Uniform cooling device for hot-rolled low-carbon strip steel

Abstract

The utility model provides a uniform cooling device for hot-rolled low-carbon strip steel. The uniform cooling device comprises a laminar cooling section, an aerial fog cooling section and a water replenishing cooling section which are sequentially arranged between a finishing mill group and a coiling machine, the laminar cooling section comprises a first-stage laminar cooling mechanism, a second-stage laminar cooling mechanism and a third-stage laminar cooling mechanism which are arranged in sequence; and an infrared imager for monitoring the transverse temperature of the strip steel in real time is arranged at the upstream of each stage of laminar cooling mechanism. Each stage of laminar cooling mechanism comprises four rows of cooling headers arranged side by side, one end of each cooling header is connected with a cooling water supply pipe, the other end of each cooling header is connected with two columns of gooseneck pipes, the gooseneck pipes are evenly distributed in the width direction of the low-carbon strip steel, the adjacent columns of gooseneck pipes are arranged in a staggered mode, and each gooseneck pipe is provided with an electric valve with the adjustable opening degree.

Description

Technical Field

[0001] The utility model relates to a strip steel cooling device, in particular to a hot-rolled low-carbon strip steel uniform cooling device. Background Art

[0002] The coiling temperature of hot-rolled strip is one of the important process parameters that affect the performance of finished strip. The final rolling temperature of hot-rolled strip of different specifications is generally 800℃~900℃. In order to obtain good structural properties of the strip, the coiling temperature of the strip must generally be controlled at 550~700℃. The purpose of laminar cooling is to control the temperature of the strip through the cooling process, so that the strip temperature is cooled from the final rolling temperature at the finish rolling outlet to the required coiling temperature, so as to obtain a finished steel coil with excellent structural properties.

[0003] The running time of the strip on the rolling line roller is about 10s. If you want to reduce the temperature of the strip by 100-350℃ in such a short time before the finishing rolling end stand to the coiler, it is far from enough to rely solely on the temperature drop caused by natural cooling such as the heat radiation of the strip on the roller and the heat conduction of the strip to the roller. Therefore, laminar cooling devices are arranged above and below the conveyor roller, and several laminar headers are installed on the upper and lower sides of the output roller of the finishing mill to form a cooling belt with a length of tens of meters to more than 100 meters to cool the upper surface of the plate and strip. The entire cooling belt is divided into several cooling sections, and each cooling section is controlled by a valve to control the spray pipe. The cooling speed of the plate and strip is controlled by controlling the water flow and the number of cooling sections opened. A large amount of cooling water contacts the surface of the strip, forming a physical form similar to a film, and the strip transfers the temperature to the cooling water to cool down.

[0004] The metallographic structure of low carbon steel is ferrite + pearlite, and the transformation temperature of pearlite is around 680-700℃. However, the traditional laminar cooling water header is installed on one side of the laminar header, and the gooseneck tubes installed on the laminar header have the same aperture and spacing, which leads to high water pressure on the side close to the water header and low water pressure on the side far from the water header. As a result, the lateral water flow rate of the gooseneck tube is different, the lateral temperature of the strip is uneven, and it is strip-shaped. The local temperature difference can reach 50-80℃, resulting in different pearlite transformation temperatures and growth rates, thus causing mixed crystal phenomenon, resulting in large differences in the stamping performance of low carbon steel, affecting the stability of mechanical properties, and becoming a major problem that needs to be solved urgently.

[0005] At the same time, due to the transverse temperature distribution of the temperature drop at the edge of the hot-rolled strip, the strip is subjected to tensile stress in the middle and compressive stress at the edge, that is, the stress caused by the temperature drop during the cooling process causes the strip shape to develop in the direction of edge waves. The analysis also found that: under the same equipment conditions or transverse temperature distribution of the strip, the higher the cooling rate, the higher the internal stress of the strip; the wider the strip width, the more difficult it is to control the transverse temperature difference, and the more serious the uneven temperature distribution.

