Modeling method for inhibiting rolling streaks of high-grade surface cold-rolled strip steel

Abstract

The invention relates to the technical field of strip steel rolling, in particular to a method for inhibiting rolling streaks of high-grade surface cold-rolled strip steel in a modeling mode, which comprises the following steps of: controlling a rolling process according to a generation mechanism of cold-rolled rolling streak defects; cold rolling roller control; and controlling rolling lubrication. The method has the advantages that the surface rolling streak control scheme is different from a conventional high-surface-grade steel plate control method, and process parameters such as cold rolling, rollers and emulsion are finely designed on the basis of a strip steel surface appearance cold rolling whole process by analyzing a cold rolling transfer printing process and a rolling streak forming mechanism; other auxiliary equipment and a large amount of transformation are not needed; the high-surface-grade cold-rolled steel plate obtained through the process meets the use requirements of downstream users, the provided cold-rolling whole-process surface appearance refined design concept and specific process parameter requirements can be directly applied to an industrial production line, and the purposes of simplifying the production process and reducing the production cost are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of strip rolling, and particularly to a method for model-based suppression of rolling streaks on high-grade surface cold-rolled strip steel. Background Art

[0002] The latest painting process for automotive panels in the automotive industry is the two-coat painting process of 2C1B (i.e., the mid-coatless technology). 2C refers to the processes of spraying the basecoat and spraying the clearcoat, and 1B refers to the process of baking the basecoat and the clearcoat together. By eliminating the mid-coat, the mechanical properties, weather resistance, and surface decoration properties of the primer and the topcoat are improved to achieve the functions of the three-coat painting process. To meet the new generation of automotive painting requirements, higher requirements are put forward for the surface quality of automotive steel sheets for mid-coatless applications, that is, on the premise of ensuring relevant parameters such as Ra, RPc, and Wa on the strip surface, there should be no obvious visual defects on the surface.

[0003] At present, the surface topography of cold-rolled automotive steel sheets during production is mainly transferred by the work rolls of the rolling mill. Taking the five-stand cold tandem rolling mill as an example, the surface topography of the strip steel is mainly composed of two parts: the rolling streak topography transferred from the grinding marks of the work rolls of stands 1-4 and the dimpled topography transferred from the textured surface of the work roll of stand 5. Under side light conditions on the surface of the cold-rolled strip steel after rolling, rolling streaks along the rolling direction can be observed. However, with the continuous popularization of the mid-coatless process, on the one hand, the requirements for strip surface parameters are more stringent, and the transfer rate of the work rolls of the rolling mill is continuously increasing. On the other hand, the requirements for strip surface quality are more stringent, and the traditional rolling streak topography on the strip surface is gradually not acceptable to downstream manufacturers. Therefore, designing a method for suppressing rolling streaks on high-grade surface cold-rolled strip steel is of great significance for the automotive steel products to adapt to the technological upgrading of downstream users.

[0004] In the prior art, the publication number is CN114182079A, which discloses a method for controlling the surface rolling pattern of cold-rolled deep-drawing steel for outer plates. The method is characterized in that, during the production of cold-rolled deep-drawing steel, the hot continuous rolling process, the pickling continuous rolling process, and the continuous annealing process are controlled. The specific steps are as follows: (1) In the hot continuous rolling process, seven-stand continuous rolling is adopted. Rolling lubrication is applied to the F2 - F6 stands. The oil flow rate of the upper rows of the F2 - F5 stands is set to 20 ml / min, and the oil flow rate of the lower rows is set to 30 ml / min. The oil flow rate of the upper row of the F6 stand is set to 30 ml / min, and the oil flow rate of the lower row is set to 35 ml / min. The reduction rate of the F7 final stand is 13% - 20%, and the work roll life of the F7 stand is 10 - 40 km. (2) In the pickling continuous rolling process, five-stand continuous rolling is adopted. The roughness of the work rolls of the F1 - F4 stands when put into operation is 0.75 - 0.85 μm, 0.75 - 0.85 μm, 0.55 - 0.65 μm, and 0.45 - 0.55 μm respectively. The roughness of the work roll of the F5 final stand when put into operation is 3.20 - 3.50 μm. The work roll life of the F1 - F5 stands does not exceed 1200 tons, the intermediate roll life of the F1 - F5 stands does not exceed 10000 tons, the backup roll life of the F1 - F3 stands does not exceed 90000 tons, and the backup roll life of the F4 - F5 stands does not exceed 80000 tons. The light reduction of the F5 final stand improves the surface of the strip steel, and the reduction rate is 3.5% - 5.0%. (3) For the continuous annealing process, the difference in the roll diameters of the upper and lower work rolls when put into operation does not exceed 0.12 mm, the roughness is 2.20 - 2.50 μm, and the peak number is not less than 105 / cm. The concentration of the skin pass lubricant is 2.0% - 4.5%, the skin pass elongation is 0.6% - 1.0%, and the skin pass flatness force is controlled within 2000 - 6000 KN. The control measures in the hot rolling process of this solution mainly include rolling lubrication, reduction rate, and roll life, and there are no requirements for the flatness and convexity of the hot-rolled strip steel. These two parameters have a greater impact on the fluctuations of the rolling parameters during the cold rolling process and the surface of the strip steel. Moreover, scale will form on the surface of the hot-rolled strip steel after cooling, and the surface morphology of the strip steel after pickling has little correlation with the hot rolling. Among the control measures in the cold rolling process, there are no requirements for other surface parameters of the rolls except Ra, and the design of the main parameters is for a five-stand all six-high rolling mill, which is not applicable to a four-high rolling mill. At the same time, there are no requirements for the cold rolling lubrication process closely related to transfer. For the work roll parameters in the skin pass process, rolling streaks need to be eliminated after skin pass. However, with the solution of the present invention, visible rolling streaks can be eliminated on the surface of the cold-rolled steel plate after cold rolling.

