A method for producing cold-rolled steel plates with a large aspect ratio based on a continuous annealing unit

Abstract

This invention discloses a method for producing large aspect ratio cold-rolled steel sheets based on a continuous annealing unit, comprising the following steps: obtaining large aspect ratio continuous cold-rolled steel sheet raw materials; controlling the linkage between the tension and deviation detection value of the large aspect ratio continuous cold-rolled steel sheet raw materials in the furnace heating section; refining the roughness standards of furnace rolls in each section of the furnace area, clarifying the inspection standards for new rolls, and refining the inspection methods and standards for furnace roll roughness during gas furnace start-up maintenance, thereby achieving control over the roughness of the furnace rolls in the continuous annealing furnace; designing the initial crown of the furnace rolls in different working areas to form an initial crown control scheme for the furnace rolls; and optimizing the furnace roll thermal crown fan control scheme based on the different ranges of temperature difference between the furnace rolls and strip steel in different sections, combined with the cross-sectional area of ​​the large aspect ratio continuous cold-rolled steel sheet raw materials, optimizing and solidifying the speed and current values ​​of the thermal crown fans in different sections according to the material thickness and width, thereby achieving process control of the continuous annealing unit in producing large aspect ratio cold-rolled steel sheets.

Description

Technical Field

[0001] This invention belongs to the field of cold rolling and relates to a method for producing cold-rolled steel plates with a large aspect ratio based on a continuous annealing unit, which is applicable to the production of cold-rolled plates. Background Technology

[0002] Currently, major steel companies generally use continuous annealing units for post-rolling heat treatment of cold-rolled strip steel. Continuous annealing units are more capable than bell-type annealing units for producing high-surface-grade and special-performance steel plates. Continuous annealing units are suitable for producing high-surface-grade and high-strength cold-rolled strip steel, offering advantages that bell-type annealing furnaces cannot match. However, due to the large length (2600 meters) and height (45 meters at its highest point) of the continuous annealing furnace, the strip steel, especially the increasingly common high width-to-thickness ratio steel plates, faces a higher risk of deviation and hot wrinkling defects during production. This risk is compounded by variations in specifications, speed, and temperature during annealing scheduling. The core factors determining whether strip steel will deviate or develop hot wrinkling defects are the surface condition of the furnace rolls (roughness—which determines the stability of the tension inside the furnace and indirectly reflects the crown of the furnace rolls), the thermal crown of the furnace rolls (which determines the lateral force on the strip steel, resulting in whether the strip steel deviates or warps), and the tension inside the furnace (which determines the wrap angle between the strip steel and the furnace rolls, determines the deflection torque on the strip steel, and provides the corrective torque). Due to deficiencies in design and maintenance, the Ansteel continuous annealing unit lacks necessary detection and control schemes for the surface condition and thermal crown of the furnace rolls. The surface roughness of the furnace rolls does not differentiate between the working positions of the rolls, and the roughness range is set too wide. The required surface roughness Ra is 3-6 μm, and due to different service cycles, the surface roughness matching between adjacent rolls is poor, significantly affecting the actual tension in different sections of the furnace, causing the actual tension to fluctuate by approximately 0.3 kN compared to the set value. Meanwhile, since the crown of the furnace rolls is set at +60µm based on the cold, ambient temperature, the difference in temperature between the roll surface and body in the unloaded and loaded zones due to variations in furnace gas, strip temperature, and heat exchange during operation causes drastic changes in roll crown. In the heated zone, the rolls contract due to contact with the cooler strip in the loaded zone, while in the unloaded zone, they expand due to contact with the hot furnace gas. Therefore, the roll shape in the heated zone changes from the initial positive crown in the cold state to no crown or even negative crown, causing strip misalignment. In the cooled zone, the thermal deformation trend in the unloaded and loaded zones is exactly the opposite of the heated zone; the roll shape changes from the initial positive crown in the cold state to an even greater positive crown, easily leading to thermal wrinkling defects. Furthermore, insufficient tension in the heating section or failure to adjust misalignment promptly will exacerbate the misalignment, while excessive tension increases the transverse compressive stress on the strip, further intensifying thermal wrinkling defects. Therefore, in the early stages of production, there is a significant risk of belt slippage, breakage, and thermal wrinkling defects, which could lead to belt breakage accidents, produce defective products, and seriously affect the yield of continuously annealed steel plates and the progress of contract execution.Therefore, this patent conducts in-depth research and innovation on how to optimize raw material quality requirements, optimize the initial roll shape design of furnace rolls, optimize the roll surface roughness design, optimize the furnace roll thermal crown control method, and optimize the furnace tension adjustment control scheme. Without increasing equipment investment, it reduces the probability of furnace deviation and thermal wrinkling of steel plates with large width-to-thickness ratios, ensures that no strip breakage occurs when producing extreme varieties in the continuous annealing area, ensures that the strip steel passes through the production line stably and safely, and guarantees the stable operation of the unit and the steel plate quality meets the requirements.

