JP4309501B2 - Rolling method for cold tandem rolling mill - Google Patents

Description

したがって、ロールバイト出口の温度Ｔ_O は、式（１）を整理することによって式（２）で表わされる。
【数２】

ここで、Ｔ_w ：板冷却装置の冷却水温度
Ｔ_S ：板温度検出位置での板温度
Ｖ_O ：圧延機出側の板速度
ｈ ：圧延機出側の板厚
ρ_S ：板の密度
Ｃ_S ：板の比熱
ｈ_S ：板の熱伝達率
ｔ₁ ：板冷却装置から水切り装置までの距離を板が通過する時間
（ｔ₁ ＝Ｌ₁ ／Ｖ_O ）
Ｌ₁ ：板冷却装置から水切り装置までの距離
である。板の熱伝達率ｈ_S は実験を行って、冷却水量（単位時間単位面積当たりの冷却水供給量）との関係をあらかじめモデル化する必要がある。式（３）は、所要のパラメーターを含む熱伝達率モデル式の一般形を示している。
【数３】

Ｑ_w ：冷却水の供給量
Ｗ ：板幅
【００２１】
なお、空冷の場合、空冷時間が約０．５秒以内（圧延速度約５００m/min 以上）では、空冷による温度変化は無視できる。したがって、前段スタンドの出側板温度は、そのまま板温度検出位置の板温度とみなすことができる。
【００２２】
上記温度データに基づいて定常状態でのロールバイト出口板温度を推定する。例えば、潤滑条件の制御周期（ヒートスクラッチを防止するための潤滑油濃度および／または潤滑油供給量の制御周期）を１分と設定し、過去１分間の板温度のデータ（この場合１２個、ただし潤滑条件は一定であるもののデータ）を用いて、最終的には一定値に漸近する漸近曲線を表す関数に代入し、重回帰を行うことによってその関数の定数を決定し、その漸近値を定常状態におけるロールバイト出口板温度の推定値Ｔ_f とする。このような最終的には一定値に近づく漸近曲線を表す関数としては、例えばａ・tanh (ｃＸ）やａ＋ｂ（１−ｅ^-cx ）等がある。この関数で、ａ、ｂ、ｃは定数であり、最終的にはそれぞれａおよびａ＋ｂに漸近する。したがって、このような関数に測定した温度データを代入し、それぞれの漸近値ａあるいはａ＋ｂを求め、これを定常状態の板温度の推定値Ｔ_f とする。
【００２３】
また、このような方法の他に、例えば潤滑の制御周期（ヒートスクラッチを防止するための潤滑油濃度および／または潤滑油供給量の制御周期）を例えば３０秒と設定し、この制御周期である３０秒間に得られた６個の温度データを直線回帰し、次の潤滑の制御タイミング（次の潤滑制御時期）となる３０秒後の板温度を推定して板温度の推定値Ｔ_f としてもよい。
【００２４】
つぎに、ヒートスクラッチ制御温度の設定について説明する。あらかじめワークロール速度、圧下率、圧延潤滑条件等を変えた実験によって、ヒートスクラッチが発生する最低のロールバイト出口板温度を求め、これを限界温度Ｔ_Lim とする。この限界温度を、ヒートスクラッチ制御目標温度Ｔ_L としてもよいが、このヒートスクラッチ制御目標温度Ｔ_L は前述した限界温度Ｔ_Lim よりも若干低い温度、例えば３〜６℃程度低い温度に設定することが好ましい。
【００２５】
このようにヒートスクラッチが発生しやすいスタンド、図１では第４スタンドにおいて、ロールバイト出口の板温度の推定値Ｔ_f と前述したヒートスクラッチ制御目標温度Ｔ_L とを比較する。ΔＴ＝Ｔ_L −Ｔ_f が正の場合には、ヒートスクラッチは生じる可能性はないので圧延をそのまま続行する。ΔＴ＝Ｔ_L −Ｔ_f が負の値の場合には、ヒートスクラッチが生じる可能性があるので、ΔＴが正となるように潤滑条件（潤滑油の濃度および／または供給量）を変更して圧延を行う。
【００２６】
以下に変更する潤滑油濃度および潤滑油供給量の計算方法について説明する。まず、圧延中の摩擦係数μと変形抵抗Ｋ_m を求める。圧延材の変形抵抗はあらかじめ引張試験によって式（４）に示す定数ａ、ε₀ 、ｎの値を求めておく。
【数４】

ここで、σ_y は圧延材の単純引張時の降伏応力であり、εはひずみである。
【００２７】
ところで、変形抵抗はひずみ速度の影響や板温度の影響を受けるので、式（４）から求められた変形抵抗Ｋ_ｍは必ずしも圧延時の正確な値ではない。そこで、この発明では、圧延荷重式および先進率式を連立させ、圧延時の変形抵抗と摩擦係数を求める。例えば、Ｈｉｌｌの荷重式を式（５）に示すように変形抵抗Ｋ_ｍについて展解して、変形抵抗Ｋ_ｍを求める。また、Ｂｌａｎｄ ＆ Ｆｏｒｄの先進率式を式（６）に示すように摩擦係数μ_Ｅについて展解し、式（５）で求めた変形抵抗Ｋ_ｍを式（６）に代入して摩擦係数μ_Ｅを求める。式（５）および（６）中で添字Ｅは当該スタンドの圧延時における検出値および検出値に基づく計算値である。計算値は、先に述べたようにロードセルで検出した前張力を板断面積で割る、ロードセルで検出した圧延荷重からベンディング力を除外するなどして求めた値である。
【数５】

【数６】

【００２８】
上式で未知数は摩擦係数μ_E と変形抵抗式Ｋ_mEの中の定数（式（４）中のａ）の２個であり、他は既知数で方程式数は２個である。したがって、この方程式は解くことができる。なお、演算に当たっては、摩擦係数μ_E の初期値として０．０５程度が、また変形抵抗式中の定数ａの初期値として引張試験によって求められた値がそれぞれ使われることが好ましい。
【００２９】
一方、この時のロールバイト出口のロールと圧延材との界面の上昇温度Ｔ′は、例えば小野らの式を用いれば式（７）で表される。
【数７】

【００３０】
Ｔ_ｄｍａｘは変形熱により増加するロールと圧延材との界面のロールバイト出口の温度上昇であり、式（９）で表される。Ｔｆｍａｘは摩擦熱により増加する界面のロールバイト出口の温度上昇であり、式（８）で表される。
【数８】

【数９】

【００３１】
式（８）、（９）にそれぞれの当該スタンドの物性値および実測値、ならびに前述した式（５）、（６）を用いる方法で求められた摩擦係数μ_E および変形抵抗Ｋ_mEを代入すれば、当該スタンドのロールバイト出口のロールと圧延材の界面の温度上昇Ｔ′の計算値Ｔ _E ′が求まる。
【００３２】
つぎに、潤滑条件（潤滑油の濃度および／または供給量）を変えた場合の温度変化を推定する。このために、摩擦係数μ以外は当該スタンドの実測値を用い、潤滑条件だけを変えた場合の圧延荷重Ｐと先進率ｆs を計算する。
【００３３】
圧延荷重Ｐは例えば式（１０）に示す Hill の荷重式を用い、先進率ｆs は式（１１）に示す Hland & Ford の式を用いてそれぞれ計算する。ロール偏平Ｒ′は、式（１２）に示すHitchcook の式を用いて計算する。
【数１０】

