A method and system for controlling the shape stability of cold-hardened strip steel, and cold-hardened strip steel

Abstract

This invention discloses a method, system, and cold-hardened strip steel with a sheet shape stability of 0.1*1500mm. The method includes: modifying the roll profile and rolling passes of the single stand based on the sheet shape defects formed after the test product is rolled on a single stand; adjusting the reduction rate of each pass based on the sheet shape defects and rolling parameters of the test product; and after determining the reduction rate of the last pass, proportionally reducing the reduction rate of each preceding pass; when the test product has curled or wrinkled sheet shape defects, measuring and adjusting the levelness of the roll mandrel to keep it below a set levelness threshold; and when the levelness of the roll mandrel is kept below the set levelness threshold, rolling the target product according to the modified roll profile, rolling passes, and reduction rate to obtain the cold-hardened strip steel with an extreme thinness of 0.1*1500mm.

Description

Technical Field

[0001] This application relates to the field of single-stand production line steel rolling technology, and in particular to a method, system and cold-hardened strip steel plate shape stability control method. Background Technology

[0002] The required specification for the iron-nickel alloy austenitic monostructure strip steel is 0.1*1500mm, but the thinnest specification that can be produced at present is 0.1*1300mm. The extremely thinnest specification of 0.1*1500mm is a gap in the industry.

[0003] To produce 0.1*1500mm ultrathin strip steel, a trial rolling process is currently being conducted using the Qian'an 20-roll mill. However, the maximum rolled thickness is only 0.15mm, and the strip steel surface exhibits wrinkling defects. Therefore, there are currently no successful cases of producing 0.1*1500mm ultrathin strip steel. Summary of the Invention

[0004] This invention provides a method, system, and cold-hardened strip steel for controlling the shape stability of cold-hardened strip steel, in order to fill the production gap of 0.1*1500mm ultrathin strip steel.

[0005] To address the aforementioned technical problems, a first aspect of the present invention discloses a method for controlling the shape stability of cold-rolled strip steel, wherein the cold-rolled strip steel has a specification of 0.1*1500mm, and the method includes:

[0006] Based on the plate shape defects formed after the product was rolled on a single stand, the roll profile and rolling passes of the single stand were changed.

[0007] Adjust the reduction rate of each pass based on the plate defects and rolling parameters of the product being tested; and after determining the reduction rate of the last pass, reduce the reduction rate of each of the preceding passes in reverse proportion;

[0008] When the product being tested has a curled or wrinkled plate-shaped defect, the levelness of the roll mandrel is measured and adjusted to be below a set levelness threshold.

[0009] When the levelness of the roll mandrel is maintained below the set levelness threshold, the target product is rolled according to the changed roll profile, rolling pass and reduction rate to obtain the cold-hardened strip steel with an extreme thinness of 0.1*1500mm.

[0010] Preferably, changing the number of rolling passes of the single stand specifically includes:

[0011] The number of rolling passes is fixed at 5.

[0012] Preferably, the modification of the roll profile of the single stand includes:

[0013] The working roller of the single frame is replaced with a convex roller with a radius of 0.01mm, and a chamfered area with a rounded transition is added to the edge of the convex roller.

[0014] Preferably, the modification of the roll profile of the single stand further includes:

[0015] Keep the intermediate roller of the single frame as a flat roller, and adjust the length and depth of the chamfer of the intermediate roller of the single frame; wherein, the length of the chamfer of the intermediate roller is 520+60mm or 320+60mm, the depth of the chamfer of the intermediate roller is 0.857+0.069mm or 0.697+0.069mm, and the radius of the chamfer of the intermediate roller is 25000mm.

[0016] Preferably, the step of adjusting the reduction rate of each pass based on the plate defects and rolling parameters of the debugged product, and proportionally reducing the reduction rate of each preceding pass after determining the final pass reduction rate, specifically includes:

[0017] For the final pass reduction rate, the Hitchcock flattening radius calculation formula is used. The mapping relationship is used to increase the final pass reduction rate with the goal of satisfying the set condition for the roll flattening radius, so that the final pass reduction rate is ≥20%; where R′ is the roll flattening radius; R is the original roll radius; p is the rolling force per unit length of the roll; L is the length of the deformation zone after elastic flattening of the roll; v1 is the Poisson's ratio of the roll; Δh is the change in strip thickness, used to determine the final pass reduction rate, and is positively correlated with the final pass reduction rate; E1 is the elastic modulus of the roll.

