Control Method of Ultra-Fast Cooling System in Hot Strip Mill Production Line

Abstract

A control method for an ultra-fast cooling system in a hot strip mill production line, belonging to the technical field of metal rolling, includes: the communication system collects the data of the rolled piece and transmits it to the process automation system, and after setting and calculation, the result is given to the basic automation system; when the rolled piece reaches the second rolling mill, the basic automation system sends the relevant flow rate and pressure mode data to the pumping station system, and the pumping station determines the frequency increase according to the water pump situation; when the strip head reaches the third rolling mill and is in the dry head control mode, the basic automation system calculates the compensation distance of the headers of the front and rear ultra-fast cooling systems; when the head reaches the fifth rolling mill, the initial opening degree of the bypass regulating valve is set and the pressure closed-loop control is started; when the head reaches the pyrometer at the exit of the finishing mill, the dynamic setting calculation is started and the pressure compensation of the front ultra-fast cooling system is processed; afterwards, according to the different positions of the strip head in the front and rear ultra-fast cooling systems, the bypass regulating valve is adjusted and the closed-loop control is switched; after the strip tail leaves each cooling area, the water pump frequency is reduced and the headers of the front and rear ultra-fast cooling systems are closed in sequence.

Description

Technical Field

[0001] This application belongs to the technical field of metal rolling, and specifically relates to a control method for an ultra-fast cooling system in a hot strip mill production line. Background Art

[0002] In the field of hot strip mill production technology, ultra-fast cooling technology is a key technology for regulating the microstructure and properties of hot-rolled strip steel.

[0003] In practical applications, to ensure the accuracy of strip steel temperature control during the entire cooling process, when the strip steel enters the cooling area of the ultra-fast cooling system, it is necessary to ensure that the flow rate and pressure of the ultra-fast cooling system are in a stable state. However, due to special temperature control requirements at the head of the strip steel, such as the implementation of the dry head process. During the control process of the dry head process, it is easy to cause large fluctuations in the pressure of the ultra-fast cooling system. Such pressure fluctuations not only disrupt the originally set stable operating state of the system, but also lead to large deviations in the head temperature control, making it difficult for the cooling process to be accurately executed according to the predetermined process parameters, greatly affecting the stability and consistency of product quality.

[0004] Especially in the complex process layout with front and rear ultra-fast cooling systems in the production line layout, the coordinated operation between the front and rear ultra-fast cooling systems and the stable control of their respective pressures have become a huge challenge. Due to the different positions and functions of the front and rear systems in the strip steel cooling process, they are interrelated and interact with each other. How to effectively coordinate the pressure changes of the front and rear ultra-fast cooling systems during the special process treatment of the strip steel head and throughout the entire cooling process, achieve stable and reliable pressure control, and thus ensure the smooth and successful progress of the strip steel cooling process has become a key problem that urgently needs to be solved in the industrial application of the ultra-fast cooling system in current hot strip mill production. Summary of the Invention

[0005] In view of this, this application provides a control method for an ultra-fast cooling system in a hot strip mill production line. The main purpose is to achieve the stability of the flow rate and pressure of the ultra-fast cooling system, thereby ensuring the accuracy of strip steel temperature control.

[0006] To achieve the above object, this application mainly provides the following technical solutions:

[0007] This application provides a control method for an ultra-fast cooling system in a hot strip mill production line. The ultra-fast cooling system includes an ultra-fast cooling device, a basic automation system, a process automation system, and a communication system. The control method includes the following steps:

[0008] Step 1: After the finishing mill setting calculation is completed, the communication system collects the product data information of the rolled piece, the finishing mill setting data, and the real-time data of the rolling line, and transmits them to the process automation system. The process automation system completes the setting calculation of the strip cooling process based on the received data and transmits the calculation results to the basic automation system;

[0009] Step 2: When the rolled piece arrives at the second rolling mill, the basic automation system transmits the single-header flow rate, total flow rate, and pressure mode in the setting calculation results to the pump station system;

[0010] Step 3: Determine the number of available water pumps. The pump station system determines the pump frequency according to the pump number-pressure-flow rate table and starts the frequency increase operation according to the frequency curve;

[0011] Step 4: When the strip head arrives at the third rolling mill and the strip head is in the dry head control mode, the basic automation system calculates the compensation distance of each header of the front and rear ultra-fast cooling systems according to the dry head length, strip speed, response time of the header opening and closing valve, and cooling mode of the ultra-fast cooling system issued by the process automation system;

[0012] Step 5: When the strip head arrives at the fifth rolling mill, set the initial opening degree of the bypass regulating valve of the front and rear ultra-fast cooling systems and turn on the pressure closed-loop control of the front ultra-fast cooling;

[0013] Step 6: When the strip head reaches the finishing mill exit pyrometer:

[0014] (1) Start the dynamic setting calculation of the strip cooling process, and dynamically adjust the opening state of the headers in the cooling zone according to the measured starting cooling temperature, strip speed, and target temperature of each section;

[0015] (2) Cancel the input of the pressure closed-loop calculation of the front ultra-fast cooling system. According to the total set water volume of the front ultra-fast cooling system issued by the process automation system and the actual water volume feedback by the pump station system, calculate the compensation value of the bypass regulating valve of the front ultra-fast cooling system for the strip head pressure compensation, and calculate the compensation slope of the bypass regulating valve of the front ultra-fast cooling system according to the speed of the last finishing mill stand and the length of the cooling area of the front ultra-fast cooling system;

[0016] Step 7: When the strip head is in the cooling area of the front ultra-fast cooling system, the bypass regulating valve of the front ultra-fast cooling system is adjusted according to the calculated compensation slope; after the strip head leaves the cooling area of the front ultra-fast cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the front ultra-fast cooling system are put into operation;

[0017] Step 8: When the strip head reaches the fine-tuning section of laminar cooling, the basic automation system calculates the compensation value of the bypass regulating valve of the post-ultra-fast cooling system for the strip head pressure compensation based on the total water volume set by the process automation system for the post-ultra-fast cooling system and the actual water volume feedback from the pumping station system, and calculates the compensation slope of the bypass regulating valve of the post-ultra-fast cooling system according to the speed of the last finishing stand and the length of the cooling area of the post-ultra-fast cooling system; when the strip head reaches the first header of the post-ultra-fast cooling system, the input of the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-fast cooling system is cancelled;

[0018] Step 9: When the strip head is in the cooling area of the post-ultra-fast cooling system, the bypass regulating valve of the post-ultra-fast cooling system is adjusted according to the calculated compensation slope; when the strip head leaves the cooling area of the post-ultra-fast cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre- and post-ultra-fast cooling systems are input;

[0019] Step 10: After the strip tail leaves the cooling area of the pre-ultra-fast cooling system, the pumping station system receives the water consumption of the post-ultra-fast cooling system sent by the basic automation system, determines the pump frequency, and starts to reduce the frequency according to the frequency reduction curve. After reducing to the first specific frequency, the headers of the pre-ultra-fast cooling system are closed in sequence;

[0020] Step 11: After the strip tail leaves the cooling area of the post-ultra-fast cooling system, the pump frequency is reduced to the basic frequency. After reducing to the second specific frequency, the headers of the post-ultra-fast cooling system are closed in sequence.

