Cooling control method capable of adjusting flow of cooling spray box after hot plate rolling

Abstract

The invention relates to a cooling control method capable of adjusting the flow of a cooling spray box after hot plate rolling, which realizes an infinitely long cooling area at any workpiece speed through a mode of combining an annular runway with a trolley, and converts corresponding flow into production line flow according to a flow density consistency principle according to the optimal cooling rate, flow, water ratio and production line cooling spray box layout determined by an experiment. And the optimal flow parameter of the cooling spray box is obtained, flow calibration is carried out on the cooling spray box of the production line, the opening degree corresponding to the flow is calculated according to the calibration curve of each cooling spray box, and cooling control is carried out on the corresponding hot plate after rolling. Due to the fact that the cooling control method is implemented under the condition basically consistent with the actual working condition of the production line, product design output and production line process control are more accurate and efficient, the product research and development speed can be effectively increased, the process control precision can be effectively improved, and the production line trial-manufacturing cost can be effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a cooling control method with adjustable flow of a cooling spray box after hot plate rolling. Background Art

[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. The post-rolling cooling zone of most production lines is about 100 meters long, and the number of upper and lower spray boxes ranges from dozens to hundreds, which perform symmetrical water cooling on the upper and lower surfaces of the hot plate.

[0003] 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.

[0004] 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 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 change of the material, the effects of fine grain strengthening and phase change strengthening are achieved, and various steel products with excellent structure, high strength and high toughness can be obtained, achieving the goal of reducing costs by replacing metal with water.

[0005] 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.

[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 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.

[0007] 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.

[0008] In summary, there is no cooling control method with adjustable flow rate of hot plate post-rolling cooling spray box based on a method and device for realizing infinite cooling zone at arbitrary workpiece speed at home and abroad. Summary of the Invention

[0009] The purpose of the present invention is to provide a cooling control method with adjustable flow rate of a cooling spray box for hot plates after rolling. By combining a circular runway with a trolley method, an infinitely long cooling zone at any workpiece speed is realized. According to the optimal cooling rate, flow rate, water ratio and production line cooling spray box layout determined by experiments, the corresponding flow rate is converted into the production line flow rate according to the flow density consistency principle, and the optimal spray box flow parameter is obtained. The flow rate of the production line cooling spray box is calibrated, and the opening corresponding to the flow rate is calculated according to the calibration curve of each cooling spray box, and the post-rolling cooling control of the corresponding hot plate is performed. Since the cooling control method of the present invention 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 product research and development speed, improve the process control accuracy, and reduce the production line trial production cost.

[0010] To achieve the above object, the technical solution of the present invention is:

[0011] A cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling, comprising 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 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. Each cooling spray box includes an upper and a lower spray box. 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.

[0013] 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 spray box, 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 production line working conditions, and the sample temperature and cooling rate are monitored and obtained in real time; wherein,

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

[0015] The flow rate adjustment range of each cooling spray box is 0~300m 3 / h, preferably, 10 to 50 m3 / h and other flow rate intervals are set to increase or decrease to conduct cooling experiments;

[0016] The cooling temperature is 700-1000°C. Preferably, the cooling experiment is performed by increasing or decreasing the temperature at intervals of 40-60°C.

[0017] The cooling stop temperature is from room temperature to 800°C. Preferably, the experiment is conducted by increasing or decreasing the temperature by 30-50°C.

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

[0019] 3) Test the performance and microstructure of the samples;

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

[0021] 5) The flow rate corresponding to the optimal cooling rate obtained in the experiment is converted into the production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0022] 6) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%;

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

[0024] Preferably, in step 2), based on the start cooling temperature T1, stop cooling temperature T2 and cumulative cooling time t recorded during the experimental process, the cooling rate CR of the steel plate is calculated as follows: (start cooling temperature T1 - stop cooling temperature T2) / cumulative cooling time t, where the cumulative cooling time t is in seconds; the cooling rate range is 0 to 1000°C / s.

