A method and system for controlling breakage of cold-hardened strip steel, and cold-hardened strip steel.

Abstract

This invention discloses a method, system, and cold-hardened strip for controlling strip breakage, wherein the cold-hardened strip has a specification of 0.1*1500mm. The method includes: determining the rolling passes of the single stand for a single-stand rolling operation to address strip breakage incidents during single-stand rolling of the test product; adjusting the rolling parameters of each pass in the single stand; the rolling parameters include one or more of the following: reduction amount, uncoiling tension, relative position of shifting rolls, and roll profile; rolling the target product using the adjusted rolling parameters of each pass, and controlling the mill to start at low speed for coiling after the last pass is completed.

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 for controlling strip breakage. 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 strip breakage, thereby filling the production gap for 0.1*1500mm ultra-thin strip steel.

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

[0006] To address the strip breakage incident during single-stand rolling of the test product, the rolling passes of the single stand are determined.

[0007] Adjust the rolling parameters for each pass in the single stand; the rolling parameters include one or more of the following: reduction amount, uncoiling tension, relative position of the shifting rolls, and roll profile;

[0008] The target product is rolled using the adjusted rolling parameters for each pass, and after the last pass is completed, the mill is started at low speed to perform the coiling process.

[0009] Preferably, the belt breakage accident includes: rolling belt breakage accident, belt misalignment breakage accident, and belt breakage accident during idle running.

[0010] Preferably, different rolling passes are used for different types of strip breakage accidents.

[0011] Preferably, adjusting the rolling parameters for each pass in the single stand specifically includes:

[0012] The reduction in the first pass was reduced from 0.55 mm to 0.4 mm, and the unwinding tension in the first pass was reduced from 55 MPa to 35 MPa.

[0013] Adjust the mill shape control strategy for the second pass, and adjust the relative position of the shifting rolls in the second pass from 40mm to 60mm, and increase the bending roll of the work roll from 200kN to 400kN;

[0014] In the 3rd-5th or 3rd-6th passes, the work roll of the single frame is replaced with the minimum work roll with a diameter of 140mm, and the roll shape of the minimum work roll is optimized.

[0015] Preferably, the adjustment of the mill shape control strategy for the second pass specifically involves changing the mill shape control strategy for the second pass from the edge wave control mode to the micro edge wave mode.

[0016] Preferably, the roughness of the minimum working roll is 0.1 μm and the roll crown is 0.01 μm.

[0017] Preferably, during the acceleration of the rolling speed from 0 to 30 mpm in each pass, the rolling force is used as the starting standard for starting the machine.

[0018] Preferably, in the event of a strip breakage accident during the debugging of the product, the speed at which the rolling mill is started at a low speed for the coiling process is controlled to be below 20 mpm.

[0019] A second aspect of the present invention discloses a strip breakage control system for cold-hardened strip steel, wherein the cold-hardened strip steel has a specification of 0.1*1500mm and comprises:

[0020] A pass control device is used to determine the rolling pass of a single stand in response to a strip breakage accident during single-stand rolling of a test product.

[0021] A parameter adjustment device is used to adjust the rolling parameters of each pass in the single stand; the rolling parameters include one or more of the following: reduction amount, uncoiling tension, relative position of the rolls, and roll profile;

[0022] The work roll control device is used to roll the target product using the adjusted rolling parameters for each pass, and to control the mill to start at low speed for the coiling process after the last pass is completed.

[0023] Preferably, the belt breakage accident includes: rolling belt breakage accident, belt misalignment breakage accident, and belt breakage accident during idle running.

[0024] Preferably, different rolling passes are used for different types of strip breakage accidents.

[0025] Preferably, the parameter adjustment device is specifically used for:

[0026] The reduction in the first pass was reduced from 0.55 mm to 0.4 mm, and the unwinding tension in the first pass was reduced from 55 MPa to 35 MPa.

