A method and system for constant speed and constant tension control in metal heat treatment processes

Abstract

This invention discloses a constant speed and constant tension control method and system in a metal heat treatment process. The equipment or system of the heat treatment process includes an uncoiling device, a winding device, a heat treatment furnace, a PLC control module, and a straightening device, as well as a speed sensor and a tension sensor. The speed sensor is used to measure the linear velocity of the heat-treated material, and the tension sensor is used to measure the tension of the material during the heat treatment process. Both the uncoiling device and the winding device are equipped with an adjustable-speed rotary motor and an encoder. By applying a constant tension to the heat-treated metal material and controlling a constant linear velocity, and by designing a reasonable speed and tension fine-tuning method based on the motor transfer function, constant speed and constant tension control is achieved. This overcomes the problem of traditional metal heat treatment only controlling the motor angular velocity and ignoring the impact of linear velocity and tension fluctuations and over-limits on the performance of the metal material, resulting in more stable product performance and a higher yield.

Description

Technical Field

[0001] This invention belongs to the field of metal heat treatment technology, specifically relating to a constant speed and constant tension control method and system in metal heat treatment processes. Background Technology

[0002] In the processing, forming, and composite rolling of metal materials, heat treatment is generally required through heating furnaces, annealing furnaces, and preheating furnaces (collectively referred to as heat treatment furnaces in this invention) to ensure the forming effect and performance of the metal materials.

[0003] In the current heat treatment process of metal coils, such as titanium alloy strips, the metal material at the unwinding end is treated in a heat treatment furnace and then wound up at the winding end. This is a continuous and dynamic process. Generally, only the rotational angular velocity of the winding device is set, and the unwinding end passively rotates to release the material. The entire system rotates and winds up at this constant angular velocity.

[0004] This method suffers from several drawbacks. Initially, the small winding diameter results in a low linear velocity of the metal material. As more material is wound and the diameter increases, the linear velocity also increases at a constant angular velocity. This means different sections of material exhibit varying linear velocities within the heat treatment furnace, leading to different heat treatment times. The significant difference in linear velocity between the initial and final sections results in substantial variations in the heat treatment outcome. Furthermore, traditional heat treatment methods only control the constant angular velocity, neglecting potential twisting or deformation of the metal strip. This often leads to less than ideal final heat treatment results. Typical performance impacts include uneven strength and toughness distribution, susceptibility to twisting and deformation, and a smaller tensile cross-section. Summary of the Invention

[0005] To address the above problems, this invention designs a constant speed and constant tension control method and system for metal heat treatment processes. By jointly controlling the constant tension and constant linear velocity of the heat-treated metal material, the performance of the heat-treated metal material can be guaranteed, and the product yield can be greatly improved.

[0006] This invention discloses a constant speed and constant tension control method for a metal heat treatment process. The equipment or system for this heat treatment process includes an uncoiling device, a winding device, a heat treatment furnace, a PLC control module, and a straightening device. It also includes a speed sensor and a tension sensor. The speed sensor measures the linear velocity of the heat-treated material, and the tension sensor measures the tension of the material during heat treatment. Both the uncoiling and winding devices are equipped with adjustable-speed rotary motors and encoders, such as traditional variable-frequency motors. The straightening device is a commonly used device in metal heat treatment. The encoder measures the rotation angle; through dynamic angle measurement, angular velocity and angular acceleration can be obtained. The method includes the following steps:

[0007] S0. Optimization of the unwinding and winding devices: The motors of the unwinding and winding devices are optimized when unloaded (with I-beams but without flat strips) to achieve maximum angular acceleration. And the moment of inertia I, by comparing the load feedback curve with the theoretical load feedback curve, if the fluctuation deviation is within 2%, the mechanical transmission mechanism is considered to meet the production requirements; this step is a preparatory work, and it only needs to be done once as long as the equipment has not changed significantly.

[0008] S1. Release the material, connect the unwinding device and the winding device, connect the material to the unwinding device and the winding device at both ends of the heat treatment furnace, and start the heat treatment device in time (generally, the heat treatment device should be started before the winding device is started), so that the material can be wound up as the winding device rotates after being processed by the heat treatment furnace.

[0009] S2. Adjust the straightening device, press down the straightening device and fix it. At this time, a constant resistance F2 is generated in the material running direction. The direction of the resistance is opposite to the direction of movement.

