JPH0557066B2 - - Google Patents

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Publication number
JPH0557066B2
JPH0557066B2 JP10950885A JP10950885A JPH0557066B2 JP H0557066 B2 JPH0557066 B2 JP H0557066B2 JP 10950885 A JP10950885 A JP 10950885A JP 10950885 A JP10950885 A JP 10950885A JP H0557066 B2 JPH0557066 B2 JP H0557066B2
Authority
JP
Japan
Prior art keywords
short side
width
period
speed
horizontal movement
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP10950885A
Other languages
Japanese (ja)
Other versions
JPS61266166A (en
Inventor
Masami Tenma
Wataru Oohashi
Takeyoshi Ninomya
Kazuhiko Tsutsumi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP10950885A priority Critical patent/JPS61266166A/en
Priority to AU47023/85A priority patent/AU554019B2/en
Priority to CA000490523A priority patent/CA1233011A/en
Priority to EP85306509A priority patent/EP0182468B1/en
Priority to DE8585306509T priority patent/DE3578554D1/en
Priority to ES547211A priority patent/ES8702811A1/en
Priority to BR8504644A priority patent/BR8504644A/en
Priority to US06/783,589 priority patent/US4660617A/en
Priority to ES554807A priority patent/ES8704368A1/en
Priority to US06/883,395 priority patent/US4727926A/en
Publication of JPS61266166A publication Critical patent/JPS61266166A/en
Publication of JPH0557066B2 publication Critical patent/JPH0557066B2/ja
Granted legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16Controlling or regulating processes or operations
    • B22D11/168Controlling or regulating processes or operations for adjusting the mould size or mould taper

