Temperature-time gradient control method for burial pit after bar rolling

Abstract

The invention relates to the technical field of bar rolling, and discloses a burial pit temperature-time gradient control method after bar rolling, which comprises the following steps: S1, burial pit pretreatment and parameter initialization, S2, bar pit entering and initial temperature regulation and control, S3, gradient cooling dynamic regulation and control, S4, stage node verification and adjustment, and S5, data recording and optimization iteration. According to the method, the structure performance is accurately controlled, through three-stage temperature gradient setting (0-4h < = 50 DEG C / h, 4-12h < = 30 DEG C / h and 12-36h < = 20 DEG C / h), real-time temperature monitoring and dynamic adjustment are combined, it is ensured that the bar is slowly and evenly cooled, internal stress and abnormal structures are reduced, the occurrence rate of the quality problems that hardness exceeds the standard and the structures are uneven is remarkably reduced (the occurrence rate can be reduced by 30% or above), and the quality of the bar is improved. According to the method, the temperature regulation and control precision is improved, and the temperature deviation in the pit can be found in time by adopting multiple layers of temperature and humidity sensors (the precision is + / -1 DEG C) and the monitoring frequency of one time every 30 minutes (the adjustment is triggered when T < real >-T < line > is greater than 10 DEG C).

Description

Technical Field

[0001] The invention relates to the technical field of bar rolling, in particular to a method for controlling the temperature-time gradient of a slow cooling pit after bar rolling. Background Art

[0002] In bar rolling production, post-rolling slow cooling is a key step in ensuring stable product structure and performance. Traditional slow cooling pit processes mostly use static insulation methods, which lack precise control of temperature changes: Temperature gradient out of control: During the slow cooling process, the graded cooling standard is not set according to the bar specifications and initial temperature. The cooling rate is often too fast or too slow, resulting in stress concentration and uneven structure inside the bar (such as network carbide precipitation, coarse grains, etc.), affecting the mechanical properties.

[0003] Monitoring and feedback lag: Relying solely on regular manual inspections to record temperature cannot capture the temperature differences between different areas in the pit in real time, and it is not associated with environmental factors such as humidity. Abnormal local temperature and humidity can easily lead to oxidation or rust on the surface of the rods.

[0004] Insufficient data utilization: The parameters of the entire slow cooling process are not systematically recorded, making it difficult to trace the root cause of quality problems and unable to optimize the process based on historical data. As a result, the slow cooling effect of bars of the same specification is poorly stable and the quality fluctuates greatly between batches.

[0005] Poor equipment coordination: The operation of equipment such as insulation layers and ventilation devices relies on experience and is not linked to temperature monitoring data. Dynamic adjustments cannot be made based on actual cooling trends, resulting in energy waste or excessively long cooling times, affecting production efficiency. Summary of the Invention

[0006] (1) Technical problems solved In response to the shortcomings of the existing technology, the present invention provides a method for controlling the temperature-time gradient of the slow cooling pit after bar rolling, which has the advantages of accurately controlling the microstructure and properties, and solves problems such as temperature gradient out of control.

[0007] (2) Technical solution In order to achieve the above-mentioned precise control of microstructure and performance, the present invention provides the following technical solutions: a temperature-time gradient control method for the slow cooling pit after bar rolling, including S1 slow cooling pit pretreatment and parameter initialization, S2 bar pit entry and initial temperature control, S3 gradient cooling dynamic control, S4 stage node verification and adjustment, and S5 data recording and optimization iteration. The S1 slow cooling pit pretreatment and parameter initialization includes S101 pit body state detection and cleaning, S102 graded temperature benchmark setting, and S103 temperature and humidity sensor deployment; Among them, S2 bar entry and initial temperature control includes S201 group entry and interval setting, S202 initial temperature recording and S203 sealing and insulation start; Among them, S3 gradient cooling dynamic control includes S301 real-time temperature monitoring and feedback, S302 cooling rate adjustment mechanism and S303 humidity control assistance; Among them, the node verification and adjustment in the S4 phase includes S401: 4h node verification, S402: 12h node verification and S403: 36h final verification; Among them, S5 data recording and optimization iteration includes S501 full-process data storage, S502 data review and regularity analysis, S503 process parameter optimization and S504 equipment performance calibration.