[0010] S3. Apply static tension: When the material is conveyed from the unwinding device to the winding device and fixed on the winding device, the unwinding device and the winding device apply opposite torques that constitute tension, thus applying static tension. The measured static tension value is required to be within the first threshold range of tension deviation. The first threshold range of tension deviation is a threshold range based on the target tension value F. m =kbh, in Newtons (N), where k is the tension control coefficient, b is the material width, and h is the material thickness, both in mm. When the measured tension F3 reaches the target tension value F... m Maintain this tension within the allowable deviation range;

[0011] S4. Adjust the running speed. The motors of the unwinding and winding devices gradually increase their speed from a static state (during the speed adjustment process from static to the set value, the tension may also deviate or fluctuate, and the tension deviation or fluctuation is allowed to be within the second threshold of the tension deviation). When the speed sensor feedback value deviates from the set target speed to within the second threshold of the speed deviation, it is considered that the speed has reached the target value.

[0012] Furthermore, after the speed and tension have basically reached and stabilized (meeting the second threshold requirements for speed deviation and the second threshold requirements for tension deviation respectively), fine adjustments are made to ensure that the speed and tension meet the first threshold requirements for speed deviation and the first threshold requirements for tension deviation respectively, wherein the first threshold for speed deviation is less than the second threshold for speed deviation.

[0013] Furthermore, the angular velocity control methods for the winding and unwinding devices include angular velocity control methods based on the Archimedes spiral equation.

[0014] Furthermore, the constant tension control method includes: the tension setpoint is sent by the PLC control module to the motor frequency converters of both the unwinding device and the winding device simultaneously, prioritizing the adjustment of the unwinding device torque and secondarily adjusting the winding device torque, with the tension increasing or decreasing accordingly; when the tension sensor reports that the tension has reached the set target value, the coarse tension adjustment is stopped; it is determined whether the tension fluctuation meets the requirements; if not, the unwinding device or the winding device is finely adjusted so that the tension fluctuation is near its average value, and the PLC output signal is maintained.

[0015] Furthermore, the constant speed control method includes, after the material tension is adjusted, the operator sets a target speed V on the operation interface, according to V=r The frequency regulation, voltage regulation, or current regulation is calculated using t and the motor transfer function.

[0016] in, The set step adjustment angular acceleration, .

[0017] Furthermore, when the speed and / or tension exceed the limit, the control methods used include over-limit control method one or over-limit control method two.

[0018] Furthermore, the first over-limit control method includes: when the measured speed exceeds the tolerance:

[0019] S41. The PLC control module issues an adjustment command, and the winding device motor fine-tunes the speed value according to "speed fine-tuning amount = speed deviation amount * first proportional coefficient k1", and waits until the speed is basically stable.

[0020] S42. Compare the measured tension value to see if it exceeds the tolerance. If the tension does not exceed the tolerance, compare the speed again to see if it still exceeds the tolerance. If both are within tolerance, the adjustment is complete. If the speed still exceeds the tolerance, continue to fine-tune the speed according to the previous adjustment amount and then compare the tension again to see if it exceeds the tolerance. If the tension exceeds the tolerance, the unwinding device fine-tunes the tension value according to "tension fine-tuning amount = tension tolerance amount * second proportional coefficient k2".

[0021] S43. Wait for a certain period of time again until the tension is basically stable (re-compare the speed to see if it exceeds the tolerance; if it does, repeat the above S41 to S43 process; if both speed and tension do not exceed the tolerance, the over-limit control is completed).

[0022] The second over-limit control method includes: when the measured tension exceeds the tolerance...

[0023] S4a. The PLC control module issues an adjustment command, and the unwinding device motor fine-tunes the tension value according to "tension fine-tuning amount = tension deviation amount * second proportional coefficient k2", and waits until the tension is basically stable.

[0024] S4b. Compare the measured speed value to see if it exceeds the tolerance. If it does not exceed the tolerance, compare the tension value again to see if it still exceeds the tolerance. If it does not exceed the tolerance, the adjustment is complete. If the tension value still exceeds the tolerance, continue to fine-tune the tension according to the previous adjustment amount and then compare the speed value again to see if it exceeds the tolerance. If the speed exceeds the tolerance, the winding device fine-tunes the speed value according to "speed fine-tuning amount = speed tolerance amount * first proportional coefficient k1".

