Experimental measurement and control method for cooling process parameters after hot plate rolling

Abstract

An experimental measurement and control method for cooling process parameters after hot plate rolling comprises the following steps that (1) an annular track is combined with a trolley, the trolley bears a sample through a sample bearing table to do annular motion, and the annular track is an oval track comprising two parallel linear sections and two semicircular sections; at least one cooling spray box is arranged along the linear section track; the sample is heated to a set temperature through the heating device, and the temperature of the sample is measured through the temperature measuring device; (2) starting the trolley, and carrying the heated sample by the trolley at a specified constant process speed or at a certain accelerated speed in an accelerated manner to do annular motion; the sample passes through the cooling device, and jet flow ejected by the cooling spray box is sprayed onto the sample to cool the upper and lower surfaces of the sample simultaneously; acquiring the temperature of the sample in real time; the running speed of the sample is 0-25m / s, and the acceleration is 0-0.5 m / s < 2 >; the cooling temperature of the sample ranges from normal temperature to 1000 DEG C; the cooling starting temperature and the cooling stopping temperature are from normal temperature to 1000 DEG C; 3) performing performance and microscopic structure detection on the sample; and (4) repeating the step (2) to the step (3), and determining the cooling control parameters of which the performance and the structure meet the requirements according to the measured data.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy and relates to an experimental determination and control method of cooling process parameters after hot plate rolling. Background Art

[0002] Conventional cooling technology after hot plate rolling refers to changing the material's microstructure to meet the performance indicators of the hot plate by controlling the cooling rate, start cooling temperature and final cooling temperature after hot plate rolling.

[0003] Multi-path cooling technology after hot plate rolling refers to the use of phase change of materials to achieve fine grain strengthening and phase transformation strengthening by controlling reasonable process parameters and cooling paths, so as to obtain various steel products with excellent structure, high strength and high toughness, and achieve the goal of reducing costs by replacing metal with water. The cooling rate is also a very critical process control indicator.

[0004] The technology of uniform cooling of hot plate through thickness after rolling refers to achieving uniform cooling through thickness by controlling the water ratio of the upper and lower cooling spray boxes (hereinafter referred to as water ratio) to optimize the shape of the hot plate after cooling.

[0005] 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 the water spray cooling process, 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, only trial rolling and sampling performance testing at different spray box flow rates can be performed for evaluation. However, this results in longer cycle times, more scrap, and high trial rolling costs, which greatly limits the production capacity of the production line's high-strength steel with structural control.

[0006] Exploration and verification can also be conducted through post-rolling cooling on a hot rolling test mill. However, the current hot rolling test mill has significant differences from the field conditions, especially in terms of hot plate threading speed. To achieve the same speed as on-site, the cooling zone would have to be designed to be nearly 100 meters long, which is obviously unrealistic. In fact, there are currently no such test mills. Therefore, the process parameters obtained using the test mill often have significant differences in the performance of the hot plate after actual production on site. The process parameters obtained from the thermal simulator are even more difficult to convert into the field production process parameters. Moreover, 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 implement on the production line.

[0007] In summary, there is no experimental measurement and control method for hot plate cooling process parameters based on the experimental measurement and control method and device for hot plate cooling process parameters after rolling at home and abroad. Summary of the Invention

[0008] The purpose of the present invention is to provide an experimental measurement and control method for the cooling process parameters of hot plate after rolling. The cooling area of ​​the experimental device is configured according to the production line layout, and the optimal process parameters and feasible cooling control methods that meet the maximum process window of product production are determined through experiments; since the measurement and control method is implemented under conditions that are basically consistent with the actual working conditions of the production line, the product design output and production line process control are more accurate and efficient, which can effectively accelerate the speed of product research and development, improve the accuracy and stability of process control, and reduce the cost of production line trial production.

[0009] To achieve the above object, the technical solution of the present invention is:

[0010] An experimental determination and control method for cooling process parameters of hot plate after rolling, comprising the following steps:

[0011] 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a sample carrier. The circular track is an elliptical track comprising two parallel straight segments and two semicircular segments. At least one cooling spray box is provided along the straight segment track to cool the upper and / or lower surface of the sample. The sample is heated to a set temperature by a heating device arranged across the circular track or on the trolley. During this time, the sample temperature is measured by a temperature measuring device provided on the trolley.

[0012] 2) Start the trolley, which carries the heated sample in a circular motion at a specified process speed or at a certain acceleration. The sample passes through the cooling device, and the jet from the cooling spray box is sprayed onto the sample, cooling the upper and lower surfaces of the sample simultaneously. During this period, the sample is driven at a set speed through a theoretically infinite cooling zone to ensure that the sample is cooled from the start-of-cooling temperature to the set target temperature under conditions consistent with the production site conditions, and the sample temperature is monitored and obtained in real time. The sample running speed is: 0-25m / s, and the acceleration is:

[0013] 0~0.5m / s 2 ; Sample cooling temperature: room temperature ~ 1000℃; Cooling start temperature and cooling stop temperature:

[0014] Normal temperature ~ 1000℃;

[0015] 3) Conduct performance and microstructure tests on the samples;

[0016] 4) Repeat steps 2) to 3) and determine the cooling control parameters that meet the performance and structure requirements based on the measured data.

[0017] Preferably, the distance between the cooling spray box and the sample surface and the nozzle diameter are adjustable. The nozzle diameter of the cooling spray box ranges from 3 to 30 mm, and the distance between the cooling spray box and the sample surface ranges from 50 to 2200 mm. Preferably, the spacing between the cooling spray boxes is 0 to 1.5 m, and the flow rate of each cooling spray box is 0 to 300 m / s. 3 / h, the number of nozzles in each cooling spray box is 0 to 200.

[0018] Preferably, the cooling spray box includes an upper spray box and a lower spray box; the length of the cooling spray box ranges from 100 to 6000 mm.

[0019] Preferably, the trolley is driven by a motor or a traction drive.

[0020] Preferably, the circular motion speed of the sample, ie, the linear speed or angular speed, is monitored in real time, and the speed of the sample can be changed online according to the measured temperature data according to the predetermined cooling process, ie, the speed can be increased or decreased or kept constant.

