍ／分から０．２０ｍｍ／分に上げる。サイド堰２の押付け速度を下げると、サイド堰の上方シフト量に対してサイド堰耐火物の摩耗速度が小さくなるので、サイド堰下端は上方にシフトして適正位置となり、バリ発生を防止できる。一方、サイド堰２の押付け速度を上げると、サイド堰の上方シフト量に対してサイド堰耐火物の摩耗速度が大きくなるので、サイド堰下端は下方にシフトして適正位置となり、バリ発生を防止できる。
【００２２】
一方、制御装置７が溶鋼しみ出しであると判別すると、制御装置７は押付装置１５により押付け速度を、例えば１．０μｍ／秒から１．５μｍ／秒に上げるか、又は／及び昇降装置１７によりサイド堰２の上昇速度を、例えば０．１５ｍｍ／分から０．１０ｍｍ／分に下げる。サイド堰２の押付け速度を上げると、サイド堰の上方シフト量に対してサイド堰耐火物の摩耗速度が大きくなるので、サイド堰下端は下方にシフトして適正位置となり溶鋼しみ出しを防止できる。一方、サイド堰２の押付け速度を下げると、サイド堰の上方シフト量に対してサイド堰耐火物の摩耗速度が小さくなるので、サイド堰下端は上方にシフトして適正位置となり溶鋼しみ出しを防止できる。
【００２３】
なお、以上の説明では、溶鋼しみ出し検出器として、板幅計５と温度計６の両方を設けたが、一方のみを設けてもよい。また、以上の説明では、バリ発生と溶鋼しみ出しの両方を防止する方法（請求項３）及び装置（請求項８）の例を挙げたが、バリ発生のみを防止する方法（請求項１）又は装置（請求項６）であってもよく、また、溶鋼しみ出しのみを防止する方法（請求項２）又は装置（請求項７）であってもよい。
【００２４】
【発明の効果】
本発明によれば、双ドラム式連続鋳造において、サイド堰を磨耗速度に応じた速度で上方シフトすることにより、サイド堰耐火物の寿命延長を図る方法において、サイド堰下端が適正位置より下方に位置した場合の、鋳片両端部のバリ生成を防止し、また、サイド堰下端が適正位置より上方に位置した場合の、サイド堰下端からの溶鋼しみ出しを防止することができる。その結果、３．５時間（３６０ｔｏｎ）の連続鋳造が可能となり、コストの削減及び長時間鋳造による生産能率の向上を達成しながら品質良好な鋳片を安定して製造することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態を説明する双ドラム式連続鋳造装置の全体図。
【図２】サイド堰下部の側断面図。
【図３】サイド堰の昇降装置及び押付装置の側面図。
【図４】図３のＩ−Ｉ線矢視の正面図である。
【図５】図４のII−II線矢視の部分平断面である。
【図６】図４のIII−III線矢視の平断面である。
【図７】薄帯鋳片端部の断面図であり、（ａ）はバリの断面図、（ｂ）は溶鋼しみ出し部の断面図である。
【符号の説明】
１…ドラム
１ａ…ドラム端面
１ｂ…ドラムシール部
１ｃ…ドラムシール部の内周縁
２…サイド堰
３…圧延機
４…板厚計（バリ検出器）
５…板幅計（第１の溶鋼しみ出し検出器）
６…温度計（第２の溶鋼しみ出し検出器）
７…制御装置
８…金属ケース
９…不定型耐火物
１０…耐火煉瓦
１１…略Ｖ字状の突起部
１１ａ…突起部の下端傾斜面
１１ｂ…突起部の外側傾斜面
１１ｃ…下端傾斜面の上端
１１ｄ…外側傾斜面の側縁
１２…補剛体
１３…昇降式の支持フレーム
１４…支持軸
１５…押付装置
１６…垂直ガイド
１７…昇降装置
Ｓ…薄帯鋳片
ｋｐ…ドラムキス点
Ｙ…溶鋼
Ｐ…湯溜まり部
ｇ…凝固シェル
Ｂ…バリ
Ｃ…溶鋼しみ出し部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for preventing burrs and / or molten steel oozing generated at a width end portion of a strip cast piece manufactured using a twin drum type continuous casting apparatus.
[0002]
[Prior art]
In the method for producing a strip cast using a twin drum type continuous casting apparatus, a pair of side dams lined with refractory is pressed against both end surfaces of a pair of drums to form a pool, and molten steel is formed in the pool The pair of drums are rotated while continuously supplying the material, and the pair of solidified shells generated on the peripheral surface of the drum are pressure-bonded at the drum minimum gap portion (drum kiss point) to form a strip slab.
[0003]
It is important to reduce the cost of consumables and improve the production efficiency by casting for a long time in the manufacturing method of thin strip slabs using twin drum type continuous casting equipment. Therefore, the life of the side dam refractories was a major factor that affected consumables costs and casting time.
[0004]
As a method of extending the life of the side dam refractories, a method of shifting the side dam upward is known. In this case, however, when the lower end of the side dam rises to the shell non-crimping position due to the upper shift of the side dam, molten steel leaks. As a result, the stroke that the side weir can rise becomes slight.
[0005]
For example, Japanese Patent Laid-Open No. 2001-87842 discloses a method for expanding the stroke by which the side weir can be raised. In this method, the lower end surface of the side weir is formed as an inclined surface, casting is started with the upper edge of the inclined surface being positioned at an appropriate level of the end surface of the drum, and the side weir is moved at a speed corresponding to the wear speed of the refractory. Shift up. Then, since the upper edge of the inclined surface shifts downward as the refractory wears, the upper edge of the inclined surface (hereinafter referred to as the side weir lower end) maintains an appropriate level even if the side weir is shifted upward.
[0006]
However, the appropriate position of the lower end of the side weir is not constant due to changes in the solidified state of the molten steel in the vicinity of the drum kiss point, changes in the thermal expansion of the drum, etc. It will be located above. Also, since the side dam wear rate is not constant, if the side dam wear rate is larger than the ascending rate, the side dam lower end will be located below the proper position, and conversely When the wear speed is lower than the rising speed, the lower end of the side weir is positioned above the appropriate position.
[0007]