[0008] Preferably, the S101 pit state detection and cleaning: use an infrared thermometer to detect the temperature of the inner wall of the slow cooling pit to ensure that the initial temperature is ≤50°C; clean up the remaining debris and iron oxide in the pit, check the integrity of the insulation layer (damaged area ≤0.01㎡ needs to be repaired), and turn off the ventilation device in the pit.

[0009] Preferably, the step S102 of setting the graded temperature benchmark is as follows: according to the specifications of the rolled bar (diameter 20-100 mm) and the final rolling temperature (800-950° C.), three-level temperature gradient benchmarks are preset: First-stage gradient (0-4h): cooling rate ≤ 50℃ / h; Secondary gradient (4-12h): cooling rate ≤ 30℃ / h; Three-level gradient (12-36h): cooling rate ≤20℃ / h.

[0010] Preferably, the S103 temperature and humidity sensors are deployed as follows: 2 temperature sensors (accuracy ±1°C) and 1 humidity sensor (monitoring range 30%-60% RH) are arranged in each of the upper, middle and lower layers of the pit, with the sensor spacing ≥1.5m to ensure coverage of the bar stacking area.

[0011] Preferably, the S201 grouping and spacing setting is as follows: the rolled bars are grouped according to specifications (diameter difference ≤ 10 mm as a group), stacked in a "well" shape, and a ventilation gap of ≥ 300 mm is left between groups; bars of the same heat number are stacked together, and bars of different heat numbers are separated by insulation boards (thermal conductivity of the insulation boards ≤ 0.1 W / (m·K)).

[0012] Preferably, the initial temperature record of S202 entering the pit is: use a portable thermometer to detect the surface temperature of the rods (measure 3 points per bundle), record the average value as the initial temperature (T0), and when T0>950℃, turn on the circulating fan in the pit (wind speed 0.5m / s) to cool down for 30 minutes and then turn it off.

[0013] Preferably, the S203 sealing and insulation is started: after covering the pit cover, the edge sealing device is started (sealing gap ≤ 5mm), and the thickness of the insulation layer is automatically adjusted according to the initial temperature: when T0 ≥ 900℃, double-layer insulation (total thickness 150mm) is enabled, and when T0 < 900℃, single-layer insulation (thickness 80mm) is enabled.

[0014] Preferably, the real-time temperature monitoring and feedback in S301 is as follows: temperature data of sensors on each layer is collected every 30 minutes, the difference between the average temperature (Tactual) and the theoretical temperature (Ttheoretical) of the corresponding gradient is calculated, and when |Tactual - Ttheoretical|>10°C, the adjustment is triggered; S302 cooling rate adjustment mechanism: When Tactual>Tactual (cooling too slowly): open the heat dissipation windows on the sides of the pit (the opening area is adjusted in proportion to the over-temperature value, increasing the opening area by 10% for every 10°C over-temperature), and simultaneously start the bottom ventilation (wind speed 0.3-0.8m / s adjustable); When Tactual < Tactual (temperature drops too quickly): close the heat dissipation window and add a temporary insulation layer (add 50mm thickness for every 10℃ drop in temperature), start the pit heating device (power 5-15kW adjustable) until the temperature difference is ≤5℃, then turn it off; S303 Humidity control assistance: When the humidity in the pit is greater than 60% RH, start the dehumidification device (dehumidification rate ≥ 2kg / h) to maintain the humidity in the range of 40%-50% RH to avoid oxidation and rust on the surface of the rods.

