Temper method, system, device, medium suitable for acid pickling line
By measuring the elongation rate in real time on the last stand of the pickling and rolling line and implementing closed-loop control, combined with rolling force and roll gap position compensation, the problem of low elongation rate in pickling and rolling line production was solved, and high-quality product production was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI BAOSIGHT SOFTWARE CO LTD
- Filing Date
- 2022-01-12
- Publication Date
- 2026-06-02
AI Technical Summary
The existing pickling and rolling lines have complex production processes and low elongation, making it impossible to produce high-quality products, especially in terms of product flatness, roughness, and yield plateau elimination.
The last stand is used as a leveling machine. The elongation rate is measured in real time by combining a laser velocimeter and a thickness gauge. Through closed-loop control of the elongation rate, and by using rolling force and roll gap position compensation, high-precision elongation rate control is achieved, which suppresses elongation rate fluctuations and improves product quality.
By controlling the elongation rate with high precision, the application functions of the pickling and rolling line have been broadened, and the surface quality and material properties of the products have been significantly improved. The elongation rate accuracy has reached ±1.5%.
Smart Images
Figure CN116460146B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cold rolling technology in the metallurgical industry, specifically to a leveling method, system, device, and medium suitable for pickling and rolling lines. Background Technology
[0002] A typical pickling and rolling line has the function of opening all the roll gaps in the mill section, allowing incoming material to undergo stretching, straightening, pickling, washing, and edge trimming, and then directly coiling it without rolling to produce the finished product. This production method is generally used when the order requires a relatively thick product, and the thickness is almost the same as the incoming material. However, because the steel coils produced in this way have not undergone rolling, they cannot meet the requirements for high-quality products in terms of flatness, roughness, and elimination of yield plateau.
[0003] A search revealed that patent document CN110756585A discloses a method for producing nickel-based alloys using a 20-roll reversible mill. This method utilizes a 20-roll reversible mill to produce cold-rolled nickel-based alloy products through a process of coiling, threading, cold rolling, annealing, and finishing. In the cold rolling step, the 20-roll reversible mill performs seven passes on the industrial nickel-based alloy. The reduction rate in each pass is controlled at 6%–11%, the rolling force at 200–250 Ton, and the rolling speed at 100–300 MPa. The tension is maintained constant throughout the rolling process. The target thickness is achieved in one pass. While this prior art can achieve the desired thickness, the process is complex and the elongation is low.
[0004] Therefore, there is an urgent need to develop and design a method and system that can improve elongation, simplify the process, and enhance product quality. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a leveling method, system, device, and medium suitable for pickling and rolling lines. This method utilizes the last stand of a continuous rolling mill as a leveling machine, develops a corresponding high-precision closed-loop control function based on elongation, and performs leveling treatment on the pickled strip to improve product mechanical properties, shape, eliminate yield plateaus, and enhance product quality.
[0006] A leveling method suitable for pickling lines according to the present invention includes the following steps:
[0007] Step S1: Calculate the actual elongation rate by using a laser velocimeter and a thickness gauge to measure the front and rear speeds and front and rear thicknesses of the final frame in real time.
[0008] Step S2: Perform closed-loop control of elongation rate based on the actual elongation rate measured in real time using rolling force as the adjustment amount;
[0009] Step S3: Compensate the rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration;
[0010] Step S4: Use the thickness deviation measured by the thickness gauge at the front of the frame for feedforward control to suppress elongation fluctuations.
[0011] Preferably, step S1 includes: calculating the elongation ε1 in real time using the speeds measured by laser velocimeters at the front and rear of the final frame.
[0012] ε1=(Vexit–Vent) / Vent*100%
[0013] Here, Vexit refers to the rack exit speed, and Vent refers to the rack inlet speed.
[0014] Preferably, step S1 further includes: after measuring the thickness using thickness gauges at the front and rear of the final frame, calculating the actual elongation ε2 by comparison.
[0015] ε2=(H–h) / h*100%
[0016] Where H refers to the strip thickness at the set point, and h refers to the thickness at that point after rolling.
[0017] Preferably, step S1 further includes: when the leveling speed is less than 100 mpm, measuring and calculating the elongation ε2 using a thickness gauge; and when the leveling speed is greater than 100 mpm, measuring and calculating the elongation ε1 using a laser velocimeter.
[0018] Preferably, in step S2, the elongation closed-loop control consists of three loops: the elongation loop, the rolling force loop, and the position loop, forming a cascade control.
