Dynamic partition cooling plate shape control method for medium-thickness plate heat treatment NAC process

Abstract

The invention discloses a dynamic partition cooling plate shape control method for a medium-thickness plate heat treatment NAC process, and belongs to the technical field of medium-thickness plate heat treatment. A dynamic partition cooling plate shape control method for a medium-thickness plate heat treatment NAC technology comprises the following steps that in the initial stage of the medium-thickness plate heat treatment NAC technology, a normal state nozzle set is opened through a control system, and cooling operation is carried out according to preset parameters; comparing with a preset standard; if the plate shape deviation of the medium-thickness plate exceeds the preset standard, the control system automatically judges that the lower surface of the medium-thickness plate is insufficient in cooling, the dynamic nozzle set is started, and the nozzle flow is dynamically adjusted; through directional and adjustable cooling capacity compensation provided by the dynamic nozzle group, the cooling rate difference between the upper surface and the lower surface is effectively reduced or even eliminated, and the residual stress unevenness caused by the cooling rate difference is obviously reduced, so that the downward bending amount of the head of the steel plate discharged from the furnace is stably controlled within the range of less than or equal to 4mm from 8-12mm in the traditional process, the unevenness of the whole plate shape is greatly improved, and the production efficiency is improved. And the plate shape qualification rate of the medium-thickness plate is increased by 20%-35%.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment technology for medium and heavy plates, and particularly relates to a dynamic partitioned cooling plate shape control method for the NAC process of heat treatment of medium and heavy plates. Background Technology

[0002] In steel production, controlled cooling (NAC) after heat treatment of medium and heavy plates is a key process that determines the final microstructure and properties of the product. Traditional NAC processes typically control the cooling rate and uniformity of the steel plate by adjusting the water flow ratio between the upper and lower main nozzle groups (referred to as "water ratio"), the total cooling water flow, and the running speed of the conveyor rollers (roller speed).

[0003] However, this traditional process has significant technical drawbacks: the cooling water sprayed from the upper nozzle easily forms a stagnant water film (water accumulation layer) on the steel plate surface. This water film significantly enhances the heat exchange efficiency of the upper surface, resulting in a cooling rate on the upper surface that is much higher than that on the lower surface. Even when attempts are made to balance the cooling rate by adjusting the water ratio (such as increasing the proportion of water in the lower nozzle), the inherent difference in cooling rates between the upper and lower surfaces is difficult to effectively eliminate due to the maximum flow capacity of the lower nozzle water supply pipeline (i.e., when the water volume in the lower nozzle has reached its limit) and the physical limitations of the water film effect itself. This asymmetry in cooling rate generates uneven temperature gradients and thermal stress within the steel plate, leading to uneven residual stress distribution after cooling. Macroscopically, this manifests as a noticeable downward bending of the steel plate ("knocking") and an overall uneven plate shape (such as waviness, warping, etc.) after the steel plate exits the furnace. These plate shape defects not only affect the product's appearance quality but also severely reduce the pass rate of subsequent processing and customer satisfaction.

[0004] Some improvements have been attempted in the prior art. For example, patent document (CN101781700A - A high-pressure cooling device and cooling method for a steel plate roll-type quenching machine) proposes to improve cooling symmetry by symmetrically adjusting the positions of the upper and lower nozzles and the roller gap. However, such methods have failed to effectively solve the core physical problem of local abnormal increase in cooling rate caused by water layer on the upper surface. Therefore, they have limited effect on eliminating plate shape defects such as "knocking" and may introduce new risks of uneven cooling. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a dynamic partitioned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates.

