JP2007301603A - Method for controlling coiling temperature of rolled stock and rolling equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the production of a rolled stock provided with high quality/high mechanical properties possible by controlling the coiling temperature after performing the heat-transfer calculation of air cooling and the heat-transfer calculation of water cooling and clearly taking both cooling effect into consideration. <P>SOLUTION: In a method for controlling the coiling temperature of the rolled stock 5 by which the coiling temperature of the rolled stock 5 is controlled by performing the water-cooling or the air-cooling of the rolled stock 5 after finish rolling, by performing the heat-transfer calculation of the air cooling to the rolled stock 5 to be air-cooled and performing the heat-transfer calculation of the water cooling to the rolled stock 5 to be water-cooled, the predicted value of the coiling temperature of the rolled stock 5 is calculated and the coiling temperature is controlled on the basis of this predicted value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling material winding temperature control method and a rolling apparatus to which the method can be applied.

Conventionally, a rolled material such as a thin steel plate has been manufactured by introducing a heated slab or base plate into a continuous rolling device and continuously rolling it with a plurality of rolling mills, and downstream of the final rolling mill. Is provided with a winding device for winding the rolled material. Further, a cooling means for cooling while controlling the temperature of the rolled material is provided between the final rolling mill and the winding device.
The cooling means has a cooling bank provided with a plurality of valves for changing the supply amount of the coolant sprayed on the rolled material, and the cooling bank is configured to be connected in the transfer direction of the rolled material. The cooling means adjusts the temperature of the rolled material and controls cooling by changing the number of open valves, which is the number of valves in the open state, so that the final plate temperature (winding temperature) of the rolled material matches the target temperature. Is done.

A number of methods for controlling such a cooling means, that is, methods for controlling the winding temperature of a rolled material have been developed.
For example, the technique described in Patent Document 1 calculates the position of the sampling point and the plate temperature on the rolled material from the actual values of the rolling material transfer speed (plate speed) and the water injection pattern of the cooling bank, From the calculated position of the rolled material and the plate temperature, the plate temperature when the rolled material reaches the winding device (winding temperature) is predicted, and the predicted value and the target value are matched so that the predicted value matches the target value. The water injection pattern is changed.

The technique disclosed in Patent Document 2 determines the delivery target temperature of the cooling bank from the time when the rolling material passes through the cooling bank so that the cooling rate for the rolled material is constant, and the delivery target The number of open valves that satisfy the temperature is determined. The phrase “cooling rate is constant” means that the amount of temperature drop when the rolled material has passed for a certain period of time in the cooling means is constant.
At present, users are requesting the supply of very high-quality rolled material. In order to achieve the required material properties and mechanical properties, the rolling material winding temperature must match the target value. Needless to say, the cooling rate in each cooling bank must be constant.

In order to satisfy this requirement, Patent Document 3 discloses that the amount of water poured in the cooling bank in the water-cooled state is controlled under the condition that the cooling rate for the rolled material is uniform without being affected by the plate speed. A technique for causing the temperature of the rolled material in the apparatus to become a target temperature is disclosed.
JP 58-221606 A JP-A-6-179008 JP-A-5-277535

  However, the technology of Patent Document 3 controls the number of water-cooled cooling banks and the like, and clearly shows the temperature drop in the rolled material in the air-cooled cooling bank or the rolled material before being introduced into the cooling means. It is not something to consider. That is, in the cooling bank in the air cooling state, the temperature drop of the rolled material is considerably smaller than that in the cooling bank in the water cooling state, and is not clearly controlled. Therefore, in producing a rolled material having high quality and high mechanical properties required by the user, the technology of Patent Document 3 considering only the control of the cooling bank in the water-cooled state provides sufficient cooling control of the rolled material. It is difficult to do.

  Therefore, in view of the above problems, the present invention performs air-cooling heat transfer calculation and water-cooling heat transfer calculation for the rolled material and clearly considers both cooling effects, and then controls the coiling temperature. An object of the present invention is to provide a rolling material winding temperature control method and a rolling device that can produce a rolled material having high quality and high mechanical properties.

In order to achieve the above object, the present invention takes the following technical means.
That is, the rolling material winding temperature control method according to the present invention controls the rolling temperature of the rolled material by cooling the rolled material after finish rolling by water cooling or air cooling, and is air-cooled. The air-cooled heat transfer calculation is performed on the rolled material, the water-cooled heat transfer calculation is performed on the water-cooled rolled material, and the predicted value of the winding temperature of the rolled material is calculated. The coiling temperature is controlled based on the value.
This makes it possible to perform air-cooling heat transfer calculation and water-cooling heat transfer calculation for the rolled material, and to control the coiling temperature with clear consideration of both cooling effects, providing high quality and high mechanical properties. Rolled material can be produced.