[0019] Preferably, in step S3, based on the principle that for strip steel of the same specification and material, when the elongation remains stable and the tension remains constant, the higher the rolling speed of the leveling mill, the greater the rolling force required, compensation is made for the rolling force, and the compensation amount is:
[0020]
[0021] Among them, F v It is the rolling force feedforward control compensation value; f g It is a function generator for speed and compensation coefficient; W is the width of the steel coil; T is the thickness of the steel coil; K v This is the gain coefficient. Depending on whether the actual compensation effect of the rolling force on-site is under-compensation or over-compensation, this coefficient should be increased or decreased appropriately.
[0022] Preferably, the thickness deviation e in step S4 is:
[0023] e = H act –H ref
[0024] Among them, H ref H refers to the reference thickness of the incoming material. act This refers to the actual thickness of the strip steel measured by the thickness gauge at the machine frame entrance;
[0025] Calculate the roll gap position compensation based on the thickness deviation e:
[0026] ΔS=Ke*e*(1-ε)
[0027] Wherein, ΔS refers to the roll gap position compensation amount. When the deviation is positive, the direction of ΔS is the direction of the roll gap opening; Ke is the gain coefficient. Depending on whether the actual effect after position compensation is under-compensation or over-compensation, this coefficient should be increased or decreased appropriately; e is the deviation between the thickness of the incoming material directly below the roll gap and the reference thickness; ε is the set elongation rate.
[0028] A leveling system suitable for pickling lines, provided by the present invention, comprises:
[0029] Module M1: The actual elongation is calculated by using a laser velocimeter and a thickness gauge to measure the front and rear speeds and front and rear thicknesses of the final frame in real time.
[0030] Module M2: Uses rolling force as an adjustment amount to perform closed-loop control of elongation based on the actual elongation measured in real time;
[0031] Module M3: Compensates for rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration;
[0032] Module M4: Uses the thickness deviation measured by the thickness gauge at the front of the frame for feedforward control to suppress elongation fluctuations.
[0033] According to the present invention, a computer-readable storage medium storing a computer program is provided, wherein when the computer program is executed by a processor, it implements the steps of the above-described method.
[0034] According to the present invention, a leveling device suitable for a pickling line includes the above-described leveling system suitable for a pickling line or the above-described computer-readable storage medium storing a computer program.
[0035] Compared with the prior art, the present invention has the following beneficial effects:
[0036] 1. This invention expands the functionality of the pickling line by utilizing the last stand in the pickling and rolling mill to achieve high-precision closed-loop control of elongation leveling, and improves the surface quality and material properties of the products.
[0037] 2. The present invention has strong anti-interference ability and high reliability due to the real-time measurement method of actual elongation using a laser velocimeter and thickness gauge.
[0038] 3. This invention uses a cascade control consisting of an elongation loop, a rolling force loop, and a position loop, supplemented by acceleration and deceleration rolling force compensation control, and position feedforward control based on the fluctuation of the incoming material thickness difference. Ultimately, it achieves the leveling function based on elongation closed-loop control using the last stand on the pickling and rolling line, with an elongation accuracy of ±1.5%. Attached Figure Description
[0039] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0040] Figure 1 This is a flowchart illustrating the overall process steps of the leveling method applicable to pickling lines in this invention.
[0041] Figure 2 This is a schematic diagram of the thickness micro-tracking principle in this invention;
[0042] Figure 3 This is a schematic diagram of the elongation closed-loop control principle in this invention;
[0043] Figure 4 This is a schematic diagram illustrating the speed and rolling force compensation principle in this invention.
[0044] Figure 5 This is a schematic diagram of the feedforward control based on the fluctuation of incoming material thickness in this invention. Detailed Implementation
[0045] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0046] like Figure 1 As shown, the present invention provides a leveling method suitable for pickling lines, comprising the following steps:
[0047] Step S1: The actual elongation rate is calculated by using a laser velocimeter and a thickness gauge to measure the front and rear speeds and front and rear thicknesses of the final frame in real time. The actual elongation rate is calculated in real time using two methods: one based on the thickness gauge and the other based on the laser velocimeter.
[0048] (1) The elongation ε1 is calculated in real time using the speed measured by the laser velocimeters at the front and rear of the final frame:
[0049] ε1=(Vexit–Vent) / Vent*100%
[0050] Here, Vexit refers to the rack exit speed, and Vent refers to the rack inlet speed.
