Tension-temperature control system and method for six-roll reversible rolling mill for magnesium alloy strip

Abstract

The present application belongs to the technical field of six-roll reversible rolling mill control, specifically a tension-temperature control system and method for a six-roll reversible rolling mill for magnesium alloy strip, comprising: an intermediate roll transverse movement mechanism with a travel range of ±150mm and a displacement accuracy of ±0.01mm, for dynamically adjusting the contact arc length of the rolling zone; a temperature sensor array, integrated in the intermediate roll transverse movement guide rail, deployed in the 8-12mm gap between the working roll and the intermediate roll, comprising an 8-channel infrared temperature measurement unit with a wavelength of 3-5μm, a sampling frequency ≥1kHz, and a detection accuracy of ±2°C; a tension detection module with a range of 0-500kN, which outputs in real time the tension value F_corrected=F_raw×[1-0.0015(T_roll-25)] corrected for thermal expansion; a collaborative controller; the present application dynamically outputs high-precision tension set values ​​according to different rolling requirements and material properties through an intelligent tension management model, combines a dynamic tension measurement module to monitor the front and rear tensions of the rolling process in real time, and uses a tension control optimization module to compare the measured tension with the target value output by the model.

Description

Technical Field

[0001] The present application belongs to the technical field of six-roller reversible rolling mill control, and specifically relates to a six-roller reversible rolling mill tension-temperature control system and method for magnesium alloy strips. Background Art

[0002] Due to the low-temperature plasticity defects of the close-packed hexagonal crystal structure, the rolling of magnesium alloys needs to be strictly controlled within the warm rolling window of 300-400℃. However, traditional four-roll rolling mills are limited by insufficient roll system stiffness and a single degree of freedom in roll gap adjustment, resulting in rolling force fluctuations exceeding ±15%, lateral temperature differences of wide plates greater than ±25%, and ultra-thin strip breakage rates greater than 12%.

[0003] Although the six-high reversible rolling mill increases the roll system stiffness by 58% through the triple roll system structure and hydraulic lateral movement of the intermediate roll, it exposes structural contradictions in magnesium alloy rolling: First, the lateral movement function of the intermediate roll is only used to adjust the contact arc length and is not linked to the temperature field in the rolling zone. When the temperature drop rate of the plate edge reaches 3.8°C / s (2.3 times faster than that of the middle), the existing external preheating technology (such as CN114147066A) cannot use the axial movement of the intermediate roll to compensate for the heat conduction imbalance, resulting in a 40% increase in the crack initiation rate; second, Magnesium alloy deformation resistance decays exponentially with temperature, while the AGC system for six-high reversing mills (such as CN103521519A) still uses a PID algorithm with a fixed compensation coefficient. This lack of temperature feedback leads to a 9.6% strip breakage rate at rolling speeds greater than 60 m / min. Thirdly, while the high stiffness of the support rolls suppresses flexural deformation, it is not coordinated with the thermal crown changes of the intermediate rolls. When the roll body temperature difference is ±8°C, the traditional bending force compensation error reaches 18%, resulting in a transverse thickness deviation of >±0.03 mm for wide plates. Existing improvement proposals fail because they fail to fully integrate the structural characteristics of the six-high reversing mill. Asynchronous rolling ignores the potential for rebalancing the temperature field through the lateral movement of the intermediate rolls. Repeated annealing during multi-pass rolling causes grain coarsening and energy consumption greater than 320 kWh / t. Furthermore, segmented roll cooling technology is limited by the inter-roll clearance of the six-high reversing mill, resulting in a coverage efficiency of <55%. Therefore, it is urgent to develop a rolling control method that deeply integrates the structural characteristics of the six-roll reversible rolling mill and the temperature-sensitive characteristics of magnesium alloys, so as to break through bottlenecks such as temperature-tension coupling mismatch and lateral performance unevenness. Summary of the Invention

[0004] To achieve the above objectives, the present application provides the following technical solutions: an intermediate roller transverse movement mechanism with a travel range of ±150 mm and a displacement accuracy of ±0.01 mm, which is used to dynamically adjust the contact arc length of the rolling zone; the output end of the intermediate roller transverse movement mechanism is provided with a six-roll reversible mill intermediate roller, and the six-roll reversible mill intermediate roller is provided on both sides of the six-roll reversible mill backup roller and the six-roll reversible mill working roller respectively;

[0005] The temperature sensor array is integrated into the intermediate roll traverse mechanism and deployed in the 8-12mm gap between the work roll and the intermediate roll of the six-high reversing mill. It includes 8-channel infrared temperature measurement units with a wavelength of 3-5μm, a sampling frequency of ≥1kHz, and a detection accuracy of ±2°C.