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

〔産業上の利用分野〕 本発明は鋼の連続鋳造法に関し、詳しくは連続
鋳造中に鋳型短辺を移動せしめて鋳片幅を拡大も
しくは縮小する幅変更方法に関する。 〔従来の技術〕 近年、連続鋳造、特に鋼の連続鋳造において
は、稼働率の向上および鋳片歩留の向上等の要請
から、鋳型への鋳込を停止することなく鋳片幅の
変更を行なう連続鋳造法が実施されるようになつ
てきた。 特に最近、連続鋳造工程と圧延工程を直結化す
る方法が実用化され、製品板幅に応じて連続鋳造
中の鋳片幅を変更する技術はますます重要さを増
している。連続鋳造機の運転を止めずに鋳片幅を
変更する場合においては幅が変化する部分の長さ
を出来るかぎり短かくし、要求される幅に直ちに
変更することが重要である。このために幅変更速
度を上昇させることが必要となつてきた。 連続鋳造における鋳片幅の変更においては、鋳
型短片を何らかの方法で鋳型の中心側または反中
心側へ移動させる操作がおこなわれる。第2図は
鋳型長辺を固定し短辺を移動させる幅変更装置の
一例を概念的に示したものである。すなわち一対
の短辺1a,1bが(図示していない)鋳型振動
テーブルに固定された長辺2a,2bに挾持され
ており、駆動装置(図示せず)により水平方向に
駆動され、鋳片4の幅を鋳造を止めることなく変
更する装置である。かかる装置において幅変更速
度を高速化する場合、短辺を駆動する力の増大並
びに鋳片欠陥の危険性の増大があり、このことが
幅変更の高速化を阻んでいた。 従来の幅変更方法としては、例えば特公昭56−
49173号公報に示されるように短片背面に連接さ
れた水平方向に移動自在で、かつ球面座を支点と
してカム機構の回転駆動によつて揺動可能に構成
された一本のスピンドルによつて行われていた。
即ち前記スピンドルは水平方向の移動と旋回動作
を同時に行うことは可能であるが、実際の幅変更
にあたつてはカム機構により短辺を所定の傾斜角
に傾斜せしめた後、その状態を維持して短辺を平
行移動せしめることが一般的であり、幅変更速度
は極めて遅いものであつた。 一方、例えば特開昭53−60326号公報および特
公昭54−33772号公報で開示されているように、
短辺の上下方向に2本の電動、あるいは油圧式の
駆動装置を取りつけ、この上下2本の駆動装置を
それぞれ制御して高速で幅変更を実施しようとす
る試みも積極的に採用されている。 第3図および第4図は、前記上下2本の駆動装
置を制御して幅変更を実施する具体的方法の一例
を示すものであつて、第3図は幅縮小の場合を説
明するものであり、aで示す第1ステツプでは短
辺1を点線aの如く傾斜させ、第2ステツプでb
の如く平行移動した後、ついで第3ステツプでc
の如く傾斜をもとに戻す方法を示し、又第4図は
幅拡大の場合を説明するものであつて、aで示す
第1ステツプで短片1を点線aの如く傾斜させ、
第2ステツプでbの如く平行移動したのち、第3
ステツプでcの如く傾斜を少なくする方法を示し
ている。 つまり、前記従来はいずれもテーパー変更動作
と平行移動動作とは完全に分離して行なわれてい
た。 ところで前記従来方法において幅変更速度を高
めるためには平行移動速度Vmを高速化する必要
がある。ところが鋳型内で凝固したシエル(凝固
殻)を破断することなく、かつ、このシエルの変
形抵抗力に打ち勝つて平行移動速度Vmを高める
ためには、傾斜変更角△φを大きくしなければな
らないと言う問題がある。 一方、前記傾斜変更角△φを大きくすると、短
辺1と鋳片4との間に隙間、即ちエアーギヤツプ
が生じ、このエアーギヤツプが大きくなると鋳片
4に割れが生じたり、ブレークアウトが発生する
等の問題がある。 このため前記従来方法では平行移動速度Vmを
高めることに限界があり、而して幅変更時間を短
縮することには制限があつた。係る問題を解決す
るために本出願人は前記第1ステツプ及び第3ス
テツプにおいて短辺の上下端を同時に移動させ、
該期間の所要時間を短縮させる方法を開発し、先
に特開昭59−73155号及び特開昭60−33855号とし
て出願した。しかしながらこの方法においても平
行移動の実施を基本的思想としたものであり、平
行移動に達するまでの時間を出来るだけ速くする
ことは可能となつたがそれでもなお幅変更の全所
要時間を短縮するには限界があつた。 〔発明が解決しようとする問題点〕 本発明は前述した従来方法における問題点を抜
本的に解決すると共に前記特開昭59−73155号及
び特開昭60−33855号の更に改良を図るもので、
水平方向駆動装置と、該駆動装置と独立して作動
する旋回駆動装置を備えた鋳型において、連続鋳
造中に鋳片幅を拡大もしくは縮小する幅変更を最
小時間で行わせることにより、幅変更部分を少な
くして歩留りを向上させると共にブレークアウト
(以下BOと言う)や鋳片割れ等の鋳造欠陥の発
生がない安定した操業を可能ならしめる方法を提
供するものである。 〔問題点を解決するための手段〕 前記問題点を解決するための本発明の構成を以
下、説明する。 先ず、本発明に適用される短辺の駆動装置の一
例を第5図に基づいて説明する。第5図において
1は鋳型の短辺を示し、この短辺1の背部には鋳
造方向x及び短辺1の水平移動方向yに直交する
回動軸11を軸支する軸受部12が固着されてい
る。前記回動軸11には水平方向駆動装置(以
下、駆動装置と言う)13が連接されている。軸
受部12には回動アーム120が突設されてお
り、この回動アーム120には、前記水平駆動装
置13上に載置され、かつ水平駆動装置13とは
独立して作動する旋回駆動装置(以下、旋回装置
と言う)14が連接されている。 従つて駆動装置13を前後進、駆動することに
よつて短辺1は水平方向に移動する。又、旋回装
置14を駆動することによつて短辺1は回動軸1
1を支点として回動する。而して回動軸11は幅
変更時、短辺1に作用する総反力の重心点近傍に
位置せしめることが旋回装置14の旋回力が少な
くてすみ効果的えある。一般的に前記重心点の位
置は、後述する第8図に示すようにメニスカス相
当レベルから回動軸11までの距離l1と回動軸
11から短辺下端までの距離l2の比(l1/l
2)が、2〜5の範囲にある。勿論、旋回装置1
4の旋回力に余裕の有る場合や、短辺近傍の機器
配列状況等に応じては、前記回動軸11の位置
を、短辺1の略中心にすること、あるいは鋳造方
向における任意の位置に設定することも可能であ
る。前記回動操作は、短辺1の水平方向の移動
(以下、水平移動と言う)とは独立して行うこと
ができる。つまり、短辺を水平移動させながら回
転操作も同時に行うことができ、又当然のことな
がら水平移動を停止した状態でも回転操作は行な
える。 尚、本発明において前記水平駆動装置13と旋
回駆動装置14を総称して言う時は、以下短辺駆
動装置と言う。 さて、前記短辺駆動装置を備えた鋳型を用いて
連続鋳造中に鋳片幅を変更するに際し、本発明に
おいては前記短辺の移動(前記短辺の水平移動と
回動とを総称して言うときは単に移動と言う)を
該短辺を鋳型中心側へ順次傾ける前傾期と、鋳型
反中心側へ順次傾ける後傾期に区分し、各期間に
おける短辺の水平移動速度の増速率αsを、予め許
容シエル変形抵抗力をパラメータとして求めると
共に、前記旋回装置の角速度ωを下記(1)式で定
め、当該期間中、前記増速率αs及び角速度ωを一
定に維持して幅変更を行うことを特徴とするもの
である。 ω=αs/Uc ……(1) 但し、 ω;旋回装置の角速度(rad/min) αs;短辺の水平方向移動速度の増速率(mm/
min2) Uc;鋳造速度(mm/min) 尚、前記幅変更方法において、圧延条件及び、
もしくは短辺駆動装置の制約条件より前記短辺の
最大許容水平移動速度Vmaxを設定し、幅変更前
半部の前傾期、もしくは後傾期における前記短辺
の水平移動速度が前記Vmaxを超える際に、幅変
更前半部と後半部の間に下記(2)及び(3)式で与えら
れる範囲内の平行移動速度Vpで短辺の平行移動
を行わしめ、鋳造欠陥の発生を防止しつつ最短時
間で幅変更を実施することが可能となる。 |Vmax|≧|Vp| ……(2) Vp≧αs1・Tr1 ……(3) 但し、 Vmax;最大許容水平移動速度(mm/min) Vp;平行移動速度(mm/min) αs1;幅変更前半の前傾期又は後傾期の短辺の水
平方向移動速度の増速率(mm/min2) Tr1;幅変更前半の前傾期又は後傾期の所要時
間 更に前記幅変更方法において、幅変更開始時の
テーパー量と幅変更終了時の目標テーパー量の差
から生じる目標幅変更量に対する誤差を、前傾期
から後傾期、もしくは後傾期から前傾期へ移行す
る間に平行移動期間を設けることにより吸収する
ことが好ましい。 〔作用〕 第1図は本発明に基づく基本的な幅変更方法を
説明するもので、幅変更時における短辺の水平移
動速度と、回動速度を説明する線図である。第1
図aは幅縮小を、第1図bは幅拡大を示すもの
で、水平移動速度は鋳型中心側への移動速度を正
(プラス)、鋳型反中心側への移動速度を負(マイ
ナス)として表した。又、回動速度は旋回装置の
角速度ωで表し、後述する第6図に示す傾斜角β
が大きくなる方向、即ち短辺が鋳型中心側に傾い
ていく方向を正(プラス)、逆に前記傾斜角βが
小さくなる方向、即ち短辺が鋳型反中心側に傾い
ていく方向を負(マイナス)として表した。 而してまず第1図aに基づき幅縮小の場合につ
いて説明する。 図において実線aは短辺の水平移動速度Vhを、
実線bは旋回装置の角速度ωである。幅縮小にあ
たつては短辺を鋳型中心方向に移動させるが、そ
の前半では短辺を鋳型中心側へ傾ける前傾操作を
行い、目標とする幅変更量の略半量に達したら平
行移動を行うことなく直ちに短辺を鋳型反中心側
へ傾ける後傾操作を行わしめ一連の幅変更操作を
終わる。第6図はこの幅縮小時の短辺の移動状況
を示す模式図である。 前記幅変更操作中における短辺の水平移動速度
Vhは、前後傾期(前記前傾操作を行う期間を前
傾期、後傾操作を行う期間を後傾期と言い、それ
を総称して前後傾期と言う)において一定の増速
率αs、即ち前傾期においては正方向、つまり鋳型
中心側への移動速度が増加する増速率αsを、又、
後傾期においては負方向、つまり鋳型中心側への
移動速度が減少する増速率αs〔正方向を基準とす
れば減速率となるが本発明では増速率に統一して
用い、それを区別して表す必要があるときはその
符合で増速を(+)、減速を(−)で表すことに
する。またこれを総称して言うときは以下増速率
αsと言う。〕を有し、それぞれ時間と共に増加も
しくは減少する。増速率αsは後述するように、予
め許容シエル変形抵抗力をパラメータとして求め
られる。 一方、前傾期における短辺は、当該操業時の鋳
造速度及び前記増速率αsとより前記(1)式で求めら
れる正方向の一定の角速度ωに制御されて回動せ
しめられ、第6図の1点鎖線で示す水平線zに対
する短辺1の傾斜角βが順次大きくなつて、前傾
量は順次増していく。逆に後傾期には、負方向の
一定の角速度ωで短辺は回動し、前記傾斜角βは
