JP4181000B2 - Method for identifying deformation characteristics of sheet rolling mill and sheet rolling method using the same - Google Patents

Description

  The present invention relates to a method for identifying deformation characteristics of a plate rolling machine that rolls a metal sheet such as a steel plate and a sheet rolling method using the same, and in particular, the deformation characteristics of a plate rolling machine that can optimize the setting and control of the rolling device. The present invention relates to an identification method and a plate rolling method using the identification method.

One of the important issues in the rolling operation of a metal plate material is to make the elongation rate of the rolled material equal between the working side and the driving side. In the following description, the working side and the driving side are referred to as left and right for the sake of simplicity.
If the elongation becomes uneven on the left and right, not only the flat shape and dimensional accuracy of the rolled material such as the camber or the plate thickness wedge may be caused, but also a plate trouble such as meandering and bottom squeezing may occur.
As an operation means for equalizing the left and right elongation, elimination of the left-right difference in the rolling position of the rolling mill, that is, a rolling leveling operation is used. Normally, the rolling leveling operation is mostly performed by the operator while carefully observing the rolling operation for both the setting before rolling and the operation during rolling. We could not control the threading trouble sufficiently.

With respect to the above problem, Patent Document 1 discloses a technique for performing the reduction leveling control based on the ratio of the load cell load of the rolling mill to the sum of the left and right differences.
Patent Document 2 discloses a technique for manipulating the reduction leveling by directly detecting the deviation of the rolling material on the entry side of the rolling mill, that is, the amount of meandering.
The techniques for making the difference between the left and right elongation ratios of the rolled material exemplified here zero optimize the reduction leveling as the control means. This is a feedback-type control technique in which a difference occurs between the left and right and an action is taken after it is detected as meander or camber of the rolled material. In the case of this type of control, there is a significant time delay between the occurrence of a left-right difference in the elongation rate of the rolled material and the detection of this as meandering or camber. And the camber problem was not fully solved.

Patent Literature 3 and Patent Literature 4 are disclosed as technologies that may solve the problems of the above technology. Unlike the above-mentioned feedback method, these technologies accurately grasp the left-right asymmetry of the deformation characteristics of the rolling mill, and also accurately determine the left-right asymmetry of the deformation characteristics such as the dimensions of the rolling material and deformation resistance. It is an object of the present invention to realize an operation that does not generate meandering or camber from the start of rolling of the rolling material head by optimally setting a rolling set value before starting rolling.
Japanese Patent Publication No. 58-51771 JP 59-191510 A Japanese Patent No. 2604528 JP-A-11-347610

In Patent Document 3, in particular, in order to identify the left-right asymmetry of the deformation characteristics of the rolling mill, the kiss rolls are tightened by operating the reduction device, the reduction positions on the working side and the driving side, and the load cell for measuring the rolling load. Output for a plurality of rolling position conditions, calculate and separate the deformation of the roll system corresponding to each rolling position condition, and as a result, the left and right asymmetry of the deformation characteristics of the rolling mill housing and the rolling system A technique has been disclosed in which the optimum reduction leveling setting is performed by utilizing the deformation characteristics of the rolling mill thus obtained. Here, kiss roll tightening means that the upper and lower work rolls are brought into contact with each other in a state where no rolling material is present, and a load is applied between the rolls.
However, when the technique disclosed in Patent Document 3 was implemented, depending on the rolling mill, sufficient reproducibility may not be seen in the deformation characteristics of the identified rolling mill housing and the rolling reduction system. As a result, it has not been possible to sufficiently prevent the occurrence of meandering and camber.

As a technique that can improve this problem, in Patent Document 4, in order to eliminate the influence of the inter-roll thrust force that occurs when the kiss roll is tightened, the kiss roll is tightened in the roll rotation stop state, and the rolling mill housing and A method of identifying the left-right asymmetry of the deformation characteristics of the rolling reduction system and utilizing the deformation characteristics of the rolling mill thus obtained to perform an optimal rolling leveling setting is disclosed.
However, this method can eliminate the influence of the thrust force between rolls by tightening the kiss roll while the roll rotation is stopped. The roll deformation is changed by the resistance, and there is a problem that an error occurs in the deformation characteristics of the identified rolling mill housing and the rolling system.

