JPS6167515A - Control method of plate thickness in width direction of rolling material - Google Patents

Abstract

PURPOSE:To obtain a uniform plate thickness in longitudinal direction and width direction by providing independently a bending device at work side and driving side and by performing an automatic plate thickness control and bender control successively at each stand with performing the load distribution control for each stand of the operation quantity. CONSTITUTION:The weight co-efficient of the bender operation quantity of a work side and driving side is determined with measuring the thickness of a rolling material 10 by the thickness gage 12 of the outlet side of the final stand 20 of a continuous rolling mill and a scanning type thickness gage 14 and with calculating a wedge rate and the plate thickness distribution curves in width direction by an arithmetic unit 28. The information of a rolling constant is fed to a subordinate computer 30 from a host computer 38 and the subordinate computer 30 takes in the signal transmitted from a reaction force gage 22 and pressure detectors 24, 26. The automatic plate thickness control and bender control are successively performed then with commanding to automatic plate thickness control system 32 and bending control system 34, 36 of the work side and driving side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the thickness in the width direction of a rolled material such as a steel strip rolled by a rolling mill with AGC.

(Prior Art) The rolled material (hereinafter simply referred to as "material") extracted from a walking beam type heating furnace is transferred to the rolling material (hereinafter simply referred to as "material") in the 2X5 furnace (on the surface of the material that hits the general delivery skid).

A mark is generated, the temperature of the material decreases at the mark portion, and the temperature distribution of the material becomes non-uniform. As this material with non-uniform temperature distribution is continuously rolled, the skid marks become enlarged and become non-uniformly distributed in the width direction. As a result, temperature deviation occurs in the width direction of the material, and the deformation resistance of the material differs in the width direction, resulting in uneven thickness of the product in the width direction.

In addition, recent energy-saving rolling methods have increased the material thickness and lowered the heating furnace extraction temperature, but according to the industrial law, the ripening temperature at the edge of the material has increased to 11, and the temperature in the width direction has also increased. The deviation tends to increase, and the non-uniformity of the thickness of the product in the width direction is promoted. Recent customer needs are demanding not only product quality but also products that are uniform in the width direction, and there is a great need to eliminate the above-mentioned problems.

Gauge meter-based AGC (automatic plate thickness control) is widely adopted in continuous rolling mills, and has been highly effective in increasing the degree of control of plate thickness. On the other hand, although roll bending equipment has been adopted, the bending pressure is only pre-centered to a set value according to the pass schedule before rolling, and the bending pressure within a single piece of material is rarely changed. However, recently, the problem of the shape (flatness) of seven-dimensional materials has been widely discussed, and various control methods and devices for this purpose have been developed. The main method is to use a roll hending device to change the hending pressure within a single material according to the thickness deviation of the material in the width direction, so that the thickness is uniform in the width direction over the entire length. This is a method that attempts to achieve this.

However, there is a problem in that plate thickness control and shape control interfere with each other. In other words, when the shape control system changes the roll hedding force by controlling the shape, the roll downward direction (rolling reaction force) changes, which causes the AGC system to operate, and the AGC system also operates to close the roll gap. If you change it, the rolling reaction force will change, and this will change the shape (crown), so the shape control system will be improved. It has been considered to eliminate such mutual interference so that each device can operate independently, and Japanese Patent Laid-Open No. 58-138508 is an example of this. This means that if the thickness variation on the exit side is corrected to Δh, the variation in the crown on the exit side to ΔCr, the reduction operation amount to ΔS, and the heading is corrected (E is a unit matrix), the operation amounts ΔS and Δr will no longer interfere with each other. It is something. However, in this method, the hending pressure operation amount (Δr) is a single loop (work side and drive side are integrated), and if the wedge ratio of the material differs at the entrance side of the rolling mill, Since it is necessary to change the amount of hending pressure operation on the work side and drive side of the rolling mill, it is impossible to control the thickness to be uniform in the width direction with this method.

