JP3552681B2 - Advanced rate control method in cold rolling - Google Patents

Description

不感帯判定部８Ｂでは、入力した先進率ｆが、設定されている安全先進率の範囲外であるかどうかが判定され、先進率ｆが上記範囲の下限値Ｌより小さい若しくは上限値Ｈより大きいと判定すれば、図２に示すグラフに基づき、上記上限値Ｈ若しくは下限値Ｌからの相対値に応じた濃度変化量を算出して、出力部に出力する。
【００１８】
ここで、上記安全先進率の範囲の上限値Ｈ及び下限値Ｌは、予め次のようにして求めておく。すなわち、安定先進率の範囲として、当該範囲を越えるとチャタリング発生する懸念がある領域を予め実験などから求めておき、この範囲内で安全先進率の範囲を設定する。
本実施形態では、上記安全先進率の範囲として１％以上４％以下としてある。ただし、許容幅として０．５％を見込んで、上記各境界値よりもそれぞれ０．５％小さな値を限界値として安全先進率の範囲を設定している。すなわち、１．５％を下限値Ｌ、３．５％を上限値Ｈとしている。
【００１９】
なお、上記のように許容幅を見込んで安全先進率の範囲を設定することが、チャタリングをより確実に防止するという点で有利であるが、許容幅を見込まず、安全先進率を安定先進率と同じ範囲として設定しても良い。
出力部８Ｃでは、入力した濃度変化量を圧延油供給装置９の濃度コントローラ２４に出力する。圧延油供給装置９では、入力した濃度変化量だけ目標濃度を変化させた濃度となるように制御を行いながら、各ヘッダ１４のノズルから圧延潤滑油をストリップ２の表面に噴射する。
【００２０】
次に、本実施形態の圧延油供給装置９の構成を説明する。図３は、本実施形態に係る圧延油供給装置９を示す構成概要図である。
すなわち、符号１２は高濃度の圧延油を供給する高濃度用タンクであり、高濃度用供給路２２を通じて、ヘッダ１４直下に配置されたミキサ２０に接続されている。その高濃度用供給路２２には、上流側からブースタポンプ２５及び精密ギアポンプ２１が介装されて、ミキサ２０に吐出する圧延油の供給流量を高応答で制御可能となっている。なお、符号１７は戻り路を示している。
【００２１】
また、符号１１は、水あるいは低濃度の圧延油を供給する低濃度用タンクであり、低濃度用供給路２３を通じて上記ミキサ２０に接続され、当該低濃度用供給路２３に介装された低濃度用ポンプ１５によって水あるいは低濃度の圧延油をミキサ２０に供給可能となっている。なお、低濃度の圧延油の濃度としては、例えば対象とするストリップに供給する圧延油として想定され得る最低の濃度とすればよい。
【００２２】
上記ミキサ２０は、ヘッダ１４の直前に配置されて、タンク１２から供給されてきた高濃度の圧延油と、タンク１１から供給される水あるいは低濃度の圧延油とを連続的に混合してヘッダ１４に排出する。ヘッダ１４は供給されてきた所定濃度の圧延油を、最終スタンド１Ｆ入側のストリップ２表面に向けて噴射可能となっている。
【００２３】
上記構成の圧延油供給装置９における圧延油の濃度制御について説明すると、低濃度用タンク１１から圧送される水あるいは低濃度の圧延油を一定の流量に制御しておく。そして、要求される目標濃度となるように、濃度コントローラ２４によって精密ギアポンプ２１の吐出流量が制御される。但し、濃度コントローラ２４は、先進率制御装置８から濃度変化量を入力した場合には、該濃度変化量だけ上記目標濃度を変化させた濃度値となるように精密ギアポンプ２１の吐出流量を制御する。すなわち、濃度コントローラ２４は、低濃度用タンク１１からの供給流量、圧延油濃度、及び目標濃度（濃度変化量を入力した場合には該濃度変化量を加味した濃度値）に基づいて、ヘッダ１４から供給される圧延油が目標濃度となる高濃度の圧延油の供給流量を求め、当該供給流量となるように精密ギアポンプ２１に吐出量の指令を送る。なお、低濃度用タンク１１からのミキサ２０への供給流量は、例えばヘッダ１４のノズルからの噴出流量が目標流量（濃度変化量を入力した場合には該濃度変化による流量変化を加味した流量）となるように設定すればよい。
【００２４】
次に、上記設備における作用・効果などについて説明する。
ストリップ２は、各スタンド１Ａ〜１Ｆで順番に圧延され、続いて最終スタンド１Ｆからブライドルロールを介してコイラに送られて巻き取られる。