【数１１】

【数１２】

【００３４】
上記式（１０）、（１１）中の摩擦係数μは次のようにして定める。
まず、潤滑状態を良くした場合（ストリップ単位面積当たりの供給量や油の濃度を増大した場合）の摩擦係数μ′を式（１３）により求める。
【数１３】

式（１３）中の圧延中の摩擦係数μ_Ｅは、前述のように式（５）、（６）から求めた値である。また、一般に摩擦係数μは式（１４）で表される。
【数１４】

α、β、γはロール粗度等の変化に応じ変化する係数であり、制御周期毎に求める。求め方は式（１４）と上記摩擦係数μ_Ｅから計算により簡単に求まる。
ただし、濃度を変えずに流量のみ変える場合、β＝γ＝０
流量を変えずに濃度のみ変える場合、α＝γ＝０
流量と濃度を変える場合、α＝β＝０
とする。
現在の供給量Ｑ_ｏと濃度Ｃ_Ｌｏとし、濃度を変えずに供給量のみＱ_ｏ′に変える場合、β＝γ＝０とする。その際の摩擦係数の変化Δμは
【数１５】

流量を変えずに濃度のみＣ_Ｌｏ′に変える場合、α＝γ＝０とする。その際の摩擦係数の変化Δμは
【数１６】

また、流量をＱ_ｏ′と濃度をＣ_Ｌｏ′に変える場合、α＝β＝０とする。その際の摩擦係数の変化Δμは
【数１７】

α _ｏ 、β _ｏ 、γ _ｏ は定数であり、実験により予め求める。
【００３５】
このようにして求めた摩擦係数の変化Δμを式（１３）に代入して、潤滑条件を変化したときの摩擦係数μ′を求める。なお、潤滑油の供給量を変えるには、例えばポンプの回転数を調整する。潤滑油の濃度は、スタティックミキサー、タンクの切替え等により変えるなどの方法がある。
【００３６】
求めた摩擦係数μ′を式（１０）の摩擦係数μに代入し、式（１０）とロール偏平の式（１２）とを用いて収束計算を行うことにより圧延荷重Ｐが求められる。式（１１）より先進率ｆ_ｓが求まる。これら圧延荷重Ｐおよび先進率ｆ_ｓ、ならびに上記摩擦係数μ′を、式（８）に用いることによりＴ _ｆｍａｘ が求まり、式（９）に用いることによりＴ _ｄｍａｘ が求まる。したがって、式（７）により、潤滑条件を変更した際のロールバイト出口の界面の温度上昇Ｔ_ｍ′が求まる。すなわち、上記の当該スタンドでのロールバイト出口の界面温度上昇の計算値Ｔ _E ′と、潤滑条件を変更したときのロールバイト出口の温度上昇の推定値Ｔ_ｍ′が得られる。ロールバイト出口におけるロールと圧延材の界面の温度とスタンド出側における板温度とは厳密には同じではないが、潤滑条件を変化させた場合の温度変化は同じであるとみなしてよい。したがって、このＴ_ｍ′とＴ_Ｅ′との差（ΔＴ′＝Ｔ_ｍ′−Ｔ_Ｅ′）と、先に述べたＴ_ＬとＴ_ｆとの差（ΔＴ＝Ｔ_Ｌ−Ｔ_ｆ）とを比べて、ΔＴ′がΔＴ以下（ΔＴ′≦ΔＴ）となるような潤滑条件（潤滑油の濃度および／または供給量）を、例えばニュートン法などを用いて繰り返し計算によって求めることができる。当該圧延機の潤滑条件設定値を、上記のようにして得られた潤滑油の濃度および／または供給量に変更する。上述の関係を満たすヒートスクラッチの発生しない潤滑条件をいくつか求めることができる。これら潤滑条件の中から適切な潤滑条件を圧延状況にあわせて選択すればよいが、最低の潤滑油濃度および／または供給量を選定し、これに従って当該スタンドの潤滑油濃度および／または供給量設定値を変更することが望ましい。
【００３７】
なお、これらの制御の際、圧延荷重の変化量があらかじめ予測できるので、板厚精度や板形状の不良が発生しないように板厚および形状制御を行うこともできる。
【００３８】
以上はヒートスクラッチを圧延機ロールバイト出口の板温度で制御する方法について示したが、潤滑油によってはロールバイト出口の温度ではなく、ロールバイト内での上昇温度で制御する方がよい場合もある。この場合には、圧延機入側でも板の温度Ｔｉを温度検出器によって検出する。温度検出器から圧延機入側までに水冷していない場合で、圧延速度５００m/min 以上ではたとえ潤滑油が板表面にかかったとしてもロールバイト入口の板温度に及ぼすそれらの影響は無視できる。したがって、前述のＴ_O の代わりにＴ_O ′＝Ｔ_O −Ｔｉを用いて同様にやればよい。その際、Ｔ_f をΔＴ_f に、Ｔ_L をΔＴ_L としてやればよい。
【００３９】
【実施例】
使用した冷間タンデム圧延機は図１に示したものと同じ５スタンドからなるタンデム圧延機であり、ヒートスクラッチが発生するスタンドとしての第４スタンドの圧延条件を表１に示す。
【表１】