[0018] Preferably, after determining the final pass reduction rate, the step of proportionally reducing the reduction rates of the preceding passes specifically includes:

[0019] After determining the final pass reduction rate, the reduction rates of the first 1-4 passes are reduced by more than 2% in reverse order.

[0020] Preferably, after determining the final pass reduction rate and then proportionally reducing the reduction rates of the preceding passes, the method further includes: controlling the rolling force of each pass to decrease by 200kN-500kN.

[0021] Preferably, the step of measuring and adjusting the levelness of the roll mandrel to bring it below a set levelness threshold specifically includes:

[0022] The levelness of the roll mandrel is adjusted by adding shims to the drive side and the operating side of the mandrel, so that the levelness of the roll mandrel is <0.15mm / m.

[0023] A second aspect of the present invention discloses a control system for stabilizing cold-rolled strip steel, comprising:

[0024] A control device is used to change the roll profile and rolling pass of the single stand based on the plate shape defects formed after the product is rolled in a single stand.

[0025] The mill adjustment device is used to adjust the reduction rate of each pass based on the plate shape defects and rolling parameters of the product being tested; and after determining the reduction rate of the last pass, to proportionally reduce the reduction rate of the preceding passes in the reverse direction.

[0026] A roll adjustment device is used to measure and adjust the levelness of the roll mandrel when the product being tested has curled or wrinkled plate-shaped defects, so that it is below a set levelness threshold.

[0027] The single stand is used to roll the target product according to the changed roll profile, rolling passes and reduction rate, when the levelness of the roll mandrel is maintained below the set levelness threshold, to obtain the cold-hardened strip steel with an extreme thinness of 0.1*1500mm.

[0028] Preferably, the control device is specifically used to fix the rolling passes to 5 passes.

[0029] Preferably, the control device is specifically used to replace the working roller of the single frame with a convex roller with a radius of 0.01 mm, and to add a chamfered area with a rounded transition at the edge of the convex roller.

[0030] Preferably, the control device is further configured to maintain the intermediate roller of the single frame as a flat roller and adjust the length and depth of the chamfer of the intermediate roller of the single frame; wherein the length of the chamfer of the intermediate roller is 520+60mm or 320+60mm, the depth of the chamfer of the intermediate roller is 0.857+0.069mm or 0.697+0.069mm, and the radius of the chamfer of the intermediate roller is 25000mm.

[0031] Preferably, the mill adjustment device is specifically used to calculate the flattening radius using the Hitchcock flattening radius formula for the final pass reduction rate. The mapping relationship is used to increase the final pass reduction rate with the goal of satisfying the set condition for the roll flattening radius, so that the final pass reduction rate is ≥20%; where R′ is the roll flattening radius; R is the original roll radius; p is the rolling force per unit length of the roll; L is the length of the deformation zone after elastic flattening of the roll; v1 is the Poisson's ratio of the roll; Δh is the change in strip thickness, used to determine the final pass reduction rate, and is positively correlated with the final pass reduction rate; E1 is the elastic modulus of the roll.

[0032] Preferably, the mill adjustment device is further configured to, after determining the final pass reduction rate, reduce the reduction rates of the preceding 1-4 passes by at least 2% respectively.

[0033] Preferably, the mill adjustment device is further used to control the rolling force of each pass to decrease by 200kN-500kN.

[0034] Preferably, the roll adjustment device is specifically used to adjust the levelness of the roll mandrel by adding shims on the mandrel drive side and the operation side, so that the levelness of the roll mandrel is <0.15mm / m.

[0035] In a third aspect, the present invention discloses a cold-hardened strip steel with a specification of 0.1*1500mm, which is obtained by rolling using the cold-hardened strip steel shape stability control disclosed in the aforementioned scheme.

