A cooling control method for adjusting the flow of a post-rolling cooling spray tank

Abstract

A cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box is disclosed. This method utilizes a circular track combined with a trolley to achieve an infinitely long cooling zone at any workpiece speed. Based on experimentally determined optimal cooling rate, flow rate, water ratio, and production line cooling spray box layout, the corresponding flow rates are converted to production line flow rates according to the principle of consistent flow density, obtaining optimal cooling spray box flow parameters. The flow rates of the production line cooling spray boxes are calibrated, and the opening degree corresponding to the flow rate is calculated based on the calibration curve of each cooling spray box, enabling post-rolling cooling control of the corresponding hot plate. Since the cooling control method described in this invention is implemented under conditions substantially consistent with actual production line operating conditions, product design output and production line process control are more accurate and efficient, effectively accelerating product development speed, improving process control accuracy, and reducing production line trial production costs.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a cooling control method with adjustable flow rate of a cooling spray box after hot plate rolling. Background Technology

[0002] The post-rolling cooling zone of the hot plate consists of several upper and lower cooling spray boxes arranged in a certain length area. Most production lines have a post-rolling cooling zone of about 100 meters in length, with dozens to hundreds of upper and lower spray boxes each, which symmetrically water-cool the upper and lower surfaces of the hot plate.

[0003] Conventional cooling technology after hot plate rolling refers to changing the microstructure of the material by controlling the cooling rate, starting temperature and final cooling temperature after hot plate rolling to meet the performance indicators of the hot plate.

[0004] The multi-path cooling technology after hot plate rolling refers to dividing the cooling zone after hot plate rolling into N cooling zones (N≥2). By controlling the start-up cooling temperature, water cooling rate, stop-cooling temperature, and stop-cooling time between the N cooling zones, multi-path cooling is achieved. By utilizing the phase transformation of the material, the effects of fine grain strengthening and phase transformation strengthening are achieved. Various steel products with excellent microstructure, high strength, and high toughness can be obtained, thus achieving the goal of reducing costs by replacing metal with water.

[0005] The technology of uniform cooling in thickness after hot plate rolling refers to the use of water ratio in the upper and lower cooling spray boxes to achieve uniform cooling in thickness, thereby optimizing the shape of the hot plate after cooling.

[0006] The cooling rate is directly related to the spray box flow rate, and the water ratio is also related to the spray box flow rate. Under normal circumstances, controlling the cooling rate and water ratio requires adjusting the spray box flow rate. However, due to the harsh working conditions during water spray cooling, it is difficult to detect the actual temperature of the steel plate, making it very difficult to evaluate the cooling rate and cooling uniformity. Generally, evaluation can only be carried out by trial rolling and sampling performance testing at different spray box flow rates. However, this results in a long cycle, a significant reduction in scrap, and high trial rolling costs, which greatly limits the production capacity of high-strength steel with microstructure control in production lines.

[0007] The process can also be explored and verified through post-rolling cooling of a hot rolling test mill. However, the current hot rolling test mills differ greatly from the actual field conditions, especially in terms of the hot plate threading speed. To achieve the same speed as in the field, the cooling zone would need to be designed to be nearly 100 meters long, which is obviously impractical. In fact, there is currently no such test mill. Therefore, the performance of the hot plate obtained from the test mill often differs significantly from that in actual field production. Furthermore, it is even more difficult to convert the process parameters obtained from the thermal simulator into actual production process parameters. Due to the differences in experimental conditions, some process parameters obtained from the hot rolling test mill and the thermal simulator are even impossible to achieve on the production line.

[0008] In summary, there is currently no method or device, either domestically or internationally, to achieve an infinitely long cooling zone at any workpiece speed, and no cooling control method with adjustable flow rate for the hot plate post-rolling cooling spray box. Summary of the Invention

[0009] The purpose of this invention is to provide a cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box. By combining a circular track with a trolley, an infinitely long cooling zone is achieved at any workpiece speed. Based on the experimentally determined optimal cooling rate, flow rate, water ratio, and production line cooling spray box layout, the corresponding flow rate is converted into the production line flow rate according to the principle of consistent flow density, obtaining the optimal spray box flow rate parameters. The flow rate of the production line cooling spray boxes is calibrated, and the opening degree corresponding to the flow rate is calculated based on the calibration curve of each cooling spray box, enabling post-rolling cooling control of the corresponding hot plate. Because the cooling control method described in this invention is implemented under conditions that are basically consistent with the actual operating conditions of the production line, product design output and production line process control are more accurate and efficient, effectively accelerating product development speed, improving process control accuracy, and reducing production line trial production costs.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] A cooling control method with adjustable flow rate for a hot-rolled plate cooling spray box includes the following steps:

[0012] 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a sample support platform. The circular track is an elliptical track consisting of two parallel straight sections and two semicircular sections. At least one cooling spray box is set along the straight sections of the track to cool the upper and / or lower surfaces of the sample. Each cooling spray box includes upper and lower spray boxes. The sample is heated to a set temperature by a heating device that spans the circular track or is mounted on the trolley. During this process, the temperature of the sample is measured by a temperature measuring device mounted on the trolley.

[0013] 2) The trolley is started, and it carries the heated sample in a circular motion at a constant speed or with a certain acceleration, according to a specified process speed. The sample passes through the cooling spray box, where jets from the cooling spray box spray onto the sample, simultaneously cooling both the upper and lower surfaces. During this process, the sample is driven at a set speed through a theoretically infinitely long cooling zone, ensuring that the sample is cooled from the initial cooling temperature to the set target temperature under conditions consistent with the production line operating conditions. The sample temperature and cooling rate are monitored and obtained in real time.