[0005] Publication number CN111085542A discloses a method for improving pitting defects on the surface of cold-rolled 316L stainless steel. In the hot rolling step, ICDP rolls and HSS rolls are used, the roll unit sequence of the ICDP roll < 9, and the roll unit sequence of the HSS roll < 18; the heating temperature of the annealing furnace is 1060 ± 20 °C; the projection speed of the shot blasting machine is 2100 r / min and the projection amount is 850 kg / min; in the hot annealing pickling section, the acid concentration in each acid tank is HF > 35 g / l, and the pickling section speed < (240 / material thickness mm) m / min; in the cold rolling step, Sendzimir mill is used, the reduction rate of the first pass of cold rolling < 23% and the rolling speed of the first pass decreases by 20%. The beneficial effect of this invention is that the designed projection speed of the shot blasting machine improves the descaling efficiency and reduces the surface roughness of the material; the cold rolling process is optimized to avoid small defects such as rolling folds caused by large roughness. However, the control of the surface quality depends on the shot blasting machine equipment for online continuous production, and large-scale transformation is required for other production lines to achieve it.

[0006] Publication number CN107008758B discloses an online control method and system for the high-precision shape and surface roughness of cold-rolled strip steel. It includes the following steps: S1: Calculate the strip steel surface roughness deviation value △m between the measured value m-(act) of the strip steel surface roughness m and the target value m-(ref) of the strip steel surface roughness; S2: Determine the strip steel temper rolling force adjustment amount: According to the strip steel surface roughness deviation value △m obtained in step S1, determine the strip steel temper rolling force adjustment amount △P; S3: Determine the strip steel temper tension adjustment amount: According to the strip steel temper rolling force adjustment amount △P obtained in step S2, determine the temper inlet tension adjustment amount △T-0 or the temper outlet tension adjustment amount △T-1; S4: Determine the strip steel temper work roll bending force adjustment amount: According to the strip steel temper rolling force adjustment amount △P obtained in step S2, determine the temper work roll bending force adjustment amount △S; S5: Determine whether to output the strip steel rolling force adjustment amount: Compare the absolute value |△m| of the strip steel surface roughness deviation value obtained in step S1 with the corresponding closed-loop control threshold △m-(lim) of the strip steel surface roughness, where △m-(lim) > 0; when |△m| ≥ △m-(lim), go to step S2 to adjust the strip steel temper rolling force; when |△m| < △m-(lim), there is no need to adjust the strip steel temper rolling force. This invention realizes the control of the strip steel surface roughness through the refined control of the tempering process, but this invention does not control the cold rolling process and cannot realize the control of the surface morphology of the cold-rolled steel plate after rolling. Summary of the Invention

[0007] The object of the present invention is to provide a method for model-based suppression of rolling streaks on the surface of high-grade cold-rolled strip steel, which can effectively control the rolling streak defects on the surface after rolling without other auxiliary equipment and a large amount of transformation, simplify the production process, and reduce the production cost.

