JPWO2010029624A1 - Rolling speed control method for cold tandem rolling mill - Google Patents

Abstract

Provided is a rolling speed control method for a cold tandem rolling mill that can reliably prevent the temperature of a rolled material taken up by a winder after rolling from exceeding an upper limit. For this reason, based on the temperature model generated for each stand, the predicted temperature of the rolled material when rolled at the temporary rolling speed, with the rolling speed of each stand and the rolling material temperature on the entry side of each stand as variables, From the temperature model of the stand on the most upstream side, a step of calculating the temporary predicted temperature of the rolled material when it is wound up by the winder, and the temporary predicted temperature and a preset comparison value If the predicted temperature and the preliminary predicted temperature are higher than the comparison value, the corrected rolling speed is obtained by decelerating and correcting the temporary rolling speed so that the predicted temperature of the rolled material calculated based on the temperature model is lower than the comparative value. And a step of rolling a rolled material by operating a cold tandem rolling mill at a corrected rolling speed.

Description

  The present invention relates to a rolling speed control method for a cold tandem rolling mill that rolls a rolled material such as metal.

  The control device of the rolling mill is usually composed of a high-order computer such as a vidicon. This control apparatus receives rolling material information and product information, performs setting calculation so that a desired product can be obtained from the rolling material, and performs initial settings such as a pass schedule. And after a rolling material approachs a rolling mill, the plate | board thickness of a rolling material is measured with the sensor installed on the line, and dynamic control is implemented. Generally, in the case of a cold tandem rolling mill, the feasible rolling speed is calculated in consideration of the performance of each stand such as the motor capacity. Then, after the rolling of the rolled material is started, if there is no particular factor that hinders rolling, the rolling is performed up to the rolling speed calculated by the setting calculation.

  Here, when winding a rolled material, such as stainless steel, in which surface quality is important, a slip sheet may be inserted so that the surface is not damaged by winding the coil. This slip-sheet generates burn-in when the temperature exceeds a certain temperature. Due to this burn-in, the interleaf paper adheres to the coil or becomes brittle. If this phenomenon occurs, it causes trouble when rewinding in the next process. In the worst case, the slip sheet may ignite. Thus, when inserting a slip sheet between rolled materials, it is not sufficient to determine the rolling speed considering only the performance of the rolling mill, and it is necessary to prevent the temperature of the rolled material from exceeding the upper limit. is there.

  As a conventional technique for determining the rolling speed of the rolling mill in consideration of the temperature of the rolled material, the rolling material temperature on the roll bite exit side in the rolling mill specified in advance based on the measurement value by the thermometer is estimated, If the estimated temperature of the rolled material is higher than the temperature at which heat scratching occurs, one that corrects the speed has been proposed (for example, see Patent Document 1).

  As another conventional technique, a method has been proposed in which the temperature of the rolled material is measured with a thermometer, and the rolling speed is corrected when the measured value is higher than the seizure temperature of the slip sheet (see, for example, Patent Document 2). ).

Japanese Unexamined Patent Publication No. 2000-167614 Japanese Unexamined Patent Publication No. 6-190421

  However, the one described in Patent Document 1 focuses on prevention of heat scratches. For this reason, no consideration is given to the temperature of the rolled material after the rolling mill. On the other hand, although the thing of patent document 2 considers the sticking temperature of an interleaf as a rolling material temperature after a rolling mill, dynamic control is implemented based on the measured value by a thermometer. However, in dynamic control, unless the rolling speed is actually increased, the temperature of the rolled material will not be known. For this reason, for example, there is a case where a delay occurs in the control due to a transfer time delay or the like such as when acceleration is performed at once, and the temperature of the rolled material exceeds the upper limit.

  The present invention has been made to solve the above-described problems, and its purpose is a cooling that can surely prevent the temperature of the rolled material taken up by the winder after rolling from exceeding the upper limit. It is to provide a rolling speed control method for an intermediate tandem rolling mill.

  A rolling speed control method for a cold rolling mill according to the present invention includes a step of determining a temporary rolling speed of a cold tandem rolling mill in which a plurality of stands are arranged in tandem, and rolling when the rolling is performed at the temporary rolling speed. Based on the temperature model generated for each stand using the rolling speed of each stand and the temperature of the rolled material on the entry side of each stand as variables, the predicted temperature of the material is sequentially determined from the temperature model of the most upstream stand. The step of calculating and calculating the temporary predicted temperature of the rolled material when wound by the winder, the step of comparing the temporary predicted temperature with a preset comparison value, and the temporary predicted temperature If higher than the comparison value, calculate a corrected rolling speed that has been corrected to reduce the temporary rolling speed so that the predicted temperature of the rolled material calculated based on the temperature model is lower than the comparison value, Modified rolling speed It is obtained and a step of rolling the rolling material by operating the tandem cold rolling mill.

