JPH0225210A - Wedge control method in hot rolling - Google Patents

Abstract

PURPOSE:To perform a wedge control with high accuracy at the time of hot rolling by comparing a wedge calculated value in the longitudinal direction of a rolling material and an actual result value in the past, and deriving an opening difference at the time of zero-calibrating a roller opening sensor, and using it for a wedge calculation of the rolling material of the next pass. CONSTITUTION:A wedge which is generated at the time of bringing a rolling material 1 to hot rolling by a rolling mill 2 is controlled. First of all, a wedge calculated value is derived by measuring a difference load of the previous pass, a roller opening, etc., by a roller opening meter 5, etc., at each position in the longitudinal direction of the rolling material 1. Subsequently, a measured value is measured by a wedge sensor 11. By comparing this measured value and the wedge calculated value, an opening difference at the time of zero- calibrating a roller opening sensor is derived. By using a value of this opening difference, a wedge of the rolling material of the next pass is controlled by a controller 8. In such a way, a wedge control can be performed with high accuracy at the time of hot rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wedge control method in hot rolling.

<Prior Art> Normally, when a steel plate is manufactured using a hot rolling mill, camber and wedges often occur in the rolled material, deteriorating its shape.

Camber means bending in the longitudinal direction of a steel plate, and the degree of curvature is indicated by the curvature k, as shown in Figure 3 (al). Wedge refers to the degree of thickness deviation in the width direction of the rolled material 1. - As shown in Figure 3 (bJ), for boat fishing, the plate thickness on the reassembled side of the rolling rolls of the rolling mill (hereinafter simply referred to as the reassembled side) and the drive side of the rolling mill (hereinafter referred to as the reassembled side). , simply referred to as the drive side), is expressed as the difference Δh.

Now, as shown in Fig. 4 (a), the entrance camber curvature of the rolled material l on the entry side of a certain rolling mill is + the entrance wedge Δt++ (= hc + h+++), and Fig. 4 (■) As shown, if the exit side wedge of the rolled material l on the exit side of the rolling mill is Δh, (=h, .-h, .),
The exit camber at that time can be expressed as (1) 2 below.

k, = f (ki, Δht, Δh,, hi.

h,) ・・・・−・・−・〜・・・・
-・-・(1) Here, hl; Entry side thickness of the rolled material 1 h o i Output side thickness of the rolled material 1 Therefore, the entry side and exit side wedge Δh+.

Accurately measure Δh0 (and measure the exit wedge Δh
If 0 can be controlled accurately, correction control of the exit camber can be realized.

By the way, it is possible to measure the wedge with high precision by using a wedge sensor that measures the plate thickness on the recombination side and the drive side using a gamma ray thickness meter, for example. However, it is difficult to install such a wedge sensor near a rolling mill in a poor environment, and it is necessary to install it far away from the rolling mill.Therefore, feedback using the measured values of such a wedge sensor is difficult. The wedge control method is generally difficult due to the large dead time.

Therefore, the conventionally considered wedge control method uses rolling data of the rolled material measured directly below the rolling mill and various process data of the rolling mill to control the opening of the rolls on the drive side. Attempts are being made to implement this by doing n.

FIG. 5 is an explanatory diagram schematically showing a conventional wedge control system. As shown in FIG. , the rolling load P and roll opening degree S at that time are measured by rolling load meters 4a, 4b and roll opening degree meters 5a, 5b, respectively.

Further, the meandering amount δ and the plate width W of the rolled material 1 are measured by the meandering amount detector 6. Each board width is measured using a board width meter 7. These measurement signals are all input to the control device 8, and the exit side wedge Δh of the rolled material 1 at the exit side of the rolling mill is determined by the following equation (2).
Calculate 0.

Δh, -g (ΔP, P, ΔS, δ, W)...
-・------・(2) Here, ΔP; Differential load (kgf) -Pc -P.

Pei recombination side rolling load PIl: Rolling load on drive side P; Rolling load (kgf) -Pc 10p.

ΔS: Roll opening difference (m) δ: Meandering! (Kaku) W ; Plate width (Peng) By outputting a control signal based on the exit wedge Δh0 obtained by this equation (2) to the roll reduction devices 3a and 3b, the exit wedge control of the rolled material l is performed. It is.

Note that this equation (2) can be expanded and expressed as the following equation (1).

Δh11 ;al ・ΔP + at ・P +a3
HΔS+am ・δ+a, ・W ・---
---・-(g) Therefore, if we use analysis methods such as the ill element method, which has been significantly developed in recent years, this equation (r) can be expressed as follows:
It is possible to calculate the exit wedge Δh0 with considerable accuracy.