Further, the cooling of the rolled material is performed using a cooling means including a plurality of cooling banks that can be operated in a cooling capacity and can be in an air-cooled state. In the cooling bank in the air-cooled state, the rolling material is cooled. Air-cooled heat transfer calculation is performed, and in the water-cooled cooling bank, the water-cooling heat transfer calculation for the rolled material is performed under the condition that the cooling rate is constant, and the predicted value of the winding temperature of the rolled material is calculated. It is preferable to set each cooling bank to either an air-cooled state or a water-cooled state based on the value to control the winding temperature.
As a specific method for setting each cooling bank to either an air-cooled state or a water-cooled state, a plurality of coil pieces obtained by performing sampling at a certain length or every predetermined time for the rolled material are set,
(i) For each coil piece, the temperature up to the inlet side of the cooling bank in the uppermost stream of the cooling means by performing air-cooling heat transfer calculation using the plate temperature, plate thickness and plate speed after finish rolling. Calculate the descent
(ii) Assuming that only the cooling bank located at the uppermost stream is in a water-cooled state, after calculating the predicted value of the coil piece winding temperature,
(iii) Calculate the predicted value of the coiling temperature by increasing the cooling bank in the water-cooled state from the upstream side to the downstream side of the cooling means,
(iv) The number of cooling banks in the water-cooled state when the predicted value matches or approaches the target value may be applied to the cooling means.

In addition, a plurality of coil pieces obtained by performing sampling at a certain length or certain time for the rolled material,
(i) For each coil piece, the temperature up to the cooling bank inlet side located on the most downstream side of the cooling means by performing air-cooling heat transfer calculation using the plate temperature, plate thickness and plate speed after finish rolling. Calculate the descent
(ii) Assuming that only the cooling bank located at the most downstream side is in a water-cooled state, after calculating a predicted value of the coiling coil winding temperature,
(iii) Increase the cooling bank in the water-cooled state from the downstream side to the upstream side of the cooling means to calculate the predicted value of the winding temperature,
(iv) The number of cooling banks in the water-cooled state when the predicted value matches or approaches the target value may be applied to the cooling means.

More preferably, the actual value of the plate temperature is measured using one or a plurality of intermediate thermometers installed at the intermediate position of the cooling means, and based on the actual values, it is arranged downstream from the intermediate thermometer. The cooling bank may be set to either an air cooling state or a water cooling state, and the winding temperature may be controlled.
Thus, by using the actual value in the intermediate thermometer, the coiling temperature can be controlled with high accuracy, and a rolled material having high quality and high mechanical properties can be produced.
Preferably, in the cooling bank set to the water cooling state, the outlet side plate temperature of the cooling bank is set so that the cooling rate is constant, and the number of open valves is set so as to satisfy the set outlet side plate temperature. The determined number of open valves may be applied to the cooling bank.

Further, in the cooling bank set in the water cooling state, the transport speed of the rolled material is measured, and the amount of decrease in the plate temperature at the cooling bank is calculated using the measured rate, and the amount of decrease in the plate temperature is calculated. It is preferable to calculate the outlet side plate temperature and determine the number of open valves based on the calculated outlet side plate temperature.
Preferably, the sheet temperature after the finish rolling is measured by a sheet thermometer provided on the exit side of the finish rolling mill, and the sheet thickness after the finish rolling is a sheet thickness provided on the exit side of the finish rolling mill. The plate speed after the finish rolling is preferably measured by a speed detector provided in the finish rolling mill.

As the plate temperature, plate thickness, and plate speed after the finish rolling, predicted values set before rolling may be used.
The rolling apparatus that can employ the rolling material winding temperature control method described above includes a rolling machine that rolls the rolled material, a winding apparatus that winds the rolled material rolled by the rolling machine, and the rolling machine and the winding machine. A cooling means that is disposed between the cooling device and has a plurality of cooling banks that can operate in cooling and can be in an air-cooled state, and the air-cooled cooling bank performs air-cooling heat transfer calculation on the rolled material. Performing a water-cooling heat transfer calculation on the rolled material under a condition where the cooling rate is constant in the water-cooled cooling bank, calculating a predicted value of the winding temperature of the rolled material, and based on the predicted value, And a control unit that sets the cooling bank to either an air-cooled state or a water-cooled state and controls the winding temperature.

  According to the rolling material winding temperature control method and apparatus according to the present invention, the air cooling heat transfer calculation and the water cooling heat transfer calculation for the rolled material are performed and the cooling effect of both is clearly considered, and then the winding is performed. Since the temperature can be controlled, a rolled material with high quality and high mechanical properties can be produced.

Hereinafter, a rolling material winding temperature control method and a rolling apparatus according to the present invention will be described by exemplifying a hot continuous rolling apparatus for thin steel sheets.
A rolled material such as a thin steel plate is manufactured by introducing a heated base plate or slab into a continuous rolling apparatus provided with a plurality of rolling mills and continuously rolling the rolled material. The rolling mill provided on the upstream side of the continuous rolling apparatus is a rough rolling mill, and the rolling mill provided on the downstream side is a finish rolling mill that adjusts sheet thickness and the like.
The rolled material that has exited the finish rolling mill provided in the final stage is cooled while passing through the cooling means disposed on the downstream side in the rolling material transfer direction, and is taken up by a winding device.