[0021] Preferably, the sample is heated offline or online; preferably, the offline heating method is: after the sample is heated to the temperature required by the process, it is fixedly mounted on the sample carrier, and when it is close to the predetermined cooling temperature, the trolley is driven to move along the circular track, driving the sample to pass through the cooling device in sequence, that is, through a theoretically infinitely long cooling zone, to complete the cooling or heat treatment process; the online heating method is: the sample is first fixedly mounted on the sample carrier, and then heated. When the temperature required by the process is reached, the heating device is separated from the circular track area, and the trolley is driven to move along the circular track to complete the cooling or heat treatment process; preferably, the heating adopts a resistance heating method, that is, electrodes are used to clamp the two sides of the sample, and the sample is directly heated online as a resistor through a large current; or, an induction heating method is adopted; preferably, water cooling or air cooling is adopted for sample cooling.

[0022] Furthermore, the conventional cooling process parameters of hot plate after rolling of a certain steel grade and thickness specification are measured, that is, the cooling combination experiments at different flow rates, cooling start temperatures and cooling stop temperatures are carried out on the hot plate to measure the steel plate performance and cooling rate;

[0023] The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ;

[0024] The flow rate adjustment range of each cooling spray box is 0-300m3 / h, and the cooling experiment is carried out by increasing or decreasing the flow rate at intervals of 10-50m3 / h;

[0025] The cooling temperature range is 700-1000℃, and the cooling temperature is set to increase or decrease at temperature intervals of 40-60℃ for cooling experiments; the preferred cooling temperature is 800-950℃;

[0026] The cooling stop temperature range is from room temperature to 800°C, and the cooling stop temperature is set to increase or decrease at temperature intervals of 30 to 50°C for experiments; the cooling stop temperature is preferably 550 to 750°C.

[0027] In addition, the multi-path cooling process parameters of the hot plate post-rolling cooling process are measured, that is, a multi-path cooling experiment is conducted on the hot plate to measure the start-cooling temperature, flow rate, stop-cooling temperature and stop-cooling time between cooling zones in N cooling zones, the steel plate performance and the cooling rate of N cooling zones are measured, and the combination of the start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet the product performance is statistically calculated. The start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet the maximum process window of product production are determined according to the production line layout and process system; wherein,

[0028] The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ;

[0029] Design N cooling processes, N ≥ 2, and set each cooling process:

[0030] The cooling temperature is 500-1000°C, preferably increasing or decreasing by 40-60°C or other temperature intervals; the cooling temperature is preferably 800-950°C;

[0031] Cooling spray box flow rate is 0~300m 3 / h, preferably 10 to 50 m 3 / hThe experiment is carried out by increasing or decreasing the flow rate at intervals of equal flow rate;

[0032] The cooling stop temperature is 100-800°C, and the experiment is preferably conducted by increasing or decreasing the temperature at intervals of 30-50°C;

[0033] The cooling stop time is 0 to 20 seconds, and the experiment is preferably conducted by increasing or decreasing the time interval of 2 to 4 seconds; the preferred cooling stop time is 4 to 12 seconds;

[0034] During this period, the cooling rate is measured and calculated.

[0035] Furthermore, the determination of the optimal water ratio for uniform cooling of hot plate through thickness after rolling is carried out.

[0036] For conventional cooling of the hot plate, the cooling start temperature, cooling stop temperature, and flow rate corresponding to the optimal cooling rate are determined according to the method; the flow rates of the upper and lower spray boxes are adjusted within the range of flow rates corresponding to the optimal cooling rate, and a cooling experiment is conducted according to the determined cooling start temperature and cooling stop temperature. The upper and lower surface cooling curves are measured by embedded couplers, and the optimal upper and lower water ratio that satisfies uniform cooling of the steel plate thickness is determined based on the fit of the upper and lower surface cooling curves;

[0037] The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:3, preferably 50% to 100% for the upper spray box, 100% to 150% for the lower spray box, and a upper and lower water ratio of 1:1 to 1:2;

[0038] or;

[0039] For multi-path cooling of the hot plate, the flow rates of the upper and lower spray boxes are adjusted within a certain range of flow rates according to the flow rates corresponding to the optimal cooling rates of the N cooling zones determined by the method, and a cooling experiment is performed according to the determined cooling start temperature, cooling stop temperature and cooling stop time between the N cooling zones. The cooling curves of the upper and lower surfaces of the specimen are measured by embedded couplers, and the optimal upper and lower water ratio, cooling rate and upper and lower spray box flow rate parameters of the N cooling zones that meet the requirement of uniform cooling of the steel plate thickness are determined based on the principle that the fitting degree of the upper and lower surface cooling curves is above 80% and the fitting degree is maximized.

[0040] The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:3, preferably 50% to 100% for the upper spray box, 100% to 150% for the lower spray box, and a upper and lower water ratio of 1:1 to 1:2;

[0041] During the above experiments, the sample running speed was 0-25m / s and the acceleration was 0-0.5m / s 2 .

[0042] Furthermore, a cooling control method for hot plate post-rolling cooling spray box flow is not adjustable, that is, according to the optimal cooling rate, water ratio and production line cooling device layout determined by the experiment, different spray box opening mode configurations are performed on the experimental device, cooling experiments are carried out, and the optimal spray box opening mode parameters are obtained. The hot plate is controlled after rolling according to the spray box opening mode parameters; wherein, at least M cooling devices are set for each straight segment, M ≥ 3, and the cooling device interval range is 0 to M-2; each cooling device includes upper and lower cooling spray boxes; the sample running speed is 0 to 25 m / s, and the acceleration range is 0 to 0.5 m / s 2 ;

[0043] For conventional cooling control, according to the cooling start temperature, cooling stop temperature and optimal cooling rate determined by the method, the steel plate running speed is set according to the actual production line, and cooling experiments are carried out with different opening modes of the cooling spray box. That is, the cooling spray box is opened in several groups (the number of interval groups is 0 to 5) at intervals, and the cooling rate of the sample under different opening modes is measured. According to the experimental results, the spray box opening mode closest to the optimal cooling rate determined by the method is selected, and the corresponding hot plate production is subjected to conventional cooling control after rolling;

[0044] For multi-path cooling control, based on the optimal start-up temperature, cooling rate, stop-cooling temperature, and stop-cooling time between the N cooling zones determined by the method, the steel plate running speed is set according to the actual production line, and cooling experiments are conducted with different opening modes of the cooling spray box. That is, the cooling spray box is opened in a certain number of groups (the number of interval groups is 0 to 5), and the cooling rates under the different opening modes of the N cooling zones are measured. Based on the experimental results, the spray box opening mode that is closest to the optimal cooling rate of the N cooling zones determined by the method is selected, and conventional cooling control after rolling is performed on the corresponding hot plate production;

[0045] For thickness uniform cooling control, according to the optimal water ratio, optimal cooling rate and production line cooling device layout determined by the method, the water ratio of the upper and lower spray boxes under different interval opening modes (the number of interval groups is 0 to 5) is calculated, and the spray box opening mode that is close to the optimal water ratio is selected. The cooling rate under different spray box opening modes is measured. According to the experimental results, the spray box opening mode that is closest to the optimal cooling rate determined by the method is selected to perform thickness uniform cooling control for post-rolling cooling of the production line.