Here, it is difficult to measure the meandering amount δ and the strip width W of the rolled material 1 directly below the rolling mill 2 using the meandering amount detector 6 and the strip width meter 7, but it is difficult to In the device 8, the actual shape of the rolled material in the previous pass in the case of thick plate rolling or in the front stand in the case of tandem rolling such as hot strip is stored in advance as a reference shape, and the meandering amount detector 6 and the plate width meter 7 are used. If the edge position of the rolled material l is measured by installing it at a position away from the rolling mill 2, and the measured value is calibrated using the reference shape, geometrically the meandering amount δ or The plate width W can be determined with considerable accuracy.

Also, a rolling load meter 4a that measures the rolling load P.

4b may use, for example, a load cell or the like, and measures the rolling loads Pc and Po on the recombination side and the drive side, respectively. When the rolling mill 2 has no rolled material l, that is, when there is no load, zero calibration is performed on the recombination side and the drive side. Furthermore, since there is almost no machine difference between these two load cells, Differential load ΔP (-PcPa) and rolling load P (=pc+po) can be measured with high accuracy.

As the roll opening degree sensors 5a and 5b, sensors such as a pulse generator and a magnetic length measuring device are used, for example, and are attached to the recombination side and the drive side, respectively, to determine the roll opening degree Sc,
Measure S. These calibrations are carried out by applying a constant load to the fishing boat as a calibration load after a kiss roll, and performing zero calibration at that point.

<Problems to be Solved by the Invention> By the way, in the above zero calibration, depending on the contact condition of the upper and lower rolls during kiss roll, the respective output values of the roll opening degree sensors 5a and 5b on the recombination side and the drive side may have a certain value. Misalignment occurs. The magnitude of this deviation is large, on the order of several tens of micrometers, and greatly affects the calculation accuracy of the exit side wedge Δh0 obtained by the above-mentioned equation (2).

Now, the deviation that occurs during zero calibration is ΔS.

Then, the actual roll opening difference ΔS used in the above equation (2) can be expressed by the following equation (3).

ΔS−ΔS9 +ΔS0 −・・−・−・−・・
... (3) Here, ΔS1 ; Roll opening difference measurement value In the above equation (3), ΔS0 is an unknown term, so in order to realize the exit side wedge control described above, this ΔS
It is necessary to find 0 with high accuracy, but no suitable means has been found at present.

An object of the present invention is to solve the above problems and provide a highly accurate wedge control method in hot rolling.

<Means for Solving the Problems> The present invention solves the problem of wedges generated in a rolled material during hot rolling of a steel plate by (al) differential load in the previous pass or stand, rolling load, roll opening, and roll opening difference. , amount of meandering.

A process of measuring the plate width at each position in the longitudinal direction of the rolled material to obtain a wedge calculation value, (b) A process of measuring the wedge actual value of the previous pass or previous stand using a wedge sensor, (c) This wedge Compare the actual value and the wedge calculated value,
(d) Calculating the value of the opening difference at the time of zero calibration of the roll opening sensor according to the difference; (d) Using this calculated opening difference value, the wedge of the rolled material in the next pass or the next stand is determined. The above objective is achieved by controlling through the following steps:

<Function> According to the present invention, zero calibration of the roll opening sensor is performed by comparing the wedge 91 calculated value in the longitudinal direction of the rolled material in the previous pass or the previous stand with the actual wedge value measured using the wedge sensor. Since the difference in the opening degree is calculated and reflected in the wedge control of the rolled material in the next bus or the next stand, it is possible to perform highly accurate wedge control.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram schematically showing an embodiment of the method of the present invention. In the drawings, the same members as in the conventional example are given the same reference numerals.

In the figure, the rolling load meter 4 uses a load cell, the roll opening degree meter 5 uses a pulse generator, and the meandering amount detector 6 uses an optical steel plate edge measuring device.

Each signal measured by these measuring instruments and board width gauge 7 is sent to the control device! 8 is input.

11 is a wedge sensor, and a gamma ray thickness gauge is attached to the rolling mill 2.
The rolling mill 2 is installed on the exit side of the rolling mill 2 at a slight distance from the rolling mill 2.

Reference numeral 12 denotes a learning device, which records the actual rolling values at each position in the longitudinal direction of the rolled material 1 rolled in the previous pass or stand in the previous pass or stand from each measuring device input to the control device 8. It has a function of learning the difference in roll opening degree at the time of zero calibration of the roll opening degree meter 5 and outputting it to the control device 8.

Below, the operational procedures for measurement, calculation, and control of the present invention will be explained.

■ In the learning device 12, the actual differential load value ΔP at each position in the longitudinal direction of the rolled material on the previous pass or stand
0. Rolling load actual value P0. Roll opening difference actual value ΔS0.
Meandering amount actual value δ9 and plate width actual value W''' are each measured, and exit side wedge calculated values Δh, c* are determined by the following equation (4) based on the above-mentioned equation (2).

