A flattening control method for DP980 hot-rolled high-strength steel with variable tension

Abstract

The present invention provides a method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension, comprising the following steps: Step 1: Collecting data related to the leveling process of DP980 high-strength steel; Step 2: Calculating the uncoiling tension for the outer, middle, and inner rings of the steel coil while maintaining constant rolling and bending forces in the leveling mill; and Step 3: Adjusting the leveling process for the corresponding stages based on the calculated uncoiling tension. By calculating the uncoiling tension for the outer, middle, and inner rings of the steel coil and adjusting the uncoiling tension based on the calculated results, the present invention significantly reduces the probability of bruising of DP980 hot-rolled strip, reduces abnormal leveling removal, and significantly improves the leveling yield rate.

Description

Technical Field

[0001] The present application relates to the technical field of high-strength steel flattening, and in particular to a flattening control method for DP980 hot-rolled high-strength steel with variable tension. Background Art

[0002] DP980 steel grades under 2.7mm in size often face surface damage during strip leveling due to coil loosening, resulting in substandard surface quality. Strip steel strip damage is determined by factors such as the degree of coil loosening, the condition of the leveling equipment, and the leveling parameter settings. This damage can range from as little as 20 meters to as much as 300 meters within the inner circle, creating a significant uncertainty and hidden danger that can lead to significant economic losses.

[0003] Operators in different shifts set parameters like tension and speed differently, and the same operator's habits varied from coil to coil. Sometimes adjustments were made due to changes in working conditions, sometimes due to a failure to clearly identify the change. More often, a lack of a clear adjustment strategy led to fluctuating and unstable strip yields. Strip-leveling parameters were sometimes set to fixed across the entire strip length, which hindered efforts to address the DP980 strip-leveling damage issue. If the unwinding tension was set too high throughout the entire process, layer-to-layer shifting could occur during unwinding and strip building. In situations with a large number of coil layers, this shifting could occur within the inner 20-300 meter radius of the coil, causing severe strip damage. Alternatively, if the unwinding tension was set too low throughout the entire process, strip deviation could occur if the strip's head shape was poor, posing a risk of strip breakage.

[0004] In the prior art, patent CN202210329188.9 discloses a method for controlling the loosening of the inner diameter of the flat coiling of advanced high-strength steel. By optimizing the process and redesigning the parameters, the occurrence of loose inner diameter coiling is reduced without increasing equipment investment, and the rate of unqualified products due to loose coiling and other secondary defects such as scratches caused by loose coiling are reduced. Patent CN201910506910.X discloses a method for preventing contusion of strip steel in a hot-rolled flat-rolling line. The method optimizes the uncoiling process, reduces the contusion rate of strip steel in the hot-rolled flat-rolling line, improves the yield rate of the flattened area, and brings significant economic benefits to the flattening production of strip steel. The prior art mostly optimizes the process of the uncoiling process to reduce the contusion problem, and has no guiding role in the control of the flattening process in the hot rolling production process of steel. Summary of the Invention

[0005] This application addresses the aforementioned issues and aims to provide a variable-tension flattening control method for DP980 hot-rolled high-strength steel. By calculating the uncoiling tension during the outer, middle, and inner coil flattening stages and adjusting the uncoiling tension based on the calculated results, the method significantly reduces the probability of bruising of the DP980 hot-rolled strip, minimizes abnormal flattening removal, and significantly increases the flattening yield rate. The application of this invention not only improves production efficiency but also significantly reduces production costs and reduces resource consumption during the production process.

[0006] Specifically, the first aspect of the present application provides a method for controlling the flattening of DP980 hot-rolled high-strength steel with variable tension, comprising the following steps:

[0007] Step 1: Collect data related to the flattening process of DP980 high-strength steel;

[0008] DP980 high-strength steel, a high-strength and tough steel, is widely used in the automotive, aerospace, and machinery manufacturing industries. A dual-phase steel (DP steel), DP980 boasts a tensile strength of 980 MPa and a high yield strength, while also exhibiting good elongation and processability.