[0046] In addition, a cooling control method with adjustable flow rate for the hot plate post-rolling cooling spray box is proposed. This method converts the corresponding flow rate into the production line flow rate according to the flow density consistency principle based on the experimentally determined optimal cooling rate, flow rate, water ratio, and production line cooling device layout. This method obtains the optimal spray box flow rate parameters, calibrates the flow rate of the production line cooling spray box, and calculates the opening corresponding to the flow rate using the conventional linear interpolation method based on the calibration curve of each cooling spray box. This method then controls the post-rolling cooling of the corresponding hot plate.

[0047] For conventional cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method, the flow rate corresponding to the optimal cooling rate obtained in the experiment is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0048] For multi-path cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method, the flow rate corresponding to the optimal cooling rate of N cooling zones obtained from the experiment is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0049] For thickness uniform cooling control, according to the corresponding relationship between the water ratio and the upper and lower spray box flow rates determined by the method, the upper and lower spray flow rates corresponding to the optimal water ratio obtained in the experiment are converted into the upper and lower spray flow rates of the production line according to the flow density consistency principle. The flow rate range is 0~300m 3 / h;

[0050] Flow calibration is performed on the cooling spray boxes of the production line. The corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve is measured to form a calibration curve; the opening range is 0% to 100%, the opening interval is 5% to 20%, and 5% to 10% is preferred;

[0051] The flow rate of the production line is converted into the flow rate, and the opening corresponding to the flow rate is calculated by conventional linear interpolation according to the calibration curve of each cooling spray box, and the setting control is performed; the flow rate range is 0~300m 3 / h, opening range 0%~100%;

[0052] During the above experiments, the sample running speed was 0-25m / s and the acceleration was 0-0.5m / s 2 .

[0053] Beneficial effects of the present invention:

[0054] The present invention adopts a circular track combined with a trolley. The trolley carries the sample through the sample carrying platform to perform circular motion. The circular track is an elliptical track including two parallel straight segments and two semicircular segments. At least one cooling spray box is arranged along the straight segment track to achieve an infinitely long cooling zone at any workpiece speed.

[0055] Because the cooling process parameters obtained by the method of the present invention are measured on a cooling experimental device that closely matches the production line operating conditions, the optimal cooling rate that meets product performance and the optimal water ratio that ensures uniform cooling of the product thickness under the production line speed system can be accurately determined. By experimentally converting the optimal cooling rate and water ratio into a control method for the production line spray box flow rate or opening mode, the product design output can be made more closely aligned with the actual production line, making the product trial production process more accurate and efficient, thereby effectively reducing the production line trial production cost.

[0056] Since the cooling experimental device of the present invention is designed with infinitely long multiple cooling zones, it can meet the research needs of the maximum process window of multi-path cooling production of the production line, thereby improving the quality stability of products produced in batches of the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the layout of the cooling device in the embodiment of the method of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0059] See also Figure 1 The experimental determination and control method of the cooling process parameters of the hot plate after rolling according to the present invention comprises the following steps:

[0060] 1) A circular track 1 is combined with a trolley 2. The trolley 2 carries a sample 100 in a circular motion via a sample carrier 3. The circular track 1 is an elliptical track comprising two parallel straight segments and two semicircular segments. At least one cooling spray box 4 is provided along the straight segments to cool the upper and / or lower surfaces of the sample. The sample is heated to a set temperature by a heating device 5 arranged across the circular track 1 or on the trolley. During this time, the temperature of the sample 100 is measured by a temperature measuring device 61 provided on the trolley. The temperature measuring device 61 transmits data to a temperature measuring host 62 via wireless or wired means. The temperature measuring host 62 is connected to a controller PLC.

[0061] 2) Start the trolley, which carries the heated sample in a circular motion at a specified process speed or at a certain acceleration. The sample passes through the cooling device, and the jet from the cooling spray box is sprayed onto the sample, cooling the upper and lower surfaces of the sample simultaneously. During this period, the sample is driven at a set speed through a theoretically infinite cooling zone to ensure that the sample is cooled from the start-of-cooling temperature to the set target temperature under conditions consistent with the production site conditions, and the sample temperature is monitored and obtained in real time. The sample running speed is: 0-25m / s, and the acceleration is:

[0062] 0~0.5m / s 2 ; Sample cooling temperature: room temperature ~ 1000℃; Cooling start temperature and cooling stop temperature:

[0063] Normal temperature ~ 1000℃;

[0064] 3) Conduct performance and microstructure tests on the samples;

[0065] 4) Repeat steps 2) to 3) and determine the cooling control parameters that meet the performance and structure requirements based on the measured data.

[0066] Preferably, the distance between the cooling spray box and the sample surface and the nozzle diameter are adjustable. The nozzle diameter of the cooling spray box ranges from 3 to 30 mm, and the distance between the cooling spray box and the sample surface ranges from 50 to 2200 mm. Preferably, the spacing between the cooling spray boxes is 0 to 1.5 m, and the flow rate of each cooling spray box is 0 to 300 m / s. 3 / h, the number of nozzles in each cooling spray box is 0 to 200.

[0067] Preferably, the cooling spray box includes an upper spray box and a lower spray box; the length of the cooling spray box ranges from 100 to 6000 mm.

[0068] Preferably, the trolley is driven by a motor or a traction drive.

[0069] Preferably, the circular motion speed of the sample, ie, the linear speed or angular speed, is monitored in real time, and the speed of the sample can be changed online according to the measured temperature data according to the predetermined cooling process, ie, the speed can be increased or decreased or kept constant.