  Therefore, the present invention eliminates the influence of the thrust force between the rolls and identifies the frictional resistance between the rolls when identifying the deformation characteristics of the rolling mill housing and the reduction system by the kiss roll tightening test in the roll rotation stop state. By eliminating the error, it is possible to identify the rolling mill housing and the deformation characteristics of the rolling system with higher accuracy than before, and the rolling position setting and / or the rolling position control of the plate rolling mill using the results is effective. It is an object of the present invention to provide a method for identifying deformation characteristics of a sheet rolling mill and a sheet rolling method using the same.

In the present invention, when the deformation characteristics of the rolling mill housing and the rolling system are identified by a kiss roll tightening test in a roll rotation stopped state, the roll rotation is stopped for each rolling position condition to release the frictional resistance between the rolls, and then the roll rotation is stopped. By collecting the rolling position and load data in the state, eliminating the influence of the thrust force between the rolls, and eliminating the identification error due to the frictional resistance between the rolls, It became possible to identify the deformation characteristics of the rolling reduction system, and found that it was possible to effectively perform the rolling position setting and / or the rolling position control of the sheet rolling machine utilizing the results, The gist of the present invention is as follows, as described in the claims.
(1) Rolling load provided on the working side and the drive side of the plate rolling machine with respect to a plurality of rolling position conditions by operating the rolling reduction device with the roll rotation stopped to tighten the kiss roll of the plate rolling machine. Identification of deformation characteristics of a plate mill that simultaneously collects output values of the measuring device and measured values of the work side and drive side reduction positions and calculates the deformation characteristics of the rolling mill housing and reduction system on the work side and drive side. In the method, the roll rotation is stopped after rotating the roll for each rolling position condition to release the frictional resistance between the rolls, and the output value of the rolling load measuring device and the measured value of the rolling position are collected. A method for identifying deformation characteristics of a plate mill.
(2) Based on the deformation characteristics of the rolling mill housing and the rolling system on the working side and the driving side identified by the deformation characteristic identifying method for the plate rolling mill described in (1), the working side and the driving side at the time of rolling are performed. A sheet rolling method characterized by calculating a reduction position setting value and / or a reduction position control amount.

  By adopting the method for identifying the deformation characteristics of the sheet rolling mill of the present invention and the sheet rolling method using the same, it is possible to deform the rolling mill housing and the rolling system with high accuracy by eliminating the influence of the thrust force between rolls and the frictional resistance between rolls The characteristics can be identified, and the optimal reduction position can be set and controlled based on the identification results. As a result, the frequency of occurrence of meandering and threading troubles in rolling operations can be greatly reduced, and further rolling Since the plate thickness accuracy of the material can be improved and the camber and the plate thickness wedge can be significantly reduced, it is possible to simultaneously achieve cost reduction and quality improvement required for rolling.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 3 is a view showing a side view on the working side of a four-high rolling mill as a rolling mill to which the deformation characteristic identifying method for a plate rolling mill according to the present invention is applied.
This four-high rolling mill is merely an example, and it goes without saying that the present invention can be applied to a five-high rolling mill or a six-high rolling mill in which an intermediate roll is further added.

  In FIG. 3, the rolling mill 1 comprises work rolls 3a and 3b rotatably supported via housing roll chocks 5a and 5b and reinforcing roll chocks 6a and 6b, and reinforcing rolls 4a and 4b. A four-high rolling mill is configured. The housing 2 is provided with a pair of left and right, that is, a work-side and drive-side reduction devices 8, and controls the gap between the upper and lower work rolls 3 a and 3 b. Rolling load measuring devices 7 are arranged at the left and right rolling fulcrum positions of the upper and lower reinforcing rolls. Although FIG. 3 shows the increment work roll bending apparatuses 9a and 9b and the decrease work roll bending apparatuses 10a and 10b, the deformation characteristic identification method for the sheet rolling mill of the present invention and the rolling method using the same Is not an essential requirement. Reference numeral 11 denotes a passline height adjusting liner.