[0025] Preferably, in step 3), the performance Xact of the steel plate is measured by a detection device. Xact is considered qualified if it is within the positive and negative tolerance range allowed by the target performance Xtar, that is, ΔX1≤(Xact-Xtar)≤ΔX2, wherein ΔX1: negative tolerance, ΔX2: positive tolerance, and the target performance and positive and negative tolerance range of the steel plate are determined by user needs.

[0026] Preferably, in step 4), the experimental results under different combinations of cooling rate, start cooling temperature and stop cooling temperature are counted, and the combination that meets the product performance is selected for comprehensive comparison. The optimal cooling rate, start cooling temperature and stop cooling temperature that meet the maximum process window of product production are determined according to the production line layout and process system; the preferred start cooling temperature is 800-950°C, and the preferred stop cooling temperature is 550°C-750°C.

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

[0028] 1) A circular track combined with a trolley is used. The trolley carries the sample through a carrier platform and performs circular motion. The circular track is an elliptical track comprising two parallel straight segments and semicircular arc segments at both ends. At least one cooling spray box is provided along the straight segment track to cool the upper and / or lower surfaces of the sample. The carrier platform for fixing the sample is hollowed out in the middle, leaving the upper and lower surfaces of the sample unobstructed. The jet ejected by the cooling spray box is directly sprayed onto the sample, forming two linear cooling zones. The sample is heated to a set temperature by a heating device arranged across the circular track or on the trolley. During this period, the temperature of the sample is measured by a temperature measuring device provided on the trolley.

[0029] 2) The driving trolley drives the sample to reach the specified process speed, maintains a constant speed or accelerates at a certain acceleration, and passes through a theoretically infinite cooling zone in a moving state to ensure that the sample is cooled from the start-cooling temperature to the target temperature under conditions basically consistent with the on-site working conditions. The cooling process temperature is detected in real time, the cooling process time is accumulated in real time, and the cooling stop time is precisely controlled;

[0030] 3) For a sample of a certain steel grade and thickness specification, a cooling combination experiment with different flow rates, cooling stop temperatures and cooling stop times in N cooling zones was conducted to determine the cooling rate and steel plate properties; the flow rate range was 0 to 300 m 3 / h, preferably at equal flow intervals of 10 to 50 m 3 / h, the cooling temperature range is 500 ~ 1000 ℃, preferably at an equal temperature interval of 40 ~ 60 ℃, the cooling temperature range is 100 ~ 800 ℃, preferably at an equal temperature interval of 30 ~ 50 ℃, the cooling time is 0 ~ 20s, preferably at an equal time interval of 2 ~ 4s; during this period, the sample running speed range is: 0 ~ 25m / s, the acceleration range is 0 ~ 0.5m / s 2 ;

[0031] 4) Calculate the cooling rates of N cooling zones based on the experimentally recorded data, and measure the properties of the steel plate using a detection device; wherein,

[0032] According to the opening temperature T of N cooling zones recorded during the experiment n1 , cooling stop temperature T n2, cumulative cooling 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 ) / accumulated cooling time t n , n=1~N; cooling start temperature range is 500~1000℃, cooling stop temperature is 100~800℃, cooling rate range is 0~1000℃ / s;

[0033] The performance Xact of the steel plate is measured by the detection device. If Xact is within the positive and negative tolerance range allowed by the target performance Xtar, it is considered qualified, that is, ΔX1≤(Xact-Xtar)≤ΔX2; ΔX1:

[0034] Negative tolerance, ΔX2: Positive tolerance, the target performance of the steel plate and the positive and negative tolerance range are determined by user needs;

[0035] 5) Determination of optimal cooling process parameters

[0036] Select the cooling rate, start temperature, stop temperature and stop time combination of N cooling zones with qualified performance, and determine the optimal cooling rate, start temperature, stop temperature and stop time of the N cooling zones that meet the maximum process window of product production based on the production line layout and process system;

[0037] The preferred starting temperature of the first cooling zone is 800-950°C, and the cooling time between cooling zones is 4-12s;

[0038] 6) The corresponding relationship between the cooling rate and flow rate of N cooling zones determined by multi-path cooling of a sample of a certain steel grade and thickness specification is converted into the production line flow rate according to the flow density consistency principle. The flow rate range is 0-300m 3 / h;

[0039] 7) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%;

[0040] 8) Convert the flow rate of N cooling zones of the production line, calculate the opening of N cooling zones corresponding to the flow rate according to the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m 3 / h, flow control valve opening range 0% ~ 100%.