[0003] The existing publicly disclosed patent CN202110024594.X, "A Strip Correction Device and Method in a Continuous Annealing Furnace," is characterized by the following: the device includes guide rollers, alignment sensors, a correction control system, and a correction execution mechanism; the guide rollers are arranged in an alternating, uniform pattern, and each guide roller has a central threaded through hole; the alignment sensors are symmetrically arranged above and below the two sides of the strip, with the alignment sensor on the upper side of the strip being a transmitting sensor and the alignment sensor on the lower side being a receiving sensor, and the magnetic field emitted by the transmitting sensor being perpendicular to the strip side; the alignment... The sensor is connected to the web correction control system; the web correction actuator includes a servo motor, a drive shaft, a drive gear, a driven gear, a ring sleeve, a wedge block, and a connecting rod; the servo motor is connected to the web correction control system; the connecting rod is located at the center of the ring sleeve, the wedge block is located at the front end of the connecting rod, the wedge block, the connecting rod, and the ring sleeve are tightly fitted together, and the outer surface of the wedge block is provided with a reverse thread; the wedge blocks are respectively placed on both sides of the central threaded through hole of each guide roller; the driven gear is coaxially connected to the outside of the ring sleeve, the drive gear is connected to the servo motor through the drive shaft, and the drive gear and the driven gear mesh. The main design content of this patent is basically the adjustment method and device for the mechanical structure of the guide roller, etc., lacking technical solutions for furnace tension, wrap angle, and furnace roller surface condition applicable to the production of large width-to-thickness cold-rolled steel plates. Therefore, it is insufficient to support the stable production control of large width-to-thickness continuous annealing steel plates.

[0004] The existing patent CN202010685311.1, "An Automatic Correction Control Method for a Cold-Rolled Strip Steel Continuous Annealing Furnace," is characterized by the following steps: Step 1: Real-time monitoring of tension data, strip steel plate specification data, hydraulic cylinder correction positions, and strip steel correction CPC positions in each area of ​​the continuous annealing furnace PLC system. When the absolute value of the sum of the hydraulic cylinder correction amount at any position and the strip steel correction amount at any position is greater than 10mm, Step 2 is executed; Step 2: Based on the strip steel deviation status, strip steel plate specification data, and the corresponding heating curve, obtain... A suitable tension setting procedure is used to calculate the tension setting procedure using a neural network N. After the tension setting procedure is calculated, step three is executed. Step three: Run for 10 seconds according to the tension setting procedure obtained in step two. Compare the initial deviation state in step two with the tension deviation state after 10 seconds. Set the initial deviation state as d(0) and the tension deviation state after 10 seconds as d(10). Calculate the current strip correction effect. The calculation formula is: , where t is the current running time, d is the evaluation value of the current deviation state, and y is the sum of the strip correction amount and the oil cylinder correction amount in each area of ​​the continuous annealing furnace. The internal zones are: preheating zone (JPF), heating zone (RTF), soaking zone (SF), slow cooling zone (SCS), rapid cooling zone (FC), over-aging zone 1 (OS1), over-aging zone 2 (OS2), and final cooling zone (FCS). The execution results will be stored in the neural network database. The neural network N will be retrained based on the modified neural network database, and the critical value for strip deviation will be set to 10mm. Based on the execution results, the following operation options will be selected: 1) If the strip deviation position increases, it indicates that the tension setting procedure in step two is unreasonable, and step four will be executed; 2) If the strip deviation position... If the deviation is reduced but still greater than 10mm, proceed to step five; 3) If the deviation of the strip is less than 10mm, proceed to step six; Step four: Reset the current tension setting parameters to the initial tension setting parameters of step two, and re-execute step two. At this time, since the control model has been modified, different tension setting parameters will be re-executed; Step five: If the execution result in step three indicates that the deviation of the strip has decreased, it means that the tension setting procedure corresponding to step three has effectively reduced the strip deviation. Re-execute step two while keeping the current state unchanged; Step six: The automatic correction operation has been completed, and the automatic correction function is exited. The main design content of this patent is basically the adjustment and control method of the furnace tension system, but it does not involve the linkage control of the furnace roll surface state, furnace roll shape, and related control of raw material plate shape. Therefore, it is not sufficient to support the control of stable production of large width-to-thickness continuous annealing steel plates. Summary of the Invention