When the lower end of the side weir is located below the proper position, the lower end of the side weir is pushed and spread by the end face of the slab that is about to protrude outward, and molten steel is inserted there to produce a strong burr. In some cases, the burr is rotated around the drum and the end portion of the slab is lost or casting becomes impossible. Conversely, if the lower end of the side weir is positioned above the appropriate position, the molten steel oozes out between the side dam lower end and the drum kiss point, impairing the shape of the end of the slab and causing cracks at the oozing site. .
[0008]
[Problems to be solved by the invention]
The present invention prevents the generation of burrs at both ends of the slab when the side dam lower end is positioned below the appropriate position, and the side dam when the side dam lower end is positioned above the appropriate position. An object is to prevent molten steel from seeping out from the lower end of the weir.
[0009]
[Means for Solving the Problems]
The gist of the present invention for solving the above problems is as follows.
(1) In a method of casting a strip cast while pressing a pair of side weirs having lower end surfaces formed with inclined surfaces against both end surfaces of a pair of drums and shifting upward, the strips discharged from the gap between the drums A twin-drum continuous casting method characterized by detecting the occurrence of burrs in a slab and decreasing the pressing speed of the side weirs and / or increasing the rising speed when burrs are generated.
(2) In a method of casting a strip cast while pressing a pair of side weirs having lower end surfaces formed with inclined surfaces against both end surfaces of a pair of drums and shifting upward, the strip discharged from the gap between the drums A twin-drum continuous casting method characterized by detecting molten steel seepage of a slab and increasing the pressing speed of the side weir or / and decreasing the ascent speed when the molten steel seeps.
(3) In a method of casting a ribbon cast piece while pressing a pair of side weirs each having a lower end surface having an inclined surface against both end faces of a pair of drums and shifting upward, the ribbon discharged from the gap between the drums Detecting burr generation and molten steel seepage of slab, lowering the side weir pressing speed when burr is generated or / and increasing the rising speed, and increasing the side weir pressing speed when the molten steel seeps, Alternatively, a twin-drum type continuous casting method characterized by lowering the rising speed.
(4) Burr generation is detected by the plate thickness of the width end portion of the strip cast discharged from the gap between the drums. The twin-drum continuous casting according to (1) or (3), Method.
(5) The molten steel exudation is detected based on the sheet width of the strip slab discharged from the gap between the drums and / or the temperature of the width end portion of the strip slab. 3. A twin-drum continuous casting method as described in 3).
(6) In an apparatus for casting a strip cast piece while pressing a pair of side weirs each having a lower end surface formed of an inclined surface against both end surfaces of a pair of drums and shifting upward, a pressing device for the side weir and a lifting device; A burr detector for detecting the occurrence of burrs in the strip cast discharged from the gap between the drums, and the side dam pressing speed by the pressing device or / and the side by the lifting device according to a signal from the burr detector A twin-drum type continuous casting apparatus provided with a control device for controlling the rising speed of the weir.
(7) In an apparatus for casting a ribbon cast piece while pressing a pair of side weirs having lower end surfaces formed by inclined surfaces on both end surfaces of a pair of drums and shifting upward, a pressing device for the side weir and a lifting device; , A molten steel spill detector for detecting the molten steel spill of the strip cast discharged from the gap of the drum, and the pressing speed of the side weir by the pressing device or / and according to the signal from the molten steel spill detector A twin-drum type continuous casting apparatus provided with a control device for controlling the rising speed of the side weir by the lifting device.