[0006] Tension detection module, with a measuring range of 0-500kN, outputs the tension value corrected for thermal expansion in real time: F_corrected = F_raw × [1-0.0015(T_roll-25)];

[0007] A collaborative controller, the collaborative controller performing the following operations:

[0008] Generate dynamic tension thresholds F1=50-200kN, F2=30-180kN and the lateral displacement compensation amount ΔS=±5-20mm of the intermediate roll of the six-high reversible rolling mill based on the LSTM neural network;

[0009] When the measured tension deviation |F1′-(F1+ΔF)|>10%F1 or the transverse temperature difference>15°C, the intermediate roll of the six-roll reversible rolling mill is driven to move in a transverse step of ±5mm / °C and the bending force of the support roll is adjusted by ±5kN / °C;

[0010] The belt break protection protocol is triggered, the middle roll of the six-roll reversible rolling mill moves horizontally to the limit position of ±150mm, and the rolling speed drops to below 30m / min.

[0011] As an optimal technical solution of the present application, it also includes a roller conveyor, the collaborative controller is arranged on one side of the roller conveyor, and pinch rollers are provided on both sides of the roller conveyor, the outer surface of the pinch rollers is connected to the magnesium alloy strip for transmission, and coilers are symmetrically provided on both sides of the pinch rollers, the outer surface of the coiler is connected to the magnesium alloy strip for transmission, and a mounting frame is provided at the center axis of the roller conveyor, the two groups of the six-roller reversible rolling mill support rollers 205, the six-roller reversible rolling mill intermediate rollers 206 and the six-roller reversible rolling mill working rollers 207 are all located inside the mounting frame 203, the intermediate roller transverse movement mechanism is arranged inside the mounting frame, two tension detection modules are symmetrically provided on both sides of the roller conveyor, the tension detection module includes a bracket, the interior of the bracket is rotatably connected to the support shaft through a bearing, the outer surface of the support shaft is provided with a tension detection module, and a threaded hole is provided at the bottom of the bracket, and the bottom of the threaded hole is threadedly connected to the top of the roller conveyor.

[0012] As a preferred technical solution of the present application, the lateral resolution of the temperature sensor array is ≤1mm, and the density of the temperature measurement channels at the edge is 2 times higher than that in the middle. The infrared temperature measurement unit is linked with the intermediate roller transverse movement mechanism. When the transverse movement amount ΔS of the intermediate roller of the six-roll reversible rolling mill is greater than 50mm, it automatically switches to the edge priority temperature measurement mode.

[0013] As an optimal technical solution of this application, the collaborative controller includes a multi-objective optimization engine, which uses the NSGA-II algorithm to balance the following parameters: tension fluctuation rate <3%; lateral temperature difference <8°C; the matching relationship between the lateral movement speed of the intermediate roller of the six-roll reversible rolling mill and the rolling speed: v_lateral movement = 0.3v_rolling mill ± 0.05m / s.

[0014] As a preferred technical solution of the present application, the intermediate roll traverse mechanism and the bending roll system of the six-roll reversible rolling mill support roll 205 are dynamically coupled through a stiffness matrix. The stiffness matrix expression is:

[0015] GPa / mm

[0016] Among them, K[1.1], K[2,2], and K[3,3] correspond to the axial stiffness coefficients of the support roll, intermediate roll, and working roll of the six-high reversing mill, respectively.

[0017] As an optimal technical solution of this application, a temperature-tension-roller displacement joint compensation model is proposed based on the system:

[0018] ΔF=0.15×(T_act-T_set)×F0+0.02ΔS

[0019] Wherein, ΔS is the transverse displacement of the intermediate roller (206) of the six-roll reversible rolling mill, F0 is the reference tension, T_act and T_set are the workpiece temperature and the rolling temperature, respectively.

[0020] A method for controlling tension and temperature of a six-roll reversible rolling mill for magnesium alloy strips, applied to the aforementioned six-roll reversible rolling mill tension and temperature control system for magnesium alloy strips, comprises the following steps:

[0021] Obtain roll system parameters of a six-high reversible rolling mill: the diameter ratio of the six-high reversible rolling mill's backup roll: the six-high reversible rolling mill's intermediate roll: the six-high reversible rolling mill's working roll is 3.2:1.8:1, and the six-high reversible rolling mill's intermediate roll traverse stroke is ±150 mm;

[0022] Based on the rolling temperature T_set = 300-400℃ and the temperature gradient of the yield strength of the magnesium alloy, the temperature compensation tension deviation ΔF = 0.15 × (T_act-T_set) × F0 is calculated, where F0 = 120 kN;

[0023] When ΔF>20%F0, the lateral displacement compensation of the intermediate roll of the six-high reversible rolling mill is performed: ΔS=10mm×(ΔF / 20%), and the bending force of the support roll of the six-high reversible rolling mill is synchronously corrected ΔF_bend=50kN×(ΔS / 10mm).

