A method for controlling the flatness of a hot continuous rolling finishing strip steel by adjusting the roll gap
By calculating the camber and deviation values between stands, and combining this with self-learning control, the problem of strip shape defects during hot rolling was solved, achieving stability and high-precision rolling of the strip threading process, thus improving production efficiency and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- МААНЬШАНЬ АЙРОН ЭНД СТИЛ КО ЛТД
- Filing Date
- 2023-03-23
- Publication Date
- 2026-07-21
AI Technical Summary
During the hot rolling process, asymmetric factors can cause strip shape defects such as sickle bends, deviations, and waviness, which affect rolling stability and equipment safety. Existing technologies rely on manual experience to adjust the roll gap, which lacks accuracy and reliability.
By calculating the sickle bend data and the deviation value between the frames, and combining it with real-time data on site, the strip threading roll gap leveling value is calculated. The leveling value is then corrected through a self-learning term to achieve feedforward and feedback control, thereby improving the stability of the threading process.
To ensure the stability of the strip during the threading process, improve rolling accuracy and product quality, reduce equipment downtime risks, and increase production efficiency.
Smart Images
Figure CN116174500B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of steel rolling automation technology, and in particular relates to a method for controlling the leveling of the strip threading roll gap in hot continuous rolling finishing strip. Background Technology
[0002] Due to the influence of asymmetric factors, strip steel will develop shape defects during hot rolling production. Among these, camber, deviation, and waviness in the roughing mill are major factors affecting the yield of high-precision strip steel. Due to the influence of rolling mill equipment and process parameters, the head of the strip exits the roughing mill exhibits significant lateral bending and serpentine bending. Upon entering the finishing mill, the deviation of the strip's centerline can cause it to impact the guide rails, affecting not only the stability of subsequent rolling and the final exit shape, but also potentially causing steel pile-up accidents. Furthermore, the impact on the rolling equipment can lead to equipment shutdowns for maintenance, severely impacting production efficiency. On-site operations mainly rely on operators with years of experience to adjust the roll gap difference in the finishing mill by pressing buttons on both sides of the rolls to correct head bending defects and reduce strip deviation. However, because the strip threading process is very complex, this method, entirely dependent on the experience of on-site personnel, lacks accuracy and reliability.
[0003] Chinese patent specification discloses a finishing mill strip threading leveling control method based on inter-stand deviation detection (publication number CN114713645A), and specifically discloses the following: "Different control strategies are adopted for F1 stand and F2 to F7 stands. For F1 stand, data obtained from intermediate billet measuring instruments is combined with vertical roll parameters to perform strip threading roll gap leveling control after the vertical roll bites the steel. For F2 to F7 entry deviation and F2 to F6 exit deviation, high-frequency cameras installed above the stand are directly collected. For F7 stand exit deviation, an exit multi-function instrument is used. Based on the entry deviation information collected by this stand, the strip threading roll gap leveling value of this stand is calculated. After the strip passes through this stand, the exit deviation value of this stand is collected by the camera above the next stand, and the stand is quickly adjusted a second time to realize feedforward + feedback adjustment of each finishing mill stand." This invention is applicable to the strip deviation control of hot rolling mills equipped with inter-stand detection devices, but the patent does not cover the strip head threading and leveling related control model, or the intermediate billet sickle bend and leveling self-learning control model. Summary of the Invention
[0004] I. Technical problems to be solved
[0005] This invention proposes a method for controlling the leveling of the strip threading roll gap in hot continuous rolling finishing strip, the purpose of which is to ensure the stability of the strip during the threading process, improve rolling accuracy, and guarantee product quality.
[0006] II. Technical Solution
[0007] This invention calculates the strip threading and leveling values for stands F1 to F3 based on the sickle-shaped bend data; then, it calculates the strip threading and leveling values for stands F1 to F6 based on the strip misalignment values between stands; finally, it calculates the self-learning item for the current strip threading process for the next coil's strip threading and leveling value. The specific steps include:
[0008] S1. Determine the deviation of the previous coil of steel on stands F1 to F3. If the deviation is not within a reasonable range, the camber control for this coil of steel will not be used. Otherwise, calculate the leveling value for the F1 to F3 stands based on the camber data using the following formula.
