Control method for quick calibration of hot rolling roller change
By optimizing the hot rolling roll changing calibration process, the cooling water and mill can be started in advance, the rolling speed can be increased, and dynamic leveling can be achieved. This solves the problem of wasted time in the hot rolling roll changing calibration process and improves production efficiency and equipment safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-29
- Publication Date
- 2026-04-07
AI Technical Summary
The hot rolling roll change calibration process has problems such as waiting time, conservative speed, and separation of leveling and pressing, which leads to serious losses of non-production time and affects production capacity and energy consumption.
By optimizing the calibration process sequence, executing operations in parallel, starting the cooling water and rolling mill in advance, increasing the rolling speed, and combining dynamic leveling and multi-level fast opening protection, fast and safe roll gap control is achieved.
It significantly shortens the single calibration time, reduces non-production time, improves equipment operating rate and capacity, reduces energy consumption, and ensures rolling accuracy and stability.
Smart Images
Figure CN121797759A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automated control technology for hot rolling mill production lines, specifically to a control method for rapid calibration of hot rolling roll changing. Background Technology
[0002] In the hot-rolled strip production process, work rolls need to be replaced frequently due to the high temperature, high pressure, and severe wear. After each roll change, a calibration process must be performed to establish reference parameters for the automated control system that match the physical condition of the new roll. This is a prerequisite for ensuring the thickness accuracy, strip shape quality, and equipment safety of subsequent rolling processes.
[0003] Traditional roll change calibration processes typically employ a sequential, step-by-step approach, which presents the following inherent problems: There is waiting time between process steps. For example, the cooling water for the work rolls is usually turned on only during the mill startup phase. The mill needs to wait for the leveling operation to be completed before it can start. These sequential operations result in overall time wastage.
[0004] The roll gap pressing speed setting during the calibration process was too conservative and failed to fully utilize the equipment design capabilities, resulting in a long pressing process.
[0005] The leveling operation (used to eliminate uneven loading on both sides of the mill) is separated from the rolling process. It usually requires stopping at a specific rolling force point (e.g., 1980 kN) for static leveling, and then continuing to roll to the target force value (e.g., 15000 kN) after leveling. This "stop-leveling-re-rolling" mode not only increases calibration time, but also fails to achieve continuous and precise control of the mill's horizontal state by only performing leveling at discrete points.
[0006] The safety protection logic and hydraulic system response are not adapted for the rapid calibration process, which poses a risk of rapid equipment depressurization due to incorrect parameter input, and the hydraulic system pressure fluctuation may be too large during rapid action.
[0007] For hot rolling lines that change rolls more than 150 times per month, the cumulative non-production time lost due to the above problems is considerable, directly affecting production capacity and energy consumption. Summary of the Invention
[0008] (a) Technical problems to be solved The technical problem to be solved by this invention is a control method for rapid calibration of hot rolling roll change. By optimizing and reorganizing the calibration process sequence, execution logic and control parameters, the calibration time of a single calibration is significantly shortened while ensuring calibration accuracy.
[0009] (II) Technical Solution To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a control method for rapid calibration of hot rolling roll changing, comprising the following steps: S1. Calibration start: Control the hydraulic cylinder to quickly open, unload and retract to the mechanical zero position, and simultaneously turn on the cooling water of the working roller. Record the position offset value to complete the zero position calibration of the hydraulic cylinder. S2. After the cylinder zero position calibration is completed, control the roller gap to press down to the first preset position; S3. With the roll gap stationary, the rolling force detection unit is zeroed and calibrated. S4. After the rolling force detection unit is cleared to zero, start the rolling mill and control the roll gap to continue to be pressed down; S5. During the continued reduction of the roll gap, monitor the rolling force: When the rolling force is less than the first preset threshold, the first pressing speed is used for pressing. When the rolling force reaches or exceeds the first preset threshold, the rolling force is switched to a second rolling speed lower than the first rolling speed until the rolling force reaches the second preset threshold. S6. After the rolling force reaches the second preset threshold, control the roll gap on both sides of the mill to level it so that the rolling force deviation on both sides is less than the preset deviation value. S7. After the leveling is completed, while continuing to press the roll gap down to the third preset rolling force, dynamic leveling with zero as the reference is performed simultaneously. S8. After the rolling force reaches the third preset rolling force, the roll gap zero position calibration is completed.