[0005] To solve the above problems, the technical solution adopted by the present invention is: a method for producing cold-rolled steel plates with a large width-to-thickness ratio based on a continuous annealing unit, comprising the following steps:

[0006] Obtain raw materials for continuous cold-rolled steel plates with a large aspect ratio;

[0007] The tension of large aspect ratio continuous cold-rolled steel sheet raw material in the furnace heating section is controlled in conjunction with the deviation detection value;

[0008] The roughness standards of the furnace rollers in each section of the furnace area are refined, the inspection standards for new rollers are clarified, and the inspection methods and standards for the roughness of the furnace rollers during the gas furnace start-up and maintenance are refined to achieve control over the roughness of the furnace rollers in the continuous annealing furnace.

[0009] The initial crown of the furnace rolls in different working areas is designed. For furnace rolls that tend to develop towards positive crown during operation, the initial crown is designed to be no greater than 0.2-0.4 mm. For furnace rolls that tend to develop towards negative crown during operation, the initial crown is designed to be no less than 0.4-0.6 mm, thus forming a furnace roll initial crown control scheme.

[0010] The control scheme for the furnace roll thermal crown fan was optimized. The optimized control scheme adopts the different range of temperature difference between the furnace roll and the strip in different sections, combined with the cross-sectional area of ​​the large width-to-thickness ratio continuous cold-rolled steel sheet raw material. The speed and current values ​​of the thermal crown fan in different sections are optimized and fixed according to the material thickness and width, so as to realize the process control of the continuous annealing unit to produce large width-to-thickness ratio cold-rolled steel sheets.

[0011] Furthermore, the shape of the large aspect ratio cold-rolled steel sheet raw material needs to meet the following requirements:

[0012] Requirements for the control of the rolling process of cold-rolled steel sheet raw materials with large width-to-thickness ratio and the criteria for judging the shape of the rolled steel sheet after rolling.

[0013] Furthermore, the control requirements for the machine rolling process of the large aspect ratio continuous cold-rolled steel plate raw material are as follows:

[0014] I. Tension deviation requirements between stands: During normal rolling, the tension deviation of each stand must be controlled within ±15KN;

[0015] II. All production materials are uniformly controlled by micro-edge waviness: the two sides are raised, the middle is concave, and the vertical coordinate of the edge is 0.25;

[0016] III. The closed-loop control of the bending roll of the fifth work roll is kept within 50%.

[0017] Furthermore: the criteria for judging the shape of the large width-to-thickness ratio continuous cold-rolled steel sheet raw material after rolling include:

[0018] I. The required I-value for the post-rolling sheet shape meter is as follows:

[0019] S0-S4, materials with a thickness ≤1.0mm 2.5 S7 / S8, Level 780 and above 15.0 S5 / S6 5.0

[0020] II. The following are the standards for inspecting and controlling the shape of the finished product after rolling:

[0021]

[0022]

[0023] Furthermore: the process of controlling the linkage between the tension and deviation detection value of the large width-to-thickness ratio continuous cold-rolled steel sheet raw material in the furnace heating section is as follows:

[0024] In the mainline secondary control system of the continuous annealing unit, the raw materials of various steel types and specifications in the heating section are assigned values ​​according to two categories: normal state and special state, as shown in the table below:

[0025]

[0026] The correction device calls the tension values ​​for normal and special states in the table above based on different ranges of the detected deviation. Specifically, when the actual deviation is within the range of -3mm to +3mm, the tension control program executes the tension value in the normal state column of the table above. When the deviation exceeds the range of -3mm to +3mm, the tension control program executes the tension value in the special state column of the table above.