[First Embodiment]
FIG. 1 is a conceptual diagram showing a device configuration from the final rolling mill 2 of the continuous rolling device 1 to the cooling means 3 and the winding device 4. In the description of this embodiment, the final rolling mill 2 is simply referred to as a rolling mill. In the transfer direction of the rolled material 5, the side to be transferred (winding device 4 side) is called the downstream side, and the opposite side (rolling machine 2 side) is called the upstream side.
The rolling mill 2 has a pair of work rolls 6 and 6 and a pair of backup rolls 7 and 7 for backing up the work rolls 6 and 6. The rotation axis of the work roll 6 is provided with an exit side plate speed detector 8 that measures the number of rotations and measures the plate speed that is the transfer speed of the rolled material 5.
On the exit side of the rolling mill 2, an exit side plate thermometer 9 that measures the plate temperature that is the temperature of the rolled material 5 is arranged. The exit side plate thermometer 9 is a radiation thermometer that measures the plate temperature based on the amount of heat radiation from the rolled material 5. On the downstream side of the delivery-side plate thermometer 9, an delivery-side thickness meter 10 comprising a γ-ray thickness meter is installed.

Cooling means 3 is provided on the downstream side of the outlet side thickness gauge 10. The cooling means 3 is provided so that a plurality of cooling banks 12 face the upper and lower (front and back) surfaces of the rolled material 5, and the cooling banks 12 are arranged so as to be continuous (1 to N) in the rolling material transfer direction. It becomes the composition which is done.
The cooling bank 12 is provided with a plurality of cooling nozzles for spraying cooling water (cooling material) toward the rolled material 5 to lower the temperature of the rolled material 5, and each cooling nozzle controls on / off of the flow rate of the cooling material. Possible valves are provided. When this valve is opened, the coolant is ejected from the cooling nozzle. Therefore, by changing the number of valves in the open state (number of open valves), the total amount of coolant sprayed from the cooling nozzle to the rolled material 5 is changed. The amount of temperature drop is variable.

A thermometer composed of a radiation thermometer is installed on the downstream side of the cooling bank 12 [N] located on the most downstream side of the cooling means 3 and immediately before the winding device 4, and the cooling bank 12 [N ], The plate temperature of the rolled material 5 that has passed through is measured. Hereinafter, this thermometer is referred to as a winding thermometer 12. The “Nth cooling bank” at the Nth position from the tip of the cooling means 3 is referred to as a cooling bank 12 [N].
A winding speed detector 14 is installed on the rotating shaft of the winding device 4.
The above-mentioned measurement data of the exit side plate thermometer 9, the exit side plate speed detector 8 and the exit side plate thickness meter 10, that is, the actual values of the plate temperature, plate speed, and plate thickness on the exit side of the rolling mill 2 control the cooling means 3. Is input to the control unit 15. Actual values from the winding thermometer 13 and the winding speed detector 14 are also input to the control unit 15.

Based on a rolling material winding temperature control method, which will be described later, the control unit 15 appropriately sets the number of open valves in each cooling bank 12 so that the plate temperature (winding temperature) in the winding thermometer 13 approaches the target temperature. Calculate the value.
The value of the number of opened valves calculated by the control unit 15 is sent to a valve opening / closing signal output unit 16 constituted by a sequencer or the like. The valve opening / closing signal output unit 16 opens and closes the valves of each cooling bank 12 according to the value of the number of opened valves, and changes the cooling state of the entire cooling means 3.
In the case of the present embodiment, the control unit 15 is configured by a process computer, and the valve opening / closing signal output unit 16 is configured by a sequencer, a PLC, or the like.

A first embodiment of a rolling material winding temperature control method executed in the control unit 15 will be described with reference to FIGS.
FIG. 2 shows a hysteresis curve of the plate temperature of the rolled material 5 targeted in the present embodiment. The horizontal axis of this figure pays attention to a coil piece set on the rolled material 5 (a sampling plate obtained by sampling the rolled material at a certain length or every constant time). 2 shows the position (how far it has been transferred) from the exit side of 2 as a base point. The vertical axis represents the plate temperature of the coil piece.

The coil pieces that have been rolled in the rolling mill 2 are cooled in the air-cooled state until they enter the cooling means 3 or until they reach the water-cooled cooling bank 12 located at the uppermost stream in the cooling means 3 (A in the figure). ).
The coil piece that has reached the cooling bank 12 in the water-cooled state passes through the cooling bank 12 and reaches the cooling bank 12 [N] located on the most downstream side of the cooling means 3 under the condition of a constant cooling rate (B in the figure). ). Thereafter, cooling proceeds in an air-cooled state until being wound around the winding device 4 (C in the figure).
Here, “the cooling rate is constant” means that the amount of temperature drop when the rolling material 5 has passed for a fixed time in the cooling means 3 is constant, and the graph showing the plate temperature history in FIG. It is to become.