[0009] Step 2: Under the condition that the rolling force and bending force of the skin-pass mill are constant, the uncoiling tension of the outer ring, middle ring and inner ring of the steel coil is calculated. The formula is as follows:

[0010]

[0011] Where: T represents the unwinding tension, unit is kN;

[0012] h represents the thickness of the strip, in mm;

[0013] b represents the strip width, in mm;

[0014] l represents the unwinding length, in m;

[0015] T0 represents the initial setting tension of the outer ring, unit is kN;

[0016] h0 represents the thinnest flatness specification, unit: mm;

[0017] b0 represents the narrowest flatness specification, unit: mm;

[0018] T1 represents the set tension of the middle ring, unit is kN;

[0019] T′0 represents the initial setting tension of the inner ring, unit is kN;

[0020] l0 represents the length of the steel coil, in m;

[0021] k hIndicates the influence coefficient of strip thickness;

[0022] k b Indicates the strip width influence coefficient;

[0023] k1 represents the influence coefficient of the unwinding length of the outer ring of the steel coil;

[0024] k′1 represents the influence coefficient of the uncoiling length of the inner ring of the steel coil.

[0025] Step 3: Adjust the coil leveling process at the corresponding stage based on the calculation results of the uncoiling tension.

[0026] Uncoiling tension refers to the tension applied during the uncoiling process of a steel strip. The magnitude of this tension depends on the product's condition, specifications, and requirements. Excessive tension increases the investment in transmission equipment; too little tension can easily cause the strip to deviate, impacting product quality.

[0027] Furthermore, the data related to the leveling process specifically include: strip thickness, strip width, uncoiling length, coil length, outer ring initial setting tension, thinnest leveling specification, narrowest leveling specification, middle ring setting tension, and inner ring initial setting tension.

[0028] The uncoiled length refers to the length of the steel coil unwound during the uncoiling process. Therefore, when the uncoiled length is short, the outer coil is flattened. As the uncoiled length increases, the middle and inner coils are gradually flattened. This length is generally determined by the original length of the steel coil and the requirements of subsequent processing. On a hot-rolled plate production line, the steel coil undergoes uncoiling, leveling, and shearing to form a flat plate of the desired length. Controlling the uncoiled length is crucial to ensuring product quality and meeting production requirements.

[0029] The thinnest flat specification and the narrowest flat specification refer to the minimum thickness and minimum width of the strip that can be processed during the flattening process.

[0030] Furthermore, h, b, h0, b0, and l0 are all determined by the actual flatness specifications of the production line.

[0031] Furthermore, T0 and T′0 are respectively set to the minimum value of the outer ring tension value range and the minimum value of the inner ring tension value range.

[0032] Furthermore, the outer ring tension value range is determined as follows:

[0033] When leveling the outer ring of the steel coil, that is, when l≤50, it is necessary to observe the inner ring of the steel coil first. If the inner ring is loose, the outer ring tension value range is 40kN~50kN;

[0034] If the inner ring is not loose, the outer ring tension range is 50kN to 60kN.

[0035] Furthermore, the inner ring tension ranges from 80 kN to 90 kN.

[0036] Furthermore, the unwinding tension of the middle ring has a value range of 60 kN to 70 kN.

[0037] Furthermore, the uncoiling tension T is positively correlated with the strip thickness, strip width, and uncoiling length.

[0038] Furthermore, when the strip thickness and the strip width reach their maximum values, and the uncoiling length reaches the maximum value within a range of a flattening stage, the uncoiling tension T reaches the maximum value within the range of the corresponding flattening stage.

[0039] Furthermore, the k h 、k b The setting is determined by the statistics of uncoiling tension and flatness yield rate of strip steel with different width and thickness specifications.