そして、演算した最終スタンド１Ｆでの先進率が、設定されている安全先進率の範囲内であれば、チャタリングが発生しないと推定されるので、先進率制御のために圧延潤滑油濃度の調整を行わない。一方、演算した最終スタンド１Ｆでの先進率が安全先進率の範囲外であれば、上記図２に基づき、濃度変化量を求めて圧延油供給装置９に供給され、該圧延油供給装置９は、目標濃度から入力した濃度変化量分の濃度変化を生じさせるべく、高濃度用タンク１２からの圧延油のミキシングタンクへの供給流量を変化する。
【００２５】
このように圧延油潤滑油の濃度を調整することで、先進率が安全先進率の範囲内に入るように制御されて、一番チャタリングが発生しやすい最終スタンド１Ｆでのチャタリングの発生が防止される。
ここで、上記構成の圧延油供給装置９では、低濃度用タンク１１から供給される水又は低濃度の圧延油に対し、ヘッダ１４直前にて必要な分だけの高濃度の圧延油を追加混合してヘッダ１４に供給することで、目標とする濃度に調整された圧延油がストリップ２に供給される。このようにヘッダ４直前で濃度の調整を行うために、圧延油の濃度調整の応答性が高い。つまり、高応答で先進率の制御を行うことができる。
【００２６】
なお、ヘッダ１４直前に配置されたミキサ２０において、水と圧延油を混合して濃度調整をする場合、ミキシング不足からＥＭＩ（Ｅｍｕｌｓｉｏｎ Ｓｔａｂｉｌｉｔｙ Ｉｎｄｅｘ：乳化安定度）が低くなりやすく、ヘッダから供給されるエマルジョンの粒径が大きくなりやすい。特に、このような点が問題とされる場合は、低濃度用タンク１１から低濃度の圧延油を供給すると、圧延油同士を混合することとなり乳化安定性が良く、また、粒径の拡大を伴うこともないので好ましい。
【００２７】
なお、ここで、上記実施形態においては、安全先進率の上限値Ｈ若しくは下限値Ｌからの演算した先進率の変位量に一次比例した量だけ濃度変化させているが、これに限定されない。例えば階段状に上記変位量と濃度変化量とを対応付けておいてもよい。
なお、低濃度の圧延油の濃度は高いＥＳＩを確保する場合は１％以上とすることが好ましい。また、全てのストリップ２への対応を可能とするため、高濃度の圧延油の濃度の下限値は、想定している圧延油の最高の濃度を超える濃度とすることが好ましい。高濃度の圧延油の濃度の上限値は１００％（圧延油の原油の濃度）である。高濃度の圧延油の少量の変化で高応答にミキサ２０での圧延油の濃度を調整可能とするという観点からは、高濃度の圧延油は圧延油の原液とするのが好ましい。
【００２８】
また、上記実施形態ではミキサをヘッダ直前に配置したが、このミキサをヘッダ内に配置してもよい。
【００２９】
【発明の効果】
以上説明したきたように、本発明の先進率制御によれば、効率良くチャタリングを防止することが可能となる。
【図面の簡単な説明】
【図１】本発明に基づく実施形態に係る冷間圧延設備を示す概略構成図である。
【図２】本発明に基づく実施形態に係る先進率と濃度変化量との関係を示す図である。
【図３】本発明に基づく実施形態に係る圧延油供給装置を示す概略構成図である。
【符号の説明】
１ 連続圧延機
１Ｆ 最終スタンド
２ ストリップ
３ ブライドルローラ
４ コイラー
５ 最終スタンドのワークロール
６，７ 回転数センサ
８ 先進率制御装置
８Ａ 先進率演算部
８Ｂ 不感帯判定部
８Ｃ 出力部
９ 圧延油供給装置
１１ 低濃度用タンク
１２ 高濃度用タンク
１４ ヘッダ
１５ 低濃度用ポンプ
２０ ミキサ
２１ 精密ギアポンプ（高濃度用ポンプ）
２２ 高濃度用供給路
２３ 低濃度用供給路
２４ 濃度コントローラ
２５ ブースタポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to cold rolling of a metal strip (hereinafter referred to as "strip") such as a steel strip by a cold tandem mill, and particularly to cold rolling found in a thin material such as a hard steel strip. The present invention relates to an advanced rate control method in cold rolling effective for preventing chattering (resonance phenomenon).