[0021] Optionally, the ultra-fast cooling device includes multiple groups of pre-ultra-fast cooling and multiple groups of post-ultra-fast cooling. The pre-ultra-fast cooling is located between the finishing mill and the laminar cooling, and the post-ultra-fast cooling is located between the laminar finishing header and the coiler.

[0022] Optionally, in Step 4, the compensation distance of each header conforms to the formula:

[0023] ;

[0024] In the formula, is the target dry head length, m; is the threading speed of the strip, m / s; is the valve response time, s; is the number of headers opened in the ultra-fast cooling system; is the serial number of the opened header.

[0025] Optionally, in Step 6, the compensation value of the bypass regulating valve of the pre-ultra-fast cooling system conforms to the formula:

[0026] ;

[0027] In the formula, The total set water volume of the pre - ultra - fast cooling system issued by the process automation system, m³ / h; The number of bypass regulating valves of the pre - ultra - fast cooling system; The number of bypass regulating valves of the post - ultra - fast cooling system; The opening degree of the bypass regulating valve of the pre - ultra - fast cooling system set initially; The opening degree of the bypass regulating valve of the post - ultra - fast cooling system set initially; The water volume feedback after the pump station system frequency increases; The maximum drainage volume of the sewage pipeline.

[0028] Optionally, in the sixth step, the compensation slope of the bypass regulating valve of the pre - ultra - fast cooling system conforms to the formula:

[0029] ;

[0030] In the formula, is the compensation value of the bypass regulating valve of the pre - ultra - fast cooling system, is the threading speed of the strip, m / s; is the length of the cooling area of the pre - ultra - fast cooling system, m.

[0031] Optionally, in the eighth step, the compensation value of the bypass regulating valve of the post - ultra - fast cooling system conforms to the formula:

[0032] ;

[0033] In the formula, is the total set water volume of the post - ultra - fast cooling system issued by the process automation system, m³ / h; is the number of bypass regulating valves of the pre - ultra - fast cooling system; is the number of bypass regulating valves of the post - ultra - fast cooling system; is the opening degree of the bypass regulating valve of the pre - ultra - fast cooling system when the system pressure stabilizes within the set pressure range after the pressure closed - loop calculation is put into operation; is the opening degree of the bypass regulating valve of the post - ultra - fast cooling system set initially; is the actual water volume of the pre - ultra - fast cooling system, m³ / h; is the water volume feedback after the pump station system frequency increases; is the maximum drainage volume of the sewage pipeline.

[0034] Optionally, in the eighth step, the compensation slope of the bypass regulating valve of the post - ultra - fast cooling system conforms to the formula:

[0035] ;

[0036] In the formula, is the compensation value of the bypass regulating valve of the post-ultra-fast cooling system is the threading speed of the strip, m / s; is the length of the cooling zone of the post-ultra-fast cooling system, m.

[0037] By means of the above technical solutions, the present application has at least the following beneficial effects:

[0038] In the embodiment of the present application, the control method of the ultra-fast cooling system in the hot strip rolling production line can estimate and compensate for possible pressure changes in advance by calculating the compensation distance of each header of the front and post-ultra-fast cooling systems, reducing the impact of the dry head process on the pressure stability of the entire ultra-fast cooling system, and enabling the ultra-fast cooling system to maintain a relatively stable pressure environment when the strip head enters the cooling zone. At the same time, the front and post-ultra-fast cooling pressure closed-loop control is turned on and off in a timely manner. When the strip head is in different cooling zones, such as the cooling zones of the front and post-ultra-fast cooling systems, by precisely adjusting the bypass regulating valve and reasonably switching the pressure closed-loop control, the pressure fluctuations caused by factors such as strip speed changes, header opening and closing, and the connection of different cooling zones are effectively balanced, ensuring the stability of the pressure during the entire cooling process, avoiding the impact on equipment such as pipelines and valves of the ultra-fast cooling device caused by unstable pressure, extending the service life of the equipment, and at the same time ensuring the stable progress of the cooling process, improving the product quality and production efficiency.

[0039] Furthermore, starting from the end of the finishing mill setting calculation, through the collaborative data acquisition and calculation transfer of the communication system, process automation system, and basic automation system, the set values of the flow rate of a single header and the total flow rate are accurately determined based on various data of the rolled piece and transmitted to the pumping station system. The pumping station system determines the appropriate pump frequency based on the accurate pump number-pressure-flow rate table and performs a frequency increase operation, providing a basic guarantee for stable flow rate, enabling the entire cooling process to accurately allocate the flow rate according to the set requirements, and avoiding cooling non-uniformity and product quality problems caused by flow rate fluctuations. At the same time, at different stages of the strip head and tail, by reasonably controlling the bypass regulating valve of the front and post-ultra-fast cooling systems, such as calculating the compensation value and compensation slope based on the difference between the set total water volume and the actual water volume, and dynamically adjusting the bypass regulating valve, the flow rate changes caused by various factors, such as special processes at the head and cooling zone switching at the tail, are effectively compensated, ensuring that the flow rate is always in a relatively stable state during the entire strip cooling process, thereby guaranteeing the consistency of the cooling effect and the stability of the product quality. Description of the Drawings

[0040] Figure 1 is the flowchart of the control method of an optional embodiment of the present application;

[0041] Figure 2 is the pressure control curve of the traditional ultra-fast cooling system;

[0042] Figure 3 For application Figure 1 The pressure control curve diagram of the ultra-fast cooling system of the control method shown;

[0043] Figure 4 For application Figure 1 The temperature control curve diagram of the ultra-fast cooling system of the control method shown. Detailed implementation manners

[0044] Hereinafter, exemplary embodiments of the present application will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0045] See Figure 1 As shown, an embodiment of the present application provides a control method for an ultra-fast cooling system in a hot strip rolling production line. The ultra-fast cooling system includes an ultra-fast cooling device, a basic automation system, a process automation system, and a communication system.