[0027] Furthermore, the roughness standards of the furnace rollers in each section of the furnace area are refined, the inspection standards for new rollers are clarified, and the inspection methods and standards for the roughness of the furnace rollers during the gas furnace start-up maintenance are refined. The control scheme formed to control the roughness of the furnace rollers in the continuous annealing furnace is shown in the table below.

[0028]

[0029] Furthermore: The initial crowning control scheme for the furnace rollers is as follows.

[0030]

[0031]

[0032] Furthermore, the optimized furnace roller thermal crown fan control scheme is shown in the table below. The fan's 100% current value is 200A.

[0033]

[0034] Furthermore, the definition of the large width-to-thickness ratio is as follows: strip width (mm) / strip thickness (mm) ≥ 1900.

[0035] This invention provides a method for producing large width-to-thickness cold-rolled steel plates based on a continuous annealing unit. The purpose of this invention is to utilize existing annealing furnace welding machines and finishing machines to conduct in-depth research and innovation on how to optimize raw material quality requirements, optimize the initial roll shape design of furnace rolls, optimize roll surface roughness design, optimize furnace roll thermal crown control methods, and optimize furnace tension adjustment control schemes without increasing equipment investment. This aims to reduce the probability of furnace deviation and thermal wrinkling of large width-to-thickness steel plates, prevent strip breakage accidents when producing extreme varieties in the continuous annealing area, ensure the stable and safe passage of strip steel through the production line, and guarantee stable unit operation and steel plate quality that meets requirements.

[0036] This ensured the stable production of cold-rolled steel sheets with large width-to-thickness ratios in continuous annealing, prevented strip breakage accidents when producing extreme grades in the continuous annealing zone, ensured the stable and safe passage of strip steel through the production line, and guaranteed the stable operation of the unit and the quality of the steel sheets meeting the requirements. It required in-depth research and innovation on the control methods, raw material quality requirements, equipment functions, and key parameters of the continuous annealing unit when producing steel sheets with large width-to-thickness ratios, and ensured that no deviation accidents or hot wrinkling defects occurred. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a flowchart of the method. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0043] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0044] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0045] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0046] Figure 1 This is a flowchart of the method;

[0047] A method for producing cold-rolled steel sheets with a large aspect ratio based on a continuous annealing unit includes the following steps:

[0048] S1: Obtain raw materials for continuous cold-rolled steel plates with a large aspect ratio;

[0049] S2: Control the linkage between the tension and deviation detection value of the raw material of large width-to-thickness continuous cold-rolled steel plate in the heating section of the furnace;

[0050] S3: Refine the roughness standards of the furnace rollers in each section of the furnace area, clarify the inspection standards for new rollers, and refine the inspection methods and standards for the roughness of the furnace rollers during the gas furnace start-up and maintenance, so as to achieve control over the roughness of the furnace rollers in the continuous annealing furnace.

[0051] S4: Design the initial crown of the furnace rolls in different working areas. For furnace rolls that tend to develop towards positive crown during operation, the initial crown should be designed to be no greater than 0.2-0.4 mm. For furnace rolls that tend to develop towards negative crown during operation, the initial crown should be designed to be no less than 0.4-0.6 mm. This forms the initial crown control scheme for furnace rolls.

[0052] S5: Optimize the control scheme for the furnace roll thermal crown fan. The optimized control scheme for the furnace roll thermal crown fan adopts the different range of temperature difference between the furnace roll and the strip steel in different sections. Combined with the cross-sectional area of ​​the raw material of the large width-to-thickness continuous cold-rolled steel plate, the speed and current values ​​of the thermal crown fan in different sections are optimized and fixed according to the material thickness and width to realize the process control of the continuous annealing unit in producing large width-to-thickness cold-rolled steel plates.

