Leveling control method for variable tension of DP980 hot-rolled high-strength steel

Abstract

The invention provides a flattening control method for variable tension of DP980 hot-rolled high-strength steel. The flattening control method comprises the following steps that firstly, related data of the flattening process of the DP980 high-strength steel are collected; 2, under the condition that the rolling force and the roll bending force of the temper mill are constant, the uncoiling tension of the steel coil in the three stages of leveling the outer ring, the middle ring and the inner ring is calculated; and 3, the steel coil leveling process of the corresponding stage is adjusted according to the calculation result of the uncoiling tension. According to the method, the uncoiling tension of the steel coil in the outer ring flattening stage, the middle ring flattening stage and the inner ring flattening stage is calculated, the uncoiling tension is adjusted according to the calculation result, the probability of DP980 hot-rolled strip steel contusion is remarkably reduced, flattening abnormal cutting is reduced, and the flattening yield is greatly increased.

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 with specifications below 2.7mm often face the problem of surface contusion caused by loose coils during flattening, and the surface quality does not meet the requirements. Strip steel contusion is determined by the degree of loose coiling, the state of the flattening equipment, and the flattening parameter settings. The inner circle is as short as 20 meters and as long as 300 meters. It is a big uncertainty hidden danger, causing great economic losses.

[0003] Operators from different teams have different settings for parameters such as tension and speed. The same operator has different habits when leveling different coils. Sometimes, they make special adjustments because the working conditions have changed, and sometimes they fail to make adjustments because they cannot clearly judge the changes in working conditions. But more often, it is because there is no clear adjustment strategy, which leads to unstable leveling yield rates. The leveling parameters within the entire length of the strip are sometimes set to be fixed, which is not conducive to solving the DP980 leveling contusion problem. If the unwinding tension is set very high throughout the process, then the layers may shift when the coil is unwinding and the coil is built. At this time, there are many layers of steel coils, so the position of the shift between the layers is likely to appear within 20-300 meters of the inner circle of the steel coil, causing serious contusion. In addition, if the unwinding tension is set very low throughout the process, then when the head plate shape is poor, the strip will easily deviate, bringing the risk of rolling.

[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. Through process optimization and parameter redesign, the occurrence of loose coiling of the flat inner diameter is reduced without increasing equipment investment, and the rate of unqualified products due to loose coiling and other secondary defects such as abrasions caused by loose coiling are reduced. Patent CN201910506910.X discloses a method for preventing the contusion of strip steel in a hot-rolled flat-rolling line. The process of uncoiling is optimized, the contusion rate of strip steel in the hot-rolled flat-rolling line is reduced, and the yield rate of the flattened area is increased, which 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 is made in view of the above problems, and its purpose is to provide a flattening control method for DP980 hot-rolled high-strength steel with variable tension, by calculating the unwinding tension of the three stages of the outer ring, middle ring and inner ring of the steel coil and adjusting the unwinding tension according to the calculation results, the probability of DP980 hot-rolled strip steel frustration is significantly reduced, the abnormal removal of flattening is reduced, and the flattening yield rate is greatly improved. The application of the present invention not only improves production efficiency, but also greatly reduces production costs and reduces resource consumption in the production process.

[0006] Specifically, the first aspect of the present application provides a flatness control method for 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 is a kind of steel with high strength and good toughness, which is widely used in automobile, aerospace and machinery manufacturing. This steel belongs to dual-phase steel (DP steel). DP980 steel has a tensile strength of 980MPa and a high yield strength, and also has good elongation and processing performance.

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

[0010]

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

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

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

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

[0015] T 0 Indicates the initial setting tension of the outer ring, in kN;

[0016] h 0 Represents the thinnest flat specification, unit: mm;

[0017] b 0 Represents the narrowest flatness specification, unit: mm;

[0018] T 1 Indicates the set tension of the middle ring, in kN;

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

[0020] l 0 Indicates the length of the steel coil, in m;

[0021] k h Indicates the influence coefficient of strip thickness;

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

[0023] k 1 Indicates the influence coefficient of the unwinding length of the outer ring of the steel coil;

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

[0025] Step 3: Adjust the coil leveling process at the corresponding stage according to the calculation result of the uncoiling tension.

[0026] Uncoiling tension refers to the tension applied during the uncoiling process of the strip steel coil. The magnitude of this tension depends on the product status, specifications and requirements for the product. If the tension is too large, the investment in transmission equipment will increase; if the tension is too small, it is easy to cause the strip to deviate and affect 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 uncoiling length refers to the length of the steel coil that is unfolded during the uncoiling process. Therefore, when the uncoiling length is small, the outer ring of the steel coil is flattened. As the uncoiling length increases, the middle and inner rings are gradually flattened. This length usually depends on the original length of the steel coil and the needs of subsequent processing. On the hot-rolled plate production line, the steel coil undergoes steps such as uncoiling, leveling, and shearing to eventually form a flat plate of the required length. Control of the uncoiling length is crucial to ensuring product quality and meeting production needs.

[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, the h, b, h 0 , b 0 , l 0 All are determined by the actual flatness specifications of the production line.

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

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

[0033] When flattening 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 ~ 60kN.

