A method for producing an ultra-long low alloy plate having a thickness of 12 mm ≤ thickness ≤ 20 mm

Abstract

This invention belongs to the field of low-alloy high-strength structural steel production technology, specifically relating to a production method for ultra-long low-alloy steel plates with a thickness of 12mm ≤ 20mm. It includes: setting the initial cooling temperature for each stage, fine-tuning the roller speed and acceleration in tandem, precisely configuring the water volume and ratio in segments, precisely controlling the red-heat temperature within a narrow range, and using differentiated masking at the beginning and end combined with water spraying in the middle. Compared to existing technologies, this invention significantly improves cooling uniformity, resulting in more uniform and stable microstructure and properties; it thoroughly improves plate shape defects and significantly reduces residual stress; it achieves extremely high precision in controlling the red-heat temperature, enhancing performance stability; and it is suitable for mass production of long, reduced-length plates, improving production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of low-alloy high-strength structural steel production technology, specifically relating to a production method for ultra-long low-alloy plates with a thickness of 12mm≤20mm. Background Technology

[0002] Q355 (Chinese national standard) corresponds to European standard S355. It is a low-alloy high-strength structural steel, commonly used in buildings, bridges, and mechanical structural components. Specifications: Thickness 12–20 mm, belonging to medium-thick plates; relatively long, making it more difficult to control plate shape and temperature uniformity. Production process: Mostly hot-rolled followed by controlled cooling / laminar flow cooling or air cooling; sometimes, to simplify the process, a "comprehensive uniform cooling" method is used.

[0003] The core characteristics of extensive, uniform cooling are: it does not zon the cooling area according to precise paths, does not consider the subtle differences in steel grades, and does not meticulously track the thermal history of each plate. Instead, it features: 1. Uniform cooling regime: the same cooling parameters are used for the same batch or the entire coil of steel plates: water volume / pressure is roughly fixed; the cooling zone opening mode is consistent; the target range for final cooling temperature is relatively wide (e.g., only controlled to a certain approximate temperature range). 2. Simple equipment layout and control: the cooling zone operates on an on / off basis, rather than continuously adjusting the flow rate and spray angle; there is little dynamic tracking and feedback adjustment for individual plates. 3. Suitable for scenarios with a high degree of standardization: the product performance fluctuation range is relatively large; customers' requirements for plate shape, residual stress, and performance uniformity are not extremely stringent; there is a need to increase production and reduce operational complexity.