(8) In a device for casting a ribbon cast piece while pressing a pair of side weirs whose lower end surfaces are inclined surfaces against both end surfaces of a pair of drums and shifting upward, a pressing device for the side weir and a lifting device; A burr detector that detects the occurrence of burrs in the strip cast discharged from the gap between the drums, and a molten steel seepage detector that detects the molten steel seepage of the strip cast discharged from the gap between the drums, A control device is provided that controls the pressing speed of the side weir by the pressing device and / or the rising speed of the side weir by the lifting device based on signals from the burr detector or the molten steel seepage detector. Twin drum type continuous casting equipment.
(9) In the above (6) or (8), the burr detector is a plate thickness meter that measures the plate thickness of the width end portion of the strip cast slab discharged from the gap of the drum. Twin drum type continuous casting equipment.
(10) The twin drum according to (7) or (8), wherein the molten steel seepage detector is a plate width meter for measuring the plate width of the strip cast slab discharged from the gap of the drum. Type continuous casting equipment.
(11) The molten steel seepage detector is a thermometer for measuring the temperature of the width end portion of the strip cast slab discharged from the gap of the drum, as described in (7) or (8) above Twin drum type continuous casting equipment.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram illustrating an embodiment of the present invention. A pair of drums 1 and 1 rotate in directions opposite to each other, and a pair of side weirs 2 are pressed against both end faces of the drum. On the outer peripheral portion of the drum end surface 1a, a drum seal portion 1b protruding in a ring shape having a width w of about 5 to 20 mm shown in FIG. 5 is provided for the purpose of ensuring a seal surface pressure (pressing surface pressure) with the side weir 2. Is provided. Reference numeral 3 denotes a rolling mill that rolls the strip slab S discharged from the gap between the pair of drums 1 and 1.
[0011]
4 is a thickness gauge as a burr detector. As shown in the cross-sectional view of FIG. 7A, the burr is measured by measuring the thickness of the slab end because the slab width end projects vertically. This can be detected. 5 is a sheet width meter 5 as a first molten steel spill detector, and the molten steel spilled portion projects sideways (outside) as shown in the cross-sectional view of FIG. Becomes wider. Therefore, the molten steel seepage part can be detected by measuring a normal (normal) slab end part and a slab width. Moreover, since the molten steel seepage part is hotter than the burr generation part, it can also be detected by measuring the temperature, brightness or color of the slab end. Therefore, the thermometer 6 is used for the second molten steel seepage detector.
[0012]
Note that only one of the first molten steel oozing detector 5 and the second molten steel oozing detector 6 may be installed, and the installation position of the rolling steel 3 or a pinch roll (not shown) is also included. It may be backward. On the other hand, the burr detector 4 detects the overhanging portion of the slab width end in the vertical direction, so the installation position is preferably in front of the rolling mill 3 or the pinch roll where the overhanging portion is not crushed by rolling or the like. A control device 7 controls the pressing speed of the side weir 2 and / or the ascending speed of the side weir 2 based on signals from the plate thickness meter 4 or the plate width meter 5 and the thermometer 6.
[0013]
FIG. 2 is an enlarged cross-sectional view of the lower side surface of the side weir 2, in which an amorphous refractory 9 is filled in a metal case 8, and a refractory brick 10 is embedded in the amorphous refractory 9. A groove (not shown) is provided in a portion facing the drum seal portion 1b (see FIG. 4) of the refractory brick 10, and a ceramic plate such as BN protrudes from the refractory brick 10 and is mounted in the groove. A protruding portion 11 is formed (see FIGS. 5 and 6). A lower end inclined surface 11 a is formed at the lower end of the protrusion 11, and an outer inclined surface 11 b is formed at the outer edge of the protrusion 11 as shown in FIG. 5.