[0014] Sample running speed: 0–25 m / s, acceleration: 0–0.5 m / s² 2 ;

[0015] The flow rate adjustment range for each cooling spray box is 0–300 m³ / h. 3 / h, preferably 10-50m3 Cooling experiments were conducted by setting the flow rate intervals to increase or decrease at intervals of / h;

[0016] The cooling temperature is 700-1000℃. Preferably, the cooling experiment is conducted by setting the temperature increments or decreases of 40-60℃.

[0017] The cooling temperature ranges from room temperature to 800℃. Preferably, the experiment is conducted by setting the temperature increments or decreases of 30℃ to 50℃.

[0018] If there are more than two cooling spray boxes, the spacing between the cooling spray boxes should be consistent with the production line design.

[0019] 3) Perform performance and microstructure tests on the samples;

[0020] 4) Repeat steps 2) to 3) and select cooling control parameters that meet the requirements in terms of performance and organization based on the measured data;

[0021] 5) Convert the flow rate obtained from the experiment corresponding to the optimal cooling rate into the production line flow rate according to the principle of consistent flow density, with a flow range of 0–300 m³ / s. 3 / h;

[0022] 6) Calibrate the flow rate of the cooling spray boxes on the production line, measure the correspondence between the flow rate of each cooling spray box and the opening degree of the flow regulating valve, and form a calibration curve; the opening degree range is 0% to 100%, and the opening degree interval is 5% to 20%;

[0023] 7) Convert the flow rate to the production line, calculate the corresponding opening degree based on the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m³. 3 / h, opening range 0% to 100%.

[0024] Preferably, in step 2), the cooling rate CR of the steel plate is calculated based on the starting cooling temperature T1, the stopping cooling temperature T2, and the cumulative cooling time t recorded during the experiment. The cumulative cooling time t is in seconds, and the cooling rate ranges from 0 to 1000℃ / s.

[0025] Preferably, in step 3), the performance Xact of the steel plate is measured by a testing device. Xact is considered qualified if it is within the allowable positive and negative tolerance range of the target performance Xtar, i.e., ΔX1≤(Xact-Xtar)≤ΔX2, where ΔX1: negative tolerance, ΔX2: positive tolerance. The target performance and the range of positive and negative tolerances of the steel plate are determined by the user's requirements.

[0026] Preferably, in step 4), the experimental results under different combinations of cooling rate, start-up cooling temperature and stop-down cooling temperature are statistically analyzed, and the combination that meets the product performance is selected for comprehensive comparison. Based on the production line layout and process system, the optimal cooling rate, start-up cooling temperature and stop-down cooling temperature that meet the maximum process window of product production are determined; the preferred start-up cooling temperature is 800~950℃, and the preferred stop-down cooling temperature is 550℃~750℃.

[0027] The present invention also provides a cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling, which includes the following steps:

[0028] 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a support platform. The circular track is an elliptical track consisting of two parallel straight sections and semi-circular arc sections at both ends. At least one cooling spray box is set along the straight sections of the track to cool the upper and / or lower surfaces of the sample. The support platform for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample are unobstructed. The jets from the cooling spray box are directly sprayed onto the sample, forming two straight cooling zones. The sample is heated to a set temperature by a heating device set across the circular track or on the trolley. During this process, the temperature of the sample is measured by a temperature measuring device set on the trolley.

[0029] 2) Drive the trolley to move the sample to the specified process speed, maintain a constant speed or accelerate at a certain speed, and pass through the theoretically infinitely long cooling zone in motion to ensure that the sample is cooled from the starting cooling temperature to the target temperature under conditions that are basically consistent with the field conditions. The temperature is detected in real time during the cooling process, the cooling time is accumulated in real time, and the cooling stop time is precisely controlled.

[0030] 3) Conduct combined cooling experiments on samples of a certain steel grade and thickness under different flow rates, stopping temperatures, and stopping times in N cooling zones to determine the cooling rate and steel plate properties; the flow rate range is 0–300 m³ / s. 3 / h, preferably at equal flow intervals of 10–50m 3 The experiment was conducted at a temperature range of 500–1000℃, preferably at equal temperature intervals of 40–60℃. The cooling temperature range was 100–800℃, preferably at equal temperature intervals of 30–50℃. The cooling time was 0–20 seconds, preferably at equal time intervals of 2–4 seconds. During this period, the sample running speed ranged from 0–25 m / s, and the acceleration ranged from 0–0.5 m / s². 2 ;

[0031] 4) Calculate the cooling rates of N cooling zones based on the experimental data, and determine the properties of the steel plate using a testing device; among which,

[0032] Based on the recorded cooling temperatures T of the N cooling zones during the experiment... n1 Stop cooling temperature T n2, Cumulative cooling time t n , the cooling rate CR of the steel plates in N cooling zones can be calculated n = (starting cooling temperature T n1 - starting cooling temperature T n2 ) / cumulative cooling time t n , n = 1 to N; starting cooling temperature range is 500 - 1000 °C, stopping cooling temperature is 100 - 800 °C, cooling rate range is 0 - 1000 °C / s;

[0033] By measuring the performance Xact of the steel plate with a detection device, if Xact is within the positive and negative tolerance ranges allowed by the target performance Xtar, it is considered qualified, that is, ΔX1 ≤ (Xact - Xtar) ≤ ΔX2; ΔX1:

[0034] negative tolerance, ΔX2: positive tolerance, the steel plate target performance and positive and negative tolerance ranges are determined by user requirements;