The plate temperature when water cooling for the coil piece is started is set as the coil piece water injection start temperature, the plate temperature at the end of water cooling is the coil piece water injection end temperature, and the winding temperature is the coil piece target winding temperature. Is set.
As shown in FIG. 2, the material properties of the final rolled material 5 are preferable by cooling the cooling bank 12 in a water-cooled state at a constant cooling rate. However, the setting conditions such as which position of the cooling means 3 is in an air-cooled state, the subsequent water-cooled state, and the number of open valves in the water-cooled cooling bank 12 are set each time. It depends on the required material properties of the rolled material 5. Such setting conditions are calculated based on the flowcharts of FIGS.

First, the rolling material 5 rolled by the rolling mill 2 is sampled at a certain length or every certain time to virtually set a coil piece having a length of about 5 m. Each coil piece is subjected to the following three steps to control cooling of the coil piece.
As shown in FIG. 3, the cooling control process
(i) Step of inputting actual plate temperature, actual plate thickness, actual plate speed on the exit side of the rolling mill 2 (data input step, S31)
(ii) Based on the input data, it is determined whether each cooling bank 12 is in a water-cooled state or an air-cooled state so that the plate temperature in the winding device 4 matches the target temperature (cooling method determination) Process, S32)
(iii) In the cooling bank 12 in a water-cooled state, after calculating the outlet side plate temperature from the inlet side plate temperature so as to satisfy a given cooling rate (a constant value), the number of opened valves that can realize this outlet side plate temperature is calculated. Step of calculating (open valve number determining step, S33)
(iii) A step of controlling the plate temperature of the rolled material 5 by applying the calculated number of open valves to the cooling bank 12 (control step, S34).
The required cooling control (temperature control) of the rolled material 5 is performed by sequentially performing S31 to S34.

In the step S31, the input data is not limited to the actual value, and may be the predicted plate temperature, the predicted plate thickness, and the predicted plate speed obtained using a predetermined prediction model or the like. The predicted plate temperature is the target temperature on the delivery side of the rolling mill 2 set before rolling, and the predicted plate thickness is the target plate thickness on the delivery side of the rolling mill 2 set before rolling, and the predicted plate speed is before rolling. It is the target plate speed on the exit side of the rolling mill 2 set to. For example, when it is set that the plate speed varies based on the speed pattern of the rolled material 5 as shown in FIG. 6, the value obtained from the figure may be used as the predicted plate speed.
Next, the detail of each process of S32-S34 is demonstrated.

FIG. 4 shows details of the cooling method determination step S32. First, the cooling banks 12 [1] to [N-1] of the cooling means 3 are set to the air cooling state, and the cooling bank 12 [N] is set to the water cooling state (S31). In the description, the cooling bank 12 in an air-cooled state may be referred to as an air-cooling bank, and the cooling bank in a water-cooled state may be referred to as a water-cooling bank.
Next, using the input actual sheet temperature T ₀ on the exit side of the rolling mill 2 and the heat transfer formulas shown in the formulas (1) and (2), the rolling mill 2 exit side to the cooling means 3 inlet, with predicted cooling conditions in the cooling bank 12 [1] ~ [N- 1] (the air-cooling state), predicts the entry side temperature T ₁ of the cooling bank 12 [N] (S32).

Specifically, in equation (1), the passage time Δt of the coil piece from the exit side of the rolling mill 2 to the cooling bank 12 [1], the temperature T _x of air (coolant), the heat transfer coefficient α of air, the rolling material 5 The temperature drop amount dT is obtained by substituting the temperature T (= T _o ) and the like, and from this temperature drop amount dT and the actual plate temperature T ₀ on the exit side of the rolling mill 2, the cooling bank 12 [1] Calculate the inlet plate temperature.
Similarly, since the cooling banks 12 [1] to [N-1] are air-cooling banks having zero open valves, the air temperature T _x and the air heat transfer coefficient α are applied to the equation (1). Thus, the plate temperature drop dT in each of the cooling banks 12 [1] to [N-1] is obtained. The number of cooling banks 12 [1] to [N-1] serving as an air cooling bank is n = N-1. Therefore, by using Expression (2), the outlet side plate temperature T ₁ of the cooling bank 12 [N−1], that is, the inlet side plate temperature T _in of the cooling bank 12 [N] in a water-cooled state is obtained.

Next, from the obtained inlet side plate temperature T _{in of} the cooling bank 12 [N] and the temperature drop equation when the cooling rate as shown in Expression (3) is constant, the cooling that is the cooling bank 12 in the water-cooled state is performed. predicting the plate temperature T _out out of the bank 12 [N] (S43).

Furthermore, since the cooling bank 12 [N] is the final cooling bank 12 of the cooling means 3, the rolled material 5 that has passed through this bank is transferred to the downstream side in the air-cooled state and is taken up by the winding device 4. Therefore, in order to predict the winding plate temperature measured by the winding thermometer 13, the winding is performed from the outlet side plate temperature T _{out of} the cooling bank 12 [N] and the cooling bank 12 [N] in Equation (1). passing time up device 4 Delta] t, type the temperature T _x and heat transfer coefficient α of the air (coolant) to determine the amount of temperature drop dT.
By subtracting the amount of temperature drop dT which Motoma' from the side plate temperature T _out out to calculate the winding plate temperature. (S44)
Thereafter, it is determined whether or not the winding plate temperature is equal to the target value. If they are equal, it is found that the setting state of the air cooling bank and the water cooling bank in the cooling bank 12 is appropriate. The input side plate temperature of the bank 12 [N] is determined as T _in and the output side plate temperature is determined as T _out . (S45, S46)
If there is a difference between the winding plate temperature and the target value as a result of the above determination, the air cooling bank on the upstream side is set to the water cooling state (cooling banks 12 [1] to [N-2] are air cooled). The cooling banks 12 [N-1] to [N] are water-cooled), and the process returns to step S42 again to perform calculation. (S47)
Such convergence calculation is performed until the winding plate temperature substantially matches the target value.

