A method and system for controlling a plate middle slab water cooling device

Abstract

The application discloses a kind of plate intermediate blank water cooling device control method and system, the method comprises: the quantity of intermediate blank to be tempered between water cooling device and finishing mill is determined;The rolled temperature of current intermediate blank rolled by roughing mill, intermediate blank thickness, air cooling waiting time of intermediate blank to be tempered adjacent to water cooling device and rolling time of intermediate blank to be tempered in finishing mill are obtained;The air cooling waiting time of intermediate blank to be tempered adjacent to water cooling device and rolling time of intermediate blank to be tempered in finishing mill are combined with the steel grade characteristics of intermediate blank to determine the air cooling waiting time and water cooling target temperature of current intermediate blank after water cooling;And the water flow and cooling roller speed of water cooling device are calculated by water cooling model;The calculated water flow and roller speed are input to the execution unit of water cooling device to set, complete the water cooling control of intermediate blank, the application can make the intermediate blank of batch rolling balanced connection, reduce the inaccuracy of artificial setting to cause process abnormal situation.

Description

Technical Field

[0001] This invention relates to the field of hot-rolled ferrous metals technology, specifically to a control method and system for a water-cooling device for intermediate billets of medium-thick plates. Background Technology

[0002] Medium and heavy plates are important steel materials, widely used in large ships, marine engineering, energy equipment, and construction machinery, playing a vital role in national economic development. In terms of process layout, domestic medium and heavy plate production lines generally adopt a two-stand arrangement consisting of a roughing mill and a finishing mill. The roughing mill mainly completes the rolling of intermediate slabs and width control, while the finishing mill completes the final shape control, focusing on thickness and plate shape control. Mechanical properties are crucial indicators for heavy plates. To ensure product performance, strict requirements are typically placed on the slab heating temperature, the roughing mill's initial rolling temperature, the finishing mill's initial rolling thickness, initial rolling temperature, and final rolling temperature. Therefore, a waiting-heating roller table of varying lengths is set up between the roughing and finishing mills. The intermediate slabs rolled by the roughing mill oscillate back and forth on the waiting-heating roller table, and the initial rolling temperature of the intermediate slabs is controlled by air cooling. Therefore, the length of the waiting-heating roller table plays a decisive role in the number of intermediate slabs to be heated and directly affects the overall rolling efficiency of the line.

[0003] With increasing market competition, medium and heavy plate manufacturers are pursuing high-efficiency production to reduce manufacturing costs; therefore, efficiency improvement is a constant goal for all companies. Consequently, some companies have begun to adopt strong cooling devices for intermediate billets, adding water cooling units between the roughing and finishing mills to achieve rapid cooling of the intermediate billets and reduce the waiting time before the finishing mill. However, currently, most water cooling devices use manual settings for flow rate and cooling roller speed. Operators set these parameters based on experience, the thickness and temperature of the intermediate billet after roughing, and the process requirements of the finishing mill's starting temperature. While this method reduces waiting time, it frequently results in insufficient or over-cooling, leading to inadequate water cooling or excessively low temperatures after water cooling, significantly impacting product performance. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, this application proposes the following technical solution:

[0005] In a first aspect, embodiments of this application provide a control method for a water-cooling device for intermediate billets of medium-thick plates, including:

[0006] The quantity of intermediate billets awaiting heating between the water-cooling unit and the finishing mill is determined;

[0007] Get the post-rolling temperature of the current intermediate billet after the roughing mill has finished rolling, the current thickness of the intermediate billet, the air cooling waiting time of the intermediate billet waiting to be heated in the adjacent water cooling unit, and the rolling time of the intermediate billet waiting to be heated in the finishing mill;

[0008] The air-cooling waiting time and target water-cooling temperature of the intermediate billet after water cooling are determined based on the air-cooling waiting time of the intermediate billet in the adjacent water-cooling unit and the rolling time of the intermediate billet in the finishing mill, combined with the steel characteristics of the current intermediate billet.