[0041] 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 site under the premise that the cooling process is consistent with the production line; 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.

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

[0043] Preferably, the trolley is driven by a motor or a traction drive.

[0044] 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.

[0045] Preferably, the sample is heated by an offline heating method or an online heating method; 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 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: 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 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, electrodes are used to clamp both sides of the sample, and the sample is directly heated online as a resistor through a large current; or, induction heating is used.

[0047] Preferably, the sample is cooled by water cooling or air cooling.

[0048] Beneficial effects of the present invention:

[0049] The present invention adopts a circular runway combined with a trolley method to realize an infinitely long cooling zone at any workpiece speed. According to the optimal cooling rate, flow rate, water ratio and production line cooling spray box layout determined by experiments, the corresponding flow rate is converted into the production line flow rate according to the flow density consistency principle, and the optimal spray box flow parameter is obtained. The flow rate of the production line cooling spray box is calibrated, and the opening corresponding to the flow rate is calculated according to the calibration curve of each cooling spray box, and the post-rolling cooling of the corresponding hot plate is controlled.

[0050] Since the cooling control method of the present invention 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 product development speed, improve process control accuracy, and reduce production line trial production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the cooling experimental device of the cooling control method of the present invention. DETAILED DESCRIPTION

[0052] See also Figure 1 The present invention provides a cooling control method for a hot plate after rolling with an adjustable flow rate cooling spray box, which comprises the following steps:

[0053] 1) A circular track 1 is combined with a trolley 2, and the trolley 2 carries the sample 100 through the sample carrier 3 to perform circular motion. The circular track 1 is an elliptical track comprising two parallel straight segments and two semicircular segments. At least one cooling spray box 4 for cooling the upper surface and / or lower surface of the sample is arranged along the straight segment track to form two straight cooling zones; each cooling spray box 4 comprises an upper and lower cooling spray box; the carrier 3 for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample 100 are unobstructed, and the jet ejected by the cooling spray box 4 is directly sprayed onto the sample 100; the sample is heated to a set temperature by a heating device 5 arranged across the circular track 1 or on the trolley 2, during which the temperature of the sample 100 is measured by a temperature measuring device 61 arranged on the trolley 2; the temperature measuring device 61 transmits data to a temperature measuring host 62 by wireless or wired means, and the temperature measuring host 62 is connected to a controller PLC;

[0054] 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 spray box, 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 production line working conditions, and the sample temperature and cooling rate are monitored and obtained in real time; wherein,

[0055] Sample running speed: 0~25m / s, acceleration: 0~0.5m / s2 ;

[0056] The flow rate adjustment range of each cooling spray box is 0~300m 3 / h, preferably, 10 to 50 m 3 / h and other flow rate intervals are set to increase or decrease to conduct cooling experiments;

[0057] The cooling temperature is 700-1000°C. Preferably, the cooling experiment is performed by increasing or decreasing the temperature at intervals of 40-60°C.

[0058] The cooling stop temperature is from room temperature to 800°C. Preferably, the experiment is conducted by increasing or decreasing the temperature by 30-50°C.

[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) Test the performance and microstructure of the samples;

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

[0062] 5) The flow rate corresponding to the optimal cooling rate obtained in the experiment is converted into the production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h;

[0063] 6) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%;

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

[0065] Preferably, in step 2), based on the start cooling temperature T1, stop cooling temperature T2 and cumulative cooling time t recorded during the experimental process, the cooling rate CR of the steel plate is calculated as follows: (start cooling temperature T1 - stop cooling temperature T2) / cumulative cooling time t, where the cumulative cooling time t is in seconds; the cooling rate range is 0 to 1000°C / s.

