A method for predicting and controlling wrinkling of a strip in a tandem cold rolling mill

Abstract

The application provides a cold continuous rolling mill set wrinkle strip break prediction and control method, comprising: obtaining basic parameters and force energy preset parameters of a strip steel to be analyzed; the force energy preset parameters comprise a pass speed, preset rolling forces of racks, preset unwinding tension, preset tension values between racks, a coiling tension and preset lubrication coefficients of the racks; in the rolling implementation, obtaining cold rolling process data of the strip steel being rolled; the cold rolling process data comprises an outlet plate thickness of the racks, actual rolling forces of the racks, actual unwinding tension, actual tension of the racks, actual coiling tension and actual lubrication coefficients of the racks; according to the plate thickness and strength of the strip steel to be analyzed, corresponding wrinkle prediction analysis and control are carried out based on the force energy preset parameters and the cold rolling process data thereof. The application proposes a wrinkle strip break prediction and control method suitable for different strength strip steels, can make up for the deficiencies of the prior art patents in the problem response, and can provide targeted solutions for the wrinkle strip break control of the cold continuous rolling process.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical engineering technology, and more specifically, it relates to a method for predicting and controlling wrinkle breakage in cold continuous rolling mills. Background Technology

[0002] Strip breakage during high-speed rolling is an abnormal production condition that disrupts production continuity, damages production equipment, and affects product quality. It also exhibits different states in base materials with different strengths. For low-strength, soft base materials, the high-speed strip breakage process involves a series of processes: "strip narrowing - edge tensioning - supercritical value breakage". Since the tension between units is highly correlated with the strip breakage process, abnormal tension changes can be regarded as a strip breakage warning signal, and the machine can be stopped in time. For example, the invention patent with application number 202110553111.5, "A method to reduce strip breakage due to deviation in cold continuous rolling mill", uses the tension meter reading to monitor the risk of strip breakage. Considering the correlation between plate shape detection and tension, the invention patent with application number 202211047918.2, "Strip breakage warning method and device based on plate shape evolution in ultra-thin strip rolling process", defines the deviation between the exit plate shape and the entrance plate shape as the strip breakage risk monitoring indicator. In addition, some invention patents take the perspective of "strip narrowing" and define the change in the width of the strip as the strip breakage risk monitoring indicator, such as the invention patent with application number 201410098802.0, "A control method to prevent strip breakage in the cold rolling process of thin strip steel". The above methods are suitable for detecting strip breakage in low-strength, soft materials, but they are difficult to apply to monitoring cold-rolled strip breakage in high-strength, hard materials. This is because high-strength, hard materials do not exhibit the same metal flow characteristics as low-strength materials during rolling. In the "rolling narrowing" stage of low-strength materials, they are prone to "local narrowing," which gradually deteriorates into "local wrinkling." Subsequently, the wrinkles force the downstream stand at their location to exhibit a series of behaviors such as "surging rolling force - large wrinkle deformation - local tearing of the rolled piece," ultimately resulting in strip fracture. Because this process involves drastic changes and apparent variations in multiple parameters, the above-mentioned methods alone are insufficient for accurate detection.

[0003] Against this backdrop, there is an urgent need to develop a method for predicting and controlling strip breakage during the cold rolling process of high-strength, hard base materials, based on the variation law and characteristics of the parameters during the cold rolling strip breakage process. This method would then provide assurance for the high-speed production of such cold-rolled base materials through continuous cold rolling. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for predicting and controlling strip breakage in cold continuous rolling mills.

[0005] A method for predicting and controlling strip breakage and wrinkling in a cold continuous rolling mill includes:

[0006] Obtain the basic parameters and preset force and energy parameters of the strip steel to be analyzed; the basic parameters include the coil number, plate thickness and strength; the preset force and energy parameters include the plate passing speed, the preset rolling force of the stand, the preset uncoiling tension, the preset tension value between the stands, the coiling tension and the preset lubrication coefficient of the stand;

[0007] During the rolling process, data on the cold rolling process of the strip being rolled are acquired; the cold rolling process data includes the exit plate thickness of the stand, the actual rolling force of the stand, the actual uncoiling tension, the actual tension of the stand, the actual coiling tension, and the actual lubrication coefficient of the stand.

[0008] Based on the thickness and strength of the strip to be analyzed, and using preset force and energy parameters and cold rolling process data, corresponding wrinkling prediction analysis and control are carried out.

[0009] Preferably, the step of performing corresponding wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, using preset force and energy parameters and cold rolling process data, includes:

[0010] When the thickness and strength of the strip to be analyzed exceed the preset thresholds, and it has not completely passed through all stands, the first single-stand independent analysis method is used to determine whether the strip to be analyzed has a risk of wrinkling; wherein, the first single-stand independent analysis method includes:

[0011] If the actual rolling force of a machine exceeds the preset rolling force by 20% and the exit plate thickness exceeds the preset thickness by 10%, it indicates that the machine is wrinkling and must be stopped immediately.

[0012] If a frame experiences an actual rolling force exceeding 12% of the preset rolling force, but the exit thickness does not exceed 10% of the preset thickness, it indicates that the frame has a wrinkling tendency.

[0013] When a frame shows signs of wrinkling, if the actual lubrication coefficient of the frame is higher than the preset lubrication coefficient and exceeds the preset lubrication coefficient by more than 20%, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine must be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but exceeds the preset lubrication coefficient by less than 20%, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the frame no longer shows signs of wrinkling.