FIG. 5 shows details of the open valve number determination step S33.
As shown in this figure, the number of open valves (the number of valves in the open state) in the water-cooled cooling bank 12 is determined by the following procedure.
First, in each water-cooled cooling bank 12, a specific value of the heat transfer coefficient α for changing the inlet side plate temperature T _in to the outlet side plate temperature T _out is used in the calculation of heat transfer for air cooling (1) Calculate using. However, when calculating the heat transfer coefficient α by the equation (1), dT is “entrance side plate temperature T _in −out side plate temperature T _out ”, and the coolant temperature T _x is the temperature of the cooling water. Temperature T of the strip 5 and entrance side temperature T _in. (S51)
The heat transfer coefficient α in the cooling bank 12 in the water-cooled state and the number B of open valves in the cooling bank 12 have a predetermined relationship (for example, B = f (α) depending on the configuration of the cooling unit 3 and the arrangement state of the coolant spray). ) Has been clarified as a result of the field. Therefore, from this relationship and the equation (1) in the water-cooled state, the number of open valves B that realizes the heat transfer coefficient α can be easily obtained, and this number of open valves B is sent to the valve opening / closing signal output unit 16 for cooling. The valve of the means 3 is controlled. (S52)

The heat transfer rate α is obtained again using the number B of open valves thus obtained, and the outlet side plate temperature T _out of the cooling bank 12 is obtained again using the heat transfer rate α. Plate out was determined temperature T _out is to be adopted as the entrance side temperature T _in the cooling bank 12 located one downstream. (S53)
FIG. 7 is a diagram showing the transition of the plate temperature when the cooling means 3 is controlled using the number of open valves determined by the method described above. A broken line is a target cooling rate, and a solid line is a graph showing an actual temperature transition. The two-dot chain line is the result of a conventional method that does not perform cooling control. As can be seen from this figure, the temperature transition indicated by the solid line almost coincides with the broken line. Therefore, by using this winding temperature control method, the rolled material 5 rolled by the rolling mill 2 can be cooled so that the cooling rate is constant and the winding plate temperature matches the target value. By doing so, the material quality of the rolling material 5 can be made high-quality according to the user's request.

[Second Embodiment]
Hereinafter, 2nd Embodiment of the winding temperature control method of the rolling material concerning this invention is described.
In the first embodiment, it is assumed that the plate speed, that is, the coil piece transfer speed varies according to the acceleration / deceleration pattern as shown in FIG. Therefore, the predicted plate speed in the transfer line is obtained according to this fluctuation pattern, the bank passage time and the outlet side plate temperature of the cooling bank 12 are calculated from the predicted values, and the number of open valves is finally determined.
However, actually, the predicted value and the actual value of the plate speed are often different due to various disturbances. In that case, the plate speed is measured for each coil piece (the plate speed is sampled and measured every certain time), and the cooling bank passage time obtained from the actual speed is applied to the equations (1) and (3), The outlet side plate temperature of the cooling bank 12 may be calculated. By doing so, it is possible to obtain a more accurate outlet side plate temperature and to know the exact number of open valves. As a result, a high-quality rolled material 5 can be produced.

For example, it is assumed that the length of the coil piece of the rolled material 5 is substantially the same as that of the cooling bank 12 and the actual plate speed is measured for each coil piece.
As shown in FIG. 8, the target value of the plate temperature history that is initially set for a certain coil piece is indicated by a two-dot chain line. When the coil piece passes through the first water-cooled cooling bank 12, the actual plate speed of the coil piece is measured using the exit side plate speed detector 8 of the rolling mill 2, and the actual value and the equations (1) to (1) to Based on equation (3), the outlet side plate temperature of the first cooling bank 12 is calculated. At this time, the values of variables other than the plate speed are not changed.

As a result of obtaining the actual plate speed, in the case of FIG. 8, since the actual plate speed was larger than the predicted plate speed, the time for performing the water cooling is shortened, and the outlet side plate temperature of the cooling bank 12 [1] is initially set. It is higher than the value. In this case, by using the outlet side plate temperature of the cooling bank 12 [1] calculated based on the actual plate speed, the cooling bank 12 located on the downstream side of the cooling bank 12 [1] is air-cooled or water-cooled. The number of opened valves is calculated again according to the procedure of the first embodiment if it is in the state or in the water-cooled state.
9 and 10 show the results when the outlet side plate temperature of the cooling bank 12 in the water-cooled state is calculated based on the actual speed, FIG. 9 shows the speed history of the rolled material 5, and FIG. 10 shows the plate of the rolled material 5. It is a temperature history.