順次小さくなり前傾量が減つていく。 而して第1図においては前傾期における増速率
をαs1、角速度をω1で、又、後傾期における増
速率をαs2、角速度をω2で表し、前傾期から後
傾期への折返し時間をTr、幅変更に要する全時
間をTwで示した。 次に幅拡大の場合を前記第1図b及び第7図の
模式図に基づいて説明する。幅拡大を実施するに
当たつては前記幅縮小とは逆に短辺を鋳型反中心
方向に移動させていくが、まずその前半では負方
向の一定の角速度ωで短辺を回動せしめつつ、前
述したように一定の増速率αsを有する水平移動速
度で後傾、移動を行わしめ、所定量の移動を行わ
せた後直ちに正方向の角速度に切り替え前傾操作
を行う。この幅拡大の前後傾操作においても短辺
の水平移動速度は増速率αsを有し、それぞれ時間
と共に増速もしくは減速される。尚、前記第1図
において、幅変更の前半部(幅縮小時は後傾期、
幅拡大時は前傾期)から後半部(幅縮小時は後傾
期、幅拡大時は前傾期)へ移行する際の水平移動
速度Vhにずれが生じているのは、短辺の回動支
点が後述する第8図に示すようにその中心位置か
らずれる(l1>l2)ことによるもので、短辺
の略中心位置に回動支点が有る場合には(l1=
l2)、前記ずれが生じることは無く、前半部終
了時の水平移動速度Vhが後半部の後傾期、もし
くは前傾期開始時の水平移動速度Vhとなる。 以上のように本発明では前記増速率αsを後述す
るように許容シエル変形抵抗をパラメータとして
鋼種や鋳片サイズ、鋳造速度、等に応じて予め求
めて設定すると共に旋回装置の角速度ωを前記(1)
式に基づいて定め、前傾期及び後傾期のそれぞれ
の期間中それを一定に維持して幅変更を実施する
ことにより後述する種々の多大な効果を挙げるこ
とに成功したものである。 さて次に前述した増速率αs及び角速度ωを制御
因子とすることにより本発明の幅変更が効率的に
実施出来る理由について説明する。 前述したように幅変更時の速度を高速化するに
は、幅変更中にBOや鋳片に欠陥等を生じさせな
いための配慮が必要である。このためには幅変更
実施の全期間中において鋳片と短辺との間にエア
ーギヤツプを生じさせず、かつ短片によつて過度
に鋳片を押し込むことがないように常に適正な押
し込みを確保することが肝要である。 第8図は前記第5図の短辺駆動装置を用いて、
連続鋳造中に短辺を移動させる際の鋳片と短辺の
相対的動きを説明する構成図である。而してこの
第8図に基づいて幅変更時、鋳片に生じる歪につ
いて先ず説明する。尚、第8図において1uは短
辺のメニスカス相当部であり、1lは短辺下端部で
あつて、βは短辺と水平線zとの傾斜角を、又、
垂直線に対する傾斜角をθ(θ=β−90°)として
表すものである。 或る時刻tにおいて短辺1がB1の位置にあ
り、微小時間dt経過する間にB2の位置まで移動
すると仮定する。この微小時間dtの間の水平移動
速度をVh、角速度をωとする。又、微小時間dt
の間に短辺のメニスカス相当部1uはdYu、短辺
下端部1lはdYl、移動する。この時、時刻tに
おいてメニスカス相当部1uにあつた鋳片4uは
dt時間後に4u1に、短辺下端部1lにあつた鋳片
4lは4l1に移動する。この移動距離は〔Uc・
dt〕となる。 短辺がB1からB2へ移動することによつて鋳
片は見掛け上、メニスカス相当部でdYu、短辺下
端部でdYl押し込まれるが、実際には前述のよう
に鋳片が〔Uc・dt〕、下方に移動することから、
この移動による水平方向変位〔Uc・dt・tanθ〕
分の変形は緩和される。従つて実際に鋳片が受け
る変形量を、メニスカス相当部でηu、短辺下端
部でηlとすれば、7μ及びηlは下記(4)及び(5)式で与
えられる。 dηu=dYu−Uc・dt・tanθ ……(4) dηl=dYl−Uc・dt・tanθ ……(5) 一方、短辺の水平方向の変位量をXとし、短辺
の傾斜角がdt間にdθ変位するものとすれば、
dYu,dYlは下記(6)及び(7)式で表せる。 dYu=l1・tan(θ+dθ)+dX−l1・tanθ ……(6) dYl=−l2・tan(θ+d)+dX−(−l2・tanθ)
……(7) 但し、 l1;メニスカス相当部1uから駆動装置(第5図の
回動軸11)までの距離 l2;短辺下端部1lから駆動装置(第5図の回動
軸11)までの距離 前記θは小さいことから実質上は下記のように
近似式が成立する。 tanθ≒θ ……(8) 前記(8)式を前記(6),(7)に代入すれば下記(9),(10)
式が得られ、更に(8)〜(10)式を前記(4),(5)式に代入
することによつて下記(11),(12)式が求められ
る。 dYu=l1・dθ+dX ……(9) dYl=−l2・dθ+dX ……(10) dηu=l1・dθ+dX−Uc・dt・θ ……(11) dηl=−l2・dθ+dX−Uc・dt・θ ……(12) (11),(12)式をdtで割れば下記(13),(14)
式が求まる。 dηu/dt=ηu=l1・dθ/dt+dX/dt−Uc・θ
……(13) dηl/dt=η・l=l2・dθ/dt+dX/dt−Uc・θ
……(14) 此処で、dηu/dt=η・u,dηl/dt=η・lは単位
時間当たりの実変形量、即ち変形速度を表す。
又、dθ/dtは短辺の傾斜角度の時間変化、即ち角
速度ωを表す。更にdX/dtは短辺の水平方向変
位の時間変化、即ち水平移動速度Vhを表す。 次に鋳片の変形量を、変形を生じる長さ、つま
り鋳片幅の半量で割れば鋳片の歪が求められる。
即ち前記(13),(14)式を鋳片幅2Wの半量Wで
割ると、歪速度ε・が下記(15),(16)で求められ
る。 ε・u=l1・ω/W+Vh/W−Uc・θ/W
……(15) ε・l=−l2・ω/W+Vh/W−Uc・θ/W
……(16) 前記歪速度を時間的に変化させない、即ち鋳片
の変形を常に適正に保つためには、〔dε・u/dt
=0〕、〔dε・l/dt=0〕であれば良い。従つて
下記(17),(18)式の条件が成立すれば良い。 dε・u/dt=(l1/W)・dω/dt+(1/W)・
dVh/dt−(Uc/W)・ω≡0 ……(17) dε・l/dt=(−l2/W)・dω/dt+(1/
W)・dVh/dt−(Uc/W)・ω≡0 ……(18) (17),(18)式より下記(19)式が求まる。 dω/dt=0 ……(19) (19)式を解くと下記(20)式となり、又
(19)式を前記(17),(18)式に代入すると、下
記(21)式となる。 ω=β ……(20) 但し β;積分定数 dVh/dt=Uc・ω ……(21) 前記(21)式の右辺は時間に対して定数である
のでこれをAとおくと、(22)式のように表され
る。 dVh/dt=Uc・ω≡A ……(22) この(22)式を解けば、その一般解が下記
(23)のように求まる。 Vh=A・t+γ ……(23) 但し γ;積分定数 又、前記(22)式より下記(1)′が求まる。 ω=A/Uc ……(1)′ つまり(23)及び(1)′式より、前述した時間的
に歪速度を変化させず、鋳辺の変形を常に適正に
保つためには、短辺の水平移動速度Vhを幅変更
開始からの経過時間tとの1次関数で設定すれば
良く、又角速度ωをAと鋳辺速度Ucから求まる
一定の値に常に保てば良いと言う新知見が得られ
た。 本発明者等は該知見に基づき実操業の連続鋳造
中における幅変更においてさらに研究を重ねた結
果、前記(23)及び(1)′式の定数Aを許容変形抵
抗力をパラメーターとして求めた値に設定するこ
とにより、前記知見を工業的規模で適用すること
が可能であることを確認した。 而して本発明における前記定数Aは零以外の値
であつて、このため水平移動速度Vhは時間と共
に増速もしくは減速される。この幅変更期間中
Vhを増速もしくは減速させる定数Aを本発明で
は増速率αsとして用いた。又前記(23)及び(1)′
式における積分定数γは水平移動速度Vhの幅変
更開始時の初期速度であり、幅変更やその時の操
業条件によつて予め適宜決定すればよい。前記増
速率αsが設定されると角速度ωは当該操業時の鋳
造速度Ucから ω=αs/Uc ……(1) と求められ、前述した(1)式が得られる。 さて次に、本発明に基づく具体的な幅変更方法
について説明する。 前述したように幅変更中に鋳片に生じる歪を一
定に保持するためには、水平移動速度Vhの増速
率αsと角速度ωを一定に保持して行えば良いこと
が判り、その際の角速度ωは増速率αsと鋳片速度
Ucから前記(1)式で求めらる。従つてαsが正の場
合はωも正となり、短辺は前傾する。逆にαsが負
の場合はωも負となり、短辺は後傾する。 幅変更の終了時には幅変更開始時とほぼ同程度
まで短辺の傾斜角を復帰させる必要があるため、
一連の幅変更を行うためにはαsが正負の期間を
各々、最低1以上、必要とする。αsの正負の期間
の組合せによつて種々の幅変更が可能となるが、
その中で最も単純でかつ高速度の得られるのは第
1図に示すようにαsが正負それぞれ1つづつで構
成された場合である。つまり幅変更の全期間を前
傾期と後傾期とに区分した場合である。 そこで幅変更の前半部と後半部の水平移動速度
Vh及び角速度ωをそれぞれ添字(1は前半部、
2は後半部)を付して表すと以下のように置くこ
とができる。 前半部 Vh1=αs1・t+γ1 ……(24) ω1=αs1/Uc ……(25) 後半部 Vh2=αs2・t+γ2 ……(26) ω2=αs2/Uc ……(27) (24)〜(27)式を前記(15),(16)式に代入
すると各期間の歪速度が下記(28)〜(31)式の
ように求まる。 前半部 ε・u1=(l1/W)・(αs1/Uc)+γ1/W
……(28) ε・l1=(−l2/W)・(αs1/Uc)+γ1/W
……(29)後半部 ε・u2=(l1/W)・(αs2/Uc)+γ2/W−αs
1・Tr/W ……(30) ε・l2=(−l2/W)・(αs2/Uc)+γ2/W−α
s
1・Tr/W ……(31) ところで前記歪速度ε・はそれが負となるとエア
ーギヤツプが生じ、或る値以上となると、短辺駆
動装置の駆動力が著しく増大したり、鋳片が座屈
現象を起こし安定した鋳造ができなくなる。而し
て前記(28)〜(31)式の歪速度ε・は次の条件を
満たす必要がある。 0≦ε・ij≦ε・maxi ……(32) 但し i;短辺のメニスカス相当部u、又は下端部l j;幅変更の前半部、又は後半部 従つて前記(28)〜(31)式に(32)式を代入
すると下記(33)〜(36)が成立する。 0≦(l1/W)・(αs1/Uc)+γ1/W≦ε・max
u ……(33) 0≦(−l2/W)・(αs1/Uc)+γ1/W≦ε・
max l ……(34) 0≦(l1/W)・(αs2/Uc)+γ2/W−αs1・
Tr/W≦ε・max u ……(35) 0≦(−l2/W)・(αs2/Uc)+γ2/W−αs
1・Tr/W≦ε・max l ……(36) 以上の各式を満足する、即ち幅変更中において
安定鋳造を維持するための相関を整理すると下記
(a)〜(h)の各式が求まる。 γ1≧−l1・(αs1/Uc) ……(a) γ1≧W{ε・max u−(l1・W)・(αs1/Uc)}