[0027] Adjust the mill shape control strategy for the second pass, and adjust the relative position of the shifting rolls in the second pass from 40mm to 60mm, and increase the bending roll of the work roll from 200kN to 400kN;

[0028] In the 3rd-5th or 3rd-6th passes, the work roll of the single frame is replaced with the minimum work roll with a diameter of 140mm, and the roll shape of the minimum work roll is optimized.

[0029] Preferably, the parameter adjustment device is further used to: modify the mill shape control strategy of the second pass from edge wave control mode to micro edge wave mode.

[0030] Preferably, the roughness of the minimum working roll is 0.1 μm and the roll crown is 0.01 μm.

[0031] Preferably, during the acceleration of the rolling speed from 0 to 30 mpm in each pass, the rolling force is used as the starting standard for starting the machine.

[0032] Preferably, in the event of a strip breakage accident during the debugging of the product, the speed at which the rolling mill is started at a low speed for the coiling process is controlled to be below 20 mpm.

[0033] In a third aspect, the present invention discloses a cold-hardened strip steel with a specification of 0.1*1500mm, wherein the cold-hardened strip steel is rolled using the strip breakage control method for cold-hardened strip steel described in the above technical solution.

[0034] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0035] In this solution, by analyzing the strip breakage accident of the 0.1*1500mm ultrathin strip steel during single-stand rolling, targeted measures are taken to prevent strip breakage accidents during the rolling process by determining the rolling passes, optimizing the rolling parameters of each pass, and controlling the low-speed start-up of the rolling mill after the last pass is completed for coiling. This fills the production gap of 0.1*1500mm ultrathin strip steel.

[0036] 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

[0037] 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.

[0038] In the attached diagram:

[0039] Figure 1 A flowchart of a method for controlling the breakage of cold-hardened strip steel according to an embodiment of the present invention is shown;

[0040] Figure 2 A schematic diagram of a strip breakage control system for cold-hardened strip steel according to an embodiment of the present invention is shown. Detailed Implementation

[0041] 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.

[0042] This invention discloses a method for controlling strip breakage in cold-rolled steel strip. This method is used to produce cold-rolled steel strip with a specification of 0.1*1500mm, specifically addressing strip breakage accidents that occur during the rolling process. See also... Figure 1 The method includes the following steps:

[0043] Step 11: For the strip breakage accident during single-stand rolling of the test product, determine the number of rolling passes for the single stand.

[0044] In this embodiment, the test product is only used for rolling 0.1*1500mm cold-hardened strip steel billets.

[0045] Generally speaking, belt breakage accidents can occur in three stages: threading, high-speed rolling, and tail-swing. Various belt breakage accidents that occur during rolling mainly include: rolling belt breakage accidents, belt breakage accidents due to deviation, and belt breakage accidents due to idling.

[0046] In the production of extremely thin strip products, strip breakage during rolling is the main cause affecting the stable production of extremely thin cold-rolled steel strip, and it poses the greatest threat. Since billets generally require multiple rolling passes to become finished products, and based on the characteristics of single-stand rolling, the number of start-ups per stand is generally more than five. In each rolling pass, especially the last three passes, it is necessary to increase the rolling force to thin the strip. However, this increased rolling force can lead to severe roll deflection and deformation, resulting in strip breakage. Strip breakage during rolling can occur at any stage of the process, and there are various causes. For example, breakage during start-up occurs when the strip is pressed against the rolling mill for an extended period during the start-up and shutdown phases, causing severe localized thinning of the strip and leading to a breakage accident. Breakage due to interlayer misalignment is caused by fluctuations in uncoiling tension.

[0047] Strip misalignment and breakage are defects caused by tension during the rolling process. Strip breakage due to dry running occurs because 0.1*1500mm cold-hardened strip steel is an extremely thin product; its actual thickness is lower than the design thickness of the current production line, making welding and threading impossible.

