JP2001300613A - Method for setting up hot finishing mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setup method which is excellent in the setup accuracy of the screw-down location of a finishing mill and rotational speed of rolls or the setup accuracy of the controlled variable of the profile of a material to be rolled in the case that a heating device is provided before the finishing mill of hot rolling equipment. SOLUTION: The setup calculation of the finishing mill is performed using any of the surface temperature of a rough rolled stock on the outlet side of the heating device, the average temperature on the inlet side of finishing mill calculated from that temperature and the average temperature on the inlet side of the finishing mill calculated from the surface temperature on the inlet side of the heating device. The setup of the finishing mill is preferentially decided and feed forward control may be carried out the setting of the heating pattern of the heating device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting up a hot finishing mill having a step of reheating a material between a rough rolling mill and a finishing mill.

[0002]

2. Description of the Related Art FIG. 1 is an apparatus configuration diagram for explaining a setup method of a finishing mill in a general hot rolling facility. In the figure, reference numeral 1 denotes a rough rolling mill, 2 denotes a finishing rolling mill, 3 denotes a thermometer on the input side of a finishing rolling mill, 4 denotes a reduction device,
Is a roll drive motor, 6 is a rolled material profile control actuator, 7 is a descaler, 8 is a coarse rolled material, 10 is a rolling condition setting device, 11 is a setup device of a conventional finishing mill, 12 is a rolling position setting device, 13 is a roll rotation speed setting device, and 14 is a rolled material profile control amount setting device.

[0003] In a normal hot rolling facility in which the rough rolled material 8 is roughly rolled by the rough rolling mill 1 and then finish rolled by the finish rolling mill 2 comprising a plurality of stands arranged in tandem, the rough rolled material is finish rolled. Before passing through the rolling mill, the roll rolling position, roll speed, etc. of each stand of the finishing mill are set up in advance. That is, AGC during rolling
(Automatic Gauge Control) Thickness control is performed by feedback control using a device and a thickness gauge on the exit side of the finishing mill. However, since feedback control cannot be performed on the leading end of the material to be rolled, The setup taking into account the plastic properties and the elastic properties of the rolling mill is performed.
As a result, it is possible to obtain predetermined thickness accuracy or thickness distribution (hereinafter referred to as profile) accuracy in the plate width direction from the tip end.

In this set-up, as shown in FIG. 1, the surface temperature of the leading end of the rough rolling material 8 is detected by a finishing rolling mill entry side thermometer 3 provided on the entry side of the finishing rolling mill 2,
On the basis of the detected surface temperature and the rolling conditions set in advance by the rolling condition setting device 10, the setup device 11 of the finishing mill determines the initial setting values of the rolling position and the roll rotation speed of each stand, and the rolling position setting device. 12. Output to the roll rotation speed setting device 13. Further, when specifications relating to the product profile such as the crown and edge drop of the material to be rolled and the shape of the finishing mill are determined, the initial set value of the material to be rolled profile control is determined, and the material to be rolled profile control amount is determined. Output to setting device 14.

On the basis of these output results, the rolling position is set by the rolling device 4 of each stand, the roll rotation speed is set by the roll drive motor 5, and the roll profile control amount is set by the roll profile control actuator 6. You. The rolled material profile control amount setting device 14 is a general term for devices that control the thickness distribution in the width direction of the metal strip, such as a roll bender, a variable crown roll, a roll shift device, or a pair cross device.

FIG. 1 shows a setup apparatus 11 for a finishing mill.
The operation of will be described. The temperature Ts detected by the thermometer 3 provided on the entrance side of the finishing mill is used as an initial value for calculating the temperature of the material to be rolled in the finishing mill. That is,

[0007]

(Equation 1) T (f, x): time t, temperature of the material to be rolled at the position x in the thickness direction, f0: time when the leading end of the material to be rolled passes through the thermometer, Ts: measured value of the surface temperature of the material to be rolled, xs: Xc: coordinates corresponding to the center in the thickness direction of the material to be rolled, ΔT: difference between the surface temperature and the center temperature in the thickness direction of the material to be rolled. .

FIG. 2 is a graph showing an example of the temperature distribution in the thickness direction of the material to be rolled.

Here, ΔT is calculated from the temperature of the rough rolled material 8 when a heating furnace (not shown in FIG. 1) installed on the entrance side of the rough rolling mill 1 is extracted, Calculation may be made taking into account the temperature rise due to processing, the cooling due to the contact with the rolls, and the temperature drop due to the cooling in the atmosphere from the rough rolling mill 1 to the finishing thermometer 3 on the entry side thermometer 3, or use an empirical constant value. Have decided. In any case, on the entrance side of the finishing mill 2, the surface of the rolled material is cooled to a lower temperature than the center portion for cooling by contact between the rough rolled material 8 and the rolls of the rough roll and heat radiation into the air. Obviously. That is, ΔT> 0.

Rough rolled material 8 after the thermometer 3 on the entrance side of the finishing mill
Is determined by solving the following heat conduction equation (2) under the boundary condition (3) on the surface of the rolled material (position xs in the thickness direction).

[0011]

(Equation 2) c: specific heat of the rough rolled material, ρ: density of the rough rolled material, λ: thermal conductivity of the rough rolled material, Q (t): unit time at time t, heat input per unit volume, q (t): time Heat release per unit time and unit volume at t.

Here, the heat input amount Q (t) to the rough rolled material and the heat release amount q (t) from the rough rolled material are determined by the rolling condition setting device 1.
The estimated value at the time t when the leading end of the rough rolled material passes is used based on the passing speed set in advance by 0, the amount of water used by the descaler 7, the target thickness of the material to be rolled at each stand, and the like.

Next, at the stage when the rough rolled material 8 is passed through the finishing mill, the leading end of the material to be rolled is assumed to reach the i-th stand of the finishing mill 2 at the time ti. For example, by averaging the temperature distribution in the thickness direction from the temperature T (ti, x), the average temperature Ti of the rolled material in each stand is calculated, and the deformation resistance is calculated based on the average.

As an equation for calculating the deformation resistance in hot rolling, the following equation is widely known.

[0015]

(Equation 3) Kfmi: Deformation resistance of the material to be rolled at the i-th stand εi: Strain of the material to be rolled at the i-th stand υi: Strain rate of the material to be rolled at the i-th stand Ti: Temperature of the material to be rolled at the i-th stand A, B: Here, ε and υ can be determined from the target thickness and the passing speed of each stand in the finishing mill given in advance.

Further, from the deformation resistance Kfmi, (5) and (6)
The rolling load and the advance ratio at each stand are calculated by the formulas.

[0017]

(Equation 4) Pi: the rolling load of the material to be rolled on the i-th stand; fi: the advance rate of the material to be rolled on the i-th stand; Kfmi: the deformation resistance of the material to be rolled on the i-th stand; R'i: the work roll on the i-th stand Flat roll radius, Hi: incoming thickness of rolled material at i-th stand, hi: outlet thickness of rolled material at i-th stand, Qpi: rolling force function of rolled material at i-th stand, φi: Neutral angle of the material to be rolled in the i-th stand, Bi: width of the material to be rolled in the i-th stand.

Here, the thickness and width on the entry and exit sides of the rolled material are given in advance by the rolling condition setting device 10, and the rolling force function Qpi and the neutral angle φi can be solved by an approximate rolling theory model proposed by Sims, for example. Are known.

Further, the flat roll radius Ri 'is, for example, expressed by (7)
(5) to derive the Hitchcock equation and the rolling load
It can be obtained by simultaneous equations.

[0020]

(Equation 5) Ri: work roll radius at the i-th stand, C: constant.

Next, based on the gauge meter formula expressed by the formula (8), the roll-down position of each stand is determined, and (9)
As represented by the equation, the roll rotation speed is determined to maintain the mass flow balance of each stand (volume speed of each stand is constant).