−l1/(αs1/Uc)+W・ε・max u ……(b) γ1≧l2・(αs1/Uc) ……(c) γ1≧l2・(αs1/Uc)+W・ε・max l ……(d) γ2>αs1・Tr−l1・(αs2/Uc) ……(e) γ2≦−l1・(αs2/Uc)+αs1・Tr+W・ε・
max u ……(f) γ2>αs1・Tr+l2・(αs2/Uc) ……(g) γ2≦l2・(αs2/Uc)+αs1・Tr+W・ε・max
l ……(h) 第9図はこの(a)〜(h)の関係を前述した前半部と
後半部とに区別して表したもので第9図aが前半
部の、また第9図bが後半部を示す。更に横軸は
増速率αs1,αs2を、縦軸は初期速度γ1,γ2であ
る。該第9図におけるハツチング部Dが鋳造欠陥
の発生することのない、つまり安定した鋳造を継
続しつつ幅変更が可能な範囲を示している。従つ
て増速率αs1,αs2及び初期速度γ1,γ2を前記ハ
ツチング部Dの範囲内の任意の値を選択し設定す
ることにより前述した本発明の幅変更が実施でき
る。 ところで幅変更は前述したように可能な限りに
おいて短時間で実施することが要求されており、
係る要求を満足すべき増速率αsを前記ハツチング
部Dの範囲内より求めることが必要である。而し
て幅縮小の前半部では増速率αsが正で、その絶対
値が大きい程よい。このことより第9図aに示し
た点P1が最適条件となる。又、幅拡大の前半期
では増速率αsが負で、しかもその絶対値が大きい
程より。従つて点P3が最適である。 次に、幅変更の後半部においては前半期で通常
操業時より傾斜せしめた傾斜角を元に戻さねばな
らないことから ω1・Tr=−ω2・(Tw−Tr) ……(37) ω1=αs1/Uc,ω2=αs2/Ucであるから Tw−Tr=−(αs1/αs2)・Tr ……(38) となり、幅変更時間を小さくするためにはαs2の
絶対値は大きい程よいことになり、幅縮小の場合
は第9図bに示した点P2が、又、幅拡大の場合
は第9図aに示した点P4が最適点となる。 以上のように幅変更時間を最短にするための増
速率αsが求められるが下記第1表はそれを一覧と
して表したものである。
[Industrial Application Field] The present invention relates to a method for continuous casting of steel, and more particularly to a method for changing the width of a slab by moving the short side of the mold during continuous casting. [Prior art] In recent years, in continuous casting, especially continuous casting of steel, it has become necessary to change the slab width without stopping pouring into the mold due to demands for improved operating efficiency and slab yield. Continuous casting methods have come into use. Particularly recently, a method of directly linking the continuous casting process and the rolling process has been put into practical use, and the technology of changing the width of the slab during continuous casting according to the width of the product sheet is becoming increasingly important. When changing the slab width without stopping the operation of the continuous casting machine, it is important to make the length of the portion where the width changes as short as possible and to immediately change the width to the required width. For this reason, it has become necessary to increase the width change speed. To change the slab width in continuous casting, an operation is performed in which the short mold piece is moved toward the center or away from the center of the mold by some method. FIG. 2 conceptually shows an example of a width changing device that fixes the long sides of the mold and moves the short sides. That is, a pair of short sides 1a and 1b are held between long sides 2a and 2b fixed to a mold vibration table (not shown), and are driven in the horizontal direction by a drive device (not shown), so that the slab 4 This is a device that changes the width of the mold without stopping casting. When increasing the width changing speed in such equipment, there is an increase in the force driving the short side and an increased risk of slab defects, which has hindered the speeding up of the width changing. As a conventional width changing method, for example,
As shown in Publication No. 49173, this is carried out by a single spindle connected to the back of the short piece, which is movable in the horizontal direction and is configured to be swingable by the rotational drive of a cam mechanism using a spherical seat as a fulcrum. I was worried.
That is, the spindle can move in the horizontal direction and rotate at the same time, but when actually changing the width, the short side is tilted to a predetermined angle by a cam mechanism and then maintained in that state. Generally, the width is changed at a very slow speed. On the other hand, as disclosed in, for example, Japanese Patent Application Laid-Open No. 53-60326 and Japanese Patent Publication No. 54-33772,
Attempts are being actively made to install two electric or hydraulic drive devices in the vertical direction of the short side and control these two drive devices, respectively, to change the width at high speed. . 3 and 4 show an example of a specific method of controlling the two upper and lower drive devices to change the width, and FIG. 3 explains the case of width reduction. In the first step indicated by a, the short side 1 is inclined as shown by the dotted line a, and in the second step b
After parallel movement as shown, then in the third step c
4 shows a method of returning the inclination to its original value, and FIG.
After parallel movement as shown in b in the second step, the third step
Step c shows how to reduce the slope. In other words, in all of the above-mentioned conventional art, the taper change operation and the parallel movement operation were performed completely separately. However, in the conventional method, in order to increase the width change speed, it is necessary to increase the parallel movement speed Vm. However, in order to increase the parallel movement speed Vm without breaking the shell solidified in the mold and to overcome the deformation resistance of this shell, the angle of inclination change △φ must be increased. I have a problem to say. On the other hand, when the inclination change angle △φ is increased, a gap, ie, an air gap, is created between the short side 1 and the slab 4, and when this air gap becomes large, cracks occur in the slab 4, breakout occurs, etc. There is a problem. Therefore, in the conventional method, there is a limit to increasing the parallel movement speed Vm, and there is a limit to shortening the width change time. In order to solve this problem, the applicant moves the upper and lower ends of the short sides simultaneously in the first step and the third step,
A method for shortening the time required for this period was developed and filed as Japanese Patent Application Laid-Open Nos. 59-73155 and 60-33855. However, even in this method, the basic idea is to perform parallel movement, and although it is possible to make the time to reach parallel movement as fast as possible, it is still necessary to shorten the total time required to change the width. has reached its limit. [Problems to be Solved by the Invention] The present invention fundamentally solves the problems in the conventional methods described above, and further improves the above-mentioned JP-A-59-73155 and JP-A-60-33855. ,
In molds equipped with a horizontal drive and a swivel drive that operates independently of the drive, width changes during continuous casting that expand or reduce the width of the slab can be made in a minimum amount of time. The purpose of this invention is to provide a method that improves yield by reducing BO and enables stable operation without the occurrence of casting defects such as breakouts (hereinafter referred to as BO) and cracking of slabs. [Means for Solving the Problems] The configuration of the present invention for solving the above problems will be described below. First, an example of a short-side drive device applied to the present invention will be explained based on FIG. 5. In FIG. 5, 1 indicates the short side of the mold, and a bearing 12 is fixed to the back of this short side 1, which supports a rotating shaft 11 perpendicular to the casting direction x and the horizontal movement direction y of the short side 1. ing. A horizontal drive device (hereinafter referred to as a drive device) 13 is connected to the rotation shaft 11 . A rotating arm 120 is protruded from the bearing portion 12 , and a rotating arm 120 includes a rotating drive device that is placed on the horizontal drive device 13 and operates independently of the horizontal drive device 13 . (hereinafter referred to as a turning device) 14 are connected. Therefore, by driving the drive device 13 back and forth, the short side 1 is moved in the horizontal direction. In addition, by driving the turning device 14, the short side 1 becomes the turning axis 1.
Rotates around 1 as a fulcrum. Therefore, when changing the width, it is effective to position the rotating shaft 11 near the center of gravity of the total reaction force acting on the short side 1, since the turning force of the turning device 14 can be reduced. In general, the position of the center of gravity is determined by the ratio (l1/l
2) is in the range of 2-5. Of course, the swivel device 1
4, or depending on the arrangement of equipment near the short side, etc., the position of the rotating shaft 11 may be approximately at the center of the short side 1, or at any position in the casting direction. It is also possible to set it to . The rotation operation can be performed independently of the movement of the short side 1 in the horizontal direction (hereinafter referred to as horizontal movement). In other words, the rotation operation can be performed while horizontally moving the short side, and the rotation operation can also be performed even when the horizontal movement is stopped. In the present invention, when the horizontal drive device 13 and the swing drive device 14 are collectively referred to as a short-side drive device, hereinafter. Now, when changing the slab width during continuous casting using a mold equipped with the short side drive device, in the present invention, the movement of the short side (horizontal movement and rotation of the short side are collectively referred to as The short side is divided into a forward tilting period in which the short side is sequentially tilted toward the center of the mold, and a backward tilting period in which the short side is sequentially tilted toward the mold center side, and the acceleration rate of the horizontal movement speed of the short side in each period is calculated. α s is determined in advance using the allowable shell deformation resistance force as a parameter, and the angular velocity ω of the turning device is determined by the following formula (1), and during the period, the speed increase rate α s and the angular velocity ω are kept constant and the width is It is characterized by making changes. ω=α s /U c ...(1) However, ω: Angular velocity of the swing device (rad/min) α s : Acceleration rate of horizontal movement speed of the short side (mm/min)
min 2 ) U c ; Casting speed (mm/min) In addition, in the width changing method described above, rolling conditions and
Alternatively, the maximum allowable horizontal movement speed Vmax of the short side is set based on the constraints of the short side drive device, and when the horizontal movement speed of the short side during the forward tilting period or backward tilting period of the first half of width change exceeds the above Vmax. In order to prevent the occurrence of casting defects, the short side is translated in parallel between the first half and the second half of the width at a translation speed Vp within the range given by equations (2) and (3) below. It becomes possible to change the width in time. |Vmax|≧|Vp| …(2) Vp≧α s 1・T r 1 …(3) However, Vmax: Maximum allowable horizontal movement speed (mm/min) Vp: Parallel movement speed (mm/min) α s 1; Increase rate of horizontal movement speed of the short side during the forward tilting period or backward tilting period in the first half of width change (mm/min 2 ) T r 1; Required time for the forward tilting period or backward tilting period in the first half of width change Furthermore, in the width changing method, the error with respect to the target width change amount resulting from the difference between the taper amount at the start of the width change and the target taper amount at the end of the width change is calculated from the forward tilt period to the backward tilt period or from the backward tilt period to the forward tilt period. It is preferable to absorb by providing a parallel movement period during the transition to the phase. [Function] Fig. 1 explains the basic width changing method based on the present invention, and is a diagram illustrating the horizontal movement speed and rotation speed of the short side when changing the width. 1st
Figure a shows the width reduction, and Figure 1 b shows the width expansion.The horizontal movement speed is defined as positive (plus) for the movement towards the center of the mold and negative (minus) for the movement towards the side away from the center of the mold. expressed. In addition, the rotation speed is expressed by the angular velocity ω of the rotation device, and the inclination angle β shown in FIG.
The direction in which the angle of inclination β increases, that is, the direction in which the short side leans toward the center of the mold, is positive (plus), and conversely, the direction in which the inclination angle β decreases, that is, the direction in which the short side leans away from the center of the mold, is negative ( (minus). First, the case of width reduction will be explained based on FIG. 1a. In the figure, the solid line a represents the horizontal movement speed Vh of the short side,
The solid line b is the angular velocity ω of the swing device. When reducing the width, the short side is moved toward the center of the mold, but in the first half, the short side is tilted forward toward the center of the mold, and when it reaches approximately half of the target width change, it is moved in parallel. Without doing so, immediately perform a backward tilting operation to tilt the short side toward the side opposite to the center of the mold, and the series of width changing operations is completed. FIG. 6 is a schematic diagram showing the movement of the short side when the width is reduced. Horizontal movement speed of the short side during the width change operation
Vh is a constant acceleration rate α s during the longitudinal tilt period (the period in which the forward tilting operation is performed is called the forward tilting period, the period in which the backward tilting operation is performed is called the backward tilting period, and these are collectively referred to as the longitudinal tilting period). , that is, the speed increase rate α s at which the moving speed increases in the forward direction, that is, toward the center of the mold, in the forward tilting phase, and