[0053] Steps S1 / S2 / S3 / S4 / S5 are executed sequentially;

[0054] The definition of the large width-to-thickness ratio is as follows: strip width (mm) / strip thickness (mm) ≥ 1900.

[0055] The shape of the high aspect ratio cold-rolled steel sheet raw material needs to meet the following requirements:

[0056] 1. Controlling the shape and quality of raw materials for cold-rolled steel plates with large width-to-thickness ratios:

[0057] 1) Control requirements for the rolling process of large aspect ratio continuous cold-rolled steel plate raw material rolling mill;

[0058] I. Tension deviation requirements between stands: During normal rolling, the tension deviation of each stand must be controlled within ±15KN;

[0059] II. All production materials are uniformly controlled by micro-edge wave, with both sides raised and the middle recessed, and the vertical coordinate of the edge is 0.25;

[0060] III. The bending force of the fifth work roll must be controlled within 50%; it can only be the fifth work roll, and only the bending force of this one roll can determine the shape of the strip.

[0061] 2) Standards for judging the shape of cold-rolled steel plates with large width-to-thickness ratio after rolling:

[0062] I. Requirements for the I value of the post-rolling sheet shape meter are shown in Table 1.

[0063] Table 1. Mean I Value Requirements for Each Steel Grade

[0064] S0-S4 materials with a thickness ≤1.0mm 2.5 S7 / S8, Level 780 and above 15.0 S5 / S6 and others 5.0

[0065] S0-S8 refers to the steel strength grade, that is, the hardness classification of strip steel, which is a common term in the cold rolling and annealing industry.

[0066] II. Inspection and control standards for the actual shape of finished products after rolling, see Table 2.

[0067] Table 2 Standards for Inspecting the Shape of Rolled Plates

[0068]

[0069] The process of controlling the linkage between the tension and deviation detection value of the raw material of large aspect ratio continuous cold-rolled steel plate in the furnace heating section is as follows:

[0070] In the main line secondary control program, the tension values ​​of steel plates of various steel qualities and specifications in the heating section are assigned according to two categories: Normal and Special, as shown in Table 3. The tension control program calls the Normal and Special tension values ​​from Table 3 for different ranges of deviation detection values ​​by the correction device. Specifically, when the actual deviation detection value is within the range of -3mm to +3mm, the tension control program executes the tension value in the (Normal) column of Table 3; when the strip deviation detection value exceeds the range of -3mm to +3mm, the tension control program executes the tension value in the (Special) column of Table 3.

[0071] Table 3. Optimized and improved heating section tension table

[0072]

[0073]

[0074] Furthermore, the roughness standards for each section of the furnace rolls were refined. The inspection standards for new rolls were clarified, and the inspection methods and standards for the roughness of the furnace rolls during gas furnace start-up and maintenance were refined to achieve control over the roughness of the furnace rolls in the continuous annealing furnace; see Table 4 for details.

[0075] Table 4. Scheme for controlling the roughness of furnace rollers

[0076]

[0077] Furthermore, the specific process for controlling the crown of the furnace rolls is as follows:

[0078] 1) Initial crowning design of furnace rollers

[0079] The initial crown of the furnace rolls in different working areas should be designed reasonably. For furnace rolls that tend to develop towards positive crown during operation, the initial crown should be designed with a small positive crown; for furnace rolls that tend to develop towards negative crown during operation, the initial crown should be designed with a large positive crown. See Table 5 for details.

[0080] Table 5 Initial Crowning Control Scheme for Furnace Rollers

[0081] Preheating section 0.6 heating section 0.4 Heat exchanger section 0.2 Slow cooling section 0.2 fast cooling section 0.4 Final cooling phase 0.6

[0082] 2) Furnace roller thermal crown control scheme

[0083] The control scheme for the furnace roll thermal crown fan was optimized. The optimized scheme adopts the different range of temperature difference between the furnace roll and the strip steel in different sections, combined with the cross-sectional area of ​​the material (heat exchange intensity), and optimizes and solidifies the current value of the thermal crown fan in different sections according to the material thickness and width. The fan current is 200A when it is 100%, as shown in Table 6.