[0024] As a preferred technical solution of the present application, the intermediate roller lateral displacement compensation includes direction selection logic:

[0025] When T_act>T_set, the middle roll of the six-roll reversible rolling mill moves laterally toward the operating side;

[0026] When T_act<T_set, the middle roller of the six-roller reversible rolling mill moves laterally toward the transmission side;

[0027] The traverse speed v=0.2×|T_act-T_set|mm / s, and the maximum does not exceed 20mm / s.

[0028] As a preferred technical solution of the present application, the bending force correction value ΔF_bend of the support roll of the six-high reversible rolling mill and the lateral displacement ΔS of the intermediate roll of the six-high reversible rolling mill meet the constraint conditions:

[0029] ΔF_bend 0.1× ×ΔS

[0030] in, =1250mm is the diameter of the support roller (205) of the six-roller reversible rolling mill, =680mm is the diameter of the middle roller (206) of the six-roller reversible rolling mill.

[0031] As a preferred technical solution of the present application, when the temperature of the rolled piece T_act>350°C and lasts for 3 seconds, execute:

[0032] The middle roll of the six-roll reversible rolling mill moves horizontally to the limit position of +150mm;

[0033] The bending force of the support rolls of the six-high reversible rolling mill is increased to 25MPa;

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] This application uses an intelligent tension management model to dynamically output high-precision tension setting values ​​for different rolling requirements and material properties, and combines the dynamic tension measurement module to monitor the front and rear tensions of the rolling process in real time. The tension control optimization module compares the measured tension with the target value output by the model. When it is detected that the deviation exceeds the allowable threshold, the closed-loop adjustment mechanism is immediately triggered. By real-time correction of the uncoiler torque, rolling mill speed and coil diameter compensation coefficient of the coiler, the tension fluctuation rate is controlled within 3%. It effectively solves the problems of edge cracking, thickness tolerance and high strip breakage rate of magnesium alloy plates caused by uneven tension, and increases the rolling yield of magnesium alloy from 75% of the traditional process to more than 92%. At the same time, it is compatible with the precision rolling of metal plates such as aluminum and copper, significantly improving the real-time, adaptability and process stability of the tension control of the six-roll reversible rolling mill, increasing the unit production capacity by 30%, and reducing the overall production cost by 18%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of a method for a six-roll reversible mill tension-temperature control system for magnesium alloy strip;

[0037] Figure 2 This is a schematic diagram of a six-roll reversible rolling mill tension-temperature control device for magnesium alloy strips provided in this application;

[0038] Figure 3 This is the structure diagram of the tension detection module equipment provided by this application.

[0039] Explanation of the accompanying symbols: 1. Bracket; 2. Through-axis tension sensor; 3. Bearing; 4. Support shaft; 5. Threaded hole; 201. Magnesium alloy strip; 202. Coiler; 203. Mounting frame; 204. Tension detection module; 205. Support roller of six-roll reversible rolling mill; 206. Intermediate roller of six-roll reversible rolling mill; 207. Working roller of six-roll reversible rolling mill; 208. Roller table; 209. Pinch roller. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0041] Example 1:

[0042] like Figure 1-2As shown, the present application provides a method for controlling tension when rolling magnesium alloys on a six-roll reversible mill. This method solves the existing problems of inaccurate tension control when rolling magnesium alloys on a six-roll reversible mill, which can lead to edge cracking and strip breakage. This tension control method can improve the accuracy and stability of tension control on the six-roll reversible mill, thereby increasing the yield rate and production efficiency of magnesium alloys rolled on the six-roll reversible mill.

[0043] A six-roller reversible rolling mill tension-temperature control system for magnesium alloy strips, comprising:

[0044] The intermediate roller transverse movement mechanism has a travel range of ±150mm and a displacement accuracy of ±0.01mm. It is used to dynamically adjust the contact arc length of the rolling zone. The output end of the intermediate roller transverse movement mechanism is provided with a six-roll reversible mill intermediate roller 206. The six-roll reversible mill intermediate roller 206 is provided on both sides with a six-roll reversible mill support roller 205 and a six-roll reversible mill working roller 207.

[0045] The temperature sensor array is integrated into the intermediate roll traverse guide rail and deployed in the 8-12mm gap between the work roll and the intermediate roll. It includes 8-channel infrared temperature measurement units with a wavelength of 3-5μm, a sampling frequency of ≥1kHz, and a detection accuracy of ±2°C.

[0046] Tension detection module (204), with a measuring range of 0-500 kN, outputs in real time a tension value F_corrected=F_raw×[1-0.0015(T_roll-25)] corrected for thermal expansion;

[0047] Co-controllers, which do the following:

[0048] Generate dynamic tension thresholds F1=50-200kN, F2=30-180kN and intermediate roller lateral displacement compensation ΔS=±5-20mm based on LSTM neural network;

[0049] When the measured tension deviation |F1′-(F1+ΔF)|>10%F1 or the transverse temperature difference>15℃, drive the intermediate roller to move in steps of ±5mm / ℃ and adjust the support roller bending force by ±5kN / ℃;

[0050] Triggering the belt break protection protocol: the middle roller moves horizontally to the ±150mm limit position, and the rolling speed drops below 30m / min.

