Three-point difference dynamic adjusting method in rolling process of hot-rolled strip steel

Abstract

The invention relates to the technical field of hot-rolled strips, in particular to a three-point difference dynamic adjusting method in the rolling process of hot-rolled strips, which comprises the following steps: S1, preparation before rolling and parameter initialization: roller shape matching and model parameter preloading; s2, dynamic regulation and control at the threading stage: thickness pre-compensation and temperature gradient suppression; s3, steady-state rolling control is conducted, specifically, three-point difference real-time monitoring and compensation are conducted, and thermal convexity dynamic compensation is conducted; and S4, drifting and exception handling: tail stability control and intelligent transition material insertion. According to the method, a full-process control system covering dynamic roll gap regulation and control, temperature-stress coupling compensation and intelligent decision support is constructed, and the problems that head and tail thickness fluctuation is difficult to restrain and edge thinning exceeds the standard by developing an asymmetric roll bending force distribution model and a rolling rhythm self-adaptive roll type matching strategy through traditional single-point thickness control can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of hot-rolled strip steel, and particularly to a dynamic adjustment method for three-point difference during the rolling process of hot-rolled strip steel. Background Art

[0002] In the production of hot-rolled strip steel, the thickness difference among the head, middle, and tail is simply referred to as the three-point difference, which is a core index affecting the strip shape quality. The formation of the three-point difference is complex and involves the coupling effects of multiple factors such as rolling process, equipment status, and temperature field distribution.

[0003] The traditional control method has the following systematic defects: Currently, the mainstream hot-rolled thickness control adopts a single-point automatic gauge control (AGC) system, which only performs closed-loop adjustment on the thickness of the strip middle part, making it difficult to suppress the thickness fluctuations at the head and tail. For the head thickness fluctuation, due to the unstable tension during the threading stage, the standard deviation of the head thickness is about 0.05 - 0.10 mm; for the tail, during the steel throwing stage of the tension loss effect, the tension suddenly drops, and the tail thickness deviation > 0.10 mm; the out-of-tolerance rate of the three-point difference: Under the traditional AGC system, the proportion of the three-point difference exceeding the control standard is relatively high, and additional edge trimming is required. The existing technology relies on a fixed roll changing cycle and cannot adapt to the dynamic production requirements, resulting in the following problems: Insufficient adaptation to fast-paced production: When the number of rolled pieces per hour > 35, the thermal crown of the roll accumulates at a rate of about 0.02 mm / 10 minutes, and the deterioration rate of the three-point difference in the second half of the rolling cycle increases significantly; during slow-paced rolling, the roll wears unevenly. When the production speed is < 20 pieces per hour, the local wear of the roll causes the roll gap to be asymmetric, and the thickness difference between the drive side and the operating side expands. The overall negative impact is low economic efficiency. Changing rolls based on a fixed rolling tonnage results in a waste of 10 - 15% of the remaining roll life, and the roll consumption per ton of steel increases by 0.05 kg / t. In addition, the temperature gradient in the finishing process has a particularly significant impact on the three-point difference. There are differences in the transverse temperature. When the temperature gradient at the entrance of the finishing mill > 25°C, the cooling rate difference between the strip edge and the middle part reaches 15 - 20%, causing metal transverse flow and resulting in wedge out-of-tolerance; when the waiting time in the reheating furnace is greater than 5 minutes, the temperature difference between the head and tail of the strip expands, the fluctuation range of the three-point difference increases, and the control response time is long. The existing system relies on manual experience to adjust the laminar cooling water volume, and the time required from temperature anomaly detection to compensation execution is too long, resulting in the proportion of out-of-tolerance coils reaching more than 10%.