[0022]

(Equation 6) Si: Roll-down position of the i-th stand Mi: Mill rigidity coefficient of the i-th stand S0i: Zero-point correction value of the roll-down zero of the i-th stand

[0023]

(Equation 7) Ni: rotation speed of the roll drive motor of the i-th stand hF: target product thickness (outlet thickness of the last stand) VF: product target threading speed (outlet speed of the last stand) Gri: roll drive of the i-th stand Gear ratio between the motor and the roll If the specifications related to the product profile such as crown or edge drop of the rolled material or the shape of the finishing mill are determined, based on the rolling load calculated by the above formula (5),
For example, a known document (“Plate profile and flatness control in hot strip mill”, Iron and Steel, Vol. 74, No. 7, p. 14)
02-1409. An initial set value of the rolled material profile control amount is determined by a method described in, for example, known document 1).

In recent years, there has been a tendency to produce hot-rolled steel sheets as thin as cold-rolled steel sheets for the purpose of reducing costs when using steel sheets. It may be too low to exceed the load-bearing limit of the finishing mill or adversely affect the material properties of the rolled material. For this reason, a technique is used in which a heating device is provided between the rough rolling mill and the finish rolling mill, and the temperature of the rolled material is raised to the target temperature required for protection of the finishing rolling mill and material characteristics at the entrance of the finish rolling mill. It has come to be.

However, the conventional method of setting up a finishing mill does not consider such a temperature change due to the influence of the heating device, and thus causes a problem.

FIG. 3 is a schematic graph showing an example of a temperature change of a rolled material before and after passing through a heating device. As shown in the drawing, immediately after passing through the heating device, the temperature on the surface becomes higher than that on the center of the rough rolled material. For this reason, sufficient setup accuracy cannot be obtained with the conventional setup method that only considers heat radiation to the atmosphere as a temperature change from the exit side of the rough rolling mill to the thermometer on the finishing side, and the dimensional accuracy of the material to be rolled is reduced. .

[0027]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for setting up a rolling position and a roll rotation speed of a finishing mill or a material to be rolled when a heating device is provided between a rough rolling mill and a finishing mill. It is an object of the present invention to provide a method of setting up a hot finish rolling mill with good setup accuracy of a profile control amount.

[0028]

The present inventors have obtained the following findings through various simulations and experiments.

(A) Conventionally, in equipment without a heating device,
When the temperature at the tip end of the material to be rolled on the entrance side of the finish rolling mill is used for the setup calculation, a method of calculating the average temperature in consideration of the temperature distribution in the thickness direction is used to obtain the average deformation resistance of the material to be rolled. The average temperature can be obtained by measuring the surface temperature on the entrance side of the finishing mill and performing calculations based on the above equations (2) and (3).

However, as shown in FIG. 3, since the surface temperature of the rough rolled material is higher than the center temperature, the process control method without a heating device cannot be used as it is. As a countermeasure, when the heating pattern of the heating device is approximately constant and the transport condition of the coarsely-rolled material from the heating device to the finishing mill is constant, the surface temperature of the rough-rolled material on the entrance side or the exit side of the heating device is reduced. The temperature at the finishing mill entry side can be estimated from the measured values and the constants or constants found from a constant table from the measured values.

(B) In estimating the temperature at the entrance of the finishing mill at the leading end of the rough rolled material, as described above, a method of estimating from the temperature measured at the entrance or exit of the heating device using a constant is used for all methods. In this case, the temperature estimation error may increase. In that case, the temperature distribution in the thickness direction of the rough rolled material on the exit side of the heating device or on the entrance side of the finishing mill, based on the measured value of the heating device inlet side temperature or the measured value of the heating device outlet side temperature and the heating pattern of the heating device. Is desirably determined by heat transfer calculation or the like.

(C) Conventionally, in the case of a setup method without a heating device, a setup calculation is started after measuring a material to be rolled on the entrance side of the finish rolling mill, and after obtaining the result, the rolling position of each stand and the like are determined. Determine the initial settings. Since the setup calculation requires a considerable amount of calculation time, there is little time allowance between the temperature measurement and the start of the sheet passing. Therefore, in some cases, it is necessary to delay the start of the sheet passing. On the other hand, when there is a heating device, it is possible to control the temperature of the material to be rolled on the finishing input side to a predetermined value. Therefore, the setup calculation of the finishing mill is performed in advance by assuming the temperature of the material to be rolled on the entrance side of the finishing mill, and if the heating device is controlled so that the estimated value is attained, the time for the setup calculation is not sufficient. Is eliminated.

The present invention has been completed based on the above findings, and the gist thereof is as follows.

(1) A method for setting up a hot finishing rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, the method comprising the steps of: Estimating the temperature, estimating the tip temperature at the finishing mill input side from the estimated value of the tip temperature, the estimated value of the tip temperature at the finishing mill input side and the rolling conditions of the finishing mill set in advance, and Estimate the temperature of the material to be rolled at each stand of the finishing mill based on the, to determine the initial setting value of the rolling position and roll rotation speed of each stand of the finishing mill based on the estimated material temperature to be rolled. How to set up a hot finishing mill.

(2) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, wherein a tip portion of a rough rolled material heated by the heating device is provided. Estimating the temperature, estimating the tip temperature at the finishing mill input side from the estimated value of the tip temperature, the estimated value of the tip temperature at the finishing mill input side and the rolling conditions of the finishing mill set in advance, and Estimate the temperature of the material to be rolled at each stand of the finishing mill based on the, based on the estimated material temperature to be rolled, to determine the initial setting value of the rolling material profile control amount of each stand of the finishing mill based on the estimated rolling material temperature How to set up a hot finishing mill.

(3) The method according to the above (1) or (2), wherein the measured value of the surface temperature at the exit side of the heating device is used as the estimated value of the temperature at the tip of the rough rolled material after heating. How to set up a finishing mill.

(4) As the estimated value of the temperature at the tip of the rough-rolled material after heating, the surface temperature measured value at the tip of the rough-rolled material on the inlet side or the outlet side of the heating device, the material and dimensions of the rough-rolled material, and the heating (1) or characterized by using a temperature distribution in the thickness direction of the rough rolled material calculated based on the heating pattern of the apparatus or
(2) The method for setting up a hot finishing mill as described in the item (2).

(5) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between the rough rolling mill and the finish rolling mill, the method comprising: Assuming, the estimated material temperature at each stand of the finishing mill based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, each of the finishing mills based on the rolling material temperature Determine the initial setting value of the rolling position and the roll rotation speed of the stand, and calculate the forward end temperature of the entrance side of the finishing rolling mill from the assumed value of the tip temperature of the rough rolling material on the entrance side of the finishing rolling machine, A hot finish rolling mill characterized by setting a heating pattern of a heating device based on a measured value of a tip surface temperature of a rough rolled material on a heating device entrance side so as to obtain a backward calculated value of the tip temperature. Setup method.

(6) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between the rough rolling mill and the finish rolling mill, comprising: Assuming, the material temperature at each stand of the finishing mill is estimated based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, and each stand of the finishing mill is estimated based on the material temperature. Determine the initial setting value of the rolling position and the roll rotation speed of the rolling mill, and calculate the forward end temperature of the entrance side of the finishing rolling mill from the assumed value of the leading end temperature of the rough rolling material on the entrance side of the finishing rolling mill. Setting up a heating pattern of the heating device based on the measured value of the surface temperature of the tip portion of the rough rolled material on the inlet side of the heating device so that a backward calculated value of the tip temperature can be obtained; Method.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 is an apparatus configuration diagram for explaining a method for setting up a hot finishing mill according to the present invention.

A method of setting up by measuring the surface temperature of the rough rolled material on the exit side of the heating device will be described with reference to the device configuration diagram of FIG. 1 are denoted by the same reference numerals. The rough rolled material is roughly rolled by the rough rolling mill 1, and then
After the rough rolled material 8 is heated by the heating device 20, the finish rolled by the finish rolling mill 2 including a plurality of stands arranged in tandem, and the rough rolled material 8 is measured by the thermometer 21 provided on the exit side of the heating device 20. Based on the detected surface temperature and the rolling conditions set in advance by the rolling condition setting device 10, the set-up device 31 of the finishing mill sets the rolling position of each stand and the initial roll rotation speed. Determine the set value, the rolling position setting device 12,
The output is output to the roll rotation number setting device 13. Furthermore, if the product profile such as crown or edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the initial setting value of the material to be rolled profile control amount is determined,
It is output to the rolled material profile control amount setting device 14.
Based on these results, the roll-down position by the roll-down device 4 of each stand, the roll rotation speed by the roll drive motor 5,
A rolled material profile control amount is set by the rolled material profile control actuator 6.