[0051] It also includes a roller table 208, a collaborative controller is arranged on one side of the roller table 208, and pinch rollers 209 are arranged on both sides of the roller table 208. The outer surface of the pinch roller 209 is connected to the magnesium alloy strip 201, and the magnesium alloy strip 201 is transmitted above the pinch roller 209 and the roller table 208. Coilers 202 are symmetrically arranged on both sides of the pinch roller 209, and the outer surface of the coiler 202 is connected to the magnesium alloy strip 201 for transmission. The coiler 202 is started and drives the magnesium alloy strip 201 to be transmitted. A mounting frame 203 is provided at the central axis of the roller table 208, and two sets of six-roller reversible rolling mill support rollers 205, six-roller reversible rolling mill intermediate rollers 206 and six-roller reversible rolling mill working rollers 207 are all located inside the mounting frame 203. The frame 203 installs and fixes the support roller 205, the intermediate roller 206 and the working roller 207 of the six-roll reversible rolling mill. The intermediate transverse movement mechanism is arranged inside the mounting frame 203, and the intermediate roller transverse movement mechanism adjusts the position of the intermediate roller 206 of the six-roll reversible rolling mill. Two tension detection modules 204 are symmetrically provided on both sides of the roller table 208. The tension detection module 204 performs tension detection on the magnesium alloy strip 201. The tension detection module 204 includes a bracket 1. The interior of the bracket 1 is rotatably connected to the support shaft 4 through the bearing 3. The outer surface of the support shaft 4 is provided with a tension detection module. A threaded hole 5 is provided at the bottom of the bracket 1. The bottom of the threaded hole 5 is threadedly connected to the top of the roller table 208.

[0052] The lateral resolution of the temperature sensor array is ≤1mm, and the density of temperature measurement channels at the edge is 2 times higher than that in the middle. The infrared temperature measurement unit is linked to the intermediate roller transverse movement mechanism. When the transverse movement ΔS of the intermediate roller 206 of the six-roll reversible rolling mill is greater than 50mm, it automatically switches to the edge priority temperature measurement mode.

[0053] The collaborative controller includes a multi-objective optimization engine and uses the NSGA-II algorithm to balance the following parameters: tension fluctuation rate <3%; lateral temperature difference <8°C; and the matching relationship between the lateral speed of the middle roll 206 of the six-high reversing rolling mill and the rolling speed: v_lateral = 0.3v_rolling mill ± 0.05m / s.

[0054] The intermediate roll traverse mechanism and the bending roll system of the six-roll reversible mill support roll 205 are dynamically coupled through the stiffness matrix. The stiffness matrix expression is:

[0055] GPa / mm

[0056] Among them, K[1.1], K[2,2], K[3,3] correspond to the axial stiffness coefficients of the six-high reversible rolling mill support roll 205, the six-high reversible rolling mill intermediate roll 206 and the six-high reversible rolling mill working roll 207 respectively.

[0057] Based on the system, a temperature-tension-roller displacement joint compensation model is proposed:

[0058] ΔF=0.15×(T_act-T_set)×F0+0.02ΔS

[0059] Wherein, ΔS is the transverse displacement of the intermediate roller (206) of the six-roll reversible rolling mill, F0 is the reference tension, T_act and T_set are the workpiece temperature and the rolling temperature, respectively.

[0060] A method for controlling tension and temperature of a six-roll reversible rolling mill for magnesium alloy strips, which is applied to a tension and temperature control system of a six-roll reversible rolling mill for magnesium alloy strips, comprises the following steps:

[0061] Obtain the roll system parameters of the six-high reversible rolling mill: the diameter ratio of the six-high reversible rolling mill support roll 205: the six-high reversible rolling mill intermediate roll 206: the six-high reversible rolling mill working roll 207 is 3.2:1.8:1, and the traverse stroke of the six-high reversible rolling mill intermediate roll 206 is ±150 mm;

[0062] Based on the rolling temperature T_set = 300-400℃ and the temperature gradient of the yield strength of the magnesium alloy Δσ_s / ΔT = -0.38MPa / ℃, the temperature compensation tension deviation ΔF = 0.15×(T_act-T_set)×F0 is calculated, where F0 = 120kN;

[0063] When ΔF>20%F0, the lateral displacement compensation of the intermediate roller 206 of the six-high reversible rolling mill is performed: ΔS=10mm×(ΔF / 20%), and the bending force of the support roller 205 of the six-high reversible rolling mill is synchronously corrected ΔF_bend=50kN×(ΔS / 10mm).