[0004] Related patents on static bending roll force distribution propose an operating side / drive side bending roll force distribution strategy based on a fixed ratio, but they do not consider the influence of rolling rhythm and roll profile changes. Practical applications have also shown that during high-speed production, the bending roll force compensation is insufficient; the matching error of the roll change cycle is large, resulting in excessive wear of the rolls. The temperature gradient compensation method detects the transverse temperature distribution through an infrared thermometer and adjusts the laminar cooling water volume, but its limitation is that it does not establish a temperature-rolling force coupling model, and the residual temperature error after compensation is still large; it is only applicable to a single steel type such as low-carbon steel and has poor adaptability to medium-high carbon steels such as 65Mn. It cannot solve the stability problem of the three-point difference. In recent years, various improvement schemes have been proposed in the academic field, but there are still technical gaps. In terms of model predictive control, some studies use the MPC algorithm to optimize the roll gap setting, but do not integrate rolling rhythm parameters, and the adaptability to dynamic working conditions in actual production is insufficient; some scholars have tried to use neural networks to predict the three-point difference, but the model relies on a large amount of historical data training and has poor generalization ability for new steel types and new specifications; some attempts use virtual rolling simulation to optimize process parameters, but the real-time performance is insufficient and it is difficult to be used for online control.

[0005] At present, the quality requirements of downstream users have been upgraded. With the growth of the demand for high-end products such as automotive sheets and household appliance sheets, users' requirements for the thickness uniformity of strip steel are becoming increasingly stringent: 1. Strip steel with a three-point difference > 0.05 mm will cause fluctuations in cold rolling force, leading to a risk of strip breakage. According to relevant literature, the probability of increase can reach about 20%; 2. Surface quality index: Exceeding the standard of the three-point difference will cause uneven coating thickness, resulting in an increase in the scrap rate of automotive outer panels; 3. Yield bottleneck: Under the traditional process, the trimming amount due to the exceeding of the three-point difference accounts for 1.5 - 2.0% of the total width of the strip steel. Especially when producing products with a relatively narrow width, the trimming amount will be higher; 4. Energy consumption and emission reduction pressure: The rolling of redundant transition materials increases gas consumption, resulting in too high carbon emission intensity. Summary of the Invention

[0006] Aiming at the above problems, the purpose of the present invention is to provide a method for dynamically adjusting the three-point difference during the hot rolling process of strip steel. Taking process optimization and intelligent upgrading as the core path, a full-process control system covering dynamic roll gap control, temperature-stress coupling compensation, and intelligent decision support is constructed. By developing an asymmetric bending roll force distribution model and a roll profile matching strategy adaptive to the rolling rhythm, it can effectively solve the problems that traditional single-point thickness control is difficult to suppress the thickness fluctuations at the head and tail and the edge thinning exceeding the standard.

[0007] The technical solution adopted by the present invention is as follows: A method for dynamically adjusting the three-point difference during the hot rolling process of strip steel proposed by the present invention includes the following steps: S1. Preparation before rolling and parameter initialization: Roll profile matching, preloading of model parameters; S2. Dynamic control during the threading stage: Thickness pre-compensation, temperature gradient suppression; S3. Steady-state rolling control: real-time monitoring and compensation of the three-point difference, dynamic compensation of thermal crown; S4. Tail whipping and abnormal handling: tail stability control, intelligent transition material insertion.

[0008] Furthermore, in the step S1, the roll profile is selected according to the production plan: when rolling at a high pace, the camber is 0.12 - 0.15 mm to suppress the thermal crown; when rolling at a slow pace, the camber is 0.05 - 0.08 mm to reduce wear; when rolling the conditioning material after roll change: roll 5 - 8 transition materials, set the initial bending roll force to 80% of the reference value, and increase it by 5% for each material until full load.

[0009] Furthermore, in the step S1, the preloading of the model parameters includes: calling the historical optimal parameters of the same specification from the digital twin platform; calibrating the detection instruments: the zero error of the laser thickness gauge is ≤ 0.005 mm, and the deviation of the infrared thermometer is ≤ ±3°C.

[0010] Furthermore, in the step S2, the thickness pre-compensation includes: predicting the thickness deviation based on the temperature at the strip head, pre-adjusting the roll gap by 0.10 - 0.30 mm, where for every 10°C decrease in temperature, the roll gap compensation is +0.05 mm; the bending roll force starts at 90% of the reference value and linearly increases to 100% within 10 seconds.

[0011] Furthermore, in the step S2, the suppression of the temperature gradient includes: temporarily reducing the side cooling water volume to 80% of the standard value to reduce the temperature drop during threading; stabilizing the rolling speed within 30 meters at the head at 4.50 - 4.60 m / s.