[0009]
[0010] In the formula, For frame F1 to F3, the belt threading and leveling values are i=1, 2, 3; The sickle curve control coefficient is obtained from the empirical values and weighting coefficients of each frame; The degree of curvature of the sickle's curved head is obtained through a communication server; The average deviation of the front section of the intermediate billet is obtained through the communication server; The deviation value of the intermediate billet at the sampling point location is obtained from the communication server; the sampling point location x is determined by the following formula.
[0011]
[0012] In the formula, The empirical value for the required bending length of the sickle-shaped head is 5000mm; R2 L The length of the intermediate billet is obtained through the communication server; The total number of deviation points of the intermediate billet is obtained through the communication server;
[0013] S2. The rolling force values on both sides of the strip are acquired in real time via PLC, and the strip deviation value is acquired in real time via communication server. The changes in rolling force and deviation value are calculated at 150ms intervals. When the rolling force difference and deviation value have opposite signs, the strip threading and leveling values for stands F1 to F6 are calculated according to the strip head deviation value using the following formula.
[0014]
[0015] In the formula, The belt threading and leveling values are for frames F1 to F6, where i = 1, 2, 3, 4, 5, 6; The deviation control coefficient is obtained from the empirical values and weighting coefficients of each rack. The strip deviation value is calculated by taking the strip offset value with a CCD camera installed at the top of the rolling mill, and calculating the average deviation value in the array over 150ms. The camera takes pictures at a frequency of 15Hz.
[0016] S3. Obtain the actual measured value of the roller gap on site through PLC, and calculate the manual leveling value during the tape threading process.
[0017] F1 manual leveling value: F4 steel bite F1 roll gap measured value - F1 steel bite F1 roll gap measured value;
[0018] F2 manual leveling value: F5 steel bite F2 roll gap measured value - F2 steel bite F2 roll gap measured value;
[0019] F3 manual leveling value: F7 steel bite F3 roll gap measured value - F3 steel bite F3 roll gap measured value;
[0020] F4 manual leveling value: F4 roll gap measured value when F7 steel bite delay is 5s - F4 steel bite F4 roll gap measured value;
[0021] F5 manual leveling value: F5 roll gap measured value when F7 steel bite delay is 5s - F5 steel bite F5 roll gap measured value;
[0022] F6 manual leveling value: F6 roll gap measured value when F7 steel bite delay is 5s - F6 steel bite F6 roll gap measured value;
[0023] S4. Calculate the strip threading leveling values for stands F1 to F6 based on the strip misalignment values between stands, and compare them with the manual leveling values during the strip threading process of this coil to determine if the directions are consistent. For stands F1-F6, if they are in the same direction, then...
[0024]
[0025] In the formula, The self-learning leveling value for the Fi rack's strapping; The self-learning coefficient for the Fi rack is obtained from the empirical values and weighting coefficients of each rack. The values for manual intervention during the Fi rack tape threading process are obtained via PLC, i=1, 2, 3, 4, 5, 6; if reversed, then...
[0026]
[0027] In the formula, The reverse self-learning coefficients for the Fi rack are obtained from the empirical values and weighting coefficients of each rack, i=1, 2, 3, 4, 5, 6;
[0028] For the F7 rack
[0029]
[0030] In the formula, Fi represents the rack self-learning coefficient, obtained from the empirical values and weighting coefficients of each rack, i=7;
[0031] S5. Record the self-learning items for this strip threading process, which will be used for the pre-positioning of the roll gap of the next coiled strip.
[0032] Furthermore, the sampling point position x mentioned in step S1 refers to the distance between the sampling point and the head of the sickle.
[0033] Furthermore, in step S2, the calculation of the change in rolling force and deviation value over a 150ms time interval involves storing the rolling force and deviation values into corresponding arrays, calculating the mean of the corresponding arrays every 150ms, and obtaining the difference in rolling force and deviation value from the mean values of adjacent arrays. The results are then stored in the server.
[0034] III. Beneficial Effects
[0035] This invention discloses a method for controlling the leveling of the strip threading roll gap in hot continuous rolling finishing strip. This method uses the camber of the incoming material from the roughing mill to provide feedforward control of the threading process; it uses real-time measured misalignment between stands to provide feedback control of the threading process; and it calculates a self-learning term for threading by comparing the direction of operator intervention with the model's calculated value, thereby correcting the threading leveling value. This ensures the stability of the strip during the threading process, improves rolling accuracy, and guarantees product quality. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of the process for controlling the leveling of the strip gap in hot continuous rolling finishing strip according to the present invention. Detailed Implementation
[0037] The specific embodiments of the present invention will be described in further detail below to enable those skilled in the art to understand them more clearly.
