JPH07164031A - Device for estimating and controlling warp caused by rolling - Google Patents

Abstract

PURPOSE:To prevent or to reduce a warp by predicting the direction and the degree of the warp caused by rolling in a next pass and after in reverse rolling. CONSTITUTION:A sheet rolling mill equipped with a rolling load measuring device and a rolling torque measuring device for an upper and a lower rolls, a rolling load measuring device during a reverse rolling operation, and a rolling analyzing and arithmetic unit calculating at least a difference between the front surface side and the rear surface side of the deformation resistance of a rolled stock and a difference between the front surface side and the rear surface side of a coefficient of friction by analyzing the output data of a rolling torque measuring device, are provided. This device is constituted of a warp predicting, controlling arithmetic unit calculating the warp of the rolled stock, which is estimated to occur in a warp control rolling pass after a rolling pass from which a rolling data is sampled, from the measured data and the calculated result, and calculating the setting change quantity of the difference in the rotational speeds of the upper and the lower rolls to prevent a rolling warp or the setting change quantity of a pickup quantity, and a controller executing the setting change of a warp control rolling pass according to this calculated result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling process for reducing the thickness of a plate material by using at least two rolls,
The present invention relates to a device for predicting / controlling rolling warpage that occurs at the tip of a rolled material after rolling.

[0002]

2. Description of the Related Art Rolling warpage at the tip of a rolled sheet is one of the poor flatness of rolled sheets, but it is very difficult to straighten after rolling, and the rolling warpage in a region with a large sheet thickness. In some cases, the rolling equipment may be broken or a threading trouble may be caused. Therefore, research and development on the prevention technology have been made as a serious problem in the rolling operation.

As a result, the difference in deformation resistance of the rolled material due to temperature deviation or the like, the difference in friction coefficient, the difference in roll peripheral speed, and the difference in height between the entrance table and the upper end of the lower working roll of the rolling mill, It is becoming clear that the amount of pick-up, etc., will affect roll warpage.For steady and continuous warpage, the warpage can be controlled by controlling temperature deviation, pickup amount or rolling material incidence angle, upper / lower roll peripheral speed difference, etc. Techniques for preventing this are already known.

For example, Japanese Patent Application No. 3-198838 discloses a method of controlling a difference in temperature between rolled materials by water cooling and further a method of controlling warpage by a different peripheral speed rolling method or a pickup control method. A method for reducing warpage by varying the incident angle of rolled material, Japanese Patent Application No. 61-
280140 discloses a method of controlling the pickup amount and the like according to the detected warp amount.

[0005]

All of the conventional methods of warping control as described above detect the warping of the rolled material and assume that the tendency of the warping continues in subsequent rolling passes. It is a method to implement the warp control after that,
Rolling warpage is not only such a steady and continuous rolling warp, but rather, it often occurs suddenly at a certain rolling pass, and even if the conventional warpage control method is applied, the rolling warpage caused by warping is still caused. The current situation is that problems such as troubles and defective rolling shapes remain persistent.

An object of the present invention is, in multi-pass reverse rolling, based on the rolling information at the time of rolling in the previous pass, the difference between the upper and lower surfaces of the deformation resistance of the rolled material and the difference between the upper and lower surfaces of the friction coefficient that cause warpage. The present invention aims to provide a rolling warp prediction / control device capable of predicting the direction and degree of rolling warp occurring after the next pass and preventing or reducing the same by analyzing the above.

[0007]

The first gist of the present invention is as follows.
In the plate rolling machine, which has at least two upper and lower rolls for rolling a plate material a plurality of times in a reverse rolling operation to form a predetermined plate thickness, and means for independently controlling roll peripheral speeds of the upper and lower rolls, Rolling load measuring device that measures the rolling load applied to at least one of the upper and lower rolls of the machine, and a rolling torque measuring device that measures the rolling torque applied to the upper and lower rolls independently and the circumference of the upper and lower rolls. With a roll peripheral speed measuring device for measuring the speed independently, as a data analysis rolling pass any rolling pass of a plurality of rolling passes for rolling the plate material in the rolling mill, in this data analysis rolling pass Based on the measurement data of the rolling load measuring device, the rolling torque measuring device, the roll peripheral speed measuring device, at least the deformation resistance of the rolled material The difference between the surface side and the lower surface side, a rolling analysis calculation device for calculating the difference between the upper surface side and the lower surface side of the friction coefficient, and the data analysis rolling path and any rolling path after the warping control rolling path, the rolling analysis Based on the calculation result of the calculation device and the setting calculation conditions of the warpage control rolling pass, the warp curvature of the rolled material tip estimated to occur in the warpage control rolling pass, or the difference between the upper and lower surfaces of the rolling material delivery side velocity is estimated. A warp prediction / control calculation device that calculates and predicts the setting change control amount of the difference between the upper and lower roll peripheral speeds to prevent the rolling warp, and the roll based on the setting change control amount of the difference between the upper and lower roll peripheral speeds. A rolling warpage prediction / control device including a control device for setting and controlling the peripheral speed.