[0025] S4c: Wait for a certain period of time again. After the speed has basically stabilized, compare the tension again to see if it exceeds the tolerance. If it does, repeat the above process S4a to S4c. If neither the speed nor the tension exceeds the tolerance, the over-limit control is complete.

[0026] When the measured speed and tension both exceed the tolerance (both exceed their respective first deviation thresholds), either over-limit control method one or over-limit control method two shall be used.

[0027] Furthermore, when both measured speed and tension exceed the tolerance, tension control is prioritized, with speed control used as a secondary measure.

[0028] On the other hand, a constant speed and constant tension control system for a metal heat treatment process, wherein the system adopts any of the aforementioned constant speed and constant tension control methods for metal heat treatment processes.

[0029] Furthermore, the system is sequentially configured with an unwinding device, a straightening device, a tension and speed measuring device, a heat treatment furnace, and a winding device. The unwinding device, tension and speed measuring device, and winding device are electrically connected to a PLC control module. The tension and speed measuring device includes a speed sensor and a tension sensor. The speed sensor is used to measure the linear velocity of the heat-treated material, and the tension sensor is used to measure the tension of the material during the heat treatment process. Both the unwinding device and the winding device are equipped with an adjustable-speed rotary motor and an encoder. The heat treatment furnace includes a heating section, a soaking section, and a cooling section.

[0030] The advantages and beneficial effects of this invention are as follows: The constant speed and constant tension control method and system designed in this invention for metal heat treatment process can ensure uniform and stable heating and stress during metal heat treatment, resulting in a final product with uniform crystal structure and minimal changes, and no diameter reduction problem (the cross-sectional dimensions remain basically unchanged before and after annealing). Taking the heat treatment of titanium alloy strips as an example, when unwinding and cutting, there is no longer any autonomous deformation, and the product yield is greatly improved. The traditional method heat-treats about 1500m of metal coil in one go, with a yield of about 80%. After the improvement, the yield can reach more than 97%. The defective products are mainly the starting and ending sections, which can be directly removed from both ends. Attached Figure Description

[0031] Figure 1 This is a connection diagram of a constant speed and constant tension control system in a metal heat treatment process.

[0032] Figure 2 This is a block diagram of a constant speed and constant tension control method in a metal heat treatment process;

[0033] Figure 3 This is a block diagram of an over-limit control method;

[0034] Figure 4 This is the block diagram of over-limit control method two. Detailed Implementation

[0035] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1

[0037] This invention discloses a constant speed and constant tension control method in a metal heat treatment process, such as... Figure 1As shown, the equipment or system for the heat treatment process includes an uncoiling device, a winding device, a heat treatment furnace, a PLC control module, and a straightening device. The equipment or system also includes a speed sensor and a tension sensor. The speed sensor measures the linear velocity of the heat-treated material, and the tension sensor measures the tension of the material during heat treatment. Both the uncoiling and winding devices are equipped with adjustable-speed rotary motors and encoders, such as traditional variable-frequency motors. The straightening device is a commonly used device in metal heat treatment. The encoder measures the rotation angle; dynamic angle measurement can obtain angular velocity and angular acceleration measurements. In this embodiment, the straightening device uses a set of upper and lower staggered rollers. The speed sensor and tension sensor are integrated into a three-wheel structure: an auxiliary wheel at the inlet, a speed measuring wheel at the outlet, and a tension measuring wheel in the middle. The combined speed sensor and tension sensor are called a tension-speed measuring device. Constant tension refers to constant winding tension, and constant speed refers to constant winding linear velocity, ensuring that the tension and speed of the material in the heat treatment furnace remain constant. Figure 2 As shown, the method includes the following steps:

[0038] S0. Optimization of the unwinding and winding devices: The motors of the unwinding and winding devices are optimized when unloaded (with I-beams but without flat strips) to achieve maximum angular acceleration. The moment of inertia I (used for updating transfer function parameters) is compared with the theoretical load feedback curve using the load feedback curve. If the fluctuation or deviation is within 2%, the mechanical transmission mechanism is considered to meet production requirements. In this embodiment, the optimization software built into the frequency converter is directly used for testing and optimization. This step is not required for every heat treatment. Generally, a motor optimization should be performed before the use of a set of equipment to obtain relevant parameters. If there are no major performance changes or fault repairs afterward, it can be skipped, and the most recent optimization result can be used directly. It is generally recommended that even if no abnormalities occur, optimization should be performed regularly, such as every six months or every year.