The operation of the setup device 31 of the finishing mill according to the present invention will be described.

The temperature detected by the heating device outlet thermometer 21 provided on the outlet side of the heating device 20 is used as an initial value for calculating the temperature of the rolled material in the finishing mill. That is,

[0044]

(Equation 8) t0: Time when the leading end of the rough rolled material passes through the heating device outlet thermometer 21; Tb0: Measured surface temperature of the rough rolled material; ΔT ': Surface temperature in the thickness direction of the rough rolled material and the central temperature Difference. Here, considering that the surface temperature after heating may be higher than the center as shown in FIG.
A constant value stored in advance or a different parameter is used for each material / dimension of the rough rolled material. For example, ΔT ′ = − 60 ° C. in the heating device having the characteristics shown in FIG.

The temperature of the rolled material after the heating device outlet thermometer 21 is obtained by solving the above-mentioned heat conduction equation (2) under the boundary condition (3) on the surface of the rough rolled material (position xs in the thickness direction). Ask by.

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed and water usage of the descaler 7 which are preset by the rolling condition setting device 10. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, the leading end of the rolled material is the ith of the finishing mill.
From the temperature T (ti, x) of the rolled material at the time ti estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature Ti of the rolled material at each stand is calculated, Based on this, the deformation resistance of each stand is calculated according to equation (4) described above.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated according to the above-mentioned equations (5), (6) and (7).

Next, based on the determined rolling load and advance rate of each stand, the roll-down position and roll rotation speed of each stand are determined according to the equations (8) and (9).

The operation of the setup device 31 of the finishing mill according to the method of setting up the profile control amount of the finishing mill according to the present invention is performed as follows.

When specifications relating to the product profile of the material to be rolled, such as crown and edge drop, and the shape of the finishing mill are determined, the above-described method of determining the rolling position of each stand and the roll rotation speed is used. From the calculated rolling load of each stand, for example, a rolled material profile control amount is determined according to the known document 1.

Next, in the present invention, the operation of the setup device 31 when setting up the finishing mill based on the temperature distribution in the thickness direction of the leading end of the rough rolled material will be described. The device configuration diagram in this case is the same as FIG.

The temperature distribution of the rolled material is estimated based on the following method. As one form of the heating device, when an induction heating device is used, it is known that the amount of heat given to the rolled material from the induction heating device decreases exponentially from the surface in the thickness direction toward the center. I have. That is, the amount of heat Qb (t, x) given from the heating device to the position x in the thickness direction of the rolled material at each time t is estimated based on a heating pattern that is a time transition such as power consumption of the heating device, and the heating is performed. The temperature change of the rolled material inside the device is calculated using the following equation.

[0054]

(Equation 9) Qb (t, x): time t, the amount of heat given from the heating device to the position x in the thickness direction of the rough rolled material, q '(t): heat release per unit time and unit volume at time t.

As a result, the surface temperature T (tb0, xs) and the temperature T (tb0, xc) of the rolled material at the time tb0 at which the leading end of the rolled material is estimated to reach the heating device exit side are obtained. Based on this calculation result, the difference between the surface temperature Tb0 detected by the heating device outlet thermometer 21 and the temperature at the center of the rolled material is estimated. That is, in the formula (10),

[0056]

(Equation 10) Is used as an initial value for calculating the temperature of the rolled material in the finishing mill.

The temperature of the rolled material after the heating device outlet thermometer 21 is obtained by solving the above-mentioned heat conduction equation (2) under the boundary condition (3).

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed preset by the rolling condition setting device 10 and the amount of water used by the descaler 7. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, for example, the temperature distribution in the thickness direction is averaged from the temperature T (ti, x) of the rolled material at the time ti at which the leading end of the rolled material reaches the i-th stand of the finishing mill. In this way, the average temperature Ti of the rolled material at each stand is calculated, and based on this, the deformation resistance of each stand is calculated according to the above equation (4).

After that, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated in accordance with the above equations (5) to (7).

Finally, the rolling position and the roll rotation speed of each stand are determined according to (8) and (9) based on the rolling load and the advance rate of each stand determined.

On the other hand, when the product profile such as the crown and edge drop of the material to be rolled and the specifications regarding the shape of the finishing mill are determined, the rolling load of each stand obtained by the setup calculation of the finishing mill described above is determined. Then, the rolled material profile control amount is determined according to the above-mentioned known document 1.

FIG. 5 is an apparatus configuration diagram for explaining a method of setting up a hot finishing mill having a thermometer on the inlet side of the heating apparatus according to the present invention. 4, the same elements as those in FIG. 4 are denoted by the same reference numerals. In the figure, a thermometer is installed on the input side of the heating device 20.

The rough rolled material 8 is roughly rolled by the rough rolling mill 1, then heated by the heating device 20, and then subjected to finish rolling by the finishing rolling mill 2 comprising a plurality of stands arranged in tandem. The surface temperature of the leading end of the rough rolled material 8 is detected by a heating device inlet-side thermometer 22 provided on the inlet side. This temperature Tbi is used as an initial value for calculating the temperature of the rolled material in the heating device 20 and the finishing mill 2. That is,

[0065]

[Equation 11] T (t, x): time t, rough rolled material temperature at position x in the thickness direction, t0: time when the leading end of the rough rolled material passes through the thermometer on the inlet side of the heating device, Ts: surface temperature measurement of the rough rolled material Value xs: coordinates corresponding to the surface of the coarsely-rolled material in the thickness direction, xc: coordinates corresponding to the center of the coarsely-rolled material in the thickness direction, ΔTb: temperature difference between the surface and the center of the coarsely-rolled material in the thickness direction, And

Here, ΔTb is a temperature change in the roughing mill 1 and a temperature change from the temperature at the time of extracting the heating furnace (not shown) installed on the inlet side of the roughing mill 1 and the temperature from the roughing mill 1 to the inlet of the heating device. The calculation is performed in consideration of a temperature change due to heat radiation up to a total of 22 or an empirical constant value is used for the determination. In any case, it is clear that the surface of the rolled material is lower in temperature than the central part on the inlet side of the heating device due to cooling and heat radiation due to contact between the rough rolled material and the rolling rolls of the rough rolling mill. That is, ΔTb ≧ 0.

Using the rolled material temperature given by equation (14) as an initial value, the temperature change in the heating device is calculated according to the above formulas (11) and (12).
And the temperature change in the finishing mill is calculated according to (2) and (3).

Here, the heat input amounts Q (t) and Qb (t,
x), the heat release amounts q (t) and q ′ (t) from the rolled material are heating patterns and threading speeds, descalers which are time transitions such as power consumption of the heating device preset by the rolling condition setting device 10. The value at time t when the leading end of the rolled material passes is used based on the amount of water used in 7, the target thickness of the rolled material at each stand, and the like.

Next, the leading end of the rolled material is placed on the i-th finishing mill.
From the temperature T (ti, x) of the rolled material at time ti estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature Ti of the rolled material at each stand is calculated. Then, the deformation resistance of each stand is calculated according to the above equation (4) based on the above equation.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio at each stand are calculated according to (5) to (7).

Thereafter, based on the rolling load and the advance rate of each stand obtained, the following (8) and (9)
Determine the rolling position and roll rotation speed of each stand.

On the other hand, when the product profile such as crown and edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the rolling load of each stand obtained by the setup calculation of the finishing mill described above is determined. Then, the rolled material profile control amount is determined according to the above-mentioned known document 1.

In any of the set-up methods of the present invention described above, after measuring the surface temperature of the rough rolled material on the exit side of the heating device, the setup calculation is started or the rough rolling of the rough rolled material on the entrance side of the heating device is started. After measuring the surface temperature of the material, the heat transfer calculation in the heating device is started to set up the rolling position and roll rotation speed of the finishing mill or the controlled amount of the material to be rolled.

The setup calculation requires a considerable amount of calculation time, and may require a large amount of calculation when calculating the temperature change of the rough rolled material by the heating device. If the distance to is short and the threading speed of the rolled material is fast, after detecting the rough rolled material surface temperature,
Sometimes setup is not in time.