[0006] During the cooling process of the strip, the strain mainly comes from temperature and phase change. Temperature is the driving force for phase change, and the phase change process will release heat to affect the temperature of the strip. The uneven strain of each part of the strip will cause stress in the strip. When the local compressive stress exceeds the critical buckling stress, the strip will have plate defects such as wave shape. According to the wave shape judgment theory, the wave defect of the strip is the external manifestation of internal stress: if the stress state of the strip is compressive stress at the edge and tensile stress in the middle, the strip shape is edge wave or has an edge wave trend; if it is tensile stress at the edge and compressive stress in the middle, the strip shape is middle wave or has a middle wave trend. Regardless of whether it is the middle wave shape or the edge wave shape, it has an impact on the processes such as pipe making and cold rolling that cannot be ignored, resulting in a reduction in the yield rate, and even downgrading or scrapping. Utility Model Content

[0007] The utility model provides a hot-rolled low-carbon steel strip uniform cooling device to overcome the drawbacks of the prior art.

[0008] The technical solution adopted by the utility model to solve its technical problems is:

[0009] A uniform cooling device for hot-rolled low-carbon steel strip comprises a laminar cooling section, an air mist cooling section and a water supply cooling section which are sequentially arranged between a finishing mill and a coiler; the laminar cooling section comprises a first-stage laminar cooling mechanism, a second-stage laminar cooling mechanism and a third-stage laminar cooling mechanism which are sequentially arranged, and an infrared imager for real-time monitoring of the transverse temperature of the steel strip is arranged upstream of each stage of the laminar cooling mechanism.

[0010] A further improvement of the utility model is that the first-stage laminar cooling mechanism, the second-stage laminar cooling mechanism and the third-stage laminar cooling mechanism have the same structure and all include four rows of cooling manifolds arranged side by side, one end of the cooling manifold is connected to the cooling water supply pipe, and the other end is connected to two rows of goosenecks, the goosenecks are evenly distributed along the width direction of the low-carbon strip steel, and the goosenecks in adjacent rows are staggered.

[0011] A further improvement of the utility model is that the number of the gooseneck tubes is 25 to 30, and the diameter of the gooseneck tubes is 20 mm to 23 mm.

[0012] A further improvement of the utility model is that an electric valve with adjustable opening is arranged on each of the gooseneck pipes.

[0013] A further improvement of the utility model is that the detection points of each infrared imager are the same as the number of gooseneck tubes of the downstream laminar cooling mechanism, and the number and position of the detection points correspond one-to-one to the arrangement position of the gooseneck tubes.

[0014] A further improvement of the utility model is that five groups of aerosol cooling mechanisms are arranged in the aerosol cooling section, each group of aerosol cooling mechanisms is provided with a plurality of aerosol nozzles, the aerosol nozzles are arranged in an array, and their width covers the lateral width of the strip; the aerosol nozzles are connected to the cooling water supply pipe through an aerosol collecting pipe, and a high-pressure pump is installed on the aerosol collecting pipe.

[0015] A further improvement of the utility model is that the length of the aerosol nozzle is 28-30 mm, and the inner diameter is 0.5-0.8 mm.

[0016] A further improvement of the utility model is that the array form of the aerosol nozzles is 3 rows×20, and the 20 aerosol nozzles are evenly arranged along the transverse direction of the steel strip.

[0017] A further improvement of the utility model is that the 10 aerosol nozzles located in the middle are all in an open state, the 5 aerosol nozzles located at both ends are in an open state in alternate rows, and the aerosol nozzles in adjacent rows are staggered.

[0018] A further improvement of the utility model is that a first infrared imager is arranged between the outlet end of the finishing mill and the first-stage laminar cooling mechanism, a second infrared imager is arranged downstream of the first-stage laminar cooling mechanism, a third infrared imager is arranged downstream of the second-stage laminar cooling mechanism, a fourth infrared imager is arranged downstream of the third-stage laminar cooling mechanism, a fifth infrared imager is arranged downstream of the mist cooling section, and a sixth infrared imager is arranged downstream of the water replenishment cooling section.

[0019] The beneficial effects of the utility model are:

[0020] The utility model discloses a uniform cooling device for hot-rolled low-carbon steel strip. By sequentially arranging a laminar cooling section, an aerosol cooling section and a water supply cooling section, the originally disordered cooling process is improved into a precisely controllable step-type cooling process, so that the cooling and phase change processes become controllable; at the same time, the gooseneck flow rate of the three-stage laminar cooling mechanism arranged in the laminar cooling section can be adjusted with the temperature of the steel strip, which can eliminate the temperature difference between the middle and edge of the steel strip to the maximum extent, gradually reduce the lateral temperature difference of the steel strip and finally achieve uniformity, effectively improve the uniformity of the steel strip organizational structure, and avoid the generation of steel strip wave defects.