As can be seen from FIG. 9, the predicted value and the actual value of the plate speed are slightly different at most positions while the coil piece is transferred from the rolling mill 2 to the winding device 4. The significance of reflecting this difference in cooling control is great.
In FIG. 10, the solid line is the plate temperature history of the coil piece when the number of open valves is corrected based on the actual plate speed, and the two-dot chain line is the plate temperature history when the valve is not corrected. If the valve correction is not performed, both the cooling rate and the coiling temperature will deviate from the target values. However, if the valve correction is performed, it is apparent that both the cooling rate and the coiling temperature can be controlled as intended.
Since there is no significant difference between the present embodiment and the first embodiment regarding the configuration, the winding temperature control method, and the operational effects that have not been described above, the description thereof will be omitted.

[Third Embodiment]
Hereinafter, a third embodiment of the rolling material winding temperature control method according to the present invention will be described.
This embodiment is different from the first embodiment in that the cooling bank 12 on the upstream side of the cooling means 3 is in a water-cooled state and the cooling bank 12 on the downstream side is in an air-cooled state.
Other points are substantially the same as those of the first embodiment. The configuration of the continuous rolling device 1 is substantially the same as that of the first embodiment, as shown in FIG. For example, the concept of the cooling method determining step S32 is substantially the same.
FIG. 11 shows a flowchart of the cooling method determination process in the present embodiment.
First, only the cooling bank 12 [1] located on the most upstream side of the cooling means 3 is in a water-cooled state, and the cooling banks 12 [2] to [N] are in an air-cooled state. (S1101)

Using the entered actual sheet temperature T ₀ on the exit side of the rolling mill 2 and the heat transfer formulas shown in the formulas (1) and (2), the rolling mill 2 exit side to the inlet of the cooling means 3 are used. While predicting the cooling state (air cooling state), the inlet side plate temperature T ₁ of the cooling bank 12 [1] is predicted. (S1102)
The entering-side plate temperature T _1, determined from the temperature-fall in a case where the cooling rate is constant (equation (3)), the side plate temperature T _out out of the cooling bank 12 [1] of the water-cooled state. (S1103)
Based on the side plate temperature T _out out of the cooling bank 12 [1] obtained by using the equation (1) and (2) in the air cooling condition, a cooling state cooling bank 12 [2] ~ [N ] And the winding temperature is calculated. (S1104)
Next, it is determined whether or not the calculated winding plate temperature is equal to the target value. If they are equal, the cooling bank 12 [1] is water-cooled according to the calculation result, and the cooling banks 12 [2] to [N]. Is set to an air-cooled state, and the inlet side plate temperature T _in and the outlet side plate temperature of the water-cooled cooling bank 12 are determined as T _out . (S1105, S1106)

If there is a difference between the winding plate temperature and the target value as a result of the determination, the cooling bank 12 [2] on the downstream side is set in the water-cooled state (the cooling bank 12 in the water-cooled state is increased by one). Returning to step S1102 again, calculation is performed (S56).
By performing the above-described repetitive calculation (convergence calculation), the cooling banks 12 [1] to [a] of the cooling means 3 are in the water-cooled state and the cooling banks 12 [a + 1] to [N] are in the air-cooled state. It turns out that it is good (however, 1 <a <N), so that the cooling means 3 can be controlled so that the winding plate temperature matches the target value.
Based on the result of the cooling method determination step S32 described above, the number of opening valves determination step S33 and the control step S34 are performed.

[Fourth Embodiment]
Next, a fourth embodiment of the rolling material winding temperature control method according to the present invention will be described.
As shown in FIG. 12, the present embodiment is different from the first embodiment in that the cooling means 3 includes a first cooling means 3A including a plurality of cooling banks 12, and a plurality of cooling banks provided downstream thereof. 12 is provided with a second cooling zone means 3B having 12 and an intermediate thermometer 20 is disposed between the first cooling means 3A and the second cooling means 3B.

  Also for the cooling means 3, the cooling banks 12 of the first cooling means 3A and the second cooling zone means 3B (cooling means 3) are air-cooled or water-cooled by the method described in the first to third embodiments. Can be set to any of the states. However, in order to increase the accuracy of the cooling control, the first cooling means 3A has a plate temperature on the outlet side of the rolling mill 2 as the inlet side temperature, and a target plate temperature at the intermediate thermometer 20 position as the outlet side temperature. It is determined whether the cooling bank 12 constituting one cooling means 3A is in an air cooling state or a water cooling state. Similarly, with respect to the second cooling means 3B, the cooling plate 12 constituting the second cooling means 3B is set with the target plate temperature at the intermediate thermometer 20 position as the inlet side temperature and the target value of the winding temperature as the outlet side temperature. Decide whether to cool in air or water. Thereafter, the number of open valves that can realize the outlet side plate temperature of the cooling bank 12 that is water-cooled may be determined in the open valve number determination step S33.