[0015] Preferably, the S401: 4h node verification: when reaching the end point of the first-level gradient, the core temperature of the bar is detected (using an insertion thermometer, measuring one point per bundle). If the temperature difference between the core and the surface is greater than 80°C, the first-level gradient time is extended by 2h, and the cooling rate is reduced to 30°C / h. S402: 12h node verification: After the second-level gradient is completed, samples are taken to test the hardness of the bars (3 samples are taken for each batch). If the hardness deviation exceeds the standard value by ±5HB, the third-level gradient cooling rate is adjusted (for every 1HB of deviation, the rate is reduced by 1℃ / h); S403: 36h final verification: 1h before the end of slow cooling, the overall temperature of the bar is ≤150℃ and the temperature difference at each point is ≤20℃, which is considered qualified; otherwise, the slow cooling time is extended (2h for every 10℃ increase).

[0016] Preferably, the S501 full-process data storage includes: recording the pit entry time, the initial temperature of the bar (surface and core), the average temperature in the pit at each time point (0h, 4h, 12h, 36h), the temperature difference at different positions, the cooling rate adjustment record, the humidity change data, the operating status information of the insulation layer and the ventilation device, and at the same time associating the specifications of the corresponding batch of bars and the basic information of the rolling process parameters. All data are stored in an encrypted format with a retention period of not less than 1 year, and are regularly backed up to an independent storage device to ensure data traceability; S502 Data Review and Pattern Analysis: Summarize and analyze slow cooling data weekly, calculate the deviation rate between the actual cooling curve and the theoretical gradient for different specifications and initial temperatures, and count the frequency and causes of abnormal bar quality (such as excessive hardness and uneven structure) caused by improper temperature control. Target high-frequency deviation patterns (such as excessively rapid cooling of a certain specification of bar during the 12-36h period) to establish a specialized analysis model and identify influencing factors (such as pit stacking density and insulation layer performance degradation). S503 process parameter optimization: Dynamically adjust the temperature gradient benchmark based on analysis results. For example, for bars with a diameter greater than 80mm, reduce the upper limit of the cooling rate for the secondary gradient (4-12h) from 30°C / h to 25°C / h. When the initial temperature of a batch of bars is consistently above 900°C, increase the initial ventilation speed for the primary gradient (0-4h) to 0.6m / s. The optimized parameters must be verified through three small-scale trial rollings and incorporated into the formal process specifications after confirming stable quality. S504 equipment performance calibration: Calibrate the in-pit sensor monthly based on the stored temperature data (debug or replace if the error exceeds ±2°C), check the thermal conductivity of the insulation layer (measured with a heat flow meter, and replace promptly if it exceeds the standard), ensure that the equipment status matches the process parameter requirements, and guarantee the long-term stability of the temperature control accuracy.

[0017] (3) Beneficial effects Compared with the prior art, the present invention provides a method for controlling the temperature-time gradient of the slow cooling pit after bar rolling, which has the following beneficial effects: 1. The temperature-time gradient control method for the slow cooling pit after rolling of the bar achieves precise control of microstructure and performance. By setting a three-level temperature gradient (0-4h≤50℃ / h, 4-12h≤30℃ / h, 12-36h≤20℃ / h), combined with real-time temperature monitoring and dynamic adjustment, it ensures that the bar cools down slowly and evenly, reduces internal stress and abnormal microstructure, and significantly reduces the incidence of quality problems such as excessive hardness and uneven microstructure (which can be reduced by more than 30%).

[0018] 2. A temperature-time gradient control method for the slow cooling pit after rolling the bar is adopted. This method improves the temperature control accuracy. It adopts a multi-layer temperature and humidity sensor (accuracy ±1°C) and a monitoring frequency of once every 30 minutes. It can promptly detect temperature deviations in the pit (trigger adjustment when |T actual - T rational|>10°C). Through the coordinated action of the heat dissipation window and the heating device, the temperature difference between each area is controlled within 20°C, avoiding performance fluctuations caused by local overheating or overcooling.

[0019] 3. The temperature-time gradient control method for the slow cooling pit after rolling of the bar can reduce surface quality defects. The introduction of humidity control (maintaining 40%-50% RH) and the use of heat insulation plates to separate bars of different furnace numbers can effectively reduce the risk of surface oxidation and rust, and increase the surface qualification rate of the bars to more than 98%.