[0004] The key points of extensive cooling for 12–20 mm long reduced-weight steel plates are: 1. High risk of temperature uniformity: During the roller conveyor process, the cooling conditions at the head and tail of the long plates differ significantly: when the head first enters the cooling zone, the water temperature is lower and heat transfer is stronger; when the tail approaches the end of the cooling zone, the water temperature rises and the cooling capacity decreases. The cooling rate of a 12–20 mm thickness is inherently limited. If the water volume is insufficient or unevenly distributed, it can easily lead to: large temperature differences on the plate surface → asynchronous phase transformation → performance fluctuations; localized stress concentration → warping, wobbling, and waviness. 2. Difficulty in precisely ensuring performance stability: Q355 / S355 has certain requirements for yield strength and impact toughness. The cooling rate affects the ferrite / pearlite ratio and bainite formation. Extensive cooling cannot guarantee that every plate falls within the target cooling rate range, which may result in: some areas cooling too slowly → insufficient strength; some areas cooling too quickly → decreased toughness and increased residual stress. 3. Prominent issues related to plate shape and residual stress. During the cooling process, uneven cooling of the upper and lower surfaces and along the length of long, thick plates can easily lead to: longitudinal bending (arching or sagging); transverse waviness; and diagonal warping. Extensive cooling methods lack targeted corrective measures and often rely on subsequent straightening machines, increasing process costs. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems. For Q355 / S355 series 12-20mm long reduced-size plates (length ≥ 55m), a technical solution is adopted, which is a combination of thickness-graded refined rapid cooling, multi-parameter coordinated control, differentiated shielding at the head and tail, and central water spray-assisted uniform cooling. This solution is completely different from the extensive uniform cooling of existing technologies. The specific implementation method is as follows: A method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ 20mm includes: (1) Setting the cooling temperature for each stage: The starting cooling temperature is set to 800℃ ≥ 760℃, and the starting cooling temperature is positively correlated with the thickness. The cooling temperature is gradually increased by increasing the thickness to match the heat capacity of steel plates of different thicknesses, which makes up for the problem of rapid temperature drop and lag in heat exchange of thicker plates, and ensures uniform cooling starting temperature, laying the foundation for subsequent precise temperature control. (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed ranges from 1.2±0.2m / s to 1.7±0.2m / s, and there is a negative correlation between roller speed and thickness. The acceleration is 0.015~0.02 m / s². 2 Acceleration and thickness show a negative correlation trend; As the thickness increases, the roller speed gradually decreases, and the acceleration is simultaneously reduced slightly. By controlling the residence time of the steel plate in the cooling section, the cooling time is precisely controlled, and the red-hot temperature is narrowly controlled in conjunction with the water volume and water ratio. (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h~120 / 120 / 120m 3 / h, water volume and thickness show a positive correlation trend; The water ratio is 1.6 / 1.8 / 1.7~2.0 / 2.2 / 2.1, and the water ratio shows a positive correlation with the thickness. The water ratio is gradually increased as the thickness increases. The water ratio is used to regulate the cooling uniformity of the edge and the middle, so as to avoid the edge being too cold and the middle being insufficiently cooled. (4) Narrow-range precise control of the red temperature: The temperature for the reddening process is 600-625℃; a narrow range is set according to the thickness specifications, and the temperature fluctuation of the entire board is ensured to be minimal through real-time fine adjustment of roller speed and acceleration; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The head shading coefficient is uniformly set to 1.0 to prevent the head from getting cold quickly. The tail section has a shielding length of 25,000-35,000 mm, with an upper shielding coefficient of 0.70-0.75 and a lower shielding coefficient of 0.8-0.95, to accommodate different tail thicknesses and temperature drop rates. The water spray is turned on throughout the process to help balance the temperature in the middle of the steel plate, eliminate cooling dead zones in the middle area, and further improve the temperature uniformity of the entire plate.

[0006] Key technical points of this invention: (1) Core innovation: For the Q355 / S355 series 12-20mm long reduction plate, the coordinated control process of setting the cooling temperature, number of manifold opening groups, roller speed and acceleration according to the thickness is achieved to realize the precise matching of cooling intensity and heat capacity of reduction plate of different thicknesses. This is different from the existing unified process and is the core protection point.

[0007] (2) Key innovations: The red temperature is precisely controlled within a narrow range according to specifications, and the water volume and water ratio are finely adjusted in stages to achieve precise control of the phase change process and ensure uniform and stable performance.

[0008] (3) Key auxiliary innovation points: The tail shielding length and shielding coefficient are set according to the thickness difference, and the head is uniformly shielded + the middle water spray assists in cooling, which solves the problem of uneven cooling at the head and tail of long steel plates and large temperature deviation in the middle, and optimizes the plate shape and the consistency of the overall plate performance.

[0009] (4) Supporting innovations: The dynamic control logic of gradually reducing the roller speed and slightly lowering the acceleration as the thickness increases precisely controls the cooling dwell time and further improves the accuracy of the reddening temperature control.

[0010] As a preferred option, the production method of the above-mentioned ultra-long low alloy plate with a thickness of 12mm≤20mm further includes step (1) as follows: Differentiated opening of manifold groups: opening 10~14 manifold groups, with the number of manifolds showing a positive correlation with the thickness. The number of manifolds opened and the arrangement pattern are strictly matched according to the thickness. By arranging the manifolds in sections and opening them differently, the cooling intensity and thickness are precisely matched, avoiding overcooling of thin specifications and insufficient cooling rate of thick specifications.