In the backward tilting phase, the speed increasing rate α s decreases the moving speed toward the negative direction, that is, toward the mold center. If it is necessary to express them separately, increase in speed will be expressed as (+) and deceleration will be expressed as (-). In addition, when referring to this collectively, it will be hereinafter referred to as the speed increase rate α s . ], each of which increases or decreases over time. As described later, the speed increase rate α s is determined in advance using the allowable shell deformation resistance force as a parameter. On the other hand, the short side in the forward tilting phase is rotated while being controlled to a constant angular velocity ω in the positive direction determined by the above equation (1) based on the casting speed during the operation and the speed increase rate α s. The inclination angle β of the short side 1 with respect to the horizontal line z indicated by the dashed line in the figure gradually increases, and the amount of forward inclination gradually increases. On the other hand, during the backward tilt period, the short side rotates at a constant angular velocity ω in the negative direction, and the inclination angle β gradually decreases, so that the amount of forward tilt decreases. In Fig. 1, the speed increase rate in the forward tilt period is represented by α s 1 and the angular velocity is represented by ω1, and the speed increase rate in the backward tilt period is represented by α s 2 and the angular velocity is represented by ω2. The turnaround time is shown as Tr, and the total time required to change the width is shown as Tw. Next, the case of width expansion will be explained based on the schematic diagrams of FIG. 1b and FIG. 7. When enlarging the width, contrary to the width reduction described above, the short side is moved in the direction away from the center of the mold, but in the first half, the short side is rotated at a constant angular velocity ω in the negative direction. As described above, the rearward tilting and movement is performed at a horizontal movement speed having a constant speed increase rate α s , and after the predetermined amount of movement is performed, the angular velocity is immediately switched to the positive direction and the forward tilting operation is performed. Even in this forward/backward tilting operation for widening the width, the horizontal movement speed of the short side has an acceleration rate α s and is accelerated or decelerated with time. In addition, in Fig. 1 above, the first half of the width change (when the width is reduced is the retroversion phase,
The reason for the deviation in the horizontal movement speed Vh when transitioning from the forward tilt period (when the width is expanded) to the latter half (the backward tilt phase when the width is reduced, and the forward tilt phase when the width is expanded) is due to the rotation of the short side. This is due to the fact that the pivot point deviates from its center position (l1>l2) as shown in FIG.
l2), the above-mentioned deviation does not occur, and the horizontal movement speed Vh at the end of the first half becomes the horizontal movement speed Vh at the beginning of the rearward tilting period or the forward tilting period of the second half. As described above, in the present invention, the speed increase rate α s is determined and set in advance according to the steel type, slab size, casting speed, etc. using the allowable shell deformation resistance as a parameter, as will be described later. (1)
By determining the width based on the formula and changing the width while keeping it constant during each of the anteversion period and the retroversion period, we succeeded in achieving various great effects as described below. Next, the reason why the width change of the present invention can be efficiently implemented by using the speed increase rate α s and the angular velocity ω as control factors will be explained. As mentioned above, in order to increase the speed when changing the width, it is necessary to take care to prevent defects from occurring in the BO or slab during the width change. To achieve this, it is necessary to ensure proper pushing at all times so that no air gap is created between the slab and the short side, and the slab is not pushed in excessively by the short piece during the entire width change implementation period. That is essential. FIG. 8 shows using the short side drive device of FIG. 5,
It is a block diagram explaining the relative movement of a slab and a short side when moving a short side during continuous casting. Based on FIG. 8, we will first explain the strain that occurs in the slab when the width is changed. In FIG. 8, 1u is a part corresponding to the meniscus of the short side, 1l is the lower end of the short side, β is the inclination angle between the short side and the horizontal line z, and
The angle of inclination with respect to the vertical line is expressed as θ (θ=β−90°). Assume that the short side 1 is at a position B1 at a certain time t, and moves to a position B2 during a minute time dt. The horizontal movement speed during this minute time dt is Vh, and the angular velocity is ω. Also, minute time dt
During this period, the short side meniscus equivalent portion 1u moves by dYu, and the short side lower end 1l moves by dYl. At this time, the slab 4u that was in the meniscus equivalent part 1u at time t is
After time dt, the slab 4l located at the lower end 1l of the short side moves to 4l1. This travel distance is [Uc・
dt]. As the short side moves from B1 to B2, the slab is apparently pushed in by dYu at the part corresponding to the meniscus and dYl at the lower end of the short side, but in reality, as mentioned above, the slab is pushed into [Uc・dt] , from moving downward,
Horizontal displacement due to this movement [Uc・dt・tanθ]
The deformation of the minute is alleviated. Therefore, if the amount of deformation actually experienced by the slab is ηu at the meniscus-equivalent part and ηl at the lower end of the short side, then 7μ and ηl are given by the following equations (4) and (5). dηu=dYu−Uc・dt・tanθ ……(4) dηl=dYl−Uc・dt・tanθ ……(5) On the other hand, let the horizontal displacement of the short side be X, and the inclination angle of the short side is between dt. If dθ is displaced to
dYu and dYl can be expressed by the following formulas (6) and (7). dYu=l1・tan(θ+dθ)+dX−l1・tanθ……(6) dYl=−l2・tan(θ+d)+dX−(−l2・tanθ)
...(7) However, l1: Distance from the meniscus equivalent part 1u to the drive device (rotation shaft 11 in Fig. 5) l2: From the lower end of the short side 1l to the drive device (rotation shaft 11 in Fig. 5) Since the distance θ is small, the following approximate formula holds true. tanθ≒θ ……(8) Substituting the above equation (8) into the above (6) and (7) gives the following (9) and (10)
The following equations (11) and (12) are obtained by substituting equations (8) to (10) into equations (4) and (5). dYu=l1・dθ+dX …(9) dYl=−l2・dθ+dX …(10) dηu=l1・dθ+dX−Uc・dt・θ …(11) dηl=−l2・dθ+dX−Uc・dt・θ … …(12) Dividing equations (11) and (12) by dt gives the following (13) and (14)
Find the formula. dηu/dt=ηu=l1・dθ/dt+dX/dt−Uc・θ
...(13) dηl/dt=η・l=l2・dθ/dt+dX/dt−Uc・θ
...(14) Here, dηu/dt=η·u, dηl/dt=η·l represent the actual amount of deformation per unit time, that is, the deformation speed.
Further, dθ/dt represents the time change in the inclination angle of the short side, that is, the angular velocity ω. Further, dX/dt represents the temporal change in the horizontal displacement of the short side, that is, the horizontal movement speed Vh. Next, the strain in the slab can be determined by dividing the amount of deformation of the slab by the length at which deformation occurs, that is, half the width of the slab.
That is, by dividing the above equations (13) and (14) by half W of the slab width 2W, the strain rate ε· can be obtained from the following equations (15) and (16). ε・u=l1・ω/W+Vh/W−Uc・θ/W
...(15) ε・l=−l2・ω/W+Vh/W−Uc・θ/W
...(16) In order not to change the strain rate over time, that is, to keep the deformation of the slab always appropriate, [dε・u/dt
=0] and [dε·l/dt=0]. Therefore, it is sufficient if the conditions of equations (17) and (18) below are satisfied. dε・u/dt=(l1/W)・dω/dt+(1/W)・
dVh/dt−(Uc/W)・ω≡0 …(17) dε・l/dt=(−l2/W)・dω/dt+(1/
W)・dVh/dt−(Uc/W)・ω≡0 ...(18) From equations (17) and (18), the following equation (19) can be found. dω/dt=0...(19) Solving equation (19) yields equation (20) below, and substituting equation (19) into equations (17) and (18) above yields equation (21) below. . ω=β ...(20) However, β: integral constant dVh/dt=Uc・ω ...(21) Since the right side of the above equation (21) is a constant with respect to time, if we set it as A, we get (22 ) is expressed as the formula. dVh/dt=Uc・ω≡A...(22) By solving equation (22), the general solution can be found as shown in (23) below. Vh=A・t+γ...(23) However, γ: Integral constant Also, the following (1)' can be found from the above equation (22). ω=A/Uc ……(1)′ In other words, from equations (23) and (1)′, in order to keep the deformation of the cast side at an appropriate level without changing the strain rate over time as described above, it is necessary to New knowledge that it is sufficient to set the horizontal movement velocity Vh as a linear function of the elapsed time t from the start of the width change, and that the angular velocity ω is always kept at a constant value determined from A and the flank velocity Uc. was gotten. Based on this knowledge, the present inventors conducted further research on changing the width during continuous casting in actual operations, and as a result, the constant A in equations (23) and (1)' was determined to be a value using the allowable deformation resistance as a parameter. It was confirmed that it is possible to apply the above knowledge on an industrial scale by setting . The constant A in the present invention has a value other than zero, and therefore the horizontal movement speed Vh is increased or decreased with time. During this width change period
In the present invention, the constant A that accelerates or decelerates Vh is used as the speed increase rate α s . Also, (23) and (1)'
The integral constant γ in the equation is the initial speed of the horizontal movement speed Vh at the start of width change, and may be appropriately determined in advance depending on the width change and the operating conditions at that time. When the speed increase rate α s is set, the angular velocity ω is determined from the casting speed Uc during the operation as follows: ω=α s /Uc (1), and the above-mentioned equation (1) is obtained. Next, a specific width changing method based on the present invention will be explained. As mentioned above, in order to keep the strain generated in the slab constant during the width change, it was found that it is sufficient to keep the acceleration rate α s of the horizontal movement speed Vh and the angular velocity ω constant, and the The angular velocity ω is the speed increase rate α s and the slab velocity
It can be obtained from Uc using the above equation (1). Therefore, if α s is positive, ω will also be positive, and the short side will tilt forward. Conversely, if α s is negative, ω will also be negative, and the short side will tilt backward. At the end of the width change, it is necessary to restore the inclination angle of the short side to almost the same level as at the beginning of the width change.
In order to perform a series of width changes, at least one or more periods are required for each positive and negative period of α s . Various width changes are possible by combining the positive and negative periods of α s ,
Among these, the simplest one and the highest speed can be obtained when α s is configured with one positive and one negative α s as shown in FIG. In other words, this is a case where the entire width change period is divided into a forward tilt period and a backward tilt period. Therefore, the horizontal movement speed of the first half and the second half of the width change
Vh and angular velocity ω are subscripts (1 is the first half,
2 can be expressed as follows by adding the latter half). First half Vh1=α s 1・t+γ1 ……(24) ω1=α s 1/Uc ……(25) Second half Vh2=α s 2・t+γ2 ……(26) ω2=α s 2/Uc ……( 27) By substituting equations (24) to (27) into equations (15) and (16) above, the strain rate for each period can be found as shown in equations (28) to (31) below. First half ε・u1=(l1/W)・(α s 1/Uc)+γ1/W
...(28) ε・l1=(−l2/W)・(α s 1/Uc)+γ1/W
...(29) Second half ε・u2=(l1/W)・(α s 2/Uc)+γ2/W−α s
1・Tr/W……(30) ε・l2=(−l2/W)・(α s 2/Uc)+γ2/W−α
s
1.Tr/W...(31) By the way, if the strain rate ε is negative, an air gap will occur, and if it exceeds a certain value, the driving force of the short side drive device will increase significantly, or the slab will sit. This causes a bending phenomenon and makes stable casting impossible. Therefore, the strain rate ε· in equations (28) to (31) above must satisfy the following conditions. 0≦ε・ij≦ε・maxi ...(32) However, i: the meniscus equivalent part u of the short side, or the lower end lj: the first half or the second half of the width change Therefore, the above (28) to (31) When formula (32) is substituted into formula, the following (33) to (36) hold true. 0≦(l1/W)・(α s 1/Uc)+γ1/W≦ε・max
u...(33) 0≦(-l2/W)・(α s 1/Uc)+γ1/W≦ε・
max l...(34) 0≦(l1/W)・(α s 2/Uc)+γ2/W−α s 1・
Tr/W≦ε・max u……(35) 0≦(−l2/W)・(α s 2/Uc)+γ2/W−α s
1・Tr/W≦ε・max l ...(36) The correlations for satisfying each of the above formulas, that is, maintaining stable casting during width changes, are summarized as follows.
Each equation (a) to (h) is found. γ1≧−l1・(α s 1/Uc) ……(a) γ1≧W{ε・max u−(l1・W)・(α s 1/Uc)}
=
−l1/(α s 1/Uc) + W・ε・max u …(b) γ1≧l2・(α s 1/Uc) …(c) γ1≧l2・(α s 1/Uc)+W・ε・max l ……(d) γ2>α s 1・Tr−l1・(α s 2/Uc) ……(e) γ2≦−l1・(α s 2/Uc)+α s 1・Tr+W・ε・
max u...(f) γ2>α s 1・Tr+l2・(α s 2/Uc) ……(g) γ2≦l2・(α s 2/Uc)+α s 1・Tr+W・ε・max
l...(h) Figure 9 shows the relationship between (a) to (h) by dividing it into the first half and the second half. Figure 9 a is the first half, and Figure 9 b is indicates the second half. Furthermore, the horizontal axis represents the speed increase rates α s 1 and α s 2, and the vertical axis represents the initial speeds γ1 and γ2. The hatched portion D in FIG. 9 indicates a range in which no casting defects occur, that is, a range in which the width can be changed while stable casting is continued. Therefore, by selecting and setting the speed increase rates α s 1, α s 2 and the initial speeds γ1, γ2 to arbitrary values within the range of the hatched portion D, the above-mentioned width change of the present invention can be implemented. By the way, as mentioned above, width changes are required to be carried out as quickly as possible.
It is necessary to find the speed increase rate α s within the range of the hatching portion D that satisfies this requirement. In the first half of the width reduction, the speed increase rate α s is positive, and the larger its absolute value, the better. From this, the point P1 shown in FIG. 9a becomes the optimum condition. Also, in the first half of the width expansion, the speed increase rate α s is negative, and the larger its absolute value is, the more the speed increase rate α s is negative. Therefore, point P3 is optimal. Next, in the second half of the width change, the inclination angle that was made during normal operation in the first half must be returned to its original value, so ω1・Tr=−ω2・(Tw−Tr) ……(37) ω1=α Since s 1/Uc, ω2=α s 2/Uc, Tw−Tr=−(α s 1/α s 2)・Tr ……(38), and in order to reduce the width change time, α s 2 The larger the absolute value of is, the better. In the case of width reduction, the optimum point is the point P2 shown in FIG. 9b, and in the case of width expansion, the point P4 shown in FIG. 9a is the optimum point. As described above, the speed increase rate α s for minimizing the width change time is determined, and Table 1 below shows it as a list.