[0039] S1. Release the material, connect the unwinding device and the winding device, connect the material to the unwinding device and the winding device at both ends of the heat treatment furnace, and start the heat treatment device in time (generally, the heat treatment device should be started before the winding device is started), so that the material can be wound up as the winding device rotates after being processed by the heat treatment furnace.

[0040] S2. Adjust the straightening device, press down the straightening device and fix it. At this time, a constant resistance F2 is generated in the material running direction. The direction of the resistance is opposite to the direction of movement.

[0041] S3. Apply static tension. When the material is conveyed from the unwinding device to the winding device and fixed thereon, the unwinding and winding devices apply opposing torques that constitute tension. In this embodiment, the unwinding device applies a leftward torque (counterclockwise), and the winding device applies a rightward torque (clockwise). Static tension is applied, requiring the measured static tension value to be within the first threshold range of tension deviation. The first threshold range of tension deviation is a threshold range based on the target tension value F. m =kbh, in Newtons (N), where k is the tension control coefficient, and in this embodiment, k = 2–5 N / mm. 2 b is the material width, and h is the material thickness, both in mm. When the measured tension F3 reaches the target tension value F... m When the allowable deviation range is within which the tension is maintained, this embodiment sets the first threshold for allowable tension deviation to be ±3% of the target tension value, i.e., |F3-F m | / F m ≤0.03; such as Figure 1 As shown, the straightening device, speed sensor, and tension sensor are in a static tension state at this time, F3 = F1 + F2, where F1 is the unwinding tension and the measured tension F3 is the winding tension.

[0042] The basic method for tension control is: tension F = T * D = U * K * D, where T is the motor torque, D is the diameter of the I-beam reel, U is the inverter output voltage, and K is the motor torque coefficient. In addition, the tension loading speed Af is the set value F = Af * t, where t is the continuous loading time, F includes F1 and F3, and the other parameters are the corresponding unwinding and rewinding device parameters.

[0043] S4. Adjust the running speed. The motors of the unwinding and winding devices gradually increase their speed from a static position (during the speed adjustment process from static to the set value, tension may fluctuate or deviate. Tension fluctuation or deviation is allowed to be controlled within the second threshold of tension deviation. If the deviation exceeds the range, it should be adjusted. In this embodiment, the second threshold of tension deviation is set to ±5% of the target tension value). When the speed sensor feedback value deviates from the set target speed by within the second threshold of speed deviation, the speed is considered to have reached the target value. In this embodiment, the second threshold of speed deviation is set to ±5% of the target speed value. The equipment or system of the heat treatment process heat-treats the material according to the set speed and tension until completion. The running speed is the linear speed of the material, which is essentially achieved by adjusting the angular velocity of the motor rotation.

[0044] When the diameter of the unwinding device decreases and the rotational speed (angular velocity) approaches the set value ω0=V0 / (πD), the PLC outputs a command to indicate that the roll material is low and needs to be changed, where V0 is the set linear velocity, π is the circumference of a circle, and D is the bottom diameter of the I-beam wheel or the minimum roll diameter.

[0045] Generally, frequency converters control motors by changing the output voltage, current, or frequency to change the motor's state. In this embodiment, the motor output torque is changed by adjusting the voltage, thereby adjusting the tension, and the motor speed is changed by adjusting the frequency converter frequency.

[0046] Preferably, after the speed and tension have basically reached and stabilized (meeting the second threshold requirements for speed deviation and the second threshold requirements for tension deviation respectively), fine-tuning is continued to make the speed and tension meet the first threshold requirements for speed deviation and the first threshold requirements for tension deviation respectively. The first threshold for speed deviation is less than the second threshold for speed deviation. In this embodiment, the first threshold for speed deviation is taken as ±4% of the target speed value.

[0047] Preferably, the angular velocity control method for the winding and unwinding devices includes an angular velocity control method based on the Archimedes spiral equation.

[0048] The angular velocity control method based on the Archimedes spiral equation is as follows: During system operation, the change in the roll diameter r (radius or diameter, calculated using radius in this embodiment) during material winding and unwinding follows the Archimedes spiral equation, i.e.