The second aspect of the present invention is to provide at least two upper and lower rolls for rolling a plate material in a reverse rolling operation a plurality of times to form a predetermined plate thickness, a lower rolling roll upper end and a table roller upper end. In the plate rolling machine having a means capable of setting the height difference, that is, the pickup amount independently of the roll gap, a rolling load measuring device for measuring the rolling load applied to at least one of the upper and lower roll sides of the rolling mill, , Having a rolling torque measuring device for independently measuring the rolling torque applied to the upper and lower rolls, respectively, and performing data analysis of any rolling pass of a plurality of rolling passes for rolling the plate material by the rolling mill. As, the rolling load measuring device in this data analysis rolling pass,
Based on the measurement data of the rolling torque measuring device, at least the difference between the upper surface side and the lower surface side of the deformation resistance of the rolled material, and the rolling analysis calculation device for calculating the difference between the upper surface side and the lower surface side of the friction coefficient, and the data analysis. It is estimated that any rolling pass after the rolling pass is a warp control rolling pass, and based on the calculation result of the rolling analysis calculation device and the setting calculation condition of the warp control rolling pass, the warping control rolling pass occurs. A warp prediction / control calculation device that calculates and predicts the warp curvature of the rolled material tip or the difference between the upper and lower surfaces of the rolled material delivery speed, and calculates the setting change control amount of the pickup amount to prevent the rolled warp, and the pickup. A roll warp prediction / control device including a control device for changing the setting of the pickup amount based on the control amount for changing the volume setting.

Here, the roll peripheral velocity is a roll surface velocity due to roll rotation, and is obtained by multiplying the number of roll revolutions per unit time by the outer peripheral length of the roll body. In general, since the outer peripheral length of the roll body is known from the roll diameter, the measurement and control of the roll peripheral speed is substantially equivalent to the measurement and control of the roll rotation number per unit time.

[0010]

As described above, the largest reason why the conventional method of controlling the warpage of rolling is limited to steady and continuous warpage is that there is no means for accurately predicting the direction and magnitude of the warpage for each pass of rolling. Especially.

In order to solve such a problem, in the present invention, at least the difference between the upper surface side and the lower surface side of the deformation resistance of the rolled material is analyzed by analyzing the rolling data of the previous pass for the reverse rolling operation. The difference between the upper and lower sides of the friction coefficient is calculated to accurately estimate the direction and magnitude of the rolling warp after the next pass, and to prevent this, the amount of change in the vertical difference of the roll peripheral speed or the pickup amount is picked up. We provide a rolling warpage prediction / control device that calculates and controls the amount of setting changes. In the following description, a rolling load serving as a data source for analyzing the deformation resistance of the rolled material and the difference between the upper and lower surfaces of the friction coefficient, an arbitrary rolling path to be measured such as rolling torque is referred to as a data analysis rolling path. Data analysis A rolling pass that is a target of warp prediction / control after the rolling pass will be referred to as a warpage-controlled rolling pass.

Deformation of the rolled material is considered as a mechanical phenomenon in the roll bite, and in order to consider the vertical asymmetry, it is assumed that rolling based on separate rolling conditions for the upper and lower sides is assumed to be analyzed. . In this case, the mechanical and geometrical parameters that can be a factor of rolling warpage on the roll bite exit side include the following.

Average value of deformation resistance in the plate thickness direction k _m and vertical difference k _df Vertical average value of friction coefficient μ _m and vertical difference μ _df Vertical average value of entrance side tension σ _m and vertical difference σ _df Average value of reduction amount Δh _m and vertical difference Δh _df Circumferential velocity V _T of upper roll and peripheral velocity V _{B of} lower roll

Here, the vertical difference indicated by the lower subscript df is defined as representing 1/2 of the vertical difference, and the upper roll side and the lower roll side represented by the lower subscripts T and B are defined. Each dynamical parameter and geometrical parameter is expressed by the following equation. _{k T = k m + k df} k B = k m -k df (1) μ T = μ m + μ df μ B = μ m -μ df (2) σ T = σ m + σ df σ B = σ m -σ _{df (3) Δh T = Δh} m + Δh df Δh B = Δh m -Δh df (4)

It is well known that the incident angle or pick-up amount of the rolled material has a great influence on the warpage, but these parameters cause the vertical difference of the shear strain which the rolled material receives at the entrance of the roll bite. , This becomes a factor that causes a vertical difference in deformation resistance through work hardening characteristics, or acts as a vertical difference in backward tension through the bending moment that acts on the rolled material at the roll bite inlet due to the reaction force from the table roller or its own weight,
As a result, it may cause a difference in the amount of reduction.
In this way, the effect of the incident angle of the rolled material or the pickup amount is as a mechanical parameter near the roll bite.
It can be considered to be expressed by the above k _df , σ _df , and Δh _df , and when mechanically analyzing the deformation of the rolled material in the vicinity of the roll bite, the above items 1 to 4 are independent parameters.