【００４０】
操業条件において、同一サイズのコイルを同一の圧延条件で大量に圧延して行くと、ワークロールの平均温度が上昇し、第４スタンド出側の板温度が上昇して行く。これまでの操業データから、第４スタンド出側の板温度が約１６０℃以上であると、ヒートスクラッチが多発することが経験的に知られている。そこで、この発明を適用し、その効果を実験調査した。
【００４１】
あらかじめ実験によって求められたヒートスクラッチが発生する最低のロールバイト出口板温度である限界温度Ｔ_Lim は１６２℃であり、ヒートスクラッチ制御目標温度はＴ_L ＝１６２−４＝１５８℃とした。また、潤滑油濃度の制御周期を３０秒、サンプリング時間を５秒とし、その間の３０秒（６個）のデータからロールバイト出口の板温度を計算・直線回帰し、３０秒後のロールバイト出口板温度を求めてこれを板温度の推定値Ｔ_f とした。なお、潤滑油はパーム油であり、設定濃度は１５％である。
【００４２】
図３は第２の発明による効果を示す図であり、図３中の○は従来の圧延方法の場合を、●は本発明を適用した際の場合をそれぞれ示す。図３（ａ）は、圧延コイル本数と第４スタンドロールバイト出口の板温度との関係を示す。従来の圧延方法ではコイル本数１１本目でロールバイト出口板温度の推定値は１６０℃以上となり、ヒートスクラッチが発生する危険があるので、図３（ｂ）に示すようにワークロール速度を９００m・min ^-1にまで減速して操業していた。これに対し、この発明では図３（ｃ）に示すように潤滑油濃度をロールバイト出口予測温度に基づき変更した。その結果、コイル本数３０本でも板温度は１５８℃以上になることはなかった。また、ワークロール速度を１２００m・min ^-1に維持したままで圧延し、当然のことながらヒートスクラッチも発生しなかった。
【００４３】
第３スタンドの板冷却条件を大幅に変えた場合、精度が悪化したので、第３の発明を適用した。すなわち、あらかじめ実験によって求められたヒートスクラッチが発生するロールバイト上昇温度である限界温度Ｔ_Lim は１０８℃であり、ヒートスクラッチ制御目標温度はＴ_L ＝１０８−４＝１０４℃とした。また、潤滑油濃度の制御周期を３０秒、サンプリング時間を５秒とし、その間の３０秒（６個）のデータからロールバイト上昇温度を計算・直線回帰し、３０秒後のロールバイト上昇温度を求めてこれを板温度の推定値Ｔ_f とした。この結果、第３スタンドの板冷却条件を大幅に変えても、ヒートスクラッチは発生しなかった。
【００４４】
【発明の効果】
ロールバイト内温度をヒートスクラッチが発生しない温度以下に維持することができるので、生産性を阻害せずにヒートスクラッチの発生を防止することができる。
【図面の簡単な説明】
【図１】この発明を実施する冷間タンデム圧延機の一例を示す構成図である。
【図２】冷間タンデム圧延機中の２スタンドの拡大図である。
【図３】（ａ）は圧延材のロールバイト出口温度と圧延コイル本数との関係、（ｂ）はワークロール速度と圧延コイル本数との関係、および（ｃ）は潤滑油濃度と圧延コイル本数との関係をそれぞれ示すグラフである。
【符号の説明】
１１ ワークロール
１３ 中間ロール
１５ バックアップロール
１７ 板厚検出器
２０ 板冷却装置
２２ 水切り兼張力検出装置
２４ 温度検出器
２６ 潤滑油供給装置
Ｓ 圧延材（板）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling method for preventing the occurrence of heat scratch without impairing productivity in a cold tandem rolling mill having a plurality of cold rolling mills.
[0002]
[Prior art]
In a cold tandem rolling mill, heat scratches may occur due to an increase in work roll speed or rolling reduction. A heat scratch is a seizure flaw generated by metal contact between a work roll and a rolled material as a result of an increase in the interface temperature between the roll and the rolled material in the roll bite and an oil film breaking in the roll bite. .
[0003]
When the heat scratch occurs, the surface defect of the product occurs, so that not only the product yield is lowered, but also the work roll of the stand where the heat scratch is generated needs to be changed, so that the productivity is remarkably lowered.
[0004]
The presence or absence of the occurrence of heat scratch can be predicted by the interface rising temperature in the roll bite during rolling. In actual operation, although the rolling schedule differs depending on the steel type, the same steel type is rolled under substantially the same rolling conditions (hereinafter also including cooling conditions), so the interface rising temperature can be substituted by the plate temperature on the stand exit side. Therefore, control is performed so that the plate temperature on the delivery side of the rolling mill is detected and the plate temperature is equal to or lower than the appropriate value based on the detected value.
[0005]
The above-described method of controlling the plate temperature on the stand exit side as the roll bite temperature is effective under almost the same rolling conditions (constant speed, coolant, etc.). For example, when cooling is not performed between the exit of the rolling mill roll bite and the plate temperature detector (air cooling), there is no significant problem. In the case of the i stand of FIG. 2, the upper and lower work rolls are cooled by the roll cooling device 30, but the cooling water is prevented from hitting the plate S by the draining device 32. Therefore, since the measurement value of the temperature detector 34 is not affected by roll cooling, it is possible to prevent i-stand heat scratching by the conventional technique.
[0006]
However, when cooling is performed between the exit of the rolling mill roll bite and the plate temperature detector (water cooling), it becomes a big problem. For example, in the case of (i-1) stand of FIG. 2, the plate S is cooled by the plate cooling device 20 on the exit side of the rolling mill, and the cooling water remains on the surface. The remaining cooling water is drained by the draining and tension detecting device 22, and then the temperature is measured by the temperature detector 24. Therefore, the influence of the plate cooling device 20 on the temperature detector 24 is large. Even if the amount of cooling water is the same, the temperature of the cooling water is affected. The water temperature is about 20 ° C in the summer and about 5 ° C in the winter. The heat scratch control target temperature T of the conventional control is empirically in the summer and winter._LNeeded to be held at the table according to the water temperature. Also, this heat scratch control target temperature T_LBecause it is necessary to confirm by experiment, the setting was a problem. Further, when the amount of water in the plate cooling device 20 is significantly changed, there is a problem that the influence of the amount of water cannot be ignored. Depending on the lubricant used, the accuracy may be improved by controlling the interface rise temperature (the temperature difference between the plates on the entrance and exit of the rolling mill) rather than controlling the plate surface temperature (maximum temperature).
[0007]
Regarding heat scratch prevention, for example, as disclosed in Japanese Patent Laid-Open No. 5-98283, a method using a rolling lubricant having excellent seizure resistance, or as disclosed in Japanese Patent Laid-Open No. 56-111505. In addition, there are a method for reducing the temperature of the plate and the work roll by controlling the amount of coolant, and a method for reducing the work roll speed as disclosed in Japanese Patent Laid-Open No. 6-63624. Both methods relate to a method of preventing an increase in the interface temperature between the work roll and the rolled material in the roll bite or preventing the oil film from breaking even if the interface temperature in the roll bite increases. However, the use of rolling lubricants with excellent seizure resistance may increase costs, and although the plate and roll temperature control by controlling the coolant amount is effective, there are some problems with its responsiveness. The decrease in the roll speed has a problem that the productivity decreases.
[0008]
As a method for preventing heat scratching without causing a decrease in productivity and an increase in manufacturing cost, Japanese Patent Laid-Open No. 60-49802 discloses changing the rolling schedule and tension, It is not clear how to predict the occurrence in advance and how to determine the amount of control.
[0009]
[Problems to be solved by the invention]
As a method for preventing heat scratching without causing a decrease in productivity and an increase in manufacturing cost as described above, there is a problem that the plate thickness accuracy is temporarily deteriorated when the reduction schedule is changed. Also, when changing the tension, naturally, if it is set to a high value, the rolling load is reduced and the effect of preventing heat scratching can be obtained. However, if the tension is increased, the plate may break, and gradually while watching the rolling situation. When the tension is increased, the responsiveness deteriorates, and there is a problem that heat scratches occur and the plate thickness accuracy deteriorates. Further, when the plate temperature on the stand exit side is detected and the tension is controlled based on the temperature, the control is performed when the temperature becomes higher than the temperature at which the heat scratch occurs, so that the heat scratch is temporarily generated. There is a risk.
[0010]