[0035] 5) Determination of the optimal cooling process parameters

[0036] Select the combinations of cooling rate, starting cooling temperature, stopping cooling temperature, and stopping cooling time in N cooling zones with qualified performance, and determine the optimal cooling rate, starting cooling temperature, stopping cooling temperature, and stopping cooling time in N cooling zones that meet the maximum process window for product production according to the production line layout and process system;

[0037] Preferably, the starting cooling temperature in the first cooling zone is 800 - 950 °C, and the stopping cooling time between cooling zones is 4 - 12 s;<0000​​​​​​​​​​​​​​Preferably, in step 1), the distance between the spray box and the sample surface and the nozzle diameter are arbitrarily adjustable. The basic principle is that the flow rate of cooling water to the sample surface is consistent with the production line design, thereby ensuring that the experimental cooling rate is consistent with the production line under the premise that the cooling process is consistent with the production line. The nozzle diameter of the cooling spray box is in the range of 3 to 30 mm, and the distance between the cooling spray box and the sample surface is in the range of 50 to 2200 mm.

[0042] Preferably, in step 1), the spacing, flow rate, and number of nozzles of the cooling spray boxes are arbitrarily adjustable to ensure that the experimental cooling rate is consistent with the production line under the premise that the cooling process is consistent with the production line. The spacing of the cooling spray boxes ranges from 0 to 1.5 m, and the flow rate of the cooling spray boxes ranges from 0 to 300 m³ / h. 3 / h, the number of nozzles in the cooling spray box ranges from 1 to 200; the length of the cooling spray box ranges from 100 to 6000 mm.

[0043] Preferably, the vehicle is driven by an electric motor or by traction.

[0044] Preferably, the circular motion speed of the sample, i.e., linear velocity or angular velocity, is monitored in real time, and the velocity of the sample can be changed online according to the measured temperature data based on the predetermined cooling process, i.e., increasing speed, decreasing speed, or maintaining a constant speed.

[0045] Preferably, the sample is heated offline or online. Preferably, the offline heating method involves heating the sample to the required process temperature, then fixing it on the sample support platform. When the sample approaches the predetermined cooling temperature, the trolley is driven to move along the circular track, carrying the sample through the cooling spray box, i.e., through a theoretically infinitely long cooling zone, to complete the cooling or heat treatment process. The online heating method involves fixing the sample on the sample support platform first, then heating it. When the required process temperature is reached, the heating device is removed from the circular track area, and then the trolley is driven to move along the circular track to complete the cooling or heat treatment process.

[0046] Preferably, the heating is performed by resistance heating, that is, the sample is held on both sides by electrodes and heated directly online by a large current; or, induction heating is performed.

[0047] Preferably, water cooling or air cooling is used to cool the sample.

[0048] The beneficial effects of this invention are:

[0049] This invention employs a circular track combined with a trolley to achieve an infinitely long cooling zone at any workpiece speed. Based on the optimal cooling rate, flow rate, water ratio, and production line cooling spray box layout determined experimentally, the corresponding flow rate is converted into the production line flow rate according to the principle of consistent flow density, thus obtaining the optimal spray box flow rate parameters. The flow rate of the production line cooling spray boxes is calibrated, and the opening degree corresponding to the flow rate is calculated based on the calibration curve of each cooling spray box, thereby controlling the post-rolling cooling of the corresponding hot plate.

[0050] Since the cooling control method described in this invention is implemented under conditions that are essentially consistent with the actual operating conditions of the production line, it makes product design output and production line process control more accurate and efficient, effectively accelerating product development, improving process control precision, and reducing production line trial production costs. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the cooling experimental apparatus for the cooling control method described in this invention. Detailed Implementation

[0052] See Figure 1 The present invention discloses a cooling control method with adjustable flow rate of a cooling spray box after hot plate rolling, which includes the following steps:

[0053] 1) A circular track 1 combined with a trolley 2 is used. The trolley 2 carries the sample 100 in a circular motion via a sample support platform 3. The circular track 1 is an elliptical track consisting of two parallel straight sections and two semicircular sections. At least one cooling spray box 4 is set along the straight sections to cool the upper and / or lower surfaces of the sample, forming two straight cooling zones. Each cooling spray box 4 includes upper and lower cooling spray boxes. The support platform 3 for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample 100 are unobstructed. The jets emitted from the cooling spray boxes 4 are directly sprayed onto the sample 100. The sample is heated to a set temperature by a heating device 5 that spans the circular track 1 or is set on the trolley 2. During this process, a temperature measuring device 61 set on the trolley 2 measures the temperature of the sample 100. The temperature measuring device 61 transmits the data to the temperature measuring host 62 wirelessly or via wired means. The temperature measuring host 62 is connected to a controller PLC.

[0054] 2) The trolley is started, and it carries the heated sample in a circular motion at a constant speed or with a certain acceleration, according to a specified process speed. The sample passes through the cooling spray box, where jets from the cooling spray box spray onto the sample, simultaneously cooling both the upper and lower surfaces. During this process, the sample is driven at a set speed through a theoretically infinitely long cooling zone, ensuring that the sample is cooled from the initial cooling temperature to the set target temperature under conditions consistent with the production line operating conditions. The sample temperature and cooling rate are monitored and obtained in real time.

[0055] Sample running speed: 0–25 m / s, acceleration: 0–0.5 m / s²2 ;

[0056] The flow rate adjustment range for each cooling spray box is 0–300 m³ / h. 3 / h, preferably 10-50m 3 Cooling experiments were conducted by setting the flow rate intervals to increase or decrease at intervals of / h;

[0057] The cooling temperature is 700-1000℃. Preferably, the cooling experiment is conducted by setting the temperature increments or decreases of 40-60℃.