[0038] Example
[0039] The embodiments of the present invention employ the following steps:
[0040] S1. Determine that the deviation of the previous steel coil F1 to F3 frames is within a reasonable range. Calculate the leveling value of the F1 to F3 frames based on the camber data. First, calculate the sampling point position X of the camber using the following formula (1).
[0041] (1)
[0042] in:
[0043] The empirical value for the required bending length of the sickle-shaped head is 5000mm; R2 L The length of the intermediate billet is obtained through the communication server, and its value is 5531 mm. The total number of points where the intermediate billet deviates is obtained through the communication server, and its value is 553mm; the distance x between the sampling point and the head of the sickle bend is calculated to be 500mm.
[0044] S2. The communication server obtains the average deviation value of the front section of the intermediate billet at the sampling point. and the degree of curvature of the sickle head Value, from the formula The deviation value of the intermediate billet at the sampling point was calculated. The strip deviation value is obtained by calculating the average deviation value of the array within 150ms using the strip offset value captured by a CCD camera installed at the top of the rolling mill. The camera captured images at a frequency of 15Hz, and the data is shown in Table 1:
[0045] Table 1
[0046]
[0047] The empirical values and weighting coefficients for each rack on site are shown in Table 2:
[0048] Table 2
[0049]
[0050] Therefore, the calculated belt threading and leveling values for frames F1 to F6 are as follows:
[0051]
[0052] In the formula: The curvature of the sickle head is -25.45mm.
[0053] S3. The manual operation values for each rack on site are obtained through the PLC, as shown in Table 3:
[0054] Table 3
[0055]
[0056] S4. Compare the leveling values for strip threading on stands F1-F6 with the manual leveling values during the strip threading process to determine if the directions are consistent. For stands F1-F6, if they are in the same direction, then...
[0057]
[0058] In the formula, The self-learning leveling value for the Fi rack's strapping; The self-learning coefficient for the Fi rack is obtained from the empirical values and weighting coefficient data table for each rack. The values for manual intervention during the Fi rack tape threading process are obtained via PLC, i=1, 2, 3, 4, 5, 6; if reversed, then...
[0059]
[0060] In the formula, The reverse self-learning coefficients for rack Fi are obtained from the empirical values and weighting coefficient data table for each rack; i = 1, 2, 3, 4, 5, 6.
[0061] For the F7 rack
[0062]
[0063] In the formula, Fi represents the rack self-learning coefficient, obtained from the table of empirical values and weighting coefficients for each rack, i=7;
[0064] Since the manual operation values and the belt threading and leveling values of racks F1 to F6 in this embodiment are in the same direction, the same-direction self-learning coefficient is used. The relevant empirical values and weighting coefficients of each rack on site are shown in Table 4:
[0065] Table 4
[0066]
[0067] The self-learning terms for pre-positioning the roll seam of the lower strip steel, calculated accordingly, are as follows:
[0068]
[0069] S5. Record the self-learning items for this strip threading process, which will be used for the pre-positioning of the roll gap of the next coiled strip.
[0070] This invention discloses a method for controlling the leveling of the strip threading roll gap in hot continuous rolling finishing strip. This method uses the camber of the incoming material from the roughing mill to provide feedforward control of the threading process; it uses real-time measured misalignment between stands to provide feedback control of the threading process; and it calculates a self-learning term for threading by comparing the direction of operator intervention with the model's calculated value, thereby correcting the threading leveling value. This ensures the stability of the strip during the threading process, improves rolling accuracy, and guarantees product quality.
[0071] This invention is not limited to the specific embodiments described above. Any improvements made to the technical solutions by those skilled in the art based on the concept of this invention should fall within the scope of protection claimed by this invention.