[0014] Preferably, the step of performing corresponding wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, using preset force and energy parameters and cold rolling process data, further includes:

[0015] Once the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the first single-stand independent analysis method, the first-stand inter-linked analysis is used to complete the control of wrinkled strip breakage; the first-stand inter-linked analysis method includes:

[0016] If, in the cold rolling process data of two consecutive stands, the actual rolling force of the upstream stand exceeds the preset rolling force by 8%, while the actual rolling force of the downstream stand is less than 8% of the preset rolling force, it indicates that there is a risk of wrinkling in these two stands, and wrinkle breakage control measures are required. The methods for wrinkle breakage control include:

[0017] Compare the actual lubrication coefficient of the upstream rack with its preset lubrication coefficient. If the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped. If the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, the actual lubrication coefficient of the upstream rack can be increased by 5% of the preset lubrication coefficient until the risk of belt breakage due to wrinkles is eliminated.

[0018] If the cold rolling process data of two consecutive stands show that the actual rolling force of the upstream stand exceeds 8% of the preset rolling force, while the actual rolling force of the downstream stand is not lower than 8% of the preset rolling force, it indicates that there is no risk of wrinkling in these two stands and no wrinkle breakage control is required.

[0019] Preferably, the step of performing corresponding wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, using preset force and energy parameters and cold rolling process data, further includes:

[0020] When the thickness and strength of the strip to be analyzed are less than the preset threshold and it has not completely passed through all stands, the wrinkling index of the rolled piece for each stand is calculated, and the wrinkling trend is determined using the second single-stand independent analysis method; the formula for calculating the wrinkling index of the rolled piece for each stand is as follows:

[0021]

[0022] Where, k n F represents the wrinkling index of the rolled piece on the nth stand. n-r-n (t) represents the actual rolling force of the nth stand, F n-n T represents the preset rolling force of the nth stand. n-r-k (t) represents the actual unwinding tension, T n-k Indicates the preset unwinding tension, T n-r-n T represents the actual tension of the nth frame. n-n This represents the preset tension value for the nth frame.

[0023] Preferred, the second single-rack independent analysis method includes:

[0024] If the wrinkling index of the rolled piece of the stand exceeds 1.2, it indicates that wrinkling has occurred in the stand;

[0025] If the wrinkling index of the rolled piece of the frame exceeds 1.05 but is lower than 1.2, it indicates that the frame has a wrinkling tendency.

[0026] When the frame shows a tendency to wrinkle, if the actual lubrication coefficient is higher than the preset lubrication coefficient and the excess value is more than 20% higher than the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine needs to be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% higher than the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the wrinkling tendency is eliminated.

[0027] Preferably, after the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the second single-stand independent analysis method, the second two-stand linkage analysis and the three-stand linkage analysis are performed sequentially to complete the control of wrinkled strip breakage; wherein, the second two-stand linkage analysis includes:

[0028] If the wrinkling index of the rolled pieces on two consecutive stands is higher than 1, and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling on these two stands, and wrinkle breakage control is required. The wrinkle breakage control method is as follows: if the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped; if the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, or the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the stand can be increased by 5% of the preset lubrication coefficient until the risk of breakage is eliminated.

[0029] If the wrinkling index of the rolled piece on the upstream stand exceeds 1 while that on the downstream stand does not exceed 1, it is necessary to trace back to the upstream stand to find the source of the wrinkling risk.

[0030] Preferably, if the wrinkling index of the rolled piece in two consecutive stands is higher than 1, but the sum of their excesses does not exceed 0.05, then a three-stand linkage analysis is required; wherein, the three-stand linkage analysis method includes:

[0031] By tracing back to the upstream or downstream stand beyond the two consecutive stands, the relationship between the three stands is analyzed. If the wrinkling index of the rolled piece in all three stands is higher than 1 and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling in these three stands, and wrinkle breakage control is required. Among them, in the wrinkle breakage control, the adjustment of the actual lubrication coefficient of the stand should be targeted at the most upstream stand among the three stands.

[0032] If the total amount does not exceed 0.05, then the risk of wrinkling in these three racks can be ruled out.

[0033] The present invention also provides a wrinkle and strip breakage prediction and control system for cold continuous rolling mills, comprising:

[0034] The preset parameter acquisition module is used to acquire the basic parameters and preset force and energy parameters of the strip steel to be analyzed. The basic parameters include the coil number, plate thickness and strength. The preset force and energy parameters include the plate passing speed, the preset rolling force of the stand, the preset uncoiling tension, the preset tension value between the stands, the coiling tension and the preset lubrication coefficient of the stand.

[0035] The actual parameter acquisition module is used to acquire cold rolling process data of the strip being rolled during rolling. The cold rolling process data includes the exit plate thickness of the stand, the actual rolling force of the stand, the actual uncoiling tension, the actual tension of the stand, the actual coiling tension, and the actual lubrication coefficient of the stand.

[0036] The wrinkling analysis module is used to perform corresponding wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, the preset force and energy parameters, and the cold rolling process data.

[0037] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps in the above-described method for predicting and controlling wrinkled strip breakage in a cold continuous rolling mill.