[0058] The cooling temperature ranges from room temperature to 800℃. Preferably, the experiment is conducted by setting the temperature increments or decreases of 30℃ to 50℃.

[0059] If there are more than two cooling spray boxes, the spacing between the cooling spray boxes should be consistent with the production line design; the cooling spray boxes include upper and lower cooling spray boxes.

[0060] 3) Perform performance and microstructure tests on the samples;

[0061] 4) Repeat steps 2) to 3) and select cooling control parameters that meet the requirements in terms of performance and organization based on the measured data;

[0062] 5) Convert the flow rate obtained from the experiment corresponding to the optimal cooling rate into the production line flow rate according to the principle of consistent flow density, with a flow range of 0–300 m³ / s. 3 / h;

[0063] 6) Calibrate the flow rate of the cooling spray boxes on the production line, measure the correspondence between the flow rate of each cooling spray box and the opening degree of the flow regulating valve, and form a calibration curve; the opening degree range is 0% to 100%, and the opening degree interval is 5% to 20%;

[0064] 7) Convert the flow rate to the production line, calculate the corresponding opening degree based on the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m³. 3 / h, opening range 0% to 100%.

[0065] Preferably, in step 2), the cooling rate CR of the steel plate is calculated based on the starting cooling temperature T1, the stopping cooling temperature T2, and the cumulative cooling time t recorded during the experiment. The cumulative cooling time t is in seconds, and the cooling rate ranges from 0 to 1000℃ / s.

[0066] Preferably, in step 3), the performance Xact of the steel plate is measured by a testing device. Xact is considered qualified if it is within the allowable positive and negative tolerance range of the target performance Xtar, i.e., ΔX1≤(Xact-Xtar)≤ΔX2, where ΔX1: negative tolerance, ΔX2: positive tolerance. The target performance and the range of positive and negative tolerances of the steel plate are determined by the user's requirements.

[0067] Preferably, in step 4), the experimental results under different combinations of cooling rate, start-up cooling temperature and stop-down cooling temperature are statistically analyzed, and the combination that meets the product performance is selected for comprehensive comparison. Based on the production line layout and process system, the optimal cooling rate, start-up cooling temperature and stop-down cooling temperature that meet the maximum process window of product production are determined; the preferred start-up cooling temperature is 800~950℃, and the preferred stop-down cooling temperature is 550℃~750℃.

[0068] The present invention also provides a cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling, which includes the following steps:

[0069] 1) A circular track 1 combined with a trolley 2 is used. The trolley 2 carries the sample 100 in a circular motion via a sample support platform 3. The circular track 1 is an elliptical track consisting of two parallel straight sections and two semicircular sections. At least one cooling spray box 4 is set along the straight sections to cool the upper and / or lower surfaces of the sample, forming two straight cooling zones. Each cooling spray box 4 includes upper and lower cooling spray boxes. The support platform 3 for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample 100 are unobstructed. The jets emitted from the cooling spray boxes 4 are directly sprayed onto the sample 100. The sample is heated to a set temperature by a heating device 5 that spans the circular track 1 or is set on the trolley 2. During this process, a temperature measuring device 61 set on the trolley 2 measures the temperature of the sample 100. The temperature measuring device 61 transmits the data to the temperature measuring host 62 wirelessly or via wired means. The temperature measuring host 62 is connected to a controller PLC.

[0070] 2) Drive the trolley to move the sample to the specified process speed, maintain a constant speed or accelerate at a certain speed, and pass through the theoretically infinitely long cooling zone in motion to ensure that the sample is cooled from the starting cooling temperature to the target temperature under conditions that are basically consistent with the field conditions. The temperature is detected in real time during the cooling process, the cooling time is accumulated in real time, and the cooling stop time is precisely controlled.

[0071] 3) Conduct combined cooling experiments on samples of a certain steel grade and thickness under different flow rates, stopping temperatures, and stopping times in N cooling zones to determine the cooling rate and steel plate properties; the flow rate range is 0–300 m³ / s. 3 / h, preferably at equal flow intervals of 10–50m 3Perform experiments at a cooling start temperature range of 500 - 1000 °C, preferably at equal temperature intervals of 40 - 60 °C, a cooling stop temperature range of 100 - 800 °C, preferably at equal temperature intervals of 30 - 50 °C, and a cooling stop time of 0 - 20 s, preferably at equal time intervals of 2 - 4 s; during this period, the sample running speed range is 0 - 25 m / s, and the acceleration range is 0 - 0.5 m / s 2 ;

[0072] 4) Calculate the cooling rate of N cooling zones based on the data recorded in the experiments, and measure the properties of the steel plate through a detection device; where

[0073] Based on the cooling start temperature T n1 and cooling stop temperature T n2 and cumulative cooling time t n recorded in the N cooling zones during the experiment process, the cooling rate CR n of the steel plate in the N cooling zones can be calculated as CR n1 = (cooling start temperature T n2 - cooling start temperature T n ) / cumulative cooling time t, where n = 1 - N; the cooling start temperature range is 500 - 1000 °C, the cooling stop temperature is 100 - 800 °C, and the cooling rate range is 0 - 1000 °C / s; <no value> Measure the properties Xact of the steel plate through a detection device, and if Xact is within the positive and negative tolerances allowed by the target property Xtar, it is considered qualified, that is, ΔX1 ≤ (Xact - Xtar) ≤ ΔX2; ΔX1: <no value> negative tolerance, ΔX2: positive tolerance, the steel plate target property and the positive and negative tolerance ranges are determined by user requirements; <no value>5) Determination of the optimal cooling process parameters<00002,47><no value> Select the combinations of cooling rate, cooling start temperature, cooling stop temperature, and cooling stop time of the N cooling zones with qualified properties, and determine the optimal cooling rate, cooling start temperature, cooling stop temperature, and cooling stop time of the N cooling zones that meet the maximum process window for product production according to the production line layout and process regime; preferably, the cooling start temperature of the first cooling zone is 800 - 950 °C, and the cooling stop time between cooling zones is 4 - 12 s; <no value>6) For the corresponding relationship between the cooling rate and flow rate of the N cooling zones determined by the multi-path cooling of a sample of a certain steel grade and thickness specification, convert the flow rate corresponding to the optimal cooling rate of the N cooling zones obtained from the experiment into the production line flow rate according to the principle of consistent flow rate density, and the flow rate range is 0 - 300 m 3 / h; <no value>7) Calibrate the flow rate of the cooling spray boxes on the production line, measure the correspondence between the flow rate of each cooling spray box and the opening degree of the flow regulating valve, and form a calibration curve; the opening degree range is 0% to 100%, and the opening degree interval is 5% to 20%;