[0048] A belt breakage accident refers to a situation in the rolling-coiling process where, after the steel has been rolled by the rolling mill, the drive belt detaches from the rim or slips as it enters the coiling equipment. In this case, the drive belt loses its traction force on the steel, preventing the steel from entering the coiling equipment normally and causing a production interruption.

[0049] In this embodiment, different rolling passes can be adaptively selected to address different strip breakage incidents. For example, for a strip breakage incident occurring during product testing, the rolling passes per stand are controlled to be 5. For a strip breakage incident occurring during product testing due to misalignment, the rolling passes per stand are controlled to be 6. As another example, 5 rolling passes are typically used, but if a pre-set incident occurs, the number of rolling passes is increased to 6. For example, starting failure, strip shape defects, etc., can all lead to increased rolling passes.

[0050] Step 12: Adjust the rolling parameters for each pass in a single stand.

[0051] In this embodiment, the rolling parameters include one or more of the following: reduction amount, uncoiling tension, relative position of the shifting rolls, and roll profile.

[0052] During the adjustment of rolling parameters for each pass, different rolling problems are encountered in each pass. Therefore, the control measures to prevent rolling strip breakage accidents are described in the following examples for each pass.

[0053] The reduction in the first pass was reduced from 0.55 mm to 0.4 mm, and the uncoiling tension was reduced from 55 MPa to 35 MPa. The reasons are as follows: The primary goal of the first pass is to minimize the strip thickness. However, during the commissioning rolling process, it was found that excessive reduction in the first pass (greater than 0.55 mm) led to frequent strip breakage accidents during startup. Therefore, reducing the reduction in the first pass from 0.55 mm to 0.4 mm effectively controlled strip breakage during startup. Furthermore, since the incoming material for the first pass is annealed, an improperly set uncoiling tension can cause interlayer misalignment during uncoiling, resulting in instantaneous tension fluctuations and subsequent strip breakage accidents. Therefore, reducing the uncoiling tension in the first pass from 55 MPa to 35 MPa effectively solved the problem of interlayer misalignment and strip breakage.

[0054] The key to preventing strip breakage in the second pass is to prevent roll jamming and strip breakage accidents due to deviation. Because the edge waviness mode in the second pass can cause the actual strip edge waviness to exceed 40 IU, roll jamming accidents can occur during product testing under this mode. Therefore, in this embodiment, the mill shape control strategy for the second pass is adjusted from the edge waviness control mode to a micro-edge waviness mode to resolve the roll jamming accident. Furthermore, adjusting the relative position of the shifting rolls in the second pass from 40mm to 60mm and increasing the work roll bending from 200kN to 400kN significantly improves rolling stability and prevents strip breakage accidents as seen in the second pass.

[0055] In passes 3-5 or 3-6, a sharp increase in rolling force leads to deterioration of the strip shape, causing strip breakage. To avoid strip breakage accidents caused by abnormally high rolling force, the rolling force is controlled by replacing the work rolls and increasing their crown. Specifically, the diameter range of the work rolls on a single stand for rolling 0.1*1500mm cold-hardened strip is controlled between 140mm and 170mm. Therefore, in this embodiment, the work rolls on the single stand are replaced with the smallest work rolls with a diameter of 140mm. Rolling with the smallest work rolls reduces the rolling force, and the roll profile of the smallest work rolls is optimized to control the roughness of the smallest work rolls to 0.1μm and the roll crown to 0.01μm. By changing the roll profile, the rolling force in each pass is effectively controlled, reducing the rolling force from 2100t to less than 1000t. As the strip thins, after a single pass on a single stand is completed, the next pass is started.

[0056] It is worth noting that the rolling parameters for the final pass need to be referenced from the rolling results of the previous pass. For example, the rolling parameters for the 6th pass are determined based on the rolling conditions of the 5th pass, and generally bear 20%-40% of the load of the 5th pass.