[0064] Intermediate roller lateral displacement compensation includes direction selection logic:

[0065] When T_act>T_set, the middle roll 206 of the six-high reversible rolling mill moves laterally toward the operating side;

[0066] When T_act<T_set, the middle roller 206 of the six-high reversible rolling mill moves laterally toward the transmission side;

[0067] The traverse speed v=0.2×|T_act-T_set|mm / s, and the maximum does not exceed 20mm / s.

[0068] The bending force correction value ΔF_bend of the support roll 205 of the six-high reversible rolling mill and the lateral displacement ΔS of the intermediate roll 206 of the six-high reversible rolling mill meet the constraint conditions:

[0069] ΔF_bend 0.1× ×ΔS

[0070] in, =1250mm is the diameter of the support roller (205) of the six-roller reversible rolling mill, =680mm is the diameter of the middle roller (206) of the six-roller reversible rolling mill.

[0071] The method also includes a strip break suppression strategy: when the rolled piece temperature T_act> 350°C and lasts for 3 seconds, execute:

[0072] The middle roll 206 of the six-high reversible rolling mill moves horizontally to the limit position of +150mm;

[0073] The bending force of the support roll 205 of the six-high reversible rolling mill is increased to 25MPa;

[0074] The main drive motor of the rolling mill is decelerated to below 30m / min within 3 seconds, and the deceleration acceleration is ≥2m / s².

[0075] First, this application addresses the conflict between the structural characteristics and temperature sensitivity of six-high reversing mills used in magnesium alloy rolling by proposing a control method that integrates dynamic roll adjustment and intelligent compensation. First, based on the unique triple roll system parameters of the six-high reversing mill, a rolling force-temperature-roll gap coupling model is constructed. The magnesium alloy material parameters and rolling process are input, and the front / rear tension thresholds and the intermediate roll lateral compensation value ΔS are dynamically output through an LSTM neural network.

[0076] During the real-time control stage, a dedicated sensing solution for the six-roll reversible mill is adopted: a piezoelectric tension meter is installed on the intermediate roll transverse guide rail to eliminate the roll thermal expansion error; a miniature infrared array is embedded in the 8mm gap between the six-roll reversible mill working roll 207 and the six-roll reversible mill intermediate roll 206 to monitor the lateral temperature distribution of the rolled piece at a frequency of 1kHz.

[0077] When it is detected that the tension deviation exceeds the limit or the lateral temperature difference is greater than 15°C, the coordinated adjustment logic of the six-roll reversible rolling mill is triggered: when the front tension is insufficient, the torque of the uncoiler is increased by 5%-8% and the intermediate roller 206 of the six-roll reversible rolling mill is driven to move laterally +10mm to the operating side, compensating for the temperature drop at the edge by shortening the heat conduction path; when the rear tension exceeds the limit, the coil diameter compensation coefficient α=1+0.02ΔT is increased, and the bending force of the support roller is linked to reduce by 8%-12%, suppressing the thermal stress concentration caused by the high-rigidity support roller of the six-roll reversible rolling mill.

[0078] This method compresses the tension fluctuation rate to within 3% and controls the lateral thickness deviation to ±0.008mm through real-time coupling of the lateral displacement ΔS of the intermediate roller 206 of the six-roll reversible rolling mill and the temperature compensation coefficient K_T, which is a 60% improvement over the traditional four-roll rolling mill solution.

[0079] Secondly, this application designs a tension control system that is deeply bound to the structure of a six-roll reversible rolling mill, which includes three core modules: a structural adaptation controller: integrating the intermediate roll lateral movement mechanism and the support roll bending hydraulic station, and calculating the roll gap thermal deformation compensation in real time through the stiffness matrix model; a temperature sensor array: deploying an 8-channel infrared temperature measurement array and a fiber Bragg grating tension meter between the rolls of the six-roll reversible rolling mill, and optimizing the coordination between the lateral movement speed of the intermediate roll 206 of the six-roll reversible rolling mill and the main drive frequency converter of the rolling mill based on the NSGA-II multi-objective algorithm. Relationship, generate dynamic control instruction set such as ΔS=5mm / 10℃ temperature difference, bending roll force correction ±5kN / ℃; strip break suppression module: when the rolled piece temperature is greater than 350℃ or the tension deviation is greater than 20%, activate the exclusive protection protocol of the six-roll reversible rolling mill: the intermediate roll 206 of the six-roll reversible rolling mill moves horizontally to the limit position of +150mm to disperse thermal stress, and the bending roll force of the support roll 205 of the six-roll reversible rolling mill is increased to 25MPa to compensate for roll deflection. At the same time, the main drive motor of the rolling mill relies on its high inertia characteristics to stop at 30m / min within 3s.

[0080] Through the deep coupling of the mechanical characteristics and control logic of the six-high reversible rolling mill, the system achieves the following: (1) the utilization rate of the lateral movement function of the intermediate roll 206 of the six-high reversible rolling mill is increased from 60% to 98%, and the lateral temperature difference in the rolling zone is compressed from ±25℃ to ±6℃; (2) the strip breakage rate is reduced from 12% to 0.8%, and the yield rate exceeds 93%; (3) the upper limit of the rolling speed is increased from 60m / min to 90m / min, and the qualified rate of ultra-thin strip rolling is improved to 95%.

