Method for correcting setting in threading process of hot continuous rolling finishing mill group
By sampling the actual rolling force in the hot strip finishing mill with a delay and calculating the roll gap correction, the problem of inaccurate thickness control at the finishing mill exit was solved, achieving high-precision thickness control and rolling stability, and preventing production accidents.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG GUANGQING METAL ROLLING CO
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-26
AI Technical Summary
In hot strip mill production, it is difficult to accurately predict the thickness control at the exit of the finishing mill. Adaptive resetting measures can easily lead to an increase in thickness deviation, which can increase the burden on downstream stand adjustment and may even cause production accidents.
By sampling the actual rolling force after the previous stand bites the steel, the actual rolling force lock value is calculated. The roll gap correction amount for the next stand is set according to the deviation, and the speed correction amount is calculated in reverse. The correction amount is passed on step by step to ensure the thickness accuracy of the exit head.
It achieves efficient control over the thickness of the outlet head, suppresses the expansion of thickness deviation, avoids drastic adjustments to the downstream stand, prevents production accidents, ensures rolling stability, and improves product quality.
Smart Images
Figure CN122076831A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metallurgical automation control technology, and in particular to a method for correcting settings during the strip threading process of a hot continuous rolling mill finishing unit. Background Technology
[0002] In the field of metal rolling, especially in modern hot strip rolling production lines, the finishing mill has long sought to ensure the head thickness hit rate by improving the prediction accuracy of the process control model. When the predicted value does not match the actual situation, the strip threading adaptive mechanism is activated to re-set the roll gap of the downstream stand. This serves as a backup means to compensate for model deviations. However, the method of real-time and dynamic linkage correction of the rolling parameters of the next stand during the strip threading process is relatively rare.
[0003] However, hot strip rolling systems have extremely high equipment precision requirements, strong inter-process coupling, significant dynamic interaction of process parameters, and complex production environment characteristics such as high temperature, high pressure, and high speed. During this process, the control model is easily affected by factors such as fluctuations in production conditions, the state of intermediate billets, equipment precision drift, and dynamic changes in strip threading of the finishing mill. It is difficult to ensure that every strip can be accurately predicted. Adaptive resetting remedial measures only adjust the downstream stand. This method can easily amplify the thickness deviation during the transmission process, which not only increases the adjustment burden of the downstream stand, but also, if the threading speed is too fast, the resetting data may not be effectively executed by the downstream AGC control system.
[0004] Improving the thickness accuracy of the strip head at the finish rolling exit and stabilizing the entire production line has become an important issue that urgently needs in-depth research and optimization in high-precision hot rolling production. A method is needed to suppress the expansion and transmission of thickness deviation from the source, so as to avoid the downstream stand from disrupting the steady state of the entire rolling line due to drastic adjustments, thereby causing product quality defects, or even production accidents such as rolling deviation and strip breakage. Summary of the Invention
[0005] The purpose of this invention is to provide a method for correcting settings during the strip threading process of a hot strip mill finishing unit in order to solve the above-mentioned problems.
[0006] The present invention achieves the above objectives through the following technical solutions: A method for correcting settings during the strip threading process of a hot strip mill finishing unit, specifically including the following steps: S1. After the strip is bitten by the previous stand, a certain time is delayed, the actual rolling force of the stand is sampled and the actual rolling force lock value is calculated. S2. Based on the deviation between the actual rolling force lock value and the predicted rolling force of the previous stand, calculate and set the roll gap correction amount for the next stand. The formula for calculating the roll gap correction amount for the next frame is as follows: △S i+1 P represents the roll gap correction amount for the next stand, in mm. i P is the actual rolling force lock value of the previous stand. s(i) The predicted rolling force for the previous stand is expressed in tons (m). i M is the stiffness coefficient of the previous frame. i+1 The stiffness coefficient of the next frame is given, in tons / mm, K. i+1 The plasticity coefficient of the strip for the next frame, in tons / mm, K. p(i+1) K is the roll gap correction factor for the next stand. p(i+1) The value ranges from 0.5 to 1.5, where i is the rack number; S3. Based on the roll gap correction amount of the next frame, calculate and compensate for the speed correction amount of the previous frame in reverse. The calculation formula is as follows: △V i V is the speed correction amount for the previous rack. i+1 The set speed for the next rack, in m / s and h. i The set exit thickness for the previous rack, in mm, K s(i) K is the speed correction factor for the previous rack. s(i) The value range is 0.5 to 1.5; S4. Following the above adjustment logic, the steel biting event is transmitted sequentially along the frame level by level; S5. After all frames have completed the steel clamping, reset all temporary corrections to zero.
[0007] Furthermore, the delay time T mentioned in step S1 acc The value range is 5 to 200, and the unit is ms. The controller sampling period TA ranges from 1 to 50, and the unit is ms. The number of samplings N ranges from 2 to 100. Furthermore, the formula for the actual rolling force locking value is as follows: The actual rolling force is locked at the specified value. The actual rolling force is given in tons, and i is the frame number.