[0011] As a preferred embodiment, the above-mentioned production method for ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm is applicable to ultra-long low-alloy steel plates with a thickness of 12mm: (1) Cooling start-up temperature setting: 765℃ ≥ Cooling start-up temperature ≥ 760℃; Differentiated manifold group number enabled: 10 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.7 ± 0.2 m / s, and the acceleration is 0.02 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.6 / 1.8 / 1.7; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 25000-30000mm.

[0012] As a preferred embodiment, the above-mentioned production method for ultra-long low-alloy steel sheets with a thickness of 12mm ≤ thickness ≤ 20mm is applicable to ultra-long low-alloy steel sheets with a thickness of 14mm: (1) Cooling start-up temperature setting: 770℃ ≥ Cooling start-up temperature ≥ 765℃; Differentiated manifold group number enabled: 11 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.6 m / s ± 0.2 m / s, and the acceleration is 0.02 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.7 / 1.9 / 1.8; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 20000-25000mm.

[0013] As a preferred embodiment, the above-mentioned production method for ultra-long low-alloy steel sheets with a thickness of 12mm ≤ 20mm is applicable to ultra-long low-alloy steel sheets with a thickness of 16mm: (1) Cooling start-up temperature setting: 770℃ ≥ Cooling start-up temperature ≥ 765℃; Differentiated manifold group number enabled: 13 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.45±0.2m / s to 1.55±0.2m / s, and the acceleration is 0.02m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.8 / 2.0 / 1.9; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 25000-30000mm.

[0014] As a preferred embodiment, the above-mentioned production method for ultra-long low-alloy steel sheets with a thickness of 12mm ≤ 20mm is applicable to ultra-long low-alloy steel sheets with a thickness of 18mm: (1) Cooling start-up temperature setting: 800℃ ≥ Cooling start-up temperature ≥ 770℃; Differentiated manifold group number enabled: 13 or 14 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.4 ± 0.2 m / s, and the acceleration is 0.018 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 120m 3 / h, water ratio is 1.9 / 2.1 / 2.0; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 605-625℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 30,000-35,000 mm.

[0015] As a preferred embodiment, the above-mentioned production method for ultra-long low-alloy steel sheets with a thickness of 12mm ≤ thickness ≤ 20mm is applicable to ultra-long low-alloy steel sheets with a thickness of 20mm: (1) Cooling start-up temperature setting: 800℃ ≥ Cooling start-up temperature ≥ 770℃; Differentiated manifold group number enabled: 13 or 14 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.2 ± 0.2 m / s, and the acceleration is 0.015 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 120m 3 / h, water ratio is 2.0 / 2.2 / 2.1; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 605-625℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 30,000-35,000 mm.

[0016] As a preferred embodiment, the production method of the above-mentioned ultra-long low alloy plate with a thickness of 12mm ≤ 20mm is wherein the length of the ultra-long low alloy plate is ≥ 55m.

[0017] The aforementioned production method for ultra-long low-alloy steel plates with a thickness of 12mm to 20mm utilizes ultra-fast cooling equipment, specifically an ultra-fast cooling system (ADCOS-PM system). The ultra-fast cooling equipment is divided into three control segments: segments 1-4, 5-12, and 13-24. Each of these three segments has unified control parameters and serves a cooling function; the three-segment design is adopted for ease of control.

[0018] The above-mentioned production method for ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm refers to the water flow rate, measured in cubic meters per second (m³). 3 / h; Water ratio refers to the flow rate of the upper manifold and the flow rate of the lower manifold. Lower manifold flow rate = water volume × water ratio.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Cooling uniformity is greatly improved and the microstructure and properties are uniform and stable: the multi-parameters of manifold, water volume, water ratio and roller speed are matched according to the thickness to completely solve the problem of heat exchange mismatch for different thicknesses. With the uniform cooling of the central spray water, the temperature deviation of the longitudinal, transverse and upper and lower surfaces of the steel plate is significantly reduced. The metallographic structure is uniform and dense, without abnormal banded structure and uneven grain phenomenon. The difference in mechanical properties between the same plate is greatly reduced. The yield strength, tensile strength, elongation and low temperature toughness are all stable and meet the standards. It is suitable for the strength and toughness balance requirements after the reduction of the component of the plate, and avoids the performance deficiency caused by the reduction of the component.

