Steel plate cooling compensation control method based on speed-flow dynamic coupling

Abstract

The application discloses a kind of steel plate cooling compensation control method and system based on speed-flow dynamic coupling, belong to steel rolling control technical field;The method is aimed at the problem that the speed of steel plate is suddenly reduced and the tail is supercooled due to the steel biting of straightening machine in short process production line, by real-time acquisition of the deviation of steel plate set speed and actual speed, combined with the flow-speed relationship coefficient calculated by cooling model, dynamically calculate the flow compensation value, while introducing the adaptive gain coefficient K calculated based on the thickness of steel plate and target cooling rate, to intelligently adjust the compensation sensitivity, the compensation value calculated is limited after processing, dynamically adjust the original set flow and issue to cooling header;The application can effectively eliminate the longitudinal temperature unevenness of steel plate, control the head-tail temperature difference within 30 DEG C, significantly improve the shape quality and production line efficiency.

Description

Technical Field

[0001] This invention relates to the field of automated control technology for steel rolling, specifically a steel plate cooling compensation control method based on dynamic coupling of speed and flow. Background Technology

[0002] Heavy plates are key materials for major equipment manufacturing and infrastructure construction, and their microstructure and mechanical properties are largely determined by the post-rolling cooling process. Ideally, the steel plate should pass through the cooling zone at a constant speed to achieve uniform cooling under a constant cooling water flow rate. However, in actual short-process production lines, due to space constraints, the cooling zone outlet is too close to the hot straightener inlet. When the head of the steel plate enters the straightener, the straightener actively slows down to ensure smooth engagement. This speed command is transmitted and forces the tail of the steel plate, still in the cooling zone, to slow down synchronously. This results in the tail's residence time Δt in the cooling zone being much longer than the set time. Under the traditional constant flow control mode, with a constant cooling water volume Q, the extended cooling time means a significant increase in the heat exchange per unit area Q×Δt at the tail, causing overcooling at the tail. Actual measurements show that the temperature difference between the beginning and end of the steel plate can reach over 80℃, leading to severe quality defects such as plate warping and uneven performance, resulting in a significant drop in product qualification rate. Currently available technical solutions mostly focus on optimizing the layout of cooling manifolds, improving nozzle structure, or adopting feedforward-feedback temperature control models. However, these methods cannot fundamentally solve the core disturbance problem caused by sudden speed changes due to the intervention of the straightening machine. Existing systems lack a rapid response mechanism capable of sensing speed changes in real time and dynamically adjusting the cooling water flow accordingly. Therefore, there is an urgent need in this field for an intelligent compensation algorithm that can dynamically couple the speed signal with the flow rate setting in real time to offset the impact of speed fluctuations and ensure uniform cooling along the entire length of the steel plate. Summary of the Invention

[0003] The purpose of this invention is to solve the technical problems existing in the prior art and to provide a steel plate cooling compensation control method based on speed-flow dynamic coupling.

[0004] This invention provides the following technical solution: a steel plate cooling compensation control method based on velocity-flow dynamic coupling, comprising the following steps:

[0005] S1. Real-time acquisition of the set speed V_set and actual running speed V_act of the steel plate, and calculation of the speed deviation ΔV, ΔV=V_set-V_act;

[0006] S2. Obtain the flow-velocity relationship coefficient DFlow_DSpeed ​​calculated by the cooling model. This coefficient is calculated in real time by the model based on parameters such as the chemical composition of the current steel grade, the target cooling rate, and the thickness. Its physical meaning is "the flow rate change required to match the unit velocity change", and its dimension is (L / s) / (m / s).

[0007] S3. Based on the speed deviation and the relationship coefficient, a flow compensation ratio flowTrim is calculated, flowTrim=△V×DFlow_DSpeed;

[0008] S4. Apply the flow compensation ratio to the original set flow Original_Flow to generate a new flow set value New_Flow, New_Flow = Original_Flow × (1 + flowTrim), where Original_Flow is the set flow issued by the original cooling model.

[0009] S5. The new flow rate setting value is sent to the execution unit of the cooling manifold to achieve dynamic adjustment of the flow rate.