This invention makes it a subject to provide the rolling method in a cold tandem rolling mill which prevents generation | occurrence | production of a heat scratch, without inhibiting productivity.
[0011]
[Means for Solving the Problems]
The gist of the present invention is as follows.
1) Cooling water of the plate cooling device installed between the detected value of the plate temperature, the plate thickness, and the plate speed on the stand exit side, or these detected values and the temperature detector that detects the plate surface temperature from the stand exit side. The roll bite outlet plate temperature is estimated based on the values of the temperature and the cooling water supply amount, and the lubricating oil concentration and / or the lubricating oil supply amount are controlled based on this value.
2) The plate cooling installed between the stand entry / exit plate temperature, stand exit plate speed and stand exit plate thickness detection values, or these detection values and the temperature detector that detects the plate surface temperature from the rolling mill exit side. The plate rising temperature in the roll bite is estimated based on the detected values of the coolant temperature and flow rate of the apparatus, and the lubricating oil concentration and / or lubricating oil supply amount is controlled based on these values.
[0012]
  This invention is based on the above summary,
  The rolling method in the cold tandem rolling mill according to the first aspect of the invention is a rolling method in a cold tandem rolling mill in which a stand where heat scratches are likely to occur is designated in advance and rolling is performed by the following steps on the designated stand.
(B) First step of detecting stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, lubricant concentration, and lubricant supply amount, respectively.
(B) The plate temperature is estimated a plurality of times from the detected values of the plate temperature, the plate thickness, and the plate speed on the exit side of the stand, and the roll bite outlet plate temperature T in the rolled state based on the estimated plate temperature data._fSecond step of estimating
(C) Roll bite exit estimated plate temperature T_fPreset heat scratch control target temperature T_LThe first step of rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, and stand entry / exit side tension detection values to determine the friction coefficient and deformation resistance of the rolled material. 3 steps
(D)Detection value of the first step,In addition, the friction coefficient and deformation resistance obtained in the third stepThe plate temperature rise T in the roll bite in the rolled state due to_E ′When the lubricant concentration and / or lubricant supply amount is changedThe friction coefficient μ ′ is obtained, the detected value in the first step, the friction coefficient μ ′, and the deformation resistance obtained in the third step.UsingWhen the lubricant concentration and / or lubricant supply amount is changedRoll bite inner plate temperature rise T_m′ For T_L-T_f≧ T_m'-T_EThe fourth step for determining the lubricant concentration and / or the lubricant supply amount to be '
(E) Fifth step of controlling the lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount obtained in the fourth step as target values
(F) Sixth step of controlling the plate thickness and shape corresponding to the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step is changed.
[0013]
  The rolling method in the cold tandem rolling mill of the second aspect of the invention designates in advance a stand where heat scratches are likely to occur, and while performing plate cooling (water cooling) between the plate temperature detectors from the rolling mill roll bite exit side, A rolling method in a cold tandem rolling mill that performs rolling in the designated step according to the next step.
(B) Stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, plate cooling water temperature, plate cooling water supply amount, lubricant concentration, and First step of detecting the amount of lubricant supply
(B) The plate temperature is estimated a plurality of times from the detected values of the plate temperature, the plate thickness, the plate speed, the plate cooling water temperature and the plate cooling water supply amount at the stand exit side, and the estimated plate temperature data Based on the above, the roll bite outlet plate temperature T in the rolled state_fSecond step of estimating
(C) Roll bite exit estimated plate temperature T_fPreset heat scratch control target temperature T_LThe first step of rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, and stand entry / exit side tension detection values to determine the friction coefficient and deformation resistance of the rolled material. 3 steps
(D)Detection value of the first step,In addition, the friction coefficient and deformation resistance obtained in the third stepThe plate temperature rise T in the roll bite in the rolled state due to_E ′When the lubricant concentration and / or lubricant supply amount is changedThe friction coefficient μ ′ is obtained, the detected value in the first step, the friction coefficient μ ′, and the deformation resistance obtained in the third step.UsingWhen the lubricant concentration and / or lubricant supply amount is changedRoll bite inner plate temperature rise T_m′ For T_L-T_f≧ T_m'-T_EThe fourth step for determining the lubricant concentration and / or the lubricant supply amount to be '
(E) Fifth step of controlling the lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount obtained in the fourth step as target values
(F) Sixth step of controlling the plate thickness and shape corresponding to the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step is changed.
[0014]
  The rolling method in the cold tandem rolling mill according to the third aspect of the invention is a rolling method in a cold tandem rolling mill in which a stand where heat scratches are likely to occur is designated in advance, and rolling is performed by the following steps on the designated stand.
(B) Stand entry side plate temperature, stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, lubricant concentration, and lubricant supply amount First step to detect
(B) From the detected values of the stand exit side plate temperature, stand exit side plate speed, and stand exit side plate thickness, the plate temperature is estimated a plurality of times, and based on the estimated plate temperature data, the roll bite exit plate in the rolled state Temperature T_fSeeking T_fThe temperature rise in the roll bite in the rolled state by subtracting the stand entry side plate temperature from ΔT_fSecond step to find
(C) Estimated rising temperature ΔT in the roll tool_fPreset heat scratch control target temperature ΔT_LThe first step of rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, and stand entry / exit side tension detection values to determine the friction coefficient and deformation resistance of the rolled material. 3 steps
(D)Detection value of the first step,In addition, the friction coefficient and deformation resistance obtained in the third stepThe plate temperature rise T in the roll bite in the rolled state due to_E ′When the lubricant concentration and / or lubricant supply amount is changedThe friction coefficient μ ′ is obtained, the detected value in the first step, the friction coefficient μ ′, and the deformation resistance obtained in the third step.UsingWhen the lubricant concentration and / or lubricant supply amount is changedRoll bite inner plate temperature rise T_m′ And ΔT_L-ΔT_f≧ T_m'-T_EThe fourth step for determining the lubricant concentration and / or the lubricant supply amount to be '