Claims
1. A method for controlling the leveling of the strip threading roll gap in hot continuous rolling finishing strip, characterized in that, Calculate the strip threading and leveling values for stands F1 to F3 based on the sickle curve data; then calculate the strip threading and leveling values for stands F1 to F6 based on the strip misalignment values between stands; finally, calculate the self-learning items for this strip threading process to use as the strip threading and leveling values for the next coil of strip. This process includes the following steps: S1. Determine the deviation of the previous coil of steel on stands F1 to F3. If the deviation is not within a reasonable range, the camber control for this coil of steel will not be used. Otherwise, calculate the leveling value for the F1 to F3 stands based on the camber data using the following formula. In the formula, For frame F1 to F3, the belt threading and leveling values are i=1, 2, 3; The sickle curve control coefficient is obtained from the empirical values and weighting coefficients of each frame; The degree of curvature of the sickle's curved head is obtained through a communication server; The average deviation of the front section of the intermediate billet is obtained through the communication server; The deviation value of the intermediate billet at the sampling point location is obtained from the communication server; the sampling point location x is determined by the following formula. In the formula, The required length for the curved head of the sickle is empirically estimated at 5000 mm. The length of the intermediate billet is obtained through the communication server; The total number of deviation points of the intermediate billet is obtained through the communication server; S2. The rolling force values on both sides of the strip are acquired in real time via PLC, and the strip deviation value is acquired in real time via communication server. The changes in rolling force and deviation value are calculated at 150ms intervals. When the rolling force difference and deviation value have opposite signs, the strip threading and leveling values for stands F1 to F6 are calculated according to the strip head deviation value using the following formula. In the formula, The belt threading and leveling values are for frames F1 to F6, where i = 1, 2, 3, 4, 5, 6; The deviation control coefficient is obtained from the empirical values and weighting coefficients of each rack. The strip deviation value is calculated by taking the strip offset value with a CCD camera installed at the top of the rolling mill, and calculating the average deviation value in the array over 150ms. The camera takes pictures at a frequency of 15Hz. S3. Obtain the actual measured value of the roller gap on site through PLC, and calculate the manual leveling value during the tape threading process. F1 manual leveling value: F4 steel bite F1 roll gap measured value - F1 steel bite F1 roll gap measured value; F2 manual leveling value: F5 steel bite F2 roll gap measured value - F2 steel bite F2 roll gap measured value; F3 manual leveling value: F7 steel bite F3 roll gap measured value - F3 steel bite F3 roll gap measured value; F4 manual leveling value: F4 roll gap measured value when F7 steel bite delay is 5s - F4 steel bite F4 roll gap measured value; F5 manual leveling value: F5 roll gap measured value when F7 steel bite delay is 5s - F5 steel bite F5 roll gap measured value; F6 manual leveling value: F6 roll gap measured value when F7 steel bite delay is 5s - F6 steel bite F6 roll gap measured value; S4. Calculate the strip threading leveling values for stands F1 to F6 based on the strip misalignment values between stands, and compare them with the manual leveling values during the strip threading process of this coil to determine if the directions are consistent. For stands F1-F6, if they are in the same direction, then... In the formula, The self-learning leveling value for the Fi rack's strapping; The self-learning coefficient for the Fi rack is obtained from the empirical values and weighting coefficients of each rack. The values for manual intervention during the Fi rack tape threading process are obtained via PLC, i=1, 2, 3, 4, 5, 6; if reversed, then... In the formula, k diff_i The reverse self-learning coefficients for the Fi rack are obtained from the empirical values and weighting coefficients of each rack, i=1, 2, 3, 4, 5, 6; For the F7 rack In the formula, Fi represents the rack self-learning coefficient, obtained from the empirical values and weighting coefficients of each rack, i=7; S5. Record the self-learning items for this strip threading process, which will be used for the pre-positioning of the roll gap of the next coiled strip.
2. The method for controlling the leveling of the strip threading roll gap in hot continuous rolling as described in claim 1, characterized in that: The sampling point position x mentioned in step S1 refers to the distance between the sampling point and the curved head of the sickle.
3. The method for controlling the leveling of the strip threading roll gap in hot continuous rolling as described in claim 1, characterized in that: The calculation of the change in rolling force and deviation value at a 150ms time interval in step S2 involves storing the rolling force and deviation value into corresponding arrays, calculating the mean of the corresponding arrays every 150ms, and obtaining the rolling force difference and deviation value from the mean of adjacent arrays. The results are then stored in the server.