[0009] Based on the current temperature of the intermediate billet after rolling in the roughing mill, the current thickness of the intermediate billet, and the target temperature after water cooling, the water flow rate and cooling roller speed of the water cooling device are calculated using a water cooling model.

[0010] The calculated water flow rate and cooling roller speed are input into the execution unit of the water cooling device for automatic setting, thereby completing the water cooling control of the intermediate billet.

[0011] In one possible implementation, determining the number of intermediate billets awaiting heating between the water-cooling device and the finishing mill includes:

[0012] The distance between adjacent intermediate billets waiting to be heated is detected by laser rangefinders arranged in the area of ​​the roller conveyor.

[0013] The number of intermediate billets to be heated is determined based on the spacing between adjacent intermediate billets and the length of the intermediate billets.

[0014] In one possible implementation, obtaining the air-cooling waiting time of the intermediate billet awaiting temperature in a nearby water-cooling unit includes:

[0015] The rolling time of the preheated intermediate billet entering the finishing mill is determined based on historical data of the finishing mill rolling rhythm.

[0016] Add the rolling time of the previous intermediate billet to the interval time before and after rolling in the finishing mill to obtain the air cooling waiting time of the intermediate billet in the adjacent finishing mill.

[0017] The air cooling waiting time of the next slab to be heated is obtained by combining the air cooling waiting time of the slab to be heated in the adjacent finishing mill with the rolling time of the slab to be heated in the adjacent finishing mill and the interval time before and after rolling in the finishing mill.

[0018] The air-cooling waiting time for the intermediate billet awaiting temperature in the adjacent water-cooling unit is determined by a recursive method.

[0019] In one possible implementation, the formula for calculating the air-cooling waiting time of the intermediate billet awaiting temperature in the adjacent water-cooling unit is as follows:

[0020] t n空冷等待 =t n-1精轧轧制 +tn-1空冷等待 +a

[0021] Where n is the number of intermediate billets awaiting heating in the adjacent water-cooling unit, and t n空冷等待 t represents the air cooling waiting time of the intermediate billet near the water cooling unit. n-1精轧轧制 t is the rolling time of the intermediate billet before the adjacent water-cooling unit. n-1空冷等待 'a' represents the air cooling waiting time of the intermediate billet before the water cooling unit, and 'a' represents the interval before and after rolling by the finishing mill.

[0022] In one possible implementation, the formulas for calculating the water flow rate and cooling roller speed of the water-cooling device using a water-cooling model are as follows:

[0023]

[0024] Where Q is the water flow rate, m is the mass of the intermediate billet, and the mass of the intermediate billet is equal to the product of the intermediate billet thickness, intermediate billet width, intermediate billet length, and intermediate billet density, c p ΔT is the specific heat capacity, ΔT is the target water-cooling temperature, and T is the target water-cooling temperature. surface T represents the surface temperature of the intermediate billet after rolling on the roughing mill. water Where is the cooling water temperature, k is the overall heat transfer coefficient, L is the length of the cooling zone, and V is the speed of the cooling roller conveyor.

[0025] In one possible implementation, the step of automatically setting the calculated water flow rate and cooling roller speed by inputting them to the execution unit of the water cooling device to complete the water cooling control of the intermediate billet includes:

[0026] The calculated water flow rate and cooling roller speed are input into the execution unit of the water cooling device to determine the water flow rate and cooling roller speed according to the principle of maximizing cooling capacity.

[0027] If the maximum water flow rate cannot meet the target cooling temperature requirement, reduce the cooling roller speed and extend the cooling time.

[0028] or;

[0029] If the intermediate billet temperature is detected to be too low, the water flow rate is dynamically reduced or the cooling roller speed is increased.

[0030] Secondly, this application provides a control system for a water-cooling device for intermediate billets of medium and heavy plates, including: a controller and a water-cooling device and a high-temperature detection module electrically connected to the controller. The water-cooling device is disposed between the roughing mill and the finishing mill, and the high-temperature detection module is disposed on the roller table to be heated. The water-cooling device is used to cool the temperature of the intermediate billet after roughing, and the high-temperature detection module is used to detect the surface temperature of the water-cooled intermediate billet.