[0006] To achieve the above objectives, the invention employs the following technical solution: a dynamic zoned cooling plate shape control method for the NAC heat treatment process of medium-thick plates, comprising a conveyor roller conveyor and a normally arranged nozzle group symmetrically arranged vertically along the roller conveyor gap, wherein a dynamic nozzle group is provided on the lower surface area of ​​the conveyor roller conveyor, and the control method includes the following steps: In the initial stage of the NAC process for heat treatment of medium and heavy plates, the normal nozzle group is activated by the control system, and cooling operation is carried out according to the preset parameters. After the medium-thick plate has completed its initial cooling, a detection device is used to acquire the downward bending data and unevenness data of the plate head in real time, and transmit the data to the control system. The control system receives downbend data and unevenness data and compares them with preset standards; If the shape deviation of the medium-thick plate exceeds the preset standard, the control system automatically determines that the lower surface of the medium-thick plate is not cooled enough, immediately activates the dynamic compensation cooling mode, starts the dynamic nozzle group, and dynamically adjusts the nozzle flow rate. The control system dynamically adjusts the reduction of the roller speed according to the thickness of the medium-thick plate and the target cooling rate to ensure that the residence time of the medium-thick plate in the compensation cooling zone is optimal. The testing device retests the medium-thick plate after dynamic compensation cooling. Based on the new test results, the control system automatically fine-tunes the flow rate of the dynamic nozzle group or the roller speed until the plate shape reaches the preset standard.

[0007] By adopting the above technical solution and using dynamic nozzle group to compensate for cooling, the problem of inconsistent cooling rates between the upper and lower surfaces in the traditional NAC process can be effectively solved, and the uneven residual stress can be significantly reduced. As a result, the downward bending of the steel plate head after exiting the furnace can be stably controlled from 8-12mm in the traditional process to within ≤4mm, the overall plate shape unevenness is greatly improved, and the plate shape qualification rate is increased by 20%~35%.

[0008] Optionally, the water supply pipeline of the dynamic nozzle group is designed in parallel with the water supply pipeline of the normal nozzle group, and the flow rate can be adjusted independently without being limited by the flow rate of the normal nozzle group.

[0009] By adopting the above technical solution and through the independent water supply pipeline design, the dynamic nozzle group can independently adjust the flow rate according to actual needs, avoiding the problems of insufficient or excessive cooling caused by water supply pipeline limitations in traditional processes.

[0010] Optionally, the flow rate adjustment range of the dynamic nozzle group is usually set to 20% to 40% of the total water flow rate of the normal nozzle group. The specific flow rate value is dynamically determined based on the key parameters of the medium and heavy plate, including but not limited to steel grade, thickness, target cooling rate curve, measured plate shape deviation, and conventional cooling parameters.

[0011] By adopting the above technical solution and dynamically adjusting the flow rate, personalized adjustments can be made for different steel grades, thicknesses and cooling targets, avoiding the uneven cooling problem caused by fixed flow rate settings in traditional processes, thereby achieving precise control of "one steel, one policy".

[0012] Optionally, the detection device includes a laser level.

[0013] By adopting the above technical solution and using a laser leveling instrument as a detection device, the downward bending data and unevenness data of medium and thick plates can be obtained in real time and accurately, providing accurate feedback information for the control system and ensuring the accuracy and real-time performance of cooling control.

[0014] Optionally, the reduction in roller speed is 5% to 15% of the roller speed under normal cooling.

[0015] By adopting the above technical solution, the roller speed reduction is dynamically adjusted according to the thickness of the medium-thick plate and the target cooling rate, so that the medium-thick plate stays in the compensation cooling zone for a sufficient time to achieve the best cooling effect.

[0016] Optionally, the nozzles of the dynamic nozzle group are arranged in a matrix, and the nozzles of the dynamic nozzle group adopt a variable orifice design, which automatically adjusts the nozzle orifice size according to the cooling requirements.

[0017] By adopting the above technical solution, the matrix-arranged nozzles can cover the entire lower surface, and the variable orifice design can adjust the nozzle orifice diameter according to different cooling requirements, further improving the uniformity and precision of cooling.

[0018] Optionally, the control system includes a data acquisition module, a data processing module, a control execution module, and a feedback adjustment module; the data acquisition module is used to acquire data transmitted by the detection device; the data processing module receives the data transmitted by the data acquisition module, performs data comparison, and transmits instructions; the control execution module receives the instructions transmitted by the data processing module to control the nozzle group and roller speed for adjustment; the feedback adjustment module receives secondary data from the detection device, generates fine-tuning parameters, and transmits the fine-tuning parameters to the control execution module.