  FIG. 13 shows a plate temperature history when the method for controlling the winding temperature of the rolled material 5 according to the present embodiment is performed. A broken line is a target plate temperature history (a constant cooling rate), and a solid line is a plate temperature history of the rolled material 5 that is actually controlled. A two-dot chain line is a plate temperature history diagram of the coil piece when the cooling control is not performed. As can be seen from this figure, unless the valve is corrected, the rolling material 5 having the optimum material quality cannot be produced unlike the target cooling rate. On the other hand, when the valve is corrected, both the cooling rate and the coiling temperature can be controlled as desired, and the rolled material 5 can be appropriately cooled.

  When performing the above cooling control, if the feed plate control is performed on the second cooling means 3B using the actual plate temperature obtained by the intermediate thermometer 20 as an input value, a very preferable result can be obtained. That is, the actual value of the plate temperature is measured using the intermediate thermometer 20, and based on this actual value, the “cooling method determination step S32”, “open” adopted in the first embodiment for the second cooling means 3B, The valve number determining step S33 "is applied again, and the cooling bank 12 disposed downstream of the intermediate thermometer 20 is reset to either the air-cooled state or the water-cooled state, so that the winding temperature of the rolled material 5 is highly accurate. It is good to control.

  Specifically, when the rolled material 5 is being rolled, the intermediate thermometer 20 measures the actual value of the intermediate plate temperature. When there is a difference between the actual value and the target value, the second cooling means 3B is cooled by the second cooling means 3B so as to eliminate the temperature difference at the second cooling means 3B located downstream from the intermediate thermometer. Change the air cooling state. That is, while adopting the actual value of the intermediate plate temperature as the inlet side temperature of the second cooling means 3B, the actual value or predicted value of the plate thickness on the outlet side of the rolling mill 2, the actual value of the plate speed on the outlet side of the rolling mill 2, By performing the cooling method determination step S32 again using the predicted value, the cooling bank 12 of the second cooling means 3B is reset to either the air cooling state or the water cooling state. Thereafter, the number of open valves that can realize the outlet side plate temperature of the cooling bank 12 in a water-cooled state is calculated by performing the open valve number determining step S33 again.

FIG. 14 shows a plate temperature history of the rolled material 5 when the feedforward cooling control of the present embodiment is performed. Until the coil piece reaches the position of the intermediate thermometer 20, the rolled material 5 is cooled based on the initially set plate temperature history. However, the second cooling is performed based on the actual plate temperature by the intermediate thermometer 20. It is clear that the plate temperature history of the means 3B is reset as indicated by a two-dot chain line.
FIG. 15 shows the result of re-determining the number of open valves in the second cooling means 3B and performing the winding temperature control method so that the plate temperature history reset as shown by the two-dot chain line in FIG. 14 can be realized. It is shown. The broken line is the sheet temperature history (target cooling rate) after resetting, and the solid line is the sheet temperature history of the rolled material 5 that is actually controlled. Both of them almost coincided with each other, and as a result, it was possible to reliably match the winding plate temperature with the target value, and as a result, it became possible to produce a rolled material 5 having very good material quality and mechanical characteristics. The two-dot chain line is a plate temperature history diagram when cooling control is not performed.

The present invention is not limited to the above embodiment.
That is, the technique according to the present invention is not applied only to cooling of a thin steel plate or the like, and can be applied to cooling a thick steel plate, for example.
In addition, the rolling material winding temperature control method according to the present invention may be performed in real time in the control unit 15, and is preliminarily calculated on the basis of various conditions offline to create a database, based on this database. The cooling means 3 may be controlled.
The cooling means 3 is provided with a plurality of intermediate thermometers 20, and based on the actual values of the intermediate thermometers 20, 20,..., Cooling provided downstream from the intermediate thermometers 20, 20. The bank 12 may be reset to either the air-cooled state or the water-cooled state, and the winding temperature may be controlled.

It is the figure which showed the apparatus structure (1st Embodiment). It is the figure which showed the prediction history of board temperature. It is the flowchart which showed the winding temperature control method of a rolling material. It is a flowchart of a cooling system determination process. It is a flowchart of an open valve number determination process. It is the figure which showed the prediction history of board speed. It is the figure which showed the board temperature log | history at the time of performing cooling control (1st Embodiment). It is a figure which shows having reset the plate temperature log | history using the performance board speed (2nd Embodiment). It is the figure which showed the performance log | history of board speed (2nd Embodiment). It is the figure which showed the board temperature history at the time of cooling control aiming at the board temperature history of FIG. 8 (2nd Embodiment). It is the figure which showed the flowchart of the cooling system determination process (3rd Embodiment). It is the figure which showed the apparatus structure (4th Embodiment). It is the figure which showed the board temperature log | history at the time of performing cooling control (4th Embodiment). It is a figure which shows resetting a board temperature history using the performance board temperature in an intermediate thermometer (4th Embodiment). It is the figure which showed the board temperature history at the time of cooling control aiming at the board temperature history of FIG. 14 (4th Embodiment).