The present invention is directed to the warp of the rolled material at the tip, and the tension on the delivery side can be always regarded as zero, so it is excluded from the above independent variables. However, when the warpage-controlled rolling pass is the rolling pass immediately after the data analysis rolling pass, the warped control rolling pass naturally considers the rolled material tip. Should be analyzed. In this case, the output side tension becomes an independent variable instead of the input side tension, and the input side tension can be regarded as almost zero. Therefore, in the following description, the rolled material front end, that is, the case where the entrance side tension is an unknown parameter is targeted, but when the rolled material rear end is considered, that is, when the exit side tension is an unknown parameter , Σ _m , and σ _df can be read as the tension on the outlet side, and the following discussion can be applied in the same manner.

Among the above-mentioned parameters (1) to (8), those which can be directly measured are the average reduction amount Δh _m and V of
_T and V _B. To measure the average rolling reduction Delta] h _m may be measured thickness at entrance side and exit side thickness of the rolling mill, the roll peripheral speed V _T, V _B can be determined by measuring the roll rotation speed directly. In order to measure Δh _m, the gauge plate type may be used to calculate the inlet side plate thickness and the outlet side plate thickness from the rolling load measurement, but in the case of a rolling machine of the upper and lower independent drive system, the vertical roll peripheral velocity V _T , It is preferable to measure V _B independently of each other. Further, in the case of performing the warp control by the difference between the upper and lower roll peripheral speeds as in the first aspect of the present invention, highly accurate measurement is required. It is an essential requirement to equip a device that measures the upper and lower roll peripheral speeds independently.

For these, the remaining parameters k _m ,
k _df , μ _m , μ _df , σ _m , σ _df , and Δh _df are essentially difficult parameters to measure directly. The rolling warpage prediction / control device of the present invention identifies these mechanical parameters from the rolling data of the data analysis rolling pass, and predicts the rolled material tip warpage in the warpage control rolling pass based on the identification result, The setting change amount of the upper and lower roll peripheral speed difference or the setting change amount of the pickup amount for prevention is calculated, and the warp control is performed based on this.

By the way, when analyzing the upper roll side and the lower roll side as independent rolling phenomena, in order to calculate the rolling load and the rolling torque, the inlet side plate thickness H _T , the outlet side plate thickness h _T , and the lower side plate thickness h _{T are} calculated. An inlet side plate thickness H _B on the roll side and an outlet side plate thickness h _B are required. These are the outlet plate thickness h and Δ
The method of obtaining from h _m and Δh _df is, for example, dividing the output side plate thickness into upper and lower halves and dividing the input side plate thickness by horizontally extending the center line of the output side plate thickness, or the output side plate thickness Various methods are conceivable, such as a method of determining based on the contact arc length ratio of H., but in any case, H _T , h _T , H _B , and h _B are known quantities h and Δh _m are not shown. , Unknown amount Δh _df
Is given uniquely as a function of. That is, the following equation is obtained.

[0020]

[Equation 1]

In the case of single-stand rolling, the total tension on the entry side must be zero, and even in the case of tandem rolling, the total tension at the moment when the tip of the rolled material is bitten is almost zero. The following relational expression, in which the total tension on the side is zero, must hold. H _T σ _T + H _B σ _B = 0 When formula (3) is substituted into the above formula, the following formula is obtained.

[Equation 2]

[Equation 3] The unknown σ _m can be immediately eliminated by using the equation (10).

Now, the remaining unknown parameters are k _m ,
k _df , μ _m , μ _df , σ _df , Δh _df , of which k
_m and μ _m are vertical average values and have essentially no effect on rolling warpage, which is a vertical asymmetric phenomenon, and four parameters k _df , μ _df , which represent the difference between the upper roll side and the lower roll side,
σ _df and Δh _df are more essential parameters. Further, among these four parameters, the important parameters as the cause of warpage are the vertical difference k _df of the deformation resistance and the vertical difference μ _df of the friction coefficient, and the vertical difference σ _df of the backward tension and the vertical difference of the reduction amount. Δh _df is the vertical difference that occurs due to the mechanical balance due to k _df and μ _df , and rather results. Therefore, in order to predict rolling warpage, identifying k _df and μ _df is an essential requirement. Further, when the reverse rolling is taken into consideration as in the present invention, the vertical difference k _df of the deformation resistance depends on the homogeneity including the temperature of the rolled material, and therefore the tendency continues after the next pass. In addition, since the difference in vertical coefficient of friction μ _df is governed by the surface properties of the work roll and the properties near the surface including the temperature of the rolled material, a certain tendency continues after the next pass. It has the property of being Therefore, by analyzing these parameters from the rolling data of the data analysis rolling pass and using them for the rolling warpage prediction of the warping control rolling pass after the data analysis rolling pass, accurate warpage prediction / control becomes possible.