[0081] This application uses an intelligent tension management model to dynamically output high-precision tension setting values ​​for different rolling requirements and material properties, and combines the dynamic tension measurement module to monitor the front and rear tensions of the rolling process in real time. The tension control optimization module compares the measured tension with the target value output by the model. When it is detected that the deviation exceeds the allowable threshold, the closed-loop adjustment mechanism is immediately triggered. By real-time correction of the uncoiler torque, rolling mill speed and coil diameter compensation coefficient of the coiler, the tension fluctuation rate is controlled within 3%. It effectively solves the problems of edge cracking, thickness tolerance and high strip breakage rate of magnesium alloy plates caused by uneven tension, and increases the rolling yield of magnesium alloy from 75% of the traditional process to more than 92%. At the same time, it is compatible with the precision rolling of metal plates such as aluminum and copper, significantly improving the real-time, adaptability and process stability of the tension control of the six-roll reversible rolling mill, increasing the unit production capacity by 30%, and reducing the overall production cost by 18%.

[0082] Example 2: Suppression of edge cracks in wide magnesium alloy plates.

[0083] This embodiment is aimed at rolling AZ31 magnesium alloy plates with a width of 1500mm. Based on the lateral movement function of the six-roll reversible mill intermediate roll 206 and the high rigidity of the six-roll reversible mill support roll 205, the following scheme is implemented: a triple roll system of six-roll reversible mill support roll 205 Φ1250mm / six-roll reversible mill intermediate roll 206 Φ680mm / six-roll reversible mill working roll 207 Φ420mm is adopted, and the intermediate roll lateral movement mechanism is arranged The installation accuracy is ±0.01mm. 16 sets of infrared temperature measuring probes are symmetrically arranged at the transverse ends of the intermediate rolls 206 of the six-high reversible rolling mill on the operating and transmission sides of the rolling mill to capture the edge temperature drop gradient in real time. When the temperature difference ΔT between the edge and the middle is greater than 15°C, the intermediate rolls 206 of the six-high reversible rolling mill are controlled to transversely move toward the high-temperature side, and the bending force of the support rolls 205 of the six-high reversible rolling mill on that side is simultaneously reduced to compensate for the imbalance in rolling force distribution caused by transverse movement. Based on the roll gap model of the six-high reversible rolling mill:

[0084] ΔF=0.15×(T_act-T_set)×F0+0.02ΔS

[0085] The optimal solution set of the lateral displacement ΔS and the bending roll force correction was calculated, and multi-objective optimization of edge temperature uniformity and plate flatness was achieved through the NSGA-II algorithm. During the rolling process, the edge temperature drop rate was reduced from 3.8℃ / s to 0.9℃ / s, the lateral temperature difference was compressed from ±25℃ to ±5℃, the edge crack incidence rate was reduced from 18% to 0.3%, and the yield rate was increased to 96.5%. At the same time, the deflection deformation of the support roll was stabilized within 0.008mm / m.

[0086] Example 3: High-precision rolling of ultra-thin magnesium strip.

[0087] This embodiment realizes stable rolling of 0.08mm thick AZ61 magnesium strip on a six-roll reversible rolling mill, specifically including: reducing the diameter of the working roll 207 of the six-roll reversible rolling mill to Φ380mm, setting the lateral stroke of the intermediate roll 206 of the six-roll reversible rolling mill to +100mm, and reducing the rolling force by 28%; integrating a high-frequency piezoelectric tensiometer on the slider of the intermediate roll lateral mechanism, and combining it with a temperature compensation algorithm to eliminate thermal expansion errors; according to the axial temperature distribution of the support roll 205 of the six-roll reversible rolling mill, an 8-channel thermoelectric tensiometer is used. The system measures the strip with an accuracy of ±1°C, dynamically calculates the bending roll force correction value ΔF_bend = 12kN / °C, and adjusts it in real time through the hydraulic servo system. When the strip temperature is greater than 360°C or the tension fluctuation rate is greater than 8%, the exclusive protection mechanism of the six-roll reversible mill is triggered: the intermediate roll 206 of the six-roll reversible mill moves horizontally to the limit position of +150mm, the coolant flow of the working roll 207 of the six-roll reversible mill is increased to 200L / min, and the main drive motor of the mill slows down to 15m / min within 2.5s.

[0088] The thickness tolerance of the finished product is controlled within ±0.005mm, the strip breakage rate is reduced from 12% to 0.2%, the rolling speed is increased to 85m / min, and the grain size uniformity reaches ASTM grade 12.

[0089] Example 4: Temperature drop compensation during high-speed reversible rolling.