[0046] Among them, the ultra-fast cooling device can be composed of ultra-fast cooling headers and is used for cooling the strip steel. The basic automation system is used to receive instructions from the upper-level system, such as the process automation system, and convert these instructions into specific device operation signals to control the operation of the ultra-fast cooling device and related auxiliary devices, such as water pumps, valves, etc. The process automation system is built with mathematical models and algorithms for performing setting calculations during the strip steel cooling process. For example, according to the material of the strip steel and the performance requirements of the final product, the target temperatures to be achieved at different cooling stages are calculated, as well as the cooling parameters such as the flow rate of the cooling medium and the opening state of the headers required to achieve these target temperatures. Then, these calculation results are sent to the basic automation system to guide its specific operation control of devices such as the cooling device. The communication system is used to connect each component of the ultra-fast cooling system so that data can be continuously exchanged between the components. For example, the calculation results of the process automation system are transmitted to the basic automation system so that the basic automation system can perform corresponding operations.

[0047] Specifically, in a hot strip rolling production line, the ultra-rapid cooling device has multiple groups of pre-ultra-rapid cooling and multiple groups of post-ultra-rapid cooling. The pre-ultra-rapid cooling is located between the finishing mill and the laminar cooling. The finishing mill is a key device for rolling the final shape of the strip, making the strip still in a relatively high temperature state after leaving the finishing mill. At this time, the pre-ultra-rapid cooling quickly intervenes and rapidly reduces the strip temperature by means of ultra-rapid cooling, thereby refining the grain structure. The post-ultra-rapid cooling is located between the laminar cooling header and the coiler. The post-ultra-rapid cooling is used for the second-stage cooling of the strip after pre-ultra-rapid cooling. The post-ultra-rapid cooling can quickly cool the strip to the target coiling temperature by precisely controlling the cooling rate. With the coordinated cooperation of the pre- and post-ultra-rapid cooling, it is possible to comprehensively and precisely control the temperature change of the strip in the cooling section from after finishing to before coiling in the hot strip rolling production line, thereby achieving the strengthening and toughening of the steel product.

[0048] The control method includes the following steps:

[0049] Step 1: After the finishing mill setting calculation is completed, the communication system collects the product data information, finishing mill setting data, and real-time rolling line data of the rolled piece and transmits them to the process automation system. The process automation system completes the setting calculation of the strip cooling process based on the received data and transmits the calculation results to the basic automation system.

[0050] In this embodiment, after the rolling line update calculation is completed, it means that in the hot strip rolling production line, the calculation of some basic parameters related to the rolled piece is completed. At this time, the communication system starts to play a role, and the communication system will collect data from multiple aspects. The product data information of the rolled piece includes the material information and specification information of the strip. The specification information can include thickness information, width information, etc. These data determine the basic requirements for the subsequent cooling process because different materials and specifications of strips require different cooling strategies to achieve ideal performance. The finishing mill setting data covers various setting parameters of the finishing mill, such as the target final rolling temperature, rolling speed, etc. of the finishing mill. These parameters are closely related to the state of the strip after finishing and will affect the starting conditions of the cooling process. The real-time rolling line data reflects the actual operating state of the current rolling line, such as the actual temperature of the strip, the running speed of the strip and other dynamic information. After collecting all these data, the communication system transmits them to the process automation system. The process automation system uses the temperature model, heat transfer model, and setting model according to the received data to complete the setting calculation of the strip cooling process. This calculation process will determine key parameters such as the water volume distribution required for cooling and the cooling temperature setting in different regions. Finally, these calculation results are transmitted to the basic automation system to provide a basis for subsequent actual control operations.

[0051] Step 2: When the rolled piece arrives at the second rolling mill, the basic automation system transmits the single header flow rate, total flow rate, and pressure mode in the setting calculation results to the pumping station system.

[0052] In this embodiment, when the rolled piece arrives at the second rolling mill, the final finish rolling setting calculation is completed for the rolled piece. The process automation system receives the updated calculated data, correspondingly updates the setting calculation for the cooling process, and sends the calculation result to the basic automation system. The basic automation system extracts the key information such as the flow rate of each header, the total flow rate, and the pressure mode from the calculation result and transmits it to the pumping station system. The flow rate of each header determines the flow rate of the cooling medium, such as water, in each cooling header. The total flow rate is the overall water flow rate requirement of the entire ultra-fast cooling system, and the pressure mode specifies the pressure state that the system should maintain. The pumping station system needs this information to prepare to provide an appropriate supply of the cooling medium. For example, if the flow rate of each header is set to 100 m³ / h, the total flow rate is 4000 m³ / h, and the pressure mode is the high-pressure mode, the basic automation control system sends this information to the pumping station system so that the pumping station system can prepare to provide the cooling medium according to such flow rate and pressure requirements.

[0053] Step 3: Determine the number of available water pumps. The pumping station system determines the water pump frequency based on the water pump number - pressure - flow rate table and starts the frequency increase operation according to the frequency curve.

[0054] In this embodiment, first, the number of available water pumps needs to be determined because the number of water pumps in the pumping station system may change due to reasons such as the operation mode and equipment maintenance. After determining the number of available water pumps, the water pump frequency is determined based on the water pump number - pressure - flow rate table. This table is obtained through calibration and continuous optimization during the actual production process. It clarifies the frequency at which the water pump should operate to achieve specific pressure and flow rates under different combinations of the number of water pumps. After determining the frequency, the frequency increase operation is started according to the frequency curve. The frequency curve is usually designed according to the performance characteristics of the equipment and the process requirements. The frequency curve specifies the variation law of the frequency with time during the process of the water pump starting up to reaching the target frequency. Through this frequency increase operation, the water pump gradually increases its rotational speed, thereby steadily increasing the water pressure and water volume to meet the initial requirements of the cooling system. For example, if it is determined that there are five available water pumps, by looking up the table, it is found that to achieve the set flow rate and pressure, the water pump frequency needs to be increased from 20 Hz to 35 Hz, then the frequency of the water pump is increased according to the frequency increase curve.

