A method and system for controlling the shape of a cold-rolled sheet

Abstract

The present application relates to the field of cold-rolled sheet shape control, and relates to a cold-rolled sheet rolling shape control method and system. The present application measures the thickness of each monitoring point in the width direction of the incoming sheet at the entrance of the rolling mill in real time, analyzes the fluctuating thickness of each monitoring point of the incoming sheet to identify local fluctuation points, determines the temperature compensation amount of each monitoring point of the roll in combination with the distribution position, and analyzes the pre-output cooling flow of each cooling nozzle of the segmented cooling device based on the temperature compensation amount. The transverse tension distribution data of the cold-rolled sheet after rolling at the current rolling mill outlet is measured, each tension component of each monitoring point tension value is extracted, the type of sheet shape is determined through the proportion analysis of each tension component, and the roll to be adjusted of the rolling mill is determined. The abnormal monitoring point is determined by analyzing the residual tension component array, the correction amount of the corresponding cooling nozzle is calculated, and the final cooling flow is determined in combination with the pre-output cooling flow of each cooling nozzle. The present application improves the pertinence of sheet shape control and the sheet shape quality.

Description

Technical Field

[0001] This invention relates to the field of cold-rolled sheet shape control, and specifically to a method and system for controlling the shape of cold-rolled sheets. Background Technology

[0002] Cold-rolled sheet is a core raw material for many industries such as metallurgy, machinery manufacturing, automobiles, and home appliances. Sheet shape is a key quality indicator. Single-sided waviness, medium waviness, double-sided waviness, and local warping directly affect the adaptability of subsequent processing steps, the structural accuracy of finished parts, and their performance. Therefore, precise control of sheet shape during the rolling process of cold-rolled sheet is one of the core technical aspects of cold rolling production.

[0003] Existing technologies, such as Chinese Patent Publication No. CN105499279A, disclose a feedforward control method for cold-rolled strip shape. This method involves configuring a strip shape meter at the cold rolling mill inlet, or simultaneously at the cold rolling mill inlet and outlet, to detect the strip shape at the cold rolling mill in real time. The control objectives are stable rolling process and good strip shape at the outlet. Based on the changes in strip shape at the mill inlet, the mill shape adjustment mechanism is adjusted in a feedforward manner to improve the shape control accuracy.

[0004] Chinese Patent Publication No. CN112872047B discloses a method for controlling the shape of a cold rolling mill. This method calculates the initial amount of bending roll adjustment and cooling adjustment based on the shape deviation; then calculates the final amount of bending roll adjustment, cooling adjustment, and rolling force control; and finally adjusts the shape based on the final amount of bending roll adjustment, cooling adjustment, and rolling force control, thereby improving the quality of shape adjustment.

[0005] However, the existing technology has the following problems: 1. The existing technology adjusts the shape of the rolling mill by detecting the strip shape at the entrance of the cold rolling mill and controlling the crown adjustment mechanism. However, it does not take into account the fact that the local thickness fluctuation of the initial incoming plate cannot be accurately adjusted by the crown adjustment mechanism, which has limitations in improving the stability of the rolling process and ensuring the quality of the product shape.

[0006] 2. Existing technologies mostly control cooling by calculating the overall cooling adjustment amount, without considering the analysis of residual components of the transverse tension of the thin plate to pinpoint abnormal plate shape points, or the use of feedforward to make targeted corrections to the flow rate of segmented cooling nozzles. As a result, it is difficult to effectively solve local abnormal plate shape that occurs during rolling through cooling regulation, leading to insufficient precision and accuracy in plate shape control. Summary of the Invention

[0007] This invention aims to address the shortcomings of existing technologies by providing a method and system for controlling the shape of cold-rolled thin plates. It solves the problems of existing technologies lacking targeted control over local thickness fluctuations in incoming plates and precise feedback correction of cooling flow after rolling, thereby improving the accuracy of shape control and eliminating local anomalies.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: On one hand: a method for controlling the shape of cold-rolled thin plates, comprising: measuring the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, and analyzing the fluctuating thickness of each monitoring point of the incoming plate to identify local fluctuation points.

[0009] The temperature compensation amount of each monitoring point of the roll is determined based on the fluctuation thickness and distribution location of each local fluctuation point, and the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device is analyzed based on the temperature compensation amount.

[0010] The transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit is measured, and the tension components of each monitoring point are extracted. The sheet shape type is determined by analyzing the proportion of each tension component, and the mill roll to be adjusted is determined based on the sheet shape type.