[0020] (2) Plate shape defects are completely improved and residual stress is significantly reduced: Differentiated manifold opening and head and tail shielding design accurately control the cooling rate of the upper and lower surfaces and the head and tail of the steel plate, avoiding the problems of warping and bending caused by excessive temperature difference between the upper and lower surfaces and uneven temperature drop at the head and tail. The flatness of the steel plate meets the standard, and there is no need for additional repeated straightening. The residual stress is greatly reduced, and the cutting and processing in the later stage will not be deformed. The yield and first-pass rate are significantly improved, and the rework cost is reduced.

[0021] (3) The red temperature control accuracy is extremely high and the performance stability is enhanced: narrow red temperature control + multi-parameter coordinated fine adjustment avoids the red temperature being too high or too low, ensuring that the austenite to ferrite + pearlite phase transformation is sufficient and uniform, ensuring that the steel plate strength meets the standard and maintaining good low temperature toughness. The performance consistency of the long steel plate is improved, solving the pain point of large performance fluctuation at the beginning and end of the existing technology.

[0022] (4) Adapted to mass production of long-length reduced-size plates, improving production efficiency: All parameters are fixed according to thickness, eliminating the need for frequent rough on-site adjustments. It is suitable for continuous production of long steel plates with a length of ≥55m, with strong cooling process stability and controllable production rhythm, taking into account both product quality and production efficiency, and adapting to the needs of industrialized mass production.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Detailed Implementation

[0024] The following description provides numerous specific details to offer a more thorough understanding of the technical solutions provided by this invention. However, it will be apparent to those skilled in the art that the technical solutions provided by this invention can be implemented without one or more of these details.

[0025] In this embodiment of the invention, the specific operation steps not explicitly stated are conventional techniques in the field.

[0026] Example 1 This embodiment provides a method for producing an ultra-long low alloy plate with a thickness of 12mm and a length of 62m.

[0027] 12mm reduced-gauge Q355 steel plate, 62m in length, set cooling temperature 760℃, actual temperature 765℃, 10 manifolds open (223300), roller speed 1.7m / s, acceleration 0.02m / s². 2 Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.6 / 1.8 / 1.7; red temperature is 613℃, hitting the 600-620℃ range; head upper and lower obscuration coefficient is uniformly 1.0; tail obscuration length is 28000mm, upper obscuration coefficient is 0.7, lower obscuration coefficient is 0.8, water spray is on throughout.

[0028] Example 2 This embodiment provides a method for producing an ultra-long low alloy plate with a thickness of 14mm and a length of 55m.

[0029] 14mm reduced-gauge Q355 steel plate, 55m in length, set cooling temperature 765℃, actual temperature 770℃, 11 sets of manifolds open (222320), roller conveyor speed 1.6m / s, acceleration 0.02m / s². 2 Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.7 / 1.9 / 1.8; red temperature is 610℃, hits the 600-620℃ range; head upper and lower obscuration coefficient is uniformly 1.0; tail obscuration length is 21000mm, upper obscuration coefficient is 0.7, lower obscuration coefficient is 0.85, mid-spray is on throughout.

[0030] Example 3 This embodiment provides a method for producing an ultra-long low-alloy plate with a thickness of 16mm and a length of 61m.

[0031] 16mm reduced-gauge Q355 steel plate, 61m in length, set cooling temperature 765℃, actual temperature 770℃, 13 manifolds open (222222), roller speed 1.45m / s, acceleration 0.02m / s². 2 Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.8 / 2.0 / 1.9; red temperature is 615℃, hits the 600-620℃ range; head upper and lower obscuration coefficient is uniformly 1.0; tail obscuration length is 30000mm, upper obscuration coefficient is 0.75, lower obscuration coefficient is 0.80, mid-spray is on throughout.

[0032] Example 4 This embodiment provides a method for producing an ultra-long low-alloy plate with a thickness of 18mm and a length of 61m.

