JP2008183583A - Method of controlling finished plate width of hot-rolling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling the finished plate width of hot-rolling which is excellent in the responsiveness of plate width control in the control of the finished plate width of hot-rolling by which the plate width control of a rolled stock is performed by controlling interstand tension with a hot finishing mill having a plurality of rolling stands and loopers between the stands. <P>SOLUTION: The amount of plate width correction is dynamically changed by performing the calculation of the amount of the plate width correction before performing the calculation of the amount of tension change in each looper. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to hot strip finishing plate width control for controlling the strip width of a rolled material by controlling the tension between the stands with a hot rolling finish rolling mill having a plurality of rolling stands and a looper between the stands.

  As a method for controlling the sheet width of a steel sheet to a desired value with a hot continuous rolling mill, for example, techniques disclosed in Patent Document 1 and Patent Document 2 are known.

  In Patent Document 1, a plate width deviation between a plate width measured with a plate width meter installed on the exit side of the i-th stand of a rolling mill and a target plate width is obtained, and the tension is changed to correct the plate width. In the feedback control system for causing the plate width to follow the target plate width, the tension between the stands corresponding to the plate width deviation is changed only at the i-th stand, and the correction according to the tension change at the i-th stand is performed. The system implemented by the i-1th stand is proposed.

Further, Patent Document 2 discloses that at least an upstream tension between two stands or more in order to eliminate deviations in plate width and thickness measured by an intermediate plate width meter / intermediate plate thickness meter installed between downstream stands. Thus, a system is proposed in which the plate width is corrected by a plurality of loopers by dynamically controlling by a feedback system.
JP-A-2-235511 JP 2000-32005 A

  However, since the method of Patent Document 1 basically attempts to correct the plate width only by the i-th stand, there is a limit to the amount of control. And since the responsiveness from detecting the deviation to making the deviation zero is poor and control cannot be performed over the entire length of the rolled material, there is a problem that the defective portion with the deviation remaining becomes long. It was.

  Japanese Patent Laid-Open No. 2004-228688 dynamically feedback-controls looper tension between a plurality of stands. Compared to the control in one stand of Patent Document 1, the amount of control increases, but the rolling material reaches the desired plate width from the place where all the target loopers have passed, and the response of the plate width control is slow. In addition, there remains a problem that there is no specific description about how to distribute the looper.

  The present invention has been made in view of the above circumstances, and hot rolling finishing that controls the sheet width of a rolled material by controlling the tension between the stands with a hot rolling finishing mill having a plurality of rolling stands and a looper between the stands. An object of the present invention is to provide a hot-rolled finished sheet width control method with good sheet width control responsiveness in sheet width control.

  The invention according to claim 1 of the present invention is a hot rolled finish plate width for controlling the plate width of a rolled material by controlling the tension between the stands by a hot roll finish rolling mill having a plurality of rolling stands and a looper between the stands. In the control, the hot strip finish plate width control method is characterized in that the plate width correction amount is calculated and dynamically changed before calculating the tension change amount in the looper.

  Furthermore, the invention according to claim 2 of the present invention is the hot rolled finished plate width control method according to claim 1, wherein the change in the plate width correction amount is determined by the finished delivery side plate width and the target measured by a finished delivery side plate width meter. A hot-rolled finished sheet width control method, which is performed based on a width deviation from a sheet width and a rolled material travel distance.

  In the present invention, since the looper distribution is dynamically changed according to the distance traveled by the rolled material, the response of the sheet width control can be improved.

  The cause of poor responsiveness of the prior art is that the distribution ratio to each looper is controlled to a constant value (invariable) even if the plate width is corrected with multiple loopers and the control amount is increased. The present invention has been conceived and conceived. Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 5 is a diagram showing an outline of a conventional finishing tension AWC (Automatic Width Control) which is an object of the present invention. In this example, the plate width correction for each looper (here, applied to the 4 loopers downstream of the F3 to F6 loopers) based on the width deviation between the finish plate width measured with the finish width meter and the target plate width. Based on the calculated tension change amount, the tension is changed by each looper to realize feedback control of the plate width.