[0008] Further, step S5 specifically involves setting the temporary correction value of all racks to 0 after all racks have a rising edge of the steel bite signal.
[0009] The beneficial effects are as follows: The method for correcting the setting during the strip threading process of the hot strip mill described in this invention is based on real-time sampling data. By implementing precise roll gap correction for the next stand during the strip threading process, it achieves efficient control of the thickness of the exit head. This improves the accuracy of the head thickness while suppressing the expansion and transmission of thickness deviation from the source, avoiding the disruption of the overall rolling steady state by the downstream stand due to drastic adjustments, and thus preventing product quality defects, or even production accidents such as rolling deviation and strip breakage. The algorithm of averaging multiple samples to lock the actual rolling force value can effectively suppress random fluctuations and anomaly detection interference, making the final sampled value closer to the actual rolling force distribution. This processing significantly improves the representativeness and stability of the sampling results and provides a reliable data basis for the accurate calculation of roll gap correction. The roll gap correction calculation establishes a quantitative mapping relationship between rolling force deviation and roll gap adjustment, accurately converting reliable sampling data into adjustment commands for the actuator. As the core hub connecting the front end and the back end, the accuracy and robustness of this algorithm directly determine whether the system can effectively convert the advantages of the front end data into accurate compensation for thickness deviation. It is the theoretical and execution basis for achieving high-precision thickness control. Speed correction calculation effectively maintains the balance of flow rate per second by actively compensating for the speed of the previous stand, avoiding system fluctuations caused by flow rate imbalance, thereby ensuring the steady state of rolling throughout the line, preventing accidents such as deviation and strip breakage, and providing a basic guarantee for the stability of the rolling process; Some parameters are given a range of values based on empirical values, which makes it easy to optimize them within the range according to different steel grades, rolling processes and equipment characteristics, thereby enhancing the universality and scalability of the method. For example, the roll gap correction coefficient of the next stand is in the range of 0.5 to 1.5, which can be adapted to a variety of rolling conditions. Attached Figure Description
[0010] Figure 1 This is a flowchart of a method for correcting settings during the strip threading process of a hot continuous rolling mill, as described in this invention. Detailed Implementation
[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0012] The following combination Figure 1 The invention is further described, specifically including the following steps: S1. After the strip is bitten by the previous stand, a certain time is delayed, the actual rolling force of the stand is sampled and the actual rolling force lock value is calculated. Among them, the empirical range of the given delay time Tacc is 5 to 200, and the unit is ms; the empirical range of the given controller sampling period TA is 1 to 50, and the unit is ms; the empirical range of the given number of samplings N is 2 to 100. The formula for the actual rolling force lock value is as follows: This is the actual rolling force lock value. The actual rolling force is expressed in tons, and i represents the mill stand number.
[0013] S2. Calculate and set the roll gap correction amount for the next stand based on the deviation between the actual rolling force lock value of the previous stand and the predicted rolling force. The formula for calculating the roll gap correction amount for the next stand is as follows: △S i+1 The roll gap correction amount for the next stand, in mm, P i P is the actual rolling force lock value of the previous stand. s(i) The predicted rolling force for the previous stand is given, in tons (m). i M is the stiffness coefficient of the previous frame. i+1 The stiffness coefficient of the next frame is given, in tons / mm, K. i+1 The plasticity coefficient of the strip for the next frame, in tons / mm, K. p(i+1) The empirical range for the roll gap correction factor for the next stand is 0.5 to 1.5, where i is the stand number.
[0014] S3. Based on the roll gap correction amount of the next stand, calculate and compensate for the speed correction amount of the previous stand in reverse. The formula for calculating the speed correction of the preceding frame is as follows: △V i V is the speed correction amount for the previous rack. i+1 The set speed for the next rack, in m / s (m). i+1 The stiffness coefficient of the next frame, in tons / mm, K. i+1 The plasticity coefficient of the strip for the next frame is expressed in ton / mm, ΔS. i+1 h is the roll gap correction amount for the next stand. i The set exit thickness for the previous rack, in mm, K s(i) K is the speed correction factor for the previous rack.s(i) The given empirical value range is 0.5 to 1.5, where i is the rack number.
[0015] S4. Following the above adjustment logic, the steel biting event is transmitted sequentially along the frame.
[0016] S5. After all frames have completed the steel clamping, reset all temporary corrections to zero.
[0017] Specifically, after all racks have a rising edge of the steel bite signal, the temporary correction value for all racks is set to 0.
[0018] The implementation process of the method of the present invention will be described below with reference to specific application examples.