Anti-crown feedback control is performed by detecting the crown and operating the operating end, in this example a roll bender, so that the difference from the target crown becomes O. The crown indicates the center height of the board, and the thickness distribution assumes left-right symmetry, so the crown measurement can be performed by measuring the thickness at the temporary center and at one edge of the board. However, since a wedge exhibits left-right asymmetry in thickness distribution, it is necessary to measure the thickness at the left and right ends of the sheet, and in order to control the shape by taking wedges into account, 1 inverse thickness measurement force < (iiT + hardness) This means that it is also necessary.

The present invention aims to improve these points and make it possible to control the shape including the wedge without interfering with AGC and without using a large number of plate thickness gauges.

(Structure and operation of the invention) The present invention performs automatic plate thickness control and installs a roll bender at the work site and drive side (ii). In , the plate thickness Δ1 is fixedly placed on the center line of the plate thickness il and +AI4 which moves in the width direction at the starting end of the material and then rests at one edge of the material (O starting, '7i!,'
Measure the thickness distribution in the width direction and the crown distribution in the length direction of the section, and add these measured values to the one-piece production amount of each hender at the work site and drive site and the mulberry production amount of the other bender I for the operation amount. Weight (calculate the number of threads, then add correction to remove the mutual interference between automatic T & I control and Henter control, input the corrected operation amount into the work side, drive side, etc., and calculate the width of the material. This is characterized in that the directional plate thickness distribution is uniformly controlled over the longitudinal direction≦mm length.First, this will be explained with reference to embodiments.

First, the method for measuring the plate shape will be explained. This can be done simply by arranging a large number of plate thickness gauges across the entire width in the opposite width direction and measuring the thickness directly under each plate thickness gauge.If this is done continuously during plate rolling, Capable of measuring the crown and wedge of the entire length of the board. The plate meanderes during rolling, and in order to correct this, the plate thickness gauge group can be reciprocated in accordance with the meandering. However, this method requires high equipment costs. In this regard, the method developed by the present inventor and filed separately requires only the use of two plate thickness gauges.
It is extremely effective.

To explain this shape measurement method with Figures 2 and 3, 1
0 is the rolled material and the arrow is its direction of movement. 12
1 is a plate thickness gauge fixedly attached so as to aim at the center line 10a of the material 10, and 14 is a scanning type plate thickness gauge that is movable in the width direction of the plate. As the material 10 moves, the plate thickness gauge 12 measures the material 1.
The thickness of the plate at the center line of 0 is sampled and measured (the black dots are the sampling points), and the plate thickness meter 14 first moves across the entire width and then is fixed at a slightly returned position, so the plate thickness on the lines 14a and 14b is sampled and measured. do. Line 1・1. ] By measuring the thickness of the material above, the crown and wedge at the tip of the material are measured, and by measuring the thickness of the material on the cotton 14b, the crown at each point in the length direction of the material: l'410 is determined (f, 11). (Also use the output of 12).

That is, at the tip of the material 10, the crown and wedge are determined by one rule for one thickness at each point in the width direction, and then the thickness at the center of the +71 material and one end of the material (at a point 25 mm from the edge, -
Crown i31. The crown is determined over the length of the plate by measuring the plate thickness at the fixed point.

If the material is meandering, the plate thickness measurement will be incorrectly aligned with the center line of the material.
0a and one end portion 14b. Crown and wedge measurements at the leading edge of the material address this meandering.