[0012] Furthermore, in the step S3, the real-time monitoring and compensation of the three-point difference includes: Calculating the three-point difference: .

[0013] where h L is the thickness on the operator side; hc is the thickness in the middle; h T is the thickness on the drive side; ΔH is the three-point difference; Hierarchical response: When ΔH is 0.05 - 0.08 mm, the bending roll force on the operator side increases by 6 - 10%; the reduction compensation on the drive side is 0.1 - 0.3 mm; the side cooling flow rate increases by 10 - 20%; When ΔH > 0.08 mm, the bending roll force on the operator side increases by 10 - 15%; the reduction compensation on the drive side is 0.3 - 0.5 mm; the side cooling flow rate increases by 20 - 30%.

[0014] Furthermore, in the step S3, the dynamic compensation of the thermal crown includes: updating the compensation amount every 18 - 22 rolls:

[0015] Among them, C h (t) is the thermal crown compensation amount; t is the rolling time; v is the rolling speed; N is the cumulative rolling count; The roller gap is fine-tuned by hydraulic AGC, and the compensation error is ≤±0.01mm.

[0016] Furthermore, in step S4, the tail stability control includes: reducing the rolling speed to 3.5-4.5 m / s 48-52 meters in advance, reducing the middle cooling water volume to 80-90%; and reducing the bending roll force in a step-by-step manner to 65-75% of the baseline value to suppress tail warping.

[0017] Furthermore, in step S4, the intelligent transition material insertion includes: when the predicted abnormal duration is greater than 5 minutes, inserting one gradual transition material, and compressing the transition section length to 14-16 meters.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Quality improvement: The three-point difference pass rate has been improved to the industry-leading level, meeting the stringent requirements of high-end cold-rolled substrates for thickness uniformity; 2. Cost optimization: Transition material consumption and roll wear rate were significantly reduced, and the production cost per ton of steel decreased year-on-year; 3. Green Manufacturing: Reduce energy consumption through process optimization and help achieve carbon emission reduction goals; 4. Intelligent upgrade: Equipment utilization and production flexibility are greatly improved, supporting efficient production of small batches and multiple varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a schematic flow chart of a method for dynamically adjusting three-point differences during the hot strip rolling process. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] It should be noted that, in the description of the present invention, the terms "up", "down", "top", "bottom", "one side", "the other side", "left", "right", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0022] See the appendix Figure 1 A dynamic adjustment method for the three-point difference during the hot rolling process of hot-rolled strip steel proposed by the present invention includes the following steps: S1. Preparation before rolling and parameter initialization: Roll profile matching: Select the roll profile according to the production plan: When rolling at a high speed (≥35 coils / hour), the camber is 0.12 - 0.15 mm to suppress the thermal crown; when rolling at a low speed (<25 coils / hour), the camber is 0.05 - 0.08 mm to reduce wear; When rolling the warm-up material after roll change: Roll 5 - 8 transition materials, and set the initial bending roll force to 80% of the reference value, increasing by 5% for each coil until full load.

[0023] Preloading of model parameters; Call the historical optimal parameters of the same specification (such as the finish rolling temperature, cooling intensity) from the digital twin platform; Calibrate the detection instruments: The zero error of the laser thickness gauge is ≤0.005 mm, and the deviation of the infrared thermometer is ≤±3°C.

[0024] S2. Dynamic regulation during the threading stage (speed ≤5 m / s): Thickness pre-compensation: Predict the thickness deviation based on the strip head temperature, and pre-adjust the roll gap by 0.10 - 0.30 mm. Among them, for every 10°C decrease in temperature, the roll gap compensation is +0.05 mm; The bending roll force starts at 90% of the reference value and linearly increases to 100% within 10 seconds.

[0025] Suppression of temperature gradient: Temporarily reduce the side cooling water volume to 80% of the standard value to reduce the temperature drop during threading; The rolling speed within the first 30 meters of the strip head is stabilized at 4.50 - 4.60 m / s.

[0026] S3. Steady-state rolling control: Real-time monitoring and compensation of the three-point difference: Calculate the three-point difference: .