[0010] As an improvement, in step S1, the cooling water for the working roller is turned on when the calibration start command is issued.
[0011] As an improvement, in step S4, the rolling mill is started immediately after the rolling force detection unit is zeroed.
[0012] As an improvement, the first pressing speed is not less than 0.88 mm / s.
[0013] As an improvement, the first preset threshold is 500KN, and the second preset threshold is 1960KN.
[0014] As an improvement, the preset deviation value in step S6 is 245KN.
[0015] As an improvement, the third preset rolling force is 15000KN.
[0016] As an improvement, the method further includes executing multi-level fast-opening protection logic based on the monitored rolling force during the calibration process.
[0017] As an improvement, the method also includes automatically starting an additional hydraulic pump before calibration begins.
[0018] As an improvement, the first preset position in step S2 is 10mm; the initial roll gap target position when pressing begins in step S4 is 2mm.
[0019] (III) Beneficial Effects The advantages of this invention compared to the prior art are: (1) By reordering the timing and parallelizing the actions, the waiting time between each stage is directly reduced. For example, starting the cooling water in advance saves about 11 seconds, and starting the rolling mill in advance saves about 6 seconds.
[0020] (2) By increasing the pressing speed and expanding the rapid pressing zone, the roll gap travel time is significantly shortened. For example, optimizing the speed of the rapid section can save about 35 seconds.
[0021] (3) By changing static leveling to dynamic leveling, the intermediate pause is eliminated, and the leveling process is completely overlapped with the final pressing process, saving 10-20 seconds of pure leveling waiting time. The mill is leveled under more continuous stress, which theoretically helps to improve calibration accuracy and subsequent rolling stability.
[0022] (4) By introducing multi-stage quick-opening protection and hydraulic system pre-support, reliable safety and equipment protection are provided for the calibration process after speed increase. Attached Figure Description
[0023] Figure 1 This is a flowchart of a control method for rapid calibration of hot rolling roll changing according to the present invention. Detailed Implementation
[0024] The invention will now be described in further detail with reference to specific embodiments, but this should not be construed as limiting the scope of the subject matter of the invention to the following embodiments.
[0025] Example 1
[0026] like Figure 1 The above describes a hot rolling roll changing calibration control process. The original calibration process is detailed in the background section, and its core problems lie in the sequential steps, conservative speed, and separation of balancing and pressing. The optimized process provided in this embodiment is as follows, with optimizations based on comparisons: Calibration Start and Initialization: Once the conditions are met, a calibration start command is issued. Simultaneously, two operations are performed: first, the HGC hydraulic cylinders on both sides are quickly unloaded to the mechanical zero position and the offset value is recorded (completing the cylinder zero-position calibration); second, the working roller cooling water is immediately turned on. This is a more advanced process compared to the original procedure where the cooling water was only turned on upon receiving the subsequent "start" signal.
[0027] Initial speed-up pressing: After zero-position calibration is completed, the automatic roll gap position control (APC) is activated, with a target position of 10mm. During this process, the pressing speed is set to 0.88mm / s, replacing the original conservative 0.25mm / s.
[0028] Rolling force zeroing and mill start-up: After the roll gap reaches 10mm and comes to a standstill, the system zeroes the rolling force detection unit. Immediately after the zeroing operation is complete, a mill start-up and speed setting signal is sent, causing the main drive to start rotating. The original procedure required waiting for the roll gap to reach 1960KN and for leveling to be completed before starting the mill.
[0029] Speed control and dynamic leveling based on rolling force: After the mill starts, the roll gap continues to decrease by 2mm. The system monitors the rolling force in real time. When the rolling force is less than 500 kN, the roll gap is pressed down rapidly (0.88 mm / s).
[0030] When the rolling force is ≥500KN, the roll gap automatically switches to slow pressing.