Assuming that the shape of the thickness distribution in the width direction at the edge of the material Hμ, the shape of the function f (X) in Figure 3, does not change throughout the entire length of the material, and that there is no change in the thickness, meandering is simply a parallel movement. It is considered that the material surface 10b is 1 as shown in FIG.
This means that it has moved to the position 0b' or vice versa. Since the position of the plate thickness gauge 14 does not change, if the plate meanderes, the measurement point Pl becomes P3, which is no longer the correct measurement point 25 degrees from the edge. The correct measurement point after meandering is P2,
Therefore, the plate thickness gage 14 can be moved to the point P2, but this requires the servo JatR and is troublesome. Therefore, we take a method of correcting it by calculation. i.e. the first line 14
The function f (xi
Therefore, the measured value of the plate thickness meter 14, where xo is the width direction position of the measuring point P1, is f(xo), and the measured value after meandering by b is f(xo b). In reality, since there is a change in the plate thickness, the output of the plate thickness meter 14 includes the actual plate thickness change ±Δ and the above change f(xo) −f(xo b) due to meandering, and the latter is the output of the plate thickness meter. By subtracting it from , you can find the former, that is, the actual thickness change.

If the meandering occurs, the thickness gauge 12 will no longer be able to accurately measure the thickness at the center of the material, but the change in film thickness per stroke near the center line is not large (and the amount of meandering is generally a minute value such as 5 nm). Therefore, this modification may be omitted.Furthermore, the wedge may also be left unchanged over its entire length.

[The wedge rate hWD of the material is defined by the following formula.

Here, hw and hD are the plate thicknesses at point α■ of the work side and drive side part of the work side obtained by scanning in the width direction of the plate thickness 14, and α is also 25. It is m.

hwD = hw/hD -1+1 The amount of hending pressure operation on the work side and drive side is Δb1
．． 2 Assuming ΔbD, when the material has a wedge, the hending pressure I = yield is as follows: Since the material is rolled with symmetry in the width direction, Δbw = w・ΔbD, Δ
bD-=Δ1) D=-(2). Here, W is a weighting factor (7) that corresponds to hwd for the bender operation H of the work site, 1" foot 4 node. hv
Since /D is obtained by the width direction scan, it is possible to continuously control the bending forces of the work side and the trifle site to values suitable for each.

Figure 4 shows the temperature profile in the longitudinal direction of the material;
(b) shows the temperature profile at the width end. From these (a) and (b), a temperature deviation of about 50°C in the width direction is recognized. Furthermore, the amplitude of (a) is about twice that of (b), and it is clear from this that the skid marks of the material are large at the center of the width and become smaller toward the ends.

FIG. 5 shows the thickness profile of the material in the longitudinal direction of tbl when the AGC is "off" (a) and when it is "on" for the same size material. In the same figure, (a) is the plate thickness variation at the center of the width, (b) is the plate thickness variation at the width end, and (c) is (a) - (b), that is, the thickness deviation in the width direction of the material. shows the amount of variation (crown amount). A, G
When C is turned off (fa), as shown in Figure 4, the amount of temperature variation at the edges is smaller than that at the center, so the plate thickness variation at the edges is smaller than that at the center. It has become considerably smaller and is within the control limits. However, since the temperature variation opening in the longitudinal direction is large at the center of the width, the amount of plate thickness variation is also large, about twice as much as at the ends. AGC is effective in reducing this amount of variation. Figure 2) shows the case when AGC is turned on, and the variation in plate thickness in the medium heat area is clearly reduced.
The control effect appears in spring.

However, on the other hand, when AGC is turned off (it increases by about twice compared to a+), the amount of plate thickness variation at the edge is approximately twice that of AGC.This indicates that AGC interferes with the plate thickness at the edge. It is clear that this is the case.