[0027] Among them, h L is the thickness on the operator side; hc is the middle thickness; h T is the thickness on the drive side; ΔH is the three-point difference; Hierarchical response: When ΔH is 0.05 - 0.08 mm, the bending roll force on the operator side increases by 6 - 10%; The reduction compensation amount on the drive side increases by 0.1 - 0.3 mm; The side cooling flow rate increases by 10 - 20%; When ΔH > 0.08 mm, the bending roll force on the operator side increases by 10 - 15%; The reduction compensation amount on the drive side increases by 0.3 - 0.5 mm; The side cooling flow rate increases by 20 - 30%.

[0028] Dynamic compensation of thermal crown: Update the compensation amount every 18 - 22 coils:

[0029] Among them, C h (t) is the hot crown compensation amount; t is the rolling time; v is the rolling speed; N is the cumulative number of rolled coils; The roll gap is finely adjusted by hydraulic AGC, and the compensation error ≤ ±0.01 mm.

[0030] S4, Tail Flipping and Abnormality Handling: Tail Stability Control: The rolling speed is reduced to 3.5 - 4.5 m / s 48 - 52 meters in advance, and the middle cooling water volume is reduced to 80 - 90%; the bending roll force is stepped down to 65 - 75% of the reference value to suppress tail warping.

[0031] Intelligent Transition Material Insertion: When the predicted abnormal duration > 5 minutes, insert 1 transition material with a gradually changing thickness (such as 6 mm → 5 mm → 4 mm), and the length of the transition section is compressed to 14 - 16 meters.

[0032] Preparation before Rolling and Parameter Initialization; Principle: Ensure that the equipment status and process parameters before rolling reach the optimal level, laying the foundation for the subsequent rolling process.

[0033] Specific Means and Purposes: Roll Profile Matching: Select a suitable roll profile according to the production plan. Choose a roll profile with a large concave degree to suppress hot crown during high - speed rolling, and choose a roll profile with a small concave degree to reduce wear during slow - speed rolling.

[0034] Purpose: Adapt to different rolling rhythms, reduce roll gap changes, and improve strip shape quality.

[0035] Model Parameter Preloading: Call the historical optimal parameters of the same specification from the digital twin platform and calibrate the detection instruments.

[0036] Purpose: Utilize historical data to optimize current rolling parameters, ensure measurement accuracy, and improve the stability and controllability of the rolling process.

[0037] Dynamic Adjustment during Threading; Principle: Pre - compensate for thickness and temperature during the threading stage to reduce the influence of thickness fluctuations and temperature gradients in the initial stage.

[0038] Specific Means and Purposes: Thickness Pre - compensation: Predict the thickness deviation based on the leading - end temperature and pre - adjust the roll gap.

[0039] Purpose: Compensate for the thickness change caused by temperature differences and ensure the thickness uniformity of the strip head.

[0040] Temperature Gradient Suppression: Reduce the side cooling water volume and stabilize the leading - end rolling speed.

[0041] Purpose: To reduce the temperature drop during threading and avoid lateral flow and wedge-shaped deviation caused by temperature gradient.

[0042] Steady-state rolling control; Principle: Real-time monitoring of the three-point difference and dynamic compensation, while taking into account the change of thermal crown, to maintain thickness uniformity during steady-state rolling.

[0043] Specific means and objectives: Real-time monitoring and compensation of three-point difference: By calculating the three-point difference and responding in stages, the bending force and edge cooling flow on the operating and transmission sides are adjusted.

[0044] Purpose: To correct thickness deviation in time, suppress thickness fluctuation at the head and tail, and improve the pass rate of three-point difference.

[0045] Dynamic compensation of thermal crown: Update the thermal crown compensation amount according to the rolling count, and fine-tune the roll gap through hydraulic AGC.

[0046] Purpose: To compensate for the change in roll gap caused by the change in thermal crown during rolling and to keep the thickness of the middle part of the strip stable.

[0047] tail-flick and exception handling; Principle: Control measures are taken during the tail swinging stage to reduce thickness fluctuation and warpage of the tail. At the same time, transition materials are inserted in time when abnormalities occur to maintain production stability.

[0048] Specific means and objectives: Tail stability control: reduce rolling speed, middle cooling water volume and bending roll force.