Explanation of symbols

1 Continuous rolling device 2 Rolling mill (final rolling mill)
DESCRIPTION OF SYMBOLS 3 Cooling means 4 Winding device 5 Rolled material 8 Delivery side plate speed detector 9 Delivery side plate thermometer 10 Delivery side plate thickness meter 12 Cooling bank 13 Winding thermometer 15 Control part 20 Intermediate thermometer

Claims (10)

In the rolling material winding temperature control method for controlling the winding temperature of the rolled material by cooling the rolled material after finish rolling by water cooling or air cooling,
Air-cooled heat transfer calculation is performed on the air-cooled rolled material, and water-cooled heat transfer calculation is performed on the water-cooled rolled material to calculate a predicted value of the winding temperature of the rolled material. ,
A winding temperature control method for a rolled material, wherein the winding temperature is controlled based on the predicted value. Cooling of the rolled material is performed using a cooling means including a plurality of cooling banks that can be operated in a cooling capacity and can be in an air-cooled state,
In the air-cooled cooling bank, the air-cooled heat transfer calculation is performed on the rolled material, and in the water-cooled cooling bank, the water-cooled heat transfer calculation is performed on the rolled material under a constant cooling rate. Calculate the predicted temperature,
The rolling material winding temperature control method according to claim 1, wherein each cooling bank is set to either an air cooling state or a water cooling state based on the predicted value, and the winding temperature is controlled. Set a plurality of coil pieces obtained by sampling at a certain length or time for the rolled material,
(i) For each coil piece, the temperature up to the inlet side of the cooling bank in the uppermost stream of the cooling means by performing air-cooling heat transfer calculation using the plate temperature, plate thickness and plate speed after finish rolling. Calculate the descent
(ii) Assuming that only the cooling bank located at the uppermost stream is in a water-cooled state, after calculating the predicted value of the coil piece winding temperature,
(iii) Calculate the predicted value of the coiling temperature by increasing the cooling bank in the water-cooled state from the upstream side to the downstream side of the cooling means,
(iv) The rolling material winding temperature control method according to claim 2, wherein the number of cooling banks in a water-cooled state when the predicted value matches or approaches a target value is applied to the cooling means. Set a plurality of coil pieces obtained by sampling at a certain length or time for the rolled material,
(i) For each coil piece, the temperature up to the cooling bank inlet side located on the most downstream side of the cooling means by performing air-cooling heat transfer calculation using the plate temperature, plate thickness and plate speed after finish rolling. Calculate the descent
(ii) Assuming that only the cooling bank located at the most downstream side is in a water-cooled state, after calculating a predicted value of the coiling coil winding temperature,
(iii) Increase the cooling bank in the water-cooled state from the downstream side to the upstream side of the cooling means to calculate the predicted value of the winding temperature,
(iv) The rolling material winding temperature control method according to claim 2, wherein the number of cooling banks in a water-cooled state when the predicted value matches or approaches a target value is applied to the cooling means. Measure the actual value of the plate temperature using one or more intermediate thermometers installed in the middle position of the cooling means,
The cooling bank disposed downstream from the intermediate thermometer is set to either an air-cooled state or a water-cooled state based on the actual value, and the winding temperature is controlled. A method for controlling a winding temperature of the rolled material according to any one of the above.   In the cooling bank set in the water-cooled state, the outlet side plate temperature of the cooling bank is set so that the cooling rate is constant, and the number of open valves is determined so as to satisfy the set outlet side plate temperature, 6. The rolling material winding temperature control method according to claim 2, wherein the determined number of open valves is applied to the cooling bank.   In the cooling bank set in the water-cooled state, the transport speed of the rolled material is measured, and the amount of decrease in the plate temperature at the cooling bank is calculated using the measured rate, and the output is based on the amount of decrease in the plate temperature. 6. The rolling material winding temperature control method according to claim 2, wherein the side plate temperature is calculated, and the number of open valves is determined based on the calculated outlet side plate temperature. The plate temperature after the finish rolling is measured with a plate thermometer provided on the exit side of the finish rolling mill,
The plate thickness after the finish rolling is measured with a plate thickness meter provided on the exit side of the finish rolling mill,
8. The rolling material winding temperature control method according to claim 3, wherein the plate speed after the finish rolling is measured by a speed detector provided in a finish rolling mill.   The rolling temperature control method for rolled material according to any one of claims 3 to 7, wherein predicted values set before rolling are used for the plate temperature, the plate thickness, and the plate speed after the finish rolling, respectively. A rolling mill for rolling the rolled material;
A winding device for winding the rolled material rolled by the rolling mill;
A cooling means that is disposed between the rolling mill and the winding device and includes a plurality of cooling banks that can be operated in a cooling capacity and can be in an air-cooled state;
In the air-cooled cooling bank, the air-cooled heat transfer calculation is performed on the rolled material, and in the water-cooled cooling bank, the water-cooled heat transfer calculation is performed on the rolled material under a constant cooling rate. Calculate a predicted value of temperature, and based on the predicted value, each cooling bank is set to either an air-cooled state or a water-cooled state, and a control unit that controls the winding temperature;
A rolling apparatus comprising:

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