[0055] Step 4: When the head of the strip arrives at the third rolling mill and the head of the strip is in the dry head control mode, the basic automation system calculates the compensation distance of each header of the front and rear ultra-fast cooling systems according to the dry head length, strip speed, response time of the header opening and closing valve, and the cooling mode of the ultra-fast cooling system issued by the process automation system.

[0056] In this embodiment, when the strip head arrives at the third rolling mill and is in the dry head control mode, since the situation of the strip head is special when it first enters the cooling area and is different from the cooling requirements of the subsequent main part of the strip. The basic automation system calculates the compensation distance of each header of the front and rear ultra-rapid cooling systems according to parameters such as the dry head length, strip speed, response time of the header opening and closing valve, and cooling mode of the ultra-rapid cooling system issued by the process automation system. The dry head length determines the range of the strip head that needs special treatment. The strip speed affects the speed of heat exchange, cooling time, and control accuracy of the dry head. The response time of the header opening and closing valve is related to the timeliness and accuracy of cooling control, while the cooling mode stipulates the overall cooling strategy framework. By comprehensively considering these factors to calculate the compensation distance, the purpose is to adjust the opening state or flow distribution of the headers in advance to compensate for the uneven cooling or pressure fluctuations that may be caused by the special situation of the dry head, ensuring that when the strip head enters the formal cooling area, the entire ultra-rapid cooling system can smoothly transition to the normal cooling state and avoid drastic fluctuations in system pressure and flow due to dry head problems. For example, the dry head length is 3m, the strip speed is 5m / s, the response time of the header opening and closing valve is 0.1s, and the cooling mode is segmented cooling. Through calculation, it can be determined how long each header needs to start cooling after the strip head passes by, and this distance is the compensation distance.

[0057] Specifically, the compensation distance of each header conforms to the formula:

[0058] ;

[0059] In the formula, is the target dry head length, in m; is the threading speed of the strip, in m / s; is the valve response time, in s; is the number of headers opened in the ultra-rapid cooling system; is the serial number of the opened header.

[0060] Step Five: When the strip head arrives at the fifth rolling mill, set the initial opening degree of the bypass regulating valves of the front and rear ultra-rapid cooling systems, and turn on the front ultra-rapid cooling pressure closed-loop control.

[0061] In this embodiment, when the head of the strip reaches the fifth rolling mill, it is closer to entering the cooling area, and further preparation needs to be made for the upcoming cooling process. Set the initial opening degrees of the bypass regulating valves of the front and rear ultra-fast cooling systems. The bypass regulating valves can adjust the flow distribution of the cooling medium and the pressure of the ultra-fast cooling system. By setting appropriate initial opening degrees, a preliminary stable pressure and flow base state can be established before the cooling starts. At the same time, start the pressure closed-loop control of the front ultra-fast cooling. The pressure closed-loop control is an automatic control method. It monitors the pressure value in the system in real time through a sensor, compares it with the set target pressure, and automatically adjusts relevant equipment such as the pump speed and valve opening according to the difference, so that the system pressure is always maintained near the set value, so as to quickly respond and stabilize the pressure when the strip enters the cooling area. For example, set the initial opening degree of the bypass regulating valve to 30%, so that part of the cooling medium passes through the bypass pipe and part enters the cooling header. After the pressure closed-loop control is put into operation, if the actual pressure is higher than the set pressure, the system will automatically adjust equipment such as valves to reduce the pressure.

[0062] Step Six: When the head of the strip reaches the finishing mill exit pyrometer:

[0063] (1) Start the dynamic setting calculation of the strip cooling process, and dynamically adjust the opening state of the headers in the cooling area according to the measured starting cooling temperature, strip speed and target temperatures of each section;

[0064] (2) Cancel the input of the pressure closed-loop calculation of the front ultra-fast cooling system. Calculate the compensation value of the bypass regulating valve of the front ultra-fast cooling system for the strip head pressure compensation based on the total set water volume of the front ultra-fast cooling system issued by the process automation system and the actual water volume feedback by the pumping station system, and calculate the compensation slope of the bypass regulating valve of the front ultra-fast cooling system according to the speed of the last finishing mill stand and the length of the cooling area of the front ultra-fast cooling system.

[0065] In this embodiment, when the head of the strip reaches the high-temperature meter at the exit of the finishing mill, this is a key starting point of the cooling process. The dynamic setting calculation of the strip cooling process is started because in actual production, although there is a previous setting calculation, due to various actual factors, such as minor deviations of equipment, differences between the actual temperature of the rolled piece and the expected temperature, etc., it is necessary to dynamically adjust the opening state of the headers in the cooling zone according to the measured starting cooling temperature, i.e., the actual temperature measured at the exit of the finishing mill for the strip, the strip speed, and the target temperature of each section. For example, if the measured starting cooling temperature is high, it may be necessary to increase the number of opened headers or increase the header flow rate to accelerate the cooling speed; if the strip speed becomes faster, it may be necessary to adjust the header layout and flow distribution accordingly to ensure that the strip can reach the target temperature of each section at the appropriate position; cancel the input of the pressure closed-loop calculation of the pre-ultra-fast cooling system because when the head of the strip just enters the cooling zone, due to the special thermal state of the head and the connection problem with the subsequent strip, the previously activated pressure closed-loop control may cause unstable regulation due to factors such as the instantaneous thermal shock of the head. At this time, according to the total set water volume of the pre-ultra-fast cooling system issued by the process automation system and the actual water volume feedback by the pumping station system, calculate the compensation value of the bypass regulating valve of the pre-ultra-fast cooling system for the pressure compensation of the strip head. If there is a deviation between the set total water volume and the actual water volume, compensation needs to be carried out through the bypass regulating valve, and according to the speed of the last finishing mill stand and the length of the cooling zone of the pre-ultra-fast cooling system, calculate the compensation slope of the bypass regulating valve of the pre-ultra-fast cooling system. The compensation slope determines the regulation rate of the bypass regulating valve during the process of the strip head passing through the cooling zone of the pre-ultra-fast cooling system to achieve stable compensation and control of the pressure.