[0049] Purpose: To reduce thickness deviation and warping caused by tail tension loss effect and improve the quality of strip tail.

[0050] Smart transition material insertion: When the abnormality is predicted to last for a long time, a gradual transition material is inserted.

[0051] Purpose: To smoothly transition abnormal conditions and reduce strip waste and production interruptions caused by abnormalities.

[0052] The present invention will be further described below by means of specific embodiments: Example 1 Q235B, 6.0×790mm conventional steel Initial production conditions: Steel characteristics: C ≤ 0.10%, Mn 0.20-0.30%, typical low-carbon structural steel; Equipment parameters: Finishing mill stiffness 5800kN / mm, layer cooling system maximum water volume 200m 3 / h; Historical issues: The standard deviation of the three-point spread fluctuation is 0.07mm, the deviation rate is greater than 25%, and the yield rate is 89.3%.

[0053] Implementation of the technical solution: S1. Preparation before rolling: Select a roll profile with a large concave degree (0.12 mm). After changing the roll, roll 6 ironing roll materials (gradually changing in thickness from 7.0 to 6.5 mm); Preloaded parameters of the digital twin platform: finishing temperature 890 °C, reference value of bending roll force OS - 820 kN / DS - 780 kN.

[0054] S2. Threading stage: Detect the leading end temperature of 870 °C (20 °C lower than the target), and pre-compensate the roll gap by +0.25 mm; Set the side cooling water volume to 80% of the standard value, and the rolling speed is stabilized at 4.55 m / s.

[0055] S3. Steady-state rolling: The real-time monitoring value of the three-point difference ΔH = 0.06 mm, triggering a first-level response; Operate to increase the bending roll force to 902 kN (+10%), and the transmission side roll gap compensation is 0.3 mm; Increase the side cooling to 120%, and after 35 seconds, ΔH drops to 0.02 mm.

[0056] S4. Tail-off control: Reduce the speed to 3.5 m / s 50 meters in advance, and reduce the middle cooling water volume to 80%; The bending roll force steps down to 65% of the reference value, and the three-point difference at the tail is stabilized at 0.03 mm.

[0057] Verification of implementation effect Table 4 Comparison of implementation effects of Q235B

[0058] Example 2 65Mn 500×3.5 mm high-carbon tool steel S1. Preparation before rolling and parameter initialization: Steel grade characteristics: C: 0.62 - 0.70%, Mn: 0.90 - 1.20%.

[0059] Equipment configuration: Rolling mill stiffness: 6500 kN / mm (strengthened support); Cooling system: Nitrogen atomization cooling (oxidation inhibition).

[0060] Initial parameters:

[0061] S2. Dynamic adjustment during the threading stage: (speed ≤ 5 m / s) Thickness pre-compensation: Detect the leading end temperature of 825 °C (5 °C lower than the target), and compensate the roll gap by +0.15 mm; Reduce the side cooling water volume to 80% (flow rate 144 m 3 / h).

[0062] Bending roll force loading: The initial value is set to 90% of the reference value (OS 788 kN / DS 735 kN) and linearly increased to 100% within 8 seconds.

[0063] S3. Steady-state rolling control: (speed 7.5 m / s) Three-point difference regulation: Calculate ΔH = 0.08 mm (exceeding the limit) in real time, trigger a secondary response: operate the bending roll force +12% (to 1176 kN), the drive side roll gap compensation is 0.4 mm; the edge cooling water volume is increased to 130% (flow rate 234 m 3 / h), after 45 seconds, ΔH drops to 0.03 mm. Thermal crown compensation: Update the compensation amount every 20 pieces, and the roll gap is finely adjusted by +0.02 mm.

[0064] S4. Tail flicking and abnormal handling: Tail control: Decelerate to 3.8 m / s 50 meters in advance, and the middle cooling water volume is reduced to 80%; Abnormal response: When the rolling force fluctuation > 15%, insert 1 piece of gradually changing transition material (4.0 → 3.7 → 3.5 mm); when the warning of thickening scale appears, rapidly cool down.

[0065] Matters not covered by this invention are all well-known technologies.