[0031] Compared with the prior art, the beneficial effects of this application are as follows:

[0032] This application uses the sum of the air cooling waiting time and rolling time of the intermediate billet preceding the one requiring cooling on the rolling line as a basis. Through a water-cooling model, it automatically calculates the water flow rate and cooling roller speed during the cooling process of the intermediate billet, thereby maintaining a high rolling rhythm on the rolling line. This avoids the problem of operators setting the intermediate billet cooling based on personal experience, fully utilizing the capacity of the water cooling device, and reducing process anomalies such as low finishing mill start-up temperature caused by inaccurate manual settings. This method allows for stable, batch production, resulting in significant economic and social benefits.

[0033] The control method of this application has a wide range of applications, and can be applied to both single-stand rolling mills and double-stand rolling mills. Attached Figure Description

[0034] Figure 1 A schematic flowchart illustrating a control method for a water-cooling device for intermediate billets of medium-thick plates provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the process layout and batch rolling mode for medium and heavy plates provided in the embodiments of this application.

[0036] Figure 2 The symbols are: 1-roughing mill, 2-intermediate billet being rolled by the roughing mill, 3-water cooling device, 4-first intermediate billet waiting to be heated, 5-second intermediate billet waiting to be heated, 6-third intermediate billet waiting to be heated, 7-finishing mill, 8-steel plate being rolled by the finishing mill. Detailed Implementation

[0037] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.

[0038] Figure 1 A flowchart illustrating a control method for a water-cooling device for intermediate billets of medium-thick plates, provided in an embodiment of this application, is shown below. Figure 1 The control method for a water-cooling device for intermediate billets of medium-thick plates in this embodiment includes:

[0039] S101 determines the number of intermediate billets waiting to be heated between the water cooling unit and the finishing mill.

[0040] In this embodiment, the distance between adjacent intermediate billets is detected by a laser rangefinder arranged in the area of ​​the heated roller conveyor, and the number of intermediate billets to be heated is determined based on the distance between adjacent intermediate billets and the length of the intermediate billets.

[0041] S102, obtain the post-rolling temperature of the current intermediate billet after the roughing mill has finished rolling, the current thickness of the intermediate billet, the air cooling waiting time of the intermediate billet waiting to be heated in the adjacent water cooling unit, and the rolling time of the intermediate billet waiting to be heated in the finishing mill.

[0042] In this embodiment, the rolling time of the intermediate billet to be heated is determined based on the historical data of the rolling rhythm of the finishing mill. The rolling time of the previous intermediate billet to be heated is added to the interval time before and after the finishing mill rolling to obtain the air cooling waiting time of the intermediate billet to be heated near the finishing mill. The air cooling waiting time of the next intermediate billet to be heated is obtained by combining the air cooling waiting time of the intermediate billet to be heated near the finishing mill with the rolling time of the intermediate billet to be heated near the finishing mill and the interval time before and after the finishing mill rolling. The air cooling waiting time of the intermediate billet to be heated near the water cooling device is determined by recursion.

[0043] join Figure 2 In this embodiment, there are three intermediate billets awaiting heating: the first intermediate billet 4, the second intermediate billet 5, and the third intermediate billet 6. The rolling time of the billet being rolled by the finishing mill is determined based on historical rolling rhythm data. The air-cooling waiting time of the third intermediate billet 6 is obtained by adding the rolling time and the interval time between the two steel plates. The interval time between the two steel plates is the positioning time from when the upper intermediate billet is thrown to when the lower intermediate billet arrives at the finishing mill 7. Since the throwing speed of the finishing mill 7 is constant, the positioning position before the finishing mill is constant, and the distance the intermediate billet is transported to the finishing mill is constant, the interval time can be considered a constant. Therefore, the air-cooling waiting times of the first intermediate billet 4, the second intermediate billet 5, and the third intermediate billet 6 are as follows:

[0044] t 6空冷等待 =t 8精轧轧制 +a

[0045] t 5空冷等待 =t 6精轧轧制 +t 6空冷等待 +a

[0046] t 4空冷等待 =t 5精轧轧制 +t 5空冷等待 +a.