[0021] The laminar cooling section of the present invention is provided with a three-level laminar cooling mechanism, and an infrared imager is provided behind each level of the laminar cooling mechanism to detect the transverse temperature distribution of the strip at different temperature target nodes in real time, and then the gooseneck cooling water flow corresponding to different cooling stages is calculated using a formula to accurately control the transverse temperature of each section of the strip. At the same time, the gooseneck of the laminar cooling device is set to a staggered distribution, which can effectively prevent the transverse temperature of the strip from being distributed in a strip-like manner, improve the uniformity of the transverse temperature of the strip, reduce the transverse temperature difference of the strip, reduce the stress mutation caused by the transverse temperature difference, and improve the wave shape of the strip. During the laminar cooling process, the preset temperature of each level is a stepped temperature specifically set according to the phase transition temperature of different low-carbon steels, which can effectively ensure that the low-carbon steel is cooled steadily and gradually, and avoid plate defects caused by excessive local stress.

[0022] The present invention sets an aerosol cooling section at the rear end of laminar cooling, sprays cooling water in a mist form with high pressure, fully contacts the surface of the strip, and makes the surface of the strip evenly cooled; at the same time, by fully opening the middle aerosol nozzle and opening the two end aerosol nozzles in alternate rows, the cooling effect of the middle of the strip is higher than that of the edge of the strip, and the temperature difference between the middle and the edge of the strip is further reduced, thereby increasing the uniformity of the structure. The strip with basically eliminated the temperature difference of the strip enters the water replenishment cooling section, in which the cooling water uses a uniform water volume, and the middle and the edge of the strip are cooled synchronously to reach a temperature suitable for coiling. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The utility model will be further described below in conjunction with the accompanying drawings.

[0024] Figure 1 It is an overall schematic diagram of the cooling device of the utility model;

[0025] Figure 2 It is a schematic diagram of the arrangement of the gooseneck tube of the laminar cooling mechanism;

[0026] Figure 3 is a schematic diagram of the arrangement of the aerosol nozzles of the aerosol cooling mechanism;

[0027] In the figure, 1. finishing mill, 2. strip steel, 3. laminar roller, 4. first infrared imager, 5. first-stage laminar cooling mechanism, 6. second infrared imager, 7. second-stage laminar cooling mechanism, 8. third infrared imager, 9. third-stage laminar cooling mechanism, 10. fourth infrared imager, 11. cooling manifold, 12. gooseneck, 13. aerosol cooling mechanism, 14. aerosol manifold, 15. aerosol nozzle, 16. high-pressure pump, 17. fifth infrared imager, 18. water supply cooling mechanism, 19. sixth infrared imager, 20. coiler. DETAILED DESCRIPTION

[0028] The utility model will be further described below in conjunction with the accompanying drawings.

[0029] A uniform cooling device for hot-rolled low-carbon steel strip, such as Figure 1 As shown, it includes a laminar cooling section, a mist cooling section and a water cooling section which are sequentially arranged between the finishing mill group 1 and the coiler 20. The high-temperature low-carbon steel strip 2 after hot rolling passes through the cooling device under roller conveyance, and after being cooled to a temperature suitable for coiling by cooling water, enters the coiler 20 for coiling.

[0030] The laminar cooling section includes a first-level laminar cooling mechanism 5, a second-level laminar cooling mechanism 7 and a third-level laminar cooling mechanism 9 which are arranged in sequence. An infrared imager for real-time monitoring of the transverse temperature of the strip 2 is arranged upstream of each level of laminar cooling mechanism, specifically: a first infrared imager 4 arranged between the outlet end of the finishing mill 1 and the first-level laminar cooling mechanism 5, a second infrared imager 6 arranged between the first-level laminar cooling mechanism 5 and the second-level laminar cooling mechanism 7, and a third infrared imager 8 arranged between the second-level laminar cooling mechanism 7 and the third-level laminar cooling mechanism 9; in addition, a fourth infrared imager 10 is arranged downstream of the third-level laminar cooling mechanism 9.