[0019] By adopting the above technical solution, the data acquisition module collects the data transmitted by the detection device, the data processing module compares and analyzes the data, the control execution module controls the adjustment of the nozzle group and roller speed, and the feedback adjustment module fine-tunes the parameters according to the new detection results, forming a closed-loop control system to achieve comprehensive monitoring and dynamic adjustment of the cooling process, ensuring the accuracy and stability of cooling control.

[0020] Optionally, the activation condition for the dynamic compensation cooling mode is that the downward bending amount of the head of the medium-thick plate is greater than 6mm or the unevenness exceeds 3mm.

[0021] By adopting the above technical solution, it is ensured that compensatory cooling can be activated in time when the plate shape deviation exceeds the preset standard, so as to avoid further deterioration of the plate shape defect. At the same time, by setting clear activation conditions, the control system can quickly respond to the plate shape deviation and activate the dynamic compensatory cooling mode in time, so as to ensure the timeliness and effectiveness of the cooling process.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. By compensating for the directional and adjustable cooling capacity provided by the dynamic nozzle group, the difference in cooling rate between the upper and lower surfaces is effectively reduced or even eliminated, significantly reducing the resulting uneven residual stress. As a result, the downward bending of the steel plate head after exiting the furnace is stably controlled from 8-12mm in the traditional process to within ≤4mm, the overall plate shape unevenness is greatly improved, and the plate shape qualification rate of medium and thick plates is increased by 20%~35%.

[0023] 2. The opening and flow rate adjustment of the dynamic nozzle group are highly targeted and flexible, which can adapt to the personalized needs of different steel grades, thicknesses and cooling targets, and achieve precise control of "one steel, one policy", avoiding the problem of uneven cooling caused by fixed flow rate settings in traditional processes.

[0024] 3. The control system includes data acquisition, data processing, control execution, and feedback adjustment modules. These modules work together to form a closed-loop control system, ensuring the accuracy and stability of cooling control and further improving the level of automation and intelligence in production. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the nozzle assembly cooling structure of the present invention; Figure 2 This is a schematic diagram of the control method of the present invention.