[0049] r=a+cθ

[0050] Where a is the distance from the starting point of the winding to the origin of the polar coordinates, which is a constant; c=h / (2π) is the value that increases with each unit angle r of the spiral, that is, the angle increases by 360 degrees for each revolution, and the radius increases with the thickness h of the material; θ is the angle of continuous winding of the Archimedean spiral, expressed in radians. In fact, the winding point θ=0, and after 2 revolutions, θ=4π.

[0051] The relationship between linear velocity V and angular velocity ω based on the Archimedes spiral equation can be obtained by differentiating over time.

[0052] V=cθ 2 +(a+cθ)ω

[0053] Therefore,

[0054] ω=(V-cθ 2 ) / (a+cθ)

[0055] The angular velocity of the winding and unwinding device can be determined in real time based on the constant linear velocity requirement and the Archimedean spiral rotation angle. It's important to note that because strip materials are typically wound in a discontinuous Archimedean spiral, different layers of material follow the Archimedean spiral equation, while a single layer may have multiple turns, all with the same diameter and consistent angular velocity. Therefore, for winding methods with multiple turns within the same layer, the unwinding angular velocity control should combine segmented angular velocity control based on the Archimedean spiral equation with inter-segment (same layer) angular velocity control. For winding methods with only one turn per layer (i.e., a continuous Archimedean spiral), the control method is simpler; a direct angular velocity control method based on the Archimedean spiral equation is sufficient.

[0056] Preferably, the constant speed control method includes, after the material tension is adjusted, the operator sets the target speed V on the operation interface. In this embodiment, the linear speed control is mainly based on the winding speed, and the PLC simultaneously sends a speed command to the winding inverter (or vice versa). The speed is determined according to V=r The frequency adjustment, voltage adjustment, or current adjustment is calculated using the motor transfer function. In this embodiment, the speed is mainly adjusted by adjusting the motor frequency. The speed is adjusted once every second. When the speed measured by the speedometer matches the set speed, the speed control ends.

[0057] in, The set step adjustment angular acceleration, In this embodiment, .

[0058] To implement this control method, the unwinding device and the winding device should be equipped with an angle measuring instrument and / or an angular velocity measuring instrument. In this embodiment, encoders are respectively set to perform real-time angle measurement.

[0059] Example 2

[0060] The difference from Embodiment 1 is that this embodiment considers tension fine-tuning. The constant tension control method includes: the tension setpoint is sent by the PLC control module to the motor inverters of both the unwinding and winding devices simultaneously, prioritizing the adjustment of the unwinding device torque and secondarily adjusting the winding device torque (adjusting the torque can change the tension; if the unwinding motor torque is not adjusted to the target value at least once, and the actual effect is not obvious, such as when the unwinding motor torque is close to the maximum value or significantly large, or when multiple adjustments have not yielded significant results, the winding motor torque can be adjusted; the priority adjustment and priority control mentioned in this invention can be understood in this way). The tension is increased or decreased accordingly. When the tension sensor reports that the tension has reached the set target value, the coarse tension adjustment is stopped. It is then determined whether the tension fluctuation meets the requirements. In this embodiment, less than 1% of the average value is used as the judgment condition. If not, the unwinding or winding device is fine-tuned so that the tension fluctuation is near its average value, that is, the tension is fine-tuned to reduce the fluctuation to within 1%, and the PLC output signal is maintained.

[0061] To avoid excessive impact, motor adjustment is usually done using a stepping method, such as increasing / decreasing the output value of voltage, current or frequency by one frame per second. The step size is mainly to achieve the adjustment quickly and smoothly, which is called coarse adjustment. After the adjustment is basically in place, the step size is reduced for fine adjustment.

[0062] When adjusting the speed over a wide range, you can also distinguish between coarse adjustment and fine adjustment, as well as combinations thereof.

[0063] Generally, coarse and fine adjustments are used when applying static tension and starting operation. Fine adjustments are used when tension or speed fluctuates significantly or exceeds limits during operation.

[0064] Example 3

[0065] The difference from Example 2 lies in the control method employed when speed and / or tension exceed limits. This includes either Over-Limit Control Method 1 or Over-Limit Control Method 2. Since a change in either speed or tension will affect the other, these two parameters need to be controlled separately, with cyclical fine-tuning to gradually approach the target value. The Over-Limit mentioned in this invention includes measured values ​​exceeding limits during fluctuations. When fluctuations are large, fine-tuning methods are generally used, i.e., reducing the step size of frequency, voltage, or current to adjust tension and / or speed. This embodiment prioritizes tension control by the unwinding device and speed control by the winding device.