【表】 而して前記第1表の条件下における水平移動速
度Vh及び角速度ωは下記第2表(幅縮小)及び
第3表(幅拡大)のようになる。
[Table] The horizontal movement speed Vh and angular velocity ω under the conditions shown in Table 1 are as shown in Table 2 (width reduction) and Table 3 (width expansion) below.

【表】【table】

〔実施例〕〔Example〕

350屯/Hの湾曲形連続鋳造機において低炭Al
キルド鋼の製造中に本発明を実施した。本実施例
に用いた短辺駆動装置は前記第5図に示した構成
のものであり、駆動装置13及び旋回装置14に
は、共に油圧式のシリンダー装置を用いた。この
短辺駆動装置と連続鋳造機の設備仕様及び操業条
件は第4表に示す通りである。 さて、本実施例では幅変更時間の最短化を狙つ
て初期速度γ1,γ2を前記第1表のように設定し
た。 一方、α増速率αsはシエル強度から設定される
値では駆動装置のシリンダー能力が不足したので
改めてこのシリンダー能力から求めた。
Low-coal Al in a 350 ton/H curved continuous casting machine
The invention was implemented during the production of killed steel. The short side drive device used in this embodiment has the configuration shown in FIG. 5, and both the drive device 13 and the swing device 14 are hydraulic cylinder devices. The equipment specifications and operating conditions of this short side drive device and continuous casting machine are as shown in Table 4. Now, in this embodiment, the initial speeds γ1 and γ2 are set as shown in Table 1 above with the aim of minimizing the width change time. On the other hand, the α acceleration rate α s was determined from the cylinder capacity since the cylinder capacity of the drive device was insufficient with the value set from the shell strength.