[0008] To achieve the above object, the present invention is realized through the following technical solutions:

[0009] A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel, comprising:

[0010] S1. Rolling process control: According to the generation mechanism of cold-rolled rolling streak defects, the reduction ratio of each stand is iteratively optimized through the gradient descent algorithm. The formula is as follows:

[0011]

[0012] In formula ①, S1~S T represents the degree of rolling streak defects, α1~α5 respectively represent the coefficients of rolling streak increments of the 1#~5# stands; β represents the coefficient of rolling streak transfer effect between the 1# and 2# stands; γ3, γ4 are the coefficients of rolling streak reduction effects of the 3# and 4# stands; c1~c4, n1~n4 respectively represent the fitting coefficients of the non-linear function; L1~L4 respectively represent the reduction ratios of the 1-4# stands, L 01 ~L 04 respectively represent the original values of the reduction ratios of the 1-4# stands; R1~R5 respectively represent the roughnesses of the work rolls of the 1-5# stands, and RPc is the surface roughness profile coefficient of the work roll of the 5# stand;

[0013] S2. Cold-rolled roll control;

[0014] S3. Rolling lubrication control.

[0015] In S1, the rolling process control includes:

[0016] S11. Reduce the reduction ratios of the 1# stand and the 2# stand to reduce the transfer of streak morphology;

[0017] S12. Increase the reduction ratios of the 3# stand and the 4# stand to improve the coverage of surface rolling streak defects;

[0018] S13. When the reduction ratios of the 1# stand~5# stands all increase, increase the reduction ratios of the 3# stand and the 4# stand.

[0019] When the cold-rolled rolling reduction ratio is 75~80%, the reduction ratio of the 1# stand is controlled to be 20~22%, the reduction ratio of the 2# stand is controlled to be 22~24%, the reduction ratio of the 3# stand is controlled to be 19~21%, the reduction ratio of the 4# stand is controlled to be 14~16%, and the reduction ratio of the 5# stand is controlled to be 0.4~0.6%;

[0020] When the cold rolling reduction ratio is 80 - 85%, the reduction ratio of the 1# stand is controlled at 21 - 22%, the reduction ratio of the 2# stand is controlled at 21 - 23%, the reduction ratio of the 3# stand is controlled at 22 - 23%, the reduction ratio of the 4# stand is controlled at 16 - 18%, and the reduction ratio of the 5# stand is controlled at 0.4 - 0.6%.

[0021] In S2, the control of cold rolling rolls includes:

[0022] S21. The work rolls of the 1# stand to the 5# stand are ground three times with a rough grinding amount of 70%, a medium grinding amount of 20%, and a finish grinding amount of 10%;

[0023] S22. After grinding, the work roll of the 5# stand is treated with EDT texturing and SF superfinishing, and a ceramic material is selected as the grinding wheel;

[0024] S23. The service life of the work rolls of the 1# stand to the 4# stand is ≤ 3000t, and the service life of the work roll of the 5# stand is ≤ 280km.

[0025] The surface roughness Ra of the work roll of the 1# stand is 0.7 - 0.9μm, the surface roughness Ra of the work roll of the 2# stand is 0.6 - 0.8μm, the surface roughness Ra of the work roll of the 3# stand is 0.5 - 0.7μm, the surface roughness Ra of the work roll of the 4# stand is 0.4 - 0.6μm, the surface roughness Ra of the work roll of the 5# stand is 3.05 - 3.45μm, the surface roughness RPc ≥ 80, and the waviness Wa ≤ 0.5μm.

[0026] In S3, for the control of rolling lubrication, cationic emulsion is used for process lubrication, the emulsion concentration is 1.8 - 2.75%, and the emulsion temperature is 50 - 55°C.

[0027] For the cold-rolled strip steel, in terms of the mass percentage of chemical components in the steel: C ≤ 0.10, Mn ≤ 0.45, P ≤ 0.030, S ≤ 0.030, and the balance is Fe and other inevitable impurities. The yield strength of the finished product is ≥ 115MPa, the tensile strength is ≥ 270MPa, and the elongation is ≥ 40%.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The surface rolling streak control scheme of the present invention is different from the control methods of high-surface-grade steel plates in the past. Through the analysis of the cold rolling transfer process and the formation mechanism of rolling streaks, based on the strip steel surface topography, the process parameters such as cold rolling, rolls, and emulsion are finely designed throughout the whole process of cold rolling, and it can be completed without other auxiliary equipment and a large number of modifications;