[0036] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0037] In this solution, by analyzing the plate defects of the 0.1*1500mm ultrathin strip steel during the rolling process, such as edge waviness, edge pressure, and coiling wrinkles, the single-stand rolling parameters are adjusted by optimizing rolling parameters, changing roll shape, and adjusting roll spatial position. After adjustment, the 0.1*1500mm ultrathin cold-hardened strip steel can be rolled, thereby filling the production gap of 0.1*1500mm ultrathin strip steel.

[0038] 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. Attached Figure Description

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0040] In the attached diagram:

[0041] Figure 1 A schematic diagram illustrating the implementation process of a method for controlling the stability of cold-rolled strip steel according to an embodiment of the present invention is shown.

[0042] Figures 2-3 Example diagrams of two specifications of intermediate rollers according to an embodiment of the present invention are shown;

[0043] Figure 4 A schematic diagram of a control system for cold-hardened strip steel plate type stabilization according to an embodiment of the present invention is shown. Detailed Implementation

[0044] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0045] This invention discloses a method for controlling the shape stability of cold-rolled strip steel, mainly used for producing cold-rolled strip steel with a specification of 0.1*1500mm. See also... Figure 1 The method includes the following steps:

[0046] Step 11: Based on the plate shape defects formed after the product is rolled on a single stand, change the roll type and rolling passes of the single stand.

[0047] In this embodiment, the test product was only used for rolling 0.1*1500mm cold-hardened strip billets. Due to an edge-pressing problem occurring during rolling of extremely thin cold-hardened strip, the roll profile and rolling passes of the single stand were modified to fix the single-stand rolling passes at 5 passes.

[0048] When modifying the roll profile of a single-stand rolling mill, improvements were made to both the work rolls and intermediate rolls used in single-stand rolling. The work rolls are the ones that directly contact the billet, controlling its deformation to ultimately produce the product; these are motor-driven drive rolls. The intermediate rolls, also called support rolls, are rolls that resist the deformation of the work rolls under high rolling forces, supporting their operation.

[0049] Specifically, for the work rolls of a single stand, the flat rolls are replaced with convex rolls with a radius of 0.01 mm, and a chamfered area with a rounded transition is added to the edge of the convex roll. The reason for changing the work roll is that when the work roll is a flat roll, there is a 55 mm long slope transition area (approximately 155.6 degrees) on the edge of the roll surface. Although the flat roll also has a slope, the edge transition is a sharp point, which is not as good as the rounded chamfered state in terms of stress concentration and wear on the intermediate roll. Therefore, a chamfered area is added to the edge. The chamfer depth in this embodiment is limited as the slope portion gradually increases in plane length as the roll diameter decreases, and the chamfer depth increases accordingly. That is, the chamfer depth is deeper closer to the edge of the roll. In addition, the flat roll is replaced with a convex roll with a radius of 0.01 mm. Through the above structural settings, stress concentration can be achieved and wear on the intermediate roll can be reduced.

[0050] For the intermediate rolls of a single-stand mill, maintain them as flat rolls and adjust the length and depth of the chamfer on the intermediate rolls to avoid poor sheet shape caused by insufficient sheet shape control leading to excessive roll slippage. Specifically, the chamfer length is 520+60mm or 320+60mm, the chamfer depth is 0.857+0.069mm or 0.697+0.069mm, and the chamfer radius is 25000mm. (See also...) Figures 2-3 These are the two specifications of intermediate rollers disclosed in this embodiment.

[0051] After the modified rolls were put into use, there was no obvious wear in the chamfered area, the strip shape could be effectively controlled, and the rolling effect was good.

[0052] Step 12: Adjust the reduction rate of each pass based on the plate shape defects and rolling parameters of the product being tested. After determining the reduction rate of the final pass, proportionally reduce the reduction rate of each of the preceding passes in reverse order.