[0014]
FIG. 3 is a side view showing a pressing device and a lifting device for the side weir, and a stiffening body 12 for preventing thermal deformation of the side weir 2 is fixed to the back side of the metal case 8. The central portion of the stiffening body 12 is supported by a support shaft 14 fixedly supported by an elevating support frame 13, and two upper points and one lower point of the stiffening body 12 are hydraulically supported by the support frame 13. Alternatively, it is supported by an electrically driven pressing device 15.
[0015]
The lower portion of the support frame 13 is connected to a hydraulically or electrically driven lifting device 17 that is guided by a vertical guide 16 at a lower portion and fixed to the bottom surface of the vertical guide 16. Accordingly, the side weir 2 is configured to be pressed against the end surfaces 1 a of the pair of drums 1, 1 by the pressing device 15 and to be moved up and down along the drum end surface 1 a by the lifting device 17.
[0016]
Next, a method for casting a ribbon cast piece by the twin drum type continuous casting apparatus of the present invention will be described. In FIG. 2, the protrusion 11 before wear has a thickness indicated by a chain line, and at the start of casting, the upper end 11c of the lower inclined surface is positioned within a range of, for example, 10 to 20 mm above the drum kiss point kp. Further, in FIG. 5, the protrusion 11 before wear has a thickness indicated by a chain line. As shown in FIG. 2, when the upper end 11c of the lower end inclined surface is matched with the above position, in FIG. The side edge 11d coincides with the inner peripheral edge 1c of the drum seal portion.
[0017]
In this state, the side weir 2 shown in FIG. 1 is pressed against the drum end surface 1a to continuously supply the molten steel Y into the hot water pool portion P, and a solidified shell is generated on the peripheral surfaces of the pair of drums 1 and 1. Is rotated in the direction of the arrow so that the pair of solidified shells are pressure-bonded to each other at the drum kiss point kp to cast the strip slab s.
[0018]
During casting, the pressing device 15 (FIG. 3) is operated to press the side weir 2 against the drum end surface 1a at a speed of, for example, 1.0 μm / second, and the lifting device 17 (FIG. 3) is operated to operate the side weir. 2 is continuously shifted intermittently or intermittently at a speed corresponding to the wear speed of the protrusion 11 at, for example, 0.15 mm / min, so that the upper end 11c of the lower inclined surface shown in FIG. Prevents burrs and molten steel from seeping out.
[0019]
However, the area where burrs and molten steel do not bleed out is very narrow, and if the lower end of the side weir is located slightly below the appropriate range, the molten steel is inserted between the drum end face and the side weir as described above and is strong. On the contrary, when the lower end of the side weir is positioned slightly above the proper position, the seepage of molten steel occurs between the lower end of the side weir and the drum kiss point.
[0020]
As shown in FIG. 7 (a), the burr generating portion has a slab width end portion that protrudes upward or downward by about 2 mm on one side, so the plate thickness meter 4 measures the plate thickness at the slab width end portion. To detect. Further, when molten steel seepage occurs, the plate width of the slab increases by about 5 mm. Therefore, the molten steel seepage is detected by measuring the plate width of the slab with the plate width meter 5. Moreover, since the molten steel seepage portion is about 100 ° C. higher than the burr generation portion, the molten steel seepage is also detected by measuring the temperature, brightness, or color of the slab end portion with the thermometer 6.
[0021]