[0066] Preferably, in step 3), the performance Xact of the steel plate is measured by a detection device. Xact is considered qualified if it is within the positive and negative tolerance range allowed by the target performance Xtar, that is, ΔX1≤(Xact-Xtar)≤ΔX2, wherein ΔX1: negative tolerance, ΔX2: positive tolerance, and the target performance and positive and negative tolerance range of the steel plate are determined by user needs.

[0067] Preferably, in step 4), the experimental results under different combinations of cooling rate, start cooling temperature and stop cooling temperature are counted, and the combination that meets the product performance is selected for comprehensive comparison. The optimal cooling rate, start cooling temperature and stop cooling temperature that meet the maximum process window of product production are determined according to the production line layout and process system; the preferred start cooling temperature is 800-950°C, and the preferred stop cooling temperature is 550°C-750°C.

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

[0069] 1) A circular track 1 is combined with a trolley 2, and the trolley 2 carries the sample 100 through the sample carrier 3 to perform circular motion. The circular track 1 is an elliptical track comprising two parallel straight segments and two semicircular segments. At least one cooling spray box 4 for cooling the upper surface and / or lower surface of the sample is arranged along the straight segment track to form two straight cooling zones; each cooling spray box 4 comprises an upper and lower cooling spray box; the carrier 3 for fixing the sample is hollow in the middle, and the upper and lower surfaces of the sample 100 are unobstructed, and the jet ejected by the cooling spray box 4 is directly sprayed onto the sample 100; the sample is heated to a set temperature by a heating device 5 arranged across the circular track 1 or on the trolley 2, during which the temperature of the sample 100 is measured by a temperature measuring device 61 arranged on the trolley 2; the temperature measuring device 61 transmits data to a temperature measuring host 62 by wireless or wired means, and the temperature measuring host 62 is connected to a controller PLC;

[0070] 2) The driving trolley drives the sample to reach the specified process speed, maintains a constant speed or accelerates at a certain acceleration, and passes through a theoretically infinite cooling zone in a moving state to ensure that the sample is cooled from the start-cooling temperature to the target temperature under conditions basically consistent with the on-site working conditions. The cooling process temperature is detected in real time, the cooling process time is accumulated in real time, and the cooling stop time is precisely controlled;

[0071] 3) For a sample of a certain steel grade and thickness specification, a cooling combination experiment with different flow rates, cooling stop temperatures and cooling stop times in N cooling zones was conducted to determine the cooling rate and steel plate properties; the flow rate range was 0 to 300 m 3 / h, preferably at equal flow intervals of 10 to 50 m 3 / h, the cooling temperature range is 500 ~ 1000 ℃, preferably at an equal temperature interval of 40 ~ 60 ℃, the cooling temperature range is 100 ~ 800 ℃, preferably at an equal temperature interval of 30 ~ 50 ℃, the cooling time is 0 ~ 20s, preferably at an equal time interval of 2 ~ 4s; during this period, the sample running speed range is: 0 ~ 25m / s, the acceleration range is 0 ~ 0.5m / s 2 ;

[0072] 4) Calculate the cooling rates of N cooling zones based on the experimentally recorded data, and measure the properties of the steel plate using a detection device; wherein,

[0073] According to the opening temperature T of N cooling zones recorded during the experiment n1 , cooling stop temperature T n2 , cumulative cooling 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 ) / accumulated cooling time t n , n=1~N; cooling start temperature range is 500~1000℃, cooling stop temperature is 100~800℃, cooling rate range is 0~1000℃ / s;

[0074] The performance Xact of the steel plate is measured by the detection device. If Xact is within the positive and negative tolerance range allowed by the target performance Xtar, it is considered qualified, that is, ΔX1≤(Xact-Xtar)≤ΔX2; ΔX1:

[0075] Negative tolerance, ΔX2: Positive tolerance, the target performance of the steel plate and the positive and negative tolerance range are determined by user needs;

[0076] 5) Determination of optimal cooling process parameters

[0077] Select the cooling rate, start temperature, stop temperature, and stop time combinations of N cooling zones with qualified performance. Determine the optimal cooling rate, start temperature, stop temperature, and stop time for each zone to meet the maximum process window for product production based on the production line layout and process system. The preferred start temperature for the first cooling zone is 800-950°C, and the stop time between cooling zones is 4-12 seconds.