[0070] Preferably, the sample is heated offline or online; preferably, the offline heating method is: after the sample is heated to the temperature required by the process, it is fixedly mounted on the sample carrier, and when it is close to the predetermined cooling temperature, the trolley is driven to move along the circular track, driving the sample to pass through the cooling device in sequence, that is, through a theoretically infinitely long cooling zone, to complete the cooling or heat treatment process; the online heating method is: the sample is first fixedly mounted on the sample carrier, and then heated. When the temperature required by the process is reached, the heating device is separated from the circular track area, and the trolley is driven to move along the circular track to complete the cooling or heat treatment process; preferably, the heating adopts a resistance heating method, that is, electrodes are used to clamp the two sides of the sample, and the sample is directly heated online as a resistor through a large current; or, an induction heating method is adopted; preferably, water cooling or air cooling is adopted for sample cooling.

[0071] Furthermore, the conventional cooling process parameters of hot plate after rolling of a certain steel grade and thickness specification are measured, that is, the cooling combination experiments at different flow rates, cooling start temperatures and cooling stop temperatures are carried out on the hot plate to measure the steel plate performance and cooling rate;

[0072] The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ;

[0073] The flow rate adjustment range of each cooling spray box is 0-300m3 / h, and the cooling experiment is carried out by increasing or decreasing the flow rate at intervals of 10-50m3 / h;

[0074] The cooling temperature range is 700-1000℃, and the cooling temperature is set to increase or decrease at temperature intervals of 40-60℃ for cooling experiments; the preferred cooling temperature is 800-950℃;

[0075] The cooling stop temperature range is from room temperature to 800°C, and the cooling stop temperature is set to increase or decrease at temperature intervals of 30 to 50°C for experiments; the cooling stop temperature is preferably 550 to 750°C.

[0076] In addition, the multi-path cooling process parameters of the hot plate post-rolling cooling process are measured, that is, a multi-path cooling experiment is conducted on the hot plate to measure the start-cooling temperature, flow rate, stop-cooling temperature and stop-cooling time between cooling zones in N cooling zones, the steel plate performance and the cooling rate of N cooling zones are measured, and the combination of the start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet the product performance is statistically calculated. The start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet the maximum process window of product production are determined according to the production line layout and process system; wherein,

[0077] The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ;

[0078] Design N cooling processes, N ≥ 2, and set each cooling process:

[0079] The cooling temperature is 500-1000°C, preferably increasing or decreasing by 40-60°C or other temperature intervals; the cooling temperature is preferably 800-950°C;

[0080] Cooling spray box flow rate is 0~300m 3 / h, preferably 10 to 50 m 3 / hThe experiment is carried out by increasing or decreasing the flow rate at intervals of equal flow rate;

[0081] The cooling stop temperature is 100-800°C, and the experiment is preferably conducted by increasing or decreasing the temperature at intervals of 30-50°C;

[0082] The cooling stop time is 0 to 20 seconds, and the experiment is preferably conducted by increasing or decreasing the time interval of 2 to 4 seconds; the preferred cooling stop time is 4 to 12 seconds;

[0083] During this period, the cooling rate is measured and calculated.

[0084] Furthermore, the optimal water ratio for uniform cooling in the thickness direction of hot plate after rolling was determined.

[0085] For conventional cooling of the hot plate, the cooling start temperature, cooling stop temperature, and flow rate corresponding to the optimal cooling rate are determined according to the method; the flow rates of the upper and lower spray boxes are adjusted within the range of flow rates corresponding to the optimal cooling rate, and a cooling experiment is conducted according to the determined cooling start temperature and cooling stop temperature. The upper and lower surface cooling curves are measured by embedded couplers, and the optimal upper and lower water ratio that satisfies uniform cooling of the steel plate thickness is determined based on the fit of the upper and lower surface cooling curves;

[0086] The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:3, preferably 50% to 100% for the upper spray box, 100% to 150% for the lower spray box, and a upper and lower water ratio of 1:1 to 1:2;

[0087] or;

[0088] For multi-path cooling of the hot plate, the flow rates of the upper and lower spray boxes are adjusted within a certain range of flow rates according to the flow rates corresponding to the optimal cooling rates of the N cooling zones determined by the method, and a cooling experiment is performed according to the determined cooling start temperature, cooling stop temperature and cooling stop time between the N cooling zones. The cooling curves of the upper and lower surfaces of the specimen are measured by embedded couplers, and the optimal upper and lower water ratio, cooling rate and upper and lower spray box flow rate parameters of the N cooling zones that meet the requirement of uniform cooling of the steel plate thickness are determined based on the principle that the fitting degree of the upper and lower surface cooling curves is above 80% and the fitting degree is maximized.

[0089] The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:3, preferably 50% to 100% for the upper spray box, 100% to 150% for the lower spray box, and a upper and lower water ratio of 1:1 to 1:2;

[0090] During the above experiments, the sample running speed was 0-25m / s and the acceleration was 0-0.5m / s 2 .

[0091] Furthermore, a cooling control method for hot plate post-rolling cooling spray box flow is not adjustable, that is, according to the optimal cooling rate, water ratio and production line cooling device layout determined by the experiment, different spray box opening mode configurations are performed on the experimental device, cooling experiments are carried out, and the optimal spray box opening mode parameters are obtained. The hot plate is controlled after rolling based on the spray box opening mode parameters; wherein, at least M cooling devices are set for each straight segment, M ≥ 3, and the cooling device interval range is 0 to M-2; each cooling device includes upper and lower cooling spray boxes; the sample running speed is 0 to 25 m / s, and the acceleration range is 0 to 0.5 m / s 2 ;

[0092] For conventional cooling control, according to the cooling start temperature, cooling stop temperature and optimal cooling rate determined by the method, the steel plate running speed is set according to the actual production line, and cooling experiments are carried out with different opening modes of the cooling spray box. That is, the cooling spray box is opened in several groups (the number of interval groups is 0 to 5) at intervals, and the cooling rate of the sample under different opening modes is measured. According to the experimental results, the spray box opening mode closest to the optimal cooling rate determined by the method is selected, and the corresponding hot plate production is subjected to conventional cooling control after rolling;

[0093] For multi-path cooling control, based on the optimal start-up temperature, cooling rate, stop-cooling temperature, and stop-cooling time between N cooling zones determined by the method, the steel plate running speed is set according to the actual production line, and cooling experiments are conducted with different opening modes of the cooling spray box. That is, the cooling spray box is opened in a certain number of groups (the number of interval groups is 0 to 5), and the cooling rates under different opening modes of the N cooling zones are measured. Based on the experimental results, the spray box opening mode that is closest to the optimal cooling rate of the N cooling zones determined by the method is selected, and conventional cooling control is performed on the corresponding hot plate production after rolling;

[0094] For thickness uniform cooling control, according to the optimal water ratio, optimal cooling rate and production line cooling device layout determined by the method, the water ratio of the upper and lower spray boxes under different interval opening modes (the number of interval groups is 0 to 5) is calculated, and the spray box opening mode that is close to the optimal water ratio is selected. The cooling rate under different spray box opening modes is measured. According to the experimental results, the spray box opening mode that is closest to the optimal cooling rate determined by the method is selected to perform thickness uniform cooling control for post-rolling cooling of the production line.