Δ h, ♂ −g (ΔP”, P”, ΔS11,
δ1W1)・・−・−・−・・・・・・・−・・
・・・−・−・・・−・(4) Here, ΔS1 is the actual roll opening difference, and based on the above formula (3), the following (5)
Expressed by the formula.

ΔS″″ −ΔS1+Δs o ” −−−−−−−−
---(s) ■ On the other hand, the output side wedge actual value of the previous pass or the front stand using the wedge sensor 11; Δh, C
is measured at each position in the longitudinal direction of the rolled material.

■ Compare this output side wedge actual value Δh am” with the wedge calculated value Δh@♂ obtained by equation (4), and calculate Δh
@C”−Δh・r−・−・・・・−・−・−・−・
A roll opening difference ΔS01 that satisfies (6) is calculated and output to the control device 8.

The roll opening difference ΔSo" obtained in this way at the time of zero calibration is calculated using a statistical calculation method, since many actual values for boat fishing include statistical errors. If so, it can be determined with high accuracy.

■ Next, in the control device 8, the camber measurement device (
kI
o, and if the entry side wedge Δh is 1 person's side plate thickness hl and the target thickness hea is 1m, then from the above equation (1), the target wedge is calculated using the following equation (7) so that 6" is zero for the exit camber. Find Δh a aim.

0=f(k+, Δh+, Δh a mIm
*h+, h--! −)・・・・・・・・・・・・・
・・・・−・(7) ■ Then, using the roll opening difference ΔS00 at the time of zero calibration input from the learning device 12, the following ( 8) The roll opening degrees S, , SO of the rearranging side and the driving side are determined so as to satisfy the equations (9), and the roll opening degrees of the rearranging side and the driving side are respectively controlled.

Δh, 11shi=-g(ΔP”, P”, ΔS0″δ”, W
”)・−・−・・−・−−−−・−(8) ΔS ”
= S c S s =−−−−−−−−=−
−−−−−−−−・−(9) Here, the roll opening degree difference ΔS at the time of zero calibration. As a learning method, calculate wedge value Δh*c'' of rolled material 1 obtained by equation (4), wedge actual value Δh, 7 difference load ΔP1. Rolling load actual value P1. Roll opening difference ΔS10. Actual meandering amount. Value δ0.Plate width actual value W
0 was averaged, and the obtained roll opening difference ΔS,* at the time of zero calibration was used as an instantaneous value, and the exponential smoothing method of the following formula 01 was applied.

Δ5OI−αΔSo“1st(1−α)Δ3,611−11 0[D Here, Δso′;+Roll opening difference at the time of zero calibration (learning value) Δ3.*14−11 i ( + -1) Difference in roll opening (instantaneous value) at the time of zero calibration α; Coefficient The results are shown in Figure 2.
The actual roll opening difference during zero calibration is approximately loOam
It can be seen that the number of times of exponential smoothing is about 5 and the identification is almost good.

<Effects of the Invention> As described above, according to the present invention, the calculated wedge value in the longitudinal direction of the rolled material in the previous pass or stand is compared with the past wedge actual value, and the zero value of the roll opening sensor is determined. The opening difference during calibration was determined and used to calculate the wedge of the rolled material for the next pass or stand.
It is possible to perform wedge control with high precision.

In addition, in realizing wedge control in hot rolling,
The present invention is essential.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing an embodiment of the method of the present invention, FIG. 2 is a characteristic diagram showing the process of determining the roll opening difference during zero calibration using an exponential smoothing method, and FIG. , (a) is a plan view showing the shape of the rolled material, (b) is a front view, FIG. 4 is a perspective view showing the relationship between the camber of the rolled material and the wedge, and FIG. 5 is a schematic diagram of a conventional example of the wedge control system. FIG. 1...Rolled material. 2...Rolling mill. 3... Roll reduction device. 4...Rolling load meter 5...Roll opening gauge. 6... Meandering amount detector 7... Board width gauge 8... Control device. 11...Wedge sensor 12...Learning bag! .

Claims (1)

[Scope of Claims] A method for controlling a wedge in hot rolling, characterized by controlling a wedge produced in a rolled material during hot rolling of a steel plate by the following steps. (a) A process of measuring the differential load, rolling load, roll opening, roll opening difference, meandering amount, and plate width at each position in the longitudinal direction of the rolled material in the previous pass or stand to obtain wedge calculation values, ( b) Measuring the wedge actual value of the previous pass or previous stand using a wedge sensor; (c) Comparing this wedge actual value with the calculated wedge value and adjusting the roll opening sensor according to the difference. a step of calculating the value of the opening difference at the time of zero calibration; (d) a step of controlling the wedge of the rolled material in the next pass or the next stand using the calculated opening difference value.