FIG. 1 shows the structure of the rolling warp prediction / control apparatus according to the first aspect of the present invention and its operation. First, a plate rolling machine that has a rolling load measuring device, a vertical rolling torque measuring device, and an upper and lower roll peripheral speed measuring device, and can control the upper and lower roll peripheral speeds independently. , Collect upper and lower roll peripheral speed data.

Next, the rolling analysis operation device analyzes the above rolling data to calculate at least the upper and lower surface difference k _df of the deformation resistance of the rolled material and the upper and lower surface difference μ _df of the friction coefficient. For this method, for example, a method of calculating k _df and μ _df by solving simultaneous rolling model formulas used for setting calculation of a rolling mill in a process computer, and a collection of papers of the spring meeting of the Japan Plastic Processing Society in 1986. Calculations in various cases are preliminarily executed using an off-line analytical model disclosed in “Analysis of Asymmetric Rolling by Rigid-Plastic Finite Element Method” by Yamada et al. On pages 235 to 238. The relationship between rolling load, vertical rolling torque, vertical roll peripheral speed, upper and lower surface difference of rolling material deformation resistance, and upper and lower surface difference of friction coefficient is linearly approximated and calculated as an influence coefficient matrix, which is stored in the process computer. It is possible to adopt a method of calculating k _df and μ _df in the process computer using the influence coefficient matrix.

Further, in the warp prediction / control calculation device, the warp control rolling is performed based on the calculation results of k _df and μ _df by the rolling analysis calculation device and the data calculation analysis setting conditions for the warp control rolling pass after the rolling pass. The warp curvature κ of the rolled material estimated to occur in the pass or the upper and lower surface difference W of the rolled material delivery side speed is calculated and predicted, and the setting change control amount δV of the difference between the upper and lower roll peripheral speeds for preventing the rolling warp. Calculate _df . In this method, too, the rolling model formulas used for setting calculation of the rolling mill are solved simultaneously in the process computer, and the influence coefficient matrix is calculated in advance by using an offline analysis model. Then, it is possible to adopt a method of calculating in the process computer.

Finally, by the roll peripheral speed control device,
Setting change control amount of upper and lower roll peripheral speed difference calculated above δ
By controlling the peripheral speed of the upper and lower rolls of the plate rolling machine based on V _df , it becomes possible to prevent the occurrence of rolling warpage.

As a means for independently controlling the peripheral speeds of the upper and lower rolls, a well-known twin drive system for a reverse rolling machine or the like can be adopted.

FIG. 2 shows the configuration and operation of the rolling warpage prediction / control device of the second invention of the present invention. First, a rolling mill having a rolling load measuring device and a vertical rolling torque measuring device, and a plate rolling machine having means for setting the pick-up amount independently of the roll gap, is used for data analysis. Collect. At this time, in the case of a plate rolling mill in which the upper and lower roll peripheral speeds can be independently controlled, it is preferable to provide a device for independently measuring the upper and lower roll peripheral speeds and collect data of the upper and lower roll peripheral speed differences. However, the second invention of the present invention is also applicable to a plate rolling machine having a structure in which the drive shafts of the upper and lower rolls are mechanically coupled by a pinion gear and the upper and lower roll rotation speeds are always the same, In this case, it is not necessary to measure the roll peripheral speed difference.

Next, the rolling analysis calculation device analyzes the rolling data to calculate at least the upper and lower surface difference k _df of the deformation resistance of the rolled material and the upper and lower surface difference μ _df of the friction coefficient. This method includes, for example, a method in which k _df and μ _df are calculated by solving simultaneous rolling model formulas used for setting calculation of the rolling mill in a process computer, and the 1986 Spring Meeting of the Japan Plastic Processing Society. Calculations in various cases are preliminarily executed using an off-line analytical model disclosed in “Analysis of Asymmetric Rolling by Rigid-Plastic Finite Element Method” by Yamada et al. On pages 235 to 238. The relationship between rolling load, vertical rolling torque, vertical roll peripheral speed, upper and lower surface difference of rolling material deformation resistance, and upper and lower surface difference of friction coefficient is linearly approximated and calculated as an influence coefficient matrix, which is stored in the process computer. It is possible to adopt a method of calculating k _df and μ _df in the process computer using the influence coefficient matrix.

Further, in the warp prediction / control arithmetic unit, the warp control rolling is performed based on the calculation results of k _df and μ _df by the rolling analysis arithmetic unit and the data analysis setting calculation conditions for the warp control rolling pass after the rolling pass. A warp curvature κ of the rolled material estimated to occur in the pass or an upper / lower surface difference W of the rolled material delivery side speed is calculated and predicted, and a setting change control amount Δy of the pickup amount for preventing the warp of the rolled material is calculated. . In this method, too, the rolling model formulas used for setting calculation of the rolling mill are solved simultaneously in the process computer, and the influence coefficient matrix is calculated in advance by using an offline analysis model. Then, it is possible to adopt a method of calculating in the process computer.