As a countermeasure, the present invention provides a setup method for preferentially determining the setup of the finishing mill and adjusting the heating pattern of the heating device.

FIG. 6 is an apparatus configuration diagram for explaining a method of setting up a hot finishing mill by feed-forwarding a heating pattern of a heating apparatus according to the present invention.

In the figure, in order to secure the rolled material temperature in the finish rolling mill due to material property restrictions and the like, the target rolled material temperature on the entrance side of the finish rolling mill is preset by the target temperature setting device 34.

After the rough rolling material 8 is roughly rolled by the rough rolling mill 1 and heated by the heating device 20, when the finish rolling is performed by the finishing rolling mill 2 comprising a plurality of stands arranged in tandem, the entrance side of the heating device 20 Thermometer 22 provided in
Based on the surface temperature of the leading end of the rough rolled material 8 detected in
By feeding forward the heating pattern to the heating device 20, the temperature of the material to be rolled on the entrance side of the finishing mill is controlled to a target temperature given in advance by the target temperature setting device 34, and the material to be rolled on the entrance side of the finishing mill is controlled. Based on the target material temperature and the rolling conditions set in advance by the rolling condition setting device 10, the set-up device 31 of the finishing mill according to the present invention determines the initial setting values of the rolling position and roll rotation speed of each stand, Output to the position setting device 12 and the roll rotation speed setting device 13.

On the other hand, when the product profile such as crown and edge drop of the material to be rolled and the specification regarding the shape of the finishing mill are determined, the initial setting value of the material profile control amount is determined and the material to be rolled is determined. Output to the profile control amount setting device 14. On the basis of these results, the roll-down position, roll drive motor 5
The roll rotation speed and the rolled material profile control amount are set by the rolled material profile control actuator 6.

The control operation of the setup device 31 is as follows. Using the temperature of the rolled material in the finish rolling mill as the initial value of the target temperature on the entrance side of the finish rolling mill, the above-mentioned heat conduction equation (2) is used as the boundary condition (3) on the rolled material surface (thickness direction position xs). Find it by solving with

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed preset by the rolling condition setting device 10 and the amount of water used by the descaler 7. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, the leading end of the rolled material is placed on the i-th finishing mill.
From the temperature T (ti, x) of the rolled material at the time ti estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature Ti of the rolled material at each stand is calculated, Based on this, the deformation resistance of each stand is calculated according to equation (4) described above.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated according to the above-mentioned equations (5) to (7).

Thereafter, based on the determined rolling load and advance rate of each stand, the rolling position and roll rotation speed of each stand are determined in accordance with the equations (8) and (9).

On the other hand, when the product profile such as the crown and edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the finishing mill calculated by the above-mentioned finishing mill set-up device is calculated. From the rolling load of each stand, the rolled material profile control amount is determined according to the known document 1.

[0086]

EXAMPLE A comparative test result by simulation is shown in a hot rolling facility in which a thermometer for detecting the temperature of a rolled material is installed on the outlet side of a heating device and a work roll bender is provided as an actuator for controlling a profile of a material to be rolled. .

Table 1 shows estimated values of the temperature of the rolled material at each stand of the finishing mill as test results when the method of using the surface temperature on the outlet side of the heating device according to the present invention for the setup calculation is applied. The surface temperature on the exit side of the heating device is an actually measured value). Here, F1 to F7 indicate the first to seventh stands of the finishing mill.

[0088]

[Table 1] Table 2 shows the estimated values of the temperature of the rolled material at each stand of the finishing mill as test results when a conventional method using the temperature measurement value at the entrance of the finishing mill for the setup calculation is applied (however, the heating device output Side surface temperature measured value).

[0089]

[Table 2] If the method according to the present invention is applied, on the exit side of the heating device, the rolled material temperature in the finishing mill is calculated by accurately estimating that the temperature of the rolled material central portion is lower than the surface, When the conventional method is applied, since a heating device is not assumed, the temperature of the rolled material in the finishing mill is calculated by erroneously estimating that the temperature at the center of the rolled material is higher than the surface.

Tables 3 and 4 show the differences between the initial setting values of the rolling position and the roll rotation speed determined by the two methods based on the temperature calculation results.

[0091]

[Table 3]

[Table 4] Table 5 shows the deviation of the product thickness (thickness on the exit side of the final stand F7) at the tip when rolling was performed by setting the rolling position and the roll rotation speed to the initial set values in Tables 3 and 4. However, it is understood that deterioration of the dimensional accuracy of the product can be prevented by implementing the present invention.

[0092]

[Table 5] Next, using the surface temperature of the heating device exit side according to the present invention, as a test result when applying a method of setting up the profile control amount of the material to be rolled, the initial setting value of the work roll bender in each stand of the finishing mill Are shown in Table 6.

[0093]

[Table 6] Set the work roll vendor to the initial settings in Table 6,
Table 7 shows the product crown deviation at the leading end when the rolling is performed. It can be seen that the dimensional accuracy of the product can be prevented from deteriorating by implementing the present invention.

[0094]

[Table 7]

According to the present invention, the initial setting of the rolling position and the roll rotation speed of the finishing mill or the control amount of the material to be rolled can be performed with high accuracy in a hot strip mill for a metal strip having a heating device. It is possible to guarantee the dimensional quality of the rolled material tip.

[Brief description of the drawings]

FIG. 1 is an apparatus configuration diagram for explaining a setup method of a finishing mill in a general hot rolling facility.

FIG. 2 is a graph showing an example of a temperature distribution in a thickness direction of a material to be rolled.

FIG. 3 is a schematic graph showing an example of a change in temperature of a rolled material before and after passing through a heating device.

FIG. 4 is an apparatus configuration diagram for describing a setup method of a hot finishing mill according to the present invention.

FIG. 5 is an apparatus configuration diagram for explaining a setup method of a hot finishing mill having a thermometer on an inlet side of a heating apparatus according to the present invention.

FIG. 6 is an apparatus configuration diagram for explaining a setup method of a hot finishing mill by feed-forwarding a heating pattern of a heating apparatus according to the present invention.

[Explanation of symbols]

 1: Rough rolling mill 2: Finishing rolling mill 3: Finishing rolling mill inlet thermometer 4: Rolling-down device 5: Roll drive motor 6: Rolling material profile control actuator 7: Descaler 8: Rough rolling material 10: Rolling condition setting Apparatus 11: Setup apparatus 12: Roll-down position setting apparatus 13: Roll rotation speed setting apparatus 14: Rolled material profile control amount setting apparatus 20: Heating apparatus 21: Heating apparatus outlet thermometer 22: Heating apparatus inlet thermometer 31: Setup device 34: Target temperature setting device

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 21, 2000 (2006.2.
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Setup method of hot finishing mill

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting up a hot finishing mill having a step of reheating a material between a rough rolling mill and a finishing mill.

[0002]

2. Description of the Related Art FIG. 1 is an apparatus configuration diagram for explaining a setup method of a finishing mill in a general hot rolling facility. In the figure, reference numeral 1 denotes a rough rolling mill, 2 denotes a finishing rolling mill, 3 denotes a thermometer on the input side of a finishing rolling mill, 4 denotes a reduction device,
Is a roll drive motor, 6 is a rolled material profile control actuator, 7 is a descaler, 8 is a coarse rolled material, 10 is a rolling condition setting device, 11 is a setup device of a conventional finishing mill, 12 is a rolling position setting device, 13 is a roll rotation speed setting device, and 14 is a rolled material profile control amount setting device.

[0003] In a normal hot rolling facility in which the rough rolled material 8 is roughly rolled by the rough rolling mill 1 and then finish rolled by the finish rolling mill 2 comprising a plurality of stands arranged in tandem, the rough rolled material is finish rolled. Before passing through the rolling mill, the roll rolling position, roll speed, etc. of each stand of the finishing mill are set up in advance. That is, AGC during rolling
(Automatic Gauge Control) Thickness control is performed by feedback control using a device and a thickness gauge on the exit side of the finishing mill. However, since feedback control cannot be performed on the leading end of the material to be rolled, The setup taking into account the plastic properties and the elastic properties of the rolling mill is performed.
As a result, it is possible to obtain predetermined thickness accuracy or thickness distribution (hereinafter referred to as profile) accuracy in the plate width direction from the tip end.