[0040] Strip thickness influence coefficient k h It refers to the influence coefficient of the strip thickness change on the rolling force during the rolling process, and the strip width influence coefficient k b It is the coefficient of influence of strip width change on rolling force, which is set by the specific rolling data of the production line.

[0041] In the second aspect, the present application also provides a computing device, which has the function of implementing the method described in the first aspect above. The beneficial effects can be found in the description of the first aspect and will not be repeated here. The function can be implemented by hardware or by executing the corresponding software through hardware. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the structure of the device includes an acquisition module, a training module, and optionally, a construction module. These modules can implement the function of the training node in the method example of the first aspect above. Please refer to the detailed description in the method example for details, which will not be repeated here.

[0042] In a third aspect, the present application further provides a computing device for implementing the functions of the method described in the first aspect above. The beneficial effects can be found in the description of the first aspect and will not be repeated here. The structure of the computing device includes a processor and a memory, and the memory is used to store instructions and / or data. The memory is coupled to the processor, and when the processor executes the program instructions stored in the memory, the functions of the training node in the example of the first aspect above can be implemented. The structure of the computing device also includes a communication interface for communicating with other devices.

[0043] In a fourth aspect, the present application also provides a computer-readable storage medium, which stores instructions. When the computer-readable storage medium is run on a computer, it enables the computer to execute the method in the above-mentioned first aspect and various possible designs of the first aspect.

[0044] In a fifth aspect, the present application also provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method in the above-mentioned first aspect and various possible designs of the first aspect.

[0045] In a sixth aspect, the present application also provides a computing chip, which is connected to a memory and is used to read and execute software programs stored in the memory, and to execute the methods in the above-mentioned first aspect and various possible implementations of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0047] Figure 1 is a flow chart of the steps of the present invention;

[0048] Figure 2 A comparison chart of the unwinding tension curve during the whole flattening process provided by the embodiment of the present invention and the original strategy;

[0049] Figure 3 A comparison chart of the yield rate of steel coils with different thickness specifications leveled according to the present invention and the yield rate of the original leveling strategy;

[0050] Figure 4 This is a comparison chart of the yield rate of steel coils with different width specifications leveled according to the present invention and the yield rate of the original leveling strategy;

[0051] Figure 5 This is the surface condition when the inner ring of the steel coil is leveled using the original leveling strategy;

[0052] Figure 6 This is the surface condition when the inner ring of the steel coil is flattened according to the present invention.

[0053] The purpose, features and advantages of this drawing will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0055] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0056] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0057] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0058] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0059] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0060] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0061] In order to better understand the solutions of the embodiments of the present application, some relevant terms and concepts that may be involved in the embodiments of the present application are first introduced below.

[0062] (1) DP980 high-strength steel is a type of steel with high strength and good toughness, widely used in the automotive, aerospace, and machinery manufacturing industries. This steel is a dual-phase steel (DP steel). DP980 steel has a tensile strength of 980 MPa and a high yield strength, while also having good elongation and processing properties.

[0063] (2) Uncoiling tension refers to the tension applied during the uncoiling process of the strip. The magnitude of this tension depends on the product condition, specifications, and product requirements. If the tension is too high, the investment in transmission equipment will increase; if the tension is too low, it will easily cause the strip to deviate, affecting product quality.

[0064] In this embodiment, Figure 1 As shown, a flattening control method for DP980 hot-rolled high-strength steel with variable tension comprises the following steps:

[0065] Step 1: Collect data related to the flattening process of DP980 high-strength steel;

[0066] DP980 high-strength steel, a high-strength and tough steel, is widely used in the automotive, aerospace, and machinery manufacturing industries. A dual-phase steel (DP steel), DP980 boasts a tensile strength of 980 MPa and a high yield strength, while also exhibiting good elongation and processability.