[0053] In this embodiment, it was found that the trial product of ultra-thin cold-hardened strip steel exhibited edge waviness at the mill exit during rolling. Analysis revealed that the previous mill reduction rate followed a principle of decreasing from high to low, with the final pass reduction rate being <10%, resulting in a reduction rate exceeding 40% in passes 1-4. This increased deformation led to severe deterioration of the strip shape. Furthermore, the high reduction rates in the first 1-4 passes caused severe work hardening of the strip, leading to a sharp increase in rolling force in the final pass, further worsening the strip shape and causing edge waviness at the mill exit, thus failing to meet the material supply requirements. Even with a small deformation in the 5th pass (final pass), the rolling force increased instead of decreasing, and the large deflection of the work roll system resulted in severe edge waviness in the strip. Therefore, the strip shape quality and stable rolling process during cold-hardened strip steel rolling are closely related to the load distribution across each pass. For the rolling of thin-gauge cold-hardened strip steel, a reasonable load distribution across each pass is extremely important.

[0054] Considering the aforementioned problem of edge waviness in the final rolling pass due to poor reduction ratio distribution in each pass, this embodiment can utilize empirical methods or reduction ratio formulas. Calculate the reduction rate for the first 1-4 passes; where μ is the reduction rate; Δh is the strip thickness compression, Δh = h 入 -h 出 h 入 This is the inlet thickness of this pass, which can also be considered as the outlet thickness of the previous pass, h. 出 This is the exit thickness for this pass.

[0055] Targeted improvements were made to the final pass reduction rate. After determining the final pass reduction rate, the reduction rates of the preceding passes were proportionally reduced in reverse order. This lowered the reduction rates of the first 1-4 passes, thereby reducing the deformation of thin-gauge cold-rolled strip and maintaining its shape. Furthermore, increasing the final pass reduction rate eliminated edge waviness in the thin-gauge cold-rolled strip, and the overall shape quality was improved through coordinated passes.

[0056] Specifically, the Hitchcock flattening radius calculation formula is used. The mapping relationship in the formula aims to increase the final pass reduction rate by ensuring the roll flattening radius meets the set conditions. This increases the final pass reduction rate from the original 10% to over 20%, effectively reducing the elastic flattening radius of the rolls and the ineffective rolling force caused by harmful roll contact. It also reduces the deflection deformation of the work roll system, thereby solving the edge waviness problem at the mill exit and improving the sheet shape quality of thin-gauge products. Where R′ is the roll flattening radius; R is the original roll radius; p is the rolling force per unit length of the roll; L is the length of the deformation zone after elastic flattening of the roll; v1 is the Poisson's ratio of the roll; Δh is the strip thickness compression, used to determine the final pass reduction rate, and is positively correlated with it. Specifically, based on the roll flattening radius meeting the set conditions, the strip thickness compression Δh is obtained, and the final pass reduction rate is obtained using the aforementioned publicly disclosed reduction rate calculation formula; E1 is the elastic modulus of the roll.

[0057] In this embodiment, after determining the reduction rate of the final pass, the reduction rates of the preceding passes are reduced proportionally in reverse: the reduction rates of the first 1-4 passes are reduced by more than 2% each, thereby optimizing the rolling load distribution system for each pass. For example, the reduction rates of the first 1-4 passes are reduced by the following proportions: 2%, 2.5%, 2%, and 3%, respectively.

[0058] In this embodiment, after the reduction rate of each preceding pass is reduced proportionally in the reverse direction, the rolling force of each pass is controlled to be reduced by 200kN-500kN.

[0059] Step 13: When the product being tested has a curled or wrinkled plate-shaped defect, measure and adjust the levelness of the roll mandrel to bring it below the set levelness threshold.

[0060] In this embodiment, analysis of the curling and wrinkling problems that occurred during rolling of the test product reveals that the spatial position of the mandrel has a significant impact on these defects. Therefore, when the test product exhibits curling and wrinkling defects, the levelness of the roll mandrel is adjusted by adding shims to both the drive and operating sides, ensuring that the levelness of the roll mandrel is <0.15mm / m. By adjusting the spatial position of the roll mandrel, the curling and wrinkling problem is resolved, thereby meeting production requirements.

[0061] Step 14: When the levelness of the roll mandrel is kept below the set levelness threshold, the target product is rolled according to the changed roll type, rolling pass and reduction rate to obtain a cold-hardened strip steel with an extreme thinness of 0.1*1500mm.