[0002]
[Prior art]
As a method of controlling the advance rate, for example, there is a method described in JP-A-61-199507.
In this advanced rate control method, the friction coefficient is obtained from the plate thickness, tension, plate speed, etc., and the influence coefficient of the friction coefficient model formula using the amount of rolling lubricant as a variable is learned and corrected, and the friction coefficient is obtained based on the above friction coefficient model formula. The rolling factors (e.g., tension, inlet side plate thickness, rolling lubricating oil amount) are controlled so that the advanced rate falls within an allowable range. Thus, even if the rolling conditions are changed, the advanced rate can be predicted with sufficient accuracy for practical use, and thereby stable high-speed rolling is to be ensured.
[0003]
In the advanced rate control method described in Japanese Patent Application Laid-Open No. 62-292209, the tension between stands is adjusted so that the advanced rate becomes a preset target advanced rate.
Further, in the advanced rate control method described in Japanese Patent Application Laid-Open No. 62-72409, a friction coefficient to be a target advanced rate is estimated, and a rolling-rolling lubricating oil amount is calculated from a friction coefficient model based on the estimated friction coefficient. The advanced rate is controlled to the target advanced rate by controlling the amount of the lubricating oil for the rolling so as to be the calculated amount.
[0004]
In Japanese Patent Application Laid-Open No. 3-151106, the present advanced ratio is determined, a friction coefficient prediction formula is created from the advanced ratio, and the rolling lubricant concentration that reaches the target advanced ratio is determined from the friction coefficient prediction formula, and the rolling lubricant concentration is determined. The advanced ratio is controlled by controlling the lubricating oil concentration.
[0005]
[Problems to be solved by the invention]
On the other hand, recently, it has become clear that deformation resistance changes during rolling due to a base plate factor, which causes chattering. Therefore, in the method described in Japanese Patent Application Laid-Open No. 61-199507, it is difficult to control the longitudinal direction of the coil, and if the rolling load or the tension is changed so as to follow the deformation resistance change, the thickness of the sheet may fluctuate. is there.
[0006]
In Japanese Patent Application Laid-Open No. 62-292209, the tension between the stands is controlled to be constant. However, since the change in the deformation resistance occurs rapidly, the responsiveness is not improved by controlling the advance rate by such a tension control. There is a problem of shortage.
In the control described in JP-A-62-72409 and JP-A-3-151106, the coefficient of friction at each stand is estimated from the advance rate, and the amount of rolling lubricating oil supply or rolling lubrication is estimated from the estimated coefficient of friction. This is a technology for controlling the concentration of oil. In this technique, control is performed using the estimated friction coefficient.However, the estimated friction coefficient does not always coincide with the actual friction coefficient, and the accuracy is inferior because there is always some deviation, In some cases, it was not possible to follow rapid changes in rolling conditions caused by changes in deformation resistance, and the frequency of chattering could not be sufficiently reduced.
[0007]
Further, when controlling the advanced rate by controlling the supply amount of the rolling lubricating oil, it is difficult to uniformly spray the strip if the supply amount is limited, and the rolling state in the sheet width direction changes, Poor shape of the plate may occur.
In Japanese Patent Application Laid-Open No. 3-151106, the rolling lubricating oil concentration is controlled. However, as described in the upper right column on page 3, the higher the concentration, the larger the amount of oil and the lower the friction coefficient. I have. In addition, control is always performed so that the target density corresponds to the target advanced rate.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide an advanced rate control method in cold rolling that can efficiently prevent chattering from occurring.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is to determine the advance rate at the final stand from the plate speed at the exit side of the final stand and the roll peripheral speed at the final stand in the cold tandem mill. When the calculated advance rate is out of the range of the safety advance rate in which chattering occurrence is determined in advance, the rolling lubrication supplied at the final stand so that the advance rate falls within the range of the safety advance rate. An object of the present invention is to provide an advanced rate control method in cold rolling characterized by adjusting the concentration of oil.