[0080] 8) Convert the flow rate into the flow rate of N cooling zones on the production line. Based on the calibration curve of each cooling spray box, calculate the opening degree of the N cooling zones corresponding to the flow rate and set the control accordingly; the flow rate range is 0~300m³. 3 / h, flow regulating valve opening range 0% to 100%.

[0081] Preferably, in step 1), the distance between the spray box and the sample surface and the nozzle diameter are arbitrarily adjustable. The basic principle is that the flow rate of cooling water to the sample surface is consistent with the production line design, thereby ensuring that the experimental cooling rate is consistent with the production line under the premise that the cooling process is consistent with the production line. The nozzle diameter of the cooling spray box is in the range of 3 to 30 mm, and the distance between the cooling spray box and the sample surface is in the range of 50 to 2200 mm.

[0082] Preferably, in step 1), the spacing, flow rate, and number of nozzles of the cooling spray boxes are arbitrarily adjustable to ensure that the experimental cooling rate is consistent with the production line under the premise that the cooling process is consistent with the production line. The spacing of the cooling spray boxes ranges from 0 to 1.5 m, and the flow rate of the cooling spray boxes ranges from 0 to 300 m³ / h. 3 / h, the number of nozzles in the cooling spray box ranges from 1 to 200; the length of the cooling spray box ranges from 100 to 6000 mm.

[0083] Preferably, the vehicle is driven by an electric motor or by traction.

[0084] Preferably, the circular motion speed of the sample, i.e., linear velocity or angular velocity, is monitored in real time, and the velocity of the sample can be changed online according to the measured temperature data based on the predetermined cooling process, i.e., increasing speed, decreasing speed, or maintaining a constant speed.

[0085] Preferably, the sample is heated offline or online. Preferably, the offline heating method involves heating the sample to the required process temperature, then fixing it on the sample support platform. When the sample approaches the predetermined cooling temperature, the trolley is driven to move along the circular track, carrying the sample through the cooling spray box, i.e., through a theoretically infinitely long cooling zone, to complete the cooling or heat treatment process. The online heating method involves fixing the sample on the sample support platform first, then heating it. When the required process temperature is reached, the heating device is removed from the circular track area, and then the trolley is driven to move along the circular track to complete the cooling or heat treatment process.

[0086] Preferably, the heating is performed by resistance heating, that is, the sample is held on both sides by electrodes and heated directly online by a large current; or, induction heating is performed.

[0087] Preferably, water cooling or air cooling is used to cool the sample.

[0088] Example 1

[0089] The conventional cooling control method for adjustable flow rate of the cooling spray box after hot plate rolling involves converting the flow rate corresponding to the optimal cooling rate obtained experimentally into the production line flow rate according to the principle of consistent flow density, based on the experimentally determined relationship between cooling rate and flow rate. This flow rate is then converted into the regulating valve opening for cooling control. Specifically, this includes:

[0090] 1) Layout of the cooling spray box of the experimental setup and experimental results

[0091] The spacing between the spray boxes in the experimental setup is the same as the layout of the cooling spray boxes after rolling on a certain production line. The spacing is 0.36m, with 6 sets of spray boxes arranged on one side and a cooling zone length of 2.16m. There are a total of 12 sets of spray boxes on both sides.

[0092] The production line spray box is 2m long, and the flow rate of a single upper spray box is 108m³. 3 / h, the flow rate of a single lower spray box is 108m³ / h 3 / h;

[0093] The length of the spray box in the experimental setup is 0.5m;

[0094] The flow rate of a single top spray box in the experimental setup is 10⁸ m³. 3 / h*0.5 / 2=27m 3 / h;

[0095] The flow rate of a single lower spray box in the experimental setup is 10⁸ m³ / s. 3 / h*0.5 / 2=27m 3 / h;

[0096] Based on the experimentally determined conventional cooling process parameters for a certain steel grade with a thickness of 4.5mm: initial cooling temperature 850℃, final cooling temperature 600℃, and cooling rate 32℃ / s, these were used as the production line process parameters. The flow rate of the single spray box in the cooling experimental device was 18m³ / s. 3 / h.

[0097] 2) Convert the flow rate obtained from the experiment corresponding to the optimal cooling rate into the production line flow rate.

[0098] The production line spray box is 2m long, and the flow rate of a single upper spray box is 108m³. 3 / h, the flow rate of a single lower spray box is 108m³ / h 3 / h;

[0099] The length of the spray box in the experimental setup is 0.5m;

[0100] The spacing between the cooling spray boxes in a certain production line is the same as the spacing between the spray boxes in the experimental device. Based on the principle of consistent flow density, the conversion can be made according to the length of the spray boxes.