【表】【table】

【表】 而してシリンダーの有効能力Favは前記(38)
式より(16屯−3屯−3屯=10屯)10屯となつ
た。又当該鋼種の引張試験結果よりGo=2.5×
10-12{(Kg/mm2n・Sec}、n=0.32、q=28000
(1/°K)が求められた。又シエル厚の測定に
よりHo=20(mm/min1/2)であつた。この条件下
で増速率αsを逐次変化させ、前記(34)〜(37)
式に基づいて必要駆動力Fを求めた。この結果、
前記必要駆動力Fを10屯以下とするためには、増
速率αsを50mm/min2以下とする必要のあること
が判つた。従つて増速率αsを50mm/min2とした。
これに伴つて角速度ωは前記(1)式よりω=50mm/
min2/1600mm/min=0.03125(rad/min)となつ
た。 前傾期の増速率αs1と後傾期の増速率αs2は前
述したように制御性を高めるためにαs1=αs2と
した。 以上の設定により、水平移動速度Vhと角速度
ωは、幅縮小の場合は以下のように定まつた。 幅縮小時の前傾期 (0≦t≦Tr) Vh=50t+12.5 (mm/min) ω=0.03125 (rad/min) 幅縮小時の後傾期 (Tr≦t≦Tw) Vh=−50t+100Tr+12.5 (mm/min) ω=−0.03125 (rad/min) 尚、折り返し時間Trは、片側の鋳片幅変更量
Sより下記(55)式で求められる。 Tr=0.2{(1.5625+S/2)1/2−1.25}(min)
……(55) さて、前述のように水平移動速度Vh及び角速
度ωを設定し、幅変更時間Twの半量Trまで前傾
移動させ、半量Tr到達後は後傾移動を行い幅縮
小を実施した。第5表は目標幅変更(縮小)量に
対する幅変更時間を従来法と比較して表わしたも
のである。従来法による幅縮小は前記第3図に示
すように上下2本のシリンダーを用い、傾斜角度
を強めたのち平行移動する方法で行つた。この場
合発生エアーギヤツプ量を大きな鋳造欠陥を生じ
ない程度に押さえ、かつ必要駆動力を10屯以下と
して幅縮小を行うためには平行移動速度Vmは15
mm/分が限界であつた。
[Table] Therefore, the effective capacity Fav of the cylinder is (38) above.
From the formula (16 ton - 3 ton - 3 ton = 10 ton) it became 10 ton. Also, from the tensile test results of the steel type, Go=2.5×
10 -12 {(Kg/mm 2 ) n・Sec}, n=0.32, q=28000
(1/°K) was determined. Further, the shell thickness was measured and found to be Ho=20 (mm/min 1/2 ). Under this condition, the speed increase rate α s is successively changed, and the above (34) to (37)
The required driving force F was determined based on the formula. As a result,
It has been found that in order to reduce the required driving force F to 10 tons or less, the speed increase rate α s needs to be 50 mm/min 2 or less. Therefore, the speed increase rate α s was set to 50 mm/min 2 .
Along with this, the angular velocity ω is calculated from equation (1) above: ω=50mm/
min 2 /1600mm/min=0.03125 (rad/min). The speed increase rate α s 1 in the forward tilt period and the speed increase rate α s 2 in the backward tilt period are set to α s 1 = α s 2 in order to improve controllability, as described above. With the above settings, the horizontal movement velocity Vh and angular velocity ω are determined as follows in the case of width reduction. Forward tilt period when width is reduced (0≦t≦Tr) Vh=50t+12.5 (mm/min) ω=0.03125 (rad/min) Backward tilt period when width is reduced (Tr≦t≦Tw) Vh=−50t+100Tr+12 .5 (mm/min) ω=-0.03125 (rad/min) The turn-back time Tr is determined by the following formula (55) from the change amount S of slab width on one side. Tr=0.2 {(1.5625+S/2) 1/2 −1.25} (min)
...(55) Now, as mentioned above, we set the horizontal movement speed Vh and angular velocity ω, moved forward to half the amount Tr of the width change time Tw, and after reaching the half amount Tr, moved backward to reduce the width. . Table 5 shows the width change time relative to the target width change (reduction) amount in comparison with the conventional method. Width reduction by the conventional method was carried out by using two cylinders, upper and lower, as shown in FIG. 3, by increasing the angle of inclination and then moving them in parallel. In this case, in order to suppress the amount of air gap generated to a level that does not cause large casting defects, and to reduce the width with the required driving force of 10 tons or less, the parallel movement speed Vm is 15.
mm/min was the limit.

【表】 この第5表から明らかなように幅縮小量の大小
にかかわらず、本発明の実施例の方が、従来法に
比べて幅変更時間が著しく短いことがわかる。
又、幅縮小量が大きくなるほど本発明の実施例に
よる幅変更時間短縮効果は増大する。 次に幅拡大の場合も前記幅縮小と同様に前記第
3表及び(56)式より、水平移動速度Vh、角速
度ω及び折り返し時間Trが以下のように求まつ
た。 幅拡大時の後傾期 (0≦t≦Tr) Vh=−50t+12.5 (mm/min) ω=−0.03125 (rad/min) 幅拡大時の前傾期 (Tr≦t≦Tw) Vh=50t−100Tr+12.5 (mm/min) ω=0.03125 (rad/min) Tr=0.2{(1.5625+S/2)1/2+1.25}(min)−
(56) 第6表は前記幅縮小と同様に目標幅変更(縮
小)量に対する幅変更時間を従来法と比較して表
わしたものである。 この第6表から明らかなように、幅拡大におい
ても従来法に比較して幅変更時間を著しく短縮で
き、しかも鋳造欠陥の発生も全く認められなかつ
た。
[Table] As is clear from Table 5, the width changing time is significantly shorter in the embodiment of the present invention than in the conventional method, regardless of the amount of width reduction.
Furthermore, the larger the amount of width reduction, the greater the width change time reduction effect achieved by the embodiment of the present invention. Next, in the case of width expansion, the horizontal movement speed Vh, angular velocity ω, and turning time Tr were determined as follows from Table 3 and Equation (56), as in the case of width reduction. Backward tilting period when width increases (0≦t≦Tr) Vh=-50t+12.5 (mm/min) ω=-0.03125 (rad/min) Forward tilting phase when width increases (Tr≦t≦Tw) Vh= 50t−100Tr+12.5 (mm/min) ω=0.03125 (rad/min) Tr=0.2{(1.5625+S/2) 1/2 +1.25}(min)−
(56) Table 6 shows a comparison of the width change time with respect to the target width change (reduction) amount with the conventional method, similar to the width reduction described above. As is clear from Table 6, the width changing time could be significantly shortened compared to the conventional method even when width was expanded, and no casting defects were observed at all.

【表】 (発明の効果) 以上詳述したように本発明の実施により、鋳型
の幅変更が最小時間で可能となつた。このため幅
変更による鋳片の幅が変化する部分を少なくで
き、歩留を著しく向上できた。 加えて鋳片幅1300〜650mmの間で任意量の幅可
変が実施でき、幅変更時のエアーギヤツプ量やシ
エル変形抵抗力を常に許容値以下とでき、鋳片割
れやブレークアウト等のない安定した操業が可能
となつた。
[Table] (Effects of the Invention) As detailed above, by carrying out the present invention, it has become possible to change the width of the mold in a minimum amount of time. For this reason, the portion where the width of the slab changes due to the width change can be reduced, and the yield can be significantly improved. In addition, the slab width can be varied by any amount between 1300 and 650 mm, and the air gap amount and shell deformation resistance force can always be kept below the allowable value when changing the width, resulting in stable operation without slab cracking or breakouts. became possible.

【図面の簡単な説明】[Brief explanation of drawings]

第1図a,bは本発明に基づく幅変更時におけ
る短辺の水平移動速度を説明するための線図、第
2図は周知の幅可変鋳型の一例を示す斜視図、第
3図a,b,c及び第4図a,b,cは従来の幅
変更方法の一例を示す模式図であり、第3図が幅
縮小、第4図が幅拡大である。第5図〜第10図
は本発明に基づく実施例であり、第5図は短辺駆
動装置の一例を示す斜視図、第6図は幅縮小時の
短辺の移動状況を示す模式図、第7図は幅拡大時
の短辺の移動状況を示す模式図、第7図a,bは
短辺の移動と前記エアーギヤツプの生成条件を説
明する概念図、第8図は幅変更時、鋳片に生じる
歪について説明するためのもので、前記第5図の
短辺駆動装置を用いて、連続鋳造中に短辺を移動
させる際の鋳片と短辺の相対的動きを説明する構
成図、第9図は鋳造欠陥の発生することのない増
速率αs、及び短辺の初期速度γの範囲を示す線
図、第10図は幅変更鋳片を示す平面図、第11
図及び第13図は本発明の他の実施例に基づく幅
変更時における短辺の水平移動速度を説明するた
めの線図、第12図はテーパー量変更によつて発
生する幅変更量の誤差を説明するための線図であ
る。 1,1a,1b……短辺、2a,2b……長
辺、4……鋳辺、11……回動軸、12……軸受
部、13……水平駆動装置、14……旋回装置、
120……回動アーム。
FIGS. 1a and 1b are diagrams for explaining the horizontal movement speed of the short side when changing the width according to the present invention, FIG. 2 is a perspective view showing an example of a known variable width mold, and FIGS. b, c and FIGS. 4a, b, c are schematic diagrams showing an example of a conventional width changing method, with FIG. 3 showing width reduction and FIG. 4 showing width expansion. 5 to 10 show examples based on the present invention, FIG. 5 is a perspective view showing an example of a short side drive device, FIG. 6 is a schematic diagram showing the movement status of the short side when the width is reduced, Fig. 7 is a schematic diagram showing the movement of the short side when the width is expanded, Fig. 7 a and b are conceptual diagrams explaining the movement of the short side and the conditions for generating the air gap, and Fig. 8 is a schematic diagram showing the movement of the short side when the width is changed. This diagram is for explaining the strain that occurs in the slab, and is a configuration diagram illustrating the relative movement between the slab and the short side when the short side is moved during continuous casting using the short side drive device shown in Fig. 5. , FIG. 9 is a diagram showing the speed increase rate α s and the range of the short side initial velocity γ without causing casting defects, FIG. 10 is a plan view showing the width-changed slab, and FIG.
13 and 13 are diagrams for explaining the horizontal movement speed of the short side when changing the width according to another embodiment of the present invention, and FIG. 12 shows the error in the width change amount caused by changing the taper amount. FIG. 1, 1a, 1b...short side, 2a, 2b...long side, 4...cast side, 11...rotating shaft, 12...bearing section, 13...horizontal drive device, 14...swivel device,
120... Rotating arm.