[0011] Anomaly monitoring points are obtained by analyzing outliers in the residual tension component array. The correction amount of the corresponding cooling nozzle is calculated based on the residual tension component of the anomaly monitoring point. The final cooling flow rate is determined by combining the pre-output cooling flow rate of each cooling nozzle.

[0012] On the other hand, a cold-rolled thin plate rolling shape control system includes: a fluctuation point identification module, a temperature compensation module, a rolling feedback module, a cooling flow correction module, and a strategy execution module. The modules are connected as follows: the fluctuation point identification module is connected to the temperature compensation module; the rolling feedback module is connected to both the temperature compensation module and the cooling flow correction module; and the strategy execution module is connected to the cooling flow correction module.

[0013] The fluctuation point identification module measures the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, and analyzes the fluctuation thickness of each monitoring point of the incoming plate to identify local fluctuation points.

[0014] The temperature compensation module determines the temperature compensation amount for each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point, and analyzes the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device based on the temperature compensation amount.

[0015] The rolling feedback module measures the transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit, extracts the tension components of each monitoring point, determines the sheet shape type by analyzing the proportion of each tension component, and determines the mill rolls to be adjusted based on the sheet shape type.

[0016] The cooling flow correction module analyzes outliers in the residual tension component array to obtain abnormal monitoring points, calculates the correction amount of the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring points, and determines the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention measures the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, analyzes the fluctuation thickness of each monitoring point of the incoming plate to identify local fluctuation points, and realizes the early capture of the interference factor of local thickness fluctuation of the incoming material, thereby improving the pertinence of plate shape control.

[0018] (2) The present invention determines the temperature compensation amount of each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point, and analyzes the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device based on the temperature compensation amount, avoiding temperature compensation deviation caused by ignoring heat conduction, so that the roll temperature adjustment can accurately correspond to the abnormal area of ​​incoming material thickness, and improve the accuracy of adjustment.

[0019] (3) This invention measures the transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit, extracts the tension components of each monitoring point, determines the sheet shape type by analyzing the proportion of each tension component, determines the mill roll to be adjusted based on the sheet shape type, and transforms the sheet shape determination into a quantifiable data analysis process, avoiding human judgment errors and ensuring the stability of the rolling process.

[0020] (4) This invention obtains abnormal monitoring points by analyzing the abnormal values ​​in the residual tension component array, calculates the correction amount of the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring point, and determines the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle, thereby achieving accurate capture of local small plate shape defects, completing the local abnormal correction after main plate shape adjustment, and improving plate shape quality. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the method steps of the present invention;

[0023] Figure 2 This is a schematic diagram illustrating the specific steps involved in obtaining the temperature compensation amount according to the present invention.

[0024] Figure 3 This is a schematic diagram of the specific steps for obtaining the correction amount of the cooling nozzle according to the present invention.

[0025] Figure 4 This is a schematic diagram of the system module connections of the present invention. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0027] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0028] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0029] Please see Figure 1 As shown, the present invention provides a method for controlling the shape of cold-rolled thin plates, including: S1, identifying local fluctuation points based on the thickness of each monitoring point in the width direction of the incoming plate.

[0030] Considering that local thickness fluctuations in the width direction of the incoming plate are a major cause of abnormal rolling shape, and that the adjustment mechanisms of the rolls, such as bending and tilting, can only effectively compensate for the parabolic thickness distribution characteristics of overall tilt, thick in the middle and thin at both ends, or thin in the middle and thick at both ends, it is possible to identify the overall thickness distribution characteristics and local fluctuation points by solving the first and second degree functions. If only the overall trend of the thickness distribution is considered and local fluctuations are ignored, the subsequent roll adjustment and cooling control will lack specificity and will not be able to accurately solve the local abnormal plate shape.

[0031] Furthermore, considering that the incoming material inspection data should provide accurate quantitative basis for subsequent segmented temperature compensation and cooling flow rate adjustment, the location of the monitoring points should be matched with the segmented location of subsequent cooling adjustment.

[0032] Based on this, the specific implementation steps of S1 are as follows: S11, measure the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, and analyze the lateral fluctuation thickness distribution characteristics of the incoming plate to identify local fluctuation points.

[0033] In a specific embodiment of the present invention, the method for analyzing local fluctuation points includes: S111, taking the projection points of each cooling nozzle of the segmented cooling device in the width area of ​​the incoming material plate as monitoring points in the width direction of the incoming material plate.

[0034] S112. Measure the thickness of each monitoring point using a thickness gauge. Take the distance of each monitoring point from the side of the incoming material plate as the independent variable and the thickness of the corresponding monitoring point as the dependent variable. Determine the optimal fitting function by substituting it into a preset polynomial function model.