(E) Fifth step of controlling the lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount obtained in the fourth step as target values
(F) Sixth step of controlling the plate thickness and shape corresponding to the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step is changed.
[0015]
  The rolling method in the cold tandem rolling mill of the fourth aspect of the invention designates in advance a stand where heat scratches are likely to occur, while performing plate cooling (water cooling) between the plate temperature detectors from the rolling mill roll bite exit side, A rolling method in a cold tandem rolling mill that performs rolling in the designated step according to the next step.
(B) Stand entry side plate temperature, stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit plate thickness, stand entry / exit side tension, lubricant concentration, lubricant supply amount, plate cooling First step of detecting water temperature and plate cooling water supply amount, respectively
(B) The plate temperature is estimated several times from the detected values of the stand exit side plate temperature, stand exit side plate speed, stand exit side plate thickness, plate cooling water temperature, and plate cooling water supply amount, and the estimated plate temperature Based on the data, the roll bite outlet plate temperature T in the rolled state_fSeeking T_fThe temperature rise in the roll bite in the rolled state by subtracting the stand entry side plate temperature from ΔT_fSecond step to find
(C) Estimated rising temperature ΔT in the roll tool_fPreset heat scratch control target temperature ΔT_LThe first step of rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, and stand entry / exit side tension detection values to determine the friction coefficient and deformation resistance of the rolled material. 3 steps
(D)Detection value of the first step,In addition, the friction coefficient and deformation resistance obtained in the third stepThe plate temperature rise T in the roll bite in the rolled state due to_E ′When the lubricant concentration and / or lubricant supply amount is changedThe friction coefficient μ ′ is obtained, the detected value in the first step, the friction coefficient μ ′, and the deformation resistance obtained in the third step.UsingWhen the lubricant concentration and / or lubricant supply amount is changedRoll bite inner plate temperature rise T_m′ And ΔT_L-ΔT_f≧ T_m'-T_EThe fourth step for determining the lubricant concentration and / or the lubricant supply amount to be '
(E) Fifth step of controlling the lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount obtained in the fourth step as target values
(F) Sixth step of controlling the plate thickness and shape corresponding to the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step is changed.
[0016]
In these inventions, the plate cooling device installed between the rolling mill delivery side plate temperature, the rolling load, etc., or between these detection values and the temperature detector that further detects the plate surface temperature from the rolling mill delivery side. The temperature and flow rate of the cooling water are detected, and the friction coefficient and deformation resistance are obtained based on these detected values. Then, the roll bite outlet temperature or the roll bite entry / exit temperature is obtained, and the lubricant concentration and / or the lubricant supply amount are controlled so that these do not exceed the heat scratch control target temperature. Therefore, the temperature inside the roll bite can be maintained below the temperature at which heat scratches do not occur.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of a cold tandem rolling mill in which the rolling method of the present invention is implemented. Although the number of stands of the cold tandem rolling mill is usually 2 to 8, and 5 stands are shown in FIG. 1, the number of stands is not limited to this. The stands 1 to 5 are each composed of a work roll 11, an intermediate roll 13, and a backup roll 15. The stands where heat scratches are likely to occur vary depending on the reduction ratio, plate thickness, rolling load, tension, rolling material, lubrication conditions, etc. of each stand. Usually, heat scratches tend to occur at a later stage stand where the rolling load and work roll speed increase. In the cold tandem rolling mill of FIG. 1, the fourth stand 4 is in a state where heat scratches frequently occur because the final stand 5 is under light rolling dull rolling. In the case where there is a possibility that heat scratches may occur in a stand other than the subsequent stand, the present invention can be applied to those stands. A lubricating oil supply device 26 is disposed on the entry side of each stand. The final stand 5 includes a work roll cooling device 30 and a roll cooling drainer 32.
[0018]
In FIG. 1, a temperature detector 24 is provided after the draining and tension detecting device on the entrance side and the exit side of the rolling stand of the fourth stand 4 so that the plate temperature T of the plate S being rolled is detected at a constant cycle. ing. The temperature detector 24 is preferably a non-contact type, for example, a radiation thermometer. The rolling load P of the fourth stand 4 is detected by a load cell (not shown). Tension on the entry side and exit side of the rolling mill (force per unit area) σ_b, Σ_fIs obtained by dividing the total tension by the plate cross-sectional area (plate thickness / plate width). The total tension is detected by a load cell (not shown) of the draining / tension detecting device 22 provided on the inlet side and the outlet side of the rolling mill. A plate thickness measuring device 17 such as an X-ray plate thickness meter is provided on the entry side and the exit side of the fourth stand 4, and a plate speedometer (not shown) is provided on the exit side of the fourth stand 4 and the third stand 3. ), For example, a laser plate speedometer is provided. With these measuring instruments, the inlet and outlet plate thicknesses H and h of the fourth stand 4 and the inlet and outlet plate speeds V_I, V_OAre detected respectively. Work roll speed V of the fourth stand 4_RIs obtained by detecting the number of revolutions of the motor that drives the work roll 11 with a revolution number detection device (not shown) and calculating using the detected number of revolutions of the motor, the work roll diameter D, and the gear ratio. . Further, the plate S is cooled by the plate cooling device 20 on the entrance side and the exit side of the fourth stand.
[0019]
In the cold tandem rolling mill, the work roll diameter D, the roll drive system gear ratio, the plate width W, the material plate thickness (H_S: Thickness on the entrance side of the first stand 1), and yield stress σ during simple tension of the material_yIs known and can be input in advance to a calculator (not shown). The rolling load of the present invention is a load required for plastic deformation of the material, and when the stand has a shape control device such as a bender, those forces were detected and obtained by the load cell described above. This means the load excluding the force of the bender etc. from the load.
[0020]
Next, a plate temperature estimation method will be described. The plate temperature detector 24 provided on the exit side of the rolling mill detects the plate temperature on the exit side of the rolling mill at a constant period τ (for example, 5 s), and the plate temperature T at the exit of the rolling mill roll bite._OIs estimated.
Plate temperature T when water cooling is generally performed_SIs given by equation (1).
[Expression 1]