[0026] In the diagram: 1. Conveyor roller; 2. Normal nozzle group; 21. Upper spray zone A; 22. Lower spray zone A; 23. Upper spray zone B; 24. Lower spray zone B; 3. Dynamic nozzle group; 4. Medium and thick plate. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] like Figure 1—2 As shown in Example 1, the specific scheme is as follows: A dynamic partitioned cooling plate shape control method for the NAC process of medium and thick plate heat treatment includes a conveyor roller 1 and a normal nozzle group 2 symmetrically arranged vertically along the roller gap of the conveyor roller 1. The normal nozzle group 2 includes an upper spray zone A 21, a lower spray zone A 22, an upper spray zone B 23, and a lower spray zone B 24. The lower surface area of ​​the conveyor roller 1 is provided with a dynamic nozzle group 3. The control method includes the following steps: In the initial stage of the NAC heat treatment process for medium and heavy plates 4, the normal nozzle group 2 is activated in the control system. The normal nozzle group 2 sprays above and below the conveyor roller 1 and performs cooling operation according to preset parameters, including the initial water ratio (e.g., 1:2.5), total flow rate and roller speed. The dynamic nozzle group 3 does not participate in the normal cooling process and is only activated to compensate for the cooling rate of the lower surface. The water supply pipeline of the dynamic nozzle group 3 and the water supply pipeline of the normal nozzle group 2 are designed in parallel and can independently adjust the flow rate without being limited by the flow rate of the normal nozzle group 2. After the medium-thick plate 4 has completed its initial cooling, a detection device is used to acquire the downward bending data and unevenness data of the head of the medium-thick plate 4 in real time, and transmit the data to the control system. The detection device includes a laser leveling instrument. The control system receives downbend data and unevenness data and compares them with preset standards; If the shape of the medium-thick plate 4 meets the preset standard, then the existing preset parameters are maintained and used for cooling of subsequent steel plates of the same type. If the shape deviation of the medium-thick plate 4 exceeds the preset standard, the control system automatically determines that the lower surface of the medium-thick plate 4 is not cooled enough and immediately activates the dynamic compensation cooling mode. The activation conditions of the dynamic compensation cooling mode are that the downward bending amount of the head of the medium-thick plate 4 is greater than 6mm or the unevenness is greater than 3mm. The dynamic nozzle group 3 is started and the nozzle flow rate is dynamically adjusted. The flow rate adjustment range of the dynamic nozzle group 3 is usually set to 20% to 40% of the total water flow rate of the normal nozzle group 2. The specific flow rate value is dynamically determined based on the key parameters of the medium-thick plate 4, including but not limited to steel grade, thickness, target cooling rate curve, measured shape deviation, and conventional cooling parameters (for example, the larger the thickness or the higher the target cooling rate, the greater the required compensation flow rate may be; the greater the measured downward bending amount, the greater the compensation flow rate also needs to be). The nozzles of the dynamic nozzle group 3 are arranged in a matrix. The nozzles of the dynamic nozzle group 3 adopt a variable orifice design and automatically adjust the nozzle orifice size according to the cooling requirements. The control system dynamically adjusts the reduction of the roller speed according to the thickness of the medium-thick plate 4 and the target cooling rate. The reduction of the roller speed is 5% to 15% of the roller speed under normal cooling. This ensures that the medium-thick plate 4 has the optimal residence time in the compensation cooling zone, and ensures that the increased cooling water flow has enough time to act on the lower surface of the medium-thick plate 4, thereby improving its cooling rate and striving to balance it with the cooling rate of the upper surface. At the same time, reducing the roller speed is the key to ensuring the compensation effect. Otherwise, simply adding water may lead to the overall temperature of the steel plate being too low or the uneven cooling being aggravated. The testing device retests the medium-thick plate 4 after dynamic compensation cooling. The control system automatically fine-tunes the flow rate or roller speed of the dynamic nozzle group 3 based on the new test results until the plate shape of the medium-thick plate 4 reaches the preset standard. Establish an experience database to provide more accurate initial compensation parameter suggestions for subsequent production of similar medium and heavy plates.

[0030] The control system includes a data acquisition module, a data processing module, a control execution module, and a feedback adjustment module; the data acquisition module is used to acquire data transmitted by the detection device; the data processing module is used to compare and analyze the data; the control execution module is used to control the adjustment of the nozzle group and the roller speed; and the feedback adjustment module is used to fine-tune the parameters based on new detection results. The data acquisition module is responsible for collecting downbending data and unevenness data of the head of the medium-thick plate from the detection device in real time, and performing preliminary screening and formatting of the collected downbending data and unevenness data to facilitate further processing by the data processing module. After processing, the downbending data and unevenness data are transmitted to the data processing module. The data processing module receives the downward bending data and unevenness data transmitted from the data acquisition module, compares them with the preset plate shape standard, and if the plate shape meets the preset standard, it generates an instruction to maintain the existing preset parameters and transmits the instruction to the control execution module. If the plate shape deviation exceeds the preset standard (such as the downward bending amount of the head is greater than 6mm or the unevenness is greater than 3mm), it calculates the required compensation flow rate and roller speed reduction based on the key parameters of medium and heavy plate 4 (such as steel grade, thickness, target cooling rate curve, measured plate shape deviation, conventional cooling parameters, etc.), transmits the calculated compensation parameters (such as compensation flow rate, roller speed reduction, etc.) to the control execution module, and stores the relevant data in the experience database to provide a reference for the subsequent production of similar steel plates. The control execution module receives instructions transmitted by the data processing module. If the instruction is to maintain the existing preset parameters, the water flow rate, roller speed and other parameters of the normal nozzle group 2 will remain unchanged. If the instruction is to start the dynamic compensation cooling mode, the dynamic nozzle group 3 will be activated immediately. The water flow rate of the dynamic nozzle group 3 will be adjusted according to the compensation flow rate calculated by the data processing module. At the same time, the roller speed will be adjusted according to the calculated reduction in roller speed. The feedback adjustment module receives the head bending and unevenness data of the medium-thick plate 4 detected again by the detection device, compares the new detection results with the preset standard, and if the plate shape still does not meet the preset standard, it calculates the flow rate or roller speed of the dynamic nozzle group 3 that needs further adjustment based on the deviation, and transmits the calculated fine-tuning parameters to the control execution module. The control execution module further adjusts the nozzle group and roller speed according to the fine-tuning parameters, and repeats the above process until the plate shape of the medium-thick plate 4 meets the preset standard, ensuring the stability and consistency of the cooling effect. The final adjustment parameters and detection results are stored in the experience database to provide more accurate initial compensation parameter suggestions for the subsequent production of similar steel plates.