[0101] The flow rate of a single strip in the post-rolling cooling spray box on the production line is 18m³. 3 / h*2 / 0.5=72m 3 / h;

[0102] The flow rate of a single strip in the post-rolling cooling spray box on the production line is 18m³. 3 / h*2 / 0.5=72m 3 / h;

[0103] 3) Convert the flow rate of the production line spray box into the opening degree of the regulating valve for cooling control.

[0104] After calibrating the flow control valve on the production line, the flow rate was found to be 80 m³ / s at 70% opening. 3 / h, the flow rate is 65m³ at 60% opening. 3 / h, for 72m 3 The opening value of / h flow rate is then subjected to conventional linear interpolation:

[0105] Opening value = (72-65)*(70%-60%) / (80-65)+60% = 66.6%,

[0106] Set and control the flow valves and cooling of the production line according to this opening value.

[0107] Example 2

[0108] A multi-path cooling control method with adjustable flow rate in the hot plate post-rolling cooling spray box is proposed. Based on the experimentally determined correspondence between cooling rate and flow rate, the flow rate corresponding to the optimal cooling rate in different multi-path cooling zones is converted into the production line flow rate according to the principle of consistent flow density. Then, the flow rate is converted into the valve opening degree of different multi-path cooling zones for cooling control. Specifically, this includes:

[0109] 1) Layout of the cooling spray box of the experimental setup and experimental results

[0110] The spacing between the spray boxes in the experimental setup is the same as the layout of the cooling spray boxes after rolling on a certain production line. The spacing is 0.36m, with 6 sets of spray boxes arranged on one side and a cooling zone length of 2.16m. There are a total of 12 sets of cooling spray boxes on both sides.

[0111] The production line cooling spray box is 2m long, and the flow rate of a single upper spray box is 200m³. 3 / h, the flow rate of a single lower spray box is 240m³ / h. 3 / h;

[0112] The length of the cooling spray box in the experimental setup is 0.5m;

[0113] The flow rate of a single spray box in the experimental setup is 200 m³. 3 / h*0.5 / 2=50m 3 / h;

[0114] The flow rate of a single lower spray box in the experimental setup is 240 m³ / h. 3 / h*0.5 / 2=60m 3 / h;

[0115] Based on the experimentally determined conventional cooling process parameters for a certain steel grade with a thickness of 4.5mm:

[0116] Cooling temperature 870℃, pre-phase change spray flow rate 250m³ 3 / h, pre-phase change downspray flow rate 300m³ 3 / h, phase change temperature 680℃, cooling rate after phase change 75℃ / s, phase change time 5, upward spray flow rate after phase change 150m 3 / h, downstream spray flow rate after phase change 180m 3 The production line process parameters are: final cooling temperature of 560℃ and cooling rate after phase change of 75℃ / s. The flow rate of the single spray box in the cooling test device is: 42m³ / h before phase change. 3 / h, downward spray flow rate before phase change 50m 3 / h, upward spray flow rate after phase change: 25m³ / h 3 / h, downstream spray flow rate after phase change 30m 3 / h.

[0117] 2) Convert the flow rate obtained from the experiment corresponding to the optimal cooling rate into the production line flow rate.

[0118] The production line cooling spray box is 2m long, and the flow rate of a single upper spray box is 200m³. 3 / h, the flow rate of a single lower spray box is 240m³ / h. 3 / h;

[0119] The length of the cooling spray box in the experimental setup is 0.5m;

[0120] The spacing between the cooling spray boxes in a certain production line after rolling is the same as the spacing between the spray boxes in the experimental setup. Based on the principle of consistent flow density, the calculation can be performed using the length of the spray boxes.

[0121] The flow rate of a single upper spray box in the post-rolling cooling spray box of the pre-phase change production line is 42m³. 3 / h*2 / 0.5=168m 3 / h;

[0122] The flow rate of a single lower spray box in the post-rolling cooling spray box of the pre-phase change production line is 50m³. 3 / h*2 / 0.5=200m 3 / h;

[0123] The flow rate of a single strip in the post-rolling cooling spray box of the production line after phase change is 25m³. 3 / h*2 / 0.5=100m 3 / h;

[0124] The flow rate of a single lower spray box in the post-rolling cooling spray box of the production line after phase change is 30m³. 3 / h*2 / 0.5=120m 3 / h;

[0125] 3) Convert the flow rate of the production line spray box into the opening degree of the regulating valve for cooling control.

[0126] After calibrating the production line flow control valve, the following results were obtained:

[0127] The flow rate is 180 m³ / h when the upper spray box is 85% open. 3 / h, with a flow rate of 165m³ / h at 80% opening. 3 / h, for 168m 3 Linear interpolation of the opening value of / h flow rate:

[0128] Opening value = (168-165)*(85%-80%) / (180-165)+80%=81%;

[0129] The flow rate is 110 m³ / h when the upper spray box is 50% open. 3 / h, with a flow rate of 95m³ at 45% opening. 3 / h, for 100m 3 Linear interpolation of the opening value of / h flow rate:

[0130] Opening value = (100-95)*(50%-45%) / (110-95)+45% = 46.7%;

[0131] The flow rate is 215m³ when the lower spray box is 85% open. 3 / h, with a flow rate of 190m³ / h at 80% opening. 3 / h, for 200m 3 Linear interpolation of the opening value of / h flow rate:

[0132] Opening value = (200-190)*(85%-80%) / (215-190)+80%=82%;

[0133] The flow rate is 135m³ when the lower spray box is 50% open. 3 / h, the flow rate is 115m³ at 45% opening. 3 / h, for 120m 3 Linear interpolation of the opening value of / h flow rate:

[0134] Opening value = (120-115)*(50%-45%) / (135-115)+45%=46.3%;

[0135] Set and control the flow valves and cooling of the production line according to this opening value.