[0078] 6) The corresponding relationship between the cooling rate and flow rate of N cooling zones determined by multi-path cooling of a sample of a certain steel grade and thickness specification is converted into the production line flow rate according to the flow density consistency principle. The flow rate range is 0-300m 3 / h;

[0079] 7) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%;

[0080] 8) Convert the flow rate of N cooling zones of the production line, calculate the opening of N cooling zones corresponding to the flow rate according to the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m 3 / h, flow control valve opening range 0% ~ 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 site under the premise that the cooling process is consistent with the production line; 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.

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

[0083] Preferably, the trolley is driven by a motor or a traction drive.

[0084] 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.

[0085] Preferably, the sample is heated by an offline heating method or an online heating method; 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 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: 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 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, electrodes are used to clamp both sides of the sample, and the sample is directly heated online as a resistor through a large current; or, induction heating is used.

[0087] Preferably, the sample is cooled by water cooling or air cooling.

[0088] Example 1

[0089] The conventional cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling is based on the corresponding relationship between cooling rate and flow rate determined by experiment. 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 then the flow rate is converted into the opening degree of the regulating valve for cooling control. Specifically, it includes:

[0090] 1) Cooling spray box layout of the experimental device and experimental results

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

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

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

[0094] Experimental device single upper spray box flow rate = 108m 3 / h*0.5 / 2=27m 3 / h;

[0095] Experimental device single lower spray box flow rate = 108m 3 / h*0.5 / 2=27m 3 / h;

[0096] According to the experimental determination of the conventional cooling process parameters of a certain type of steel with a thickness of 4.5mm: the starting cooling temperature is 850℃, the final cooling temperature is 600℃ and the cooling rate is 32℃ / s as the production line process parameters. The flow rate of a single spray box of the cooling experimental device is 18m 3 / h.

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

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

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

[0100] The spacing between the post-rolling cooling spray boxes of a certain production line is the same as that of the spray boxes of the experimental device. According to the principle of consistent flow density, it can be converted according to the length of the spray box.

[0101] Production line post-rolling cooling spray box single upper spray box flow rate = 18m 3 / h*2 / 0.5=72m 3 / h;

[0102] Production line post-rolling cooling spray box single lower spray box flow rate = 18m 3 / h*2 / 0.5=72m 3 / h;

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

[0104] 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 The opening value of the flow rate / h is subjected to conventional linear interpolation:

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

[0106] The flow valve of the production line is set and the cooling is controlled according to this opening value.

[0107] Example 2

[0108] A multi-path cooling control method with adjustable flow rate for the cooling spray box after hot plate rolling is based on the experimentally determined correspondence between cooling rate and flow rate. The flow rate corresponding to the optimal cooling rate of different multi-path cooling zones obtained in the experiment is converted into production line flow rate according to the flow density consistency principle. The flow rate is then converted into the opening degree of the regulating valve in different multi-path cooling zones for cooling control. Specifically, it includes:

[0109] 1) Cooling spray box layout of the experimental device and experimental results

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

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

[0112] The cooling spray box of the experimental device is 0.5m long;

[0113] Experimental device single upper spray box flow rate = 200m 3 / h*0.5 / 2=50m 3 / h;

[0114] Experimental device single lower spray box flow rate = 240m 3 / h*0.5 / 2=60m 3 / h;

[0115] Conventional cooling process parameters for a certain type of steel with a thickness of 4.5 mm determined by experiment:

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

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

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

[0119] The cooling spray box of the experimental device is 0.5m long;

[0120] The spacing between the post-rolling cooling spray boxes of a certain production line is the same as that of the experimental device. According to the principle of consistent flow density, the length of the spray box can be converted:

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

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

[0123] Phase change production line post-rolling cooling spray box single upper spray box flow rate = 25m 3 / h*2 / 0.5=100m 3 / h;

[0124] Phase change production line post-rolling cooling spray box single lower spray box flow rate = 30m 3 / h*2 / 0.5=120m 3 / h;

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

[0126] After calibrating the flow control valve of the production line, we get:

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

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

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

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

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

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

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

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

[0135] The flow valve of the production line is set and the cooling is controlled according to this opening value.