In addition to the left-right asymmetry of the rolling load distribution between the rolling material and the work roll, for example, in the case of a four-high rolling mill, between the work roll and the reinforcing roll, In the case of a six-high rolling mill, the thrust force acting in the roll axial direction is included as the largest factor between the work roll and the intermediate roll and between the intermediate roll and the reinforcing roll. The thrust force acting between these rolls gives an extra moment to the rolls, and the difference between the left and right rolling load changes to balance this moment, so the work side and drive side reduction positions and the load cell load for measuring the rolling load When identifying the left-right asymmetry of the deformation characteristics of the rolling mill housing and the rolling system using the measured values as basic data, it becomes a significant error factor.
The main cause of the thrust force between the rolls described above is that the rotation axes of adjacent rolls are shifted from the parallel position by a slight gap between the roll chock and the housing window when they come into contact with each other. When an error occurs in the parallelism between adjacent roll axes as described above, a deviation component in the roll axis direction is generated in both roll peripheral speed vectors accompanying the roll rotation. Thus, slip in the roll axis direction is always generated, and the force generated by such slip is the inter-roll thrust force.

With respect to such a disturbance of thrust force, the method of Patent Document 4 described above discloses a method of performing kiss roll tightening in a roll rotation stop state and identifying deformation characteristics of the rolling mill housing and the reduction system. As described above, since the thrust force between the rolls is generated with the rotation of the roll, in the method of Patent Document 4, the kiss roll is tightened in the roll rotation stop state, so that the inter-roll thrust force is substantially generated. Therefore, the influence of disturbance on the load cell for measuring the rolling load can be eliminated.
However, in this method, since the kiss roll is tightened in the roll rotation stopped state, the roll deformation changes due to wear resistance between the rolls, such as when the friction coefficient of the roll surface is high, and the identified rolling mill housing and reduction system There is a problem that an error is introduced in the deformation characteristics. FIG. 4 shows the direction of roll axial displacement between the reinforcing roll and the work roll when roll deflection occurs. Since these displacement directions are opposite directions between the reinforcing roll and the work roll, a frictional resistance is generated between the rolls, and the roll deformation is changed. If the roll friction coefficient is left-right asymmetric, the change in roll deformation is not only left-right asymmetric, but the friction force in the roll axis direction acting between the rolls is not balanced left and right, giving an extra moment to the roll. The deformation characteristics of the identified rolling mill housing and the rolling system also have an asymmetric error. Such frictional resistance between rolls occurs because roll rotation is in a stopped state due to changes in roll deflection with increasing tightening load, and the rolls are slightly rotated to slide the contact portions between the rolls. It was found from the detailed examination by the present inventors that the release is possible.

Next, a method for identifying deformation characteristics of a sheet rolling mill according to an embodiment of the present invention and a rolling method using the same will be described with reference to FIGS.
FIG. 1 is a flow chart showing an algorithm of a preferred first embodiment, which is a method for identifying deformation characteristics of a sheet rolling mill according to claim 1 of the present invention. Such identification of the deformation characteristics of the sheet rolling mill is necessary as a preparatory work before starting the rolling work, and is preferably performed every time the reinforcing roll is recombined.

First, the reduction device is operated in the left and right simultaneous reduction mode with the roll rotation stopped, and is tightened to a predetermined reduction position with the kiss roll tightened (step S10). Here, the left and right simultaneous reduction mode is an operation mode in which the left and right reduction positions are changed by the same amount in the same direction while the left-right difference between the reduction positions, that is, the reduction leveling is fixed. As long as the system is operated in the simultaneous reduction mode, the reduction leveling does not change. Next, while the roll rotation is stopped, the reduction device is tightened by a certain amount in the right and left simultaneous reduction mode, and then the roll is slightly rotated to release the frictional resistance between the rolls (step S11). The amount of roll rotation at this time is calculated by, for example, estimating the change in deflection of the work roll due to the increase in tightening load and the change in deflection of the reinforcement roll, and the slip distance in the roll axis direction required at the contact portion between the work roll and the reinforcement roll. It may be obtained by calculation. Alternatively, the cross-roll cross angle at the allowable thrust force is calculated from the relationship between the cross-roll angle and the thrust force, and the rotation distance necessary to digest the slip distance in the thrust direction (roll axis direction) is calculated and obtained. May be. Next, roll rotation is stopped, and the output values of the left and right rolling positions and the left and right rolling load measuring devices are collected in this state (step S12). Steps S11 to S13 are repeated until data collection for a predetermined rolling position level is completed. That is, in step S13, it is determined whether or not data collection is complete. If No, the algorithm returns to step S11, and if Yes, the process proceeds to step S14. At this time, the number of rolling position levels requires at least two levels of data including the load that can be realized by tightening the kiss roll, and usually the kiss roll is tightened at a rolling position level of about 10 to 20 points. It will be. However, at this time, there is often a so-called mill hysteresis that causes a difference in tightening load between the direction in which the reduction device is tightened and the direction in which it is released. In such a case, at least the tightening direction and the opening direction are at least It is preferable to collect data for one reciprocating motion and perform an operation such as averaging both measured data, for example.