Claims (1)

【特許請求の範囲】 1 連続鋳造中に、水平方向駆動装置と、該駆動
装置と独立して作動する旋回駆動装置を介して鋳
型短辺を移動せしめる鋳片幅変更方法において、
前記短辺の移動を該短辺を鋳型中心側へ順次傾け
る前傾期と、鋳型反中心側へ順次傾ける後傾期に
区分し、各期間における短辺の水平方向移動速度
の増速率αsを予め許容シエル変形抵抗力をパラメ
ータとして求めると共に、前記旋回装置の角速度
ωを下記(1)で定め、当該期間中、前記増速率αs
び角速度ωを一定に維持して幅変更を行うことを
特徴とする連続鋳造中における鋳片幅変更方法。 ω=αs/Uc ……(1) 但し、 ω;旋回装置の角速度(rad/min) αs;短辺の水平方向移動速度の増速率(mm/
min2) Uc;鋳造速度(mm/min) 2 連続鋳造中に、水平方向駆動装置と、該駆動
装置と独立して作動する旋回駆動装置を介して鋳
型短辺を移動せしめる鋳片幅変更方法において、
前記短辺の移動を該短辺を鋳型中心側へ順次傾け
る前傾期と、鋳型反中心側へ順次傾ける後傾期に
区分し、各期間における短辺の水平方向移動速度
の増速率αsを予め許容シエル変形抵抗力をパラメ
ータとして求める共に、前記旋回装置の角速度ω
を下記(1)で定め、当該期間中、前記増速率αs及び
角速度ωを一定に維持し、 さらに、圧延条件及び、もしくは短辺駆動装置
の制約条件より前記短辺の最大許容水平移動速度
Vmaxを設定し、幅変更前半部の前傾期、もしく
は後傾期における前記短辺の水平移動速度が前記
Vmaxを越える際に、幅変更前半部と後半部の間
に下記(2)及び(3)式で与えられる範囲内の平行移動
速度Vpで短辺の平行移動を行わしめ、鋳造欠陥
の発生を防止しつつ最短時間で幅変更を実施する
ことを特徴とする連続鋳造中における鋳片幅変更
方法。 ω=αs/Uc ……(1) 但し、 ω;旋回装置の角速度(rad/min) αs;短辺の水平方向移動速度の増速率(mm/
min2) Uc 鋳造速度(mm/min) |Vmax|≧|Vp| ……(2) Vp≧αs1・Tr1 ……(3) 但し、 Vmax;最大許容水平移動速度(mm/min) Vp;平行移動速度(mm/min) αs1;幅変更前半の前傾期又は後傾期の短辺の水
平方向移動速度の増速率(mm/min2) Tr1;幅変更前半の前傾期又は後傾期の所要時
間。
[Claims] 1. A slab width changing method in which the short side of the mold is moved during continuous casting via a horizontal drive device and a swing drive device that operates independently of the drive device, comprising:
The movement of the short side is divided into a forward tilt period in which the short side is sequentially tilted toward the center of the mold, and a backward tilt period in which the short side is sequentially tilted toward the mold center side, and the acceleration rate α s of the horizontal movement speed of the short side in each period is determined. is determined in advance using the allowable shell deformation resistance force as a parameter, and the angular velocity ω of the swing device is determined according to (1) below, and during the period, the width is changed while maintaining the speed increase rate α s and the angular velocity ω constant. A method for changing slab width during continuous casting, characterized by: ω=α s /U c ...(1) However, ω: Angular velocity of the swing device (rad/min) α s : Acceleration rate of horizontal movement speed of the short side (mm/min)
min 2 ) U c ; Casting speed (mm/min) 2 During continuous casting, the width of the slab is changed by moving the short side of the mold via a horizontal drive and a swing drive that operates independently of the drive. In the method,
The movement of the short side is divided into a forward tilt period in which the short side is sequentially tilted toward the center of the mold, and a backward tilt period in which the short side is sequentially tilted toward the mold center side, and the acceleration rate α s of the horizontal movement speed of the short side in each period is determined. is determined in advance using the allowable shell deformation resistance force as a parameter, and the angular velocity ω of the rotating device is determined in advance.
is determined in (1) below, and during the period, the speed increase rate α s and the angular velocity ω are kept constant, and further, the maximum allowable horizontal movement speed of the short side is determined based on the rolling conditions and/or the constraints of the short side drive device.
Vmax is set, and the horizontal movement speed of the short side in the forward tilting phase or backward tilting phase of the first half of the width change is
When exceeding Vmax, the short side is translated at a translation speed Vp within the range given by equations (2) and (3) below between the first half and the second half of the width change to prevent the occurrence of casting defects. A method for changing the width of a slab during continuous casting, characterized by changing the width in the shortest possible time while preventing ω=α s /U c ...(1) However, ω: Angular velocity of the swing device (rad/min) α s : Acceleration rate of horizontal movement speed of the short side (mm/min)
min 2 ) U c casting speed (mm/min) |Vmax|≧|Vp| …(2) Vp≧α s 1・T r 1 …(3) However, Vmax; Maximum allowable horizontal movement speed (mm/min) min) Vp: Parallel movement speed (mm/min) α s 1: Increase rate of horizontal movement speed of the short side during the forward tilting period or backward tilting period in the first half of width change (mm/min 2 ) T r 1: Width change The time required for the first half of the forward tilting phase or backward tilting phase.
JP10950885A 1984-11-09 1985-05-21 Method for changing ingot width Granted JPS61266166A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
JP10950885A JPS61266166A (en) 1985-05-21 1985-05-21 Method for changing ingot width
AU47023/85A AU554019B2 (en) 1984-11-09 1985-09-03 Changing slab width in continuous casting
CA000490523A CA1233011A (en) 1984-11-09 1985-09-12 Method of changing width of slab in continuous casting
EP85306509A EP0182468B1 (en) 1984-11-09 1985-09-13 Method of changing width of slab in continuous casting
DE8585306509T DE3578554D1 (en) 1984-11-09 1985-09-13 METHOD FOR CHANGING THE WIDTH OF A CAST STRAND IN CONTINUOUS CASTING.
ES547211A ES8702811A1 (en) 1984-11-09 1985-09-23 Method for varying the width of a slab cast in a continuous-casting mould
BR8504644A BR8504644A (en) 1984-11-09 1985-09-23 PROCESS FOR CHANGING WIDTH UNDER CONTINUOUS FOUNDATION AND APPLIANCE FOR CONTINUOUS FOUNDRY MOLD, OF THE TYPE OF VARIABLE WIDTH
US06/783,589 US4660617A (en) 1984-11-09 1985-10-03 Method of changing width of slab in continuous casting
ES554807A ES8704368A1 (en) 1984-11-09 1986-05-09 Method for varying the width of a slab cast in a continuous-casting mould
US06/883,395 US4727926A (en) 1984-11-09 1986-07-29 Apparatus for changing width of slab in continuous casting

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10950885A JPS61266166A (en) 1985-05-21 1985-05-21 Method for changing ingot width

Publications (2)

Publication Number Publication Date
JPS61266166A JPS61266166A (en) 1986-11-25
JPH0557066B2 true JPH0557066B2 (en) 1993-08-23

Family

ID=14512040

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10950885A Granted JPS61266166A (en) 1984-11-09 1985-05-21 Method for changing ingot width

Country Status (1)

Country Link
JP (1) JPS61266166A (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104942250B (en) * 2014-03-26 2017-08-11 上海宝信软件股份有限公司 The method of continuous casting billet online presetting wide setting and tracking
KR101714850B1 (en) * 2014-12-24 2017-03-10 주식회사 포스코 Apparatus for Continuous Casting

Also Published As

Publication number Publication date
JPS61266166A (en) 1986-11-25

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