[0090] This embodiment solves the problem of uncontrolled temperature drop in a six-high reversible mill during 90 m / min high-speed reversible rolling. The key technologies include: arranging 24 sets of micro infrared sensors at the mill entrance and exit to establish a temperature prediction model for forward and reverse rolling; setting the lateral displacement of the intermediate roll 206 of the six-high reversible mill to +80 mm during forward rolling and -50 mm during reverse rolling, with a lateral displacement switching time of less than 1.5 s; constructing a dynamic tension compensation equation based on the real-time temperature drop rate: ΔF = 0.12v·(T _set-T_act), where v is the rolling speed, and the compensation amount is executed by the coiler servo hydraulic cylinder; during each reversal, the bending force of the support roll 205 of the six-high reversible rolling mill is reset to ±10% of the reference value, and the spray angle of the working roll is automatically adjusted by ±5° according to the lateral displacement. During high-speed rolling, the temperature drop rate is reduced from 50℃ / min to 12℃ / min, the tension fluctuation rate is stabilized within 1.8%, and the unit production capacity is increased by 45%. At the same time, the thickness transition section length of the reversing rolling is shortened from 10m to 0.8m.

[0091] Example 5: Adaptive rolling of multi-specification magnesium alloys

[0092] This embodiment realizes the rapid specification change rolling of different magnesium alloys such as AZ31 / AZ91. The core technology is: pre-storing the rheological stress-temperature curve and recrystallization temperature range of each grade of magnesium alloy; after inputting the target alloy grade, the system automatically loads the corresponding roll gap control parameters: AZ31 matches the lateral displacement of the intermediate roll 206 of the six-roll reversible rolling mill ΔS=±10mm / pass, and AZ91 adopts ΔS=±15mm / pass; based on the LSTM neural network, the thermal expansion of the rolling mill is predicted, and the bending force correction coefficient K_bend of the support roll 205 of the six-roll reversible rolling mill is output; the intermediate roll lateral displacement mechanism is preset with 10 process positions, and the lateral displacement is completed within 3 minutes through the servo motor drive. During specification change production, the thickness transition section is shortened from 15m to 1.2m, the yield rate is increased to 94.5%, the grain size difference between different alloys is controlled within 0.8μm, and the unit energy consumption is reduced by 28%.

[0093] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0094] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is limited by the appended claims and their equivalents.

Claims

1. A six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip, characterized in that: include: An intermediate roller transverse movement mechanism has a travel range of ±150 mm and a displacement accuracy of ±0.01 mm, and is used to dynamically adjust the contact arc length of the rolling zone. The output end of the intermediate roller transverse movement mechanism is provided with a six-roller reversible rolling mill intermediate roller (206), and the six-roller reversible rolling mill intermediate roller (206) is provided with a six-roller reversible rolling mill support roller (205) and a six-roller reversible rolling mill working roller (207) on both sides thereof. The temperature sensor array is integrated in the intermediate roller transverse mechanism and is deployed in the 8-12 mm gap between the working roller (207) and the intermediate roller (206) of the six-roll reversible rolling mill, and includes an 8-channel infrared temperature measurement unit with a wavelength of 3-5 μm, a sampling frequency of ≥1 kHz, and a detection accuracy of ±2°C; Tension detection module (204), with a measuring range of 0-500 kN, outputs in real time a tension value F_corrected=F_raw×[1-0.0015(T_roll-25)] corrected for thermal expansion; A collaborative controller, the collaborative controller performing the following operations: Generate dynamic tension thresholds F1=50-200 kN, F2=30-180 kN and a lateral displacement compensation amount ΔS=±5-20 mm of the intermediate roller (206) of the six-roller reversible rolling mill based on an LSTM neural network; When the measured tension deviation |F1′-(F1+ΔF)|>10%F1 or the transverse temperature difference>15°C, the intermediate roller (206) of the six-roller reversible rolling mill is driven to move transversely by a step length of ±5mm / °C and the bending force of the support roller is adjusted by ±5kN / °C; The broken belt protection protocol is triggered, and the intermediate roller (206) of the six-roller reversible rolling mill is moved horizontally to the limit position of ±150mm, and the rolling speed is reduced to below 30m / min. Specifically, when the temperature of the rolled piece T_act>350℃ and lasts for 3 seconds, the intermediate roller (206) of the six-roller reversible rolling mill is moved horizontally to the limit position of +150mm, the bending roll force of the support roller (205) of the six-roller reversible rolling mill is increased to 25MPa, and the main drive motor of the rolling mill is reduced to below 30m / min within 3 seconds, and the deceleration acceleration is ≥2m / s².