[0035] Specifically, two monitoring points are randomly selected from each monitoring point. The distance from the side of the incoming material plate is used as the independent variable, and the thickness of the corresponding monitoring point is used as the dependent variable. These are then substituted into a first-order polynomial model to solve for a temporary function. The remaining independent variables are substituted into the temporary function, and points where the result equals the corresponding dependent variable are recorded as coincidence points. The number of coincidence points for each temporary function is counted, and the temporary function with the most coincidence points is selected as the fitted first-order function. Similarly, three monitoring points are randomly selected from each monitoring point. The distance from the side of the incoming material plate is used as the independent variable, and the thickness of the corresponding monitoring point is used as the dependent variable. These are then substituted into a second-order polynomial model to solve for a temporary function. The fitted second-order function is obtained following the same steps as for the first-order function. The number of coincidence points between the two functions is compared, and the function with the most coincidence points is selected as the preferred fitted function.

[0036] S113. Based on the preferred fitting function, obtain the theoretical control thickness of the roll at each monitoring point, and record the difference between the thickness at each monitoring point and the theoretical control thickness as the fluctuation thickness.

[0037] Specifically, the theoretical control thickness of the roll is obtained by substituting all independent variables into the optimal fitting function to obtain the theoretical control thickness of the roll at each monitoring point.

[0038] S114. Record each monitoring point where the fluctuation thickness is not zero as a local fluctuation point.

[0039] This invention measures the thickness of each monitoring point along the width of the incoming plate in real time at the mill inlet, analyzes the fluctuating thickness at each monitoring point of the incoming plate to identify local fluctuation points, and thus captures the interference factor of local thickness fluctuation of the incoming material in advance, thereby improving the pertinence of plate shape control.

[0040] S2. Determine the temperature compensation amount at each monitoring point of the roll and analyze the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device.

[0041] Considering that overall adjustment using only the crown adjustment mechanism cannot achieve precise matching of local gaps in the rolls, it is difficult to match the thickness fluctuation differences at different monitoring points in the width direction of the incoming material. At the same time, considering the heat conduction effect between the monitoring points of the rolls, the temperature compensation of a single monitoring point will affect adjacent areas through heat transfer. If this effect is ignored, it will cause temperature compensation deviation, resulting in a mismatch between the roll temperature adjustment and the abnormal thickness area of ​​the incoming material.

[0042] Furthermore, considering that the cold rolling speed affects the heat exchange efficiency of the rolls and the adjustment effect of the cooling flow rate, the cooling flow rate required for a unit temperature change varies under different cold rolling speeds. Therefore, it is necessary to dynamically match the cooling adjustment parameters in combination with the actual cold rolling speed to ensure the accuracy of temperature compensation and the rationality of the pre-output of cooling flow rate.

[0043] Based on this, the specific implementation steps of S2 are as follows: S21, determine the temperature compensation amount of each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point. For example... Figure 2 As shown, the specific implementation method is as follows: S211, according to the distribution location of each local fluctuation point, the local fluctuation point and all monitoring points adjacent to each local fluctuation point are recorded as monitoring points to be adjusted.

[0044] S212. Extract the thermal expansion coefficient of the rolls and the radius of the cooling rolls from the background database of the roll shape control system. The thermal expansion coefficient is an inherent parameter of the roll material, which represents the radial expansion per meter of roll for every 1 degree Celsius increase in the temperature of the roll material.

[0045] S213. The radial thermal expansion per unit length of the roll is calculated by the ratio of the fluctuating thickness of each monitoring point to the radius of the cooling roll. The theoretical temperature compensation is obtained by comparing the ratio of the thermal expansion coefficient with the theoretical temperature compensation of the remaining monitoring points.

[0046] S214. Calculate the difference between the theoretical temperature compensation of each monitoring point to be adjusted and the monitoring points on its two adjacent sides, and record it as the adjacent compensation difference.

[0047] S215. Extract the heat transfer rate of the roll from the background database of the roll shape control system, and analyze the adjacent conduction correction amount by summing the adjacent compensation differences on both sides of each monitoring point to be adjusted and the heat transfer rate of the roll. Among them, when there is only one monitoring point on a certain monitoring point to be adjusted, the adjacent compensation difference of the adjacent monitoring points of the monitoring point to be adjusted is taken as the sum of the adjacent compensation differences on both sides.