[0066] Specifically, the compensation value of the bypass regulating valve of the pre-ultra-fast cooling system conforms to the formula:

[0067] ;

[0068] In the formula, is the total set water volume of the pre-ultra-fast cooling system issued by the process automation system, m³ / h; is the number of bypass regulating valves of the pre-ultra-fast cooling system; is the number of bypass regulating valves of the post-ultra-fast cooling system; is the opening degree of the bypass regulating valve of the pre-ultra-fast cooling system set initially; is the opening degree of the bypass regulating valve of the post-ultra-fast cooling system set initially; is the water volume feedback after the pumping station system increases the frequency; is the maximum drainage volume of the sewage pipeline.

[0069] The compensation slope of the bypass regulating valve of the pre-ultra-fast cooling system conforms to the formula:

[0070] ;

[0071] In the formula, is the compensation value of the bypass regulating valve of the pre-ultra-rapid cooling system, is the threading speed of the strip steel, m / s; is the length of the cooling zone of the pre-ultra-rapid cooling system, m.

[0072] Step 7: When the head of the strip steel is in the cooling zone of the pre-ultra-rapid cooling system, the bypass regulating valve of the pre-ultra-rapid cooling system is adjusted according to the calculated compensation slope; after the head of the strip steel leaves the cooling zone of the pre-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-rapid cooling system are put into operation.

[0073] In this embodiment, when the head of the strip steel is in the cooling zone of the pre-ultra-rapid cooling system, the bypass regulating valve of the pre-ultra-rapid cooling system is adjusted according to the previously calculated compensation slope. In this way, the flow distribution of the cooling medium is gradually adjusted to compensate for the pressure fluctuations caused by factors such as the change in the thermal state of the head of the strip steel and the change in the header flow, so that the pressure can remain relatively stable when the head of the strip steel passes through the cooling zone of the pre-ultra-rapid cooling system. After the head of the strip steel leaves the cooling zone of the pre-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-rapid cooling system are put into operation. Because at this time, the head of the strip steel has passed through the initial special treatment stage and entered the relatively stable main body cooling process, the pressure closed-loop calculation and header flow closed-loop calculation can accurately adjust the system parameters according to the difference between the set value and the actual monitored value, ensuring that the entire pre-ultra-rapid cooling system maintains stable pressure and flow during the main body cooling process of the strip steel.

[0074] Step 8: When the head of the strip steel reaches the fine-tuning section of the laminar cooling, the basic automation system calculates the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system for compensating the pressure of the head of the strip steel according to the total set water volume of the post-ultra-rapid cooling system issued by the process automation system and the actual water volume feedback by the pumping station system, and calculates the compensation slope of the bypass regulating valve of the post-ultra-rapid cooling system according to the speed of the last finishing stand and the length of the cooling zone of the post-ultra-rapid cooling system; when the head of the strip steel reaches the first header of the post-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-rapid cooling system are cancelled.

[0075] In this embodiment, when the strip head reaches the fine-tuning section of laminar cooling, similar to the previous principle, the basic automation system calculates the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system for the strip head pressure compensation based on the total water volume set by the process automation system for the post-ultra-rapid cooling system and the actual water volume feedback by the pumping station system. Since the thermal state of the strip head when it enters the post-ultra-rapid cooling system and the cumulative effect of the previous cooling process will affect the pressure balance of the post-system, compensation needs to be carried out through the bypass regulating valve. Then, according to the speed of the last finishing stand and the length of the cooling area of the post-ultra-rapid cooling system, the compensation slope of the bypass regulating valve of the post-ultra-rapid cooling system is calculated. When the strip head reaches the first header of the post-ultra-rapid cooling system, the input of the pressure closed-loop calculation and the header flow closed-loop calculation of the pre-ultra-rapid cooling system is cancelled. This is because at this time, the main focus is on the cooling and pressure control of the strip head by the post-ultra-rapid cooling system, avoiding the interference of the closed-loop control of the pre-system on the post-system, so that the post-ultra-rapid cooling system can independently and accurately cool and regulate the pressure of the strip head.

[0076] Specifically, the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system conforms to the formula:

[0077] ;

[0078] In the formula, is the total water volume set by the process automation system for the post-ultra-rapid cooling system, m³ / h; is the number of bypass regulating valves of the pre-ultra-rapid cooling system; is the number of bypass regulating valves of the post-ultra-rapid cooling system; is the opening degree of the bypass regulating valve of the pre-ultra-rapid cooling system when the system pressure stabilizes within the set pressure range after the pressure closed-loop calculation is put into operation; is the initial set opening degree of the bypass regulating valve of the post-ultra-rapid cooling system; is the actual water volume of the pre-ultra-rapid cooling system, m³ / h; is the water volume feedback after the pumping station system increases the frequency; is the maximum drainage volume of the sewage pipeline.

[0079] The compensation slope of the bypass regulating valve of the post-ultra-rapid cooling system conforms to the formula:

[0080] ;

[0081] In the formula, is the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system, is the threading speed of the strip, m / s; is the length of the cooling area of the post-ultra-rapid cooling system, m.

[0082] Step Nine: When the strip head is in the cooling area of the post-ultra-rapid cooling system, the bypass regulating valve of the post-ultra-rapid cooling system is adjusted according to the calculated compensation slope; when the strip head leaves the cooling area of the post-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre- and post-ultra-rapid cooling systems are put into operation.

[0083] In this embodiment, when the strip head is in the cooling area of the post-ultra-rapid cooling system, the bypass regulating valve of the post-ultra-rapid cooling system is adjusted according to the calculated compensation slope to cope with the heat exchange changes and flow demand changes of the strip head in the post-ultra-rapid cooling system and stabilize the system pressure. When the strip head leaves the cooling area of the post-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre- and post-ultra-rapid cooling systems are put into operation. At this time, the special cooling stage of the strip head ends, and the entire strip enters a comprehensive stable cooling stage. Both the pre- and post-ultra-rapid cooling systems require precise closed-loop control to maintain stable pressure and flow, ensuring uniform cooling effect of the entire strip and meeting the product quality requirements.

[0084] Step Ten: After the strip tail leaves the cooling area of the pre-ultra-rapid cooling system, the pumping station system receives the water consumption of the post-ultra-rapid cooling system sent by the basic automation system, determines the pump frequency, and starts to reduce the frequency according to the frequency reduction curve. After reducing to the first specific frequency, the headers of the pre-ultra-rapid cooling system are closed in sequence.