[0033] 18mm reduced-gauge Q355 steel plate, 61m in length, set cooling temperature 770℃, actual temperature 782℃, 14 manifolds open (222322), roller speed 1.4m / s, acceleration 0.018m / s². 2 Water volume is 120 / 120 / 120m 3 / h, water ratio is 1.9 / 2.1 / 2.0; red temperature is 611℃, hitting the 605-625℃ range; head and tail obscuration coefficient is uniformly 1.0; tail obscuration length is 32000mm, upper obscuration coefficient is 0.75, lower obscuration coefficient is 0.80, and mid-spray is on throughout.

[0034] Example 5 This embodiment provides a method for producing an ultra-long low alloy plate with a thickness of 20 mm and a length of 73 m.

[0035] 20mm reduced-gauge Q355 steel plate, 73m in length, set cooling temperature 772℃, actual temperature 774℃, 14 manifolds open (222322), roller speed 1.4m / s, acceleration 0.015m / s². 2 Water volume is 120 / 120 / 120m 3 / h, water ratio is 2.0 / 2.2 / 2.1; red temperature is 611℃, hitting the 605-625℃ range; head upper and lower obscuration coefficient is uniformly 1.0; tail obscuration length is set to 32000mm, upper obscuration coefficient is 0.70, lower obscuration coefficient is 0.8, and mid-spray is on throughout.

[0036] The performance parameters and components of each embodiment are as follows: Table 1

[0037] Yield strength: The stress at which a material begins to undergo plastic deformation; Tensile strength: The maximum stress a material can withstand before it fractures; Elongation after fracture: reflects the material's ability to undergo plastic deformation; Z1 / Z2 / Z3: 0 (Z-axis performance index, usually the reduction of area; no delamination defect was detected here). Yield-to-tensile strength ratio: Yield strength / tensile strength; the lower the value, the higher the safety. Impact energy: The energy absorbed by the three specimens in the impact.

[0038] Table 2

[0039] (unit%) Comparative Example 1 The difference from Example 1 is that the water volume is 120 / 120 / 100m³. 3 / h, water ratio is 1.4 / 1.6 / 1.5.

[0040] Result: The steel plate exhibited a turtle-back bend, and the degree of bend significantly increased from 3mm to 6mm / 7mm / 5mm, which does not meet the standard requirement of ≤4mm.

[0041] Comparative Example 2 The difference from Example 2 is that the water volume is 120 / 120 / 100m³. 3 / h, water ratio is 1.5 / 1.7 / 1.6.

[0042] Results: The steel plate exhibited a turtle-back bend, with the degree of bend significantly increasing from 2mm to 5mm / 8mm / 4mm. In some areas, the degree of turtle-back bend exceeded the standard, failing to meet the standard requirement of ≤4mm.

[0043] Comparative Example 3 The difference from Example 3 is that the water volume is 150 / 150 / 130m³. 3 / h, water ratio is 1.8 / 2.0 / 1.9.

[0044] Result: Due to the increased water content on the upper and lower surfaces, the reheating temperature of the steel plate decreased after rapid cooling, from 615℃ to 595℃, which did not fall within the 600-620℃ range. As a result, the elongation of the steel plate was only 19.5%, which was unqualified and resulted in downgraded products, seriously affecting product quality.

[0045] Comparative Example 4 The difference from Example 4 is that the water volume is 90 / 90 / 90m³. 3 / h, water ratio is 1.9 / 2.1 / 2.0; Result: Due to the reduced water content on the upper and lower surfaces, the cooling intensity of the upper and lower surfaces of the steel plate decreased, and the red-hot temperature was 630℃, which did not fall within the 605-625℃ range. After testing, the yield strength of the steel plate was 340MPa, which did not meet the performance requirements.

[0046] Comparative Example 5 The difference from Example 5 is that the water volume is 120 / 120 / 120m³. 3 / h, water ratio is 1.8 / 2.0 / 1.9.