[0057] Furthermore, since 0.1*1500mm cold-rolled strip is an extremely thin strip, during the acceleration of the rolling speed from 0 to 30mpm, parameters such as tension, bending rolls, and rolling force on a single stand need to be rapidly adjusted to ensure the strip thickness and shape. Overshooting these parameters can lead to strip breakage. To address this issue and ensure strip thickness and shape, constant rolling force is used as the starting standard during the acceleration of the rolling speed from 0 to 30mpm in each pass, avoiding strip breakage accidents caused by abnormal parameter fluctuations. In addition, tension thresholds can be set to prevent breakage due to tension overshoot, and constant shape control measures can be implemented. For example, if the actual tension value falls below 20% of the set value, the mill protection interlock is triggered; another example is that shape control is automatically shut off during startup, using optimal secondary data control to ensure the actual shape effect after startup.

[0058] To address strip misalignment and breakage incidents during product testing, control measures typically involve increasing tension and the number of passes. Due to the high rolling force, the strip edges are prone to slight edge cracking defects, especially in extremely thin, cold-rolled strips. Under high tension, there is a risk of edge cracking and breakage, while low tension carries the risk of strip misalignment. Therefore, the parameter settings for each pass must balance preventing strip misalignment with considering edge cracking and breakage. In this embodiment, the number of rolling passes per stand is increased to 6, and the reduction rate in each pass is reduced to address both strip misalignment and breakage. Specifically, while maintaining a maximum reduction rate of ≤40%, the reduction rates in each pass are ordered from highest to lowest, with the final pass controlled at 20%-40% of the reduction rate of the previous pass. Furthermore, the unit tension in each pass is controlled below 200 MPa to ensure rolling stability.

[0059] Step 13: Roll the target product using the adjusted rolling parameters for each pass, and after the last pass is completed, control the mill to start at low speed for the coiling process.

[0060] In this embodiment, in response to the incident of strip breakage during the debugging of the product, after the last rolling pass is completed, the work roll gap is opened to the maximum, the squeeze roll is fully opened, and the mill is controlled to start at a low speed. The starting speed is adjusted from 30mpm to 20mpm to ensure the stability of the start-up and facilitate the subsequent coiling process.

[0061] 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.

[0062] Based on the same inventive concept, the following embodiments disclose a strip breakage control system for cold-hardened strip steel, see below. Figure 2 The cold-hardened strip steel has a specification of 0.1*1500mm and includes:

[0063] The pass control device 21 is used to determine the rolling pass of the single stand in response to a strip breakage accident during single-stand rolling of the test product.

[0064] The parameter adjustment device 22 is used to adjust the rolling parameters of each pass in the single stand; the rolling parameters include one or more of the following: reduction amount, uncoiling tension, relative position of the rolls, and roll profile;

[0065] The work roll control device 23 is used to roll the target product using the adjusted rolling parameters of each pass, and to control the mill to start at low speed for coiling after the last pass is completed.

[0066] Preferably, the belt breakage accident includes: rolling belt breakage accident, belt misalignment breakage accident, and belt breakage accident during idle running.

[0067] Preferably, different rolling passes are used for different types of strip breakage accidents.

[0068] Preferably, the parameter adjustment device 22 is specifically used for:

[0069] The reduction in the first pass was reduced from 0.55 mm to 0.4 mm, and the unwinding tension in the first pass was reduced from 55 MPa to 35 MPa.

[0070] Adjust the mill shape control strategy for the second pass, and adjust the relative position of the shifting rolls in the second pass from 40mm to 60mm, and increase the bending roll of the work roll from 200kN to 400kN;

[0071] In the 3rd-5th or 3rd-6th passes, the work roll of the single frame is replaced with the minimum work roll with a diameter of 140mm, and the roll shape of the minimum work roll is optimized.

[0072] Preferably, the parameter adjustment device 22 is further used to: modify the mill shape control strategy of the second pass from edge wave control mode to micro edge wave mode.

[0073] Preferably, the roughness of the minimum working roll is 0.1 μm and the roll crown is 0.01 μm.

[0074] Preferably, during the acceleration of the rolling speed from 0 to 30 mpm in each pass, the rolling force is used as the starting standard for starting the machine.