[0085] In this embodiment, after the strip tail leaves the cooling area of the pre-ultra-rapid cooling system, the pumping station system receives the water consumption information of the post-ultra-rapid cooling system sent by the basic automation system. Since the cooling demand in the cooling area of the pre-ultra-rapid cooling system decreases after the strip tail leaves the pre-area, the operating parameters of the pumping station need to be adjusted according to the water consumption in the cooling area of the post-ultra-rapid cooling system. Determine the pump frequency and start to reduce the frequency according to the frequency reduction curve. The frequency reduction curve is designed according to the equipment characteristics and process requirements to ensure that the pump speed is smoothly reduced and avoid pressure fluctuations or other equipment failures caused by sudden speed reduction. After reducing to the first specific frequency, the headers of the pre-ultra-rapid cooling system are closed in sequence, gradually reducing the supply of cooling medium in the pre-area, so that the entire system resources are reasonably allocated to the cooling process in the post-area. For example, if the water consumption of the post-ultra-rapid cooling system is 7000 m³ / h, it is determined through calculation that the pump frequency needs to be reduced from 40 Hz to 20 Hz, and the frequency is reduced according to the frequency reduction curve. When the frequency drops to 20 Hz, the headers of the pre-ultra-rapid cooling system are closed in sequence.

[0086] Step Eleven: After the strip tail leaves the cooling area of the post-ultra-rapid cooling system, the pump frequency is reduced to the base frequency. After reducing to the second specific frequency, the headers of the post-ultra-rapid cooling system are closed in sequence.

[0087] In this embodiment, when the tail of the strip steel leaves the cooling area of the post-positioned ultra-fast cooling system, the water pump frequency drops to the base frequency, which means that the entire cooling process is approaching the end, and the system gradually returns to the initial standby state. After dropping to the second specific frequency, the headers of the post-positioned ultra-fast cooling system are closed in sequence, completely stopping the supply of the cooling medium, completing the cooling process of the entire strip steel, and at the same time ensuring that the pressure drops smoothly during the stop process of the system, and the equipment safely and orderly ends the operating state, preparing for the next strip steel rolling and cooling.

[0088] Specifically, the second specific frequency is less than the first specific frequency. For example, the base frequency is 20Hz, the first specific frequency is 35Hz, and the second specific frequency is 25Hz. When the tail of the strip steel leaves the cooling area of the post-positioned ultra-fast cooling system, the pumping station system starts the frequency reduction operation. As the tail of the strip steel leaves, the system's demand for the cooling water volume decreases sharply, and the water pump frequency gradually drops from the current operating frequency, such as 45Hz, according to the frequency reduction curve determined by the water pump number-frequency-flow curve. When the frequency drops to the first specific frequency of 35Hz, the basic automation system sends a closing instruction to the header control module of the pre-positioned ultra-fast cooling system, and then the headers of the pre-positioned ultra-fast cooling system are closed in sequence starting from the header closest to the tail of the strip steel according to the predetermined closing order. This process is to gradually stop the cooling function of the pre-positioned ultra-fast cooling system, avoiding the pressure shock caused by sudden closing and the instability inside the cooling system. After the closing of the headers of the pre-positioned ultra-fast cooling system is completed, when the tail of the strip steel enters the post-positioned ultra-fast cooling system, the water pump frequency continues to drop. When it drops to the second specific frequency of 25Hz, the headers of the post-positioned ultra-fast cooling system also start to be closed in sequence, ensuring that the entire closing process proceeds smoothly without damaging the equipment.

[0089] In this embodiment, by calculating the compensation distances of each header of the front and rear ultra-rapid cooling systems, it is possible to estimate and compensate for possible pressure changes in advance, reduce the impact of the dry head process on the pressure stability of the entire ultra-rapid cooling system, and enable the ultra-rapid cooling system to maintain a relatively stable pressure environment when the strip head enters the cooling area. At the same time, the front ultra-rapid cooling pressure closed-loop control is timely turned on and off. When the strip head is in different cooling areas, through the precise adjustment of the bypass regulating valve and the reasonable switching of the pressure closed-loop control, the pressure fluctuations caused by factors such as strip speed changes, header opening and closing, and the connection of different cooling areas are effectively balanced, ensuring the stability of the pressure during the entire cooling process, avoiding additional impacts and wear on equipment such as the pipes and valves of the ultra-rapid cooling device due to unstable pressure, extending the service life of the equipment, and at the same time ensuring the stable progress of the cooling process, improving product quality and production efficiency. Further, starting from the end of the rolling line update calculation, through the collaborative data acquisition and calculation transfer of the communication system, process automation system, and basic automation system, the set values of the flow rate of each single header and the total flow rate are accurately determined based on various data of the rolled piece and transmitted to the pumping station system. The pumping station system determines the appropriate pump frequency based on the accurate pump number-pressure-flow rate table and performs a frequency increase operation, providing a basic guarantee for stable flow rate, enabling the entire cooling process to accurately allocate the flow rate according to the set requirements, and avoiding cooling unevenness and product quality problems caused by flow rate fluctuations. At the same time, at different stages of the strip head and tail, through the reasonable control of the bypass regulating valves of the front and rear ultra-rapid cooling systems, such as calculating the compensation value and compensation slope based on the difference between the set total water volume and the actual water volume, and dynamically adjusting the bypass regulating valve, the flow rate changes caused by various factors, such as special processes at the head and cooling area switching at the tail, are effectively compensated, ensuring that the flow rate remains relatively stable throughout the strip cooling process, thereby ensuring the consistency of the cooling effect and the stability of product quality.

[0090] Based on the above Figure 1 The shown control method focuses on the production process of DP590 steel with a thickness of 11.1 mm. The control method of the ultra-rapid cooling system in the hot strip rolling production line adopted includes the following specific steps:

[0091] First, after the rolling line update calculation is completed, the communication system starts to receive product data information (PDI), finishing mill set data, and rolling line real-time data related to the DP590 steel grade. Subsequently, the process automation system conducts the set calculation of the strip cooling process based on the received data by using specific algorithms and models. After the calculation is completed, the process automation system timely sends the calculation results to the basic automation system, providing a key basis for subsequent cooling control operations.