  Next, using the kiss roll tightening data collected in steps S11 to 13, that is, the output values of the left and right rolling load measuring devices for each rolling position condition, the deformation amount of the reinforcing roll and the work roll in each rolling position condition ( Calculation is performed including the difference between right and left of the roll deflection and roll flatness), and the deformation amount of the roll system for each reduction position condition is calculated (step S14). In this way, the method for specifically calculating the deformation amount of the roll system is such that the load distribution between the rolls is obtained from the calculation result of step S14 by the method disclosed in Japanese Patent Publication No. 4-74084. Therefore, it is possible to calculate including the left-right difference between the deflection deformation and the flat deformation of the reinforcing roll and the work roll, and it is possible to calculate the displacement generated at the reduction fulcrum position of the reinforcing roll as a result of these deformations.

Next, the deformation amount of the rolling system in step S14 is subtracted from the deformation amount of the entire rolling mill at the reduction fulcrum position evaluated by the change in the reduction position of the kiss roll tightening data, and the deformation characteristics of the housing and the reduction system are independently determined on the left and right sides. Calculation is performed (step S15). Since the deformation amount of the entire rolling mill is evaluated by the change in the reduction position, the deformation amount of the roll system at the reduction fulcrum position is subtracted from this, and the deformation characteristics of the housing and the reduction system are independently calculated. If the deformation amounts of the housing and the rolling system on the working side and the driving side are Δ ₀ ^W and Δ ₀ ^D, and the output values of the rolling load measuring device on the working side and the driving side are P _W and P _D , Δ ₀ ^W and Δ ₀ ^D can be expressed as discrete functions as follows:
Δ ₀ ^W = Δ ₀ ^W (P _W ) (1)
Δ ₀ ^D = Δ ₀ ^D (P _D ) (2)
As described above, in the method for identifying the deformation characteristics of the sheet rolling mill according to claim 1 of the present invention, the influence of the thrust force between the rolls can be eliminated and the identification error due to the frictional resistance between the rolls can be eliminated. In comparison, it is possible to identify the deformation characteristics of the rolling mill housing and the rolling system with higher accuracy.

FIG. 2 is a flowchart showing the algorithm according to the second preferred embodiment of the rolling method of the plate rolling mill according to claim 2 of the present invention, and the rolling mill obtained by the identification method according to claim 1 of the present invention. An example of a reduction position setting and a reduction position control method implemented using the deformation characteristics of the housing and the reduction system is shown.
In the present embodiment, the deformation characteristics of the rolling mill housing and the rolling reduction system are obtained independently on the left and right sides in the same procedure as in the first embodiment (steps S20 to S25).
Based on the deformation characteristics of the rolling mill housing and the rolling system, the rolling position setting value and / or the rolling position control amount on the working side and the driving side during rolling are calculated (step S26).

As described above, in the method according to the second embodiment of the present invention, the rolling mill housing and the reduction characteristics of the rolling system that exclude the influence of the thrust force between the rolls and the frictional resistance between the rolls are used to identify the rolling mill. Since the right and left deformation characteristics are accurately grasped and the reduction position is set before rolling, it is possible to achieve higher accuracy than the rolling material head in both the plate width central plate thickness and the plate thickness wedge, and meandering And stable and high-precision rolling operation without causing camber.
In addition, during the rolling operation after the start of rolling, variations in plate thickness, meandering, and plate thickness wedges occur due to various causes. In order to control this, the change in the output value of the rolling load measuring device installed in the rolling mill is observed, and the plate thickness and the plate thickness wedge amount are estimated from this, and this is dynamically changed to the desired value. The method of controlling is applied. When performing such control, it is necessary to calculate the amount of change in rolling mill deformation accompanying the change in rolling load, including the left-right asymmetry of the deformation characteristics of the rolling mill as in the method of the present invention. By accurately grasping, the effect of the above-described reduction control is greatly improved.