The control device 7 continuously takes in the signals of the plate thickness meter 4, the plate width meter 5 and the thermometer 6 and compares them with the set values. Is lowered from, for example, 1.0 μm / second to 0.5 μm / second, or / and the lifting speed of the side weir 2 is increased from, for example, 0.15 mm / minute to 0.20 mm / minute by the lifting device 17. When the pressing speed of the side weir 2 is decreased, the wear speed of the side weir refractory is reduced with respect to the upward shift amount of the side weir, so that the lower end of the side weir is shifted upward to an appropriate position, and the generation of burrs can be prevented. On the other hand, if the pressing speed of the side weir 2 is increased, the wear speed of the side weir refractory increases with respect to the upward shift amount of the side weir, so the lower end of the side weir is shifted downward to an appropriate position to prevent burrs. it can.
[0022]
On the other hand, when the control device 7 determines that the molten steel has oozed out, the control device 7 increases the pressing speed by the pressing device 15 from, for example, 1.0 μm / second to 1.5 μm / second, or / and by the lifting device 17. The ascending speed of the side weir 2 is reduced from 0.15 mm / min to 0.10 mm / min, for example. When the pressing speed of the side weir 2 is increased, the wear speed of the side weir refractory increases with respect to the upward shift amount of the side weir. Therefore, the lower end of the side weir is shifted downward to an appropriate position, thereby preventing molten steel seepage. On the other hand, when the pressing speed of the side weir 2 is lowered, the wear speed of the side weir refractory is reduced with respect to the upward shift amount of the side weir, so the lower end of the side weir shifts upward to prevent the molten steel from seeping out. it can.
[0023]
In the above description, both the plate width meter 5 and the thermometer 6 are provided as the molten steel seepage detector, but only one of them may be provided. Further, in the above description, examples of a method (Claim 3) and an apparatus (Claim 8) for preventing both burr generation and molten steel seepage are given, but a method for preventing only burr generation (Claim 1). Alternatively, it may be an apparatus (Claim 6), or may be a method (Claim 2) or an apparatus (Claim 7) that prevents only molten steel seepage.
[0024]
【The invention's effect】
According to the present invention, in the twin-drum continuous casting, in the method of extending the life of the side weir refractory by shifting the side weir upward at a speed corresponding to the wear speed, the lower end of the side weir is below the proper position. It is possible to prevent burr generation at both ends of the slab when positioned, and to prevent the molten steel from seeping out from the lower end of the side dam when the lower end of the side dam is positioned above the appropriate position. As a result, continuous casting for 3.5 hours (360 tons) becomes possible, and a slab with good quality can be stably manufactured while achieving cost reduction and improvement in production efficiency by long-time casting.
[Brief description of the drawings]
FIG. 1 is an overall view of a twin-drum type continuous casting apparatus for explaining an embodiment of the present invention.
FIG. 2 is a side sectional view of a lower side dam.
FIG. 3 is a side view of a lifting device and a pressing device for a side weir.
4 is a front view taken along line II in FIG. 3;
5 is a partial cross-sectional view taken along line II-II in FIG.
6 is a cross-sectional plan view taken along line III-III in FIG.
7A and 7B are cross-sectional views of an end portion of a ribbon cast piece, in which FIG. 7A is a cross-sectional view of a burr and FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Drum 1a ... Drum end surface 1b ... Drum seal part 1c ... Inner peripheral edge 2 of drum seal part ... Side dam 3 ... Rolling mill 4 ... Sheet thickness meter (burr detector)
5. Plate width meter (first molten steel oozing detector)
6 ... Thermometer (second molten steel seepage detector)
7 ... Control device 8 ... Metal case 9 ... Indeterminate refractory 10 ... Refractory brick 11 ... Substantially V-shaped protrusion 11a ... Lower end inclined surface 11b of protrusion ... Outer inclined surface 11c of protrusion ... Upper end of lower end inclined surface 11d ... Side edge 12 of outer inclined surface ... Stiffening body 13 ... Lifting support frame 14 ... Support shaft 15 ... Pushing device 16 ... Vertical guide 17 ... Lifting device S ... Strip slab kp ... Drum kiss point Y ... Molten steel P ... Hot water pool g ... Solidified shell B ... Burr C ... Molten steel seepage part