Therefore, the temperature T of the roll bite outlet_OIs expressed by equation (2) by rearranging equation (1).
[Expression 2]

Where T_w: Cooling water temperature of plate cooling device
T_S: Plate temperature at the plate temperature detection position
V_O: Plate speed on the exit side of the rolling mill
h: Thickness on the exit side of the rolling mill
ρ_S: Plate density
C_S: Specific heat of the plate
h_S: Heat transfer coefficient of plate
t₁: Time for the plate to pass the distance from the plate cooling device to the draining device
(T₁= L₁/ V_O)
L₁: Distance from plate cooling device to draining device
It is. Heat transfer coefficient h_SIt is necessary to model in advance the relationship with the amount of cooling water (the amount of cooling water supplied per unit time unit area) by conducting an experiment. Expression (3) shows a general form of a heat transfer coefficient model expression including necessary parameters.
[Equation 3]

Q_w: Supply amount of cooling water
W: Plate width
[0021]
In the case of air cooling, a temperature change due to air cooling can be ignored if the air cooling time is within about 0.5 seconds (rolling speed of about 500 m / min or more). Therefore, the exit side plate temperature of the front stand can be regarded as the plate temperature at the plate temperature detection position as it is.
[0022]
A roll bite outlet plate temperature in a steady state is estimated based on the temperature data. For example, the control cycle of the lubrication condition (the control cycle of the lubricating oil concentration and / or the lubricating oil supply amount for preventing heat scratch) is set to 1 minute, and the plate temperature data for the past 1 minute (in this case, 12 pieces, However, the data of the lubrication condition is constant), and finally it is substituted into a function that represents an asymptotic curve that asymptotically approaches a constant value. Estimated value T of roll bite outlet plate temperature in steady state_fAnd As such a function that represents an asymptotic curve that finally approaches a constant value, for example, a · tanh (cX) or a + b (1-e^-cx) Etc. In this function, a, b, and c are constants, and asymptotically approach a and a + b, respectively. Therefore, the measured temperature data is substituted into such a function to obtain the respective asymptotic values a or a + b, which are calculated as the steady state plate temperature estimated values T._fAnd
[0023]
In addition to such a method, for example, the control cycle of lubrication (the control cycle of the lubricating oil concentration and / or lubricating oil supply amount for preventing heat scratching) is set to 30 seconds, for example, and this control cycle. Six temperature data obtained in 30 seconds are linearly regressed, and the plate temperature 30 seconds after the next lubrication control timing (next lubrication control timing) is estimated to estimate the plate temperature T_fIt is good.
[0024]
Next, the setting of the heat scratch control temperature will be described. The minimum roll bite outlet plate temperature at which heat scratching occurs is obtained by experiments in which the work roll speed, rolling reduction, rolling lubrication conditions, etc. are changed in advance, and this is determined as the limit temperature T_LimAnd This limit temperature is set as the heat scratch control target temperature T._LThe heat scratch control target temperature T may be_LIs the above-mentioned limit temperature T_LimIt is preferable to set the temperature slightly lower than that, for example, about 3 to 6 ° C.
[0025]
The estimated value T of the plate temperature at the roll bite outlet in the stand where heat scratch is likely to occur, in FIG._fAnd the above-mentioned heat scratch control target temperature T_LAnd compare. ΔT = T_L-T_fIf is positive, there is no possibility of heat scratching, so rolling continues. ΔT = T_L-T_fWhen is a negative value, heat scratching may occur, and therefore rolling is performed by changing the lubricating conditions (concentration and / or supply amount of lubricating oil) so that ΔT becomes positive.
[0026]
A method for calculating the lubricating oil concentration and the lubricating oil supply amount to be changed will be described below. First, friction coefficient μ and deformation resistance K during rolling_mAsk for. The deformation resistance of the rolled material is determined by constants a and ε shown in Equation (4) by a tensile test in advance.₀, N is obtained in advance.
[Expression 4]

Where σ_yIs the yield stress during simple tension of the rolled material, and ε is the strain.
[0027]
  By the way, since the deformation resistance is affected by the strain rate and the plate temperature, the deformation resistance K obtained from the equation (4)._mIs not necessarily an accurate value during rolling. Therefore, in the present invention, the rolling load equation and the advanced rate equation are combined to determine the deformation resistance and the friction coefficient during rolling. For example, as shown in Formula (5), Hill's load equation is a deformation resistance K_mUnfolding about deformation resistance K_mAsk for. In addition, as shown in Formula (6), the coefficient of friction μ_EDeformation resistance K obtained from equation (5)_mIs substituted into equation (6) and the friction coefficient μ_EAsk for. In equations (5) and (6), the subscript E is based on the detected value and the detected value when the stand is rolled.CalculationValueThe CalculationThe value is a value obtained by dividing the pre-tension detected by the load cell by the plate cross-sectional area as described above, or excluding the bending force from the rolling load detected by the load cell.
[Equation 5]

[Formula 6]

[0028]
In the above equation, the unknown is the friction coefficient μ_EAnd deformation resistance formula K_mEAre two constants (a in equation (4)), the other are known numbers, and the number of equations is two. Therefore, this equation can be solved. In the calculation, the friction coefficient μ_EIt is preferable that about 0.05 is used as the initial value of the value, and a value obtained by the tensile test is used as the initial value of the constant a in the deformation resistance equation.
[0029]
On the other hand, the rising temperature T ′ at the interface between the roll at the exit of the roll bite and the rolled material at this time is expressed by, for example, Expression (7) using the expression of Ono et al.
[Expression 7]

[0030]
  T_dmaxIs the temperature rise at the exit of the roll bite at the interface between the roll and the rolled material, which increases due to the heat of deformation.(9)It is represented by Tfmax is the temperature rise at the exit of the roll bite at the interface, which increases due to frictional heat.(8)It is represented by
[Equation 8]

[Equation 9]

[0031]
  The friction coefficient μ determined by the method using the physical property values and the actual measurement values of the respective stands in the formulas (8) and (9), and the formulas (5) and (6) described above._E And deformation resistance K_mEIs substituted for the temperature rise T ′ at the interface between the roll at the exit of the roll of the stand and the rolled material.Calculated value T _E ′Is obtained.
[0032]
Next, a change in temperature is estimated when the lubrication conditions (concentration and / or supply amount of lubricating oil) are changed. For this purpose, the rolling load P and the advance rate fs when only the lubrication conditions are changed are calculated using the measured values of the stand other than the friction coefficient μ.
[0033]
The rolling load P is calculated using, for example, Hill's load equation shown in Equation (10), and the advanced rate fs is calculated using the Hland & Ford equation shown in Equation (11). The roll flatness R ′ is calculated using the Hitchcook equation shown in equation (12).
[Expression 10]

## EQU11 ##

[Expression 12]

[0034]
  The friction coefficient μ in the above formulas (10) and (11) is determined as follows.
  First, the friction coefficient μ ′ when the lubrication state is improved (when the supply amount per strip unit area or the oil concentration is increased) is obtained by the equation (13).
[Formula 13]

Friction coefficient μ during rolling in formula (13)_EIs a value obtained from the equations (5) and (6) as described above. In general, the friction coefficient μ is expressed by the equation (14).
[Expression 14]

α, β, and γ are coefficients that change in accordance with changes in roll roughness and the like, and are obtained for each control cycle. The calculation method is the equation (14) and the friction coefficient μ_EEasy to calculate fromI want.
However, when only the flow rate is changed without changing the concentration, β = γ = 0
        When only the concentration is changed without changing the flow rate, α = γ = 0
        When changing the flow rate and concentration, α = β = 0
And
Current supply Q_oAnd concentration C_LoQ, only the supply amount without changing the concentration_oWhen changing to ′, β = γ = 0. Of the friction coefficientChange ΔμIs
[Expression 15]

Concentration only without changing flow rate C_LoWhen changing to ′, α = γ = 0To. The friction coefficient change Δμ at that time is
[Expression 16]

The flow rate is Q_o′ And concentration C_LoWhen changing to ′, α = β = 0. The friction coefficient change Δμ at that time is
[Expression 17]