In this set-up, as shown in FIG. 1, the surface temperature of the leading end of the rough rolling material 8 is detected by a finishing rolling mill entry side thermometer 3 provided on the entry side of the finishing rolling mill 2,
On the basis of the detected surface temperature and the rolling conditions set in advance by the rolling condition setting device 10, the setup device 11 of the finishing mill determines the initial setting values of the rolling position and the roll rotation speed of each stand, and the rolling position setting device. 12. Output to the roll rotation speed setting device 13. Further, when specifications relating to the product profile such as the crown and edge drop of the material to be rolled and the shape of the finishing mill are determined, the initial set value of the material to be rolled profile control is determined, and the material to be rolled profile control amount is determined. Output to setting device 14.

On the basis of these output results, the rolling position is set by the rolling device 4 of each stand, the roll rotation speed is set by the roll drive motor 5, and the roll profile control amount is set by the roll profile control actuator 6. You. The rolled material profile control amount setting device 14 is a general term for devices that control the thickness distribution in the width direction of the metal strip, such as a roll bender, a variable crown roll, a roll shift device, or a pair cross device.

FIG. 1 shows a setup apparatus 11 for a finishing mill.
The operation of will be described. Temperature T _s detected by the thermometer 3 provided in the finishing mill entry side is used as the initial value of the temperature calculation of the material to be rolled in the finishing mill. That is,

[0007]

(Equation 1) T (t, x): time t, temperature of the material to be rolled at the position x in the thickness direction, t ₀ : time when the tip of the material to be rolled passes through the thermometer, T _s : measured value of the surface temperature of the material to be rolled, x _s : coordinates corresponding to the surface of the material to be rolled in the thickness direction; x _c : coordinates corresponding to the center of the material to be rolled in the thickness direction; ΔT: surface temperature and center temperature of the material to be rolled in the thickness direction The difference,.

FIG. 2 is a graph showing an example of the temperature distribution in the thickness direction of the material to be rolled.

Here, ΔT is calculated from the temperature of the rough rolled material 8 when a heating furnace (not shown in FIG. 1) installed on the entrance side of the rough rolling mill 1 is extracted, Calculation may be made taking into account the temperature rise due to processing, the cooling due to the contact with the rolls, and the temperature drop due to the cooling in the atmosphere from the rough rolling mill 1 to the finishing thermometer 3 on the entry side thermometer 3, or use an empirical constant value. Have decided. In any case, on the entrance side of the finishing mill 2, the surface of the rolled material is cooled to a lower temperature than the center portion for cooling by contact between the rough rolled material 8 and the rolls of the rough roll and heat radiation into the air. Obviously. That is, ΔT> 0.

Rough rolled material 8 after the thermometer 3 on the entrance side of the finishing mill
Is determined by solving the following heat conduction equation (2) under the boundary condition (3) on the surface of the rolled material (position x _{s in the} thickness direction).

[0011]

(Equation 2) c: specific heat of the rough rolled material, ρ: density of the rough rolled material, λ: thermal conductivity of the rough rolled material, Q (t): unit time at time t, heat input per unit volume, q (t): time Heat release per unit time and unit volume at t.

Here, the heat input amount Q (t) to the rough rolled material and the heat release amount q (t) from the rough rolled material are determined by the rolling condition setting device 1.
The estimated value at the time t when the leading end of the rough rolled material passes is used based on the passing speed set in advance by 0, the amount of water used by the descaler 7, the target thickness of the material to be rolled at each stand, and the like.

Next, at the stage where the rough rolled material 8 is passed through the finishing mill, the material to be rolled at time t _i at which the leading end of the material to be rolled reaches the i-th stand of the finishing mill 2 is estimated. For example, by averaging the temperature distribution in the thickness direction from the temperature T (t _i , x), the average temperature T _i of the rolled material in each stand is calculated, and the deformation resistance is calculated based on this.

As an equation for calculating the deformation resistance in hot rolling, the following equation is widely known.

[0015]

(Equation 3) Kfm _i : Deformation resistance of the material to be rolled at the i-th stand ε _i : Strain of the material to be rolled at the i-th stand υ _i : Strain rate of the material to be rolled at the i-th stand T _i : Temperature of the material to be rolled at the i-th stand A, B: constants Here, ε and υ can be determined from the target thickness and the passing speed of each stand in the finishing mill given in advance.

Further, from the deformation resistance Kfm _i , (5), (6)
The rolling load and the advance ratio at each stand are calculated by the formulas.

[0017]

(Equation 4) P _i: rolling load of the rolling material in the i stands, f _i: forward slip of the rolling material in the i stand, KFM _i: the i-th stand: deformation resistance of the rolled material in the i stand, R _i ' flat roll radius of work roll, H _i: the entry side thickness of the rolled material in the i stand, h _i: exit side thickness of the rolled material in the i stand, Qp _i: the material to be rolled in the i stand Rolling force function, φ _i : neutral angle of the material to be rolled at the i-th stand, B _i : width of the material to be rolled at the i-th stand.

Here, the thickness and width of the rolled material on the inlet and outlet sides are given in advance by the rolling condition setting device 10, and the rolling force function Qp _i and the neutral angle φ _i are solved by an approximate rolling theory model proposed by Sims, for example. It is known.

The flat roll radius R _i ′ is, for example, (7)
(5) to derive the Hitchcock equation and the rolling load
It can be obtained by simultaneous equations.

[0020]

(Equation 5) R _i : work roll radius at the i-th stand, C: constant.

Next, based on the gauge meter formula expressed by the formula (8), the roll-down position of each stand is determined, and (9)
As represented by the equation, the roll rotation speed is determined to maintain the mass flow balance of each stand (volume speed of each stand is constant).

[0022]

(Equation 6) S _i : Roll-down position of the i-th stand M _i : Mill stiffness coefficient of the i-th stand S0 _i : Zero-point correction value of the i-th stand

[0023]

(Equation 7) N _i : Rotation speed of the roll drive motor of the i-th stand h _F : Product target thickness (thickness on the exit side of the last stand) V _F : Product target threading speed (speed on the exit side of the last stand) Gr _i : i-th Gear ratio between the roll drive motor of the stand and the roll If the specifications for the product profile such as crown and edge drop of the rolled material and the shape of the finishing mill are specified, the rolling load calculated by the above formula (5) On the basis of the,
For example, a known document (“Plate profile and flatness control in hot strip mill”, Iron and Steel, Vol. 74, No. 7, p. 14)
02-1409. An initial set value of the rolled material profile control amount is determined by a method described in, for example, known document 1).

In recent years, there has been a tendency to produce hot-rolled steel sheets as thin as cold-rolled steel sheets for the purpose of reducing costs when using steel sheets. It may be too low to exceed the load-bearing limit of the finishing mill or adversely affect the material properties of the rolled material. For this reason, a technique is used in which a heating device is provided between the rough rolling mill and the finish rolling mill, and the temperature of the rolled material is raised to the target temperature required for protection of the finishing rolling mill and material characteristics at the entrance of the finish rolling mill. It has come to be.

However, the conventional method of setting up a finishing mill does not consider such a temperature change due to the influence of the heating device, and thus causes a problem.

FIG. 3 is a schematic graph showing an example of a temperature change of a rolled material before and after passing through a heating device. As shown in the drawing, immediately after passing through the heating device, the temperature on the surface becomes higher than that on the center of the rough rolled material. For this reason, sufficient setup accuracy cannot be obtained with the conventional setup method that only considers heat radiation to the atmosphere as a temperature change from the exit side of the rough rolling mill to the thermometer on the finishing side, and the dimensional accuracy of the material to be rolled is reduced. .

[0027]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for setting up a rolling position and a roll rotation speed of a finishing mill or a material to be rolled when a heating device is provided between a rough rolling mill and a finishing mill. It is an object of the present invention to provide a method of setting up a hot finish rolling mill with good setup accuracy of a profile control amount.

[0028]

The present inventors have obtained the following findings through various simulations and experiments.