[0048] In this embodiment, the adjacent conduction correction is calculated by multiplying the sum of the adjacent compensation differences on both sides of the monitoring point to be adjusted, the heat transfer rate of the roll, and the control cycle. The heat transfer rate is the temperature transfer amount between adjacent monitoring points per unit temperature difference per unit time, with units of 1 / s. Therefore, the temperature value transferred from the monitoring point to both sides per unit time can be obtained by multiplying the heat transfer rate by the sum of the adjacent compensation differences, and then multiplying this by the control cycle to obtain the conduction correction. In this embodiment, the control cycle is 1 second.

[0049] The specific method for obtaining the heat transfer rate is to conduct a cooling experiment on the cooling roll. A monitoring point is heated with a set gradient temperature value, and the temperature change of adjacent monitoring points is measured per unit time. The temperature value of the monitoring point after each heating is calculated and the temperature difference of the adjacent monitoring points before the current heating is calculated. The ratio of the temperature change of adjacent monitoring points to the temperature difference after each heating is calculated, and the average of all ratios is taken as the heat transfer rate of the roll.

[0050] It should be noted that, according to Fourier's law of heat conduction, under the condition that the thermal properties of the roll material are approximately constant and the spacing between monitoring points is fixed, the heat transfer rate between adjacent monitoring points is proportional to the temperature difference and is independent of the base temperature.

[0051] S216. The sum of the theoretical temperature compensation amount and the adjacent conduction correction amount of each monitoring point to be adjusted is recorded as the corresponding temperature compensation amount, and the temperature compensation amount of the remaining monitoring points is recorded as zero.

[0052] S22. Analyze the pre-output cooling flow rate of each cooling nozzle in the segmented cooling device based on the temperature compensation amount. The specific implementation steps are as follows: S221. Obtain the cold rolling speed of the cold rolling unit, and extract the cooling adjustment flow rate corresponding to the unit temperature change at the current cold rolling speed from the background database of the sheet shape control system.

[0053] In this embodiment, the cooling flow rate corresponding to the unit temperature change at the current cold rolling speed can be periodically measured and updated in the background database of the shape control system. During the rolling process, the temperature of each monitoring point of the roll is collected by a thermal imager, the change in cooling flow rate at each monitoring point is recorded, and the temperature change at the monitoring point before and after the collection is calculated. The ratio of the change in cooling flow rate to the temperature change is averaged at each monitoring point to calculate the cooling flow rate corresponding to the unit temperature change at the current cold rolling speed, and this ratio is input into the background database of the shape control system to update the historical data.

[0054] S222. Calculate the flow rate regulation amount of each monitoring point by multiplying the temperature compensation amount of each monitoring point with the cooling regulation flow rate corresponding to the unit temperature change.

[0055] S223. The flow rate adjustment at each monitoring point is summed with the initial cooling flow rate of the segmented cooling device to obtain the pre-output cooling flow rate of each corresponding cooling nozzle.

[0056] This invention determines the temperature compensation amount of each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point, and analyzes the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device based on the temperature compensation amount, avoiding temperature compensation deviation caused by ignoring heat conduction, so that the roll temperature adjustment can accurately correspond to the abnormal area of ​​incoming material thickness, thus improving the accuracy of adjustment.

[0057] S3. Extract the tension components of each monitoring point's tension value, construct a residual tension component array, and analyze and determine the plate shape type and the roll to be adjusted in the mill.

[0058] Considering that typical plate shape anomalies such as single-sided wave, medium wave, double-sided wave, and quarter-sided wave in cold-rolled thin plates correspond to specific laws of transverse tension distribution, the plate shape type can be accurately matched by decomposing the energy proportions of the primary, secondary, and quaternary tension components obtained from the tension deviation. In addition, considering that different plate shape types have different formation mechanisms, the corresponding roll adjustment methods and adjustment rolls have clear differences. It is necessary to determine the roll to be adjusted and the adjustment method based on the determined plate shape type to avoid ineffective adjustment and ensure the stability and adjustment efficiency of the rolling process.

[0059] Based on this, the specific implementation steps of S3 are as follows: S31, Measure the transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit, extract the tension components of each monitoring point, and construct a residual tension component array. The specific construction method is as follows: S311, Extract the required tension of qualified cold-rolled sheets from the background database of the sheet shape control system.

[0060] S312. Extract the tension value of each monitoring point from the transverse tension distribution data, calculate the tension deviation of each monitoring point by the difference with the required tension, and obtain the first tension component, second tension component and fourth tension component of each monitoring point by decomposition.

[0061] In this embodiment, the specific decomposition process is as follows: First, the distance from each monitoring point to the side edge of the incoming material plate is normalized to [-1, 1]. Then, the basis functions corresponding to the first, second, and fourth order shape patterns are predefined. In the field of cold-rolled sheet shape control, Legendre orthogonal polynomials are typically used as basis functions. Their specific expressions are as follows: .