Claims

1. A cooling control method with adjustable flow rate of a cooling spray box for 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. Each cooling spray box includes an upper and lower cooling spray box. 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 spray box, 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 production line working conditions, and the sample temperature and cooling rate are monitored and obtained in real time; wherein, Sample running speed: 0~25m / s, acceleration: 0~0.5m / s 2 ; The flow rate adjustment range of each cooling spray box is 0~300m 3 / h, preferably, 10 to 50 m 3 / h and other flow rate intervals are set to increase or decrease to conduct cooling experiments; The cooling temperature is 700-1000°C. Preferably, the cooling experiment is performed by increasing or decreasing the temperature at intervals of 40-60°C. The cooling stop temperature is from room temperature to 800°C. Preferably, the experiment is conducted by increasing or decreasing the temperature by 30-50°C. If more than two cooling spray boxes are set, the spacing between the cooling spray boxes should be consistent with the production line design; 3) Conduct performance and microstructure tests on the samples; 4) Repeat steps 2) to 3) and select cooling control parameters that ensure that the performance and structure meet the requirements based on the measured data; 5) The flow rate corresponding to the optimal cooling rate obtained in the experiment is converted into the production line flow rate according to the flow density consistency principle, and the flow rate range is 0~300m 3 / h; 6) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%; 7) Convert it into the flow rate of the production line, calculate the opening corresponding to the flow rate according to the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m 3 / h, opening range 0%~100%.

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

3. The cooling control method with adjustable flow rate of the hot plate post-rolling cooling spray box according to claim 1, characterized in that: Step 3) The performance Xact of the steel plate is measured by a detection device. Xact is considered qualified if it is within the positive and negative tolerance range allowed by the target performance Xtar, that is, ΔX1≤(Xact-Xtar)≤ΔX2, where ΔX1: negative tolerance, ΔX2: positive tolerance, and the target performance and positive and negative tolerance range of the steel plate are determined by user needs.

4. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling as claimed in claim 1, characterized in that: In step 4), the experimental results under different combinations of cooling rate, start cooling temperature and stop cooling temperature are counted, and the combination that meets the product performance is selected for comprehensive comparison. The optimal cooling rate, start cooling temperature and stop cooling temperature that meet the maximum process window of product production are determined according to the production line layout and process system; the preferred start cooling temperature is 800-950°C, and the preferred stop cooling temperature is 550°C-750°C.