2. The six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 1, characterized in that: The invention also includes a roller conveyor (208), wherein the collaborative controller is arranged on one side of the roller conveyor (208), and pinch rollers (209) are arranged on both sides of the roller conveyor (208), and the outer surfaces of the pinch rollers (209) are connected to the magnesium alloy strip (201) for transmission, and coilers (202) are symmetrically arranged on both sides of the pinch rollers (209), and the outer surfaces of the coilers (202) are connected to the magnesium alloy strip (201) for transmission, and a mounting frame (203) is arranged at the center axis of the roller conveyor (208), and two groups of the six-roller reversible rolling mill support rollers (205), the six-roller reversible rolling mill intermediate rollers (206) and the six-roller reversible rolling mill intermediate rollers (207) are connected to the six-roller reversible rolling mill intermediate rollers (208). The roller (206), the intermediate roller transverse movement mechanism and the six-roller reversible rolling mill working roller (207) are all located inside the mounting frame (203). Two tension detection modules (204) are symmetrically provided on both sides of the roller table (208). The tension detection module (204) includes a bracket (1). The bracket (1) is rotatably connected to a support shaft (4) through a bearing (3). The outer surface of the support shaft (4) is provided with a tension detection module. A threaded hole (5) is provided at the bottom of the bracket (1). The bottom of the threaded hole (5) is threadedly connected to the top of the roller table (208).

3. The six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 2, characterized in that: The lateral resolution of the temperature sensor array is ≤1 mm, and the density of the temperature measurement channels at the edge is 2 times higher than that at the middle. The infrared temperature measurement unit is linked to the intermediate roller transverse movement mechanism. When the transverse movement amount ΔS of the intermediate roller (206) of the six-roller reversible rolling mill is greater than 50 mm, the system automatically switches to the edge priority temperature measurement mode.

4. The six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 2, characterized in that: The collaborative controller includes a multi-objective optimization engine and uses the NSGA-II algorithm to balance the following parameters: tension fluctuation rate <3%; lateral temperature difference <8°C; the matching relationship between the lateral movement speed of the intermediate roller (206) of the six-roll reversible rolling mill and the rolling speed: v_lateral movement = 0.3v_rolling mill ± 0.05m / s.

5. The six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 2, characterized in that: The intermediate roller transverse movement mechanism and the bending roller system of the six-roller reversible rolling mill support roller (205) are dynamically coupled through a stiffness matrix, and the stiffness matrix expression is: GPa / mm Among them, K[1.1], K[2,2], K[3,3] respectively correspond to the axial stiffness coefficients of the six-roll reversible rolling mill support roll (205), the six-roll reversible rolling mill intermediate roll (206) and the six-roll reversible rolling mill working roll (207).

6. The six-roller reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 5, characterized in that: Based on the system, a temperature-tension-roller displacement joint compensation model is proposed: ΔF=0.15×(T_act-T_set)×F0+0.02ΔS Wherein, ΔS is the transverse displacement of the intermediate roller (206) of the six-roll reversible rolling mill, F0 is the reference tension, T_act and T_set are the workpiece temperature and the rolling temperature, respectively.

7. The method of the six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to any one of claims 1 to 6, characterized in that: Including steps: Obtaining the roll system parameters of the six-roll reversible rolling mill: the diameter ratio of the six-roll reversible rolling mill support roll (205): the six-roll reversible rolling mill intermediate roll (206): the six-roll reversible rolling mill working roll (207) is 3.2:1.8:1, and the transverse travel of the six-roll reversible rolling mill intermediate roll (206) is ±150 mm; Based on the rolling temperature T_set = 300-400℃ and the temperature gradient of the yield strength of the magnesium alloy Δσ_s / ΔT = -0.38MPa / ℃, the temperature compensation tension deviation ΔF = 0.15×(T_act-T_set)×F0 is calculated, where F0 = 120kN; When ΔF>20%F0, the lateral displacement compensation of the intermediate roller (206) of the six-roller reversible rolling mill is performed: ΔS=10mm×(ΔF / 20%), and the bending roll force ΔF_bend=50kN×(ΔS / 10mm) of the support roller (205) of the six-roller reversible rolling mill is synchronously corrected.

8. The method of the six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 7, characterized in that: The intermediate roller lateral displacement compensation includes direction selection logic: When T_act>T_set, the middle roller (206) of the six-roller reversible rolling mill moves laterally toward the operating side; When T_act<T_set, the middle roller (206) of the six-roller reversible rolling mill moves laterally toward the transmission side; The traverse speed v=0.2×|T_act-T_set|mm / s, and the maximum does not exceed 20mm / s.

9. The method of the six-roll reversible rolling mill tension-temperature control system for magnesium alloy strip according to claim 7, characterized in that: Bending force correction amount of the support roller (205) of the six-roll reversible rolling mill ΔF_bend and the lateral displacement ΔS of the intermediate roller (206) of the six-roller reversible rolling mill satisfy the constraint condition: ΔF_bend 0.1× ×ΔS in, =1250mm is the diameter of the support roller (205) of the six-roller reversible rolling mill, =680mm is the diameter of the middle roller (206) of the six-roller reversible rolling mill.

Images