[0062] in, These represent the basis functions corresponding to the first, second, and fourth order plate shapes, respectively. The specific coefficients are existing techniques in Legendre orthogonal polynomials, which will not be elaborated upon in this invention.

[0063] Next, the tension deviation signal is decomposed into a linear combination of the above basis functions, as shown in the following expression: .

[0064] in, This represents the tension deviation signal at each monitoring point. This represents the normalized distance of each monitoring point from the side edge of the incoming material plate. All are coefficients. The residual components representing each monitoring point are solved using the least squares method for their coefficients. This minimizes the sum of squares of the residual components. Based on the solution... The expressions for each basis function are obtained, and the independent variables are substituted into the expressions for each basis function to obtain the first-order tension component, the second-order tension component, and the fourth-order tension component. The process of solving for the coefficients using the least squares method is existing technology and will not be described in detail here.

[0065] S313. Based on the primary tension component, secondary tension component and quaternary tension component of each monitoring point, calculate the sum of the squares of the amplitudes of each tension component at each monitoring point on the cold-rolled sheet to obtain the energy value of each tension component, and record the tension component with the largest energy value as the primary tension component.

[0066] S314. Calculate the residual tension component by comparing the tension deviation at each monitoring point with the main force component, and form a residual tension component array.

[0067] S32. The plate shape type is determined by analyzing the proportion of each tension component. The specific analysis method is as follows: S321. If the main tension component is a primary tension component, then the plate shape type is determined to be a single-sided wave. Compare the magnitudes of the primary tension components of the two monitoring points closest to the two edges of the cold-rolled sheet in the width direction. The edge where the monitoring point with the larger primary tension component is located is the edge where the single-sided wave is located.

[0068] S322. If the main force component is a secondary tension component, calculate the average value of the secondary tension components of the two monitoring points closest to the two edges of the cold-rolled sheet in the width direction, and calculate the difference between the average value and the secondary tension component of the midpoint monitoring point.

[0069] S323. If the difference is negative, the plate shape type is determined to be a medium wave; if the difference is positive, the plate shape type is determined to be a double wave. When the difference is negative, it means that the tension in the middle of the cold-rolled sheet is greater, which easily forms a medium wave; conversely, when the tension on both sides is greater, it easily forms a double wave.

[0070] S324. If the claimed force component is a fourth tension component, then its plate shape type is determined to be a quarter wave.

[0071] S33. Determine the rolls to be adjusted in the rolling mill based on the plate shape type.

[0072] In this example, taking a six-roll mill as an example, the cold-rolled sheet has three rolls arranged side-by-side on both the top and bottom. The two rolls in contact with the cold-rolled sheet are the work rolls, the two rolls furthest from the sheet are the support rolls, and the roll between the work rolls and the support rolls is the intermediate roll. When the sheet shape is a single-sided wave, the roll to be adjusted is the support roll, and the adjustment method is roll tilting, with the tilting direction of the support roll determined according to the side of the wave. When the sheet shape is a medium wave or a double-sided wave, the roll to be adjusted is the intermediate roll or the work roll, and the adjustment method is roll bending. When the sheet shape is a quarter-wave, the roll to be adjusted is the intermediate roll or the work roll, and the adjustment method is roll shifting. The specific calculation and execution methods of the adjustment amount are all conventional practices in the field of rolling engineering, and will not be described in detail in this invention.

[0073] This invention measures the transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit, extracts the tension components of each monitoring point, determines the sheet shape type by analyzing the proportion of each tension component, and determines the mill rolls to be adjusted based on the sheet shape type. This transforms the sheet shape determination into a quantifiable data analysis process, avoids human judgment errors, and ensures the stability of the rolling process.

[0074] S4. Analyze abnormal monitoring points to determine the final cooling flow rate.

[0075] Considering that even after the main sheet shape adjustment, cold-rolled thin sheets may still have local minor shape defects, such defects are caused by abnormal residual tension, which cannot be accurately solved by conventional overall cooling control; and there is a normal fluctuation range in the residual tension component, so it is necessary to define the allowable residual range through statistical analysis, accurately identify abnormal monitoring points that exceed the range, and avoid misjudging normal tension fluctuations as abnormal defects.

[0076] Furthermore, considering the quantitative correlation between residual tension anomalies and cooling flow rate adjustment, the residual tension component-cooling flow rate conversion coefficient was determined through experiments to achieve accurate conversion from residual tension anomaly values ​​to cooling nozzle correction amounts. At the same time, combined with pre-output cooling flow rate for superposition correction, the cooling flow rate can specifically compensate for local plate shape defects.