The control target is the plate thickness variation ΔhC on the exit side at the central part, the plate thickness variation ΔhD on the exit side at the worksite side θj;
Lowering position operation amount ΔS, moving to work side, turning original amount Δto〃, drive site heading operation MΔbD
and corrected so that there is no mutual interference, the control becomes f
(ΔS, ΔbD) and g(ΔS, Δb horn) are non-interference terms with respect to the respective hending operation ports of the work site and drive site. In order to make the board thickness uniform in the width direction, Δhc - Δhw - Δhc - ΔhDZO (4
), and from equation (4), Δhw-ΔhD=Δhc...
(5) If Δhc is set to O by AGC, (31,
(Formula 51 %Formula %) Using the relationship Δbw=W・ΔbD in equation (2) above, g(ΔS, Δbw) −g (ΔS, W−ΔbD)
・・・・・・(7) Therefore, from equation (6), Δb in equation (8) becomes Δbw=-w using equation (2).
-g(ΔS, W-ΔbD)...(9) These (8), (From type 91, when AGC is turned on, the work side and drive side hending operation ports are It is given by the formula 001.

FIG. 1 shows an embodiment of the present invention. A thickness gauge 12 and a thickness gauge 12 placed on the exit side of the final stand 20 in the shallow end of the continuous rolling mill +7 (10) scan the entire width at least once to measure the thickness profile in the width direction. The thickness of the plate is measured using a scan type thickness gauge 14 that measures the thickness of the plate at a point a certain distance away from one of the rear ends toward the center,
t'A calculation device n 81: Calculates the wedge ratio and width direction plate thickness distribution curve of the rolling material, and determines the weighting coefficient W of the nodder operation amount on the work side and drive side.Rolling constant (mill Characteristic.

The information on the material properties, etc.) is sent from the upper computer 38 to the lower 61 computer (DDC computer) 30, and the information on the lower-order meter W (Cut 30 is also the reaction force meter 22. Continuously captures the signals from the pressure detectors 24 and 26, and outputs the command signal to prevent mutual interference between the AGC and bender control. Function g (Δ
S , A b D) (!: m mi (15W to!:
=L The bending operation order Δb is given by the equation.

ΔbD is defined as work side (WS) and drive site (
DS) to the steering control system 34.36, and the AGC
By continuously controlling the bender and bending, it is possible to produce a plate with uniform thickness in the length and width directions of the material.

In column 7), we focused on the final stage stand and explained the control of this stand, but in reality, the hending device is placed independently at the work site and drive site in the last few stands or all the stands, and each of the operation amount is By controlling the load distribution to the stands, AGC and bender control are performed continuously at each stand, thereby producing a uniform plate thickness in the width direction of the material.

[Effects of the Invention] As explained above, according to the present invention, uniform plate thickness can be achieved in the length direction and width direction of the rolled material, and only two plate thickness gauges are required for this control. It's extremely beneficial.

[Brief explanation of the drawing]

Figure 1 does not show an embodiment of the present invention; Figures 2 and 3 illustrate the plate shape; Figures 5 and 1 are graphs showing the temperature distribution in the length direction; The figure is a graph showing plate thickness changes and crown changes in the opposite longitudinal direction. In the drawing, 32 is an automatic plate thickness control (AGC) device, 20 is a rolling mill, 10 is a rolling material, Yo” Noke side, drive side each heading system 1llll system, 1
2.14 is a plate thickness gauge. Applicant Nippon Steel Corporation Representative Patent Attorney Ao (Minoru U)

Claims (1)

[Claims] In a method for controlling the thickness in the width direction of a material rolled in a continuous rolling mill that performs automatic thickness control and is equipped with a roll bender on the work side and drive side, the thickness is moved in the width direction at the starting end of the material, and then one end edge of the material is rolled. The thickness distribution in the width direction and the crown distribution in the length direction at the starting end of the material are measured using a plate thickness gauge that is stationary on the part and a plate thickness gauge that is fixedly placed on the center line of the material. Drive side: Find the manipulated variable of each bender and the weighting coefficient to be added to the manipulated variable of the other bender, and then add correction to remove the mutual interference between automatic plate thickness control and bender control, and apply the corrected manipulated variable to the workpiece. A method for controlling the thickness in the width direction of a rolled material, characterized by inputting information to each bender on the side and drive side to uniformly control the thickness distribution in the width direction of the material over the entire length in the longitudinal direction.