(A) Conventionally, in equipment without a heating device,
When the temperature at the tip end of the material to be rolled on the entrance side of the finish rolling mill is used for the setup calculation, a method of calculating the average temperature in consideration of the temperature distribution in the thickness direction is used to obtain the average deformation resistance of the material to be rolled. The average temperature can be obtained by measuring the surface temperature on the entrance side of the finishing mill and performing calculations based on the above equations (2) and (3).

However, as shown in FIG. 3, since the surface temperature of the rough rolled material is higher than the center temperature, the process control method without a heating device cannot be used as it is. As a countermeasure, when the heating pattern of the heating device is approximately constant and the transport condition of the coarsely-rolled material from the heating device to the finishing mill is constant, the surface temperature of the rough-rolled material on the entrance side or the exit side of the heating device is reduced. The temperature at the finishing mill entry side can be estimated from the measured values and the constants or constants found from a constant table from the measured values.

(B) In estimating the temperature at the entrance of the finishing mill at the leading end of the rough rolled material, as described above, a method of estimating from the temperature measured at the entrance or exit of the heating device using a constant is used for all methods. In this case, the temperature estimation error may increase. In that case, the temperature distribution in the thickness direction of the rough rolled material on the exit side of the heating device or on the entrance side of the finishing mill, based on the measured value of the heating device inlet side temperature or the measured value of the heating device outlet side temperature and the heating pattern of the heating device. Is desirably determined by heat transfer calculation or the like.

(C) Conventionally, in the case of a setup method without a heating device, a setup calculation is started after measuring a material to be rolled on the entrance side of the finish rolling mill, and after obtaining the result, the rolling position of each stand and the like are determined. Determine the initial settings. Since the setup calculation requires a considerable amount of calculation time, there is little time allowance between the temperature measurement and the start of the sheet passing. Therefore, in some cases, it is necessary to delay the start of the sheet passing. On the other hand, when there is a heating device, it is possible to control the temperature of the material to be rolled on the finishing input side to a predetermined value. Therefore, the setup calculation of the finishing mill is performed in advance by assuming the temperature of the material to be rolled on the entrance side of the finishing mill, and if the heating device is controlled so that the estimated value is attained, the time for the setup calculation is not sufficient. Is eliminated.

The present invention has been completed based on the above findings, and the gist thereof is as follows.

(1) A method for setting up a hot finishing rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, the method comprising the steps of: Estimating the temperature, estimating the tip temperature at the finishing mill input side from the estimated value of the tip temperature, the estimated value of the tip temperature at the finishing mill input side and the rolling conditions of the finishing mill set in advance, and Estimate the temperature of the material to be rolled at each stand of the finishing mill based on the, to determine the initial setting value of the rolling position and roll rotation speed of each stand of the finishing mill based on the estimated material temperature to be rolled. How to set up a hot finishing mill.

(2) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, wherein a tip portion of a rough rolled material heated by the heating device is provided. Estimating the temperature, estimating the tip temperature at the finishing mill input side from the estimated value of the tip temperature, the estimated value of the tip temperature at the finishing mill input side and the rolling conditions of the finishing mill set in advance, and Estimate the temperature of the material to be rolled at each stand of the finishing mill based on the, based on the estimated material temperature to be rolled, to determine the initial setting value of the rolling material profile control amount of each stand of the finishing mill based on the estimated rolling material temperature How to set up a hot finishing mill.

(3) The method according to the above (1) or (2), wherein the measured value of the surface temperature at the exit side of the heating device is used as the estimated value of the temperature at the tip of the rough rolled material after heating. How to set up a finishing mill.

(4) As the estimated value of the temperature at the tip of the rough-rolled material after heating, the surface temperature measured value at the tip of the rough-rolled material on the inlet side or the outlet side of the heating device, the material and dimensions of the rough-rolled material, and the heating (1) or characterized by using a temperature distribution in the thickness direction of the rough rolled material calculated based on the heating pattern of the apparatus or
(2) The method for setting up a hot finishing mill as described in the item (2).

(5) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between the rough rolling mill and the finish rolling mill, the method comprising: Assuming, the estimated material temperature at each stand of the finishing mill based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, each of the finishing mills based on the rolling material temperature Determine the initial setting value of the rolling position and the roll rotation speed of the stand, and calculate the forward end temperature of the entrance side of the finishing rolling mill from the assumed value of the tip temperature of the rough rolling material on the entrance side of the finishing rolling machine, A hot finish rolling mill characterized by setting a heating pattern of a heating device based on a measured value of a tip surface temperature of a rough rolled material on a heating device entrance side so as to obtain a backward calculated value of the tip temperature. Setup method.

(6) A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between the rough rolling mill and the finish rolling mill, comprising: Assuming, the material temperature at each stand of the finishing mill is estimated based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, and each stand of the finishing mill is estimated based on the material temperature. Determine the initial setting value of the rolling position and the roll rotation speed of the rolling mill, and calculate the forward end temperature of the entrance side of the finishing rolling mill from the assumed value of the leading end temperature of the rough rolling material on the entrance side of the finishing rolling mill. Setting up a heating pattern of the heating device based on the measured value of the surface temperature of the tip portion of the rough rolled material on the inlet side of the heating device so that a backward calculated value of the tip temperature can be obtained; Method.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 4 is an apparatus configuration diagram for explaining a method for setting up a hot finishing mill according to the present invention.

A method of setting up by measuring the surface temperature of the rough rolled material on the exit side of the heating device will be described with reference to the device configuration diagram of FIG. 1 are denoted by the same reference numerals. The rough rolled material is roughly rolled by the rough rolling mill 1, and then
After the rough rolled material 8 is heated by the heating device 20, the finish rolled by the finish rolling mill 2 including a plurality of stands arranged in tandem, and the rough rolled material 8 is measured by the thermometer 21 provided on the exit side of the heating device 20. Based on the detected surface temperature and the rolling conditions set in advance by the rolling condition setting device 10, the set-up device 31 of the finishing mill sets the rolling position of each stand and the initial roll rotation speed. Determine the set value, the rolling position setting device 12,
The output is output to the roll rotation number setting device 13. Furthermore, if the product profile such as crown or edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the initial setting value of the material to be rolled profile control amount is determined,
It is output to the rolled material profile control amount setting device 14.
Based on these results, the roll-down position by the roll-down device 4 of each stand, the roll rotation speed by the roll drive motor 5,
A rolled material profile control amount is set by the rolled material profile control actuator 6.

The operation of the setup device 31 of the finishing mill according to the present invention will be described.

The temperature detected by the heating device outlet thermometer 21 provided on the outlet side of the heating device 20 is used as an initial value for calculating the temperature of the rolled material in the finishing mill. That is,

[0044]

(Equation 8) t ₀ : time when the leading end of the rough-rolled material passed through the heating device outlet thermometer 21, T _b0 : measured value of the surface temperature of the rough-rolled material, ΔT ': surface temperature in the thickness direction of the rough-rolled material and the central part The temperature difference, Here, considering that the surface temperature after heating may be higher than the center as shown in FIG.
A constant value stored in advance or a different parameter is used for each material / dimension of the rough rolled material. For example, ΔT ′ = − 60 ° C. in the heating device having the characteristics shown in FIG.

The temperature of the rolled material after the heating device outlet thermometer 21 is obtained by solving the above-mentioned heat conduction equation (2) under the boundary condition (3) on the rough rolled material surface (thickness direction position x _s ). Ask by.

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed and water usage of the descaler 7 which are preset by the rolling condition setting device 10. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, the leading end of the rolled material is the ith of the finishing mill.
From the temperature T (t _i , x) of the rolled material at the time t _i estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature T _i of the rolled material at each stand is calculated. Calculated and based on this formula (4)
, Calculate the deformation resistance of each stand.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated according to the above-mentioned equations (5), (6) and (7).

Next, based on the determined rolling load and advance rate of each stand, the roll-down position and roll rotation speed of each stand are determined according to the equations (8) and (9).

The operation of the setup device 31 of the finishing mill according to the method of setting up the profile control amount of the finishing mill according to the present invention is performed as follows.

When specifications relating to the product profile of the material to be rolled, such as crown and edge drop, and the shape of the finishing mill are determined, the above-described method of determining the rolling position of each stand and the roll rotation speed is used. From the calculated rolling load of each stand, for example, a rolled material profile control amount is determined according to the known document 1.