[0067] Step 2: Under the condition that the rolling force and bending force of the skin-pass mill are constant, the uncoiling tension of the outer ring, middle ring and inner ring of the steel coil is calculated. The formula is as follows:

[0068]

[0069] Where: T represents the unwinding tension, unit is kN;

[0070] h represents the thickness of the strip, in mm;

[0071] b represents the strip width, in mm;

[0072] l represents the unwinding length, in m;

[0073] T0 represents the initial setting tension of the outer ring, unit is kN;

[0074] h0 represents the thinnest flatness specification, unit: mm;

[0075] b0 represents the narrowest flatness specification, unit: mm;

[0076] T1 represents the set tension of the middle ring, unit is kN;

[0077] T′0 represents the initial setting tension of the inner ring, unit is kN;

[0078] l0 represents the length of the steel coil, in m;

[0079] k h Indicates the influence coefficient of strip thickness;

[0080] k b Indicates the strip width influence coefficient;

[0081] k1 represents the influence coefficient of the unwinding length of the outer ring of the steel coil;

[0082] k′1 represents the influence coefficient of the uncoiling length of the inner ring of the steel coil.

[0083] Step 3: Adjust the coil leveling process at the corresponding stage based on the calculation results of the uncoiling tension.

[0084] Uncoiling tension refers to the tension applied during the uncoiling process of a steel strip. The magnitude of this tension depends on the product's condition, specifications, and requirements. Excessive tension increases the investment in transmission equipment; too little tension can easily cause the strip to deviate, impacting product quality.

[0085] Furthermore, the data related to the leveling process specifically include: strip thickness, strip width, uncoiling length, coil length, outer ring initial setting tension, thinnest leveling specification, narrowest leveling specification, middle ring setting tension, and inner ring initial setting tension.

[0086] The uncoiled length refers to the length of the steel coil unwound during the uncoiling process. Therefore, when the uncoiled length is short, the outer coil is flattened. As the uncoiled length increases, the middle and inner coils are gradually flattened. This length is generally determined by the original length of the steel coil and the requirements of subsequent processing. On a hot-rolled plate production line, the steel coil undergoes uncoiling, leveling, and shearing to form a flat plate of the desired length. Controlling the uncoiled length is crucial to ensuring product quality and meeting production requirements.

[0087] The thinnest flat specification and the narrowest flat specification refer to the minimum thickness and minimum width of the strip that can be processed during the flattening process.

[0088] Furthermore, h, b, h0, b0, and l0 are all determined by the actual flatness specifications of the production line.

[0089] Furthermore, T0 and T′0 are respectively set to the minimum value of the outer ring tension value range and the minimum value of the inner ring tension value range.

[0090] Furthermore, the outer ring tension value range is determined as follows:

[0091] When leveling the outer ring of the steel coil, that is, when l≤50, it is necessary to observe the inner ring of the steel coil first. If the inner ring is loose, the outer ring tension value range is 40kN~50kN;

[0092] If the inner ring is not loose, the outer ring tension range is 50kN to 60kN.

[0093] Furthermore, the inner ring tension ranges from 80 kN to 90 kN.

[0094] Furthermore, the unwinding tension of the middle coil ranges from 60 kN to 70 kN.

[0095] Furthermore, the uncoiling tension T is positively correlated with the strip thickness, strip width, and uncoiling length.

[0096] Furthermore, when the strip thickness and the strip width reach their maximum values, and the uncoiling length reaches the maximum value within a range of a flattening stage, the uncoiling tension T reaches the maximum value within the range of the corresponding flattening stage.

[0097] Furthermore, k h 、k b The setting is determined by the statistics of uncoiling tension and flatness yield rate of strip steel with different width and thickness specifications.

[0098] Strip thickness influence coefficient k h It refers to the influence coefficient of the strip thickness change on the rolling force during the rolling process, and the strip width influence coefficient k b It is the coefficient of influence of strip width change on rolling force, which is set by the specific rolling data of the production line.