[0047] Result: The steel plate exhibited a turtle-back bend, with the degree of bend significantly increasing from 3mm to 6mm / 6mm / 5mm. In some areas, the degree of turtle-back bend exceeded the standard, failing to meet the standard requirement of ≤4mm.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing an ultra-long low-alloy steel plate with a thickness of 12mm ≤ 20mm, characterized in that, include: (1) Setting the cooling temperature for each stage: The starting cooling temperature is set to 800℃ ≥ 760℃, and the starting cooling temperature is positively correlated with the thickness. (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed ranges from 1.2±0.2m / s to 1.7±0.2m / s, and there is a negative correlation between roller speed and thickness. The acceleration is 0.015~0.02 m / s². 2 Acceleration and thickness show a negative correlation trend; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h~120 / 120 / 120m 3 / h, water volume and thickness show a positive correlation trend; The water ratio is 1.6 / 1.8 / 1.7~2.0 / 2.2 / 2.1, and the water ratio shows a positive correlation with the thickness. (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-625℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The head occlusion coefficient is uniformly set to 1.

0. The tail section has a shielding length of 25,000-35,000 mm, an upper shielding coefficient of 0.70-0.75, and a lower shielding coefficient of 0.8-0.

95. The water spray is on throughout the entire process.

2. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1, characterized in that, Step (1) also includes: Differentiated opening of manifold group number: 10 to 14 manifold groups are opened, and the number of manifolds is positively correlated with the thickness.

3. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1 or 2, characterized in that, For ultra-long low-alloy steel plates with a thickness of 12mm: (1) Cooling start-up temperature setting: 765℃ ≥ Cooling start-up temperature ≥ 760℃; Differentiated manifold group number enabled: 10 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.7 ± 0.2 m / s, and the acceleration is 0.02 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.6 / 1.8 / 1.7; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 25000-30000mm.

4. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1 or 2, characterized in that, For ultra-long low-alloy steel plates with a thickness of 14mm: (1) Cooling start-up temperature setting: 770℃ ≥ Cooling start-up temperature ≥ 765℃; Differentiated manifold group number enabled: 11 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.6 m / s ± 0.2 m / s, and the acceleration is 0.02 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.7 / 1.9 / 1.8; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 20000-25000mm.

5. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1 or 2, characterized in that, For ultra-long low-alloy steel plates with a thickness of 16mm: (1) Cooling start-up temperature setting: 770℃ ≥ Cooling start-up temperature ≥ 765℃; Differentiated manifold group number enabled: 13 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.45±0.2m / s to 1.55±0.2m / s, and the acceleration is 0.02m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 100m 3 / h, water ratio is 1.8 / 2.0 / 1.9; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 600-620℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 25000-30000mm.

6. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1 or 2, characterized in that, For ultra-long low-alloy steel plates with a thickness of 18mm: (1) Cooling start-up temperature setting: 800℃ ≥ Cooling start-up temperature ≥ 770℃; Differentiated manifold group number enabled: 13 or 14 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.4 ± 0.2 m / s, and the acceleration is 0.018 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 120m 3 / h, water ratio is 1.9 / 2.1 / 2.0; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 605-625℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 30,000-35,000 mm.

7. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1 or 2, characterized in that, For ultra-long low-alloy steel plates with a thickness of 20mm: (1) Cooling start-up temperature setting: 800℃ ≥ Cooling start-up temperature ≥ 770℃; Differentiated manifold group number enabled: 13 or 14 manifold groups enabled; (2) Coordinated fine-tuning of roller speed and acceleration: The roller speed is 1.2 ± 0.2 m / s, and the acceleration is 0.015 m / s². 2 ; (3) Precise segmentation and configuration of water volume and water ratio settings: Water volume is 120 / 120 / 120m 3 / h, water ratio is 2.0 / 2.2 / 2.1; (4) Narrow-range precise control of the red temperature: The temperature for the red glow to appear is 605-625℃; (5) Differentiated masking at the front and rear + mid-range water spray assistance: The shielding length is 30,000-35,000 mm.

8. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1, characterized in that, The length of the ultra-long low alloy plate is ≥55m.

9. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 1, characterized in that, The production equipment used is an ultra-fast cooling system.

10. The method for producing ultra-long low-alloy steel plates with a thickness of 12mm ≤ thickness ≤ 20mm according to claim 9, characterized in that, The ultra-fast cooling equipment is controlled in three stages.

Images