Finally, the pickup amount setting control device calculates the above-mentioned pickup amount setting change control amount Δ.
By performing the setting change of the pickup amount based on y, it becomes possible to prevent the occurrence of rolling warp.

As a means for setting the pickup amount independently of the roll gap, there is a method of providing a roll down device for each of the upper and lower roll systems. For example, a well-known hydraulic or electric roll down system is provided for each of the upper and lower roll systems. With a device
The upper and lower roll systems may be independently rolled down.

The method of calculating the difference between the upper and lower surfaces of the deformation resistance of the rolled material and the difference between the upper and lower surfaces of the friction coefficient by analyzing the rolling data such as rolling load and rolling torque has been described above. The upper and lower surface temperature measuring device is provided, and the upper and lower surface difference k _df of the rolling resistance of the rolled material is obtained from the deformation resistance equation based on the upper and lower surface temperature measurement results, and the unknown value is reduced. Top and bottom difference μ
A method of obtaining _df and predicting / controlling the warpage of the warpage control rolling pass is also a preferable method in terms of shortening the operation time of the warpage prediction / control and increasing the accuracy.

Further, the warpage control rolling pass is preferably a rolling pass immediately after the data analysis rolling pass, but when the rolling analysis calculation device and the warp prediction / control calculation device have a long calculation time and cannot control the next pass. The data analysis rolling pass may be used as a warp control rolling pass one after another.

Furthermore, not only analysis and control for the same rolled material but also warpage control of the first rolling pass of the next rolled material
It is also a preferable application example of the present invention to refer to the vertical difference of the deformation resistance and the vertical difference of the friction coefficient analyzed from the rolling results of the previous material.

[0036]

【Example】

Example 1 A rolling load measuring device, an upper and lower roll rolling torque measuring device, and an upper and lower roll peripheral speed measuring device are provided, and the upper and lower roll peripheral speeds can be independently controlled, for example, a twin drive type,
A preferred embodiment for performing reverse rolling of a plate material using a plate rolling machine will be described. First, the first pass rolling as data analysis rolling pass, the rolling load measurement value P during rolling the rolled material near a rear end in the first pass, the rolling torque measurement value G _T, G
_B , and roll peripheral velocities V _T and V _B are measured.

From the condition that these measured values and the calculated values by the rolling load calculation formula and the rolling torque calculation formula used for execution by the process computer match,
The following equation is obtained.

[Equation 4]

Known quantities such as the roll diameter and the average strip thickness reduction Δh _m are omitted from the independent variables in the parentheses on the right side of the equations (11) to (14), and the strip thicknesses H _T and H _{B of} the inlet side are also omitted. The outgoing plate thicknesses h _T and h _B are expressed as a function of Δh _df by substituting the equations (5) to (8). Thus, equation (11) to (14), by considering the equation (1) to (3), the unknown variable _{k m, k df, μ m} , μ df, σ df,
It is a system of equations related to Δh _df . Note that σ _m is
Since it is considered that it has already been erased by the formula (10), in this example, since rolling data in the vicinity of the trailing edge of the rolled material is collected, σ _m and σ _df are not the inlet tension but the outlet tension. It shall represent the upper and lower average values and the upper and lower differences. In this case, the entrance tension can be regarded as zero.

As a system of equations that can be used, equation (11)
In addition to (14), there is a matching condition expression for the material on the output side. That is, here, since the data at the time of rolling the trailing edge of the rolled material is analyzed, the material on the delivery side is sufficiently long, and the material speed on the delivery side is equal on the upper and lower surfaces due to the influence of its own weight. This condition is expressed by the following equation when the advanced rates on the upper roll side and the lower roll side are f _T and f _B , respectively. (1 + f _T ) _VT = (1 + f _B ) V _B (15) Here, the roll peripheral speeds V _T and V _B are known from the output from the roll peripheral speed measuring device, and f _T and f _B are rolling theory. From the above unknowns k _m , k _df , μ _m , μ _df , σ _df , Δh _df, and known functions of known rolling conditions,
Expression (15) can be expressed as the following expression using the known function F. _{F (k m, k df,} μ m, μ df, σ m, σ df, Δh df; V T, V B) = 0 (16)

The above equations (11) to (14) and equation (1)
6) is a system of 5 equations that can be used. On the other hand, there are currently six unknowns to be obtained. However, due to the fact that the rolling warp is based on the vertical asymmetric deformation behavior, these remaining six unknown variables k _m , k _df , μ _m , μ
_{Of df} , σ _df , and Δh _df, the four that are essentially important for predicting the roll warpage are k _df , μ _df , σ _df , and Δh _df , which indicate the difference between the upper roll side and the lower roll side. There, the estimation accuracy of the k _m, mu _m that represents the vertical average value for the warping prediction, it is clear that not critical. In particular, with respect to the average value mu _m of the coefficient of friction, because the element is small to vary the temperature dependency less each rolling pass, for example, rolling load and rolling values are used to set up calculation function or before rolling path, Even if the value calculated back from the torque is used, the warp prediction / control accuracy is not substantially deteriorated. Therefore, if such a value is used for μ _m , the unknowns are k _m , k
There are five _df , μ _df , σ _df , and Δh _df . Therefore, the solution can be obtained by solving the above-mentioned five nonlinear equation systems.