[0077] Based on this, the specific implementation steps of S4 are as follows: S41, analyze the outliers in the residual tension component array to obtain the abnormal monitoring points. The specific implementation steps are as follows: S411, record each residual tension component in the residual tension component array that is greater than zero as a positive residual tension component, and record each residual tension component that is less than zero as a negative residual tension component.

[0078] S412. Calculate the mean and standard deviation of all positive residual tension components, and set the maximum allowable residual range using the mean and standard deviation. In this embodiment, the difference between the mean and three times the standard deviation is taken as the maximum allowable residual range.

[0079] S413. Similarly, based on the negative residual tension component, a minimum value of the allowable residual range is set, and the allowable residual range is obtained by combining the maximum value of the allowable residual range. Specifically, the mean and standard deviation of all negative residual tension components are calculated, and the sum of the mean and three times the standard deviation is used as the minimum value of the allowable residual range. The maximum value of the allowable residual range and the minimum value of the allowable residual range are combined to form the allowable residual range.

[0080] S414. If a certain residual tension component is not within the allowable residual range, it shall be recorded as an abnormal value, and the monitoring points corresponding to the abnormal value shall be recorded as abnormal monitoring points.

[0081] S42. Calculate the correction amount for the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring point. For example... Figure 3 As shown, the specific implementation steps are as follows: S421. By setting the cooling flow rate adjustment experiment, the test plate with uniform thickness is rolled by the rolling mill, and the areas on the incoming plate that are being rolled are defined as different monitoring groups according to the set time interval.

[0082] In this embodiment, the time interval is set to 3 seconds, but the implementer can also set other specific values.

[0083] S422. During the rolling process, all cooling nozzles of each monitoring group are sequentially adjusted according to the set flow rate change to obtain the flow rate change of each monitoring group. The tension of each monitoring point in each monitoring group after rolling is measured in real time to obtain the corresponding residual tension component array.

[0084] In this embodiment, the flow rate change is set to 10% of the maximum adjustable flow rate of the cooling nozzle. The implementer may also set other specific values.

[0085] S423. Based on the residual tension component arrays of adjacent monitoring groups, perform difference analysis to obtain the change in residual tension components at each monitoring point of each monitoring group.

[0086] S424. Obtain the average value of the residual tension component change at each monitoring point in each monitoring group, and perform a ratio analysis with the nozzle cooling flow rate change of the corresponding monitoring group to obtain the residual tension component-cooling flow rate conversion coefficient for each monitoring group.

[0087] S425. The average value of the residual tension component-cooling flow conversion coefficient of each group is taken as the residual tension component-cooling flow conversion coefficient of the cooling device.

[0088] S426. Based on the ratio analysis of the residual tension component of each abnormal monitoring point and the residual tension component of the cooling device to the cooling flow conversion coefficient, the correction amount of the corresponding cooling nozzle is obtained.

[0089] S43. Determine the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle. The specific implementation steps are as follows: S431. If a monitoring point is an abnormal monitoring point, then add the pre-output cooling flow rate of the corresponding cooling nozzle to the correction amount of the cooling nozzle to obtain the final cooling flow rate.

[0090] S432. Conversely, the pre-output cooling flow rate of the cooling nozzle corresponding to the monitoring point is taken as the final cooling flow rate. In a specific embodiment of the present invention, the final cooling flow rate is output by each cooling nozzle of the segmented cooling device, and the roll to be adjusted is adjusted simultaneously.

[0091] This invention obtains abnormal monitoring points by analyzing outliers in the residual tension component array, calculates the correction amount of the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring points, and determines the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle. This enables precise capture of local minor plate shape defects, completes local abnormality correction after main plate shape adjustment, and improves plate shape quality.

[0092] like Figure 4 As shown, a cold-rolled thin plate rolling shape control system includes: a fluctuation point identification module, a temperature compensation module, a rolling feedback module, a cooling flow correction module, and a strategy execution module. The modules are connected as follows: the fluctuation point identification module is connected to the temperature compensation module; the rolling feedback module is connected to both the temperature compensation module and the cooling flow correction module; and the strategy execution module is connected to the cooling flow correction module.

[0093] The fluctuation point identification module measures the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, and analyzes the fluctuation thickness of each monitoring point of the incoming plate to identify local fluctuation points.

[0094] The temperature compensation module determines the temperature compensation amount for each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point, and analyzes the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device based on the temperature compensation amount.

[0095] The rolling feedback module measures the transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit, extracts the tension components of each monitoring point, determines the sheet shape type by analyzing the proportion of each tension component, and determines the mill rolls to be adjusted based on the sheet shape type.