  According to this invention, it can prevent reliably that the temperature of the rolling material wound by the winder after rolling exceeds an upper limit.

It is a whole block diagram explaining the cold tandem rolling mill in which the rolling speed control method of the cold tandem rolling mill in Embodiment 1 of this invention is utilized. It is a flowchart for demonstrating the rolling speed control method of the cold tandem rolling mill in Embodiment 1 of this invention. It is a flowchart for demonstrating the learning method of the temperature model utilized with the rolling speed control method of the cold tandem rolling mill in Embodiment 1 of this invention.

Explanation of symbols

1 cold tandem rolling mill, 2 first stand, 3 second stand,
4 third stand, 5 fourth stand, 6 rolling direction, 7 rolled material,
8 Winding machine, 9 Thermometer, 10 Control device

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
FIG. 1 is an overall configuration diagram illustrating a cold tandem rolling mill in which a rolling speed control method for a cold tandem rolling mill according to Embodiment 1 of the present invention is used.
In FIG. 1, 1 is a batch type cold tandem rolling mill. As for this cold tandem rolling mill 1, the 1st stand-the 4th stands 2-5 are arranged in tandem. The cold tandem rolling mill 1 has a function of rolling the rolled material 7 in the rolling direction 6 indicated by an arrow. A rewinding machine (not shown) is provided on the entry side of the cold tandem rolling mill 1. The rewinding machine has a function of rewinding the coiled rolled material 7 and feeding it to the cold tandem rolling mill 1. Furthermore, when the cold tandem rolling mill 1 is a continuous type, a welding machine and a looper (both not shown) are installed between the unwinding machine and the cold tandem rolling mill 1. Thereby, the continuous rolled material 7 enters the cold tandem rolling mill 1 and is rolled.

  On the other hand, a winder 8 is provided on the exit side of the cold tandem rolling mill 1. The winder 8 has a function of winding the rolled material 7 rolled by the cold tandem rolling mill 1 into a coil shape. Here, when the rolled material 7 is stainless steel, a slip sheet (not shown) is inserted between the rolled materials 7 wound up by the winder 8. Thereby, the quality of the surface of the rolling material 7 is maintained. A thermometer 9 is disposed in the vicinity of the rolled material 7 between the cold tandem rolling mill 1 and the winder 8. Usually, since it is not installed in the cold tandem rolling line, the thermometer 9 is a portable type. The thermometer 9 has a function of measuring the actual temperature of the rolled material 7 rolled by the cold tandem rolling mill 1. Here, when the rolled material 7 is made of stainless steel having a glossy surface, in order to accurately measure the temperature of the rolled material 7, sufficient attention should be paid to appropriate adjustment of the emissivity of the rolled material 7, measurement environment, and the like. There is a need.

  The stands 2 to 5, the rewinding machine, the winder 8, and the thermometer 9 are connected to the control device 10. This control device 10 has a function of controlling the entire cold tandem rolling mill 1 such as the rolling speed of each of the stands 2 to 5 and the winding speed of the winder 8. Specifically, the control device 10 has a function of determining the rolling speed of each of the stands 2 to 5 based on the speed cone and the motor capacity of each of the stands 2 to 5. The speed cone is the maximum rolling speed of each of the stands 2 to 5 determined from the motor rating (top speed), gear ratio, and roll diameter.

  Here, the rolled material 7 is rolled and extended from the upstream side to the downstream side of the cold tandem rolling mill 1. That is, it is necessary to make the plate thickness of the rolled material 7 on the downstream side thinner than the plate thickness of the rolled material 7 on the upstream side. Therefore, in order to satisfy the mass flow constant law, it is necessary to slow down the speed cone of the upstream stand 1 and the like and to speed up the speed cone of the downstream stand 4 and the like. Moreover, each stand 2-5 cannot rotate beyond a speed cone. Therefore, it is necessary to set the rolling speed of each stand 2 to 5 below the speed cone.