[0038] The beneficial effects of the wrinkle and strip breakage prediction and control method provided by this invention for cold rolling mills are as follows: Compared with the prior art, this invention classifies cold-rolled base materials by utilizing the thickness and strength of the strip, and predicts the risk of wrinkle and strip breakage through independent analysis of each stand and joint analysis between stands by leveraging the correlation between rolling force fluctuations and tension fluctuations, and provides real-time control strategies for strip breakage prevention. Compared with previous patents, this invention proposes a wrinkle and strip breakage prediction and control method applicable to strips of different strengths, which can overcome the shortcomings of existing patents in addressing this problem. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0040] Figure 1 A flowchart of a method for predicting and controlling wrinkle breakage in a cold continuous rolling mill, provided in an embodiment of the present invention. Detailed Implementation

[0041] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0042] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0043] A method for predicting and controlling strip breakage and wrinkling in a cold rolling mill includes the following steps:

[0044] Step 100: Obtain the basic parameters and preset force and energy parameters of the strip steel to be analyzed; the basic parameters include the coil number, plate thickness and strength; the preset force and energy parameters include the plate passing speed, the preset rolling force of the stand, the preset uncoiling tension, the preset tension value between the stands, the coiling tension and the preset lubrication coefficient of the stand;

[0045] Step 200: During the rolling process, acquire the cold rolling process data of the strip being rolled; the cold rolling process data includes the exit plate thickness of the stand, the actual rolling force of the stand, the actual uncoiling tension, the actual tension of the stand, the actual coiling tension, and the actual lubrication coefficient of the stand;

[0046] Step 300: Based on the thickness and strength of the strip to be analyzed, perform corresponding wrinkling prediction analysis and control according to the preset force and energy parameters and the cold rolling process data.

[0047] Furthermore, step 300 includes:

[0048] Step 301: When the thickness and strength of the strip to be analyzed exceed the preset thresholds, and it has not completely passed through all stands, the first single-stand independent analysis method is used to determine whether the strip to be analyzed has a risk of wrinkling; wherein, the first single-stand independent analysis method includes:

[0049] If the actual rolling force of a machine exceeds the preset rolling force by 20% and the exit plate thickness exceeds the preset thickness by 10%, it indicates that the machine is wrinkling and must be stopped immediately.

[0050] Step 302: If the actual rolling force of the frame exceeds 12% of the preset rolling force, but the exit thickness does not exceed 10% of the preset thickness, it indicates that the frame has a wrinkling tendency.

[0051] Step 303: When the frame shows a wrinkling tendency, if the actual lubrication coefficient of the frame is higher than the preset lubrication coefficient and the excess value is more than 20% higher than the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine needs to be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% of the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the frame no longer shows a wrinkling tendency.

[0052] Step 304: After the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the first single-stand independent analysis method, the first-stand inter-linked analysis is used to complete the control of wrinkled strip breakage; wherein, the first-stand inter-linked analysis method includes:

[0053] If, in the cold rolling process data of two consecutive stands, the actual rolling force of the upstream stand exceeds the preset rolling force by 8%, while the actual rolling force of the downstream stand is less than 8% of the preset rolling force, it indicates that there is a risk of wrinkling in these two stands, and wrinkle breakage control measures are required. The methods for wrinkle breakage control include:

[0054] Compare the actual lubrication coefficient of the upstream rack with its preset lubrication coefficient. If the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped. If the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, the actual lubrication coefficient of the upstream rack can be increased by 5% of the preset lubrication coefficient until the risk of belt breakage due to wrinkles is eliminated.

[0055] Step 305: If the cold rolling process data of two consecutive stands show that the actual rolling force of the upstream stand exceeds 8% of the preset rolling force, while the actual rolling force of the downstream stand is not lower than 8% of the preset rolling force, it indicates that there is no risk of wrinkling in these two stands and no wrinkle breakage control is required.

[0056] Step 306: When the thickness and strength of the strip to be analyzed are less than the preset threshold and it has not completely passed through all stands, calculate the wrinkling index of the rolled piece for each stand, and use the second single-stand independent analysis method to complete the wrinkling trend determination; wherein, the formula for calculating the wrinkling index of the rolled piece for each stand is:

[0057]

[0058] Where, k n F represents the wrinkling index of the rolled piece on the nth stand. n-r-n (t) represents the actual rolling force of the nth stand, F n-n T represents the preset rolling force of the nth stand. n-r-k (t) represents the actual unwinding tension, T n-k Indicates the preset unwinding tension, T n-r-n T represents the actual tension of the nth frame. n-n This represents the preset tension value for the nth frame.

[0059] It should be noted that the second single-rack independent analysis method includes:

[0060] If the wrinkling index of the rolled piece of the stand exceeds 1.2, it indicates that wrinkling has occurred in the stand;

[0061] If the wrinkling index of the rolled piece of the frame exceeds 1.05 but is lower than 1.2, it indicates that the frame has a wrinkling tendency.

[0062] When the frame shows a tendency to wrinkle, if the actual lubrication coefficient is higher than the preset lubrication coefficient and the excess value is more than 20% higher than the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine needs to be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% higher than the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the wrinkling tendency is eliminated.

[0063] Step 307: After the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the second single-stand independent analysis method, the second two-stand linkage analysis and the three-stand linkage analysis are performed sequentially to complete the control of wrinkled strip breakage; among them, the second two-stand linkage analysis includes:

[0064] If the wrinkling index of the rolled pieces on two consecutive stands is higher than 1, and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling on these two stands, and wrinkle breakage control is required. The wrinkle breakage control method is as follows: if the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped; if the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, or the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the stand can be increased by 5% of the preset lubrication coefficient until the risk of breakage is eliminated.