[0092] When the strip head reaches the finishing mill F1 stand, the basic automation system (Level 1) receives a series of key parameters sent from the process control system (Level 2). These include the upper header flow rate of the pre-ultra-rapid cooling system set at 80 m³ / h, the lower header flow rate set at 100 m³ / h, the number of opened and closed valves determined to be 16 groups. From this, the total water volume of the pre-ultra-rapid cooling system is calculated to be 2880 m³ / h; for the post-ultra-rapid cooling system, the upper header flow rate is set at 130 m³ / h, the lower header flow rate is set at 150 m³ / h, the number of opened and closed valves is 20 groups, and the total water volume is 5600 m³ / h. At the same time, the pressure mode set value of 0.85 Mpa is received.

[0093] Meanwhile, when the strip head reaches the finishing mill F2, the basic automation system immediately sends a frequency increase signal to the pumping station system and transmits the set pressure of 0.85 Mpa and the total water volume of 10480 m³ / h (including the bypass regulation volume of 2000 m³ / h) to the pumping station system. The pumping station system, based on the pre-set correspondence between pressure, flow rate, and frequency, raises the water pump frequency to 45 Hz, thus providing a stable and appropriate water pressure and water volume basis for the subsequent cooling process.

[0094] When the strip head reaches the finishing mill F3 stand, according to parameters such as the dry head length of 5 m, the strip speed of 2.9 m / s, the response time of the opened and closed valves of 0.2 s, and the cooling mode of 2 sent by the process automation system, through the set calculation formula, the compensation distance of each header of the pre- and post-ultra-rapid cooling systems is obtained. The calculation of this compensation distance aims to anticipate and compensate in advance for the possible uneven cooling and pressure fluctuations caused by the dry head process, ensuring that the cooling system can maintain a relatively stable operating state when the strip head enters the cooling area.

[0095] When the strip head reaches the finishing mill F5 stand, the initial opening degree of the bypass regulating valve of the pre-ultra-rapid cooling system is set at 30%, and the initial opening degree of the bypass regulating valve of the post-ultra-rapid cooling system is set at 30%. Additionally, the pre-ultra-rapid cooling pressure closed-loop calculation is enabled. During the process of the calculated pressure stabilizing at 0.85 Mpa, it is determined that the opening degree of the pre-bypass regulating valve should be 45%. In this way, before the strip is about to enter the cooling area, a stable pressure environment is initially established, and the pressure is monitored and adjusted in real time through the pressure closed-loop calculation to ensure the smooth start of the cooling process.

[0096] When the strip head reaches the finishing mill exit pyrometer (FDT), the input of the pressure closed-loop calculation of the pre-ultra-rapid cooling system is suspended. At this time, according to the total set water volume of 2880 m³ / h of the pre-ultra-rapid cooling system issued by the process automation and the actual water volume of 11000 m³ / h feedback by the pump station, the compensation value of the bypass regulating valve of the pre-ultra-rapid cooling system for head pressure compensation is calculated to be 19.5%. At the same time, according to the speed of 2.9 m / s of finishing mill F7 and the length of 18.2 m of the cooling area of the pre-ultra-rapid cooling system, the compensation slope of the bypass regulating valve is calculated to be 4.88. Through the calculation and application of the compensation value and compensation slope, when the strip head enters the cooling area of the pre-ultra-rapid cooling system, the pressure changes caused by various factors can be effectively compensated, ensuring the stability of pressure during the cooling process.

[0097] After the strip head leaves the cooling area of the pre-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-rapid cooling system are input again. Thus, when the strip body enters the cooling area, the accuracy of closed-loop control can be used to ensure that the pressure and flow of the pre-ultra-rapid cooling system always maintain the set ideal state, ensuring the consistency and stability of the cooling effect.

[0098] When the strip head reaches the fine-tuning section of laminar cooling, the control system calculates the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system for head pressure compensation to be 53.2% according to the total set water volume of 5600 m³ / h of the post-ultra-rapid cooling system issued by the process automation. And according to the speed of 2.9 m / s of finishing mill F7 and the length of 9 m of the cooling area of the post-ultra-rapid cooling system, the compensation slope of the bypass regulating valve is calculated to be 11.2. When the strip head reaches the first header of the post-ultra-rapid cooling system, the input of the pressure closed-loop calculation and header flow closed-loop calculation of the pre-ultra-rapid cooling system is suspended, so as to concentrate on the precise control of the cooling process of the post-ultra-rapid cooling system and avoid mutual interference between the front and rear systems.

[0099] After the strip head leaves the cooling area of the post-ultra-rapid cooling system, the pressure closed-loop calculation and header flow closed-loop calculation of the pre- and post-ultra-rapid cooling systems are input again. Thereafter, the control system dynamically adjusts the opening states of the pre- and post-ultra-rapid cooling headers according to the requirements of the product cooling process. By real-time adjusting parameters such as the number of opened headers and the flow rate, the final cooling temperature of the strip is precisely controlled to meet the target requirements, thus ensuring that the produced DP590 steel products have excellent tissue properties.

[0100] Furthermore, Figure 2 and Figure 3 respectively show the pressure control curves of the ultra-rapid cooling system before and after adopting the control method provided by this embodiment, which are used to intuitively reflect the significant effect of this control method in stabilizing pressure. Figure 4The strip temperature control situation is presented, further proving that the present control method can effectively control the strip temperature within the target range and meet the requirements of the production process.