[0031] Example 2: In the NAC process of heat treatment for medium and heavy plates, for DH36-HY marine engineering steel plates with a thickness of 16mm, it is necessary to ensure that the plate shape after cooling meets the delivery requirements. However, under the conventional cooling mode, the steel plate is prone to the problem of the head bending amount exceeding the tolerance standard. Therefore, a dynamic zoned cooling plate shape control method is adopted for optimization. The specific process is as follows: 1. For the standard cooling mode (initial parameter settings) In the initial stage of the NAC heat treatment process for medium and heavy plates, the normal nozzle group 2 is activated by the control system for cooling operations, namely, the upper spray zone 21 and the lower spray zone 22 of A are used for cooling operations, while the upper spray zone 23 and the lower spray zone 24 of B do not participate in the cooling operation. The control system presets the parameters for the normal nozzles, including the water flow rate. The water flow rate of the upper spray zone 21 of A is 200 m³ / h, the water flow rate of the lower spray zone 22 of A is 500 m³ / h, the initial water ratio is about 1:2.5, the total water flow rate is 700 m³ / h, and the roller speed is set to 0.78 m / s. During this stage, the dynamic nozzle group 3 is closed and does not participate in the cooling process.

[0032] 2. Plate shape detection After the steel plate has completed its initial cooling, a laser leveling instrument is used to acquire the downward bending data and unevenness data of the four heads of the medium-thick plate in real time. The detection device transmits the acquired data to the control system.

[0033] 3. Control system processing and dynamic compensation cooling mode (parameter adjustment).

[0034] The control system's data acquisition module collects real-time data on the downward bending and unevenness of the steel plate head from the detection device, performs preliminary screening and formatting, and then transmits the data to the data processing module. The data processing module compares the received data with the preset plate shape standard and finds that after the steel plate is cooled to room temperature after being taken out of the furnace, the downward bending of the steel plate head reaches 12mm (with 2m as the measurement reference length), which significantly exceeds the plate shape tolerance standard required for this product (downward bending of the head ≤ 8mm / 2m), and determines that the lower surface of the medium-thick plate 4 is not cooled enough.

[0035] The data processing module calculates the required compensation flow rate and roller speed reduction based on the key parameters of the medium-thick plate 4 (steel grade DH36-HY, thickness 16mm, combined with the target cooling rate curve, measured plate shape deviation, conventional cooling parameters, etc.). After calculation, the total water flow rate of the dynamic nozzle group 3 is set to 250m³ / h, which is within the flow rate adjustment range of the dynamic nozzle group 3. Simultaneously, the roller speed is reduced to 0.73 m / s, a reduction of approximately 6.4%. Within the range of roller speed reduction, the residence time of the medium-thick plate 4 in the compensation cooling zone is optimized, and the increased cooling water flow has sufficient time to act on the lower surface of the medium-thick plate 4, thereby improving its cooling rate and bringing it closer to the cooling rate of the upper surface. The data processing module transmits the calculated compensation parameters (compensation flow rate, roller speed reduction, etc.) to the control execution module and stores the relevant data in the experience database.