[0047] S103, based on the air cooling waiting time of the intermediate billet waiting to be heated in the adjacent water cooling unit and the rolling time of the intermediate billet waiting to be heated in the finishing mill, combined with the steel characteristics of the current intermediate billet, determine the air cooling waiting time and water cooling target temperature of the current intermediate billet after water cooling.

[0048] S104, based on the current temperature of the intermediate billet after rolling in the roughing mill, the current thickness of the intermediate billet, and the target temperature after water cooling, the water flow rate and cooling roller speed of the water cooling device are calculated using the water cooling model.

[0049] In this embodiment, the calculation formulas for the water flow rate and cooling roller speed of the water cooling device using the water cooling model are as follows:

[0050]

[0051] Where Q is the water flow rate, m is the mass of the intermediate billet, and the mass of the intermediate billet is equal to the product of the intermediate billet thickness, intermediate billet width, intermediate billet length, and intermediate billet density, c p ΔT is the specific heat capacity, ΔT is the target water-cooling temperature, and T is the target water-cooling temperature. surface T represents the surface temperature of the intermediate billet after rolling on the roughing mill. water Where is the cooling water temperature, k is the overall heat transfer coefficient, L is the length of the cooling zone, and V is the speed of the cooling roller conveyor.

[0052] S105 inputs the calculated water flow rate and cooling roller speed into the execution unit of the water cooling device for automatic setting, thus completing the water cooling control of the intermediate billet.

[0053] In this embodiment, the calculated water flow rate and cooling roller speed are input into the execution unit of the water cooling device to determine the water flow rate and cooling roller speed according to the principle of maximizing cooling capacity. Due to the diversity of medium and heavy plate rolling processes, the thickness of the intermediate billet and the starting temperature of the finishing rolling of the steel plates before and after rolling will vary significantly. At the same time, the design flow rate of the intermediate water cooling device is fixed. Therefore, affected by the rolling process, if the maximum flow rate of the intermediate cooling device cannot meet the target temperature process requirements, the maximum flow rate of the system is used, and the roller speed is reduced to minimize the temperature after cooling and reduce the air cooling time. If the intermediate billet temperature is detected to be too low, the water flow rate is dynamically reduced or the cooling roller speed is increased.

[0054] Specifically, taking continuously cast slabs of Q355D and S460M steel grades as examples, the raw material is a continuously cast slab with dimensions of 250*2450*L0mm. The steel grade used is Q355D, and the finished product dimensions are set as (50-55)*(2575-2645)*L1mm. The rolling process uses a two-stand rolling mill for roughing and finishing. The slab heating time is 300-340 minutes, the tapping temperature is 1180-1200℃, and the slab is in the soaking section for about 32 minutes. Intermediate billets numbered 79030-79070 were rolled in batches between roughing mill 1 and finishing mill 7. Billet 79030 was awaiting rolling at the finishing mill, followed by billets 79040, 79050, 79060, and 79070. During this process, an automatic water cooling system was used to adjust the water flow and speed of the intermediate billets. Calculations were performed to set the water cooling flow rate and speed for each billet. After water cooling, each billet required air cooling and rolling. The rolling times for the 79030 finishing mill are as follows: 88 seconds for the rolling mill and 125 seconds for the air-cooled oscillation waiting time. Based on the data for 79030, the system calculates the finishing mill rolling time for 79040 to be 148 seconds and the air-cooled oscillation waiting time to be 295 seconds. The finishing mill rolling times for 79050, 79060, and 79070 are subsequently determined to be 158 seconds, 178 seconds, and 218 seconds, respectively, with air-cooled oscillation waiting times of 550 seconds, 705 seconds, and 890 seconds, respectively. Using these parameters, all multiple upper and lower manifolds of the cooling device are put into operation, with a flow rate of 92 m³ / s for each upper manifold. 3 / h, 120m³ / h for each downstream manifold 3 / h, the roller conveyor speed is set to 0.52m / s.