For solving this nonlinear equation, for example, Ne
Iterative calculation methods such as the Wton-Raphson method may be used. K _m As described _{above, k df, μ df, σ} df, Δ
It is possible to obtain all the values of h _df .

In the present embodiment, the rolling pass next to the data analysis rolling pass which is the subject of the above analysis is the warpage control rolling pass. In this case, in the warp control rolling pass, the rolled material rear end portion in the data analysis rolling pass becomes the rolled material tip, and the warp prediction during the rolling material tip rolling of the warp control rolling pass and the roll peripheral speed for preventing it Calculation of the operation amount of the vertical difference is performed by the warp prediction / control arithmetic unit.

Warp Control There are several methods for estimating the vertical difference of deformation resistance and the vertical difference of friction coefficient used for warp prediction / control of the rolling pass by referring to the value of the data analysis rolling pass just analyzed. However, in this embodiment, the following method is adopted as the simplest method that can be executed online.

Ratio of vertical difference of deformation resistance and average value k _df /
k _m, and a ratio of height difference between the average value of the friction coefficient μ _df / μ _m
Of the warpage control rolling pass, the mean value of deformation resistance k _{m of} the warpage control rolling pass and the mean value of friction coefficient μ _m are calculated from a set calculation model, and data analysis k _df / k _{m of the} rolling pass and From the value of μ _df / μ _m , k _df , μ _df
Ask for. By this procedure, the only unknown parameters regarding the warpage-controlled rolling pass are σ _df and Δh _df . In addition,
In the case of a warpage-controlled rolling pass, the tip side threading is taken into consideration, so the exit side tension can be regarded as zero, and the upper and lower average values σ _m and upper and lower differences σ _{df of} the entrance side tension are unknown. σ
_m is immediately erased under the condition that the total tension on the exit side is zero.

When studying the warpage control rolling pass, the actual values of rolling load and rolling torque cannot be used, but since there are only two unknown parameters, σ _df and Δh _df , the solution is obtained by solving the following equation. Can be asked.

Conditional expression that the upper and lower rolling loads are equal

[Equation 5] And the conditional expression that the material speed on the inlet side is equal on the upper and lower surfaces (h _T / H _T ) (1 + f _T ) _VT = (h _B / H _B ) (1 + f _B ) V _B (18) V _T and V _B are known from the output from the roll circumferential velocity measuring device, and f _T and f _B are the unknowns σ _df and Δh _df and known k _m and k _df from the rolling theory.
It can be expressed as a known function of μ _m , μ _{df and} other rolling conditions.
By solving the above equations (17) and (18) as a nonlinear equation relating to σ _df and Δh _df , σ _df and Δh _df are obtained. If these are obtained, along with the already known amounts of k _m , k _df , μ _m , μ _df , σ _m , Δh _m , V _T , and V _B , mechanical and geometric factors that can cause rolling warp. All the physical parameters have been sought.

Roll bite exit velocity v _T of the rolled material on the upper roll side, Roll bite exit velocity v _T of the rolled material on the lower roll side
_B is calculated by the following equation, where the advanced rates are f _T and f _B , respectively. v _T = V _T (1 + f _T ), v _B = V _B (1 + f _B ) (19)

When the curvature of curvature is κ, κ can be calculated from v _T and v _B by the following equation due to the geometrical relation.
Here, f _T and f _B can be calculated from the above parameters and known rolling conditions by the advanced ratio calculation formula.

[Equation 6] Note that h is the exit plate thickness, and the warp curvature κ is positive in the upward warp direction.

The setting change control amount of the upper and lower roll peripheral speed difference for preventing the warpage predicted by the equation (20) is the upper and lower rolled material speed difference W, that is, W = v _T −v _B = V _T (1 + f _T ) determined -V _B (1 + f _B) to (21) to zero.

When half of the setting change control amount of the upper and lower roll peripheral speed difference is set to δV _df = δ (V _T −V _B ) / 2 (22), the upper and lower roll peripheral speeds are respectively V _T + δV
_{Since df} and V _B −δV _df , the equation (22) becomes the following equation. W = (V _T + δV _df ) (1 + f _T ) − (V _B −δV _df ) (1 + f _B ) (23)

When the initial value of W when δV _df = 0 is W ₀ , the value of δV _df at which W = 0 is obtained by dW /
Calculate d (δV _df ) and first use the following equation as the first-order approximate solution. δV _df = −W ₀ / {dW / d (δV _df )} (24) If a more accurate value of δV _df is required, V _T ,
It suffices to update the value of V _B with the calculation result of equation (24) and repeat the above procedure.