[0066] Preferred, such as Figure 3 As shown, the first over-limit control method includes: when the measured speed exceeds the tolerance (exceeds the allowable range of the target speed; in this embodiment, a first threshold value for speed deviation is taken):

[0067] S41. The PLC control module issues an adjustment command, and the winding device motor fine-tunes the speed value according to "speed fine-tuning amount = speed deviation amount * first proportional coefficient k1" (in reality, the PLC fine-tunes the frequency converter frequency according to the speed fine-tuning amount and the motor transfer function). In this embodiment, k1=50%. Since speed adjustment will inevitably affect the tension change, it is necessary to wait for a certain period of time, generally until the speed is basically stable (in this embodiment, the speed is basically stable after 5 seconds of fine-tuning).

[0068] S42. Compare the measured tension value to see if it exceeds the tolerance (exceeding the allowable range of the target tension; in this embodiment, the first threshold value of tension deviation is taken). If the tension does not exceed the tolerance, compare the speed again to see if it still exceeds the tolerance. If both are within tolerance, the adjustment is complete. If the speed still exceeds the tolerance, continue to fine-tune the speed according to the previous adjustment amount and then compare the tension again to see if it exceeds the tolerance. If the tension exceeds the tolerance, the unwinding device fine-tunes the tension value according to "tension fine-tuning amount = tension deviation amount * second proportional coefficient k2" (in reality, the PLC fine-tunes the motor voltage or current according to the fine-tuning tension fine-tuning amount and the motor transfer function). In this embodiment, k2 = 30%.

[0069] S43. Wait for a certain period of time again until the tension is basically stable (in this embodiment, after 5 seconds of tension fine-tuning), and then compare the speed again to see if it exceeds the tolerance. If it does, repeat the above S41 to S43 process. If both the speed and tension do not exceed the tolerance, the over-limit control is completed. The diagram uses two diamond blocks to represent the judgment of whether the tension exceeds the tolerance. Essentially, it is the same thing. The flowchart is drawn in this way to express the situation where both the speed and tension do not exceed the tolerance.

[0070] The second over-limit control method includes: when the measured tension exceeds the tolerance (exceeds the allowable range of the target tension, i.e., the over-limit is too large; in this embodiment, the first threshold value of the tension deviation is taken), such as... Figure 4 As shown,

[0071] S4a. The PLC control module issues an adjustment command, and the unwinding device motor fine-tunes the tension value according to "tension fine-tuning amount = tension deviation amount * second proportional coefficient k2". In fact, the PLC fine-tunes the motor voltage or current according to the tension fine-tuning amount and the motor transfer function. In this embodiment, k2=30%. Wait until the tension is basically stable (in this embodiment, the tension is basically stable after 5 seconds of fine-tuning).

[0072] S4b. Compare the measured speed value to see if it exceeds the tolerance (exceeding the allowable range of the target speed; in this embodiment, the first threshold value of speed deviation is taken). If there is no tolerance, compare the tension again to see if it still exceeds the tolerance. If there is no tolerance, the adjustment is complete. If the tension still exceeds the tolerance, continue to fine-tune the tension according to the previous adjustment amount and then compare the speed again to see if it exceeds the tolerance. If the speed exceeds the tolerance, the winding device fine-tunes the speed value according to "speed fine-tuning amount = speed tolerance amount * first proportional coefficient k1" (in reality, the PLC fine-tunes the frequency converter frequency according to the speed fine-tuning amount and the motor transfer function). In this embodiment, k1 = 50%.

[0073] S4c. Wait for a certain period of time again until the speed is basically stable (in this embodiment, after 5 seconds of speed fine-tuning), and then compare the tension again to see if it exceeds the tolerance. If it does, repeat the above S4a to S4c process. If neither the speed nor the tension exceeds the tolerance, then the over-limit control is completed. The main difference between the second control method and the first control method is that the tension and speed are interchanged, the winding and unwinding devices are interchanged, and the fine-tuning amount is made according to their respective set ratios.

[0074] When the measured speed and tension both exceed the tolerance (both exceed their respective first tolerance thresholds), either over-limit control method one or over-limit control method two shall be used.