[0065] Step 308: If the wrinkling index of the rolled piece on the upstream stand exceeds 1 while that on the downstream stand does not exceed 1, it is necessary to trace back to the upstream stand to find the source of the wrinkling risk.

[0066] Step 309: If the wrinkling index of the rolled piece in two consecutive stands is higher than 1, but the sum of the excesses does not exceed 0.05, then a three-stand linkage analysis is required; the three-stand linkage analysis method includes:

[0067] By tracing back to the upstream or downstream stand beyond the two consecutive stands, the relationship between the three stands is analyzed. If the wrinkling index of the rolled piece in all three stands is higher than 1 and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling in these three stands, and wrinkle breakage control is required. Among them, in the wrinkle breakage control, the adjustment of the actual lubrication coefficient of the stand should be targeted at the most upstream stand among the three stands.

[0068] Step 310: If the total amount of excess does not exceed 0.05, the risk of wrinkling in these three racks can be ruled out.

[0069] Please see Figure 1 The present invention will further illustrate the above process with reference to specific embodiments below:

[0070] Step S1: In the pre-coiling stage, collect the basic parameters of the strip steel to be rolled, including the coil number n and the plate thickness h. n and strength σ n Among them, the coil number 'n' serves as the marking number for the strip to be rolled, used to associate parameters throughout the cold continuous rolling process; the plate thickness 'h'... n and strength σ n It is used for predictive analysis of wrinkled and broken strips in strip steel to be rolled;

[0071] Step S2: In the rolling preparation stage, the preset force and energy parameters of the strip to be rolled are obtained from the secondary control system, including the coil number n and the plate speed v. n The preset rolling force (F) of the first to fifth stands n-1 F n-2 F n-3 F n-4 F n-5 ), preset unwinding tension T n-k The preset tension value (T) between the first to fifth frames n-12 T n-23 T n-34 T n-45 ), winding tension T n-c The preset lubrication coefficient (η) of the first to fifth frames n-1 η n-2 η n-3 η n-4 η n-5 The lubrication coefficient is calculated by using the ratio of the pre-added emulsion flow rate of the corresponding rack to the maximum emulsion flow rate of the rack, which represents the emulsion input capacity of the rack.

[0072] Step S3: During the rolling process, acquire real-time cold rolling process data of the strip being rolled from the data acquisition system, including the coil number n and the exit plate thickness [h] of the first to fifth stands. n-r-1 (t), h n-r-2 (t), h n-r-3 (t), h n-r-4 (t), h n-r-5 (t)], actual rolling force of the first to fifth stands [F n-r-1 (t), F n-r-2 (t), F n-r-3 (t), F n-r-4 (t), F n-r-5 [t], Actual unwinding tension T n-r-k (t), the actual tension of the first to fifth frames [T] n-r-12 (t), T n-r-23 (t), T n-r-34 (t), T n-r-45 [t], Actual winding tension T n-r-c(t), Actual lubrication coefficients of the first to fifth frames [η] n-r-1 (t), η n-r-2 (t), η n-r-3 (t), η n-r-4 (t), η n-r-5 (t)];

[0073] Step S4: Due to the continuous nature of cold rolling production, its process data also exhibits a continuous trend. It is necessary to distinguish the process data of each coil of strip steel according to different coil markings. Using the coil number n as an identifier, data matching is performed in real time for each coil of strip steel produced in cold rolling, and datasets for each coil of strip steel are generated.

[0074] Step S5: For cold-rolled base materials with high strength and large thickness (i.e., plate thickness h) n Greater than 3mm and strength σ n (Above 700MPa), lateral metal flow is difficult. Due to the unstable rolling process, wrinkles form rapidly and violently, making the wrinkling trend easy to predict, but requiring a wrinkle breakage control mechanism for rapid response. Real-time monitoring of the exit plate thickness and actual rolling force of the first to fifth stands is necessary, with comparative analysis performed against preset values ​​according to the time sequence.

[0075] Step S5-1: When the strip to be analyzed has not completely passed through all stands, but only passed through the i-th stand, compare and analyze the exit plate thickness and actual rolling force from the first to the i-th stands. Due to the influence of the order in which the strip passes through each stand, the closer it is to the i-th stand, the fewer the recorded exit plate thickness and actual rolling force data. Therefore, this stage can only perform independent analysis of the state of each stand, and cannot perform inter-stand linkage analysis.

[0076] Step S5-1-1: In response to this situation, at any time t during the production process... a If the actual rolling force of a certain stand exceeds 20% of the preset rolling force and the exit thickness exceeds 10% of the preset thickness, it indicates that the stand has experienced severe wrinkling and is about to break the strip, and the machine must be stopped immediately.

[0077] Step S5-1-2: If the actual rolling force of a certain stand exceeds 12% of the preset rolling force, but the exit thickness does not exceed 10% of the preset thickness, it indicates that the stand has a wrinkling tendency. The lubrication intensity of the stand can be increased. Then, compare the difference between the actual lubrication coefficient and the preset lubrication coefficient of the stand. If the actual lubrication coefficient is higher than the preset lubrication coefficient and the excess value is more than 20% of the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and strip breakage. The machine needs to be stopped to prevent strip breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% of the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the stand can be increased by 5% of the preset lubrication coefficient. This step process is repeated iteratively to predict and control strip breakage.