  Furthermore, when rolling the rolling material 7, a torque generate | occur | produces in the rolling roll of each stand 2-5. When this torque exceeds the motor capacity of each of the stands 2 to 5, rolling cannot be performed. Therefore, when determining the rolling speed of each stand 2-5, it is necessary to estimate and calculate the torque applied to the rolling rolls of each stand 2-5, and to confirm that it is less than the motor capacity of each stand 2-5. And when this torque exceeds the motor capacity of each stand 2-5, the rolling speed of each stand 2-5 is lowered | hung so that the torque concerning the rolling roll of each stand 2-5 may become below motor capacity. Must be set.

  Furthermore, the control apparatus 10 is provided with the function which calculates the estimated temperature of the rolling material 7 based on the temperature model produced | generated for every stand 2-5. This temperature model is usually included in a setting calculation function for determining a pass schedule and the like. This temperature model uses variables related to the rolling speed of each of the stands 2 to 5 such as processing heat generation, friction heat generation, cooling by contact with the rolling roll, etc., and considering cooling by coolant, air cooling, etc. The temperature of the rolled material 7 is predicted. Detailed mathematical formulas of the temperature model are clarified in, for example, “Theory and Practice of Plate Thickness Rolling” (Japan Iron and Steel Institute). For this reason, in this Embodiment, description of detailed numerical formula etc. is abbreviate | omitted.

  Based on the above-described temperature model, the control device 10 uses the rolling speed of each of the stands 2 to 5 obtained by the setting calculation function and the thickness of the rolled material 7 as variables, and the temperature of the first stand 2 arranged at the most upstream position. The model has a function of calculating the predicted temperature of the rolled material 7 in order from the model. And finally, the control apparatus 10 predicts the estimated temperature of the rolled material 7 on the outlet side of the fourth stand 5 arranged on the most downstream side, and further the rolling material 7 at the position where the rolled material 7 is wound up by the winder 8. A function to calculate the predicted temperature is provided. Note that the temperature model is complicatedly associated with other models. For this reason, in the setting calculation, the temperature model may be regenerated by repeated calculation.

  Further, the control device 10 has a function of comparing the provisional predicted temperature of the rolled material 7 with a preset comparison value. Further, the control device 10 has a function of operating the cold tandem rolling mill 1 at the temporary rolling speed when the temporary predicted temperature is lower than the comparison value. In addition, when the temporary predicted temperature is higher than the comparison value, the control device 10 corrects the temporary rolling speed at a reduced speed so that the predicted temperature of the rolled material 7 calculated based on the temperature model is lower than the comparative value. A function of calculating the corrected rolling speed and operating the cold tandem rolling mill 1 at the corrected rolling speed is provided. In the present embodiment, the comparison value is set to the burn-in temperature of the slip sheet.

Next, the rolling speed control method of the cold tandem rolling mill 1 will be described in more detail with reference to FIG.
FIG. 2 is a flowchart for explaining a rolling speed control method for the cold tandem rolling mill according to Embodiment 1 of the present invention.
First, in step S1, the provisional rolling speed of the cold tandem rolling mill 1 is determined in consideration of the speed cone and motor capacity of each of the stands 2 to 5, and the process proceeds to step S2. In step S <b> 2, the predicted temperature of the rolled material 7 is calculated sequentially from the most upstream first stand 2, and the temporary predicted temperature of the rolled material 7 at the position of the winder 8 is calculated. Next, the process proceeds to step S3, and the comparison is made between the temporary predicted temperature and the slip-in temperature of the slip sheet. If the provisional predicted temperature is lower than the burn-in temperature of the slip sheet, the operation ends. With such control, the cold tandem rolling mill 1 operates at a temporary rolling speed.

  On the other hand, if the temporary predicted temperature is higher than the burn-in temperature of the slip sheet in step S3, the process proceeds to step S4. In step S4, the temporary rolling speed of the cold tandem rolling mill 1 is corrected to be reduced. And it returns to step S2 and calculates the predicted temperature of the rolling material 7 from the cold tandem rolling mill 1 entrance side to the position of the winder 8 one by one based on the temperature model. This calculation is repeated, and the corrected rolling speed of the cold tandem rolling mill 1 is calculated and the operation ends when the predicted temperature of the rolled material 7 is equal to or lower than the seizure temperature of the slip sheet. With this control, the cold tandem rolling mill 1 operates at a corrected rolling speed that is a maximum rolling speed that is equal to or lower than the seizure temperature of the slip sheet.