[0099] In this embodiment, based on the actual flatness specifications of the production line, the actual strip thickness ranges from 2.2mm to 2.9mm, and the actual strip width ranges from 920mm to 1475mm; therefore, h0==2.2mm, b0=920mm, and the steel coil length l0=900mm.

[0100] When leveling the outer ring of the steel coil, it was observed that the inner ring had a loose coiling problem, so the outer ring tension range was 40kN~50kN, T0=40kN; according to the value range of the uncoiling tension, T1=65kN; T′0=80kN.

[0101] Statistics on the uncoiling tension and flatness yield of strip steel of different widths and thicknesses, and given the influence coefficient k h =0.1, k b =0.01.

[0102] When the strip thickness h = 2.7, width b = 1475, and unwinding length l = 50, the tension T reaches the maximum value of 50kN for the flat outer ring. According to the calculation formula of the unwinding tension, it is obtained:

[0103]

[0104] We get k1=0.1879.

[0105] When the strip thickness h = 2.7, width b = 1475, and unwinding length l = 900, the tension T reaches the maximum value of 90kN for the flat inner ring. According to the calculation formula of unwinding tension, it is obtained:

[0106]

[0107] We obtain k′1=0.0626333.

[0108] The calculation formula of the unwinding tension T is obtained as follows:

[0109]

[0110] The coil leveling process at the corresponding stage is adjusted according to the calculation results of the uncoiling tension.

[0111] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A flattening control method for DP980 hot-rolled high-strength steel with variable tension, characterized in that: The following steps are involved: Step 1: Collect data related to the flattening process of DP980 hot-rolled high-strength steel; Step 2: Under the condition that the rolling force and bending force of the skin-pass mill are constant, the uncoiling tension of the outer ring, middle ring and inner ring of the steel coil is calculated. The formula is as follows: ； Where: T represents the unwinding tension, unit is kN; h represents the thickness of the strip, in mm; b represents the strip width, in mm; Represents the unwinding length, in m; Indicates the initial setting tension of the outer ring, unit is kN; Represents the thinnest flat specification, unit: mm; Represents the narrowest specification of flatness, unit: mm; Indicates the set tension of the middle ring, unit is kN; Indicates the initial setting tension of the inner ring, unit is kN; Indicates the length of the steel coil, in m; Indicates the influence coefficient of strip thickness; Indicates the strip width influence coefficient; Indicates the influence coefficient of the uncoiling length of the outer ring of the steel coil; Indicates the influence coefficient of the uncoiling length of the inner ring of the steel coil; The unwinding tension of the middle coil ranges from 60kN to 70kN; The uncoiling tension T is positively correlated with the strip thickness, strip width, and uncoiling length; Step 3: Adjust the coil leveling process at the corresponding stage based on the calculation results of the uncoiling tension.

2. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: The data related to the leveling process specifically include: strip thickness, strip width, uncoiling length, coil length, outer ring initial setting tension, thinnest leveling specification, narrowest leveling specification, middle ring setting tension, and inner ring initial setting tension.

3. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: The h, b, 、 、 All are determined by the actual flatness specifications of the production line.

4. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: described 、 They are set as the minimum value of the outer ring tension value range and the minimum value of the inner ring tension value range respectively.

5. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 4, characterized in that: The outer ring tension value range is determined as follows: When flattening the outer ring of the steel coil, When the tension is less than or equal to 50, the inner ring of the steel coil must be observed first. If the inner ring is loose, the outer ring tension should be within the range of 40kN to 50kN. If the inner ring is not loose, the outer ring tension range is 50kN~60kN.

6. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 4, characterized in that: The inner ring tension value range is 80kN~90kN.

7. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: When the strip thickness and the strip width reach their maximum values, and the uncoiling length reaches the maximum value within a range of a flattening stage, the uncoiling tension T reaches the maximum value within the range of the corresponding flattening stage.

8. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: described 、 The setting is determined by the statistics of uncoiling tension and flatness yield rate of strip steel with different width and thickness specifications.

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