[0078] Step S5-1-3: If the above phenomenon does not occur, it indicates that there is no risk of wrinkling on the current rack and production can continue.

[0079] Step S5-2: When the strip to be analyzed has completely passed through all the stands, the parameters of each stand are now known, and independent analysis of a single stand and joint analysis between stands can be performed.

[0080] Step S5-2-1: Perform a single-rack independent analysis using the same method as in step S5-1;

[0081] Step S5-2-2: After analyzing the single rack independently and eliminating the risk of wrinkling, it is necessary to perform the inter-rack linkage analysis again.

[0082] Step S5-2-2-1: If the force monitoring data of two consecutive stands show that the actual rolling force of the upstream stand exceeds the preset rolling force by 8%, while the actual rolling force of the downstream stand is lower than the preset rolling force by 8%, it indicates that there is a risk of wrinkling in these two stands, and wrinkling and strip breakage control is required. Compare the actual lubrication coefficient of the upstream stand with its preset lubrication coefficient. If the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped. If the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, the actual lubrication coefficient of the upstream stand can be iteratively increased in the same way as in step S5-1-2 until the risk of strip breakage is eliminated.

[0083] Step S5-2-2-2: If the force monitoring data of two consecutive stands show that the actual rolling force of the upstream stand exceeds 8% of the preset rolling force, while the actual rolling force of the downstream stand is not lower than 8% of the preset rolling force, it indicates that there is no risk of wrinkling in these two stands and no wrinkling and strip breakage control is required.

[0084] Step S6: For cold-rolled base materials with low strength and low thickness (i.e., plate thickness h) n Less than 3mm and strength σ nFor cold-rolled materials with a pressure less than 700 MPa, lateral metal flow is relatively easy. Wrinkling formation in this type of cold-rolled material is slower than in the cold-rolled material involved in step S5, and the strip breakage behavior is less severe. Therefore, its wrinkling trend is difficult to detect, but the corresponding rate requirement for the control mechanism is relatively low. To achieve accurate prediction of wrinkling and strip breakage in this type of cold-rolled material, it is necessary to monitor the exit plate thickness of the first to fifth stands, the actual rolling force of the first to fifth stands, and the actual tension between the first to fifth stands in real time, and compare and analyze them according to the time sequence and preset values. The comparison of force and energy indicators uses the ratio of the percentage of rolling force exceeding the limit to the percentage of tension exceeding the limit for analysis, which is called the workpiece wrinkling index.

[0085] Wrinkling index of the first stand's rolled product

[0086] Wrinkling index of the rolled product on the second stand

[0087] Wrinkling index of the rolled product on the third stand

[0088] Wrinkling index of the rolled product in the fourth stand

[0089] Wrinkling index of the fifth stand

[0090] Step S6-1: When the strip to be analyzed has not completely passed through all stands, but only passed through the i-th stand, compare and analyze the exit plate thickness and actual rolling force from the first to the i-th stands. Due to the influence of the order in which the strip passes through each stand, the closer it is to the i-th stand, the fewer data such as exit plate thickness, actual rolling force, and actual tension are recorded. Therefore, this stage can only perform independent analysis of the state of each stand, and cannot perform inter-stand linkage analysis.

[0091] Step S6-1-1: In response to this situation, at any time t during the production process... a If the wrinkling index of the rolled piece in a certain stand exceeds 1.2, it indicates that the stand has experienced severe wrinkling and is about to break, and the machine must be stopped immediately.

[0092] Step S6-1-2: If the wrinkling index of a certain stand exceeds 1.05 but is lower than 1.2, it indicates that the stand has a wrinkling trend. The lubrication intensity of the stand can be selectively increased. Then, compare the difference between the actual lubrication coefficient and the preset lubrication coefficient of the stand. If the actual lubrication coefficient is higher than the preset lubrication coefficient and the excess value is more than 20% higher than the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and strip breakage. The machine needs to be stopped to prevent strip breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% higher than the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the stand can be increased by 5% of the preset lubrication coefficient. This step process is repeated iteratively to predict and control strip breakage.

[0093] Step S6-1-3: If the above phenomenon does not occur, it indicates that there is no risk of wrinkling on the current rack and production can continue.

[0094] Step S6-2: When the strip to be analyzed has completely passed through all the stands, the parameters of each stand are now known, and independent analysis of a single stand and joint analysis between stands can be performed.

[0095] Step S6-2-1: Perform single-rack independence analysis using the same method as in step S6-2;

[0096] Step S6-2-2: After analyzing the single rack independently and eliminating the risk of wrinkling, it is necessary to perform the linkage analysis between two racks and the linkage analysis between three racks again.

[0097] Step S6-2-2-1: If the wrinkling index of the rolled piece in two consecutive stands is higher than 1, and the sum of their excesses is greater than 0.05, it indicates that there is a risk of wrinkling in these two stands, and wrinkle breakage control is required. Compare the actual lubrication coefficient of the upstream stand with its preset lubrication coefficient. If the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped. If the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, the actual lubrication coefficient of the upstream stand can be iteratively increased in the same way as in step S6-1-2 until the risk of breakage is eliminated.

[0098] Step S6-2-2-2: If the wrinkling index of the rolled piece in the upstream stand exceeds 1 while that in the downstream stand does not exceed 1, it is necessary to trace back to the upstream stand to find the source of the wrinkling risk.