5. A cooling control method with adjustable flow rate of a cooling spray box for 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 through a carrier platform and performs circular motion. The circular track is an elliptical track comprising two parallel straight segments and semicircular arc segments at both ends. At least one cooling spray box is provided along the straight segment track to cool the upper and / or lower surfaces of the sample. The carrier platform for fixing the sample is hollowed out in the middle, leaving the upper and lower surfaces of the sample unobstructed. The jet ejected by the cooling spray box is directly sprayed onto the sample, forming two linear cooling zones. The sample is heated to a set temperature by a heating device arranged across the circular track or on the trolley. During this period, the temperature of the sample is measured by a temperature measuring device provided on the trolley. 2) The driving trolley drives the sample to reach the specified process speed, maintains a constant speed or accelerates at a certain acceleration, and passes through a theoretically infinite cooling zone in a moving state to ensure that the sample is cooled from the start-cooling temperature to the target temperature under conditions basically consistent with the on-site working conditions. The cooling process temperature is detected in real time, the cooling process time is accumulated in real time, and the cooling stop time is precisely controlled; 3) Conduct cooling combination experiments at different flow rates, cooling stop temperatures, and cooling stop times in N cooling zones for a sample of a certain steel grade and thickness specification to determine the cooling rate and steel plate properties; the flow rate range is 0 to 300 m 3 / h, preferably at equal flow intervals of 10 to 50 m 3 / h, the cooling temperature range is 500 ~ 1000 ℃, preferably at an equal temperature interval of 40 ~ 60 ℃, the cooling temperature range is 100 ~ 800 ℃, preferably at an equal temperature interval of 30 ~ 50 ℃, the cooling time is 0 ~ 20s, preferably at an equal time interval of 2 ~ 4s; during this period, the sample running speed range is: 0 ~ 25m / s, the acceleration range is 0 ~ 0.5m / s 2 ; 4) Calculate the cooling rates of N cooling zones based on the experimentally recorded data, and measure the properties of the steel plate using a detection device; wherein, According to the opening temperature T of N cooling zones recorded during the experiment n1 , cooling stop temperature T n2 , cumulative cooling 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 ) / accumulated cooling time t n , n=1~N; cooling start temperature range is 500~1000℃, cooling stop temperature is 100~800℃, cooling rate range is 0~1000℃ / s; The steel plate's performance Xact is measured by a testing device. If Xact is within the positive and negative tolerance range allowed by the target performance Xtar, it is considered qualified, that is, ΔX1≤(Xact-Xtar)≤ΔX2; ΔX1: negative tolerance, ΔX2: positive tolerance. The target performance and positive and negative tolerance range of the steel plate are determined by user needs; 5) Determination of optimal cooling process parameters Select the cooling rate, start temperature, stop temperature, and stop time combinations of N cooling zones with qualified performance. Determine the optimal cooling rate, start temperature, stop temperature, and stop time for each zone to meet the maximum process window for product production based on the production line layout and process system. The preferred start temperature for the first cooling zone is 800-950°C, and the stop time between cooling zones is 4-12 seconds. 6) The corresponding relationship between the cooling rate and flow rate of N cooling zones determined by multi-path cooling of a sample of a certain steel grade and thickness specification is converted into the production line flow rate according to the flow density consistency principle. The flow rate range is 0-300m 3 / h; 7) Flow calibration of the cooling spray boxes on the production line, measuring the corresponding relationship between the flow rate of each cooling spray box and the opening of the flow control valve to form a calibration curve; the opening range is 0% to 100%, and the opening interval is 5% to 20%; 8) Convert the flow rate of N cooling zones of the production line, calculate the opening of N cooling zones corresponding to the flow rate according to the calibration curve of each cooling spray box, and set the control; the flow rate range is 0~300m 3 / h, flow control valve opening range 0% ~ 100%.

6. The cooling control method with adjustable flow rate of the cooling spray box after hot plate rolling according to claim 1 or 5, characterized in that: In step 1), the distance between the spray box and the sample surface and the nozzle diameter can be adjusted arbitrarily. 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 site under the premise that the cooling process is consistent with the production line; 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.

7. The cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling as claimed in claim 1 or 5, characterized in that: In step 1), the spacing, flow rate and number of cooling spray boxes can be adjusted arbitrarily to ensure that the experimental cooling rate is consistent with the production line on the premise that the cooling process is consistent with the production line; the spacing between cooling spray boxes ranges from 0 to 1.5m, and the flow rate of cooling spray boxes ranges from 0 to 300m 3 / h, the number of cooling spray box nozzles ranges from 1 to 200; the length of the cooling spray box ranges from 100 to 6000 mm.

8. The cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling as claimed in claim 1 or 5, characterized in that: The trolley is driven by motor or traction.

9. The cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling as claimed in claim 1 or 5, 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.

10. The cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling as claimed in claim 1 or 5, characterized in that: The sample is heated by an offline heating method or an online heating method; 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 spray box 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.

11. The cooling control method with adjustable flow rate of a hot plate cooling spray box after rolling as claimed in claim 1 or 5, characterized in that: Heating adopts resistance heating method, that is, electrodes are clamped on both sides of the sample, and the sample is directly heated online as a resistor through a large current; or, induction heating method is adopted.

12. The cooling control method with adjustable flow rate of a cooling spray box for hot plate after rolling as claimed in claim 1 or 5, characterized in that: The sample is cooled by water or air.

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