[0051] (2) After measuring the thickness using thickness gauges at the front and rear of the final frame, the actual elongation ε2 is obtained by comparison:
[0052] ε2=(H–h) / h*100%
[0053] Where H refers to the strip thickness at the set point, and h refers to the thickness at that point after rolling.
[0054] Since the thickness gauges at the front and rear of the frame are approximately 2500mm away, to find the corresponding rolled thickness h of the strip thickness H measured at a certain point on the frame inlet side, a tracking shift function is required. This necessitates the use of a queue data structure. The 2500mm distance from the inlet thickness gauge to the frame is divided into 125 equally spaced queues of 20mm intervals each (queue 1). The distance is accumulated by multiplying the frame inlet speed by the scanning time. Every 20mm accumulated, the thickness H advances one grid in the queue. After advancing 125 grids, the thickness H reaches directly below the frame. Similarly, the 2500mm distance from the frame to the outlet thickness gauge is divided into 125 equally spaced queues of 20mm intervals each (queue 2). The distance is accumulated by multiplying the frame outlet speed by the scanning time. Every 20mm accumulated, the thickness H advances one grid in the queue. After advancing 125 grids, the thickness H reaches directly below the frame outlet thickness gauge. The entire process is illustrated in the attached diagram. Figure 2 As shown in the figure. This allows us to find the original thickness H corresponding to the thickness h measured in real time by the outlet thickness gauge.
[0055] Based on the results of field application of the elongation rate measurement based on thickness measurement, the laser velocimeter showed little lag in its elongation rate measurement, but it was easily affected by emulsion interference at low speeds, leading to inaccurate measurements. The thickness gauge, on the other hand, provided high accuracy and strong resistance to dry emulsion interference. Therefore, the final actual elongation rate was a combination of both methods: when the leveling speed was below 100 mpm, the elongation rate ε2 was calculated using the thickness gauge; when the leveling speed was above 100 mpm, the elongation rate ε1 was calculated using the laser velocimeter. Considering that the thickness gauge often calibrates to obtain a more accurate absolute value of the elongation rate, to eliminate systematic errors in the velocimeter's results, the elongation rate measured by the thickness gauge was adaptively corrected to ensure that the absolute values of the two measurement methods were essentially consistent, guaranteeing a smooth transition during switching.
[0056] The adaptive correction method is as follows:
[0057]
[0058] ADP n =Z n *K adp+ADP n-1
[0059] In the above formula:
[0060] ε 测厚n The elongation was measured using a thickness gauge in the nth measurement.
[0061] ε 测速n The elongation was measured using a velocimeter for the nth time.
[0062] K adp : Adaptive correction rate
[0063] The final elongation measured by the velocimeter was (1+ADP) n Complete adaptive correction.
[0064] Step S2: The elongation is controlled in a closed-loop manner using rolling force as the adjustment variable based on the actual elongation measured in real-time. In the pickling line, the leveled material is generally thick, and the elongation control uses a constant tension mode with rolling force adjustment. The elongation closed-loop control employs a cascade control consisting of an elongation loop, a rolling force loop, and a position loop. Specifically, the elongation loop is a negative feedback control loop that performs a closed loop based on elongation. The input to the elongation control loop is the set elongation value, and the feedback is the actual elongation value measured by a speedometer or thickness gauge. The deviation between the two is passed through a PI controller. The output of the PI controller, plus the basic rolling force setting and the rolling force generated by acceleration / deceleration compensation, serves as the input for the rolling force loop.
[0065] The rolling force loop refers to a closed-loop negative feedback control loop based on the rolling force of the mill stand. The rolling force loop uses the output of the elongation loop PI controller plus the rolling force generated by the basic rolling force setting and acceleration / deceleration compensation as the setpoint, and the actual feedback value of the rolling force obtained from the rolling force gauge. The resulting deviation is passed through the PI controller. The output of the PI controller plus the roll gap position compensation generated by the thickness difference of the incoming material measured by the thickness gauge in front of the mill stand is used as the setpoint for the position loop.
[0066] The position loop refers to a closed-loop negative feedback control loop based on the position of the hydraulic cylinder. The position loop uses the output of the rolling force loop PI control plus the roll gap position compensation generated by the thickness difference of the incoming material measured by the thickness gauge in front of the stand as the position setpoint, and the position feedback is obtained from the magnetic scale built into the hydraulic cylinder. The deviation between the two is passed through the P controller and the output acts on the servo valve to complete the position control of the roll gap.