[0099] Step S6-2-2-3: If the wrinkling index of the rolled pieces in two consecutive stands is higher than 1, but the sum of their excesses does not exceed 0.05, then a three-stand linkage analysis is required.

[0100] Step S6-2-2-4: Based on step S6-2-2-3, trace back to the upstream or downstream stand of the three stands and analyze the relationship between them. If the wrinkling index of the rolled pieces of these three stands is higher than 1 and the sum of their excesses is greater than 0.05, it indicates that there is a risk of wrinkling in these three stands and wrinkle breakage control is required. The method for wrinkle breakage control follows step S6-1-2, but the stand for adjusting the lubrication coefficient must be the "first stand" among the three stands. If the sum of the excesses is not greater than 0.05, the risk of wrinkling in these three stands can be ruled out.

[0101] Compared with existing technologies, this invention proposes a method for predicting and controlling wrinkled strip breakage applicable to strips of different strengths. This method can overcome the shortcomings of existing patents in addressing this problem and provide a targeted solution for controlling wrinkled strip breakage in the cold rolling process.

[0102] This invention takes a cold rolling mill production line in a steel plant as an example and conducts an experimental demonstration on the prediction and control of wrinkle strip breakage in a cold rolling mill, as follows:

[0103] Step S1: In the pre-coiling stage, collect the basic parameters of the strip steel to be rolled (see Table 1), including the coil number n, plate thickness h. n and strength σ n .

[0104] Table 1

[0105] Steel coil number <![CDATA[Plate thickness h n > <![CDATA[Strength σ n > 0003976 3.2mm 723MPa 0007723 2.1mm 376MPa

[0106] Step S2: In the rolling preparation stage, obtain the preset force and energy parameters of the strip to be rolled from the secondary control system (see Table 2), including the coil number n and the plate speed v. n The preset rolling force (F) of the first to fifth stands n-1 F n-2 F n-3 F n-4 F n-5 ), preset unwinding tension T n-k The preset tension value (T) between the first to fifth frames n-12 T n-23 T n-34 T n-45 ), winding tension T n-c The preset lubrication coefficient (η) of the first to fifth frames n-1 η n-2 η n-3 η n-4 η n-5 The lubrication coefficient is calculated by using the ratio of the pre-added emulsion flow rate of the corresponding rack to the maximum emulsion flow rate of the rack, which represents the emulsion input capacity of the rack.

[0107] Table 2

[0108]

[0109] Step S3: During the rolling process, acquire real-time cold rolling process data of the strip being rolled from the data acquisition system, including the coil number n and the exit plate thickness [h] of the first to fifth stands. n-r-1 (t), h n-r-2 (t), h n-r-3 (t), h n-r-4 (t), h n-r-5 (t)], actual rolling force of the first to fifth stands [F n-r-1 (t), F n-r-2 (t), F n-r-3 (t), F n-r-4 (t), F n-r-5 [t], Actual unwinding tension T n-r-k (t), the actual tension of the first to fifth frames [T] n-r-12 (t), T n-r-23 (t), T n-r-34 (t), T n-r-45 [t], Actual winding tension T n-r-c (t), Actual lubrication coefficients of the first to fifth frames [η] n-r-1 (t), η n-r-2 (t), η n-r-3 (t), η n-r-4 (t), η n-r-5 (t)];

[0110] Step S4: Using the coil number n as an identifier, perform real-time data matching on each coil of steel produced by cold continuous rolling, and expand to generate a dataset for each coil of steel.

[0111] Step S5: In this embodiment, the strip steel with coil number 0003976 is a cold-rolled base material with high strength and large thickness. It is necessary to detect the exit plate thickness of the first to fifth stands and the actual rolling force of the first to fifth stands in real time, and compare and analyze them with the preset values ​​according to the time sequence.

[0112] Step S5-1: When the strip to be analyzed has not completely passed through all stands, but only through to the i-th stand, compare and analyze the exit plate thickness and actual rolling force of the first to the i-th stands. At any time during this stage, there are no instances of "the actual rolling force of a certain stand exceeding 20% ​​of the preset rolling force and the exit thickness exceeding 10% of the preset thickness" or "the actual rolling force of a certain stand exceeding 12% of the preset rolling force and the exit thickness not exceeding 10% of the preset thickness". Although there are instances of the actual rolling force of each stand exceeding the preset rolling force, the highest degree of excess is 9.73%, indicating that there is no risk of wrinkling in the current stand and production can continue.

[0113] Step S5-2: When the strip to be analyzed has completely passed through all the stands, the parameters of each stand are now known, and independent analysis of a single stand and joint analysis between stands can be performed.

[0114] Step S5-2-1: Using the same method as in step S5-1, after independent analysis of a single rack, there is still no risk of wrinkling at this stage;

[0115] Step S5-2-2: After analyzing the single-rack independently and eliminating the risk of wrinkling, an inter-rack linkage analysis needs to be performed again; board throughput time t a At 37s, abnormal data fluctuations occurred in stands S1 and S2. Specifically, the actual rolling force of stand S1 exceeded the preset rolling force by 8.33%, while the actual rolling force of stand S2 was 9.68% lower than the preset rolling force, indicating a risk of wrinkling in these two stands, requiring wrinkle and strip breakage control. The actual lubrication coefficients of stands S1 and S2 at this time were 0.51 and 0.55 respectively, both within 20% of the preset value. Therefore, the coefficients were increased to 0.54 and 0.58 respectively. Further monitoring revealed that the actual rolling force of stand S1 exceeded the preset rolling force by 7.63%, while the actual rolling force of stand S2 was 7.88% lower than the preset rolling force, thus eliminating the risk of strip breakage.