α _o , Β _o , Γ _o Is a constant and is obtained in advance by experiments.
[0035]
The friction coefficient change Δμ thus determined is substituted into the equation (13) to determine the friction coefficient μ ′ when the lubrication conditions are changed. In order to change the supply amount of the lubricating oil, for example, the rotational speed of the pump is adjusted. There are methods such as changing the concentration of the lubricating oil by changing the static mixer or tank.
[0036]
  The rolling load P is obtained by substituting the obtained friction coefficient μ ′ into the friction coefficient μ in the equation (10) and performing convergence calculation using the equation (10) and the roll flatness equation (12). Advanced rate f from equation (11)_sIs obtained. These rolling load P and advanced rate f_sAnd the coefficient of friction μ ′Is used in equation (8) to obtain T _fmax Is obtained and used in the equation (9) to obtain T _dmax Is obtained.Therefore, according to the equation (7), the temperature rise T at the interface of the roll bite outlet when the lubrication condition is changed._m′ Is obtained. That is, the increase in the interface temperature of the roll bite outlet in the standCalculated value T _E ′And the estimated value T of the temperature rise at the roll bite outlet when the lubrication conditions are changed_m'Is obtained. Although the temperature at the interface between the roll and the rolled material at the exit of the roll tool and the plate temperature at the stand exit side are not strictly the same, the temperature change when the lubrication conditions are changed may be regarded as the same. Therefore, this T_m'And T_EDifference from ′ (ΔT ′ = T_m'-T_E′) And T mentioned above_LAnd T_f(ΔT = T_L-T_f), A lubricating condition (concentration and / or supply amount of lubricating oil) such that ΔT ′ is equal to or smaller than ΔT (ΔT ′ ≦ ΔT) can be obtained by repeated calculation using, for example, the Newton method. . The lubrication condition set value of the rolling mill is changed to the concentration and / or supply amount of the lubricating oil obtained as described above. Several lubrication conditions that do not generate heat scratches that satisfy the above relationship can be obtained. From these lubrication conditions, appropriate lubrication conditions can be selected according to the rolling conditions, but the minimum lubricating oil concentration and / or supply amount is selected and the lubricating oil concentration and / or supply amount of the stand is set accordingly. It is desirable to change the value.
[0037]
In addition, since the amount of change in the rolling load can be predicted in advance during these controls, the thickness and shape can be controlled so that the plate thickness accuracy and plate shape defects do not occur.
[0038]
The above shows the method of controlling the heat scratch by the plate temperature at the exit of the rolling mill roll bite. However, depending on the lubricating oil, it may be better to control at the temperature rising in the roll bite instead of the temperature at the exit of the roll bite. . In this case, the temperature Ti of the plate is detected by the temperature detector even on the inlet side of the rolling mill. In the case where the temperature is not cooled from the temperature detector to the entrance of the rolling mill, even if the lubricating oil is applied to the surface of the plate at a rolling speed of 500 m / min or more, their influence on the plate temperature at the roll bite inlet can be ignored. Therefore, the aforementioned T_OT instead of_O'= T_OWhat is necessary is just to do similarly using -Ti. At that time, T_fΔT_fAnd T_LΔT_LYou can do as.
[0039]
【Example】
The cold tandem rolling mill used is a tandem rolling mill having the same five stands as shown in FIG. 1. Table 1 shows the rolling conditions of the fourth stand as a stand where heat scratches occur.
[Table 1]

[0040]
Under the operating conditions, when a large number of coils of the same size are rolled under the same rolling conditions, the average temperature of the work roll rises and the plate temperature on the fourth stand outlet side rises. From the operation data so far, it is empirically known that heat scratches frequently occur when the plate temperature on the outlet side of the fourth stand is about 160 ° C. or higher. Then, this invention was applied and the effect was experimentally investigated.
[0041]
Limit temperature T, which is the lowest roll bite outlet plate temperature at which heat scratches determined in advance by experiment occur_LimIs 162 ° C. and the heat scratch control target temperature is T_L= 162-4 = 158 ° C. Also, the control period of the lubricant concentration is 30 seconds, the sampling time is 5 seconds, the plate temperature at the roll bite outlet is calculated from the data of 30 seconds (six) during that period, and linear regression is performed, and the roll bite exit after 30 seconds The plate temperature is obtained and this is estimated value T of the plate temperature._fIt was. The lubricating oil is palm oil, and the set concentration is 15%.
[0042]
FIG. 3 is a diagram showing the effect of the second invention. In FIG. 3, ○ indicates the case of the conventional rolling method, and ● indicates the case when the present invention is applied. FIG. 3A shows the relationship between the number of rolled coils and the plate temperature at the outlet of the fourth stand roll tool. In the conventional rolling method, the estimated value of the roll bite outlet plate temperature is 160 ° C. or more when the number of coils is eleven, and there is a danger of heat scratching. Therefore, as shown in FIG. 3B, the work roll speed is set to 900 m · min.^-1Slow down to the point of operation. On the other hand, in this invention, as shown in FIG.3 (c), lubricating oil density | concentration was changed based on roll bite exit | outlet temperature. As a result, the plate temperature did not exceed 158 ° C. even with 30 coils. The work roll speed is 1200m / min.^-1It was rolled while maintaining the same, and naturally no heat scratch was generated.
[0043]
Since the accuracy deteriorated when the plate cooling conditions of the third stand were significantly changed, the third invention was applied. That is, the limit temperature T, which is the roll bite rising temperature at which heat scratches determined in advance by experiment occur._LimIs 108 ° C. and the heat scratch control target temperature is T_L= 108−4 = 104 ° C. Also, the control cycle of the lubricant concentration is 30 seconds, the sampling time is 5 seconds, the roll bite rise temperature is calculated from the data of 30 seconds (six) during that period, and linear regression is performed, and the roll bite rise temperature after 30 seconds is calculated. Obtain this and estimate the plate temperature T_fIt was. As a result, no heat scratch was generated even when the plate cooling conditions of the third stand were significantly changed.
[0044]
【The invention's effect】
Since the temperature inside the roll bite can be maintained below the temperature at which heat scratches do not occur, the generation of heat scratches can be prevented without impairing productivity.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of a cold tandem rolling mill for carrying out the present invention.
FIG. 2 is an enlarged view of two stands in a cold tandem rolling mill.
3A is a relationship between a roll bite outlet temperature of a rolled material and the number of rolling coils, FIG. 3B is a relationship between a work roll speed and the number of rolling coils, and FIG. 3C is a lubricant concentration and the number of rolling coils. FIG.
[Explanation of symbols]
11 Work roll
13 Intermediate roll
15 Backup roll
17 Thickness detector
20 Plate cooling device
22 Draining and tension detector
24 Temperature detector
26 Lubricating oil supply device
S Rolled material (plate)

Claims (4)