[0062] In this embodiment, the target product is also a billet used for rolling 0.1*1500mm ultra-thin strip steel, and it belongs to the same type of billet as the debugging product.

[0063] By analyzing the plate defects of the 0.1*1500mm ultrathin strip steel during the rolling process, such as edge waviness, edge pressure, and coiling wrinkles, the rolling parameters of the single stand were adjusted by optimizing the rolling parameters, changing the roll shape, and adjusting the roll spatial position. After this, the target product can be rolled to obtain the 0.1*1500mm ultrathin cold-hardened strip steel.

[0064] The solution in this invention can successfully produce cold-rolled steel strip with an ultra-thin 0.1*1500mm diameter, filling a gap in the industry and having significant implications for the rolling of ultra-thin cold-rolled steel strip. Based on an annual production of 200 tons of ultra-thin cold-rolled steel strip, the profit per ton is approximately 5000 yuan. Therefore, the actual profit of ultra-thin cold-rolled steel strip = production line * profit per ton of steel = 200 × 5000 = 1 million yuan, which can bring substantial profits to the industry.

[0065] Based on the same inventive concept, the following embodiments disclose a control system for stabilizing cold-rolled strip steel plates, see below. Figure 4 ,include:

[0066] Control device 41 is used to change the roll profile and rolling pass of the single stand based on the plate shape defects formed after the product is rolled in the single stand 44.

[0067] The mill adjustment device 42 is used to adjust the reduction rate of each pass based on the plate shape defects and rolling parameters of the product being tested; and after determining the reduction rate of the last pass, to reduce the reduction rate of each of the preceding passes in reverse proportion;

[0068] The roll adjustment device 43 is used to measure and adjust the levelness of the roll mandrel when the debugged product has a curled or wrinkled plate-shaped defect, so that it is below a set levelness threshold.

[0069] A single stand 44 is used to roll the target product according to the changed roll profile, rolling passes and reduction rate, while the levelness of the roll mandrel is maintained below the set levelness threshold, to obtain the cold-hardened strip steel with an extreme thinness of 0.1*1500mm.

[0070] In one alternative implementation, the control device 41 is specifically used to fix the rolling passes to 5 passes.

[0071] In one optional embodiment, the control device 41 is specifically used to replace the work roller of the single frame with a flat roller with a convex roller in the radial direction of 0.01mm, and to add a chamfered area with a rounded transition at the edge of the convex roller.

[0072] In an optional embodiment, the control device 41 is further configured to maintain the intermediate roller of the single frame as a flat roller and adjust the length and depth of the chamfer of the intermediate roller of the single frame; wherein the length of the chamfer of the intermediate roller is 520+60mm or 320+60mm, the depth of the chamfer of the intermediate roller is 0.857+0.069mm or 0.697+0.069mm, and the radius of the chamfer of the intermediate roller is 25000mm.

[0073] In one alternative embodiment, the mill adjustment device 42 is specifically used to calculate the flattening radius using the Hitchcock flattening radius formula for the final pass reduction rate. The mapping relationship is used to increase the final pass reduction rate with the goal of satisfying the set condition for the roll flattening radius, so that the final pass reduction rate is ≥20%; where R′ is the roll flattening radius; R is the original roll radius; p is the rolling force per unit length of the roll; L is the length of the deformation zone after elastic flattening of the roll; v1 is the Poisson's ratio of the roll; Δh is the change in strip thickness, used to determine the final pass reduction rate, and is positively correlated with the final pass reduction rate; E1 is the elastic modulus of the roll.

[0074] Preferably, the mill adjustment device 42 is further configured to, after determining the final pass reduction rate, reduce the reduction rates of the preceding 1-4 passes by a ratio of more than 2% in the opposite direction.

[0075] In one optional embodiment, the mill adjustment device 42 is further used to control the rolling force of each pass to decrease by 200kN-500kN.

[0076] In one alternative embodiment, the roll adjustment device 43 is specifically used to adjust the levelness of the roll mandrel by adding shims on the mandrel drive side and the operating side, so that the levelness of the roll mandrel is <0.15mm / m.