[0075] If the strategy is adjusted so that the winding device prioritizes tension control and the unwinding device prioritizes speed control, then the over-limit control method one and over-limit control method two only require adaptive changes to the device object, while the basic principles and steps remain unchanged.

[0076] Preferably, when both measured speed and tension exceed tolerances, tension control should be prioritized, with speed control used as a secondary measure, as in over-limit control method two. This design primarily considers that speed changes mainly affect the heat treatment time of the material in the furnace, and their impact on material properties is not immediately apparent; while tension directly affects material properties by influencing the internal structure of the material. Therefore, prioritizing tension adjustment can reduce the impact of exceeding limits on material properties. If the over-limit ranges for both speed and tension are small, the actual impact of the order of adjustment is not significant.

[0077] Example 4

[0078] The difference from Example 3 is that this example is implemented by controlling the tension with the winding device and controlling the speed with the unwinding device.

[0079] Example 5

[0080] A constant speed and constant tension control system for a metal heat treatment process, wherein the system employs a constant speed and constant tension control method for a metal heat treatment process as described in any one of Examples 1 to 4, or a preferred combination thereof.

[0081] Preferably, the system is sequentially configured with an unwinding device, a straightening device, a tension and speed measuring device, a heat treatment furnace, and a winding device. The unwinding device, tension and speed measuring device, and winding device are electrically connected to a PLC control module. The tension and speed measuring device includes a speed sensor and a tension sensor. The speed sensor is used to measure the linear velocity of the heat-treated material, and the tension sensor is used to measure the tension of the material during the heat treatment process. Both the unwinding device and the winding device are equipped with an adjustable-speed rotary motor and an encoder. The heat treatment furnace includes a heating section, a soaking section, and a cooling section.

[0082] The basic principle of this invention is as follows: By setting up tension and speed monitoring devices, and based on real-time monitoring results and the physical parameters and transfer function models of the unwinding and winding devices, the tension and speed are adjusted step by step to approach the target values. This allows the metal material to complete the heat treatment process with a relatively stable cycle and tension, resulting in a more uniform internal crystal structure, more stable performance, and no diameter reduction phenomenon. During the initial startup of the heat treatment, the straightening device is set first, followed by the application of static tension, and then the application of speed, gradually starting up to the target tension and speed. The system can enter a steady state at a faster speed, improving efficiency while ensuring product performance.

[0083] The above description is only a part of the relatively systematic and comprehensive constant speed and constant tension control method and system embodiment in the metal heat treatment process of the present invention. In fact, speed and tension can also be adjusted directly by fine adjustment. During static start-up, tension can be applied during or after start-up. In dynamic situations, speed can be adjusted first and then tension can be adjusted, especially when there are deviations in both tension and speed but the speed deviation is large. These combinations or preferred solutions should also be considered within the scope of protection of the present invention, and will not be listed one by one here.