[0066] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A dynamic adjustment method for three-point difference during the hot-rolled strip rolling process, characterized in that: The method includes the following steps: S1. Preparation before rolling and parameter initialization: roll profile matching, preloading of model parameters; S2. Dynamic regulation during threading: thickness pre-compensation, suppression of temperature gradient; S3. Steady-state rolling control: real-time monitoring and compensation of three-point difference, dynamic compensation of thermal crown; S4. Tail flick and abnormality handling: tail stability control, intelligent transition material insertion.

2. The dynamic adjustment method for the three-point difference during the hot-rolled strip rolling process according to claim 1, wherein: In the step S1, select the roll profile according to the production plan: when rolling at a high pace, the concavity is 0.12 - 0.15 mm to suppress the thermal crown; when rolling at a low pace, the concavity is 0.05 - 0.08 mm to reduce wear; when rolling the warm-up material after roll change: roll 5 - 8 transition materials, set the initial bending roll force to 80% of the reference value, and increase by 5% for each piece until full load.

3. A dynamic adjustment method for the three-point difference during the hot-rolled strip rolling process according to claim 1, characterized in that: In the step S1, the preloading of model parameters includes: calling the historical optimal parameters of the same specification from the digital twin platform; calibrating the detection instruments: the zero error of the laser thickness gauge is ≤ 0.005 mm, and the deviation of the infrared thermometer is ≤ ±3°C.

4. A method for dynamically adjusting the three-point difference during the hot rolling process of hot-rolled strip steel according to claim 1, characterized in that: In the step S2, the thickness pre-compensation includes: predicting the thickness deviation based on the head temperature, pre-adjusting the roll gap by 0.10 - 0.30 mm, where for every 10°C decrease in temperature, the roll gap compensation is +0.05 mm; the bending roll force starts at 90% of the reference value and linearly increases to 100% within 10 seconds.

5. A method for dynamically adjusting the three-point difference during the hot rolling process of hot-rolled strip steel according to claim 1, characterized in that: In the step S2, the suppression of temperature gradient includes: temporarily reducing the side cooling water volume to 80% of the standard value to reduce the temperature drop during threading; stabilizing the rolling speed within 30 m at the head at 4.50 - 4.60 m / s.

6. The dynamic adjustment method for the three-point difference during the hot-rolled strip rolling process according to claim 1, wherein: In the step S3, the real-time monitoring and compensation of three-point difference includes: Calculating the three-point difference: Among them, h L is the thickness on the operating side; hc is the middle thickness; h T is the thickness on the driving side; △H is the three-point difference; Hierarchical response: When ΔH is 0.05 - 0.08 mm, increase the operating side bending roll force by 6 - 10%; compensate the drive side reduction by 0.1 - 0.3 mm; increase the side cooling flow rate by 10 - 20%; When ΔH > 0.08 mm, increase the operating side bending roll force by 10 - 15%; compensate the drive side reduction by 0.3 - 0.5 mm; increase the side cooling flow rate by 20 - 30%.

7. A dynamic adjustment method for the three-point difference during the hot rolling process of hot-rolled strip steel according to claim 1, characterized in that: In the step S3, the dynamic compensation of thermal crown includes: updating the compensation amount every 18 - 22 pieces rolled: Among them, C h (t) is the hot crown compensation; t is the rolling time; v is the rolling speed; N is the cumulative number of rolled coils; Fine-tuning the roll gap through hydraulic AGC, with the compensation amount error ≤ ±0.01 mm.

8. A method for dynamically adjusting the three-point difference during the hot rolling process of hot-rolled strip steel according to claim 1, characterized in that: In the step S4, the tail stability control includes: reducing the rolling speed to 3.5 - 4.5 m / s 48 - 52 m in advance, reducing the middle cooling water volume to 80 - 90%; gradually reducing the bending roll force to 65 - 75% of the reference value to suppress the tail warping.

9. A dynamic adjustment method for the three-point difference during the hot-rolled strip rolling process according to claim 1, characterized in that: In the step S4, the intelligent transition material insertion includes: when the predicted abnormal duration > 5 minutes, insert 1 piece of gradually changing transition material, and compress the transition section length to 14 - 16 m.

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