[0010] Furthermore, in step S3, when calculating the flow compensation ratio flowTrim, a configurable gain coefficient K is introduced to adjust the sensitivity of the compensation: flowTrim = ΔV × DFlow_DSpeed ​​× K.

[0011] Furthermore, the gain coefficient K = 1 + (H_act × σ × C_target / C_ref),

[0012] Where H_act is the actual thickness of the steel plate, σ is the thickness influence factor, C_target is the target cooling rate, and C_ref is the reference cooling rate constant.

[0013] Furthermore, K is limited to the range of [0.8, 1.5].

[0014] Furthermore, the calculated preliminary flow compensation ratio is subjected to amplitude limiting processing to constrain it within a safe range of [-M, +M], where M≤0.1.

[0015] Furthermore, in step S4, New_Flow is compared and constrained with the preset manifold flow range [Min_Flow, Max_Flow] to ensure that the output value does not exceed the device limits.

[0016] Furthermore, in step S2, the flow-velocity relationship coefficient DFlow_DSpeed ​​is calculated and provided in real time by the upstream process control computer L2 system based on the chemical composition, thickness, and target cooling rate of the steel.

[0017] The method is implemented by a DCS distributed control system or a PLC controller, the system comprising:

[0018] Speed ​​sensing module: used to acquire the actual speed of the steel plate in real time;

[0019] Data communication module: used to interact with the L2 process computer to obtain the DFlow_DSpeed ​​coefficient and the original set flow rate;

[0020] Compensation calculation module: Embedded in the tracking program (such as the mpTrack process) of the controller, it is used to execute the corresponding algorithms in each step;

[0021] Control output module: Used to send the adjusted flow command to the actuator.

[0022] Compared with existing technologies, the beneficial effects of this invention are: 1. By using dynamic flow compensation, the cooling time difference caused by sudden speed changes is fundamentally eliminated, reducing the temperature difference between the beginning and end of the steel plate from 80-120℃ to within 30℃, effectively avoiding warping and uneven performance; 2. The plate shape quality is significantly improved, the consistency of product performance is greatly enhanced, and the yield rate is increased by about 3-5%; 3. There is no need to manually reduce the speed to match the speed, ensuring that the production line operates stably at the designed speed, and the production capacity is released; 4. Multiple parameter limiting ensures the stability of the system and the safety of the equipment under various disturbances; 5. By setting the gain coefficient K, it can automatically adjust according to the thickness and cooling rate of the steel plate. For thick plates or steel plates with high cooling rate requirements, the compensation sensitivity is automatically increased to ensure the compensation effect; for thin plates, the gain is appropriately reduced to prevent system overshoot, realizing one-click adaptive optimization control. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall architecture of the system of the present invention;

[0024] Figure 2 This is a flowchart of the flow compensation control algorithm of the present invention. Detailed Implementation

[0025] Example 1

[0026] This embodiment is a steel plate cooling compensation control method based on velocity-flow dynamic coupling, including the following steps:

[0027] S1. Real-time acquisition of the set speed V_set and actual running speed V_act of the steel plate, and calculation of the speed deviation ΔV, ΔV=V_set-V_act;

[0028] S2. Obtain the flow-velocity relationship coefficient DFlow_DSpeed ​​calculated by the cooling model. This coefficient is calculated in real time by the model based on parameters such as the chemical composition of the current steel grade, the target cooling rate, and the thickness. Its physical meaning is "the flow rate change required to match the unit velocity change", and its dimension is (L / s) / (m / s).

[0029] S3. Based on the speed deviation and the relationship coefficient, a flow compensation ratio flowTrim is calculated, flowTrim=△V×DFlow_DSpeed;

[0030] S4. Apply the flow compensation ratio to the original set flow Original_Flow to generate a new flow set value New_Flow, New_Flow = Original_Flow × (1 + flowTrim), where Original_Flow is the set flow issued by the original cooling model.

[0031] S5. The new flow rate setting value is sent to the execution unit of the cooling manifold to achieve dynamic adjustment of the flow rate.

[0032] Furthermore, in step S3, when calculating the flow compensation ratio flowTrim, a configurable gain coefficient K is introduced to adjust the sensitivity of the compensation: flowTrim = ΔV × DFlow_DSpeed ​​× K.