[0036] 4. Verification of compensation effect and feedback adjustment After cooling subsequent 16mm DH36-HY steel plates of the same batch using the above compensation parameters, the laser leveling instrument inspects the steel plates again, acquiring new head bending and unevenness data, and transmitting them to the control system. The feedback adjustment module of the control system receives the new test results, compares them with the preset standard, and finds that the head bending of the steel plate is significantly reduced to ≤5mm / 2m, meeting the delivery shape requirement of ≤8mm / 2m. The overall straightness is good, and the plate shape meets the preset standard. Therefore, there is no need to further fine-tune the flow rate or roller speed of the dynamic nozzle group 3. The final adjustment parameters and test results are stored in the experience database to provide more accurate initial compensation parameter suggestions for the subsequent production of similar steel plates.

[0037] Example 3: In the NAC heat treatment process for medium and heavy plates, for DH36-HY marine engineering steel plates with a thickness of 32mm, in order to ensure that the plate shape meets the delivery requirements after cooling, and considering that the conventional cooling mode easily causes the downward bending of the steel plate head to exceed the tolerance standard, a dynamic zone cooling plate shape control method is adopted for optimization. The specific process is as follows: 1. For the standard cooling mode (initial parameter settings) In the initial stage of the NAC heat treatment process for medium and thick plates, the normal nozzle group 2 is activated by the control system to carry out cooling operations. That is, the upper spray zone 21, the lower spray zone 22, the upper spray zone 23, and the lower spray zone 24 of B all participate in the cooling operation. The control system presets the parameters for each area nozzle group. The water flow rate in spray zone 21 (A upper) is approximately 200 m³ / h, and the water flow rate in spray zone 22 (A lower) is approximately 480 m³ / h, with an initial water ratio of approximately 1:2.4. The water flow rate in spray zone 23 (B upper) is approximately 240 m³ / h, and the water flow rate in spray zone 24 (B lower) is approximately 600 m³ / h, with an initial water ratio of approximately 1:2.5. The total water flow rate is 1520 m³ / h, and the roller conveyor speed is set to 0.68 m / s. During this stage, the dynamic nozzle group 3 is closed and does not participate in the cooling process.

[0038] 2. Plate shape detection After the steel plate is taken out of the furnace, a detection device is used to obtain the downward bending data and unevenness data of the steel plate head in real time. The detection found that the downward bending of the steel plate head reached 10mm / 2m.

[0039] 3. Control system processing and dynamic compensation cooling mode (parameter adjustment) The control system's data acquisition module collects real-time data on the downward bending and unevenness of the steel plate head from the detection device, performs preliminary screening and formatting, and then transmits the data to the data processing module. The data processing module compares the received data with the preset plate shape standard and finds that the plate shape tolerance exceeds the requirement for the thickness of the steel plate (e.g., ≤6mm / 2m), and determines that the cooling of the lower surface of the steel plate is insufficient. The data processing module calculates the required compensation flow rate and roller speed reduction based on the key parameters of the medium-thick plate 4 (steel grade DH36-HY, thickness 32mm, combined with the target cooling rate curve, measured plate shape deviation, and conventional cooling parameters). After calculation, the dynamic nozzle group 3 is activated, and its water flow rate is set to 400m³ / h. The roller speed is simultaneously reduced to 0.62m / s to ensure optimal residence time of the medium-thick plate 4 in the compensation cooling zone. The increased cooling water flow rate has sufficient time to act on the lower surface of the medium-thick plate 4, improving its cooling rate and bringing it closer to the cooling rate of the upper surface. The data processing module transmits the calculated compensation parameters to the control execution module and stores the relevant data in the experience database.