[0030] 2. The cold-rolled steel sheet with a high surface grade obtained by using the process of the present invention meets the usage requirements of downstream users. The refined design concept of the surface topography in the entire cold-rolling process and the specific process parameter requirements proposed can be directly applied to industrial production lines, achieving the purpose of simplifying the production process and reducing production costs. Description of the Drawings

[0031] Figure 1 It is the state of the rolling streaks on the strip surface before and after application. Detailed Embodiments

[0032] The present invention will be described in detail below with reference to the drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0033] A method for model-based suppression of rolling streaks on cold-rolled strip steel with a high-grade surface is a cold-rolled IF steel for stamping grade. The chemical composition of the steel (by mass percentage) contains: C≤0.10, Mn≤0.45, P≤0.030, S≤0.030, and the balance is Fe and other inevitable impurities. The yield strength of the finished product is ≥115 MPa, the tensile strength is ≥270 MPa, and the elongation is ≥40%.

[0034] To effectively control the rolling streak defects on cold-rolled strip steel with a high-grade surface, it is necessary to carry out refined control of the surface topography of the strip steel throughout the cold-rolling process, mainly including the following steps:

[0035] Step S1, Rolling Process Control

[0036] According to the analysis of the generation mechanism of cold-rolled rolling streak defects, the rolling streak defects on the strip surface after being rolled by the work rolls of the 1# to 4# stands are mainly transferred from the surface streaks of the roll after grinding, and the transfer of the strip surface topography by the work rolls of the subsequent stands can effectively cover the rolling streak topography formed by the transfer of the previous stands. Since the transfer rate of the work rolls of the 1# and 2# stands to the strip surface is relatively large, and the transfer rate of the 3# and 4# stands continuously decreases, compared with the conventional compression ratio distribution, the content is as follows:

[0037] Reduce the compression ratio of the 1# and 2# stands to reduce the transfer of the streak topography, and increase the compression ratio of the 3# and 4# stands to improve the coverage of the surface rolling streak defects. When the overall compression ratio increases, further increase the compression ratio of the 3# and 4# stands. After adjusting the rolling load distribution, the unit tension of each stand can be appropriately increased according to the actual rolling situation;

[0038] According to the defect generation mechanism and combined with on-site practical experience, a gradient descent algorithm is formed, and Formula ① is as follows:

[0039]

[0040] In Formula ①, S1 to S TIt represents the degree of rolling streak defects. α1 to α5 respectively represent the coefficients of the rolling streak increments of the 1st to 5th stands; β represents the coefficient of the rolling streak transfer effect between the 1st and 2nd stands; γ3 and γ4 are the coefficients of the rolling streak reduction effects of the 3rd and 4th stands; c1 to c4, n1 to n4 respectively represent the fitting coefficients of the non-linear functions; L1 to L4 respectively represent the reduction ratios of the 1st - 4th stands, and L 01 ~L 04 respectively represent the original values of the reduction ratios of the 1st - 4th stands; R1 to R5 respectively represent the roughnesses of the work rolls of the 1st - 5th stands, and RPc is the surface roughness profile coefficient of the work roll of the 5th stand.

[0041] The rolling parameters are iteratively optimized through the gradient descent algorithm. The database formed by the algorithm and the calculation results is imported into the secondary control system, and the required rolling parameters are automatically calculated according to the rolling requirements and transmitted to the primary control system to achieve the model-based control of the rolling parameters.

[0042] After fitting formula ① according to the actual on-site process parameters and the actual measured data, the reduction ratios of each stand are iteratively optimized through the gradient descent algorithm. The implementation of the code will be described in the embodiments. After combining with on-site practice, the optimal design scheme for a certain grade of cold-rolled IF steel for stamping is as follows:

[0043] When the cold-rolled reduction ratio is 75 - 80%, the reduction ratio of the 1st stand is controlled at 20 - 22%, the reduction ratio of the 2nd stand is controlled at 22 - 24%, the reduction ratio of the 3rd stand is controlled at 19 - 21%, the reduction ratio of the 4th stand is controlled at 14 - 16%, and the reduction ratio of the 5th stand is controlled at 0.4 - 0.6%; when the cold-rolled reduction ratio is 80 - 85%, the reduction ratio of the 1st stand is controlled at 21 - 22%, the reduction ratio of the 2nd stand is controlled at 21 - 23%, the reduction ratio of the 3rd stand is controlled at 22 - 23%, the reduction ratio of the 4th stand is controlled at 16 - 18%, and the reduction ratio of the 5th stand is controlled at 0.4 - 0.6%.