[0075] Preferably, in the event of a strip breakage accident during the debugging of the product, the speed at which the rolling mill is started at a low speed for the coiling process is controlled to be below 20 mpm.

[0076] Based on the same inventive concept, the following embodiments disclose a cold-hardened strip steel with a specification of 0.1*1500mm, which is rolled using the strip breakage control method for cold-hardened strip steel described in the aforementioned scheme.

[0077] 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.

[0078] 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 breakage of cold-hardened strip steel, characterized in that, The cold-hardened strip steel has a specification of 0.

1. 1500mm, the method includes: In response to strip breakage accidents during single-stand rolling of the test product, the rolling pass of the single stand is determined. The strip breakage accidents include: strip breakage during rolling, strip breakage due to deviation, and strip breakage due to idling. Adjust the rolling parameters for each pass in the single stand; the rolling parameters include one or more of the following: reduction, uncoiling tension, relative position of shifting rolls, and roll profile; wherein, the reduction of the first pass is reduced from 0.55 mm to 0.4 mm, and the uncoiling tension of the first pass is reduced from 55 MPa. Reduce the pressure to 35 MPa; change the mill shape control strategy for the second pass from edge waviness control mode to micro edge waviness mode, and adjust the relative position of the shifting rolls in the second pass from 40 mm to 60 mm, and increase the work roll bending from 200 kN to 400 kN; in the third to fifth passes or the third to sixth passes, replace the work rolls of the single stand with the minimum work rolls with a roll diameter of 140 mm, and optimize the roll shape of the minimum work rolls, which have a roughness of 0.1 μm and a roll crown of 0.01 μm; during the acceleration of the rolling speed from 0 to 30 MPa in each pass, start the machine with constant rolling force as the starting standard; The target product is rolled using the adjusted rolling parameters for each pass, and the mill is started at low speed after the last pass is completed to perform the coiling process; wherein, in case of a strip breakage accident during the test product, the speed at which the mill is started at low speed to perform the coiling process is below 20 mpm.

2. The method as described in claim 1, characterized in that, Different rolling passes are used for different types of strip breakage accidents.

3. A strip breakage control system for cold-hardened strip steel, characterized in that, The cold-hardened strip steel has a specification of 0.

1. 1500mm, including: The pass control device is used to determine the rolling pass of the single stand in response to a strip breakage accident during single-stand rolling of the test product. The strip breakage accident includes: rolling strip breakage accident, deviation strip breakage accident, and idle running strip breakage accident. A parameter adjustment device is used to adjust the rolling parameters for each pass in the single stand; the rolling parameters include one or more of the following: reduction, uncoiling tension, relative position of shifting rolls, and roll profile; wherein, the reduction of the first pass is reduced from 0.55 mm to 0.4 mm, and the uncoiling tension of the first pass is reduced from 55 MPa. Reduce the pressure to 35 MPa; change the mill shape control strategy for the second pass from edge waviness control mode to micro edge waviness mode, and adjust the relative position of the shifting rolls in the second pass from 40 mm to 60 mm, and increase the work roll bending from 200 kN to 400 kN; in the third to fifth passes or the third to sixth passes, replace the work rolls of the single stand with the minimum work rolls with a roll diameter of 140 mm, and optimize the roll shape of the minimum work rolls, which have a roughness of 0.1 μm and a roll crown of 0.01 μm; during the acceleration of the rolling speed from 0 to 30 MPa in each pass, start the machine with constant rolling force as the starting standard; The work roll control device is used to roll the target product using the adjusted rolling parameters of each pass, and to control the mill to start at low speed for coiling after the last pass is completed; wherein, in case of a roll breakage accident during the test product, the speed at which the mill is controlled to start at low speed for coiling is below 20mpm.

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

1. 1500mm, the cold-hardened strip steel is rolled using the strip breakage control method for cold-hardened strip steel described in any one of claims 1-2.

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