Next, the invention described in claim 2 calculates the advance rate at the final stand from the sheet speed at the exit side of the final stand and the roll peripheral speed at the final stand in the cold tandem mill, and the calculated advance rate is The concentration of the rolling lubricant supplied at the final stand is adjusted immediately before the header or the header so that the advance rate falls within the range of the safety advance rate if the chattering occurrence is determined to be outside the safe advance rate range where chattering occurrence is suppressed in advance. The present invention provides an advanced rate control method in cold rolling, characterized in that adjustment is performed by a mixer arranged in the inside.
[0010]
Here, since it has been confirmed that the advanced ratio decreases as the rolling lubricant concentration is increased, for example, when the upper limit of the stable advanced ratio is exceeded, the rolling oil concentration is offset by the offset from the upper limit. It may be changed so as to be higher, and when it is lower than the lower limit value of the safety advance ratio, the rolling oil concentration may be changed so as to be reduced by the offset from the lower limit value.
[0011]
When the present inventors investigated, most of the chattering occurred in the final stand of rolling, which had the smallest thickness and high deformation resistance.
From this point of view, in the present invention, control efficiency is improved by controlling only the final stand in the cold tandem mill. In addition, if control is performed so that the rolling conditions of the former stand are also changed, this change in the former stage also affects the rolling state of the final stand, which may make rapid control difficult.However, in the present invention, only the final stand is used. This problem can be solved by using That is, the control of the advance rate becomes simpler than in the past.
[0012]
The advanced rate is adjusted by controlling the rolling lubricating oil, but by performing the concentration control, the change in the amount of oil supplied by the control is suppressed to a small degree, and the adverse effect on the rolling is suppressed to a small degree. Can be
Note that, as will be described in an embodiment to be described later, it is possible to set a higher responsiveness when changing the density than when changing the supply amount.
[0013]
Further, since the rolling oil concentration is not always adjusted but is changed only when the rolling oil concentration is out of the predetermined allowable range, the adverse effect on the rolling can be suppressed from this point.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating the rolling mill equipment of the present embodiment. That is, a plurality of stands 1A to 1F of the cold tandem mill 1 are arranged along the strip 2 transport direction, and in FIG. 1, the strips 2 are sequentially transported from the left to the right at the stands 1A to 1F while being transported from left to right. It is to be rolled.
[0015]
A bridle roll 3 and a coiler are arranged downstream of the final stand 1F. The strip 2 coming out of the final stand 1F is wound around the coiler 4 while a predetermined tension is applied by the bridle roll 3.
Then, the rotation speed of the work roll 5 of the final stand 1F is detected by the first rotation speed sensor 6, and the first rotation speed sensor 6 outputs a detection signal to the advanced rate control device 8. Further, the rotation speed of the bridle roll 3 is detected by a second rotation speed sensor 7, and the second rotation speed sensor 7 outputs a detection signal to the advanced rate control device 7.
[0016]
Further, the advanced rate control device 8 includes an advanced rate calculation unit 8A, a dead zone determination unit 8B, and an output unit 8C.
The advanced rate calculation unit 8A calculates the peripheral speed Vr of the work roll 5 of the final stand 1F based on the detection signal from the first rotation speed sensor 6, and calculates the bridle roll 3 based on the detection signal from the second rotation speed sensor 7. Is calculated, the advance rate f is calculated by the following equation (1), and the calculation result is output to the dead zone determination unit 8B.
[0017]

The dead zone determination unit 8B determines whether the input advanced rate f is outside the range of the set safety advanced rate, and if the advanced rate f is smaller than the lower limit L or upper limit H of the above range. If it is determined, based on the graph shown in FIG. 2, the density change amount corresponding to the relative value from the upper limit value H or the lower limit value L is calculated and output to the output unit.