[0096] The cooling flow correction module analyzes outliers in the residual tension component array to obtain abnormal monitoring points, calculates the correction amount of the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring points, and determines the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle.

[0097] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0098] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0099] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0100] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0101] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the shape of cold-rolled thin sheets, characterized in that, include: The thickness of each monitoring point in the width direction of the incoming plate is measured in real time at the mill inlet, and the fluctuating thickness of each monitoring point of the incoming plate is analyzed to identify local fluctuation points. The temperature compensation amount of each monitoring point of the roll is determined based on the fluctuation thickness and distribution position of each local fluctuation point, and the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device is analyzed based on the temperature compensation amount. The transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit is measured, the tension components of each monitoring point are extracted, the residual tension component array is constructed, the sheet shape type is determined by analyzing the proportion of each tension component, and the mill roll to be adjusted is determined based on the sheet shape type. Anomaly monitoring points are obtained by analyzing outliers in the residual tension component array. The correction amount of the corresponding cooling nozzle is calculated based on the residual tension component of the anomaly monitoring point. The final cooling flow rate is determined by combining the pre-output cooling flow rate of each cooling nozzle. The analysis method for local fluctuation points includes: The projection points of each cooling nozzle of the segmented cooling device within the width area of ​​the incoming material plate are taken as monitoring points in the width direction of the incoming material plate. The thickness of each monitoring point is measured by a thickness gauge. The distance of each monitoring point from the side of the incoming material plate is taken as the independent variable and the thickness of the corresponding monitoring point is taken as the dependent variable. The optimal fitting function is determined by substituting the data into a preset polynomial function model. The theoretical control thickness of the roll at each monitoring point is obtained based on the optimal fitting function, and the difference between the thickness at each monitoring point and the theoretical control thickness is recorded as the fluctuation thickness. Each monitoring point with a non-zero fluctuation thickness is recorded as a local fluctuation point; The method for obtaining the temperature compensation amount at each monitoring point: Based on the distribution location of each local fluctuation point, the local fluctuation point and all monitoring points adjacent to each local fluctuation point are recorded as monitoring points to be adjusted; Extract the thermal expansion coefficient of the rolls and the radius of the cooling rolls from the background database of the plate shape control system; The radial thermal expansion per unit length of the roll is calculated by the ratio of the fluctuating thickness of each monitoring point to the radius of the cooling roll. The theoretical temperature compensation is obtained by comparing this with the coefficient of thermal expansion. The theoretical temperature compensation of the remaining monitoring points is recorded as zero. Calculate the difference between the theoretical temperature compensation of each monitoring point to be adjusted and its two adjacent monitoring points, and record it as the adjacent compensation difference. The heat transfer rate of the roll is extracted from the background database of the roll shape control system. The adjacent conduction correction amount is analyzed by summing the compensation difference between adjacent monitoring points on both sides of each point to be adjusted and the heat transfer rate of the roll. The sum of the theoretical temperature compensation and the adjacent conduction correction for each monitoring point to be adjusted is recorded as the corresponding temperature compensation, and the temperature compensation for the remaining monitoring points is recorded as zero.

2. The method for controlling the shape of cold-rolled thin plates according to claim 1, characterized in that, The method for obtaining the pre-output cooling flow rate of each cooling nozzle includes: The cold rolling speed of the cold rolling unit is obtained, and the cooling adjustment flow rate corresponding to the unit temperature change at the current cold rolling speed is extracted from the background database of the sheet shape control system. The flow rate regulation amount at each monitoring point is calculated by multiplying the temperature compensation amount at each monitoring point with the cooling regulation flow rate corresponding to the unit temperature change. The pre-output cooling flow rate of each cooling nozzle is obtained by summing the flow rate adjustment at each monitoring point with the initial cooling flow rate of the segmented cooling device.

3. The method for controlling the shape of cold-rolled thin plates according to claim 1, characterized in that, The method for obtaining the residual tension component array includes: Extract the required tension of qualified cold-rolled thin plates from the backend database of the sheet shape control system; The tension values ​​of each monitoring point are extracted from the transverse tension distribution data. The tension deviation of each monitoring point is obtained by calculating the difference with the required tension. The first tension component, second tension component and fourth tension component of each monitoring point are obtained by decomposition. Based on the first, second and fourth tension components of each monitoring point, the sum of the squares of the amplitudes of each tension component at each monitoring point on the cold-rolled sheet is calculated to obtain the energy value of each tension component. The tension component with the largest energy value is recorded as the main tension component. The residual tension component is obtained by calculating the difference between the tension deviation at each monitoring point and the main force component, and then forming a residual tension component array.