  FIG. 6 is a diagram illustrating an example of calculation of the plate width correction amount for each looper. In this example, it is assumed that a deviation of 10 mm occurs as measured by the finishing width meter, and this 10 mm deviation is removed, and constant weighting is performed for each looper. In other words, the plate width correction amount is sequentially output as 4 mm, 3 mm, 2 mm, and 1 mm for each looper so that the deviation of 10 mm is sequentially reduced to 6 mm, 3 mm, 1 mm, and 0 mm. ing.

  Thus, in order to finally remove the deviation of 10 mm, the length from the finishing width meter to the F4 looper (for example, 20 m) is required, and there is a problem that the response of the correction of the plate width is slow.

In contrast, in the present invention, the following method is used. First, FIG. 1 is a diagram showing the overall configuration of a control method and apparatus according to the present invention. Similar to FIGS. 5 and 6, when the tension is changed at each looper after the F3 stand, the width deviation between the finishing plate width measured by the finishing plate width meter and the target plate width is used. The PLG that measures the main stand speed of the final stand F7 is installed, the rolling speed is calculated by regarding the mill speed as the rolling material speed, and the rolled distance L and the sheet width deviation are the same. A difference is that ΔW _L is associated with each other.

Then, the sheet width correction amount is calculated before calculating the tension change amount in each looper using the rolled distance L and the sheet width deviation ΔW _L that are associated with each other.

  First, calculation of the plate width correction amount W in the F3 looper and the plate width correction amount W in the F4 to F6 loopers is performed by the following equations (1) and (2), respectively.

2A shows a correspondence table image (a) between the rolled distance L and the sheet width deviation ΔW _L , and FIG. 2B shows a correction gain G (L) corresponding to the distance. It is. In the figure, (a) shows a state in which the rolled distance L and the sheet width deviation ΔW _L are associated with each other. In (b), the correction gain G (L) is 1 when the distance is 0. Is shown as a function having a value of ₀ after a length L ₀ between one stand.

  As described above, the calculation of the plate width correction amount W by the F4 to F6 loopers is multiplied by the correction gain corresponding to the distance so as to increase the responsiveness. FIG. 2B shows an example of the function shape of the correction gain G (L). However, it is preferable that the correction gain G (L) is appropriately selected in consideration of the responsiveness of the target device.

  FIG. 3 and FIG. 4 are diagrams showing calculation examples of the sheet width correction amount W according to the present invention, each of which shows a state immediately after the deviation has occurred and immediately after the rolled material has advanced one stand length (= 5.6 mm). Show. Similar to the above example, a deviation of 10 mm is generated and removed. Immediately after the deviation of FIG. 3 occurs, the plate width correction amounts W in the F3 to F6 loopers are all 10 mm, but thereafter F4 to F6. The plate width correction amount W at the looper is gradually reduced as calculated by the equation (2), and immediately after proceeding by one stand length (= 5.6 mm) shown in FIG.

  In the present invention, to remove the deviation of 10 mm, the distance from the finishing side width meter to F7 (for example, 3 m) is sufficient. In the above example, the distance to the upstream stand (from the finishing side width meter to the F4 looper). Responsiveness can be improved as compared with the case where the required length (for example, 20 m) is required. Further, the F6 looper, which is close to the finish side width meter, has a surplus force, and further width control is possible (that is, it is not saturated even for a long time).

It is a figure which shows the whole structure of the control method and apparatus concerning this invention. It is a figure explaining the correspondence table image (a) and correction | amendment gain (b). It is a figure which shows the example of calculation of the board width correction amount by this invention (just after a deviation arises). It is a figure which shows the example of calculation of the board width correction amount by this invention (immediately after having advanced 1 stand length). It is a figure which shows the outline | summary of the conventional finishing tension AWC. It is a figure which shows an example in the board width correction amount calculation for every looper.

Claims (2)

In the hot rolling finishing plate width control for controlling the plate width of the rolled material by controlling the tension between the stands with a hot rolling finishing mill having a plurality of rolling stands and a looper between the stands,
A hot-rolled finishing plate width control method characterized by calculating a plate width correction amount and dynamically changing the plate width correction amount before calculating the tension change amount in the looper. In the hot rolled finishing board width control method according to claim 1,
The change of the plate width correction amount is
A hot rolled finished sheet width control method, which is performed based on a width deviation between a finished sheet width and a target sheet width measured by a finishing sheet width meter, and a rolled material travel distance.

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