[0031] When the rolling force reaches 1960KN, the system performs a leveling adjustment to ensure that the rolling force deviation on both sides is less than 245KN.
[0032] The next step was a core improvement: instead of stopping, dynamic leveling was performed simultaneously throughout the entire process of slowly increasing the rolling force from 1960 kN to 15000 kN. This dynamic leveling aimed to keep the rolling force deviation on both sides close to zero, continuously fine-tuning the roll gap on both sides to ensure that the mill remained level throughout the process of increasing stress.
[0033] Calibration Completion and Protection: After the rolling force reaches 15000KN and dynamic leveling stabilizes the deviation within the allowable range, the system completes the zero-position calibration of the roll gap. Eccentricity detection is then performed, and the roll gap is finally opened to a safe position of 5mm.
[0034] Throughout the calibration process, a multi-stage rolling force quick-opening protection program provides continuous monitoring. If the rolling force experiences an abnormal surge for any reason, the system will immediately trigger the hydraulic cylinder quick-opening to protect the equipment. Furthermore, before the calibration process begins, the control system automatically activates an additional hydraulic pump to handle the instantaneous flow demands that may arise from rapid rolling, ensuring stable system pressure.
[0035] Effect verification: After applying the above method to the 2250 hot rolling production line, statistics show that: (1) Turning on the cooling water in advance saves about 11 seconds.
[0036] (2) Starting the rolling mill in advance saves about 6 seconds.
[0037] (3) The increased pressing speed saves about 35 seconds.
[0038] (4) Dynamic leveling eliminates pauses and saves 10-20 seconds.
[0039] (5) The cumulative reduction in single calibration time is approximately 65-80 seconds. Based on the production line's average monthly roller changes exceeding 150 times, non-production time is significantly reduced, improving equipment utilization and capacity, and lowering auxiliary energy consumption. In practical use, Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. In short, if those skilled in the art are inspired by these claims and design similar structural methods and embodiments without departing from the inventive spirit of the present invention, they should all fall within the protection scope of the present invention.
Claims
1. A control method for rapid calibration of hot rolling roll changing, characterized in that, Includes the following steps: S1. Calibration start: Control the hydraulic cylinder to quickly open, unload and retract to the mechanical zero position, and simultaneously turn on the cooling water of the working roller. Record the position offset value to complete the zero position calibration of the hydraulic cylinder. S2. After the cylinder zero position calibration is completed, control the roller gap to press down to the first preset position; S3. With the roll gap stationary, the rolling force detection unit is zeroed and calibrated. S4. After the rolling force detection unit is cleared to zero, start the rolling mill and control the roll gap to continue to be pressed down; S5. During the continued reduction of the roll gap, monitor the rolling force: -When the rolling force is less than the first preset threshold, the first pressing speed is used for pressing; - When the rolling force reaches or exceeds the first preset threshold, switch to a second rolling speed lower than the first rolling speed for rolling until the rolling force reaches the second preset threshold; S6. After the rolling force reaches the second preset threshold, control the roll gap on both sides of the mill to level it so that the rolling force deviation on both sides is less than the preset deviation value. S7. After the leveling is completed, while continuing to press the roll gap down to the third preset rolling force, dynamic leveling with zero as the reference is performed simultaneously. S8. After the rolling force reaches the third preset rolling force, the roll gap zero position calibration is completed.
2. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, In step S1, the cooling water for the working roller is turned on when the calibration start command is issued.
3. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, In step S4, the rolling mill is started after the rolling force detection unit is zeroed.
4. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The first pressing speed is not less than 0.88 mm / s.
5. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The first preset threshold is 500KN, and the second preset threshold is 1960KN.
6. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The preset deviation value in step S6 is 245 kN.
7. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The third preset rolling force is 15000KN.
8. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The method also includes executing multi-level fast-opening protection logic based on the monitored rolling force during the calibration process.
9. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, The method also includes automatically starting an additional hydraulic pump before calibration begins.
10. The control method for rapid calibration of hot rolling roll changing according to claim 1, characterized in that, In step S2, the first preset position is 10mm; in step S4, the initial roll gap target position when pressing begins is 2mm.