Claims

In a method of casting a strip cast while pressing a pair of side dams having lower end surfaces formed by inclined surfaces on both end surfaces of a pair of drums and shifting upward, the strip cast slab discharged from the gap between the drums A twin-drum continuous casting method characterized by detecting the occurrence of burrs and decreasing the pressing speed of the side weirs and / or increasing the rising speed when burrs are generated.

In a method of casting a strip cast while pressing a pair of side dams having lower end surfaces formed by inclined surfaces on both end surfaces of a pair of drums and shifting upward, the strip cast slab discharged from the gap between the drums A twin-drum continuous casting method that detects molten steel seepage and increases the pressing speed of the side weir or / and decreases the ascent speed when the molten steel seeps.

In a method of casting a strip cast while pressing a pair of side dams having lower end surfaces formed by inclined surfaces on both end surfaces of a pair of drums and shifting upward, the strip cast slab discharged from the gap between the drums Detect burrs and molten steel seepage, and when burrs occur, reduce the pressing speed of the side weir or / and increase the rising speed, and increase the pressing speed of the side weir when the molten steel seeps, or / and A twin-drum continuous casting method characterized by lowering the rising speed.

4. The twin-drum continuous casting method according to claim 1, wherein the occurrence of burrs is detected based on the plate thickness at the width end portion of the strip slab discharged from the gap between the drums.

The molten steel oozing is detected based on the sheet width of the strip cast slab discharged from the gap of the drum or / and the temperature of the width end of the strip cast slab. Drum type continuous casting method.

An apparatus for casting a strip cast piece while pressing a pair of side weirs each having a lower end surface formed of an inclined surface on both end surfaces of a pair of drums and shifting the upper side upward, and the side weir pressing device, the lifting device, and the drum A burr detector for detecting the occurrence of burrs in the strip cast discharged from the gap of the slab, and the pressing speed of the side weir by the pressing device and / or the rising of the side weir by the lifting device according to the signal from the burr detector A twin-drum type continuous casting apparatus provided with a control device for controlling speed.

An apparatus for casting a strip cast piece while pressing a pair of side weirs each having a lower end surface formed of an inclined surface on both end surfaces of a pair of drums and shifting the upper side upward, and the side weir pressing device, the lifting device, and the drum A molten steel spill detector for detecting the molten steel spill from the strip slab discharged from the gap, and the pressing speed of the side weir by the pressing device or / and the lifting device according to a signal from the molten steel spill detector A twin-drum type continuous casting apparatus provided with a control device for controlling the rising speed of the side weir.

An apparatus for casting a strip cast piece while pressing a pair of side weirs each having a lower end surface formed of an inclined surface on both end surfaces of a pair of drums and shifting the upper side upward, and the side weir pressing device, the lifting device, and the drum A burr detector for detecting the occurrence of burrs in the strip cast discharged from the gap of the molten steel, a squeeze detector for detecting molten steel in the strip cast slab discharged from the gap of the drum, and the burr detection Or a control device for controlling the pressing speed of the side weir by the pressing device and / or the rising speed of the side weir by the lifting device according to a signal from the detector or the molten steel seepage detector Continuous casting equipment.

The twin-drum type continuous casting apparatus according to claim 6 or 8, wherein the burr detector is a plate thickness meter for measuring the plate thickness of the width end portion of the strip cast slab discharged from the gap between the drums. .

The twin-drum type continuous casting apparatus according to claim 7 or 8, wherein the molten steel oozing detector is a sheet width meter for measuring a sheet width of a strip slab discharged from a gap between drums.

The twin-drum continuous casting apparatus according to claim 7 or 8, wherein the molten steel oozing detector is a thermometer that measures the temperature of the width end portion of the strip slab discharged from the gap of the drum. .