4. The method for controlling the shape of cold-rolled thin plates according to claim 3, characterized in that, The analysis method for the plate shape type includes: If the force component is a primary tension component, then the plate shape type is determined to be a single-sided wave. If the main force component is a secondary tension component, calculate the average value of the secondary tension components of the two monitoring points closest to the two edges of the cold-rolled sheet in the width direction of the cold-rolled sheet, and calculate the difference between it and the secondary tension component of the midpoint monitoring point. If the difference is negative, the wave pattern is determined to be a medium wave; if the difference is positive, the wave pattern is determined to be a double wave. If the force component is a fourth-order tension component, then its plate shape type is determined to be a quarter-wave.

5. The method for controlling the shape of cold-rolled thin plates according to claim 1, characterized in that, The method for obtaining the anomaly monitoring points includes: Each residual tension component in the residual tension component array that is greater than zero is recorded as a positive residual tension component, and each residual tension component that is less than zero is recorded as a negative residual tension component. Calculate the mean and standard deviation of all positive residual tension components, and set the maximum allowable residual range using the mean and standard deviation; Similarly, the minimum value of the allowable residual range is set based on the negative residual tension component, and the maximum value of the allowable residual range is combined to obtain the allowable residual range; If a certain residual tension component is outside the allowable residual range, it is recorded as an outlier, and the monitoring points corresponding to the outlier are recorded as outlier monitoring points.

6. The method for controlling the shape of cold-rolled thin plates according to claim 1, characterized in that, The method for analyzing the correction amount of the cooling nozzle includes: By setting up a cooling flow rate adjustment experiment, a test sheet with uniform thickness was rolled through a rolling mill, and the areas on the incoming material sheet that were being rolled were sequentially defined as different monitoring groups according to a set time interval. During the rolling process, all cooling nozzles of each monitoring group are sequentially adjusted according to the set flow rate change to obtain the flow rate change of each monitoring group. The tension of each monitoring point in each monitoring group after rolling is measured in real time to obtain the corresponding residual tension component array. The variation of residual tension components at each monitoring point in each monitoring group is obtained by difference analysis based on the residual tension component arrays of adjacent monitoring groups. The average value of the residual tension component change at each monitoring point of each monitoring group is obtained, and the ratio of this value to the nozzle cooling flow rate change of the corresponding monitoring group is analyzed to obtain the residual tension component-cooling flow rate conversion coefficient of each monitoring group. The average value of the residual tension component-cooling flow conversion coefficient of each group is taken as the residual tension component-cooling flow conversion coefficient of the cooling device. The correction amount for the corresponding cooling nozzle is obtained by analyzing the ratio between the residual tension component of each abnormal monitoring point and the residual tension component of the cooling device and the cooling flow conversion coefficient.

7. The method for controlling the shape of cold-rolled thin plates according to claim 1, characterized in that, The method for obtaining the final cooling flow rate includes: If a monitoring point is an abnormal monitoring point, the pre-output cooling flow rate of the corresponding cooling nozzle is added to the correction amount of the cooling nozzle to obtain the final cooling flow rate. Conversely, the pre-output cooling flow rate of the cooling nozzle corresponding to the monitoring point is taken as the final cooling flow rate.

8. A method for controlling the rolling shape of cold-rolled thin plates according to any one of claims 1-7, wherein the method employs a cold-rolled thin plate rolling shape control system to complete the corresponding steps, characterized in that... The cold-rolled sheet forming control system includes: The fluctuation point identification module measures the thickness of each monitoring point in the width direction of the incoming plate in real time at the mill inlet, analyzes the fluctuation thickness of each monitoring point of the incoming plate, and identifies local fluctuation points. The temperature compensation module determines the temperature compensation amount for each monitoring point of the roll based on the fluctuation thickness and distribution position of each local fluctuation point, and analyzes the pre-output cooling flow rate of each cooling nozzle of the segmented cooling device based on the temperature compensation amount. The transverse tension distribution data of the cold-rolled sheet after rolling at the current mill exit is measured, the tension components of each monitoring point are extracted, the residual tension component array is constructed, the sheet shape type is determined by analyzing the proportion of each tension component, and the mill roll to be adjusted is determined based on the sheet shape type. The cooling flow correction module analyzes outliers in the residual tension component array to obtain abnormal monitoring points, calculates the correction amount of the corresponding cooling nozzle based on the residual tension component of the abnormal monitoring points, and determines the final cooling flow rate by combining the pre-output cooling flow rate of each cooling nozzle.

Images