[0084] Table 6 Control Scheme for Furnace Roller Thermal Convexity Blower

[0085]

[0086] Example: The technical solutions for producing high aspect ratio cold-rolled steel sheets from strips of different specifications based on a continuous annealing unit are shown in the table below:

[0087]

[0088] Before the implementation of this technology, the overall scrap rate caused by defects such as belt misalignment, belt breakage, and thermal wrinkling was 0.79%. After implementation, the overall scrap rate was 0.34%. The annual throughput of continuous return was 750,000 tons, and the price difference between good and scrap products was 2,017 yuan / ton. Therefore, the benefit calculation is: 750,000 tons * (0.79% - 0.34%) * 2017 = 6,807,400 yuan.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit, characterized in that: Includes the following steps: Obtain raw materials for cold-rolled steel plates with a large aspect ratio; The tension of cold-rolled steel sheet raw material with a large width-to-thickness ratio in the furnace heating section is controlled in conjunction with the deviation detection value; The surface roughness standards for each section of the furnace rolls were refined, the inspection standards for new rolls were clarified, and the inspection methods and standards for furnace roll roughness during gas furnace start-up and maintenance were further refined to achieve control over the surface roughness of the furnace rolls in the continuous annealing furnace. The resulting control scheme is shown in the table below: The initial crown of the furnace rolls in different working areas is designed. For furnace rolls that tend to develop towards positive crown during operation, the initial crown is designed to be no greater than 0.2-0.4 mm of positive crown. For furnace rolls that tend to develop towards negative crown during operation, the initial crown is designed to be a positive crown of not less than 0.4-0.6mm, thus forming a furnace roll initial crown control scheme. The optimized control scheme for the furnace roll thermal crown fan adopts a method based on the different temperature differences between the furnace roll and the strip in different sections, combined with the cross-sectional area of ​​the raw material for cold-rolled steel plates with a large width-to-thickness ratio. The speed and current values ​​of the thermal crown fan in different sections are optimized and fixed according to the material thickness and width, so as to realize the process control of the continuous annealing unit in producing cold-rolled steel plates with a large width-to-thickness ratio.

2. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The shape of the cold-rolled steel sheet raw material with a large width-to-thickness ratio needs to meet the following requirements: the rolling process control requirements of the cold-rolled steel sheet raw material with a large width-to-thickness ratio and the inspection and judgment standards for the shape of the rolled steel sheet after continuous rolling.

3. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The rolling process control requirements for the large width-to-thickness ratio cold-rolled steel plate raw material are as follows: I. Tension deviation requirements between stands: During normal rolling, the tension deviation of each stand must be controlled within ±15KN; II. All production materials are uniformly controlled by micro-edge waviness: the two sides are raised, the middle is concave, and the vertical coordinate of the edge is 0.25; III. The closed-loop control of the bending roll of the fifth work roll is kept within 50%.

4. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The criteria for judging the shape of cold-rolled steel plates with a large width-to-thickness ratio after rolling include: I. The required I-value for the post-rolling sheet shape meter is as follows: II. The following are the standards for inspecting and controlling the shape of the finished product after rolling: 。 5. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The process of controlling the linkage between the tension and deviation detection value of the raw material of cold-rolled steel sheet with large width-to-thickness ratio in the furnace heating section is as follows: In the mainline secondary control system of the continuous annealing unit, the raw materials of various steel types and specifications in the heating section are assigned values ​​according to two categories: normal state and special state, as shown in the table below: The correction device calls the tension values ​​for normal and special states in the table above based on different ranges of the detected deviation. Specifically, when the actual deviation is within the range of -3mm to +3mm, the tension control program executes the tension value in the normal state column of the table above. When the deviation exceeds the range of -3mm to +3mm, the tension control program executes the tension value in the special state column of the table above.

6. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The initial crowning control scheme for the furnace rollers is as follows: 。 7. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The optimized furnace roller thermal crown fan control scheme is shown in the table below. The fan current is 200A at 100%.

8. The method for producing large aspect ratio cold-rolled steel plates based on a continuous annealing unit according to claim 1, characterized in that: The definition of the large width-to-thickness ratio is as follows: strip width (mm) / strip thickness (mm) ≥ 1900.

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