[0020] 4. The temperature-time gradient control method of the slow cooling pit after rolling of the bar is adopted. This method optimizes production efficiency and cost. Through stage node verification (4h, 12h, 36h) and dynamic adjustment of the slow cooling time, it avoids invalid insulation or excessive extension of the slow cooling cycle, and shortens the slow cooling time of a single batch by about 10%-15%. At the same time, based on data review, the process parameters are optimized to reduce energy consumption (such as adjusting the power of the heating device as needed) and reduce production costs.

[0021] 5. The temperature-time gradient control method for the slow cooling pit after rolling of the bar realizes full-process quality traceability and continuous improvement. The full-process data is encrypted and stored (retention period ≥ 1 year), and the slow cooling parameters and quality correlation of each batch of bars can be traced. Through weekly data analysis and iterative process (such as lowering the cooling rate for large-size bars), the stability of the slow cooling effect is gradually improved, and the product performance compliance rate is increased to more than 95%. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] This solution provides a technical solution, specifically, a method for controlling the temperature-time gradient of the slow cooling pit after bar rolling, including the following methods: S1 slow cooling pit pretreatment and parameter initialization: S101 Pit Condition Inspection and Cleaning: Use an infrared thermometer to check the temperature of the slow cooling pit wall to ensure that the initial temperature is ≤50°C; clean the remaining debris and iron oxide scale in the pit, check the integrity of the insulation layer (damaged area ≤0.01㎡ needs to be repaired), and turn off the ventilation device in the pit; S102 Grading temperature benchmark setting: According to the specifications of the rolled bar (diameter 20-100mm) and the final rolling temperature (800-950℃), three-level temperature gradient benchmarks are preset: First-stage gradient (0-4h): cooling rate ≤ 50℃ / h; Secondary gradient (4-12h): cooling rate ≤ 30℃ / h; Level 3 gradient (12-36h): cooling rate ≤ 20℃ / h; S103 temperature and humidity sensor deployment: Two temperature sensors (accuracy ±1°C) and one humidity sensor (monitoring range 30%-60% RH) are placed on each of the upper, middle, and lower levels of the pit. The sensor spacing should be ≥1.5m to ensure coverage of the bar stacking area. S2 bar entering the pit and initial temperature control: S201 Grouping and spacing: After rolling, the bars are grouped by specification (diameter difference ≤ 10mm per group) and stacked in a "well" shape, with ventilation gaps ≥ 300mm between groups. Bars from the same heat are stacked together, and heat insulation boards are used to separate bars from different heats (thermal conductivity of the insulation boards ≤ 0.1W / (m・K)). S202 Initial temperature recording upon entering the pit: Use a portable thermometer to measure the surface temperature of the bars (measure 3 points per bundle), and record the average value as the initial temperature (T0). When T0>950°C, turn on the circulating fan in the pit (wind speed 0.5m / s) to cool down for 30 minutes, then turn it off; S203 Sealing and insulation start: After covering the pit cover, start the edge sealing device (sealing gap ≤ 5mm), and automatically adjust the thickness of the insulation layer according to the initial temperature: when T0 ≥ 900℃, start double-layer insulation (total thickness 150mm), and when T0 < 900℃, start single-layer insulation (thickness 80mm); S3 gradient cooling dynamic control: S301 real-time temperature monitoring and feedback: collects temperature data from sensors on each floor every 30 minutes, calculates the difference between the average temperature (Tactual) and the theoretical temperature (Ttheoretical) of the corresponding gradient, and triggers regulation when |Tactual - Ttheoretical|>10°C; S302 cooling rate adjustment mechanism: When Tactual>Tactual (cooling too slowly): open the heat dissipation windows on the sides of the pit (the opening area is adjusted in proportion to the over-temperature value, increasing the opening area by 10% for every 10°C over-temperature), and simultaneously start the bottom ventilation (wind speed 0.3-0.8m / s adjustable); When Tactual < Tactual (temperature drops too quickly): close the heat dissipation window and add a temporary insulation layer (add 50mm thickness for every 10℃ drop in temperature), start the pit heating device (power 5-15kW adjustable) until the temperature difference is ≤5℃, then turn it off; S303 Humidity control assistance: When the humidity in the pit is greater than 60% RH, the dehumidification device is activated (dehumidification rate ≥ 2kg / h) to maintain the humidity in the range of 40%-50% RH to prevent oxidation and rust on the surface of the rods; S4 stage node verification and adjustment: S401: 4h node verification: When reaching the end of the first-level gradient, check the core temperature of the bar (use an insertion thermometer, measure one point per bundle). If the temperature difference between the core and the surface is greater than 80°C, extend the first-level gradient time by 2h and reduce the cooling rate to 30°C / h. S402: 12h node verification: After the