[0101] The above discloses only several specific implementation scenarios of the present application. However, the present application is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A control method for an ultra-fast cooling system in a hot continuous rolling production line, the ultra-fast cooling system comprising an ultra-fast cooling device, a basic automation system, a process automation system, and a communication system, characterized in that, The control method includes the following steps: Step 1: After the finish of finish rolling setting calculation, the communication system collects the product data information, finish rolling setting data and real-time rolling line data of the rolled piece, and transmits them to the process automation system. The process automation system completes the setting calculation of the strip cooling process based on the received data, and transmits the calculation result to the basic automation system; Step 2: When the rolled piece arrives at the second rolling mill, the basic automation system transmits the single header flow rate, total flow rate and pressure mode in the setting calculation result to the pumping station system; Step 3: Determine the number of available water pumps. The pumping station system determines the water pump frequency according to the water pump number-pressure-flow rate table, and starts the frequency increase operation according to the frequency curve; Step 4: When the strip head arrives at the third rolling mill and the strip head is in the dry head control mode, the basic automation system calculates the compensation distance of each header of the front and rear ultra-rapid cooling systems according to the dry head length, strip speed, response time of the header opening and closing valve and the cooling mode of the ultra-rapid cooling system issued by the process automation system; Step 5: When the strip head arrives at the fifth rolling mill, set the initial opening degree of the bypass regulating valve of the front and rear ultra-rapid cooling systems, and turn on the pressure closed-loop control of the front ultra-rapid cooling system; Step 6: When the strip head reaches the finish rolling exit pyrometer: (1) Start the dynamic setting calculation of the strip cooling process, and dynamically adjust the opening state of the headers in the cooling zone according to the measured starting cooling temperature, strip speed and target temperature of each section; (2) Cancel the input of the pressure closed-loop calculation of the front ultra-rapid cooling system. Calculate the compensation value of the bypass regulating valve of the front ultra-rapid cooling system for the strip head pressure compensation according to the set total water volume of the front ultra-rapid cooling system issued by the process automation system and the actual water volume fed back by the pumping station system, and calculate the compensation slope of the bypass regulating valve of the front ultra-rapid cooling system according to the speed of the last finishing mill stand and the length of the cooling zone of the front ultra-rapid cooling system; Step 7: When the strip head is in the cooling zone of the front ultra-rapid cooling system, the bypass regulating valve of the front ultra-rapid cooling system is adjusted according to the calculated compensation slope; after the strip head leaves the cooling zone of the front ultra-rapid cooling system, input the pressure closed-loop calculation and header flow closed-loop calculation of the front ultra-rapid cooling system; Step 8: When the strip head reaches the laminar cooling fine-tuning section, the basic automation system calculates the compensation value of the bypass regulating valve of the rear ultra-rapid cooling system for the strip head pressure compensation according to the set total water volume of the rear ultra-rapid cooling system issued by the process automation system and the actual water volume fed back by the pumping station system, and calculates the compensation slope of the bypass regulating valve of the rear ultra-rapid cooling system according to the speed of the last finishing mill stand and the length of the cooling zone of the rear ultra-rapid cooling system; when the strip head reaches the first header of the rear ultra-rapid cooling system, cancel the input of the pressure closed-loop calculation and header flow closed-loop calculation of the front ultra-rapid cooling system; Step 9: When the strip head is in the cooling zone of the rear ultra-rapid cooling system, the bypass regulating valve of the rear ultra-rapid cooling system is adjusted according to the calculated compensation slope; when the strip head leaves the cooling zone of the rear ultra-rapid cooling system, input the pressure closed-loop calculation and header flow closed-loop calculation of the front and rear ultra-rapid cooling systems; Step Ten: After the tail of the strip steel leaves the cooling area of the pre - installed ultra - fast cooling system, the pumping station system receives the water consumption of the post - installed ultra - fast cooling system sent by the basic automation system, determines the water pump frequency, and starts to reduce the frequency according to the frequency - reduction curve. After reducing to the first specific frequency, the headers of the pre - installed ultra - fast cooling system are closed in sequence; Step Eleven: After the tail of the strip steel leaves the cooling area of the post - installed ultra - fast cooling system, the water pump frequency is reduced to the basic frequency. After reducing to the second specific frequency, the headers of the post - installed ultra - fast cooling system are closed in sequence.

2. The control method of the ultra-fast cooling system in the hot continuous rolling production line according to claim 1, characterized in that, The ultra - fast cooling device includes multiple groups of pre - installed ultra - fast cooling units and multiple groups of post - installed ultra - fast cooling units. The pre - installed ultra - fast cooling units are located between the finishing mill and the laminar cooling, and the post - installed ultra - fast cooling units are located between the laminar cooling headers and the coiler.

3. The control method of the ultra-fast cooling system in the hot continuous rolling production line according to claim 1, characterized in that, In Step Four, the compensation distance of each header conforms to the formula: ； In the formula, is the target dry head length, in m; is the threading speed of the strip, in m / s; is the valve response time, in s; is the number of headers opened in the ultra-fast cooling system; is the serial number of the opened header.

4. The control method of the ultra-fast cooling system in the hot strip rolling production line according to claim 1, characterized in that In Step Six, the compensation value of the bypass regulating valve of the pre - installed ultra - fast cooling system conforms to the formula: ； In the formula, is the total set water volume of the pre - ultra - fast cooling system issued by the process automation system, m³ / h; is the number of bypass regulating valves of the pre - ultra - fast cooling system; is the number of bypass regulating valves of the post - ultra - fast cooling system; is the opening degree of the bypass regulating valve of the pre - ultra - fast cooling system set initially; is the opening degree of the bypass regulating valve of the post - ultra - fast cooling system set initially; is the water volume feedback after the pump station system increases the frequency; is the maximum drainage volume of the sewage pipeline.

5. The control method of the ultra-fast cooling system in the hot strip rolling production line according to claim 1, characterized in that, In Step Six, the compensation slope of the bypass regulating valve of the pre - installed ultra - fast cooling system conforms to the formula: ； In the formula, is the compensation value of the bypass regulating valve of the pre - front ultrafast cooling system, is the threading speed of the strip steel, m / s; is the cooling zone length of the pre - front ultrafast cooling system, m.

6. The control method of the ultra-fast cooling system in the hot strip rolling production line according to claim 1, characterized in that, In Step Eight, the compensation value of the bypass regulating valve of the post - installed ultra - fast cooling system conforms to the formula: ； In the formula, is the total set water volume of the post-ultra-rapid cooling system issued by the process automation system, m³ / h; is the number of bypass regulating valves of the pre-ultra-rapid cooling system; is the number of bypass regulating valves of the post-ultra-rapid cooling system; is the opening degree of the bypass regulating valve of the pre-ultra-rapid cooling system when the system pressure stabilizes within the set pressure range after the pressure closed-loop calculation is put into operation; is the initial set opening degree of the bypass regulating valve of the post-ultra-rapid cooling system; is the actual water volume of the pre-ultra-rapid cooling system, m³ / h; is the water volume feedback after the pump station system increases the frequency; is the maximum drainage volume of the sewage pipeline.

7. The control method of the ultra-fast cooling system in the hot continuous rolling production line according to claim 1, characterized in that, In Step Eight, the compensation slope of the bypass regulating valve of the post - installed ultra - fast cooling system conforms to the formula: ； In the formula, is the compensation value of the bypass regulating valve of the post-ultra-rapid cooling system, is the threading speed of the strip steel, m / s; is the cooling zone length of the post-ultra-rapid cooling system, m.

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