Claims

1. A cooling control method with adjustable flow rate for a cooling spray box after hot plate rolling, characterized in that, Includes the following steps: 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a sample support platform. The circular track is an elliptical track consisting of two parallel straight sections and two semicircular sections. At least one cooling spray box is set along the straight sections of the track to cool the upper and / or lower surfaces of the sample. Each cooling spray box includes upper and lower cooling spray boxes. The sample is heated to a set temperature by a heating device that spans the circular track or is mounted on the trolley. During this process, the temperature of the sample is measured by a temperature measuring device mounted on the trolley. 2) The trolley is started, and it carries the heated sample in a circular motion at a constant speed or with a certain acceleration, according to a specified process speed. The sample passes through the cooling spray box, where jets of water are sprayed onto the sample, simultaneously cooling both the upper and lower surfaces. During this process, the sample is driven through a theoretically infinitely long cooling zone at a set speed, ensuring that the sample is cooled from the initial cooling temperature to the set target temperature under conditions consistent with the production line operating conditions. The sample temperature and cooling rate are monitored and obtained in real time. Sample running speed: 0~25m / s, acceleration: 0~0.5m / s² 2 ; The flow rate adjustment range for each cooling spray box is 0~300m³. 3 / h; The cooling temperature is 700~1000℃; The cooling stop temperature is room temperature to 800℃; If there are more than two cooling spray boxes, the spacing between the cooling spray boxes should be consistent with the production line design. 3) Perform performance and microstructure tests on the samples; 4) Repeat steps 2) to 3), and select cooling control parameters that meet the requirements for performance and organization based on the measured data; 5) Convert the flow rate obtained from the experiment corresponding to the optimal cooling rate into the production line flow rate according to the principle of consistent flow density, with a flow range of 0~300m³. 3 / h; 6) Calibrate the flow rate of the cooling spray boxes on the production line, and determine the correspondence between the flow rate of each cooling spray box and the opening degree of the flow regulating valve to form a calibration curve; the opening degree range is 0%~100%, and the opening degree interval is 5%~20%; 7) Convert the flow rate to the production line, calculate the corresponding opening degree based on the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m³. 3 / h, opening range 0%~100%.

2. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1, characterized in that, Step 2) Based on the starting cooling temperature T1, stopping cooling temperature T2 and cumulative cooling time t recorded during the experiment, calculate the cooling rate CR of the steel plate = (starting cooling temperature T1 - stopping cooling temperature T2) / cumulative cooling time t, where the cumulative cooling time t is in seconds; the cooling rate range is 0~1000℃ / s.

3. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1, characterized in that, Step 3) Measure the performance Xact of the steel plate using a testing device. If Xact is within the allowable positive and negative tolerance range of the target performance Xtar, it is considered qualified, that is, ΔX1≤(Xact-Xtar)≤ΔX2, where ΔX1: negative tolerance, ΔX2: positive tolerance. The target performance and positive and negative tolerance range of the steel plate are determined by the user's requirements.

4. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1, characterized in that, In step 4), the experimental results under different combinations of cooling rate, start-up cooling temperature and stop-down cooling temperature are statistically analyzed. The combination that meets the product performance is selected for comprehensive comparison. Based on the production line layout and process system, the optimal cooling rate, start-up cooling temperature and stop-down cooling temperature that meet the maximum process window of product production are determined.

5. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 4, characterized in that, In step 4), the starting temperature for cooling is 800~950℃, and the stopping temperature is 550℃~750℃.

6. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as described in claim 1, characterized in that, In step 2), the flow rate adjustment range for each cooling spray box is 0~300m³. 3 / h, according to 10~50m 3 Cooling experiments were conducted by setting the flow rate intervals to increase or decrease at intervals of / h.

7. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as described in claim 1, characterized in that, In step 2), the cooling temperature is set to 700~1000℃, and the cooling experiment is conducted by increasing or decreasing the temperature in increments of 40~60℃.

8. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as described in claim 1, characterized in that, In step 2), the cooling temperature is set from room temperature to 800℃, and the experiment is conducted by increasing or decreasing the temperature in increments of 30℃ to 50℃.