second-level gradient is completed, samples are taken to test the hardness of the bars (3 samples are taken for each batch). If the hardness deviation exceeds the standard value by ±5HB, the third-level gradient cooling rate is adjusted (for every 1HB of deviation, the rate is reduced by 1℃ / h); S403: 36h final verification: 1 hour before the end of slow cooling, the overall temperature of the bar is ≤150℃ and the temperature difference at each point is ≤20℃, which is considered qualified; otherwise, the slow cooling time is extended (2 hours for every 10℃ increase); S5 data recording and optimization iteration: S501 full-process data storage: records the time of entering the pit, the initial temperature of the bar (surface and core), the average temperature in the pit at each time point (0h, 4h, 12h, 36h), the temperature difference at different locations, the cooling rate adjustment record, humidity change data, the operating status information of the insulation layer and ventilation device, and at the same time associates the specifications of the corresponding batch of bars and basic information on rolling process parameters. All data is stored in an encrypted format with a retention period of no less than 1 year and is regularly backed up to an independent storage device to ensure data traceability; S502 Data Review and Pattern Analysis: Summarize and analyze slow cooling data weekly, calculate the deviation rate between the actual cooling curve and the theoretical gradient for different specifications and initial temperatures, and count the frequency and causes of abnormal bar quality (such as excessive hardness and uneven structure) caused by improper temperature control. Target high-frequency deviation patterns (such as excessively rapid cooling of a certain specification of bar during the 12-36h period) to establish a specialized analysis model and identify influencing factors (such as pit stacking density and insulation layer performance degradation). S503 process parameter optimization: Dynamically adjust the temperature gradient benchmark based on analysis results. For example, for bars with a diameter greater than 80mm, reduce the upper limit of the cooling rate for the secondary gradient (4-12h) from 30°C / h to 25°C / h. When the initial temperature of a batch of bars is consistently above 900°C, increase the initial ventilation speed for the primary gradient (0-4h) to 0.6m / s. The optimized parameters must be verified through three small-scale trial rollings and incorporated into the formal process specifications after confirming stable quality. S504 equipment performance calibration: Calibrate the in-pit sensor monthly based on stored temperature data (debug or replace if the error exceeds ±2°C), check the thermal conductivity of the insulation layer (measured with a heat flow meter, and promptly replace if it exceeds the standard), ensure that the equipment status matches the process parameter requirements, and guarantee the long-term stability of temperature control accuracy; Furthermore, this method achieves precise control of microstructure properties. By setting a three-level temperature gradient (0-4h ≤ 50℃ / h, 4-12h ≤ 30℃ / h, 12-36h ≤ 20℃ / h), combined with real-time temperature monitoring and dynamic adjustment, it ensures that the bar cools slowly and evenly, reducing internal stress and abnormal microstructure, and significantly reducing the incidence of quality problems such as excessive hardness and uneven microstructure (by more than 30%). Furthermore, this method improves temperature control accuracy. Using multi-layer temperature and humidity sensors (accuracy of ±1°C) and a 30-minute monitoring frequency, it can promptly detect temperature deviations within the pit (triggering regulation when |Tactual - Trational| > 10°C). Through the coordinated action of heat dissipation windows and heating devices, the temperature difference between each area is controlled within 20°C, avoiding performance fluctuations caused by local overheating or overcooling. Furthermore, this method reduces surface quality defects. By introducing humidity control (maintaining 40%-50% RH) and using heat shields to separate bars from different heats, the risk of surface oxidation and rust can be effectively reduced, increasing the bar surface quality rate to over 98%. Furthermore, this method optimizes production efficiency and costs. By verifying stage nodes (4 hours, 12 hours, and 36 hours) and dynamically adjusting the slow cooling time, it avoids ineffective heat preservation or excessive extension of the slow cooling cycle, shortening the slow cooling time of a single batch by approximately 10%-15%. At the same time, based on data review, process parameters are optimized to reduce energy consumption (such as adjusting the power of the heating device on demand), thereby lowering production costs. Furthermore, this method achieves full-process quality traceability and continuous improvement, with encrypted storage of full-process data (retention period ≥ 1 year), and the correlation between the slow cooling parameters and quality of each batch of bars can be traced; through weekly data analysis and iterative processes (such as lowering the cooling rate for large-size bars), the stability of the slow cooling effect is gradually improved, and the product performance compliance rate is increased to more than 95%.