[0116] Step S6: In the two strip steel coils involved in this embodiment, the strip steel with coil number 0007723 is a cold-rolled base material with high strength and large thickness. The actual value of the wrinkling index of each stand is compared and analyzed with the preset value according to the time sequence.

[0117] Step S6-1: When the strip to be analyzed has not completely passed through all stands, but only through to the i-th stand, this stage only allows for independent analysis of each stand's status, and inter-stand linkage analysis is not possible; in this stage, at any time t a If no single stand has a wrinkling index exceeding 1.2, it indicates that there is no risk of wrinkling on the current stand, and production can continue.

[0118] Step S6-2: When the strip to be analyzed has completely passed through all the stands, the parameters of each stand are now known, and independent analysis of a single stand and joint analysis between stands can be performed.

[0119] Step S6-2-1: Using the same method as in step S6-1, after independent analysis of a single rack, there is still no risk of wrinkling at this stage;

[0120] Step S6-2-2: After independent analysis of a single stand and elimination of wrinkling risk, a linkage analysis between two stands and a linkage analysis between three stands need to be performed again. The test showed that there were no two consecutive stands where the wrinkling index of the rolled piece was higher than 1 and the total excess was greater than 0.05. However, it was found that the plate passage time t... a At 59s, the wrinkling indices of the rolled pieces on stands S2, S3, and S4 were 1.03, 1.01, and 1.01, respectively. The sum of the excess wrinkling indices of the three stands was exactly 0.05, indicating that there was a risk of wrinkling on these three stands and wrinkle breakage control was required. Subsequently, following the method in step S6-1-2, the lubrication coefficient of stand S2 was adjusted from the original value of 0.52 to 0.55. After follow-up testing, the wrinkling indices of the rolled pieces were 1.01, 1.01, and 1.00, respectively, which means that the risk of wrinkling had been eliminated.

[0121] The present invention also provides a wrinkle and strip breakage prediction and control system for cold continuous rolling mills, comprising:

[0122] The preset parameter acquisition module is used to acquire the basic parameters and preset force and energy parameters of the strip steel to be analyzed. The basic parameters include the coil number, plate thickness and strength. The preset force and energy parameters include the plate passing speed, the preset rolling force of the stand, the preset uncoiling tension, the preset tension value between the stands, the coiling tension and the preset lubrication coefficient of the stand.

[0123] The actual parameter acquisition module is used to acquire cold rolling process data of the strip being rolled during rolling. The cold rolling process data includes the exit plate thickness of the stand, the actual rolling force of the stand, the actual uncoiling tension, the actual tension of the stand, the actual coiling tension, and the actual lubrication coefficient of the stand.

[0124] The wrinkling analysis module is used to perform corresponding wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, the preset force and energy parameters, and the cold rolling process data.

[0125] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps in the above-described method for predicting and controlling wrinkled strip breakage in a cold continuous rolling mill.

[0126] Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present invention are the same as the beneficial effects of the cold continuous rolling mill wrinkle breakage prediction and control method described in the above technical solution, and will not be repeated here.

[0127] 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, and improvements 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 predicting and controlling strip breakage due to wrinkles in a cold continuous rolling mill, characterized in that, include: Obtain the basic parameters and preset force and energy parameters of the strip steel to be analyzed; The basic parameters include the steel coil number, plate thickness, and strength; The preset force parameters include the plate speed, the preset rolling force of the stand, the preset uncoiling tension, the preset tension value between the stands, the winding tension, and the preset lubrication coefficient of the stand. During the rolling process, acquire data on the cold rolling process of the strip being rolled. The cold rolling process data includes the exit plate thickness of the stand, the actual rolling force of the stand, the actual uncoiling tension, the actual tension of the stand, the actual coiling tension, and the actual lubrication coefficient of the stand. Based on the thickness and strength of the strip to be analyzed, and using preset force and energy parameters and cold rolling process data, corresponding wrinkling prediction analysis and control are carried out.

2. The method for predicting and controlling strip breakage in a cold continuous rolling mill as described in claim 1, characterized in that, The wrinkling prediction analysis and control based on the thickness and strength of the strip to be analyzed, pre-set force and energy parameters, and cold rolling process data includes: When the thickness and strength of the strip to be analyzed exceed the preset thresholds, and it has not completely passed through all stands, the first single-stand independent analysis method is used to determine whether the strip to be analyzed has a risk of wrinkling; wherein, the first single-stand independent analysis method includes: If the actual rolling force of the machine frame exceeds 20% of the preset rolling force and the exit plate thickness exceeds 10% of the preset thickness, it indicates that the machine frame is wrinkling and the machine must be stopped immediately. If the actual rolling force of a frame exceeds 12% of the preset rolling force, but the exit thickness does not exceed 10% of the preset thickness, it indicates that the frame has a wrinkling tendency. When a frame shows signs of wrinkling, if the actual lubrication coefficient of the frame is higher than the preset lubrication coefficient and exceeds the preset lubrication coefficient by more than 20%, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine must be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but exceeds the preset lubrication coefficient by less than 20%, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the frame no longer shows signs of wrinkling.