[0095] Furthermore, a cooling control method with adjustable flow rate for the hot plate post-rolling cooling spray box is proposed. This method converts the corresponding flow rate into the production line flow rate according to the flow density consistency principle based on the experimentally determined optimal cooling rate, flow rate, water ratio, and production line cooling device layout. This method obtains the optimal spray box flow rate parameters, calibrates the flow rate of the production line cooling spray box, and calculates the opening corresponding to the flow rate through conventional linear interpolation according to the calibration curve of each cooling spray box. This method then controls the post-rolling cooling of the corresponding hot plate.

[0096] For conventional cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method, the flow rate corresponding to the optimal cooling rate obtained in the experiment is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0097] For multi-path cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method, the flow rate corresponding to the optimal cooling rate of N cooling zones obtained from the experiment is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0098] For thickness uniform cooling control, according to the corresponding relationship between the water ratio and the upper and lower spray box flow rates determined by the method, the upper and lower spray flow rates corresponding to the optimal water ratio obtained in the experiment are converted into the upper and lower spray flow rates of the production line according to the flow density consistency principle. The flow rate range is 0~300m 3 / h;

[0099] Flow calibration is performed on the cooling spray boxes of the production line. The corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve is measured to form a calibration curve; the opening range is 0% to 100%, the opening interval is 5% to 20%, and 5% to 10% is preferred;

[0100] The flow rate of the production line is converted into the flow rate, and the opening corresponding to the flow rate is calculated by conventional linear interpolation according to the calibration curve of each cooling spray box, and the setting control is performed; the flow rate range is 0~300m 3 / h, opening range 0%~100%;

[0101] During the above experiments, the sample running speed was 0-25m / s and the acceleration was 0-0.5m / s 2 .

[0102] Example 1

[0103] The experimental determination and control method of conventional cooling process parameters after hot plate rolling includes:

[0104] The conventional cooling process parameters were experimentally determined for a certain type of steel with a thickness of 4.5 mm;

[0105] An experimental scheme was designed according to different combinations of flow rates, cooling start temperatures, and cooling stop temperatures. A steel plate buried cooling experiment was carried out. The steel plate running speed was set to 8 m / s according to the actual production line. The cooling rate and performance of the steel plate after cooling under different process parameter combinations were measured, and the experimental results were obtained, as shown in Table 1.

[0106] Table 1 Experimental schemes of different process parameter combinations and cooling rates and properties of the steel plates after cooling

[0107]

[0108] The experimental results of the cooling rate and performance of the steel plates after cooling under different process parameter combinations were analyzed. Serial numbers 5-9 and 11-12 met the conditions. Taking into account the process conditions before and after the production line and the cooling control window, serial number 8 was finally selected as the production line process parameters, that is, the start cooling temperature was 850℃, the stop cooling temperature was 600℃ and the cooling rate was 32℃ / s.

[0109] Example 2

[0110] The experimental determination and control method of multi-path cooling process parameters after hot plate rolling includes:

[0111] An experiment was conducted on a 4.5mm thick steel grade with two cooling zones to determine the multi-path cooling process parameters.

[0112] An experimental scheme was designed according to different combinations of upper and lower spray flow rates, cooling start temperature, cooling stop temperature and cooling stop time in the two cooling zones. A steel plate buried cooling experiment was carried out. The steel plate running speed was set to 8m / s according to the actual production line. The performance of the cooled steel plate and the cooling rate of the two cooling zones under different process parameter combinations were measured, and the experimental results were obtained, as shown in Table 2.

[0113] Table 2 Experimental schemes with different process parameter combinations and cooling rates and properties of the steel plates after cooling

[0114]

[0115] The experimental results of cooling rate and performance of steel plates after cooling under different process parameter combinations were analyzed. Serial numbers 5-6 met the conditions. Taking into account the process conditions before and after the production line and the cooling control window, serial number 5 was finally selected as the production line process parameters, that is, the first cooling zone opening temperature was 870℃, the first cooling zone upper spray flow rate was 42m 3 / h, the first cooling zone downward spray flow rate is 50m 3 / h, the first cooling zone stop temperature is 680℃, the first cooling zone cooling rate is 150℃ / s, the stop cooling time is 5 seconds, the second cooling zone stop temperature is 680℃, the second cooling zone upper spray flow rate is 25m 3 / h, the first cooling zone spray flow rate is 30m 3 / h, the first cooling zone stop temperature is 560℃ and the first cooling zone cooling rate is 75℃ / s.

[0116] Example 3

[0117] The experimental determination method of the process parameters of uniform cooling in the thickness direction after hot plate rolling includes:

[0118] The experimental scheme was designed according to different combinations of upper and lower spray boxes with different flow rates and water ratios. The starting cooling temperature was 850℃ and the final cooling temperature was 600℃. The steel plate buried cooling experiment was carried out. The steel plate running speed was set to 12m / s according to the actual production line. The fitting degree of the cooling curve of the steel plate after cooling under different flow rates and water ratios of the upper and lower spray boxes was measured, and the experimental results were obtained, as shown in Table 3.

[0119] Table 3 Fitting degree of cooling curve of steel plate after cooling at different flow rates of upper and lower spray boxes

[0120]

[0121] The fitting degree of the cooling curve of the steel plate after cooling under different combinations of upper and lower spray boxes with different flow rates and water ratios was analyzed. Taking into account the process conditions before and after the production line and the cooling control window, the sequence number 4 was finally selected as the production line process parameter, that is, the upper spray flow rate of 13.5m 3 / h, downward spray flow rate 18m 3 / h and water ratio is 1:1.33.

[0122] Example 4

[0123] Conventional cooling control methods for hot plate post-rolling cooling spray box flow that cannot be adjusted include:

[0124] The optimal cooling rate of a 4.5mm thick steel grade was determined to be 35℃ / s when the starting cooling temperature was 850℃ and the final cooling temperature was 600℃.