In the calculation of dW / d (δV _df ), it must be taken into consideration that f _T and f _B are functions of δV _df to be exact, but approximately this is ignored.

[Equation 7] There is also a method to substitute with.

The occurrence of rolling warp can be prevented by changing the setting of the roll peripheral speed of the warp control rolling pass based on the calculation result of the equation (24).

Further, when the rolling of the warp control rolling pass is started, the warp control rolling pass is regarded as the next data analysis rolling pass to collect rolling data, and the next rolling pass is also used as the warpage controlling rolling pass. By repeating the above procedure, it becomes possible to control the warpage of all rolling passes.

When the above calculation is not in time for the next pass of the data analysis rolling pass, the rolling data at the tip of the rolled material in the data analysis rolling pass is analyzed and the subsequent passes are used as the warpage control rolling pass to similarly predict the warpage.・ Control should be carried out. In this case, the rolling passes in between are regarded as data analysis rolling passes for making the subsequent passes into warpage control rolling passes, and are subjected to rolling data collection / analysis.

Further, the method of calculating the temperature by disposing the upper and lower surface thermometer of the rolled material and calculating the upper and lower surface difference k _df of the deformation resistance by the deformation resistance calculation formula used in the setting calculation also requires a long calculation time. It is effective in saving and improving the calculation accuracy.

Example 2 Sheet rolling having a rolling load measuring device and an upper and lower roll rolling torque measuring device, and means for setting the pickup amount independently of the roll gap, for example, plate rolling having hydraulic rolling down devices for the upper and lower roll systems, respectively. A preferred embodiment in the case of performing reverse rolling of a plate material using a machine will be described. As in Example 1, the first pass rolling as data analysis rolling pass, the rolling load measurement value P during rolling the rolled material near a rear end in the first pass, the rolling torque measurement value G _T, measuring the G _B . In the plate rolling mill of this embodiment, the drive shafts of the upper and lower rolls are connected by pinion gears, and the roll rotation speed is always the same in the upper and lower directions.

When the upper and lower surface difference k _df of the deformation resistance of the rolled material and the upper and lower surface difference μ _df of the friction coefficient of the rolled material are calculated from the measured rolling load value and the measured rolling torque value, as in Example 1, based on the rolling theory. In this embodiment, a method of using the influence coefficient matrix obtained in advance is adopted instead of the method of solving the setting calculation formula in the process computer.

For example, the offline method as disclosed in the paper "Analysis of Asymmetric Rolling by the Rigid-Plastic Finite Element Method" by Yamada et al. Using the analytical model, it is possible to calculate the influence coefficient matrix M (3 × 3 matrix) defined by the following equation for each rolling condition.

[0060]

[Equation 8] And a, P: rolling load, l _d: Contact arc length (vertical average), G _df: rolling torque height difference, G _m: rolling torque vertical average value, k _df: deformation resistance height difference, k _m: deformation resistance Vertical average value, μ _df : friction coefficient vertical difference, μ _m : friction coefficient vertical average value, V _df : roll peripheral speed vertical difference, V _m : roll peripheral speed vertical average value, κ: warp curvature.

The value of each component of the influence coefficient matrix M changes depending on the rolling conditions.
If a table is created and stored in the process computer, the value of M corresponding to the rolling condition can be called in the memory in the setting calculation before the start of rolling for each rolling condition.

After the above-mentioned preparation, the standardized deformation resistance difference k ′ _df and friction coefficient upper / lower are standardized from the rolling load measurement value and the rolling torque measurement value at the time of rolling the rear end of the rolled material. The difference μ ′ _df is obtained as follows.

Taking into consideration the roll peripheral speed difference V ′ _df = 0 and extracting the equations relating to P ′ and G ′ _df from the equation (25), the following equation is obtained.

[Equation 9]

[0064] Thus, P from rolling load and rolling torque measurements ', G' because _df is obtained using the following equation obtained by solving equation (25) in the opposite k _'df, mu' Request _df.

[Equation 10]

In the present embodiment, the rolling pass next to the data analysis rolling pass, which is the subject of the above analysis, is the warpage control rolling pass. In this case, in the warp control rolling pass, the trailing end of the rolled material in the data analysis rolling pass becomes the rolled material tip, and the warp prediction at the time of rolling of the rolled material tip in the warp controlled rolling pass and the setting of the pickup amount for preventing it are set. The change control amount is implemented by the warp prediction / control calculation device.

Data analysis obtained by the above procedure It is assumed that the values of k ′ _df and μ ′ _{df in} the rolling pass are the same in the warping control rolling pass, and this is expressed together with V ′ _df = 0 in the equation for the warping control rolling pass. By substituting in (25),
Warp control Warp curvature κ ₀ estimated to occur in rolling pass
Can be calculated and predicted.