Next, in the present invention, the operation of the setup device 31 when setting up the finishing mill based on the temperature distribution in the thickness direction of the leading end of the rough rolled material will be described. The device configuration diagram in this case is the same as FIG.

The temperature distribution of the rolled material is estimated based on the following method. As one form of the heating device, when an induction heating device is used, it is known that the amount of heat given to the rolled material from the induction heating device decreases exponentially from the surface in the thickness direction toward the center. I have. That is, at each time t, the amount of heat Q _b (t, x) given from the heating device to the position of the thickness direction position x of the rolled material is estimated based on a heating pattern that is a time transition such as power consumption of the heating device, The temperature change of the rolled material inside the heating device is calculated using the following equation.

[0054]

(Equation 9) Q _b (t, x): the time t, the amount of heat given from the heating device with respect to the thickness direction of the position x of the rough rolled material, q '(t): Unit at time t time, the heat radiation amount per unit volume.

As a result, the surface temperature T (t _b0 , x _s ) of the rolled material and the temperature T (t _b0 , x _c ) of the rolled material at the time t _b0 at which the leading end of the rolled material is estimated to reach the heating device exit side. ) Respectively. Based on this calculation result, the heating device outlet thermometer 21
The difference between the surface temperature T _b0 detected in step (1) and the temperature at the center of the rolled material is estimated. That is, in the formula (10),

[0056]

(Equation 10) Is used as an initial value for calculating the temperature of the rolled material in the finishing mill.

The temperature of the rolled material after the heating device outlet thermometer 21 is obtained by solving the above-mentioned heat conduction equation (2) under the boundary condition (3).

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed preset by the rolling condition setting device 10 and the amount of water used by the descaler 7. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, from the temperature T (t _i , x) of the rolled material at the time t _i at which the leading end of the rolled material reaches the i-th stand of the finishing mill, for example, the temperature distribution in the thickness direction is averaged. By calculating the average temperature T _i of the rolled material at each stand, the above described (4)
Calculate the deformation resistance of each stand according to the formula.

After that, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated in accordance with the above equations (5) to (7).

Finally, the rolling position and the roll rotation speed of each stand are determined according to (8) and (9) based on the rolling load and the advance rate of each stand determined.

On the other hand, when the product profile such as the crown and edge drop of the material to be rolled and the specifications regarding the shape of the finishing mill are determined, the rolling load of each stand obtained by the setup calculation of the finishing mill described above is determined. Then, the rolled material profile control amount is determined according to the above-mentioned known document 1.

FIG. 5 is an apparatus configuration diagram for explaining a method of setting up a hot finishing mill having a thermometer on the inlet side of the heating apparatus according to the present invention. 4, the same elements as those in FIG. 4 are denoted by the same reference numerals. In the figure, a thermometer is installed on the input side of the heating device 20.

The rough rolled material 8 is roughly rolled by the rough rolling mill 1, then heated by the heating device 20, and then subjected to finish rolling by the finishing rolling mill 2 comprising a plurality of stands arranged in tandem. The surface temperature of the leading end of the rough rolled material 8 is detected by a heating device inlet-side thermometer 22 provided on the inlet side. This temperature T _bi is used as an initial value for calculating the temperature of the rolled material in the heating device 20 and the finishing mill 2. That is,

[0065]

[Equation 11] T (t, x): time t, temperature of rough-rolled material at position x in the thickness direction, t ₀ : time when the leading end of the rough-rolled material passes through the thermometer on the inlet side of the heating device, T _s : surface of the rough-rolled material temperature measurements x _s: coordinate corresponding to the thickness direction of the surface of the rough rolled material, x _c: coordinate corresponding to the thickness direction of the center of the rough rolled material, [Delta] T _b: the thickness direction of the surface of the rough rolled material The temperature difference at the center is

Here, ΔT _b is a temperature change in the rough rolling mill 1 from the temperature at the time of extracting the heating furnace (not shown) installed on the inlet side of the rough rolling mill 1 and the temperature change from the rough rolling mill 1 to the heating device inlet side. The calculation is performed in consideration of a temperature change due to heat radiation up to the thermometer 22, or an empirical constant value is used for the determination. In any case, it is clear that the surface of the rolled material is lower in temperature than the central part on the inlet side of the heating device due to cooling and heat radiation due to contact between the rough rolled material and the rolling rolls of the rough rolling mill. That is, ΔT _b ≧ 0.

Using the rolled material temperature given by equation (14) as an initial value, the temperature change in the heating device is calculated according to the above formulas (11) and (12).
And the temperature change in the finishing mill is calculated according to (2) and (3).

Here, the heat input amounts Q (t) and Q _b (t,
x), the heat release amounts q (t) and q ′ (t) from the rolled material are heating patterns and threading speeds, descalers which are time transitions such as power consumption of the heating device preset by the rolling condition setting device 10. The value at time t when the leading end of the rolled material passes is used based on the amount of water used in 7, the target thickness of the rolled material at each stand, and the like.

Next, the leading end of the rolled material is placed on the i-th finishing mill.
From the temperature T (t _i , x) of the rolled material at the time t _i estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature T _i of the rolled material at each stand is calculated. Then, based on this, the above-mentioned equation (4)
, Calculate the deformation resistance of each stand.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio at each stand are calculated according to (5) to (7).

Thereafter, based on the rolling load and the advance rate of each stand obtained, the following (8) and (9)
Determine the rolling position and roll rotation speed of each stand.

On the other hand, when the product profile such as crown and edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the rolling load of each stand obtained by the setup calculation of the finishing mill described above is determined. Then, the rolled material profile control amount is determined according to the above-mentioned known document 1.

In any of the set-up methods of the present invention described above, after measuring the surface temperature of the rough rolled material on the exit side of the heating device, the setup calculation is started or the rough rolling of the rough rolled material on the entrance side of the heating device is started. After measuring the surface temperature of the material, the heat transfer calculation in the heating device is started to set up the rolling position and roll rotation speed of the finishing mill or the controlled amount of the material to be rolled.

The setup calculation requires a considerable amount of calculation time, and may require a large amount of calculation when calculating the temperature change of the rough rolled material by the heating device. If the distance to is short and the threading speed of the rolled material is fast, after detecting the rough rolled material surface temperature,
Sometimes setup is not in time.

As a countermeasure, the present invention provides a setup method for preferentially determining the setup of the finishing mill and adjusting the heating pattern of the heating device.

FIG. 6 is an apparatus configuration diagram for explaining a method of setting up a hot finishing mill by feed-forwarding a heating pattern of a heating apparatus according to the present invention.

In the figure, in order to secure the rolled material temperature in the finish rolling mill due to material property restrictions and the like, the target rolled material temperature on the entrance side of the finish rolling mill is preset by the target temperature setting device 34.

After the rough rolling material 8 is roughly rolled by the rough rolling mill 1 and heated by the heating device 20, when the finish rolling is performed by the finishing rolling mill 2 comprising a plurality of stands arranged in tandem, the entrance side of the heating device 20 Thermometer 22 provided in
Based on the surface temperature of the leading end of the rough rolled material 8 detected in
By feeding forward the heating pattern to the heating device 20, the temperature of the material to be rolled on the entrance side of the finishing mill is controlled to a target temperature given in advance by the target temperature setting device 34, and the material to be rolled on the entrance side of the finishing mill is controlled. Based on the target material temperature and the rolling conditions set in advance by the rolling condition setting device 10, the set-up device 31 of the finishing mill according to the present invention determines the initial setting values of the rolling position and roll rotation speed of each stand, Output to the position setting device 12 and the roll rotation speed setting device 13.

On the other hand, when the product profile such as crown and edge drop of the material to be rolled and the specification regarding the shape of the finishing mill are determined, the initial setting value of the material profile control amount is determined and the material to be rolled is determined. Output to the profile control amount setting device 14. On the basis of these results, the roll-down position, roll drive motor 5
The roll rotation speed and the rolled material profile control amount are set by the rolled material profile control actuator 6.