[0067] The above three-loop control system, from the outside in, consists of: elongation loop, rolling force loop, and position loop. The output of the outer loop serves as the reference for the inner loop, and they are connected in series to form a three-loop cascade control system. For example... Figure 3 As shown.
[0068] First, based on the needs of the production process, the operator provides the elongation setpoint, which is sent to the elongation controller. The elongation controller is a PI controller. Based on the deviation between the setpoint and the actual feedback value, the PI controller generates a rolling force correction amount, which is superimposed with the initial rolling force and the acceleration / deceleration compensation rolling force to generate the rolling force setpoint. The rolling force setpoint is then sent to the rolling force controller, which is also a PI controller. Based on the deviation between the setpoint and the actual feedback value, the PI controller generates a roll gap position adjustment amount. This adjustment amount is superimposed with the position compensation amount based on thickness difference feedforward and sent to the servo position controller. The servo position control system is a P controller. It controls the servo valve through the output, and through the hydraulic system, it completes the roll gap position adjustment, thereby adjusting the rolling force, ultimately allowing the elongation to reach the setpoint.
[0069] Step S3: Compensate for rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration. During acceleration and deceleration, changes in factors such as the friction coefficient can disturb the rolling force, leading to increased elongation fluctuations. Therefore, compensation is performed on the rolling force to eliminate these fluctuations. Based on the principle that for strips of the same specification and material, when maintaining stable elongation and constant tension, a higher leveling mill rolling speed requires a greater rolling force. The compensation amount is as follows:
[0070]
[0071] Among them, F v It is the rolling force feedforward control compensation value; f g It is a function generator for speed and compensation coefficient; W is the width of the steel coil; T is the thickness of the steel coil; K v The gain coefficient should be adjusted according to whether the actual effect of the on-site rolling force compensation is under-compensation or over-compensation, and should be increased or decreased accordingly.
[0072] Where the speed compensation coefficient f g This is a curve showing the measured speed and rolling force compensation values. Different steel grades correspond to different curves, and similar steel grades are grouped together. For each steel grade strip, during the leveling test, the strip width W and coil thickness T are recorded first. During the leveling process, the rolling force is measured at seven steady-state leveling speeds: 30mpm, 60mpm, 90mpm, 150mpm, 200mpm, 250mpm, and 300mpm, when the elongation meets the standard. Finally, the rolling force at 30mpm is taken as the zero point, and the difference between the rolling force at other speeds and the rolling force at 30mpm is taken as the rolling force compensation value at that speed. Then, the compensation value T / W at each speed is normalized. Finally, the FG function for piecewise interpolation is generated, as shown below. Figure 4 As shown.
[0073] Step S4: To address the issue that fluctuations in the thickness of hot-rolled incoming material can cause fluctuations in elongation, a feedforward control method was adopted, which uses the thickness deviation measured by the thickness gauge in front of the stand for feedforward control to suppress the fluctuations in elongation.
[0074] First, when switching the elongation control from non-input to input mode, the incoming material thickness is sampled 5 times with a period of 20ms using an inlet thickness gauge, and the average is taken to obtain the reference thickness H of the roll. ref The actual thickness H of the strip steel measured by the thickness gauge at the entrance of the frame is then determined. act Micro-tracking displacement is performed (the micro-tracking displacement method is the same as the micro-tracking displacement method in the above-mentioned elongation measurement method based on thickness gauge), until it reaches directly below the roll gap of the frame, and the thickness deviation e is:
[0075] e = H act –H ref
[0076] Among them, H ref H refers to the reference thickness of the incoming material. act This refers to the actual thickness of the strip steel measured by the thickness gauge at the machine frame entrance;
[0077] Calculate the roll gap position compensation based on the thickness deviation e:
[0078] ΔS=Ke*e*(1-ε)
[0079] Wherein, ΔS refers to the roll gap position compensation amount. When the deviation is positive, the direction of ΔS is the direction of the roll gap opening; Ke is the gain coefficient. Depending on whether the actual effect after position compensation is under-compensation or over-compensation, this coefficient should be increased or decreased appropriately; e is the deviation between the thickness of the incoming material directly below the roll gap and the reference thickness; ε is the set elongation rate.
[0080] Feedforward control based on incoming material thickness fluctuations, such as Figure 5 As shown, through the closed-loop feedback control, feedforward control, and compensation control described above, the leveling function based on elongation closed-loop control is finally completed on the last stand of the acid rolling line, and the elongation accuracy is ±1.5%.
