JPH07227609A - Plate thickness control method - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the plate thickness accuracy of the leading edge of steel plates in the hot rolling process. [Structure] In a plate thickness control method for a hot continuous rolling mill having a plurality of stands, an intermediate stand plate thickness gauge and a final output plate thickness meter are provided between the stands and on the final stand exit side, respectively, and the intermediate stand plate thickness gauge is used. Estimate the plate thickness deviation due to the final output side plate thickness gauge from the plate thickness deviation due to the measured plate thickness gauge and the gauge meter plate thickness of the stand immediately after the intermediate stand plate gauge, Correct the gap and peripheral speed of 2 or 1 stand. Further, the final exit-side plate thickness is estimated in consideration of the load deviation calculated from the gauge meter plate thickness, and the same correction operation is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate thickness control method for obtaining a desired tip plate thickness in equipment for manufacturing hot rolled steel plates.

[0002]

In the plate thickness control of a hot continuous rolling mill having a plurality of stands, the plate thickness measured by a plate thickness gauge provided on the exit side of the final stand is usually fed back to each stand to control the plate thickness. I do. However, since this is control after the tip of the steel sheet has already left the final stand, it has been pointed out that the thickness of the tip of the steel sheet cannot be controlled and the yield is poor.

Therefore, in order to obtain a desired plate thickness from the tip of the steel plate, a method has been proposed in which the rolling-down position of each stand is set in advance based on a theoretical formula. Because the set thickness calculation method is different, the set thickness when passing through the stand thickness gauge and the measured thickness error at that stand do not equal the final set thickness and the final thickness error.

In order to solve this problem, Japanese Patent Laid-Open No. 3-1
In JP-A-51109 and JP-A-5-55205, a plate thickness gauge is provided between intermediate stands instead of the exit side of the final stand, and the actual sheet thickness is measured when the material to be rolled passes this thickness gauge. There is proposed a method of measuring and measuring the plate thickness on the downstream side based on the measured plate thickness to set the rolling position.

However, it is not possible to accurately estimate the final delivery side plate thickness only by the information based on the plate thickness between stands. Further, in estimating the final delivery side plate thickness, it is not possible to accurately estimate the plate thickness information of the preceding stage for one stand.

[0006]

However, in the method disclosed in Japanese Unexamined Patent Publication No. 5-55205, each element for performing the finish setting calculation is not accurately obtained, so that the plate thickness deviation which appears In addition, since there is a contradiction in that the factor separation is performed using each element, there is a problem that the plate thickness accuracy is not improved even if the gap and speed of the downstream stand are corrected. The problem to be solved by the present invention is to improve the plate thickness accuracy by using reliable information and actual values without using each element having such variations and ambiguity as much as possible.

[0007]

In order to solve the above-mentioned problems, a first strip thickness control method of the present invention is a strip thickness control method for a hot continuous rolling mill having a plurality of stands. An intermediate stand thickness gauge and a final exit thickness gauge are provided on the output side, respectively, and the thickness deviation of the thickness measured by the intermediate stand thickness gauge and the gauge gauge thickness of the stand immediately after the intermediate stand thickness gauge are measured. From this, the plate thickness deviation due to the final output side plate thickness gauge is estimated, and the bias amount is corrected from the past control record and the present inter-stand plate thickness record, so that two or one stands downstream of the intermediate stand plate gauge can be corrected. It is supposed to correct the gap and peripheral speed.

A second strip thickness control method is a strip thickness control method for a hot continuous rolling mill having a plurality of stands, wherein an intermediate stand strip thickness gauge and a final strip thickness gauge are provided between the stands and on the exit side of the final stand, respectively. Is provided, and the final deviation of the thickness gauge from the final output side thickness gauge is obtained from the thickness deviation due to the thickness gauge actual result measured by the intermediate stand thickness gauge and the gauge deviation of the stand immediately after the intermediate stand thickness gauge and the load deviation based on the measured load. By estimating the plate thickness deviation due to the above, and further correcting the bias amount from the past control results and the present inter-stand plate thickness results, the gap and peripheral speed of the two or one stands downstream of the intermediate stand thickness gauge are corrected. I have decided.

[0009]

In the first means of the present invention, the ratio of the set thickness and the thickness error is not used, but the information of the thickness error by the stand-to-stand thickness gauge and the thickness error by the final exit side thickness gauge are directly used. . Also, the plate thickness error of this stand is estimated from the load of the stand immediately after the stand thickness gauge, using a highly accurate gauge meter type. Estimate the plate thickness error by the final output side plate thickness gauge from the multiple regression equation of the two information of the plate thickness error by the stand thickness gauge and the plate thickness error by the gauge meter formula. Perform plate thickness correction operation.