[0033] Furthermore, the gain coefficient K = 1 + (H_act × σ × C_target / C_ref),

[0034] Where H_act is the actual thickness of the steel plate, σ is the thickness influence factor, C_target is the target cooling rate, and C_ref is the reference cooling rate constant.

[0035] Furthermore, K is limited to the range of [0.8, 1.5].

[0036] Furthermore, the calculated preliminary flow compensation ratio is subjected to amplitude limiting processing to constrain it within a safe range of [-M, +M], where M≤0.1.

[0037] Furthermore, in step S4, New_Flow is compared and constrained with the preset manifold flow range [Min_Flow, Max_Flow] to ensure that the output value does not exceed the device limits.

[0038] Furthermore, in step S2, the flow-velocity relationship coefficient DFlow_DSpeed ​​is calculated and provided in real time by the upstream process control computer L2 system based on the chemical composition, thickness, and target cooling rate of the steel.

[0039] The method is implemented by a DCS distributed control system or a PLC controller, the system comprising:

[0040] Speed ​​sensing module: used to acquire the actual speed of the steel plate in real time;

[0041] Data communication module: used to interact with the L2 process computer to obtain the DFlow_DSpeed ​​coefficient and the original set flow rate;

[0042] Compensation calculation module: Embedded in the mpTrack process of the controller, it is used to execute the corresponding algorithms in each step;

[0043] Control output module: Used to send the adjusted flow command to the actuator.

[0044] The following example uses the cooling control of a 25mm thick Q345B steel plate: Cooling process target: starting cooling temperature (750±15)℃, final cooling temperature (550±20)℃, target cooling rate 14℃ / s.

[0045] Equipment configuration: Water spray cooling is performed using manifolds in three cooling zones: A, B, and C.

[0046] Parameter configuration:

[0047] σ=0.02;

[0048] C_ref=10℃ / s; C_target=14℃ / s;

[0049] C-zone manifold: Min_Flow = 150L / s, Max_Flow = 280L / s;

[0050] The steel plate enters the cooling zone, with the head passing through zones A and B in sequence. When the head of the steel plate enters the hot straightener, the tail is still in zone C. The straightener bites the steel at a speed of 1.02 m / s, causing the actual speed V_act of the entire steel plate to drop sharply to 1.02 m / s.

[0051] Please see Figure 1-2 The implementation architecture of the mpTrack process, which performs the following operations at a fixed 200ms interval:

[0052] Based on the above process parameters, the S1 and L2 systems calculate and issue the following: V_set = 1.29 m / s, Original_Flow (C zone) = 200 L / s; ΔV = V_set - V_act = 1.29 - 1.02 = 0.27 m / s

[0053] S2, DFlow_DSpeed=0.976 (meaning: for every 0.1m / s decrease in velocity, the flow rate needs to be reduced by approximately 0.0976L / s to maintain thermal balance).

[0054] S3. Calculate K = 1.0 + (25 × 0.02 × 14 / 10) = 1.0 + 0.7 = 1.7. After limiting: 1.7 > 1.5, therefore the final K = 1.5.

[0055] Then calculate flowTrim=△V×DFlow_DSpeed×K=0.27×0.976×1.5=0.395; this exceeds the limit range of [-0.1, 0.1], so the value is -0.1. The negative sign is because △V is a positive value, and the flow needs to be reduced.

[0056] S4. Calculate the new flow rate New_Flow = 200 × (1 - 0.10) = 180 L / s, which is within the range of [150, 280].

[0057] S5. Adjust the flow rate of the manifold in Zone C from 200L / s to 180L / s.

[0058] Subsequently, the steel plate was fully bitten into the straightening machine, and the speed rebounded to 1.32 m / s. At this time, steps S1 to S5 were repeated again. △V = 1.29 - 1.32 = -0.03 m / s. The negative deviation indicates that the actual speed is higher than the set value. flowTrim = -0.03 × 0.976 × 1.5 = -0.044. Since it is within the limit range of [-0.1, 0.1], the value is taken as -0.044. New_Flow = 200 × (1 - 0.044) = 191 L / s. The system adjusts the flow rate of the manifold in area C to 191 L / s.

[0059] Once the tail of the steel plate leaves zone C, the system automatically stops flow compensation for that zone.