[0081] The present invention also provides a leveling system suitable for pickling lines, comprising:
[0082] Module M1: The actual elongation is calculated by using a laser velocimeter and a thickness gauge to measure the front and rear speeds and front and rear thicknesses of the final frame in real time.
[0083] Module M2: Uses rolling force as an adjustment amount to perform closed-loop control of elongation based on the actual elongation measured in real time;
[0084] Module M3: Compensates for rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration;
[0085] Module M4: Uses the thickness deviation measured by the thickness gauge at the front of the frame for feedforward control to suppress elongation fluctuations.
[0086] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the above-described method.
[0087] The present invention further provides a leveling apparatus suitable for pickling lines, including the above-described leveling system suitable for pickling lines or the above-described computer-readable storage medium storing a computer program.
[0088] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.
[0089] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.
Claims
1. A leveling method suitable for pickling lines, characterized in that, Includes the following steps: Step S1: Calculate the actual elongation rate by using a laser velocimeter and a thickness gauge to measure the front and rear speeds and front and rear thicknesses of the final frame in real time. Step S2: Perform closed-loop control of elongation rate based on the actual elongation rate measured in real time using rolling force as the adjustment amount; Step S3: Compensate the rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration; Step S4: Use the thickness deviation measured by the thickness gauge at the front of the frame for feedforward control to suppress elongation fluctuations; The thickness deviation e in step S4 is: e = H act – H ref Among them, H ref H refers to the reference thickness of the incoming material. act This refers to the actual thickness of the strip steel measured by the thickness gauge at the machine frame entrance; Calculate the roll gap position compensation based on the thickness deviation e: in, This refers to the compensation amount for the roll gap position; when the deviation is positive... The direction is the direction of the roll gap; Ke is the gain coefficient, which should be increased or decreased appropriately depending on whether the actual effect of the position compensation on site is under-compensation or over-compensation. It tracks the deviation between the incoming material thickness and the reference thickness directly below the roll gap; It sets the elongation rate.
2. The leveling method for pickling lines according to claim 1, characterized in that, Step S1 includes: calculating the elongation in real time using the speeds measured by laser velocimeters at the front and rear of the final frame. 1: 1= (Vexit – Wind) / Wind * 100% Here, Vexit refers to the rack exit speed, and Vent refers to the rack inlet speed.
3. The leveling method for pickling lines according to claim 1, characterized in that, Step S1 further includes: after measuring the thickness using thickness gauges at the front and rear of the final frame, calculating the actual elongation by comparison. 2: 2= (H– h) / h * 100% Where H refers to the strip thickness at the set point, and h refers to the thickness at the set point after rolling.
4. The leveling method applicable to pickling lines according to claim 1, characterized in that, Step S1 further includes: when the leveling speed is less than 100 mpm, using a thickness gauge to measure and calculate the elongation. 2; When the leveling speed is higher than 100mpm, the elongation is calculated using a laser velocimeter.
1.
5. The leveling method for pickling lines according to claim 1, characterized in that, In step S2, the elongation closed-loop control consists of three loops: the elongation loop, the rolling force loop, and the position loop, forming a cascade control.
6. The leveling method applicable to pickling lines according to claim 1, characterized in that, In step S3, based on the principle that for strip steel of the same specification and material, when the elongation remains stable and the tension remains constant, the higher the rolling speed of the leveling mill, the greater the rolling force required. Therefore, the rolling force is compensated, and the compensation amount is: in, It is the rolling force feedforward control compensation value; It is a function generator for speed and compensation coefficient; It is the width of the steel coil; It refers to the thickness of the steel coil; It is the gain coefficient. Depending on whether the actual compensation effect of the rolling force on site is under-compensation or over-compensation, this coefficient can be increased or decreased.
7. A system for implementing the leveling method for a pickling line according to any one of claims 1-6, characterized in that, include: Module M1: The actual elongation is calculated by using a laser velocimeter and a thickness gauge to measure the inlet and outlet speeds and thicknesses of the frame in real time. Module M2: Uses rolling force as an adjustment amount to perform closed-loop control of elongation based on the actual elongation measured in real time; Module M3: Compensates for rolling force to eliminate elongation fluctuations caused by unit acceleration and deceleration; Module M4: Uses the thickness deviation measured by the thickness gauge at the front of the frame for feedforward control to suppress elongation fluctuations.
8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.
9. A leveling device suitable for pickling lines, characterized in that, This includes the leveling system for a pickling line as described in claim 7 or the computer-readable storage medium storing a computer program as described in claim 8.