9. A cooling control method with adjustable flow rate for a cooling spray box after hot plate rolling, characterized in that, Includes the following steps: 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a support platform. The circular track is an elliptical track consisting of two parallel straight sections and semi-circular arc sections at both ends. At least one cooling spray box is set along the straight sections of the track to cool the upper and / or lower surfaces of the sample. The support platform for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample are unobstructed. The jets from the cooling spray box are directly sprayed onto the sample, forming two straight cooling zones. The sample is heated to a set temperature by a heating device set across the circular track or on the trolley. During this process, the temperature of the sample is measured by a temperature measuring device set on the trolley. 2) The trolley is driven to move the sample to reach the specified process speed, maintain a constant speed or accelerate at a certain speed, and pass through the theoretically infinitely long cooling zone in motion to ensure that the sample is cooled from the starting cooling temperature to the target temperature under conditions that are basically consistent with the field conditions. The temperature is monitored in real time during the cooling process, the cooling time is accumulated in real time, and the cooling stop time is precisely controlled. 3) Conduct combined cooling experiments on samples of a certain steel grade and thickness under different flow rates, stopping temperatures, and stopping times in N cooling zones to determine the cooling rate and steel plate properties; the flow rate range is 0~300 m³ / h. 3 / h, cooling start temperature range 500~1000℃, cooling stop temperature range 100~800℃, cooling stop time 0~20s; during this period, sample running speed range: 0~25m / s, acceleration range 0~0.5m / s². 2 ; 4) Calculate the cooling rates of N cooling zones based on the experimental data, and determine the properties of the steel plate using a testing device; among which, Based on the recorded cooling temperatures T of the N cooling zones during the experiment... n1 Stop cooling temperature T n2 Cumulative cooldown time t n The cooling rate CR of the steel plate in N cooling zones can be calculated. n = (cooling temperature T) n1 - Cooling temperature T n2 ) / Cumulative Cooldown Time t n n=1~N; Cooling start temperature range 500~1000℃, cooling stop temperature 100~800℃, cooling rate range 0~1000℃ / s; The performance Xact of the steel plate is measured by a testing device. If Xact is within the allowable positive and negative tolerance range of the target performance Xtar, it is considered qualified, that is, ΔX1≤(Xact-Xtar)≤ΔX2; ΔX1: negative tolerance, ΔX2: positive tolerance. The target performance and the range of positive and negative tolerances of the steel plate are determined by the user's requirements. 5) Determination of optimal cooling process parameters Select the combination of cooling rate, start-up temperature, stop-up temperature and stop-up time of N qualified cooling zones, and determine the optimal cooling rate, start-up temperature, stop-up temperature and stop-up time of N cooling zones to meet the maximum process window of product production based on the production line layout and process system. 6) For a sample of a certain steel grade and thickness, determine the correspondence between the cooling rate and flow rate of N cooling zones determined by multi-path cooling. Convert the flow rate corresponding to the optimal cooling rate of the N cooling zones obtained in the experiment into the production line flow rate according to the principle of consistent flow density. The flow rate range is 0~300m³. 3 / h; 7) Calibrate the flow rate of the cooling spray boxes on the production line, and determine the correspondence between the flow rate of each cooling spray box and the opening degree of the flow regulating valve to form a calibration curve; the opening degree range is 0%~100%, and the opening degree interval is 5%~20%; 8) Convert the flow rate into the flow rate of N cooling zones on the production line. Based on the calibration curve of each cooling spray box, calculate the opening degree of the N cooling zones corresponding to the flow rate and set the control accordingly; the flow rate range is 0~300m³. 3 / h, the flow regulating valve opening range is 0%~100%.

10. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, In step 1), the distance between the spray box and the sample surface and the nozzle diameter are arbitrarily adjustable. The basic principle is that the flow rate of cooling water to the sample surface is consistent with the production line design, so as to ensure that the experimental cooling rate is consistent with the production line under the premise that the cooling process is consistent with the production line. The nozzle diameter of the cooling spray box is in the range of 3~30mm, and the distance between the cooling spray box and the sample surface is in the range of 50~2200mm.

11. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, In step 1), the spacing, flow rate, and number of nozzles of the cooling spray boxes are arbitrarily adjustable to ensure that the experimental cooling rate is consistent with the production line, provided that the cooling process is consistent with the production line. The spacing of the cooling spray boxes ranges from 0 to 1.5 m, and the flow rate of the cooling spray boxes ranges from 0 to 300 m³ / h. 3 / h, the number of nozzles in the cooling spray box ranges from 1 to 200; the length of the cooling spray box is 100 to 6000 mm.

12. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, The vehicle is driven by either an electric motor or a traction drive.

13. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, The circular motion velocity of the sample, i.e., linear velocity or angular velocity, can be monitored in real time, and the velocity of the sample can be changed online according to the measured temperature data according to the predetermined cooling process, i.e., increasing the speed, decreasing the speed, or maintaining a constant speed.

14. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, The sample is heated either offline or online.

15. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 14, characterized in that, The offline heating method is as follows: after the sample is heated to the temperature required by the process, it is fixedly installed on the sample support platform. When it approaches the predetermined cooling temperature, the trolley is driven to move along the circular track, driving the sample to pass through the cooling spray box in sequence, that is, through the theoretically infinitely long cooling zone, to complete the cooling or heat treatment process. The online heating method is as follows: the sample is first fixedly installed on the sample support platform, and then heated. When the temperature required by the process is reached, the heating device is removed from the circular track area, and then the trolley is driven to move along the circular track to complete the cooling or heat treatment process.

16. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, Heating is achieved through resistance heating, where electrodes are used to clamp both sides of the sample, and a large current is applied to heat the sample directly online as a resistor; or, induction heating is used.

17. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 14, characterized in that, Heating is achieved through resistance heating, where electrodes are used to clamp both sides of the sample, and a large current is applied to heat the sample directly online as a resistor; or, induction heating is used.

18. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 15, characterized in that, Heating is achieved through resistance heating, where electrodes are used to clamp both sides of the sample, and a large current is applied to heat the sample directly online as a resistor; or, induction heating is used.

19. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 1 or 9, characterized in that, The sample is cooled by water or air.

20. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 9, characterized in that, In step 3), the flow rate range is 0~300m³. 3 / h, at equal flow intervals of 10~50m 3 / h to conduct experiments.

21. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as described in claim 9, characterized in that, In step 3), the cooling temperature range is 500~1000℃, and the experiment is carried out at equal temperature intervals of 40~60℃.

22. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as described in claim 9, characterized in that, In step 3), the cooling temperature range is 100~800℃, and the experiment is carried out at equal temperature intervals of 30~50℃.

23. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 9, characterized in that, In step 3), the cooling time is 0~20s, and the experiment is carried out at equal time intervals of 2~4s.

24. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box as described in claim 9, characterized in that, In step 5), the first cooling zone is set to a cooling temperature of 800~950℃, and the cooling interval between cooling zones is 4~12s.

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