[0024] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A temperature-time gradient control method for the slow cooling pit after bar rolling, including S1 slow cooling pit pretreatment and parameter initialization, S2 bar pit entry and initial temperature control, S3 dynamic control of gradient cooling, S4 stage node verification and adjustment, and S5 data recording and optimization iteration. The method is characterized by: The S1 slow cooling pit pre-processing and parameter initialization includes S101 pit body status detection and cleaning, S102 graded temperature benchmark setting and S103 temperature and humidity sensor deployment; Among them, S2 bar entry and initial temperature control includes S201 group entry and interval setting, S202 initial temperature recording and S203 sealing and insulation start; Among them, S3 gradient cooling dynamic control includes S301 real-time temperature monitoring and feedback, S302 cooling rate adjustment mechanism and S303 humidity control assistance; Among them, the node verification and adjustment in the S4 phase includes S401: 4h node verification, S402: 12h node verification and S403: 36h final verification; Among them, S5 data recording and optimization iteration includes S501 full-process data storage, S502 data review and regularity analysis, S503 process parameter optimization and S504 equipment performance calibration.

2. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S101 pit body status inspection and cleaning: use an infrared thermometer to detect the temperature of the inner wall of the slow cooling pit to ensure that the initial temperature is ≤50℃; clean up the remaining debris and iron oxide in the pit, check the integrity of the insulation layer (repair is required when the damaged area is ≤0.01㎡), and turn off the ventilation device in the pit.

3. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S102 temperature gradient benchmark setting is as follows: According to the specifications of the rolled bar (diameter 20-100 mm) and the final rolling temperature (800-950°C), three temperature gradient benchmarks are preset: First-stage gradient (0-4h): cooling rate ≤ 50℃ / h; Secondary gradient (4-12h): cooling rate ≤ 30℃ / h; Three-level gradient (12-36h): cooling rate ≤20℃ / h.

4. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S103 temperature and humidity sensor deployment: 2 temperature sensors (accuracy ±1°C) and 1 humidity sensor (monitoring range 30%-60% RH) are arranged on each of the upper, middle and lower layers of the pit. The sensor spacing is ≥1.5m to ensure coverage of the bar stacking area.

5. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S201 grouping and spacing setting: the rolled bars are grouped by specification (diameter difference ≤ 10mm per group), stacked in a "well" shape, and a ventilation gap of ≥ 300mm is left between groups; bars of the same heat number are stacked together, and bars of different heat numbers are separated by insulation boards (thermal conductivity of insulation boards ≤ 0.1W / (m・K)).

6. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The initial temperature record of S202 entering the pit: use a portable thermometer to detect the surface temperature of the rods (measure 3 points per bundle), record the average value as the initial temperature (T0), and when T0>950℃, turn on the circulating fan in the pit (wind speed 0.5m / s) to cool down for 30 minutes and then turn it off.

7. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S203 sealing and insulation start-up: after covering the pit cover, start the edge sealing device (sealing gap ≤ 5mm), and automatically adjust the thickness of the insulation layer according to the initial temperature: when T0 ≥ 900℃, start double-layer insulation (total thickness 150mm), and when T0 < 900℃, start single-layer insulation (thickness 80mm).