[0031] The first-stage laminar cooling mechanism 5, the second-stage laminar cooling mechanism 7, and the third-stage laminar cooling mechanism 9 have the same structure, and all include four rows of cooling headers 11 arranged side by side, one end of the cooling header 11 is connected to the cooling water supply pipe, and the other end is connected to two rows of gooseneck tubes 12, each row includes n gooseneck tubes 12, and the n gooseneck tubes 12 are evenly distributed along the width direction of the low-carbon strip steel 2, and the gooseneck tubes 12 in adjacent rows are staggered. Figure 2 Each of the gooseneck tubes 12 is provided with an electric valve and a flow meter with adjustable opening to realize the individual control of the cooling water flow. The cooling water is sprayed out through the gooseneck tubes 12 to cool the low-carbon steel strip 2.

[0032] The flow rate of the gooseneck tube 12 is determined according to the difference between the actual temperature of the steel strip 2 detected by the infrared imager and the cooling target temperature. Therefore, in order to accurately detect the transverse temperature of the steel strip 2, the detection points of each infrared imager are the same as the number of gooseneck tubes 12 of the downstream laminar cooling mechanism, that is, each infrared imager is provided with n temperature detection points, which are evenly distributed along the transverse direction of the steel strip 2 and correspond to the positions of the gooseneck tubes 12 of the laminar cooling mechanism. The number and position of the detection points correspond to the arrangement positions of the gooseneck tubes 12 one by one, and the transverse temperature distribution of the steel strip 2 is fully detected.

[0033] The number n of gooseneck tubes 12 is adjusted according to the width of the steel strip 2, usually 25≤n≤30; in this embodiment, n=28, that is, each row of cooling headers 11 is connected to two rows of gooseneck tubes, each row is provided with 28 gooseneck tubes, and the 28 gooseneck tubes are evenly arranged along the width direction of the steel strip 2; the diameter of the gooseneck tube is 20-23mm, and the spacing between two adjacent gooseneck tubes 12 is 43-45mm. Correspondingly, each of the infrared imagers is provided with 28 temperature detection points, which are evenly distributed along the transverse direction of the steel strip 2, corresponding one by one to the positions of the 28 gooseneck tubes 12 of the laminar cooling mechanism.

[0034] The calculation formula for the cooling water flow rate of the gooseneck pipe is:

[0035] Q=4.7*H*v*φ*ρ s *C S *DT / (ρ w *C W *△T*n)

[0036] Where, Q is the gooseneck flow rate, m 3 / h;

[0037] H——rolling thickness of strip steel, mm;

[0038] v——rolling speed, m / s;

[0039] Φ——gooseneck diameter, mm;

[0040] ρ s ——Strip density, kg / m 3

[0041] C S ——Specific heat capacity of strip steel, KJ / kg·℃;

[0042] DT——Strip temperature drop DT, °C; DT=strip initial temperature T0-cooling target temperature T1;

[0043] ρ w ——Density of water, kg / m 3 ;

[0044] C W ——Specific heat capacity of water, KJ / kg·℃;

[0045] △T——temperature rise of water, ℃;

[0046] n——number of goosenecks, n.

[0047] Among them, the strip temperature drop DT is the difference between the initial temperature of the strip and the cooling target temperature. The initial temperature of the strip is the strip temperature obtained by the infrared imager located upstream of the laminar cooling mechanism. The cooling target temperature is the preset temperature set by the technicians according to the specific composition of the low-carbon strip and the ferrite transformation termination temperature. The difference between the two is the specific temperature that the strip needs to be cooled when passing through the laminar cooling mechanism. Specifically, the cooling target temperature of the first-level laminar cooling mechanism> the cooling target temperature of the second-level laminar cooling mechanism> the cooling target temperature of the third-level laminar cooling mechanism. The cooling target temperature of the third-level laminar cooling mechanism is the ferrite transformation termination temperature of the low-carbon strip. Through the step-by-step cooling of the three-level cooling group, the strip completes the transformation from austenite to ferrite.

[0048] For example, for the plain carbon steel series represented by Q235B and the high-quality carbon steel represented by 20 steel, the final rolling temperature is 860±15°C, the cooling target temperature of the first-level laminar cooling mechanism is 810°C, the cooling target temperature of the second-level laminar cooling mechanism is 760°C, and the cooling target temperature of the third-level laminar cooling mechanism is 720°C. In the actual production process, the hot rolling temperature and cooling target temperature are adaptively adjusted according to the specific types of low-carbon strip steel.

[0049] The temperature detected by the infrared imager is transmitted to the control system in real time. After receiving the temperature data and calculating the flow rate of the gooseneck tube 12, the control system transmits the control signal to the electric valve controlling the gooseneck tube 12, and feeds back the percentage to the electric valve, and adjusts the opening of the electric valve to adjust the flow rate of the gooseneck tube 12.