[0055] The raw material is continuously cast slab, with slab dimensions of 300*1800*L0mm. The steel grade used is S460M. The finished product dimensions are 45*2860*L1mm. The rolling process uses a two-stand rolling mill for roughing and finishing. The slab heating time is set to 280-300min, the tapping temperature is 1180-1200℃, and the slab is in the soaking zone for about 34min.

[0056] Intermediate billets numbered 88020-88050 formed a batch rolling pattern between roughing mill 1 and finishing mill 7. 88020 was waiting to be rolled in front of the finishing mill, followed by 88030, 88040, and 88050 in sequence. During this process, an automatic water cooling device was used to adjust the water flow and speed. Based on calculations using this method, the water cooling flow rate and speed for each intermediate billet were set. After water cooling, the required air cooling and rolling times for each intermediate billet were as follows: 88020's finishing mill rolling time was 81 seconds, and the air cooling and warming time was 125 seconds. Based on the data for 88020, the finishing mill rolling time for 88030 was calculated to be 153 seconds, and the warming time was 235 seconds. The finishing mill rolling times for 88040 and 88050 were calculated to be 161 seconds and 193 seconds, respectively, and the air cooling and warming times were 380 seconds and 725 seconds, respectively. Based on the above parameters, all the upper and lower manifolds of the cooling device were put into operation, with a flow rate of 91m³ / h for each upper manifold. 3 / h, 120m³ / h for each downstream manifold 3 The roller conveyor speed is set to 0.43 m / s per hour. This automatic control method fully utilizes the capabilities of the water-cooling equipment, ensuring even connection of intermediate billets in batch rolling and achieving efficient rolling.

[0057] Corresponding to the control method for a water-cooling device for intermediate billets of medium and heavy plates provided in the above embodiments, this application also provides an embodiment of a control system for a water-cooling device for intermediate billets of medium and heavy plates.

[0058] The water-cooling control system for the intermediate slab of medium-thick plate according to an embodiment of this application includes: a controller, a water-cooling device 3 electrically connected to the controller, and a high-temperature detection module. The water-cooling device 3 is located between the roughing mill 1 and the finishing mill 7. The high-temperature detection module is located on the waiting-to-warm roller table. The controller is used to collect relevant parameters of the intermediate slab 2 being rolled in the roughing mill, the first waiting-to-warm intermediate slab 4, the second waiting-to-warm intermediate slab 5, and the third waiting-to-warm intermediate slab 6, and the steel plate 8 being rolled in the finishing mill. Specifically, it collects the temperature and thickness of the intermediate slab 2 after the roughing mill rolling is completed, the remaining rolling time of the steel plate 8 being rolled in the finishing mill, the air-cooling waiting time and rolling time of the waiting-to-warm intermediate slab, and the interval time between the two steel plates before and after the finishing mill rolling. The water-cooling device 3 is used to cool the temperature of the intermediate slab after roughing, and the high-temperature detection module is used to detect the surface temperature of the water-cooled intermediate slab. If the temperature calculated by the model deviates significantly from the detected temperature, the detected temperature is used for correction to improve the accuracy of the model calculation.