8. The method for controlling the temperature-time gradient of the slow cooling pit after rolling of a bar according to claim 1, characterized in that: The S301 real-time temperature monitoring and feedback: collects temperature data from sensors on each layer every 30 minutes, calculates the difference between the average temperature (Tactual) and the theoretical temperature (Ttheoretical) of the corresponding gradient, and triggers regulation when |Tactual - Ttheoretical|>10°C; S302 cooling rate adjustment mechanism: When Tactual>Tactual (cooling too slowly): open the heat dissipation windows on the sides of the pit (the opening area is adjusted in proportion to the over-temperature value, increasing the opening area by 10% for every 10°C over-temperature), and simultaneously start the bottom ventilation (wind speed 0.3-0.8m / s adjustable); When Tactual<Tactual (temperature drops too quickly): close the heat dissipation window and add a temporary insulation layer (add 50mm thickness for every 10℃ drop in temperature), start the pit heating device (power adjustable from 5-15kW) until the temperature difference is ≤5℃, then turn it off; S303 Humidity control assistance: When the humidity in the pit is greater than 60% RH, start the dehumidification device (dehumidification rate ≥ 2kg / h) to maintain the humidity in the range of 40%-50% RH to avoid oxidation and rust on the surface of the rods.

9. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: S401: 4h node verification: When reaching the end of the first-level gradient, detect the core temperature of the bar (using an insertion thermometer, measuring one point per bundle). If the temperature difference between the core and the surface is greater than 80°C, extend the first-level gradient time by 2h and reduce the cooling rate to 30°C / h. S402: 12h node verification: After the second-level gradient is completed, samples are taken to test the hardness of the bars (3 samples are taken for each batch). If the hardness deviation exceeds the standard value by ±5HB, the third-level gradient cooling rate is adjusted (for every 1HB of deviation, the rate is reduced by 1℃ / h); S403: 36h final verification: 1h before the end of slow cooling, the overall temperature of the bar is ≤150℃ and the temperature difference at each point is ≤20℃, which is considered qualified; otherwise, the slow cooling time is extended (2h for every 10℃ increase).

10. The method for controlling the temperature-time gradient of the slow cooling pit after bar rolling according to claim 1, characterized in that: The S501 full-process data storage records: the time of entering the pit, the initial temperature of the bar (surface and core), the average temperature in the pit at each time point (0h, 4h, 12h, 36h), the temperature difference at different locations, the cooling rate adjustment record, the humidity change data, the operating status information of the insulation layer and the ventilation device, and the specifications of the corresponding batch of bars and basic information on the rolling process parameters. All data is stored in an encrypted format and has a retention period of no less than 1 year. It is regularly backed up to an independent storage device to ensure data traceability; S502 Data Review and Pattern Analysis: Slow cooling data is summarized and analyzed weekly to calculate the deviation rate between the actual cooling curve and the theoretical gradient for different specifications and initial temperatures. The frequency and causes of abnormal bar quality (such as excessive hardness and uneven structure) caused by improper temperature control are counted. For high-frequency deviation patterns (such as excessively rapid cooling of a certain specification bar during the 12-36h period), a special analysis model is established to identify influencing factors (such as pit stacking density and insulation layer performance degradation). S503 process parameter optimization: Dynamically adjust the temperature gradient benchmark based on analysis results. For example, for bars with a diameter greater than 80mm, reduce the upper limit of the cooling rate for the secondary gradient (4-12h) from 30°C / h to 25°C / h. When the initial temperature of a batch of bars is consistently above 900°C, increase the initial wind speed of the ventilation device for the primary gradient (0-4h) to 0.6m / s. The optimized parameters must be verified through three small-scale trial rollings and incorporated into the formal process specifications after confirming stable quality. S504 equipment performance calibration: Calibrate the in-pit sensor monthly based on the stored temperature data (debug or replace if the error exceeds ±2°C), check the thermal conductivity of the insulation layer (measured with a heat flow meter, and replace promptly if it exceeds the standard), ensure that the equipment status matches the process parameter requirements, and guarantee the long-term stability of the temperature control accuracy.