A rolling method in a cold tandem rolling mill in which a stand where heat scratches are likely to occur is designated in advance and rolling is performed in the designated stand by the next step.
(B) First step of detecting stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, lubricant concentration, and lubricant supply amount, respectively. (B) The plate temperature is estimated a plurality of times from the detected values of the plate temperature, the plate thickness, and the plate speed on the stand exit side, and the roll bite outlet plate temperature T _f in the rolled state is based on the estimated plate temperature data. (C) When the roll bite outlet estimated plate temperature _Tf exceeds a preset heat scratch control target temperature _TL , the first step rolling load, work roll speed, stand exit side plate speed, stand third step of obtaining a friction coefficient and deformation resistance of the rolled material input and output side thickness, and the detected value of the stand entry-exit side tension (d) first stearate Detection values of the flops, and obtains the plate temperature increase T _E in the roll bite _'in the rolling state by the friction coefficient and deformation resistance obtained in the third step, when you change the lubricant concentration and / or lubricating oil supply amount And the lubricant concentration and / or the lubricant supply amount are changed using the detected value in the first step, the friction coefficient μ ′ and the deformation resistance obtained in the third step . Obtain the roll bite inner plate temperature rise T _m ′ and obtain the lubricating oil concentration and / or lubricating oil supply amount satisfying T _L −T _f ≧ T _m ′ −T _E ′ in the fourth step (e) and the fourth step. The lubricating oil concentration and / or lubricating oil supply determined in the fourth step (f) and (4) of controlling the lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount as a target value. Corresponding to the friction coefficient mu 'of changing the amount, the sixth step of performing plate thickness and shape control Cold tandem rolling, in which a stand that is prone to heat scratching is designated in advance, and rolling is performed in the designated stand by the following steps while performing plate cooling (water cooling) between the rolling mill roll bite and the plate temperature detector. Rolling method in the machine.
(B) Stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, plate cooling water temperature, plate cooling water supply amount, lubricant concentration, and First step (b) of detecting the lubricant supply amount respectively (b) The plate temperature is determined a plurality of times from the detected plate temperature, plate thickness and plate speed on the stand exit side, and the plate cooling water temperature and plate cooling water supply amount. The second step of estimating the roll bite outlet plate temperature _Tf in the rolling state based on the estimated plate temperature data (c) Heat scratch control target preset by the roll bite outlet estimated plate temperature _Tf if it exceeds the temperature T _L, the rolling load of the first step, the work roll speed, stand delivery side speed, thickness at delivery side of the stand incident and, and stand input and exit side tension The third step of obtaining a friction coefficient and deformation resistance of the rolled material from detection value (d) the detected value of the first step, and, the plate temperature rise in the roll bite in the rolling state by the friction coefficient and deformation resistance obtained in the third step _TE ′ is obtained, the friction coefficient μ ′ is obtained when the lubricating oil concentration and / or the lubricating oil supply amount is changed, and the detected value of the first step, the friction coefficient μ ′ and the third step are obtained. Lubricating oil satisfying T _L −T _f ≧ T _m ′ −T _E ′ by obtaining the roller bite inner plate temperature rise T _m ′ when the lubricating oil concentration and / or the lubricating oil supply amount are changed using deformation resistance. Fourth step for obtaining concentration and / or lubricating oil supply amount (e) Control of lubricating oil concentration and / or lubricating oil supply amount with the lubricating oil concentration and / or lubricating oil supply amount obtained in the fourth step as target values Sixth step of the fifth step (to) corresponds to the friction coefficient mu 'of changing the lubricating oil concentration and / or lubricating oil supply amount calculated by the fourth step, performs plate thickness and shape control that A rolling method in a cold tandem rolling mill in which a stand where heat scratches are likely to occur is designated in advance and rolling is performed in the designated stand by the next step.
(B) Stand entry side plate temperature, stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, stand entry / exit side tension, lubricant concentration, and lubricant supply amount First step to detect (b) From the detected values of the stand exit side plate temperature, stand exit side plate speed, and stand exit side plate thickness, the plate temperature is estimated a plurality of times, and the rolling state is based on the estimated plate temperature data seeking the roll bite outlet plate temperature T _f in, T _f from the estimated increase in the second step (c) said roll bite for determining temperature rise [Delta] T _f in the roll bite in the rolling state by subtracting the stand entry side temperature temperature [Delta] T _f There when exceeding a heat scratch control target temperature [Delta] T _L which is set in advance, the rolling load of the first step, work roll speed , Stand delivery side speed, thickness at delivery side of the stand incident and, and a third step (d) the detected value of the first step of obtaining a friction coefficient and deformation resistance of the rolled material from the detected value of the stand entry-exit side tension, and, the The plate temperature rise T _E ′ in the roll bite in the rolled state is obtained from the friction coefficient and deformation resistance obtained in 3 steps, and the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount is changed is obtained, Roll bite inner plate temperature rise T _m when the lubricating oil concentration and / or the lubricating oil supply amount is changed using the detected value of the first step, the friction coefficient μ ′ and the deformation resistance obtained in the third step. _{'seek, ΔT L -ΔT f ≧ T m} ' -T E ' to become the lubricant concentration and / or the fourth step (e) for obtaining the lubricating oil supply amount lubricant concentration and was determined in the fourth step Alternatively, when the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step is changed, the lubricating oil concentration and / or the lubricating oil supply amount is controlled with the lubricating oil supply amount as a target value. Sixth step of controlling the plate thickness and shape corresponding to the friction coefficient μ ′ Cold tandem rolling, in which a stand that is prone to heat scratching is designated in advance, and rolling is performed in the designated stand by the following steps while performing plate cooling (water cooling) between the rolling mill roll bite and the plate temperature detector. Rolling method in the machine.
(B) Stand entry side plate temperature, stand exit side plate temperature, rolling load, work roll speed, stand exit side plate speed, stand entry / exit plate thickness, stand entry / exit side tension, lubricant concentration, lubricant supply amount, plate cooling First step of detecting the water temperature and the plate cooling water supply amount (b) From the detected values of the stand outlet side plate temperature, stand outlet side plate speed, stand outlet side plate thickness, plate cooling water temperature, and plate cooling water supply amount estimates the plate temperature multiple times, based on the estimated the plate temperature data, determine the roll bite outlet plate temperature T _f in the rolling condition, the roll bite in the rolling state from the T _f by subtracting the stand entry side temperature The second step of obtaining the rise temperature ΔT _f at (2) The estimated temperature rise ΔT _{f at the} roll bite is the preset heat scratch control target temperature Δ If _TL is exceeded, the friction coefficient and deformation resistance of the rolled material are calculated from the detected values of rolling load, work roll speed, stand exit side plate speed, stand entry / exit side plate thickness, and stand entry / exit side tension in the first step. Third step (d) to be obtained The plate temperature rise T _E ′ in the roll bite in the rolled state is obtained from the detected value of the first step and the friction coefficient and deformation resistance obtained in the third step, and the lubricating oil concentration and / or The friction coefficient μ ′ when the lubricant supply amount is changed is obtained, and the lubricant concentration and / or lubrication is obtained using the detection value of the first step, the friction coefficient μ ′ and the deformation resistance obtained in the third step. _{'seek, ΔT L -ΔT f ≧ T m} ' roll byte plate temperature increase _{T m} of a case of changing the oil supply amount of lubricating oil concentration and / or lubricating oil supply amount becomes -T _E ' Fourth step (e) Fifth step (f) Fourth step for controlling the lubricating oil concentration and / or the lubricating oil supply amount with the lubricating oil concentration and / or the lubricating oil supply amount obtained in the fourth step as target values Sixth step of controlling the plate thickness and shape in accordance with the friction coefficient μ ′ when the lubricating oil concentration and / or the lubricating oil supply amount obtained in step 1 is changed

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