3. The method for predicting and controlling wrinkle and strip breakage in a cold continuous rolling mill as described in claim 2, characterized in that, The method of predicting and controlling wrinkling based on the thickness and strength of the strip to be analyzed, using preset force and energy parameters and cold rolling process data, also includes: Once the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the first single-stand independent analysis method, the first-stand inter-linked analysis is used to complete the control of wrinkled strip breakage; the first-stand inter-linked analysis method includes: If, in the cold rolling process data of two consecutive stands, the actual rolling force of the upstream stand exceeds the preset rolling force by 8%, while the actual rolling force of the downstream stand is less than 8% of the preset rolling force, it indicates that there is a risk of wrinkling in these two stands, and wrinkle breakage control measures are required. The methods for wrinkle breakage control include: Compare the actual lubrication coefficient of the upstream rack with its preset lubrication coefficient. If the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped. If the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, the actual lubrication coefficient of the upstream rack can be increased by 5% of the preset lubrication coefficient until the risk of belt breakage due to wrinkles is eliminated. If the cold rolling process data of two consecutive stands show that the actual rolling force of the upstream stand exceeds 8% of the preset rolling force, while the actual rolling force of the downstream stand is not lower than 8% of the preset rolling force, it indicates that there is no risk of wrinkling in these two stands and no wrinkle breakage control is required.

4. The method for predicting and controlling wrinkle and strip breakage in a cold continuous rolling mill as described in claim 3, characterized in that, The method of predicting and controlling wrinkling based on the thickness and strength of the strip to be analyzed, using preset force and energy parameters and cold rolling process data, also includes: When the thickness and strength of the strip to be analyzed are less than the preset threshold and it has not completely passed through all stands, the wrinkling index of the rolled piece for each stand is calculated, and the wrinkling trend is determined using the second single-stand independent analysis method; the formula for calculating the wrinkling index of the rolled piece for each stand is as follows: in, This represents the wrinkling index of the rolled piece in the nth stand. This represents the actual rolling force of the nth stand. This represents the preset rolling force of the nth stand. Indicates the actual unwinding tension. Indicates the preset unwinding tension. This represents the actual tension of the nth frame. This represents the preset tension value for the nth frame.

5. The method for predicting and controlling wrinkle breakage in a cold continuous rolling mill according to claim 4, characterized in that, The second single-rack independent analysis method includes: If the wrinkling index of the rolled piece of the stand exceeds 1.2, it indicates that wrinkling has occurred in the stand; If the wrinkling index of the rolled piece of the frame exceeds 1.05 but is lower than 1.2, it indicates that the frame has a wrinkling tendency. When the frame shows a tendency to wrinkle, if the actual lubrication coefficient is higher than the preset lubrication coefficient and the excess value is more than 20% higher than the preset lubrication coefficient, it indicates that the current lubrication system is exceeding its limit and cannot improve the wrinkling and belt breakage. The machine needs to be stopped to prevent belt breakage. If the actual lubrication coefficient is higher than the preset lubrication coefficient but the excess value is less than 20% of the preset lubrication coefficient, or if the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the frame can be increased by 5% of the preset lubrication coefficient until the wrinkling tendency is eliminated.

6. The method for predicting and controlling strip breakage in a cold continuous rolling mill according to claim 5, characterized in that, After the strip to be analyzed has completely passed through all stands and the risk of wrinkling has been eliminated through the second single-stand independent analysis method, the second two-stand linkage analysis and the three-stand linkage analysis are performed sequentially to complete the control of wrinkled strip breakage; among them, the second two-stand linkage analysis includes: If the wrinkling index of the rolled pieces on two consecutive stands is higher than 1, and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling on these two stands, and wrinkle breakage control is required. The wrinkle breakage control method is as follows: if the actual lubrication coefficient exceeds the preset lubrication coefficient by 20%, it cannot be adjusted and the machine must be stopped; if the actual lubrication coefficient does not exceed the preset lubrication coefficient by 20%, or the actual lubrication coefficient is lower than the preset lubrication coefficient, the actual lubrication coefficient of the stand can be increased by 5% of the preset lubrication coefficient until the risk of breakage is eliminated. If the wrinkling index of the rolled piece on the upstream stand exceeds 1 while that on the downstream stand does not exceed 1, it is necessary to trace back to the upstream stand to find the source of the wrinkling risk.

7. The method for predicting and controlling strip breakage in a cold continuous rolling mill as described in claim 6, characterized in that, If the wrinkling index of the rolled stock is higher than 1 for two consecutive stands, but the sum of the excesses does not exceed 0.05, then a three-stand linkage analysis is required. The methods for this analysis include: By tracing back to the upstream or downstream stand beyond the two consecutive stands, the relationship between the three stands is analyzed. If the wrinkling index of the rolled piece in all three stands is higher than 1 and the total excess is greater than 0.05, it indicates that there is a risk of wrinkling in these three stands, and wrinkle breakage control is required. Among them, in the wrinkle breakage control, the adjustment of the actual lubrication coefficient of the stand should be targeted at the most upstream stand among the three stands. If the total amount does not exceed 0.05, then the risk of wrinkling in these three racks can be ruled out.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps in the method for predicting and controlling wrinkled strip breakage in a cold rolling mill as described in any one of claims 1-7.

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