[0018]
Here, the upper limit value H and the lower limit value L of the range of the safety advance rate are obtained in advance as follows. That is, as a range of the stable advanced ratio, a region in which chattering is likely to occur when exceeding the range is determined in advance by an experiment or the like, and a safe advanced ratio range is set within this range.
In the present embodiment, the range of the safety advance rate is set to 1% or more and 4% or less. However, in view of 0.5% as the allowable width, the range of the safety advance ratio is set as a limit value that is 0.5% smaller than each of the above boundary values. That is, the lower limit L is set to 1.5% and the upper limit H is set to 3.5%.
[0019]
Note that setting the range of the safety advance rate in consideration of the allowable range as described above is advantageous in that chattering is more reliably prevented. May be set as the same range as.
The output unit 8C outputs the input amount of concentration change to the concentration controller 24 of the rolling oil supply device 9. The rolling oil supply device 9 injects the rolling lubricating oil from the nozzles of each header 14 onto the surface of the strip 2 while controlling so that the target density is changed by the input density change amount.
[0020]
Next, the configuration of the rolling oil supply device 9 of the present embodiment will be described. FIG. 3 is a schematic configuration diagram illustrating the rolling oil supply device 9 according to the present embodiment.
That is, reference numeral 12 denotes a high-concentration tank for supplying high-concentration rolling oil, which is connected to a mixer 20 disposed immediately below the header 14 through a high-concentration supply path 22. A booster pump 25 and a precision gear pump 21 are interposed in the high-concentration supply path 22 from the upstream side, so that the supply flow rate of the rolling oil discharged to the mixer 20 can be controlled with high response. Reference numeral 17 indicates a return path.
[0021]
Reference numeral 11 denotes a low-concentration tank for supplying water or low-concentration rolling oil. The low-concentration tank is connected to the mixer 20 through a low-concentration supply path 23 and is interposed in the low-concentration supply path 23. Water or low-concentration rolling oil can be supplied to the mixer 20 by the concentration pump 15. Note that the concentration of the low-concentration rolling oil may be, for example, the lowest concentration that can be assumed as the rolling oil supplied to the target strip.
[0022]
The mixer 20 is disposed immediately before the header 14 and continuously mixes the high-concentration rolling oil supplied from the tank 12 with the water or low-concentration rolling oil supplied from the tank 11 to form a header. Discharge to 14 The header 14 is capable of injecting the supplied predetermined concentration of the rolling oil toward the surface of the strip 2 on the entry side of the final stand 1F.
[0023]
The concentration control of the rolling oil in the rolling oil supply device 9 having the above configuration will be described. Water or low-concentration rolling oil fed from the low-concentration tank 11 is controlled at a constant flow rate. Then, the discharge flow rate of the precision gear pump 21 is controlled by the concentration controller 24 so that the required target concentration is obtained. However, when the density change amount is input from the advanced rate control device 8, the density controller 24 controls the discharge flow rate of the precision gear pump 21 so that the density value becomes the density value obtained by changing the target density by the density change amount. . That is, the concentration controller 24 determines the header 14 based on the supply flow rate from the low concentration tank 11, the rolling oil concentration, and the target concentration (when the concentration change amount is input, the concentration value considering the concentration change amount). The supply flow rate of the high-concentration rolling oil at which the rolling oil supplied from the above becomes the target concentration is obtained, and a command for the discharge amount is sent to the precision gear pump 21 so as to achieve the supply flow rate. The supply flow rate from the low-concentration tank 11 to the mixer 20 is, for example, a target flow rate (a flow rate taking into account a flow rate change due to the density change when a density change amount is input). What is necessary is just to set so that it may become.
[0024]
Next, the operation and effect of the above-described equipment will be described.
The strip 2 is rolled in order at each of the stands 1A to 1F, and subsequently sent from the final stand 1F to a coiler via bridle rolls and wound.
If the calculated advance rate at the final stand 1F is within the range of the set safety advance rate, it is estimated that chattering does not occur. Therefore, adjustment of the rolling lubricant concentration for advance rate control is performed. Not performed. On the other hand, if the calculated advance rate at the final stand 1F is out of the range of the safe advance rate, the amount of change in concentration is calculated and supplied to the rolling oil supply device 9 based on FIG. The supply flow rate of the rolling oil from the high-concentration tank 12 to the mixing tank is changed in order to cause a density change corresponding to the input density change amount from the target density.