[0019] In this application example, the number of racks is 7. Follow these steps: S1. After the strip bites into the F1 stand, wait for a period of time, then sample the actual rolling force of the F1 stand and lock it. In this embodiment, the delay time is set to 100ms, and the sampling formula for the actual rolling force of the F1 stand is as follows: The controller sampling period is 20ms, and the number of samples is 20. The results obtained after 20 samplings are shown in Table 1. Table 1 S2. Based on the deviation between the actual rolling force lock value of F1 stand and the predicted rolling force in S1, calculate and set the roll gap correction amount of F2 stand; In this embodiment, the formula for calculating the roll gap correction amount for frame F2 is: The roll gap correction factor for frame F2 is 1.1; The detailed data obtained from the calculations are shown in Table 2. Table 2 S3. Based on the roll gap correction amount of frame F2 described in S2, calculate and compensate for the speed correction amount of frame F1 in reverse. The formula for calculating the speed correction for the F1 frame is as follows: The speed correction factor for the F1 frame is 0.8, i.e., K. s(i) It is 0.8; The detailed data obtained from the calculations are shown in Table 3: Table 3 S4, Steps 1, 2, and 3 are adjusted in sequence according to the F2, F3, F4, F5, F6, and F7 rack steel biting events; In this embodiment, i is 7; S5. After all 7 racks have a steel bite signal rising edge, set the temporary correction value of all racks to 0.
[0020] Through the above embodiments, it can be found that the method for correcting and setting the strip threading process of the hot strip mill in actual production, after a certain period of effective signal delay, samples the actual rolling force of the stand, and then calculates and sets the roll gap correction amount for the next stand based on the deviation between the actual rolling force and the predicted rolling force. Then, based on the roll gap correction amount of the next stand, the speed correction amount of the previous stand is calculated and compensated in reverse. Then, as the steel biting event occurs, steps S1, S2, and S3 are repeated sequentially along the stand to solve the problem of low exit head thickness hit rate caused by process control model prediction deviation and interference from dynamic changes in strip threading of the finishing mill during actual rolling.
[0021] The method for correcting the setting during the strip threading process of this hot strip mill finishing unit is based on real-time sampling data. By implementing precise roll gap correction for the next stand, it achieves efficient control of the exit head thickness. This improves the head thickness accuracy while suppressing the expansion and transmission of thickness deviation at the source, preventing downstream stands from disrupting the overall rolling steady state due to drastic adjustments. Consequently, it prevents product quality defects, and even production accidents such as rolling deviation and strip breakage. This provides a more reliable solution for hot strip mill finishing units to improve head thickness accuracy while ensuring rolling stability, and has significant engineering application value and industry promotion significance.
[0022] Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.
Claims
1. A method for correcting settings during the strip threading process of a hot continuous rolling mill finishing unit, characterized in that, Includes the following steps: S1. After the strip is bitten by the previous stand, a certain delay is made, the actual rolling force of the stand is sampled and the actual rolling force lock value is calculated. S2. Based on the deviation between the actual rolling force lock value and the predicted rolling force of the previous stand, calculate and set the roll gap correction amount for the next stand. The formula for calculating the roll gap correction amount for the next frame is as follows: △S i+1 P represents the roll gap correction amount for the next stand, in mm. i P is the actual rolling force lock value of the previous stand. s(i) The predicted rolling force for the previous stand is expressed in tons (m). i M is the stiffness coefficient of the previous frame. i+1 The stiffness coefficient of the next frame is given, in tons / mm, K. i+1 The plasticity coefficient of the strip for the next frame, in tons / mm, K. p(i+1) K is the roll gap correction factor for the next stand. p(i+1) The value ranges from 0.5 to 1.5, where i is the rack number; S3. Based on the roll gap correction amount of the next frame, calculate and compensate for the speed correction amount of the previous frame in reverse. The calculation formula is as follows: △V i V is the speed correction amount for the previous rack. i+1 The set speed for the next rack, in m / s and h. i The set exit thickness for the previous rack, in mm, K s(i) K is the speed correction factor for the previous rack. s(i) The value range is 0.5 to 1.5; S4. According to the above adjustment logic, the steel biting event is passed along the frame level by level. S5. After all frames have completed the steel clamping, reset all temporary corrections to zero.
2. The method for correcting settings during the strip threading process of a hot continuous rolling mill as described in claim 1, characterized in that: The delay time T mentioned in step S1 acc The value ranges from 5 to 200, and the unit is ms. The controller sampling period TA ranges from 1 to 50, and the unit is ms. The number of samplings N ranges from 2 to 100.
3. The method for correcting settings during the strip threading process of a hot continuous rolling mill as described in claim 3, characterized in that: The formula for the actual rolling force lock value is as follows: The actual rolling force is locked at the specified value. The actual rolling force is given in tons, and i is the frame number.
4. The method for correcting settings during the strip threading process of a hot continuous rolling mill as described in claim 1, characterized in that: Step S5 specifically involves setting the temporary correction value of all racks to 0 after all racks have a rising edge of the steel bite signal.