[0125] The steel plate buried cooling experiment was carried out according to different spray box opening modes. The steel plate running speed was set to 8m / s according to the actual production line. Since the spray box flow rate of the production line is not adjustable, the cooling rate of the steel plate after cooling with different spray box opening modes is obtained. The experimental results in Table 4 are given.

[0126] Table 4 Cooling speed of upper and lower spray boxes in different opening modes (1 is on, 0 is off)

[0127]

[0128] Based on the degree of proximity between the cooling rate of the steel plate under different spray box opening modes and the optimal cooling rate, the spray box opening mode No. 3 was finally selected as the production line process parameter, and the post-rolling cooling of the production line was set and controlled to obtain strip steel with qualified performance.

[0129] Example 5

[0130] A multi-path cooling control method for a hot plate after rolling with a non-adjustable cooling spray box flow rate includes:

[0131] In the multi-path cooling experiment of two cooling zones of a certain 3mm thick steel, the starting cooling temperature of the first cooling zone was 870℃, the final cooling temperature was 680℃, and the optimal cooling rate was 150℃ / s. The starting cooling temperature of the second cooling zone was 680℃, the final cooling temperature was 560℃, and the optimal cooling rate was 70℃ / s.

[0132] The steel plate embedded cooling experiment was carried out according to different spray box opening modes. The steel plate running speed was set to 8m / s according to the actual production line. Since the spray box flow rate of the production line is not adjustable, the cooling rate and performance of the steel plate after cooling with different spray box opening modes of the experimental device were measured, and the experimental results in Tables 5 and 6 were obtained.

[0133] Table 5 Cooling rate of the first cooling zone under different opening modes of the upper and lower spray boxes (1 is on, 0 is off)

[0134]

[0135] According to the steel plate performance under different spray box opening modes and the degree of proximity of the cooling rate to the optimal cooling rate, the spray box opening mode No. 2 in Table 5 was finally selected as the production line process parameter for the first cooling zone.

[0136] Table 6 Cooling rate of the second cooling zone under different opening modes of the upper and lower spray boxes (1 is on, 0 is off)

[0137]

[0138] According to the steel plate performance under different spray box opening modes and the degree of proximity of the cooling rate to the optimal cooling rate, the spray box opening mode No. 2 in Table 6 was finally selected as the production line process parameter of the second cooling zone.

[0139] According to the spray box opening mode of No. 2 in Table 5 and Table 6 selected by the cooling experiment, the post-rolling cooling of the production line was set and controlled, and strip steel with qualified performance was obtained.

[0140] Example 6

[0141] A method for controlling uniform cooling of a hot plate after rolling with a non-adjustable flow rate of a cooling spray box, comprising:

[0142] Experimental results show that the optimal water ratio for uniform cooling of a certain type of steel with a thickness of 3 mm is 1:1.3, and the optimal cooling rate is 32°C / s.

[0143] The water ratio calculation of the upper and lower spray boxes of the experimental device in different opening modes is shown in Table 7

[0144] Table 7 Water ratio of upper and lower spray boxes in different opening modes (1 is on, 0 is off)

[0145]

[0146] According to the calculation results in Table 7, five spray box opening modes (numbered 2-6) were selected to carry out the steel plate buried cooling experiment. The steel plate running speed was set to 12 m / s according to the actual production line, and the steel plate cooling rate under different spray box opening modes was obtained.

[0147] The cooling rate calculations of the upper and lower spray boxes of the experimental device under different opening modes are shown in Table 8.

[0148] Table 8 Cooling speed of upper and lower spray boxes in different opening modes (1 is on, 0 is off)

[0149]

[0150]

[0151] According to the experimental results in Table 8, the cooling rates of the samples under different opening modes were compared, and the spray box opening mode closest to the optimal cooling rate of 32°C / s was selected, that is, the spray box opening mode No. 3. The production line was set to control the uniform cooling setting in the thickness direction, and a strip with qualified performance and good plate shape was obtained.

[0152] Example 7

[0153] Conventional cooling control methods with adjustable flow rate of the cooling spray box after hot plate rolling include:

[0154] The optimal flow rate for conventional cooling determined by experiment is 72m 3 / h;

[0155] After calibrating the flow control valve of the production line, the flow rate is 80m when the opening is 70%. 3 / h, the flow rate is 65m when the opening is 60% 3 / h, for 72m 3 Linear interpolation of the opening value of the flow rate / h: (When applied to the production line, to ensure smooth production, piecewise linear interpolation is selected when performing the interpolation calculation of the flow conversion opening. As long as the opening interval of the calibration curve is small enough, the accuracy of the piecewise linear interpolation is guaranteed.)

[0156] Production line flow control valve opening value = (72-65) × (70%-60%) / (80-65) + 60% = 66.6%;

[0157] The flow regulating valve of the production line was set and conventional cooling control was performed according to this opening value, and strip steel with qualified performance was obtained.

[0158] Example 8

[0159] A multi-path cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling, comprising:

[0160] The experimentally determined flow rate of the spray box in the first cooling zone of the multi-path cooling is 168m 3 / h, the flow rate of the lower spray box is 200m 3 / h, the flow rate of the upper spray box in the second cooling zone is 100m 3 / h, the flow rate of the lower spray box is 120m 3 / h;

[0161] After calibration and linear interpolation of the production line flow control valve, we get:

[0162] The opening value of the upper spray box regulating valve in the first cooling zone = 81%;

[0163] The opening value of the lower spray box regulating valve in the first cooling zone = 82%;

[0164] The opening value of the upper spray box regulating valve in the second cooling zone = 46.7%;

[0165] The opening value of the lower spray box regulating valve in the second cooling zone = 46.3%;

[0166] The flow regulating valve of the production line was set and multi-path cooling was controlled according to this opening value, and strip steel with qualified performance was obtained.