[0077] Based on the same inventive concept, the following embodiments disclose a cold-hardened strip steel with a specification of 0.1*1500mm, which is obtained by rolling using the cold-hardened strip steel plate shape stability control described in the aforementioned scheme.

[0078] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0079] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for controlling the shape stability of cold-rolled steel strip, characterized in that, The cold-hardened strip steel has a specification of 0.

1. 1500mm, the method includes: Based on the plate shape defects formed after single-stand rolling of the test product, the roll type and rolling passes of the single stand are modified. Specifically, the work rolls of the single stand are replaced from flat rolls to convex rolls with a radius of 0.01mm, and a chamfered area with a rounded transition is added to the edge of the convex rolls. The intermediate rolls of the single stand are kept as flat rolls, and the length and depth of the chamfer of the intermediate rolls are adjusted. Specifically, the length of the chamfer of the intermediate rolls is 520+60mm or 320+60mm, the depth of the chamfer of the intermediate rolls is 0.857+0.069mm or 0.697+0.069mm, and the radius of the chamfer of the intermediate rolls is 25000mm. The rolling passes are fixed at 5 passes. Adjust the reduction rate of each pass based on the plate defects and rolling parameters of the product being tested; and after determining the reduction rate of the last pass, reduce the reduction rate of each of the preceding passes in reverse proportion; When the product being tested has a curled or wrinkled plate-shaped defect, the levelness of the roll mandrel is measured and adjusted to be below a set levelness threshold. When the levelness of the roll mandrel is maintained below the set levelness threshold, the target product is rolled according to the modified roll profile, rolling passes, and reduction rate to obtain 0.

1. The cold-hardened strip steel with an extreme thinness of 1500mm.

2. The method as described in claim 1, characterized in that, The step of reducing the reduction rate of each preceding pass proportionally after determining the final pass reduction rate specifically includes: After determining the final pass reduction rate, the reduction rates for the first 1-4 passes are reduced by more than 2% in reverse order.

3. The method as described in claim 2, characterized in that, After determining the final pass reduction rate, and then proportionally reducing the reduction rates of the preceding passes, the method further includes: controlling the rolling force of each pass to decrease by 200 kN-500 kN.

4. The method as described in claim 1, characterized in that, The measurement and adjustment of the levelness of the roll mandrel to bring it below a set levelness threshold specifically includes: The levelness of the roll mandrel is adjusted by adding shims to the drive side and the operating side of the mandrel, so that the levelness of the roll mandrel is <0.15mm / m.

5. A cold-hardened strip steel plate type stable control system, characterized in that, include: A control device is used to modify the roll profile and rolling passes of a single-stand rolling mill based on the plate shape defects formed after the product is rolled in a test stand. Specifically, the work rolls of the single-stand are replaced from flat rolls to convex rolls with a radius of 0.01 mm, and a chamfered area with a rounded transition is added to the edge of the convex rolls. The intermediate rolls of the single-stand are kept flat, and the length and depth of the chamfer on the intermediate rolls are adjusted. Specifically, the length of the chamfer on the intermediate rolls is 520+60 mm or 320+60 mm, the depth of the chamfer is 0.857+0.069 mm or 0.697+0.069 mm, and the radius of the chamfer is 25000 mm. The rolling passes are fixed at 5 passes. The mill adjustment device is used to adjust the reduction rate of each pass based on the plate shape defects and rolling parameters of the product being tested; and after determining the reduction rate of the last pass, to proportionally reduce the reduction rate of the preceding passes in the reverse direction. A roll adjustment device is used to measure and adjust the levelness of the roll mandrel when the product being tested has curled or wrinkled plate-shaped defects, so that it is below a set levelness threshold. The single stand is used to roll the target product according to the modified roll profile, rolling passes, and reduction rate, while the levelness of the roll mandrel is maintained below the set levelness threshold, to obtain 0.

1. The cold-hardened strip steel with an extreme thinness of 1500mm.

6. A cold-hardened strip steel, characterized in that, The cold-hardened strip steel has a specification of 0.

1. 1500mm, obtained by rolling using the cold-hardened strip plate shape stability control method as described in any one of claims 1-4.

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