Next, the set change control amount Δy of the pickup amount for preventing the warp during the rolling of the rolled material tip in the warp control rolling pass is calculated. As a preparation for this, for example, the relationship between the pickup amount and the warp curvature is represented by the following equation with an influence coefficient K by off-line calculation using the method disclosed in the above-mentioned paper by Yamada et al. Δκ = KΔy (29)

The influence coefficient K varies depending on the rolling conditions such as the plate thickness, the rolling reduction, the deformation resistance of the rolled material, etc., but like the matrix M described above, it is modeled or tabulated to be processed by a process computer. If it is stored in the memory, the value of K corresponding to the rolling condition can be called in the memory in the setting calculation before the rolling start for each rolling condition. From equation (29), the setting change control amount Δy of the pickup amount for reducing the warp curvature κ ₀ predicted in the next rolling pass to zero is calculated by the following equation. Δy = −κ ₀ / K (30) The tip warp can be prevented by changing the setting of the pickup amount of the warp control rolling pass based on the calculation result of the equation (30).

It should be _noted that a method of calculating the temperature by providing an upper and lower surface thermometer for the rolled material and calculating the upper and lower surface difference k _df of the deformation resistance by the deformation resistance calculation formula used in the setting calculation also saves calculation time. However, it is effective in improving the calculation accuracy.

[0070]

EFFECTS OF THE INVENTION By adopting the rolling warpage prediction / control device of the present invention, it becomes possible to prevent the rolling warpage that tends to occur at the tip of the rolled material, and to avoid troubles in the rolling operation. The flatness of the rolled material can be greatly improved, and a great effect can be obtained in reducing the rolling cost and improving the quality of the rolled material.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a warp prediction / control device according to a first invention of the present invention.

FIG. 2 is a diagram showing a configuration of a warp prediction / control device according to a second invention of the present invention.

Claims (2)

[Claims] 1. A plate rolling device having at least two upper and lower rolls for rolling a plate material a plurality of times in a reverse rolling operation to form a predetermined plate thickness, and means capable of independently controlling roll peripheral speeds of the upper and lower rolls. In a rolling mill, a rolling load measuring device for measuring a rolling load applied to at least one of upper and lower rolls of the rolling mill, and a rolling torque measuring device for independently measuring a rolling torque applied to the upper and lower rolls. And a roll peripheral speed measuring device for independently measuring the peripheral speed of each of the upper and lower rolls, and any one of a plurality of rolling paths for rolling the plate material by the rolling machine as a data analysis rolling path, Data analysis Based on the measurement data of the rolling load measuring device, the rolling torque measuring device, and the roll peripheral speed measuring device in the rolling pass, at least the rolled material The difference between the upper surface side and the lower surface side of the deformation resistance of, and the rolling analysis calculation device for calculating the difference between the upper surface side and the lower surface side of the friction coefficient, and the data analysis rolling path and any rolling path after the warping control rolling path. , Based on the calculation result of the rolling analysis calculation device and the setting calculation condition of the warp control rolling pass, the warp curvature of the rolled material tip estimated to occur in the warp controlled rolling pass, or the rolled material outgoing speed A warp prediction / control calculation device that calculates and predicts the difference between the upper and lower surfaces and calculates the setting change control amount of the difference between the upper and lower roll peripheral speeds for preventing the above-described rolling warp, and the setting change control amount of the difference between the upper and lower roll peripheral speeds. Warp prediction / control device comprising a control device for setting and controlling the roll peripheral speed based on the above. 2. A roll gap is defined by a height difference between at least two upper and lower rolls that roll a plate material a plurality of times in a reverse rolling operation to form a predetermined plate thickness and a lower rolling roll upper end and a table roller upper end. In a plate rolling mill having means that can be set independently of each other, a rolling load measuring device for measuring a rolling load applied to at least one of the upper and lower roll sides of the rolling mill, and a rolling torque applied to the upper and lower rolls. The upper and lower rolls each have a rolling torque measuring device that measures independently, and any one of a plurality of rolling passes for rolling a plate material by the rolling mill is used as a data analysis rolling pass, and in the data analysis rolling pass, Based on the measurement data of the rolling load measuring device and the rolling torque measuring device, at least the difference between the upper surface side and the lower surface side of the deformation resistance of the rolled material and the friction A rolling analysis calculation device that calculates the difference between the upper surface side and the lower surface side of the friction coefficient, and any rolling path after the data analysis rolling path as a warp control rolling path, and the calculation result of the rolling analysis calculation device and the warp. Based on the setting calculation conditions of the controlled rolling pass, the warp curvature of the rolled material tip that is estimated to occur in the warped controlled rolling pass or the difference between the upper and lower surfaces of the rolled material delivery speed is calculated and predicted to prevent the rolling warpage. A warp prediction / control calculation device that calculates a setting change control amount of the pickup amount for controlling the rolling warp prediction / control device including a control device that executes the setting change of the pickup amount based on the pickup amount setting change control amount. Control device.