[0044] Step S2, Cold-rolled roll control

[0045] According to the above model, the roughnesses of the 1st - 5th work rolls can also be optimized. After combining with on-site practice, the optimal design scheme for a certain grade of cold-rolled IF steel for stamping is as follows:

[0046] The Ra of the 1st work roll is 0.7 - 0.9 μm, the Ra of the 2nd work roll is 0.6 - 0.8 μm, the Ra of the 3rd work roll is 0.5 - 0.7 μm, the Ra of the 4th work roll is 0.4 - 0.6 μm, the Ra of the 5th work roll is 3.05 - 3.45 μm, RPc ≥ 80, and Wa ≤ 0.5 μm.

[0047] For the work rolls of stands 1# to 5#, three grinding passes are carried out with a rough grinding amount of 70%, an intermediate grinding amount of 20%, and a finish grinding amount of 10%. After grinding, the work roll of stand 5 is treated with EDT texturing and SF superfinishing. The grinding wheel is selected from ceramic materials. The service life of the work rolls of stands 1 - 4# is ≤3000t, and the service life of the work roll of stand 5# is ≤280km.

[0048] According to the analysis of the generation mechanism of cold rolling strip marks defects, the transfer process of the rear stands has an obvious effect of breaking the larger-sized strip marks formed by the transfer of the front stands. Especially for the work rolls of stands 3#, 4# and the texturing roll of stand 5#, when the size of the strip marks is reduced to a certain extent, it can be considered that the strip mark defects are effectively controlled. Therefore, compared with the Ra design of conventional work rolls, the Ra of work rolls 1# and 2# with higher transfer rates is reduced, the Ra design of work rolls 3# and 4# is precisely controlled to ensure the coverage of strip marks, and the RPc value design of work roll 5# is improved to further enhance the effect of the texturing pit morphology on breaking strip marks. At the same time, the service life of the work rolls of each stand is limited to prevent the reduction of Ra at the end of the roll usage from inhibiting the coverage effect of the rear stands on strip marks. In summary, on the premise of ensuring rolling stability, the above rolling process design scheme is adopted.

[0049] Step S3: Rolling lubrication control

[0050] Cationic emulsions are used for process lubrication, with the emulsion concentration being 1.8 - 2.75% and the emulsion temperature being 50 - 55°C. Emulsion parameters are the key factors affecting rolling lubrication. Unreasonable setting of the emulsion concentration and emulsion temperature will change the lubrication state of the strip surface to dry friction or over-lubrication, which is not conducive to the transfer of surface topography and the control of strip marks.

[0051] The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The methods used in the following embodiments are conventional methods unless otherwise specified.

[0052] Embodiment

[0053] The present invention is described in more detail through embodiments. These embodiments are only descriptions of the best implementation manners of the present invention and do not limit the scope of the present invention in any way. C≤0.10, Mn≤0.45, P≤0.030, S≤0.030

[0054] The chemical composition of the implemented steel is shown in Table 1.

[0055] Table 1 Chemical composition of the steel plate in the embodiment

[0056]

[0057] The cold rolling load distribution of the embodiment is shown in Table 2.

[0058] Table 2 Rolling Load Distribution of Embodiments

[0059]

[0060] The parameters of the cold rolling work rolls in the embodiments are shown in Table 3.

[0061] Table 3 Parameters of Cold Rolling Work Rolls

[0062]

[0063] The cycle of the cold rolling work rolls corresponding to the embodiments and the rolling streak conditions are shown in Table 4.

[0064] Table 4 Cycle of Cold Rolling Work Rolls and Rolling Streaks

[0065]

[0066] The state of the rolling streaks on the strip steel surface before and after applying the present invention can be seen in Figure 1 , (a) Before application; (b) After application.

[0067] It can be seen from the above embodiments that by using the rolling streak control method of the present invention, the surface quality of the cold-rolled steel sheet with a high surface grade is good, without rolling streak defects, meeting the production requirements of downstream enterprises.

[0068] The algorithm for iteratively optimizing the compression ratio of each stand through the gradient descent algorithm is as follows. The algorithm for optimizing the roughness of each stand is similar, and will not be repeated here.

[0069]

[0070]

[0071] The surface rolling streak control scheme of the present invention is different from the conventional control methods for high-surface-grade steel sheets. Through the analysis of the cold rolling transfer process and the formation mechanism of rolling streaks, based on the strip steel surface topography, the process parameters such as cold rolling, roll, and emulsion are refinedly designed throughout the whole process. It can be completed without other auxiliary equipment and a large number of modifications; the high-surface-grade cold-rolled steel sheet obtained by using the process of the present invention meets the usage requirements of downstream users. The refined design concept of the surface topography throughout the cold rolling process and the specific process parameter requirements can be directly applied to industrial production lines, achieving the purpose of simplifying the production process and reducing production costs.