[0025]
By adjusting the concentration of the rolling oil lubricating oil in this way, the advanced rate is controlled to fall within the range of the safe advanced rate, and the occurrence of chattering in the final stand 1F where chattering is most likely to occur is prevented. You.
Here, in the rolling oil supply device 9 having the above configuration, the necessary amount of high-concentration rolling oil is added to the water or low-concentration rolling oil supplied from the low-concentration tank 11 just before the header 14. By supplying the rolling oil to the header 14, the rolling oil adjusted to the target concentration is supplied to the strip 2. As described above, since the concentration is adjusted immediately before the header 4, the responsiveness of the concentration adjustment of the rolling oil is high. That is, it is possible to control the advance rate with high response.
[0026]
In the case where the concentration is adjusted by mixing water and rolling oil in the mixer 20 disposed immediately before the header 14, the EMI (Emulsion Stability Index: emulsification stability) tends to be low due to insufficient mixing, and is supplied from the header. The particle size of the emulsion tends to be large. In particular, when such a point is considered to be a problem, if a low-concentration rolling oil is supplied from the low-concentration tank 11, the rolling oils are mixed with each other, resulting in good emulsification stability and an increase in particle size. It is preferable because it is not accompanied.
[0027]
Here, in the above embodiment, the density is changed by an amount that is linearly proportional to the displacement of the advanced rate calculated from the upper limit value H or the lower limit value L of the safe advanced rate, but is not limited to this. For example, the displacement amount and the density change amount may be associated in a stepwise manner.
The concentration of the low-concentration rolling oil is preferably 1% or more in order to secure high ESI. In addition, in order to be able to cope with all the strips 2, it is preferable that the lower limit of the concentration of the high-concentration rolling oil be a concentration that exceeds the assumed highest concentration of the rolling oil. The upper limit of the concentration of the high-concentration rolling oil is 100% (the concentration of crude oil in the rolling oil). From the viewpoint that the concentration of the rolling oil in the mixer 20 can be adjusted with high response by a small change of the high-concentration rolling oil, the high-concentration rolling oil is preferably used as a stock solution of the rolling oil.
[0028]
In the above embodiment, the mixer is arranged immediately before the header. However, the mixer may be arranged in the header.
[0029]
【The invention's effect】
As described above, according to the advanced rate control of the present invention, chattering can be efficiently prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a cold rolling facility according to an embodiment based on the present invention.
FIG. 2 is a diagram illustrating a relationship between an advance rate and a density change amount according to an embodiment of the present invention.
FIG. 3 is a schematic configuration diagram showing a rolling oil supply device according to an embodiment based on the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 continuous rolling mill 1F final stand 2 strip 3 bridle roller 4 coiler 5 work roll 6, 7 rotation speed sensor of final stand 8 advanced rate control device 8A advanced rate calculation unit 8B dead zone determination unit 8C output unit 9 rolling oil supply device 11 low Concentration tank 12 High concentration tank 14 Header 15 Low concentration pump 20 Mixer 21 Precision gear pump (high concentration pump)
22 Supply path for high concentration 23 Supply path for low concentration 24 Concentration controller 25 Booster pump

Claims (2)

The advance rate at the final stand is calculated from the plate speed at the exit side of the final stand and the roll peripheral speed at the final stand in the cold tandem mill, and the calculated advance rate is the safety advance rate at which chattering is determined in advance. And controlling the concentration of the rolling lubricating oil supplied at the final stand so that the advanced ratio falls within the range of the safe advanced ratio when the ratio falls outside the range.   The advance rate at the final stand is calculated from the plate speed at the exit side of the final stand and the roll peripheral speed at the final stand in the cold tandem mill, and the calculated advance rate is the safety advance rate at which chattering is determined in advance. Outside the range, the concentration of the rolling lubricating oil supplied at the final stand is adjusted by a mixer disposed immediately before or in the header so that the advanced rate is within the range of the safe advanced rate. The advanced rate control method in cold rolling.

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