The actual hot strip mill finish rolling mill No. having the same function as the rolling equipment shown in FIG. An example in which the deformation characteristic identification method and rolling method of the present invention are applied to 7 stands will be described.
A comparison between the conventional method and the method of the present invention was performed regarding the identification of the deformation characteristics of the plate rolling machine and the setting of the rolling position performed before rolling. First, according to the conventional method, the kiss roll is tightened in the roll rotation stop state at the time of non-rolling before rolling, the work side and drive side reduction positions and the output value of the rolling load measuring device are collected, and this kiss roll tightening data From the above, the deformation characteristics of the left and right rolling mill housings and the rolling reduction system were identified. The identification result is shown in FIG.
Based on the deformation characteristics of the rolling mill housing and the rolling system, No. For 7 stands, the rolling position was set before rolling. As a result, when a thin wide material having an outlet side thickness of 1.2 mm and a width of 1200 mm was rolled, a thickness wedge was generated and narrowing occurred due to meandering when the tail end portion was passed.

  On the other hand, in the method of the present invention, when tightening the kiss roll in the roll rotation stop state according to the procedure shown in the first embodiment, the roll is rotated for each rolling position condition to release the frictional resistance between the rolls. The data were collected from this, and the deformation characteristics of the left and right rolling mill housings and the rolling system were identified from the kiss roll tightening data. FIG. 6 shows the identification result.

Based on the deformation characteristics of the rolling mill housing and the rolling system, No. For 7 stands, the rolling position was set before rolling. As a result, even when a thin material having a thickness of 1.2 mm and a width of 1200 mm, which had been narrowed down by the conventional method, was rolled, it was possible to allow the rolled material to pass straight through the rolling line with little occurrence of thickness wedge. .
As described above, according to the method of the present invention, the deformation characteristics of the rolling mill housing and the rolling system that exclude the influence of the thrust force between rolls and the frictional resistance between rolls are identified, and based on the identification result, before rolling starts. It has been proved that a stable rolling operation without generating meandering and camber can be realized from the beginning of rolling of the rolling material head by optimally setting the rolling position.

It is a deformation | transformation characteristic identification method of the plate rolling mill of Claim 1 of this invention, Comprising: It is a figure which shows typically the algorithm of preferable 1st Embodiment with a flowchart. It is a plate rolling method of Claim 2 of this invention, Comprising: It is a figure which shows typically the algorithm by preferable 2nd Embodiment with a flowchart. It is a figure which shows typically the structure of the rolling equipment for demonstrating preferable embodiment of this invention with a side view. It is a figure which shows typically the direction of the displacement of the roll axial direction between the reinforcement roll and work roll in case roll deflection arises. Actual hot strip mill finish rolling mill by conventional method It is a figure which shows the identification result of the deformation | transformation characteristic of the rolling mill housing and rolling-down system of a 7 stand working side and a drive side. Actual hot strip mill finish rolling mill No. 1 according to the method of the present invention It is a figure which shows the identification result of the deformation | transformation characteristic of the rolling mill housing and rolling-down system of a 7 stand working side and a drive side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Four-high rolling mill 2 Housing 3a, 3b Work roll 4a, 4b Reinforcement roll 5a, 5b Work roll chock 6a, 6b Reinforcement roll chock 7 Rolling load measuring device 8 Reduction device 9a, 9b Increment work roll bending device 10a, 10b Decrease work Roll bending equipment 11 Passline height adjustment liner

Claims (2)

  The rolling mill is tightened by operating the reduction device while the roll rotation is stopped, and the rolling load measuring device provided on the working side and the drive side of the plate rolling machine with respect to a plurality of reduction position conditions. In the deformation characteristic identification method of the plate rolling mill, which simultaneously collects the output value and the measurement value of the rolling position on the working side and the driving side, and calculates the deformation characteristics of the rolling mill housing and the rolling system on each of the working side and the driving side. The plate is characterized in that the roll rotation is stopped after releasing the friction resistance between the rolls by rotating the roll for each rolling position condition, and the output value of the rolling load measuring device and the measured value of the rolling position are collected. A method for identifying deformation characteristics of a rolling mill.   Based on the deformation characteristics of the working side and driving side rolling mill housings and the reduction system identified by the deformation characteristic identifying method for a plate rolling machine according to claim 1, the working side and driving side reduction positions are set at the time of rolling. A plate rolling method characterized by calculating a value and / or a control position of a reduction position.

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