[0167] Example 9

[0168] A method for controlling uniform cooling of a hot plate after rolling with an adjustable flow rate of a cooling spray box, comprising:

[0169] The experimentally determined flow rate of the thick uniform cooling spray box is 54m 3 / h, the flow rate of the lower spray box is 72m 3 / h;

[0170] After calibrating the flow control valve of the production line, we get:

[0171] When the upper spray box is 55% open, the flow rate is 55m 3 / h, the flow rate is 50m when the opening is 50% 3 / h, for 54m 3 Linear interpolation of the opening value of the flow rate / h:

[0172] Opening value = (54-50) × (55%-50%) / (55-50) + 50% = 54%;

[0173] When the lower spray box is 70% open, the flow rate is 80m 3 / h, the flow rate is 65m when the opening is 60% 3 / h, for 72m 3 Linear interpolation of the opening value of the flow rate / h:

[0174] Opening value = (72-65) × (70%-60%) / (80-65) + 60% = 66.6%;

[0175] The flow valve of the production line is set according to this opening value and the uniform cooling in the thickness direction is controlled to obtain a strip with good plate shape.

Claims

1. An experimental determination and control method for the cooling process parameters of hot plate after rolling, characterized in that: The steps include: 1) A circular track combined with a trolley is used. The trolley carries the sample in a circular motion via a sample carrier. The circular track is an elliptical track comprising two parallel straight segments and two semicircular segments. At least one cooling spray box is provided along the straight segment track to cool the upper and / or lower surface of the sample. The sample is heated to a set temperature by a heating device arranged across the circular track or on the trolley. During this time, the sample temperature is measured by a temperature measuring device provided on the trolley. 2) Start the trolley, which carries the heated sample in a circular motion at a specified process speed or at a certain acceleration; the sample passes through the cooling device, and the jet from the cooling spray box is sprayed onto the sample, cooling the upper and lower surfaces of the sample at the same time; during this period, the sample is driven at a set speed through a theoretically infinite cooling zone to ensure that the sample is cooled from the start-of-cooling temperature to the set target temperature under conditions consistent with the working conditions of the production site, and the sample temperature is monitored and obtained in real time; the sample running speed is: 0-25m / s, acceleration: 0-0.5m / s 2 ; Sample cooling temperature: room temperature ~ 1000℃; cooling start temperature and cooling stop temperature: room temperature ~ 1000℃; 3) Conduct performance and microstructure tests on the samples; 4) Repeat steps 2) to 3) and determine the cooling control parameters that meet the performance and structure requirements based on the measured data.

2. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 is characterized in that: The distance between the cooling spray box and the sample surface and the nozzle diameter can be adjusted arbitrarily. The nozzle diameter of the cooling spray box ranges from 3 to 30 mm, and the distance between the cooling spray box and the sample surface ranges from 50 to 2200 mm. Preferably, the spacing between the cooling spray boxes is 0 to 1.5 m, and the flow rate of each cooling spray box is 0 to 300 m 3 / h, the number of nozzles in each cooling spray box is 0 to 200.

3. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 or 2, characterized in that: The cooling spray box includes an upper spray box and a lower spray box; the length of the cooling spray box ranges from 100 to 6000 mm.

4. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 is characterized in that: The trolley is driven by motor or traction.

5. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 is characterized in that: The circular motion speed of the sample, i.e. the linear speed or angular speed, is monitored in real time, and the speed of the sample can be changed online according to the measured temperature data according to the predetermined cooling process, i.e. the speed can be increased or decreased or kept constant.

6. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 is characterized in that: The sample is heated offline or online; preferably, the offline heating method is: after the sample is heated to the temperature required by the process, it is fixedly mounted on the sample carrier, and when it is close to the predetermined cooling temperature, the trolley is driven to move along the circular track, driving the sample to pass through the cooling device in sequence, that is, through a theoretically infinitely long cooling zone, to complete the cooling or heat treatment process; the online heating method is: the sample is first fixedly mounted on the sample carrier, and then heated. When the temperature required by the process is reached, the heating device is separated from the circular track area, and the trolley is driven to move along the circular track to complete the cooling or heat treatment process; preferably, the heating adopts a resistance heating method, that is, electrodes are used to clamp the two sides of the sample, and the sample is directly heated online as a resistor through a large current; or, an induction heating method is adopted; preferably, water cooling or air cooling is adopted for sample cooling.

7. The experimental determination and control method of the cooling process parameters of hot plate after rolling according to claim 1 is characterized in that: The conventional cooling process parameters of hot plate after rolling of a certain steel grade and thickness specification are measured, that is, the cooling combination experiment of the hot plate at different flow rates, cooling start temperature and cooling stop temperature is carried out to measure the steel plate performance and cooling rate; The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ; The flow rate adjustment range of each cooling spray box is 0~300m 3 / h, according to 10~50m 3 / h and other flow rate intervals are set to increase or decrease to conduct cooling experiments; The cooling temperature range is 700-1000℃, and the cooling temperature is set to increase or decrease at temperature intervals of 40-60℃ for cooling experiments; the preferred cooling temperature is 800-950℃; The cooling stop temperature range is from room temperature to 800°C, and the cooling stop temperature is set to increase or decrease at temperature intervals of 30 to 50°C for experiments; the cooling stop temperature is preferably 550 to 750°C.

8. The experimental determination and control method of the cooling process parameters after hot plate rolling according to claim 1 is characterized in that: Determination of multi-path cooling process parameters of hot plate post-rolling cooling process, i.e., multi-path cooling experiment of hot plate with N cooling zones’ start-cooling temperature, flow rate, stop-cooling temperature and stop-cooling time between cooling zones is carried out to measure steel plate performance and cooling rate of N cooling zones, and statistical combination of start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet product performance is calculated, and the start-cooling temperature, cooling rate, stop-cooling temperature and stop-cooling time between cooling zones that meet the maximum process window of product production are determined according to production line layout and process system; wherein, The sample running speed is 0~25m / s, and the acceleration is 0~0.5m / s 2 ; Design N cooling processes, N ≥ 2, and set each cooling process: The cooling temperature is 500-1000°C, preferably increasing or decreasing by 40-60°C or other temperature intervals; the cooling temperature is preferably 800-950°C; Cooling spray box flow rate is 0~300m 3 / h, preferably 10 to 50 m 3 / hThe experiment is carried out by increasing or decreasing the flow rate at intervals of The cooling stop temperature is 100-800°C, and the experiment is preferably conducted by increasing or decreasing the temperature at intervals of 30-50°C; The cooling stop time is 0 to 20 seconds, and the experiment is preferably conducted by increasing or decreasing the time interval of 2 to 4 seconds; the preferred cooling stop time is 4 to 12 seconds; During this period, the cooling rate is measured and calculated.