Next, a temperature model learning method will be described with reference to FIG.
FIG. 3 is a flowchart for explaining a temperature model learning method used in the rolling speed control method of the cold tandem rolling mill according to Embodiment 1 of the present invention.
The temperature model must be sufficiently adjusted when the cold tandem rolling mill 1 is started up. Therefore, when the cold tandem rolling mill 1 is started up, a thermometer 9 is prepared, the temperature of the rolled material is manually measured for each steel type and sheet thickness, and the temperature model is adjusted. Hereinafter, a specific procedure for adjusting the temperature model will be described.

  First, tracking points are created on the rolled material 7 at a certain timing. This tracking point is tracked from the entry side of the cold tandem rolling mill 1 to the position of the thermometer 9. And every time a tracking point reaches | attains the plate thickness meter (not shown) provided corresponding to each stand 2-5 by step S11, the related performance rolling data are collected. Finally, the actual temperature for learning of the rolled material 7 is collected by the thermometer 9, and the process proceeds to step S12.

  In step S12, the collected actual rolling data is used as a variable, and the predicted temperature of the rolled material 7 is calculated using the actual rolling data as a variable in order from the temperature model of the first stand 2 on the most upstream side, and finally, The learning predicted temperature of the rolled material 7 at the position of the thermometer 9 is calculated. In step S13, the actual learning temperature is compared with the predicted learning temperature. Here, if there is no error in the temperature model, the actual learning temperature matches the predicted learning temperature. However, in general, the temperature model includes an error. For this reason, the temperature model is learned to eliminate the error.

  That is, when the actual learning temperature is lower than the predicted learning temperature, the process proceeds to step S14. In step S14, the learning gain is set to a smaller value in accordance with the error between the actual learning temperature and the predicted learning temperature, and the process proceeds to step S15. In step S15, the learning value of the temperature model is calculated based on the set gain, and the operation ends. On the other hand, if the actual learning temperature is higher than the predicted learning temperature in step S13, the process proceeds to step S16. In step S16, the learning gain is set to a larger value in accordance with the error between the actual learning temperature and the predicted learning temperature, and the process proceeds to step S15. In step S15, the learning value of the temperature model is calculated based on the set gain, and the operation ends.

  According to Embodiment 1 demonstrated above, when temporary prediction temperature is higher than a comparison value, temporary rolling is performed so that the prediction temperature of the rolling material 7 calculated based on a temperature model may become lower than a comparison value. A corrected rolling speed obtained by decelerating and correcting the speed is calculated. The cold tandem rolling mill 1 operates at a corrected rolling speed to roll the rolled material 7. For this reason, it can prevent reliably that the temperature of the rolling material 7 after rolling exceeds an upper limit.

  The temporary predicted temperature is determined to be the upper limit rolling speed allowed by the cold tandem rolling mill 1. And when temporary prediction temperature is lower than a comparison value, the cold tandem rolling mill 1 is operated at the temporary rolling speed, and the rolling material 7 is rolled. For this reason, while preventing reliably the temperature of the rolling material 7 after rolling exceeding an upper limit, the rolling material 7 can be rolled by the maximum rolling speed which can be implemented. Furthermore, since the comparison value is set to the burn-in temperature of the slip sheet, the burn-in of the slip sheet can be surely prevented, and the work rate does not decrease even in the downstream process.

  In addition, the control device 10 learns the temperature model so as to reduce an error between the actual temperature of the rolled material 7 and the predicted temperature for learning. For this reason, it can prevent more reliably that the temperature of the rolling material 7 after rolling exceeds an upper limit. Specifically, when the actual learning temperature is lower than the predicted learning temperature, the control device 10 decreases the learning gain of the temperature model according to the difference between the actual learning temperature and the predicted learning temperature, When the actual learning temperature is higher than the predicted learning temperature, the learning gain of the temperature model is increased according to the difference between the actual learning temperature and the predicted learning temperature. For this reason, when the temperature model removes the predicted temperature higher, the stability of the learned value is emphasized, and when the temperature model removes the predicted temperature lower, the followability of the learned value can be improved. .

  More specifically, the actual rolling data of the tracking point of the rolled material 7 is measured by a plate thickness meter provided corresponding to each of the stands 2 to 5. And learning temperature prediction temperature is computed by making these performance rolling data into a variable. For this reason, a more accurate temperature model can be learned. When the thermometer 9 is always installed, the temperature model can be learned online to improve the accuracy of the temperature model.