Claims

1. A constant speed and constant tension control method in a metal heat treatment process, wherein the heat treatment process system includes an uncoiling device, a winding device, a heat treatment furnace, a PLC control module, and a straightening device, characterized in that, The system for the heat treatment process also includes a speed sensor and a tension sensor. The speed sensor is used to measure the linear velocity of the heat-treated material, and the tension sensor is used to measure the tension of the material during the heat treatment process. Both the unwinding device and the winding device are equipped with adjustable-speed rotary motors and encoders. The method includes the following steps: S1. Release the material by connecting the material to an unwinding device and a winding device at both ends of the heat treatment furnace. S2. Adjust the straightening device, press down the straightening device and fix it. At this time, a constant resistance F2 is generated in the material running direction. S3. Apply static tension: When the material is conveyed from the unwinding device to the winding device and fixed on the winding device, the unwinding device and the winding device apply opposite torques that constitute tension, thus applying static tension. The measured static tension value is required to be within the first threshold range of tension deviation. The first threshold range of tension deviation is a threshold range based on the target tension value F. m =kbh, where k is the tension control coefficient, b is the material width, and h is the material thickness; S4. Adjust the running speed. The motors of the unwinding and winding devices gradually increase the speed from a static state. When the speed sensor feedback value deviates from the set target speed within the second speed deviation threshold, the speed is considered to have reached the target value. When the speed and / or tension exceed the limit, the control methods used include over-limit control method one or over-limit control method two. The first over-limit control method includes: when the measured speed exceeds the tolerance... S41. The PLC control module issues an adjustment command, and the winding device motor fine-tunes the speed value according to "speed fine-tuning amount = speed deviation amount * first proportional coefficient k1", and waits until the speed stabilizes. S42. Compare the measured tension value to see if it exceeds the tolerance. If it does not exceed the tolerance, compare the speed again to see if it still exceeds the tolerance. If it does not exceed the tolerance, the adjustment is complete. If the speed still exceeds the tolerance, continue to fine-tune the speed according to the previous adjustment amount and then compare the tension again to see if it exceeds the tolerance. If the tension exceeds the tolerance, the unwinding device fine-tunes the tension value according to "tension fine-tuning amount = tension excess amount * second proportional coefficient k2". S43. After the tension stabilizes, re-compare the speed to see if it exceeds the tolerance. If it does, repeat the above S41 to S43 process. If both the speed and tension do not exceed the tolerance, the over-limit control is complete. The second over-limit control method includes: when the measured tension exceeds the tolerance... S4a. The PLC control module issues an adjustment command, and the unwinding device motor fine-tunes the tension value according to "tension fine-tuning amount = tension deviation amount * second proportional coefficient k2", and waits until the tension stabilizes. S4b. Compare the measured speed value to see if it exceeds the tolerance. If it does not exceed the tolerance, compare the tension value again to see if it still exceeds the tolerance. If it does not exceed the tolerance, the adjustment is complete. If the tension value still exceeds the tolerance, continue to fine-tune the tension according to the previous adjustment amount and then compare the speed value again to see if it exceeds the tolerance. If the speed exceeds the tolerance, the winding device fine-tunes the speed value according to "speed fine-tuning amount = speed tolerance amount * first proportional coefficient k1". S4c: After the speed stabilizes, re-compare the tension to see if it exceeds the tolerance. If it does, repeat the above process S4a to S4c. If both the speed and tension do not exceed the tolerance, the over-limit control is complete. When the measured speed and tension both exceed the tolerance, either over-limit control method one or over-limit control method two shall be adopted.

2. The constant speed and constant tension control method in a metal heat treatment process according to claim 1, characterized in that, After the speed and tension are stabilized, fine-tuning continues to ensure that the speed and tension meet the requirements of the first threshold for speed deviation and the first threshold for tension deviation, respectively, wherein the first threshold for speed deviation is less than the second threshold for speed deviation.

3. The constant speed and constant tension control method in a metal heat treatment process according to claim 1, characterized in that, The angular velocity control methods for the winding and unwinding devices include angular velocity control methods based on the Archimedes spiral equation.

4. The constant speed and constant tension control method in a metal heat treatment process according to claim 1, characterized in that, Once the material tension is adjusted, a target speed V is given, and the frequency adjustment, voltage adjustment, or current adjustment is calculated according to the motor transfer function.

5. The constant speed and constant tension control method in a metal heat treatment process according to claim 1, characterized in that, The tension setting is achieved by the PLC control module simultaneously sending rotation signals to both the unwinding and winding devices. Priority is given to adjusting the torque of the unwinding device, with adjustment of the torque of the winding device as a secondary measure. Coarse tension adjustments are made as the tension increases or decreases. Coarse tension adjustment stops when the measured tension value reaches the first threshold of tension deviation. The system then checks whether the tension fluctuation meets the requirements. If not, it fine-tunes the unwinding or winding device to bring the tension fluctuation close to its average value, while maintaining the PLC output signal.

6. The constant speed and constant tension control method in a metal heat treatment process according to claim 1, characterized in that, When both measured speed and tension exceed the tolerance, tension control should be prioritized, with speed control used as a secondary measure.

7. A constant speed and constant tension control system for a metal heat treatment process, characterized in that, The system employs a constant speed and constant tension control method in a metal heat treatment process as described in any one of claims 1 to 6.

8. A constant speed and constant tension control system in a metal heat treatment process according to claim 7, characterized in that, The system is sequentially configured with an unwinding device, a straightening device, a tension and speed measuring device, a heat treatment furnace, and a winding device. The unwinding device, tension and speed measuring device, and winding device are electrically connected to a PLC control module. The tension and speed measuring device includes a speed sensor and a tension sensor.

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