[0050] The aerosol cooling section is provided with five groups of aerosol cooling mechanisms 13, with a total length of 20m to 25m. Each group of aerosol cooling mechanisms 13 is provided with a plurality of aerosol nozzles 15, which are arranged in an array, and their width covers the transverse width of the strip steel 2, and the adjacent rows of aerosol nozzles 15 are arranged alternately. In the present utility model, the array form of the aerosol nozzles 15 of each group of aerosol cooling mechanisms 13 is 3 rows × 20, and the 20 nozzles are evenly arranged along the transverse direction of the strip steel 2, see Figure 3 The aerosol nozzle 15 is connected to the cooling water supply pipe through the aerosol header 14 . A high-pressure pump 16 is installed on the aerosol header 14 . The high-pressure pump 16 pressurizes the cooling water to 0.8-1.2 MPa and then sprays it out through the aerosol nozzle 15 .

[0051] In this embodiment, the nozzle has a length of 28 to 30 mm and an inner diameter of 0.5 to 0.8 mm. In actual use, the nozzle can be adaptively adjusted according to factors such as water pressure.

[0052] In order to further eliminate the temperature difference between the middle and edge of the steel strip 2 and improve the uniformity of the overall crystal structure of the steel strip 2, among the five groups of aerosol cooling mechanisms 13, the 10 aerosol nozzles 15 located in the middle are all in an open state, and the 5 aerosol nozzles 15 located at both ends are opened in alternate rows, and the aerosol nozzles 15 opened in adjacent rows are staggered, so that the cooling water flow in the middle of the steel strip 2 is greater than the cooling water flow at the edge of the steel strip 2.

[0053] A fifth infrared imager 17 is also provided downstream of the gas mist cooling section for detecting the transverse temperature distribution of the steel strip 2 after gas mist cooling.

[0054] The water supply cooling section includes four-stage water supply cooling mechanisms 18 arranged in sequence. The water supply cooling mechanism 18 has a similar structure to the laminar cooling mechanism, but no electric valve is provided on the gooseneck pipe 12, and the flow of the gooseneck pipe 12 adopts a uniform water volume. Each stage of the water supply cooling mechanism 18 is independently controlled, and water can be automatically supplied row by row through the water supply mechanism according to the temperature of the strip steel 2 at the outlet of the mist cooling section and the coiling temperature, until the temperature of the strip steel 2 is cooled to the coiling temperature.

[0055] A sixth infrared imager 19 is also provided downstream of the water-supplementing cooling section for detecting the temperature of the steel strip 2 after water-supplementing cooling.

[0056] It should be emphasized that the laminar cooling mechanism, the mist cooling mechanism 13 and the water supplement cooling mechanism 18 are all two groups, which are symmetrically arranged above and below the steel strip 2. Due to the influence of gravity, the pressure of the cooling water of the cooling mechanism below the steel strip 2 is usually higher than the pressure of the cold water above the steel strip 2, so as to achieve synchronous cooling of the upper and lower sides of the steel strip 2.

[0057] In this embodiment, the cooling water pressure of the laminar cooling mechanism / aerosol cooling mechanism / water supplement cooling mechanism located above the steel strip 2 is 4.6KPa-4.8KPa, and the cooling water pressure of the laminar cooling mechanism / aerosol cooling mechanism / water supplement cooling mechanism located below the steel strip 2 is about 5.2KPa-5.4KPa, and the difference between the two is not less than 0.6KPa. Among them, the cooling water of the aerosol cooling mechanism 13 needs to be pressurized twice.

[0058] The working process of the utility model is:

[0059] The low carbon steel billet is rolled into low carbon strip steel by rough rolling unit and finishing rolling unit. The temperature of the low carbon strip steel is 895℃, and the temperature difference between the strip steel surface and the inside of the strip steel is 50~80℃.

[0060] The low-carbon strip enters the laminar cooling section for cooling. After the first-stage laminar cooling mechanism, the strip temperature drops to 820°C, and the temperature difference between the strip surface and the inside of the strip drops to 30-55°C; after the second-stage laminar cooling mechanism, the strip temperature drops to 760°C, and the temperature difference between the strip surface and the inside of the strip drops to 20-37°C; after the third-stage laminar cooling mechanism, the strip temperature drops to 720°C, allowing the strip to enter the temperature range of transformation from austenite to ferrite, and the temperature difference between the strip surface and the inside of the strip drops to 10-15°C.