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

[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 a maximum value within a range of a flattening stage, the uncoiling tension T reaches a maximum value within a range of a 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 influence coefficient 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, which will not be repeated here. The function can be implemented by hardware, or by executing the corresponding software implementation 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 the third aspect, the present application also provides a computing device, which is used to implement 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 function 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, in which instructions are stored, and when the computer-readable storage medium is run on a computer, the computer executes 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 the chip is used to read and execute a software program stored in the memory, and to execute the methods in the above-mentioned first aspect and various possible implementation methods 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 diagram of the unwinding tension curve of 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 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 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 figure will be further described in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0055] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient 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] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means 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), which means 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] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0060] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": 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 steel with high strength and good toughness, which is widely used in the fields of automobile, aerospace and machinery manufacturing. This steel belongs to dual-phase steel (DP steel). The tensile strength of DP980 steel reaches 980MPa, the yield strength is high, and it also has good elongation and processing performance.

[0063] (2) Uncoiling tension refers to the tension applied during the uncoiling process of the strip steel coil. The magnitude of this tension depends on the product status, specifications and requirements for the product. If the tension is too large, the investment in transmission equipment will increase; if the tension is too small, it is easy to cause the strip to deviate and affect product quality.

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

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

[0066] DP980 high-strength steel is a kind of steel with high strength and good toughness, which is widely used in automobile, aerospace and machinery manufacturing. This steel belongs to dual-phase steel (DP steel). DP980 steel has a tensile strength of 980MPa and a high yield strength, and also has good elongation and processing performance.

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

[0068]

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

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

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

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

[0073] T 0 Indicates the initial setting tension of the outer ring, in kN;

[0074] h 0 Represents the thinnest flat specification, unit: mm;

[0075] b 0 Represents the narrowest flatness specification, unit: mm;

[0076] T 1 Indicates the set tension of the middle ring, in kN;

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

[0078] l 0 Indicates the length of the steel coil, in m;

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

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

[0081] k 1 Indicates the influence coefficient of the unwinding length of the outer ring of the steel coil;

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

[0083] Step 3: Adjust the coil leveling process at the corresponding stage according to the calculation result of the uncoiling tension.

[0084] Uncoiling tension refers to the tension applied during the uncoiling process of the strip steel coil. The magnitude of this tension depends on the product status, specifications and requirements for the product. If the tension is too large, the investment in transmission equipment will increase; if the tension is too small, it is easy to cause the strip to deviate and affect 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 uncoiling length refers to the length of the steel coil that is unfolded during the uncoiling process. Therefore, when the uncoiling length is small, the outer ring of the steel coil is flattened. As the uncoiling length increases, the middle and inner rings are gradually flattened. This length usually depends on the original length of the steel coil and the needs of subsequent processing. On the hot-rolled plate production line, the steel coil undergoes steps such as uncoiling, leveling, and shearing to eventually form a flat plate of the required length. Control of the uncoiling length is crucial to ensuring product quality and meeting production needs.

[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, h 0 , b 0 , l 0 All are determined by the actual flatness specifications of the production line.

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

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

[0091] When flattening 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 ~ 60kN.

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

[0094] Furthermore, the unwinding tension of the middle ring 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 a maximum value within a range of a flattening stage, the uncoiling tension T reaches a 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 hIt 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 influence coefficient of strip width change on rolling force, which is set by the specific rolling data of the production line.

[0099] In this embodiment, according to the actual flat specifications of the production line, the actual strip thickness ranges from 2.2 mm to 2.9 mm, and the actual strip width ranges from 920 mm to 1475 mm; therefore, h 0 = = 2.2 mm, b 0 =920mm, coil length l 0 =900mm.

[0100] When flattening the outer ring of the steel coil, the inner ring was observed to have a loose coil problem, so the outer ring tension range is 40kN~50kN, T 0 =40kN; According to the value range of unwinding tension, T 1 =65kN; T′ 0 =80kN.

[0101] Statistics on the uncoiling tension and flattening yield of strip steel with 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] Get k 1 =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 circle. According to the calculation formula of the unwinding tension, it is obtained:

[0106]

[0107] Get k′ 1 =0.0626333.

[0108] The calculation formula of 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 only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining 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 high-strength steel; Step 2: Under the condition that the rolling force and bending force of the leveling mill are constant, the unwinding tension of the steel coil leveling outer ring, middle ring and inner ring is calculated. The formula is as follows: Where: T represents the unwinding tension, unit is kN; h represents the strip thickness, in mm; b represents the strip width, in mm; l represents the unwinding length, in m; T0 represents the initial setting tension of the outer ring, in kN; h0 represents the thinnest flatness specification, unit: mm; b0 represents the narrowest flatness specification, in mm; T1 represents the set tension of the middle ring, in kN; T′0 represents the initial setting tension of the inner ring, in kN; l0 represents the length of the steel coil, in m; k h Indicates the influence coefficient of strip thickness; k b Indicates the influence coefficient of strip width; k1 represents the influence coefficient of the unwinding length of the outer ring of the steel coil; k′1 represents the influence coefficient of the unwinding length of the inner ring of the steel coil. Step 3: Adjust the coil leveling process at the corresponding stage according to the calculation result of the uncoiling tension.

2. A 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, h0, b0, and l0 are all 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: T0, T0 ′ They are set to the minimum value of the outer ring tension value range and the minimum value of the inner ring tension value range respectively.

5. A 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, 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; If the inner ring is not loose, the outer ring tension range is 50kN ~ 60kN.

6. A 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 to 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: The unwinding tension of the middle ring has a value range of 60 kN to 70 kN.

8. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: The uncoiling tension T is positively correlated with the strip thickness, strip width and uncoiling length.

9. A method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 8, 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.

10. The method for controlling the leveling of DP980 hot-rolled high-strength steel with variable tension according to claim 1, characterized in that: 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.

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