  Note that in the first embodiment, the case where the burn-in temperature of the slip sheet is used as a comparison value has been described. However, the comparison value may not be limited to the burn-in temperature of the slip sheet. For example, when the cold tandem rolling mill 1 is combined with an annealing line or a pickling line in order to improve production efficiency, a temperature suitable for these lines may be used as a comparison value. In this case, it is possible to prevent stagnation in the annealing line and the pickling line that may occur when the rolling speed of the cold tandem rolling mill 1 is changed by dynamic control. That is, stable operation of the entire line can be performed.

  Further, the rolling speed control method of the cold tandem rolling mill 1 described in the first embodiment can cope with a change in the pass schedule of the cold rolling mill that cannot be handled by the operation know-how obtained through experience. Furthermore, it goes without saying that the rolling speed control method of the cold tandem rolling mill 1 described in Embodiment 1 can be applied to other cold rolling mills such as a single reverse cold mill.

  As described above, according to the rolling speed control method of the cold tandem rolling mill according to the present invention, it is possible to reliably prevent the temperature of the rolled material wound around the winding machine after rolling from exceeding the upper limit.

More specifically, each time it reaches each of the stands 2 to 5 and the thickness gauge, actual rolling data related to the tracking points of the rolled material 7 is collected . And learning temperature prediction temperature is computed by making these performance rolling data into a variable. For this reason, a more accurate temperature model can be learned. When the thermometer 9 is always installed, the temperature model can be learned online to improve the accuracy of the temperature model.

Claims (6)

Determining a provisional rolling speed of a cold tandem rolling mill in which a plurality of stands are arranged in tandem;
Based on the temperature model generated for each stand, the predicted temperature of the rolled material when rolled at the temporary rolling speed is a variable based on the rolling speed of each stand and the rolling material temperature on the entry side of each stand. From the temperature model of the stand on the upstream side, in sequence, calculating a temporary predicted temperature of the rolled material when being wound by a winder,
Comparing the temporary predicted temperature with a preset comparison value;
When the temporary predicted temperature is higher than the comparison value, a corrected rolling speed obtained by reducing and correcting the temporary rolling speed so that the predicted temperature of the rolled material calculated based on the temperature model is lower than the comparative value. And rolling the rolled material by operating the cold tandem rolling mill at the corrected rolling speed,
A rolling speed control method for a cold tandem rolling mill. The temporary rolling speed is determined to be the upper rolling speed allowed by the cold tandem rolling mill,
2. The cold tandem rolling mill according to claim 1, wherein when the temporary predicted temperature is lower than the comparison value, the cold tandem rolling mill is operated at the temporary rolling speed to roll the rolled material. Rolling speed control method.   3. The comparison value according to claim 1 or 2, wherein the comparison value is set to a seizure temperature of a slip sheet inserted between the rolled materials when the winder winds the rolled material. Rolling speed control method for cold tandem rolling mill. Operating the cold tandem rolling mill at a learning rolling speed, and measuring a learning actual temperature of the rolled material with a thermometer provided between the cold tandem rolling mill and the winder;
Based on the temperature model, calculating a learning predicted temperature of the rolled material when rolled at the learning rolling speed and wound by the winder;
Comparing the actual learning temperature and the predicted predicted temperature;
Learning the temperature model so as to reduce an error between the learning actual temperature and the learning predicted temperature;
The rolling speed control method of the cold tandem rolling mill according to any one of claims 1 to 3, wherein the rolling speed control method is provided. When the learning actual temperature is lower than the learning predicted temperature, the learning gain of the temperature model is reduced according to the error between the learning actual temperature and the learning predicted temperature,
The learning gain of the temperature model is increased in accordance with an error between the actual learning temperature and the predicted learning temperature when the actual learning temperature is higher than the predicted learning temperature. Item 5. A rolling speed control method for a cold tandem rolling mill according to Item 4. On the entry side of the cold tandem rolling mill, create a tracking point on the rolled material,
In the thickness gauge provided for each stand, collect the actual rolling data of the tracking point,
The actual temperature for learning the tracking point is measured with the thermometer,
6. The cold tandem rolling mill according to claim 4, wherein the learning predicted temperature is calculated using the actual rolling data as a variable in order from the temperature model of the most upstream side stand. Rolling speed control method.

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