[0040] 4. Verification of compensation effect and feedback adjustment After cooling subsequent 32mm DH36-HY steel plates of the same batch using compensation parameters, the steel plates were inspected again to obtain new head bending and unevenness data. The inspection results showed that the head bending amount of the steel plate was ≤3mm / 2m, and the overall unevenness was ≤3mm / 2m. The plate shape quality was excellent and fully met the delivery requirements. Therefore, there was no need to further fine-tune the flow rate or roller speed of the dynamic nozzle group 3. The final adjustment parameters and inspection results were stored in the experience database to provide more accurate initial compensation parameter suggestions for the subsequent production of similar steel plates.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for dynamic zoned cooling plate shape control in the NAC heat treatment process of medium-thick plates, comprising a conveyor roller conveyor and a group of normally arranged nozzles symmetrically arranged vertically along the roller conveyor gap, wherein a dynamic nozzle group is provided on the lower surface region of the conveyor roller conveyor, characterized in that... The control method includes the following steps: In the initial stage of the NAC heat treatment process for medium and thick plates, the normal nozzle group is activated by the control system to carry out cooling operations according to preset parameters. After the medium-thick plate has completed its initial cooling, a detection device is used to acquire the downward bending data and unevenness data of the head of the medium-thick plate in real time, and transmit the data to the control system. The control system receives downbend data and unevenness data, and compares them with preset standards; If the shape deviation of the medium-thick plate exceeds the preset standard, the control system automatically determines that the lower surface of the medium-thick plate is not cooled enough, immediately activates the dynamic compensation cooling mode, starts the dynamic nozzle group, and dynamically adjusts the nozzle flow rate. The control system dynamically adjusts the reduction in roller speed based on the thickness of the medium-thick plate and the target cooling rate to ensure that the medium-thick plate has the optimal residence time in the compensation cooling zone. The detection device re-detects the medium-thick plate after dynamic compensation cooling. The control system automatically fine-tunes the flow rate or roller speed of the dynamic nozzle group based on the new detection results until the plate shape of the medium-thick plate reaches the preset standard.

2. The dynamic zoned cooling plate shape control method for the NAC process of medium-thick plate heat treatment according to claim 1, characterized in that: The water supply pipeline of the dynamic nozzle group is designed in parallel with the water supply pipeline of the normal nozzle group, and the flow rate can be adjusted independently without being limited by the flow rate of the normal nozzle group.

3. The dynamic zoned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates according to claim 1, characterized in that: The flow rate adjustment range of the dynamic nozzle group is usually set to 20% to 40% of the total water flow rate of the normal nozzle group. The specific flow rate value is dynamically determined based on the key parameters of the medium and thick plate, including but not limited to steel grade, thickness, target cooling rate curve, measured plate shape deviation, and conventional cooling parameters.

4. The dynamic partitioned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates according to claim 1, characterized in that: The detection device includes a laser level.

5. The dynamic zoned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates according to claim 1, characterized in that: The reduction in roller speed is 5% to 15% of the roller speed under normal cooling.

6. The dynamic zoned cooling plate shape control method for the NAC process of medium-thick plate heat treatment according to claim 1, characterized in that: The nozzles of the dynamic nozzle group are arranged in a matrix, and the nozzles of the dynamic nozzle group adopt a variable orifice design, which automatically adjusts the nozzle orifice size according to the cooling requirements.

7. The dynamic zoned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates according to claim 1, characterized in that: The control system includes a data acquisition module, a data processing module, a control execution module, and a feedback adjustment module. The data acquisition module is used to acquire data transmitted by the detection device. The data processing module receives the data transmitted by the data acquisition module, performs data comparison, and transmits instructions. The control execution module receives instructions transmitted by the data processing module to control the nozzle group and roller speed for adjustment. The feedback adjustment module receives secondary data from the detection device, generates fine-tuning parameters, and transmits the fine-tuning parameters to the control execution module.

8. The dynamic partitioned cooling plate shape control method for the NAC process of heat treatment of medium and thick plates according to claim 1, characterized in that: The activation conditions for the dynamic compensation cooling mode are that the downward bending amount of the head of the medium-thick plate is greater than 6mm or the unevenness exceeds 5mm / m.

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