[0059] In this embodiment, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, or the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0060] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method of controlling a plate bloom water cooling device, characterized by, include: The quantity of intermediate billets awaiting heating between the water-cooling unit and the finishing mill is determined, including: The distance between adjacent intermediate billets waiting to be heated is detected by laser rangefinders arranged in the area of ​​the roller conveyor. The number of intermediate billets to be heated is determined based on the spacing between adjacent intermediate billets and the length of the intermediate billets. Get the post-rolling temperature of the current intermediate billet after the roughing mill has finished rolling, the current thickness of the intermediate billet, the air cooling waiting time of the intermediate billet waiting to be heated in the adjacent water cooling unit, and the rolling time of the intermediate billet waiting to be heated in the finishing mill; The waiting time for the air cooling of the intermediate billet awaiting temperature in the adjacent water-cooling unit is obtained, including: The rolling time of the preheated intermediate billet entering the finishing mill is determined based on historical data of the finishing mill rolling rhythm. Add the rolling time of the previous intermediate billet to the interval time before and after rolling in the finishing mill to obtain the air cooling waiting time of the intermediate billet in the adjacent finishing mill. The air cooling waiting time of the next slab to be heated is obtained by combining the air cooling waiting time of the slab to be heated in the adjacent finishing mill with the rolling time of the slab to be heated in the adjacent finishing mill and the interval time before and after rolling in the finishing mill. The air-cooling waiting time for the intermediate billet awaiting temperature in the adjacent water-cooling unit is determined by a recursive method. The formula for calculating the air cooling waiting time of the intermediate billet awaiting temperature in the adjacent water-cooling unit is as follows: in, This represents the number of intermediate billets awaiting heating in the adjacent water-cooling unit. This refers to the air cooling waiting time for the intermediate billet to reach the temperature near the water cooling unit. The rolling time of the intermediate billet before the adjacent water-cooling unit. This refers to the air cooling waiting time for the intermediate billet that is awaiting temperature before the adjacent water cooling unit. This refers to the time interval before and after rolling in the finishing mill. The air-cooling waiting time and target water-cooling temperature of the intermediate billet after water cooling are determined based on the air-cooling waiting time of the intermediate billet in the adjacent water-cooling unit and the rolling time of the intermediate billet in the finishing mill, combined with the steel characteristics of the current intermediate billet. Based on the current temperature of the intermediate billet after rolling in the roughing mill, the current thickness of the intermediate billet, and the target temperature after water cooling, the water flow rate and cooling roller speed of the water cooling device are calculated using a water cooling model. The calculated water flow rate and cooling roller speed are input into the execution unit of the water cooling device for automatic setting, thereby completing the water cooling control of the intermediate billet.

2. The control method for the water-cooling device of the intermediate billet of medium-thick plate according to claim 1, characterized in that, The formulas for calculating the water flow rate and cooling roller speed of the water-cooling device using the water-cooling model are as follows: in, For water flow rate, The mass of the intermediate billet is equal to the product of its thickness, width, length, and density. For specific heat capacity, The temperature difference that needs to be reduced for intermediate billets This refers to the surface temperature of the intermediate billet after it has been rolled on the roughing mill. For cooling water temperature, To consider the overall heat transfer coefficient, The length of the cooling zone. This refers to the speed of the cooling roller conveyor.

3. The control method for the water-cooling device of the intermediate billet of medium-thick plate according to claim 1, characterized in that, The step of automatically setting the calculated water flow rate and cooling roller speed by inputting them into the execution unit of the water cooling device to complete the water cooling control of the intermediate billet includes: The calculated water flow rate and cooling roller speed are input into the execution unit of the water cooling device to determine the water flow rate and cooling roller speed according to the principle of maximizing cooling capacity. If the maximum water flow rate cannot meet the target cooling temperature requirement, reduce the cooling roller speed and extend the cooling time. or; If the intermediate billet temperature is detected to be too low, the water flow rate is dynamically reduced or the cooling roller speed is increased.

4. A control system for a water-cooling device for intermediate billets of medium-thick plates, employing the control method described in any one of claims 1-3, characterized in that, include: The controller, a water-cooling device, and a high-temperature detection module electrically connected to the controller are provided. The water-cooling device is located between the roughing mill and the finishing mill, and the high-temperature detection module is located on the roller table to be heated. The water-cooling device is used to cool the temperature of the intermediate billet after roughing, and the high-temperature detection module is used to detect the surface temperature of the water-cooled intermediate billet.

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