9. The experimental determination and control method of the cooling process parameters of hot plate after rolling according to claim 7 or 8, characterized in that: Determination of the optimal water ratio for uniform cooling in thickness direction after hot plate rolling: For conventional cooling of the hot plate, the cooling start temperature, cooling stop temperature, and flow rate corresponding to the optimal cooling rate are determined according to the method of claim 7; the flow rates of the upper and lower spray boxes are adjusted within the range of flow rates corresponding to the optimal cooling rate, and a cooling experiment is conducted according to the determined cooling start temperature and cooling stop temperature. The upper and lower surface cooling curves are measured by embedded couplers, and the optimal upper and lower water ratio that satisfies uniform cooling of the steel plate thickness is determined based on the principle that the upper and lower surface cooling curves have a fitting degree of more than 80% and a maximum fitting degree; The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:3, preferably 50% to 100% for the upper spray box, 100% to 150% for the lower spray box, and a upper and lower water ratio of 1:1 to 1:2; or; For multi-path cooling of the hot plate, the flow rates corresponding to the optimal cooling rates of the N cooling zones are determined according to the method of claim 8, the flow rates of the upper and lower spray boxes are adjusted within a certain range of flow rates, and a cooling experiment is conducted according to the determined start-up temperature, stop-cooling temperature, and stop-cooling time between the N cooling zones. The cooling curves of the upper and lower surfaces of the specimen are measured by embedded couplers, and the optimal upper and lower water ratios, cooling rates, and upper and lower spray box flow rate parameters of the N cooling zones that meet the requirement of uniform cooling of the steel plate thickness are determined based on the principle that the fitting degree of the upper and lower surface cooling curves is greater than 80% and the fitting degree is maximized; The flow rate adjustment range is 50% to 150% of the measured flow rate value, with an upper and lower water ratio of 3:1 to 1:

3. Preferably, the upper spray box is 50% to 100%, the lower spray box is 100% to 150%, and the upper and lower water ratio is 1:1 to 1:

2. During the above experiment, the sample running speed is 0 to 25 m / s and the acceleration is 0 to 0.5 m / s. 2 .

10. The experimental determination and control method of the cooling process parameters of hot plate after rolling according to claim 7, 8 or 9, characterized in that: A cooling control method for hot plate post-rolling cooling spray box flow is not adjustable, that is, according to the optimal cooling rate, water ratio and production line cooling device layout determined by the experiment, different spray box opening mode configurations are performed on the experimental device, cooling experiments are carried out, and the optimal spray box opening mode parameters are obtained. The hot plate is then cooled after rolling according to the spray box opening mode parameters; wherein, at least M cooling devices are set for each straight segment, M ≥ 3, and the cooling device interval range is 0 to M-2; each cooling device includes upper and lower cooling spray boxes; the sample running speed is 0 to 25 m / s, and the acceleration range is 0 to 0.5 m / s 2 ; For conventional cooling control, the cooling start temperature, cooling stop temperature, and optimal cooling rate determined by the method according to claim 7, and the steel plate running speed are set according to the actual production line, and cooling experiments are conducted with different opening modes of the cooling spray box, that is, the cooling spray box is opened in a plurality of groups at intervals, with the number of interval groups being 0 to 5; the cooling rate of the sample under different opening modes is measured, and based on the experimental results, the spray box opening mode closest to the optimal cooling rate determined by the method according to claim 7 is selected, and conventional cooling control after rolling is performed on the corresponding hot plate production; For multi-path cooling control, according to the method of claim 8, the optimal start-up temperature, cooling rate, stop-cooling temperature and stop-cooling time between the N cooling zones are determined, and the steel plate running speed is set according to the actual production line. The cooling spray box is set to different opening modes for cooling experiments, that is, the cooling spray box is opened in several groups at intervals, and the number of interval groups is 0 to 5; the cooling rate under the different opening modes of the N cooling zones is measured. Based on the experimental results, the spray box opening mode that is closest to the optimal cooling rate of the N cooling zones determined by the method of claim 8 is selected, and the corresponding hot plate production is subjected to conventional cooling control after rolling; For thickness uniform cooling control, according to the optimal water ratio, optimal cooling rate and production line cooling device layout determined by the method according to claim 9, the water ratio of the upper and lower spray boxes under different interval opening modes is calculated, and the number of interval groups is 0 to 5; the spray box opening mode that is close to the optimal water ratio is selected, and the cooling rate under different spray box opening modes is measured. According to the experimental results, the spray box opening mode that is closest to the optimal cooling rate determined by the method according to claim 9 is selected to perform thickness uniform cooling control for post-rolling cooling of the production line.

11. The method for experimental determination and control of cooling process parameters of hot plate after rolling according to claim 7, 8 or 9, characterized in that: A cooling control method with adjustable flow rate for hot plate post-rolling cooling spray boxes is developed. This involves converting the corresponding flow rate into production line flow rate based on the flow density consistency principle, based on the experimentally determined optimal cooling rate, flow rate, water ratio, and production line cooling device layout. This results in optimal spray box flow parameters. The production line cooling spray boxes are then calibrated for flow rate. Based on the calibration curve for each cooling spray box, the corresponding opening is calculated through linear interpolation to control post-rolling cooling of the corresponding hot plate. For conventional cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method of claim 7, the flow rate corresponding to the optimal cooling rate obtained by experiment is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h; For multi-path cooling control, according to the corresponding relationship between cooling rate and flow rate determined by the method described in claim 8, the flow rate corresponding to the optimal cooling rate of N cooling zones obtained experimentally is converted into production line flow rate according to the flow density consistency principle, and the flow rate range is 0-300m 3 / h; For thickness uniform cooling control, according to the corresponding relationship between the water ratio and the upper and lower spray box flow rate determined by the method described in claim 9, the upper and lower spray flow rates corresponding to the optimal water ratio obtained in the experiment are converted into the upper and lower spray flow rates of the production line according to the principle of consistent flow density. The flow rate range is 0 to 300m 3 / h; Flow calibration is performed on the cooling spray boxes of the production line. The corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve is measured to form a calibration curve; the opening range is 0% to 100%, the opening interval is 5% to 20%, and 5% to 10% is preferred; The flow rate of the production line is converted into the flow rate, and the opening corresponding to the flow rate is calculated by linear interpolation according to the calibration curve of each cooling spray box, and the setting control is performed; the flow rate range is 0~300m 3 / h, opening range 0%~100%; During the above experiments, the sample running speed was 0-25m / s and the acceleration was 0-0.5m / s 2 .

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