In the second means, similarly, the ratio between the set plate thickness and the plate thickness error is not used, but the information on the plate thickness error by the stand-to-stand plate thickness meter and the plate thickness error by the final exit side plate thickness meter are directly used.
In addition, the gauge thickness and the load deviation immediately after the stand thickness gauge are used. The thickness error due to the final thickness gauge is estimated from the multiple regression equation of the three information of the thickness error due to the thickness gauge between stands, the thickness error due to the gauge meter thickness and the load deviation, and the estimation error is divided by the remaining stands. The plate thickness correction operation is performed.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 1 is a block diagram showing a first embodiment in which the present invention is applied to plate thickness control of a 7-stand hot rolling mill. In the figure, F5, F6 and F7 are 5 respectively.
No. 6, No. 6, No. 7 stand, 1 is a strip, 2 is a stand thickness gauge installed between the No. 4 stand and No. 5 stand, and 3 is a final exit side thickness gauge installed on the exit side of the final stand. Indicates.

In FIG. 1, a plate thickness error is learned by using a plate thickness gauge 2 between stands and a final output side plate thickness gauge 3. That is, the relationship between the plate thickness deviation Δh ₄ by the inter-stand plate thickness meter 2 and the plate thickness deviation Δh ₇ by the final delivery side plate thickness meter 3 when this setup is not performed is plotted as shown in FIG. 2 (A).
Furthermore, the plate thickness is estimated by the load immediately after the stand thickness gauge, and the plate thickness error is learned. That is, the thickness deviation Δh ₅ by the gauge meter type of the stand immediately after the inter-stand thickness gauge (5th stand F5 in this example) and the thickness deviation Δh ₇ by the final exit side thickness gauge 3 when this setup is not performed. The relationship is plotted as shown in FIG. Here, the gauge meter (GM) formula is represented by the following formula.

Δh _GM = S + AMe−ΔS _OIL + GME−h _FSU (Δh _GM : Estimated plate thickness deviation, S: Roll gap, A: Coefficient, Me: Mill stretch amount, ΔS _OIL : Oil film thickness, G
(ME: Gauge meter error, h _FSU : FSU setting plate thickness)

From the results of FIGS. 2 (A) and 2 (B), a multiple regression equation with the final delivery side plate thickness deviation is created, and the final plate thickness deviation is estimated based on the following plate thickness estimation model.

[0015] _Δh 7est _{(estimate) = αΔh 4 + βΔh 5GM (} GM type)
+ Γ (bias) (α, β, γ are the coefficients of the multiple regression equation, respectively)

The final output side plate thickness error is estimated by the regression equation of the above-mentioned measured plate thickness error and estimated plate thickness error, and the gap tightening amount corresponding to the estimated plate thickness error is calculated, and the 6th and 7th stand Fix the gap. However, for variations that do not lie on the multiple regression plane, the control effect diminishes, so the bias amount γ is set to the final output side plate thickness deviation measured value DΔ of the previous control execution word.
h _{7 (i-1)} , the actual measured value of the final delivery side plate thickness deviation D Δh _{7 (i-2)} after the previous control, and the previous stand-to-stand plate thickness deviation Δ
h _{4 (i-1)} , as a functional system of the stand-to-stand plate thickness deviation Δh _{4 (i)} used to control this time, the final (i) th final outlet side plate thickness deviation estimated value is

Δh _{7est (i)} = αΔh _{4 (i)} (measured value) + βΔh 5GM _(i) + γ _{0 (i)} (bias initial value) + γ _{1 (i)} (bias feedback proportional value) + γ _{2 (i)} ( Bias feedback integrated value) + γ _{3 (i)} (Bias feedback differential value) where γ _{0 (i)} = γ _{0 (i-1)} γ _{1 (i)} = G ₁ {α ₁ · DΔh _{7 (i-1)} ＋ (1−α ₁ ) ・ DΔ
h _{7 (i-2)} } γ _{2 (i)} = γ _{2 (i-1)} + G ₂ {α ₂ · D Δh _{7 (i-1)} + (1−α ₂ ) · D
Δh _{7 (i-2)} } γ _{3 (i)} = G ₃ (Δh _{4 (i)} −Δh _{4 (i-1)} ), and the variation on the regression plane is absorbed. The flow of the above processing is shown in FIG.

According to the results of experiments employing the method of this embodiment, the on-gauge ratio of ± 50 mm was 63% for a certain steel type in the past, but the simulation result shown in FIG. 3 shows an on-gauge ratio of 84.8%. , A remarkable improvement effect appeared.

FIG. 5 is a block diagram showing a second embodiment of the present invention. The difference from the first embodiment is that the first embodiment estimates with two parameters, the measured plate thickness Δh ₄ on the exit side of the No. 4 stand and the plate thickness deviation Δh _5GM by the gauge meter type of the No. 5 stand. In the second embodiment, in addition to the measured plate thickness deviation Δh ₄ on the No. 4 stand exit side and the plate thickness deviation Δh _5GM of the No. 5 stand by the gauge meter type, the load deviation is used to determine 3
It is a point to be estimated with one parameter.