[0060] In this embodiment, the flow rate in zone C dynamically decreases to 180 L / s as it passes through the tail of the steel plate, effectively compensating for the extended cooling time. The uniformity of the final cooling temperature of the entire plate is greatly improved: 536℃ at the head, 566℃ in the middle, and 545℃ at the tail, with a maximum temperature difference of only 30℃, fully meeting the process requirements (550±20℃). The plate shape is straight, requiring no straightening or re-straightening.

[0061] Example 2

[0062] This embodiment uses the cooling control of a 12mm thick Q345B steel plate as an example:

[0063] Model parameters are sent out:

[0064] Set the speed V_set = 2.1 m / s.

[0065] The original flow rate setting for area C was 185L / s.

[0066] The flow-velocity coefficient DFlow_DSpeed ​​= 0.65;

[0067] System configuration parameters: C-zone manifold Min_Flow=120L / s, Max_Flow=250L / s

[0068] σ=0.02, C_ref=10℃ / s.

[0069] When the tail of the steel plate enters zone C, the encoder measures the actual speed V_act = 1.85 m / s. The calculated speed deviation is: ΔV = V_set - V_act = 2.1 - 1.85 = 0.25 m / s.

[0070] K = 1.0 + (12 × 0.02 × 25 / 10) = 1.6, exceeding the limit of 1.5, so the value is 1.5;

[0071] flowTrim = 0.25 × 0.65 × 1.5 = 0.24375, which exceeds the range of [-0.1, 0.1], so the value should be -0.1.

[0072] New_Flow = 185 × (1 - 0.10) = 185 × 0.9 = 166.5 L / s, which is within the range of [120, 250]. Therefore, the flow rate of the manifold in area C is adjusted from 185 L / s to 166.5 L / s.

[0073] When the steel plate is fully bitten into the straightening machine and the speed changes, New_Flow is recalculated according to the above steps and parameters based on the actual speed. The final New_Flow value is then sent to the C-zone manifold for corresponding adjustments.

Claims

1. A method for compensating the cooling of a steel sheet based on the dynamic coupling of the velocity-flow rate, characterized in that: Includes the following steps: S1. Real-time acquisition of the set speed V_set and actual running speed V_act of the steel plate, and calculation of the speed deviation ΔV, ΔV=V_set-V_act; S2. Obtain the flow-velocity relationship coefficient DFlow_DSpeed ​​calculated by the cooling model; S3. Based on the speed deviation and the relationship coefficient, a flow compensation ratio flowTrim is calculated, flowTrim=△V×DFlow_DSpeed; S4. Apply the flow compensation ratio to the original set flow Original_Flow to generate a new flow set value New_Flow, New_Flow = Original_Flow × (1 + flowTrim), where Original_Flow is the set flow issued by the original cooling model. S5. The new flow rate setting value is sent to the execution unit of the cooling manifold to achieve dynamic adjustment of the flow rate; In step S3, when calculating the flow compensation ratio flowTrim, a configurable gain coefficient K is introduced to adjust the sensitivity of the compensation: flowTrim = ΔV × DFlow_DSpeed ​​× K. The gain coefficient K = 1 + (H_act × σ × C_target / C_ref), Where H_act is the actual thickness of the steel plate, σ is the thickness influence factor, C_target is the target cooling rate, and C_ref is the reference cooling rate constant; Limit K to a range of [0.8, 1.5].

2. The steel plate cooling compensation control method based on speed-flow dynamic coupling according to claim 1, characterized in that: The calculated flow compensation ratio is limited to a safe range of [-M, +M], where M≤0.

1.

3. The steel plate cooling compensation control method based on velocity-flow dynamic coupling according to claim 1, characterized in that: In step S4, New_Flow is compared and constrained with the preset manifold flow range [Min_Flow, Max_Flow] to ensure that the output value does not exceed the device limit.

4. The steel plate cooling compensation control method based on speed-flow dynamic coupling according to claim 1, characterized in that: In step S2, the flow-velocity relationship coefficient DFlow_DSpeed ​​is calculated and provided in real time by the upstream process control computer L2 system based on the chemical composition, thickness, and target cooling rate of the steel.

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