The control operation of the setup device 31 is as follows. With the temperature of the rolled material in the finishing mill as the initial value of the target temperature on the finishing rolling mill side, the above-mentioned heat conduction equation (2) is used to calculate the boundary condition (3) on the surface of the rolling material (thickness position x _s ). Find by solving under

Here, the heat input amount Q (t) to the rolled material and the heat release amount q (t) from the rolled material are determined by the passing speed preset by the rolling condition setting device 10 and the amount of water used by the descaler 7. The value at time t when the leading end of the rolled material passes is used based on the target thickness of the rolled material at the stand and the like.

Next, the leading end of the rolled material is placed on the i-th finishing mill.
From the temperature T (t _i , x) of the rolled material at the time t _i estimated to reach the stand, for example, by averaging the temperature distribution in the thickness direction, the average temperature T _i of the rolled material at each stand is calculated. Calculated and based on this formula (4)
, Calculate the deformation resistance of each stand.

Next, based on the determined deformation resistance of each stand, the rolling load and the advance ratio in each stand are calculated according to the above-mentioned equations (5) to (7).

Thereafter, based on the determined rolling load and advance rate of each stand, the rolling position and roll rotation speed of each stand are determined in accordance with the equations (8) and (9).

On the other hand, when the product profile such as the crown and edge drop of the material to be rolled and the specifications relating to the shape of the finishing mill are determined, the finishing mill calculated by the above-mentioned finishing mill set-up device is calculated. From the rolling load of each stand, the rolled material profile control amount is determined according to the known document 1.

[0086]

EXAMPLE A comparative test result by simulation is shown in a hot rolling facility in which a thermometer for detecting the temperature of a rolled material is installed on the outlet side of a heating device and a work roll bender is provided as an actuator for controlling a profile of a material to be rolled. .

Table 1 shows estimated values of the temperature of the rolled material at each stand of the finishing mill as test results when the method of using the surface temperature on the outlet side of the heating device according to the present invention for the setup calculation is applied. The surface temperature on the exit side of the heating device is an actually measured value). Here, F1 to F7 indicate the first to seventh stands of the finishing mill.

[0088]

[Table 1] Table 2 shows the estimated values of the temperature of the rolled material at each stand of the finishing mill as test results when a conventional method using the temperature measurement value at the entrance of the finishing mill for the setup calculation is applied (however, the heating device output Side surface temperature measured value).

[0089]

[Table 2] If the method according to the present invention is applied, on the exit side of the heating device, the rolled material temperature in the finishing mill is calculated by accurately estimating that the temperature of the rolled material central portion is lower than the surface, When the conventional method is applied, since a heating device is not assumed, the temperature of the rolled material in the finishing mill is calculated by erroneously estimating that the temperature at the center of the rolled material is higher than the surface.

Tables 3 and 4 show the differences between the initial setting values of the rolling position and the roll rotation speed determined by the two methods based on the temperature calculation results.

[0091]

[Table 3]

[Table 4] Table 5 shows the deviation of the product thickness (thickness on the exit side of the final stand F7) at the tip when rolling was performed by setting the rolling position and the roll rotation speed to the initial set values in Tables 3 and 4. However, it is understood that deterioration of the dimensional accuracy of the product can be prevented by implementing the present invention.

[0092]

[Table 5] Next, using the surface temperature of the heating device exit side according to the present invention, as a test result when applying a method of setting up the profile control amount of the material to be rolled, the initial setting value of the work roll bender in each stand of the finishing mill Are shown in Table 6.

[0093]

[Table 6] Set the work roll vendor to the initial settings in Table 6,
Table 7 shows the product crown deviation at the leading end when the rolling is performed. It can be seen that the dimensional accuracy of the product can be prevented from deteriorating by implementing the present invention.

[0094]

[Table 7]

According to the present invention, the initial setting of the rolling position and the roll rotation speed of the finishing mill or the control amount of the material to be rolled can be performed with high accuracy in a hot strip mill for a metal strip having a heating device. It is possible to guarantee the dimensional quality of the rolled material tip.

[Brief description of the drawings]

FIG. 1 is an apparatus configuration diagram for explaining a setup method of a finishing mill in a general hot rolling facility.

FIG. 2 is a graph showing an example of a temperature distribution in a thickness direction of a material to be rolled.

FIG. 3 is a schematic graph showing an example of a change in temperature of a rolled material before and after passing through a heating device.

FIG. 4 is an apparatus configuration diagram for describing a setup method of a hot finishing mill according to the present invention.

FIG. 5 is an apparatus configuration diagram for explaining a setup method of a hot finishing mill having a thermometer on an inlet side of a heating apparatus according to the present invention.

FIG. 6 is an apparatus configuration diagram for explaining a setup method of a hot finishing mill by feed-forwarding a heating pattern of a heating apparatus according to the present invention.

[Description of Signs] 1: Rough rolling mill 2: Finishing rolling mill 3: Finishing rolling mill inlet side thermometer 4: Rolling-down device 5: Roll drive motor 6: Rolled material profile control actuator 7: Descaler 8: Rough rolling material 10: Rolling condition setting device 11: Setup device 12: Rolling position setting device 13: Roll rotation speed setting device 14: Rolled material profile control amount setting device 20: Heating device 21: Heating device outlet thermometer 22: Heating device input Side thermometer 31: Setup device 34: Target temperature setting device

Claims (6)

[Claims] 1. A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, comprising: Estimate the tip temperature on the entrance side of the finishing mill from the estimated value of the tip temperature, and the estimated value of the tip temperature on the entrance side of the finishing mill and the preset rolling conditions of the finishing mill. Estimating the temperature of the material to be rolled at each stand of the finishing mill based on the estimated rolling material temperature, and determining the initial setting value of the rolling position and the roll rotation speed of each stand of the finishing mill based on the estimated material temperature. How to set up a hot finishing mill. 2. A method for setting up a hot finishing rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, comprising: Estimate the tip temperature on the entrance side of the finishing mill from the estimated value of the tip temperature, and the estimated value of the tip temperature on the entrance side of the finishing mill and the preset rolling conditions of the finishing mill. Estimating the temperature of the material to be rolled at each stand of the finishing mill based on the estimated rolling material temperature, and determining an initial set value of the rolling material profile control amount of each stand of the finishing mill based on the estimated material temperature. How to set up a hot finishing mill. 3. The hot finish rolling mill according to claim 1, wherein the measured value of the surface temperature at the outlet side of the heating device is used as the estimated value of the temperature at the tip of the rough rolled material after heating. Setup method. 4. An estimated value of the temperature of the leading end of the rough-rolled material after heating, the measured surface temperature of the leading end of the rough-rolled material on the inlet side or the outlet side of the heating device, the material and dimensions of the rough-rolled material, and the heating device The hot finish rolling mill set-up method according to claim 1 or 2, wherein a temperature distribution in a thickness direction of the rough rolled material calculated based on the heating pattern is used. 5. A method for setting up a hot finish rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, comprising: Assuming, the material temperature at each stand of the finishing mill is estimated based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, and each stand of the finishing mill is estimated based on the material temperature. Determine the initial setting value of the rolling position and the roll rotation speed of the rolling mill, and calculate the forward end temperature of the entrance side of the finishing rolling mill from the assumed value of the leading end temperature of the rough rolling material on the entrance side of the finishing rolling mill. Setting up a heating pattern of the heating device based on the measured value of the surface temperature of the tip portion of the rough rolled material on the inlet side of the heating device so that a backward calculated value of the tip temperature can be obtained; Method. 6. A method for setting up a hot finishing rolling mill in a metal strip rolling mill having a heating device between a rough rolling mill and a finishing rolling mill, comprising: Assuming, estimating the material temperature at each stand of the finishing mill based on the assumed value of the tip temperature and the rolling conditions of the finishing mill, and estimating the material temperature at each stand of the finishing mill based on the material temperature. Determine the initial setting value of the rolling position and the roll rotation speed, and calculate the tip temperature of the entrance side of the finishing rolling mill backward from the assumed value of the tip temperature of the rough rolled material on the entrance side of the finishing rolling mill, and calculate the Setting up a heating pattern of a heating device based on a measured value of a surface temperature of a leading end portion of a rough rolled material on an inlet side of the heating device so as to obtain a backward calculated value of a temperature of the heating device. .