Claims

1. A method for modeling and suppressing rolling streaks on high-grade cold-rolled strip steel surfaces, characterized in that, Including: S1. Rolling process control: According to the generation mechanism of cold rolling streak defects, the reduction ratio of each stand is iteratively optimized through the gradient descent algorithm. The formula is as follows: In Formula ①, S1~S T represents the degree of rolling streak defects, α1~α5 respectively represent the coefficients of rolling streak increments of the 1#~5# stands; β represents the coefficient of rolling streak transfer effect between the 1# and 2# stands; γ3, γ4 are the coefficients of rolling streak reduction effect of the 3# and 4# stands; c1~c4, n1~n4 respectively represent the fitting coefficients of the non-linear function; L1~L4 respectively represent the reduction ratios of the 1-4# stands, L 01 ~L 04 ~L respectively represent the original values of the reduction ratios of the 1-4# stands; R1~R5 respectively represent the work roll roughnesses of the 1-5# stands, and RPc is the surface roughness profile coefficient of the work roll of the 5# stand; S2. Cold rolling roll control; S3. Rolling lubrication control.

2. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 1, characterized in that, In S1, the rolling process control includes: S11. Reducing the reduction ratio of Stand 1 and Stand 2 to reduce the transfer of streak morphology; S12. Increasing the reduction ratio of Stand 3 and Stand 4 to improve the coverage of surface rolling streak defects; S13. When the reduction ratios of Stand 1 to Stand 5 all increase, increasing the reduction ratios of Stand 3 and Stand 4.

3. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 2, characterized in that, When the cold rolling reduction ratio is 75 - 80%, the reduction ratio of Stand 1 is controlled at 20 - 22%, the reduction ratio of Stand 2 is controlled at 22 - 24%, the reduction ratio of Stand 3 is controlled at 19 - 21%, the reduction ratio of Stand 4 is controlled at 14 - 16%, and the reduction ratio of Stand 5 is controlled at 0.4 - 0.6%; When the cold rolling reduction ratio is 80 - 85%, the reduction ratio of Stand 1 is controlled at 21 - 22%, the reduction ratio of Stand 2 is controlled at 21 - 23%, the reduction ratio of Stand 3 is controlled at 22 - 23%, the reduction ratio of Stand 4 is controlled at 16 - 18%, and the reduction ratio of Stand 5 is controlled at 0.4 - 0.6%.

4. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 1, characterized in that, In S2, the cold rolling roll control includes: S21. The work rolls of Stand 1 to Stand 5 are ground three times with a rough grinding amount of 70%, a medium grinding amount of 20%, and a finish grinding amount of 10%; S22. After grinding, the work roll of Stand 5 is treated with EDT texturing and SF superfinishing, and the grinding wheel is selected as ceramic material; S23. The service life of the work rolls of Stand 1 to Stand 4 is ≤ 3000t, and the service life of the work roll of Stand 5 is ≤ 280km.

5. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 4, characterized in that, The surface roughness Ra of the work roll of Stand 1 is 0.7 - 0.9μm, the surface roughness Ra of the work roll of Stand 2 is 0.6 - 0.8μm, the surface roughness Ra of the work roll of Stand 3 is 0.5 - 0.7μm, the surface roughness Ra of the work roll of Stand 4 is 0.4 - 0.6μm, the surface roughness Ra of the work roll of Stand 5 is 3.05 - 3.45μm, the surface roughness RPc ≥ 80, and the waviness Wa ≤ 0.5μm.

6. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 1, characterized in that, In S3, for the rolling lubrication control, cationic emulsions are used for process lubrication, with the emulsion concentration being 1.8 - 2.75% and the emulsion temperature being 50 - 55°C.

7. A method for modeling and suppressing rolling streaks on high-grade surface cold-rolled strip steel according to claim 1, characterized in that, For the cold-rolled strip steel, in terms of the mass percentage of chemical components in the steel: C ≤ 0.10, Mn ≤ 0.45, P ≤ 0.030, S ≤ 0.030, and the balance is Fe and other inevitable impurities. The yield strength of the finished product is ≥ 115MPa, the tensile strength is ≥ 270MPa, and the elongation is ≥ 40%.

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