A detailed description will be given below. Similar to the first embodiment, the relationship between the plate thickness deviation Δh ₄ by the inter-stand plate thickness meter 2 and the plate thickness deviation Δh ₇ by the final exit side plate thickness meter 3 when this setup is not performed is shown in FIG. To plot. Further, the load P ₅ of the No. 5 stand F5, which is the stand on the outgoing side of the inter-stand thickness gauge 2, is measured with a load cell, and the load deviation ΔP ₅ and the outgoing plate thickness deviation Δh ₅ of the No. 5 stand are obtained from this.

Next, the plate thickness error due to the final plate thickness gauge is estimated from the multiple regression equation of three pieces of information of the plate thickness error due to the inter-stand plate thickness gauge, the plate thickness error due to the gauge meter plate thickness, and the load deviation, and the remaining The thickness correction operation for the estimated error is performed on the stand.

Δh _7est (estimated value) = αΔh ₄ (measured value)
+ ΒΔh _5GM (GM type) + γΔP ₅ (measured value) + [delta] (bias)

However, for variations that do not lie on the multiple regression plane, the control effect diminishes, so the bias component γ is set to the final output side plate thickness deviation measured value DΔh _{7 (i-1)} of the previous control execution word,
Actual measured value of final delivery side thickness deviation DΔh after the control two times before
_{7 (i-2)} , previous stand thickness deviation Δh _{4 (i-1)} , this time,
As a function system of the stand-to-stand plate thickness deviation Δh _{4 (i)} used for control, the final output side plate thickness deviation estimated value at this time (the i-th time) is

Δh _{7est (i)} = αΔh _{4 (i)} (measured value) + βΔ
h 5GM _(i) + γΔP _{5 (i)} (measured value) + δ _{0 (i)} (bias initial value) + δ _{1 (i)} (bias feedback proportional value) + δ _{2 (i)} (bias feedback integral value) + δ _{3 (i )} (Bias feedback differential value) where δ _{0 (i)} = δ _{0 (i-1)} δ _{1 (i)} = G ₁ {α ₁ · DΔh _{7 (i-1)} + (1−α ₁ ) · DΔ
h _{7 (i-2)} } δ _{2 (i)} = δ _{2 (i-1)} + G ₂ {α ₂ · D Δh _{7 (i-1)} + (1−α ₂ ) ・ D
_{Δh 7 (i-2)}} δ 3 (i) = G 3 (Δh 4 (i) -Δh 4 (i-1)) and then, to absorb the variation in the regression plane.

A plate thickness estimation model for estimating the final delivery side plate thickness is created from the multiple regression equation. The flow of the above processing is shown in FIG.
Shown in.

According to the result of the experiment using the method of the present embodiment, the on-gauge ratio of ± 50 mm is 63% for a certain steel type in the past, but the simulation result shows the on-gauge ratio of 85.5%, which is a remarkable improvement effect. Appeared.

[0027]

As described above, according to the present invention, utilizing the measurement results of the stand stand thickness gauge and the final exit side thickness gauge,
By dynamically feed-forwarding the rolling results of the former stand to the latter stand, the plate thickness accuracy of the coil tip portion is improved, and the cut-off amount of the plate thickness unmatched portion can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a graph plotting the relationship between the plate thickness deviation of the intermediate stand and the final delivery side plate thickness deviation.

FIG. 3 is a graph showing the effect of improving the on-gauge ratio according to the present invention.

FIG. 4 is a flowchart of the process of the first embodiment.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a flowchart of the process of the second embodiment.

[Explanation of symbols]

1 strip, 2 stand thickness gauge, 3 final exit thickness gauge

Claims (2)

[Claims] 1. A sheet thickness control method for a hot continuous rolling mill having a plurality of stands, wherein an intermediate stand sheet thickness gauge and a final outlet sheet thickness gauge are provided between the stands and at the final stand outlet side, respectively, and the intermediate stand sheet thickness is provided. The thickness deviation due to the actual thickness gauge measured by the gauge and the gauge thickness of the stand immediately after the intermediate stand thickness gauge are used to estimate the thickness deviation due to the final output side thickness gauge. 2 or 1 downstream of the intermediate stand thickness gauge by correcting the bias amount from the actual stand thickness
A plate thickness control method characterized by correcting a gap and a peripheral speed of a stand. 2. A sheet thickness control method for a hot continuous rolling mill having a plurality of stands, wherein an intermediate stand sheet thickness gauge and a final outlet sheet thickness gauge are provided between the stands and at the final stand outlet side, respectively, and the intermediate stand sheet thickness is provided. From the thickness deviation due to the actual thickness gauge measured by a meter and the gauge deviation of the stand immediately after the intermediate stand thickness gauge and the load deviation based on the measured load, the thickness deviation due to the final delivery side thickness gauge is estimated, Further, the plate thickness control is characterized in that the gap and the peripheral speed of two or one stands downstream of the intermediate stand plate thickness gauge are corrected by correcting the bias amount based on the past control results and the present inter-stand plate thickness results. Method.