[0061] The low-carbon strip passes through the gas mist cooling section, and cooling water is sprayed out in the form of high-pressure mist, which fully contacts and cools the surface of the strip. The strip temperature drops to 670°C, and the temperature difference between the strip surface and the inside of the strip drops to 4°C to 8°C.

[0062] The low-carbon strip passes through the water-supply cooling section, where cooling water is sprayed out in a spraying form. After the strip temperature drops to 620°C, it is sent to the coiler for coiling.

[0063] During the cooling process of low-carbon strip steel, uniform and controllable temperature drop control replaces the original disordered and random natural cooling, which eliminates the inconsistency between the center and the outside caused by the disordered cooling process to the greatest extent, reduces the stress in the center and the outside of the strip steel, and effectively improves the strip steel shape; at the same time, the phase transition temperature is effectively controlled during the cooling process, achieving the stable transformation of ferrite and pearlite, the grain structure is uniform, and the mechanical properties of the strip steel are further enhanced.

[0064] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A uniform cooling device for hot-rolled low-carbon steel strip, characterized in that: The invention comprises a laminar cooling section, an air mist cooling section and a water supply cooling section which are sequentially arranged between a finishing mill (1) and a coiler (20); the laminar cooling section comprises a first-stage laminar cooling mechanism (5), a second-stage laminar cooling mechanism (7) and a third-stage laminar cooling mechanism (9) which are sequentially arranged; an infrared imager for real-time monitoring of the transverse temperature of the strip is arranged upstream of each stage of the laminar cooling mechanism.

2. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 1, characterized in that: The first-stage laminar cooling mechanism (5), the second-stage laminar cooling mechanism (7), and the third-stage laminar cooling mechanism (9) have the same structure, and all include four rows of cooling headers (11) arranged side by side, one end of the cooling header (11) is connected to a cooling water supply pipe, and the other end is connected to two rows of gooseneck tubes (12), the gooseneck tubes (12) are evenly distributed along the width direction of the low-carbon steel strip, and the gooseneck tubes (12) in adjacent rows are arranged in a staggered manner.

3. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 2, characterized in that: The number of the gooseneck tubes (12) is 25 to 30, and the diameter of the gooseneck tubes (12) is 20 mm to 23 mm.

4. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 3 is characterized in that: Each gooseneck tube (12) is provided with an electric valve with an adjustable opening.

5. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 4, characterized in that: The detection points of each infrared imager are the same as the number of gooseneck tubes (12) of the downstream laminar cooling mechanism, and the number and positions of the detection points correspond one-to-one to the arrangement positions of the gooseneck tubes (12).

6. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 1, characterized in that: Five groups of aerosol cooling mechanisms (13) are arranged in the aerosol cooling section, and each group of aerosol cooling mechanisms (13) is provided with a plurality of aerosol nozzles (15). The aerosol nozzles (15) are arranged in an array, and their width covers the transverse width of the steel strip (2). The aerosol nozzles (15) are connected to the cooling water supply pipe through an aerosol header (14), and a high-pressure pump (16) is installed on the aerosol header (14).

7. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 6, characterized in that: The aerosol nozzle (15) has a length of 28-30 mm and an inner diameter of 0.5-0.8 mm.

8. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 7, characterized in that: The array form of the aerosol nozzles (15) is 3 rows×20, and the 20 aerosol nozzles (15) are evenly arranged along the transverse direction of the steel strip.

9. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 8, characterized in that: The ten aerosol nozzles (15) located in the middle are all in an open state, and the five aerosol nozzles (15) located at both ends are in an open state in alternate rows, and the aerosol nozzles (15) opened in adjacent rows are arranged in a staggered manner.

10. The uniform cooling device for hot-rolled low-carbon steel strip according to claim 1, characterized in that: A first infrared imager (4) is arranged between the outlet end of the finishing mill (1) and the first-stage laminar cooling mechanism (5); a second infrared imager (6) is arranged downstream of the first-stage laminar cooling mechanism (5); a third infrared imager (8) is arranged downstream of the second-stage laminar cooling mechanism (7); a fourth infrared imager (10) is arranged downstream of the third-stage laminar cooling mechanism (9); a fifth infrared imager (17) is arranged downstream of the mist cooling section; and a sixth infrared imager (19) is arranged downstream of the water replenishment cooling section.

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